Abstract 4200: Novel treatment strategy for pancreatic cancer
Authors: Chheda Chintan , Murali Ramachandran , Grippo Paul , Uyeminami Dale , Pinkerton Kent , Pandol Stephen , Edderkaoui Mouad 
Published: August 2015

Background: Solid association exists between high expression level of glycogen synthase kinase 3 beta (GSK-3β) and pancreatic cancer (PaCa) progression in humans. GSK-3β inhibition in a mouse orthotopic model of PaCa induced tumor shrinkage. However, GSK-3β inhibition stimulates pro-metastasis epithelial to mesenchymal transition (EMT). HDAC1/2 is involved in regulation of EMT in PaCa cells. We developed a novel strategy based on the combination of GSK-3β inhibition with inhibition of HDAC1 to prevent cancer cell survival, EMT and metastasis in vitro and in vivo. We designed, synthesized and tested a novel dual-inhibitor CSME-357 which inhibits both the proteins.

Methods: Pdx-Cre;LSL-Kras (KC) mice were ip injected with GSK-3β inhibitor TDZD-8 and/or HDAC1/2 inhibitor Saha. Pancreatic intraepithelial neoplasia (PanIN) lesions, fibrosis, and inflammation were measured by IHC. Pancreatic cancer cell lines MIA PaCa-2, BxPC3, AsPC1 were cultured in the presence of HDAC and/or GSK-3β inhibitors or with the novel compound CSME-357 which inhibits both proteins. Cell survival and apoptosis were measured by MTT assay and DNA fragmentation, respectively. EMT and cancer stemness markers, histone acetylation and GSK-3β level were measured by IHC and Western in tissue and cells. Invasion of the cells was measured by invasion assay. Ability of the cells to form metastatic niches in nude mice was measured by injecting PaCa cells in mice tails in the presence or absence of CSME-357 and live mice were analyzed by MRI and by tissue analysis after necropsy.

Results: Treatment of KC mice with Saha decreased the level of PanIN lesions, fibrosis, inflammation, and EMT. TDZD-8 potentiated the effect of Saha on PanIN prevention. Saha and TDZD-8 decreased EMT in KC mice. Pharmacological and molecular inhibitions of GSK-3β significantly, dose dependently, and synergistically decreased proliferation and at a lesser extent stimulated apoptosis in PaCa cell lines. GSK-3β inhibition stimulated EMT in PaCa cells; whereas, Saha reversed this effect. CSME-357 significantly and more potently (compared to the combination of two inhibitors) decreased proliferation, invasion and EMT and stimulated apoptosis in PaCa cells. Significance was achieved at 300nM. Toxicity assays showed no to very little toxicity of the novel compound. CSME-357 decreased the ability of cancer cells to form metastatic niches in nude mice.

Conclusion: Combination of HDAC1 and GSK-3β inhibitions induced a triple beneficial effect by decreasing proliferation, stimulating apoptosis and inhibiting EMT/metastasis. CSME-357 is a novel compound with promising anti-cancer properties. CSME-357 is a very potent inhibitor for both GSK-3β and HDAC1/2; in addition, CSME-357 prevents cancer cell growth, resistance to apoptosis, EMT, invasion and metastasis.

Note: This abstract was not presented at the meeting.

Citation Format: Chintan Chheda, Ramachandran Murali, Paul Grippo, Dale Uyeminami, Kent Pinkerton, Stephen Pandol, Mouad Edderkaoui. Novel treatment strategy for pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4200. doi:10.1158/1538-7445.AM2015-4200