bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A254: Systemic injection of human neural stem cells expressing anti-cancer agent targets invasive gliomas and induces tumor regression in combination with a cardiac glycoside.
Authors: Teng Jian , Hejazi Seyedali , Badr Christian E. , Tannous Bakhos A.
Published: August 2014

Glioblastoma multiforme (GBM) is the most common and most aggressive malignant form of brain tumors in human. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is regarded as an anticancer agent, however, a considerable number of tumor types, including GBM, are resistant to TRAIL. Also, TRAIL therapeutic use in vivo is limited by a short half-life in plasma due to a rapid clearance by the kidney and a poor penetration across the blood-brain barrier. The tumor-tropic properties of neural stem cells (NSCs) could serve as a novel strategy to deliver therapeutic genes to tumors in the brain. Furthermore, we have previously reported that the cardiac glycoside lanatoside C sensitizes GBM cells to TRAIL-induced apoptosis. In this study, we engineered human neural stem cell to synthesize and secrete an active form of TRAIL (NSC-sTRAIL) as well as the secreted Gaussia luciferase (Gluc) as a blood marker for cell proliferation. We showed that these cells selectively migrate toward GBM stem-like cells (GSCs) in a transwell assay. However, GSCs’ growth was only decreased by 11.6%. When this co-culture was treated with lanatoside C, GSCs’ growth was inhibited by 81.5% in a caspase-mediated manner. We then tested this combined therapy in an invasive orthotopic model using primary GSC neurospheres expressing firefly luciferase. Upon systemic injection, Gluc blood assay showed that at the next day at least 30% of NSC-sTRAIL, and after 5 weeks up to 0.5% of these cells survived. Histological analysis showed that the NSC-sTRAIL cells crossed the blood-brain barrier and migrated toward invasive GSC tumors. Bioluminescence imaging showed that tumors in mice treated with NSC-sTRAIL cells in combination with lanatoside C resulted in significant tumor regression and mouse survival elongation as compared to single therapy. Taken together, this study demonstrated that systemic injection of neural stem cells targets invasive brain tumors and could be used to deliver an anticancer agent such as sTRAIL which yields significant tumor regression when used in combination with lanatoside C.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A254.

Citation Format: Jian Teng, Seyedali Hejazi, Christian E. Badr, Bakhos A. Tannous. Systemic injection of human neural stem cells expressing anti-cancer agent targets invasive gliomas and induces tumor regression in combination with a cardiac glycoside. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A254.
Abstract A257: Stereospecific trapping of PARP-DNA complexes by BMN 673 and comparison with olaparib and rucaparib.
Authors: Murai Junko , Huang Shar-yin N. , Renaud Amelie , Zhang Yiping , Ji Jiuping , Takeda Shunichi , Morris Joel , Teicher Beverly , Doroshow James H. , Pommier Yves
Published: August 2014

Anti-poly(ADP-ribose)polymerase (PARP) drugs were initially developed as catalytic inhibitors to block the repair of DNA single-strand breaks. Yet, several PARP inhibitors have an additional cytotoxic mechanism by trapping PARP-DNA complexes; both olaparib and niraparib act as PARP poisons at pharmacological concentrations (Murai et al., Cancer Res, 2012). Here, we evaluate the novel PARP inhibitor, BMN 673, and compare its effects on PARP1 and PARP2 with two other clinical PARP inhibitors, olaparib and rucaparib, using biochemical and cellular assays in genetically-modified chicken DT40 and human cancer cell lines. We show that BMN 673, olaparib, and rucaparib are similarly potent at inhibiting PARP catalytic activity. At the same time, BMN 673 is ∼100-fold more potent at trapping PARP-DNA complexes and more cytotoxic as a single agent than olaparib, while olaparib and rucaparib show similar potencies in trapping PARP-DNA complexes. The high level of resistance of PARP1/2 knockout cells to BMN 673 demonstrates the selectivity of BMN 673 for PARP1/2. Moreover, we show that BMN 673 acts by stereospecific binding to PARP1 as its enantiomer, LT674, is several orders of magnitude less efficient, and that BMN 673 is more cytotoxic than olaparib and rucaparib in combination with the DNA alkylating agents methyl methane sulfonate (MMS) and temozolomide. Our study demonstrates that BMN 673 is the most potent clinical PARP inhibitor to date with the highest efficiency at trapping PARP-DNA complexes.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A257.

Citation Format: Junko Murai, Shar-yin N. Huang, Amelie Renaud, Yiping Zhang, Jiuping Ji, Shunichi Takeda, Joel Morris, Beverly Teicher, James H. Doroshow, Yves Pommier. Stereospecific trapping of PARP-DNA complexes by BMN 673 and comparison with olaparib and rucaparib. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A257.
Abstract A262: Antiandrogen modulation of prostate-specific membrane antigen (PSMA): Dynamics and synergy with PSMA-targeted therapy.
Authors: Murga Jose D. , Magargal Wells W. , Moorji Sameer M. , DiPippo Vincent A. , Olson William C.
Published: August 2014

Introduction: Recent approvals of new prostate cancer (PCa) drugs and a growing number of pipeline agents have created opportunities for designing rational drug combinations. Potent antiandrogens such as enzalutamide and abiraterone affect expression of numerous androgen-regulated molecules, including PSMA, a well-characterized cell-surface target for PCa therapy.

Methods: Cytotoxicity and the kinetics of antigen expression were evaluated in PCa cell lines (LNCaP, C4-2 and 22Rv1) that vary according to androgen dependence and level of PSMA expression. Expression of PSMA and prostate-specific antigen (PSA) was evaluated over time in cells cultured in enzalutamide or abiraterone. Reversibility was examined following drug washout. Cells were tested for susceptibility to antiandrogens used alone and in combination with PSMA ADC, which is a fully human PSMA monoclonal antibody conjugated to the microtubule disrupting agent monomethyl auristatin E (MMAE). Potential drug synergy or antagonism was evaluated using the Combination Index and Bliss independence methods.

Results: In androgen-dependent LNCaP cells, enzalutamide and abiraterone exerted antiproliferative effects that were accompanied by a 2- to 3-fold increase in PSMA expression and a decrease in PSA expression. PSMA expression reached maximum levels after four weeks’ culture in enzalutamide and returned to baseline levels within days following enzalutamide removal. In androgen-independent C4-2 cells, enzalutamide and abiraterone increased PSMA expression in the absence of any significant anti-proliferative effect. PSMA ADC exhibited synergistic antitumor activity with both enzalutamide and abiraterone in LNCaP and C4-2 cells. Lesser effects were observed using 22Rv1 cells, an androgen-independent cell line with low basal expression of PSMA.

Conclusions: Enzalutamide and abiraterone significantly and reversibly augmented PSMA expression and potentiated the activity of PSMA ADC in androgen-dependent and -independent PCa cell lines in vitro. In androgen-independent cells, the effects on PSMA expression and PSMA ADC activity were uncoupled from any anti-proliferative effect of the antiandrogens. The findings support clinical exploration of regimens that combine potent antiandrogens and PSMA-targeted therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A262.

Citation Format: Jose D. Murga, Wells W. Magargal, Sameer M. Moorji, Vincent A. DiPippo, William C. Olson. Antiandrogen modulation of prostate-specific membrane antigen (PSMA): Dynamics and synergy with PSMA-targeted therapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A262.
Abstract A279: Preclinical evaluation of AMG 925, a FLT3/CDK4 dual kinase inhibitor.
Authors: Dai Kang , Keegan Kathleen , Li Zhihong , Ji Ma , Li Cong , Eksterowicz John , Suzanne Coberly , Hollenback David , Weidner Margret , Huard Justin , Liang Lingming , Alba Grace , Orf Jessica , Lo Mei-Chu , Zhao Sharon , Ngo Rachel , Chen Ada , Liu Lily , Carlson Timothy , McGee Lawrence R. , Medina Julio , Kamb Alexander , Wickramasinghe Dineli
Published: August 2014

Acute myeloid leukemia (AML) remains a serious unmet medical need. Despite high remission rates with chemotherapy standard care treatment, the disease eventually relapses. Activating FLT3 mutations are found in approximately 30% of AML patients. Targeting FLT3 receptor tyrosine kinase has shown encouraging results in treating FLT3-mutated AML. Responses, however, are not sustained and acquired resistance has been a clinical challenge. Treatment options to overcome resistance are currently the focus of research. We report here preclinical evaluation of AMG 925, a potent, selective and bioavailable FLT3/CDK4 dual kinase inhibitor. The compound inhibited AML xenograft tumor growth by >99% without detectable body weight loss. AMG 925 was also found to inhibit FLT3 mutants (e.g, D835Y) that are resistant to the current FLT3 inhibitors (e.g., quizartinib/AC220, sorafenib). CDK4 is a cyclinD-dependent kinase that plays an essential central role in regulating cell proliferation in response to external growth signals. A critical role of the CDK4-Rb pathway in cancer development has been well established. CDK4 specific inhibitors are being developed for treating Rb positive cancer. AMG 925, which combines inhibition of two kinases essential for proliferation and survival of FLT3-mutated AML cells, may improve clinical response rates.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A279.

Citation Format: Kang Dai, Kathleen Keegan, Zhihong Li, Ma Ji, Cong Li, John Eksterowicz, Coberly Suzanne, David Hollenback, Margret Weidner, Justin Huard, Lingming Liang, Grace Alba, Jessica Orf, Mei-Chu Lo, Sharon Zhao, Rachel Ngo, Ada Chen, Lily Liu, Timothy Carlson, Lawrence R. McGee, Julio Medina, Alexander Kamb, Dineli Wickramasinghe. Preclinical evaluation of AMG 925, a FLT3/CDK4 dual kinase inhibitor. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A279.
Abstract A289: Novel ATP-competitive MEK inhibitor E6201 is effective against vemurafenib-resistant melanoma harboring the MEK1-C121S mutation.
Authors: Narita Yusuke , Okamoto Kiyoshi , Kawada Megumi Ikemori , Takase Kazuma , Minoshima Yukinori , Kodama Kotaro , Iwata Masao
Published: August 2014

Many clinical cases of acquired resistance to the BRAF inhibitor vemurafenib have recently been reported. One of the causes of this acquired resistance is the BRAF downstream kinase point mutation MEK1-C121S. This mutation confers resistance to not only vemurafenib, but also to the allosteric MEK inhibitor selumetinib (AZD6244). Here, we investigated the pharmacological activities and effectiveness of the novel MEK inhibitor E6201 against BRAF-V600E mutant melanoma harboring the MEK1-C121S mutation. A cell-free assay confirmed that E6201 is an ATP-competitive MEK inhibitor meaning it has a different binding mode with MEK compared with allosteric MEK inhibitors. E6201 is more effective against BRAF-V600E mutant melanoma compared with BRAF wild-type melanoma based on MEK inhibition. We found that the acquired MEK1-C121S mutation in BRAF-V600E mutant melanoma conferred resistance to both vemurafenib and selumetinib but not E6201. The effectiveness of E6201 is a result of its binding with MEK1 far from the C121S point mutation so the mutation is unable influence the MAPK pathway inhibitory activity. We conclude that E6201 is a potential therapeutic choice for improving the clinical outcome of vemurafenib-based therapy. However, further validation is needed.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A289.

Citation Format: Yusuke Narita, Kiyoshi Okamoto, Megumi Ikemori Kawada, Kazuma Takase, Yukinori Minoshima, Kotaro Kodama, Masao Iwata. Novel ATP-competitive MEK inhibitor E6201 is effective against vemurafenib-resistant melanoma harboring the MEK1-C121S mutation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A289.
Abstract A290: Kinase activity in vemurafenib-sensitive and resistant BRAF-mutant melanoma cells.
Authors: Risberg Karianne , Røe Kathrine , Ree Anne H.
Published: August 2014

In advanced melanoma, therapeutic targeting of the MAPK signaling pathway with vemurafenib, a potent inhibitor of the BRAFV600E-encoded signaling molecule, commonly results in rapid and substantial tumor responses, but limited durability of the clinical benefit. Therapy resistance inevitably develops either via reactivation of the MAPK (RAF/MEK/ERK) pathway or via bypass mechanisms, such as PI3K/AKT/mTOR-mediated signaling; however, no one mechanism of resistance has been consistently observed on disease progression. In preclinical models, dual inhibition of the MAPK pathway (by MEK inhibitors) and PI3K/AKT/mTOR signaling has shown to be an effective strategy at overcoming this type of resistance, and clinical studies are ongoing.

Hypothesizing that different patterns of composite kinase signaling activities in BRAF-mutant melanoma may reflect the response of vemurafenib and other inhibitors (e.g. MEK and AKT inhibitors), we analyzed the tyrosine kinase activity profiles generated by a vemurafenib sensitive melanoma cell line to a vemurafenib resistant melanoma cell line, both harbouring the BRAFV600E mutation. Of note, both cell lines were derived from metastatic tumor biopsies sampled from a patient with disseminated melanoma disease, participating in the BRIM-2 trial, before commencing vemurafenib treatment and at six weeks on treatment. The patient experienced partial therapy response lasting for 15 weeks before disease progression.

Interestingly, overall kinase activity was lower in the vemurafenib-resistant cell line, and the phosphorylation levels of a number of array substrates representing mediators of the MAPK and PI3K/AKT/mTOR signaling pathways were different in the cell lines sensitive and resistant to vemurafenib. Whilst treatment with vemurafenib, the MEK inhibitor U0126 and the AKT inhibitor M2266 resulted in limited effect in the vemurafenib-resistant cells, the drugs caused decreased in vitro cell viability in the vemurafenib-sensitive cell line.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A290.

Citation Format: Karianne Risberg, Kathrine Røe, Anne H. Ree. Kinase activity in vemurafenib-sensitive and resistant BRAF-mutant melanoma cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A290.
Abstract A293: Novel allosteric small molecule FAK inhibitors effectively inhibit cancer cell viability and clonogenicity.
Authors: Golubovskaya Vita M. , Lebedyeva Iryna , Ho Baotran , Yemma Michael , Singh Neha , Arcara Makayla , Ostrov David , Katritzky Alan , Cance William
Published: August 2014

Introduction: Focal Adhesion Kinase is overexpressed and activated in many types of tumors and plays an important role in survival. Recently, we developed FAK inhibitor, 1,2,4,5-benzenetetraamine tetrahydrochloride, called Y15, which inhibited FAK autophosphorylation and blocked breast, neuroblastoma, pancreatic, brain and colon cancer tumor growth. Experimental procedures: In this study, eight novel chemical derivatives of Y15, called Y15-I1-I8 were synthesized and tested in a panel of different cancer cell lines. To test the effect on FAK autophosphorylation we performed in vitro ADP-Glo kinase assay with recombinant FAK protein and Western blotting with Y397-FAK antibody. To test the in vivo effect of FAK inhibitors we performed MTT assay, AnnexinV apoptosis and clonogenicity assays in different cancer cell lines. As a control, we used Novartis NVP-TAE-226 FAK inhibitor. Results: By in vitro kinase assay Y15-I1-8 derivatives effectively inhibited FAK autophosphorylation with recombinant purified full length FAK protein. Western blotting demonstrated decreased Y397-FAK and Y418-Src phosphorylation in many cancer cell lines. In addition, these novel FAK inhibitors demonstrated decreased viability, increased apoptosis and inhibition of clonogenicity in lung, melanoma, glioblastoma, pancreatic, breast, and colon cancer cell lines. Some of the novel derivatives were better than parental Y15 inhibitor. Conclusion: Targeting FAK autophosphorylation with novel allosteric derivatives of Y15 is an effective therapy approach.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A293.

Citation Format: Vita M. Golubovskaya, Iryna Lebedyeva, Baotran Ho, Michael Yemma, Neha Singh, Makayla Arcara, David Ostrov, Alan Katritzky, William Cance. Novel allosteric small molecule FAK inhibitors effectively inhibit cancer cell viability and clonogenicity. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A293.
Abstract A45: Biomarker assay performance: The impact of the fixation method.
Authors: Badola Sunita
Published: August 2014

Recent advances in genomic technologies dramatically illustrated the complexity of cancer genomes. These discoveries provide new opportunities for drug development and ultimately better patient care by informing treatment choice decisions in addition to the insights into the mechanisms of response or relapse to therapy. Formalin fixed paraffin embedded (FFPE) tumor tissue specimens routinely collected in Oncology diagnostic practice present a number of challenges for performing molecular biomarker assays. These problems include chemical cross-linking RNA/DNA and protein, nucleic acid fragmentation, and reduced amount of extractable material. We evaluated a new fixative agent (PAXgene, Qiagen) to assess whether an alternative fixation method could alleviate problems presented by the FFPE specimens.

PAXgene preservation method was compared to FFPE and frozen tissue utilizing tumor material from xenograft and primary tumor mouse models. We compared the performance of the following techniques across three types of specimens: allele-discrimination PCR, gene expression profiling by QPCR, CNV (copy number variation) analysis, and IHC. DNA and RNA based assay performance including allele-specific PCR, gene expression profiling and CNV demonstrated similar results between frozen and PAXgene tumor specimens. Comparison of transcriptional profiling data between all there type of specimens demonstrated artifacts likely related to the formalin fixation process. Additionally, DNA extracted from PAXgene specimens had higher amount of amplifiable templates compared to DNA extracted from the FFPE specimens. Tissue sections from PAXgene fixed specimens exhibited preserved tissue morphology of acceptable quality. We carried out pAKT and PTEN IHC assays in PAXgene and FFPE tissue sections. The results demonstrated superior performance for pAKT in the PAXgene format. In the case of PTEN IHC assay, the standard FFPE based IHC assay protocol required substantial modifications.

Collecting tumor biopsies in the PAXgene format provides an opportunity of conducting both molecular and tissue based biomarker assays from a single tumor specimen.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A45.

Citation Format: Sunita Badola. Biomarker assay performance: The impact of the fixation method. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A45.
Abstract A46: Expression of biomarkers in cervical intraepithelial neoplasia: Potential use screening.
Authors: Espinosa Garcia Ana Maria , Alfaro Ana , Palma Icela , Duran Marco , Beumen Jaime
Published: August 2014

Background: Persistent infection of high-risk Human papillomavirus (HPV) is recognized as a necessary cause of cervical cancer. Replication and viral integration into the cervix depend on the orderly expression of genes produced by viruses, by inducing the overexpression of multiple molecular proteins or biomarkers. Recently we have identified, 6 genes (CCNB2, CDC20, PRC1, SYCP2, NUSAP1 and CDKN3), which are proposed as universal molecular targets with a sensitivity and specificity close to100%, in cervical cancer.

Objective: evaluate the expression of these genes in cervical intraepithelial neoplasia (CIN).

Material and method: In this retrospective study we assessed the protein expression of 6 candidates tissue-based biomarkers (CCNB2, CDC20, PRC1, SYCP2, NUSAP1 and CDKN3) in a population based cohort of 200 cervical intraepithelial neoplasia that was collected over the period from 2008 to 2013. The tissue blocks were available and used for tissue microarray (TMA) construction, which included also samples of healthy epithelium. Quantitative RT-PCR was performed to validate expression of genes.

Results: The expression of these genes was observed in cervical intraepithelial neoplasia with different pattern shown previously in tumors, but in progression with the advance of the lesion, also shown by IH, evaluated samples, finding a correlation in both methods.

Conclusion: These results, may offer an additional strategy to current methods of the PAP, which is of greater use in our population. A test with greater sensitivity and specificity to identify lesions of high grade with more specificity can be a useful tool for cervical cancer screening.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A46.

Citation Format: Ana Maria Espinosa Garcia, Ana Alfaro, Icela Palma, Marco Duran, Jaime Beumen. Expression of biomarkers in cervical intraepithelial neoplasia: Potential use screening. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A46.
Abstract A49: Anti-DLL4 antibodies inhibit cancer stem cells in small cell lung cancer.
Authors: Strout Patrick , Korade Martin , Leow Ching Ching , Inigo Ivan , Thomas Suneetha , Hurt Elaine , Chesebrough Jon , Kamal Adeela , Cho Song
Published: August 2014

Small cell lung cancer (SCLC) is a very aggressive lung cancer with features suggesting enrichment in cancer stem cells (CSCs). Delta-like ligand 4 (DLL4) is a membrane bound ligand for Notch receptors critical for functional angiogenesis. Blocking DLL4 signaling increases the density of nonfunctional blood vessels and hypoxia of tumors, and thereby inhibits growth of tumor xenografts in mice. In addition, growing evidence implicates DLL4 Notch signaling pathway in the maintenance of CSCs. Here we investigated the anti-CSC activity of anti-DLL4 mAbs using in vitro and in vivo models of SCLC. Biochemical and flow cytometry analyses revealed that multiple SCLC cell lines express DLL4, and notably, SCLC spheres cultured under CSC-enriching conditions express higher levels of DLL4. Prior to determining the ability of anti-DLL4 mAb in inhibiting CSC in vivo, we first characterized the phenotype of CSCs in the SCLC cell line NCI-H69. NCI-H69 cells enriched for high CD133 expression were more tumorigenic and expressed higher levels of Nanog, Oct 3/4, and EZH2, which are genes crucial for maintenance of CSCs, than cells with low or negative levels of CD133. Moreover, RNA level of DLL4 was found to be three fold higher in CD133 high cells compared to CD133 low cells, suggesting that expression of DLL4 correlates with the CSC phenotype. In vivo, an anti-DLL4 antibody leads to inhibition of NCI-H69 tumor growth when the antibody is administered as a single agent, or in combination with cisplatin+etoposide or topotecan, chemotherapy agents commonly used in treatment of SCLC. To determine if blockade of DLL4 inhibits CSCs in vivo, NCI-H69 tumor xenografts treated with anti-DLL4 mAb were analyzed by flow cytometry. A subset of dissociated tumor cells expressed CD133 and DLL4, and a reduction of these populations of cells was observed in the anti-DLL4 antibody treated groups. In summary, these studies highlight that, in addition to vascular expression, (1) DLL4 is frequently expressed in SCLC cells, (2) DLL4 expression correlates with a CSC phenotype, and (3) that DLL4 blockade using an anti-DLL4 mAb results in inhibition of CSCs.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A49.

Citation Format: Patrick Strout, Martin Korade, Ching Ching Leow, Ivan Inigo, Suneetha Thomas, Elaine Hurt, Jon Chesebrough, Adeela Kamal, Song Cho. Anti-DLL4 antibodies inhibit cancer stem cells in small cell lung cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A49.
Abstract A53: Yin Yang 1 (YY1) regulates EMT via transcriptional activation of Snail and its overexpression in cancer stem cells (CSCs) in prostate cancer: Clinical significance.
Authors: Baritaki Stavroula , Rapozzi Valentina , Pelayo Rosana , Vega Mario , Huerta-Yepez Sara , Bonavida Benjamin
Published: August 2014

The epithelial to mesenchymal transition (EMT) is a cellular program that confers on neoplastic cells the biological traits needed to accomplish the metastatic cascade. The activation of EMT has been associated with the acquisition of stem cell traits, i.e., cancer stem cells (CSCs). CSCs have been reported to display EMT characteristics. Further, both EMT+ cells and CSCs exhibit a drug-resistant phenotype, hence, there is an urgent need to identify new therapeutic targets to eliminate both CSCs and EMT+ cells. Our previous findings and others’ demonstrated that the transcription factor Yin Yang 1 (YY1) regulates both the drug resistance and the metastasis-inducer Snail. Thus, we hypothesized that YY1 might be a multi-potential therapeutic target. We used human prostate carcinoma cell lines (PC3 EMT+ and LnCaP EMT-) as models. We demonstrate that overexpression of YY1 in LnCaP rendered the cells EMT+ (Snail+, E cadherin-, RKIP-). In contrast, treatment of PC3 with siRNA YY1 reverted the cells to the MET phenotype. Analysis by IHC in TMA of human prostate cancer tissues showed a positive correlation between the expression of Snail and YY1. Further, bioinformatic analysis corroborated the coexpression of Snail and YY1 in prostate cancer. Isolation of CSCs (CD44+, CD133+, CD24+) from PC3 cells exhibited overexpression of YY1 and other EMT markers. The inhibition of YY1 by various chemical inhibitors sensitized the resistant tumor cells to apoptosis to both chemo/immuno-cytotoxic drugs. These findings demonstrate that YY1 regulates EMT and drug resistance and is a prognostic biomarker. Further, we suggest that YY1 is a novel therapeutic target for the elimination of CSCs and metastasis in prostate cancer. Based on YY1 overexpression in many tumor types, we suggest that the present findings and their clinical significance may also be generalized to other cancers.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A53.

Citation Format: Stavroula Baritaki, Valentina Rapozzi, Rosana Pelayo, Mario Vega, Sara Huerta-Yepez, Benjamin Bonavida. Yin Yang 1 (YY1) regulates EMT via transcriptional activation of Snail and its overexpression in cancer stem cells (CSCs) in prostate cancer: Clinical significance. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A53.
Abstract A61: Characterization of KRAS-driven survival signaling networks via phosphoproteomics in lung cancer.
Authors: Kim Jae-Young , Welsh Eric A. , Fang Bin , Li Jiannong , Eschrich Steven A. , Koomen John , Haura Eric B.
Published: August 2014

KRAS mutations account for development of approximately 30% of lung adenocarcinomas, yet therapeutic options remain limited. To better understand KRAS-mediated survival mechanisms, we characterized phenotypic effects of KRAS knockdown as well as inhibition of its downstream effectors, including MEK, PI3K and RalB using 11 KRAS mutant non-small cell lung cancer cell lines. We observed only 2 cell lines with clear evidence of apoptosis after shRNA-mediated KRAS knockdown (H23 and Calu6). Interestingly, neither pharmacologic inhibition of MEK and PI3K nor knockdown of RalB fully recapitulated apoptotic phenotypes observed upon KRAS knockdown in these KRAS-sensitive lung cancer cells, suggesting that KRAS promotes survival through additional mechanisms. In order to identify novel KRAS survival pathways, we searched for altered phosphoproteins following shRNA-mediated KRAS knockdown using mass spectrometry (MS)-based phosphoproteomics. Stable isotope labeling by amino acids in cell culture (SILAC) was performed and phosphopeptides (p-Ser/Thr/Tyr) were purified using immobilized metal affinity chromatography (IMAC) resin, then analyzed by LC-MS/MS from sh-control or sh-KRAS-infected H23 lung adenocarcinoma cells. In total, we identified 2,878 phosphopeptides, corresponding to 1375 phosphoproteins, of which 210 phosphopeptides were upregulated and 204 phosphopeptides were downregulated after KRAS knockdown (cutoff: 1.5 fold). Using the altered phosphopeptides, we composed a cohesive network view to KRAS-regulated phosphoproteins (Kim et al. PNAS, 110;12414-12419), which revealed that KRAS regulates phosphorylation of cyclin-dependent kinase 1 and 2 (CDK1/2), and downstream mitotic targets. We also observed that KRAS knockdown activates adaptive resistance mechanisms via increased phosphorylation of RAF, PRAS40 and YAP1.

We are currently characterizing mitosis-related KRAS functions. Additionally, we are evaluating adaptive resistance mechanisms followed by loss of KRAS by analyzing KRAS-regulated phosphoproteome in cells harboring KRAS mutations but resistant to KRAS loss. These studies will provide better insights into KRAS-regulated survival signaling mechanisms and adaptive responses, which could offer rational co-targeting strategies. Updated work will be presented.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A61.

Citation Format: Jae-Young Kim, Eric A. Welsh, Bin Fang, Jiannong Li, Steven A. Eschrich, John Koomen, Eric B. Haura. Characterization of KRAS-driven survival signaling networks via phosphoproteomics in lung cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A61.
Abstract A65: Characterization of CBP/p300-mediated butyrate-induced Wnt activity in colonic microadenoma cells.
Authors: Lazarova Darina L. , Chiaro Christopher , Wong Terrence , Bordonaro Michael
Published: August 2014

Objectives of the study: We wished to (a) compare gene expression profiles between a colonic microadenoma cell line (LT97) and a metastatic colorectal cancer (CRC) cell line (SW620) in the presence and absence of butyrate, (b) determine whether the sensitivity of LT97 cells to the growth suppressive effects of butyrate correlates to a high-fold upregulation of Wnt signaling in these cells, and (c) evaluate how modulation of CBP/p300-mediated Wnt signaling influences the ability of butyrate to upregulate Wnt activity in LT97 cells.

Methods: RNA was isolated from mock treated or butyrate treated LT97 microadenoma cells or SW620 metastatic CRC cells, followed by full human genome microarray analysis (Genus Biosystems). Colonic cells were transfected with Wnt reporter plasmids and treated with ICG-001 (which inhibits CBP-mediated Wnt activity) or co-transfected with a p300 expression vector or with an expression vector for KLF4, which inhibits CBP/p300 association with beta-catenin. Reporter assays, western blotting, and caspase assays were performed.

Results: We demonstrate that LT97 colonic microadenoma cells differ substantially in gene expression profiles compared to a metastatic CRC cell line (SW620), both in the presence and absence of butyrate. Further, we demonstrate that the high degree of sensitivity to the growth repressive effects of butyrate of LT97 cells correlates to a marked butyrate-induced hyperactivation of Wnt activity in that cell line. Further, the induction of Wnt activity by butyrate in LT97 cells is sensitive to treatment with ICG-001, overexpression of CBP or p300, or blockade of CBP/p300-mediated Wnt activity by the transcription factor KLF4.

Conclusions: Microadenoma cells, reflecting very early stage colonic neoplasia, are highly sensitive to the effects of butyrate on Wnt signaling, in a manner dependent upon CBP/p300. The findings generated from this study may lead to approaches to modulate the action of CBP/p300-mediated Wnt signaling transcriptional programs for therapeutic or chemopreventive effect.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A65.

Citation Format: Darina L. Lazarova, Christopher Chiaro, Terrence Wong, Michael Bordonaro. Characterization of CBP/p300-mediated butyrate-induced Wnt activity in colonic microadenoma cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A65.
Abstract A7: Minocycline regulates Hypoxia-Inducible Factor-1α expression through the induction of its degradation in ovarian cancer: in vitro and in vivo studies.
Authors: Ataie-Kachoie Parvin , Pourgholami Mohammad H. , Morris David L.
Published: August 2014

Experimental data suggest therapeutic advantage from selective disruption of the hypoxia response in cancer. We recently found that minocycline decreases tumor VEGF expression in ovarian tumor xenografts in mice and herein report a companion laboratory study to test if this effect was the result of hypoxia-inducible factor (HIF) inhibition. Human ovarian carcinoma cell lines (OVCAR-3, SKOV-3 and A2780) were treated with minocycline in normoxic and hypoxic conditions and also in the presence of hypoxia-mimetic agent deferoxamine in vitro. Two different in vivo experiments investigated miocycline effects after single dose (30 mg/kg, 4 or 24 h) or longer exposure in nude mice bearing OVCAR-3 xenografts. Treatment with minocycline inhibited the accumulation of HIF-1alpha in a concentration-dependent fashion in vitro. A similar effect of minocycline was seen in vivo. Furthermore, the inhibtory effect of minocycline on HIF-1alpha was found to be associated with a significant decrease in HIF-1alpha half-life showing that minocycline enhances degradtion of HIF-1alpha. These data warrents further evaluation of minocycline in the treatment of ovarian cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A7.

Citation Format: Parvin Ataie-Kachoie, Mohammad H. Pourgholami, David L. Morris. Minocycline regulates Hypoxia-Inducible Factor-1α expression through the induction of its degradation in ovarian cancer: in vitro and in vivo studies. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A7.
Abstract A80: Cancer-specific targeting nanomicelles for diagnosis and treatment of bladder cancer.
Authors: Pan Amy Wang , Lin Tzu-yin , Zhang Hongyong , Goodwin Neal , Pan Chong-xian , Li Yuanpei , Lam Kit
Published: August 2014

Background: We previously developed a bladder cancer-specific targeting ligand named PLZ4 (amino acid sequence: cQDGRMGFc) that can specifically bind to both human and dog bladder cancer cells in vitro and in vivo. We have also developed a nanoscale micellular drug delivery platform. To minimize premature drug release during circulation, disulfide crosslinks are introduced to the micelles, which are cleaved under the intracellular reducing environment, where the drugs are released. Here, we assess the antitumor activity and toxicity of the PLZ4-coated and paclitaxel (PTX)-loaded micelles, with or without disulfide crosslinks.

Materials and Methods: Micelle-building monomers (ie, telodendrimers) are synthesized through conjugation of polyethylene glycol with cysteine (for disulfide crosslink) and a cholic acid cluster at one end and PLZ4 at the other. Such monomers self-assemble under aqueous condition to form micelles. Human bladder cancer cell line 5637 and patient-derived xenografts (PDX) are used for in vitro and in vivo drug delivery studies.

Results: PLZ4-coated micelles are about 20 nm in diameter. The PTX loading capacity is approximately 5 mg/ml in 20 mg of telodendrimers. PLZ4 confers cancer-specific drug delivery both in vitro and in vivo. Formulation of PTX in micelles significantly decreases the toxicity and allows intravenous administration of three times the maximum tolerated dose without increasing the toxicity, and improves the overall survival of mice carrying patient-derived bladder cancer xenografts to 64 days (without PLZ4 on micelle surface) and 76 days (PLZ4 targeting micelles) when compared to free parental PTX at 27 days (p<0.0001). In contrast to free paclitaxel in Cremophor (Taxol®), the micelle formulation of PTX does not induce mast cell degranulation. To determine the minimal requirement of PLZ4 for targeted drug delivery, we compared and found that micelles with 2% and 50% of PLZ4 on surface exhibited similar antitumor activity in mice carrying patient-derived xenografts.

Conclusion: Micellular formation of PTX coated with PLZ4 shows promising antitumor activity with decreased toxicity in the treatment of bladder cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A80.

Citation Format: Amy Wang Pan, Tzu-yin Lin, Hongyong Zhang, Neal Goodwin, Chong-xian Pan, Yuanpei Li, Kit Lam. Cancer-specific targeting nanomicelles for diagnosis and treatment of bladder cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A80.
Abstract A84: Nanoparticles-TRAIL demonstrated superior anti-tumor activity in champions and START tumor graft models.
Authors: Friedman Jay A. , Wick Michael , Gamez Lizette , Chaves Rodger , Bruckheimer Elizabeth , Kleinman Shifra , Perlstein Benny
Published: August 2014

Glioblastoma (GBM) is characterized by recurrence and resistance to conventional treatments such as chemotherapy and radiation. Therefore alternative therapeutic approaches are needed. TRAIL, a promising anti-tumor agent, induces apoptosis in cancer cells but not in normal cells. However, its short half-life and lack of efficient administration modes are serious impediments to its therapeutic efficacy. Nanoparticles (NP) have been used as effective delivery tools for various anticancer drugs. In the current study, TRAIL was covalently conjugated to the surface of iron oxide NP via its primary amine groups. The efficacy of TRAIL conjugated NP (NP-TRAIL), temozolomide (TMZ), and NP-TRAIL + TMZ was evaluated in vivo in three human TumorGraft models representing human GBM from Champions Oncology or START, ST108, CTG-0667 and ST146. Champions Oncology has developed an innovative platform that utilizes the implantation of primary human tumors in immune-deficient mice in a manner that preserves the biological properties of the original human tumor and results in more rigorous and clinically relevant models for drug discovery. Previous reports have shown the correlation between responsiveness observed in Champions TumorGraft™ models and clinical responses of the patients from which the models were derived. Results demonstrated significant tumor growth inhibition (TGI) following treatment with either TMZ alone or the combination of NP-TRAIL + TMZ. In TumorGraft model ST108 the combination demonstrated superior anti-tumor activity, 109% TGI, compared to TMZ alone, 53% TGI. Interestingly, in addition to tumor growth inhibition, the combination also demonstrated 2 partial responses whereas TMZ alone demonstrated none. The MGMT methylation status of the specimens, which is known to be correlated to the degree of response to TMZ, was evaluated and results were found to be low indicative of an unmethylated status.

In conclusion, our innovative compound NP-TRAIL was tested in vivo on three different TumorGraft models, each representing a GBM patient with unmethylated MGMT. The combination treatment of NPT+TMZ was found to be effective and superior to treatment with either NPT or TMZ as single agents and suggests that NP-TRAIL, in combination with TMZ, may be an effective treatment of GBM.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A84.

Citation Format: Jay A. Friedman, Michael Wick, Lizette Gamez, Rodger Chaves, Elizabeth Bruckheimer, Shifra Kleinman, Benny Perlstein. Nanoparticles-TRAIL demonstrated superior anti-tumor activity in champions and START tumor graft models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A84.
Abstract A91: Activating EGFR mutation, G719A, was selected in the c-MET amplified NSCLC-PDX-LU1901 during the treatments by c-MET inhibitors and the resistance development.
Authors: Yang Mengmeng , Cai Jie , Guo Sheng , Yu Shijun , Qian Wubin , Song Xiaoming , Wang Youzhu , Wery Jean-Pierre , Li Henry
Published: August 2014

We previously described the establishment of an Asian NSCLC patient derived xenograft (PDX), LU1901 (large cell carcinoma, or LCC), from a surgically removed patient tumor tissue, along with large panel of other NSCLC-PDX (1). LU1901 was found to have amplified c-MET gene and responded to multiple c-MET inhibitors, including crizotinib (near-complete regression) (1). Interestingly, we recently also observed that the TKI treatments, including crizotinib, induced rapid development of resistance against the TKIs (LU1902, LU1903) (2). However, efforts so far have yet to demonstrate mechanism causing the induced resistance (2). We are currently investigating many aspects of the resistant tumors, including histopathology and molecular features, e.g., further c-MET mutation, c-MET activation status, and inhibition by c-MET-TKI, etc. By hotspot sequencing of EGFR gene of LU1901 and LU1903 recently (Sanger Method), we found a known activating mutation, G719A in exon 18, was selected during the treatment that was also accompanied by the c-MET TKI resistance development. G719A has been found in small subset of patients (∼3%) (3), and has been associated with increased sensitivity to EGFR-TKIs (4), suggesting it could be a new driver mutation gained in resistant LU1903. At present, our working hypothesis is that the selection of G719A mutation of EGFR rendered LU1903 resistant to c-MET-TKI. We have planned further experiments to verify this hypothesis. As a first step, we performed RNAseq of the TKI-sensitive parental LU1901, and found that G719A seemed to already exist, although at much lower frequency as compared to wild type allele at this location. This preliminary results suggests that G719A is a pre-exist mutation in a small subset of LU1901 tumor cells which was rapidly selected out during c-MET TKI treatment. Our current working hypothesis is that this selection could be responsible for the resistance development. If our working hypothesis is eventually proven, it will provide a new important mechanism for the development of c-MET TKI resistancy that can occur in the clinic during MET based therapy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A91.

Citation Format: Mengmeng Yang, Jie Cai, Sheng Guo, Shijun Yu, Wubin Qian, Xiaoming Song, Youzhu Wang, Jean-Pierre Wery, Henry Li. Activating EGFR mutation, G719A, was selected in the c-MET amplified NSCLC-PDX-LU1901 during the treatments by c-MET inhibitors and the resistance development. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A91.
Abstract B10: Modeling the complexity of colorectal tumors in Drosophila.
Authors: Bangi Erdem , Murgia Claudio , Teague Alexander , Sansom Owen , Cagan Ross
Published: August 2014

The multigenic nature of human tumors presents a fundamental challenge for cancer research. To capture this genetic complexity we generated multigenic models of colon cancer in Drosophila—double, triple and quadruple combinations of transgenes representing mutations found together in sequenced human colon tumors. We then investigated the tumorigenic and metastatic potential of each of these combinations by targeting them specifically to the adult Drosophila colon as it shows important similarities to the human colon in terms of the signaling pathways that regulate its maintenance. We focused our initial analysis on three quadruple combinations: 1) rasG12V p53RNAi apcRNAi ptenRNAi, 2) rasG12V p53RNAi apcRNAi Smad4RNAi and 3) egfr p53RNAi apcRNAi Smad4RNAi. These models recapitulated key features of human cancer, including proliferation and multilayering of the colon epithelium, evasion of apoptosis and a senescence-like process, epithelial-mesenchymal-transition (EMT), migration and dissemination to distant sites within the body. Many tumor phenotypes arose as emergent properties of multigenic combinations. Using the dissemination phenotype of quadruple combination rasG12V p53RNAi apcRNAi ptenRNAi, as a quantitative read-out to monitor compound effects, we showed that multigenic models exhibit emergent resistance to a panel of clinically relevant compounds. We identified a mechanism of resistance for the PI3K/mTOR inhibitor BEZ235 and a combinatorial therapy that circumvents this resistance through a novel two-step process of emergent pathway dependence and suppression we term ‘induced dependence’. This approach proved effective in cultured human cancer cell lines, xenografts and a mouse model of colorectal cancer. Developing multigenic animal models that reference cancer genomes provides an effective approach for developing novel targeted therapies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B10.

Citation Format: Erdem Bangi, Claudio Murgia, Alexander Teague, Owen Sansom, Ross Cagan. Modeling the complexity of colorectal tumors in Drosophila. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B10.