Effects of over-expressing or reducing HuR on CD9 and CALM2 expression in MCF-7 cells. A. Western analysis of HuR over-expression in heterogenous population of cells reveals approximately 10% over-expression. B. Lentiviral HuR shRNA efficiently knocks down HuR protein by over 90%. C. HuR over- expression and under-expression results in small changes in CD9 protein levels in MCF-7 cells. D. Levels of both CD9 and CALM2 mRNAs are unchanged in cells which over-express HuR; whereas lentiviral knock-down of HuR in MCF-7 cells results in decreases in steady-state mRNA levels (E). The graph in (F) shows minimal changes in CD9 mRNA and protein levels in HuR over-expressing MCF-7 cells. The CD9 mRNA levels, however, are more affected in HuR knock-down. P value is < 0.005; N.S. = not statistically significant; * = statistically significant.