Suppression of hepatoma tumor growth by systemic administration of the phytotoxin gelonin driven by the survivin promoter

Abstract

Hepatocellular carcinoma (HCC) is one of the most common types of cancer worldwide. However, there is currently no effective therapy strategy in the clinical practice. Recombinant phytotoxin gelonin fused to other factors have been used to treat different cancers. But there have been no reports of gelonin gene therapy. In this study, we have constructed a recombinant plasmid which contained a tumor-specific survivin promoter to drive phytotoxin gelonin (pSur-Gel). And the cytotoxicity effects of pSur-Gel in HCC were also validated both in vitro and in vivo. The expression level of survivin was detetected in different liver cancer cell lines and nomal liver cell lines by western blot analysis, and a survivin promoter-driven green fluorescent protein (GFP) expression vectors (pSur-GFP) was also tested in liver cancer cell line HepG2 and normal liver cell line LO2. Moreover, phytotoxin gelonin expression experiment and cytotoxicity experiment of pSur-Gel was performed in HepG2 cells and LO2 cells in vitro. Furthermore, anti-tumor effect of pSur-Gel against HepG2 xenografts and toxicity of this gene were evaluated in the mice model. Finally, LDH release assay, apoptosis assay and immunoblot analyse LC3 conversion (LC3-I to LC3-II) were tested. We found that the expression of survivin protein was higher in liver cancer cell lines compared with the normal liver cells. Further study showed that the pSur-GFP and pSur-Gel was expressed specially in liver cancer cell other than in normal liver cells. pSur-Gel plasmid could effectively inhibit the proliferation of liver cancer cells (*P<0.05), and significantly repress the growth of HepG2 xenografts via intravenous in vivo (*P<0.05). Otherwise, compared to cytomegalovirus promoter-driven gelonin expression vectors (pCMV-Gel), no significantly systemic toxicity or organ injuries had been observed in pSur-Gel treated mice. Further studies revealed that the phytotoxin gelonin induced cell death might be mediated by apoptosis and the damage of cell membrane. Taken together, treating hepatocellular carcinoma with the pSur-Gel may be a novel and interesting cancer gene therapy protocol and is worthy of further development for future clinical trials.

DNA Polymerases as targets for gene therapy of hepatocellular carcinoma

“…As a new form for cancer treatment, gene therapy has been used for certain cancers, and a number of clinical trials including phase I, II and III trials for various cancers are underway [ 6 , 7 ]. Recent gene therapy for HCC is still confined to pre-clinical laboratory investigations, focusing on single or multiple genes dysregulated/mutated in HCC cells [ 8 - 12 ]. Gene therapy exhibits synergistic antitumor ability when combined with radiotherapy or chemotherapy [ 13 - 16 ], However, mutations or aberrant expressions of those target genes are highly variable in HCC, the strategy targeting one or a few of alterations may only be effective for a small group of patients.…”

Rocaglamide overcomes tumor necrosis factor-related apoptosis-inducing ligand resistance in hepatocellular carcinoma cells by attenuating the inhibition of caspase-8 through cellular FLICE-like-inhibitory protein downregulation

“…Thus, new strategies are required to address the resistance of HCC to apoptosis in order to improve the poor prognosis. Considerable attention has been directed towards investigating the effect of triggering apoptosis in HCC cells using natural products that stimulate DR-mediated apoptosis ( 31 ). In the present study, rocaglamide, a naturally occurring product, was demonstrated to sensitize TRAIL-resistant HCC cells to apoptosis through the suppression of c-FLIP in both in vitro and in vivo conditions.…”

Promoter-Operating Targeted Expression of Gene Therapy in Cancer: Current Stage and Prospect

“… Bmi-1 36 gastric cancer, prostate cancer, glioma cancer, etc. Survivin 39 , 40 , 60 , 61 , 63 liver cancer, gastrointestinal cancer, gallbladder cancer, etc. HER-2 40 , 41 prostate cancer, breast cancer, pancreatic cancer, etc.…”