Fig. 2: SIRT1 upregulation is mediated by c-Myc downstream of KRAS.
From: Oncogenic KRAS mutation confers chemoresistance by upregulating SIRT1 in non-small cell lung cancer
A HEK293T cells were transfected with pcDNA and KRASG12C plasmids (2 μg). H460 cells were transfected with siCon and siKRAS (80 nM). The cells were harvested with lysis buffer and subjected to western blotting. B, C KRASMut cells (H358, NCIH23, SKLU-1, SW900, A427, H727), KRASWT cells, and KRASG12C cells (H1299G12C) were transfected with siCon, c-Myc specific siRNA (80 nM), pcDNA, or c-Myc plasmid (2 μg) for 48 h, and the levels of the KRAS downstream effectors c-Myc and SIRT1 were measured. D H358 cells were transfected with KRASG12C and siCon or sic-Myc, and cell extracts were immunoprecipitated with an anti-KRAS antibody and immunoblotted with anti-SIRT1, anti-c-Myc, and anti-KRAS antibodies. E Chromatin immunoprecipitation-qPCR analysis of KRAS, SIRT1, and SIRT2 was performed in H358 cells transfected with siCon or siKRAS (80 nM) for 48 h and then immunoprecipitated using an anti-c-Myc antibody or mouse IgG as a negative control. The relative enrichment was calculated by normalizing the qPCR signals. The data are plotted as the mean values determined from at least two independent chromatin immunoprecipitation assays and three independent amplification reactions. Student’s t test, mean ± SD; n = 6; *p < 0.05. F H358 cells were transfected with siCon and siKRAS (80 nM) for 48 h and then fixed after 4 h. c-Myc expression was detected with an RFP emission filter, and SIRT1 expression was detected with a GFP emission filter.
