Expression of caveolin-1 in keratinocytes and its correlation with cellular proliferation and apoptosis in condyloma acuminatum skin lesions

Abstract

Objective To investigate the expression of caveolin-1 in keratinocytes of condylomata acuminatum(CA)skin lesions, and to explore its correlation with keratinocyte proliferation and apoptosis. Methods Tissue specimens were obtained from lesions of 40 patients with CA (CA group)and normal skin of 10 healthy human controls(control group), then fixed with formalin and embedded with paraffin. An immunohistochemical analysis was done using the EnVision system to measure the expressions of caveolin-1 (expressed as absorbance value)and proliferating cell nuclear antigen (PCNA)in keratinocytes, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to evaluate apoptosis of keratinocytes in these tissue specimens. The proliferative index and apoptotic index of cells were calculated. Independent samples t test was conducted to compare these parameters between the two groups, and Pearson correlation analysis to assess the relationship of caveolin-1 expression with proliferative index and apoptotic index. Three small interfering RNAs (siRNAs)were designed targeting the caveolin-1 gene, and transfected into HaCaT cells separately by using liposomes. Then, fluorescence-based quantitative PCR (qPCR)was performed to detect the expression of caveolin-1, so as to find the most efficient siRNA. Cultured HaCaT cells were divided into 3 groups: experimental group transfected with caveolin-1 siRNA, negative control group transfected with nonspecific siRNA, and blank control group receiving no treatment. Western blot analysis and immunofluorescence assay were carried out to quantify the protein expression of caveolin-1 in HaCaT cells at 48 hours after transfection, MTS assay was performed to evaluate proliferative activity of HaCaT cells at 24, 48 and 72 hours, and flow cytometry (FCM)to detect cell apoptosis at 48 hours. Results Compared with the control group, the CA group showed significantly decreased caveolin-1 expression (0.042±0.021 vs. 0.181±0.075, t = 5.843, P 0.05). Conclusion The expression of caveolin-1 is decreased in keratinocytes of CA skin lesions, which may be associated with accelerated proliferation and decreased apoptosis of keratinocytes. Key words: Condylomata acuminata; Caveolin 1; Keratinocytes; Apoptosis; Cell proliferation