Immortalized Human Bone Marrow-Derived Mesenchymal Stem Cells-SV40 (Tet-on)

Immortalized human bone marrow-derived mesenchymal stem cells (BM-MSCs) were established via stable introduction of the Simian Virus 40 large T antigen (SV40T), which inactivates p53- and pRB-dependent cell cycle checkpoints, thereby bypassing replicative senescence and enabling continuous proliferation. The incorporation of the Tet-on inducible expression system (reverse tetracycline-controlled transactivator) provides an additional layer of experimental control. In this system, gene expression of interest is tightly regulated by doxycycline, allowing precise temporal induction or repression of transgenes. This feature is particularly valuable for studying dose-dependent or time-sensitive gene functions without the confounding effects of constitutive expression.

Key advantages of this cell line include: (1) unlimited proliferative capacity while maintaining typical MSC morphology (fibroblast-like, adherent); (2) preservation of surface marker profile (CD73+, CD90+, CD105+, CD14-, CD34-, CD45-); (3) retention of multilineage differentiation potential into osteocytes, chondrocytes, and adipocytes under appropriate inductive conditions; (4) genomic stability without tumorigenicity in immunodeficient hosts; (5) Tet-on inducibility enabling conditional gene expression studies; and (6) batch-to-batch consistency eliminating primary culture variability.

Collectively, Immortalized Human BM-MSCs-SV40 (Tet-on) provide a robust, reproducible, and versatile in vitro platform for mechanistic studies of MSC biology, bone and cartilage regeneration, gene function analysis, and high-throughput drug screening, circumventing the inherent limitations of primary MSCs.