Proinflammatory Cytokines IL-6 and TNF-α Increased Telomerase Activity through NF-κB/STAT1/STAT3 Activation, and Withaferin A Inhibited the Signaling in Colorectal Cancer Cells

Figure 1

STAT3 was activated by IL-6 and TNF-α treatments whereas inhibited by withaferin A in human colorectal cancer cells. (a) Western blot analysis of DLD1 and HT-29 for pSTAT3, total STAT3, pNF-κB, and total NF-κB. Cells were treated with IL-6 (10 ng/ml) and TNF-α (25 ng/ml) alone and in combination for 24 hours, then subjected to protein analysis for pSTAT3, total STAT3, pNF-κB, and total NF-κB. (b) A quantitative graph of pSTAT3: STAT3 ratio was presented from DLD1 and HT-29 (, ). (c) Western blot analysis of DLD1 and HT-29 for pSTAT3, pNF-κB, and Oct-4. Cells were treated with either IL-6 (10 ng/ml) and TNF-α (25 ng/ml) alone or in combination for 24 hours. Withaferin A was treated at 10 μM concentrations for 24 hours as indicated. (d) STAT3 and NF-κB phosphorylation was measured with IL-6 and TNF-α stimulation on a time course. DLD1 cells were treated with combined IL-6 and TNF-α and monitored the phosphorylation status on different time points of 0, 6, 12, and 24 hours.

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