Objective        To determine the apoptosis-inducing effect of protocadherin 10 gene (PCDH10) on multiple myeloma (MM) cells and its mechanisms.       Methods        The human MM cell line KM3 was stably transfected with pcDNA3.1(+)PCDH10 or pcDNA3.1(+) by lipofectamine. Untransfected and pcDNA3.1(+) plasmid transfected cells were used as control. The expression of PCDH10 at mRNA and protein levels in the PCDH10-transfected cells were detected by real-time PCR and Western blotting. Cell proliferation after transfection was detected by MTT assay. The apoptotic

rate was assayed by flow cytometry

and transmission electron microscopy (TEM) was employed to observe the ultra-structure of the cells. The expressions of apoptosis-related proteins were detected by Western blotting.       Results        Transfection of PCDH10 resulted in obviously increased expression of PCDH10 at mRNA and protein levels. MTT assay showed that the proliferation of PCDH10-KM3 cells was significantly suppressed (

P

0.05). Flow cytometry revealed increased apoptosis in KM3 cells transfected with PCDH10 (

P

0.05). TEM displayed that the PCDH10-transfected KM3 cells had cytoplasmic cavities

karyopyknosis and obvious apoptotic bodies. But no such change was found in the control cells. At the same time PCDH10-transfected KM3 cells resulted in down-regulation of Bcl-2 (

P

0.05)

and up-regulation of p53 and Fas gene (

P

0.05).       Conclusion       PCDH10 plays a promoting role in the apoptosis of MM cell line KM3.