Abstract A143: 4-methylumbelliferone and interleukin-12 combined therapy inhibit tumor growth by inducing antitumor immunity and reducing the presence of cancer stem cells in an murine hepatocellular carcinoma model associated with fibrosis
Authors: Malvicini Mariana , Rodriguez Marcelo M. , Fiore Esteban J. , Bayo Juan , Garcia Mariana , Bustillo Sofia Gomez , Atorrasagasti Catalina , Peixoto Estanislao , Mazzolini Guillermo 
Published: November 2016

The presence of immune cells as part of tumor microenvironment which includes many extracellular matrix (ECM) components and cancer cells may result in tumor growth inhibition. Then, the use of immunotherapy tools destined to generate or stimulates antitumor immunity has become an interesting therapeutic strategy for many tumor types. In this context, the excessive accumulation of ECM components including hyaluronan (HA), which typically occurs in liver cirrhosis, acts in synergy with different cells to promote hepatocarcinogenesis. Our aim was to evaluate the therapeutic effect of 4-methylumbelliferone (4Mu), a selective inhibitor of HA synthesis in combination with gene therapy of interleukin 12 mediated by an adenovirus (AdIL12) in a murine model of hepatocellular carcinoma (HCC) associated with advanced fibrosis induced by thioacetamide (TAA). Male C3H mice received an intrahepatic injection of 1,25×10e5 Hepa 129 cells (day 0) after 4 weeks of TAA administration (200 mg/kg). On day 5 mice were distributed in experimental groups (n = 8/group): saline; 4Mu 200 mg/Kg, drinking water (day 5); AdIL12 1×10e9 DICT50/ml, i.v (day 9) and 4Mu + AdIL-12. Antitumor efficacy and survival analyses were assesed. As a result, combined treatment induced a significant decrease of HCC tumor volume (p&lt;0.05) with an increased animal survival (p&lt;0.05). Flow cytometry analysis showed that the number of CD4+ and CD8+ cells in spleen and liver of combined therapy treated mice were significantly in comparison with untreated mice (p&lt;0.01). In addition, AdIL12 and AdIL12+4Mu therapies were able to generate a potent cytotoxic T cell response. Combined therapy was also able to decrease hepatic mRNA levels of the cancer stem cells (CSCs) markers CD133, CD90, EpCAM and CD44 (p&lt;0.01). The in vitro studies revealed that 4Mu was able to decrease the percentage of CD133+ expression in Hepa 129 cells, and when these cells are exposed to the supernatants derived from AdIL12-treated mice splenocytes more apoptotic events were observed. In conclusion, our results showed that the combined strategy has the ability to inhibit tumor growth by inducing a potent antitumor immune response and by reducing the presence of CSCs in mice with HCC associated with liver fibrosis.

Citation Format: Mariana Malvicini, Marcelo M. Rodriguez, Esteban J. Fiore, Juan Bayo, Mariana Garcia, Sofia Gomez Bustillo, Catalina Atorrasagasti, Estanislao Peixoto, Guillermo Mazzolini. 4-methylumbelliferone and interleukin-12 combined therapy inhibit tumor growth by inducing antitumor immunity and reducing the presence of cancer stem cells in an murine hepatocellular carcinoma model associated with fibrosis [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A143.