Comparative Assessment of Cultures from Oral and Urethral Stem Cells for Urethral Regeneration.

Urethral reconstruction has received much attention in recent years, due to pathologies such as recurrence of urethral strictures after treatments. Various surgical techniques have been developed to obtain the best risk-benefit ratio, such as autologous grafts taken from the oral cavity. Tissue engineering and stem cells, growing in a tissue from a small biopsies, can further improve surgery, reducing invasiveness and morbidity. To determine whether urethra or other epithelia can be equally useful for urethra engineering, a comparison of clonogenic ability, proliferative potential and stem cell markers should be obtained. In this study, 19 biopsies from urethra, and 21 from oral mucosa were obtained from patients, during reconstructive surgery. Urethral and oral tissues were removed from the same donor, to develop primary cultures and cell characterization. The long term regenerative properties of both tissues were investigated in vitro by life span, clonal analysis and markers of different clonal types. Results revealed the same high proliferative potential for urethra and oral mucosa cultures, but maintenance of specific markers. Karyotype and growth factor dependence confirmed the normal phenotype of cultured cells. Clonal analysis of the proliferative compartment highlighted a very different proportion of stem and transient amplifying cells, characterised by dissimilar cell size profile and marker expression. In conclusion, both tissues can be cultured and preserve their stem cells in vitro. Few differences appeared in oral mucosa vs urethra, suggesting that they can be equally useful for tissue engineering of the urethral tract.

Hsp60 is actively secreted by human tumor cells.

BACKGROUND: Hsp60, a Group I mitochondrial chaperonin, is classically considered an intracellular chaperone with residence in the mitochondria; nonetheless, in the last few years it has been found extracellularly as well as in the cell membrane. Important questions remain pertaining to extracellular Hsp60 such as how generalized is its occurrence outside cells, what are its extracellular functions and the translocation mechanisms that transport the chaperone outside of the cell. These questions are particularly relevant for cancer biology since it is believed that extracellular chaperones, like Hsp70, may play an active role in tumor growth and dissemination. METHODOLOGY/PRINCIPAL FINDINGS: Since cancer cells may undergo necrosis and apoptosis, it could be possible that extracellular Hsps are chiefly the result of cell destruction but not the product of an active, physiological process. In this work, we studied three tumor cells lines and found that they all release Hsp60 into the culture media by an active mechanism independently of cell death. Biochemical analyses of one of the cell lines revealed that Hsp60 secretion was significantly reduced, by inhibitors of exosomes and lipid rafts. CONCLUSIONS/SIGNIFICANCE: Our data suggest that Hsp60 release is the result of an active secretion mechanism and, since extracellular release of the chaperone was demonstrated in all tumor cell lines investigated, our observations most likely reflect a general physiological phenomenon, occurring in many tumors.