| Summary: | 碩士 === 中山醫學大學 === 醫學分子毒理學研究所 === 98 === Basal cell carcinoma (BCC) is one of the most commonly skin cancer in humans and is characterized as locally aggressive slowly growing tumor with rarely metastatic potential. Skin exposed to sunlight is considered to be a major etiologic factor for the pathogenesis of BCC. In addition, either trauma scald or vaccine inoculation cause skin pathological change may increase the incidence.
Keratinocytes can be induced to produce cytokines by several exogenous stimuli and dysregulation of this production has been described in various skin diseases, including cancer. The release of these cytokines can trigger a cutaneous inflammatory. It has been demonstrated previously that UVB irradiation strongly upregulates IL-6 and IL-8 secretion in human keratinocytes immortalized with HPV-16 or HPV-38 and suggest an active role of these viruses in modulation of the skin inflammatory process.
Human papillomavirus (HPV) can be classified into high-risk or low-risk groups according to the propensity for malignant progression of the associated lesions which they cause. The high-risk types of HPV involved in carcinogenesis almost are HPV type 16 and 18. Lines of investigation indicate that the two oncoproteins E6 and E7 are known to inactivate the major tumor suppressors, p53 and retinoblastoma protein (pRB), respectively. In addition, it has conferred the tumourigenic properties of transformed cells by multiple mechanisms. The BCC-1/KMC cell line was derived from the facial BCC of a female patient on the thermal traumatic scar. In this study, we used BCC-1/KMC to demonstrate the role of HPV-18 infection on BCC cell.
First, we used western blot to demonstrate HPV-18 E6 and E7 are present in BCC-1/KMC cell line. To inhibit E6 and E7, the inducible-shRNA systems were designed and the coordinate inactivation of E6 and E7 as the target gene, are provided by the system that responds to the presence of the inducer doxycycline (Dox). We have demonstrated that p53 and Rb were upregulated by silencing HPV E6 and HPV E7. Furthermore, our data suggest that the regulation of E6 and E7 is an interrelated one but not independent function.
Next, we asked whether the HPV E6 and E7 play an important role to the production of cytokine during the tumourigenesis in BCC cells. We used semiquantitative RT-PCR to detect the altered expression of IL-6 and IL-8 by silencing HPV E6 and HPV E7. We also detected the effect of UVB irradiation on secretion of IL-6, IL-8 that involved in the inflammatory process by HPV-infected skin cancer cell. These results suggest that cytokines may synergistically cooperate in the development of skin lesions. Whether there are other cytokines involved in inflammation and the correlation to HPV E6/E7 is not clear. Therefore, we plan to investigate these issues in near future.
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