Immunotherapy Of Ovarian Cancer Research Articles

Ovarian Cancer Cells Promote Glycolysis Metabolism and TLR8-Mediated Metabolic Control of Human CD4+ T Cells.

An immunosuppressive microenvironment is a major obstacle for successful tumor immunotherapy. Elucidating the regulatory mechanisms of energy metabolism and functionality in CD4+ T cells will provide insights for the development of novel immunotherapies for ovarian cancer (OC). An Agilent microarray was used to detect differences in gene expression between peripheral CD4+ T cells from five OC patients and those from five healthy controls. Functional pathway analysis was performed for differentially expressed genes. Gene expression profiles revealed significant differences in expression levels of 5,175 genes in peripheral CD4+ T cells from five patients with OC. Functional analysis indicated that the most significantly enriched pathways were metabolic pathways. Furthermore, eight glycolysis-related genes all showed significantly increased expression in peripheral CD4+ T cells of OC patients. Moreover, we established a coculture system of human CD4+ T cells with the OC cell line SKOV3, and then treated them with toll-like receptor 8 (TLR8) ligand ssRNA 40. Coculturing with SKOV3 cells could increase the expression of the eight glycolysis-related genes, promote glucose uptake and glycolysis in CD4+ T cells, induce the differentiation of CD4+ CD25+ Foxp3+ T cells, and enhance the suppression of naïve CD4+ T cells. Additionally, activated TLR8 signaling could mediate the reprogramming of glycolysis metabolism and function in CD4+ T cells. Overall, our study indicates that the SKOV3 coculture environment could regulate the glycolysis metabolism and function of CD4+ T cells, and also that TLR8 mediated the metabolic control of glycolysis in CD4+ T cells cocultured with SKOV3 cells. This provides a new direction for immunotherapy investigations in OC.

Generated SecPen_NY-ESO-1_ubiquitin-pulsed dendritic cell cancer vaccine elicits stronger and specific T cell immune responses

Dendritic cell-based cancer vaccines (DC vaccines) have been proved efficient and safe in immunotherapy of various cancers, including melanoma, ovarian and prostate cancer. However, the clinical responses were not always satisfied. Here we proposed a novel strategy to prepare DC vaccines. In the present study, a fusion protein SNU containing a secretin-penetratin (SecPen) peptide, NY-ESO-1 and ubiquitin was designed and expressed. To establish the DC vaccine (DC-SNU), the mouse bone marrow-derived DCs (BMDCs) were isolated, pulsed with SNU and maturated with cytokine cocktail. Then peripheral blood mononuclear cells (PBMCs) from C57BL/6 mice inoculated intraperitoneally with DC-SNU were separated and cocultured with MC38/MC38NY-ESO-1 tumor cells or DC vaccines. The results show that SNU was successfully expressed. This strategy made NY-ESO-1 entering cytoplasm of BMDCs more efficiently and degraded mainly by proteasome. As we expected, mature BMDCs expressed higher CD40, CD80 and CD86 than immature BMDCs. Thus, the PBMCs released more IFN-γ and TNF-α when stimulated with DC-SNU in vitro again. What's more, the PBMCs induced stronger and specific cytotoxicity towards MC38NY-ESO-1 tumor cells. Given the above, it demonstrated that DC-SNU loaded with SecPen and ubiquitin-fused NY-ESO-1 could elicit stronger and specific T cell immune responses. This strategy can be used as a platform for DC vaccine preparation and applied to various cancers treatment.

Enhancing delivery of small molecule and cell-based therapies for ovarian cancer using advanced delivery strategies.

Ovarian cancer is the most lethal gynecological malignancy with a global five-year survival rate of 30-50%. First-line treatment involves cytoreductive surgery and administration of platinum-based small molecules and paclitaxel. These therapies were traditionally administered via intravenous infusion, although intraperitoneal delivery has also been investigated. Initial clinical trials of intraperitoneal administration for ovarian cancer indicated significant improvements in overall survival compared to intravenous delivery, but this result is not consistent across all studies performed. Recently cell-based immunotherapy has been of interest for ovarian cancer. Direct intraperitoneal delivery of cell-based immunotherapies might prompt local immunoregulatory mechanisms to act synergistically with the delivered immunotherapy. Based on this theory, pre-clinical in vivo studies have delivered these cell-based immunotherapies via the intraperitoneal route, with promising results. However, successful intraperitoneal delivery of cell-based immunotherapy and clinical adoption of this technique will depend on overcoming challenges of intraperitoneal delivery and finding the optimal combinations of dose, therapeutic and delivery route. We review the potential advantages and disadvantages of intraperitoneal delivery of cell-based immunotherapy for ovarian cancer and the pre-clinical and clinical work performed so far. Potential advanced delivery strategies, which might improve the efficacy and adoption of intraperitoneal delivery of therapy for ovarian cancer, are also outlined.

Abstract 3309: Cardioprotective paraoxonase 2 enhances the tumoricidal activity of natural killer cells in a paracrine manner

Abstract Background: Immune system can recognize the neoplastic cells and target them for destruction through tumoricidal process. Further, immune cell dysfunction leads to escape of cancer cells from immune recognition, lead to the initiation and progression of tumor formation. Clinical shreds of evidence suggest that the presence of intratumoral immune cells correlates with improved progression free and overall survival among patients with ovarian carcinoma and provide evidence of activation of antitumor mechanisms. Hence identification of drugs that target the cancer cells as well as activate the immune cells is a sound strategy for cancer therapy. Paraoxonase 2 (PON2) is a membrane-associated lactonase with lipid transport, anti-oxidant and phagocytosis/efferocytosis properties. PON2 deficiency aggravates systemic inflammation, and causes the metabolic associated diseases. Recently we have reported that overexpression of PON2 reduces the ovarian cells proliferation and tumor formation by reducing IGF-1 production and its signaling pathway. Further, using microarray based experiment, we have identified several pathways that modulate the immune cells function such as activation of Natural Killer (NK) cells, dendritic cell maturation, B cells activation, and communication between innate and an adaptive cells signaling pathway were regulated by PON2. Hypothesis: PON2 enhances tumoricidal activity in a paracrine fashion. Methods and Results: NK cells were isolated from control C57BL/6 and purity was assessed with flow cytometry using FITC anti mouse CD49B and results revealed that 95 % of NK cells population. NK cells treated with condition medium from ID8hPON2 (human PON2 overexpressed in mouse ovarian cancer cell line) show an increase in tumoricidal activity compared to condition medium from ID8EV. Neither ID8hPON2 nor ID8EV condition medium affects the viability of NK cells. Moreover, there is no difference in CD49B positive staining in the tumor microenvironment between ID8EV and ID8hPON2 cells receiving mice. Condition medium obtained from ID8hPON2 ID8EV group shows increases the interleukin 18 level and neutralizing antibody against IL18 fail to induce the tumoricidal activity indicating mechanistically PON2 enhances the tumoricidal activity via IL18 dependent manner. Furthermore, IL18 levels are increased in tumor micro environment. PON2 increase the IL18 through transactivation of c-Myc gene that are independent of mitochondrial function. Conclusion: Taken together, our study for the first time showed that PON2 enhances the tumerocidal activity via paracrine manner by upregulating IL18 and PON2 could be used as conventional as well as immunotherapy for ovarian cancer. Citation Format: Asokan Devarajan, Dawoud Sulaiman, Feng Su, Ekambaram Ganapathy, Robin Farias-Eisner, Srinivasa Reddy. Cardioprotective paraoxonase 2 enhances the tumoricidal activity of natural killer cells in a paracrine manner [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3309.

Abstract 976: The systematic identification of novel immune checkpoint averting the metastasis of ovarian cancer: The role of IL20/IL24-IL20RA axis

Abstract Ovarian cancer has high mortality among all gynecological malignancies due to the lack of clear symptoms at early stage and the metastasis of cancer cells when diagnosed with advanced stage. The disseminated ovarian cancer cells have to overcome the immune surveillance in abdominal environment, which are rich in many types of immune cells, to survive and proliferate. However, the key genes and mechanisms preventing the metastasis of ovarian cancer cells into abdominal sites keep largely unexplored. Here, through an in vivo, genome-scale CRISPR/Cas9 knockout screening, we identified IL-20/IL24-IL20RA as a key checkpoint preventing the abdominal metastasis of ovarian cancer cells. In ovarian cancer patients, the level of IL20RA is dramatically decreased in metastatic cancer cells when compared with that in primary sites. Overexpression of IL20RA in highly metastatic ovarian cancer cells greatly suppressed the abdominal metastasis of ovarian cancer and the formation of ascites. In contrast, silencing IL20RA could increase the metastasis of ovarian cancer cells. We further examined IL20RA mediated crosstalk between the disseminated cancer cells and the immuno-microenvironment in mouse in vivo ovarian cancer models and in vitro co-culture experiments. Silencing IL20RA in ovarian cancer cells resulted in a dramatic decrease of M1 subtype of macrophages and increase of the M2 subtype of macrophages without affecting the population of T and B lymphocytes in ascites. Further mechanistic studies revealed that the ovarian cancer cells, when invaded into the abdominal sites, greatly induced the mesothelial cells in peritoneum to produce IL20RA ligands, i.e., IL-20 and IL-24, which in turn activated the IL20RA downstream signaling in ovarian cancer cells to trigger the production and maturation of IL-18. IL-18, when secreted into the microenvironment, was able to promote the polarization of macrophages into M1-subtype to clear the cancer cells. Thus, we identified a novel immune checkpoint IL-20/IL24-IL20RA that was always downregulated in metastatic ovarian cancer cells to prevent the formation of an anti-tumor immune microenvironment, which could be utilized to develop new strategies for the immunotherapy of ovarian cancers. Citation Format: Jia Li, Qin Xuan, JIE SHI, Longlong Wang, Yi Shi, Rong Xiang. The systematic identification of novel immune checkpoint averting the metastasis of ovarian cancer: The role of IL20/IL24-IL20RA axis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 976.

Immunotherapies in ovarian cancer

Ovarian cancer is the leading cause of death for gynaecological cancer, and new therapies are urgently awaited. Although the presence of tumour-infiltrating lymphocytes has been confirmed to be associated to a better prognosis, immunotherapy is not yet incorporated to the armamentarium in ovarian cancer. This review briefly summarises the strategies that have been tested or are under study for the three different groups of tumours: immune desert, inflamed and immune-excluded ovarian tumours. Finally, a better knowledge of the biology and immune microenvironment is needed for successfully developing new immunotherapy strategies.

Specific targeting of ovarian tumor-associated macrophages by large, anionic nanoparticles

Immunotherapy is emerging as one of the most effective methods for treating many cancers. However, immunotherapy can still introduce significant off-target toxicity, and methods are sought to enable targeted immunotherapy at tumor sites. Here, we show that relatively large (>100-nm) anionic nanoparticles administered intraperitoneally (i.p.) selectively accumulate in tumor-associated macrophages (TAMs). In a mouse model of metastatic ovarian cancer, fluorescently labeled silica, poly(lactic-co-glycolic acid), and polystyrene nanoparticles administered i.p. were all found to selectively accumulate in TAMs. Quantifying silica particle uptake indicated that >80% of the injected dose was in TAMs. Particles that were smaller than 100 nm or cationic or administered intravenously (i.v.) showed no TAM targeting. Moreover, this phenomenon is likely to occur in humans because when freshly excised human surgical samples were treated with the fluorescent silica nanoparticles no interaction with healthy tissue was seen but selective uptake by TAMs was seen in 13 different patient samples. Ovarian cancer is a deadly disease that afflicts ∼22,000 women per year in the United States, and the presence of immunosuppressive TAMs at tumors is correlated with decreased survival. The ability to selectively target TAMs opens the door to targeted immunotherapy for ovarian cancer.

Immunotherapy in gynecological cancers: where are we?

This manuscript discusses the clinical evidence on immunotherapy for ovarian, endometrial, and cervical cancer. We report here the results of the clinical trials and present the ongoing trial in this area. Immunotherapy has become a pillar of cancer treatment improving the prognosis of many patients with a broad variety of solid malignancies. Unfortunately, until recently the progress achieved in some other tumors has not been seen in the majority of patients with gynecological cancer. Except for some subgroups of endometrial cancers the immune checkpoint inhibitors in monotherapy have shown unsatisfactory results. However, several combinations of immunotherapy with other drugs are under investigation and are very promising. It is essential, to develop tools to select the patients who will response best to immunotherapy. Combined immune checkpoint inhibitors with targeted therapies are awaited in gynecological cancers and could provide additional benefit.

Abstract IA19: Immunotherapy in ovarian cancer: Challenges and novel opportunities

Abstract IA19: Immunotherapy in ovarian cancer: Challenges and novel opportunities

Abstract B03: Immunotherapy of ovarian cancer with glycomimetic peptides

Abstract Successful strategies for treating women with ovarian cancer remain elusive. Whereas chemotherapy with drugs such as paclitaxel and carboplatin extends survival, it bears a significant cost in toxicity. Immunotherapies with antibodies such as anti-PD-1, anti-PD-L1, or anti-VEGF have been successful in a fraction of patients. Inhibitors of poly(ADP-ribose) polymerase (PARP) have gained interest, particularly for the minority of patients who carry the BRCA-1/2 mutations. Ovarian cancer is highly inflammatory and recent reports described recruitment of monocytes, which then differentiate into a unique subset of dendritic cells (DCs) within the inflamed ascites environment. These monocyte-derived DCs (mo-DCs) have the potential to activate cytotoxic CD8+ T cells that attack tumor cells, but progression of disease is not abrogated without additional stimuli. We hypothesize that a means to actuate this role of mo-DCs will be an important component of a successful treatment of inflammatory tumors such as ovarian ascites. Mo-DCs along with CD1c+ DC2 subtypes express CD301, the Ca2+-dependent lectin domain family 10 member A (CLEC10A), which is a pathogen-recognition receptor specific for binding the ligand N-acetylgalactoasmine (GalNAc). A series of experiments were designed to test whether a novel peptide mimetic of GalNAc, designated sv6D, can enhance anticancer immune activity and limit the progression of ovarian cancer. CLEC10A is a type II transmembrane receptor that initiates a Ca2+ signal upon binding of sv6D and subsequent endocytosis. Production of IFN-γ by naïve T cells occurred when cultured with in vitro generated mo-DCs, which are similar to mo-DCs induced by inflammation, and 10 nM sv6D. In a syngeneic, orthotopic murine model of ovarian cancer, doses of 0.1 nmole/g of sv6D on alternate days completely suppressed ascites accumulation for several weeks, a measure of inhibition of tumor progression. Survival was also extended when sv6D was administered to mice previously treated with paclitaxel. Although treatment with anti-PD-1 was ineffective, i.p. injections of anti-PD-1 in combination with a tolerance-inducing treatment with sv6D provided maximal survival. Our studies demonstrate that 1) sv6D stimulates proliferation and differentiation of immune cells in the peritoneal cavity and serves as a trigger to promote the activation of CD8+ T cells by mo-DCs in ovarian ascites, 2) sv6D as a single agent inhibits progression of ovarian cancer and enhances survival in a mouse model of ovarian cancer, 3) sv6D in combination with paclitaxel or anti-PD-1 extends survival beyond that of either agent alone, and 4) sv6D is not antigenic and treatment with the peptide was not associated with evident toxicity. Taken together, these data demonstrate the potential for this novel approach of harnessing lectin receptors as a means toward an effective ovarian cancer treatment. Citation Format: Laura L. Eggink, J. Kenneth Hoober. Immunotherapy of ovarian cancer with glycomimetic peptides [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B03.

Clinical outcomes of prexasertib monotherapy in recurrent BRCA wild-type high-grade serous ovarian cancer involve innate and adaptive immune responses

BackgroundPreclinical data suggest cell cycle checkpoint blockade may induce an immunostimulatory tumor microenvironment. However, it remains elusive whether immunomodulation occurs in the clinical setting. To test this, we used blood...

Abstract B61: The genotype of serous carcinomas shapes the tumor microenvironment and modulates responses to targeted and immune checkpoint therapies

Abstract Immunotherapy in ovarian cancer has been disappointing, with only ~10% of patients responding to checkpoint blockade. The determinants of this low response rate remain poorly understood and there is a pressing need for immune-competent preclinical models to elucidate the biology of immune evasion in ovarian cancer. One critical area of interest is the role of homologous recombination (HR) DNA repair in immune evasion. The types and abundance of potential antigens present on cancer cells may depend on the genotype of the tumor, its mutational burden, and the cellular state. Unfortunately, the preclinical tools required to explore the relationship between the types of DNA damage repair deficiencies and immune evasion have been lacking. To this end, we have engineered novel syngeneic mouse models from murine fallopian tube epithelium using CRISPR/Cas9 technology. These tumors capture the most common combinations of co-occurring mutations observed in homologous recombination-deficient and -proficient patient samples. These models can identify the contribution of common driver mutations, which are TP53, BRCA1, PTEN, MYC, Cyclin E1 (CCNE1), AKT2, and Kras, to the heterotypic interactions between cancer and stromal/immune compartments and examine how DNA repair proficiency contributes to immunogenicity. To validate the DNA repair proficiency of the transformed cells, we measured Rad51 nuclear focus formation after ionizing radiation (IR) and PARP inhibitor and DNA-damaging agent sensitivity. The HR-deficient cell lines had significantly fewer Rad51 nuclear foci and were more sensitive to PARP inhibition in comparison to HR-proficient cells. Initial immune/stromal analysis using flow cytometry, single-cell RNASeq (scRNASeq) transcriptomic, and immunofluorescence imaging analysis revealed substantial differences in the myeloid and T-cell regulatory compartments between HR-proficient and -deficient primary and metastatic tumors and within the ascitic fluid. Preliminary results also suggest that inhibition of the DNA damage response (DDR), checkpoint kinase 1 (Chk1) in combination with immune checkpoint inhibitors, potentiates antitumor effects and augments cytotoxic T-cell infiltration. In conclusion, these results reveal how common mutational drivers, and particularly those associated with HR status, determine the microenvironment of the tumor and its response to treatment. Understanding the genetic basis of these complex cellular interactions will be critical to better tailor combinations of existing targeted treatments and immunotherapies in ovarian cancer to fight this devastating disease. Citation Format: Sonia Iyer, Shuang Zhang, Anniina Farkkila, Sean Smith, David Pepin, Raghav Mohan, Tian Xia, Ferenc Reinhardt, Tony Chavarria, Esmee Hoefsmit, Vera Poort, Shailja Pathania, Yunlan Zhou, Kevin M. Elias, Paula T. Hammond, Benjamin G. Neel, Robert A. Weinberg. The genotype of serous carcinomas shapes the tumor microenvironment and modulates responses to targeted and immune checkpoint therapies [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B61.

Abstract IA21: MUC16-directed immunotherapy for ovarian cancer

Abstract Despite recent setbacks in the clinical development of immunotherapy for gynecologic malignancies, the promise of durable responses with this form of treatment has led to a redoubling of our efforts to understand and develop new immunotherapeutic modalities. Some of the reasons behind the relative lack of success of immunotherapy in ovarian cancer include low tumor antigenic burden; a hostile tumor microenvironment (TME) consisting of physical barriers to immune infiltration; suppressive ligands, cytokines, chemokines, and other immunosuppressive cellular elements. There are ongoing efforts to overcome many of these limitations simultaneously. For instance, several clinical trials are exploring the combination of immune checkpoint blockade with chemotherapy, poly (ADP-ribose) polymerase (PARP) inhibitors, or both in an attempt to increase tumor antigenic burden. Other approaches are centered around targeting known tumor-associated antigens such as MUC16. MUC16 is amplified in 5-10% of ovarian cancers. The predominant extracellular portion of MUC16 is cleaved and secreted (referred to as CA-125), although a significant portion of the antigen is retained on the surface of the tumor (referred to as MUC16ecto). We have developed a variety of MUC16ecto- directed therapies, including chimeric antigen receptor (CAR) T-cells and bispecific T-cell engager cells (BiTEs). Targeting MUC16ecto solves the problem of low tumor mutational burden in ovarian cancer, but further optimizations are required to overcome the immunosuppressive TME. For our CAR T-cell therapy, we devised and evaluated three separate approaches to overcome the TME in ovarian cancer. MUC16ecto-directed CAR T-cells modified to secrete interleukin-12 (IL-12) showed superior efficacy in advanced syngeneic and xenograft murine models of metastatic ovarian cancer. We found that autocrine and paracrine activity of IL-12 potentiated the activity of these CAR T-cells and mediated resistance to PD-L1 suppression. Furthermore, we found that secretion of IL-12 in the TME promoted differentiation of proinflammatory tumor-associated macrophages and led to the deletion of other suppressive macrophages in the TME. Similarly, MUC16ecto-directed CAR T-cells modified to secrete interleukin-18 (IL-18) significantly improved survival in low and high tumor burden syngeneic models of metastatic ovarian cancer. We also evaluated CAR T-cells engineered to secrete anti-PD-1 blocking single-chain variable fragments (scFv) and showed that this approach significantly improved efficacy in relevant preclinical models of metastatic ovarian cancer. Furthermore, this approach fostered CAR T-cell persistence leading to resistance to tumor rechallenge. Unsurprisingly, using CAR T-cells as a delivery vehicle for delivery of immune checkpoint blockade promoted bystander effects on endogenous immune cells and mitigated systemic anti-PD-1 leak. We next evaluated MUC16ecto-specific BITEs and found a significant reduction in tumor burden in xenogeneic models of metastatic ovarian cancer. Adjunctive therapies to augment our MUC16ecto-specific BiTEs are currently in testing, along with other MUC16-directed immunotherapeutic strategies. Citation Format: Oladapo O. Yeku, Sarwish Rafiq, Mythili Koneru, Terence J. Purdon, Mei Song, Pei Wang, Ronald Hendrickson, Renier J. Brentjens, David Spriggs. MUC16-directed immunotherapy for ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA21.

Abstract PR07: Reprogramming the tumor microenvironment with losartan to enhance immunotherapy of ovarian cancer

Abstract Ovarian cancer (OvCa) is the most lethal of the gynecologic malignancies. Immune checkpoint blockers (ICBs) and chimeric antigen receptor (CAR)-T cells—which have revolutionized the treatment of multiple malignancies—have had limited efficacy in OvCa patients. This lack of efficacy is partly due to abnormal extracellular matrix (ECM) deposition leading to a buildup of compressive forces that induce vessel collapse, hypoperfusion, poor delivery of nutrients and drugs, and compromised trafficking of cytotoxic T cells to these tumors. The resulting tumor microenvironment (TME) is also hypoxic, acidic, and immunosuppressive. Our overarching hypothesis is that losartan, an FDA-approved antihypertensive drug that blocks angiotensin signaling, can overcome these challenges by normalizing the TME to enhance the delivery and efficacy of therapies in OvCa. Retrospective study showed that treatment with angiotensin blockers is associated with a 30-month overall survival benefit in OvCa patients. In our OvCa models, losartan reduced matrix content and reopened compressed vessels. As a result, blood perfusion increased, leading to enhanced drug delivery and improved chemotherapy efficacy. Losartan also relieved lymphatic vessel collapse in the diaphragm, which increased the drainage of peritoneal fluid and reduced ascites. Using unbiased RNASeq analysis, we found that in addition to normalizing the tumor matrix and vasculature, losartan treatment also activates immune response pathways. Furthermore, losartan increases the infiltration and function of immune effector cells and improves the outcome of immunotherapy using ICBs. Our findings provide the rationale and supporting data for a clinical trial on combined losartan and immunotherapy in ovarian cancer patients. This abstract is also being presented as Poster B75. Citation Format: Yao Sun, Wenjianlong Zhao, David R. Spriggs, Rakesh K. Jain, Lei Xu. Reprogramming the tumor microenvironment with losartan to enhance immunotherapy of ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr PR07.

IRE1α-XBP1 Signaling as a Mechanism of Resistance to Immunotherapy in Ovarian Cancer

Objectives: Adverse conditions in the ovarian cancer (OvCa) tumor microenvironment (TME) result in sustained activation of the inositol-requiring enzyme 1 alpha (IRE1α)-X-box binding protein 1 (XBP1) arm of the endoplasmic reticulum (ER) stress response. This evokes chronic changes in immunometabolic processes that subsequently inactivate the anti-tumor functions of dendritic cells and T cells, thereby creating an immunosuppressive TME capable of the limiting the effectiveness of immunotherapies in OvCa.

Bispecific T-cell engager (BiTE) immunotherapy of ovarian cancer based on MIL-88A MOF/MC gene delivery system

Bispecific T-cell engager (BiTE) immunotherapy is a promising therapy for cancer treatment. However, the high cost and short life-time in vivo of the BiTE limit its wide clinical application. Here, we built for the first time a gene delivery system based on MIL-88A metal organic framework nanoparticles and minicricle DNA (MOF/MC) to realize high-efficient in vivo expression of anti-CD3/anti-EpCAM BiTE. X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS) analysis verified that MC molecules were loaded onto MOF nanoparticles through metal-phosphate bonds and electrostatic interactions. It is found that intraperitoneal injection (i.p.) of MOF/MC suspensions showed good transfection performance in mice abdominal cavity with low toxicity. In an intraperitoneal xenograft mice model established using SKOV3 ovarian cells, i.p. injection of MOF/MC.BiTE significantly inhibited tumor growth and prolonged the average survival time of the mice. Overall, our study demonstrates a simple and highly efficient MOF-based gene delivery system holding promise for effective ovarian cancer immunotherapy.

Immunotherapy For Ovarian Cancer: Recent Advances And Combination Therapeutic Approaches.

Epithelial ovarian cancer (EOC) is the most lethal gynaecological cancer. Although many advances have been made in therapeutic strategies, the global standard of care still remains radical surgery plus chemotherapy, but new scenarios need to be explored to improve survival. The role of immunotherapy in EOC treatment is controversial. Results obtained from studies evaluating immunotherapy are contradictory: in particular data on survival are not as good as expected when immunotherapy was administered alone, and other data are still immature. Thus, significant efforts must be devoted to finding new strategies for the use of immunotherapy. The aim of this paper is to review the most recent findings of the use of immunotherapy in ovarian cancer, with a particular focus on combination approaches.

A phase I combination study of vigil and atezolizumab in recurrent/refractory advanced-stage ovarian cancer: Efficacy assessment in BRCA1/2-wt patients.

3002 Background: Recent studies have shown poor clinical outcomes and limited survival advantage to checkpoint inhibitors (CIs) in advanced stage ovarian cancer (OvC). Vigil is a personalized precision vaccine constructed from autologous tumor tissue transfected with a DNA plasmid encoding GM-CSF and bi-shRNA-furin thereby creating TGFβ expression control and enhancing immune activation. Phase 1 and 2 trials in OvC demonstrate safety, functional immune activation and clinical response benefit. Combining Vigil with CIs may broaden responsiveness of immunotherapy in OvC. Methods: This is a randomized, 3-part safety Phase 1 study of Vigil in combination with Atezolizumab in recurrent OvC patients. Part 2 is a randomized, intra-patient crossover study of Vigil first (VF) or Atezolizumab first (AF) for two cycles followed by sequence of the combination of the two agents. Vigil (1 x 106 or 1 x 107 cells/ml) or Atezolizumab (1200mg) were administered 1x every 21 days each cycle until progression or untoward adverse event. We now report the preliminary results of part 2 of the study. Results: Twenty-one patients were randomized (1:1) to VF (n = 11) or AF (n = 10), groups were similar in demographics. Grade 3/4 toxic events occurred in 17% of AF patients compared to 3% in VF patients. Median OS of VF patients (n = 11) was not reached vs. AF (n = 10) 10.8 months suggested modest advantage to VF (HR 0.33, one-sided p 0.097). However, the subset analysis of BRCA1/2 wild type (wt) demonstrated more significant overall survival benefit in VF (n = 7) median OS not reached vs. AF (n = 7) 5.2 months (HR 0.12, one-sided p 0.015). Conclusions: The combination of Vigil immunotherapy and checkpoint inhibitor atezolizumab in recurrent OvC demonstrated safety and suggest a lower toxicity profile and a significant OS advantage in recurrent BRCA1/2-wt OvC patients treated with Vigil first followed by the combination of Vigil and Atezolizumab. Clinical trial information: NCT03073525 . [Table: see text]

Immunotherapy of ovarian cancer with a monoclonal antibody specific for the extracellular domain of anti-Müllerian hormone receptor II.

Epithelial ovarian carcinoma (EOC) is the most prevalent and lethal form of ovarian cancer. The low five-year overall survival after EOC diagnosis indicates an urgent need for more effective ways to control this disease. Anti-Müllerian hormone receptor 2 (AMHR2) is an ovarian protein overexpressed in the majority of human EOCs. We have previously found that vaccination against the ovarian-specific extracellular domain of AMHR2 (AMHR2-ED) significantly inhibits growth of murine EOCs through an IgG-mediated mechanism that agonizes receptor signaling of a Bax/caspase-3 dependent proapoptotic cascade. To determine if a single monoclonal antibody (mAb) could inhibit growth of human EOC, we generated a panel of mAbs specific for recombinant human AMHR2-ED and characterized a candidate mAb for humanization and use in clinical trials. We found that our candidate 4D12G1 mAb is an IgG1 that shows high affinity antigen-specific binding to the 7-mer 20KTLGELL26 sequence of AMHR2-ED that facilitates induction of programmed cell death in EOC cells. Most importantly, the 4D12G1 mAb significantly inhibits growth of primary human EOCs in patient-derived xenografts (PDXs) by inducing direct apoptosis of EOC tumors. Our results support the view that a humanized 4D12G1 mAb may be a much needed and effective reagent for passive immunotherapy of human EOC.

MiR-140-3p inhibits natural killer cytotoxicity to human ovarian cancer via targeting MAPK1

Natural killer (NK) cells have pivotal role in immunotherapy of human ovarian cancer (OC). Although microRNAs (miRNAs) participate in dysfunction of NK cells, how and whether miR-140-3p regulates cytotoxicity of NK cells in OC are uncertain. miR-140-3p and mitogen activated protein kinase 1 (MAPK1) abundances were examined via quantitative real-time polymerase chain reaction or western blot. Tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) abundances were examined via enzyme linked immunosorbent assay. NK cytotoxicity to OC was evaluated via lactate dehydrogenase release. The relevance of miR-140-3p and MAPK1 was proved via luciferase activity analysis. Murine xenograft experiment was applied to assess the function of miR-140-3p on NK cytotoxicity. miR-140-3p was elevated and MAPK1 was declined in NK cells from OC patients, while the levels were reversed after treatment of interleukin-2 (IL-2). MiR-140-3p addition mitigated IFN-γ and TNF-α production induced via IL-2 as well as NK-92 cytotoxicity to OC cells. Additionally, MAPK1 was negatively regulated via miR-140-3p and ablated the influence of miR140-3p on cytotoxicity, cytokines levels. Besides, miR-140-3p enrichment facilitated tumor growth via suppressing function of NK cells in a xenograft model. miR-140-3p suppressed NK cytotoxicity to OC cells via mediating MAPK1, indicating a new avenue of ameliorating NK cells function for OC treatment.