In vitro and in vivo efficacy of minocycline-based therapy for Elizabethkingia anophelis and the impact of reduced minocycline susceptibility.

OBJECTIVES: Elizabethkingia anophelis is inherently resistant to multiple antibiotics, except minocycline. This study aimed to determine the in vitro and in vivo efficacy of minocycline monotherapy and combination therapy against susceptible strains and the impact of reduced minocycline susceptibility. METHODS: Three clinical isolates and one laboratory-induced mutant with reduced minocycline susceptibility were included. Time-kill and checkerboard assays were used to assess in vitro efficacy and synergy, respectively. Galleria mellonella infection and mouse pneumonia models were used to assess in vivo efficacy, and a mouse thigh infection model was used to determine the bacterial load. RESULTS: Minocycline monotherapy exerted a modest inhibitory effect on three clinical minocycline-susceptible E. anophelis isolates in vitro, but delayed G. mellonella death and improved infected mouse survival; it also significantly reduced the in vivo bacterial load. Minocycline had decreased efficacy on G. mellonella and mice infected by the mutant with reduced minocycline susceptibility. Genome comparison revealed several spontaneous mutations associated with reduced minocycline susceptibility. Among eight antibiotics tested in combination with minocycline, rifampin consistently showed in vitro synergy. The addition of rifampin (1 mg/L) reduced the mutant prevention concentration of minocycline from 2-4 mg/L to < 0.5 mg/L. However, compared with monotherapy, the combination of rifampin and minocycline did not further reduce the bacterial load or improve the survival of G. mellonella or mice. CONCLUSION: Minocycline monotherapy was in vivo effective against susceptible E. anophelis. Reduced minocycline susceptibility due to spontaneous mutation decreased its therapeutic efficacy. In combination with rifampin, it prevented the in vitro emergence of reduced susceptibility but did not provide additional in vivo survival benefit.

Casticin Promotes Immune Responses, Enhances Macrophage and NK Cell Activities, and Increases Survival Rates of Leukemia BALB/c Mice.

Casticin, derived from Fructus Viticis, has anticancer properties in many human cancer cells, however, there is no report to show that casticin promotes immune responses and affects the survival rate of leukemia mice in vivo. The aim of this study is to evaluate the effects of casticin on immune responses and the survival rate of WEHI-3 cells generated in leukemia mice in vivo. Animals were divided into six groups: normal control mice, leukemia control mice, mice treated with ATRA (all-trans retinoic acid), and casticin (0.1, 0.2, and 0.4 mg/kg) treated mice. All animals were treated for 14 days and then measured for body weights, total survival rate, cell markers, the weights of liver and spleen, phagocytosis of spleen cells, NK cell activities and cell proliferation. Results show that casticin did not affect animal appearances, however, it increased body weights and decreased the weights of liver at 0.2 mg/kg and 0.4 mg/kg treatment. Casticin also decreased spleen weight at 0.2 mg/kg and 0.4 mg/kg treatment, increased CD3 at 0.1, 0.2 and 0.4 mg/kg doses and increased CD19 at 0.2 mg/kg treatment but decreased CD11b and Mac-3 at 0.1, 0.2 and 0.4 mg/kg treatment. Casticin (0.1, 0.2 and 0.4 mg/kg) increased macrophage phagocytosis from PBMC (peripheral blood mononuclear cell) and peritoneal cavity. Furthermore, casticin increased NK cells' cytotoxic activity and promoted T cell proliferation at 0.1-0.4 mg/kg treatment with or without concanavalin A (Con A) stimulation, but only increased B cell proliferation at 0.1 mg/kg treatment. Based on these observations, casticin could be used as promoted immune responses in leukemia mice in vivo.

Folate deficiency-triggered redox pathways confer drug resistance in hepatocellular carcinoma.

Patients with hepatocellular carcinoma (HCC) are prone to folate deficiency (FD). Here we showed that, in cell line-specific manner, FD caused resistance to FD-induced oxidative stress and multi-drug resistance (MDR). This resistance was due to upregulation of glucose-regulated protein 78 (GRP78) and Survivin. Using siRNA and Epigallocatechin gallate (EGCG), we found that GRP78 and Survivin cooperatively conferred MDR by decreasing FD-induced ROS generation. Our data showed that FD increases GRP78 and Survivin, which serve as ROS inhibitors, causing MDR in HCC. We suggest that folate supplementation may enhance the efficacy of chemotherapy.

Chitosan oligosaccharides in combination with Agaricus blazei Murill extract reduces hepatoma formation in mice with severe combined immunodeficiency.

Chitosan and Agaricus blazei Murill (ABM) extracts possess antitumor activities. The aim of the present study was to investigate whether chitosan, ABM extract or the two in combination were effective against tumors in tumor­bearing mice. The mice were subcutaneously injected with SK-Hep 1 cells and were then were divided into the following six groups: Group 1, control group; group 2, chitosan 5 mg/kg/day; group 3, chitosan 20 mg/kg/day; group 4, ABM (246 mg/kg/day) and chitosan (5 mg/kg/day) combined; group 5, ABM (984 mg/kg/day) and chitosan (20 mg/kg/day) combined; and group 6, ABM (984 mg/kg/day). The mice were treated with the different concentrations of chitosan, ABM or combinations of the two for 6 weeks. The levels of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and vascular endothelial growth factor (VEGF), and tissue histopathological features were examined in the surviving animals. Based on the results of the investigation, the treatments performed in groups 2, 3 and 4 were identified as being capable of reducing the weights of the tumors, however, group 4, which was treated with chitosan (5 mg/kg/day) in combination with ABM (246 mg/kg/day) was able to reduce the levels of GOT and VEGF. As a result, treatment with chitosan in combination with ABM may offer potential in cancer therapy and requires further investigation.

Effects of diallyl trisulfide on induction of apoptotic death in murine leukemia WEHI-3 cells in vitro and alterations of the immune responses in normal and leukemic mice in vivo.

Diallyl trisulfide (DATS), a chemopreventive dietary constituent and extracted from garlic, has been shown to against cultured many types of human cancer cell liens but the fate of apoptosis in murine leukemia cells in vitro and immune responses in leukemic mice remain elusive. Herein, we clarified the actions of DATS on growth inhibition of murine leukemia WEHI-3 cells in vitro and used WEHI-3 cells to generate leukemic mice in vivo, following to investigate the effects of DATS in animal model. In in vitro study, DATS induced apoptosis of WEHI-3 cells through the G0/G1 phase arrest and induction of caspase-3 activation. In in vivo study DATS decreased the weight of spleen of leukemia mice but did not affect the spleen weight of normal mice. DATS promoted the immune responses such as promotions of the macrophage phagocytosis and NK cell activities in WEHI-3 leukemic and normal mice. However, DATS only promotes NK cell activities in normal mice. DATS increases the surface markers of CD11b and Mac-3 in leukemia mice but only promoted CD3 in normal mice. In conclusion, the present study indicates that DATS induces cell death through induction of apoptosis in mice leukemia WHEI-3 cells. DATS also promotes immune responses in leukemia and normal mice in vivo.

Effects of chitosan on xenograft models of melanoma in C57BL/6 mice and hepatoma formation in SCID mice.

According to the World Health Organization, Complementary and alternative medicine (CAM) is a comprehensive term referring to traditional medical treatments and various forms of indigenous medicines, also known as indigenous or folk medicine. Cancer patients often use CAM in the form of nutritional supplements, psychological techniques and natural medical approaches in the place of or in parallel to conventional medicine. The present study aimed to determine if Chitosan can inhibit lung metastasis and hepatoma formation, by studying xenograft of B16F10 melanoma cells in C57BL/6 mice and of Smmu 7721 cells in SCID mice, respectively. For the lung metastasis model, after a five-week treatment, the survival rates of B6 mice were 15% for the control group and 35%, 20%, 45% and 40% for the 320,000 kDa, 173,000 kDa, 86,000 kDa and 8,000 kDa molecular-weight treatment groups, respectively. Chitosan treatment dramatically increased lifespan and inhibited tumor metastasis especially in treatment groups of the low-molecular weight compound. For the hepatoma growth model, the size of the liver tumor mass was approximately >14 mm in the control group. In comparison to the control group, the tumor mass grew slowly with Chitosan treatment, especially at the low-molecular weight treatment group. Chitosan slowed-down the rate of tumor growth but did not inhibit tumor formation. Data presented herein demonstrate that Chitosan has anticancer effects and thus further study of the substance is warranted to examine for mechanisms of action and optimal dosage.