Mouse Anti Human Glutathione S-transferase Mu2 Hybridoma [DQUD-HTUNv3-2]

The roles of glutathione S-transferase pi 1 (GSTP1), glutathione S-transferase mu 2 (GSTM2) and glutathione S-transferase alpha 1 (GSTA1) in cisplatin (DDP)-resistance of solid cancer cells (A549/DDP, SKOV3/DDP and SGC7901/DDP) were compared following expression downregulation with small interfering RNAs (siRNAs). DDP cytotoxicity was reflected by its half maximal inhibition concentration (IC50) calculated from data using a Cell Counting Kit-8 assay; cell apoptosis was examined using flow cytometry and Hoechst 33342 staining. Higher activities of GST were detected in the cytosol of DDP-resistant cells, compared with those in the parental DDP-susceptible cells. The silencing efficacy of each positive siRNA was supported by western blot analysis. GSTP1 silencing resulted in a 4-fold sensitization of SGC7901/DDP cells to DDP cytotoxicity, but negligible sensitization of SKOV3/DDP and A549/DDP cells. GSTM2 silencing sensitized SKOV3/DDP and A549/DDP cells to DDP cytotoxicity by 2-fold, but did not sensitize SGC7901/DDP cells. Notably, GSTA1 silencing enhanced DDP cytotoxicity in SGC7901/DDP cells by 6-fold, in A549/DDP cells by 5-fold and in SKOV3/DDP cells by 2-fold. The combined actions of positive siRNAs and DDP increased the percentages of apoptotic cells in the DDP-resistant solid cancer cells compared with the combined actions of DDP and the negative siRNAs. The present findings indicated that GSTA1 is a predominant GST isozyme associated with DDP resistance of SGC7901/DDP, A549/DDP and SKOV3/DDP cells; GSTA1-specific inhibitors may be general sensitizers of SGC7901/DDP, A549/DDP and SKOV3/DDP cells to DDP cytotoxicity through the promotion of cell apoptosis.

Aims: Morphine strongly induces reactive oxygen species (ROS). The deleterious actions of morphine can be countered by antioxidant system. In the present study, we investigated the expression levels of nine antioxidant genes in human SH-SY5Y cells treated with morphine. Main methods: The cells were treated with three final concentrations of morphine (1, 5, and 10 mu mol) for four exposure times (1 h, 24 h, 72 h and 18 days). The mRNA levels were determined using quantitative real-time RCR. Key findings: Based on the alterations of mRNA levels, the genes might be categorized into three different groups: In the first group, the mRNA levels of the CAT, SOD1 and GSTM3 genes were significantly down-regulated in all examined experimental conditions. In the second group, the mRNA levels of SOD2, NQO1, GSTM2 and GSTO1 were initially increased and then decreased. In the third group, the mRNA levels of NQO2 and GSTP1, were initially increased and then reached to the control levels. The number of down-regulated genes were significantly increased as a function of exposure time (chi(2) = 7.52, P = 0.006). We investigated the effect of morphine (10 mu mol) in the absence and presence of N-acetyl-cysteine (NAC, 1 mmol). The mRNA levels revealed significant differences between cells exposed to morphine and cells co-treated with morphine plus NAC. In cases that morphine increased the level of mRNAs, morphine plus NAC, result in decreased mRNA levels and vice versa. Significance: These findings suggested that there are different pathways for regulation of antioxidant genes after SH-SY5Y cells exposed to morphine and morphine might act through inducing ROS. (C) 2015 Published by Elsevier Inc.