Ovarian Cancer Tumor-associated Macrophages Research Articles

Abstract IA006: Friend or foe: Reevaluating the therapeutic potential of monocytes and tumor-associated macrophages in ovarian cancer

Abstract The hostile tumor microenvironment in ovarian cancer is an active deterrent to the efficacy of immunotherapeutic agents such as immune checkpoint inhibitors, Chimeric Antigen Receptor (CAR) T-cells, and Bispecific T-cell Engagers (BiTEs). Tumor-associated macrophages (TAMs) and Myeloid-Derived Suppressor Cells (MDSCs) have been shown to promote an immunosuppressive metabolic and cytokine tumor microenvironment that is detrimental to cytotoxic effector T-cell activity in ovarian cancer. These immunosuppressive cells are also associated with poor prognostic outcomes. The ideal approach to modulating TAMs and MDSCs is unknown. Data from preclinical models support reprogramming these cells to a more inflammatory phenotype or removing them from the tumor microenvironment entirely. However, neither approach has translated to clinical benefits. We have previously demonstrated that CAR-T cells modified to secrete IL-18 exerted their therapeutic effects partly via polarization of bone marrow macrophages towards an M1 phenotype. We also found that the depletion of TAMs improved CAR-T cell efficiency, even when these CAR-T cells were co-modified to secrete IL-12. Because of the propensity for monocytes to be recruited to the ovarian cancer tumor microenvironment, we evaluated the efficacy of monocytes genetically modified to secrete BiTEs. First, we designed and evaluated BiTEs that recognize the retained portion of MUC16 (Muc16-ecto) and CD3+ T-cells and showed that these BiTEs were efficacious in vitro and in vivo in a xenograft model of ovarian cancer. We validated that monocytes transduced to secrete Muc16-specific BiTEs (Mono-BiTEs) could effectively lyse tumor cells in vitro and suppress xenograft ovarian cancer cells in vivo. Adding IFN-alpha and IFN-gamma to Mono-BiTEs significantly improved Mono-BiTEs antitumor efficacy over BiTE therapy or unmodified monocyte therapy alone. Adoptive cell therapy with genetically engineered autologous monocytes could provide an alternative approach to reprograming or eliminating myeloid-derived cells in ovarian cancer. Citation Format: Oladapo Yeku. Friend or foe: Reevaluating the therapeutic potential of monocytes and tumor-associated macrophages in ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr IA006.

Signatures of tumor-associated macrophages correlate with treatment response in ovarian cancer patients.

Ovarian cancer (OC) ranks as the second leading cause of death among gynecological cancers. Numerous studies have indicated a correlation between the tumor microenvironment (TME) and the clinical response to treatment in OC patients. Tumor-associated macrophages (TAMs), a crucial component of the TME, exert influence on invasion, metastasis, and recurrence in OC patients. To delve deeper into the role of TAMs in OC, this study conducted an extensive analysis of single-cell data from OC patients. The aim is to develop a new risk score (RS) to characterize the response to treatment in OC patients to inform clinical treatment. We first identified TAM-associated genes (TAMGs) in OC patients and examined the protein and mRNA expression levels of TAMGs by Western blot and PCR experiments. Additionally, a scoring system for TAMGs was constructed, successfully categorizing patients into high and low RS subgroups. Remarkably, significant disparities were observed in immune cell infiltration and immunotherapy response between the high and low RS subgroups. The findings revealed that patients in the high RS group had a poorer prognosis but displayed greater sensitivity to immunotherapy. Another important finding was that patients in the high RS subgroup had a higher IC50 for chemotherapeutic agents. Furthermore, further experimental investigations led to the discovery that THEMIS2 could serve as a potential target in OC patients and is associated with EMT (epithelial-mesenchymal transition). Overall, the TAMGs-based scoring system holds promise for screening patients who would benefit from therapy and provides valuable information for the clinical treatment of OC.

GATA3 as a master regulator for interactions of tumor-associated macrophages with high-grade serous ovarian carcinoma

High-grade serous ovarian carcinoma (HGSOC) is the most lethal gynecologic cancer. Emerging evidence suggests that tumor-associated macrophages (TAMs) play an immunosuppressive role in the tumor microenvironment and promote tumor growth, angiogenesis, and metastasis in ovarian cancer. Therefore, targeting TAMs in patients with ovarian cancer is an appealing strategy; however, all trials to date have failed. To improve the efficacy of this approach, we sought to elucidate the underlying mechanisms of the role of TAMs in ovarian cancer. We found that the developmental transcription factor GATA3 was highly expressed in HGSOC cell lines but not in the fallopian tube, which is the main origin of HGSOC. GATA3 expression was associated with poor prognosis in HGSOC patients (P < .05) and was found to promote proliferation and migration in HGSOC cell lines. GATA3 was released abundantly from TAM cells via exosomes and contributed to tumor growth in the tumor microenvironment. Moreover, GATA3 acted as a regulator for macrophage polarization and interactions between TAMs and HGSOC to support proliferation, motility, and cisplatin chemoresistance in mutant TP53 HGSOC cell lines. Furthermore, GATA3 played a critical role in the interactions between TAMs and mutant TP53 HGSOC to promote angiogenesis and epithelial-mesenchymal transition with epigenetic regulation. Targeting GATA3 using GATA3siRNA in TAMs impeded GATA3-driven proliferation, migration, cisplatin chemoresistance, and angiogenesis in mutant TP53 HGSOC cell lines. Our findings indicate that GATA3 plays a novel role in immunoediting of HGSOC and demonstrate that GATA3 may serve as a prognostic marker for HGSOC and a promising target in the treatment of HGSOC.

Abstract 3563: Exosomal transfer of tumor-associated macrophage derived miR-6068 promote ovarian cancer progression

Abstract Ovarian cancer, especially high-grade serous ovarian cancer (HGSOC), is the deadliest gynecological cancer with 50-70% 5-year mortality rates. Every year more than 22,000 new cases of ovarian cancer and 15,000 deaths are anticipated within the United States only. Recent clinical and experimental evidence indicates that tumor-associated macrophages (TAMs), the most abundant cells in the tumor microenvironment, play a significant role in tumor growth and progression by contributing to angiogenesis, invasion, metastasis, and drug resistance, leading to poor clinical outcomes and significantly shorter patient survival in HGSOC. More than 50% of cells in the peritoneal tumor microenvironment and malign ascites consist of TAMs in ovarian cancer (OC) patients. Especially, M2 macrophages have been shown to support tumor proliferation and promote tumor progression, angiogenesis, and drug resistance. But the mechanisms of these oncogenic effects are still not clear. The goal of our study to investigate the role of TAM-derived exosomes, which are 30-100nm microvesicles released from cells and are key factors in communication between cancer cells and the tumor microenvironment. To this end, we evaluated differentially expressed miRNAs in high-grade ovarian cancer cells (OVCAR3, OVCAR 432 and OVCAR5) after treatment with exosomes-derived from TAMs (M2 phenotype) using the Affymetrix Gene Chip miRNA 4.0 microarrays. We identified several miRNAs, including miR-6068 that we validated by qPCR and found it to be significantly upregulated in both HGSOC cells and their exosomes. We demonstrated that transfection of HGSOC cells with miR-6068 significantly increased proliferation, migration and invasion capacities of the cells in vitro, suggesting that this miR-6068 act as an oncogenic miR (oncomiR). Using in silico prediction algorithms we found that miR-6068 has binding sites on the 3’-untranslated region (3’-UTR) of PTPN4 gene encoding a phosphatase and demonstrated that it miR-6068 suppresses PTPN4 expression by Western blot and qPCR. Inhibition of PTPN4 by siRNA significantly induced cell proliferation in OC cells, suggesting that PTPN4 acts as a tumor suppressor. In conclusion, our results suggest that miR-6068 has an oncogenic role in ovarian cancer progression by targeting PTPN4 and may be a novel effective therapeutic target for ovarian cancer. Citation Format: Seyda Baydogan, Jianting Sheng, Nermin Kahraman, Pinar Kanlikilicer, Hamada Ahmed Mokhlis, Sayra Dilmac, Stephen T. C. Wong, Bulent Ozpolat. Exosomal transfer of tumor-associated macrophage derived miR-6068 promote ovarian cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3563.

Expression and antibody-directed targeting of folate receptor beta in ovarian cancer tumor-associated macrophages

Objective: Tumor-associated macrophages (TAMs) are associated with poor outcomes in ovarian cancer because of their immunosuppressive, protumor, and proangiogenic factors. This subset of macrophages is thought to express folate receptor beta (FRβ); therefore, we analyzed patient ascites samples for expression of FRβ and the ability of an anti-FRβ antibody (m909) to mediate antibody-dependent cellular cytotoxicity (ADCC).

Intestinal dysbiosis promotes epithelial-mesenchymal transition by activating tumor-associated macrophages in ovarian cancer.

We aimed to investigate the relationship of intestinal dysbiosis (IDB) and ovarian cancer progression, and understand its underlying signaling mechanisms. IDB was induced with high dose antibiotics. The xenograft mouse model was used to assess the tumor progression. Real-time polymerase chain reaction and immunoblotting are commonly used quantitative methods, and they were used to quantify epithelial-mesenchymal transition (EMT) markers in this paper. Meanwhile, cellular proliferation was also measured. First, IDB could promote the growth of xenograft tumors and induce the EMT. Serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 also increased remarkably. In addition, the production and secretion of TNF-α and IL-6 in macrophages isolated from IDB model mice were observably higher. In vitro, conditioned medium could significantly stimulate the development of EMT in ovarian cancer cells. Loss of macrophages completely offset the pro-tumor effects of IDB. IDB can stimulate the activation of tumor-associated macrophages in ovarian cancer, which is achieved by secreting pro-inflammatory cytokines IL-6 and TNF-α, and ultimately induces the development of EMT.

Bipolar Tumor-Associated Macrophages in Ovarian Cancer as Targets for Therapy.

Ovarian cancer, a rare but fatal disease, has been a challenging area in the field of gynecological cancer. Ovarian cancer is characterized by peritoneal metastasis, which is facilitated by a cross-talk between tumor cells and other cells in the tumor microenvironment (TME). In epithelial ovarian cancer, tumor-associated macrophages (TAMs) constitute over 50% of cells in the peritoneal TME and malignant ascites, and are potential targets for therapy. Here, we review the bipolar nature of TAMs and the evolving strategies to target TAMs in ovarian cancer.

The ecto-ATPDase CD39 is involved in the acquisition of the immunoregulatory phenotype by M-CSF-macrophages and ovarian cancer tumor-associated macrophages: Regulatory role of IL-27

ABSTRACTTumor-associated macrophages (TAM) are immunosuppressive cells that can massively accumulate in the tumor microenvironment. In patients with ovarian cancer, their density is correlated with poor prognosis. Targeting mediators that control the generation or the differentiation of immunoregulatory macrophages represents a therapeutic challenge to overcome tumor-associated immunosuppression. The ectonucleotidase CD39 hydrolyzes ATP into extracellular adenosine that exhibits potent immunosuppressive properties when signaling through the A2A adenosine receptor. We report here that CD14+ CD163+ TAM isolated from ovarian cancer patients and macrophages generated in vitro with M-CSF, express high levels of the membrane ectonucleotidase CD39 compared to classically activated macrophages. The CD39 inhibitor POM-1 and adenosine deaminase (ADA) diminished some of the immunosuppressive functions of CD14high CD163high CD39high macrophages, such as IL-10 secretion. We identified the cytokine IL-27, secreted by tumor-infiltrating neutrophils, located close to infiltrating CD163+ macrophages, as a major rheostat of CD39 expression and consequently, on the acquisition of immunoregulatory properties by macrophages. Accordingly, the depletion of IL-27 downregulated CD39 and PD-L1 expression as well as IL-10 secretion by M-CSF-macrophages. Collectively, these data suggest that CD39, drived by IL-27 and CD115 ligands in ovarian cancer, maintains the immunosuppressive phenotype of TAM. This work brings new information on the acquisition of immunosuppressive properties by tumor-infiltrating macrophages.

Attenuated listeria monocytogenes reprograms M2-polarized tumor-associated macrophages in ovarian cancer leading to iNOS-mediated tumor cell lysis (TUM4P.908)

Abstract A principal mechanism by which tumors evade immune-mediated elimination is through immunosuppression. Previous approaches to tumor immunotherapy have focused on modifying the immunosuppressive environment with immune checkpoint inhibitors, cytokine therapy, and other modalities with the intent to generate T-cell based anti-tumor immunity. We hypothesized that transformation of the suppressive ovarian cancer microenvironment could be achieved by introduction of the attenuated ΔactA/ΔinlB strain of Listeria monocytogenes. ΔactA/ΔinlB introduced into the microenvironment of the aggressive ID8-Defb29/Vegf-A murine ovarian carcinoma is preferentially phagocytosed by tumor-associated macrophages (TAMs) and reprograms that population from one of suppression to immunostimulation. TAMs in the peritoneum upregulated their co-stimulatory molecules CD80 and CD86, increased transcription of inflammatory cytokines, and downregulated transcription of suppressive effector molecules. Surprisingly, therapeutic benefit was not mediated by T- or NK-cell activity. ΔactA/ΔinlB-induced repolarization of TAMs activated direct tumor cell lysis via Nos2 production of nitric oxide. Modulation of the immunosuppressive nature of the ID8-Defb29/Vegf-A microenvironment, specifically by reprogramming of the TAM suppressive population from M2 to M1 polarization, is critical for our observed immune-mediated survival benefit.