shRNA against CD44 inhibits cell proliferation, invasion and migration, and promotes apoptosis of colon carcinoma cells

CD44 is a causal factor for tumor invasion, metastasis and acquisition ofresistance to apoptosis. CD44 knockdown using inducible short hairpin RNA (shRNA)significantly reduces cell growth and invasion. Short hairpin RNA against CD44and pGFP-V-RS-vector was used for knockdown of CD44 expression in SW620 coloncancer cells. Cell growth, invasion and migration assay, immunofluorescence forβ-catenin expression and western blotting for Wnt signaling molecules were analyzed.Cell cycle analysis and western blot analysis for apoptotic molecules were evaluated.Short hairpin RNA against CD44 reduced the expression of CD44. Cell proliferation,migration and invasion were markedly inhibited and apoptosis was increased inshRNA CD44-transfected cells. Knockdown of CD44 decreased the phosphorylationof PDK1, Akt and GSK3β, and β-catenin levels. Decreased phosphorylated Akt ledto an increase in phosphorylated FoxO1 and induced cell cycle arrest in the G0-G1phase and a decrease in the S phase. The levels of Bcl-2 and Bcl-xL expressionwere down-regulated, while the levels of BAX expression and cleaved caspase-3,-8 and -9 were increased. CD44 knockdown by way of shRNA inhibited cell proliferationand induced cell apoptosis. This can be used as a therapeutic intervention withthe anti-survival/pro-apoptotic machinery in human colon cancer.