Evaluation of Morpholino Antisense Oligo's Role on BCR-ABL Gene Silencing in the K562 Cell Line

Chronic myeloid leukemia (CML) develops when a hematopoietic stem cell acquires the BCR/ABL fusion gene. This causes these transformed hematopoietic cells to have a greater than normal proliferation rate. Scientists attempt to improve the CML treatment process by silencing the BCR/ABL oncogene. In this work, we used morpholino antisense oligos to silence the BCR/ABL oncogene. In this study, the K562 was used as a BCR/ABL fusion-gene positive cell line and the Jurkat cell line as a control. We explored the inhibiting capacity of morpholino antisense oligos in the the expression of the BCR/ABL oncogene and studied their p210 BCR/ABL suppression, inhibition of cell proliferation and stimulation of apoptosis in the K562 cells after 24 and 48 hours. Endo-Porter was used for delivery ofmorpholino antisense oligos into cell cytosols. Meanwhile, flow cytometric analysis wasperformed in order to determine the appropriate concentration of morpholino antisenseoligos. Prolonged exposure of the K562 cell line to the morpholino antisense oligos targeted against the BCR-ABL gene showed proliferation inhibition as its main feature. After western blotting, we found that complete silencing of BCR/ABL was achieved, but flow cytometric analysis showed no broad apoptosis. The results indicate that the Morpholino antisense oligo is able to inhibit p210 BCR/ABL; however, it cannot induce broad apoptosis due to co-silencing of BCR.