[Regulation of human papillomavirus (HPV) genome replication in the viral life cycle and its association with the viral persistence and cancer development]

Effect of 5-aminolevulinic acid photodynamic therapy on the expression of apoptosis inhibitors Bcl-2 and Survivin in keratinocytes of condyloma acuminatum

BACKGROUND

Condyloma acuminatum is a highly infectious disease caused by the human papillomavirus. Previous studies have shown that 5-aminolevulinic acid photodynamic therapy can inhibit proliferation of condyloma acuminatum keratinocytes. However, the effect of 5-aminolevulinic acid photodynamic therapy on condyloma acuminatum tissues has not been systematically studied. Here, we investigated possible molecular mechanisms of 5-aminolevulinic acid photodynamic therapy in the treatment of condyloma acuminatum and its effect on the expression of apoptosis inhibitors Bcl-2 and Survivin.

METHODS

Immunohistochemistry streptavidin-peroxidase was used to detect the expression of apoptosis inhibitors Bcl-2 and Survivin in condyloma acuminatum keratinocytes before and after the therapy.

RESULTS

The positive expression rates of Bcl-2 and Survivin in condyloma acuminatum keratinocytes before treatment were 87.50% (42/48) and 79.16% (38/48), respectively. The positive expression rates of Bcl-2 and Survivin in condyloma acuminatum keratinocytes after treatment were 37.50% (18/48) and 41.67% (20/48), respectively. The positive expression intensity of Bcl-2 and Survivin in condyloma acuminatum keratinocytes before 5-aminolevulinic acid photodynamic therapy was mostly ++ to +++, and that after treatment was mostly - to +. There were statistically significant differences in the positive expression rate and the expression intensity of Bcl-2 and Survivin in the two groups before and after 5-aminolevulinic acid photodynamic therapy (P <  0.001). There was a positive correlation between the expression of Bcl-2 and Survivin in condyloma acuminatum tissues after 5-aminolevulinic acid photodynamic therapy (r = 0.480, P <  0.05).

CONCLUSION

5-aminolevulinic acid photodynamic therapy may promote apoptosis of condyloma acuminatum cells by reducing the expression of Bcl-2 and Survivin, suggesting that this is potentially one of the molecular mechanisms of 5-aminolevulinic acid photodynamic therapy in the treatment of condyloma acuminatum.

Interplay between NF-κB/interferon signaling and the genome replication of HPV

HPV infection can persist within the infected epithelium for years. The viral persistence is primarily attributed to the ability of the virus to maintain its genome as nuclear episomes in the basal cells. Recent studies have revealed that HPV induces DNA damage response to facilitate productive amplification of the viral genome. DNA damage response comprises a part of the cellular defense mechanism against viral infection and its activation can result in induction of innate immune responses. The activation of NF-κB and interferon (IFN) signals has been shown to suppress the genome replication of HPV while the viral proteins inhibit NF-κB/IFN signaling. This review intends to focus on illustrating the interplay between NFκB/IFN signaling and HPV genome replication in the HPV life cycle.