bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2575: EZH2 mediates resistance to cisplatin in small cell lung cancer through nucleotide excision repair
Authors: Koyen Allyson E.
Published: August 2019

Small cell lung cancer (SCLC) is the most aggressive form of lung cancer, with a five-year survival rate of 7%. Cisplatin-based chemotherapy is the first line treatment for SCLC; however, many patients develop treatment resistance and experience tumor recurrence. Targeting proteins critical to the repair of cisplatin DNA crosslinks is a strategy for overcoming acquired cisplatin resistance in SCLC, but many proteins that mediate crosslink repair have yet to be identified. To address this issue, we performed a synthetic lethal siRNA screen in cisplatin resistant SCLC cells, and identified EZH2 as one of the strongest mediators of cisplatin resistance. EZH2 localizes to sites of DNA damage which are induced by UVA-crosslinking laser microirradiation and interacts in a complex with DDB1, and DDB2, members of the nucleotide excision repair (NER) pathway. Loss of EZH2 sensitizes SCLC cells to UV damage, and further, loss of EZH2 and DDB1 together are epistatic in the sensitization of SCLC to cisplatin, confirming a role for EZH2 in NER. Specifically, EZH2 promotes the stability of DDB2, which is responsible for the detection NER lesions. This occurs independently of EZH2’s methyltransferase activity on H3K27. Finally, we found EZH2 expression correlates with cisplatin resistance across SCLC cell lines. Together, this data suggests that EZH2 functions as a novel regulator of NER, and that EZH2 is a promising target for cisplatin resistant SCLC.

Citation Format: Allyson E. Koyen. EZH2 mediates resistance to cisplatin in small cell lung cancer through nucleotide excision repair [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2575.
Abstract 2589: A systematic study on the anti-tumor effect of combinatorial miRNA expression in hepatocellular carcinoma
Authors: Xu Feng , Tong Man , Ma Stephanie , Wong Alan SL
Published: August 2019

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer mortality worldwide. Treatment options for HCC patients are limited, especially for those with advanced HCC. Deregulation of microRNA (miRNA) expression is frequently observed in HCC, and many cellular targets of miRNAs are genetic regulators of tumorigenesis. In addition, miRNAs interact with each other to coordinate targeted gene expressions. The potential of devising combinatorial miRNA-based therapies for HCC, however, remains largely unexplored. Here, we performed high-throughput CombiGEM screens to characterize the anti-tumorigenic effect of combinatorial miRNA expression. We assembled a library of 1,849 pairwise combinations for 43 human miRNAs that are downregulated in HCC patients/cell lines, and identified four miRNA combinations that exert anti-proliferative effect in HCC cells both in vitro and in vivo. Further experiments are underway to validate and characterize the anti-tumor effect of these newly identified miRNA combinations in HCC.

Citation Format: Feng Xu, Man Tong, Stephanie Ma, Alan SL Wong. A systematic study on the anti-tumor effect of combinatorial miRNA expression in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2589.
Abstract 259: Interplay between Bcl-2 and cFLIP in lymphoma disease progression is a function of an altered redox milieu
Authors: Hirpara Jayshree L. , Pervaiz Shazib
Published: August 2019

Bcl-2 is associated with chemoresistance and despite the preponderance of evidence linking its anti-apoptotic function to hematologic cancers, it’s now emerging that overexpression of Bcl-2 is a feature shared by a host of cancers. Canonically, the death inhibitory activity of Bcl-2 is associated with its ability to prevent mitochondrial outer membrane permeabilization. However, recent evidence has highlighted a novel facet in the biology of Bcl-2, whereby enforced expression of Bcl-2 resulted in an increase in mitochondrial oxygen consumption and elevated levels of the reactive oxygen species (ROS), superoxide (O2-.). Alleviating the levels of intracellular O2-. sensitized Bcl-2 overexpressing cells to death receptor induced apoptosis via a robust increase in upstream caspase 8 activation. Using a variety of functional mutants of the NOX-activating small GTPase Rac1, we show a clear link between Bcl-2 induced apoptosis resistance and intracellular O2-.. In the search for the molecular target of this inhibitory signal, we now show that Bcl-2 overexpression is associated with an increase in the transcription and protein levels of the receptor inhibitory protein, cFLIP. We employed pharmacological and genetic approaches to modulated intracellular O2-. and present evidence cFLIP is transcriptionally regulated by O2-.; increase in cFLIP promoter activity and mRNA levels. Interestingly, inhibiting glycolysis also resulted in downregulation of cFLIP in a ROS-dependent manner. Notably, primary cells derived from patients with lymphoma also showed a significant downregulation of cFLIP when subjected to conditions that decrease O2-. and elicited enhanced sensitivity to TRAIL-induced apoptosis. Importantly, TCGA and Affy meta-cohorts’ analyses revealed consistent correlation trend: Bcl-2 and cFLIP (CFLAR) were positively correlated; Bcl-2 and SOD1 (superoxide dismutase 1) were negatively correlated. A strong negative correlation was also observed between CFLAR and SOD1. Furthermore, Kaplan-Meier analyses of overall survival (OS) were performed in the in-house High expression of either Bcl-2 or CFLAR conferred poor OS outcome. When stratified by CFLAR and Bcl-2 expressions, cases with higher expression of the two genes had the worst prognosis with the shortest median survival. Notably, DLBCL with high Bcl-2 and low SOD1 had the worst OS outcome, compared against expression levels of Bcl-2 and SOD1. Together, these findings point to a concordance between cFLIP and Bcl-2, which negatively correlates with SOD1 in driving lymphoma progression.

Citation Format: Jayshree L. Hirpara, Shazib Pervaiz. Interplay between Bcl-2 and cFLIP in lymphoma disease progression is a function of an altered redox milieu [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 259.
Abstract 2590: Nano-exosomes with miRNA: A new therapeutic approach
Authors: Kuppa Sudeepti , Rada Balazs , Roberts Arthur , Murph Mandi M.
Published: August 2019

Access to reliable and effective therapeutics for patients suffering from aggressive triple-negative breast cancer (TNBC) has been clinically challenging to achieve due to lack of targetable mutations and high heterogeneity in the tumor cells. Therapeutic approaches to reduce mortality in the TNBC patient subset requires an innovative and targeted approach to drug delivery, which is presented here in the form of labeled-exosomes. In this study, we have developed a novel method to bioengineer exosomes, where an antibody is covalently bonded to a fatty acid, which is then anchored into the exosomal membrane to create labeled-exosomes. Our data demonstrate that labeled-exosomes can contain up to 700,000-fold higher miRNA concentrations and can deliver miRNA cargo with increased efficiency into MDA-MB-231 TNBC cells. Results further reveal that insertion of a specific antibody-label to the exosomal membrane significantly increases microRNA uptake into MDA-MB-231 cells, and is further enhanced in cells overexpressing that same antibody marker on their surface. The customizable bioengineering of the labeled-exosomes makes it a highly versatile tool to target cells based on surface marker expression and increase miRNA or other therapeutic cargo delivery. Most importantly, the relevancy of this model reaches far beyond its success in just TNBC cells and can also be translated to several different disease models that require specific targeting with an encapsulated miRNA or therapeutic. We believe this is a novel and exciting utilization of exosomes with a high degree of customization based on surface markers on the target cell, as well as microRNA cargo loaded into the exosome to inhibit a specific oncogene.

Citation Format: Sudeepti Kuppa, Balazs Rada, Arthur Roberts, Mandi M. Murph. Nano-exosomes with miRNA: A new therapeutic approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2590.
Abstract 2598: Developing small molecule inhibitors that target androgen receptor signaling in castration-resistant prostate cancer
Authors: Chandrasekaran Balaji , Tyagi Ashish , Kolluru Venkatesh , Vadhanam Aakash M. , Baby Becca von , Gorle Suresh , Sirimulla Suman , Ramisetti Srinivasa R. , Sharma Arun K. , Ankem Murali K , damodaran Chendil
Published: August 2019

The transcription factor, androgen receptor (AR) is a key driver and plays an important role in prostate cancer. Androgen ablation therapy and brachytherapy remains the standard treatment of advanced prostate cancer, but unfortunately, it is not curative, and eventually the disease returns as lethal castration-resistant prostate cancer (CRPC). Previously we have reported that Urolithin A (Uro A), a natural compound, inhibits AR signaling and suppresses the growth of CRPC. Now, we have developed a series of pro-drug conjugates of Uro A and our initial structure-activity relationship (SAR) studies led to the identification of three small molecules as lead compounds. Hence, we investigated the effects of all three compounds and dissected their molecular mechanism in cell culture and mouse models of CRPC. All the three compounds more effectively inhibited the growth CRPC cell lines than the parent compound Uro A. Based on their IC50 concentration; we identified a novel compound (ASR-600) that demonstrated better efficacy by inhibiting AR signaling in CRPC cell lines than the parental compound Uro A. The model system and molecular dynamics (MD) stimulation studies suggest that ASR600 bind to the ligand-binding domains of AR and blocks the conformation changes, that allows AR to phosphorylate and degrade in the cytosol. Further, our thermal shift assay confirmed ASR 600 binds to AR in presence and absence of Dihydrotestostreone. Our ongoing in vivo studies, may suggest whether oral administration of ASR-600 effectively inhibits the tumor growth raised from CRPC cell lines (C4-2B, 22RV1 and enzalutamide resistance C4-2B) in xenografted mice. These observations provide a rationale for devising novel therapeutic agent based on ASR 600 for the treatment of CRPC

Citation Format: Balaji Chandrasekaran, Ashish Tyagi, Venkatesh Kolluru, Aakash M. Vadhanam, Becca von Baby, Suresh Gorle, Suman Sirimulla, Srinivasa R. Ramisetti, Arun K. Sharma, Murali K Ankem, Chendil damodaran. Developing small molecule inhibitors that target androgen receptor signaling in castration-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2598.
Abstract 260: Identifying cancer drug sensitivity using live cell imaging dynamic BH3 profiling of solid tumor core biopsies
Authors: German Rebecca , Lavrova Elizaveta , Hagan Timothy , Chipashvili Otari , Sicinska Ewa , Cleary James , Ng Kimmie , Letai Anthony , Bhola Patrick
Published: August 2019

Given the rapid development of new small molecule cancer therapeutics, there is a growing need for predictive diagnostics to match cancer patients with optimal therapies. We previously developed a precision medicine technology with a functional phenotypic readout called dynamic BH3 profiling (DBP). DBP exposes cancer cells to drugs and measures induction of apoptotic cell death signaling after 24 hours ex vivo. Nonetheless, the application of DBP to core biopsies from metastatic tumors or other limited samples remains a technical challenge. Here, we adapt the DBP protocol for use on samples with small numbers of cells such as core biopsies. We maximize information returned per cell by imaging mitochondrial integrity in response to BH3 peptide exposure over time. We first show that the adapted protocol works in limited numbers of cancer cell lines, and in limited cells from the MMTV-PyMT genetically engineered mouse model of breast cancer. Specifically, we show that our ex vivo DBP predictions of the MMTV-PyMT mouse tumor matches known in vivo response. Finally, we apply our modified protocol to patient derived xenografts of colon cancer and primary patient colon tumors. We expect that our adapted protocol will find utility as a clinical biomarker, and as a method to optimize pre-clinical drug testing.

Citation Format: Rebecca German, Elizaveta Lavrova, Timothy Hagan, Otari Chipashvili, Ewa Sicinska, James Cleary, Kimmie Ng, Anthony Letai, Patrick Bhola. Identifying cancer drug sensitivity using live cell imaging dynamic BH3 profiling of solid tumor core biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 260.
Abstract 2607: BPTF role in melanoma progression and BRAF resistance therapy
Authors: Dar Altaf A. , Majid Shahana , Semir David de , Bezrookove Vladimir , Nosrati Mehdi , Kashani-Sabet Mohammed
Published: August 2019

Bromodomain PHD finger transcription factor (BPTF) plays an important role in chromatin remodeling, but its functional role in tumor progression is incompletely understood. Here we reveal new pro-oncogenic roles for BPTF in promoting tumor cell proliferation and resistance to targeted therapies. shRNA-mediated BPTF silencing suppressed the proliferative capacity (by 65.5%) and metastatic potential (by 66.4%) of melanoma cells. Elevated BPTF mean copy number greater than 3 was observed in 28 of 77 (36.4%) melanomas. BPTF overexpression predicted poor survival in a cohort of 311 melanoma patients (distant metastasis-free survival, p=0.03, and disease-specific survival p=0.008), and promoted resistance to BRAF inhibitors in melanoma cell lines. Metastatic melanoma tumors progressing on BRAF inhibitors contained low BPTF-expressing, apoptotic tumor cell sub-clones, indicating the continued presence of drug-responsive sub-clones within tumors demonstrating overall resistance to anti-BRAF agents. These studies demonstrate multiple pro-tumorigenic functions for BPTF, and identify it as a novel target for anti-cancer therapy. They also suggest the combination of BPTF targeting with BRAF inhibitors as a novel therapeutic strategy for melanomas with mutant BRAF.

Citation Format: Altaf A. Dar, Shahana Majid, David de Semir, Vladimir Bezrookove, Mehdi Nosrati, Mohammed Kashani-Sabet. BPTF role in melanoma progression and BRAF resistance therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2607.
Abstract 2614: CCAR2 acetylation establishes a BET/BRD9 acetyl switch in response to combined deacetylase and bromodomain inhibition
Authors: Johnson Gavin S. , Rajendran Praveen , Li Li , Chen Ying-Shiuan , Dashwood W. Mohaiza , Nguyen Nhung , Ulusan Ahmet M. , Ertem Furkan , Zhang Mutian , Sun Deqiang , Huang Yun , Wang Shan , Leung Hon-Chiu E. , Lieberman David , Beaver Laura M. , Ho Emily , Bedford Mark T. , Chang Kyle , Vilar Eduardo , Dashwood Roderick H.
Published: August 2019

There continues to be interest in targeting epigenetic ‘readers, writers and erasers’ for the treatment of cancer and other pathologies. A mechanistic understanding is frequently lacking, however, for the synergy observed when combining deacetylase and bromodomain inhibitors. We identified cell cycle and apoptosis regulator 2 (CCAR2) as an early target for acetylation in colon cancer cells treated with sulforaphane (SFN). N-terminal acetylation of CCAR2 diminished its interactions with histone deacetylase 3 (HDAC3) and β-catenin, interfering with Wnt coactivator functions of CCAR2, including in cells harboring genetically encoded CCAR2 acetylation. Protein domain arrays and pull-down assays identified acetyl ‘reader’ proteins that recognized CCAR2 acetylation sites, including BRD9 and members of the bromodomain and extraterminal domain (BET) family. The BET inhibitor JQ1 synergized with SFN in colon cancer cells, and suppressed tumor development effectively in a preclinical model of colorectal cancer. Studies with SFN+JQ1 in combination implicated a BET/BRD9 acetyl switch, and a shift in the pool of acetyl ‘reader’ proteins in favor of BRD9 regulated target genes. These results highlight the competition that exists among the ‘readers’ of acetylated histone and non-histone proteins, and provide a mechanistic basis for potential new therapeutic avenues involving epigenetic combination treatments.

Citation Format: Gavin S. Johnson, Praveen Rajendran, Li Li, Ying-Shiuan Chen, W. Mohaiza Dashwood, Nhung Nguyen, Ahmet M. Ulusan, Furkan Ertem, Mutian Zhang, Deqiang Sun, Yun Huang, Shan Wang, Hon-Chiu E. Leung, David Lieberman, Laura M. Beaver, Emily Ho, Mark T. Bedford, Kyle Chang, Eduardo Vilar, Roderick H. Dashwood. CCAR2 acetylation establishes a BET/BRD9 acetyl switch in response to combined deacetylase and bromodomain inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2614.
Abstract 2619: DNA damage agents promote TFEB function and induce pro-survival autophagy signals
Authors: Marchand Benoit , Boucher Marie-Josée
Published: August 2019

The transcription factor EB (TFEB) was identified as a master regulator of autophagy and lysosomal biogenesis. We recently demonstrated that TFEB is aberrantly regulated in pancreatic cancer (PDAC) cells. Interference with TFEB impairs PDAC cell growth supporting an important role for TFEB in maintaining PDAC cell phenotype. Given the limited impact of chemotherapeutic drugs in the context of PDAC, we aimed at testing whether the aberrantly regulated TFEB in PDAC cells could confer resistance to DNA damage agents, commonly used in PDAC therapeutic regimens.

Methods: Experiments were performed in PDAC cells (MIA PaCa2, PANC1). The DNA damage agents gemcitabine, 5-FU, cisplatin and doxorubicin were used. Autophagic flux was measured upon 4-hours treatment with bafilomycin A1.

Results: Treatment with DNA damage agents 1) increased the autophagic flux in PDAC cells. This autophagic signal was associated with 2) the dephosphorylation and nuclear accumulation of TFEB. The mTORC1 pathway is well-known to regulate TFEB phosphorylation and nuclear localization of TFEB. 3) However, the impact of the DNA damage agents on TFEB appeared independent of the mTORC1 pathway since no modulation in the phosphorylation of the mTORC1 target S6K1 was observed. To delineate whether TFEB influenced the response to DNA damage agents, we generated stable populations of PDAC cells expressing a non-targeting or shRNA targeting TFEB. Interfering with TFEB function 4) prevented the autophagic response upon treatment with DNA damage agents. This correlated with 5) increased accumulation of DNA damage and 6) increased sensitivity to the DNA damage agents.

Conclusion: Our results suggest that DNA damage agents can induce a pro-survival autophagic response involving TFEB. Interfering with TFEB function limits the autophagic response and leads to increased sensitivity to DNA damage agents. Altogether, our results suggest that the aberrantly expressed TFEB in PDAC cells could confer resistance to DNA damage agents by, among others, promoting autophagy and limiting DNA damage accumulation.

Citation Format: Benoit Marchand, Marie-Josée Boucher. DNA damage agents promote TFEB function and induce pro-survival autophagy signals [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2619.
Abstract 2622: Plasma growth diefferentiation factor-15 is and independen marker for aggressive disease in endometrial cancer
Authors: Engerud Hilde
Published: August 2019

Objective: Better biomarkers are needed in order to identify patients with endometrial carcinoma at risk of recurrence and who may profit from a more aggressive treatment regimen. Our objective was to explore the applicability of plasma growth differentiation factor 15 (GDF-15) as a marker for recurrent disease, as well as a marker for poor prognosis and lymph node metastases.

Methods: EDTA-blood samples were obtained from 235 patients with endometrial cancer before primary surgery. For 36 of these patients, matching blood samples were collected at time of recurrence. Blood samples were also collected from 78 patients with endometrial hyperplasia. Plasma GDF-15 was measured by an enzyme-linked immunosorbent assay (ELISA). Preoperative pelvic MRI scans for 141 patients were investigated in parallel for imaging variables.

Results: Preoperative plasma level of GDF-15 was significantly higher for patients who experienced recurrence (1780 ng/L; 95% CI; 518-9475 ng/L) than for patients who did not develop recurrent disease (1236 ng/L; 95% CI; 307-7030 ng/L) (p<0.001). Plasma levels of GDF-15 at recurrence (2818 ng/L, 95% CI 2088-3548 ng/L) were significantly higher than plasma levels of GDF-15 measured at time of primary diagnosis (1857 ng/L, 95% CI; 1317-2398 ng/L) (p=0.001). High plasma level GDF-15 independently predicts recurrent disease (OR=3.14; 95% CI 2.10-4.76) and lymph node metastases (OR=2.64; 95% CI 1.52-4.61). Patients with high plasma level of GDF-15 had significantly larger tumor volume (p=0.008).

Conclusion: Elevated plasma level of GDF-15 is associated with aggressive disease and lymph node metastasis in endometrial carcinoma. GDF-15 may be helpful in indicating recurrent disease.

Citation Format: Hilde Engerud. Plasma growth diefferentiation factor-15 is and independen marker for aggressive disease in endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2622.
Abstract 2630: Inhibition of bone morphogenetic protein receptor 2 increases mitochondrial permeability and the downregulation of XIAP in lung cancer cells
Authors: NeMoyer Rachel E. , Langenfeld Elaine , Langenfeld John
Published: August 2019

Bone morphogenetic protein receptor (BMP) inhibitors have been shown to induce death of lung cancer cells, which involves the downregulation of x-linked inhibitor of apoptosis protein (XIAP). XIAP is a potent inhibitor of executioner caspases that promotes resistance to many chemotherapeutic agents. The mechanism by which inhibiting BMP signaling downregulates XIAP has not been elucidated. We find that the BMP inhibitors JL5 and DMH2 downregulate XIAP and enhances cell death of TRAIL, Taxol, and AEG a Smac mimetic. JL5, which inhibits both type I and type II BMP receptors, enhances cell death of cancer therapeutics by decreasing the expression of XIAP, which leads to an increase in caspase activity. The downregulation of XIAP is mediated by the inhibition of the BMP type II receptor and not the BMP type I receptors. Knockdown of BMPR2 but not the BMP type I receptors increases mitochondrial permeability resulting in the release of cytochrome c and Smac/Diablo into the cytosol. These studies suggest that the inhibition of BMPR2 increases cytosolic Smac/Diablo that inhibits XIAP enhancing apoptotic cell death of cancer therapeutics.

Citation Format: Rachel E. NeMoyer, Elaine Langenfeld, John Langenfeld. Inhibition of bone morphogenetic protein receptor 2 increases mitochondrial permeability and the downregulation of XIAP in lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2630.
Abstract 2640: DKK1 overexpression might induce crizotinib resistance
Authors: Seo Ha Young
Published: August 2019

NSCLC patients with pleural effusions tend to show progressive status and malignant features. Newly established lung cancer cell lines from pleural effusions, SNU-2550 and SNU-2563 were harboring ALK rearrangement and they were originally sensitive to crizotinib. After treated with regular crizotinib treatment and recovery at least 1 year, crizotinib-resistant cell lines (SNU-2550CR and SNU-2563CR) that became resistant to crizotinib more than 5 times were established. And then, whole exome sequencing (WES) and RNA-seq were operated in order to understand way to acquire resistance. According to WES result, there were differences in mutations between parental cell lines and resistant cell lines. For example, mutations in MKNK2, IGFN1, PRSS1 and FOXA2 genes were only present in SNU-2550CR not SNU-2550. Variations of ESX1, PRSS1, PCDHA4 and AGAP3 genes were observed in only SNU-2563CR. When the differences were studied and visualized via SPIA two-way evidence plot and heatmap, genes related with cell cycle, p53 and Wnt pathway were commonly changed in RNA expression level. In fact, there were expressional differences in genes related those pathways such as MAPK2, DKK1, APC and GSK3b genes. Among them, Dkk1 expression level was more than doubled in two set. Through those analysis, we examined differences between parental cell lines that have sensitive reactivity and resistant cell lines that acquired resistance. When crizotinib resistance was induced, Dkk1 expression was elevated. Augmentation of Dkk1 expression level induces the level of overall β-catenin expression, and cytoplasmic β-catenin tends to be concentrated adjacent to membrane and into nucleus region. Therefore, Dkk1 can be considered as a factor that is related to crizotinib resistance by up-regulating Wnt/β-catenin pathway in lung cancer. Acquired resistance to crizotinib is major predicament especially when there is ALK rearrangement. Studying the mechanism of crizotinib resistance therefore improves the prognosis of ALK rearrangement lung cancer. We found that Dkk1 overexpression might be correlated to crizotinib resistance.

Note: This abstract was not presented at the meeting.

Citation Format: Ha Young Seo. DKK1 overexpression might induce crizotinib resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2640.
Abstract 2657: GSTP mediated S-glutathionylation of GRP78 attributes to multiple myeloma resistance
Authors: Ye Zhiwei , Zhang Jie , Tew Kenneth D. , Townsend Danyelle M.
Published: August 2019

The proteasome inhibitor bortezomib (Btz) is used in the treatment of multiple myeloma (MM), but its efficacy is restricted by the wide-spread occurrence of resistance. MM cells have the highest rate of secretion of proteins with disulfide bonds and are exquisitely dependent upon redox balance and accurate protein folding. Our results showed that some important redox enzymes, including glutathione transferase P (GSTP) are upregulated in Btz-resistant cells. While GSTP was originally described as a phase II detoxification enzyme, our laboratory has ascribed a thiolase activity catalyzing the forward S-glutathionylation reaction, a post-translational modification (PTM) through reversible addition of glutathione to thiolate anions of cysteines in target proteins. Although primarily cytosolic, GSTP has been reported in the nuclear and mitochondrial compartments. We recently showed that GSTP is localized at high concentrations in the endoplasmic reticulum (ER) and regulates a number of redox active proteins through S-glutathionylation; these include glucose-regulated protein (GRP78). Proteomic analysis revealed that both cys41 and cys 420 of GRP78 were subject to S-glutathionylation and this PTM altered the activity of GRP78, enhancing its holdase activity, while concomitantly decreasing its foldase activity. This alters protein folding and contributes to the Btz-resistant phenotype of MM. Our data also support the principle that drugs that target the ER protein folding machinery significantly alter local redox conditions. Thapsigargin (Thg) is an inhibitor of SERCA, interfering with the functional activities of calcium-dependent chaperones, while tunicamycin (TuM) inhibits N-linked glycosylation. Btz resistant cells showed marked levels of cross-resistance (2-10 fold) to both. Linking such results with GSTP/redox, the absence of GSTP (from GSTP knockout mice) makes both bone marrow derived dendritic and mouse embryonic fibroblast cells more sensitive to Btz, ThG and TuM. The nature of the cross-resistance patterns and the fact that the presence of GSTP in drug naïve cells also confers resistance provides a rational platform for studying redox-based mechanisms as causative in resistance. Moreover, inhibition of GSTP with Telintra restored Btz sensitivity, decreased S-glutathionylation and increased expression of markers of UPR induced apoptosis. We conclude that altered GSTP expression and S-glutathionylation of key ER-localized proteins are significant contributors to drug response and resistance in MM treated with Btz.

Citation Format: Zhiwei Ye, Jie Zhang, Kenneth D. Tew, Danyelle M. Townsend. GSTP mediated S-glutathionylation of GRP78 attributes to multiple myeloma resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2657.
Abstract 266: Relationship between BAG3 expression and the cytotoxicity of laromustine in HL60 cells
Authors: Clarke Stanley R. , Naccara Allie H. , Loya Amanda J. , Marchant Sam W. , Wang Xiaoou , LaJoie Thomas J. , Smith Jordyn N. , Rice Kevin P.
Published: August 2019

Laromustine is an experimental sulfonylhydrazine prodrug with clinical potential against acute myelogenous leukemia and glioblastoma multiforme. Cytotoxicity is largely due to DNA crosslinking activity from an electrophilic subspecies of laromustine generated in situ. However, methylisocyanate, another electrophile cogenerated upon base-catalyzed activation of laromustine, induces acute toxicity in cultured leukemia cells. Isocyanate-mediated cytotoxicity likely involves apoptotic processes revealed in experiments presented herein showing PARP cleavage, caspase 3/7 activation, and annexin-V staining. We demonstrate that compounds that yield methylisocyanate, including laromustine, cause substantial dysregulation of gene transcription patterns that are not observed with a derivative of laromustine that possesses the DNA crosslinking activity but not the methylisocyanate. Purified mRNA from promyelocytic HL60 cells treated with either 100 µM agent or an equivalent volume of DMSO was measured using real-time RT-PCR experiments and GeneChip analyses. Among the nearly 3,000 genes dysregulated upon exposure to both laromustine and its methylisocyanate-bearing analog, BCL2-associated athanogene 3 (BAG3) emerged as a promising candidate for further investigation. This anti-apoptotic gene was significantly upregulated in these conditions. So as to assess the significance its gene product in cell death or survival in cultured cells treated with laromustine, a stable cell line expressing an shRNA construct to knock down BAG3 was engineered from HL60 cells using lentiviruses. Preliminary evidence suggests that these cells are more susceptible to the cytotoxic effects of laromustine. These data suggest that BAG3 may be part of a defensive strategy for promyelocytic leukemia cells to survive treatment with laromustine.

Citation Format: Stanley R. Clarke, Allie H. Naccara, Amanda J. Loya, Sam W. Marchant, Xiaoou Wang, Thomas J. LaJoie, Jordyn N. Smith, Kevin P. Rice. Relationship between BAG3 expression and the cytotoxicity of laromustine in HL60 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 266.
Abstract 2683: Biomarkers of glucose homeostasis and inflammation and risk of prostate cancer: A case-cohort study
Authors: Wang Ying , Campbell Peter T. , Stevens Victoria L. , Newton Christina C. , Jacobs Eric J. , Pollak Michael , Gapstur Susan M.
Published: August 2019

Background: Type 2 diabetes (T2DM) is associated with a lower risk of prostate cancer especially low-grade and localized prostate cancer. The association with aggressive prostate cancer is inconclusive. Few studies have directly examined the associations of diabetes biomarkers with prostate cancer risk. Methods: Among a cohort of 13,994 men who were on average 70.2 years (SD=5.5) and cancer free at blood draw between 1998 and 2001, 1,206 developed non-aggressive prostate cancer and 313 developed aggressive prostate cancer (AJCC stage 3-4 or Gleason score 8-10) during follow-up through June 2013. We conducted a case-cohort study including a random sub-cohort of 1,303 men, 391 non-aggressive cases and 313 aggressive cases to examine circulating hemoglobin A1c (HbA1c), c-peptide, and C-reactive protein (CRP) in relation to prostate cancer risk.

Results: HbA1c, a biomarker of hyperglycemia, was inversely associated with non-aggressive prostate cancer after adjusting for age, race, family history of prostate cancer, prostate-specific antigen screening, smoking, alcohol intake, physical activity, and total energy intake (relative risk (RR) per unit increase: 0.89, 95% confidence interval (CI): 0.79-1.00, P=0.04). Further adjustment for body mass index (BMI) attenuated the association. In contrast, HbA1c was associated with a higher risk of aggressive prostate cancer after adjusting for the covariates including BMI (RR per unit increase: 1.11, 95% CI: 0.98-1.25, P=0.11). In an analysis combining self-reported T2DM and HbA1c, men with T2DM and poor blood glucose control (HbA1c ≥6.5%) had a lower risk of developing non-aggressive prostate cancer (RR: 0.53, 95% CI: 0.30-0.95) than men without T2DM and good blood glucose control (HbA1c <6.5%). After excluding men with self-reported T2DM, HbA1c was statistically significantly positively associated with risk of aggressive prostate cancer (RR per unit increase: 1.25, 95% CI: 1.04-1.51, P=0.02) but was not associated with non-aggressive prostate cancer. C-peptide and CRP were not associated with risk of either aggressive or non-aggressive prostate cancer.Conclusions: The present study suggests that men with hyperglycemia may have a lower risk of developing non-aggressive but a higher risk of developing aggressive prostate cancer. Further studies are needed to examine the role of hyperglycemia in the etiology of aggressive prostate cancer and in prostate cancer progression.

Citation Format: Ying Wang, Peter T. Campbell, Victoria L. Stevens, Christina C. Newton, Eric J. Jacobs, Michael Pollak, Susan M. Gapstur. Biomarkers of glucose homeostasis and inflammation and risk of prostate cancer: A case-cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2683.
Abstract 2702: Contribution of effector regulatory T cells to the regulation of antitumor immunity
Authors: Dixon Michael L. , Luo Lin , Leavenworth Jianmei W.
Published: August 2019

Regulatory T cells (Treg) belonging to the FoxP3 lineage stringently control immune responses and self-tolerance. Follicular regulatory T (TFR) cells, an effector Treg (eTreg) subset, not only suppress cellular responses but also regulate the magnitude and quality of the germinal center (GC)-antibody (Ab) response through interactions with activated follicular helper T (TFH) cells and GC B cells. Although the Blimp1 transcription factor has been used as a phenotypic marker for eTreg, its contribution to the lineage stability and suppressive activity of eTreg, particularly TFR, has been clouded in uncertainty. In contrast to the current view that Blimp1 may have a negative impact on the TFR response, our recent analysis of mice that harbor a FoxP3-specific deletion of Blimp1 has shown that expression of Blimp1 in eTreg (including TFR) is essential for the maintenance of FoxP3 expression and stable eTreg suppressive phenotype. We then generated B16 melanoma model in these mice and investigated the impact of Blimp1 deficient eTreg on the tumorigenesis. These mice had delayed tumor growth compared to WT controls. The enhanced antitumor immunity in mice with Blimp1 deficient eTreg reflected reprogramming of unstable eTreg into T-cells with effector activity (Teff) specifically within the tumor and loss of suppression on TFH-Ab responses, leading to intratumoral TFH expansion, Ab deposition and enhanced CD8+ T-cell and NK cell effector function. Further analysis of mice expressing a conditional and tamoxifen-inducible Blimp1 deletion within the FoxP3+ lineage revealed the specific contribution of Blimp1 deficient TFR cells to antitumor immune response. These results suggest that induction of eTreg lineage instability provokes intratumoral eTreg conversion into Teff −a new source of effector activity by T-cells within the tumor and enhances robust Ab responses. The increased cellular and humoral responses cooperatively promote antitumor immunity. Insights from our studies may suggest new approaches to manipulate eTreg for better vaccines or combined immunotherapeutic approaches to melanoma or other types of cancer.

Citation Format: Michael L. Dixon, Lin Luo, Jianmei W. Leavenworth. Contribution of effector regulatory T cells to the regulation of antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2702.
Abstract 2717: Role of NAD+ level by NQO1 enzymatic action in regulation of hair regrowth that prevents chemotherapy-induced alopecia
Authors: Khadka Dipendra , Oh Gi-Su , Kim Hyung-Jin , Lee SeungHoon , Lee Su-bin , Sharma Subham , Kim Seon Young , Kwak Tae Hwan , Yang Sei-Hoon , Sim Hyuk , So Hong-Seob
Published: August 2019

Various types of chemotherapeutic agents are widely used to treat a variety of human neoplasms. Nonetheless, its clinical use is hampered because of severe adverse side effects such as alopecia, neutropenia, pain, cachexia, conception impairment etc. Chemotherapy-induced alopecia (CIA) is one of the fundamental unsolved problems of clinical oncology that often encountered in cancer treatment. CIA has been reported to be caused by skin inflammation through oxidative stress, DNA damage, and inflammatory responses. However, the best remedy for CIA is still not established. In a new strategy, we show that WK0202 compound as a strong NQO1 substrate that modulates the intracellular NAD+ levels by NAD(P)H quinone oxidoreductase 1 (NQO1) enzymatic action and plays important role in hair regrowth response to single (cyclophosphamide-CYP) or combined (taxol, adriamycin and cyclophosphamide-TAC) cancer therapy. Particularly, we demonstrated that cellular NAD+ levels as well as SIRT1 activity and its expression was decreased in skin with hair follicles after CYP and TAC treatment, and PARP-1 hyperactivation was associated with CIA through increased nuclear factor (NF)-κB p65 and p53 acetylation in wild type, NQO1-/- and K14-/- C57BL/6 mice. However, an increase in NAD+ levels by WK0202 completely restored SIRT1 activity and its expression, and subsequently deacetylated NF-κB p65 and p53 in wild type, however not in NQO1-/- and K14-/- mice thereby attenuating CIA. Therefore, modulation of NAD+ levels by NQO1 may be a novel therapeutic approach to prevent chemotherapy-associated hair loss, including CIA.

Citation Format: Dipendra Khadka, Gi-Su Oh, Hyung-Jin Kim, SeungHoon Lee, Su-bin Lee, Subham Sharma, Seon Young Kim, Tae Hwan Kwak, Sei-Hoon Yang, Hyuk Sim, Hong-Seob So. Role of NAD+ level by NQO1 enzymatic action in regulation of hair regrowth that prevents chemotherapy-induced alopecia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2717.
Abstract 2731: A novel PDE10/beta-catenin inhibitor, MCI-048, suppresses lung tumorigenesis to block metastasis
Authors: Zhu Bing , Ramirez-Alcantara Veronica , Ward Antonio , Berry Kristy , Keeton Adam B. , Boyd Michael R. , Maxuitenko Yulia , Chen Xi , Piazza Gary A.
Published: August 2019

We previously reported that phosphodiesterase 10A (PDE10) is overexpressed during early stages of lung cancer and is essential for lung tumor cell growth. Here we characterize a novel PDE10 inhibitor, MCI-048, that was identified by screening a library of indene compounds. MCI-048 potently inhibited the growth and induced apoptosis of multiple human lung cancer cell lines expressing PDE10, while normal human airway epithelial cells lacking PDE10 expression were appreciably less sensitive. The mechanism of action of MCI-048 involves PDE10 inhibition, cGMP elevation, PKG activation, and phosphorylation of β-catenin at key residues that induce ubiquitination and proteosomal degradation of the oncogenic pool of β-catenin in cytoplasm to suppress the translocation of active β-catenin to the nucleus and Lef/Tcf-mediated transcription of genes encoding for proteins such as c-myc, cyclin D, and survivin, which are essential for tumor cell proliferation and survival. Pharmacokinetic and tissue distribution studies revealed a unique feature of MCI-048 to accumulate at high concentrations in lungs relative to plasma and other tissues. To assess the potential of MCI-048 for the treatment of lung cancer and blocking metastasis, we tested the drug in two mouse models of lung cancer involving either orthotopic implantation of KRAS mutant A549 lung tumor cells or the chemical carcinogen, urethane. Oral administration of MCI-048 significantly inhibited tumor growth and extended survival in the orthotopic model using two different protocols to either treat the primary tumor or metastasis. Similarly, MCI-048 significantly reduced tumor burden as measured by both surface counting and histopathological analysis in the urethane-induced model of lung tumorigenesis. Biochemical analysis showed that MCI-048 reduced levels of urethane-induced active Ras-GTP and PDE10 levels, as well as other oncogenic markers, including pEGFR and c-Myc. Both mouse models revealed that MCI-048 was well tolerated with no discernable toxicity, thus supporting preclinical development for the treatment of lung cancer. Funding provided by NCI grants R21CA182941, R01CA131378, R01CA148817, R01CA197147, and R01CA155638.

Citation Format: Bing Zhu, Veronica Ramirez-Alcantara, Antonio Ward, Kristy Berry, Adam B. Keeton, Michael R. Boyd, Yulia Maxuitenko, Xi Chen, Gary A. Piazza. A novel PDE10/beta-catenin inhibitor, MCI-048, suppresses lung tumorigenesis to block metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2731.
Abstract 2735: Targeting HDAC prevents smoking-induced pancreatic cancer metastasis
Authors: Yang Jiyong , Chheda Chintan , Hauptschein Dina , Zayou Latifa , Tang Josiah , Wang Qiang , Pandol Stephen J. , Edderkaoui Mouad
Published: August 2019

Background: Cigarette smoking is an established risk factor for pancreatic ductal adenocarcinoma (PDAC). Among patients with metastatic PDAC, 90% have liver and 50% have lung metastasis. In this project we investigated the effect of smoking on pancreatic cancer invasion and metastasis in vitro and in vivo.

Methods: Pancreatic cancer cells were treated with different doses of 4-(methylnitro-s-amino)-1-(3-pyridyl)-1-butanone (NNK) and cigarette smoke extract (CSE) and cancer cell survival, markers of epithelial to mesenchymal transition (EMT) as well as invasion were measured by MTT assay, Western, RT-PCR and Matrigel Invasion Assay. In a syngeneic mouse model of pancreatic cancer mice were pre-treated with NNK for 4 weeks and mouse cancer cells were injected in the spleen of mice. Progression of the disease including metastasis to liver and lung was monitored by imaging and tissues were collected and analyzed after 6 weeks.

Results: Smoking compounds slightly but significantly increased cancer cell survival. They significantly promoted expression of EMT markers and promoted invasion of the cancer cells. Inhibition of histone deacetylase (HDAC) (class I and II), and especially HDAC4, prevented the pro-EMT and invasion effect of smoking compounds. NNK increased the protein level of HDAC4 and the level of Yes-associated protein 1 (Yap) translocated to the nucleus. Inhibition of HDAC4 reversed this effect. Analysis of Yap binding proteins showed presence of HDAC4 in the Yap protein complex. HDAC inhibition decreased the level of Yap-HDAC4 complex formation. In vivo, NNK promoted metastasis of pancreatic cancer cells to mice lung and liver; whereas, inhibition of HDAC decreased the number of metastases to a level lower than control treated mice. Smoking promoted liver and lung fibrosis and inflammation and measured by the level of collagen staining, stellate cells activation and immune cells staining. HDAC inhibition reversed these effects of smoking.

Conclusion: We showed for the first time in an animal model that smoking promotes metastasis of PDAC to the lung. We found that HDAC4 is key mediator of this effect. Inhibiting HDAC4 is a promising strategy for preventing PDAC metastasis.

Citation Format: Jiyong Yang, Chintan Chheda, Dina Hauptschein, Latifa Zayou, Josiah Tang, Qiang Wang, Stephen J. Pandol, Mouad Edderkaoui. Targeting HDAC prevents smoking-induced pancreatic cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2735.