SENP3 Promotes Mantle Cell Lymphoma Development through Regulating Wnt10a Expression.

OBJECTIVE: SUMO-specific protease 3 (SENP3), a member of the SUMO-specific protease family, reverses the SUMOylation of SUMO-2/3 conjugates. Dysregulation of SENP3 has been proven to be involved in the development of various tumors. However, its role in mantle cell lymphoma (MCL), a highly aggressive lymphoma, remains unclear. This study was aimed to elucidate the effect of SENP3 in MCL. METHODS: The expression of SENP3 in MCL cells and tissue samples was detected by RT-qPCR, Western blotting or immunohistochemistry. MCL cells with stable SENP3 knockdown were constructed using short hairpin RNAs. Cell proliferation was assessed by CCK-8 assay, and cell apoptosis was determined by flow cytometry. mRNA sequencing (mRNA-seq) was used to investigate the underlying mechanism of SENP3 knockdown on MCL development. A xenograft nude mouse model was established to evaluate the effect of SENP3 on MCL growth in vivo. RESULTS: SENP3 was upregulated in MCL patient samples and cells. Knockdown of SENP3 in MCL cells inhibited cell proliferation and promoted cell apoptosis. Meanwhile, the canonical Wnt signaling pathway and the expression of Wnt10a were suppressed after SENP3 knockdown. Furthermore, the growth of MCL cells in vivo was significantly inhibited after SENP3 knockdown in a xenograft nude mouse model. CONCLUSION: SENP3 participants in the development of MCL and may serve as a therapeutic target for MCL.

Malic enzyme 2 connects the Krebs cycle intermediate fumarate to mitochondrial biogenesis.

Mitochondria have an independent genome (mtDNA) and protein synthesis machinery that coordinately activate for mitochondrial generation. Here, we report that the Krebs cycle intermediate fumarate links metabolism to mitobiogenesis through binding to malic enzyme 2 (ME2). Mechanistically, fumarate binds ME2 with two complementary consequences. First, promoting the formation of ME2 dimers, which activate deoxyuridine 5'-triphosphate nucleotidohydrolase (DUT). DUT fosters thymidine generation and an increase of mtDNA. Second, fumarate-induced ME2 dimers abrogate ME2 monomer binding to mitochondrial ribosome protein L45, freeing it for mitoribosome assembly and mtDNA-encoded protein production. Methylation of the ME2-fumarate binding site by protein arginine methyltransferase-1 inhibits fumarate signaling to constrain mitobiogenesis. Notably, acute myeloid leukemia is highly dependent on mitochondrial function and is sensitive to targeting of the fumarate-ME2 axis. Therefore, mitobiogenesis can be manipulated in normal and malignant cells through ME2, an unanticipated governor of mitochondrial biomass production that senses nutrient availability through fumarate.

Zinc finger and BTB domain-containing protein 46 is essential for survival and proliferation of acute myeloid leukemia cell line but dispensable for normal hematopoiesis.

BACKGROUND: Zinc finger and BTB domain-containing protein 46 (Zbtb46) is a transcription factor identified in classical dendritic cells, and maintains dendritic cell quiescence in a steady state. Zbtb46 has been reported to be a negative indicator of acute myeloid leukemia (AML). We found that Zbtb46 was expressed at a relatively higher level in hematopoietic stem and progenitor cells (HSPCs) compared to mature cells, and higher in AML cells compared to normal bone marrow (BM) cells. However, the role of Zbtb46 in HSPCs and AML cells remains unclear. Therefore, we sought to elucidate the effect of Zbtb46 in normal hematopoiesis and AML cells. METHODS: We generated Zbtb46 and Zbtb46Mx1-Cre mice. The deletion of Zbtb46 in Zbtb46Mx1-Cre mice was induced by intraperitoneal injection of double-stranded poly (I). poly (C) (poly(I:C)), and referred as Zbtb46 cKO. After confirming the deletion of Zbtb46, the frequency and numbers of HSPCs and mature blood cells were analyzed by flow cytometry. Serial intraperitoneal injection of 5-fluorouracil was administrated to determine the repopulation ability of HSCs from Zbtb46 and Zbtb46 cKO mice. The correlation between Zbtb46 expression and prognosis was analyzed using the data from the Cancer Genome Atlas. To investigate the role of Zbtb46 in AML cells, we knocked down the expression of Zbtb46 in THP-1 cells using lentiviral vectors expressing small hairpin RNAs targeting Zbtb46. Cell proliferation rate was determined by cell count assay. Cell apoptosis and bromodeoxyuridine incorporation were determined by flow cytometry. RESULTS: The percentages and absolute numbers of HSPCs and mature blood cells were comparable in Zbtb46 cKO mice and its Zbtb46 littermates (Zbtb46vs. Zbtb46 cKO, HPC: 801,310 ±â€Š84,282 vs. 907,202 ±â€Š97,403, t = 0.82, P = 0.46; LSK: 86,895 ±â€Š7802 vs. 102,210 ±â€Š5025, t = 1.65, P = 0.17; HSC: 19,753 ±â€Š3116 vs. 17,608 ±â€Š3508, t = 0.46, P = 0.67). The repopulation ability of HSCs from Zbtb46Mx1-Cre mice was similar to those from Zbtb46 control (P = 0.26). Zbtb46 had elevated expression in AML cells compared to total BM cells from normal control. Knockdown of Zbtb46 in THP-1 cells led to a significant increase in cell apoptosis and reduced cell growth and proliferation. CONCLUSION: Collectively, our data indicate that Zbtb46 is essential for survival and proliferation of AML cells, but dispensable for normal hematopoiesis.

Resveratrol: Review on its discovery, anti-leukemia effects and pharmacokinetics.

Resveratrol, found in variety of plants, is a natural stilbene structure polyphenol. It has various pharmacological effects, such as antioxidation, anti-aging, anti-inflammation, anti-cancer, antiobesity, anti-diabetes, cardioprotection, neuroprotection. Recently, anti-leukemia activities of resveratrol has been studied extensively via its effects on a variety of biological processes involving cell proliferation, apoptosis, autophagy. Current treatments of leukemia mainly rely on intensive chemotherapy or hematopoietic stem cell transplantation, however, these treatments are still with poor survival and high treatment-related mortality. Therefore, it is extremely needed to find relatively non-toxic medicines with minimal side effects but sufficient therapeutic efficacy. Resveratrol is one such potential candidate owing to its reported anti-leukemia effect. In this review, we summarized resveratrol's discovery, sources and isolation methods, administration methods, effects in different types of leukemia, pharmacokinetics and toxicities, aiming to exploit resveratrol as a potential drug candidate for anti-leukemia.

Technical Advances in Single-Cell RNA Sequencing and Applications in Normal and Malignant Hematopoiesis.

Single-cell RNA sequencing (scRNA-seq) has been tremendously developed in the past decade owing to overcoming challenges associated with isolation of massive quantities of single cells. Previously, cell heterogeneity and low quantities of available biological material posed significant difficulties to scRNA-seq. Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of normal and malignant hematopoietic cells; this heterogeneity has often been ignored in omics studies. The application of scRNA-seq has profoundly changed our comprehension of many biological phenomena, including organ development and carcinogenesis. Hematopoiesis, is actually a maturation process for more than ten distinct blood and immune cells, and is thought to be critically involved in hematological homeostasis and in sustaining the physiological functions. However, aberrant hematopoiesis directly leads to hematological malignancy, and a deeper understanding of malignant hematopoiesis will provide deeper insights into diagnosis and prognosis for patients with hematological malignancies. Here, we aim to review the recent technical progress and future prospects for scRNA-seq, as applied in physiological and malignant hematopoiesis, in efforts to further understand the hematopoietic hierarchy and to illuminate personalized therapy and precision medicine approaches used in the clinical treatment of hematological malignancies.

SIRT2 activates G6PD to enhance NADPH production and promote leukaemia cell proliferation.

Like most other types of cancer cells, leukaemia cells undergo metabolic reprogramming to support rapid proliferation through enhancing biosynthetic processes. Pentose phosphate pathway (PPP) plays a pivotal role in meeting the anabolic demands for cancer cells. However, the molecular mechanism by which PPP contributes to leukaemia remains elusive. Here, we report that leukaemia cell proliferation is dependent on the oxidative branch of PPP, in particular the first and rate-limiting enzyme glucose-6-phosphate dehydrogenase (G6PD). Knockdown of G6PD reduces NADPH level in acute myeloid leukaemia (AML) cell lines. Exogenous lipid supplements partially restore the proliferation of G6PD-depleted cells. Deacetylase SIRT2 promotes NADPH production through deacetylating G6PD at lysine 403 (K403). Activation of G6PD by SIRT2 supports the proliferation and clonogenic activity of leukaemia cells. Chemical inhibitors against SIRT2 suppress G6PD activity, leading to reduced cell proliferation of leukaemia cells, but not normal hematopoietic stem and progenitor cells. Importantly, SIRT2 is overexpressed in clinical AML samples, while K403 acetylation is downregulated and G6PD catalytic activity is increased comparing to that of normal control. Together, our study reveals that acetylation regulation of G6PD is involved in the metabolic reprogramming of AML, and SIRT2 serves as a promising target for further therapeutic investigations.

[PDGFRα Participates in Basic Fibroblast Growth Factor-mediated Recovery of Human Bone Marrow Mesenchymal Stem Cell Proliferation and Osteogenic Differentiation after Irradiation].

OBJECTIVE: To explore the effects of basic fibroblast growth factor (bFGF) on human bone marrow mesenchymal stem cell (hBMMSC) damaged by irradiation and its underlying mechanisms. METHODS: hBMMSC was irradiated with 0, 6, 12 Gy X ray, then flow cytometry, cell counting kit-8 (CCK-8), Western blot and alizarin red staining were used to detect the effects of X ray on apoptosis, proliferation and osteogenic differentiation of hBMMSC; 0, 1, 5, 10, 20 ng/ml bFGF was added to hBMMSC irradiated with X ray for selecting the suitable bFGF reaction concentration; then the Western blot was used to detect the expression of PDGFRα so as to evaluate whether the expression of PDGFRα participated in bFGF-mediated recovery of hBMMSC proliferation and osteogenic differentiation after irradiation. RESULTS: The proliferation and osteogenic differentiation of hBMMSC decreased remarkably after irradiation. bFGF promoted the recovery of proliferation and osteogenic differentiation of irradiated hBMMSC compared with untreated irradiated hBMMSC (P < 0.05); 5 ng/ml bFGF was identified as the optimal concentration. A significant difference in the number of apoptotic cells could be detected only between the 0 Gy group and 12 Gy group at the 24 h time point, while no differences were detected at later time points. Irradiated hBMMSC showed remarkable decrease of PDGFRα expression, while the PDGFRα expression increased after bFGF was added. CONCLUSION: Irradiation dose not show significant effect on apoptosis of hBMMSC, but the bFGF displays a effect on repairing the irradiation damage of hBMMSC and promotes the recovery of hBMMSC proliferation and osteogenic differentiation. The damage of hBMMSC proliferation and osteogenic differentiation associates with downregulation of PDGFRα expression induced by irrediation. PDGFRα involves in repairing effect of bFGF on irradiation damage of hBMMSC.

[Research advance on the pathogenesis of T-ALL induced by notch 1 activating mutations].

T-cell acute lymphoblastic leukemia (T-ALL) is the hematological malignancy of bone marrow characterized by the rapid proliferation and subsequent accumulation of immature T lymphocyte and mainly occurs in children and adolescents. In 1991, a kind of activating mutation of Notch 1 was found in a subset of T-ALL with chromosomal translocation t(7;9) for the first time. During the past 20 years since then, understanding of the relationship between Notch 1 activating mutation and T-ALL has been deepened and widened. This review briefly discusses the four main subtypes of Notch 1 activating mutations, also focuses on how these mutations change the normal signaling pathways and genes expression during their participation in the pathogenesis of T-ALL, and how these insights will promote the development of newly targeting therapies for patients with this aggressive form of leukemia.

[Arsenic trioxide in combination with all-trans retinoic acid for acute promyelocytic leukemia: a systematic review and meta-analysis].

BACKGROUND: The studies have demonstrated that arsenic trioxide (ATO) in combination with all-trans retinoic acid (ATRA) takes effects in treatment of acute promyelocytic leukemia (APL) through different underlying mechanisms. This has established the molecular foundation of ATO plus ATRA therapy. Currently, ATO plus ATRA has also been widely used in clinical practice. OBJECTIVE: To assess the efficacy and safety of ATO in combination with ATRA for APL. SEARCH STRATEGY: The Cochrane Library (Issue 1, 2009), Cochrane Central Register of Controlled Trials (from 1970 to January 2009), MEDLINE (from 1978 to October 2008), EMBASE (from 1950 to March 2009), Chinese Biological Medical Literature Database (from 1978 to December 2008), CNKI (from 1994 to December 2008), China Medical Academic Conference Database (from 1994 to December 2008) were electronically searched. We also searched the Meta-Register of Controlled Trials, Conference Proceedings of American Society of Hematology (from 1946 to December 2008) and Conference Proceedings of American Society of Clinical Oncology (from 1946 to December 2008) on the internet for grey literature. The authors also hand-searched Chinese periodicals potentially related to the question including Chinese Journal of Hematology, Journal of Experimental Hematology and Journal of Clinical Hematology. INCLUSION CRITERIA: All randomized controlled trials comparing ATO plus ATRA with other regimens for the treatment of APL were included. Intervention and comparison regimens include: 1) ATO plus ATRA vs ATO monotherapy; 2) ATO plus ATRA vs ATRA monotherapy; 3) ATO plus ATRA vs ATRA plus chemotherapy; 4) ATO plus ATRA vs ATO+ATRA+chemotherapy. DATA EXTRACTION AND ANALYSIS: Related data concerning complete remission rate, overall survival rate, and disease free survival rate, time to complete remission, relapse rate, mortality and adverse reactions were extracted independently by two reviewers. The different statistical methods were applied according to different data type with RevMan 5.0 software. RESULTS: After merging of the included trials, seven eligible randomized controlled trials with 392 cases were analyzed, among which 6 RCTs were methodologically graded as middle and one as of high risk of bias. The control therapies included ATO monotherapy, ATRA monotherapy and chemotherapy with ATO plus ATRA. Compared with ATO monotherapy, ATO plus ATRA could improve time to complete remission and relapse rate of newly diagnosed APL, but could not improve the complete remission rate, disease free survival rate, mortality and liver dysfunction of relapsed APL patients based on meta-analysis and sensitivity analysis. Compared with ATRA monotherapy, ATO plus ATRA shortened the time to complete remission, improved the disease free survival rate and relapse rate, but increased the incidence of edema during the treatment. Compared with chemotherapy with ATO plus ATRA, ATO plus ATRA could improve the complete remission rate, relapse rate, mortality and adverse reactions. CONCLUSION: For newly diagnosed APL, ATO plus ATRA is superior to ATO monotherapy, ATRA monotherapy and chemotherapy with ATO plus ATRA, but due to the lack of data about comparison with the current standard treatment regimen (ATRA plus chemotherapy), it is not enough to recommend ATO plus ATRA as a frontline therapy. For relapsed APL, ATO plus ATRA is not superior to ATO monotherapy, and ATRA plus ATO is not a supportive therapy. Due to limitation of sample size and risk of bias from the included trials, the effects of ATO plus ATRA need to be confirmed by large and high-quality randomized controlled trials.

[Efficacy of arsenic trioxide for acute promyelocytic leukemia: a systematic review and meta-analysis].

OBJECTIVE: To systematically review the efficacy and safety of arsenic trioxide (ATO) in treatment of acute promyelocytic leukemia (APL). METHODS: The Cochrane Library (Issue 1, 2009), Cochrane Central Register of Controlled Trials (from 1970 to January 2009), MEDLINE (from 1978 to October 2008), EMBASE (from 1950 to March 2009), Chinese Biological Medical Literature Database (from 1978 to December 2008), China National Knowledge Infrastructure (CNKI, from 1994 to December 2008), and China Medical Academic Conference Database (from 1994 to December 2008) were electronically searched. We also searched the Meta-Register of controlled trials, Conference Proceedings of American Society of Hematology (from 1946 to December 2008) and Conference Proceedings of American Society of Clinical Oncology (from 1946 to December 2008) on the internet for grey literature. The related journals in the library of Third Military Medical University were hand-searched. The randomized controlled trials (RCTs) of ATO in treatment of APL were included. We adopted complete remission, overall survival rate, disease free survival rate, time to complete remission, relapse rate, mortality and adverse reactions as outcome indicators. Data were entered and analyzed with the Cochrane review manager software 5.0 (RevMan 5.0). RESULTS: After merger of the included trials, five eligible RCTs with 328 cases were included. All the RCTs focused on the comparison of all-trans retinoic acid (ATRA) plus ATO regimen with ATRA monotherapy. Meta-analysis showed that the effect indexes for time to complete remission, two-year disease free survival rate, relapse rate, incidence of edema and incidence rate of QT interval prolongation were -1.20 [-1.68, -0.72], 8.64 [1.66,45.00], 0.21 [0.09,0.47], 4.16 [1.46,11.79] and 22.10 [2.75,177.49], respectively. The influences on other outcome indicators such as complete remission and leukocytosis were statistically non-significant. CONCLUSION: ATO can prolong disease free survival and reduce the time to complete remission and relapse rate of newly diagnosed APL patients, and increase the incidence of edema and prolongation of corrected QT interval during the treatment. Due to limitation of the included trials, this conclusion needs to be validated by further studies.