Low-molecular weight chitosan/vascular endothelial growth factor short hairpin RNA for the treatment of hepatocellular carcinoma.

AIMS: Vascular endothelial growth factor (VEGF) has been shown to be a key driving force for angiogenesis and tumor growth in hepatocellular carcinoma (HCC). As an emerging approach to block this angiogenic stimulator, the RNA interference (RNAi) technique has rapidly developed but is hindered for in vivo applications due to low cellular uptake and poor stability of small RNA. Based on low molecular weight chitosan (LMWC), a gene delivery system of short hairpin RNA (shRNA) directed against VEGF was constructed. The objective of this study was to investigate whether LMWC/shRNA nano-complexes can effectively inhibit VEGF expression in cancer cells and tumor tissues and suppress tumor growth in different HCC models. MAIN METHODS: The transfection experiment and Real-time qPCR assay were used to evaluate the transfection efficiency and gene suppression activity of LMWC/shRNA complexes in Hepa 1-6 murine hepatocarcinoma cells. The therapeutic effect of LMWC/ VEGF shRNA was further tested in ectopic and orthotopic liver cancer models. KEY FINDINGS: LMWC/VEGF shRNA complexes significantly inhibited VEGF expression of HCC cells and liver tumor tissues. LMWC obviously enhanced and prolonged the deposition of shRNA at the tumor site when LMWC/shRNA complexes were intravenously injected into orthotopic allograft liver tumor-bearing mice. The administration of LMWC/VEGF shRNA complexes by intratumoral or intravenous injection demonstrated more effective suppression of tumor angiogenesis and tumor growth in different HCC models compared with naked shRNA. SIGNIFICANCE: This study demonstrated the feasibility of using LMWC as a potential carrier for RNA interference drugs in liver cancer therapy.

Galactosylated α,ß-poly[(2-hydroxyethyl)-L-aspartamide]-bound doxorubicin: improved antitumor activity against hepatocellular carcinoma with reduced hepatotoxicity.

Galactosyl-terminated drug carriers are known to enhance drug accumulation in the liver, while possible accompanying hepatic toxicity is usually not clarified. This study developed a galactosyl-α,ß-poly[(2-hydroxyethyl)-L-aspartamide]-doxorubicin conjugate (Gal-PHEA-DOX) and investigated its therapeutic efficacy and safety in orthotopic hepatocellular carcinoma-bearing mice. Gal-PHEA-DOX had a galactosylation degree of 7.5 mol% and a DOX content of 8.9 wt%. A biodistribution study showed that Gal-PHEA-DOX sustainedly circulated in the plasma and highly accumulated in hepatocarcinoma. Free drug liberated from Gal-PHEA-DOX was relatively low in the liver and heart as compared with that of the DOX administration. The Gal-PHEA-DOX conjugate showed superior cytotoxicity against the hepatocellular carcinoma cell line HepG2 as compared with the nongalactosylated PHEA-DOX conjugate. Gal-PHEA-DOX exhibited comparable antitumor activity with PHEA-DOX in the S180-bearing mice, but more effective than PHEA-DOX or DOX in the Heps-bearing mice with negligible detrimental effect in the liver remnant. A systemic toxicity study showed that this conjugate did not show either cytotoxicity or hepatotoxicity at a relatively high dose, which would be harmful for free DOX. These results suggest that the Gal-PHEA-DOX conjugate has great potential for use in hepatocellular carcinoma chemotherapy because of its enhanced antitumor effect with reduced systemic toxicity including hepatotoxicity.

Antitumor activity and toxicological properties of doxorubicin conjugated to [alpha],[beta]-poly[(2-hydroxyethyl)-L-aspartamide] administered intraperitoneally in mice.

A polymer-drug conjugate was developed by conjugating doxorubicin (DOX) to [alpha],[beta]-poly[(2-hydroxyethyl)-L-aspartamide] (PHEA) with a succinic spacer. The suitability of PHEA-DOX in intraperitoneal chemotherapy was investigated both in vitro and in vivo. The results showed that the release rate of DOX from PHEA-DOX in S180 ascites was faster than that in mouse serum or in buffer solutions. An in-vivo antitumor study revealed that PHEA-DOX was more effective than DOX against solid S180 tumor after intraperitoneal injection at the same dose of 10 or 15 mg (DOX eq.)/kg, respectively. At a high dose of 28 mg (DOX eq.)/kg, which was lethal for free DOX to mice, PHEA-DOX could inhibit 61.5% of solid S180 tumor growth and markedly prolonged the survival time of ascetic S180-bearing mice. The toxicological effects of PHEA-DOX injected intraperitoneally in normal mice were assessed by using LD50, body weight increment, electrocardiography, blood biochemical indices, and myocardium histology, giving evidence that PHEA-DOX displayed considerably reduced systemic and cardiotoxicity compared with free DOX. All results suggest that PHEA-DOX has great potential for intraperitoneal chemotherapy because of its high therapeutic effects and few adverse side effects.

3,3'-Diindolylmethane attenuates experimental arthritis and osteoclastogenesis.

3,3'-Diindolylmethane (DIM) is a natural compound formed during the autolysis of glucobrassicin present in Brassica food plants. This study aimed to investigate the therapeutic efficacies of DIM on experimental arthritis. The effects of DIM on experimental arthritis were examined on a rat model of adjuvant-induced arthritis (AIA), with daily AIA paw swelling observation and histological/radiographic analysis. To elucidate the possible mechanisms of its action, serum cytokine levels as well as the expression of receptor activator for nuclear factor kappa B ligand (RANKL) in infected tissues were subsequently analyzed. The impact of DIM on osteoclastogenesis was further investigated on a mouse model of endotoxin-induced bone resorption (EIBR) and in vitro cultures of fibroblast-like cells and osteoblasts, with RANKL expression being evaluated with great interest. The administration of DIM was demonstrated to attenuate AIA in animal models, as judged by clinical and histologic indices of inflammation and tissue damage. On the one hand, DIM could reduce the expression of several inflammatory cytokines, which was, however, not adequate to prevent the development of the arthritis. On the other hand, DIM was shown to effectively inhibit the expression of RANKL, leading to the blockade of osteoclastogenesis and consequently an alleviation of experimental arthritis. Further in vitro and in vivo studies confirmed the inhibition of RANKL by DIM. DIM has shown anti-arthritis activity in animal models via inhibiting the expression of RANKL, and thus may offer potential treatments for arthritis and associated disorders.