Cervical Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Cervical Cancer, including details on symptoms, vaccine, screening, treatment, human papilloma virus (hpv), information.

Effects of human papillomavirus type 16 E7 protein on the growth of cervical carcinoma cells and immuno-escape through the TGF-beta1 signaling pathway.

Xu Q, Wang S, Xi L, Wu S, Chen G, Zhao Y, Wu Y, Ma D

Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical School, Huazhong University of Science and Technology, 1095 Jiefang Ave., Wuhan, Hubei 430030, P R China.

OBJECTIVE: E7 is regarded as one of the main oncoproteins of high-risk human papillomaviruses (HPVs). It may affect the transforming growth factor beta 1 (TGF-beta1) signaling pathway. In this study, the relationship between HPV-16 infection and the functions of three critical factors of the TGF-beta1/Smads pathway was explored to assess the possible role of E7 in the development of cervical cancer. METHODS: The expression of E7, TGF-beta1, TbetaR-II and Smad4 was detected by immunohistochemistry in paraffin-embedded cervical samples, and by RT-PCR and Western blotting in cervical cancer cell lines. The effect of TGF-beta1 on the growth of cervical cancer cells were tested by methyl thiazolyl tetrazolium (MTT), and the effects of HPV-16 E7 protein on normal and malignant cervical cells were investigated by flow cytometry. RESULTS: During the progression from benign to malignant lesions, the expression levels of TGF-beta1 and Smad4 increased significantly in cervical carcinoma tissues. The expression of TGF-beta1 was positively correlated with E7 expression. In vitro experiments showed that TGF-beta1 could not inhibit the proliferation of several cervical carcinoma cell lines in long-term regulation, but could inhibit immunologic reactions of peripheral blood mononuclear cells (PBMCs). Blocking E7 expression could lower the expression level of TGF-beta1 and induce cells to enter apoptosis. CONCLUSIONS: Our data indicate that HPV-16 E7 protein plays an important role during the development of cervical cancer by immuno-inhibition and stimulation of tumor cell proliferation through the TGF-beta1/Smads signaling pathway.

Published 28 February 2006 in Gynecol Oncol, 101(1): 132-9.
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