Journal of Translational Medicine // Published: 29 July 2015 // © 2015 Guo et al.
Zhiqiang Guo1*, Haolin Wang2, Fandong Meng3, Jie Li1 and Shulan Zhang1 .
Abstract
Monoclonal antibodies (mAb) that block programmed death (PD)-1 signaling pathway hold great potential as a novel cancer immunotherapy. Recent evidence suggests that combining with conventional, targeted or other immunotherapies, these mAb can induce synergistic antitumor responses. In this study, we investigated whether Trabectedin (ET-743), a novel anticancer agent currently used for treating relapsed ovarian cancer, can synergize with anti (α)-PD-1 mAb to increase antitumor activity in the murine ID8 ovarian cancer model.
Methods
Mice with established peritoneal ID8 tumor were treated with either single or combined Trabectedin and α-PD-1 mAb, their overall survival was recorded; tumor-associated immune cells and immune gene expression in tumors from treated mice were analyzed by flow cytometry and quantitative RT-PCR, respectively, and antigen-specific immunity of effector CD8 + T cells was evaluated by ELISA and cytotoxicity assay. In addition, the effect of Trabectedin on tumoral PD-L1 expression was analyzed by both flow cytometry and immunofluorescence staining.
Results
Though single treatment showed a modest antitumor effect in mice bearing 10-day-established ID8 tumor, combined Trabectedin and α-PD-1 mAb treatment induced a strong antitumor immune response, leading to a significant tumor regression with half of mice tumor-free 90 days after tumor inoculation. Mechanistic investigation revealed that combination treatment induces a systemic tumor-specific immunity with an indispensable role of both CD4 + and CD8 + T cells, and effector CD8 + T cells exhibited the antigen-specific cytokine secretion and cytotoxicity upon tumor antigen stimulation; additionally, combination treatment increased the IFN-γ-producing effector T cells and decreased the immunosuppressive cells in peritoneal cavity; accordingly, it enhanced the expression of Th1-associated immune-stimulating genes while reducing the transcription of regulatory/suppressive immune genes, reshaping tumor microenvironment from a immunosuppressive to a stimulatory state. Finally, in vivo Trabectedin treatment has been shown to induce IFN-γ-dependent PD-L1 expression within tumor, possibly constituting a mechanistic basis for its synergistic antitumor effect with α-PD-1 mAb therapy.
Conclusion
This study provides the evidence that α-PD-1 mAb can produce a synergistic antitumor efficacy when combined with Trabectedin, a clinically available anticancer agent, supporting a direct translation of this combination strategy in clinic for the treatment of ovarian cancer.
P.J. : Datos que demuestran la actividad específica de 'Yondelis' sobre el microambiente tumoral, concretamente reduciendo los macrófagos asociados al tumor.
Así, además de inducir la muerte de las células tumorales, 'Yondelis' actúa deplecionando los macrófagos asociados al tumor. Estas células, que normalmente forman parte del sistema inmunológico, tienen en el tumor una actividad protumoral ya que liberan una serie de factores que estimulan la división de las células tumorales así como la formación de neovasos.
Al inducir la muerte de éstas células, 'Yondelis' inhibe esta actividad protumoral y disminuye la secreción de los factores estimulantes del crecimiento tumoral. Este mecanismo de acción es particular a 'Yondelis' y no se observa con ninguna de los otros agentes antitumorales estudiados.
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July 2015
Bonavita E1, Galdiero MR2, Jaillon S1, Mantovani A3.
Author information1IRCCS Istituto Clinico Humanitas, Rozzano, Italy.2IRCCS Istituto Clinico Humanitas, Rozzano, Italy; Division of Clinical Immunology and Allergy, University of Naples Federico II, Naples, Italy.3IRCCS Istituto Clinico Humanitas, Rozzano, Italy; Humanits University, Rozzano, Italy.
Abstract :
Inflammation is a key component of the tumor microenvironment. Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) are prototypic inflammatory cells in cancer-related inflammation. Macrophages provide a first line of resistance against infectious agents but in the ecological niche of cancer behave as corrupted policemen. TAMs promote tumor growth and metastasis by direct interactions with cancer cells, including cancer stem cells, as well as by promoting angiogenesis and tissue remodeling and suppressing effective adaptive immunity. In addition, the efficacy of chemotherapy, radiotherapy, and checkpoint blockade inhibitors is profoundly affected by regulation of TAMs. In particular, TAMs can protect and rescue tumor cells from cytotoxic therapy by orchestrating a misguided tissue repair response. Following extensive preclinical studies, there is now proof of concept that targeting tumor-promoting macrophages by diverse strategies (e.g., Trabectedin, anti-colony-stimulating factor-1 receptor antibodies) can result in antitumor activity in human cancer and further studies are ongoing. Neutrophils have long been overlooked as a minor component of the tumor microenvironment, but there is evidence for an important role of TANs in tumor progression. Targeting phagocytes (TAMs and TANs) as corrupted policemen in cancer may pave the way to innovative therapeutic strategies complementing cytoreductive therapies and immunotherapy
