High prevalence of hepatitis B virus infection in patients with aggressive B cell non-Hodgkin's lymphoma in China.

We retrospectively analyzed a large study to investigate the association of hepatitis B virus (HBV) with aggressive B cell non-Hodgkin's lymphoma (aggressive B-NHL) in China, where HBV is endemic. HBV was present in 39 aggressive B-NHL patients (10.46%), 13 indolent B-NHL patients (5.09%), 12 multiple myeloma (MM) patients (3.67%), and 5 solitary plasmacytoma (SP) patients (6.67%). HBV infection was significantly associated with increased risks for aggressive B-NHL (P < 0.01). HBV seems to have a very important role in the pathogenesis of aggressive B-NHL in China.

[Clinical Analysis on the Therapeutic Efficacy of Autologous Hematopoietic Stem Cell Transplantation in 56 Multiple Myeloma Patients].

OBJECTIVE: To evaluate the therapeutic efficacy and prognosis of autologous stem Hematopoietic cell transplantation (auto-HSCT) in multiple myeloma (MM) patients. METHODS: A retrospective study was conducted for 56 patients diagnosed with MM and then received auto-HSCT in our hospital from December 2008 to September 2016. RESULTS: All the patients successfully underwent hematopoietic reconstruction without transplantation-related mortality (TRM). The complete response (CR) rate of all the patients after induction chemotherapy was 23.2% (13/56), while the CR rate of these patients with auto-HSCT increased to 78.6% (44/56) (P<0.01). The CR plus VGPR (very good partial response) rates of these 56 patients after induction chemotherapy and auto-HSCT were 53.6%（30/56）and 94.6%（53/56） respectively (P<0.01). The median progression-free survival (PFS) time and median overall survival (OS) time were 37 and 71 months, respectively. The median PFS time in the patients with induction therapy containing bortezomib was 37 months, however, the median OS time did not reach to 71 months; the median PFS (P<0.01) and the median OS (P<0.01) in the patients with the induction chemotherapy without bortezomib was 27 and 51 months, respectively. Univariate analysis demonstrated that the patients maintained CR or VGPR after auto-HSCT or with less than 6 cycles of induction chemotherapy significantly correlated with PFS (P<0.01). CONCLUSION: auto-HSCT can further increase the CR rate, prolong PFS and OS time. Sequential auto-HSCT after bortezomib-based therapy is the first line therapy for the transplant-eligible MM patients. Maintenance treatment is beneficial to the sustained CR+VGPR patients after auto-HSCT.

A novel epigenetic AML1-ETO/THAP10/miR-383 mini-circuitry contributes to t(8;21) leukaemogenesis.

DNA methylation patterns are frequently deregulated in t(8;21) acute myeloid leukaemia (AML), but little is known of the mechanisms by which specific gene sets become aberrantly methylated. Here, we found that the promoter DNA methylation signature of t(8;21)+ AML blasts differs from that of t(8;21)- AMLs. This study demonstrated that a novel hypermethylated zinc finger-containing protein, THAP10, is a target gene and can be epigenetically suppressed by AML1-ETO at the transcriptional level in t(8;21) AML. Our findings also show that THAP10 is a bona fide target of miR-383 that can be epigenetically activated by the AML1-ETO recruiting co-activator p300. In this study, we demonstrated that epigenetic suppression of THAP10 is the mechanistic link between AML1-ETO fusion proteins and tyrosine kinase cascades. In addition, we showed that THAP10 is a nuclear protein that inhibits myeloid proliferation and promotes differentiation both in vitro and in vivo Altogether, our results revealed an unexpected and important epigenetic mini-circuit of AML1-ETO/THAP10/miR-383 in t(8;21) AML, in which epigenetic suppression of THAP10 predicts a poor clinical outcome and represents a novel therapeutic target.

SIRT2 is an unfavorable prognostic biomarker in patients with acute myeloid leukemia.

SIRT2 is a member of the NAD+ dependent deacetylases. In this study, the associations between SIRT2 expression and molecular and clinical characteristics of patients with acute myeloid leukemia (AML) were evaluated by data from The Cancer Genome Atlas. SIRT2 was overexpressed in the intermediate- and poor-risk groups of patients, compared to the favorable-risk group of patients (P = 0.002 and 0.004, respectively). High SIRT2 expression was associated with significantly shorter overall survival (OS; P = 0.0005) and event-free survival (EFS; P = 0.0002) than low SIRT2 expressio in a cohort of 167 patients with AML. Multivariate analyses revealed that high SIRT2 expression was associated with shorter OS (P = 0.031) and EFS (P = 0.020). Gene-expression profiling showed 259 differential expressed genes including CD4, CD14 and IL10. Gene sets like MAPK signaling pathway, VEGF signaling pathway and acute myeloid leukemia were upregulated in SIRT2(high) patients. We also found different methylation patterns in these two groups. OS and EFS of SIRT2(high) patients who did not undergo transplantation were significantly shorter than those of SIRT2(low) patients (P = 0.0120 and P = 0.0107, respectively). Taken together, these findings suggest that high SIRT2 expression is a novel and unfavorable prognostic biomarker for AML risk-stratification.

Increased PRAME-specific CTL killing of acute myeloid leukemia cells by either a novel histone deacetylase inhibitor chidamide alone or combined treatment with decitabine.

As one of the best known cancer testis antigens, PRAME is overexpressed exclusively in germ line tissues such as the testis as well as in a variety of solid and hematological malignant cells including acute myeloid leukemia. Therefore, PRAME has been recognized as a promising target for both active and adoptive anti-leukemia immunotherapy. However, in most patients with PRAME-expressing acute myeloid leukemia, PRAME antigen-specific CD8(+) CTL response are either undetectable or too weak to exert immune surveillance presumably due to the inadequate PRAME antigen expression and PRAME-specific antigen presentation by leukemia cells. In this study, we observed remarkably increased PRAME mRNA expression in human acute myeloid leukemia cell lines and primary acute myeloid leukemia cells after treatment with a novel subtype-selective histone deacetylase inhibitor chidamide in vitro. PRAME expression was further enhanced in acute myeloid leukemia cell lines after combined treatment with chidamide and DNA demethylating agent decitabine. Pre-treatment of an HLA-A0201(+) acute myeloid leukemia cell line THP-1 with chidamide and/or decitabine increased sensitivity to purified CTLs that recognize PRAME(100-108) or PRAME(300-309) peptide presented by HLA-A0201. Chidamide-induced epigenetic upregulation of CD86 also contributed to increased cytotoxicity of PRAME antigen-specific CTLs. Our data thus provide a new line of evidence that epigenetic upregulation of cancer testis antigens by a subtype-selective HDAC inhibitor or in combination with hypomethylating agent increases CTL cytotoxicity and may represent a new opportunity in future design of treatment strategy targeting specifically PRAME-expressing acute myeloid leukemia.

A histone acetyltransferase p300 inhibitor C646 induces cell cycle arrest and apoptosis selectively in AML1-ETO-positive AML cells.

AML1-ETO fusion protein (AE) is generated by t(8;21)(q22;q22) chromosomal translocation, which is one of the most frequently observed structural abnormalities in acute myeloid leukemia (AML) and displays a pivotal role in leukemogenesis. The histone acetyltransferase p300 promotes self-renewal of leukemia cells by acetylating AE and facilitating its downstream gene expression as a transcriptional coactivator, suggesting that p300 may be a potential therapeutic target for AE-positive AML. However, the effects of p300 inhibitors on leukemia cells and the underlying mechanisms have not been extensively investigated. In the current study, we analyzed the anti-leukemia effects of C646, a selective and competitive p300 inhibitor, on AML cells. Results showed that C646 inhibited cellular proliferation, reduced colony formation, evoked partial cell cycle arrest in G1 phase, and induced apoptosis in AE-positive AML cell lines and primary blasts isolated from leukemic mice and AML patients. Nevertheless, no significant inhibitory effects were observed in granulocyte colony-stimulating factor-mobilized normal peripheral blood stem cells. Notably, AE-positive AML cells were more sensitive to lower C646 doses than AE-negative ones. And C646-induced growth inhibition on AE-positive AML cells was associated with reduced global histone H3 acetylation and declined c-kit and bcl-2 levels. Therefore, C646 may be a potential candidate for treating AE-positive AML.