Background Tumor hypoxia, one of the features of solid tumors, is associated with chemo-resistance. Recently, nuclear factor-KB （NF-κB） was found to be activated during hypoxia. However, the impact of NF-κB activa...Background Tumor hypoxia, one of the features of solid tumors, is associated with chemo-resistance. Recently, nuclear factor-KB （NF-κB） was found to be activated during hypoxia. However, the impact of NF-κB activation on chemo-resistance during hypoxia remains unknown. Methods Human lung adenocarcinoma A549 cells were transfected with NF-κB p65siRNA and treated with cobalt chloride （COCI2） to mimic hypoxia in the presence or absence of cisplatin. NF-KB expression was measured by Western blotting, immune-fluorescence and real-time PCR. Hypoxia-inducible factor-1α （HIF-1α） and Bcl-2 expression were determined by Western blotting. Cell apoptosis and survival with half-maximum inhibitory concentration （IC50） of cisplatin were determined by Annexin V-FITC/PI and 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （MTT）, respectively. Results Exposure ofA549 cells to COCl2 increased nuclear HIF-1α protein expression, and enhanced NF-KB p65 protein nuclear accumulation （the mark of NF-κB activation） in a time and dose dependant manner. COCI2 did not promote apoptosis in A549 cells; on the contrary, it reduced cisplatin-induced apoptosis and increased the IC50 of cisplatin. However, when we inhibited CoCI2-induced activation of NF-κB through NF-κB p65siRNA, cisplatin-induced apoptosis was increased and IC50 of cisplatin was reduced to levels similar to those in control cells. Meanwhile, CoCI2-induced Bcl-2 over- expression was down-regulated in the presence of cisplatin when NF-κB activity was inhibited. Conclusion Up-regulating Bcl-2 might be involved in NF-κB activation induced resistance to cisplatin in A549 cells under CoCl2-induced chemical hypoxia.展开更多
Phytochemical investigations from the roots of Cynanchum stauntonii led to obtain four new C_（21） steroidal glycosides（1–4） and one known compound stauntoside F（5）. Their chemical structures were characterized ...Phytochemical investigations from the roots of Cynanchum stauntonii led to obtain four new C_（21） steroidal glycosides（1–4） and one known compound stauntoside F（5）. Their chemical structures were characterized by sophisticated analyses of IR, HRESI-TOF-MS, 1D, and 2D-NMR data, together with chemical methods, which showed interesting 13,14：14,15-disecopregnane-type skeleton or 14,15-secopregnane-type skeleton C_（21） steroidal glycosides. Among them, compound 1 was determined to be glaucogenin C 3-O-b-D-glucopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-thevetopyranoside. Compound 2 was characterized to be hirundigenin 3-O-a-L-diginopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-30-demethyl-thevetopyranoside. Compound 3 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-oleandropyranoside.Compound 4 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-Dthevetopyranoside. Among them, compound 2 was hirundigenin type C21 steroidal glycoside that existed in nature as epimers due to the presence of 14-hemiketal hydroxyl group in its structure. In addition, the anti-inflammatory and cardiomyocyte protective effects of compounds 1–4 were evaluated. We found that they exhibited significant protective effects on hypoxia/reoxygenation induced cardiomyocyte injury, but did not showed obvious anti-inflammatory function.展开更多
文摘Background Tumor hypoxia, one of the features of solid tumors, is associated with chemo-resistance. Recently, nuclear factor-KB （NF-κB） was found to be activated during hypoxia. However, the impact of NF-κB activation on chemo-resistance during hypoxia remains unknown. Methods Human lung adenocarcinoma A549 cells were transfected with NF-κB p65siRNA and treated with cobalt chloride （COCI2） to mimic hypoxia in the presence or absence of cisplatin. NF-KB expression was measured by Western blotting, immune-fluorescence and real-time PCR. Hypoxia-inducible factor-1α （HIF-1α） and Bcl-2 expression were determined by Western blotting. Cell apoptosis and survival with half-maximum inhibitory concentration （IC50） of cisplatin were determined by Annexin V-FITC/PI and 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （MTT）, respectively. Results Exposure ofA549 cells to COCl2 increased nuclear HIF-1α protein expression, and enhanced NF-KB p65 protein nuclear accumulation （the mark of NF-κB activation） in a time and dose dependant manner. COCI2 did not promote apoptosis in A549 cells; on the contrary, it reduced cisplatin-induced apoptosis and increased the IC50 of cisplatin. However, when we inhibited CoCI2-induced activation of NF-κB through NF-κB p65siRNA, cisplatin-induced apoptosis was increased and IC50 of cisplatin was reduced to levels similar to those in control cells. Meanwhile, CoCI2-induced Bcl-2 over- expression was down-regulated in the presence of cisplatin when NF-κB activity was inhibited. Conclusion Up-regulating Bcl-2 might be involved in NF-κB activation induced resistance to cisplatin in A549 cells under CoCl2-induced chemical hypoxia.
基金supported by grants from Science and Technology Planning Project of Guangdong Province,China(No.2015B030301005)
文摘Phytochemical investigations from the roots of Cynanchum stauntonii led to obtain four new C_（21） steroidal glycosides（1–4） and one known compound stauntoside F（5）. Their chemical structures were characterized by sophisticated analyses of IR, HRESI-TOF-MS, 1D, and 2D-NMR data, together with chemical methods, which showed interesting 13,14：14,15-disecopregnane-type skeleton or 14,15-secopregnane-type skeleton C_（21） steroidal glycosides. Among them, compound 1 was determined to be glaucogenin C 3-O-b-D-glucopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-thevetopyranoside. Compound 2 was characterized to be hirundigenin 3-O-a-L-diginopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-30-demethyl-thevetopyranoside. Compound 3 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-oleandropyranoside.Compound 4 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-Dthevetopyranoside. Among them, compound 2 was hirundigenin type C21 steroidal glycoside that existed in nature as epimers due to the presence of 14-hemiketal hydroxyl group in its structure. In addition, the anti-inflammatory and cardiomyocyte protective effects of compounds 1–4 were evaluated. We found that they exhibited significant protective effects on hypoxia/reoxygenation induced cardiomyocyte injury, but did not showed obvious anti-inflammatory function.
