effect of wild type P53 gene transfer on growth properties and tumorigenicity of PANC-1 tumor cell line

The p53 protein function is essential for the maintenance of the nontumorigenic cell phenotype. Pancreatic tumor cells show a very high frequency of p53 mutation. To determine if restoration of wild type p53 function can be used to eliminate the tumorigenic phenotype in these cells, pancreatic tumor cell lines, PANC-1 and HTB80, differing in p53 status were stably transfected with exogenous wild type p53 gene. The transfection was performed using Polybrene/DMSO-Assisted Gene Transfer method. The wild type p53 gene integration into genomic DNA was detected by Southern blot and PCR. Furthermore, the expression of wild type p53 protein was detected in selected clones by immunohistochemistry and Western blot. While HTB80 cell line failed to produce a stable p53 expressing clone, the PANC-1 cells produced stable lines. Following characterization of clones, the growth rate and tumorigenicity of PANC-1 wild type p53 clones were compared to the control cells. Our data showed that the expression of wild type p53 decreased the growth rate of PANC-1 cells. It was also observed that the expression of wild type p53 in PANC-1 cells suppressed its potential for tumor formation in nude mice, completely, while the parental line leads to the formation of a relatively large tumor. Our results suggest that gene therapy based on restoration of wild type p53 protein function in pancreatic tumor cells with high amount of mutant p53 is a feasible option in pancreatic cancer treatment

Wild type p53 gene transfer increases chemosensitivity and apoptotic response of PANC-1 pancreatic tumor cell line

The effect of p53 gene therapy on chemosensitivity and apoptotic response of PANC-1 tumor cells, which express high amount of mutant p53, to cancer chemotherapeutic agents of Etoposide and Doxorubicin was investigated. Comparison of the chemosensitivity of PANC-1 cells to its wild type p53 transfectants showed that wt-p53 expressing transfectants are more sensitive to both Etoposide and Doxorubucin. It further showed that neither the PANC1 cells nor its wild type p53 transfectants arrested at G1 in response toX-irradiation. Furthermore, treatment of both PANC-1 cells as well as its wt-p53 transfectants with etoposide resulted in apoptosis despite the difference in their p53 status, although, the number of apoptotic cells of the wt-p53 transfectants was higher compared to the control cells. This evidence reinforce the view that combining p53 gene therapy with conventional chemotherapeutic agents may yield a more beneficial response than conventional treatments alone in pancreatic tumor cells with high amount of mutant p53