bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2546: IGR-1R pathway role in oxaliplatin acquired resistance in colon cancer cell lines and its regulation by MMP-7 and IGFBP-2
Authors: Codony-Servat Jordi , Martínez-Cardús Anna , Marín-Aguilera Mercedes , García-Albéniz Xabier , Augé Josep Maria , Gallego Rosa , Pineda Estela , Ginés Alba , Abad Albert , Gascón Pere , Martínez-Balibrea Eva , Maurel Joan
Published: February 2011

Background: IGF-1R pathway and MMPs have been implicated in chemotherapy resistance in colorectal cancer. This receptor could be activated by IGF1 or IGF2 ligands, which bioavailability is regulated by IGFBPs, what could be degraded by MMPs. Objectives: To determine the basal levels and the modulation by chemotherapy (oxaliplatin), of the levels of IGF-1R, IGFBPs and MMPs in colon cancer cell lines (HT-29 (IC50: 6,46 uM) and LoVo (IC50: 0,25 uM) and their oxaliplatin resistant cell lines (HT-29OXAR3 (IC50: 29,86 uM) and LoVOXAR3 (2,45 uM)). To analyze the differences in apoptosis between parental and oxaliplatin resistant cell lines when are treated with oxaliplatin. Methods: MMP-7 levels were analyzed by RT-PCR, Western Blot and ELISA. Levels of IGF-1R, activated IGF-1R, IGFBP-2, and IGFBP-3 were determined by Western Blot and/or ELISA. Differences in cell viability were analyzed by MTT, and intrinsic (bcl-2, bax) and extrinsic (Fas, caspase 8) apoptotic pathways, by Western Blot, in parental and oxaliplatin resistant cell lines with dose-response experiments. Results: LoVo and LoVOXAR3 express low levels of MMP-7 and IGF-1R and high levels of IGFBP-2 compared with HT-29 and HT-29OXAR3. In addition, HT-29OXAR3 cells showed increased MMP-7, IGF-1R and pIGF-1R levels compared with HT-29 and lower levels of IGFBP-2. We also observed after oxaliplatin treatment in HT-29 cells a decrement of IGF-1R and IGFBP-2 and an increment in MMP-7 levels. In apoptotic experiments, FAS and caspase 8 (extrinsic pathway) were induced by oxaliplatin in LOVO (0.2 uM) and in LOVOXAR3 (20uM). Bcl-2 and bax (intrinsic pathway) were induced or decremented respectively in LOVO (2uM) and LOVOXAR3 (20uM). No changes in these extrinsic apoptotic proteins were observed in HT29 and HT29OXR3. In HT-29OXAR3 cell line higher doses of oxaliplatin (20 uM instead of 2uM) were needed to induce intrinsic apoptotic (bax) and antiapoptotic proteins (bcl-2) Conclusions: IGF-1R signalling is implicated in acquired oxaliplatin resistance and it is regulated by MMP-7 and IGFBP-2 in a different manner in our two models of cancer colon cell lines. The two apoptotic pathways were implicated in LoVo cell lines, but only intrinsic pathway regulates apoptosis in HT-29 cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2546.
Abstract 2552: Loss of MiTF sensitizes melanoma cells to chemotherapy due in part to reduced LAMP1 accumulation
Authors: Liu Feng , Hwe Christopher , Chu Raymond , Meyskens Frank
Published: February 2011

MiTF (microphthalmia-associated transcription factor) was reported to be amplified in about 20% of melanoma samples and has an oncogenic property. However it is also known that in a subset of melanoma cell lines and tissues MiTF accumulation level is much reduced as compared to normal human melanocytes. Here we confirmed this observation in both melanoma cell lines and tissues. We found that MiTF accumulation level was independent of BRAF mutations status. Loss of MiTF was found at both mRNA and protein levels in melanoma cell lines. Interestingly, melanoma cell lines with MiTF accumulation showed higher resistance to multiple drug treatment. Further investigation revealed that lysosomal-associated membrane protein 1 (LAMP1) levels are tightly associated with MiTF accumulation and is a direct downstream transcription target for MiTF. Over-expression of LAMP1 in melanoma cells conferred drug resistance while knock-down LAMP1 by shRNA sensitized melanoma cells to chemotherapy drugs. Our studies revealed a novel transcription target for MiTF and a novel drug resistance mechanism that is mediated by MiTF, which may be associated with their intrinsic exocytosis function of melanoma cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2552.
Abstract 2555: Class I β-tubulin mutations induce resistance to microtubule destabilizer through stabilization of the microtubule networks
Authors: Cheung Chun Hei Antonio , Wu Su-Ying , Chang Chi-Yen , Hsieh Hsing-Pang , Chang Jang-Yang
Published: February 2011

Anti-mitotic compounds such as vincristine, colchicine and paclitaxel have been developed to target microtubules in cancers. Although these compounds have been shown successful in treating various cancers, development of drug-resistance cells limits their efficacies in clinical situations. To determine possible mechanisms that are responsible for drug-resistance to microtubule de-stabilizers, KB-derived drug-resistant KB-L30 cells were developed. KB-L30 cells showed resistance to various microtubule de-stabilizers through multiple-drug resistant (MDR)-independent mechanisms. In contrast, this specific clone showed hyper-sensitized to the microtubule-stabilizer, paclitaxel. Single-strand conformation polymorphism (SSCP) analysis, RT-PCR and DNA sequencing revealed no mutation on exon 1, 2 and 3 of βI-tubulin. Surprisingly, six novel mutation sites were found present in the exon 4 of βI-tubulin gene. Transfection of the βI-tubulin-mutated construct into KB cells demonstrated that these mutations could alter its sensitivity to the microtubule de-stabilizer, BPR0L075, in vitro. On the other hand, western blot analysis revealed increased microtubule assembly and reduced microtubule dynamic instability in KB-L30 cells when compared to its parental KB cells. In addition, computational modeling indicated that a direct relationship exists between tubulin mutations and alteration in the microtubule assembly and dynamic instability in KB-L30 cells. In conclusion, we showed for the first time that mutations in exon 4 of βI-tubulin induced resistance to microtubule de-stabilizers and hyper-sensitivity to microtubule stabilizer through an alteration in the microtubule assembly and dynamics in cancer cells. The results of this study have important implications for the development of future anti-mitotic compounds that are able to target microtubule mutation-induced drug-resistant cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2555.
Abstract 2560: Cyclin-dependent kinase inhibitor SU9516 enhances sensitivity to methotrexate in human T-cell Jurkat cells
Authors: Uchiyama Hitoji , Sowa Yoshihiro , Wakada Miki , Yogosawa Mayumi , Nakanishi Ryoko , Horinaka Mano , Shimazaki Chihiro , Taniwaki Masafumi , Sakai Toshiyuki
Published: February 2011

Methotrexate (MTX), a classical anti-folate drug, has been used to treat various hematological malignancies. Since MTX prevents tumor cells from proliferating by inhibiting dihydrofolate reductase (DHFR), DHFR expression is a key determinant of resistance to MTX in malignant hematological tumor cells. In fact, it is well known that elevated expression of DHFR is a direct factor in clinical therapeutic resistance to MTX. First of all, we demonstrated that the sensitivity to MTX was enhanced by the knockdown of the DHFR gene in human T-cell leukemia cell. Concretely, the anti-proliferative effect of MTX was significantly enhanced by the knockdown of DHFR expression by siRNA in Jurkat cells. Therefore, a novel strategy down-regulating DHFR expression seems promising for enhancing sensitivity to MTX. On the other hand, the expression of DHFR is controlled by the transcription factor E2F. Unphosphorylated retinoblastoma (RB) protein is known to bind and inhibit the E2F. Cyclin-dependent kinase (CDK) inhibitors activate RB function and inhibit E2F function. Then we tested whether CDK inhibitor acted as a suppressor of DHFR through the E2F site of the promoter. We found that SU9516, a cyclin-dependent kinase inhibitor, decreased phospho-RB (Ser780) and reduced the expression of both DHFR mRNA and protein, and the DHFR promoter activity was attenuated by SU9516 dependent on the E2F site. Furthermore, pretreatment with SU9516 significantly enhanced sensitivity to MTX in a colony formation assay. To expand these results in Jurkat cells, we have also examined other leukemic cell lines (human T cell leukemia CCRF-CEM cells and human erythroleukemia K562 cells) and confirmed that SU9516 also repressed the levels of DHFR protein and phopho-RB (Ser780), and enhanced the cytotoxicity of MTX in a colony formation assay in both of cell lines. To expand these results by SU9516, we have examined other CDK inhibitors (Purvalanol A and Cdk4/6 Inhibitor IV) and confirmed that these agents also decreased DHFR protein and phospho-RB (Ser780), and enhanced the cytotoxicity of MTX in a colony formation assay in Jurkat cells as similar as SU9516. Based on these findings, we conclude that a combination of cyclin-dependent kinase inhibitors and MTX may be useful for overcoming resistance to MTX.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2560.
Abstract 2561: Genistein restored chemosensitivity to oxaliplatin in gemcitabine resistant pancreatic cancer cells in vitro and in orthotopic xenograft mouse model
Authors: Banerjee Sanjeev , Wang Zhiwei , Azmi Asfar , Kong Dejuan , Ahmad Aamir , Sarkar Fazlul H.
Published: February 2011

Chemotherapy remains the main stay for pancreatic cancer (PC) treatment with Gemcitabine showing modest benefit. Oxaliplatin has been used as a second line therapy in combination with gemcitabine but the beneficial effect was mitigated due to ‘off target’ toxicity as well as due to de novo and acquired resistance. However, effort toward restoration of sensitivity of PC cells to low concentrations of oxaliplatin is an emerging area of research. Here we report our in vitro and in vivo preclinical evidence in support of chemo-sensitization of gemcitabine resistant PC cells (Panc-1, Panc-28 and MiaPaCa-2) by a non-toxic chemopreventive agent known as genistein. Genistein pretreatment of PC cells exhibiting moderate (Panc-1, Panc-28) to less gemcitabine sensitivity (MiaPaCa-2) using low concentrations of oxaliplatin resulted in a significant reduction in the viability of cells concomitant with increased apoptosis (p<0.01) occurred in a synergistic manner as assessed by colony formation experiments. Since drug-resistance of PC is allegedly linked with constitutive activation of NF-κB as well as further activation by conventional chemotherapeutic agents including oxaliplatin, our mechanistic showed that inactivation of NF-κB by genistein prior to treatment of cell with oxaliplatin is required for the killing of drug resistant cells, which indeed was consistent with the down- regulation of NF-κB and its downstream anti-apoptotic genes (Bcl-2 XIAP's, survivin) leading to the appearance of cleaved PARP and induction of apoptosis. Most importantly, our in vivo experiments using orthotopic mouse model of pancreatic cancer showed significant reduction in tumor size (p<0.01) and reduction of locoregional lymph node metastasis when genistein was given in combination with oxaliplatin compared to monotherapy. These results were also consistent with inactivation of NF-κB and the down-regulation of NF-kB downstream targets (Bcl-xL, survivin and XIAP), all of which was consistent with in vitro findings. Both in vitro as well as in vivo findings were also consistent with immunohistochemistry findings on proliferation marker (Ki-67), apoptosis (TUNEL) and phospho p-65 immunostaining. From these results, we conclude that our results provide strong in vivo evidence in support of our hypothesis showing that genistein sensitizes drug-resistant pancreatic cancer to oxaliplatin, which is mechanistically linked with inactivation of NF-κB, which could be a useful strategy for the treatment of PC in the future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2561.
Abstract 2568: Acquired apoptosis resistance mediated by activation of the Akt/COX-2/Mcl-1 pathway in lung cancer cells
Authors: Chen Wenjie , Bai Lang , Wang Xia , Xu Shanling , Belinsky Steven A. , Lin Yong
Published: February 2011

Acquired apoptosis resistance plays an important role in acquired chemoresistance in cancer cells during chemotherapy. Based on our previous observations that acquired TNF-related apoptosis-inducing ligand (TRAIL)-resistance in lung cancer cells was associated with Akt-mediated stabilization of c-FLIP and Mcl-1, we further examined if the TRAIL-resistant cells also have acquired resistance to apoptosis induced by chemotherapeutics, such as cisplatin (CDDP) and adriamycin (Adr), and the mechanism underlying this resistance. By systematically delineating the signaling pathway for acquired apoptosis resistance using in vitro cell culture and in vivo xenografted tumor models, we determined that these TRAIL-resistant cells also have acquired resistance to apoptosis induced by chemotherapeutics such as cisplatin (CDDP) and adriamycin (Adr). We further found that COX-2 is dramatically overexpressed in cells with acquired apoptosis resistance. COX-2 appears to be a crucial mediator in acquired apoptosis resistance because suppressing COX-2 activity with chemical inhibitors or reducing COX-2 protein expression level with COX-2 siRNA dramatically alleviated resistance to therapeutic-induced apoptosis both in vitro and in vivo. Inhibiting Akt markedly reduced COX-2 expression, suggesting COX-2 is a downstream effector mediating apoptosis resistance of this cell survival kinase. Furthermore, the expression of Mcl-1 but not c-FLIP was significantly reduced when COX-2 was suppressed and knockdown of Mcl-1 substantially sensitized the cells to CDDP- or Adr-induced apoptosis. Our results establish a novel pathway that consists of Akt, COX-2, and Mcl-1 for acquired apoptosis resistance, which could be a molecular target for circumventing acquired chemoresistance in lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2568.
Abstract 2571: The predictive biomarker for the resistance to antifolate
Authors: Uemura Takehiro , Oguri Tetsuya , Ozasa Hiroaki , Takakuwa Osamu , Tomita Yuki , Nakao Makoto , Suzuki Takeshi , Iwashima Yasuhito , Miyazaki Mikinori , Maeno Ken , Sato Shigeki , Ueda Ryuzo
Published: February 2011

Currently, several folate-based antimetabolites are used for cancer treatment. Pemetrexed (MTA) is new generation antifolate which inhibits multiple folate-requiring enzymes, mainly thymidylate synthase (TS). We cultured small lung cell cancer cell line, PC-6 in the presence of MTA and established two MTA resistant cell lines, PC-6/MTA-1.6 and PC-6/MTA-4.0, which grew vigorously in medium containing 1.6uM and 4.0uM, respectively. These cell lines showed cross resistance to methotrexate (MTX), but not to other cytotoxic agents including etoposide, vinorelbine and cisplatin. Among many ATP-binding cassette (ABC) transporters, only ABCC11/MRP8 (ABCC11) gene expression was markedly increased in PC-6/MTA-1.6 cells. In contrast, TS gene expression was markedly increased in PC-6/MTA-4.0 cells. ABCC11 gene expression was not increased in PC-6/MTA-4.0 cells. There were no changes in reduced folate carrier and folylpoly-gamma-glutamate synthetase expression level in MTA resistant cells. To determine if the higher expression of the ABCC11 in the PC-6/MTA-1.6 cells resulted in a greater efflux of drugs, we assayed the intracellular accumulation of MTX, which is known to be a substrate for ABCC11 in the PC-6 and PC-6/MTA-1.6 cells and found that MTX accumulation in PC-6/MTA-1.6 cells was lower than PC-6 cells. We found that decrease of ABCC11 expression by ABCC11 siRNA enhanced MTA and MTX cytotoxicity in PC-6/MTA-1.6 cells. Decreasing the expression of TS by small interfering RNA (siRNA) also enhanced MTA and MTX cytotoxicity in PC-6/MTA-4.0 cells. These results give a concept that resistance for antifolate is advanced as TS gene expression is increased, while ABCC11 may work in early phase of resistance when TS expression is not enough induced. TS and ABCC11 may be useful as predictive biomarkers for the resistance to antifolate.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2571.
Abstract 2574: Development and characterization of a potent immunotoxin targeting the Fn14 receptor on solid tumor cells
Authors: Zhou Hong , Marks John W. , Winkles Jeffrey A. , Yagita Hideo , Rosenblum Michael G.
Published: February 2011

TNF-like weak inducer of apoptosis (TWEAK) and FGF-inducible 14 (Fn14) are a TNF superfamily ligand-receptor pair involved in inflammation, oncogenesis, tumor invasion, migration, survival and resistance to chemotherapy. The Fn14 receptor is expressed at relatively low levels in normal tissues, but is known to be dramatically elevated in a number of tumor types, including brain and breast tumors. Thus, the TWEAK/Fn14 axis appears to be an excellent candidate for therapeutic intervention. We have developed an immunoconjugate designated ITEM4-rGel containing a high-affinity anti-Fn14 monoclonal antibody conjugated to recombinant gelonin (rGel), a highly cytotoxic, ribosome-inactivating n-glycosidase. The ITEM4-rGel conjugate was generated and purified and contained no contaminating free antibody or rGel. The final material contained both antibody + 1 rGel (major) and antibody + 2 rGel (minor) species. We analyzed Fn14 expression in human tumor cell lines using flow cytometry and Western blot analysis. Fn14 was expressed in a variety of tumor lines including breast, brain, bladder, skin, lung, ovarian, pancreatic, colon, prostate, and cervical tumor cell lines. Both ITEM4 and ITEM4-rGel were found to bind to cells to an equivalent extent. Confocal immunofluoresence studies showed that ITEM4-rGel specifically and rapidly (within 2 hrs) internalized into MDA-MB-231 breast cancer cells and T-24 bladder cancer cells but not into Fn14-deficient mouse embryonic fibroblasts. Cytotoxicity studies against 22 different tumor cell lines showed that ITEM4-rGel was highly cytotoxic to Fn14-expressing cells (IC50 ranged from 0.8 pM-25 nM) and was 50 to 0.5 ×106 fold more potent than free rGel. Minimum contact time studies showed that as little as 12 hr exposure achieved maximal cytotoxic effect. Mechanistic studies showed that ITEM4-rGel induced HMGB1 release following treatment of MDA-MB-231, T-24, AAB 527, and BxPC-3 cells. In addition, target cells showed induction of apoptosis, as measured by Annexin V staining and caspase-3 cleavage. ITEM4-rGel treatment also induced the non-canonical NF-κB pathway, up-regulated the tumor suppressor protein p53 and down-regulated survivin expression. Preliminary mouse xenograft tumor model studies are ongoing. These data suggest that the ITEM4-rGel construct may warrant further development as a novel therapeutic agent against a broad range of solid tumor types. Research conducted, in part, by the Clayton Foundation for Research (MGR), and supported by NIH grant NS55126 (JAW) and DOD Breast Cancer Concept Award BC086135 (JAW).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2574.
Abstract 2578: Efficacy of anti-CD22 antibody drug-conjugates in Ramos and Raji tumor xenograft models
Authors: Pan Chin , Chong Colin , Cortez Orville , Witte Alison , Nazeer Ayesha , Rao-Naik Chetana , Huber Mary , Stevens Alice , Zhang Qian , Masood Asna , Gangwar Sanjeev , King David , Devaux Brigitte , Cardarelli Pina
Published: February 2011

CD22 is a well-validated target for immunotherapy on B cell tumors. CD22 is a B lymphoid lineage-specific differentiation antigen, and its cell surface expression coincides with IgD expression in human. CD22 expression is upregulated on mature B cells, and is lost upon terminal differentiation to plasma cells. CD22 is also highly expressed on B cell tumors including non-Hodgkin's lymphoma (NHL) and acute lymphocytic leukemia (ALL). Antibodies to CD22 rapidly internalize, making it an ideal target for an antibody drug conjugate (ADC) therapeutic approach. Human antibodies to CD22 have been generated. The antibodies bind B cells with high affinity and are rapidly internalized upon binding. Anti-CD22 conjugates linked to highly potent synthetic DNA minor-groove binding alkylating (MGBA) agents have been prepared and tested in vivo for the treatment of established Ramos and Raji subcutaneous tumor xenografts. Anti-tumor efficacy of the anti-CD22 conjugate was highly specific in comparison with the isotype control conjugate. The anti-CD22 conjugate at a single dose of 0.3 µmole/kg resulted in regression of established subcutaneous tumors with less than 5% body weight loss and no clinical signs of toxicity. The anti-CD22 conjugate at a single dose of 0.1 µmole/kg was more efficacious than Rituximab treatment on Ramos tumors. The anti-CD22 conjugate also had better tumor growth inhibition than an anti-CD19 conjugate. In summary, anti-CD22-ADCs have been prepared which show superior in vivo efficacy to Rituximab and to anti-CD19-ADCs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2578.
Abstract 2583: LA480, a bivalent humanized c-Met monoclonal antibody, inhibits tumor growth without eliciting significant agonist activity
Authors: Zeng Wei , Wortinger Mark , Yang Wei Jennifer , Peek Victoria , Yan Lei , Lu Jirong , Chow Chi-Kin , Vaillancourt Peter , Davies Julian , Denning Irene , Weir Spring , McClure Don , Chintharlapalli Sudhakar , Liu Ling
Published: February 2011

The receptor tyrosine kinase c-Met and its ligand HGF elicit multiple cellular activities including cell proliferation, motility, invasion, tubulogenesis, angiogenesis and anti-apoptosis. Dysregulation of this pathway has emerged as a crucial feature for many human tumors. However, past efforts in developing c-Met therapeutic antibodies that inhibit both ligand-dependent and ligand-independent c-Met activation have been largely unsuccessful due to agonist properties of the antibodies. In fact, c-Met antibodies exhibiting medium to strong agonist activity stimulate proliferation of both normal and tumor cells. We report here that LA480, a bivalent humanized monoclonal c-Met antibody, blocks HGF binding to c-Met and also induces c-Met internalization. Moreover, LA480 inhibits growth of xenograft tumors mediated by HGF-dependent and HGF-independent c-Met pathway activation. In order to evaluate whether LA480 has agonist activity, we tested LA480 in the following HGF-responsive biological assays: proliferation of primary human hepatocytes and tumor cell lines, scattering of DU145 cells, stimulation of HepG2 invasion and tubulogenesis, tube formation in endothelial and stromal cell co-cultures, and protection from apoptosis induced by staurospor in Caki-1 cells. A bivalent c-Met agonist antibody and HGF were included in the assays as positive controls, in addition to antibody isotype negative controls. Our results demonstrate that LA480 does not significantly stimulate cell proliferation, scattering, invasion, tubulogenesis, angiogenesis or apoptosis protection in the above assay systems. Under the same conditions, the agonist positive control c-Met antibody and HGF both significantly induced these biological effects. These unique properties of LA480 suggest that it may be a promising therapeutic reagent for treatment of cancers driven by ligand-dependent and ligand-independent c-Met activation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2583.
Abstract 2602: The cardiotoxicity and myocyte damage caused by small molecule anticancer tyrosine kinase inhibitors is correlated with lack of target specificity
Authors: Hasinoff Brian B. , Patel Daywin
Published: February 2011

The use of the new anticancer tyrosine kinase inhibitors (TKI) has revolutionized the treatment of certain cancers. However, the use of some of these results in cardiotoxicity. Large scale profiling data recently made available for the binding of 7 of the 9 FDA-approved tyrosine kinase inhibitors to a panel of 317 kinases has allowed us to correlate kinase inhibitor binding selectivity scores with TKI-induced damage to neonatal rat cardiac myocytes. The 7 TKIs that were the subject of this study were: imatinib (Gleevec), sunitinib (Sutent), dasatinib (Sprycel), sorafenib (Nexavar), lapatinib (Tykerb), gefitinib (Iressa), and erlotinib (Tarceva). The tyrosine kinase selectivity scores, but not the serine-threonine kinase scores, were highly correlated with the myocyte damaging effects of the TKIs. Additionally, we showed that damage to myocytes gave a good rank order correlation with clinical cardiotoxicity. Finally, strength of TKI binding to colony stimulating factor 1 receptor (CSF1R) was highly correlated with myocyte damage, thus possibly implicating this kinase in contributing to TKI-induced cardiotoxicity. Support: CIHR and a Canada Research Chair in Drug Development to BBH.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2602.
Abstract 261: Epidermal growth factor receptor (EGFR)-mediated upregulation of matrix metalloproteinase-1(MMP-1) in glioblastoma cell lines involves multiple signaling pathways
Authors: Anand Monika , Zehner Zendra E. , Fillmore Helen L.
Published: February 2011

Glioblastoma Multiforme (GBM) is a devastating disease with an extremely poor prognosis primarily due to its invasive and infiltrative nature. Matrix metalloproteinases (MMPs) are important enzymes that regulate tumor microenvironment, alter cellular behavior and increase invasion and metastasis in wide variety of cancers. Previous studies from our laboratory have shown that MMP-1 is over expressed in GBM tissue and can influence glioma cell invasion in vitro. Since the epidermal growth factor receptor (EGFR) is amplified in human GBM, we wanted to determine the effect of EGFR activation by epidermal growth factor (EGF) on MMP-1 expression and invasion in human glioma cell lines and if so, determine the signaling mechanisms responsible for this induction. We stimulated glioma cell lines (T98 and U87) with EGF in the presence and absence of the EGFR inhibitor, AG1478. Inhibitors to multiple signaling pathways activated by EGFR induction were also used. All inhibitors tested were added to cells for 2 hrs prior to addition of EGF. In addition, transfections using AKT and STAT3 siRNA were conducted. Western Blotting was performed to examine the levels of MMP-1, EGFR, AKT, STAT3 and ERK. We observed that with EGF treatment, in addition to EGFR activation, AKT was phosphorylated, MMP-1 was induced and that in the presence of AG1478, AKT and EGFR phosphorylation was inhibited in a dose dependent manner. Importantly, MMP-1 up-regulation by EGF was abrogated in cells pretreated with AG1478. EGFR has been shown to up-regulate MAPK, PI3K and STAT3 pathways in glioma and other malignancies. Involvement of the MAPK pathway in the EGFR- mediated induction of MMP-1 was examined using the MAPK inhibitor, U0126. Only a modest decrease in MMP-1 levels was observed following treatment with EGF and U0126, suggesting potential inputs from other signaling pathways. Although there was a modest inhibition of AKT protein levels in cells treated with AKT siRNA, the levels of MMP-1 in these cells were significantly reduced. Current experiments focus on the role of AKT/PI3K and STAT3 signaling pathways in MMP-1 mediated glioma cell invasion.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 261.
Abstract 2613: Assessment of pharmacokinetics-pharmacodynamics and antitumor activities of hydroxamate- and mercaptoacetamide-based histone deacetylase inhibitors
Authors: Konsoula Zacharoula , Velena Alfredo , Cao Hong , Jung Mira Oh
Published: February 2011

Structurally diverse histone deacetylase inhibitors (HDACIs) have emerged as chemotherapeutic agents and have shown to cause differentiation, cell cycle arrest and apoptosis. As an initial step in identifying a clinically applicable HDACI, we evaluated the in vitro and the in vivo properties of two mercaptoacetamide (6MAQH and 5MABMA) and a hydroxamate (H6CAHA)-based HDACIs: 1) The growth inhibitory activities of these inhibitors were evaluated and compared against a subset of prostate cancer and non-malignant epithelial cell lines. 2) The in vitro permeability, solubility and lipophilicity properties of the HDACIs were assessed. 3) In vivo, the antitumor activities were determined following i.p. administration of the inhibitors (0.4 mg/Kg) using mice bearing PC3 tumor xenografts (n = 10). 4) The plasma pharmacokinetics of the HDACIs and their effect on the acetylation of histone H4 in tissues were determined in nude mice. The data demonstrated that mercaptoacetamides preferentially inhibited the growth of cancer than nonmalignant cells, whereas the hydroxamate showed toxicity at higher concentrations in both cancer and normal cells. The mercaptoacetamides also conferred higher solubility under the acidic environment of the stomach (pH 1.2) and lower under the neutral of the small intestine (pH 7.4) than the hydroxamate. All the HDACIs exhibited high permeability as well as lipophilicity values. In vivo, HDACIs treatment led to tumor growth inhibition (p < 0.001), which was sustained for at least 60 days. Plasma pharmacokinetics revealed that the area under the curve (AUC) was 8.08 ± 0.91 μM x h for H6CAHA, 4.97 ± 0.6 μM x h for 6MAQH μM x h, and 4.23 ± 0.43 μM x h for 5MABMA. The plasma half- lives for H6CAHA, 6MAQH and 5MABMA were 11.17 ± 0.87, 2.2 ± 0.33 and 1.98 ± 0.21 h, respectively. Taken together, these results provide support that the HDACIs target prostate cancer cells effectively, as evidenced by growth suppression in vitro and tumor growth inhibition in vivo. The mercaptoacetamide HDACIs preferentially inhibit the growth of cancer cells while exert limited effect on nonmalignant cells. However, the hydroxamate based HDACI exhibited superior in vivo pharmacological properties. Furthermore, the physicochemical and pharmacological characteristics of HDACIs provide a rationale for their further investigation as potent anticancer agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2613.
Abstract 2614: Anti-tumor efficacy and pharmacokinetics of the novel aptamer AS1411 in a continuous infusion nude rat xenograft model
Authors: Green Colin , Djeha Hakim , Bestwick Michael , Dobinson Donna , McLaughlin Fiona
Published: February 2011

AS1411 is a novel DNA aptamer that binds to the multi-functional protein nucleolin and induces cell death. AS1411 has shown activity at two different doses in combination with cytarabine in a phase II study of patients with AML.

We have previously shown that AS1411 has activity against a range of solid and hematological cancer cell lines, with IC50 values between 1 and 10 μM, when cells are exposed to AS1411 continuously for more than 3 days. We have also demonstrated efficacy in vivo in both lung (A549) and renal (A498) mouse xenografts. However, it has been challenging to provide optimal continuous dosing of AS1411 in mice; use of osmotic pumps or intraperitoneal bolus injection have been associated with low drug exposure. In the current study, we optimized the continuous infusion model by using nude, athymic rats with a surgically implanted catheter in a two-cycle xenograft study. Plasma and tumor samples were collected for PK determination, allowing a correlation of PK with efficacy.

The colorectal cell line HT29, which is sensitive to AS1411 in vitro, was used in this study. Cells (5×106) were implanted subcutaneously in the flank of female nude rats and tumors were allowed to grow to approximately 200 − 300 mm3 before surgical cannulation of the femoral vein. Following recovery, animals received AS1411 at 40, 80 or 180 mg/kg/day for two 7 day cycles of continuous infusion, 7 days apart. A vehicle control group received saline.

Animals in the 80 and 180 mg/kg/day groups exhibited a significant (p<0.01) reduction in tumor volume compared to control animals at day 33 and at day 22 (interim analysis); this was not observed for animals in the 40mg/kg/day group (40mg kg/day in this model does not directly correlate to the clinical dose of the same name). AS1411 was well-tolerated by all animals in all dose groups.

Plasma levels of AS1411 were measured at the three dose levels after one cycle of treatment. Mean AS1411 plasma concentrations were 0.7, 2.5 and 5.0 μM, for rats treated at 40, 80 and 180 mg/kg/day, respectively. The plasma concentrations in the two higher dose groups are within the range of the in vitro IC50 concentrations of a panel of cell lines.

We conclude that AS1411 shows activity in vivo in the HT29 nude rat xenograft model. Doses associated with significant reductions in tumor volume were those that produced plasma concentrations close to the IC50 level for AS1411. This correlation has been used in planning further clinical development of AS1411, including a phase IIb study of patients with AML.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2614.
Abstract 2618: Identification of multidrug response genes by meta-analysis based on ChemoFx® in human breast cancer cell lines
Authors: Shen Kui , Rice Shara , Wang Dakun , Gingrich Dave , Brower Stacey , Ervin Paul , Gabrin Michael , Song Nan
Published: February 2011

The success of chemotherapeutic agents to treat various forms of cancer has a long history. Unfortunately, a major cause of treatment failure is drug resistance to currently available chemotherapy agents. Understanding the mechanism of resistance to multiple drugs has been a subject of considerable interest. ChemoFx® holds the promise of not only determining which patient will respond to what therapy but also can be used to learn more about drug resistance while acting as a proxy to clinical outcome.

In this study, we used the ChemoFx® to identify response vs. non-response to seven different chemotherapeutic agents (paclitaxel, docetaxel, epirubicin, doxorubicin, gemcitabine, fluorouracil, cyclophosphamide) in 28 human breast cancer cell lines. Based on publically available gene expression profiles of these breast cancer cell lines and the ChemoFx® results, differentially expressed (DE) genes related to multi-drug response were identified through meta-analysis method. Five hundred thirty six DE genes were identified to be related to multidrug response at the false discovery rate of 0.05. To segregate the effect of ER status, we also performed meta-analysis within ER positive or ER negative breast cancer cell lines separately. Thirty seven DE genes were identified related to multiple drug response in ER negative breast cancer cell lines and 20 DE genes in ER positive cell lines. Among all these DE genes, only one is in common between ER positive and ER negative groups. These results suggest that multi-drug resistance is the result of not just one gene but the contribution of multiple genes. In addition, gene set enrichment analysis showed that multidrug response genes are involved in different biological processes in ER positive vs. ER negative cell lines. The dissimilarity of multidrug response genes in ER positive vs. ER negative shows the value of integrating multidrug response gene information with clinical factors to identify patients who are unlikely to benefit from current chemotherapeutic drugs. Moreover, understanding the mechanisms of multidrug response has the potential of identifying new therapeutic targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2618.
Abstract 2619: Sulfation of toremifene: Individual variability, isoform specificity, and contribution to toremifene pharmacogenomics
Authors: Edavana Vineetha Koroth , Williams Suzanne , Beggs Marjorie L. , Mercer Kelly , Yu Xinfeng , Zhang Xuemei , Caldwell David B. , Kadlubar Fred , Kadlubar Susan
Published: February 2011

Toremifene (TOR) is a selective estrogen receptor modulator (SERM) used in adjuvant therapy for breast cancer, and more recently is in clinical trials for prostate cancer prevention in patients with high grade PIN. The chemical structure of TOR differs from tamoxifen (TAM) only by the presence of a chlorine atom in the ethyl side chain. That difference results in distinct breakdown products of the two drugs, which may provide for a more favorable toxicity spectrum with TOR compared to TAM. TOR has a similar mechanism of action to that of TAM, in that its 4-hydroxy metabolites bind specifically to estrogen receptors and, as an estrogen receptor-TOR complex, to chromatin. Interestingly, studies have indicated that a subset of patients who fail on TAM therapy benefit from high-dose TOR therapy, indicating that pharmacogenomics could be an important determinant of response to treatment with TOR.

Several studies have indicated that functional genetic variants in the TAM metabolic pathway influence response to therapy, but to date, pharmacogenomic studies of patients treated with TOR are lacking. In order to perform candidate gene association studies, it is necessary to identify the enzymes involved in TOR metabolism. While the Phase I metabolism of TOR has been well-characterized, Phase II metabolism of the active 4-OH-TOR is not well-defined. In this study, we examined individual variability in sulfation of TOR, and found 20-fold variation in human liver cytosols from 100 subjects. Examination of recombinant sulfotransferases revealed that SULT1A1, SULT1E1, and to a lesser extent, SULT2A1 catalyzed the sulfation of TOR. SULT1A1 is the most highly expressed hepatic sulfotransferase, and there was a significant association between SULT1A1*1/*2 genotype and TOR sulfation in human liver cytosols (p=0.001). Since target tissue metabolism is also a critical determinant of clinical efficacy, we also examined the presence of sulfotransferase isoforms in normal prostate (n= 8), BPH tissue (n= 12), and prostate cancer (n=4). Quantitative RT-PCR analysis showed the presence of SULT1A1 and SULT2B1b in BPH and Prostate cancer tissues. These results indicate that variability in sulfation, in terms of both first-pass metabolism and target tissue metabolism, contributes to response to TOR for prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2619.
Abstract 2625: Proteasome inhibitor Bortezomib increases anti-cancer activity of novel anti-inflammatory anti-androgen Compound A
Authors: Yemelyanov Alexander , Budunova Irina
Published: February 2011

Signaling by the steroid hormone receptors plays a pivotal role in the development of prostate cancer. Androgens and the androgen receptor (AR) promote prostate tumorigenesis. In contrast, the glucocorticoid receptor (GR) plays tumor suppressive role in the prostate. The major molecular mechanisms underlying GR anti-cancer and anti-inflammatory effects are similar and based on GR transrepression that involves negative interaction between GR and other transcription factors. We anticipated that anti-inflammatory anti-androgens hold a great potential for prostate cancer treatment. Thus, we identified the potential AR/GR ligands with this functional profile by screening of selective GR activators (SEGRA) recently synthesized in USA and Europe as anti-inflammatory GR ligands with reduced side effects. The lead identified compound is Compound A (CpdA), a synthetic analogue of a hydroxyphenyl aziridine precursor isolated from the Namibian shrub Salsola Botschantzev. We and others showed that CpdA inhibits AR function, prevents GR dimerization and transactivation, but strongly enhances GR transrepression. It is known that proteasome inhibitors tightly control GR and AR degradation and function. We show here that the exposure of prostate cancer cells expressing endogenous AR and GR to proteasome inhibitor Bortezomib (BZ) resulted in strong degradation of AR and accumulation of GR. The androgen DHT prevented AR destabilization induced by BZ. In contrast to androgen, CpdA cooperated with BZ to decrease AR expression and function. In addition, BZ modified the functional profile of GR in a ligand-dependent fashion. In the presence of GR modulator CpdA, BZ did not induce GR transactivation but augmented CpdA effect on GR transrepression measured by the inhibition of several transcription factors such as NF-kB, AP-1 and STAT1. Finally we revealed a strong cooperation between CpdA and BZ in activation of apoptosis and endoplasmic reticular stress in prostate cancer cells. Overall, our data suggest that combination of BZ with steroid receptor modulators such as CpdA, has a high potential for PC therapy. Work is supported by RO1CA118890 (to IB) and ACS IL grant #160185 (to AY).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2625.
Abstract 2629: Carfilzomib, an irreversible proteasome inhibitor, induces caspase-dependent apoptosis and inhibits the growth of mantle cell lymphoma in vitro and in tumor-bearing SCID mice
Authors: Zhang Liang , Qian Jianfei , Yang Jing , Aujay Monette , Demo Susan , Yi Qing , Wang Michael
Published: February 2011

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma subtype with poor clinical outcome. The proteasome is a clinically proven therapeutic target for MCL. Bortezomib is a reversible proteasome inhibitor approved for MCL therapy. Carfilzomib, the new irreversible proteasome inhibitor with the chymotrypsin-like selectivity, has been shown to be effective in multiple myeloma. The objective of our study was to evaluate the therapeutic efficacy of carfilzomib in MCL in vitro and in vivo and to elucidate the mechanism of carfilzomib-mediated cell apoptosis. Four human MCL cell lines, SP53, MINO, Granta 519, and Jeko-1; freshly isolated primary MCL cells from four MCL patients; and normal peripheral blood mononuclear cells (PBMCs) from five healthy donors were treated with carfilzomib. A 3H-thymidine incorporation assay showed that carfilzomib not only inhibited the growth of the MCL cell lines but also freshly isolated MCL cells from patients in a dose-dependent manner. Interestingly, carfilzomib also inhibited the proliferation of PMA/ionomycin or anti-CD3 mAb/anti-CD28 mAb-activated, but not resting PBMCs from healthy donors. Flow cytometry analysis with fluorescence-labeled Annexin V and propidium iodide showed that carfilzomib induced apoptosis in both the cell lines and primary MCL cells in time- and dose-dependent manners. Notably, carfilzomib did not induce apoptosis of normal PBMCs. Carfilzomib was also effective and therapeutic in a MCL mouse model established in severe combined immunodeficient (SCID) mice. MINO cells (5 × 106) were inoculated subcutaneously into the right flank of SCID mice. Three weeks later, after palpable tumors developed, mice were treated intravenously with either vehicle alone (10% captisol) or carfilzomib (5 mg/kg) on day 1 and day2, dosing repeated weekly for 5 cycles. Tumor growth was significantly inhibited after carfilzomib treatment compared with vehicle control, and the survival time of tumor-bearing mice was significantly prolonged in the treatment group. Western blot analysis showed that apoptosis of MCL cells was induced through the activation of caspase cascades and PARP pathway. Pretreatment of cells with pan-caspase inhibitor (z-VAD) but not caspase-8 inhibitor (z-IETD) alone or caspase-9 inhibitor (z-LEHD) alone completely blocked carfilzomib-induced apoptosis. In conclusion, carfilzomib inhibited growth and induced apoptosis of MCL cells in vitro and in vivo. Cell apoptosis was induced via caspase-dependent signaling pathway. Our preclinical data indicate that carfilzomib may be used as a therapeutic agent in MCL treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2629.
Abstract 263: p38 MAPK is required for EGFR nuclear translocation
Authors: Hsu Sheng-Chieh , Hung Mien-Chie
Published: February 2011

The epidermal growth factor receptor (EGFR) severs as a mediator of signal cascades on the cell surface and translocates to the nucleus to control many cellular process including transcriptional regulation and DNA repair. However, the molecular mechanisms of EGFR nuclear translocation remain elusive. In this study, we show that, in addition of EGF, nuclear translocation of EGFR was induced by several p38 MAPK activating reagents including UV and cisplatin. The p38 MAPK activation correlated with EGFR nuclear translocation. To further examine the role of p38 MAPK in the EGFR nuclear translocation, p38 MAPK inhibitors, dominate negative p38 MAPK and p38 MAPK siRNA were used to inhibit UV-induced EGFR nuclear translocation. Consequently, EGFR nuclear translocation can be induced by p38 MAPK activator. Thus, we demonstrate here that p38 MAPK is required for EGFR nuclear translocation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 263.