OBJECTIVETo investigate the effect of phosphorylated protein kinase C epsilon (pPKC epsilon) on apoptosis of 32D cells induced by sera from patients with aplastic anemia (AA).

METHODSThe expression of pPKC epsilon and apoptosis in 32D cells were measured by Western blotting and flow cytometry after incubation with sera from healthy individuals (controls, n = 8), patients with severe AA ( SAA, n = 8)and non severe AA (NSAA, n = 6).

RESULTSAfter incubation for 0, 12, 24, 36 and 48 hours in the presence of serum and for another 4 hours in medium deprived of serum, the levels of pPKC epsilon in cells in SAA and NSAA group increased gradually, peaked at 24 hours, and then declined (P < 0.05). Compared with that in control group (0.54 +/- 0.08), pPKC epsilon was overexpressed in both SAA group (0.90 +/- 0.10) and NSAA group (0.64 +/- 0.08) (P < 0.05) after 24 hours incubation with serum and subsequent 4 hours without serum. pPKC epsilon level was higher in SAA group than in NSAA group (P < 0.05). A greater proportion of 32D cells showed apoptosis after 24 hours incubation with sera from SAA patients [(4.05 +/- 1.05)%] and subsequent 4 hours incubation without serum than that in controls [(2.45 +/- 0.51)%, P < 0.05], which was correlated with the same serum-induced expression of pPKC epsilon (r = 0.869, P < 0.05). Although the mean level of pPKC epsilon expression was higher in NSAA group than in control group, no significant difference of apoptosis was found between the two groups [(2.45 +/- 0.51)% vs (3.24 +/- 0.56)%, P > 0.05].

CONCLUSIONSera from both SAA and NSAA patients could upregulate the expression of pPKC epsilon in 32D cells. The SAA sera induce apoptosis in 32D cells significantly, but the latter do not.