Peripheral blood mononuclear cells inhibit proliferation and promote apoptosis of HeLa cells following stimulation with Bacillus Calmette-Guerin
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- Published online on: December 10, 2012 https://doi.org/10.3892/etm.2012.855
- Pages: 561-566
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Abstract
Bacillus Calmette-Guerin (BCG) immunotherapy is established as an effective adjuvant intravesical treatment for non-muscle invasive bladder cancer. BCG is also effective in the treatment of Condylomata acuminata caused by low‑risk human papilloma virus (HPV). The aim of this study was to determine the efficacy of BCG for the treatment of cervical cancer or HPV high‑risk infections. BCG-activated killer (BAK) cells were incubated with a high‑risk HPV18-infected cervical cancer cell line, HeLa. The cell cycle distribution and apoptotic index of the HeLa cells were analyzed by flow cytometry. The alterations of HPV-E7, retinoblastoma (RB) and E2F1 levels were detected at the transcriptional and translational levels. The BAK cell cytotoxicity to HeLa cells was 24.08, 14.74 and 6.8% and the natural killer (NK) cell cytotoxicity was 17.62, 10.78 and 5.8% at the E/T ratios of 40:1, 20:1 and 10:1, respectively. The BAK cells significantly induced the apoptosis of HeLa cells to result in an apoptosis level of 24.2% compared with 13.45% by the NK cell treatment at the ratio of 20:1. BAK cells inhibit the proliferation of HeLa cells by G1/S cell cycle arrest and this may be associated with the RB/E2F1 pathway. However, G1/S arrest and the alteration of RB protein (pRB) and E2F1 levels in the HeLa cells did not show significant differences between the BAK cell‑ and NK cell-treated groups. HPV-E7 appeared not to be associated with the alteration in cell cycle progression. This study showed that immunotherapy may be a potential treatment for cervical cancer and that BCG immunotherapy may be an alternative and effective method, but further experiments and clinical trials are required to verify this effect.
