Characterization of a Bone Marrow Derived Mesenchymal Cell Line from Nude Rat Assembling Tumor Stem/Progenitor Cell Properties In Vitro and In Vivo.

Here we report the in vitro and in vivo properties of a spontaneously transformed nude rat mesenchymal stem cells (rTMSCs) following culture passages 23. When this cell line was compared with early passages of mesenchymal cells (rMSCs) from the same animal, no apparent differences could be seen with regard to the phenotype and Gap junctions’ connexin 43. However, the telomerase activity in rTMSCs is lower than in the rMSCs. Karyotyping of rTMSC gave a trisome 6 phenotype. Microarry analysis of rTMSC shows over expression of the transforming growth factor family including TGF-beta and BMp6. Both rMSC and rTMSC had equal capability to differentiate into adipocytic and “neural like” linage. In contrast rTMSC was unable to differentiate into bone and only this cell line form spheroids in cultures.

Subcutaneously injection of rTMSC in doses down to 2x 104 into nude/nude mice formed tumor in all animals tested. Examination of the tumor assembles morphology like an immature sarcoma. When 100–200 SP + cells were administered to the animals, tumor could also be formed. After intravenous injections and direct injections into left heart ventricle all animals developed metastasis in the lung; abdominal cavity; bone and skin. The rTMSC has been stabled marked with reporter gene GFP and Leucipherase. Currently the proliferation and migration capacity of the linage-differentiated rTMSC is studied in vivo by imaging and these results will be presented. We conclude that our normal and transformed rMSCs could be potential useful for further biological studies on mesenchymal cells both in vitro and in vivo.