Suppression of Autophagy Can Augment PIK3 Inhibitor Induced Apoptosis in T Lymphoblastic Leukemia Cell Lines.

OBJECTIVE: The present study aimed to investigate the effects of the PI3K inhibitor PX-866 or PI-103 combined with the autophagy inhibitor 3-methyladenine (3-MA) on the apoptosis of T lymphoblastic leukemia cells. METHODS: The proliferation and apoptosis of T lymphoblastic leukemia cell lines were detected by CCK-8 and flow cytometer. The expression of proteins was measured by western blot. The effect of PI3K inhibitors combined with 3-MA on the number of autophagosomes was detected by transmission electron microscopy (TEM). RESULTS: We found PX-866 and PI-103 treatment reduced cell viability while increasing apoptosis in CCRF-CEM and Jurkat cells, which was further enhanced when combined with 3-MA. The phosphorylation levels of AKT and mTOR were suppressed by PX-866 or PI-103, which were reversed by 3-MA. Further, the expression of LC3, ATG5, ATG12 and Beclin-1 was upregulated by PX-866 or PI-103 and downregulated by 3-MA. TEM results revealed that the number of autophagosome was increased by PX-866 or PI-103 treatment, which was reversed by 3-MA. CONCLUSIONS: The results demonstrated that 3-MA could suppress PI3K inhibitor-mediated activation of autophagy to promote the apoptosis of tumor cells. This discovery provided experimental support for constituting a promising strategy for T-cell acute lymphoblastic leukemia (T-ALL) therapy.

[Treatment of two chronic myeloid leukemia patients with V299L mutation by using nilotinib].

This study was aimed to enhance clinical understanding the effect of nilotinib on CML patients with V299L mutation who were resistant to imatinib. Bone marrow specimens from 2 cases of CML with V299L mutation were collected before and after the treatment with nilotinib. ABL mutation was detected by nested reverse transcription polymerase chain reaction (PCR) followed by direct sequencing. The clinical characteristics of the two cases were analyzed. The results showed that both cases were resistant to imatinib presented V299L mutation. Out of them 1 case achieved complete haematological response (CHR) after treatment with nilotinib for 6 months and another case abstained obvious molecular response after using nilotinib for 7 month. V299L mutation of both cases was turned into negative after the treatment with nilotinib. It is concluded that the nilotinib can safely and effectively override tyrosine kinase inhibitor (TKI) resistance mediated by the V299L mutation. The safety and efficacy of nilotinib for treatment of CML patients with TKI resistance and V299L mutation are satisfactory.

[SRSF2 mutation in patients with chronic myelomonocytic leukemia].

OBJECTIVE: To investigate SRSF2 mutations in patients with chronic myelomonocytic leukemia (CMML) and the clinical characteristics of patients with SRSF2 mutants. METHODS: In this study, the frequency of SRSF2 mutation in a cohort of 20 patients with CMML was detected by polymerase chain reaction (PCR) followed by direct sequencing to couple with their clinical features. RESULTS: Of 20 patients, 4 patients were found harboring SRSF2 mutations, including 2 P95L, 1 P95H and 1 P95R point mutations. There were no significantly statistical differences in terms of their clinical characteristics between mutant and wild type group. CONCLUSION: SRSF2 mutation was not frequently occurred in CMML patients and might associated with poor prognosis. It might be a practically diagnostic maker and therapeutic target in CMML.

[Anti-human 4-1BBL monoclonal antibody stimulates the nuclear translocation of NF-κB and the co-location of 4-1BBL/CD28 isoform in U937 cells].

This study was purposed to investigate the molecular mechanism of 4-1BBL reverse signals in the human acute monocytic leukemia cell line of U937. The U937 cell line was used as target cells, and stimulated by the mouse anti-human 4-1BBL monoclonal antibody 1F1. The nuclear translocation of NF-κB and the co-location of 4-1BBL and CD28i molecules in U937 cells were observed with confocal laser scanning microscopy. The protein and m-RNA expression levels of 4-1BBL and CD28i were detected by flow cytometry and RT-PCR respectively. The results showed that the significant nuclear translocation of NF-κB and co-localization of 4-1BBL and CD28i on membrane of U937 cells appeared after being stimulated by mAb1F1. It is concluded that the 4-1BBL reverse signals transduction mediating the growth of U937 cells relates with the nuclear translocation of NF-κB. CD28i may be involved in intracellular 4-1BBL reverse signaling pathways.

[Detection of serum neopterin in patients with hemophagocytic lymphohistiocytosis and its significance].

This study was aimed to detect the peripheral blood serum neopterin (Npt) level in the patients with hemophagocytic lymphohistiocytosis (HLH) and to explore its significance in HLH. The enzyme-linked immunosorbent assay (ELISA) was applied to detect the serum Npt level and sCD25 level in 20 HLH patients before and after treatment and 15 healthy controls. The results indicated that the serum Npt and sCD25 levels in HLH patients were significantly higher than those in healthy controls (P < 0.0001). The serum Npt and sCD25 levels in the HLH group decreased significantly after treatment, respectively (P < 0.0001). The correlation analysis of Npt with sCD25 before and after treatment showed that they had significant correlation (r = 0.81, P < 0.05 before treatment; r = 0.65, P < 0.05 after treatment). Meanwhile, the level of serum Npt and ferritin had a significant correlation in newly diagnosed HLH patients (r = 0.55, P < 0.05). It is concluded that the serum Npt may play an important role in the HLH pathogenesis, the enhancement of Npt levels has an important significance for diagnosis and evaluation for HLH.