An investigation of Patched function in adult skeletal muscles (360G-Wellcome-211445_Z_18_Z)

The cancer stem cell (CSC) theory postulates that skeletal muscle-specific cancers known as Rhabdomyosarcomas (RMS) result and recur due to a subpopulation of cancerous cells sharing stem cell-like properties including the ability to self-renew and proliferate. Building on previous work implicating Sonic hedgehog (Shh) signalling in muscle regeneration, this study will investigate the ability of adult skeletal muscle satellite cells (SC) to self-renew, following conditional knockout of Patched (Ptc), a tumour suppressor gene mutated in RMS. It is expected that upregulation of Shh signalling will deregulate SC behaviour, contributing to their transformation into CSCs, thus leading to RMS. Mice deficient for Ptc exclusively in SCs, produced using an inducible Cre-Recombinase under the control of the Pax7 promoter, will be used. Following induction of recombination, mice will be subjected to repeated injuries by unilateral injection of Cardiotoxin into the Tibialis Anterior muscle at intervals of 21 days. After the 3rd injury, muscles will be harvested and analysed by immunofluorescence to determine the effect of Ptc loss-of-function on SC self-renewal. This study will determine whether SCs give rise to CSCs when Shh signalling is disturbed, and contribute to RMS. This knowledge is crucial for designing novel therapies for the treatment of RMS.