Search

Objective: To explore the expression of X-linked inhibitor of apoptosis protein (XIAP) in Tca8113 cell, and to investigate its relationship to the chemoresistance. METHODS; The Tca8113 cell line was cultured by IMDM and the concentration of Pingyangmycin (PYM) added to Tca8113 cell line was increased gradually and continually, which was to induce the PYM-resistance in Tca8113 cell line. The sensitivity of Tca8113 cell to PYM and expression of XIAP were measured with methyl thiazolyl tetrazolium (MTT) chromatometry and reverse transcription-polymerase chain raction (RT-PCR). The XIAP level in the cells and its chemoresistance to PYM were analyzed by linear regression., Results: The IC50 of Tca8113-1-10 group and Tca8113-10-10 group were(12.758 +/- 0.030), (18.986 +/- 0.150) microg x mL(-1) respectively. The IC50 of Tca8113-1-20 group and Tca8113-10-20 group increased to (26.302 +/- 0.072), (35.294 +/- 0.115) microg x mL(-1) respectively. There was a relation between XIAP and the drug-resistance in Tca8113 cell., Conclusion: XIAP may play an important role in the chemoresistance which might serve as a new therapeutic target for oral squamous cell carcinoma.

Severe hypoglycemia has a detrimental impact on the cerebrovasculature, but the molecular events that lead to the disruption of the integrity of the tight junctions remain unclear. Here, we report that the microvessel integrity was dramatically compromised (59.41% of wild-type mice) in TP53-induced glycolysis and apoptosis regulator (TIGAR) transgenic mice stressed by hypoglycemia. Melatonin, a potent antioxidant, protects against hypoglycemic stress-induced brain endothelial tight junction injury in the dosage of 400 nmol/L in vitro. FRET (fluorescence resonance energy transfer) imaging data of endothelial cells stressed by low glucose revealed that TIGAR couples with calmodulin to promote TIGAR tyrosine nitration. A tyrosine 92 mutation interferes with the TIGAR-dependent NADPH generation (55.60% decreased) and abolishes its protective effect on tight junctions in human brain microvascular endothelial cells. We further demonstrate that the low-glucose-induced disruption of occludin and Caludin5 as well as activation of autophagy was abrogated by melatonin-mediated blockade of nitrosative stress in vitro. Collectively, we provide information on the detailed molecular mechanisms for the protective actions of melatonin on brain endothelial tight junctions and suggest that this indole has translational potential for severe hypoglycemia-induced neurovascular damage. [ABSTRACT FROM AUTHOR]