Clinical characteristics and prognosis of MLL-AF6 positive patients with acute myeloid leukemia / 北京大学学报(医学版)

OBJECTIVE@#To investigate the clinical features and prognosis of acute myeloid leukemia (AML) patients with the mixed lineage leukemia (MLL) gene rearrangements AF6 (MLL-AF6) positive.@*METHODS@#In the study, 11 patients who were newly diagnosed with MLL-AF6 positive AML were analyzed retrospectively, related literature was reviewed to clarify the clinical features and prognosis of MLL-AF6 positive patients.@*RESULTS@#Among the 11 patients, there were 6 males and 5 females, with a median age of 36 years. Six patients were diagnosed with AML M5 and five with M4 according to FAB classification (French-American-British classification systems). Gingival swelling and pain occurred in 6 cases and fever occurred in 5 cases. At first diagnosis, the median white blood cells were 55.5×109/L. Immunotype showed the expression of myeloid/monocyte and early stem cell series antigens. The expression level of MLL-AF6 fusion gene (real-time quantitative PCR) was 14.2%-214.5%, and 6/11 cases (54.5%) were associated with high EVI1 gene expression. Mutations of KRAS, TET2, ASXL1, TP53, DNMT3A, and FLT3-ITD were detected by next generation sequencing (NGS) in 4 patients. Chromosome G banding examination showed that 2 cases were t(6;11)(q27, q23) with complex karyotype abnormality, 4 cases with +8 abnormality and 2 cases with normal karyotype. Hematological complete remission (CR) was achieved in 8/11 patients (72.7%) after conventional induction chemotherapy, and primary drug resistance was observed in 3 patients. Two of the eight patients with CR were negative for minimal residual disease (MRD), with a median CR duration of 4.5 months. Two patients with positive MRD and three patients with refractory recurrence underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), but all died due to leukemia progression. At the end of follow-up on December 1, 2019, 2 patients were alive and 9 died, with median survival time of 9 months.@*CONCLUSION@#The AML patients with MLL-AF6 positive were mostly young, the majority of FAB types were M4 and M5, and most of the patients often had fever as the first symptom, with increased white blood cells, accompanied by organ infiltration, and high EVI1 gene expression. The hematological remission rate of routine chemotherapy is not low, but it is difficult to achieve molecular remission, most of which have early recurrence. Early allo-HSCT in a molecular negative state may prolong the CR duration.

Inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 and its mechanism / 中国实验血液学杂志

This study was aimed to investigate the inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 cells and its possible mechanism. The inhibition effect of brucine on growth of THP-1 cells was measured by CCK-8 method. Morphological changes of THP-1 cells treated with brucine was detected by acridine orange/ethidium bromide (AO/EB)double staining. Annexin-V/PI double labeling method was used to assay the apoptosis rate of THP-1 cells. The effect of brucine on THP-1 cell cycle distribution was detected by PI single staining. RT-PCR was used to detect the expression of BCL-2 and BAX. The results showed that the brucine could inhibit the THP-1 cell growth in concentration and time-dependent manners at the range of 50 to 400 µg/ml. The cells stained with AO/EB revealed that the brucine induced the nuclear chromatin condensation. After the THP-1 cells were treated with brucine of 400µg/ml for 48 hours, most nucleic were stained as orange-red, and condensed, displaying the late apoptotic cell morphology. Annexin-V/PI detection showed that brucine could induce apoptosis of THP-1 cells in a concentration-dependent manner. Compared with the control group, more cells in brucine-treated group were arrested at G0/G1 phase in a concentration-dependent manner. RT-PCR detection revealed that the expression of BCL-2 was down-regulated strikingly and BAX was up-regulated. It is concluded that brucine can efficiently inhibit cell growth and block THP-1 cells in G0/G1 phase. The mechanism of THP-1 cell apoptosis induced by brucine may be related to the inhibition of BCL-2 and activation of BAX.

Apoptosis-inducing effects of brucine on human chronic myeloid leukemia cell line K562 / 中国实验血液学杂志

To investigate the apoptosis-induction effect of brucine on human chronic myeloid leukemia cell line K562 cells, K562 cells were exposed to various dosages of brucine. MTT method was used to assayed the growth inhibition effect of brucine on K562 cells. The apoptosis of K562 cells was detected by acridine orange/ethidium bromide (AO/EB) double staining, Annexin-V/PI double labeling method and DNA agarose gel electrophoresis. The results showed that brucine could remarkably inhibit the K562 cell growth in a concentration-dependent and time-dependent manners at the range of 50 to 400 µg/ml, and its most significant inhibition was observed at 400 µg/ml for 72 hours and the inhibition rate was 94.0%. Staining of cells with AO-EB revealed that brucine induced nuclear chromatin condensation. After the K562 cells were treated with the brucine of 400 µg/ml for 72 hours, the most of the nucleus were orange stained and condensation-like or bead-like showing apoptotic morphology. The K562 cells treated with brucine of different concentrations (50, 100, 200, 400, 800 µg/ml) for 72 hours, Annexin-V/PI detection showed brucine could induce apoptosis of K562 cells, and apoptosis rate increased gradually with increasing concentration of drugs. The K562 cells treated with brucine of 400 µg/ml for 72 hours displayed typical ladder strap in DNA gel electrophoresis. It is concluded that brucine can efficiently inhibit cell growth and induce apoptosis of K562 cells with dose-dependent manner in concentrations of 50 - 400 µg/ml.