The Effect of Telomerase Antisense on the Differentiation of CD34+ Cells from Bone Marrow to Blood Cells.

Background: This study was designed to evaluate the effect of adenovirus-mediated telomerase antisense (TA) expression on cellular proliferation and apoptosis of CD34+ cells in the ex-vivo culture condition collected from normal bone marrow donors.

Methods: We used adenovirus vector containing recombinant antisense telomerase template RNA. Mononuclear cells were obtained from 21 bone marrow donors with normal marrow profile. Each samples were divided into two groups, consisted of the study group treated with telomerase antisense oligonucleotides(TA) and control group without treatment of TA. And then, CD34+ cells were purified from each sample with MACS method and were cultured with LTC-IC method. We evaluated the total and viable cell number, apoptosis degree and blood cell morphology at 2 weeks after LTC-IC culture, and compared between control and experimental groups.

Results: Total cell number of study group (2.3–3.3(median:2.6)X10⁴) was not significantly different from that of control group(2.1–3.5(median:2.7)X10⁴). Viable cell percentage of control and study groups were 71–83(median:76)% and 69–84(median:77)%, respectively, without significant difference. Apoptosis degree of study group (25–38%, median:32%) was significantly higher than that of control (13–27%, median 18%), Blood cell morphology of study group was more differentiated without blast cells (0%) than that of control group showing blast cells (4–9%, median 7%) at 2 weeks of culture.

Conclusion: We found that adenovirus-mediated antisense expression of telomerase RNA might accelerate the differentiation of hematopoietic stem cells with significant effect on the apoptosis degree. Further studies will be warranted to confirm these results and verify the mechanism of these phenomena.