Protein and mRNA expression after CHK1 knowdown. ZhouJun ChenZhengming MalysaAgnes LiXin OliveiraPaula ZhangYingtao BeplerGerold 2013 <p>CHK1 was knocked down using 30 nM ON-TARGET<i>plus</i> SMARTpool siRNA in four gemcitabine-resistant clones and four naturally gemcitabine-resistant cell lines. The mRNA expression ratios were calculated by dividing the gene expression values of CHK1 siRNA transfected cells by those of control siRNA transfected cells. No change in the expression levels of the genes <i>PTEN</i> and <i>MCM7</i> was observed.</p>