Novel therapeutic strategies for advanced ovarian cancer by using induced pluripotent stem cell-derived myelomonocytic cells producing interferon beta.

Although first-line chemotherapy has a high rate of complete responses in ovarian cancer patients, the vast majority of patients present with recurrent disease that has become refractory to conventional chemotherapy. Peritoneal dissemination and malignant ascites are the hallmarks of recurrent or advanced ovarian cancer and severely reduce quality of life. Development of therapeutic measures to treat such patients is eagerly anticipated. Macrophage infiltration is observed in various types of cancer including epithelial ovarian cancer. In addition, macrophages are involved in the formation of spheroids in the malignant ascites of ovarian cancer and promote cancer growth. iPS-ML, macrophage-like myelomonocytic cells generated from human induced pluripotent stem (iPS) cells, made close contacts with ovarian cancer cells in vitro. We hypothesized that, if we inoculate iPS-ML-producing IFN-ß (iPS-ML/IFN-ß) into the peritoneal cavity of patients with ovarian cancer, IFN-ß produced by the iPS-ML/IFN-ß would efficiently act on the cancer cells to suppress cancer growth. To evaluate this hypothesis, we injected iPS-ML/IFN-ß into SCID mice bearing peritoneally disseminated human ovarian cancer cells, SKOV3. Immunohistochemical analysis of the intraperitoneal tumors detected iPS-ML/IFN-ß infiltrating into the cancer tissues. Therapy with iPS-ML/IFN-ß significantly suppressed tumor progression. In addition, dramatic reduction of cancer-related ascites was observed. Collectively, it is suggested that iPS-ML/IFN-ß therapy offers a new approach for the treatment of patients with advanced ovarian cancer.

CD163 Is Required for Protumoral Activation of Macrophages in Human and Murine Sarcoma.

Recent findings have shown the significance of CD163-positive macrophages in tumor progression, yet there have been few studies on the function of CD163 in macrophages. Here, we uncover the role of CD163 in macrophage activation using CD163-deficient mice and human samples. We detected CD163 in 62 undifferentiated pleomorphic sarcoma samples, in which a high percentage of CD163-positive macrophages was associated with decreased overall survival and higher histologic grade. We observed macrophage-induced tumor cell proliferation in cocultures of human monocyte-derived macrophages and leiomyosarcoma (TYLMS-1) and myxofibrosarcoma (NMFH-1) cell lines, which was abrogated by silencing of CD163. Tumor development of sarcoma (MCA205 and LM8) cells in CD163-deficient mice was significantly abrogated in comparison with wild-type (WT) mice. Coculture with WT peritoneal macrophages significantly increased proliferation of MCA205 cells but decreased in the presence of CD163-deficient macrophages. Production of IL6 and CXCL2 in CD163-deficient macrophages was suppressed in comparison with WT macrophages, and overexpression of CD163 in CD163-deficient macrophages induced production of IL6 and CXCL2. Silencing of IL6 but not CXCL2 abrogated macrophage-induced proliferation of MCA205 cells. Taken together, our results show that CD163 is involved in protumoral activation of macrophages and subsequent development and progression of tumors in mice and humans.Significance: Macrophage CD163-mediated induction of IL6 promotes tumor development and progression in murine and human malignant tumors. Cancer Res; 78(12); 3255-66. ©2018 AACR.

Onionin A inhibits ovarian cancer progression by suppressing cancer cell proliferation and the protumour function of macrophages.

It is well known that tumour-associated macrophages (TAMs) play an important role in tumour development by modulating the tumour microenvironment, and targeting of protumour activation or the M2 polarization of TAMs is expected to be an effective therapy for cancer patients. We previously demonstrated that onionin A (ONA), a natural low molecular weight compound isolated from onions, has an inhibitory effect on M2 macrophage polarization. In the present study, we investigated whether ONA had a therapeutic anti-ovarian cancer effect using in vitro and in vivo studies. We found that ONA reduced the extent of ovarian cancer cell proliferation induced by co-culture with human macrophages. In addition, we also found that ONA directly suppressed cancer cell proliferation. A combinatorial effect with ONA and anti-cancer drugs was also observed. The activation of signal transducer and activator of transcription 3 (STAT3), which is involved in cell proliferation and chemo-resistance, was significantly abrogated by ONA in ovarian cancer cells. Furthermore, the administration of ONA suppressed cancer progression and prolonged the survival time in a murine ovarian cancer model under single and combined treatment conditions. Thus, ONA is considered useful for the additional treatment of patients with ovarian cancer owing to its suppression of the protumour activation of TAMs and direct cytotoxicity against cancer cells.

Onionin A, a sulfur-containing compound isolated from onions, impairs tumor development and lung metastasis by inhibiting the protumoral and immunosuppressive functions of myeloid cells.

SCOPE: Recent studies have demonstrated that myeloid lineage cells, such as macrophages and myeloid suppressor cells (MDSCs), are major components exhibiting protumoral functions in the setting of tumor progression. Tumor-associated macrophages polarized to the protumoral M2 phenotype promote tumor proliferation and are considered to be a therapeutic target in patients with malignant tumors. METHODS AND RESULTS: We identified a new candidate compound, called onionin A (ONA) isolated from onions, that inhibits macrophage polarization into the M2 phenotype, as well as the immunosuppressive activity of MDSCs and tumor proliferation, by suppressing signal transducer and activator of transcription-3 (Stat3) activation. Furthermore, ONA administration was found to significantly suppress subcutaneous tumor development and lung metastasis in tumor-bearing mice. ONA administration also inhibited Stat3 activation and increased the number of infiltrating lymphocytes in tumor tissues, and an ex vivo analysis showed that the immunosuppressive effect of MDSCs in tumor-bearing mice is impaired by ONA. Moreover, ONA regulated tumor proliferation by inhibiting cell-cell interactions between macrophages and tumor cells, and ONA administration enhanced the antitumor effects of cisplatin in the tumor-bearing mice. CONCLUSIONS: These findings demonstrate that ONA may be a potential new tool for antitumor therapy and also for tumor prevention.