A novel HBV antisense RNA gene delivery system targeting hepatocellular carcinoma

Retrovirus-mediated expression of dual-target antisense RNA in liver cells of transgenic mice and its influence on replication of hepatitis B virus

AIM: To detect the expression of X and P region dual-target antisense RNA of hepatitis B virus (HBV) mediated by ratroviral vector in the liver cells of transgenic mice and its effect on the replication of HBV DNA.

METHODS: The recombinant retroviral vector plasmids expressing dual-target antisense RNA complementary to HBV X and P region were constructed and then injected into the transgenic mice. The experimental mice were divided into blank, pLXSN, pLXSN-asX, pLXSN-asP, pLXSN-asXP, and pLXSN-seXP group. The total RNA, extracted from the mice at the 8^th wk, was reversely transcribed, and then the cDNA was amplified with polymerase chain reaction (PCR). Thereafter, agarose gel electrophoresis, sequencing analysis and fluorescent PCR were performed. The replication of HBV DNA was tested by fluorescence quantitative PCR.

RESULTS: The HBV dual-target antisense RNA was expressed in the liver cells of mice and with high efficiency. After 8 wk, the replications of HBV DNA (×10⁵ copies/g) were 7.24 ± 1.62, 9.49 ± 3.34, 2.60 ± 1.13, 2.83 ± 1.67, 3.24 ± 0.45, 6.52 ± 1.53 in blank, pLXSN, pLXSN-asX, pLXSN-asP, pLXSN-asXP and pLXSN-seXP group. The levels of HBV DNA were significantly higher in single- or dual-target antisense RNA groups than those in other groups (P < 0.05). However, there were no marked differences between control groups as well as between single-target and dual-target group (P > 0.05).

CONCLUSION: The hepatitis B virus dual-target antisense RNA can be expressed in the liver cells of transgenic mice with high efficiency, and it can inhibit the replication of HBV DNA in mice liver. However, there is no significant difference between single-target and dual-target RNA.

Enhanced efficiency and specificity of ovarian cancer gene therapy in rats with a novel nonviral gene delivery system (GE7) via intraovarian artery perfusion approach

Transfer of the herpes simplex virus type I-thymidine kinase gene, followed by the administration of ganciclovir (HSV1-tk/GCV) into ovarian cancer-derived cell line either in vitro or transplanted into nude mice has been shown to provide a potential strategy for the gene therapy of ovarian cancer. We investigated the antitumor effects of HSV1-tk/GCV strategy with a chemically induced rat ovarian cancer model and a tumor-selective gene delivery by a novel nonviral gene delivery system (GE7) through the ovarian artery and tail vein. We demonstrated the expression of a reporter gene, beta-gal gene, as well as HSV1-tk gene in tumors and other organs, evaluated the overall antitumor effects after the GCV treatment and analyzed the tumor cell cycle phase distribution. Via the ovarian artery route, the expressions of beta-gal and HSV1-tk in tumors were significantly stronger than those expressed in such organs as the hearts, livers, spleens, lungs and kidneys. However, no beta-gal and HSV1-tk were detected in the tumor tissues when administrated via the tail vein, and little was found in other organs. The cell cycle analysis showed that the total S-phase of tumor cells in the test intra-arterial treatment group was considerably higher than that of the controls. The weight of the tumor tissues in the group treated by the intra-arterial route (4.06+/-2.12 g) was much less than the group treated intravenously (18.25+/-8.34 g) (P<.01). These findings indicated that the administration of GE7/HSV1-tk complex via the ovarian artery route could be a promising avenue of future human ovarian cancer treatment.

Therapeutic polypeptides based on HBcAg18-27 CTL epitope can induce antigen-specific CD8+ CTL-mediated cytotoxicity in HLA-A2 transgenic mice

AIM: To explore how to trigger an HLAI-restricted CD8⁺ T cell response to exogenously synthesized polypeptides in vivo.

METHODS: Three mimetic therapeutic polypeptides based on the immunodominant CTL epitope of HBcAg, the B- epitope of HBV PreS₂ region and a common T helper sequence of tetanus toxoid were designed and synthesized with Merrifield’s solid-phase peptide synthesis method. Their immunological properties of inducing T_H1 polarization, CD8⁺ HBV-specific CTL expansion and CD8⁺ T cell mediated cytotoxicity were investigated in HLA-A2 transgenic mice.

RESULTS: Results demonstrated that the mimetic polypeptides comprised of the immunodominant CTL, B-, and T helper epitopes could trigger specifically and effectively vigorous CD8⁺ HBV-specific CTL-mediated cytotoxicity and T_H1 polarization of T cells in HLA-A2 transgenic mice.

CONCLUSION: A designed universal T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of CTL epitopes in vivo. And that the mimetic therapeutic peptides based on the reasonable match of the above CTL, B- and T helper epitopes could be a promising therapeutic peptide vaccine candidate against HBV infection.

Effect of HBeAg on the hepatitis B virus vertical transmission in neonates

AIM: To investigate the effect of HBeAg on the hepatitis B virus vertical transmission in neonates.

METHODS: HBsAg positive pregnant women were enrolled,and ELISA or Abbott was employed to detect the HBeAg and HBsAg in the peripheral blood of neonates and their mothers.

RESULTS: Fifty-seven HBsAg positive pregnant women were reconfirmed as HBsAg positive. Fifteen of them were detected as HBeAg positive. Eleven of 16 neonates born to 15 HBeAg positive mother were detected as HBeAg positive. Three neonates diagnosed as HBsAg positive by ELISA or Abbott reagents were detected as HBeAg positive. Statistic analysis indicated that HBeAg in newborns was an important risk factor.

CONCLUSION: HBeAg in neonates played an important role during HBV vertical transmission.