bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5445: A novel mechanism of inhibition of ovarian cancer growth by Compound C, dorsomorphin
Authors: Ghoneum Alia , Afify Hesham M. , Said Neveen
Published: August 2018

High grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy with a five-year survival rate of 15%. As a highly aggressive cancer, HGSC has elevated energy demands to ensure its survival and proliferation in its unique peritoneal environment. Compound C or Dorsomophin is of particular interest as it is the only available cell permeable molecule that works selectively and competitively to inhibit Adenosine Monophosphate Protein-activated protein kinase or AMPK, a sensitive sensor of ATP levels. It has long been established that Compound C has a role as a BMP1 inhibitor during embryogenesis and as an inhibitor of AMPK activity in different contexts. However, the mechanism by which Compound C exerts anti-tumorigenic effects remains unknown. The purpose of this study is to understand how Compound C suppresses growth of HGSC. Our preliminary studies indicate that Compound C inhibits ovarian cancer cell proliferation and survival via a novel mechanism not only through inhibition of AMPK but also through the inhibition of upstream PI3K-Akt as well as TGFβ1/ TGFβ1/2 receptors/Smad 3,4 activation. These findings elucidate a novel mechanism of inhibition of ovarian cancer by Compound C, suggesting its potential use as a novel therapeutic agent inhibiting oncogenic and metabolic pathways.

Citation Format: Alia Ghoneum, Hesham M. Afify, Neveen Said. A novel mechanism of inhibition of ovarian cancer growth by Compound C, dorsomorphin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5445.
Abstract 5448: The role of CLCA2 in cell proliferation and survival of HNSCC—potential biomarker for sensitivity to EGFR inhibitors
Authors: Yin Yufang , Elble Randolph C.
Published: August 2018

Head and neck squamous cell carcinoma (HNSCC) develops in mucous membranes that line the mouth, throat and sinuses. Late stage disease has a poor prognosis, with 5 year survival less than 50%. The epidermal growth factor receptor (EGFR) is overexpressed in more than 90% of HNSCC, and the inhibition of EGFR is an established therapeutic strategy for HNSCC. However, sensitivity to EGFR-targeted therapy cannot be predicted from the expression level of EGFR. Only a subset of HNSCC patients benefit from anti-EGFR targeted therapy, suggesting that additional unknown pathways are involved in EGFR activation. We found that chloride channel accessory 2 (CLCA2) is frequently overexpressed in HNSCC and that its expression level predicts sensitivity to EGFR inhibitors in HNSCC cell lines. Knockdown of CLCA2 in HNSCC cancer cell line Fadu inhibited cell proliferation and sensitized cells to anoikis. Mechanistically, CLCA2 knockdown reduced EGFR signaling, which subsequently attenuated extracellular signal-regulated kinase (ERK). In addition, surface localization of cell-cell adhesion molecule E-cadherin was inhibited, corresponding to reduced cell aggregation. CLCA2 has recently been identified as a positive regulator of store operated calcium influx, and both EGFR activation and E-cadherin surface localization are known to depend on intracellular calcium release. We propose that CLCA2 overexpression in HNSCC allows the cell to better exploit EGFR proliferative signaling and protects from anoikis by promoting cell-cell aggregation. Thus, CLCA2 may serve both as a biomarker for sensitivity to EGFR inhibitors and as a target for inhibition itself.

Citation Format: Yufang Yin, Randolph C. Elble. The role of CLCA2 in cell proliferation and survival of HNSCC—potential biomarker for sensitivity to EGFR inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5448.
Abstract 5455: FDA-approved drug bazedoxifene as a novel inhibitor of IL-6 and IL-11/GP130 signaling for osteosarcoma therapy
Authors: Wu Xiaojuan , Lin Jiayuh
Published: August 2018

Objective: IL-6/IL-11/GP130/STAT3 signaling is crucial for osteosarcoma cells and tumor survival, growth and progression. Here, we show a novel IL-6/GP130 and IL-11/GP130 inhibitor, Bazedoxifene which was reported as a FDA-approved selective estrogen receptor modulator, in osteosarcoma therapy.

Methods: We treated osteosarcoma cells with different concentrations of bazedoxifene and tested expression of GP130/STAT3 signaling and the downstream genes at PCR and protein levels in different cell lines. Furthermore, cell migration and colony formation experiments were done in Bazedoxifene-treated osteosarcoma cells. To determine the in vivo activity of Bazedoxifene, we further tested the efficacy of Bazedoxifene combination treatment with temsirolimus in tumor xenografts generated from the SJSA osteosarcoma cells.

Results: Bazedoxifene appeared specific to IL-6/IL-11 as phosphorylation of STAT1 and STAT3 by IFN-γ and LIF respectively were not affected by the compound. Bazedoxifene inhibited P-STAT3, P-AKT, and induced apoptosis in human osteosarcoma cell lines expressing IL-6 and IL-11. In addition, Bazedoxifene can inhibit colony formation after the drug treatments in cancer cells. This inhibition by Bazedoxifene was partially rescued by IL-6. IFN-γ and IL-4 which do not use GP130 as a receptor and do not induce P-STAT3, did not rescue Bazedoxifene-mediated inhibition. Furthermore, IL-6 but not IFN-γ could rescue the Bazedoxifene-mediated inhibition of cell viability in osteosarcoma cells. Bazedoxifene plus temsirolimus had greater inhibition in growth of SJSA tumor xenografts than single group.

Conclusions: Bazedoxifene is novel and potent IL-6/GP130 and IL-11/GP130 inhibitor and has synergistic effect with temsirolimus treatment in osteosarcoma therapy. Repositioning a drug such as Bazedoxifene already approved for safety by the FDA as a novel inhibitor of IL-6/GP130 and IL-11/GP130 signaling should provide an easier path to clinical trials and have a potential to improve the outcome of osteosarcoma.

Citation Format: Xiaojuan Wu, Jiayuh Lin. FDA-approved drug bazedoxifene as a novel inhibitor of IL-6 and IL-11/GP130 signaling for osteosarcoma therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5455.
Abstract 5465: Resveratrol inhibits cell proliferation via crosstalk between integrin αvβ3 and IGF-1R in primary cell cultures of human uterine fibroids
Authors: Chen Yi-Ru , Shih Ya-Jung , Tang Heng-Yuan Tang , Lin Hung-Yun , Davis Paul J.
Published: August 2018

A uterine fibroid is the most common benign smooth muscle cell tumor of the myometrium. Resveratrol, a stilbene, has been used as an anti-inflammatory and antitumor agent. We aimed to determine the expression of growth factor molecules for growth inhibition after treatment of resveratrol in the primary cell lines from human uterine fibroid. In terms of growth rate, of the 24 uterine fibroid primary cell culture cells, 5 were mildly sensitive, 13 were medium-, and 6 were sensitive to resveratrol treatment. 19 out of the 24 primary cell lines responded to treatment of resveratrol from middle to sensitive ranges. Resveratrol arrested cell proliferation and also induced apoptosis, indicating that an intact apoptotic pathway was present in these cells by resveratrol. Reduction of integrin αvβ3 expression diminished resveratrol-induced antiproliferative effect in uterine fibroid cells. Resveratrol induced the expression of proapoptotic genes such as COX-2 and p21. On the other hand, the expression of proliferative (antiapoptotic) genes was either inhibited in such as BCL2 and CDKN2 or not changed in Cyclin D1 and PCNA. The expression of mRNA and protein of insulin-like growth factor-I (IGF-I) was inhibited by resveratrol in primary uterine fibroid cells. The proapoptotic proteins such as caspase 3 and caspase 9 were activated after resveratrol treatment and demonstrated that resveratrol induced apoptosis in the resveratrol-sensitive primary cell cultures, which was consistent with studies of the flow cytometry. In addition, resveratrol blocked the expression of integrin αvβ3 and protein. Concurrently, constitutive AKT phosphorylation in uterine fibroid cells was inhibited by resveratrol. Therefore, growth modulation of uterine fibroid cells occurs via mechanisms dependent on crosstalk between integrin αvβ3 and IGF-1R. Our findings suggest that resveratrol can be considered as an alternative therapeutic agent for uterine fibroid.

Citation Format: Yi-Ru Chen, Ya-Jung Shih, Heng-Yuan Tang Tang, Hung-Yun Lin, Paul J. Davis. Resveratrol inhibits cell proliferation via crosstalk between integrin αvβ3 and IGF-1R in primary cell cultures of human uterine fibroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5465.
Abstract 5474: Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin
Authors: Hart Peter C. , Chiyoda Tatsuyuki , Curtis Marion , Liu Xiaojing , Chiang Chun-Yi , McGregor Stephanie , Lastra Ricardo , Locasale Jason , Lengyel Ernst , Romero Iris L.
Published: August 2018

Sphingosine-1-phosphate (S1P), a metabolite of the phospholipid sphingosine, is a bioactive lipid that directly interacts with specific G-protein-coupled receptors to transduce signals that regulate growth, proliferation and motility. Sphingosine kinases (SPHK1 and 2) catalyze the formation of S1P from sphingosine, thereby regulating S1P homeostasis and the sphingolipid rheostat. Recently, using TCGA data, we noted SPHK1 amplification in several gynecologic cancers and that high expression of SPHK1 was associated with increased mortality in high-grade serous ovarian cancer (HGSOC). The findings reported here show that exposure of HGSOC tumor cells to exogenous S1P, or overexpression of SPHK1, induced migration, proliferation and clonogenecity in multiple ovarian cancer cell lines in vitro. Likewise, in a xenograft mouse model of ovarian cancer, overexpression of SPHK1 markedly enhanced tumor growth. In prior pre-clinical studies, we have demonstrated a strong protective effect of the diabetes medication metformin in ovarian cancer. Interestingly, we found that patients with HGSOC that use metformin for diabetes have reduced serum S1P levels compared to controls, suggesting that the sphingolipid rheostat may be a novel metabolic target of metformin in ovarian cancer. Supporting this, we identified that SPHK1 expression in ovarian cancer cell lines is reduced by treatment with metformin, and further that the reduction of SPHK1 by metformin was mediated through inhibition of transcriptional activity of hypoxia-inducible factors (HIF1α and HIF2α). Finally, we show that overexpression of SPHK1 in HGSOC cell lines enhanced the cytotoxic effects of metformin. Taken together, our data indicates that hypoxia-induced SPHK1 expression and downstream S1P signaling promote tumor progression in HGSOC, and that tumors utilizing this pathway may be particularly vulnerable to the anti-cancer effects of metformin.

Citation Format: Peter C. Hart, Tatsuyuki Chiyoda, Marion Curtis, Xiaojing Liu, Chun-Yi Chiang, Stephanie McGregor, Ricardo Lastra, Jason Locasale, Ernst Lengyel, Iris L. Romero. Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5474.
Abstract 5479: Targeting fructose-induced metabolic reprogramming in liver metastasis
Authors: Shen Xiling
Published: August 2018

Primary tumors gradually accumulate genetic alterations and are influenced by their microenvironment until they acquire the ability to metastasize to distant organs. Typical of this process, colorectal cancer (CRC) progresses through an adenoma-to-carcinoma sequence that eventually leads to metastasis, preferentially (~70% patients) to the liver. At this phase, the disease becomes challenging to treat and eventually develops resistance to most forms of combination therapy, making CRC metastasis a leading cause of cancer-related deaths. Patients with inoperable liver metastasis respond poorly to chemotherapeutic intervention and have a median survival of 6 to 9 months. Liver lesions have also been shown to seed tertiary tumors in the lungs of patients. Current chemotherapy for advanced CRC does not target liver metastases specifically. This is partly based on observations that CRC metastases are not consistently associated with any specific genetic mutations and they generally resemble cells in the primary tumor. However, emerging evidence suggests that nongenetic alterations, such as epigenetic and metabolic reprogramming, may promote cancer metastasis, including CRC. Targeting such mechanisms may provide a way to enhance therapeutics against metastasis.

In this study, pair-wise analysis of 90 matched samples (normal colon, primary CRC, liver metastasis) from 30 Stage IV CRC patients and an in vivo CRC metastasis model via cecum transplantation suggests that CRC liver metastases alter activity levels of certain metabolic pathways. LC-MS based metabolomics systematically mapped the altered metabolic pathways in CRC liver metastasis. In particular, via hypoxia-responsive GATA6 and fructose-responsive ChREBP, liver metastases upregulate ALDOB, an enzyme involved in fructose metabolism, given that 70% of fructose is metabolized in the liver. Intrahepatic implantation indicates that the liver environment causes CRC cells to upregulate ALDOB. Metabolomics and 13C-labeled fructose tracing studies indicate that ALDOB promotes fructose metabolism to fuel glycolysis, gluconeogenesis and the pentose phosphate pathway. Fructose also triggered downstream signaling to enhance lipid synthesis. ALDOB silencing or dietary fructose restriction suppresses growth of CRC liver metastases, but not primary tumors or lung metastases, highlighting the importance of tumor environment. Our findings suggest that metastatic cells can take advantage of abundant metabolites in their new microenvironment, and manipulation of involved pathways impacts the course of metastatic growth.

Citation Format: Xiling Shen. Targeting fructose-induced metabolic reprogramming in liver metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5479.
Abstract 5484: Pyruvate kinase isozymes M2 and glutaminase might be promising molecular targets for the treatment of gastric cancer
Authors: Yashiro Masakazu , Kitayama Kishu
Published: August 2018

Glycolysis is the primary mode of glucose metabolism, not only in normal cells but also in cancer cells. The Warburg effect, known as anaerobic glycolysis even in the presence of ample oxygen, might contribute to tumor development in such hypoxic environments. It has been suggested that some kinds of glucose metabolism-related enzymes—including pyruvate kinase isozyme M2 (PKM2), PKM1, enolase 1 (ENO1), and glucose-6-phosphate dehydrogenase (G6PDH)—might be associated with the anaerobic glycolysis of cancer cells. Glutamine is also associated with the proliferation of cancer cells by an alternate source of biosynthesis from the TCA cycle, namely glutaminolysis. In the present study we evaluated the significance of the enzymes for glycolysis and glutaminolysis in relation to the proliferation of gastric cancer cells in hypoxic environments. The aim of this study was to analyze the significance of glucose metabolism-related enzymes in the proliferation of gastric cancer under hypoxia. Four hypoxia-resistant gastric cancer cell lines and 4 parent cell lines were used. RT-PCR was used to evaluate the mRNA expression levels of the following metabolism-related enzymes: PKM2, GLS, ENO1, G6PDH, and PKM1. The effects of these enzymes on the proliferation of gastric cancer cells were examined using siRNAs, Shikonin as a PKM2 inhibitor, or BPTES as a GLS inhibitor, in vitro and in vivo. Levels of both PKM2 and GLS mRNA were significantly high in all hypoxia-resistant cell lines, compared with those of their parent cells. Knockdown of PKM2 and GLS significantly decreased the proliferation of all of hypoxia-resistant cells. The combination of siPKM2 and siGLS significantly decreased proliferation compared with treatment by siPKM2 or siGLS alone. The knockdown of ENO1, G6PDH, or PKM1 did not decrease the proliferation of all hypoxia-resistant cells. Combination treatment by Shikonin and BPTES inhibited the proliferation of all hypoxia-resistant cancer cells more than that by either one of the two agents. The in vivo study indicated that the tumor size treated by the combination of Shikonin and BPTES was significantly smaller than that of vehicle-treated group. These findings suggested that PKM2 and GLS might play important roles in the proliferation of hypoxic gastric cancer cells. A combination of PKM2 and GLS inhibitors might be therapeutically promising for the treatment of gastric cancer.

Citation Format: Masakazu Yashiro, Kishu Kitayama. Pyruvate kinase isozymes M2 and glutaminase might be promising molecular targets for the treatment of gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5484.
Abstract 5488: Serine racemase is a new therapeutic target for colon cancer
Authors: Ohshima Kenji , Nojima Satoshi , Wada Naoki , Hori Yumiko , Tahara Shinichiro , Kurashige Masako , Kawasaki Keisuke , Ikeda Junichiro , Morii Eiichi
Published: August 2018

Cancer cells have an altered metabolic state to meet the requirements of rapid proliferation, and altered amino acid metabolism is known to be significant for cancer cell growth. Amino acids consist of L- and D-amino acids, and humans are known to metabolize L-amino acids. D-amino acids have been considered not to exist in human body except in intestinal flora. Recently, D-serine was reported to be synthesized and catabolized by serine racemase (SRR) and D-amino acid oxidase, respectively, and it has an important function as co-activator of the N-methyl-D-aspartate receptor in the human brain. However, whether D-amino acids function in other human organs has not been elucidated. Moreover, the role of enzymes metabolizing D-amino acids in the context of cancer metabolism has not been studied. Here, we present a novel role for SRR in colon cancer. First, we analyzed SRR expression levels in colon adenoma, colon adenocarcinoma, and normal colon mucosa in ONCOMINE datasets. We found that SRR expression levels were significantly elevated in colon adenoma and colon adenocarcinoma compared to normal colon mucosa in several datasets, including that of the Cancer Genome Atlas (TCGA). To determine whether SRR has a functional role in colon cancer cells, we disrupted its expression using the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated 9 (Cas9) system in two colon cancer cell lines, HCT116 and DLD-1, using two distinct targets of short guide RNAs and examined the effects on cell proliferation. We found that SRR knockout resulted in reduced cell proliferation in both HCT116 and DLD-1 cells, which was recovered by exogenous SRR expression. In addition, a positive correlation was found between SRR expression levels and cell proliferation rate in four colon cancer cell lines, HCT116, DLD-1, WiDr, and Lovo. Moreover, phenazine methosulfate and L-aspartic acid β-hydroxamate, which have been previously reported to inhibit SRR, suppressed in vitro colon cancer cell proliferation. In conclusion, SRR is highly expressed in colon adenoma and colon adenocarcinoma compared to normal colon mucosa, and it enhances colon cancer cell proliferation. SRR is expected to be a potential new target for the development of novel therapies for colon cancer.

Citation Format: Kenji Ohshima, Satoshi Nojima, Naoki Wada, Yumiko Hori, Shinichiro Tahara, Masako Kurashige, Keisuke Kawasaki, Junichiro Ikeda, Eiichi Morii. Serine racemase is a new therapeutic target for colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5488.
Abstract 5492: Inhibition of ERK MAPK signaling increases pancreatic cancer dependency on autophagy
Authors: Bryant Kirsten , Peng Sen , Tikunov Andrey , Pierobon Mariaelena , Gunda Venugopal , Tomar Garima , Singh Pankaj , Petricoin Emanuel , Macdonald Jeffrey , Tran Nhan , Kimmelman Alec , Der Channing
Published: August 2018

Pancreatic ductal adenocarcinoma (PDAC) cell growth is dependent on altered biochemical and cellular activities that facilitate increased metabolic dependencies. We determined the role of mutationally activated KRAS, found in ~95% of PDAC, in supporting autophagy. Surprisingly, acute KRAS suppression, which blocks proliferation, was associated with increased rather than decreased autophagic flux. Similarly, KRAS transformation of immortalized human pancreatic epithelial cells showed decreased autophagic flux. Pharmacologic inhibition of ERK MAPK phenocopied the genetic silencing of KRAS and also increased autophagic flux. Addressing a mechanism for ERK suppression increased autophagy, we found increased AMPK activity, decreased mTOR activity, and increased expression of autophagic proteins. We speculated that increased autophagy may be a compensatory mechanism caused by the loss of KRAS- and ERK-dependent metabolic processes. To address this possibility, we performed RNA-seq analyses to monitor gene expression changes in response to ERK inhibition. We observed increased transcription of genes responsible for the metabolic processes of autophagy and β-oxidation, with concurrent decreased transcription of glycolysis and mitochondrial-associated genes. These changes were validated in metabolomic analyses following either genetic silencing of KRAS or ERK inhibition. Thus, the loss of ERK-driven metabolic processes may induce compensatory mechanisms to increase autophagy. We then addressed whether ERK inhibition increased PDAC dependence on autophagy. Supporting this possibility, we found that cotreatment with the autophagy inhibitor chloroquine synergistically enhanced ERK inhibitor mediated antiproliferative activity. Similarly, genetic or pharmacologic inhibition of specific regulators of autophagy also enhanced ERK inhibitor activity. We conclude that concurrent suppression of multiple metabolic processes, to block compensatory rebound activities, will be needed for effective PDAC treatment.

Citation Format: Kirsten Bryant, Sen Peng, Andrey Tikunov, Mariaelena Pierobon, Venugopal Gunda, Garima Tomar, Pankaj Singh, Emanuel Petricoin, Jeffrey Macdonald, Nhan Tran, Alec Kimmelman, Channing Der. Inhibition of ERK MAPK signaling increases pancreatic cancer dependency on autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5492.
Abstract 5494: Targeting deregulated expression and function of Mitofusin 1 in glioblastoma
Authors: Guda Maheedhara Reddy , Asuthkar Swapna , Labak Collin M. , Smith Chase P. , Tsung Andrew J. , Velpula Kiran
Published: August 2018

Glioblastoma (GBM) is the most common form of adult primary malignant brain tumor with a poor prognosis. Despite advances in standard treatments, such as surgery, radiation, and adjuvant chemotherapy, outcome remains poor. To further develop effective therapeutic approaches, it is essential to garner a better understanding of GBM progression. Substantial research has shown that GBM's progression is associated with metabolic remodeling, that includes the use of aerobic glycolysis as the main source of energy. Here, we report the novel role of Mitofusin 1 (MFN1), a key regulator of mitochondrial outer membrane fusion in glycolysis. We first established that MFN1 is highly expressed in GBM when compared to its isoform MFN2 using TCGA (The Cancer Genome Atlas) and OncomineTM glioma datasets. Silencing MFN1 using MFN1-shRNA in GBM10 cells showed decreased expression levels of PDK1 and HIF1-alpha as observed in western blotting and RT-PCR analysis. Interestingly, c-myc expression was significantly reduced in the shMFN1 treated GBM 10 cell. In addition, RNASeq analysis conducted on shPDK1 treated GBM-10 cells revealed reduced MFN1 levels. Further silencing of MFN1 showed increased OCR and decreased ECAR using seahorse XFp bio analyzer. Collectively, our preliminary data points to MFN1 as a candidate metabolic oncogene in GBM, and targeting MFN1 will be a novel GBM treatment.

Citation Format: Maheedhara Reddy Guda, Swapna Asuthkar, Collin M. Labak, Chase P. Smith, Andrew J. Tsung, Kiran Velpula. Targeting deregulated expression and function of Mitofusin 1 in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5494.
Abstract 550: One enhancer stimulates cancer cells proliferation and metastasis via the regulation of PDL1 expression
Authors: Li Chunyan , Chen Han , Liang Han
Published: August 2018

Cancer cells employ multiple mechanisms to evade the recognition by the host immune system, including the expression of the negative T cell regulatory molecule PD-L1. PD-1/PD-L1-mediated immune escape plays key role during cancer development. It is crucial to unravel the regulatory mechanism of PD-1/PD-L1. In this study, we seek one enhancer (we named “enh9”) that regulates the transcription of PD-L1 by systematic exploration. First, we found that PD-L1 and enh9 were co-expressed in multiple cancer types, including both lung adenocarcinoma and lung squamous cell carcinoma, which was further validated in a cohort of 130 lung cancer cell lines from the Cancer Cell Line Encyclopedia database. Then the direct interaction between PD-L1 and enh9 was further confirmed by Hi-C dataset. To validate the transcriptional regulation of PD-L1 by enh9, we knocked out enh9 using CRISPRi (CRISPR/ clustered regularly interspaced short palindromic repeats interference) in lung adenocarcinoma cell line A549, and single cell clones with double-copy deletion of enh9 were screened out. The expression of PD-L1 was dramatically reduced at both mRNA and protein level in enh9 knockout cells. Furthermore, we found that the cell proliferation and metastasis of enh9 knockout cells were significantly decreased compared to the control cells. Based on the previous studies that PD-L1 intrinsically regulated cancer cells' proliferation in ovarian and melanoma cancer cells, ongoing work is to determine whether enh9 regulates the cancer cell hallmarks by direct regulation of the expression of PD-L1 in lung cancer cells. The regulatory mechanisms will be deeply studied. In conclusion, we found an enhancer regulated the expression of PD-L1, which was one famous immune checkpoint, and it may play key roles in the cancer cell hallmarks.

Citation Format: Chunyan Li, Han Chen, Han Liang. One enhancer stimulates cancer cells proliferation and metastasis via the regulation of PDL1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 550.
Abstract 5503: Loss of MED12 induces tumor dormancy in human ovarian cancer
Authors: Luo Xiao-Lin , Deng Cheng-Cheng , Liu Ji-Hong , Fu Li-Wu
Published: August 2018

Epithelial ovarian cancer (EOC) is the leading cause of death among all gynecological malignancies due to high rate of disease relapse. Disease relapse in cancer patients after clinical remission are often referred to tumor dormancy. Here we identify MED12 as an important molecular regulator of tumor dormancy. We found that MED12 knock-out could induce dormancy of EOC cells in vitro and in vivo. Mechanistically, microarray analysis showed that MED12 knock-out decreased the expression of EGFR. Restoration of EGFR expression in MED12 knock-out cells restored the proliferation ability. Additionally, we found that MED12 could bind to the promoter of EGFR, and correlation studies showed that MED12 expression positively correlated with the level of EGFR. Clinical data demonstrated that chemotherapy-resistant patients showed a lower expression of MED12. In conclusion, MED12 plays an important role in regulating dormancy of EOC through regulation of EGFR.

Citation Format: Xiao-Lin Luo, Cheng-Cheng Deng, Ji-Hong Liu, Li-Wu Fu. Loss of MED12 induces tumor dormancy in human ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5503.
Abstract 5508: ANKRD52 inhibited tumor metastasis in lung adenocarcinoma
Authors: Lee Ting-Fang , Lin Yen-Fan , Liu Ying-Pu , Wu Cheng-Wen
Published: August 2018

Cancer metastasis is an ultimate challenge in our effort to fight cancer as a life-threatening disease. A member of ankyrin repeat proteins, ankyrin repeat domain 52 (ANKRD52), is studied here to be involved in the regulation of lung adenocarcinoma metastasis. Ankyrin repeat proteins are known to function as a platform for protein-protein interactions, and ANKRD52 was shown to interact with protein phosphatase 6 (PP6). Immunohistochemistry staining in lung adenocarcinomas tissues revealed low ANKRD52 expressing in stage-IV patients compared to those in stages I to III. Overexpressed ANKRD52 prevented lung cancer formation in the xenograft model. Using lung cancer cell lines, ANKRD52 knockdowns showed significantly increased cell mobility while forced expression decreased cell mobility. Using mass spectrometry analysis, p21-activated kinases (PAK1) was identified to interact with ANKRD52. The regulation of PAK1 phosphorylation by the ANKRD52-PP6 complex is essential to cell mobility. Our model demonstrated a novel anti-metastatic protein, ANKRD52, that regulates cell mobility through interacting with PP6 leading to PAK1 dephosphorylation.

Citation Format: Ting-Fang Lee, Yen-Fan Lin, Ying-Pu Liu, Cheng-Wen Wu. ANKRD52 inhibited tumor metastasis in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5508.
Abstract 551: Discovering the co-drivers of mutant TP53 that promote breast cancer progression
Authors: Pal Anasuya , Park Jin , LaBaer Joshua
Published: August 2018

Breast cancer is a heterogeneous disease and has different subtypes. Genetically 30% of all breast tumors and 80% of basal-like breast tumors harbor mutations in TP53 and numerous somatic mutations in other genes. This molecular heterogeneity has posed a challenge in developing effective therapeutic regimens and targeted therapies. Different TP53 missense mutations co-exist with other mutations in tumors and we hypothesize that tumor heterogeneity results from combinatorial effects of neo-morphic functions of specific TP53 driver mutations and a distinct subset of functionally important co-mutations (or ‘co-drivers'). We ectopically expressed the ten most prevalent missense TP53 mutants found in breast cancer tumors in non-transformed mammary epithelial cells and examined their phenotypes associated with the hallmarks of cancer. The results showed wide spectrum of phenotypic changes in cell survival, resistance to apoptosis and anoikis, cell invasion and cell polarity. As a proof of concept for the ‘co-driver', we knocked-out PTEN in a non-invasive TP53 Y234C mutant using the CRISPR system and observed increased cell invasion. A subsequent genome-wide CRISPR library-based screen on non-invasive TP53 Y234C expressing cells identified co-driver candidates that were highly enriched in the invasive population of Y234C cells. The top candidates included several known mutated genes in breast cancer patients with TP53 mutations, and were associated with signaling and cytoskeletal pathways that play crucial role in regulating cell invasion. These results demonstrate that this approach can pinpoint the key loss-of-function mutations in clinically important TP53 mutant backgrounds that can promote cancer-like behavior, and identify the combinations of ‘TP53 mutant and co-driver pathways' that can be targeted by specific inhibitors.

Citation Format: Anasuya Pal, Jin Park, Joshua LaBaer. Discovering the co-drivers of mutant TP53 that promote breast cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 551.
Abstract 5510: Loss of epithelial membrane protein 2 enhances Kras-driven lung tumorigenesis via FAK/AKT pathways
Authors: Jang Ji Yun , Park Mi Kyung , Lee Chang Hoon , Lee Ho
Published: August 2018

Epithelial membrane protein-2 (EMP2) belongs to the growth arrest specific-3 (GAS3)/PMP22 family of tetraspan proteins. These family members are involved in the pathogenesis of human diseases, including malignancy. EMP2 is highly expressed in normal lung alveoli; however, its functional role in lung tumor is largely unknown. In this study, we focus a novel function for EMP2 in lung tumor progression. To investigate this possibility, EMP2 knock-out mice were crossed with KrasG12Dmice that carry an oncogenic mutation of the Kras gene (G12D) and develop lung adenocarcinoma. Incidence of lung tumor in KrasG12DEMP2-/- mice was higher than that in KrasG12DEMP2+/+ mice. We also found that loss of EMP2 accelerated lung tumor progression. Then, we investigated the role of EMP2 in lung cancer cell line. Expression of EMP2 was knocked out by CRISPR/Cas9 editing system in H1299 (KrasWT), H358 (KrasMut) and A549 cells (KrasMut). Loss of EMP2 induced that expression of integrin α5 is increased but expression of integrin α6 is decreased. Alteration of integrin expression activated FAK/AKT pathway. These results support the role of EMP2 loss in the control of lung cancer progression with oncogenic Kras. Taken together, these findings establish that EMP2 is a potent suppressor of Kras-driven lung tumorigenesis via FAK/AKT pathway.

Citation Format: Ji Yun Jang, Mi Kyung Park, Chang Hoon Lee, Ho Lee. Loss of epithelial membrane protein 2 enhances Kras-driven lung tumorigenesis via FAK/AKT pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5510.
Abstract 5515: Ras-like estrogen-regulated growth-inhibitory gene (RERG): A novel biomarker and potential therapeutic target for women with lung cancer
Authors: Scoyk Michelle Van , Avasarala Sreedevi , Wu Pei-Ying , Su Yanlin , Lerner Lane , Hulbert Alicia , Bikkavilli Kamesh , Winn Robert A.
Published: August 2018

Background: Lung cancer is the second most common cancer diagnosed in women. In fact, twice as many women will die from lung cancer compared to breast cancer, the key risk factor being tobacco use. Hence, there is a need to identify new molecular biomarkers to aid in early detection and develop new therapeutic strategies in tobacco-related lung cancer. Ras-like Estrogen-Regulated Growth-Inhibitory Gene (RERG) is a member of the Ras superfamily of GTPases that play an important role in cellular processes such as proliferation, differentiation, and apoptosis. Unlike other members of the Ras superfamily members of proto-oncogenes, RERG functions as a tumor suppressor.

Objective: To investigate the utility of RERG expression as a novel biomarker and a potential therapeutic target in lung cancer.

Results: In silico analysis of The Cancer Genome Atlas (TCGA) lung cancer datasets revealed a significant downregulation of RERG expression in lung tumors. Furthermore, reduced expression of RERG in lung tumors was also observed to be correlated with poor prognosis as determined by Kaplan-Meier survival analysis. Evaluation of formalin-fixed, paraffin-embedded (FFPE) human lung cancer tissues and fresh frozen lung tumor tissues corroborated our in silico observations. Most notably, tobacco smoke was identified to be associated with decreased RERG expression in lung tumors. The most intriguing observation from this study is the significant decrease of RERG expression in female smokers as a result of promoter hypermethylation.

Conclusion: Taken together, these findings suggest that RERG may represent a potential biomarker in lung cancer, particularly among smokers. Further investigation would focus on the mechanism of RERG loss and its influence on lung tumor development, particularly in female smokers.

Citation Format: Michelle Van Scoyk, Sreedevi Avasarala, Pei-Ying Wu, Yanlin Su, Lane Lerner, Alicia Hulbert, Kamesh Bikkavilli, Robert A. Winn. Ras-like estrogen-regulated growth-inhibitory gene (RERG): A novel biomarker and potential therapeutic target for women with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5515.
Abstract 5519: BAP1 modulates gene-environment interaction in carcinogenesis
Authors: Carbone Michele , Bononi Angela , Giorgi Carlotta , Patergnani Simone , Pass Harvey I. , Jia Wei , Pinton Paolo , Yang Haining
Published: August 2018

We discovered that heterozygous germline BAP1 mutations (BAP1+/-) cause a novel cancer syndrome that we named “The BAP1 cancer syndrome” characterized by development of malignant mesothelioma (MM), uveal and cutaneous melanoma, and other cancers. We demonstrated how germline BAP1 mutations are transmitted over the centuries across generations and found that 100% of individuals who inherited germline BAP1 mutations have developed one or more malignancies in their lifetime. Very recently we demonstrated that the potent BAP1 tumor-suppressor activity is linked to its dual function in the nucleus, where it regulates DNA repair, and in the cytoplasm, where it regulates apoptosis by deubiquitylating and stabilizing the IP3R3 endoplasmic reticulum (ER) Ca2+ channel. In parallel we discovered that cells carrying heterozygous BAP1 mutations derive energy largely via aerobic glycolysis, Warburg effect. Now we have found the mechanisms regulated by BAP1 that are responsible for the changes in metabolism. We discovered that reduced BAP1 levels lead to reduced release of Ca2+ from the ER into the cytoplasm and reduced intra-mitochondrial Ca2+ levels. Reduced mitochondrial Ca2+ levels directly impair aerobic respiration and cells switch to glycolysis even in the presence of oxygen. We demonstrate that aerobic glycolysis can be induced in apparently any human cell type by reducing BAP1 levels using siRNAs or other strategies, and that in these cells glycolysis can be reverted to aerobic respiration upon re-establishing normal Ca2+ levels. In conclusion, our findings indicate how BAP1 deficiency regulates DNA repair and apoptosis and how low BAP1 levels induce the Warburg effect, an effect seen in all “normal” cell types from individuals born with inherited germline heterozygous BAP1 mutations. In these individuals aerobic glycolysis predates by many years malignant transformation.

Citation Format: Michele Carbone, Angela Bononi, Carlotta Giorgi, Simone Patergnani, Harvey I. Pass, Wei Jia, Paolo Pinton, Haining Yang. BAP1 modulates gene-environment interaction in carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5519.
Abstract 5520: Oncogenic RTK signaling inhibits Spred1/NF1 to sustain constitutive Ras/MAPK signaling
Authors: Markegard Evan , Mercado Ellen L. , Castel Pau , Silva Jillian , Galeas Jacqueline , Li Kathy , Urisman Anatoly , McCormick Frank
Published: August 2018

Spred proteins negatively regulate Ras/MAPK signaling following growth factor stimulation. Inhibition of Ras primary occurs through Spreds ability to bind and localize NF1, a RasGAP and major tumor suppressor, to the plasma membrane. Spred1 and NF1 loss-of-function mutations occur across multiple cancer types including non-small cell lung carcinoma, glioblastoma, melanoma, stomach carcinoma, and uterine carcinosarcoma. Here we demonstrate that oncogenic RTK signaling leads to phosphorylation of Spred1(S105) in the EVH domain, which disrupts Spred1-NF1 binding and function. Phosphomimetic Spred1 is unable to suppress Ras-GTP following growth factor stimulation and cancer cell proliferation. The Spred1(S105) kinase is likely to be a CDK based on in vitro kinase and in vivo cell line assays. Our findings provide one potential mechanism by which oncogenic RTK signaling disrupts negative feedback to sustain constitutive Ras signaling. Furthermore, this work may elucidate a novel therapeutic target for restoring NF1-mediated inhibition of Ras.

Citation Format: Evan Markegard, Ellen L. Mercado, Pau Castel, Jillian Silva, Jacqueline Galeas, Kathy Li, Anatoly Urisman, Frank McCormick. Oncogenic RTK signaling inhibits Spred1/NF1 to sustain constitutive Ras/MAPK signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5520.
Abstract 5537: Circulating tumor DNA analysis for ESR1 mutations in patients with hormone receptor-positive metastatic breast cancer
Authors: Sim Sung Hoon , Jeon Su Yeon , An Kyoung Hee , Kong Sun Young , Kwon Min Jung , Lee Keun Seok , Park In Hae
Published: August 2018

Background: ESR1 mutations are known as a major mechanism of resistance to antihormonal therapy in breast cancer. ESR1 mutation frequency is high in metastatic disease when the tumor is refractory to aromatase inhibitor, in contrast to nonmetastatic setting. We tried to detect ESR1 mutations (Y537N, Y537S and D538G) in circulating tumor DNA (ctDNA).

Method: Patients who had hormone receptor-positive breast cancer were enrolled in this study. Plasma samples were collected and ctDNA was analyzed by ddPCR and digital targeted DNA panel. Primers and probes for ddPCR were designed for Y537N, Y537S and D538G mutations using sequences of wild-type normal human DNA.

Results: A total of 40 patients were enrolled. Histologic type was invasive ductal carcinoma (IDC) in 32, invasive lobular carcinoma (ILC) in 4 and others in 4. Thirty-four patients received endocrine treatment and 6 patients had no prior exposure to endocrine treatment. Using ddPCR, overall mutation rate was 52.5% (n=21). D538G was the most frequent mutation (n=16), followed by Y537N (n=9), and Y537S (n=6). Nine patients showed multiple ESR1 mutations. In patients without endocrine exposure (n=6), 2 patients showed ESR1 mutations (Y537N, Y537S). The mutation detection rate was higher in patients with prior use of aromatase inhibitor (AI) than in prior use of tamoxifen (TMX) only (prior AI, 17/29=58.6%; prior TMX, 2/5= 40%). In 9 cases, we conducted both ddPCR and targeted DNA panel assay using ctDNA at the same time. Overall concordance rate between two platforms was 55.6% (5/9). Among discordant cases (n=4), ESR1 mutations were detected by ddPCR in 3 cases, which were not found in DNA panel assay.

Conclusions: ESR1 mutations can be robustly identified with ctDNA analysis. Overall mutation detection rate was comparable to other previous reports. However, there is a significant discordance between clinically available NGS panel assay and ddPCR method in detection of ESR1 mutations. Further study will be needed for clinical implementation of ESR1 mutation analysis using ctDNA.

Citation Format: Sung Hoon Sim, Su Yeon Jeon, Kyoung Hee An, Sun Young Kong, Min Jung Kwon, Keun Seok Lee, In Hae Park. Circulating tumor DNA analysis for ESR1 mutations in patients with hormone receptor-positive metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5537.
Abstract 554: APC loss alters DNA damage repair in breast cancer cells
Authors: Batista Stephanie M. McClintock
Published: August 2018

Breast cancer is the second leading cause of cancer deaths in U.S. women. Many of these deaths have been attributed to the development of chemotherapeutic resistance. Thus, understanding the process of chemotherapeutic resistance will help develop new approaches to combat breast cancer and ultimately cause a decrease in breast cancer related deaths. The Adenomatous Polyposis Coli (APC) tumor suppressor is silenced or mutated in up to 70% of sporadic breast cancer; however, the possible effects of APC loss on chemoresistance has not been elucidated. Using the ApcMin/+ mouse crossed to the Polyoma middle T antigen (PyMT) transgenic model, we previously showed that APC loss decreased cisplatin and doxorubicin-induced apoptosis. We also have shown that APC loss increased mRNA expression of the multidrug resistance protein 1 (MDR1), which was augmented by doxorubicin treatment. Treatment with doxorubicin and A69, a STAT3 inhibitor, normalized MDR1 gene expression in MMTV-PyMT;ApcMin/+ cells. Here, we hypothesize that loss of APC causes an increase in doxorubicin efflux and a decrease in DNA damage. First, we show that APC loss increased MDR1 activity as measured by calcein flux. To determine whether MDR1 inhibition would restore doxorubicin induced DNA damage, a combination treatment of doxorubicin and the MDR1 inhibitor, Valspodar, was able to restore doxorubicin sensitivity in MMTV-PyMT;ApcMin/+ cells compared to the control MMTV-PyMT;Apc+/+ cells. In addition, we have shown a decrease of γH2AX, a marker of damaged DNA, in MMTV-PyMT;ApcMin/+ cells treated with doxorubicin suggesting that the MMTV-PyMT;ApcMin/+ cells either have less damage due to increased drug efflux via MDR1 or due to increased DNA damage repair. Due to APC binding to Topoisomerase IIa, we also examined the degree of Topoisomerase IIa inhibition (via doxorubicin and etoposide) in MMTV-PyMT;ApcMin/+ compared to MMTV-PyMT;Apc+/+ cells. Topoisomerase IIa activity will also be measured to determine the effect of APC loss on Topoisomerase IIa. To test the hypothesis that loss of APC affected DNA damage repair, the expression of phosphorylated H2AX was measured in MMTV-PyMT;ApcMin/+ and MMTV-PyMT;Apc+/+ cells treated with the following: doxorubicin, etoposide, Valspodar, or a combination treatment. The longevity of doxorubicin-induced double stranded breaks was observed. Future studies will measure DNA damage repair pathway efficiency via reporter plasmids. We also will measure downstream signaling of yH2AX. Overall with an understanding of the role of APC in DNA damage repair, the use of a combination therapy could be advantageous to overcome chemotherapeutic resistance.

Citation Format: Stephanie M. McClintock Batista. APC loss alters DNA damage repair in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 554.