Inhibiting effect of CaMKIIN up-regulation on leukemia cells growth and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the inhibitory effects of CaMKIIN on acute myeloid leukemia cell line HL-60 to explore a novel therapeutic target of leukemia.</p><p><b>METHODS</b>Human CaMK II N gene expression vector pcDNA3.1/hCaMKIIN or empty vector pcDNA3.1/myc-His (-) B was transfected into HL-60 cells by Lipofectamine 2000. Human CaMK II N proteins of transfected cells were detected by Western blot. Cell proliferation affected by human CaMKIIN was determined by MTT. Colony-forming assay was performed by soft agar growth system. The cells transfected with CaMKIIN were stained with Hoechst 33342 to detect the apoptotic proportion under fluorescence microscopy. Cell cycle was analyzed by flow cytometry.</p><p><b>RESULTS</b>Human CaMKIIN was stably transfected into HL-60 cells, and overexpression of human CaMKIIN inhibited the proliferation of HL-60/CaMKIIN cells compared to HL-60/mock cells and HL-60 cells [(0.44 ± 0.03) vs (0.94 ± 0.05) vs (0.94 ± 0.04), P<0.01]. The colony formation of HL-60/CaMKIIN was also markedly smaller[(21.00 ± 3.05)/500] than that of mock-transfected [(111.00±4.58)/500]] and control cells [(119.00±6.09)/500] (P<0.01). After 72 hrs-culture, the apoptotic proportion in cells transfected with CaMK II N was obviously higher than of cells transfected with mock DNA or control [(22.49 ± 2.15)% vs (7.17 ± 0.72)% vs (6.40 ± 0.55)%, P<0.01]. Up to (82.97 ± 2.90)% human CaMKIIN/HL-60 cells were arrested at G0/G1 phase, which was more than mock-transfected [(40.53 ± 2.38)%] and control cells [(41.63 ± 2.27)%] (P<0.05). Human CaMKIIN could down-regulate expression of Bcl-2 in transfected cells.</p><p><b>CONCLUSION</b>CaMK IIN up-regulation could inhibit proliferation and induce apoptosis of human acute myeloid leukemia cell HL-60.</p>

Expression of transcription factor LYL1 in leukemia and its possible role in leukemogenesis / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the expression of transcription factor LYL1 in leukemia and its possible role in leukemogenesis.</p><p><b>METHODS</b>Fluorescence real time quantitative polymerase chain reaction was used to detect the expression levels of LYL1 in leukemias. Specific siRNA was used to silence the expression of LYL1 in K562 cells.</p><p><b>RESULTS</b>Compared to CD34 positive cells from normal bone marrow, the expression of LYL1 was significantly elevated in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). LYL1 expression was higher in chronic myeloid leukemia (CML) in blastic crisis than that in chronic phase (7.831 vs 1.672, P < 0.01). LYL1 expression in AML in complete remission (CR) was down-regulated as compared with that of un-remission patients (1.400 vs 9.985, P < 0.01). Down-regulation of endogenous expression of LYL1 in K562 cells by a combination of three specific siRNA could inhibit cellular growth and clonogenicity to some extent.</p><p><b>CONCLUSION</b>Over-expression of LYL1 is highly associated with AML as well as ALL. RNA interference targeting specific oncogenes such as LYL1 is potentially useful in the treatment of hematological malignancies.</p>