Loss of proliferative capacity in a retroviral immortalized human uterine smooth muscle cell line derived from leiomyoma is restored by hTERT overexpression

Overexpression of human telomerase reverse transcriptase (hTERT) has facilitated establishing in vitro model systems for biological research. The plasmid containing hTERT gene was stably transfected into ULTR cells, a retroviral transformed human uterine leiomyomatous smooth-muscle cell line. Cells that express hTERT, termed as ULTR-hT, shared the morphological characteristics of the parental proliferative ULTR cells. They expressed a set of smooth-muscle-specific genes and had increased proliferation rate and prolonged lifespan. Quantitative real-time polymerase chain reaction (PCR) analysis revealed a correlation of proliferation rates of ULTR-hT clonal cells with the level of hTERT expression. ULTRhT cells also preserved expression of estrogen, progesterone, and oxytocin receptor genes, confirming a myometrial phenotype. Expression of angiotensin II receptors and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase isoforms were also preserved. Our finding suggests that ULTR-hT cells can be a useful in vitro model for studying human myometrium differentiation both in pregnancy and pathological growth.