In:
Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 28, No. 3 ( 2022-02-01), p. 552-567
Abstract:
Immunotherapies targeting immune checkpoint molecules have shown promising treatment for a subset of cancers; however, many “cold” tumors, such as prostate cancer, remain unresponsive. We aimed to identify a potential targetable marker relevant to prostate cancer and develop novel immunotherapy. Experimental Design: Analysis of transcriptomic profiles at single-cell resolution was performed in clinical patients' samples, along with integrated analysis of multiple RNA-sequencing datasets. The antitumor activity of YY001, a novel EP4 antagonist, combined with anti–programmed cell death protein 1 (PD-1) antibody was evaluated both in vitro and in vivo. Results: We identified EP4 (PTGER4) as expressed in epithelial cells and various immune cells and involved in modulating the prostate cancer immune microenvironment. YY001, a novel EP4 antagonist, inhibited the differentiation, maturation, and immunosuppressive function of myeloid-derived suppressor cells (MDSC) while enhancing the proliferation and anticancer functions of T cells. Furthermore, it reversed the infiltration levels of MDSCs and T cells in the tumor microenvironment by overturning the chemokine profile of tumor cells in vitro and in vivo. The combined immunotherapy demonstrated a robust antitumor immune response as indicated by the robust accumulation and activation of CD8+ cytotoxic T cells, with a significantly decreased MDSC ratio and reduced MDSC immunosuppression function. Conclusions: Our study identified EP4 as a specific target for prostate cancer immunotherapy and demonstrated that YY001 inhibited the growth of prostate tumors by regulating the immune microenvironment and strongly synergized with anti–PD-1 antibodies to convert completely unresponsive prostate cancers into responsive cancers, resulting in marked tumor regression, long-term survival, and lasting immunologic memory.
Type of Medium:
Online Resource
ISSN:
1078-0432
,
1557-3265
DOI:
10.1158/1078-0432.CCR-21-0299
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2022
detail.hit.zdb_id:
1225457-5
detail.hit.zdb_id:
2036787-9
