Cancer Letters - Articles in Press

Inhibition of angiogenesis by the BTB domain of promyelocytic leukemia zinc finger protein - Corrected Proof

Seung Bae Rho, Kyusam Choi, Kyoungsook Park, Je-Ho Lee — 2010-03-18

Abstract: Promyelocytic leukemia zinc finger is a negative regulator of cell cycle progression. In this study, we showed that PLZF inhibits endothelial cell angiogenesis using a human umbilical vein endothelial cell system. We also focused on characterizing the specific function of the BTB domain of PLZF as a novel apoptotic and anti-angiogenic protein via deletion mapping analysis. The BTB domain directly inhibited tube formation, as well as the biological functions of angiostatic activity in vivo, and reduced the expression of p-Akt and p-eNOS, which play a significant role in angiogenesis when stimulated by VEGF. These results strongly suggest that the BTB domain could potentially modulate the apoptotic and anti-angiogenic effects of PLZF.

3,3′-Diindolylmethane (DIM) inhibits the growth and invasion of drug-resistant human cancer cells expressing EGFR mutants - Corrected Proof

Massod Rahimi, Kai-Ling Huang, Careen K. Tang — 2010-03-18

Abstract: Epidermal Growth Factor Receptor (EGFR) mutants are associated with resistance to chemotherapy, radiation, and targeted therapies. Here we found that the phytochemical 3,3′-Diindolylmethane (DIM) can inhibit the growth and also the invasion of breast cancer, glioma, and non-small cell lung cancer cells regardless of which EGFR mutant is expressed and the drug-resistant phenotype. DIM reduced an array of growth factor signaling pathways and altered cell cycle regulators and apoptotic proteins favoring cell cycle arrest and apoptosis. Therefore, DIM may be used in treatment regimens to inhibit cancer cell growth and invasion, and potentially overcome EGFR mutant-associated drug resistance.

Autocrine production of interleukin-6 confers cisplatin and paclitaxel resistance in ovarian cancer cells - Corrected Proof

Yue Wang, Xiu Long Niu, Ye Qu, Jian Wu, Ya Qin Zhu, Wei Jia Sun, Ling Zhi Li — 2010-03-17

Abstract: It has been shown that IL-6 is elevated in the serum and ascites of ovarian cancer patients, and increased IL-6 concentration correlates with poor prognosis and chemoresistance. However, the role of IL-6 expression in the acquisition of the chemoresistance phenotype and the underlining mechanisms of drug resistance in ovarian cancer cells remain unclear. Here we demonstrate that both exogenous (a relatively short period of treatment with recombination IL-6) and endogenous IL-6 (by transfecting with plasmid encoding for sense IL-6) induce cisplatin and paclitaxel resistance in non-IL-6-expressing A2780 cells, while deleting of endogenous IL-6 expression in IL-6-overexpressing SKOV3 cells (by transfecting with plasmid encoding for antisense IL-6) promotes the sensitivity of these cells to anticancer drugs. IL-6-mediated resistance of ovarian cancer cells exhibits decreased proteolytic activation of caspase-3. Meanwhile, the further study demonstrates that the chemoresistance caused by IL-6 is associated with increased expression of both multidrug resistance-related genes (MDR1 and GSTpi) and apoptosis inhibitory proteins (Bcl-2, Bcl-xL and XIAP), as well as activation of Ras/MEK/ERK and PI3K/Akt signaling. Therefore, modulation of IL-6 expression or its related signaling pathway may be a promising strategy of treatment for drug-resistant ovarian cancer.

Histone deacetylase inhibitor FR235222 sensitizes human prostate adenocarcinoma cells to apoptosis through up-regulation of Annexin A1 - Corrected Proof

2010-03-15

Abstract: The reduction of Annexin A1 (ANXA1) expression, commonly associated with prostate cancer, could be due to elevated activity of histone deacetylases. We have investigated the mechanisms of apoptotic effects of FR235222 in LNCaP cell line and the role of ANXA1. We showed that treatment with FR235222 induced apoptosis through a caspase-dependent mechanism. FR235222 was able to increase the protein levels of ANXA1 at a transcriptional level. Finally, the inhibition of ANXA1 expression by siRNA leads to a partial reduction of FR235222-induced apoptosis. The results suggest that elevated activity of HDACs is responsible for the reduction of ANXA1, indicating that ANXA1 expression is a contributing factor to the proapoptotic effects in prostate cancer.

Potentiation of etoposide-induced apoptosis in HeLa cells by co-treatment with KG-135, a quality-controlled standardized ginsenoside formulation - Corrected Proof

2010-03-12

Abstract: Our previous studies demonstrated that KG-135, a quality-controlled red ginseng-specific formulation containing approximately equal amounts of three major ginsenosides (Rk1, Rg3 and Rg5), down-regulated G1 cyclin-dependent kinase in HeLa cells. In the present work, we have found that KG-135 potentates cytotoxicity of etoposide by modulating apoptotic signaling. Co-treatment of etoposide and KG-135 markedly elevated the expression and phosphorylation at the serine 15 residue of p53 as well as the cellular levels of Bax and p21Waf1/Cip1. The increased accumulation and phosphorylation of p53 (Ser15) were attenuated by treatment of cells with wortmannin, a pan-phosphatidylinositol-3 kinase inhibitor. Moreover, co-treatment of etoposide and KG-135 enhanced mitochondrial localization of Bax. Our results indicate that etoposide-induced apoptosis in HeLa cells can be potentiated in the presence of KG-135 through a mechanism that involves the stabilization of p53 and the stimulation of Bax- and p21-mediated apoptotic signaling pathways. These findings suggest that KG-135 represents a useful candidate adjuvant for the treatment of cancers that could potentially minimize the adverse effects of current clinical chemotherapeutics.

Vanadium in the detection, prevention and treatment of cancer: The in vivo evidence - Corrected Proof

Anupam Bishayee, Abhijeet Waghray, Mehool A. Patel, Malay Chatterjee — 2010-03-08

Abstract: Vanadium, a dietary micronutrient, is yet to be established as an essential part of the human diet. Over the past century, several biological effects of vanadium, such as insulin-mimetic action as well as amelioration of hyperlipidemia and hypertension, have been discovered. This transition element is known to influence a battery of enzymatic systems, namely phosphatases, ATPases, peroxidases, ribonucleases, protein kinases and oxidoreductases. Multiple biochemical and molecular actions of vanadium have been implicated in its inhibitory effects on various tumor cells of human origin. Successful in vitro studies over the past few decades have advanced the anticancer research on vanadium into the preclinical stage. Vanadium in several animal cancer models provides protection against all stages of carcinogenesis – initiation, promotion, and progression. This review focuses on the current advances in cancer prevention and treatment as well as early detection by vanadium compounds in preclinical animal models while pointing to possible mechanisms of such diverse beneficial effects. Clinical pharmacokinetic and potential toxicity studies on vanadium are also highlighted in this review. Supporting and challenging evidence as well as future directions of vanadium research exploring the possibility of using this dietary agent for detection, prevention and treatment of human cancers are critically discussed.

Over-expression of the Beclin1 gene upregulates chemosensitivity to anti-cancer drugs by enhancing therapy-induced apoptosis in cervix squamous carcinoma CaSki cells - Corrected Proof

Yang Sun, Jia-hua Liu, Long Jin, Sai-mei Lin, Yin Yang, Yu-xia Sui, Hong Shi — 2010-03-08

Abstract: The purpose of this study was to investigate whether the autophagy-related gene, Beclin1, plays a role in the regulation of chemosensitivity to anti-cancer drugs in cervical cancer CaSki cells. Expression of the Beclin1 protein was up-regulated in pcDNA3.1-Bec transfectants and led to cell arrest in the G0/G1 phase of the cell cycle. The MTT assay indicated that over-expression of Beclin1 sensitized CaSki cells to chemotherapeutic drugs (cisplatin, paclitaxel, 5-fluorouracil, and epirubicin) and induced greater degrees of cytotoxicity than vector-only controls. After treatment with anti-cancer drugs, flow cytometric analysis indicated that the Beclin1-transfected group showed a greater increase in apoptosis than did the non-transfected group. Furthermore, pSUPER-Bec transfectants did not lead to a significant increase of resistance to each of these anti-cancer drugs. These results suggest that Beclin1 plays an important role in the regulation of potent anti-tumor activity, and over-expression of Beclin1 in CaSki cells may enhance apoptosis signaling induced by anti-cancer drugs.

GIPC mediates the generation of reactive oxygen species and the regulation of cancer cell proliferation by insulin-like growth factor-1/IGF-1R signaling - Corrected Proof

Ji Seung Choi, A Rome Paek, Soo Youl Kim, Hye Jin You — 2010-03-08

Abstract: Insulin-like growth factor-1 (IGF-1)/IGF-1 receptor signaling participates in a variety of cellular processes, including cell survival, growth, and proliferation. Increased expression of IGF-1R and activation of its downstream signaling components have been implicated in human cancers. Although a regulatory role for IGF-1R has been established, the relationship between IGF-1R and its binding partner, GAIP-interacting protein C-terminus (GIPC), in terms of promoting cell proliferation, remains unclear. We found that siRNA-mediated silencing of GIPC expression decreased IGF-1-mediated IGF-1R phosphorylation and cellular proliferation in breast cancer models. IGF-1-mediated cellular proliferation was also inhibited by N-acetylcysteine, which implicates reactive oxygen species generation. siRNA-mediated silencing of GIPC expression also decreased IGF-1-mediated reactive oxygen species generation. Taken together, these data suggest that GIPC contributes to IGF-1-induced cancer cell proliferation via the regulation of reactive oxygen species production.

A combination of a DNA-chimera siRNA against PLK-1 and zoledronic acid suppresses the growth of malignant mesothelioma cells in vitro - Corrected Proof

2010-03-08

Abstract: Although novel agents effective against malignant mesothelioma (MM) have been developed, the prognosis of patients with MM is still poor. We generated a DNA-chimeric siRNA against polo-like kinase-1 (PLK-1), which was more stable in human serum than the non-chimeric siRNA. The chimeric PLK-1 siRNA inhibited MM cell proliferation through the induction of apoptosis. Next, we investigated the effects of zoledronic acid (ZOL) on MM cells, and found that ZOL also induced apoptosis in MM cells. Furthermore, ZOL augmented the inhibitory effects of the PLK-1 siRNA. In conclusion, combining a PLK-1 siRNA with ZOL treatment is an attractive strategy against MM.

Lunasin promotes apoptosis in human colon cancer cells by mitochondrial pathway activation and induction of nuclear clusterin expression - Corrected Proof

Vermont P. Dia, Elvira Gonzalez de Mejia — 2010-03-08

Abstract: Lunasin is a naturally occurring peptide with arginine–glycine–aspartic acid motif associated to its reported biological activity. We aimed to determine the potential of lunasin from soybean to stimulate apoptosis in HT-29 colon cancer cells. Lunasin caused cytotoxicity to HT-29 cells and induced G2/M cell cycle arrest with simultaneous increased in p21 expression. Lunasin-induced apoptosis as evidenced by a twofold increase in the percentage of cells undergoing apoptosis, decreased Bcl-2:Bax ratio from 8.5 to 0.4, increased caspase-3 activity by 77% and increased expression of pro-apoptotic nuclear clusterin by five fold when compared to untreated cells. In conclusion, lunasin stimulated apoptosis in HT-29 cells by activating apoptotic mitochondrial pathways and inducing expression of the pro-apoptotic nuclear clusterin.

Concurrent blockade of the NF-κB and Akt pathways potently sensitizes cancer cells to chemotherapeutic-induced cytotoxicity - Corrected Proof

2010-03-08

Abstract: Nuclear factor-κB (NF-κB) and Akt are two major cell survival pathways that are often constitutively activated and can be further stimulated by chemotherpeutics in cancer cells. Although individually targeting the NF-κB or Akt has been reported to sensitize caner therapy, the effectiveness of concurrent blocking these two pathways for chemosensitizing of cancer cells to genotoxic therapeutics has not been investigated. In the present study, we investigate the activation of the NF-κB and Akt pathways by two frontline anticancer drugs cisplatin and etopside in a variety of cancer cell lines. The effects of blocking these two survival pathways individually or concurrently on cisplatin- or etopside-induced cytotoxicity were detected. The results show that cisplatin and etopside activate both NF-κB and Akt in cancer cells. Blockade of either of these pathways with chemical inhibitors or siRNA moderately sensitized cancer cells to cisplatin- or etopside-induced cytotoxicity. Strikingly, much more effective potentiation of cytotoxicity to these anticancer drugs was achieved when NF-κB and Akt were concurrently blocked. These data suggest that NF-κB and Akt cooperatively attenuate therapeutic-induced cytotoxicity and concurrently blocking these pathways is an effective strategy for improving the anticancer efficacy of therapeutics.

A short-hairpin RNA targeting osteopontin downregulates MMP-2 and MMP-9 expressions in prostate cancer PC-3 cells - Corrected Proof

Hao Liu, Anmin Chen, Fengjing Guo, Lin Yuan — 2010-03-08

Abstract: Osteopontin (OPN), a secreted phosphoglycoprotein, is frequently associated with cell proliferation and tumor metastatic spread in a variety of cancers. It has been reported that OPN induce matrix metalloproteinase (MMP)-2 and MMP-9 activations through nuclear factor kappaB (NF-κB)-mediated signaling pathways. In this study, we investigated the roles of OPN in human prostate cancer cells and provided clues about the possible functions of IkappaB kinase (IKK) in NF-κB-mediated OPN-induced activations of MMP-2 and MMP-9. Short-hairpin RNA (shRNA) expression vectors were used to inhibit OPN expression in PC-3 cells, human prostate cancer cell line, and IKK inhibitor VII were applied to inhibit the activities of IKK-1 and IKK-2. The results showed that OPN shRNA-mediated RNA interference can downregulate OPN, MMP-2 and MMP-9 expressions, thereby resulting in suppression of the proliferation, migration and invasion of PC-3 cells in vitro and tumor growth in vivo. Moreover, the inhibition of IKK-2 can suppress MMP-2 and MMP-9 expressions, in contrast, the inhibition of IKK-1 has no effects on the OPN, MMP-2 and MMP-9 expression levels. Thus, this study demonstrated that OPN knockdown could downregulate MMP-2 and MMP-9 expressions result in inhibiting the malignant physiological behaviors of PC-3 cell and that IKK-2 may play a crucial role in OPN-induced MMP-2 and MMP-9 expressions via NF-κB-mediated signaling pathways.

Extracellular ATP enhances in vitro invasion of prostate cancer cells by activating Rho GTPase and upregulating MMPs expression - Corrected Proof

2010-03-04

Abstract: We previously found that in addition to anti-proliferation function, extracellular ATP had a pro-invasion effect on prostate cancer cells, and probably serves as an important regulator of invasion in local microenvironment. However, the underlying mechanism remains unclear. In this study, we demonstrated that ATP increased the motility of prostate cancer cells, and promoted formation of lamellipodia and filopodia. We also found that ATP induced activation of Rac1 and Cdc42, and promoted expression of MMP-3 and MMP-13. These data suggest that extracellular ATP enhances the invasion of prostate cancer cells by activating Rho GTPases Rac1 and Cdc42 and upregulating MMPs expression.

Novel anti-CD20 antibody TGLA with enhanced antibody-dependent cell-mediated cytotoxicity mediates potent anti-lymphoma activity - Corrected Proof

2010-03-04

Abstract: Rituximab is the first anti-cancer antibody approved by the FDA for the treatment of B-cell lymphoma. However, its efficacy remains variable and often modest. Some patients are initially unresponsive to rituximab or later develop resistance to it, and require alternative therapies. Rituximab activity has been thought to involve antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and apoptosis. Present studies suggest that the patients unresponsive to rituximab may be helped with other CD20 antibodies with enhanced activities. In this study, we characterized a novel anti-CD20 chimeric antibody, TGLA, which binds to various B-cell lines specially and shares an epitope with rituximab. TGLA shows equal activities with rituximab, such as CDC, cell growth arrest and so on. Interestingly, TGLA also shows significant ADCC activity. Immunotherapeutic studies further show that TGLA is far more effective in delaying tumor growth than rituximab. These findings suggest that the ADCC-enhanced anti-CD20 antibody TGLA might be an alternative therapeutic agent for B-cell lymphoma.

Inhibition of EGFR signaling augments oridonin-induced apoptosis in human laryngeal cancer cells via enhancing oxidative stress coincident with activation of both the intrinsic and extrinsic apoptotic pathways - Corrected Proof

2010-03-04

Abstract: Oridonin, a bioactive diterpenoid isolated from Rabdosia rubescens, has been reported to have anti-tumor effects, while the epidermal growth factor receptor (EGFR) signal pathway has been reported to play a vital role in the biological progression of several tumors and to be a target for therapeutic intervention. In this work, we show that inhibition of EGFR with tyrphostin AG1478 enhances oridonin-induced cell death in human laryngeal cancer cells HEp-2, a cell line characterized by EGFR gene amplification. The enhanced apoptotic effect correlates with high expression and activation of Bax, FADD, caspase-8 as well as caspase-3 and decreased protein levels of Bcl2 and SIRT1, suggesting that both the extrinsic and intrinsic apoptosis pathways are involved in the apoptotic processes. However, treatment with oridonin and AG1478 greatly enhances nuclear translocation of apoptosis inducing factor (AIF) without caspase-9 activation, indicating that the apoptosis occurs via a caspase-9-independent mitochondrial pathway. Here, it is the active form of caspase-8 but not caspase-9 that activates downstream effector caspase-3, resulting in the cleavage of critical cellular proteins and apoptosis. Furthermore, the combined use of AG1478 and oridonin augments the production of reactive oxygen species (ROS). Incubation of cells with N-Acetylcysteine (NAC) attenuates the apoptosis and the mitochondrial membrane potential (Δψm) disruption induced by the combination of oridonin and AG1478, which indicates that ROS plays a pivotal role in cell death. In conclusion, targeting EGFR combined with other conventional pro-apoptotic drugs should be a potentially very effective anti-neoplastic therapy for laryngeal cancer.

Alcohol consumption promotes mammary tumor growth and insulin sensitivity - Corrected Proof

Jina Hong, Valerie B. Holcomb, Samrawit A. Tekle, Betty Fan, Nomelí P. Núñez — 2010-03-04

Abstract: Epidemiological data show that in women, alcohol has a beneficial effect by increasing insulin sensitivity but also a deleterious effect by increasing breast cancer risk. These effects have not been shown concurrently in an animal model of breast cancer. Our objective is to identify a mouse model of breast cancer whereby alcohol increases insulin sensitivity and promotes mammary tumorigenesis. Our results from the glucose tolerance test and the homeostasis model assessment show that alcohol consumption improved insulin sensitivity. However, alcohol-consuming mice developed larger mammary tumors and developed them earlier than water-consuming mice. In vitro results showed that alcohol exposure increased the invasiveness of breast cancer cells in a dose-dependent manner. Thus, this animal model, an in vitro model of breast cancer, may be used to elucidate the mechanism(s) by which alcohol affects breast cancer.

Overexpression of LAPTM4B-35 promotes growth and metastasis of hepatocellular carcinoma in vitro and in vivo - Corrected Proof

Hua Yang, Fuxia Xiong, Xuanhui Wei, Yu Yang, Michael A. McNutt, Rouli Zhou — 2010-03-04

Abstract: LAPTM4B-35, encoded by Lysosomal protein transmembrane 4 beta (LAPTM4B) is over-expressed in more than 71% of hepatocellular carcinomas (HCCs) and associated with prognosis of the patients. But the exact role and molecular mechanism in HCC have not been determined. In this study, we explored the effects and mechanisms of LAPTM4B-35 on tumor growth and metastasis in vitro and in vivo by overexpression and depletion of LAPTM4B in HCC HepG2 and Bel7402 cells. These findings suggest that overexpression of LAPTM4B-35 plays a critical role in the growth and metastasis of HCC, and LAPTM4B-35 may therefore be a therapeutic target for HCC.

Therapeutic effect of MIP-1α-recruited dendritic cells on preestablished solid and metastatic tumors - Corrected Proof

2010-03-04

Abstract: We previously found that dendritic cell (DC) precursors could be recruited into the peripheral blood of B6 mice by administration of macrophage inflammatory protein (MIP)-1α. These MIP-1α-recruited DCs could induce anti-tumor protective immunity when pulsed with tumor cell lysate. In this study, MIP-1α-recruited DCs could not effectively suppress preestablished tumor when pulsed with B16 tumor cell lysate. However, inoculation with these DCs expressing MAGE-1 induced an anti-tumor immunity against preestablished solid and metastatic tumor from B16-MAGE-1 cells. These MIP-1α-recruited DCs expressed higher level of CCR7 and displayed a more significant chemotactic response toward secondary lymphoid tissue. Therefore, they are superior in the induction of cytotoxic T lymphocytes and the inhibition of tumor development and metastasis than bone marrow-derived DCs. This study established a novel approach to the treatment of preestablished solid and metastatic tumors using MIP-1α-recruited DCs transduced with tumor antigen gene.

Aquaporins in tumor growth and angiogenesis - Corrected Proof

Beatrice Nico, Domenico Ribatti — 2010-03-03

Abstract: The aquaporins (AQPs) are a family of transmembrane water channel proteins widely distributed and play a major role in transcellular and transepithelial water movement. Moreover, recent evidence indicates that AQPs may be involved in cell migration and angiogenesis. This review article summarizes literature data concerning the involvement of AQPs in tumor growth, angiogenesis and metastatic process and suggest a potential therapeutic approach by antagonizing their biological activity.

TWEAK/Fn14 promotes apoptosis of human endometrial cancer cells via caspase pathway - Corrected Proof

Dengfeng Wang, Jenny Nga Ting Fung, Ya Tuo, Lina Hu, Chen Chen — 2010-03-02

Abstract: Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible immediate-early response protein 14 (Fn14) have been detected in several human tumors, and demonstrated to regulate multiple cellular responses, including proliferation, survival, migration, apoptosis and differentiation, suggesting roles in cancer. The objective of this study was to clarify the role of TWEAK/Fn14 in the development of human endometrial cancer. We found that TWEAK gene expression was down-regulated and Fn14 gene expression was up-regulated in human endometrial cancer specimens compared with that in normal endometrial specimens; TWEAK acting on Fn14 decreased cell viability by inducing apoptosis through caspase pathways in endometrial cancer cells. Our results suggest that Fn14 expression is high in endometrial cancers whereas local produced TWEAK may be low. TWEAK/Fn14 pathway activation may promote cancer cell apoptosis, which provides a new therapeutic target for human endometrial cancer treatment.

Transcriptome of normal lung distinguishes mouse lines with different susceptibility to inflammation and to lung tumorigenesis - Corrected Proof

2010-03-02

Abstract: AIRmax and AIRmin mouse lines show a differential lung inflammatory response and differential lung tumor susceptibility after urethane treatment. The transcript profile of ∼24,000 known genes was analyzed in normal lung tissue of untreated and urethane-treated AIRmax and AIRmin mice. In lungs of untreated mice, inflammation-associated genes involved in pathways such as “leukocyte transendothelial migration”, “cell adhesion” and “tight junctions” were differentially expressed. Moreover, gene expression levels differed significantly in urethane-treated mice; in AIRmin mice, modulation of expression of genes involved in pathways associated with inflammatory response paralleled the previously observed persistent infiltration of inflammatory cells in the lung of these mice.

Multiple molecular mechanisms underlying trastuzumab and lapatinib resistance in JIMT-1 breast cancer cells - Corrected Proof

2010-03-02

Abstract: Trastuzumab plays an important role in breast cancer therapy. However, a significant fraction of patients do not respond to therapy or they tend to develop resistance shortly after beginning therapy. Although some resistance mechanisms have been described, it is unclear whether these mechanisms can coexist. In this study, we analyzed the resistance mechanisms in the breast cancer cell line JIMT-1, a model of intrinsic trastuzumab resistance. We compared the JIMT-1 cell line with a panel of eight HER-2 positive breast cancer cell lines. All cell lines were characterized for the phosphatidylinositol 3-kinase (PIK3CA) mutation status, expression levels of the phosphatase and tensin homolog on chromosome 10 (PTEN) and neuregulin-1 (NRG1) mRNA, HER-2 gene copy number, and protein expression. The results were correlated to the sensitivity to trastuzumab and lapatinib as well as the potency of trastuzumab-mediated antibody-dependent cellular cytotoxicity (ADCC) evoked by trastuzumab. JIMT-1 cells showed several co-existing drug resistance mechanisms, including an activating mutation of the PIK3CA gene, low expression of PTEN, high expression of NRG1, and relatively low expression of HER-2 receptor protein (despite gene amplification). All these features were present at variable levels in other cell lines, whereas JIMT-1 was unique in displaying all these factors at the same time. Unexpectedly, ADCC reaction by normal lymphocytes was equally strong in all HER-2 positive cell lines, without any correlation to molecular markers or direct sensitivity to the drugs. Resistance to trastuzumab and lapatinib is probably caused by several co-existing molecular mechanisms. Direct sensitivity to trastuzumab and lapatinib was not correlated with ADCC.

Enhanced anti-tumor activity by the combination of a conditionally replicating adenovirus mediated interleukin-24 and dacarbazine against melanoma cells via induction of apoptosis - Corrected Proof

2010-03-02

Abstract: Malignant melanoma is one of the most lethal and aggressive human malignancies. It is notoriously resistant to all of the current therapeutic modalities, including chemotherapy. Suppressed apoptosis and extraordinary invasiveness are the distinctive features that contribute to the malignancy of melanoma. Dacarbazine (DTIC) has been considered as the gold standard for melanoma treatment with a response rate of 15–20%. Unfortunately, the resistance to this chemotherapeutic agent occurs frequently. ZD55-IL-24 is a selective conditionally replicating adenovirus that can mediate the expression of interleukin-24 (IL-24) gene, which has a strong anti-tumor effect. In this study, we hypothesized that a combination of ZD55-IL-24-mediated gene virotherapy and chemotherapy using DTIC would produce an increased cytotoxicity against human melanoma cells in comparison with these agents alone. Our results showed that the combination of ZD55-IL-24 and DTIC significantly enhanced the anti-tumor activity by more effectively inducing apoptosis in melanoma cells than either agent used alone without any overlapping toxicity against normal cells. This additive or synergistic effect of ZD55-IL-24 in combination with DTIC in killing human malignant melanoma cells implies a promising novel approach for melanoma therapy.

Bee venom inhibits tumor angiogenesis and metastasis by inhibiting tyrosine phosphorylation of VEGFR-2 in LLC-tumor-bearing mice - Corrected Proof

2010-02-26

Abstract: Bee venom (BV) treatment is the therapeutic application of honeybee venom (HBV) for treating various diseases in Oriental medicine. In the present work, the authors investigated the functional specificity of BV as an angiogenesis inhibitor using in vitro models and in vivo mouse angiogenesis and lung metastasis models. BV significantly inhibited the viability of Lewis lung carcinoma (LLC) cells but did not affect peripheral blood mononuclear lymphocytes (PBML) cells. BV also inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). Western blotting analysis showed that BV inhibited AKT and MAPK phosphorylation in LLC cells and HUVECs and down regulated expression of VEGF and VEGFR-2 of LLC cells and HUVECs. Also, BV effectively disrupted VEGF-induced neovascularization in Matrigel plugs in our in vivo angiogenesis assay. When given subcutaneously, BV also significantly suppressed tumor angiogenesis through inhibition of VEGF and VEGFR-2 in LLC model. Mice bearing subcutaneous LLC tumors were treated with 1μg/ml or 10μg/ml of BV. They showed reductions ranging between 49% and 62% in primary tumor volume and reduction of spontaneous pulmonary metastasis occurrences. Furthermore, BV treatment in the spontaneous lung metastases model after primary tumor excision prolonged their median survival time from 27 to 58days. These results suggest that the tumor-specific anti-angiogenic activity of BV takes effect during different stages of tumor progression by blocking the tyrosine phosphorylation of VEGFR-2, and validate the application of BV in lung cancer treatment.

Platelet derived growth factor increases phospholipase D1 but not phospholipase D2 expression via NFκB signaling pathway and enhances invasion of breast cancer cells - Corrected Proof

Dong Woo Kang, Do Sik Min — 2010-02-26

Abstract: Phospholipase D (PLD) has emerged as a critical element in the cell growth signaling. Despite extensive information regarding the regulation of PLD activity in cell survival, the signaling mechanisms that regulate PLD expression in cancer remains poorly understood. Here we investigate that platelet derived growth factor (PDGF) increases PLD1 but not PLD2 expression via Ras–ERK/PI3K–NFκB signaling cascade in SK-BR3 breast cancer cells. The two NFκB-binding sites are functionally critical for transcriptional activation of PLD1 induced by PDGF. Furthermore, depletion of PLD1 using siRNA significantly abolished PDGF-induced upregulation of matrix metalloproteinase-2 or -9 and invasion of breast cancer cells. Thus, we propose that PDGF-induced PLD1 expression via NFκB signaling pathway might contribute to carcinogenesis.

Biomarkers of chemotherapy resistance in breast cancer identified by proteomics: Current status - Corrected Proof

2010-02-22

Abstract: This review describes and discusses the advantages and limitations of proteomic approaches in the identification of biomarkers associated with chemotherapy resistance. Both gel-based (two-dimensional polyacrylamide gel electrophoresis) and gel-free (shotgun and quantitative) mass spectrometry approaches are discussed. Non-mass spectrometry approaches including antibody microarray platforms are described as complementary proteomic strategies. Methods for technical confirmation and clinical validation of putative biomarkers are presented. Use of this proteomic toolbox in the quest for biomarkers of chemotherapy resistance in breast cancer is reviewed. Technical aspects of sample selection, acquisition, storage and analysis are discussed and putative biomarkers identified through proteomic approaches are presented.

Circulating tumor cells in metastatic colorectal cancer: Efficacy and feasibility of different enrichment methods - Corrected Proof

2010-02-18

Abstract: Comprehensive in vitro and in vivo studies comparing EpCAM-based methods with other cytometric CTC enrichment technologies in metastatic colorectal cancer (mCRC) patients are lacking. We compare four manual cytometric methods to detect CTCs in vitro and in mCRC patients. The EpCAM-based technology, MACS HEA MicroBeads®, showed a significant better tumor cell recovery rate compared to other cytometric methods (p-value<0.0001). CTCs of 38 mCRC patients were enriched with MACS HEA MicroBeads®. Progression-free survival did significantly differ between mCRC patients without detectable and with ⩾1 CTCs (p=0.007). CTC enrichment with EpCAM coupled antibodies is superior to other cytometric methods and is a feasible method for CTC detection in mCRC patients.

Gold(III) porphyrin 1a inhibited nasopharyngeal carcinoma metastasis in vivo and inhibited cell migration and invasion in vitro - Corrected Proof

2010-02-18

Abstract: A physiologically stable gold compound, gold(III) meso-tetraphenylporphyrin (gold-1a), has been shown to be effective in inducing apoptosis and prolonging the survival of hepatocellular carcinoma (HCC)-bearing rats as well as inhibiting the tumor growth of mice bearing nasopharyngeal carcinoma (NPC), neuroblastoma and colon carcinoma. In this study, we showed that gold-1a prolonged the survival of NPC metastasis-bearing mice and inhibited intrahepatic and lung metastasis. Histologically, gold-1a markedly reduced tumor microvessel formation. Consistently, in in vitro studies, gold-1a inhibited migration and invasion of C666-1 human NPC cells. The data strongly support the use of gold(III) compounds to treat cancer metastasis.

Combination with low-dose gemcitabine and hTERT-promoter-dependent conditionally replicative adenovirus enhances cytotoxicity through their crosstalk mechanisms in pancreatic cancer - Corrected Proof

2010-02-18

Abstract: To overcome the limited clinical efficacy of conditionally replicative adenoviruses (CRAds), we investigated the effects of combination therapy with gemcitabine (GEM) and the hTERT-promoter-dependent CRAd (hTERT-CRAd), Ad5/3hTERTE1. This combination therapy exhibited enhanced cytotoxic effects on pancreatic cancer both in vitro and in vivo. Furthermore, we revealed that this enhancement effect was due to the multiple bidirectional interactions between hTERT-CRAd and GEM. The GEM-sensitizing effect of E1 expression derived from hTERT-CRAd, and the enhancement effect by GEM on hTERT promoter activity which led to the increase of adenovirus E1 and viral infectivity. This combination therapy may be a promising therapeutic approach for pancreatic cancer.

Abrogation of Akt signaling by Isobavachalcone contributes to its anti-proliferative effects towards human cancer cells - Corrected Proof

2010-02-18

Abstract: Akt signaling pathway has attracted much attention as a promising target for cancer therapeutics. Herein, we report that Isobavachalcone (IBC), a natural chalcone, potently abrogates Akt signaling and exerts anti-proliferative effects on several human cancer cell lines. Modeling results from the Sybyl/FlexiDock program suggest that IBC potentially binds to the ATP-binding pocket of Akt, which is confirmed by the observations that IBC inhibits Akt1 kinase in vitro. Further studies reveal that IBC significantly abates Akt phosphorylation at Ser-473 and Akt kinase activity in cells, which subsequently leads to inhibition of Akt downstream substrates and evokes significant levels of apoptosis associated with mitochondria pathway.

CYP1A1 and CYP1B1 gene expression and DNA adduct formation in normal human mammary epithelial cells exposed to benzo[a]pyrene in the absence or presence of chlorophyllin - Corrected Proof

2010-02-17

Abstract: Benzo[a]pyrene (BP) is a potent pro-carcinogen and ubiquitous environmental pollutant. Here, we examined the induction and modulation of CYP1A1 and CYP1B1 and 10-(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPdG) adduct formation in DNA from 20 primary normal human mammary epithelial cell (NHMEC) strains exposed to BP (4μM) in the absence or presence of chlorophyllin (5μM). Real-time polymerase chain reaction (RT-PCR) analysis revealed strong induction of both CYP1A1 and CYP1B1 by BP, with high levels of inter-individual variability. Variable BPdG formation was found in all strains by r7, t8-dihydroxy-t-9, 10 epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)-DNA chemiluminescence assay (CIA). Chlorophyllin mitigated BP-induced CYP1A1 and CYP1B1 gene expression in all 20 strains when administered with BP. Chlorophyllin, administered prior to BP-exposure, mitigated CYP1A1 expression in 18/20 NHMEC strains (p<0.005) and CYP1B1 expression in 17/20 NHMEC strains (p<0.005). Maximum percent reductions of CYP1A1 and CYP1B1 gene expression and BPdG adduct formation were observed when cells were pre-dosed with chlorophyllin followed by administration of the carcinogen with chlorophyllin (p<0.005 for CYP1A1 and CYP1B1 expression and p<0.0005 for BPdG adducts). Therefore, chlorophyllin is likely to be a good chemoprotective agent for a large proportion of the human population.

Annexin-1 protects MCF7 breast cancer cells against heat-induced growth arrest and DNA damage - Corrected Proof

Sunitha Nair, M. Prakash Hande, Lina H.K. Lim — 2010-02-17

Abstract: Stress proteins protect cells against the effects of heat stress, such as cell death and DNA damage. We wished to determine if Annexin-1 (ANXA1) could mediate heat-induced growth arrest and DNA damage in MCF7 breast cancer cells. Heat induced a significant growth arrest at 4h–24h. Growth arrest and heat-induced DNA damage were significantly inhibited in MCF7 cells over-expressing ANXA1. These effects were associated with enhanced ERK activation and reduction in JNK phosphorylation. This study demonstrates that ANXA1, which we recently reported as a possible tumor suppressor gene, can protect cells from heat-induced growth arrest and DNA damage.

Targeted cytotoxic somatostatin analog AN-162 inhibits growth of human colon carcinomas and increases sensitivity of doxorubicin resistant murine leukemia cells - Corrected Proof

2010-02-16

Abstract: The effect of the targeted cytotoxic somatostatin (SST) analog AN-162, consisting of doxorubicin (DOX) conjugated to SST carrier RC-121, was investigated on the growth of human colorectal cancer (CRC) cell lines HT-29, HCT-15, and HCT-116 and a DOX-resistant mouse leukemia cell line P388/R84. mRNA for SST-receptors and high affinity binding sites for SST were detected in all CRC cell lines and in P388/R84 cells. In contrast to DOX alone, AN-162 blocked HCT-116 cells and P388/R84 cells in S/G2 phase and increased the number of apoptotic cells. In vivo, AN-162 reduced the volume of CRC xenografts more effectively than its unconjugated components. Our results suggest that AN-162 inhibits growth of experimental CRC more effectively than DOX and increases sensitivity of DOX resistant human leukemia cells.

The BH3-mimetic GX15-070 induces autophagy, potentiates the cytotoxicity of carboplatin and 5-fluorouracil in esophageal carcinoma cells - Corrected Proof

Jingxuan Pan, Chao Cheng, Srdan Verstovsek, Qi Chen, Yanli Jin, Qi Cao — 2010-02-15

Abstract: Despite improvements in both surgical techniques and radio- and chemo-therapy regimens, the prognosis of esophageal cancer is poor. In pursuit of novel effective strategy, this study examined the effect of the BH3-mimetic GX15-070 on esophageal carcinoma cells. We discovered that GX15-070 inhibited the growth of esophageal cancer cells. There was synergism between GX15-070 and carboplatin or 5-fluorouracil. GX15-070 induced autophagy in esophagus cancer cell line EC9706 and osteosarcoma cancer cell line U2OS. 3-methyladenine and chloroquine, inhibitors of autophagy with distinct mechanisms, potentiated the cytotoxicity of GX15-070. In conclusion, GX15-070 inhibits growth of esophageal cancer cells.

Fusicoccin-A selectively induces apoptosis in tumor cells after interferon-α priming - Corrected Proof

2010-02-15

Abstract: Active small molecules have a high potential for the development into new anti-cancer drugs. Here we analysed the effect of the natural occurring fusicoccanes, Fusicoccin-A (FC), Ophiobolin-A (OPH-A) and Ophiobolin-I (OPH-I) on various tumor cell lines. Both FC and OPH-A inhibit tumor cell growth efficiently, in contrast to OPH-I. Further analysis showed that FC is tumor specific, and that its efficacy can be enhanced by combining it with the cytokine interferon-α (IFN-α). In this, IFN-α primes the tumor cells for apoptosis induction by FC, in which DR4 and the TRAIL pathway plays an important role. Healthy cells (HUVECs, Human Umbilical Vein Endothelial Cells) are far less sensitive to IFN-α/FC treatment and need the continuous presence of both compounds in order to achieve a growth reduction. This differential response between healthy and tumor cells indicates that the IFN-α/FC treatment is a promising new cancer treatment, especially when IFN-α and FC are used sequentially.

MYCN oncoprotein targets and their therapeutic potential - Corrected Proof

2010-02-15

Abstract: The MYCN oncogene encodes a transcription factor which is amplified in up to 40% of high risk neuroblastomas. MYCN amplification is a well-established poor prognostic marker in neuroblastoma, however the role of MYCN expression and the mechanisms by which it acts to promote an aggressive phenotype remain largely unknown. This review discusses the current evidence identifying the direct and indirect downstream transcriptional targets of MYCN from recent studies, with particular reference to how MYCN affects the cell cycle, DNA damage response, differentiation and apoptosis in neuroblastoma.

Reproductive fitness advantage of BCR–ABL expressing leukemia cells - Corrected Proof

Arne Traulsen, Jorge M. Pacheco, David Dingli — 2010-02-15

Abstract: Mutations in oncogenes and tumor suppressor genes confer a fitness advantage to cells that can lead to cancer. The tumor phenotype normally results from the interaction of many mutant genes making it difficult to estimate the fitness advantage provided by any oncogene, except when tumors depend on one oncogene only. We utilize a model of chronic myeloid leukemia (CML), to quantitate the fitness advantage conferred by expression of BCR–ABL in hematopoietic cells from in vivo patient data. We show that BCR–ABL expression provides a high fitness advantage, which explains why this single mutation drives the chronic phase of CML.

Inhibition of the transcriptional function of p53 by EWS–Fli1 chimeric protein in Ewing Family Tumors - Corrected Proof

2010-02-15

Abstract: The chromosomal translocation t(11;22)(q24;q12) generates the EWS–Fli1 fusion gene, which contributes to the development of Ewing Family Tumors (EFTs). Although p53 mutations are found only in 5–20% of EFTs, the p53 pathway is thought to be abrogated in EFTs. The role of EWS–Fli1 in the p53 pathway in the tumor is still poorly understood. In this study, using immunoprecipitation and co-localization, we show that EWS–Fli1 interacts with p53 within the nucleus in vivo. The introduction of EWS–Fli1 resulted in significant reduction of promoter activities and mRNA levels of p21 and mdm2, meanwhile it canceled p53-dependent growth suppression. In contrast, knockdown of EWS–Fli1 expression mediated by small interfering RNAs (siRNA) also augmented the induction of p21 and mdm2 in response to DNA damage. Furthermore, using serial deletion constructs of the EWS–Fli1 fusion protein, we determined that EWS–Fli1 binding to p53 as well as inhibition of p21 and mdm2 promoter activities was mediated by its N-terminal domain (amino acid residues 65–109). These observations suggest that the N-terminal region of EWS–Fli1 might associate with p53 and impair its transcriptional activity, subsequently inhibiting the expression of its downstream genes. These results might provide new insight into the oncogenesis of EFTs by EWS–Fli1 via the inhibition of p53 function.

The ubiquitin–proteasome system is inhibited by p53 protein expression in human ovarian cancer cells - Corrected Proof

In Young Hwang, Bruce C. Baguley, Lai-Ming Ching, Catherine A. Gilchrist — 2010-02-15

Abstract: The ubiquitin–proteasome system (UPS) and autophagy provide major cellular pathways for protein degradation. Since the p53 pathway controls autophagy, we investigated whether p53 regulates UPS in ovarian tumour cell lines. A reporter cell line (SKOV3-EGFPu) was established to measure UPS function against a constant genetic background. Transient expression of either wild type or mutant p53 in SKOV3-EGFPu cells reduced UPS activity as compared to vector control. These results, together with those from endogenous p53 expression in seven ovarian cancer cell lines, suggest that expression of both wild-type and mutant p53 protein impairs UPS function. Thus, p53 expression may regulate protein homeostasis by down-regulating UPS function in response to cellular stress.

EGFR and EGFRvIII interact with PUMA to inhibit mitochondrial translocalization of PUMA and PUMA-mediated apoptosis independent of EGFR kinase activity - Corrected Proof

Hu Zhu, Xinyu Cao, Francis Ali-Osman, Stephen Keir, Hui-Wen Lo — 2010-02-15

Abstract: EGFR and its constitutively activated variant EGFRvIII are linked to glioblastoma resistance to therapy, the mechanisms underlying this association, however, are still unclear. We report that in glioblastoma, EGFR/EGFRvIII paradoxically co-expresses with p53-upregulated modulator of apoptosis (PUMA), a proapoptotic member of the Bcl-2 family of proteins primarily located on the mitochondria. EGFR/EGFRvIII binds to PUMA constitutively and under apoptotic stress, and subsequently sequesters PUMA in the cytoplasm. The EGFR–PUMA interaction is independent of EGFR activation and is sustained under EGFR inhibition. A Bcl-2/Bcl-xL inhibitor that mimics PUMA activity sensitizes EGFR/EGFRvIII-expressing glioblastoma cells to Iressa. Collectively, we uncovered a novel kinase-independent function of EGFR/EGFRvIII that leads to tumor drug resistance.

The establishment of a new mouse model with orthotopic esophageal cancer showing the esophageal stricture - Corrected Proof

2010-02-12

Abstract: We established a promising new experimental animal model with an orthotopic xenograft of esophageal cancer that successfully represents poor oral intake, a major clinical feature of esophageal cancer. The advantage of this model is that no surgical technique is required, only the injection of a cell suspension by a needle and syringe via the esophageal lumen from the mouth, which provides a high reproducibility of tumor implantation and a rapid progress of outcome. We propose that this model is useful to study cancer-related outcomes and for developing new therapies for esophageal cancer, and we expect it to make a contribution to clinical practice.

Cucurbitacin B induces apoptosis and S phase cell cycle arrest in BEL-7402 human hepatocellular carcinoma cells and is effective via oral administration - Corrected Proof

2010-02-12

Abstract: Cucurbitacin B is an anti-cancer drug candidate and its efficacy has been demonstrated in hepatocellular carcinoma (HCC). To explore its mechanism against HCC, BEL-7402 cells were treated with cucurbitacin B in vitro. Treatment with cucurbitacin B induced S phase arrest and apoptosis. The growth inhibition effect was associated with cyclin D1 and cdc-2 down regulations. Western blotting analysis of cell signaling molecules indicated that cucurbitacin B inhibited c-Raf activation without affecting STAT3 phosphorylation. Moreover, in vivo study demonstrated that cucurbitacin B is effective against BEL-7402 xenograft when administrated orally.

Alpha-fetoprotein producing cells act as cancer progenitor cells in human cholangiocarcinoma - Corrected Proof

2010-02-11

Abstract: We aimed to demonstrate that alpha-fetoprotein (AFP)-producing cells in cholangiocarcinomas possessed cancer stem cell (CSC)-like properties. AFP enhancer/promoter-driven EGFP gene was transfected into human cholangiocarcinoma cell lines. One cell line, RBE, expressed both AFP and EGFP. Clonal analyses revealed that one EGFP-positive cell generated both EGFP-positive and EGFP-negative cell fractions. However, one EGFP-negative cell never produced EGFP-positive cells. The EGFP-positive cells had a greater tumorigenic potential. Only the EGFP-positive cells expressed Notch1. AFP and Notch1 expression was observed in clinical intrahepatic cholangiocarcinomas. The AFP-producing cells were suggested to be CSCs. The Notch pathway might play an important role in maintaining the CSC characteristics.

Anti-tumor immune response induced by dendritic cells transduced with truncated PSMA IRES 4-1BBL recombinant adenoviruses - Corrected Proof

2010-02-10

Abstract: Up-regulation of receptor–ligand pairs during interaction of a peptide-bound MHC complex on dendritic cells (DCs) with cognate TCR may amplify, sustain, and drive diversity in the ensuing T cell immune response. Members of the TNF ligand superfamily and the TNFR superfamily contribute to this costimulatory molecule signaling. In the present study, we used replication deficient adenoviruses to introduce a tumor-associated Ag (a truncated human prostate-specific membrane antigen (tPSMA)) and the T cell costimulatory molecule 4-1BBL into murine DCs, and observed the ability of these recombinant DCs to elicit tPSMA-directed T-cell responses in vitro and anti-tumor immunity to RM-1-tPSMA in a murine tumor model. Infection of DCs with Ad-tPSMA-IRES-m4-1BBL induced tPSMA-specific proliferative responses and up-regulated CD80 and CD86 s signaling molecules. The cytotoxic T lymphocytes activated by the Ad-tPSMA-IRES-m4-1BBL-transfected DCs showed significantly higher IFN-γ production and cytotoxicity against the RM-1 cells transfected with tPSMA. Moreover, vaccination of mice with Ad-tPSMA-IRES-m4-1BBL-transfected DCs induced a potent protective and therapeutic anti-tumor immunity to RM-1-tPSMA in a tumor model. These results demonstrated that development of DCs engineered to express tPSMA and 4-1BBL by recombinant adenovirus-mediated gene transfer may offer a new strategy for prostate cancer immunotherapy.

Overexpression of c-myc induces epithelial mesenchymal transition in mammary epithelial cells - Corrected Proof

Kyoung Bin Cho, Min Kyong Cho, Won Young Lee, Keon Wook Kang — 2010-02-10

Abstract: The c-myc gene is frequently overexpressed in human breast cancer and its target genes are involved in tumorigenesis. Epithelial mesenchymal transitions (EMT), where cells undergo a developmental switch from a polarized epithelial phenotype to a highly motile mesenchymal phenotype, are associated with invasion and motility of cancer cells. Basal E-cadherin expression was down-regulated in c-myc overexpressing MCF10A (c-myc-MCF10A) cells compared to GFP-overexpressing MCF10A (GFP-MCF10A) cells, while N-cadherin was distinctly increased in c-myc-MCF10A cells. Given that glycogen synthase kinase-3β (GSK-3β) and the snail axis have key roles in E-cadherin deregulation during EMT, we investigated the role of GSK-3β/snail signaling pathways in the induction of EMT by c-myc overexpression. In contrast to GFP-MCF10A cells, both the transcriptional activity and the ubiquitination-dependent protein stability of snail were enhanced in c-myc-MCF10A cells, and this was reversed by GSK-3β overexpression. We also found that c-myc overexpression inhibits GSK-3β activity through activation of extracellular signal-regulated kinase (ERK). Inhibition of ERK by dominant negative mutant transfection or chemical inhibitor significantly suppressed snail gene transcription. These results suggest that c-myc overexpression during transformation of mammary epithelial cells (MEC) is involved in EMTs via ERK-dependent GSK-3β inactivation and subsequent snail activation.

Lentiviral shRNA screen of human kinases identifies PLK1 as a potential therapeutic target for osteosarcoma - Corrected Proof

2010-02-10

Abstract: We describe an optimized systematic screen of known kinases using osteosarcoma cell lines (KHOS and U-2OS) and a lentiviral-based short hairpin RNA (shRNA) human kinase library. CellTiter 96®AQueous One Solution Cell Proliferation Assay was used to measure cell growth and survival. We identified several kinases, including human polo-like kinase (PLK1), which inhibit cell growth and induce apoptosis in osteosarcoma cells when knocked down. cDNA rescue and synthetic siRNA assays confirm that the observed phenotypic changes result from the loss of PLK1 gene expression.Furthermore, a small molecule inhibitor to PLK1 inhibited osteosarcoma cell growth and induced apoptosis. Western blot analysis confirmed that PLK1 is highly expressed and activated in several osteosarcoma cell lines as well as in resected tumor samples. Immunohistochemistry analysis showed that patients with high PLK1 tumor expression levels correlated with significantly shorter survival than patients with lower levels of tumor PLK1 expression. These results demonstrate the capability and feasibility of a high-throughput screen with a large collection of lentiviral kinases and its effectiveness in identifying potential drug targets. The development of more potent inhibitors that target PLK1 may open doors to a new range of anti-cancer strategies in osteosarcoma.

Captopril and S-nitrosocaptopril as potent radiosensitizers: Comparative study and underlying mechanisms - Corrected Proof

2010-02-10

Abstract: In an effort to improve the issue of radiotherapy treatments, we tested whether S-nitrosocaptopril, a molecule combining a NO donor and an angiotensin converting enzyme inhibitor (ACE inhibitor), could temporarily improve the hemodynamic status of experimental tumors. We monitored the effect of S-nitrosocaptopril in TLT tumors using non rinvasive magnetic resonance techniques. We identified a time window during which tumor oxygenation was improved, as a result of a combined effect on tumor blood flow and oxygen consumption. Consequently, the administration of S-nitrosocaptopril contributed to the increase in efficacy of radiation therapy, an effect that was not observed with captopril alone.

TP53, EGFR, and KRAS mutations in relation to VHL inactivation and lifestyle risk factors in renal-cell carcinoma from central and eastern Europe - Corrected Proof

2010-02-08

Abstract: Renal-cell carcinomas (RCC) are frequent in central and eastern Europe and the reasons remain unclear. Molecular mechanisms, except for VHL, have not been much investigated. We analysed 361 RCCs (334 clear-cell carcinomas) from a multi-centre case-control study for mutations in TP53 (exons 5–9 in the whole series and exons 4 and 10 in a pilot subset of 60 tumours) and a pilot 50 tumours for mutations in EGFR (exons 18–21) or KRAS (codon 12) in relation to VHL status. TP53 mutations were detected in 4% of clear-cell cases, independently of VHL mutations. In non-clear-cell carcinomas, they were detected in 11% of VHL-wild-type tumours and in 0% of tumours with VHL functional mutations. No mutations were found in EGFR or KRAS. We conclude that mutations in TP53, KRAS, or EGFR are not major contributors to the RCC development even in the absence of VHL inactivation. The prevalence of TP53 mutations in relation to VHL status may differ between clear-cell and other renal carcinomas.

Synergistic antitumor effect of TRAIL in combination with sunitinib in vitro and in vivo - Corrected Proof

2010-02-08

Abstract: The present data showed that sunitinib potentiated the in vitro and in vivo anticancer capabilities of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), also known as Apo2 ligand. Interactions between sunitinib and TRAIL were examined in colon cancer SW620 cells and lung cancer 95-D cells. The average combination index (CI) values of the anti-proliferation abilities on each cancer cell line were less than 1.0, demonstrating the synergism of the combination of sunitinib and TRAIL. Western blot experiments indicated that TRAIL and sunitinib synergistically enhanced apoptosis by simultaneously activating the extrinsic and intrinsic pathways. The decrease in the expression levels of anti-apoptotic proteins cFLIP, XIAP and Mcl-1 were probably involved in this apoptosis enhancement. Furthermore, treatment of colon cancer SW620-bearing nude mice with sunitinib plus TRAIL resulted in more significant tumor growth inhibition (52.8%), comparing with the moderate inhibition in TRAIL-treated (35.3%) or sunitinib-treated groups (26.7%) (p<0.05). These results indicate that the combination of TRAIL with sunitinib seems highly encouraging and warrants further investigation in a clinical setting.

Phosphorylated c-Jun NH2-terminal kinase is overexpressed in human papillary thyroid carcinomas and associates with lymph node metastasis - Corrected Proof

Xiao Wang, Lan Chao, Junhui Zhen, Liansheng Chen, Guohui Ma, Xin Li — 2010-02-08

Abstract: To evaluate the associations of phosphorylated c-Jun NH2-terminal kinase (p-JNK) expression with clinicopathological features in patients with papillary thyroid carcinoma, p-JNK expression were immunohistochemically measured in 121 thyroid samples. p-JNK was overexpressed in papillary thyroid carcinomas with respect to matched nontumorous tissues (P=0.000), which was supported by western blot analysis. Increased p-JNK expression was significantly associated with the presence of lymph node metastases (P=0.001) and advanced TNM stages (P=0.02). Furthermore, p-JNK expression was positively correlated with osteopontin (OPN) expression (r=0.58, P<0.001). Activation of p-JNK may play a role in the carcinogenesis and lymph node metastasis of papillary thyroid carcinoma, and may be a molecular target for therapeutic intervention.