The Effect of Telomerase Antisense for the Differentiation of Embryonic Stem Cells to Hemopoietic Stem Cells.

Background: This study was designed to evaluate the effect of adenovirus-mediated telomerase antisense(TA) expression on cellular proliferation and apoptosis of the ex-vivo culture from human embryonic stem cells to hematopoietic stem cells.

Methods: Cultured embryonic stem cell lines (SNU-3 cell line) to hemopoietic stem cells were classified to control and study groups. Control group was that of which embryonic body were cultured to LTC-IC assay not treated with telomerase antisense oligonucleotides(TA). Study group was that of which embryonic body were cultured to LTC-IC assay treated with TA. We evaluated CD34+ cell number and viable cell percentage and the degree of apoptosis of each samples at 5 days after LTC-IC assay and the results were compared between each groups. These studies were tried for 17 times.

Results: The number of CD34+ cells in study group 0.8–2.4(median: 1.5X10³) showed no significant difference with that in control group 0.6–2.9(median: 1.6X10³). Viable cell percentage of control and study groups were 76–89(median: 83) % and 78–90(median: 85) %, respectively, without significant difference. And there was no difference in the degree of apoptosis (absorbance, A_405nm – A_490nm) between control and study groups; 0.092–0.134(median: 0.129) vs 0.087–0.152(median 0.138), with reference to negative control: 0.020, positive control: 0.186. The colony count of CFU-GM in control and study group was 0.1–0.5(medium: 0.3) X10³ and 0.2–0.5(medium: 0.3) X10³, respectively without no significant difference.

Conclusion: We found that adenovirus-mediated antisense expression of telomerase RNA didn’t interrupt the differentiation of embryonic stem cells to hematopoietic stem cells without significant effect on the degree of apoptosis. Further studies will be warranted to confirm these results and verify the mechanism of these phenomena.