Influence of oxygen on three different types of telomerized cells derived from a single donor

Three primary cell cultures were derived from a single donor: skin fibroblasts (SF), dennal papilla cells (DP), and mesenchimal stromal cells from lipoaspirate (LA). After a high efficiency introduction of the gene of human telomerase catalytic component (hTERT) in lentiviral construct, we obtained three different strains of immortalized cells. All cells were cultivated in a low oxygen (3%) environment. When telomerized cells were grown in atmospheric conditions (21 % oxygen), growth retardation was observed after a period of 18-40 days. SF-hTERT and DP-hTERT overcame this retardation. In 30-45 days the rate of their growth became as high as it was in 3% oxygen. LA-hTERT cells were incapable to restore the previous growth rate and after several passages ceased proliferation. We found out that telomerized cells were heterogeneous in their ability to form colonies in low density (3 cells per I cm 2): they made 0-9 population doublings in 7 days. At the same time, mean growth rate of SF-hTERT did not change, while the growth of DP-hTFRT and LA-hTERT cells was considerably accelerated in comparison with their growth in mass culture. Transfer of telomerized cells to 2 1 % oxygen reduced their ability to form colonies to a different extent. The total number of cells grown in 2 1 % oxygen was 3 times less than the number grown in 3% oxygen for SF-hTERT and DP-hTERT and 6 times less for LA-hTERT. The original cells (with the exception of LA) were more sensiitive to oxygen level than the telomerized cells. The total number of cells of all three strains (SF, DP LA) grown in 2 1 % oxygen was 6-7 times less. We discuss the reasons of incapability of LA-hTERT cells to adapt to atmospheric oxygen.