Effect of Diphtheria Toxin-Based Gene Therapy for Hepatocellular Carcinoma.

Kenya Kamimura,Masato Ohtsuka,Takuro Nagoya,Hiroteru Kamimura,Norio Miyamura,Takeshi Yokoo,Yuji Kobayashi,Hiroshi Nishina,Akira Sakamaki,Hiroyuki Abe,Shuji Terai,Hiromi Miura,Norihiro Sakai

doi:10.3390/cancers12020472

Abstract

Hepatocellular carcinoma (HCC) is a major global malignancy, responsible for >90% of primary liver cancers. Currently available therapeutic options have poor performances due to the highly heterogeneous nature of the tumor cells; recurrence is highly probable, and some patients develop resistances to the therapies. Accordingly, the development of a novel therapy is essential. We assessed gene therapy for HCC using a diphtheria toxin fragment A (DTA) gene-expressing plasmid, utilizing a non-viral hydrodynamics-based procedure. The antitumor effect of DTA expression in HCC cell lines (and alpha-fetoprotein (AFP) promoter selectivity) is assessed in vitro by examining HCC cell growth. Moreover, the effect and safety of the AFP promoter-selective DTA expression was examined in vivo using an HCC mice model established by the hydrodynamic gene delivery of the yes-associated protein (YAP)-expressing plasmid. The protein synthesis in DTA transfected cells is inhibited by the disappearance of tdTomato and GFP expression co-transfected upon the delivery of the DTA plasmid; the HCC cell growth is inhibited by the expression of DTA in HCC cells in an AFP promoter-selective manner. A significant inhibition of HCC occurrence and the suppression of the tumor marker of AFP and des-gamma-carboxy prothrombin can be seen in mice groups treated with hydrodynamic gene delivery of DTA, both 0 and 2 months after the YAP gene delivery. These results suggest that DTA gene therapy is effective for HCC.

Highlights

Liver cancer is responsible for a great number of cancer-related deaths worldwide [1].For hepatocellular carcinoma (HCC), which is responsible for >90% of primary liver cancers [2], various conventional therapeutic options are available, including surgical resection, ablation, chemoembolization, systemic chemotherapy, molecularly targeted agents, and liver transplantation [3,4,5,6]
We focus on the suicide gene delivery strategy, which was recently reported to be elicited in a tumor-specific manner using transcriptionally targeted retroviral replicating vectors [28], targeting the genomic rearrangement in the tumor by using the genome-editing approach to insert the suicide gene [29]
Our results demonstrate that the overexpression of AFP promoter-controlled diphtheria toxin fragment A (DTA) inhibited cell growth through the inhibition of protein synthesis in an AFP-dependent manner, significantly decreased the occurrence of yes-associated protein (YAP)-induced Hepatocellular carcinoma (HCC) in normal mice liver; it inhibited the tumor marker increase, suggesting the clinical applicability of the procedure for HCC gene therapy

Summary

Introduction

Liver cancer is responsible for a great number of cancer-related deaths worldwide [1].For hepatocellular carcinoma (HCC), which is responsible for >90% of primary liver cancers [2], various conventional therapeutic options are available, including surgical resection, ablation, chemoembolization, systemic chemotherapy, molecularly targeted agents, and liver transplantation [3,4,5,6]. Cancers 2020, 12, 472 in determining therapeutic options, said therapies are insufficient for advanced-stage liver cancer in terms of efficacy. The potential promise for immune checkpoint inhibitors [8]; current therapies require further modifications to be fully effective [9,10,11]. This is partly due to the heterogeneity of tumor cells in HCC [12,13,14,15], which can cause a high risk of recurrence and drug resistance. Novel therapies are required for the effective treatment of advanced-staged HCC with poor hepatic reserve functions

Methods

Results

Conclusion