Effects of artificial microRNA targeting glucosylceramide synthase on drug sensitivity of breast cancer cells

To explore the inhibitory effects on glucosylceramide synthase (GCS) expression and drug sensitivity in breast cancer cells by transfecting artificial microRNA targeting GCS. Two microRNA expression vectors targeting GCS were constructed and transfected into MCF-7/ADR cells via Lipofectamine 2000. The levels of GCS mRNA and protein were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot respectively. Methyl thiazolyl tetrazolium (MTT) assay was used to assess the chemosensitivity of MCF-7/ADR cells to adriamycin (ADM) and vincristine. After transfection of two microRNA expression vectors, the expression of GCSmRNA in MCF-7/ADR cells was 0.098 ± 0.005 and 0.143 ± 0.007 respectively. Compared with the control cells (0.875 ± 0.008), the difference was significant (P < 0.01). The expression of GCS protein (0.127 ± 0.004, 0.165 ± 0.008) in MCF-7/ADR cells was lower than that in the control cells (0.765 ± 0.007; P < 0.01). Furthermore, in comparison with the control cells, the res