[Expression of angiotensin II type 1 receptor in cervical squamous cell carcinoma and its clinical significance].

Objective: To investigate the expression of Angiotensin II type 1 receptor (AT1R) in tissue and cell lines of squamous cervical carcinomas and its clinical significance, and to explore the molecular mechamisms of angiotensin II and AT1R activity in the process of cervical carcinogenesis.
Methods: (1) The levels of AT1R mRNA were examined by quantitative reverse transcriptase-polymerase chain reaction( RT-PCR) in paraffin-embedded tissues from 35 cases of cervical squamous cell carcinoma, 15 cases of cervical intraepithelial neoplasia (CIN), and 15 cases of normal cervix, and in Siha and C33a cells. The expression of AT1R protein in 65 specimens of cervix tissue sections was evaluated by immunohistochemistry. The corelation between the expressions of AT1R and its clinicopathologic features was analyzed accordingly. (2) After the Siha and C33a cells were treated at different concentrations of Angiotensin II (0, 10(-10) mol/L, 10(-9) mol/L, 10(-8) mol/L, 10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L) for different time in culture, the cell proliferation was determined by methylthiazolyl tetrazolium (MTT) assay. The vascular endothelial growth factor (VEGF) expression was examined by enzyme-linked immuno-absordent assay (ELISA).
Results: (1) AT1R mRNA expression was detected in the two cervix cancer cell lines. The positive rate of ATIR mRNA was 77.1%, 40.0% and 0, respectively, in squamous cell carcinomas, cervical intraepithelial neoplasia and normal cervical tissues, while their mRNA quantities were 0.3863 +/- 0.041, 0.0768 +/- 0.035 and 0, respectively. There was statistically a significant difference between them (P < 0.01). The average staining intensity of AT1R protein was stronger in invasive carcinoma cells than that in dysplasia tissues and normal ones (P < 0.01). Among 65 cases of squamous cell carcinomas, the expressions of AT1R mRNA and protein increased with pathological grading (P < 0.05), while it was neither correlated with clinical stage nor pelvic lymph node metastasis (P > 0.05). The level of AT1R protein expression corresponded to that of its mRNA. (2) Angiotensin II promoted the cell growth of cervical cancer cell lines Siha and C33a and induced secretion of VEGF from cells in a dose-dependent manner (P < 0.01), and the expression of VEGF was reversed by the addition of valsatan (an antagonist of angiotensin II type 1 receptor) (P < 0.01).
Conclusion: Angiotensin II is involved in the progression of cervical carcinoma, since it may increase the proliferation activity of cancer cells, induce secretion of VEGF through AT1R synchronously, and results in an increase of angiogenesis in tumors. It suggests that use of AT1R antagonists may be an useful therapeutic strategy for cervical carcinoma.