Immortalized Human Endometrial Stromal Cells (HESC)

The endometrium undergoes dynamic cyclic remodeling, in which endometrial stromal cells (ESCs) differentiate into secretory decidual cells under the influence of ovarian steroids-a process essential for embryo implantation and pregnancy establishment. However, primary human ESCs present considerable experimental limitations: they are hampered by the scarcity of adequate human tissue and possess a limited proliferative capacity, undergoing rapid dedifferentiation and senescence after only a finite number of passages. These constraints severely restrict long-term, high-throughput mechanistic investigations. To circumvent these obstacles, immortalized human ESC lines have been established through the stable transduction of human telomerase reverse transcriptase (hTERT).

These immortalized human ESC lines offer the following distinct advantages: (1) maintenance of a normal diploid karyotype without clonal chromosomal structural or numerical abnormalities; (2) preservation of classical decidualization responsiveness to estradiol and medroxyprogesterone acetate, including the secretion of prolactin (PRL), insulin-like growth factor binding protein-1 (IGFBP-1), tissue factor (TF), and plasminogen activator inhibitor-1 (PAI-1); (3) retention of stromal lineage markers (vimentin, CD90) while remaining negative for epithelial markers; (4) phenotypic and functional stability sustained for many passages (e.g., >150 passages for St-T1b); and (5) absence of tumorigenic potential, as demonstrated in nude mouse models.

Collectively, immortalized human ESCs provide a consistent, reproducible, and phenotypically faithful in vitro model for investigating endometrial physiology, hormone-mediated decidualization, the pathogenesis of endometriosis and endometrial cancer, and drug screening, while circumventing the material limitations and passage constraints inherent to primary cell cultures.