Objective: to the explore the effect of Human papillomavirus (HPV) 16 peptide vaccine in combination with paclitaxel-cisplatin (TP) chemotherapy on cervical cancer in vitro and in vivo.
Methods: (1) the major histocompatibility complex (MHC) class I restricted T cell epitopes were studied by bioinformatics for transporter associated with antigen processing (TAP). Their effects were compared and E7Pa had the most dramatic effect. (2) In vivo, the C57BL/6 mice were divided equally into 6 groups randomly after loading with TC-1 cells (HPV 16 positive tumor cells from C57BL/6 mouse), named as E7Pa + CpG + TP, E7Pa + CpG, CpG + TP, TP and CpG group as experiment groups and control (blank injection with physiological saline). The tumor volumes were measured regularly by tumor growth curve to compare the therapeutic effects in different groups; the related cell factors in murine peripheral blood were evaluated by enzyme-linked immunosorbent assay (ELISA); the TUNEL test kit was used to explore cellular apoptosis in tumor tissue; the survival curve was drawn from the TC-1 cell loading to natural death; safety was tested by pathological test and leucocyte count.
Results: at day 60 of tumor growth, the tumor volume of immunotherapy plus TP chemotherapy group was (0.013 ± 0.010) cm(3) versus the control (1.900 ± 0.075) cm(3) with a great significant deviation (P < 0.01). Meanwhile, the volumes were E7Pa + CpG group (0.340 ± 0.038) cm(3), TP + CpG group (0.650 ± 0.029) cm(3), TP group (1.100 ± 0.052) cm(3) and that of CpG group was (0.890 ± 0.047) cm(3) separately. And these groups had significant difference with the controls (P < 0.05). The average survival time of different groups were E7Pa + CpG + TP group (108.50 ± 8.97) d, E7Pa + CpG group (100.02 ± 2.27) d, CpG + TP group (79.63 ± 4.05) d, TP group (73.24 ± 3.11) d, CpG group (68.63 ± 1.38) d and controls (52.37 ± 2.47) d. And the difference between the E7Pa + CpG + TP and E7Pa + CpG groups had great significance with the controls (P < 0.01). Furthermore, the immune system was effectively stimulated for suppressing tumor growth in the immunotherapy group while cell apoptosis was significantly induced in the chemotherapy group. The combination of immunotherapy and chemotherapy was significantly efficacious than either of them alone. And it could thoroughly stimulate the immune effects and enhance the anti-tumor function of chemotherapeutical drugs. In safety test, there was no significant difference among all groups.
Conclusion: the HPV16 peptide vaccine in combination with TP chemotherapy can treat the HPV16 E7 positive tumor effectively in experiment.