AUTHOR=Pu Dan , Yin Liyuan , Huang Lin , Qin Changlong , Zhou Yuwen , Wu Qiang , Li Yan , Zhou Qinghua , Li Lu 

TITLE=Cyclooxygenase-2 Inhibitor: A Potential Combination Strategy With Immunotherapy in Cancer

JOURNAL=Frontiers in Oncology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.637504

DOI=10.3389/fonc.2021.637504

ISSN=2234-943X

ABSTRACT=<p>The clinical application of immunotherapy is the milestone of cancer treatment. However, some patients have bad reaction. Cyclooxygenase-2 (COX-2) is frequently expressed in multiple cancer cells and is associated with poor prognosis. It is the key enzyme of prostaglandin E<sub>2</sub> (PGE2) that has been proved to promote the development, proliferation and metastasis of tumor cells. Recent studies further find the PGE2 in tumor microenvironment (TME) actively triggers tumor immune evasion <italic>via</italic> many ways, leading to poor response of immunotherapy. COX-2 inhibitor is suggested to restrain the immunosuppression of PGE2 and may enhance or reverse the response of immune checkpoint inhibitors (ICIs). This review provides insight into the mechanism of COX-2/PGE2 signal in immunosuppressive TME and summarizes the clinical application and trials in cancer treatment.</p>