Human papillomavirus type 16 E6 suppresses microRNA-23b expression in human cervical cancer cells through DNA methylation of the host gene C9orf3.

Oncogenic protein E6 of human papillomavirus type 16 (HPV-16) is believed to involve in the aberrant methylation in cervical cancer as it upregulates DNA methyltransferase 1 (DNMT1) through tumor suppressor p53. In addition, DNA demethylating agent induces the expression of one of the HPV-16 E6 regulated microRNAs (miRs), miR-23b, in human cervical carcinoma SiHa cells. Thus, the importance of DNA methylation and miR-23b in HPV-16 E6 associated cervical cancer development is investigated.

P-glycoprotein enhances radiation-induced apoptotic cell death through the regulation of miR-16 and Bcl-2 expressions in hepatocellular carcinoma cells.

P-glycoprotein (Pgp), an efflux pump, was confirmed the first time to regulate the expressions of miR/gene in cells. Pgp is known to be associated with multidrug resistance. RHepG2 cells, the multidrug resistant subline of human hepatocellular carcinoma HepG2 cells, expressed higher levels of Pgp as well as miR-16, and lower level of Bcl-2 than the parental cells.

HPV-16 E6 upregulation of DNMT1 through repression of tumor suppressor p53.

The HPV-16 early proteins E6 and E7 are considered to function as oncoproteins in cervical cancer. DNA methyltransferase 1 (DNMT1) is one of the enzymes involved in epigenetic silencing of tumor suppressor genes. In the present study, the functional role and regulation of DNMT1 in HPV-16 E6 associated cervical cancer development were examined.

AF1q enhancement of gamma irradiation-induced apoptosis by up-regulation of BAD expression via NF-kappaB in human squamous carcinoma A431 cells.

BAD (BCL-2 antagonist of cell death) is a pro-apoptotic BCL-2 family protein that plays a critical role in the regulation of apoptotic response. This study presents direct evidence that AF1q increased the radiation-induced apoptosis through up-regulation of BAD in human squamous carcinoma A431 cells and the key transcription factor involved is NF-kappaB. The minimal promoter sequence of BAD was identified; the activity was increased in AF1q stable transfectants and decreased upon AF1q siRNA transfection.