Preclinical study of oncolytic adenovirus-mediated cytotoxic gene therapy with gemcitabine for chemoresistance of desmoplastic tumor.

Abstract

e15507 Background: Pancreatic cancer is a highly lethal disease. Excessive accumulation of tumor extracellular matrix (ECM) and epithelial-to-mesenchymal transition (EMT) phenotype are two main contributors to drug resistance in desmoplastic pancreatic tumors. Methods: To overcome the limitations of various conventional therapeutics against desmoplastic pancreatic cancer, we utilized an oncolytic adenovirus (oAd) for combination therapy with gemcitabine, a standard chemotherapeutic for pancreatic cancer treatment. Here, we report the results of preclinical pharmacology and efficology studies conducted in pancreatic cancer model. Results: Efficacy studies in orthotopic pancreatic xenograft tumor model demonstrated that oAd effectively attenuated tumor cell proliferation. oAd further prevented metastasis of pancreatic cancer and sensitized pancreatic tumor to gemcitabine treatment. Furthermore, oAd augmented drug penetration and dispersion within pancreatic tumor xenografts and patient-derived pancreatic tumor spheroids. These results suggest that oAd enhance the therapeutic effect of chemotherapeutic agent in chemo-resistant and desmoplastic pancreatic tumor, thus overcoming the preexisting limitations of standard treatments. Conclusions: Overall, these results demonstrate that local administration of an oncolytic adenovirus with gemcitabine is well tolerated and support moving this investigational approach into human trials.