Mouse Model Of Ovarian Cancer Research Articles

Intraperitoneal delivery of a neoantigen surrogate by Listeria monocytogenes in combination with checkpoint inhibition reduced tumor burden and improved survival in an ovarian cancer mouse model (2280)

Intraperitoneal delivery of a neoantigen surrogate by Listeria monocytogenes in combination with checkpoint inhibition reduced tumor burden and improved survival in an ovarian cancer mouse model (2280)

Single-cell transcriptomics identify TNFRSF1B as a novel T-cell exhaustion marker for ovarian cancer.

Ovarian cancer (OC) patients routinely show poor immunotherapeutic response due to the complex tumour microenvironment (TME). It is urgent to explore new immunotherapeutic markers. Through the single-cell RNA sequencing (scRNA-seq) analyses on high-grade serous OC (HGSOC), moderate severity borderline tumour and matched normal ovary, we identified a novel exhausted T cells subpopulation that related to poor prognosis in OC. Histological staining, multiple immunofluorescences, and flow cytometry were applied to validate some results from scRNA-seq. Furthermore, a tumour-bearing mice model was constructed to investigate the effects of TNFRSF1B treatment on tumour growth in vivo. Highly immunosuppressive TME in HGSOC is displayed compared to moderate severity borderline tumour and matched normal ovary. Subsequently, a novel exhausted subpopulation of CD8+ TNFRSF1B+ T cells is identified, which is associated with poor survival. In vitro experiments demonstrate that TNFRSF1B is specifically upregulated on activated CD8+ T cells and suppressed interferon-γ secretion. The expression of TNFRSF1B on CD8+ T cells is closely related to OC clinical malignancy and is a marker of poor prognosis through 140 OC patients' verification. In addition, the blockade of TNFRSF1B inhibits tumour growth via profoundly remodeling the immune microenvironment in the OC mouse model. Our transcriptomic results analyzed by scRNA-seq delineate a high-resolution snapshot of the entire tumour ecosystem of OC TME. The major applications of our findings were an exhausted subpopulation of CD8+ TNFRSF1B+ T cells for predicting OC patient prognosis and the potential therapeutic value of TNFRSF1B. These findings demonstrated the clinical value of TNFRSF1B as a potential immunotherapy target and extended our understanding of factors contributing to immunotherapy failure in OC.

Inhibition of CDK1 by RO-3306 Exhibits Anti-Tumorigenic Effects in Ovarian Cancer Cells and a Transgenic Mouse Model of Ovarian Cancer.

Ovarian cancer is the deadliest gynecological malignancy of the reproductive organs in the United States. Cyclin-dependent kinase 1 (CDK1) is an important cell cycle regulatory protein that specifically controls the G2/M phase transition of the cell cycle. RO-3306 is a selective, ATP-competitive, and cell-permeable CDK1 inhibitor that shows potent anti-tumor activity in multiple pre-clinical models. In this study, we investigated the effect of CDK1 expression on the prognosis of patients with ovarian cancer and the anti-tumorigenic effect of RO-3306 in both ovarian cancer cell lines and a genetically engineered mouse model of high-grade serous ovarian cancer (KpB model). In 147 patients with epithelial ovarian cancer, the overexpression of CDK1 was significantly associated with poor prognosis compared with a low expression group. RO-3306 significantly inhibited cellular proliferation, induced apoptosis, caused cellular stress, and reduced cell migration. The treatment of KpB mice with RO-3306 for four weeks showed a significant decrease in tumor weight under obese and lean conditions without obvious side effects. Overall, our results demonstrate that the inhibition of CDK1 activity by RO-3306 effectively reduces cell proliferation and tumor growth, providing biological evidence for future clinical trials of CDK1 inhibitors in ovarian cancer.

Effect of multi-targeting bacterial gene therapy on tumour regression and survival in mouse models of ovarian and intraperitoneal cancer.

e17550 Background: With a prevalence of more than 2 million cases, a 5-year survival below 20% in stage 3 and 4, and limited treatment options, ovarian cancer represents a significant unmet medical need. We assessed the efficacy of AUP-55, a genetically engineered Lactococcus cremoris for the treatment of ovarian cancer and peritoneal carcinomatosis. We evaluated the efficacy of two AUP-55 leads producing human therapeutic proteins in situ; namely interleukin 18 (IL-18), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-12 (IL-12) and interferon alpha (IFN-A) in syngeneic intraperitoneal ID8 ovarian cancer and B16F1 melanoma models in mice. Methods: ID8-Luc-mCherry-Puro ovarian cancer model was used for survival and tumor burden by bioluminescent imaging with post-mortem pathology for all animals, whereas the B16F1 melanoma model was used solely for survival. Animals were treated daily or every other day with i.p injections of the AUP-55 leads (1e8 CFU/dose for 12-22 times). Results: In the ID8 model treatment was started 14 days after tumor implantation. Most untreated mice were terminated due to the disease progress. Treatment with AUP-55 resulted in 91.3 % survival and lower tumor load during the study duration of 81 days compared to the 0 % survival and massively increased tumor load in untreated mice. When compared to the available data from the CRO, the survival advantage was superior to, for example anti-PD1 and cisplatin treatments in the same model. In the B16F1 model, treatment with AUP-55 led to 90 % survival in comparison to 10 % untreated mice. All AUP-55 treatments were well tolerated. In the pathology post-mortem, all untreated animals had typical findings for ovarian cancer, such as ascites and high number of tumor nodules present in abdominal cavity, liver, spleen, kidney and pancreas. In the group treated with AUP-55 there were no macroscopic tumor deposits detected. Conclusions: Cytokine armed Lactococcus cremoris AUP-55 enables multimodal action. Treatment with AUP-55 suggests anti-tumor activity as a single therapeutic entity for the treatment of ovarian cancer and peritoneal carcinomatosis.

Machine Learning Reveals Lipidome Remodeling Dynamics in a Mouse Model of Ovarian Cancer.

Ovarian cancer (OC) is one of the deadliest cancers affecting the female reproductive system. It may present little or no symptoms at the early stages and typically unspecific symptoms at later stages. High-grade serous ovarian cancer (HGSC) is the subtype responsible for most ovarian cancer deaths. However, very little is known about the metabolic course of this disease, particularly in its early stages. In this longitudinal study, we examined the temporal course of serum lipidome changes using a robust HGSC mouse model and machine learning data analysis. Early progression of HGSC was marked by increased levels of phosphatidylcholines and phosphatidylethanolamines. In contrast, later stages featured more diverse lipid alterations, including fatty acids and their derivatives, triglycerides, ceramides, hexosylceramides, sphingomyelins, lysophosphatidylcholines, and phosphatidylinositols. These alterations underscored unique perturbations in cell membrane stability, proliferation, and survival during cancer development and progression, offering potential targets for early detection and prognosis of human ovarian cancer.

Enhancement of sonodynamic treatment of ovarian cancer based on Pt-B-P ternary nanoparticles

Sonodynamic therapy (SDT) can noninvasively focus sound energy to deep tumor tissues and activate sonosensitizer (such as chlorin e6(Ce6)) to produce antitumor effects. However, due to the hypoxic microenvironment of the tumor, the effect of sonodynamic therapy is limited. In this work, we successfully synthesized Platinum-Boron-Phosphorus ternary nanoparticles (Pt-B-P NPs) for the first time to efficiently catalyze the decomposition of hydrogen peroxide (H2O2) in tumor tissues to produce sufficient oxygen (O2) and improve the effect of sonodynamic treatment of ovarian cancer. In vitro studies, we found that compared with Platinum nanoparticles (Pt NPs), Pt-B-P NPs have the significantly increased ability to catalyze the decomposition of H2O2 to produce oxygen and thus the hypoxic environment of tumor cells could be improved efficiently. Meanwhile, the bio-distribution, therapeutic effect and bio-safety of Pt-B-P NPs in vivo were evaluated using BALB/c-nu mouse model of ovarian cancer and the desired result had been achieved.

Combination ATR (ceralasertib) and PARP (olaparib) Inhibitor (CAPRI) trial in acquired PARP-inhibitor-resistant homologous recombination deficient ovarian cancer.

Addition of ataxia telangiectasia and Rad3-related kinase inhibitors (ATRi) to poly-ADP ribose polymerase inhibitors (PARPi) overcomes PARPi-resistance in high grade serous ovarian cancer (HGSOC) cell and mouse models. We present the results of an investigator-initiated study of combination PARPi(olaparib) and ATRi(ceralasertib) in patients with acquired PARPi-resistant HGSOC. Eligible patients had recurrent, platinum-sensitive BRCA1/2 mutated or homologous recombination (HR) deficient HGSOC and clinically benefited from PARPi (response by imaging/CA-125 or duration of maintenance therapy; >12 months 1st-line or >6 months ≥2nd-line) before progression. No intervening chemotherapy was permitted. Patients received olaparib 300mg twice daily and ceralasertib 160mg daily on days 1-7 of a 28-day cycle. Primary objectives were safety and objective response rate (ORR). Thirteen patients enrolled were evaluable for safety and 12 for efficacy. 62%(n=8) had germline BRCA1/2 mutations, 23% (n=3) somatic BRCA1/2 mutations, and 15%(n=2) HR-deficient tumors. Prior PARPi indication was treatment for recurrence (54%, n=7), 2nd line-maintenance (38%, n=5), and frontline treatment with carboplatin/paclitaxel (8%, n=1). There were 6 partial responses yielding an ORR of 50% (95% CI:0.15, 0.72). Median treatment duration was 8 cycles (range 4-23+). Grade(G) 3/4 toxicities were 38%(n=5); 15%(n=2) G3 anemia, 23%(n=3) G3 thrombocytopenia, 8% (n=1) G4 neutropenia. Four patients required dose-reductions. No patient discontinued treatment due to toxicity. Combination olaparib and ceralasertib is tolerable and shows activity in HR-deficient platinum-sensitive recurrent HGSOC that benefited and then progressed with PARPi as the penultimate regimen. These data suggest that ceralasertib re-sensitizes PARPi resistant HGSOCs to olaparib, warranting further investigation.

Establishment of highly metastatic ovarian cancer model with omental tropism via in vivo selection

Epithelial ovarian cancer (OC) is often diagnosed at an advanced stage with peritoneal metastasis, and preclinical models mimicking the natural course of OC peritoneal metastasis are essential to improve treatment. We implanted ES2 and ID8 cells in the ovaries of mice and obtained highly metastatic (HM) sublines from their omental metastases after three cycles invivo selection. Orthotopic xenografts derived from the HM sublines showed enhanced omental tropism and more extensive metastasis with earlier onset. The HM cells exhibited increased invitro migration and invasion properties, and RNA sequencing revealed that the genes related to epithelial-mesenchymal transition and extracellular matrix regulation were significantly altered in the HM cells. Among them, the upregulated genes were significantly associated with poorer survival in OC patients. In conclusion, these HM sublines can be leveraged to establish spontaneous metastatic OC mouse models, which may serve as ideal preclinical models for anti-metastasis therapy for OC patients.

Abstract 49: Comparison of subcutaneous and orthotopic tumor growth in syngeneic mouse models of ovarian and renal cancer

Abstract Oncology drug development has markedly lower success rate (3.4%) than other indications (20.9%) as reported by Wong, Siah and Lo in 2019. Animal models are often pointed at as the culprits for failure in clinical trials. While better animal models for cancer are needed and constantly developed, the incentive of drug developers to use those might not be clear, because the regulatory authorities do not require it. Subcutaneous tumors have earned their place in drug development but adding more sophisticated models to the testing panel before entering the clinical phase should improve the success rate. We present here the properties of subcutaneous and orthotopic tumor growth in two syngeneic models. HM-1 murine ovarian cancer cells were inoculated subcutaneously (s.c.) and intraperitoneally (representing the stage of intraperitoneal carcinomatosis) and murine renal adenocarcinoma Renca cells s.c. and orthotopically within the renal capsule. Body weight and tumor growth were followed, and mice were sacrificed according to humane endpoint criteria. To compare tumor growth in s.c. sites and within the abdomen, the tumor weight at sacrifice was divided by the number of days since the inoculation. In the HM-1 model, the mice with intraperitoneal tumor were sacrificed due to build-up of ascites on average six days earlier that the mice with s.c. tumor. In s.c. HM-1 tumor-bearing mice, the reason for sacrifice was tumor ulceration. In the Renca model, the s.c. and intrabursal models were approximately the same length. There was a striking difference in the tumor growth rate (mg/day) in s.c. versus abdominal sites in both models. The growth was 4-5 times faster in the abdominal sites than subcutaneously, highlighting the effect of tumor specific microenvironment. It is easy to understand that having promising results might be easier in a slower growing model. However, since both ovarian and renal cancer show very different growth kinetics within the abdominal cavity, testing drug candidates aimed for those indications in orthotopic models before accessing the clinical trials could give a more relevant evaluation of the potency of the drug candidates. Citation Format: Mari I. Suominen, Justyna Zdrojewska, Yvonne Konkol, Katja M. Fagerlund, Mervi Ristola, Jukka P. Rissanen. Comparison of subcutaneous and orthotopic tumor growth in syngeneic mouse models of ovarian and renal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 49.

Abstract 1772: Development of a novel L1CAM-targeted CAR-T, CX804, and its therapeutic efficacy in ovarian and gastric cancer

Abstract L1 cell adhesion molecule (L1CAM) is involved in cancer development and aberrantly expressed in various tumor. It is also associated with aggressive progression, metastasis, and poor prognosis. Public database, a Kaplan-Meier plotter (http://www.kmplot.com) shows that L1CAM high-expression significantly reduced survival of ovarian and gastric cancer patients. We developed a novel chimeric antigen receptor (CAR)-T cell targeted to L1CAM. A novel scFV candidate (Clone H8) to L1CAM was obtained by bio-panning of phage displaying human synthetic scFv fragments to human and mouse L1CAM proteins. H8 scFV was linked to IgD-IgG1 hinge, CD28 transmembrane domain, CD28 and ICOS co-stimulation domain, and CD3ζ domain, resulting in CX804 CAR-T. The efficacy of L1CAM CAR-T cells, CX804 showed correlation with the level of L1CAM in human ovarian and gastric cancer cells. CX804 exerted cytotoxicity toward 293T cells expressing human or mouse L1CAM protein. CX804 also reacted with L1CAM-positive ovarian SKOV3 cancer cell and gastric MKN-28 and AGS cancer cells and secreted T-cell activation cytokines, IFN-γ and TNF-α, in response to these cells. However, CX804 rarely lysed L1CAM-negative normal 293 cells and SNU-719 gastric cancer cells. Furthermore, L1CAM CAR-T cells dramatically lysed high L1CAM expressing patient derived cell (PDC) of gastric cancer compared with low L1CAM expressing PDC cell. Xenograft model of ovarian cancer was developed by intraperitoneal (IP) injecting SKOV3-Fluc cells into NOD/SCID or NSG mice. CAR-T cells were administrated via intravenous (IV) or IP route on 5 days after tumor inoculation. Administration of CX804 significantly decreased tumor burden and increased survival in mouse model of ovarian cancer. Route of administration significantly affected bio-distribution and antitumor effect of CX804 where antitumor activity of CX804 was only observed when CX804 were given IP, but not the IV route. Taken together, our results suggest that CX804 exerts potent and specific effect against L1CAM positive cancer cells in vitro and in vivo. Furthermore, we propose that newly established CAR-T cells targeting L1CAM facilitate therapy against L1CAM-positive ovarian and gastric cancer patients Citation Format: Xiumei Che, Un-Jung Yun, Seokwon Lee, Youngyoub Kim, Junshub Lee, Jina Chae, Jehee Suh, Eun-Ji Nam, Gun Min Kim, Hyoyoung Kim, Minkyu Jung. Development of a novel L1CAM-targeted CAR-T, CX804, and its therapeutic efficacy in ovarian and gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1772.

Abstract 2739: Genetic modification of mesothelial cells with full length membrane-bound TRAIL for ovarian cancer treatment

Abstract Mesothelial cells lining the peritoneum play an important role in epithelial ovarian cancer (EOC) locoregional spreading by promoting cancer cell proliferation, adhesion, and invasion into the peritoneal wall and organs. Peritoneal dissemination represents a critical first step in EOC progression, and we posit that genetic modification of mesothelial cells with full length membrane-bound TRAIL is a practical approach to intervention and will provide local control of EOC progression. Here, we stably overexpressed full length tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with a lentiviral vector in the immortalized mesothelial cell line, MeT5A. Overexpression of TRAIL on the cell surface of MeT5A was confirmed by flow cytometry, and no obvious changes in proliferation or morphology were observed when MeT5A/TRAIL cells were grown in culture. In co-culture experiments, however, MeT5A/TRAIL cells induced apoptosis of surrounding cancer cells and continued proliferating until the culture surface was confluent with mesothelial cells alone. Interestingly, MeT5A/TRAIL not only induced cell death of TRAIL-sensitive cancer cells, such as OVCAR3 and H460, but it also induced significant apoptosis of cancer cells previously deemed resistant to soluble TRAIL, such as A2780, and OVCAR8. This finding suggests that full length TRAIL (amino acid 1-281) expressed on the cell surface is capable of activating death receptor-mediated apoptotic pathways that are not reactive to the soluble form of TRAIL (amino acid 114-281), which was previously developed as a cancer therapeutic and thoroughly evaluated in animal models and clinical trials. When co-cultured with MeT5A/TRAIL, primary ovarian cancer cells from patients also underwent apoptosis as detected by flow cytometry and the upregulation of cleaved caspase-3, caspase-8, caspase-9, PARP, and Bid on Western blots. Next, we assessed the anticancer potential of mesothelial cells expressing membrane-bound TRAIL in a NSG xenograft mouse model of ovarian cancer. Intraperitoneal inoculation of MeT5A/TRAIL cells significantly reduced overall cancer burden in mice where OVCAR3, A2780, and OVCAR8 cancer cells were pre-established. Intraperitoneal gene delivery of TRAIL to resident peritoneal mesothelial cells utilizing a conditionally replicative adenovirus vector also prolonged survival of NSG mice bearing A2780 xenografts. Our data suggest that genetic modification of mesothelial cells with full length membrane-bound TRAIL is feasible and has therapeutic potential for disrupting EOC progression. Citation Format: Er Yue, Tonya Walser, Tamara Mirzapoiazova, Ravi Salgia, Edward W. Wang. Genetic modification of mesothelial cells with full length membrane-bound TRAIL for ovarian cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2739.

Abstract 4248: Epithelial ovarian cancer causes cardiac dysfunction and myofilament dysregulation

Abstract Introduction: The intersections between cancer and cardiovascular disease (CVD) have become increasingly relevant in the care of both patient populations. To date, the cardio-oncology field has largely focused on how cancer treatment influences long-term cardiac health. Indeed, many cancer therapeutics show various toxic effects to the cardiovascular system. However, studies have also shown cardiac deficits in therapy-naïve cancer patients. This suggests that these two disease states interact through similar signaling pathways, yet the mechanisms underlying cancer-induced cardiac dysfunction remain unknown. Thus, we investigated cardiac structure and function throughout the progression of epithelial ovarian cancer (EOC). Methods: We used an orthotopic, syngeneic mouse model of ovarian cancer. Briefly, transformed murine ovarian surface epithelial cells from C57BL/6 mice (ID8; 1.0 × 106), or saline for surgical controls, were injected under the ovarian bursa of syngeneic mice. In this model, 60 days after tumor induction, mice form large ovarian masses, numerous peritoneal lesions, and develop abdominal ascites - consistent with the clinical features of stage III (advanced) EOC. To determine whether cardiac abnormalities precede the presence of advanced disease, at 45 days post-tumor induction, mice were anesthetized, and left ventricular (LV) structure and function were assessed by echocardiography and invasive hemodynamics, respectively. Myofilament activity was measured with an actomyosin MgATPase assay and protein phosphorylation was determined by SDS-PAGE with Pro-Q Diamond phosphoprotein staining. Results: EOC mice showed systolic (i.e., reduced contraction rate) and diastolic dysfunction (i.e., reduced relaxation rate, elevated diastolic filling pressure), with no evidence of hypertrophy or atrophy (i.e., no change in LV wall thickness or dimension). While there were no observed differences in myofilament ATPase activity, phosphorylation of regulatory myosin light chain 2 (MYL2) and cardiac myosin binding protein C (cMyBP-C) decreased, and tropomyosin (Tpm) phosphorylation increased in EOC mice. Conclusion: Together, these data demonstrate that ovarian cancer impairs cardiac function and alters the regulation of myofilament proteins critical for contraction and relaxation. Interestingly, the observed dephosphorylation of MYL2 and cMyBP-C and hyperphosphorylation of Tpm are consistent with features of heart failure. The findings build upon our current understanding of the interactions between cancer and CVD and show that deficits in the heart precede the development of advanced malignancy. Future work further will investigate the tumor-heart axis to identify how tumor development disrupts normal cardiac physiology. Citation Format: Leslie M. Ogilvie, Madison Pereira, Kathy Matuszewska, Bridget Coyle-Asbil, Luca J. Delfinis, Shivam Gandhi, Keith R. Brunt, Christopher G. Perry, W. Glen Pyle, Jim Petrik, Jeremy A. Simpson. Epithelial ovarian cancer causes cardiac dysfunction and myofilament dysregulation. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4248.

Abstract 5556: Lemur tyrosine kinase 3 serves as a predictor of patient outcome and a target for the treatment of ovarian cancer

Abstract The objective of these in vitro and in vivo studies was to validate Lemur Tyrosine Kinase 3 (LMTK3) as a specific target and predictor of clinical outcome in ovarian cancer. LMTK3 belongs to a family of regulated tyrosine kinases with three structurally related isoforms, LMTK1, LMTK2, and LMTK3. Both nuclear and cytoplasmic LMTK3 expressions correlated with tumor grade and patient survival in cancers such as breast and colorectal cancer. We tested the clinical significance of the LMTK3 gene by immunohistochemistry (IHC) using LMTK3 monoclonal antibody on formalin-fixed paraffin-embedded sections (FFPE) collected from 204 early-stage (stage I-II) ovarian cancer patients. Results from this IHC LMTK3 study revealed a higher cytoplasmic to nuclear localization of LMTK3 correlated with worse overall survival (P<0.01). Further investigation of LMTK3’s prognostic value by screening LMTK3 signaling in 270 stage III-IV ovarian cancer patients is ongoing. We utilized the MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay for testing the killing efficacy of targeting LMTK3 by a monoclonal antibody, siRNA, and specific LMTK3 binding peptides (LMTK3BP) in ovarian cancer cell lines SKOV3, MDAH-2774, A2780, and TOV-21G. Treatment with LMTK3 specific monoclonal antibody, siRNA, and LMTK3BP significantly induced killing of both chemosensitive and chemoresistant ovarian cancer cells without affecting normal cells in vitro. Moreover, we observed this killing as synergistic with both Cisplatin and Taxotere treatment in vitro. Lastly, we used an A2780 cell line derived orthotopic xenograft mouse model of ovarian cancer to test the efficacy of specific LMTK3BP in vivo. Strikingly, LMTK3BP 20 mg/kg IV dose given three times a week for three weeks showed a 35% tumor reduction. Furthermore, in vivo safety studies showed no signs of toxicity of the LMTK3BP, even at a very high dose of 40 mg/kg. Thus, with dose optimization in ongoing experiments, we could expect a higher efficacy. In conclusion, this study highlighted the importance of LMTK3 as a predictor of patient clinical outcome and potential target for treatment in ovarian cancer. Citation Format: Thea K. Kirsch-Mangu, Axel S. Tullberg, Anna Portela, Khalil Helou, Ghassan M. Saed. Lemur tyrosine kinase 3 serves as a predictor of patient outcome and a target for the treatment of ovarian cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5556.

Abstract 4455: Protein phosphatase 4 inhibition stimulates anti-tumor immunity in ovarian cancer

Abstract Background: Increased infiltration of T cells into ovarian tumors has been repeatedly shown to be predictive of enhanced patient survival. However, despite the evidence of an active immune response in OC, immune checkpoint blockade therapy has been ineffective. Recently studies have shown that deficiencies in the DNA damage response (DDR) can drive increased genomic instability and tumor immunogenicity. One target involved in the DDR that has the potential to be of therapeutic value is protein phosphatase 4 (PP4); however, the effect of PP4 deficiency on anti-tumor immunity remain unknown. Results: Our results show that PP4 inhibition combined with carboplatin leads to increased carboplatin sensitivity, DNA damage, and micronuclei formation. Using a panel of ovarian cancer cells, we show that PP4 inhibition triggers inflammatory signaling via NF-κB and STAT1 activation resulting in increased expression of pro-inflammatory cytokines including IFNβ1, CCL5, CXCL10, and IL-6. Moreover, conditioned media from OC cells treated with the combination of PP4 inhibitor and carboplatin significantly increased migration of both CD8 T cell and NK cells over carboplatin treatment alone. Knockdown of STING in OC cells significantly abrogated the increase in CD8 T cell migration induced by PP4 inhibition. PPP4C or PPP4R3B knockdown resulted in strong induction of NK cell IFN-γ, increased degranulation, and increased NK cell-mediated cytotoxicity against OC cells. Stable knockdown of PP4C in a syngeneic, immunocompetent mouse model of ovarian cancer resulted in significant reduction of tumor growth in vivo. PP4C low tumors had increased infiltration of CD161+ NK cells and CD4+ T cells. Addition of low dose carboplatin treatment in vivo led to increased CD8+ T cell infiltration in PP4C low tumors when compared to the untreated groups. Conclusions: Our work has identified a role for PP4 inhibition in promoting anti-tumor immune activation. These findings provide the rationale for combining PP4 inhibitors with immunotherapy as a new approach in ovarian cancer treatment. Citation Format: Remya Raja, Christopher Wu, Esen Y. Bassoy, Thomas Rubino, Emma Utagawa, Paul Magtibay, Kristina Butler, Marion Curtis. Protein phosphatase 4 inhibition stimulates anti-tumor immunity in ovarian cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4455.

Abstract 354: The progression of changes in cardiac structure and function in mice with epithelial ovarian cancer

Abstract Introduction: Cancer cachexia, characterized by the progressive loss of muscle mass (i.e., atrophy), has a significant impact on patient prognosis and quality of life. While skeletal muscle atrophy and weakness are well characterized in cancer patients, the progression of cancer-induced cardiac atrophy has received little attention. Preliminary work from our lab has shown that cardiac dysfunction, measured by invasive hemodynamic assessment, precedes the development of metastatic disease in a mouse model of epithelial ovarian cancer (EOC). Yet, the time course of changes in cardiac structure and function throughout the progression of ovarian cancer remain unknown. Thus, we non-invasively assessed changes in cardiac structure and function through the progression of EOC. Methods: To investigate the impact of advanced ovarian cancer on cardiac structure and function, we used an orthotopic, syngeneic mouse model of EOC. This model was generated by injecting transformed murine ovarian surface epithelial cells (ID8; 1.0 × 106) or saline (surgical sham) directly under the ovarian bursa of syngeneic mice. Echocardiography was used to assess changes in cardiac structure and function throughout the progression of EOC at days 45, 60, 75, and 90 post-tumor induction (PTI). Morphometric assessments at each timepoint were used to determine the presence of cardiac atrophy. Results: Echocardiography showed that EOC mice had preserved left ventricular (LV) function (i.e., ejection fraction) with no change in structural dimensions at days 45, 60 and 75 PTI. By day 90 PTI, LV wall thickness and end-systolic dimension decreased, suggesting evidence of cardiac atrophy. Consistent with echocardiographic data, morphometric assessment showed profound atrophy at 90 days PTI, but preserved cardiac mass at all other timepoints compared to shams. Conclusion: Together, this work demonstrates that when non-invasive techniques are used to measure changes in cardiac structure, atrophy is not evident until advanced stage ovarian cancer (i.e., 90 days PTI). Despite this, preliminary work from our lab has shown that cardiac dysfunction is present in EOC mice by 45 days PTI when assessed by invasive hemodynamics. Although echocardiography is a widely used technique for measuring indices of cardiac structure and function, our work demonstrates it lacks sensitivity to detect cardiac deficits until the overt stages of disease that accompany cancer cachexia. Thus, it is important to consider that subclinical cardiac dysfunction may exist in the early stages of cancer progression, however, these changes may go undetected unless more sensitive hemodynamic assessments are employed. Citation Format: Bridget Coyle-Asbil, Leslie M. Ogilvie, Madison Pereira, Kathy Matuszewska, Luca J. Delfinis, Shivam Gandhi, Keith R. Brunt, Christopher G. Perry, Jim Petrik, Jeremy A. Simpson. The progression of changes in cardiac structure and function in mice with epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 354.

Abstract 370: Potential of inflammation pro-resolving lipid mediators in controlling cancer cachexia

Abstract Most people with advanced cancer exhibit cachexia, a syndrome of progressive weight loss that leads to the death of 20% of patients. The mechanisms underlying cachexia remain poorly understood and, as a result, no treatment has proven effective to date. Cachexia is characterized by systemic hyperinflammation, massive apoptotic cell death (“debris”), and skeletal muscle wasting. Here, we hypothesize that disrupted resolution of inflammation contributes to cancer cachexia, and pro-resolving lipid mediators, specifically novel specialized pro-resolving mediators (SPMs), could control cachexia. SPMs enhance resolution of inflammation by stimulating debris clearance, promoting tissue regeneration, and regulating major immune cell types. In testing our hypothesis, we profiled lipid mediators in a variety of metastatic cachexia models via metabololipidomics and investigated the changes of leukocytes, e.g., T lymphocyte, natural killer (NK), and macrophage cells, in various skeletal muscles (e.g., tibialis anterior and gastrocnemius). Dysregulation of SPMs was identified in different tissues in 5 cachexia models. The SPMs resolvin (RvD)2 and maresin (MaR)1 were reduced in the liver and spleen of colon cancer (CT26)-induced cachectic mice on day 35 post-tumor cell injection and RvD1, RvD2, lipoxin (LXA)4, and MaR1 were dysregulated in Lewis lung carcinoma (LLC)-induced cachectic mice on day 20. Chemotherapy was also found to dysregulate SPMs and induce cachexia in lymphoma (EL4) and ovarian cancer (ID8) mouse models. Ten days post-LLC tumor resection, the RvD1 receptor (ALX/FPR2) KO and RvE1 receptor (ChemR23/ERV) KO mice exhibited a 20-23% loss in body weight compared to WT mice. This shows that neutralizing the pro-resolving activity of RvD1 and RvE1 induces cancer cachexia. Moreover, RvD2 and PCTR (protectin conjugates in tissue regeneration)-2 prevented LLC- and B16F10 melanoma-induced cachexia at 15 ng/day. RvD4, RvD5, MCTR1, or MCTR2 inhibited inflammation-stimulated cytokine storm by counter-regulating the production of CCL3, CCL4, CXCL2, TNF-α, CCL2, G-CSF, and PAI-1. These results indicate that disrupted resolution of inflammation leads to the progression of cancer cachexia, and dysregulated SPMs are potential early markers for cachexia. This study provides a basis for the clinical translation of SPM-directed treatments as a new direction to potentially control cancer cachexia in humans. Citation Format: Ahmed Attaya, Victoria Haak, Abigail Kelly, Haixia Yang, Eva Rothenberger, Steven D. Freedman, Charles N. Serhan, Dipak Panigrahy. Potential of inflammation pro-resolving lipid mediators in controlling cancer cachexia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 370.

Abstract 6798: CD8α+ dendritic cells potentiate the antitumor and immune activities against murine ovarian cancers

Abstract Objectives: Dendritic cell (DC) based immunotherapies have been shown to be a potential treatment option for various cancers; however, the exact strategies in ovarian cancer remain unknown. This study aimed to evaluate the effectiveness of mouse CD8α+ dendritic cells (DCs), corresponding to human CD141+ DCs, derived from bone marrow (BM) hematopoietic stem cells (HSCs) in a syngeneic and orthotopic mouse ovarian cancer model. Methods: Stem-DCs from HSCs and Mono-DCs from monocytes were generated from the bone marrow mononuclear cells (BM-MNCs) of C57BL/6 mice in condition of pulsing with ID8 tumor cell lysates. C57BL/6 mice were intraperitoneally injected with 5 × 106 ID8 cells. They were treated with vehicle, low/medium/high dose pulsed Stem-DCs, Mono-DCs, and unpulsed Stem-DCs. At 8 to 9 weeks, the treated mice were sacrificed, and tumor responses and immune responses, such as lymphocyte proliferation and cytokine secretion, were analyzed. Results: Mono-DCs and Stem-DCs were characterized by CD11c+CD80+CD86+ and CD8α+Clec9a+ expression, respectively. They were confirmed by the secretion of immunostimulatory cytokines, such as interleukin (IL)-12 and interferon (IFN)-γ, and T cell proliferation was observed after maturation. Despite a lower dose compared with Mono-DCs, mice treated with pulsed Stem-DCs showed a reduced amount of ascitic fluid and lower body weights compared with those of vehicle treated mice (P = 0.0021 and P = 0.0092, respectively). These mice treated with pulsed Stem-DCs appeared to have fewer tumor implants which were usually confined in the epithelium of ovaries, diaphragm and peritoneum. All mice injected with DCs demonstrated longer survival than the vehicle group (P = 0.0187), especially the medium/high dose pulsed Stem-DC treatment groups. Moreover, these favorable tumor responses were associated with a low proportion of myeloid-derived suppressor cells (MDSCs) and regulatory T cells, high IL-12 and IFN-γ levels, and accumulation of several tumor-infiltrating lymphocytes. Conclusions: We demonstrated that mouse CD8α+ DCs derived from BM HSCs could decrease tumor progression and enhance antitumor immune responses against murine ovarian cancer. Further studies are necessary to develop potent DC vaccines using human CD141+ DCs. Citation Format: Shin-Wha Lee, Dasol Oh, Hyunah Lee, Kyung-Won Lee, Min-Je Kim, Sung Wan Kang, Young-Jae Lee, HyunSoo Kim, Yong-Man Kim. CD8α+ dendritic cells potentiate the antitumor and immune activities against murine ovarian cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6798.

Abstract 5957: Chemotherapy-induced extracellular matrix remodeling in HGSOC

Abstract In this study we explored the effects of chemotherapy on the extracellular matrix of high-grade serous ovarian cancer metastasis (HGSOC) at structural-textural protein level and transcriptionally, in order to identify the microenvironmental features that accompany a successful response. We studied two murine orthotopic, transplantable syngeneic models of HGSOC, one that displays excellent response to carboplatin/paclitaxel (60577) and one that is resistant to treatment (HGS2)1. Using immunohistochemistry, we stained omental tumors from both models for the ECM components fibronectin (FN1), collagen 1A1 (COL1A1) and versican (VCAN), also using Masson’s Trichrome to stain for collagen. We analyzed their abundance, textural features (Haralick features) and structure with the image analysis softwares, QuPath and TWOMBLI respectively. A compilation of 44 ECM metrics, which we named the “structure index”, correlated with response to chemotherapy, as measured by reduction in omental tumor weight. In parallel, we performed RNAseq on the omental tumors, identifying clusters of genes that change over time with chemotherapy treatment of the responsive model 60577, while the chemoresistant model HGS2 displayed limited alteration of gene expression. We integrated RNAseq and ECM structure and texture data, and showed the structure index was correlated with 144 core matrisome genes. To identify potential therapeutic targets, we then focused our study on genes that remained highly expressed in resistant tumors post chemotherapy, but were originally low or decreased with treatment in the sensitive tumors. Members of the LOX and P4HA family were found amongst these genes. We confirmed by immunohistochemical analysis that expression of LOX, LOXL2, P4HA1 and P4HA2 was downregulated by chemotherapy in the 60577 chemo-sensitive tumors while their levels remained relatively unaffected in the resistant HGS2 tumors. This study refines our understanding of the mechanisms of microenvironmental chemoresistance in HGSOC, highlighting putative therapeutic targets to increase the efficacy of platinum-based chemotherapy in ovarian cancer. 1 Maniati, E. et al. Mouse Ovarian Cancer Models Recapitulate the Human Tumor Microenvironment and Patient Response to Treatment. Cell Rep 30, 525-540.e527, doi:10.1016/j.celrep.2019.12.034 (2020). Citation Format: Panoraia Kotantaki, Florian Laforêts, Eleni Maniati, Chiara Berlato, Anna Malliouri, Michael John Devlin, Beatrice Malacrida, Samar Elorbany, Ranjit Manchanda, Frances R. Balkwill. Chemotherapy-induced extracellular matrix remodeling in HGSOC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5957.

An oncolytic herpes simplex virus type 1 strain expressing a single-chain variable region antibody fragment against PD-1 and a PI3K inhibitor synergize to elicit antitumor immunity in ovarian cancer

Due to recurrence and resistance to chemotherapy, the current standard therapeutics are not fully effective against ovarian cancer. Therefore, we aimed to find an effective approach to improve the prognosis and therapy of ovarian cancer. NG34ScFvPD-1 is a modified oncolytic herpes simplex virus NG34 strain that expresses a single-chain antibody against programmed cell death protein 1 (PD-1) (ScFvPD-1). We assessed its efficacy and its regulatory mechanism in a mouse model of ovarian cancer. Enzyme-linked immunosorbent assay and western blot techniques were used to measure protein expression. Oncolysis caused by NG34ScFvPD-1 was examined using cytotoxicity and replication assays. The mechanism by which NG34ScFvPD-1 regulates apoptosis of ovarian cancer cells in vitro was also evaluated. We assessed the antitumor immunity and therapeutic potency of NG34ScFvPD-1 in combination with a phosphoinositide 3-kinase (PI3K) inhibitor. We found that NG34ScFvPD-1-infected ovarian cancer cells expressed and secreted ScFvPD-1, which bound mouse PD-1. The insertion of the ScFvPD-1 sequence did not inhibit the oncolytic activity of NG34ScFvPD-1, which induced apoptosis of ovarian cancer cells via the caspase-dependent pathway in vitro and activated the PI3K/AKT signaling pathway. Synergy was observed between NG34ScFvPD-1 and a PI3K inhibitor, and the combination was able to suppress tumor development, to prolong survival, and to elicit potent antitumor immunity. Thus, inhibition of PI3K enhanced the potent antitumor immunity induced by NG34ScFvPD-1 against ovarian cancer.

Matrix Gla Protein drives stemness and tumor initiation in ovarian cancer

Ovarian cancer (OC) displays the highest mortality among gynecological tumors, mainly due to early peritoneal dissemination, the high frequency of tumor relapse following primary debulking, and the development of chemoresistance. All these events are thought to be initiated and sustained by a subpopulation of neoplastic cells, termed ovarian cancer stem cells (OCSC), that are endowed with self-renewing and tumor-initiating properties. This implies that interfering with OCSC function should offer novel therapeutic perspectives to defeat OC progression. To this aim, a better understanding of the molecular and functional makeup of OCSC in clinically relevant model systems is essential. We have profiled the transcriptome of OCSC vs. their bulk cell counterpart from a panel of patient-derived OC cell cultures. This revealed that Matrix Gla Protein (MGP), classically known as a calcification-preventing factor in cartilage and blood vessels, is markedly enriched in OCSC. Functional assays showed that MGP confers several stemness-associated traits to OC cells, including a transcriptional reprogramming. Patient-derived organotypic cultures pointed to the peritoneal microenvironment as a major inducer of MGP expression in OC cells. Furthermore, MGP was found to be necessary and sufficient for tumor initiation in OC mouse models, by shortening tumor latency and increasing dramatically the frequency of tumor-initiating cells. Mechanistically, MGP-driven OC stemness was mediated by the stimulation of Hedgehog signaling, in particular through the induction of the Hedgehog effector GLI1, thus highlighting a novel MGP/Hedgehog pathway axis in OCSC. Finally, MGP expression was found to correlate with poor prognosis in OC patients, and was increased in tumor tissue after chemotherapy, supporting the clinical relevance of our findings. Thus, MGP is a novel driver in OCSC pathophysiology, with a major role in stemness and in tumor initiation.