Infiltrating CD4+ T cells attenuate chemotherapy sensitivity in prostate cancer via CCL5 signaling. Issue 9 (24th April 2019)

• Record Type: Journal Article
• Authors: Xiang, Peng; Jin, Song; Yang, Yang; Sheng, Jindong; He, Qun; Song, Yi; Yu, Wei; Hu, Shuai; Jin, Jie
• Is Part Of: Prostate. Volume 79:Issue 9(2019)
• Page Start: 1018
• Page End: 1031
• Publication Date: 2019-04-24
• Subjects: C‐C motif chemokine ligand 5 signaling -- CD4+ T cells -- chemotherapy resistance -- PCa; Prostate -- Diseases -- Periodicals; 616
• DOI: 10.1002/pros.23810
• Languages: English
• ISSNs: 0270-4137

Abstract

Abstract: Background: Chemotherapy with Docetaxel (Doc) is efficient in a subset of prostate cancer (PCa) cases; however, most patients ultimately develop resistance to Docetaxel. The tumor immune microenvironment and secreted cytokines play a substantial role in development of resistance to chemotherapy. Our previous study has demonstrated that CD4+ T cells in prostate tumor microenvironment contribute to PCa progression; meanwhile, we found increased CD4+ T‐cell infiltration in tumor area after Doc treatment; however, their effects on PCa chemosensitivity remain unclear. Here, we aim to explore the role and mechanisms of CD4+ T cells in PCa chemotherapy sensitivity. Methods: CD4+ T‐cell infiltration in Doc‐treated paraffin‐embedded specimens from transurethral resection of prostate, radical prostatectomy, or bone metastasis was detected by immunohistochemistry. The castration‐resistant PCa cell lines—C4‐2 and CWR22RV1, and CD4+ T‐cell lines—HH and Molt‐3 were used in the coculture system. After coculture with the lymphocytes, PCa cell chemosensitivity was detected by cell counting kit‐8, terminal deoxynucleotidyl transferase dUTP nick‐end labeling assays, and Western blot analysis. Various cell cytokines were determined by cytokine arrays and reverse‐transcription polymerase chain reaction. The recombinant human C‐C motif chemokine ligand 5 (CCL5) was added to PCa cells for further confirming its effects and anti‐CCL5 antibody was used for neutralization. S3I‐201, a signal transducer and activator of transcription 3 (STAT3) inhibitor, was added to the coculture system to detect STAT3 role in chemosensitivity. Tumor xenografts in nude mice were used for confirming effects of CD4+ T cells in vivo study. Results: We found more infiltrated CD4+ T cells in human PCa lesions than in the adjacent noncancerous tissues after Doc treatment. In vitro cell line study confirmed that CD4+ T cells increase the PCa Doc resistance. Quantative polymerase chain reaction and cytokine arrays indicated that after coculture with PCa, CD4+ T cells could secrete large amounts of CCL5. Moreover, CCL5 stimulation enhanced PCa resistance to Doc, and anti‐CCL5 antibody could partly reverse this process. We found that CD4+ T cells could activate P‐STAT3 signaling via secreting CCL5 and adding a STAT3 inhibitor can reverse the chemoresistance. In vivo mouse model with xenografted 22RV1 cells and CD4+ T cells also confirmed the in vitro results. Conclusions: Together, our results indicate that infiltrating CD4+ T cells could promote PCa chemotherapy resistance via modulation of the CCL5/STAT3 signaling pathway.