Pancreatic cancer remains one of the most difficult malignancies to treat. It ranks 4th as a cause of cancer related death in USA and accounted for an estimated 29,000 deaths in 1998. Complete surgical resection offers the only potential for long term survival. Nevertheless, the overall 5 year survival for all stages of surgically respectable disease is only 21 percent. The molecular clues to the origin of this disease are emerging. Activation of oncogenes and inactivation of tumor suppressor genes such as p53, k-ras, p16, p21/WAF and FHIT in pancreatic cancer have been shown to play an important role in tumorigenesis. In our study we will focus on the fragile histidine triade gene (FHIT) located at chromosome 3p14.2 and affected in approximately 66 percent of human pancreatic cancer. The nature of damages to the 3p15.2 locus has recently been further elucidated and underlie FHIT as a tumor suppressor gene. The 1.1-kb FHIT cDNA transcript encodes a protein (Fhit) with in vitro dinucleoside 5`,5""""""""-P1, P3- triphosphate (Ap3A) hydrolase activity. Tumor suppressor activity of Fhit is assumed to be associated with involvement of the Fhit. Ap3A complex in cytokine signaling pathways(s) controlling cell proliferation and Fhit seems to be involved in a p53 independent apoptotic pathways. In order to clarify the function of Fhit as a tumor suppressor in pancreatic cancer and to explore the potential therapeutic role of FHIT gene transfer in pancreatic cancer, experimental data are needed. We will study the effects of FHIT gene overexpression mediated by a recombinant adenoviral vector (rAd-FHIT) on cell proliferation, apoptosis and cell-cycle processes in pancreatic cancer cell lines and on tumorigenicity and tumor growth in nude mice. The in vitro model will give us information about the therapeutic efficacy of the Adenoviral gene transfer system by measuring the levels of Fhit cDNA expression by RT-PCR and Fhit protein expression by Western blot and immunochemistry. To evaluate the induction of apoptosis, we will evaluate the level of transfected cells in G0/G1 compared to control cells by FACS analysis. The effect of systemic therapy on in vitro tumor growth inhibition in transduced and nontransduced cells will be evaluated by the MTT test. The in vivo effect on tumor suppression will be evaluated by observing the subcutaneous tumor growth in nude mice injected intratumorally with Ad-FHIT compare to the empty vector. Adenoviruses have been studied extensively and used safely for human vaccine preparations and Rad vectors have shown to be effective gene delivery vehicles, therefore, the results of this study may well result in therapeutic implications for human pancreatic cancer.
| Dumon, K R; Ishii, H; Vecchione, A et al. (2001) Fragile histidine triad expression delays tumor development and induces apoptosis in human pancreatic cancer. Cancer Res 61:4827-36 |
