Cis-4-hydroxy-l-proline and ethyl-3,4-dihydroxybenzoate prevent myogenesis of C2C12 muscle cells and block myoD1 and myogenin expression

cis-4-Hydroxy-l-proline (cis-OH-Pro) and ethyl-3,4-dihydroxybenzoate (EDHB), two distinct inhibitors of collagen synthesis, prevented myogenesis in C2C12 mouse skeletal muscle cells. Both inhibitors blocked myotube formation and the expression of sarcomeric myosin heavy chain. Northern blot analysis showed that cis-OH-Pro- and EDHB-treated C2C12 muscle cells did not express the myogenic regulatory genes, MyoD1 and myogenin, but continued to express nonmuscle isoforms of actin (β and γ) and α-tropomyosin. 10TFL2-3B cells, a C3H10T1/2 cell line permanently transfected with myogenin cDNA, constitutively expressed exogenous myogenin in the presence of cis-OH-Pro but failed to activated endogenous myogenin and to undergo myogenesis. These results demonstrate that commitment to terminal differentiation and activation of myogenic regulatory genes requires active synthesis of the extracellular matrix component collagen.