DNMT3A and Familial prostate cancer: Furthermore, Overexpression of miR-340-5p/miR-143-3p/miR-145-5p by miRNA mimics in DU145 and LNcap cells greatly reduced the expression of DNMT3a mRNA and proteins, while knockdown of miR-340-5p/miR-143-3p/miR-145-5p by miRNA inhibitors markedly elevated the DNMT3a mRNA and protein expression in prostate cancer cells (Fig. 5C, D).