Effect of EBI3 on radiation-induced immunosuppression of cervical cancer HeLa cells by regulating Treg cells through PD-1/PD-L1 pathway

• Published in: Tumor biology 2017-03, Vol.39 (3), p.1010428317692237-1010428317692237
• Main Authors: Zhang, Song-An, Niyazi, Hu-Er-Xi-Dan, Hong, Wen, Tuluwengjiang, Gu-Li-Xian, Zhang, Lei, Zhang, Yang, Su, Wei-Peng, Bao, Yong-Xing
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; B7-H1 Antigen - biosynthesis; B7-H1 Antigen - genetics; Blood; Cancer therapies; CD4 antigen; CD8 antigen; Cell cycle; Cell proliferation; Cell Proliferation - radiation effects; Cervical cancer; Cervix; Enzymes; Female; Flow cytometry; Gene Expression Regulation, Neoplastic - radiation effects; HeLa Cells; Humans; Immunoglobulins; Immunology; Immunophenotyping; Immunosuppression; Infections; Interleukins - biosynthesis; Interleukins - genetics; Kinases; L1 protein; Laboratories; Lymphocytes; Lymphocytes T; Medical prognosis; Minor Histocompatibility Antigens - biosynthesis; Minor Histocompatibility Antigens - genetics; Neoplasms, Experimental - genetics; Neoplasms, Experimental - immunology; Neoplasms, Experimental - pathology; Neoplasms, Experimental - radiotherapy; Optical density; Overexpression; PD-1 protein; PD-L1 protein; Peroxidase; Phosphorylation; Programmed Cell Death 1 Receptor - biosynthesis; Programmed Cell Death 1 Receptor - genetics; Radiation therapy; Rats; Signal transduction; Signal Transduction - genetics; Signal Transduction - immunology; Signal Transduction - radiation effects; Streptavidin; T cell receptors; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - radiation effects; Uterine Cervical Neoplasms - genetics; Uterine Cervical Neoplasms - immunology; Uterine Cervical Neoplasms - pathology; Uterine Cervical Neoplasms - radiotherapy; Western blotting
• ISSN: 1010-4283; 1423-0380
• DOI: 10.1177/1010428317692237

This study aimed to investigate the effect of EBI3 on radiation-induced immunosuppression of cervical cancer HeLa cells by regulating Treg cells through PD-1/PD-L1 signaling pathway. A total of 43 adult female Wistar rats were selected and injected with HeLa cells in the caudal vein to construct a rat model of cervical cancer. All model rats were randomly divided into the radiotherapy group (n = 31) and the control group (n = 12). The immunophenotype of Treg cells was detected by the flow cytometry. The protein expressions of EBI3, PD-1, and PD-L1 in cervical cancer tissues were tested by the streptavidin–peroxidase method. HeLa cells in the logarithmic growth phase were divided into four groups: the blank, the negative control group, the EBI3 mimics group, and the EBI3 inhibitors group. Western blotting was used to detect PD-1 and PD-L1 protein expressions. MTT assay was performed to measure the proliferation of Treg cells. Flow cytometry was used to detect cell cycle and apoptosis, and CD4+/CD8+ T cell ratio in each group. Compared with before and 1 week after radiotherapy, the percentages of CD4+T cells and CD8+T cells were significantly decreased in the radiotherapy group at 1 month after radiotherapy. Furthermore, down-regulation of EBI3 and up-regulation of PD-1 and PD-L1 were observed in cervical cancer tissues at 1 month after radiotherapy. In comparison to the blank and negative control groups, increased expression of EBI3 and decreased expressions of PD-1 and PD-L1 were found in the EBI3 mimics group. However, the EBI3 inhibitors group had a lower expression of EBI3 and higher expressions of PD-1 and PD-L1 than those in the blank and negative control groups. The EBI3 mimics group showed an increase in the optical density value (0.43 ± 0.05), while a decrease in the optical density value (0.31 ± 0.02) was found in the EBI3 inhibitors group. Moreover, compared with the blank and negative control groups, the apoptosis rates of Treg/CD4+T/CD8+T cells were decreased in the EBI3 mimics group, but the EBI3 inhibitors group exhibited an increase in apoptosis rate. In conclusion, over-expression of EBI3 could reduce the apoptosis of Treg/CD4+T/CD8+T cells and prevent radiation-induced immunosuppression of cervical cancer HeLa cells by inhibiting the activation of PD-1/PD-L1 signaling pathway.