Role of TRPM2 ion channel,an oxidative stress sensor,in hyperglycemiainduced pro-inflammaotry IL-1β in human monocytes

OBJECTIVE To investigate the role of transient receptor potential melastatin 2(TRPM2),a calcium-permeable non-selective cation channel which acts as an oxidative stress sensor,in mediating the production of pro-inflammatory IL-1βin high glucose condition.METHODS Human pro-monocytic leukemia cell U937 was purchased from ATCC and cultured in RPMI 1640(Life Technologies).Prior to high glucose(HG)stimulation,U937 cells were cultured in medium with glucose 5.5mmol·L-1 for 48 h.The cells were then incubated in high glucose concentration(30mmol·L-1)or mannitol(30mmol·L-1)for 48 h.The protein expression of TRPM2 and the production of human IL-1β were evaluated by ELISA.TRPM2 inhibitors(DPQ and AMP)and TRPM2 siRNAs were employed to further investigate the role of TRPM2 in HG-induced IL-1β production.RESULTS The TRPM2 protein expression was significantly up-regulated by 2-folds in U937 cells after the treatment of high glucose(30mmol·L-1 for 48h)(P<0.01).The production of IL-1β in U937 was also significantly increased by HG treatment and was time-and dose-dependent(10,20 or 30mmol·L-1 glucose for 24,48 or 72h)(P<0.01).The HG-induced IL-1β production in U937 could be abolished by using TRPM2 inhibitors DPQ(100μmol·L-1 for 45min)and AMP(100μmol·L-1 for 45 min)as well as by the transfection of TRPM2siRNAs(60nmol·L-1).CONCLUSION High glucose condition(such as in diabetes)might mediate pro-inflammatory environments via the modulation of TRPM2 channels on immune cells.

A Preliminary Study on Anti-Colorectal Cancer Effect and Molecular Mechanism of Aegiceras Corniculatum Extract

Objective:To study the inhibitory effects on colorectal cancer(CRC)and the underlying mechanism of the petroleum ether extract of Aegiceras corniculatum leaves(PACL).Materials and Methods:The effect of PACL on the proliferation of CRC cell lines DLD-1,HT-29,and SW480was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and colony-forming assay.And then,a wound-healing assay was used to measure the migration ability of three CRC cells.The cell cycle and apoptosis of three CRC cells were measured by PI/RNase staining and annexin V-FITC/double staining,respectively,and the intrinsic apoptosis pathway was studied by the Western blot.The anti-CRC effect of PACL in vivo was evaluated by HT-29 xenograft zebrafish embryos.Results:PACL inhibited cell viability and proliferation in DLD-1,HT-29,and SW480 cells in a dose-and time-dependent manner.PACL can inhibit cell migration in DLD-1and SW480 cells but not in the less mobile phenotype cell HT-29.PACL treatment resulted in cell cycle arrest of DLD-1 and HT-29 cells in the G2/M phase.Moreover,PACL can induce apoptosis in all three CRC cells,which may be achieved by regulating the intrinsic apoptosis pathway mediated by mitochondria and the endoplasmic reticulum.Interestingly,the tumor sizes were decreased after treatment with PACL and PACL combined with fluorouracil in HT-29 xenograft zebrafish embryos.Conclusions:These findings suggested that PACL may exert its anti-CRC effect by inducing apoptosis through the intrinsic apoptosis pathway and show a significant anti-CRC effect in vitro and in vivo,so it might be potentially developed as an anti-CRC agent.