Human papillomavirus 16 variant E7 gene induces transformation of NIH 3T3 cells via up-regulation of cdc25A and cyclin A

Identification of pivotal cellular factors involved in HPV-induced dysplastic and neoplastic cervical pathologies

Cervical carcinoma represents the paradigm of virus-induced cancers, where virtually all cervical cancers come from previous "high-risk" HPV infection. The persistent expression of the HPV viral oncoproteins E6 and E7 is responsible for the reprogramming of fundamental cellular functions in the host cell, thus generating a noticeable, yet only partially explored, imbalance in protein molecular networks and cell signaling pathways. Eighty-eight cellular factors, identified as HPV direct or surrogate targets, were chosen and monitored in a retrospective analysis for their mRNA expression in HPV-induced cervical lesions, from dysplasia to cancer. Real-time quantitative PCR (qPCR) was performed by using formalin-fixed, paraffin embedded archival samples. Gene expression analysis identified 40 genes significantly modulated in LSIL, HSIL, and squamous cervical carcinoma. Interestingly, among these, the expression level of a panel of four genes, TOP2A, CTNNB1, PFKM, and GSN, was able to distinguish between normal tissues and cervical carcinomas. Immunohistochemistry was also done to assess protein expression of two genes among those up-regulated during the transition between dysplasia and carcinoma, namely E2F1 and CDC25A, and their correlation with clinical parameters. Besides the possibility of significantly enhancing the use of some of these factors in diagnostic or prognostic procedures, these data clearly outline specific pathways, and thus key biological processes, altered in cervical dysplasia and carcinoma. Deeper insight on how these molecular mechanisms work may help widen the spectrum of novel innovative approaches to these virus-induced cell pathologies.

Digalloylresveratrol, a novel resveratrol analog inhibits the growth of human pancreatic cancer cells

Digalloylresveratrol (DIG) is a recently synthesized substance aimed to combine the effects of the natural polyphenolic compounds gallic acid and resveratrol, which both are excellent free radical scavengers with anticancer activity. In this study, we investigated the effects of DIG in the human AsPC-1 and BxPC-3 pancreatic adenocarcinoma cell lines. Treatment with DIG dose-dependently attenuated cells in the S phase of the cell cycle and led to a significant depletion of the dATP pool in AsPC-1 cells. The incorporation of (14)C-cytidine into nascent DNA of tumor cells was significantly inhibited at all DIG concentrations due to inhibition of ribonucleotide reductase, a key enzyme of DNA synthesis in tumor cells. Furthermore, Erk1/2 became inactivated and moderated p38 phosphorylation reflecting increased replication stress. DIG also activated ATM and Chk2, and induced the phosphorylation and proteasomal degradation of the proto-oncogene Cdc25A, which contributed to cell cycle attenuation. Taken together, DIG is an excellent free radical scavenger, strongly inhibits RR in situ activity, cell cycle progression, and colony formation in AsPC-1 and BxPC-3 cells thus warranting further investigations.