MAPK signalling in skeletal muscle-derived stem cells after daunorubicin treatment

Long-term muscle-derived cell culture: multipotency and susceptibility to cell death stimuli

Improvement in the yield of adult organism stem cells, and the ability to manage their differentiation and survival potential are the major goals in their application in regenerative medicine and in the adult stem cell research. We have demonstrated that adult rabbit muscle-derived cell lines with an unlimited proliferative potential in vitro can differentiate into myogenic, osteogenic, adipogenic and neurogenic lineages. Studies of cell survival in vitro showed that differentiated cells, except neurogenic ones, are more resistant to apoptosis inducers compared to proliferating cells. Resistance to death signals correlated with the level of protein kinase AKT phosphorylation. Skeletal muscle-derived cell lines can be multipurpose tools in therapy. Enhanced resistance of differentiated cells to certain types of damage shows their potential for long-term survival and maintenance in an organism. This article was published online on 29 January 2013. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 6 March 2013.

Daunorubicin induces cell death via activation of apoptotic signalling pathway and inactivation of survival pathway in muscle-derived stem cells

Daunorubicin (as well as other anthracyclines) is known to be toxic to heart cells and other cells in organism thus limiting its applicability in human cancer therapy. To investigate possible mechanisms of daunorubicin cytotoxicity, we used stem cell lines derived from adult rabbit skeletal muscle. Recently, we have shown that daunorubicin induces apoptotic cell death in our cell model system and distinctly influences the activity of MAP kinases. Here, we demonstrate that two widely accepted antagonistic signalling pathways namely proapoptotic JNK and prosurvival PI3K/AKT participate in apoptosis. Using the Western blot method, we observed the activation of JNK and phosphorylation of its direct target c-Jun along with inactivation of AKT and its direct target GSK in the course of programmed cell death. By means of small-molecule kinase inhibitors and transfection of cells with the genes of the components of these pathways, c-Jun and AKT, we confirm that JNK signalling pathway is proapoptotic, whereas AKT is antiapoptotic in daunorubicin-induced muscle cells. These findings could contribute to new approaches which will result in less toxicity and fewer side effects that are currently associated with the use of daunorubicin in cancer therapies.