LIGHT is a member of the tumor necrosis factor (TNF) superfamily, which binds two known receptors, lymphotoxin-beta receptor (LTbetaR) and the herpesvirus entry mediator (HVEM)/TR2. We investigated the effects of LIGHT on the human rhabdmyosarcoma cell line RD. LIGHT delayed cell proliferation and induced morphological changes of the cells. These effects were not shown by other TNF family ligands such as TNFalpha and LTalpha, which induced the transcriptional activity of nuclear factor-kappaB (NF-kappaB) and NF-kappaB-responsible chemokine productions in the same manner as did LIGHT. LTalpha1beta2, another TNF family ligand for LTbetaR, was shown to have similar activities in RD cells as LIGHT. Both LIGHT and LTalpha1beta2 induced the expression of muscle-specific genes such as smooth muscle (SM) alpha-actin, while TNFalpha and LTalpha did not. These findings indicate that LIGHT may be a novel inducer of RD cell differentiation associated with SM alpha-actin expression through the LTbetaR.
(c) 2001 Elsevier Science.