Expression of TRAIL Receptors on the Multiple Myeloma Cells.

Objective To study the different expression of death receptors and decoy receptors on mononuclear cells from patients with multiple myeloma and myeloma cell line KM3 and compare the different expression of TRAIL receptors after chemotherapy or exposure to doxorubicin, to explore the mechanisms by which TRAIL selectively kills tumor cells.

Methods Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry was used to investigate the expression of four receptors on mononuclear cells in 23 multiple myeloma patients and myeloma cell line KM3 and 15 controls, we furthermore compared the changes of expression mode after chemotherapy and incubation of KM3 cell with sub-clinical concentration of Doxorubicin.

Results There finds only DR4 and DR5 on KM3 cell line without the expression of DcR1 and DcR2. Expression of DR4 and DR5 on mononuclear cells of MM patients is higher than that of controls (P<0.05), but DcR1 and DcR2 expression was lower than that of controls (P<0.05), after chemotherapy and exposure to Doxorubicin, the expression of DR5 on MM cells was up-regulated (P<0.05)

Conclusions The expression of four receptors on myeloma cells and normal controls was significantly different, which might account for the selective killing effect of TRAIL on MM cells. DR5 was up-regulated on KM3 when incubating with Doxorubicin and after chemotherapy which suggests chemotherapy agents might enhance the apopotosis of MM cells through up-regulating of DR5 receptor.