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 detected in different
liver cancer cell lines and normal 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.
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