Human Papillomavirus 16/18 E6 Oncoprotein Is Expressed in Lung Cancer and Related with p53 Inactivation

Abstract

Inactivation of p53 by human papillomavirus 16/18 E6 plays a crucial role in cervical tumorigenesis. To investigate the involvement of HPV16/18 in lung tumorigenesis, the association between HPV16 or HPV18 E6 and p53 protein expression in 122 lung tumors was evaluated by immunohistochemistry, and data showed that HPV16/18 E6 expression correlated inversely with p53 expression, which was further confirmed by tissue in situ immunostaining. Real-time reverse transcription-PCR analysis indicated that E6-positive tumors had lower p21 WAF1/CIP1 and mdm2 mRNA levels than E6-negative tumors. To elucidate the role of E6 in p53 inactivation, we successfully established lung adenocarcinoma cell lines with or without HPV16 infection from patients' pleural effusions. Western blotting showed that E6 protein was indeed expressed in HPV16-infected cells and a lower level of p53 protein was observed in E6-positive cells compared with E6-negative cells. Moreover, the levels of p21 WAF1/CIP1 and mdm2 mRNA in E6-positive cells were lower than in E6-negative cells. The interaction of E6 with p53 protein was revealed by immunoprecipitation assay showing that p53 could be inactivated by E6 protein. Conversely, p53 proteins and p21 WAF1/CIP1 and mdm2 mRNA expressions were restored in E6-knockdown cells by RNA interference compared with control cells. These results reveal that HPV16/18 E6 may be partially involved in p53 inactivation to down-regulate p21 WAF1/CIP1 and mdm2 transcription. In conclusion, HPV16/18 E6 is indeed expressed in HPV DNA-positive lung tumors and is involved in p53 inactivation to contributing to HPV-mediated lung tumorigenesis. [Cancer Res 2007;67(22):10686-93]

miR-483-5p Promotes Invasion and Metastasis of Lung Adenocarcinoma by Targeting RhoGDI1 and ALCAM

“…The sequences of the probes (Exiqon) for hsa-miR-483-5p containing the locked nucleic acid/ digoxigenin-modified bases were as follows: CTCCCTTCT-TTCCTCCCGTCTT. Immunohistochemical staining for proteins was carried out as previously described (24,25). The intensity of miR-483-5p and proteins staining in epithelial cells of the 75 lung adenocarcinoma samples was scored using a semiquantitative scale as previously described (24,25).…”

“…Immunohistochemical staining for proteins was carried out as previously described (24,25). The intensity of miR-483-5p and proteins staining in epithelial cells of the 75 lung adenocarcinoma samples was scored using a semiquantitative scale as previously described (24,25). Shortly, immunostaining was defined as "high" if the immunoreactivity was observed in 10% or more of the cells in paraffin sections; tumors with lower percentages of immunoreactive cells showed "low" immunostaining.…”

A Polymorphic −844T/C in FasL Promoter Predicts Survival and Relapse in Non–Small Cell Lung Cancer

“…Tumor DNA was amplified and used for determining p53 mutation by direct sequencing with the Applied Biosystems 3100 Avant Genetic Analyzer, as described by Cheng and colleagues (32).…”

“…TL4 and TL13 lung cancer cells were established from pleural effusions as described previously (32). The pathologic diagnosis of TL13 was lung adenocarcinoma of a 79-year-old male nonsmoker with T 4 N 3 M 1 .…”

“…The shRNA contain 21 nucleotides from the FasL sequence as target site was AGGCCTGTGTCTCCTTGTGAT. The procedures and methods were as described previously (32).…”