Restoration of miR-34 chemosensitizes Kato III cells with high Bcl-2, but not MKN-45 cells with low Bcl-2. MTT-based cytotoxicity assay of Kato III (A) and MKN-45 (B) cells transfected with miR-34a mimic or control mimic. The cells were transfected with miR-34a or NC mimics by Lipofectamine 2000. 24 hr later, the cells were trypsinized and plated in 96-well plates and treated with the indicated chemotherapeutic agents in triplicate. The MTT-based WST-1 assay was carried out on Day 4. Restoration of miR-34a in Kato III cells with high Bcl-2 rendered the cells 2-3-fold more sensitive to chemotherapies, but had no effect on MKN-45 cells with low Bcl-2. 34a, miR-34a mimic; NC, non-specific control miRNA mimic.