bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4664: Co-targeting HGF-cMET signaling with MEK inhibitors in metastatic uveal melanoma
Authors: Cheng Hanyin , Kageyama Ken , Purwin Timothy , Liao Connie , Terai Mizue , Sato Takami , Aplin Andrew
Published: July 2016

Metastatic uveal melanoma (UM) patients usually die within one year, emphasizing an urgent need to develop new treatment strategies. Mitogen-activated protein kinase kinase (MEK) inhibitors improve survival in cutaneous melanoma patients but have limited efficacy in UM patients. Our previous work show that HGF-cMET signaling provides resistance to MEK inhibitors in metastatic UM cells. In this study, we further investigated the mechanisms of HGF-driven resistance to MEK inhibitors in metastatic UM cells. Cellular signaling pathway analysis was carried out to determine the role of downstream Bcl2 family members in overcoming trametinib-mediated apoptosis by HGF in metastatic UM cells. A new class of clinical grade cMET antibody and inhibitor were tested for their capacity to revert the resistance to trametinib mediated by HGF and tumor microenvironment. Selective inhibitors were utilized to determine the PI3K isoform dependency of metastatic UM cells in HGF-mediated protection against trametinib in metastatic UM cells. We demonstrate that the expression of two BH3-only family proteins, Bim-EL and Bmf, is upregulated in trametinib treated cells, but returns to basal levels upon HGF treatment in these cells. Targeting HGF-cMET signaling with LY2875358, a neutralizing and internalizing anti-cMET bivalent antibody, and LY2801653, a dual cMET/RON inhibitor overcomes resistance to trametinib provided by exogenous HGF and by conditioned medium from primary hepatic stellate cells. PI3Kβ-sparing inhibitor GDC0032 effectively blocks HGF-induced AKT phosphorylation and HGF-mediated resistance in trametinib treated cells in growth assays. In conclusion, our data suggest that HGF promotes resistance to MEK inhibitors through modulating Bim-EL and Bmf expression in UM cells. Our data also support the notion that selectively blocking PI3K isoform activities or cMET signaling may delay the onset of resistance to MEK inhibitors provided by tumor microenvironment in metastatic uveal melanoma.

Citation Format: Hanyin Cheng, Ken Kageyama, Timothy Purwin, Connie Liao, Mizue Terai, Takami Sato, Andrew Aplin. Co-targeting HGF-cMET signaling with MEK inhibitors in metastatic uveal melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4664.
Abstract 4668: Silencing PTGER3 enhances chemotherapeutic responses
Authors: Bayraktar Emine , Rodriguez-Aguayo Cristian , Mai Junhua , Ivan Cristina , Ivan Cristina , Chavez-Reyes Arturo , Sood Anil K. , Ferrari Mauro , Shen Haifa , Lopez-Berestein Gabriel
Published: July 2016

Inflammation is involved in the pathogenesis of cancer and inflammatory mediators such as prostaglandins (PGs) are abundantly present in the tumor microenvironment. Prostaglandin E(2) (PGE(2))-prostaglandin E2 receptor (EP)3 (PTGER3) signaling appears critical for tumor-associated angiogenesis, tumor growth and chemoresistance. However, the precise mechanism of this phenomenon in ovarian cancer remains unknown. In this study we hypothesized that down modulation of PTGER3 regulates drug resistance through the regulation of Ras-MAPK/Erk-Est-ELK1 axis in OC cells, resulting in decreased migration, proliferation and increased apoptosis. We analyzed a PTGER3 data set of OC patients from the Cancer Genome Atlas. Furthermore, the analysis of a panel of ovarian cancer cell lines showed that PTGER3 at mRNA and protein levels were higher in cisplatin-resistant cells when compared with their cisplatin sensitive counterparts. In vitro cell viability, growth, cell-cycle progression, migration, invasion and apoptosis, as well as in vivo therapeutic effectiveness in murine xenograft models, were also assessed following siRNA-mediated PTGER3 silencing in cisplatin-resistant ovarian cancer cells. The experimental validation identifies PTGER3 associated with OC survival. Significant inhibition of cell growth and viability, cell-cycle arrest, and activation of apoptosis were observed upon siRNA-mediated PTGER3 suppression. Furthermore, combination treatment with MSV/DOPC-siRNA-PTGER3 and cisplatin inhibited growth of A2780-CP20 tumors, which were otherwise resistant to cisplatin treatment. These findings identify PTGER3 as a potential therapeutic target in ovarian chemo-resistant cancers expressing high levels of this oncogenic protein.

Citation Format: Emine Bayraktar, Cristian Rodriguez-Aguayo, Junhua Mai, Cristina Ivan, Cristina Ivan, Arturo Chavez-Reyes, Anil K. Sood, Mauro Ferrari, Haifa Shen, Gabriel Lopez-Berestein. Silencing PTGER3 enhances chemotherapeutic responses. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4668.
Abstract 4670: Combinations of kinase siRNAs potentiates paclitaxel sensitivity in ovarian cancer
Authors: Yang Hailing , Wang Xiaoyan , Ahmed Ahmed , Iles Lakesla , Bartholomeusz Geoffrey , Lu Zhen , Bast Robert C.
Published: July 2016

Drug resistance imposes a major obstacle in ovarian cancer treatment. All patients with newly diagnosed ovarian cancer are treated with a combination of paclitaxel and carboplatin. While 70% of ovarian cancers respond to carboplatin, less than 50% respond to paclitaxel. Inhibition of kinases that modulate primary paclitaxel resistance, could enhance response to therapy. A Kinase siRNA library was screened in ovarian cancer cell lines to determine which kinases regulate paclitaxel sensitivity. Among 45 hits from high throughput screening, 14 target proteins (AATK, ACRBP, BMP2K, CHUK, EDN2, IKBKB, ILK, RAPGEF3, RAPGEF4, RFP, SIK2, STK24, STK39 and TBK1) regulated sensitivity to paclitaxel and were differentially expressed or overexpressed in a fraction of ovarian cancers. siRNAs against each of these kinases were tested for the ability to enhance sensitivity to paclitaxel in each of 12 ovarian cancer cell lines that reflected the heterogeneity observed in ovarian cancers including mutations of TP53, BRCA1/2, KRAS, BRAF, PI3K and PTEN. Knockdown of 10 individual genes enhanced paclitaxel sensitivity by at least two folds in different cell lines. A subscreen using combinations of these 14 kinase siRNAs in the six most responsive cell lines were carried out to select pairs of kinase siRNAs which could further potentiate paclitaxel sensitivity. IKBKB and STK39 kinase siRNAs had the greatest activity. We discovered that knockdown of IKBKB and STK39 stabilized microtubules judged by a microtubule fractionation assay and levels of acetylated and detyrosinated tubulin. IKBKB and STK39 kinase siRNAs also induced apoptosis. Double knockdown of microtubule stabilizing kinases IKBKB and STK39 resulted in greater enhancement in microtubule stability and apoptosis, leading to additive sensitization of paclitaxel. Small molecule inhibitors are available for IKBKB. As inhibition drugs become available for STK39, these observations can be translated to the clinic.

Citation Format: Hailing Yang, Xiaoyan Wang, Ahmed Ahmed, Lakesla Iles, Geoffrey Bartholomeusz, Zhen Lu, Robert C. Bast Jr.. Combinations of kinase siRNAs potentiates paclitaxel sensitivity in ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4670.
Abstract 4673: A novel way to sensitize pancreatic cancer cells for gemcitabine treatment
Authors: Xie Jingwu , Gu Dongsheng , Zhang Xiaoli , Jia Yanfei , Chiorean Gabi
Published: July 2016

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human malignancies, with a dismal median survival of 6 months. While combining albumin-bound paclitaxel with gemcitabine has shown clear therapeutic advantage, numerous attempts using novel targeted therapies did not yield clinical benefits. Gemcitabine is still the first-line treatment for patients with PDAC. We hypothesize that strategies to increase gemcitabine sensitivity may be effective in PDAC treatment. In this study, we report that cancer stem cell regulator Sox2 is highly induced in acquired gemcitabine resistant pancreatic cell lines, and down-regulation of Sox2 sensitizes cancer cells to gemcitabine treatment both in the cultured cells and in mouse models. Down-regulation of Gli1/2 was associated with reduced Sox2 expression, decreased expression of cancer stem cell markers. We found Gli1/2 proteins in association with a Sox2 promoter sequence with a putative Gli binding site, suggesting a direct regulation of Sox2 by Gli1/2. We further showed that down-regulation of Gli1 or Gli2 was as effective as Sox2 knockdown in sensitizing cancer cells to gemcitabine treatment. The relevance of Gli1/2-Sox2 signaling axis to PDAC was suggested by association of high Sox2 expression with poor survival in stage II PDAC patients. Taken together, our data indicate an important role of non-canonical hedgehog signaling in regulation of gemcitabine sensitivity, and down-regulation of Gli1/2 transcription factors, together with gemcitabine, may be effective in pancreatic cancer treatment.

Citation Format: Jingwu Xie, Dongsheng Gu, Xiaoli Zhang, Yanfei Jia, Gabi Chiorean. A novel way to sensitize pancreatic cancer cells for gemcitabine treatment. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4673.
Abstract 4678: Inhibition of CDK4 sensitizes multidrug resistant ovarian cancer cells to paclitaxel by increasing apoptosis
Authors: GAO YAN , Shen Jacson , Foster Rosemary , Hornicek Francis J. , Duan Zhenfeng
Published: July 2016

Purpose: Overexpression of cyclin-dependent kinase (CDK) 4 has been shown in a variety of cancers and contributes to tumor cell growth and proliferation. However, the effect of inhibition of CDK4 in ovarian cancer is unknown. Here we investigated the therapeutic effect of CDK4 inhibitor, palbociclib, in combination with paclitaxel in ovarian cancer cells. Experimental Design: Cell viability was determined by MTT assay after incubating with different dosages of palbociclib and/or paclitaxel. Western blot, immunofluorescence, and Calcein AM assays were conducted to determine the potential effects and mechanisms of palbociclib in combination with paclitaxel. CDK4 siRNA was used to validate the outcome of targeting CDK4 in ovarian cancer cells. Immunohistochemistry was performed to evaluate the clinical relevance of CDK4 expression in an ovarian cancer tissue microarray. Results: The combination of palbociclib and paclitaxel significantly enhanced drug sensitivity in both Rb positive (Rb+) and Rb negative (Rb-) ovarian cancer cells. Palbociclib suppressed the phosphorylation of pRb (Ser 807-811, Ser 795, and Ser 780) in multidrug resistant SKOV3TR (Rb+) cells. When combined with paclitaxel, palbociclib induced significant apoptosis in both SKOV3TR (Rb+) and OVCAR8TR (Rb-) cells. Palbociclib also inhibited the activity of P-glycoprotein (Pgp). Additionally, transfection of CDK4 siRNA showed effective knockdown of CDK4 expression and sensitized multidrug resistant SKOV3TR and OVCAR8TR cells to paclitaxel. Furthermore, primary ovarian cancer patients with high expression of CDK4 tended to have unfavorable clinical outcomes. Conclusions: Inhibition of CDK4 either by palbociclib or by specific siRNA can increase the in vitro paclitaxel sensitivity in either Rb+ or Rb- multidrug resistant ovarian cancer cells through increased apoptosis. Therefore, CDK4 may be a promising target in the treatment of ovarian cancer.

Citation Format: YAN GAO, Jacson Shen, Rosemary Foster, Francis J. Hornicek, Zhenfeng Duan. Inhibition of CDK4 sensitizes multidrug resistant ovarian cancer cells to paclitaxel by increasing apoptosis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4678.
Abstract 4680: Restoration of EGFR-TKI resistance by endocytosis inhibitor PAO in lung cancer with wild-type EGFR
Authors: Kim Boyeon , Sung Jae Sook , Kim Yeul Hong
Published: July 2016

Therapeutic efficacy of epithelial growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) is currently limited in selected lung cancer patients who have TKI sensitive EGFR mutation. However, the potential molecular mechanism that expands the therapeutic benefit of EGFT-TKI in patients who have wild-type EGFR non-small cell lung cancer (wtEGFR NSCLC) remains unclear. Recently, several studies revealed EGFR endocytosis mechanism could mediate signal transductions that influence in cancer cell proliferation. Moreover, our previous study demonstrated that EGFR endocytosis is related to gefitinib sensitivity in wtEGFR NSCLC and EGFR endocytosis could be a novel therapeutic target in lung cancer with wtEGFR (Oncotarget. 2014 15;5(5):1265-78). In this study, we investigated whether EGFR-TKI resistance could be restored in wtEGFR NSCLC cell lines by endocytosis inhibitor phenylarsine oxide (PAO). To investigate effects of PAO in vitro, we analyzed EGF-induced EGFR internalization and performed Annexin V and propodium iodide (PI) staining by flow cytometry. As a result, EGF-induced EGFR endocytosis is decreased and apoptotic cell death is induced accompanied by G0/G1 arrest after PAO treatment. In addition, we observed that cell viability is reduced significantly when PAO and EGFR-TKIs (gefitinib, erlotinib) treated together. Furthermore, we verified signaling transduction that associated with proliferation and apoptosis by western blot. To confirm combination effects of PAO and EGFR-TKI in vivo, we established xenograft mouse model using gefitinib-insensitive SNU1327 cell lines. After Tumor sizes reached 100-200mm3, mice were treated with PAO or gefitinib alone, or combined treatment for 3 weeks. We observed that tumor sizes of combination group were more decreased than other groups.In these result, we validate endocytosis inhibitor PAO is potential drug for overcoming therapeutic limitation of EGFR-TKI in gefitinib-insensitive wtEGFR NSCLC cell lines, though further experiment is needed to explain more accurate mechanism. This study was supported by a Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2013R1A1A2057538).

Citation Format: Boyeon Kim, Jae Sook Sung, Yeul Hong Kim. Restoration of EGFR-TKI resistance by endocytosis inhibitor PAO in lung cancer with wild-type EGFR. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4680.
Abstract 4684: Modulating the function of multidrug resistance ABCG2 transporter by tyrosine kinases receptor inhibitor cabozantinib
Authors: Zhang Guannan , Zhang Yun-Kai , Wang Yi-Jun , Chen Zhe-Sheng
Published: July 2016

Cabozantinib (XL184) is an oral tyrosine kinases receptor inhibitor which inhibits MET and vascular endothelial growth factor receptor 2 (VEGFR2). Cabozantinib has been approved by Food and Drug Administration for treating advanced medullary thyroid cancer and it is also tested in clinical trials on other solid tumors, including prostate, bladder, ovarian and breast cancer. In the present study, we evaluated the ability of cabozantinib in modulating the function of ABCG2 transporter in drug-selected H460/MX20 cell line and ABCG2 stable transfected cell lines ABCG2-482-R2, ABCG2-482-G2 and ABCG2-482-T7. Cabozantinib at non-toxic level can sensitize the ABCG2-overexpressing cells to antineoplastic drugs mitoxantrone, SN-38 and topotecan. Our results indicated that cabozantinib reversed ABCG2 mediated multi-drug resistance by antagonizing the drug efflux function of ABCG2. However, this reversal effect was not attributed to reduced expression of ABCG2 protein, because ABCG2 protein level was unchanged after treatment of 4μM cabozantinib for 72 hours. Immunofluorescence result showed that cabozantinib did not alter the cellular localization of ABCG2 transporter. Docking analysis indicated that cabozantinib binds to the drug-binding site of ABCG2 transporter. Finally, cabozantinib at 4μM did not significantly change the resistance of ABCB1 overexpressing cell line SW620/AD300 to antineoplastic drug paclitaxel. Overall, our finding demonstrated that cabozantinib potentiates the cytotoxic effects of various antineoplastic drugs that are substrates of ABCG2 and that this is due to modulating the function of ABCG2 transporter.

Keyword: Cabozantinib; ABCG2; Multidrug resistance;

Citation Format: Guannan Zhang, Yun-Kai Zhang, Yi-Jun Wang, Zhe-Sheng Chen. Modulating the function of multidrug resistance ABCG2 transporter by tyrosine kinases receptor inhibitor cabozantinib. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4684.
Abstract 4685: Metformin enhances trastuzumab efficacy for HER2+ gastric cancer cells
Authors: Kim Jin-Soo , Kim Geum Ock , Kim Mi Young
Published: July 2016

Background: Trastuzumab is an effective monoclonal antibody against advanced gastric cancers (GCs) with HER2 amplification. Recently, HER2 directed therapies, such as pertuzumab or lapatinib are actively investigated in clinical trials, but showed disappointing results in patients with HER2+ GC. Unfortunately, the efficacy of trastuzumab is limited due to primary and acquired resistance to this agent. Metformin is a widely used antidiabetic drug and shows promising anti-tumor effect in several cancers.

Material and Methods: The following GC cells were evaluated: HER2 amplification -positive (HER2+) and trastuzumab-sensitive NCI-N87 and OE19, HER2+ trastuzumab-resistant OE33 and HER2 negative AGS, H1750 and SNU601. We assessed response of these GC cells to trastuzumab alone or in combination with metformin by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay and anchorage independent growth in soft agar. MGI (mean growth inhibition) was calculated by dividing the colony number of the treated group by that of the untreated control group. Western blots were performed to assess biochemical changes, especially those related with HER2 signaling components.

Results: We observed that treatment with trastuzumab in combination with metformin induced a statistically significant decrease in the number of colonies formed in soft agar by N87 and OE19 cells, as compared to the numbers formed by control cells or cells in the single-treatment groups (Kruskal-Wallis test, p = 0.025, respectively). No growth inhibitory effect was detected in OE33 cells with Compared to trastuzumab alone, the combination of metformin resulted in decreased phosphorylation of HER2 and downstream targets, such as AKT or ERK, in trastuzumab-sensitive HER2+ cells.

Conclusion: Collectively, these data support that trastuzumab and metformin are synergistic in trastuzumab-sensitive HER2+ GC cells. Combination effect on soft agar colony forming assaysCell LinesTrastuzumabMetforminCombinationIndexMGIPMGIPExpectedObservedPNCI-N870.8000.0210.8160.0310.6530.607<0.0011.077OE190.6000.0050.5650.0030.3390.152<0.0012.234OE330.9250.6770.8230.1030.7610.9000.4700.846

Citation Format: Jin-Soo Kim, Geum Ock Kim, Mi Young Kim. Metformin enhances trastuzumab efficacy for HER2+ gastric cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4685.
Abstract 4693: Mechanism-based combination strategies for BET inhibitors in NUT midline carcinoma
Authors: Wyce Anastasia , Soden Peter , Felitsky Daniel J. , Matteo Jeanne J. , Korenchuk Susan , Thripp Gary , Keenan Kathryn , McHugh Charles F. , Prinjha Rab , Carpenter Christopher , Smithers Nicholas , Barbash Olena
Published: July 2016

NUT midline carcinoma (NMC) is a highly aggressive squamous cell cancer that responds poorly to standard chemotherapuetic approaches. NMC is characterized by translocations involving the NUT (nuclear protein in testes) protein, which in a majority of cases is fused to the BET (bromodomain and extra-terminal) protein family members BRD3 or BRD4. BET proteins (BRD2, BRD3, BRD4, BRDT) are epigenetic readers that modulate expression of genes involved in cell growth and oncogenesis. Selective small molecule inhibitors of BET proteins, such as the GSK I-BETs (I-BET762, I-BET151), abrogate binding of BET proteins to acetylated chromatin and inhibit the expression of BET target genes. Here we describe the activity in I-BET762 and other BET inhibitors in pre-clinical models of NMC. Consistent with previous reports, we observe profound growth inhibition and cytotoxicity in NMC cell lines in vitro, as well as significant tumor growth inhibition or tumor regression in cell line xenografts of NMC. I-BET762 treatment in NMC cell lines results in transcriptional changes affecting MYC and other pathways critical for cancer cell growth. We explore the contribution of these changes to the anti-proliferative effects observed in NMC models, and identify rational combinations to improve upon the efficacy of I-BET762 as a monotherapy. Taken together, our data highlight novel mechanisms through which BET inhibitors impact NMC cell growth and survival, and suggest potential treatment strategies to improve response in this highly aggressive disease. All studies were conducted in accordance with the GSK Policy on the Care, Welfare and Treatment of Laboratory Animals and were reviewed by the Institutional Animal Care and Use Committee either at GSK or by the ethical review process at the institution where the work was performed.

Citation Format: Anastasia Wyce, Peter Soden, Daniel J. Felitsky, Jeanne J. Matteo, Susan Korenchuk, Gary Thripp, Kathryn Keenan, Charles F. McHugh, Rab Prinjha, Christopher Carpenter, Nicholas Smithers, Olena Barbash. Mechanism-based combination strategies for BET inhibitors in NUT midline carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4693.
Abstract 4706: ABBV-075 exhibits robust in vitro and in vivo activities against the ABC and GCB subtypes of DLBCL
Authors: Lin Xiaoyu , Huang Xiaoli , Sarthy Aparna , Magoc Terry , Albert Daniel , Lam Lloyd , Uziel Tamar , Lu Xin , Bui Mai-Ha , Faivre Emily , Wilcox Denise , Elmore Steven , McDaniel Keith , Kati Warren , Shen Yu
Published: July 2016

Diffuse Large B-Cell Lymphoma (DLBCL) consists of activated B-cell-like (ABC), germinal center B cell-like (GCB), and primary mediastinal B cell lymphoma (PMBL) subtypes. Among these, the ABC subtype of DLBCL often harbors mutations that cause abnormal NF-κB activation, which subsequently activates genes important for cell survival and disease progression in ABC DLBCL. The bromodomain and extraterminal domain (BET) protein BRD4 binds acetylated NF-κB and regulates NF-κB dependent transcription. Accordingly, targeting BET family proteins using small molecule inhibitors such as ABBV-075 might provide therapeutic benefit in ABC DLBCL by blocking the NF-κB pathway. In this study, we examined the activity of ABBV-075 in both the ABC and GCB subtypes of DLBCL. As expected, ABBV-075 diminished NF-κB reporter activity, down-regulated NF-κB target genes, inhibited proliferation and survival of ABC DLBCL cells in vitro, and delayed the growth of ABC DLBCL tumors in vivo. Interestingly, ABBV-075 also exhibited robust anti-proliferative activities in GCB DLBCL cells in vitro and inhibited the growth of GCB DLBCL tumors in vivo. Further characterization of the responses of GCB DLBCL cells to ABBV-075 indicated that ABBV-075 induced strong apoptosis in GCB DLBCL cells that are resistant to the Bcl-2 inhibitor venetoclax (ABT-199), but rarely in venetoclax-sensitive GCB DLBCL cell lines. Our results indicate that ABBV-075 could be active against both the ABC and GCB subtypes of DLBCL. The complementary activity of ABBV-075 and ABT-199 further suggests that ABBV-075 maybe an interesting option for ABT-199 resistant/refractory DLBCL patients.

Citation Format: Xiaoyu Lin, Xiaoli Huang, Aparna Sarthy, Terry Magoc, Daniel Albert, Lloyd Lam, Tamar Uziel, Xin Lu, Mai-Ha Bui, Emily Faivre, Denise Wilcox, Steven Elmore, Keith McDaniel, Warren Kati, Yu Shen. ABBV-075 exhibits robust in vitro and in vivo activities against the ABC and GCB subtypes of DLBCL. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4706.
Abstract 4709: Broad activity for the combination of BET and MEK inhibitors across solid and hematologic cancers
Authors: Wyce Anastasia , Felitsky Daniel J. , Zhang Xi-Ping , Matteo Jeanne J. , Korenchuk Susan , Mathew Lijoy K. , Musso Melissa , Khaku Sakina , Ortiz Victoria , Keenan Kathryn , Stern Melissa , Degenhardt Yan , Plant Ramona , McHugh Charles F. , Tummino Peter J. , Carpenter Christopher , Barbash Olena
Published: July 2016

BET (bromodomain and extra-terminal) family proteins are epigenetic readers that modulate expression genes involved in cell growth and oncogenesis. Selective small molecule BET inhibitors, such as the GSK I-BETs (I-BET762, I-BET151), abrogate binding of BET proteins to acetylated chromatin and inhibit transcription of BET target

genes. We and others have previously demonstrated single agent activity for BET inhibitors in a number of pre-clinical solid and hematologic tumor models. Transcriptomics

and mechanistic studies from several of these tumor types indicate that BET inhibitors influence numerous signaling pathways at the transcriptional level, including RAS/RAF/MEK signaling. Here we describe the synergistic effects of combining BET and MEK inhibitors in various solid and hematologic cancer models. We observe synergistic growth inhibition and apoptosis in a subset of cell lines representing multiple tumor types, as well as patient-derived xenograft models treated with the combination ex vivo. Additionally, combination of BET and MEK inhibitors results in improved tumor growth inhibition in cell line xenograft models compared to either single agent therapy. Further exploration of the combination in sensitive tumor types highlights multiple mechanisms potentially driving synergy, and suggests possible markers associated with sensitivity to the combination. Taken together, our data highlight the potential of BET/MEK inhibitor combinations to improve upon the efficacy observed for these agents as monotherapies in a wide variety of preclinical cancer models.

All studies were conducted in accordance with the GSK Policy on the Care, Welfare and Treatment of Laboratory Animals and were reviewed by the Institutional Animal Care and Use Committee either at GSK or by the ethical review process at the institution where the work was performed. Human biological samples were sourced ethically and their research use was in accord with the terms of the informed consents.

Citation Format: Anastasia Wyce, Daniel J. Felitsky, Xi-Ping Zhang, Jeanne J. Matteo, Susan Korenchuk, Lijoy K. Mathew, Melissa Musso, Sakina Khaku, Victoria Ortiz, Kathryn Keenan, Melissa Stern, Yan Degenhardt, Ramona Plant, Charles F. McHugh, Peter J. Tummino, Christopher Carpenter, Olena Barbash. Broad activity for the combination of BET and MEK inhibitors across solid and hematologic cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4709.
Abstract 4711: Broad anti-tumor activity of a novel BET bromodomain inhibitor
Authors: Ma Yan , Powell Ben , Zhang Jiazhong , Zhang Ying , Carias Heidi , Schwertschlag Ullrich , Habets Gaston , Ibrahim Prabha , Spevak Wayne , Zhang Chao , Bollag Gideon
Published: July 2016

Inhibitors against the bromodomain and extra terminal domain (BET) family of proteins have been pursued as promising oncology agents based on growing understanding of epigenetic control of disease processes. Through scaffold-based and crystallography-guided drug design, we discovered PLX51107, a potent and selective small molecule inhibitor of the BET family bromodomains. PLX51107 is structurally unrelated to the benzodiazepines such as JQ1, I-BET762, and OTX015 and other published BET inhibitors. PLX51107 exhibits low nanomolar potency in blocking interactions mediated by the four BET family proteins BRD2, BRD3, BRD4, and BRDT. Pharmacologic inhibition of BET proteins by PLX51107 suppresses the transcription of genes essential for tumor growth and survival and leads to selective killing of cancer cell lines across a broad range of hematologic malignancies (e.g. leukemia, lymphoma and multiple myeloma). A subset of solid tumors (e.g. melanoma and SCLC) is also sensitive to growth inhibition by the BET inhibitor PLX51107. Novel biomarkers in these diseases have been identified. PLX51107 is well tolerated and has sufficient potency and oral bioavailability to demonstrate in vivo efficacy in animal models of a variety of tumor types, representing both hematologic and solid tumors of diverse genetic backgrounds. In combination studies, PLX51107 showed potential to improve the efficacy (response rates and duration of response) of other anticancer treatments without increased toxicity. These results support further development of PLX51107 as an epigenetic-based therapy for a variety of cancer indications.

Citation Format: Yan Ma, Ben Powell, Jiazhong Zhang, Ying Zhang, Heidi Carias, Ullrich Schwertschlag, Gaston Habets, Prabha Ibrahim, Wayne Spevak, Chao Zhang, Gideon Bollag. Broad anti-tumor activity of a novel BET bromodomain inhibitor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4711.
Abstract 4728: Histone deacetylase inhibitors induce apoptosis in multiple tumor types through induction of ATF3
Authors: Chueh Anderly C. , Tse Janson , Ioannidis Paul , Tögel Lars , Tan Bee S. , Davlos-Salas Mercedes , Nightingale Rebecca , Thompson Matthew R. , Williams Bryan , Dickinson Michael , Dhillon Amardeep S. , Mariadason John M.
Published: July 2016

Histone deacetylase inhibitors (HDACi) are approved for the treatment of cutaneous T-Cell lymphoma (CTCL) and Multiple Myeloma. In colon cancer cells HDACi-induced apoptosis is linked to induction of a specific transcriptional response involving upregulation of the immediate-early (IE) response genes FOS, JUN, EGR1, EGR3 and ATF3. To determine if this transcriptional response underpins HDACi-induced apoptosis across multiple tumour types, including CTCL and MM, 50 cell lines derived from common solid and haematological cancers were screened for sensitivity to HDACi-induced apoptosis, and response correlated with IE gene induction. HDACi treatment robustly induced IE gene mRNA and protein expression in multiple tumour lines. IE gene induction was sustained over 24 hours and dependent on the Sp1/Sp3 transcription factors and was also observed in vivo in CTCL patients treated with the HDACi panobinostat. The magnitude of induction of FOS, JUN and ATF3 expression correlated significantly with HDACi-induced apoptosis. The induction of ATF3 was critical for HDACi induced apoptosis as ATF3 downregulation markedly attenuated HDACi-induced apoptosis in multiple tumour lines, and ATF3 knockout MEFs were refractory to HDACi-induced apoptosis. To identify downstream targets of ATF3, the magnitude of ATF3 induction following HDACi treatment was correlated with altered expression of pro and anti-apoptotic genes involved in the intrinsic apoptotic pathway. The magnitude of ATF3 induction correlated inversely with repression of the anti-apoptotic gene Bcl-XL, and ATF3 knockdown attenuated HDACi-mediated Bcl-XL repression. Notably, combinatorial treatment of refractory cell lines with an HDACi and a Bcl-XL inhibitor significantly enhanced HDACi-induced apoptosis. This study demonstrates that IE gene induction is a universal feature of HDACi-induced apoptosis, and that ATF3 as a key driver of HDACi-induced apoptosis through repression of Bcl-XL. These findings establish a method for rapid assessment of HDACi response, and identify a combination strategy for enhancing the activity of these compounds.

Citation Format: Anderly C. Chueh, Janson Tse, Paul Ioannidis, Lars Tögel, Bee S. Tan, Mercedes Davlos-Salas, Rebecca Nightingale, Matthew R. Thompson, Bryan Williams, Michael Dickinson, Amardeep S. Dhillon, John M. Mariadason. Histone deacetylase inhibitors induce apoptosis in multiple tumor types through induction of ATF3. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4728.
Abstract 4732: A novel analog of Leonurine inhibits melanoma growth and survival through STAT3 signaling pathways
Authors: Pandey Manoj K. , Krzeminski Jacek , Karelia Deepkamal , Sharma Arun K. , Amin Shantu G.
Published: July 2016

Previous studies have shown that a major alkaloid of Leonurus japonicus Houtt, Leonurine, displays a variety of biological effects including inhibition of HMG-CoA reductase, kidney fibrosis, and osteoporosis. However, the full potential of this alkaloid as a cancer therapeutics has not been explored, primarily due to the lack of potency. A limited reports however, do suggest that Leonurine induces apoptosis in lung and liver cancer cells. We hypothesized that this natural product's structure can be optimized to create a more potent and drug-like molecule. A recent structure-activity relationship (SAR) study in our laboratory based on Leonurine structure has led to the identification of three novel analogs which were >100 times potent than Leonurine in killing solid cancer cells. The aim of the current study is to determine whether the novel analogs of Leonurine exhibit anti-proliferative effects against tumor cells through suppression of the signal transducer and activator of transcription 3 (STAT3) activation pathway. We investigated the effects of Leonurine analogs on constitutive STAT3 activation, modulation of tyrosine kinases and phosphatases in STAT3 activation, STAT3-regulated gene products, and growth modulation of tumor cells. We found that these compounds inhibited constitutive STAT3 activation in metastatic melanoma cells. The suppression was mediated through the inhibition of activation of the upstream kinases Janus-like kinase (JAK) 1, and JAK2. Leonurine derivatives down-regulated the expression of STAT3-regulated gene products such as survivin, Bcl-xL, Bcl-2, cyclin D1, and Mcl-1 leading to the suppression of proliferation and induction of apoptosis. Moreover, we found that these Leonurine analogs significantly inhibited the proliferation of variety of cells derived from solid tumors including breast, pancreatic, prostate, and colon cancer. Overall, these results suggest that these new compounds are novel blockers of STAT3 activation and thus may have potential to suppress melanoma cell proliferation and chemoresistance.

Citation Format: Manoj K. Pandey, Jacek Krzeminski, Deepkamal Karelia, Arun K. Sharma, Shantu G. Amin. A novel analog of Leonurine inhibits melanoma growth and survival through STAT3 signaling pathways. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4732.
Abstract 4739: The upregulation of cyclooxygenase-2 protein expression by receptor tyrosine kinase inhibitors in bladder cancer in vitro
Authors: Bourn Jennifer , Cekanova Maria
Published: July 2016

Several types of cancer, including transitional cell carcinoma (TCC) overexpress several receptor tyrosine kinases (RTKs), including the platelet-derived growth factor receptor (PDGFR), c-kit receptor, epidermal growth factor receptor (EGFR), as well as the vascular endothelial growth factor receptor (VEGFR). Receptor tyrosine kinase inhibitors (RTKIs) are used as targeted therapies for patients diagnosed with cancer with high expression of RTKs. Cyclooxygenase-2 (COX-2) is highly expressed in bladder cancer as well other types of cancers and is one of the key proteins during tumorigenesis. In this study, we validated the effects of RTKIs, Masitinib® (AB1010) and Axitinib on cell proliferation of human (UMUC-3 and T24) and canine (K9TCC#1Lillie, K9TCC#2Dakota, and K9TCC#5Lilly) bladder TCC cells. Using WB analysis, tested human and canine TCC cells, except T24 cells, expressed PDGFR and c-kit receptors. There was no detectable EGFR and VEGFR expressions in any of tested cells by WB analysis. The K9TCC#1Lillie and K9TCC#5Lilly cells had a high expression of COX-2, however K9TCC#2Dakota and human T24 had moderate expression of COX-2, and no COX-2 expression was detected in UMUC3 cells by WB analysis. Both RTKIs, Masitinib® and Axitinib inhibited cell proliferation of the tested human and canine bladder TCC cells in a dose-dependent manner by MTS and apoptosis assays. Interestingly, both tested RTKIs, Masitinib® and Axitinib increased COX-2 protein expressions in tested canine TCC cells. Combined treatment of RTKIs with COX-2 inhibitors decreased cell proliferation of tested TCC cells more effectively as either treatments alone. Our results indicate a possible role of COX-2 signaling pathway in developed RTKIs-resistance in bladder cancer cells in vitro. Co-treatment of RTKIs with COX-2 inhibitors might indicate better clinical outcomes in treatments of patients diagnosed with bladder cancer.

Citation Format: Jennifer Bourn, Maria Cekanova. The upregulation of cyclooxygenase-2 protein expression by receptor tyrosine kinase inhibitors in bladder cancer in vitro. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4739.
Abstract 4744: Targeting nitric oxide signaling with nNOS inhibitors as a novel strategy for the therapy and prevention of human melanoma
Authors: YANG SUN , Yang Zhen , Silverman Richard B. , Poulos Thomas , Meyskens Frank L.
Published: July 2016

The incidence of cutaneous melanoma (CM) has increased markedly over the past four decades although there have been some dramatic advances recently in the treatment of advanced melanoma. The development of novel therapeutic interventions blocking melanoma progression would be of high impact. Recently, our group has identified that neuronal NO synthase (nNOS) activated by UV radiation and growth factor plays an important role in melanoma progression, in parallel with generating constitutive NO stress. Knockdown of nNOS significantly reduced tumor growth and lung metastasis in vivo.

The newly developed nNOS inhibitors HHs (HH044 and HH045) exhibited potent anti-melanoma activity both in vitro and in vivo. The IC50s of HH compounds in human melanoma cells are less than 10 μM, which are comparable or even better than that of chemotherapeutic drug cisplatin (4.2μM and 14.3μM in A375 and Sk-Mel28 cells, respectively). Notably, the inhibition by HHs is more predominant in metastatic melanoma A375 cells compared to primary early stage Wm3211 cells, which supports our hypothesis that nNOS/NO signaling is more critical to melanoma progression than in the initiation phase. In a melanoma xenograft tumor model, we further determined the effects of HH044 and HH045 in tumor growth in vivo. Treatments with HH044 and HH045 (50mg/kg i.p for 21 days) significantly reduced the tumor size to 12% and 19% of control respectively with no apparent systematic toxicities observed. The body weight in treated mice was even moderately higher than the control’s. Taken together, these results are consistent with our hypothesis that targeting nNOS is an efficient and practicable approach for human melanoma therapy.

Citation Format: SUN YANG, Zhen Yang, Richard B. Silverman, Thomas Poulos, Frank L. Meyskens. Targeting nitric oxide signaling with nNOS inhibitors as a novel strategy for the therapy and prevention of human melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4744.
Abstract 4749: Bromodomain inhibition of the transcriptional coactivators CBP/EP300 as a therapeutic strategy to target the IRF4 network in multiple myeloma
Authors: Keller Patricia J. , Conery Andrew R. , Centore Richard C. , Bommi-Reddy Archana , Gascoigne Karen E. , Bryant Barbara M. , Mertz Jennifer A. , Sims Robert J.
Published: July 2016

Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. We demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Selective targeting of multiple myeloma cell lines through CBP/EP300 bromodomain inhibition is the result of direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4, which is essential for the viability of myeloma cells, and the concomitant repression of the IRF4 target gene c-MYC. Ectopic expression of either IRF4 or MYC antagonizes the phenotypic and transcriptional effects of CBP/EP300 bromodomain inhibition, highlighting the IRF4/MYC axis as a key component of its mechanism of action. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network.

Citation Format: Patricia J. Keller, Andrew R. Conery, Richard C. Centore, Archana Bommi-Reddy, Karen E. Gascoigne, Barbara M. Bryant, Jennifer A. Mertz, Robert J. Sims. Bromodomain inhibition of the transcriptional coactivators CBP/EP300 as a therapeutic strategy to target the IRF4 network in multiple myeloma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4749.
Abstract 4759: Identification of ALK, ROS1, FGFR2 and NRG1 fusions and validation with targeted inhibitors in lung and ovarian PDX models
Authors: Tang Xuzhen , Dong Hua , Gao Yibo , Zhang Zhixiang , Qiang Xiangnan , Zhang Baoyuan , Qin Yuxin , Yang Shuqun , Yan Yunbiao , Gu Qingyang , Zhang Norman , He Jie , Ji Qunsheng
Published: July 2016

Chromosomal rearrangement mediated gene fusions and activation of oncogenic signaling pathways have become druggable targets for therapeutic intervention, with successful development of Imatinib as an inhibitor of Bcr-Abl in treatment of Philadelphia chromosome positive chronic myelogenous leukemia. A recent study by Stransky et. al. reported systemic analysis of the transcriptome of nearly 7000 human tumor samples from the Cancer Genome Atlas and revealed the landscape of near twenty kinase fusions across twenty solid tumor types. Identification of corresponding PDX models that carry given kinase fusions would be of paramount interest for preclinical validation of candidate inhibitors. We have established about 1000 PDX models across 20 tumor types. Here we report the identification of ALK, ROS1, FGFR2 fusions in lung cancer PDX models and a NRG1 fusion in the ovarian cancer models by RNA using Sequencing data combined with the Chimerascan and Star-Fusion software for fusion calling.. The gene fusions, as validated by PCR and Sanger Sequencing, led to over-expression of the affected kinases, supporting the notion that kinase activation may be the oncogenic driver in the corresponding tumors. We further validated that ALK inhibitors Crizotinib, AP26113 and LDK378 exhibited robust antitumor activities in the ALK fusion model. Current works on validation of ROS1, FGFR2 and NRG1 inhibitors in the pertinent fusion models are under progression. These models should provide means for pre-clinical validation of novel kinase inhibitors and for experimenting novel combinatorial therapeutic strategies.

Citation Format: Xuzhen Tang, Hua Dong, Yibo Gao, Zhixiang Zhang, Xiangnan Qiang, Baoyuan Zhang, Yuxin Qin, Shuqun Yang, Yunbiao Yan, Qingyang Gu, Norman Zhang, Jie He, Qunsheng Ji. Identification of ALK, ROS1, FGFR2 and NRG1 fusions and validation with targeted inhibitors in lung and ovarian PDX models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4759.
Abstract 4766: Establishment of drug sensitivity and resistance testing using focused drug libraries to develop targeted therapies for patients with leukemia
Authors: Patel Apurvi , Montoya Justin J. , Wai Daniel H. , Arceci Robert J. , Azorsa David O.
Published: July 2016

Despite major advancements in pediatric leukemia therapy, toxicities and morbidity from chemotherapy regimens have been detrimental. Advances in genomic research as well as precision medicine have helped identify specific mutations that may be susceptible to targeted therapy in leukemic patients. Overall, the use of targeted drug therapy is rising in the pediatric oncology field. To complement genomic analysis of leukemia patients, our laboratory is working on the development of a drug sensitivity and resistance screening library, that would provide functionally relevant drug response data of the patient's leukemia cells. Development of this assay included the preparation of pre-dosed library plates allowing for rapid initiation of the assay. Cells were treated for 72 hours and cell viability was determined. Preliminary work in our laboratory used a library of 56 anti-cancer and targeted agents, which were tested on 16 AML cell lines and 10 ALL cell lines. Biological replicates were preformed for each cell line and drug response data in the form of IC50s and Area Under the Curve (AUC) were calculated. Hierarchical clustering was performed to determine similar responses between cell lines. Our results identified several cell lines that showed hypersensitivity to specific drugs. Among them, the AML cell line KG-1a showed sensitivity to three FGFR inhibitors including Ponatinib, which was previously reported. Validation of the screening results was done using a 10-concentration drug dose response assay. Further testing will include expansion of our drug library and application to ex vivo patient samples. The results from these studies can lead to the establishment of a drug sensitivity and resistance assay that could provide specifically engineered therapies for each patient. This form of personalized therapy would lead to diminished toxicities from systemic therapies as well as allow increased cure rates.

Citation Format: Apurvi Patel, Justin J. Montoya, Daniel H. Wai, Robert J. Arceci, David O. Azorsa. Establishment of drug sensitivity and resistance testing using focused drug libraries to develop targeted therapies for patients with leukemia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4766.