Biphasic modulation of cell growth by recombinant human galectin-1

摘要

Human solulilt galiiclosobinding Icclin (galcxlin-l) h;is been expressed us an Escherichia call fusion protein, following, the amplification by pulynierase chain reaction of cDNA prepared from a luinian osk'osarcoma cell line. The fusion protein is a functional galiictcsiciti-Witicling lectin, us is the rrambiiuiiit galectiii when purified from liie cleaved fusion protein. The recombinant galectin has a diphasic effoot on cell proliferation. Unlike (he fusion prolein, it functions as a human cell growth inhibitor, confirming earlier findings with natural human galectin-1, though it is less effective than ihe natural galectin. This reaction is not significantly inhibited by lactose, and is thus Isirjdy independent of the jy-galacniside-biiiding site. At lower concentrations, recombinant galectin-1 is mitogenic, this activity being susceptible to inhibition by Inclose, and thus attributable to the /3-galactoside-binding ability of the protein. Some tumour cells are su.soeplible to the growth-inhibitory effect, ami the galeclin-l gene is expressed in both normal and tumour cells.