Immune-checkpoint blockade (ICB) demonstrated inspiring effect and great promise in anti-cancer therapy. However, many obstacles, such as drug resistance and difficulty in patient selection, limited the efficacy of ICB therapy and awaited to be overcome. By timely identification and intervention of the key immune-suppressive promotors in the tumor microenvironment (TME), we may better understand the mechanisms of cancer immune-escape and use novel strategies to enhance the therapeutic effect of ICB. Myeloid-derived suppressor cell (MDSC) is recognized as a major immune suppressor in the TME. In this review, we summarized the roles MDSC played in the cancer context, focusing on its negative biologic functions in ICB therapy, discussed the strategies targeted on MDSC to optimize the diagnosis and therapy process of ICB and improve the efficacy of ICB therapy against malignancies.

Numerous evidences have shown that circular RNAs (circRNAs) play a key role in regulating the pathogenesis of cancer. However, the mechanism of circRNAs in urothelial carcinoma of bladder (UCB) remains largely unclear. In this study, we found circFAM114A2 was significantly downregulated both in UCB tissue specimens and cell lines, and the expression level was highly correlated with pathological TNM stage and grade. Functionally, overexpression of circFAM114A2 dramatically inhibited the migration, invasion and proliferation of UCB cells in vitro, and suppressed tumor growth in vivo. Mechanistically, we confirmed miR-762 was copiously pulled down by circFAM114A2 in 5637 and T24 cells. Fluorescence in situ hybridization (FISH) further indicated the cytoplasmic interactions between circFAM114A2 and miR-762. By using luciferase reporter assay, we found that miR-762 could directly target TP63. Subsequently, we found that circFAM114A2 might increase the expression of ΔNP63 (main isoform of TP63 in UCB) by sponging miR-762. Taken together, our results demonstrated that circFAM114A2 might serve as a competing endogenous RNA (ceRNA) of miR-762 in regulating the expression of ΔNP63, thus suppressed UCB progression through circFAM114A2/miR-762/ΔNP63 axis.

Introduction: Although immunotherapy works well in parts of patients with bladder cancer (BLCA), its overall response rate of anti-PD-1 inhibitors remains unsatisfactory. Besides, growing evidence shows that tumor-infiltrating lymphocytes (TILs) immunotherapy has demonstrated excellent efficacy in various cancers. Considering the huge heterogeneity and low overall survival rate of BLCA, it is urgent to explore the new immune checkpoints (ICs) or TILs therapy to improve the survival prognosis for BLCA patients. Materials and Methods: The public bioinformatics databases were used to explore the prognostic value of 5 potential ICs targets (TIM-3, LAG-3, OX40, 4-1BB and CD39). A total of 46 BLCA patients undergoing surgical treatment at our hospital from May 2020 to October 2020 were enrolled in this study. The expressions of PD-1, TIM-3, LAG-3, OX40, 4-1BB, and CD39 in T cells of BLCA patients were explored by flow cytometry, and the correlation between different subgroups of T cells and clinicopathological parameters was analyzed. Besides, the mouse CD4+CD39+ T cells, CD4+CD39-T cells, CD8+CD39+ T cells, and CD8+CD39-T cells were sorted and co-cultured with MB49 bladder cancer cell lines in vitro to investigate the potential biomarker of tumor-reactive TILs. Results: Public bioinformatics databases analyses show that only the high expression of CD39 was significantly associated with advanced tumor stage (P < 0.001) and tend to result in a worse survival rate. In our study, the elevated expression of CD39 in CD4+/CD8+ T cells were significantly associated with the pathological T stage (pT <2, P = 0.041) and papillary tumor (P = 0.038). Moreover, the CD8+CD39+ T cells showed a stronger tumorkilling effect and produced a higher level of IFN-γ than other T cell populations. Conclusion: CD39 may be a potential prognostic marker in BLCA, and CD8+CD39+ T cells may be selected as tumor-reactive and killing T cells for TILs therapy.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.