bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract GMM-056: IGF-AXIS SIGNALING DURING OVULATION IS RESPONSIBLE FOR THE STEMNESS CELL EXPANSION AND TRANSFORMATION OF FALLOPIAN TUBE FIMBRIAL EPITHELIUM
Authors: Chu Tang-Yuan , Hsu Che-Fang , Huang Hsuan-Shun
Published: June 2021

Recent studies have unveiled the fallopian tube fimbria as the major tissue-of-origin and incessant ovulation as the main etiological risk factor of ovarian high-grade serous carcinoma (HGSC) but the mechanism of cancer initiation remains elusive. In a series of study we have found a subset of preovulatory follicular fluids (FF) contain high level of ROS that induce DNA double strand breaks as well as apoptosis to the fimbrial epithelial cells in vitro and in vivo. We also found hemoglobin in pelvis, most likely contributed by retrograde menstruation of previous cycles, reduces the ovulatory ROS level extracellularly and results in a shifting from the apoptotic to the survival fate of ROS-stressed fimbrial epithelial cells. These initiating factors in FF, although may contributes to the TP53 mutation and other early genetic hits in the genesis of HGSC, cannot fully transform the immortalized fimbrial epithelial cells, with loss of p53 and Rb.

In this study, we demonstrated that IGF axis proteins, including IGFBP2- and IGFBP6-bound IGF2 as well as the IGFBP-lytic enzyme PAPP-A are abundantly present in ovulatory FF, and disclosed their effect on the fallopian tube fimbrial epithelium. Upon engaging with glycosaminoglycans (GAG) on the membrane of fimbrial epithelial cells, PAPP-A cleaves IGFBPs and releases bioactive IGF2 in close proximity to its receptor IGF-1R. This leads to stemness activation and clonal expansion of primary and immortalized fimbrial epithelial cells, and to malignant transformation of p53/Rb- and p53/CCNE1-disrupted fimbrial secretory cells. By antibody depletion, we proved each component of this IGF axis is essential and confers the majority of the transformation/regeneration activities in FF. Two signaling pathways, IGF-1R/ AKT/mTOR and IGF-1R/AKT/NANOG, are responsible for the phenotypes. Among them, IGF-1R and NANOG were critical since blocking their expression or function lead to a complete loss of the transformation.

Given that ovulation is an acute inflammatory process inevitably damaging the ovarian surface and the fimbriae, IGF axis in FF takes a role of tissue repair and, in situations when the ROS-induced TP53/Rb mutations accumulated in stem cells, may lead to carcinogenesis of the fallopian tube fimbria.

Citation Format: Tang-Yuan Chu, Che-Fang Hsu, Hsuan-Shun Huang. IGF-AXIS SIGNALING DURING OVULATION IS RESPONSIBLE FOR THE STEMNESS CELL EXPANSION AND TRANSFORMATION OF FALLOPIAN TUBE FIMBRIAL EPITHELIUM [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-056.
Abstract GMM-059: SHEAR STRESS DOWNREGULATION OF MIR-199A-3P DRIVES CHEMORESISTANCE IN OVARIAN CANCER CELLS
Authors: Li Shan-Shan , Ip Carman K. M. , Shum Ho-Cheung , Wong Alice S. T.
Published: June 2021

Ovarian cancer is leading cause of deaths among all gynecological malignancies. The presence of intrinsic and acquired drug resistance are major challenges in the treatment and clinical management of ovarian cancer. Ovarian cancer cells typically cluster into tumor spheroids and float in the ascitic fluid, which are characteristic of the aggressiveness of these tumor cells. We have recently developed a three-dimensional microfluidic platform with tumor spheroids and continuous fluidic flow to closely emulate the physiological condition in the ascites of ovarian cancer patients. Using this model, we showed for the first time that clinically relevant levels of ascitic shear stress induced drug resistance in ovarian tumor spheroids. Such chemoresistance was mediated through the increased expression of ABC-binding cassette transporter G2 and P-glycoprotein. By profiling the microRNAs (miRNAs) expression patterns under flow conditions, we identified miR-199a-3p as a critical mechanosensitive miRNA that was downregulated under shear stress through regulating the miRNA biogenesis machinery. miR-199a-3p expression was found to be inversely correlated with enhanced drug resistance properties and chemoresistant ovarian cancer sublines. Ectopic expression of miRNA-199a-3p could reverse the shear stress-induced expression of ABC-binding cassette transporter G2 and P-glycoprotein in ovarian tumor spheroids, confirming that the effect was miR-199a-3p specific. Taken together, these findings highlight the importance of shear stress-mediated decrease of miR-199a-3p in the regulation of drug response in ovarian cancer, which provide new insights in the understanding of cancer biology and potential effective treatment.

Citation Format: Shan-Shan Li, Carman K. M. Ip, Ho-Cheung Shum, Alice S. T. Wong. SHEAR STRESS DOWNREGULATION OF MIR-199A-3P DRIVES CHEMORESISTANCE IN OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-059.
Abstract NT-086: PRELIMINARY IDENTIFICATION OF LACTATE DEHYDROGENASE INHIBITORS TOWARDS ANTICANCER DRUG DEVELOPMENT
Authors: Emmanuel Adegbite , Sanya Joseph O , Olubiyi Olujide O
Published: June 2021

In tumor cells undergoing rapid cellular division, significantly increased quantities of lactic acid are produced in an anaerobic respiration via the Cori cycle. While this produces a lower of the pH in the local environment, the hepatic conversion of the generated lactate into glucose places a huge energy demand on the body which makes the patient weaker and results in cancer cachexia in all ovarian malignancies. Thus, instead of producing acetyl CoA, the dividing tumorous cells synthesize lactic acid catalyzed by the enzyme lactate dehydrogenase (LDH). LDH's involvement in tumor initiation and metabolism primarily involves a state of fermentative glycolysis catalyzed by the A form of the enzyme which allows tumorous cells convert the majority of their glucose stores into lactate even under anaerobic conditions which invariably shifts the utilization of glucose metabolites from simple energy production to an active promotion of accelerated cell growth and replication. This makes LDH a vital target for malignant ovarian drug development. And in the present work a combination of virtual screening, database scouting and biophysical analysis of binding site properties have been employed in analysis the interaction of about 30,000 compounds with LDH. Using a synthetic NADH inhibitor, as a reference, only four compounds were found to demonstrate stronger binding features than the inhibitor. This preliminary in silicon screening represents the foundational effort in a ovarian cancer drug discovery project aimed at generating specific inhibitors of LDH for use in ovarian cancer therapeutics.

Note: This abstract was not presented at the symposium.

Citation Format: Adegbite Emmanuel, Joseph O Sanya, and Olujide O Olubiyi. PRELIMINARY IDENTIFICATION OF LACTATE DEHYDROGENASE INHIBITORS TOWARDS ANTICANCER DRUG DEVELOPMENT [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-086.
Abstract NT-097: QUANTITATIVE HIGH-THROUGHPUT SCREENING USING AN ORGANOTYPIC MODEL IDENTIFIES TWO KINASE INHIBITORS THAT INHIBIT OVARIAN CANCER METASTASIS
Authors: Kenny Hilary A. , Lal Madhu , Shen Min , Nahotko Dominik , Fazal Sarah , Chen Siquan , Chiang Chun-Yi , Kara Betul , Yamada S. Diane , Brimacombe Kyle , Marugan Juan , Ferrer Marc , Lengyel Ernst
Published: June 2021

The cancer cells, stromal cells and stroma in the tumor microenvironment contribute to cancer metastasis and drug resistance. Therefore we applied an organotypic, robust and reliable assay for quantitative high throughput screening (qHTS) in drug discovery. This 1536-well HTS culture contains primary human mesothelial cells, fibroblasts, fibronectin and collagen type I and reproduces the human ovarian cancer (OvCa) metastatic microenvironment. The qHTS assay identifies small molecule compounds that inhibit OvCa adhesion/migration/invasion to the organotypic metastatic microenvironment.

Over 44,000 small molecules were screened in the primary qHTS assay. A counter screen was performed to eliminate any compounds toxic to the mesothelial cells or fibroblasts within the metastatic microenvironment. The activity of hit compounds was confirmed using five OvCa cell lines, and validated in secondary in vitro and in vivo biological assays. The active compounds directly inhibit at least two of three OvCa functions: adhesion, invasion and growth. In vivo, these compounds prevent OvCa adhesion/invasion and metastasis, and improve survival in mouse models.

Collectively, these data indicate that the three compounds, two tyrosine kinase inhibitors and one novel compound, identified using an complex organtoypic culture of the tumor microenvironment for qHTS are potential therapeutics for OvCa metastasis.

Citation Format: Hilary A. Kenny, Madhu Lal, Min Shen, Dominik Nahotko, Sarah Fazal, Siquan Chen, Chun-Yi Chiang, Betul Kara, S. Diane Yamada, Kyle Brimacombe, Juan Marugan, Marc Ferrer and Ernst Lengyel. QUANTITATIVE HIGH-THROUGHPUT SCREENING USING AN ORGANOTYPIC MODEL IDENTIFIES TWO KINASE INHIBITORS THAT INHIBIT OVARIAN CANCER METASTASIS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-097.
Abstract NT-100: PARPI-INDUCED ALDH1A1 EXPRESSION CONTRIBUTES TO PARPI RESISTANCE IN OVARIAN CANCER CELLS
Authors: Liu Lu , Cai Shurui , Han Chunhua , Benerjee Ananya , Wu Dayong , Cui Tiantian , Xie Guozhen , Zheng Yanfang , Wang Qi-En
Published: June 2021

Ovarian cancer (OC) is one of the most lethal female malignancy which accounts for just 2.5% of female cancer cases but 5% of deaths because of low survival. 90% of OC are epithelial ovarian cancer (EOC), with an overall 5-year relative survival rate of 47% and only 29% for patients diagnosed with distant-stage. 20% of OC cases are estimated to be due to inherited mutations that confer elevated risk, especially cancer susceptibility genes BRCA1 and BRCA2. PARP inhibitors (PARPi) are novel and promising cancer-targeted drugs. PAPRi are approved by FDA for clinical treatment of advanced EOC patients with BRCA1/2 gene mutation. However, patients gradually gained resistance to PARPi with continuously increased recurrence rate (>90%). Thus, understanding the mechanism underlying PARPi resistance is an urgent need for improving the PARPi efficacy. Aldehyde dehydrogenase (ALDH) activity is considered as a cancer stem cell (CSC) marker and also relative to drug resistance. However, the relationship between ALDH activity and PAPPi resistance remains unclear. In this study, we generated two olaparib-resistant EOC cell lines by continuously treating BRCA2-mutated PEO1 and Kuramochi cell lines for 6 months, and found that these resistant cell lines exhibited higher ALDH activity compared to their corresponding parent cell lines. In addition, short-term treatment of PEO1 and Kuramochi cells with olaparib (7 days) also increased the ALDH+ cell population in these cells, and olaparib-induced ALDH--to-ALDH+ conversion contributed to the expansion of the ALDH+ cell population after olaparib treatment. qRT-PCR analysis demonstrated that ALDH1A1 is the major gene in the ALDH gene family that was induced by olaparib. Overexpression of ALDH1A1 increased olaparib resistance in a panel of EOC cells lines including both BRCA2-muated and BRCA2-wild type cell lines. In summary, our data indicate that olaparib is able to induce ALDH1A1 gene expression, which results in the enhanced ALDH activity. The enhanced ALDH activity can contribute to olaparib resistance in BRCA2-mutated EOC cells.

Citation Format: Lu Liu, Shurui Cai, Chunhua Han, Ananya Benerjee, Dayong Wu, Tiantian Cui, Guozhen Xie, Yanfang Zheng, and Qi-En Wang. PARPI-INDUCED ALDH1A1 EXPRESSION CONTRIBUTES TO PARPI RESISTANCE IN OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-100.
Abstract NT-117: INHIBITION OF PARG, SENSITIZES OVARIAN CANCER CELLS TO PARP INHIBITORS AND DNA DAMAGING AGENTS
Authors: Matanes Emad , Baloch Tahira , Octeau David , Kessous Roy , Kogan Liron , Laskov Ido , Gotlieb Walter , Yasmeen Amber
Published: June 2021

BACKGROUND: Poly(ADP-ribose) glycohydrolase (PARG) is responsible poly(ADP-ribose) (PAR) catabolism, which is synthesized by poly(ADP-ribose) polymerases (PARPs) at the site of DNA single-strand breaks (SSB). Faulty PAR formation or disintegration inhibits SSB repair. PARP inhibitors (PARPi) exploit the synthetic lethality between SSB repair and homologous recombination (HR) double strand break (DSB) repair. The most effective PARPi traps PARP at the SSB site, causing a double strand break during DNA synthesis that the cell cannot repair. The trapping of PARP can also be achieved through PARG inhibition. Due to the high rate of HR defects in epithelial ovarian cancer, the aim of this study is to evaluate the effect of a PARG inhibitor (PARGi) on epithelial ovarian cancer cell lines, alone and in combination with PARPi or cisplatin.

METHODS: PARG protein levels were assessed in 74, unselected, snap-frozen, tumors kept in our bio-bank by western blotting and immuno-histochemistry (IHC), as well as in the TCGA database. PARG was knocked down in two cell lines resistant to PARP inhibition, OVCAR3 and SKOV3. The knockdowns were subjected to cell migration and cell proliferation assays, as well as single cell analysis. BRCA1 mutated and BRCA1 wild-type cell lines were exposed to clinically relevant doses of PARGi, PARPi, or cisplatin, separately or in various combination. Therapeutic efficacy was assessed using colony formation assay. Western Blotting was used to detect the levels of PARG and PARP proteins in the cell lines.

RESULTS: PARG mRNA was expressed in 30% of tumors in TCGA. PARG protein was also detected in 30% of the biobank tumors analyzed. PARG knockdowns exhibited reduced rates of cellular proliferation and significant G2/M cell cycle arrest. In PARG over expressed ovarian cancer cell lines, PARG inhibitor similarly reduced cell migration (OVCAR3 and SKOV3: 75% reduction, SNU-251: 48% reduction).

CONCLUSION: PARG inhibition appears to be a viable, complementary strategy to PARP inhibition in HR-deficient cancers. The effect of BRCA1 on the efficacy of PARG inhibition, as well as various treatment combinations, are currently under investigation.

Citation Format: Emad Matanes, Tahira Baloch , David Octeau, Roy Kessous, Liron Kogan, Ido Laskov, Walter Gotlieb, Amber Yasmeen. INHIBITION OF PARG, SENSITIZES OVARIAN CANCER CELLS TO PARP INHIBITORS AND DNA DAMAGING AGENTS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-117.
Abstract NT-118: SEQUENTIAL THERAPEUTIC TARGETING OF OVARIAN CANCER HARBORING DYSFUNCTIONAL BRCA1
Authors: Baloch Tahira , Kessous Roy , Octeau David , Kogan Liron , Laskov Ido , Witcher Michael , Gotlieb Walter H. , Yasmeen Amber
Published: June 2021

BACKGROUND: Ovarian cancer is the most lethal gynecologic cancer. High grade serous ovarian cancer (HGSC) is the most common and deadly histological subtype. The current standard treatment protocol involves primary debulking surgery followed by platinum-based combination chemotherapy. PARP inhibitors(PARPi) are the first approved personalized treatments used in BRCA1-mutated recurrent ovarian cancer patients and have shown promising clinical results. Previously published data in collaboration with Dr. Witcher's lab, we described a significant reduction in PARP1 protein levels in patients after giving standard carboplatinum-paclitaxel chemotherapy that is effecting the clinical efficacy of PARP inhibitors in clinical trials. PARP inhibitors are currently administered after standard chemotherapy, when PARP levels are the lowest which was clearly shown in the previous published paper. Applying novel strategy and following the sequence of administration, giving PARP inhibitors first followed by standard chemotherapy might improve response rates. This study aims to evaluate this strategy (in vitro) in the pre-clinical models.

METHODS: BRCA1 mutated (UWB1.287, SNU-251), epigenetically silenced (OVCAR8), and wild-type BRCA1 (OVCAR3, SKOV3, A2780P & A2780R) cell lines were exposed to clinically relevant doses of PARPi, either followed by standard chemotherapy, or the inverse sequence. Therapeutic efficacy was assessed using colony formation assay. Apoptotic index was evaluated by cell cycle analysis and apoptotic assays using flow cytometry. Western Blotting was used to detect the levels of relevant apoptotic and cell cycle proteins.

RESULTS: Exposure to PARPi prior to standard chemotherapy sensitized BRCA1 mutated or epigenetically silenced BRCA1 cell lines to lower doses of Cisplatin (CP) or Paclitaxel (PT). Similarly, pre-treatment with PARPi prior to chemotherapy induced apoptosis more effectively in the same cell lines. Similar results were observed in BRCA1 wild-type cell lines and cell lines in which BRCA1 functionality was restored.

CONCLUSION: Pre-treatment of cell lines with PARPi followed by standard chemotherapy is more efficient (in vitro) in inhibiting growth and inducing apoptosis than the present sequence of chemotherapy followed by PARPi.

Citation Format: Tahira Baloch, Roy Kessous, David Octeau , Liron Kogan, Ido Laskov, Michael Witcher, Walter H. Gotlieb and Amber Yasmeen. SEQUENTIAL THERAPEUTIC TARGETING OF OVARIAN CANCER HARBORING DYSFUNCTIONAL BRCA1 [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-118.
Abstract TMIM-064: AMPKA-LIKE PROTEINS IN OVARIAN CANCER TUMORIGENESIS AND NECROPTOSIS
Authors: Jamroze Anmbreen , Chesnokov Mikhail , Chefetz Ilana
Published: June 2021

In our previous research we characterized novel ALDH1A inhibitors (1A1, 1A2, 1A3) 673A that specifically target Ovarian Cancer Stem cells (OvCSC) and trigger cell programmed necrosis (necroptosis). Following ALDH1A inhibition CD133+ (A2780) FACS sorted cells we detected increase in phospho LKB1 while its major downstream target AMPKa did not exhibit changes in phosphorylation level. In addition to AMPKa, which is most known downstream target of LKB1, there are 11 AMPKa-like proteins that can be phosphorylated by LKB1. These proteins have been studied mostly in brain development.

To detect AMPKa-like relevancy to high grade serous ovarian cancer, we next analyzed TCGA data. Surprisingly we identified many alterations in all 12 genes, including LKB1 (STK11).

We only focused on alterations that exhibit gene amplifications or mRNA upregulation. Based on TCGA data, all AMPKa-like genes have many alterations in ovarian tumors suggesting importance of these genes to ovarian cancer tumorigenesis. We next continued to analyze combinations of any two genes to test their co-occurrence or mutual exclusivity. We detected 9 gene combinations, in which amplification or mRNA upregulation in AMPKa-like genes co-occur (p<0.5) in patient tumors. We next validated expression of AMPKa-like genes in ovarian cancer cell lines and confirmed their expression in PEO-4, Ovcar8, and Ovsaho. We next treated Ovsaho, PEO4 and OvCAR8 cells with ALDH1A inhibitor 673A for 8 and 14 hr, and profiled expression of AMPKa-like genes following ALDH1A inhibition. We detected significant changes in AMPKa-like genes, suggesting their role in cell programmed necrosis.

To confirm our bioinformatic findings, we established cell lines that mimic patient tumors with most frequent co-occurrence of AMPKa genes. We have been studying these cell lines in terms of cell proliferation, stemness and role in cell death.

Citation Format: Anmbreen Jamroze, Mikhail Chesnokov, Ilana Chefetz. AMPKA-LIKE PROTEINS IN OVARIAN CANCER TUMORIGENESIS AND NECROPTOSIS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-064.
Abstract TMIM-068: TARGETING ER STRESS RESPONSES TO UNLEASH THERAPEUTIC IMMUNITY AGAINST OVARIAN CANCER
Authors: Cubillos-Ruiz Juan R
Published: June 2021

Harnessing the intrinsic ability of our immune system to eliminate malignant cells represents the most promising new anti-cancer strategy since the development of chemotherapy. While cancer immunotherapy has been designated a scientific breakthrough, tumor-induced immunosuppression still represents a major impediment to the success of this new approach in the vast majority of cancer patients. We found that ovarian cancer inhibits the development of protective anti-tumor immunity by inducing a state of continued “Endoplasmic Reticulum (ER) Stress” in tumor-associated dendritic cells (tDCs). Sustained activation of the IRE1-XBP1 arm of the ER stress response in DCs was necessary for the aggressive and accelerated progression of primary and metastatic ovarian cancers in various preclinical models of disease. Mechanistically, hyperactive XBP1 disrupted crucial metabolic pathways in tDCs and caused severe immune cell dysfunction at tumor sites. Accordingly, DC-specific XBP1 deletion or selective nanoparticle-mediated XBP1 silencing in tDCs restored their immunostimulatory activity in situ and extended survival by evoking protective T cell-mediated anti-tumor immunity. Our findings uncover a new regulatory role for XBP1-driven signaling in DCs of the tumor microenvironment and suggest that targeting aberrant ER stress responses may represent a new strategy to unleash protective immune responses against ovarian cancer.

Citation Format: Juan R, Cubillos-Ruiz. TARGETING ER STRESS RESPONSES TO UNLEASH THERAPEUTIC IMMUNITY AGAINST OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-068.
Abstract TMIM-070: APELIN PROMOTES OMENTAL METASTASIS OF OVARIAN CANCER CELLS
Authors: Dogra Samrita , Neelakantan Deepika , Patel Maulin Mukeshchandra , Griesel Beth , Olson Ann , Lupu Florea , Wool Sukyung
Published: June 2021

PURPOSE: Ovarian cancer (OvCa) is mainly metastasized to the peritoneal cavity and omentum, an organ primarily composed of adipocytes. Adipocytes produce adipokines including apelin involved in initiating angiogenesis and promote the initial homing of tumor cells to omentum through adipokine secretion. Apelin and its receptor APJ mediates glucose/energy metabolism and angiogenesis. The study objective is to assess the functional role of apelin/APJ pathway in omental metastasis of OvCa and associated benefits from antagonizing this pathway as a novel treatment strategy against OvCa metastasis.

METHODS: Mouse adipocyte cell line 3T3-L1 were used to obtain adipocyte-derived conditioned media (adipo-CM). Apelin concentrations in adipo-CM were quantified using Western blot and ELISA. Migration and invasion of human OvCa cell lines (OVCAR-5APJ and OVCAR-8) were determined in vitro in the presence of adipo-CM. In vivo homing and ex vivo adhesion assays were performed to study the role of apelin/APJ pathway in attracting and attaching APJ-overexpressing OvCa cells to the omentum.

RESULTS: Apelin expression was 2.5 fold higher in mature adipocytes compared to that in pre-adipocytes. Mature adipocytes secreted 0.8-1 ng/mL of apelin in the CM. In vivo, high APJ expression increased 'homing-in' of OvCa cells by 2.75-fold to the omentum. Adipo-CM increased transwell migration (3-3.5 fold) and invasion (3.5-4 fold) of OvCa cells in vitro. Adhesion of APJ high expression OvCa cells to mice omentum ex vivo increased by 1.5 fold. These apelin-induced pro-metastatic effects were reversed by apelin-specific antagonist (F13A) in a dose-dependent manner.

CONCLUSION: We found that apelin/ APJ pathway potentially promotes OvCa metastasis to omentum and F13A effectively inhibited apelin-induced effects.

Citation Format: Samrita Dogra, Deepika Neelakantan, Maulin Mukeshchandra Patel, Beth Griesel, Ann Olson, Florea Lupu, and Sukyung Woo1. APELIN PROMOTES OMENTAL METASTASIS OF OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-070.
Abstract TMIM-076: OMENTAL MACROPHAGES REGULATE OVARIAN CANCER METASTATIC COLONIZATION THROUGH THE CCL6-CCR1 SIGNALING AXIS
Authors: Krishnan Venkatesh , Tallapragada Supreeti , Schaar Bruce , Chanana Anita , Rinker-Schaeffer Carrie , Dorigo Oliver
Published: June 2021

BACKGROUND: Metastatic ovarian cancer remains an urgent clinical problem. The homing and invasion of cancer cells into the omental adipose tissue, which is the preferred site of ovarian cancer metastasis, is a critical step in disease progression. Omental adipose tissue contains adipocytes, blood vessels, and clusters of leukocytes known as milky spots. We have previously demonstrated in several mouse models that intraperitoneally injected ovarian cancer cells localize to the omentum and specifically to the milky spots. However, we found that B, T, or NK cells were not required for omental colonization. We hypothesize that macrophages within the milky spots play a crucial role in promoting ovarian cancer progression.

METHODS AND RESULTS: Depleting macrophages disrupts cancer cells' localization to the omentum. This result supports our hypothesis that macrophages play an essential role in attracting ovarian cancer cells to the omental milky spots. Correspondingly, factors secreted by omental macrophages promote ovarian cancer migration in vitro, in contrast to factors secreted by macrophages isolated from other peritoneal adipose tissues. In order to understand the specific mechanism(s) that regulate metastatic colonization of the omentum, we performed RNA-Seq of CD45+CD11b+F4/80+ flow-sorted macrophages from the omentum and the mesenteric fat of naïve and cancer-bearing mice. We found that omental macrophages have a distinct and dynamic gene expression pattern even when compared to a very similar cell type. The chemokine CCL6 is one of the most highly upregulated genes during metastatic colonization. The human homolog of CCL6 is CCL23 and is also expressed by human omental macrophages. Genomic inactivation of CCR1, the gene encoding receptor for CCL6 in mice and CCL23 in humans, in mouse ovarian cancer cells abolishes their ability to home to omental milky spots. Our findings establish a role for chemokine signaling in the early colonization of the omentum by ovarian cancer.

CONCLUSION: We demonstrate that omental milky spots are the preferential sites for cancer colonization of peritoneal adipose. Further, we have identified omental macrophages as the critical mediators of colonization via the CCL6/CCR1 chemokine axis. Future studies are focused on understanding the cancer cell-macrophage interactions that can be targeted therapeutically to disrupt metastatic growth and extend disease-free survival.

Citation Format: Venkatesh Krishnan, Supreeti Tallapragada, Bruce Schaar, Anita Chanana, Carrie Rinker-Schaeffer, Oliver Dorigo. OMENTAL MACROPHAGES REGULATE OVARIAN CANCER METASTATIC COLONIZATION THROUGH THE CCL6-CCR1 SIGNALING AXIS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-076.
Abstract A06: Direct and indirect effects of low-dose radiation on Tregs and antitumor efficacy among diverse tumor models
Authors: Simon Samantha , Garnett-Benson Charlie
Published: June 2021

The impact of radiation on TREG cells remains controversial. Radiation has been shown by our lab, and others, to alter the phenotype of human tumor cell by enhancing their expression of the co-stimulatory molecules OX-40L and 4-1BBL. Both OX-40 and 4-1BB signaling have been reported to influence TREG frequency and function, and we hypothesized that radiation-induced changes in expression of these molecules could influence the frequency of TREG cells within tumors. We evaluated three widely used murine tumor models for these experiments. 4T1 (mammary), MC38 (colon), or CT26 (colon) cells were implanted s.c. into mice and treated locally with 8-10Gy of radiation. Several days after treatment the frequency of tumoral T cells, including CD4+Foxp3+ TREG cells, was evaluated by fluorescent IHC and flow cytometry. We found that radiation differentially impacted the frequency of TREGS among the three tumor models evaluated and appeared to correlate with expression levels of 4-1BBL and OX-40L on the tumor cells post-IR. The level of tumor control post-RT also mirrored expression levels of 4-1BBL and OX-40L on tumor cells. Interestingly, 4T1 tumors contained more total CD4+ cells within tumors, but contained less TREG cells within the CD4 population, after radiation as compared to MC38 tumors. 4T1 tumor-bearing mice also contained more CD4+41BB+ cells as compared to MC38 tumor-bearing mice. These differences may contribute to differences in the therapy responses of various murine models utilizing radiation and may serve as useful biomarker to predict antitumor responses post-IR.

Citation Format: Samantha Simon, Charlie Garnett-Benson. Direct and indirect effects of low-dose radiation on Tregs and antitumor efficacy among diverse tumor models [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A06.
Abstract A07: Assessment of concordance among 22C3, SP263, and SP142 immunohistochemistry assay for PD-L1 expression in non-small cell lung cancer
Authors: Jung Chi Young , Kim Eun Jin , Sung Woo Jung
Published: June 2021

Background: PD-L1 expression, as determined by immunohistochemistry (IHC), is the most commonly use predictive biomarker for anti-PD-1 and anti-PD-L1 agents in currently available in clinical practice. However, multiple antibodies have been utilized in IHC assays and interpretation of their results has not been standardized. Recently, several studies have compared different antibodies and IHC systems for PD-L1 tests. We aimed to evaluate the similarity and concordance between three validated, commercially available PD-L1 IHC assays for non-small cell lung cancer (Dako 22C3, Ventana SP263, and Ventana SP142).

Methods: We evaluated 219 samples from patients with non-small cell lung cancer at the Daegu Catholic University Medical Center between June 2017 and July 2018. Each tumor sample was stained with PD-L1 IHC 22C3, SP263, and SP142. PD-L1 expression was scored at different cut-off levels for each IHC antibodies (22C3 assay: <1%, 1-49%, and ≥50%, SP263: <10%, ≥10 and <25%, and ≥25%, SP142: <1%, 1-4%, 5-49%, and ≥50%).

Results: Among the 219 samples, three different antibodies showed well correlation for PD-L1 expression (22C3 vs. SP263; r=0.896, p<0.001, 22C3 vs. SP142; r=0.750, p<0.001, SP263 vs. SP142; r=0.728, p<0.001). 22C3 IHC assay produced the similar results with SP263 IHC assay (Kappa value=0.510, p<0.001). However, 22C3 vs. SP263 and SP263 vs. SP142 showed poor concordance (Kappa value=0.171, p=0.004, and Kappa value=0.240, p<0.001, respectively).

Conclusions: 22C3, SP263, and SP142 IHC assays showed good correlation for PD-L1 expression. 22C3 IHC assay showed good concordance with SP263, but SP142.

Citation Format: Chi Young Jung, Eun Jin Kim, Woo Jung Sung. Assessment of concordance among 22C3, SP263, and SP142 immunohistochemistry assay for PD-L1 expression in non-small cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A07.
Abstract A08: Adenovirus coding for TNF-α and IL-2 proteins mediates abscopal effect in mice receiving anti-PD1 immunotherapy
Authors: Quixabeira Dafne C.A. , Cervera-Carrascón Víctor , Havunen Riikka , Siurala Mikko , Hemminki Akseli
Published: June 2021

Background: Treatment of multiple tumors and metastasis remains a challenge for current therapeutic approaches in cancer treatment. Some responses in noninjected metastases were described in the middle of the last century after using local radiotherapy in breast cancer patients. This phenomenon was named abscopal effect. Nowadays, this effect is well known to be elicited by systemic adaptive immune responses against tumor cells. Of note, it has not been fully reproducible in the clinic mainly due to the suppressive microenvironment surrounding cancer cells. The systemic use of immune checkpoint inhibitors, such as anti-CTLA-4 and anti-PD-1, has shown promise in the treatment of many tumors, but a minority of patients respond. Oncolytic virotherapy is a promising strategy that has emerged in the last few decades. It is able to prime the host immune system against tumor epitopes, thus theoretically complementing aPD1 therapy in an appealing manner. The challenge with oncolytic immunotherapy is that not all metastases can usually be injected. Therefore, it is of importance to study if local treatment can induce distant responses. While our previous work has shown synergy between oncolytic adenovirus and aPD1, here we sought to establish if the synergy extends to noninjected tumors.

Aim: In the present study we aimed to assess if local adenovirus injection can impact also noninjected tumors in animals receiving aPD1 therapy.

Methods: We utilized a murine melanoma model (B16.OVA) in which each mouse has two tumors, where only one tumor receives local virotherapy and the secondary tumor is studied for possible systemic effects following local injection.

Results: Improvement in the overall survival was seen in the group using both therapies (aPD-1 plus virus) compared to the single therapies alone. As well, secondary tumor growth was better controlled in that group. Further information, including the final survival curve, tumor growth and immunologic mechanism-of-action data, will be presented.

Conclusion: These two cancer immunotherapeutics seem to be a promising dynamic approach that may increase the life expectancy and cure the patients suffering from metastatic cancer when translated to the clinic, besides minimizing considerably the toxicity due to the specificity of such approach, and finally improving patients’ quality of life during the treatment.

Citation Format: Dafne C.A. Quixabeira, Víctor Cervera-Carrascón, Riikka Havunen, Mikko Siurala, Akseli Hemminki. Adenovirus coding for TNF-α and IL-2 proteins mediates abscopal effect in mice receiving anti-PD1 immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A08.
Abstract A32: The SUV39H1-H3K9me3 pathway represses cytotoxic T lymphocyte effector expression to confer colon carcinoma immune escape
Authors: Lu Chunwan , Yang Dafeng , Klement John D. , Oh Kyu , Savage Natasha M. , Waller Jennifer L. , Colby Aaron H. , Grinstaff Mark W. , Oberlies Nicholas H. , Pearce Cedric , Xie Zhiliang , Kulp Samuel , Coss Christopher , Phelps Mitch A. , Albers Thomas , Lebedyeva Iryna O. , Liu Kebin
Published: June 2021

Despite the presence of cytotoxic T lymphocytes (CTLs) in the tumor microenvironment, the majority of immunogenic human colon cancers do not respond to immune checkpoint inhibitor immunotherapy and microsatellite instable (MSI) tumors are not naturally eliminated. The molecular mechanism underlying the inactivity of tumor-infiltrating CTLs is unknown. We report here that CTLs are present in both MSI and microsatellite stable (MSS) colon tumors. The expression of the H3K9me3-specific histone methyltransferase SUV39H1 is significantly elevated in human colon carcinoma as compared to normal colon tissues. Using a mouse colon carcinoma model, we further determined that tumor-infiltrating CTLs in the colon tumor microenvironment express high levels of SUV39H1. To target SUV39H1 in the tumor microenvironment, a virtual chemical library was screened based on the SET domain structure of human SUV39H1 protein. Functional enzymatic activity assays identified a small molecule that inhibits SUV39H1 enzymatic activity. Based on the structure of this small molecule, we modified it and chemically synthesized a novel small molecule, termed F5446, which has an EC50 of 0.496 μM for SUV39H1 enzymatic activity. H3K9me3 is enriched in the promoters of GZMB, PRF1, FASLG and IFNG in quiescent T cells. F5446 inhibits H3K9me3, thereby upregulating expression of these effectors in tumor-infiltrating CTLs and suppressing colon carcinoma growth in a CD8+ CTL-dependent manner in vivo. Our data indicate that SUV39H1 represses CTL effector expression and, in doing so, confers colon cancer immune escape.

Citation Format: Chunwan Lu, Dafeng Yang, John D. Klement, II Kyu Oh, Natasha M. Savage, Jennifer L. Waller, Aaron H. Colby, Mark W. Grinstaff, Nicholas H. Oberlies, Cedric Pearce, Zhiliang Xie, Samuel Kulp, Christopher Coss, Mitch A. Phelps, Thomas Albers, Iryna O. Lebedyeva, Kebin Liu. The SUV39H1-H3K9me3 pathway represses cytotoxic T lymphocyte effector expression to confer colon carcinoma immune escape [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A32.
Abstract A33: The next-generation BET inhibitor, PLX51107, delays melanoma growth, altering the tumor immune microenvironment via Cox2 inhibition
Authors: Erkes Dan A. , Field Conroy O. , Capparelli Claudia , Tiago Manoela , Purwin Timothy J. , Heilman Shea A. , Chervoneva Inna , Berger Adam C. , Rosenbaum Sheera R. , Hartsough Edward J. , Villanueva Jessie , Aplin Andrew E.
Published: June 2021

Epigenetic agents such as bromodomain and extra terminal domain inhibitors (BETi) slow tumor growth via tumor intrinsic alterations; however, their effects on antitumor immunity remain unclear. A recent advance is the development of next-generation BETi that are potent and display a favorable half-life. Here, we tested the next-generation BETi, PLX51107, for immune-based effects on tumor growth in BRAF V600E melanoma syngeneic models. PLX51107 delayed melanoma tumor growth to differing degrees and altered the immunogenicity by lowering PD-L1 and FasL and increasing MHC-I in highly responsive melanomas. Moreover, PLX51107 treatment increased activated, proliferating and functional CD8+ T cells in tumors, leading to CD8+ T-mediated tumor growth delay. PLX51107 led to increased CD8-promoting, antitumor dendritic cells by acting as a Cox2 inhibitor. The accumulation of CSF-1R+ tumor-associated macrophages in poorly responsive melanoma limited PLX51107 efficacy. Importantly, PLX51107 delayed the growth of tumors that progressed on anti-PD-1 therapy, a response associated with decreased Cox2 levels, decreased PD-L1 expression and increased MHC-I expression on nonhematopoietic cells and increased intratumoral CD8+ T cells. Thus, next-generation BETi represent a potential first-line and secondary treatment strategy for metastatic melanoma by eliciting effects, at least in part, on antitumor immunity.

Citation Format: Dan A. Erkes, Conroy O. Field, Claudia Capparelli, Manoela Tiago, Timothy J. Purwin, Shea A. Heilman, Inna Chervoneva, Adam C. Berger, Sheera R. Rosenbaum, Edward J. Hartsough, Jessie Villanueva, Andrew E. Aplin. The next-generation BET inhibitor, PLX51107, delays melanoma growth, altering the tumor immune microenvironment via Cox2 inhibition [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A33.
Abstract A36: CXCL14-mediated antigen-specific CD8+ T-cell responses suppress HPV-positive head and neck cancer
Authors: Westrich Joseph A. , Vermeer Daniel W. , Bonney Stephanie , Silva Alexa , Berger Jennifer N. , Madeo Marianna , Cicchini Louis , Lee John H. , Spanos William C. , Pyeon Dohun
Published: June 2021

Human papillomaviruses (HPVs) cause over 5% of all human cancer incidences, including a subset of head and neck squamous cell carcinoma (HNSCC), resulting in about half a million deaths every year. Persistent infection with high-risk HPV is necessary for development of HPV-associated malignancies. To establish persistence in the host, HPV must evade host antiviral defenses, including the innate and adaptive immune responses. As antiviral and antitumor immune responses share similar mechanisms, it is likely that HPV-induced immune suppression leads to immune evasion and survival of HPV-infected cancer cells. We have previously shown that expression of the chemokine CXCL14 is significantly downregulated by promoter methylation mediated by the HPV oncoprotein E7 during cancer progression. Restoration of CXCL14 expression in HPV-positive HNSCC cells dramatically suppresses tumor growth through an immune-dependent mechanism in mice. While CXCL14 recruits NK and CD8+ T cells to the tumor microenvironment, the roles of NK and T cells to enact the CXCL14-mediated tumor suppression remained undefined. To determine the roles of NK and CD8+ T cells, tumor growth was assessed in wild-type C57BL/6 mice depleted of NK or CD8+ T cells and CD8-knockout mice injected with the HPV-positive HNSCC cells re-expressing CXCL14. The results show that that CD8+ T cells are required for CXCL14-mediated tumor suppression. The antitumor CD8+ T-cell responses require antigen specificity as a transgenic model of mice with a restricted CD8+ T-cell receptor failed to control tumor growth. Counteracting the HPV-mediated downregulation of major histocompatibility complex class I (MHC-I), CXCL14 expression restores MHC-I expression on HPV-positive HNSCC cells. Furthermore, knockdown of MHC-I expression in CXCL14 expressing HNSCC cells results in loss of tumor suppression, defining a critical role for antigen presentation. These results suggest that CXCL14 expression drives antigen-specific CD8+ T-cell responses and suppresses tumor growth through the restoration of MHC-I expression in HPV-positive HNSCC. Our findings provide useful insight into the CXCL14-mediated antitumor mechanism that increases CD8+ T-cell recognition of tumor cells and could boost the efficacy of current immunotherapies.

Citation Format: Joseph A. Westrich, Daniel W. Vermeer, Stephanie Bonney, Alexa Silva, Jennifer N. Berger, Marianna Madeo, Louis Cicchini, John H. Lee, William C. Spanos, Dohun Pyeon. CXCL14-mediated antigen-specific CD8+ T-cell responses suppress HPV-positive head and neck cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A36.
Abstract A50: Interleukin-33 increases ST2+ regulatory T cells and promotes metastatic tumor growth in the lungs in an amphiregulin-dependent manner
Authors: Halvorsen Elizabeth C. , Franks S. Elizabeth , Wadsworth Brennan J. , Harbourne Bryant T. , Cederberg Rachel A. , Steer Catherine A. , Martinez-Gonzalez Itziar , Calder Jack , Lockwood William W. , Bennewith Kevin L.
Published: June 2021

Regulatory T cells (Tregs) can facilitate primary and metastatic tumor growth through the suppression of antitumor immunity. Emerging evidence suggests a distinct role for Tregs in tissue repair and tissue barrier integrity by IL-33 mediated activation of the IL-33 receptor (ST2), causing the production of the epidermal growth factor receptor (EGFR) ligand amphiregulin (AREG). Treg-derived AREG is critical for the repair of infection-induced damage in the lungs, and AREG may induce tumor cell proliferation, invasion, migration or resistance to apoptosis by signaling through EGFR. We have previously shown that immune-suppressive myeloid-derived suppressor cells (MDSCs), macrophages, and Tregs are recruited to the lungs of mice bearing metastatic mammary tumors and promote metastatic growth in the lungs. We now show that IL-33 is dramatically increased in and around metastatic tumor foci in the lungs of mice bearing metastatic murine mammary tumors. We have also found that the majority of Tregs in the lungs of metastatic tumor-bearing mice express ST2, that Tregs express significantly more ST2 than conventional T cells, and that ST2+ Tregs produce significantly more AREG than ST2- Tregs. The intranasal administration of recombinant IL-33 increased the proportion of AREG producing ST2+ Tregs and enhanced the level of phosphorylated EGFR (pEGFR) in the metastatic lungs. While recombinant AREG did not impact the proliferation of mammary tumor cells in vitro despite inducing a dose-dependent increase in pEGFR, intranasal administration of recombinant AREG resulted in a ten-fold increase in pulmonary metastatic tumor burden in vivo. Further, the intranasal administration of recombinant IL-33 significantly increased metastatic tumor burden in the lungs in an AREG-dependent manner. These data identify ST2+ Tregs as a microenvironmental source of AREG in the lungs of metastatic mammary tumor-bearing mice and show that inhibition of AREG can reduce IL33-mediated increases in metastatic tumor growth. Our findings highlight an important role for IL33 and AREG in promoting metastatic growth and support the development of therapeutic strategies to inhibit AREG to reduce tumor metastases in the lungs.

Citation Format: Elizabeth C. Halvorsen, S. Elizabeth Franks, Brennan J. Wadsworth, Bryant T. Harbourne, Rachel A. Cederberg, Catherine A. Steer, Itziar Martinez-Gonzalez, Jack Calder, William W. Lockwood, Kevin L. Bennewith. Interleukin-33 increases ST2+ regulatory T cells and promotes metastatic tumor growth in the lungs in an amphiregulin-dependent manner [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A50.