bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2769: A squalene epoxidase-cholesterolaxis drives colorectal cancer progression and metastatic dissemination
Authors: Jun Soo Young , Brown Andrew J. , Yoon Ji-Yong , Lee Jeong-Ju , Chua Ngee Kiat , Yang Jin OK , Min Ju-Sik , Jang Insu , Jeon Su-Jin , Choi Min-Hyuk , Choi Tae-Ik , Kim Cheol-Hee , Kim Nam-Soon
Published: August 2019

Links between cholesterol and cancer are well-documented, but the mechanisms remain unclear. Squalene epoxidase (SQLE), a key enzyme in cholesterol biosynthesis degraded by excess cholesterol, is suggested as a proto-oncogene. Paradoxically, we found reduced SQLE in aggressive colorectal cancer (CRC); low SQLE being associated with a shortened survival of CRC patients. This was confirmed in a spontaneous CRC metastasis mouse model where SL-15 reduction, by either a high-cholesterol regimen or genetic knockdown, strikingly promotes CRC aggressiveness through the production of migratory cancer stem cells. Experiments in CRC cell-lines demonstrated that SQLE reduction helps overcome constraints for malignant transformation. Specifically, we uncovered a surprising interaction of SQLE with GSK3β and p53. Depletion of SQLE disrupted the GSK3β/p53 complex, resulting in a metastatic phenotype. Our findings provide mechanistic insights into the link between cholesterol and CRC, identifying SQLE as a key regulator in CRC progression and potentially a biomarker for risk assessment.

Citation Format: Soo Young Jun, Andrew J. Brown, Ji-Yong Yoon, Jeong-Ju Lee, Ngee Kiat Chua, Jin OK Yang, Ju-Sik Min, Insu Jang, Su-Jin Jeon, Min-Hyuk Choi, Tae-Ik Choi, Cheol-Hee Kim, Nam-Soon Kim. A squalene epoxidase-cholesterolaxis drives colorectal cancer progression and metastatic dissemination [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 2769.
Abstract 2776: Mitochondrial calcium uniporter in pancreatic cancer metastasis and metabolic stress resistance
Authors: Wang Xiuchao , Lin Shengchen , Sun Jianwei , Kang Jiaxin , Hao Jihui , Yang Shengyu
Published: August 2019

Despite recent advances in cancer diagnosis and therapeutic modalities, the prognosis for pancreatic ductal carcinoma (PDAC) remains very poor. Most PDAC patients succumb to local and distant metastasis soon after the initial diagnosis. Therefore understanding molecular mechanisms underlying PDAC metastasis is crucial to the development of more effective PDAC therapies. Here we examined the role of mitochondrial calcium uniporter (MCU), a mitochondrial inner membrane calcium channel responsible for mitochondrial Ca2+ uptake, in pancreatic cancer metastasis and progression. We discovered that MCU is overexpressed in PDAC when compared to adjacent pancreatic tissues. MCU overexpression in PDAC patients is significantly associated with PDAC lymph node metastasis, histologic grade and pTNM stage. We also found that higher levels of MCU in PDAC patients was associated with worse overall survival (OS, P<0.01) and relapse-free survival (RFS, P<0.05) after surgical resection of tumors. MCU knockdown inhibits the PDAC cell motility, invasiveness, metabolic stress resistance and chemoresistance in cell culture models and PDAC metastasis in an orthotopic xenograft mouse model. Mechanistically, MCU controls the activation of the Keap1-Nrf2 signaling pathway through promoting mitochondrial ROS production and the oxidation of mitochondrion-recruited Keap1. Our data support that MCU regulates cancer cell metabolic stress resistance and oxidative stress response to drive PDAC metastasis and progression. Inhibiting MCU expression or blocking mitochondrial calcium influx may be an attractive approach for treating metastatic PDAC.

Citation Format: Xiuchao Wang, Shengchen Lin, Jianwei Sun, Jiaxin Kang, Jihui Hao, Shengyu Yang. Mitochondrial calcium uniporter in pancreatic cancer metastasis and metabolic stress 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 2776.
Abstract 2802: In situ detection of PD-1+CXCL13+CD8+ T cells in non-small cell lung cancer
Authors: Li Na , Zhang Bingqing , Jhaveri Niyati , Zhang Zhifu , Wang Xin , Sun Hongzhe , Zhou Ying , Anderson Courtney , Ma Xiao-Jun
Published: August 2019

Recent reports identified one subset of intratumoral CD8+ cytotoxic T lymphocytes (CTLs) in non-small cell lung cancer (NSCLC) that are PD-1high with distinct molecular and functional properties. Strikingly, these cells produce very high levels of CXCL13 mRNA and protein, which may mediate immune recruitment. Furthermore, the presence of PD-1high CD8+ T lymphocytes are strongly predictive for both response and survival in NSCLC patients treated with PD-1 blockade. Thus, it is of great value to develop a practical biomarker assay to specifically detect these cells in formalin-fixed paraffin-embedded (FFPE) tumor biopsies. In this study, we combined the highly sensitive and specific RNAscope multiplex fluorescent RNA in situ hybridization (ISH) assay detecting CXCL13 and PDCD1 mRNAs with immunohistochemistry (IHC) detecting CD8 protein in a single tissue section to directly visualize PD-1+CXCL13+CD8+ T lymphocytes in NSCLC tissues. Two NSCLC tissue microarrays (TMAs) consisting of 63 independent patient FFPE samples were stained with full automation using the Leica BOND RX instrument. The resulting slides were scanned, and the images were analyzed using the Perkin Elmer Phenochart software. 57 of the 63 TMA cores were available for image analysis. Each tissue core was first examined under 4X magnification, then snapshot images of three independent 40X fields with enriched CD8+ cells (if present) were taken. CD8+ cells, CXCL13+ cells, and PD-1+ cells in each snapshot were counted. Every snapshot contained both stromal and tumor regions. 43 samples contained high (>20) CD8+ CTLs whereas 14 samples contained low (≤20) CD8+ CTLs across the three snapshots. Interestingly, PD-1+CXCL13+CD8+ cells were detected in both high and low CTL tumors. Five of 57 tumors carried high percentages of PD-1+CXCL13+CD8+ cells (>10% of CD8+ CTLs), with three from high CTL tumors and two from low CTL tumors. These results demonstrate that this fully automated multiplexed RNAscope dual ISH/IHC assay allows for co-localization of RNA and protein biomarkers in single cells with morphological context. The ability to detect RNA and protein in a single slide-based assay enables immune profiling applications to include biomarkers such as secreted proteins and non-coding RNAs that are difficult or impossible to detect by IHC.

Citation Format: Na Li, Bingqing Zhang, Niyati Jhaveri, Zhifu Zhang, Xin Wang, Hongzhe Sun, Ying Zhou, Courtney Anderson, Xiao-Jun Ma. In situ detection of PD-1+CXCL13+CD8+ T cells in non-small cell lung 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 2802.
Abstract 2804: Metabolic-immunoregulatory role of CCRK-mTOR signaling in NAFLD-associated hepatocellular carcinoma
Authors: TANG Wenshu , ZHOU Jingying , YANG Weiqin , FENG Yu , MOK Myth , CHENG Alfred Sze
Published: August 2019

Obesity increases the risks of steatosis, non-alcoholic steatohepatitis (NASH) and HCC development. Non-alcoholic fatty liver disease (NAFLD) associated-hepatocellular carcinoma (HCC) is a male-predominant cancer mainly caused by metabolic disorder. Our previous findings demonstrated that cell cycle-related kinase (CCRK), through upregulates mTORC1 pathway, resulting in deregulated lipid/glucose metabolism and tumorigenesis (Nat Communs accepted). In this study, we further elucidate that CCRK activates mTORC1 through SLC3A2 and SLC7A5 dependent amino acid transportation. We performed comprehensive immune cell profiling in a high-fat high-carbohydrate diet (HFHC)-induced obesity and NASH murine model and uncovered activation of CCRK-mTORC1 signaling cascade and specific induction of myeloid-derived suppressor cell (MDSC), reduction in CD8+ T cells, which subsequently enhanced tumor growth of orthotopically-implanted HCC tumor cells. Notably, treatment of the mTORC1/C2 dual kinase inhibitor vistusertib (AZD2014), currently undergone phase I/II clinical trials, abrogated mTORC1/SREBP2 signaling and metabolic dysregulation especially cholesterol levels. Further immune profiling in liver and blood of AZD2014 treated mice will be performed. Furthermore, mTORC1/SREBP2 positively associated with cholesterol level in the streptozotocin (STZ)-HFHC induced spontaneous NAFLD-HCC mouse model, which will be utilized to further study the therapeutic effect of vistusertib in vivo. Collectively, this study will elucidate the metabolic-immunosuppressive role of CCRK-mTOR signaling in NAFLD-associated HCC and further provide insights into development of therapeutic strategies against the CCRK-mTOR reinforced NAFLD-HCC. This project is supported by Collaborative Research Fund C4017-14G and the Focused Innovations Scheme 1907309.

Citation Format: Wenshu TANG, Jingying ZHOU, Weiqin YANG, Yu FENG, Myth MOK, Alfred Sze CHENG. Metabolic-immunoregulatory role of CCRK-mTOR signaling in NAFLD-associated 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 2804.
Abstract 2805: DFMO and 5-azacytidine increase M1 macrophages in the tumor microenvironment of an ovarian cancer mouse model
Authors: Travers Meghan , Brown Stephen , Dunworth Matthew , Holbert Cassandra , Casero Robert , Zahnow Cynthia
Published: August 2019

Although ovarian cancer has a low incidence rate encompassing roughly 1% of all new cancers, it remains the most deadly gynecologic malignancy. Our lab has designed a novel combination therapy which combines a DNA methyl transferase inhibitor (DNMTi) and ornithine decarboxylase inhibitor that together, alter the tumor microenvironment to inhibit ovarian tumor growth. Previous work has demonstrated that the DNMTi 5-Azacytidine (AZA) activates type I interferon signaling (Li, 2014, Chiappinelli, 2015) to increase IFNγ+ T cells and NK cells and reduce the percentage of macrophages and myeloid derived suppressor cells (MDSCs) in the tumor microenvironment (Stone, 2017). To improve the efficacy of epigenetic therapy, we hypothesized that the addition of α-difluoromethylornithine (DFMO), an ornithine decarboxylase inhibitor may decrease activity of MDSCs through inhibition of arginase. Immunocompetent C57Bl/6 mice were injected with syngeneic mouse ovarian surface epithelial (MOSE) tumor cells (ID8-VEGF-Defensin) and subsequently treated with AZA, DFMO, or combination AZA+DFMO. After several weeks, mice developed hemorrhagic ascites that was drained, processed and stained for cell-surface markers and analyzed by flow cytometry to identify T cells, NK cells, and macrophages. We found that in vivo AZA, DFMO, and AZA+DFMO significantly increased survival in mice, decreased tumor burden, and caused recruitment of activated (IFNγ+) CD4+ T cells, CD8+ T cells, and NK Cells compared to vehicle. The combination therapy had a striking increase in survival when compared to single agent treatment; however, the difference in recruited lymphocytes was less striking. Instead, combination therapy led to the most dramatic decrease in immunosuppressive cells such as M2 polarized macrophages and increase in tumor-killing M1 macrophages. Using a CSF1R blocking antibody, we found that depleting macrophages in this model reduced the efficacy of AZA+DFMO treatment, and resulted in fewer M1 macrophages in the tumor microenvironment. We thus conclude that our novel combination therapy modifies macrophage polarization in the tumor microenvironment, recruiting M1 macrophages and prolonging survival. We hypothesize that this treatment regimen could have a widespread impact on macrophage-rich tumors in general, and plan to test this hypothesis in additional tumor models.

Citation Format: Meghan Travers, Stephen Brown, Matthew Dunworth, Cassandra Holbert, Robert Casero, Cynthia Zahnow. DFMO and 5-azacytidine increase M1 macrophages in the tumor microenvironment of an ovarian cancer mouse model [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 2805.
Abstract 2816: SB1703 has therapeutic effect on syngeneic mouse model as an immune modulator in TME
Authors: Kim Hyo Young , Kim Hee-Jung , Jung Jae Hoon , Jo So Young , Kim Ju Hee , Cho Wansang , Kim Mingi , Yim Junhyeong , Park Seung Bum
Published: August 2019

Although stage I melanoma is highly curable, the prognosis of late stage melanoma is poor and treatment options are limited to immune checkpoint modulators (ICMs). In this study, we synthesized a novel small molecule, SB1703, and identified high-mobility group box (HMGB) proteins as the direct binding target proteins. SB1703 inhibited melanoma growth in B16F10 syngeneic mouse model. To elucidate the tumor growth inhibitory mechanism, we determined the changes in myeloid-derived suppressor cell (MDSC) number during drug treatment. MDSCs expand in disease states such as cancer and have immune suppressive functions. Serum HMGB1 and interleukin (IL)-6 levels were increased in vehicle administered mice and decreased in SB1703 administered mice. We examined the possibility of combinatorial treatment with SB1703 and ICMs. SB1703 showed synergistic effect with ICMs. In conclusion, SB1703 exhibited therapeutic effects against melanoma in both single and combination treatments with ICMs, which might be due to modulation of myeloid cells such as MDSCs

Citation Format: Hyo Young Kim, Hee-Jung Kim, Jae Hoon Jung, So Young Jo, Ju Hee Kim, Wansang Cho, Mingi Kim, Junhyeong Yim, Seung Bum Park. SB1703 has therapeutic effect on syngeneic mouse model as an immune modulator in TME [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 2816.
Abstract 2827: Identification of chemotherapeutic resistant microbiota profile in colorectal cancer
Authors: Rao Shuyun , King Charles Hadley , Mazumder Raja , Gu Shoujun , Amdur Richard , Mishra Bibhuti , Mishra Lopa
Published: August 2019

Background: Emerging data shows a rise in CRC incidence in men and women under 55 years of age, with a potential new risk factors including alterations in the microbiome. While recent advances have significantly reduced CRC morbidity and mortality, such as screening and new therapeutic strategies, how the microbiome modulates CRC chemotherapy response remains understudied. This alarming trend presents an urgent need for further understanding of the molecular mechanisms and “signatures” of the gut microbiome in CRC patients. Key driving pathways in CRC include WNT, RAS, RAF, APC and TGF-β signaling. Modulating the gut immune response includes multiple mechanisms, including sensors through carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) that serve as receptors to microbes, and crosstalk with signaling pathways such as TGF-β signaling pathway. Interestingly, disruption of TGF-β leads to increased sensitivity to cisplatin and other DNA cross-linking agents.

Hypothesis and Aims: Our hypothesis is that the gut microbiome plays a key role in modulating the TGF-β pathway by CEACAMs binding to specific microbial species, thereby impeding the TGF-β pathway and altering chemotherapy response. Our aims are to explore TCGA genomics, and functional interactions between gut microbiota, CEACAMs, and TGF-β signaling in processing chemotherapy response.

Methods and Results: We first analyzed microbiome signatures in normal and CRC patients, and identified a signature pattern. TCGA analyses in 9,125 human cancers reveal alterations of TGF-β with CEACAM members in over 40% of CRC and correlate with a cancer stem cell signature. Mechanistic studies reveal that CEACAMs inhibit TGF-β tumor suppressor signaling by blocking TGFBR1, and promoting invasive CRC. Likewise, our TGF-β signaling-deficient mouse models spontaneously develop CRC, as well as metastases, likely modulated in part by the microbiome. Furthermore, key defects in the TGF-β pathway alter sensitivity to 5-FU and DNA cross-linking agents, such as cisplatin, through disruption of DNA repair pathways.

Conclusion: The TGF-β pathway is important in maintaining colon epithelial cell homeostasis potentially through interactions with CEACAMs and gut microbiota. When the pathway is disrupted, epithelial cells are more susceptible to transformation and invasion, potentially identifying specific populations that are more sensitive to chemotherapy such as cisplatin and 5FU.

Citation Format: Shuyun Rao, Charles Hadley King, Raja Mazumder, Shoujun Gu, Richard Amdur, Bibhuti Mishra, Lopa Mishra. Identification of chemotherapeutic resistant microbiota profile in colorectal 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 2827.
Abstract 2829: Pancreatic tumor microbiome and associated immune responses determine clinical outcomes
Authors: Riquelme Erick M. , Zhang Yu , Zhang Liangliang , Maria Montiel , Michelle Zoltan , Dong Wenli , Quesada Pompeyo , Sahin Ismet , Chandra Vidhi , Lucas Anthony San , Scheet Paul , Xu Hanwen , Hanash Samir M. , Feng Lei , Ajami Nadim , Petrosino Joseph , Peterson Christine B. , Nejman Deborah , Kim Michael P. , Sears Cynthia L. , Wood Laura D. , Maitra Anirban , Straussman Ravid , Katz Matthew , White James Robert , Jenq Robert , Wargo Jennifer , McAllister Florencia
Published: August 2019

Most patients diagnosed with pancreatic adenocarcinoma (PDAC) survive less than 5 years, but a very small subset of patients survive longer. The factors that determine the long-term survivorship remain elusive. Recently, studies have shown that bacteria can be found in PDAC which may influence therapy responses. In this study, we aimed to determine if the tumor microbiome, and its associated immune responses, can guide long-term survivorship in resected PDAC patients. Using 16S rRNA gene sequencing, we analyzed the tumor microbiome composition and immunoprofile in PDAC patients who survived less than 5 years (short term survivors, STS) versus those who survived more than 5 years (long term survivors, LTS) in two independent cohorts of patients from two institutions (MD Anderson Cancer Center and Johns Hopkins University). We found higher alpha-diversity in the tumor microbiome from LTS compared to STS PDAC patients. Additionally, we found greater densities of immune cells in the LTS compared to STS, with significant correlation with alpha-diversity. Taken together, our study demonstrates that the PDAC microbiome composition may influence the host immune response and the natural history of the disease.

E.R. and Y.Z. contributed equally to this work.

Citation Format: Erick M. Riquelme, Yu Zhang, Liangliang Zhang, Montiel Maria, Zoltan Michelle, Wenli Dong, Pompeyo Quesada, Ismet Sahin, Vidhi Chandra, Anthony San Lucas, Paul Scheet, Hanwen Xu, Samir M. Hanash, Lei Feng, Nadim Ajami, Joseph Petrosino, Christine B. Peterson, Deborah Nejman, Michael P. Kim, Cynthia L. Sears, Laura D. Wood, Anirban Maitra, Ravid Straussman, Matthew Katz, James Robert White, Robert Jenq, Jennifer Wargo, Florencia McAllister. Pancreatic tumor microbiome and associated immune responses determine clinical outcomes [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 2829.
Abstract 2837: Fusobacterium nucleatum and T cells in colorectal cancer liver metastasis
Authors: Sakamoto Yuki , Mima Kosuke , Daitoku Nobuya , Hiyoshi Yukiharu , Imai Katsunori , Iwatsuki Masaaki , Ishimoto Takatsugu , Baba Yoshifumi , Iwagami Shiro , Miyamoto Yuji , Yamashita Yoichi , Yoshida Naoya , Baba Hideo
Published: August 2019

Background: Accumulating evidence links the intestinal microbiota and colorectal carcinogenesis. Fusobacterium nucleatum has been shown to promote colorectal tumor growth and inhibit antitumor immune responses. Emerging evidence demonstrates an enrichment of Fusobacterium species in colorectal cancer live metastasis (CRLM).

Aim: To test the hypothesis that higher amount of Fusobacterium nucleatum is associated with lower density of CD8+ T-cells in CRLM.

Method: Genomic DNA was extracted from CRLM and adjacent normal liver tissues. We measured the amount of Fusobacterium nucleatum DNA in 164 CRLM tissues using a quantitative polymerase chain reaction assay. The density of CD8+ T-cells in CRLM was determined by immunohistochemical staining.

Result: Fusobacterium nucleatum was detected in 8 (4.9%) of 164 CRLM cases. A higher density of CD8+ T-cells in CRLM was significantly associated with better relapse-free survival (P =0.036). Fusobacterium nucleatum-negative cases, Fusobacterium nucleatum-positive cases were inversely associated with the density of CD8+T-cells (P =0.020).

Conclusions: The presence of Fusobacterium nucleatum is inversely associated with CD8+ T-cells density in CRLM. Upon validation, our data may have implications for preventing the formation of liver metastases in colorectal cancer through targeting intestinal microflora.

Citation Format: Yuki Sakamoto, Kosuke Mima, Nobuya Daitoku, Yukiharu Hiyoshi, Katsunori Imai, Masaaki Iwatsuki, Takatsugu Ishimoto, Yoshifumi Baba, Shiro Iwagami, Yuji Miyamoto, Yoichi Yamashita, Naoya Yoshida, Hideo Baba. Fusobacterium nucleatum and T cells in colorectal cancer liver 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 2837.
Abstract 2845: The role of PSAT1 in triple negative breast cancer metastasis
Authors: Metcalf Stephanie , Kruer Traci , Dougherty Susan , Biyik-Sit Rumeysa , Klinge Carolyn , Clem Brian
Published: August 2019

Breast cancer is the number one diagnosed cancer type among women in the United States (NCI). This disease can be stratified into different molecular subtypes, including triple negative breast cancer (TNBC), each of which can have different therapeutic options, patient prognosis, and survival outcomes. TNBC disease readily metastasizes and different processes have been implicated in the development of metastatic disease. The serine synthesis pathway (SSP) is responsible for de novo production of serine and consists of three enzymes, including phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase 1 (PSAT1). PSAT1 catalyzes the second step in this pathway, is elevated in more aggressive tumor types such as basal breast cancer (Pollari, 2011) and has clinically been associated with poorer distant metastatic free survival and overall survival (unpublished from KMPlotter) in breast cancer patients. These prior studies combined with our own preliminary data underscores the hypothesis that PSAT1 promotes the metastatic potential of triple negative breast cancer. This hypothesis was first evaluated through immunohistochemistry examination of patient samples which demonstrated that expression of PSAT1 increases with TNBC tumor grade. In vitro assays of proliferation showed no difference upon loss of PSAT1, however, metastasis (migration and invasion) was significantly inhibited upon PSAT1 suppression. In a tail-vein experimental metastasis model, suppression of PSAT1 significantly inhibited the formation of tumor nodules. Mechanistically, the relevance for de novo serine synthesis pathway was examined in vitro via suppression of PHGDH. Decreased PHGDH did not affect proliferation or the metastatic capability of either cell line. Further, addition of exogenous serine could not rescue metastatic deficiencies upon loss of PSAT1. Our results suggest that PSAT1 does contribute to metastasis in TNBC and that this affect appears to be independent of its metabolic role in serine synthesis. While studies are ongoing, this points to the potential of a non-canonical function of PSAT1 being a therapeutic target for patients with TNBC that are currently lacking treatments options.

Citation Format: Stephanie Metcalf, Traci Kruer, Susan Dougherty, Rumeysa Biyik-Sit, Carolyn Klinge, Brian Clem. The role of PSAT1 in triple negative breast 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 2845.
Abstract 2888: Targeting the fatal pediatric brain tumors AT/RT and DIPG with the DNA binding agent quinacrine
Authors: Kaur Harpreet , Guo Huizi , Green Peter , Akhtarkhavari Sepehr , Shah Smit , Eberhart Charles G. , Raabe Eric H.
Published: August 2019

Atypical teratoid/rhabdoid tumors (AT/RT) and diffuse intrinsic pontine glioma (DIPG) are incurable pediatric brain tumors. Developing new targets and novel therapeutics are urgently needed. We have previously shown that multiple primary brain tumors and cell lines express increased amounts of the epigenetic modifier high mobility group AT-hook 2 (HMGA2). HMGA2 is a DNA-binding oncoprotein that regulates transcription during normal embryogenesis and in cancer stem cells. Targeting HMGA2 using short hairpins significantly decreased AT/RT and glioma growth and increased survival of xenografted mice. We hypothesized that pharmacological inhibition of HMGA proteins using DNA minor-groove binding drugs like quinacrine will decrease AT/RT and DIPG growth due to displacement of HMGA proteins from the DNA. We used quinacrine in ten patient-derived cell lines: five AT/RT (BT37, CHLA-05, CHLA-06, BT-12, CHLA-266) and five DIPG (JHHDIPG1, SUDIPGXIII, JHHDIPG16A, SF7761, HSJD-007). Quinacrine has been used in millions of humans to treat malaria and parasitic infections, has a well-known safety profile and can penetrate the brain. Using quinacrine fluorescence as a surrogate, we can achieve therapeutically efficacious micromolar concentration of quinacrine in the mouse and zebrafish brain after oral administration without overt toxicity. In both tumor cell lines, quinacrine causes a dose-dependent reduction in growth (MTS) and proliferation (BrdU) compared to vehicle-treated cells (P<0.01). Treatment of both tumor lines with quinacrine significantly increased apoptosis (cleaved caspase-3 and cleaved PARP) compared to control cells (P<0.01). Quinacrine had no effect on growth of normal hindbrain cells. Our results suggest that minor groove binding drugs like quinacrine are a viable potential treatment strategy for these lethal tumors. Ongoing studies include validating the in vivo efficacy of quinacrine using zebrafish and mouse models of AT/RT and DIPG. Future studies are aimed at investigating the mechanism of quinacrine in these devastating tumors.

Citation Format: Harpreet Kaur, Huizi Guo, Peter Green, Sepehr Akhtarkhavari, Smit Shah, Charles G. Eberhart, Eric H. Raabe. Targeting the fatal pediatric brain tumors AT/RT and DIPG with the DNA binding agent quinacrine [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 2888.
Abstract 2898: Stochastic variation in gene expression is selected during clonal evolution of spontaneous mouse mammary tumors
Authors: Felts Sara J. , Tang Xiaojia , Keulen Virginia P. Van , Kalari Krishna R. , Pease Larry R.
Published: August 2019

Molecular and cellular diversity in cancer cells enables evolutionary processes that govern tumor progression and contributes to treatment failures, but the mechanisms governing this variability remain incompletely understood. We previously described tumor-specific epigenetic alterations in DNA devoid of canonical CpG methylation sites throughout the genomes of spontaneous breast tumors which arise in genetically uniform, yet heterozygous, [FVB X BALB/c MMTV-NeuT+] F1 mice. Those changes were detected in purified tumor DNA using a template-assisted quantitative ligation assay employing locus-specific and SNP-specific oligonucleotide genotyping probes, and the assay was subsequently shown to be sensitive to epigenetic modifications of the templates. We now describe losses of heterozygosity similarly distributed throughout the transcriptomes of tumors in this same model. We quantified expressed alleles across a population of clonal tumors and tested each expressed variant for the occurrence of allelic ratio outliers. The results revealed variegated patterns of expression in hundreds of genes, highly significantly enriched in pathways typically co-opted by tumors (Molecular Mechanisms of Cancer, P < 10-10, IPA analysis). An astounding 87% (2634 of 3044) of expressed genes that could be measured using this approach were represented in at least one tumor. Furthermore, the frequency of these outliers in any one individual tumor was found to correlate strongly with the transcriptional repression of an additional large set of non-polymorphic genes. These findings reveal underappreciated, latent mechanisms driving sporadic errors in epigenetic programming that promote repression of a multiple cis-linked transcripts. This genome-wide molecular chaos presents as dysregulated cellular homeostasis and is the foundation for heritable diversity as tumors evolve.

Citation Format: Sara J. Felts, Xiaojia Tang, Virginia P. Van Keulen, Krishna R. Kalari, Larry R. Pease. Stochastic variation in gene expression is selected during clonal evolution of spontaneous mouse mammary tumors [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 2898.
Abstract 2912: The impact of primary tumor sidedness on the effect of regorafenib in refractory metastatic colorectal cancer
Authors: Yoon Sang Eun , Hur Joon Young , Lee Su Jin , Lee Jeeyun , Park Se Hoon , Park Joon Oh , Lim Ho Yeong , Kang Won Ki , Park Young Suk , Kim Seung Tae
Published: August 2019

Recently, the sidedness of the primary tumor (right versus left) has been investigated for its ability to prognosticate and predict outcomes. We evaluated the effect of regorafenib based on KRAS mutation status and the sidedness of the primary tumor in patients with metastatic colorectal cancer (mCRC). We analyzed 135 patients with refractory metastatic colorectal cancer (mCRC) being treated with regorafenib at Samsung Medical Center, between January 2014 and January 2018. Primary tumors originating in the splenic flexure, descending colon, sigmoid colon, rectum, or proximal third of the transverse colon were defined as left-sided CRC (LC). Primary tumors originating in the appendix, cecum, ascending colon, hepatic flexure, or distal two-thirds of the transverse colon were defined as right-sided CRC (RC). Among all 135 patients, 100 (74.1%) had left sided colon cancer and 35 (25.9%) had right-sided colon cancer. No patients achieved a complete response, but four achieved a partial response, revealing a response rate (RR) of 3.0%. Thirty-seven patients had stable disease, yielding a disease control rate (DCR) of 30.4%. There was no difference in RR or DCR according to the location of the primary tumor (LC vs. RC). A significant difference in progression free survival (PFS) with regorafenib was observed between the LC and RC groups (2.6 months; 95% CI, 2.0 to 3.1 vs. 1.9 months; 95% CI, 1.6 to 2.3; P = 0.04, respectively). In a subpopulation with wild type KRAS, PFS with regorafenib was also significantly different between the LC and RC groups (2.9 months; 95% CI, 1.5 to 4.3 vs. 2.1 months; 95% CI, 0.6 to 3.6; P= 0.04). On multivariate analysis, the sidedness of the primary tumor (LC vs. RC) and the number of metastatic sites (≤1 vs. 2>) had a prognostic effect on PFS (P = 0.01 and P = 0.01, respectively). Regorafenib is a current standard treatment for CRC, but treatment outcomes may be improved if regorafenib is administered based on the appropriate biomarker.

Citation Format: Sang Eun Yoon, Joon Young Hur, Su Jin Lee, Jeeyun Lee, Se Hoon Park, Joon Oh Park, Ho Yeong Lim, Won Ki Kang, Young Suk Park, Seung Tae Kim. The impact of primary tumor sidedness on the effect of regorafenib in refractory metastatic colorectal 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 2912.
Abstract 2917: Inhibition of Annexin A6 sensitizes triple negative breast cancer cells to radiation
Authors: Nangami Gladys N. , Sakwe Amos , Ochieng Josiah
Published: August 2019

Introduction: Despite vast evidence that tumor genetics play a dominant role in determining radiosensitivity and ultimate benefit from radiation therapy (RT), current RT delivery algorithms have not successfully incorporated tumor biology. Instead, clinical decisions regarding the use of RT are still based on features of tumor aggressiveness such as stage, grade, degree of metastasis and type of surgery. We provide evidence showing that most aggressive basal-like TNBC cells characteristically expresses low levels of the Ca2+-dependent membrane-binding tumor suppressor Annexin A6 (AnxA6) as compared to mesenchymal-like TNBC cell lines. We have also shown that depletion of AnxA6 in TNBC cells induced severe morphological changes from the slow growing mesenchymal-like to rapidly growing basal-like phenotypes and that this was not only associated with enhanced anchorage independent cell proliferation, but significantly inhibited cell adhesion, motility and invasiveness. Given that rapidly proliferating cells are more radiosensitive, we hypothesized that the expression status of AnxA6 in triple negative breast cancer cells underlies their response to RT.

Materials and Methods: For clonogenic assay, cells were grown to 70-80% confluency then were allowed to settle and attach for 8 hours before being exposed to irradiation at various doses. Dishes were then incubated at 37oC in 5% CO2 in a humidified incubator to form colonies for 14 days. Colonies (50 cells or more) were stained with crystal violet and enumerated under a Fisher Stereomaster II 10X stereoscopic microscope. Radiation induced cell cycle arrest was assessed by flow cytometry.

Results: Our studies show that depletion of AnxA6, significantly increased the sensitivity of triple negative breast cancer cells via up-regulation of cell cycle pathways as demonstrated by lack of G2/M cell cycle arrest in cells with low level of AnxA6. Additionally, we demonstrate that knockdown of AnxA6 enhanced radiation induced DNA damage.

Conclusions: Our findings demonstrate that reduced expression of AnxA6 enhances radiation sensitivity of triple negative breast cancer cells.

Note: This abstract was not presented at the meeting.

Citation Format: Gladys N. Nangami, Amos Sakwe, Josiah Ochieng. Inhibition of Annexin A6 sensitizes triple negative breast cancer cells to radiation [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 2917.
Abstract 2921: A dual role of genomic instability on radiosensitivity in cancer cells
Authors: Seo Yuji , Tamari Keisuke , Takahashi Yutaka , Minami Kazumasa , Otani Keisuke , Isohashi Fumiaki , Ogawa Kazuhiko
Published: August 2019

Background: Genomic instability is a hallmark of cancer, which may lead to heterogeneity and provide an advantage on tumor survival and proliferation. However, we previously found that a greater number of genomic mutations were associated with reduced tolerance to radiation. The aim of this study is to elucidate a role of genomic instability on cellular radiosensitivity.

Materials and Methods: We used 59 cancer cell lines derived from various types of solid tumors. Radiation-induced cell death was measured by the standard colony-forming assay at the dose range of 0 to 10 Gy. Based on the resulting survival curves, the mean inactivation dose (MID) was calculated as a single value representing cellular radiosensitivity. Somatic gene aberration data for the 59 cell lines were obtained from the Catalogue Of Somatic Mutations In Cancer cell line project v.80. The genomic analysis focused on cancer-related pathways defined by Kyoto Encyclopedia Genes and Genomes. The genomic mutations included nucleotide variations (substitutions, insertions, or deletions) and copy number variations (CNV). Only pathogenic mutations were selected and neutral mutations were disregarded according to the functional analysis through hidden Markov model. Both gain and loss in CNVs were included.

Results: There were either nucleotide variations or copy number variations in 598 genes in the 59 cancer cell lines. The mutations were found in 16 caretakers, 51 gatekeepers, 105 oncogenes, and 449 passengers. There were significant positive correlations between the MIDs and the proportions of mutations in the gatekeepers or the oncogenes to the whole mutations. Namely, radioresistant cell lines harbored gatekeeper mutations or oncogene mutations at higher proportions. Conversely, radiosensitive cell lines showed significantly higher proportions of passenger mutations. No correlation was found in between the MIDs and the proportions of caretaker mutations.

Conclusions: Genomic instability caused by caretaker mutations may result in not only increased tolerance to radiation through mutations in gatekeeper genes and oncogenes but also reduced tolerance to radiation through accumulating passenger mutations. A balance between the two opposing phenomena is a significant determinant of cancer cell radiosensitivity.

Citation Format: Yuji Seo, Keisuke Tamari, Yutaka Takahashi, Kazumasa Minami, Keisuke Otani, Fumiaki Isohashi, Kazuhiko Ogawa. A dual role of genomic instability on radiosensitivity in 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 2921.
Abstract 2929: Radiosensitization of head and neck cancer by FGFR inhibition
Authors: SenthilKumar Gopika , Miller Margot , Fisher Michael , Brennan Sean , Kaushik Saakshi , Able Lindsey , Harari Paul M. , Iyer Gopal , Kimple Randall J. , Baschnagel Andrew M.
Published: August 2019

Objective:

Fibroblast growth factor receptors are frequently amplified or overexpressed in head and neck squamous cell carcinomas (HNSCC). We assessed the potential of a selective FGFR-kinase inhibitor, AZD4547, to act as a radiosensitizer in head and neck cancer cell lines and xenografts.

Methods:

A panel of head and neck cancer (n=10) and normal oral mucosa (HTE) cell lines were screened for FGFR1, 2, and 3 gene copy number, RNA expression, and protein. Sensitivity to the FGFR inhibitor AZD4547, alone or in combination with radiation, was assessed using proliferation and clonogenic survival assays. Putative mechanisms of radiosensitization were investigated by immunoblot and by assessing for DNA repair capacity, cell cycle effects, apoptosis, senescence, and autophagy. Tumor response of cell line xenografts and patient derived xenografts was assessed in vivo.

Results:

Cells demonstrated varying responses to FGFR inhibition but this did not correlate with FGFR gene copy number, mRNA expression, or protein expression. Three cell lines which responded to AZD4547 alone (CCL30, Tu-138, and SCC6) were selected for further investigation. TU-138 and CCL30 featured high FGFR expression and were radiosensitized by AZD4547 in vitro. SCC6 was not. Cell lines which were insensitive to FGFR inhibition (including HTE) did not demonstrate radiosensitization by AZD4547. In the sensitive cell lines, enhanced p-MAPK inhibition was seen in a time-dependent manner following drug treatment. When added to radiation, AZD4547 resulted in increased apoptosis, autophagy, and senescence but did not alter the kinetics of DNA repair as assessed by resolution of gH2AX foci. No difference in the cell cycle distribution for irradiated cells treated with or without the addition of AZD4547 was seen. Treatment of two in vivo tumor xenografts with AZD4547 and radiation showed significant delay in tumor growth compared to treatment with radiation or drug alone.

Conclusion:

Our findings indicate that AZD4547 can augment the response of FGFR expressing HNSCC to radiation both in vitro and in vivo. Improved approaches to identify tumors most likely to benefit from FGFR inhibition could enable the selection of patients for combination therapy and has the potential to improve outcomes in these difficult to treat cancers.

Citation Format: Gopika SenthilKumar, Margot Miller, Michael Fisher, Sean Brennan, Saakshi Kaushik, Lindsey Able, Paul M. Harari, Gopal Iyer, Randall J. Kimple, Andrew M. Baschnagel. Radiosensitization of head and neck cancer by FGFR 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 2929.
Abstract 2935: Novel combination of repurposed drugs induces complete cell invasion arrest of glioblastoma in vitro
Authors: Oancea-Castillo Liliana , Bahr Kerstin , Régnier-Vigouroux Anne , Ackermann Maximilian , Gabriel Isaac R. , Pereles Samuel T. , Li Madeleine M. , Lowitt Dana W. , Li William W. , Li Vincent W.
Published: August 2019

Introduction: Glioblastoma multiforme (GBM) is an aggressive and lethal cancer with a poor prognosis even after conventional treatment (surgery, radiation, chemotherapy). Temozolomide (TMZ) is a standard cyotoxic agent used, despite resistance leading to recurrence. Therefore, additional strategies for targeting the tumor environment are needed. We demonstrate a combination of approved drugs (CAD) repurposed to target GBM leads to complete arrest of GBM cell invasion. Each drug in the combination individually targets diverse tumor pathways: 1) invasion via MMP2 (doxycycline); 2) angiogenesis, inflammation, and proliferation via p53-dependent G1 cell-cycle arrest (celecoxib); 3) autophagy (tamoxifen); 4) tumor metabolism and angiogenesis (metformin).

Material and Methods: Multicellular Tumor Cell Spheroids (MTCS) were generated from two GBM cell lines (LN18, U87MG) and embedded in collagen (three-dimensional in vitro assay) and mixed with the drug combination at 2 doses + TMZ. GBM cell invasion was monitored and quantified over 96h. Flow cytometry analysis using Propidium-Iodine was performed (24h, 48h, 7h2 and 96h) to quantify the effect of the drug cocktail. Scanning Electron Microscopy (SEM) of MTCS was used to evaluate cell death at the ultrastructural level (96h after treatment).

Results: The CAD induced complete cell invasion arrest in both U87MG and LN18 MTCS regardless of drug dose or presence of TMZ. GBM cell death was observed after 96h. TMZ in combination with CAD showed a significant increase in cell death, suggesting synergism. SEM images demonstrated large-scale changes in the tumor spheroid morphology showing GBM cell death.

Conclusions: The combination of approved drugs (CAD) with TMZ can effectively halt GBM cell invasion and induce cell death in vitro. These results suggest a sensitizing effect of CAD to potentiate TMZ’s effects. Because CAD components have well established safety profiles, further investigation to define the anti-GBM mechanisms and effects on the tumor microenvironment are warranted. This CAD has potential for future therapeutic approaches. The generic nature of the drugs makes CAD an intriguing cost-effective GBM adjunctive therapy.

Citation Format: Liliana Oancea-Castillo, Kerstin Bahr, Anne Régnier-Vigouroux, Maximilian Ackermann, Isaac R. Gabriel, Samuel T. Pereles, Madeleine M. Li, Dana W. Lowitt, William W. Li, Vincent W. Li. Novel combination of repurposed drugs induces complete cell invasion arrest of glioblastoma in vitro [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 2935.
Abstract 2936: Increased PARP1-DNA binding due to autoPARylation inhibition of PARP1 on DNA rather than PARP1-DNA trapping is correlated with PARP1 inhibitor's cytotoxicity
Authors: Chen Hua-Dong , Chen Chuan-Huizi , Wang Yu-Ting , Guo Ne , Tian Yu-Nan , Huan Xia-Juan , Song Shan-Shan , He Jin-Xue , Miao Ze-Hong
Published: August 2019

PARP1 inhibitors (PARPis) have been successfully used in the clinic for cancer therapy. The mechanisms by which they elicit cytotoxicity in cancer cells remain to be clarified. Initially, inhibition of cellular polymerase activity of PARP1 (reflected as inhibition of cellular poly (ADP-ribose) (PAR) formation or PARylation) was proposed as their primary mechanism. However, either cell-free histone-based or cellular PARylation inhibition displays very low correlation with PARPis’ cytotoxicity or clinical anticancer effects. Subsequently, the Pommier’s group proposed the mechanism of PARP1-DNA trapping and demonstrated that this mechanism showed much higher correlation with PARPis’ cytotoxicity. Nevertheless, contradictory results have been reported since then. Here, we showed no significant correlation between PARP1-DNA trapping and cytotoxicity induced by PARPis. We complemented PARP1-knockout sublines with wild-type PARP1 and 11 mutants with different point mutations that affect the polymerase activity. When examining the PARPi talazoparib, the induced cytotoxicity was highly significantly correlated with cellular PARP1 polymerase activity, but not with its PARP1-DNA trapping or polymerase inhibition. Similarly, talazoparib’s PARP1-DNA trapping revealed significant correlation with the polymerase activity rather than its inhibition. Differently, however, when evaluating purified wild-type and mutated PARP1, we identified an almost linear relationship between PARPis’ inhibiting PARP1 dissociation from DNA and their cytotoxicity in 17 cancer cell lines. In contrast, no significant correlation existed between PARP1 polymerase inhibition in the histone-based systems and the cytotoxicity. After careful comparisons on different methods and detection targets, we conclude that the PARPi-mediated increase in PARP1-DNA binding by inhibiting autoPARylation of PARP1 on DNA rather than in PARP1-DNA trapping is correlated with PARPi’s cytotoxicity. Based on this conclusion, we established a new PARPi screening model that more closely predicts cytotoxicity (r=0.9984; p<0.0001).

Citation Format: Hua-Dong Chen, Chuan-Huizi Chen, Yu-Ting Wang, Ne Guo, Yu-Nan Tian, Xia-Juan Huan, Shan-Shan Song, Jin-Xue He, Ze-Hong Miao. Increased PARP1-DNA binding due to autoPARylation inhibition of PARP1 on DNA rather than PARP1-DNA trapping is correlated with PARP1 inhibitor's cytotoxicity [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 2936.