Curcumin Regulates Autophagy, Lysosomal Degradation and Proliferation in Cervical Cancer Cells Infected with HPV16

Abstract

Objectives: To investigate the proliferation, autophagy and mechanism of curcumin in the treatment of cervical cancer cells complicated with human papillomavirus (HPV) infection. Methods: The C33A-E6 cell line which interfered with the human papillomavirus type 16-E6 (HPV16-E6) oncoprotein overexpression and small interfering RNA (siRNA) were constructed. The cell proliferation, oxidative stress injury, autophagy levels and lysosomal fluorescence intensity were compared by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) proliferation assay, reactive oxygen species (ROS) assay, and real-time polymerase chain reaction (RT-PCR) assay as well as lysosomal labeling assay. Results: The interference efficiency of HPV16-E6 was significant. Compared with the negative cells, the growth rate of SiHA-E6-Si cells increased faster. The fluorescence interval of HPV16 E6 positive cells was significantly increased compared with that of negative cells. Induction of autophagy did not affect SIHA-E6-Si cell proliferation. The expression levels of Beclin-1, light chain 3-II (LC3-II), and dynactin 4 (P62) in HPV-positive cells were significantly increased compared with those in negative cells. Moreover, the expression of Beclin-1, LC3-II, and P62 increased significantly after autophagy induction. In addition, the fluorescence intensity of lysosomes decreased after autophagy induction. The content of ROS did not change significantly after autophagy induction. Conclusions: Curcumin regulates the expression of autophagy-related proteins (Beclin-1, LC3-II, and P62) in cervical cancer cells with HPV16 persistent infection.