RXRalpha mRNA expression is associated with cell proliferation and cell cycle regulation in Hep3B cell.

Retinoids are well-characterized differentiation and anti-proliferation agents. The functional role of retinoid x receptor alpha (RXRalpha) in cell proliferation and cell cycle regulation is not well understood. Using human Hep3B cell line, we showed that the mRNA level of RXRalpha was closely associated with cell growth. RXRalpha mRNA expression elevated along with the proliferation of Hep3B cells. This association was most evident in RXRalpha and was also noted with retinoic acid (RA) receptor alpha (RARalpha), but not found in other RARs and RXRs. The expression of RXRalpha and cyclin A mRNA was co-regulated when Hep3B cells were cultured in serum-free medium. The mRNA levels of RXRalpha and cyclin A appeared to be highest in G1/S phase in Hep3B cells treated by aphidicolin. Taken together, our data suggest that RXRalpha may be actively involved in cell proliferation and cell cycle regulation in Hep3B cells.