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Normal hepatocytes express connexin32 (Cx32), which forms gap junctions at cell‑cell contact areas. The aim of the present study was to investigate whether Cx32 mediates the cell death‑inducing effects of ultrasound microbubbles carrying the herpes simplex virus thymidine kinase (HSV‑TK) suicide gene against hepatocellular carcinoma cells in vitro and in vivo. HepG2 cells were exposed to different concentrations of trans‑retinoic acid (ATRA) in culture, to evaluate the intrinsic antitumor effect of ATRA. Detailed in‑vitro and in‑vivo investigations on the antitumor effects of ATRA via Cx32 mediation were performed, and the possible underlying mechanisms of action of the compound were then examined. The gene expression of HSV‑TK transfected by ultrasound wave irradiation in the HepG2 cells was quantified using reverse transcription‑quantitative polymerase chain reaction analysis. The effects on cell death were assessed using an MTT assay. The protein expression levels of Cx32 in ATRA‑untreated or ATRA‑treated tissues were quantified by immunohistochemical analysis and Western blot assays. The HSV‑TK gene was successfully transfected into the HepG2 cell using ultrasound wave irradiation, and was stably expressed. Compared with the other groups, the HSV‑TK gene group treated with ATRA exhibited an increased number of apoptotic cells (P

To explore the anti-tumor effect of high-intensity focused ultrasound (HIFU) combined with herpes simplex virus thymidine kinase (HSV-TK) gene-loaded ultrasound-targeted microbubbles on VX2 rabbit liver tumors.Seventy-five New Zealand white rabbits were randomly divided into five groups after the models of VX2 rabbit liver tumors were established: (a) HIFU group; (b) HIFU and HSV-TK group (HIFU + HSV-TK); (c) HIFU, HSV-TK and ultrasound group (HIFU + HSV-TK + US); (d) HIFU, HSV-TK gene-loaded microbubbles and ultrasound group (HIFU + HSV-TK-MBs + US); and (e) HSV-TK gene-loaded microbubbles and ultrasound group (HSV-TK-MBs + US). After 2 weeks of VX2 liver tumor implantation, rabbits in groups (a), (b), (c) and (d) received HIFU to establish rabbit models of residual tumor by ablating 80% of the tumor volume. After HIFU ablation, rabbits in different groups received MBs wrapped around HSV-TK or HSV-TK solution via marginal ear veins and/or local ultrasonic irradiation to the tumor. Six rabbits in each group were sacrificed 48 h after the corresponding treatment, and tumors were extracted for in vitro experiments. Thymidine kinase mRNA was detected by the real-time polymerase chain reaction. The green fluorescent protein expression in liver tumor was detected by western blotting and immunohistochemistry. Tumor cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. The growth curves of VX2 liver tumors and survival curves of rabbits were compared.Forty-eight hours after treatment, TK mRNA and protein were the highest in the HIFU + HSV-TK + US + MBs group and the HSV-TK + US + MBs group (p 0.05). At 48 h after treatment, the apoptotic index of tumor cells in HIFU + HSV-TK-MBs + US group was the highest (p 0.05). Compared to other groups, HIFU combined with MBs wrapped HSV-TK suicide gene significantly inhibited tumor growth in vivo (p 0.05) and prolonged the survival time of animals (p 0.05).HIFU combined with HSV-TK gene-loaded ultrasound-targeted MBs significantly inhibited the growth of VX2 rabbit liver tumors in vivo and prolonged the survival time of the animals, providing a novel gene delivery method and a novel strategy for liver tumor treatment.

To observe the effect of ultrasound microbubble carrying herpes simplex virus thymidine kinase hepatocellular carcinoma in mice.Kunming mice were inoculated subcutaneously with H22 tumor cells. 40 male mice bearing subcutaneous hepatoma were randomized into 4 groups: PBS (group A), HSV1-TK (group B), HSV1-TK (group C), and microbubble carrying HSV1-TK (group D) were injected into the tail vein every 3 days. Mice in group C and D were exposed to ultrasound. The expression of TK protein was detected by western blot. Ganciclovir (GCV) was intraperitoneally injected at a dose of 100 mg x kg (-1) x d(-1) in group B, group C and group D. The tumor size was measured every 2 days.TK gene could be injected precisely into hepatocellular carcinoma with ultrasound monitor, and the expression of TK protein was found in all 4 groups. Expression in group D was higher than others (P0.05). The rate of tumor growth inhibition were 0 in group A, 3.90%+/-1.80% in group B, 22.70%+/-2.86% in group C, 41.25%+/-3.20% in group D (group B vs group C, P0.05; group D vs group C, P0.05; group D vs group B, P0.05).Ultrasound microbubble not only improve target gene therapy, but also enhance transfection efficiency.