OBJECTIVETo study the effects of RNA interference inhibiting stromal cell derived factor-1 (SDF-1) expression on the proliferation and apoptosis of co-cultured Jurkat cells.

METHODInhibition of SDF-1 expression by RNA interference (RNAi) was achieved by transferring SDF-1 specific short hairpin RNA (shRNA) expressing plasmid into cultured human acute leukemic bone marrow stromal cells. Resistant clones were obtained by G418 selection (group A). The concentration of SDF-1 protein in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The population double time (PDT), cell cycles, apoptosis rates and the expressions of PCNA, Bcl-2/Bax, Fas/FasL of co-cultured Jurkat cells were detected by cells counting, flow cytometry. TdT-mediated dUTP nick-end labelling (TUNEL) and immunocytochemistry (ICC), respectively. The un-transfected acute leukemic (group B) and normal (group C) bone marrow stromal cells were taken as controls.

RESULTSThe content of SDF-1 protein in supernatant of group A\[(384 +/- 41) pg/ml] was significantly lower than that in group B[(2474 +/- 271) pg/ml] or group C[(1324 +/- 154) pg/ml]. As group A compared with group B and group C, the PDT of co-cultured Jurkat cells was prolonged (group A: 42 h, vs group B: 29 h, group C: 33 h), and G(0)/G(1) stage cells increased [group A: (28.47 +/- 2.39)%, vs group B: (19.43 +/- 2.80)%, group C: (27.15 +/- 2.07)%], S stage cells decreased [group A: (25.57 +/- 1.90)%, vs group B: (74.48 +/- 3.23)%, group C: (60.99 +/- 2.33)%], G(2)/M stage cells increased [group A: (45.96 +/- 3.24)%, vs group B: (6.09 +/- 1.96)%, group C: (11.86 +/- 1.98)%], the apoptosis rate increased [group A: (15.2 +/- 0.8)%, vs group B: (5.4 +/- 0.7)%, group C: (9.5 +/- 0.4)%], and the expressions of PCNA, Bcl-2, Fas decreased; whereas the expressions of Bax and FasL were increased.

CONCLUSIONThe inhibition of SDF-1 expression in bone marrow stromal cells inhibits the proliferation and promotes the apoptosis of co-cultured Jurkat cells.