Patients diagnosed with advanced pancreatic ductal adenocarcinoma (PDAC) face the grim reality that current therapies, including gemcitabine (Gem) and several targeted combinatorial approaches are marginally effective. The long-term goal of this project is to establish the newly identified small drug-like molecule, AS-10, as an effective and safe PDAC therapy, both as a single agent and/or in combination with Gem, the current standard of care. AS-10, discovered through extensive structure-activity relationship (SAR) studies in Dr. Sharma?s laboratory, is selectively lethal to PDAC cells, while being non-toxic to normal cells. It is >200 times more cytotoxic than Gem to PDAC cells, including the Gem-resistant male derived Panc-1, Gem-moderate male derived MIA PaCa-2, and Gem-sensitive female derived BxPC-3 cells. AS-10 induces G1 and G2 cell cycle arrests and caspase-mediated apoptosis. In addition, AS-10 acts by inhibiting pro-survival and a pro- inflammatory NF-?B pathway in PDAC cell lines, which either show constitutive NF-?B activation, or TNF-? stimulated NF-?B activation. Notably, Gem is known to develop resistance due to up-regulation of NF-?B. This strongly suggests that a combination of NF-?B -inhibitor AS-10 and -activator Gem should work synergistically to target PDAC tumor cells, thus boosting current chemotherapy. Indeed, the preliminary studies support this assumption showing AS-10 to potentiate effect of Gem in reducing cell viability of and inducing apoptosis in PDAC cells. Furthermore, AS-10 inhibits growth of PDAC and colon cancer xenografts without any apparent systemic toxicity, demonstrating its safety in vivo and efficacy as a single agent. Therefore, the hypothesis is that AS-10 will be an efficacious PDAC therapy as a single agent and/or in combination with Gem, against in situ PDAC tumor growth and metastasis.
The Specific Aims are: (1) To establish dose-responses of AS-10 and its combination with Gem to inhibit tumor growth and metastasis to inform the therapeutic index (window) in PDAC xenograft mouse models, and (2) To profile in vivo pharmacodynamic (PD) targets associated with the therapeutic effects of AS- 10. The experimental approach to be used includes optimizing the oral dose/dosing frequency of AS-10 and the combination treatment by evaluating pharmacokinetics (PK) and maximum tolerated dose (MTD) in mice and evaluating the efficacy of both regimens to inhibit PDAC xenograft growth and metastasis in orthotopic implantation athymic nude mouse model using human Panc-1-luc and BxPC-3-luc cell lines with in vivo imaging and endpoint necropsy validation. The profiling of underlying mechanisms of action will then be done by identifying potential in vivo PD molecular targets accounting for efficacy using PDAC xenograft models. Successful outcomes are expected to identify a novel orally bioavailable agent that could be used alone and/or in combination with Gem to treat PDAC and will provide a solid rationale to evaluate in depth mechanism, efficacy studies and eventually clinical trials in PDAC patients.
To date, there are no effective drugs available for the treatment of Pancreatic Cancer (PC). In this proposal, we will evaluate therapeutic efficacy and mechanisms of action(s) of our newly developed NF-?B modulator small molecule, AS-10, which is orally bioavailable, has a high therapeutic index, is effective alone, and acts synergistically in combination with current standard of care gemcitabine to induce apoptosis in PC tumor cells. If successful, this study would identify a novel agent that would be effective alone as well as in combination with gemcitabine, which in long term, may help increase the length and quality of life of patients with aggressive pancreatic ductal adenocarcinoma (PDAC) tumors.
