MiR-29b reduces cell growth and induces apoptosis in cell lines and primary samples. (A) Cell growth curves of K562 cells (left panel) or Kasumi-1 cells (right panel) transfected or infected in vitro with miR-29a, -29b, and their respective controls (miR-212, scrambled oligonucleotides, or empty vector). (B) Annexin V/PI assays in K562 (left panel) and Kasumi-1 (right panel) cells after 48 hours of transfection with synthetic miR-29b/lentivirus miR-29b or controls (scrambled oligonucleotides, miR-212, or empty vector) in the presence or absence of 5μM of Ara-C. The results are shown as percentage of apoptotic cells. Data are the average of 3 independent experiments ± SD. P values were obtained using t test. *P > .05. (C) Annexin V/PI assays in K562 (left panel) and Kasumi-1 (right panel) cells after 48 hours of transfection with synthetic miR-29a/lentivirus miR-29a or controls (scrambled oligonucleotides, miR-212, or empty vector) in the presence or absence of 5μM of Ara-C. (D) The regulation of apoptosis by miR-29a and -29b was confirmed by measuring caspase 3 or caspase 7 activities. K562 cells were transfected with synthetic miR-29a and -29b or scrambled oligonucleotides and grown in 96-well microplates. After 48 hours, luminescence was measured using the caspase 3 or caspase 7 Glo Assay (Promega). P values were obtained using t test. Values are mean ± SD; n = 3. (E) Pro-caspase 3 protein expression level was measured in K562 by immunoblotting after 48 hours of transfection with synthetic miR-29a and -29b or scrambled oligonucleotides. Loading control was performed using β-actin. (F) Annexin V/PI assays in 2 primary AML samples after 48 hours of transfection with synthetic miR-29b or control (scrambled oligonucleotides) in the presence or absence of 5μM of Ara-C. The results are shown as percentage of apoptotic cells. Bars represent range.