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ABSTRACT: Objective The aim of the research was to study whether microRNA-15a (miR-15a) oligonucleotide could inhibit cell growth and enhance
cytarabine (Ara-C)-induced apoptosis in Raji cells.
Methods Transfecting miR-15a oligonucleotide into Raji cells with Lipofectamine™ 2000, and then combined with Ara-C. IC50 value and cell proliferation were detected by CCK8 assay; the expression levels of Bcl-2 mRNA and protein were evaluated
by RT-PCR and indirect immuno-fluorescence. The apoptotic cells were observed by Hoechst Dyeing; AnnexinV/PI double dyeing
method was used to detect the cell apoptotic rate by Flow Cytometry (FCM).
Results After Raji cells were transfected with miR-15a oligonucleotide for 48 h, Bcl-2 protein expression levels obviously decreased,
however, there was no difference in Bcl-2 mRNA levels, as compared with the control group and blank group (P < 0.05). CCK8 assay showed that miR-15a oligonucleotide decreased the cell growth at 24, 48 and 72 h, moreover, miR-15a oligonucleotides
combined with Ara-C obviously decreased the cell growth than miR-15a group, Ara-C group and scrambled oligonucleotides (SODN)
+ Ara-C group. Meanwhile, miR-15a oligonucleotides combined with Ara-C significantly decreased IC50 of Ara-C (10.41 μg/mL), which were obviously lower than those of Ara-C group (15.43 μg/mL) and SODN plus Ara-C group (14.92
μg/mL). Plenty of apoptotic cells could be seen with Hoechst dyeing. AnnexinV/PI double dying assays by FCM indicated that
the cell apoptotic rates in earlier period and late period of miR-15a + Ara-C group were 20.93% and 25.27%, respectively,
which were obviously higher than those of miR-15a group, Ara-C group and SODN plus Ara-C group.
Conclusion miR-15a oligonucleotides can inhibit cell growth and enhance Ara-C-induced apoptosis in Raji cells.
The Chinese-German Journal of Clinical Oncology 01/2010; 9(5):283-286.