Vesicular stomatitis virus matrix protein gene enhances the antitumor effects of radiation via induction of apoptosis.

Vesicular stomatitis virus (VSV) matrix (M) protein can directly induce apoptosis by inhibiting host gene expression when it is expressed in the absence of other viral components. Previously, we found that the M protein gene complexed to DOTAP-cholesterol liposome (Lip-MP) can suppress malignant tumor growth in vitro and in vivo; however, little is known regarding the biological effect of Lip-MP combined with radiation. The present study was designed to determine whether Lip-MP could enhance the antitumor activity of radiation. LLC cells treated with a combination of Lip-MP and radiation displayed apparently increased apoptosis compared with those treated with Lip-MP or radiation alone. Mice bearing LLC or Meth A tumors were treated with intratumoral or intravenous injections of Lip-MP and radiation. The combined treatment significantly reduced mean tumor volumes compared with either treatment alone in both tumor models and prolonged the survival time in Meth A tumor models and the intravenous injection group of LLC tumor models. Moreover, the antitumor effects of Lip-MP combined with radiation were greater than their additive effects when compared with the expected effects of the combined treatment in vivo. This study suggests that Lip-MP enhanced the antitumor activity of radiation by increasing the induction of apoptosis.

Liposomal quercetin efficiently suppresses growth of solid tumors in murine models.

PURPOSE: Quercetin is a potent chemotherapeutic drug. Clinical trials exploring different schedules of administration of quercetin have been hampered by its extreme water insolubility. To overcome this limitation, this study is aimed to develop liposomal quercetin and investigate its distribution in vivo and antitumor efficacy in vivo and in vitro. EXPERIMENTAL DESIGN: Quercetin was encapsulated in polyethylene glycol 4000 liposomes. Biodistribution of liposomal quercetin i.v. at 50 mg/kg in tumor-bearing mice was detected by high-performance liquid chromatography. Induction of apoptosis by liposomal quercetin in vitro was tested. The antitumor activity of liposomal quercetin was evaluated in the immunocompetent C57BL/6N mice bearing LL/2 Lewis lung cancer and in BALB/c mice bearing CT26 colon adenocarcinoma and H22 hepatoma. Tumor volume and survival time were observed. The mechanisms underlying the antitumor effect of quercetin in vivo was investigated by detecting the microvessel density, apoptosis, and heat shock protein 70 expression in tumor tissues. RESULTS: Liposomal quercetin could be dissolved in i.v. injection and effectively accumulate in tumor tissues. The half-time of liposomal quercetin was 2 hours in plasma. The liposomal quercetin induced apoptosis in vitro and significantly inhibited tumor growth in vivo in a dose-dependent manner. The optimal dose of liposomal quercetin resulted in a 40-day survival rate of 40%. Quantitative real-time PCR showed that liposomal quercetin down-regulated the expression of heat shock protein 70 in tumor tissues. Immunohistochemistry analysis showed that liposomal quercetin inhibited tumor angiogenesis as assessed by CD31 and induced tumor cell apoptosis. CONCLUSIONS: Our data indicated that pegylated liposomal quercetin can significantly improve the solubility and bioavailability of quercetin and can be a potential application in the treatment of tumor.

[Nanoliposomal quercetin inhibits formation of malignant ascites of hepatocellular carcinoma].

BACKGROUND & OBJECTIVE: Quercetin is a potential chemotherapeutic drug with many biological activities. However, the insolubility of quercetin seriously limits its clinical use. This study was to investigate the biodistribution of quercetin encapsulated by pegylated nanoliposomes and its therapeutic efficacy on the formation of carcinomatous ascites of hepatocellular carcinoma in mice. METHODS: Nanoliposomal quercetin was prepared with conventional rotary evaporation method. BALB/c mice inoculated with hepatocellular carcinoma cells (H22) at the anterior right subaxilla for twelve days were given intravascular injection with nanoliposomal quercetin at 1.5 mg/body (based on quercetin) at different time points. Then the levels of quercetin in the plasma, tumor tissues and normal organs were tested by high pressure liquid chromatography (HPLC). Various dosages of nanoliposomal quercetin were peritoneally given to tumor-bearing mice to determine the optimal dose. The tumor-bearing mice were treated intraperitoneally with 100 mg/kg nanoliposomal quercetin once a day for 14 days. The formation of malignant ascites, increase of body weight, survival time and peritoneal capillary permeability were assessed. Apoptotic cells in ascites were detected by flow cytometry. RESULTS: Nanoliposomal quercetin was a spherical particle with 25% drug content (W/W) and 130+/-20 nm in diameter. Nanoliposomal quercetin effectively aggregated in tumor tissues and its half-life period was 4 h. Nanoliposome quercetin inhibited the formation of malignant ascites of hepatocellular carcinoma model in a dose-dependent manner. Moreover, 100 mg/kg nanoliposomal quercetin significantly enhanced the apoptosis of cancer cells in ascites, inhibited the increase of body weight, reduced peritoneal capillary permeability and prolonged the survival time of tumor-bearing mice compared with PBS control. CONCLUSION: Nanoliposomal quercetin can effectively accumulate in tumor tissues and inhibit the formation of malignant ascites, thus it might be used as a potential antitumor drug which deserves future study.