@@

Aim To observe the effect of the LSD1 gene on the proliferation and apoptosis of Molt-4 cells, a kind of human acute T-lymphoblastic leukemia cells. Methods siRNA fragment based on LSD1 gene was designed, filtered out and then transfected into Molt-4 cells. The effects of LSD 1 siRNA on Molt-4 cell prolif-eration were observed by the method of MTS. The cell apoptosis was analyzed by flow cytometry. The states of histone H3K4, H3K9 methylation, histone H3 acetyla-tion, p15, DNA methyltransferase 1 (DNMT1), and apoptosis-related proteins like Bcl-2 , procaspase-3 were evaluated by Western blot. Results Silencing LSD1 gene inhibited cell proliferation. Molt-4 cell pro-liferation rate was ( 99. 65 ± 1. 21 )%, ( 83. 02 ± 1. 69)%, (65. 72 ± 2. 16)%,and (41. 15 ± 2. 23)%respectively after the treatment of Molt-4 cells with 0 , 30, 60, 120 nmol·L-1 of LSD1 siRNA after 48 hours ( P < 0. 05 ) . Cell proliferation rate was ( 99. 86 ± 1. 35)%,(65. 72 ± 2. 16)%,(48. 26 ± 1. 92)%,and ( 37. 86 ± 1. 66 )% respectively after the transfection of Molt-4 cells with 60 nmol · L-1 of LSD1 siRNA after 0 , 24 , 48 , 72 hours ( P<0. 05 ) . Cell apoptosis rate was ( 3. 35 ± 1. 26 )%, ( 12. 16 ± 1. 74 )%, ( 32. 74 ± 2. 47 )%, ( 54. 64 ± 2. 58 )% respectively after transfection of LSD1 siRNA in indicated concentrations for 48 hours ( P <0. 05 ) . At the same time, the ex-pression levels of apoptosis-related proteins like Bcl-2 , procaspase-3 decreased. LSD1 siRNA inhibited LSD1 and LSD1 mRNA, and accumulated histone mono-, and di-methylation H3K4 and histone H3 acetylation. However, alteration of H3K4 trimethylation, H3K9 methylation was not detected. LSD1 siRNA downregu-lated DNA demethylase DNMT1 and upregulated p15 . Conclusions LSD1 siRNA can inhibit Molt-4 cell proliferation and induce apoptosis. Its mechanism may be associated with epigenetic regulation. In addition, it is expected to become a new target for leukemia treat-ment.

Objective:To explore the cooperation and clinical significance of HIF-1α,ALDH1 and Hedgehog signaling pathway in the activation of cancer stem cell(CSC) in triple negative breast cancer(TNBC).Methods: ALDH1+(Aldehyde dehydrogenase1)breast cancer stem cells and ALDH1-breast cancer cells were selected from MDA-MB-231 cells by magnetic activated cell sorting system(MACS),qRT-PCR method was employed to analyze the expression differences of HIF-1α and Hedgehog signaling molecules Sonic hedgehog(SHH),patched1(PTCH1),Smoothened(SMO) and Glioma-associated oncogene homoglog1(GLI1) in ALDH1+ breast cancer stem cells and ALDH1-breast cancer cells.Immunohistochemical method was applied to study the expressions of HIF-1α and ALDH1 and the relationships among HIF-1α,ALDH1 and Hedgehog signaling molecules in TNBC.Results: The expressions of HIF-1α mRNA,SMO mRNA and GLI1 mRNA in ALDH1+ breast cancer stem cell were higher than those in ALDH1-breast cancer cell(P all<0.05).The positive expression rates of HIF-1α were 90.0% and 70.0%,and the positive rates of ALDH1 were 93.3 % and 66.7 % in TNBC and non-TNBC,respectively(P all<0.05).Spearman rank correlation analysis showed that the expression of HIF-1α was positively related with that of ALDH1 in TNBC(r=0.53,P<0.01).HIF-1α expression was correlated with lymph node metastasis and TNM stage(P all<0.05),ALDH1 expression was correlated with histological grade and TNM stage(P all<0.05).In addition,the expression of HIF-1α was positively related with that of Hedgehog signaling molecules SHH(r=0.584,P<0.01),SMO(r=0.467,P<0.01) and GLI1(r=0.439,P<0.05),the expression of ALDH1 was positively related with that of SHH(r=0.426,P<0.05) and GLI1(r=0.394,P<0.05).Conclusion: HIF-1α and Hedgehog signaling pathway were activated in ALDH1+ breast cancer stem cell.HIF-1α,ALDH1 and Hedgehog molecules may cooperate with each other to activate breast CSC to promote the malignant progression of TNBC.