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Objective:To investigate the effect of epidermal growth factor receptor tyrosine kinase inhibitor on the radiosensitivity of human non-small cell lung cancer cells and its possible mechanism.Methods:Human non-small cell lung cancer cells H1299 were cultured in vitro. CCK-8 was used to detect the toxic effects of erlotinib on H1299 cells, IC 50 and IC 20 were calculated, and IC 20 was utilized as the drug concentration for subsequent experiments. The colony formation assay was performed to identifiy the effect of X-ray combined with erlotinib on H1299 cells, the radiosensitivity parameters were calculated, and the cell survival curves were delineated. Flow cytometry was conducted to detect the cell cycle distribution and apoptosis. Western blot analysis was used to detect the expression of EGFR/PI3K/AKT pathway and apoptosis-related proteins. Results:Erlotinib exerted inhibitory effect upon the proliferation of H1299 cells, IC 50 was calculated as 27.3 μmol/L, and 3.3 μmol/L for IC 20. X-ray combined with IC 20 concentration of erlotinib could reduce the cloning ability of H1299, increased the proportion of G 0/G 1 phase and G 2/M phase, decreased the proportion of S phase, aggravated cell apoptosis, down-regulated the expression of pEGFR and pAKT proteins, and up-regulated the expression of apoptosis-related proteins including Active Caspase 3 and Cleaved PARP. Conclusions:Erlotinib exerts a radiosensitizing effect on H1299. The possible mechanism is that erlotinib combined with radiation can suppress the EGFR/PI3K/AKT pathway, reduce the ability of repairing cell damage, change cell growth cycle and induce cell apoptosis.
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Human epidermal growth factor receptor (HER)-2-positive breast cancer is a type of highly invasive breast cancer with a high recurrence rate. Although the single-targeted treatment for HER-2 prolongs survival, patients still develop recurrence and metas-tasis. The mechanisms of dual-targeted therapies are non-overlapping and have synergistic effects, which further improves the survival of patients. Based on trastuzumab, this article reviews the current status and progression indual-targeted therapeutic regimens con-taining anti-HER-2.
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AIM: To investigate the effects of sodium hydrosulfide ( NaHS ) , a donor of hydrogen sulfide ( H2 S) , on the membrane permeability , intracellular Ca 2+concentration ( [ Ca2+] i ) and the release of IL-1βinduced by a-denosine triphosphate (ATP) in rat microglia, and to explore the effect of H2S on ATP-P2X purinergic signaling pathway and the molecular mechanism of its neuroprotective effect .METHODS: Rat microglia in logarithmic growth phase were used in the study.The [Ca2+]i was detected by Fura-2/AM staining.Fluorescent dye YO-PRO-1 was used to observe the membrane permeability.Interleukin-1β(IL-1β) was measured by rat IL-1βELISA kits.RESULTS:The YO-PRO-1 flu-orescence intensity was obviously elevated by ATP induction in a dose -dependent manner in the rat microglia , but this effect was counteracted by NaHS pretreatment (P<0.05).[Ca2+]i rapidly increased and then decreased slowly , forming a sta-ble platform for a long time when rat microglia were treated with ATP .Ca2+spike activity induced by ATP had no change , but the platform disappeared (P<0.05) after NaHS pretreatment.The ATP and LPS together facilitated the release of IL-1β, but the phenomenon was inhibited by NaHS (P<0.05).CONCLUSION:Hydrogen sulfide may decrease the mem-brane permeability , calcium inflow and IL-1βrelease in rat microglia activated by high dose of ATP .The cytoprotection of hydrogen sulfide may be mediated by purinergic signaling pathway .
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AIM: To examined the effects of hypoxic preconditioning ( HPC) on oxygen-glucose deprivation ( OGD)-induced PC12 cells, and to investigate its possible mechanisms of autophagy .METHODS: Cultured PC12 cells were randomly divided into control group , HPC group, 3-methyladenine (3-MA) group, HPC+OGD group, 3-MA+HPC+OGD group and OGD group .CCK-8 assay was used to detect the cell viability .The caspase-3 activity was also tested . TUNEL staining and flow cytometry were used to detect the cell apoptosis .The protein levels of apoptosis-related protein caspase-3 and autophagy-marked protein LC3-2 and beclin-1 were determined by Western blot .RESULTS:Compared with control group, the viability of PC12 cells was significantly reduced , and the activity of caspase-3 was significantly increased in OGD group.Compared with 3-MA+HPC+OGD group and OGD group , the viability of PC12 cells was significantly in-creased, and the activity of caspase-3 was significantly reduced in HPC +OGD group (P<0.05).The PC12 cell injury was apparent after OGD with a great increase in the apoptotic rate (P<0.05).Compared with OGD group, the apoptotic rate significantly decreased in HPC +OGD group ( P<0.05 ) .Compared with control group , the protein level of cleaved caspase-3 was significantly increased in OGD group ( P<0.05) .Compared with OGD group , the protein level of cleaved caspase-3 was significantly decreased , and the levels of LC3-2 and beclin-1 were significantly increased in HPC +OGD group (P<0.05).CONCLUSION:OGD decreases cell survival and induces apoptosis .Activation of cell autophagy may be the mechanism by which hypoxic preconditioning protects the PC 12 cells from OGD induced injury .
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[ABSTRACT]AIM:ToexaminetheeffectsofhighconcentrationofextracellularATPonhumanneuroblastoma SH-SY5Y cell injury.METHODS: Cultured SH-SY5Y cells were grouped according to the concentrations of ATP and treatment time.The cell viability was detected by CCK-8 assay.The variation of autophagic vacuoles was observed with monodansylcadaverine staining .The cell apoptosis was analyzed by Hoechst 33258 staining.Meanwhile, apoptotic rate was detected by flow cytometry .The levels of caspase-3 and microtubule-associated protein 1 light chain 3-Ⅱ ( LC3-Ⅱ) were determined by Western blotting .RESULTS:Compared with control group , the survival rate of SH-SY5Y cells was signifi-cantly reduced by ATP at different concentrations (3, 6, 9, 12 and 15 mmol/L for 3 h) and different treatment time (1, 2, 3 and 6 h with 6 mmol/L ATP, peaking at 3 h).The autophagic vacuoles of SH-SY5Y cells were significantly increased at 1 h with ATP treatment , trended to decrease over time and returned to control level at 6 h.The protein expression of LC3-Ⅱwas significantly increased at 1 h with ATP treatment , which was consistent with the time points of increasing auto-phagic vacuoles .LC3-Ⅱexpression level gradually decreased at 2~3 h with ATP treatment , and returned to control level at 6 h.Compared with control group , the apoptotic rate and the expression level of caspase-3 were enhanced synchronously . The peak of apoptotic rate occurred at 3 h, and kept until 6 h.The level of cleaved caspase-3 expression peaked at 6 h. CONCLUSION:High concentration of extracellular ATP induces the autophagy and apoptosis of SH -SY5Y cells.The in-creased autophagy shows up , followed by the climax of apoptosis until 6 h.With the prolonged duration of ATP , apoptosis is the main process in the cells .
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Aim To investigate the protective effects of hydrogen sulfide ( H2 S) on focal cerebral ischemia/reperfusion injury in rats and the possible mechanisms. Methods Male Sprague Dawley rats were divided into three groups randomly: sham-operated group, cerebral ischemia/ reperfusion ( I/R) group and sodium hydro-sulfide ( NaHS ) + I/R group. The left temporary middle cerebral artery occlusion ( MCAO ) model was established by the line-embolism method. After rats were suffered 2h/24h ischemia/reperfusion stress, the mortality rate was evaluated, and the nervous function-al defect degree was evaluated by Longe scoring, the volumes of cerebral infarction was evaluated by 2 ,3 ,5-triphenyltetrazolium chloride ( TTC) staining, and the expression of P2X7 receptor protein in brain tissue was detected by the immunofluorescence method. Results The mortality rate in NaHS + I/R rats ( 29.41%) was obviously lower than those of I/R group ( 42 . 86%) . The nervous defect scores in NaHS + I/R rats were significant lower than those of I/R group ( P <0.05 ) . The volumes of cerebral infarction in NaHS +I/R group (21.88% ±3.53%) were significant lower than those of I/R group ( 36.71% ±3.73%) ( P <0.01 ) . The results of immunofluorescence showed that the positive expression cells of P2X7 receptor protein in cerebral cortex and hippocampal CA1 area of I/R group were significantly higher than those of sham-op-erated group(P<0. 01). However, compared with I/R group, the positive expression cells of P2X7 receptor protein in cerebral cortex and hippocampal CA1 area of NaHS + I/R group were significantly decreased ( P<0. 01). Conclusions H2S exerts the neuroprotective effect on focal cerebral ischemia/reperfusion injury in rats, and the protective mechanism might be associated with down-regulating the expression of P2X7 receptor protein in brain tissue.