Cervical keratinocytes containing stably replicating extrachromosomal HPV-16 are refractory to transformation by oncogenic H-Ras

AbstractRas expression in human epithelial cells with integrated HPV genomes has been shown to cause tumorigenic transformation. The effects of Ras in cells representing early stage HPV-associated disease (i.e., when HPV is extrachromosomal and the oncogenes are under control of native promoters) have not been examined. Here, we used human cervical keratinocyte cell lines containing stably replicating extrachromosomal HPV-16 and present the novel finding that these cells resist transformation by oncogenic H-Ras. Ras expression consistently diminished anchorage-independent growth (AI), reduced E6 and E7 expression, and caused p53 induction in these cells. Conversely, AI was enhanced or maintained in Ras-transduced cervical cells that were immortalized with a 16E6/E7 retrovirus, and minimal effects on E6 and E7 expression were observed. Ras expression with either episomal HPV-16 or LXSN-E6/E7 was insufficient for tumorigenic growth suggesting that other events are needed for tumorigenic transformation. In conclusion, our results indicate that Ras-mediated transformation depends on the context of HPV oncogene expression and that this is an important point to address when developing HPV tumor models

Mejoramiento y tecnificación de máquina extrusora para la elaboración de ladrillos artesanales

In our country, Ecuador, there is community of makers of bricks. The present report intents to improve the process of elaboration of bricks through the improvement of an extruder machine, shaping of the cross section of a material by forcing it through a rigid die, to perfect the physics and mechanicals properties of bricks. This job analyze the design parameters of extruder machine using the fundaments of Mechanical Design, taking into account the requirements of bricks such as size and mechanicals and physics properties