Expressions And Roles Of TRAIL Receptor DR5 And Ki67 On Primary Acute Leukemic Blasts

Backgrounds and ObjectiveTumor necrosis factor (TNF)-related apoptosis-inducing ligand(TRAIL) is a new member of the TNF superfamily , which induces apoptotic cell death in a variety of transformed cell lines, while sparing most normal cells. TRAIL-induced apoptosis is mediated through its death receptor DR5 or DR4.By binding to these receptors, TRAIL recruits an adaptor molecule FADD, and then activates caspase-8 to induce the apoptosis of cells. Five receptors for TRAIL have been identified: death receptor DR4, and DR5 transduce death signal and induce apoptosis; osteoprotegrin (OPG), TRAIL-R3/DcR1, TRAIL-R4/DcR2 can not activate death signal of apoptosis initiated by TRAIL. Cell surface expression of DR5 plays a significant role on TRAIL-induced apoptosis. The expression of DR5 varies in different tumor cells. DNA-damaging chemotherapeutic drugs upregulate the DR5 expression in some solid tumors. As a result, it increases the sensitivity of tumor cells to TRAIL-induced apoptosis and enhances the apoptosis of tumor cells induced by TRAIL. Ki67 is a proliferative antigen localized in the cellular nucleus and participates in cell mitosis. It is expressed throughout the cell cycle, such as G1, S, G2 and M phase except for the resting...