Farnesyltransferase inhibitor (L-744,832) restores TGF-beta type II receptor expression and enhances radiation sensitivity in K-ras mutant pancreatic cancer cell line MIA PaCa-2.

Activated ras is known to dysregulate TGF-beta signaling by altering the expression of TGF-beta type II receptor (RII). It is well documented that tumor cells harboring mutant ras are more resistant to radiation than cells with wild-type ras. In this study, we hypothesized that the use of farnesyltransferase inhibitor (FTI, L-744,832) may directly restore TGF-beta signaling through RII expression via ras dependent or independent pathway leading to induction of radiation sensitivity.

Influence of p53 status on radiation and 5-flourouracil synergy in pancreatic cancer cells.

Background: While p53 protein plays an important role in the regulation of radiosensitivity and chemosensitivity in many tumors, the role of p53 in the combined management of tumors that harbor mutations in the p53 gene have not been fully defined. This study was undertaken to evaluate the impact of wild-type or mutant p53 status on the synergistic effects of 5-Fluorouracil (5-FU) and radiation (XRT) in pancreatic tumors.

Materials And Methods: Three pancreatic tumor cell lines, one containing wild-type functional p53 (Capan-2) and two containing mutant p53 (Panc-1 and MIA PaCa-2), were used in this study.

Restoration of transforming growth factor-beta signaling enhances radiosensitivity by altering the Bcl-2/Bax ratio in the p53 mutant pancreatic cancer cell line MIA PaCa-2.

In this study, we investigated whether lack of transforming growth factor beta (TGF-beta) type II receptor (RII) expression and loss of TGF-beta signaling played a role in radiation resistance of pancreatic cancer cells MIA PaCa-2 that possess a mutated p53 gene. Transfection of this cell line with a RII cDNA led to a stimulation of the transcriptional activity of p3TP-Lux, a TGF-beta-responsive reporter construct. The RII transfectants (MIA PaCa-2/RII) showed a significant increase in sensitivity to radiation when compared with MIA PaCa-2/vector cells.