Project 1: Development of Novel Gene Therapy for Pancreatic Cancer
Mien-Chie Hung, Ph.D.
Milind Javle, M.D.
We have completed the first two proposed specific aims. With the support of MD Anderson's SPORE in Pancreatic Cancer, we successfully developed a robust pancreatic cancer-specific expression vector, CCKAR-VISA (C-VISA), and its application in pancreatic tumor-bearing mouse models. Systemic administration of C-VISA-driven BikDD, a potent pro-apoptotic gene, in DNA:liposome complexes vigorously repressed growth of pancreatic tumors and metastasis and prolonged survival in multiple orthotopic mouse models. These findings constitute a novel strategy for potentially eliminating pancreatic cancer safely and effectively and provide useful models for noninvasively spatiotemporal monitoring.
The tissue microarray study will also be continued to examine relationship of Akt, EZH2 and H3 K27 trimethylation in pancreatic tumors and to establish whether associated with clinical outcomes.
- To continue preclinical gene therapy experiments using orthotopic animal models of pancreatic cancer to establish a therapeutically effective approach
- To identify pancreatic cancer-specific expression/delivery vectors in order to selectively express the therapeutic gene in pancreatic cancer cells, thereby preferentially inhibiting pancreatic cancer cell growth
- To evaluate the therapeutic efficacy of combined gene therapy and conventional chemotherapy or radiation therapy
This project has developed a sophisticated pancreas-specific promoter based on the cholecystokinin type A (CCKAR) receptor that employs a two-step transcriptional activation system (VISA) driving the BikDD proapoptotic gene. This year we were able to demonstrate the feasibility and therapeutic efficacy of VISA-based gene therapy in preclinical settings, i.e., VISA-BikDD exhibits lower tumor growth, prolonged survival rate and increased apoptosis of tumor cells, and this system can be administered systemically and is more effectively than CMV-BikDD in PancO2 and AcPC-1 orthotopic models. Significantly, VISA-BikDD has lower toxicity than CMV-BikDD does.
These characteristics of VISA-BikDD warrant clinical trials in pancreatic cancer patients.
Project 3: NFkB Signaling Pathways in Pancreatic Cancer Biology and Therapy
Paul J. Chiao, Ph.D.
Fazlul H. Sarkar, Ph.D.
Razelle Kurzrock, M.D.
NFkB is an important constitutively activated nuclear transcription factor in pancreatic cancer. Targeting its activation is a key focus of this project. Curcumin appears to be an important naturally occurring inhibitor of NFkB. We are continuing to test this concept. Completion of our proposed studies will (1) provide a better understanding of the role of cellular signaling inhibitors and their ability to block NFkB-related pathways to sensitize pancreatic cancer cells to apoptosis, (2) reveal insights into the the mechanisms of action of these agents, (3) suggest appropriate combinations for clinical testing and (4) establish the efficacy of these agents in appropriately designed clinical trials. The information obtained from our studies is anticipated to directly impact the management of patients with pancreatic cancer and provide a direction for the future studies required to extend the survival of these patients.
- To determine whether the effects of inhibiting NF-kB activity will enhance gemcitabine-induced apoptosis in pancreatic cancer cell lines grown in culture and implanted in the pancreas of nude mice
- To examine whether ERRP-mediated inhibition of EGFR and genistein-mediated Akt signaling cascades will sensitize various pancreatic cancer cell lines to gemcitabine-induced apoptosis
- To study the clinical activity of the NFkB inhibitor curcumin and to examine the potential to improve the bioavailability of curcumin by developing a liposomal formulation.
A clinical trial using the dietary component/NFkB inhibitor curcumin has been completed anti-cancer activity has been seen. A manuscript has been submitted describing these results and an abstract is included in the progress report Appendix.
Based on on-going preclinical studies completed this year additional trials have been developed or are planned including studies of a liposomal formulation of curcumin (toxicology testing), and genistein (Novasoy) in combination with gemcitabine and erlotinib (IRB-approved protocol currently accruing patients).
Project 5: DNA Repair as a Risk Factor for Pancreatic Cancer
Marsha Frazier, Ph.D.
Donghui Li Ph.D.
Douglas Evans, M.D.
These studies are important, as they will allow us use functional SNPs to help identify which patients are more likely to benefit from the preoperative chemo-radiation followed by surgery. Ultimately, this approach can lead to a genomically tailored treatment for pancreatic cancer.
To determine if polymorphisms in DNA repair genes, and/or polymorphism in cell cycle genes modulate response and survival of the estimated 250 pancreatic cancer patients who have or will have received pre-operative treatment with gemcitabine and radiation. Responses will be assessed by computerized tomography obtained before and four to six weeks after pre-operative treatment. Survival after surgery will be assessed using Kaplan-Meier survival estimates. We hypothesize that the DNA repair gene and cell cycle gene polymorphisms will regulate the response to therapy and the survival time of patients treated with gemcitabine-based pre-operative chemoradiation therapy.
The DNA repair gene polymorphisms will be from the nucleotide excision repair (NER) pathway and will include ERCC1, XPC, XPD/ERCC2, XPA, XPG/ERCC5, XPB/ERCC3 and XPF/ERCC4. The cell cycle genes to be examined will be cyclin D1, p16, p21 and p53. These studies may help to determine which subset of patients is more likely to respond to combined modality preoperative treatment with gemcitabine and radiation.
Using the techniques of molecular epidemiology we have developed exciting preliminary data that inter-individual differences in DNA repair influences response to genotoxic therapy as well as the risk of pancreatic cancer. In addition, in collaboration with Dr. Donghui Li's work on the molecular epidemiology of pancreatic cancer, we have taken the first steps toward the development of a risk model for sporadic pancreatic cancer.