OBJECTIVE: To explore the effect and mechanism of DNA methyltransferase 1 (DNMT1) knockout on the inhibition of acute myeloid leukemia (AML) by natural killer (NK) cells. METHODS: The peripheral blood NK cells of AML patients and controls were collected, and the mRNA and protein level of DNMT1 were measured by PCR and Western blot, respectively. The DNMT1 knockout mice were constructed to obtain NK^DNMT1-/- cells. The NK cells were stimulated with interleukin (IL)-12, IL-15, and IL-18 to construct memory NK cells, and then the interferon-γ (IFN-γ) levels were measured by ELISA. After co-culturing with memory NK cells and HL60 cells, the killing effect of NK^DNMT1-/- cells on HL60 cells was detected by LDH assay. Then, the HL60 cell apoptosis and NK cell NKG2D level were measured by flow cytometry. The perforin and granzyme B protein levels of NK cells were measured by Western blot. The AML model mice were constructed by injecting HL60 cells into the tail vein, meanwhile, memory NK cells were also injected, and then the mouse weights, CD33 positive rates, and survival time were detected. RESULTS: The mRNA and protein levels of DNMT1 in NK cells of AML patients were significantly higher than those in the control group (both P < 0.01), while the IFN-γ level induced by interleukin was significantly lower than that in the control group (P < 0.05). Compared with NK^DNMT1+/+ cells, the ability of NK^DNMT1-/- cells to secrete IFN-γ after interleukin stimulation was significantly increased (P < 0.05). The killing and apoptosis-inducing effects of NK^DNMT1-/- cells on HL60 cells were significantly stronger than those of NK^DNMT1+/+ cells (both P < 0.05). The NKG2D level and expression of perforin and granzyme B of NK^DNMT1-/- cells were significantly increased compared with NK^DNMT1+/+ cells (all P < 0.05). Compared with AML mice injected with NK^DNMT1+/+ cells, AML mice injected with NK^DNMT1-/- cells showed significantly increased body weight, decreased CD33 positive rate, and prolonged survival time (all P < 0.05). CONCLUSION Knocking out DNMT1 can enhance the inhibitory effect of NK cells on AML, which may be related to enhancing NK cell memory function.
Killer Cells, Natural/metabolism* ; Animals ; Leukemia, Myeloid, Acute ; Humans ; DNA (Cytosine-5-)-Methyltransferase 1 ; Mice ; Mice, Knockout ; HL-60 Cells ; Apoptosis ; Interferon-gamma/metabolism* ; Granzymes/metabolism* ; Perforin/metabolism* ; NK Cell Lectin-Like Receptor Subfamily K/metabolism*

The cooccurrence of NPM1, FLT3-ITD, and DNMT3A mutations (i.e., triple mutation) is related to dismal prognosis in patients with acute myeloid leukemia (AML) receiving chemotherapy alone. In this multicenter retrospective cohort study, we aimed to identify whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) could overcome the poor prognosis of DNMT3A^mutNPM1^mutFLT3-ITD^mut AML across four transplant centers in China. Fifty-three patients with triple-mutated AML receiving allo-HSCT in complete remission were enrolled. The 1.5-year probabilities of relapse, leukemia-free survival, and overall survival after allo-HSCT were 11.9%, 80.3%, and 81.8%, respectively. Multivariate analysis revealed that more than one course of induction chemotherapy and allo-HSCT beyond CR1 were associated with poor survival. To our knowledge, this work is the largest study to explore the up-to-date undefined role of allo-HSCT in patients with triple-mutated AML. Our real-world data suggest that allo-HSCT could overcome the poor prognosis of DNMT3A^mutNPM1^mutFLT3-ITD^mut in AML.
Humans ; Nucleophosmin ; Leukemia, Myeloid, Acute/mortality* ; Hematopoietic Stem Cell Transplantation/methods* ; Male ; Female ; DNA Methyltransferase 3A ; Adult ; China ; Retrospective Studies ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; Middle Aged ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics* ; Mutation ; Young Adult ; Transplantation, Homologous ; Nuclear Proteins/genetics* ; Adolescent ; Aged

OBJECTIVE: To observe the clinical significance of translocator proteins (TSPO) gene in the treatment of FLT3-ITD/DNMT3A R882 double-mutated acute myeloid leukemia (AML). METHODS: Seventy-six patients with AML hospitalized in the Department of Hematology of the Affiliated People's Hospital of Ningbo University from June 2018 to June 2020 were selected, including 34 patients with FLT3-ITD mutation, 27 patients with DNMT3A R882 mutation, 15 patients with FLT3-ITD/DNMT3A R882 double mutation, as well as 19 patients with immune thrombocytopenia (ITP) hospitalized during the same period as control group. RNA was routinely extracted from 3 ml bone marrow retained during bone puncture, and TSPO gene expression was detected by transcriptome sequencing (using 2-deltadeltaCt calculation). RESULTS: The expression of TSPO gene in FLT3-ITD group and DNMT3A R882 group at first diagnosis was 2.02±1.04 and 1.85±0.76, respectively, which were both higher than 1.00±0.06 in control group, but the differences were not statistically significant (P=0.671, P=0.821). The expression of TSPO gene in the FLT3-ITD/DNMT3A R882 group was 3.98±1.07, wich was significantly higher than that in the FLT3-ITD group and DNMT3A R882 group, the differences were statistically significant (P=0.032, P=0.021). The expression of TSPO gene in patients who achieved complete response after chemotherapy in the FLT3-ITD/DNMT3A R882 group was 1.19±0.87, which was significantly lower than that at first diagnosis, and the difference was statistically significant (P=0.011). CONCLUSION TSPO gene may be used as an indicator of efficacy in FLT3-ITD /DNMT3A R882 double-mutated AML.
Humans ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; DNA Methyltransferase 3A ; Mutation ; Leukemia, Myeloid, Acute/drug therapy* ; Nucleophosmin ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics* ; Receptors, GABA/therapeutic use*

In contrast to the well-established genomic 5-methylcytosine (5mC), the existence of N⁶-methyladenine (6 mA) in eukaryotic genomes was discovered only recently. Initial studies found that it was actively regulated in cancer cells, suggesting its involvement in the process of carcinogenesis. However, the contribution of 6 mA in tongue squamous cell carcinoma (TSCC) still remains uncharacterized. In this study, a pan-cancer type analysis was first performed, which revealed enhanced 6 mA metabolism in diverse cancer types. The study was then focused on the regulation of 6 mA metabolism, as well as its effects on TSCC cells. To these aspects, genome 6 mA level was found greatly increased in TSCC tissues and cultured cells. By knocking down 6 mA methylases N6AMT1 and METTL4, the level of genomic 6 mA was decreased in TSCC cells. This led to suppressed colony formation and cell migration. By contrast, knockdown of 6 mA demethylase ALKBH1 resulted in an increased 6 mA level, enhanced colony formation, and cell migration. Further study suggested that regulation of the NF-κB pathway might contribute to the enhanced migration of TSCC cells. Therefore, in the case of TSCC, we have shown that genomic 6 mA modification is involved in the proliferation and migration of cancer cells.
AlkB Homolog 1, Histone H2a Dioxygenase/metabolism* ; Carcinoma, Squamous Cell/pathology* ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Humans ; Site-Specific DNA-Methyltransferase (Adenine-Specific)/metabolism* ; Tongue Neoplasms/metabolism*

BackgroundPromoter methylation of MGMT and C13ORF18 has been confirmed as a potential biomarker for early diagnosis of cervical cancer. The aim of this study was to evaluate the performance of MGMT and C13ORF18 promoter methylation for triage of cytology screening samples and explore the potential mechanism.

MethodsMethylation-sensitive high-resolution melting was used to detect promoter methylation of MGMT and C13ORF18 in 124 cervical samples. High-risk human papillomavirus (HR-HPV) was detected by the Digene Hybrid Capture 2. Gene methylation frequencies in relation to cervical intraepithelial neoplasia (CIN) were analyzed. Frequencies were compared by Chi-square tests. The expression of gene biomarkers and methylation regulators was analyzed by immunohistochemical staining, real-time fluorescence quantitative polymerase chain reaction, and Western blot.

ResultsFor triage of low-grade squamous intraepithelial lesion (LSIL), gene methylation increased specificity from 4.0% of HR-HPV detection to 30.8% of MGMT (χ = 9.873, P = 0.002) and to 50.0% of C13ORF18 (χ = 21.814, P = 0.001). For triage of atypical squamous cells of undetermined significance, HR-HPV detection had higher positive predictive value of 54.8%. Either MGMT or C13ORF18 methylation combined with HR-HPV increased the negative predictive value to 100.0% (χ = 9.757, P = 0.002). There was no relationship between MGMT and C13ORF18 expression and DNA methylation (χ = 0.776, P = 0.379 and χ = 1.411, P = 0.235, respectively). MBD2 protein level in cervical cancer was relatively lower than normal cervical tissue (t = 4.11, P = 0.006).

ConclusionsHR-HPV detection is the cornerstone for triage setting of CIN. Promoter methylation of MGMT and C13ORF18 plays a limited role in triage of LSIL. Promoter methylation of both genes may not be the causes of gene silence.

Adult ; Cervical Intraepithelial Neoplasia ; genetics ; pathology ; Chi-Square Distribution ; DNA Methylation ; genetics ; DNA Modification Methylases ; genetics ; DNA Repair Enzymes ; genetics ; Female ; Humans ; Middle Aged ; Promoter Regions, Genetic ; genetics ; Squamous Intraepithelial Lesions of the Cervix ; genetics ; pathology ; Tumor Suppressor Proteins ; genetics ; Uterine Cervical Neoplasms ; genetics ; pathology ; Young Adult

ObjectiveTo explore the inhibitory effect of polyphyllin Ⅰ (PPⅠ) on the proliferation of castration-resistant prostate cancer PC3 cells and its molecular mechanism.

METHODSWe cultured human prostate cancer PC3 cells in vitro and treated them with PPⅠ at the concentrations of 0 (blank group), 0.4, 0.8, 1.2, 1.6, 2.0, and 2.4 μmol/L for 24, 48, and 72 hours, respectively. Then we detected the proliferation of the cells by MTT assay, measured their apoptosis by flow cytometry, and determined the expressions of p-ERK1/2, ERK1/2, NF-κB/p65 and DNMT1 proteins as well as the level of NF-κB/p65 in the cells additionally treated with the ERK1/2 inhibitor SP600125 by Western blot.

RESULTSCompared with the blank control group, the PPⅠ-treated PC3 cells showed a concentration- and time-dependent reduction of the survival rate (1.00 ± 0.00 vs 0.85 ± 0.05, P < 0.01) at 0.4 μmol/L after 48 hours of intervention, concentration-dependent early apoptosis at 0.8 μmol/L (4.83 ± 0.95 vs 13.83 ± 2.97, P < 0.01), time-dependent increase of the expressions of p-ERK1/2 (1.00 ± 0.00 vs 1.73 ± 0.17, P < 0.01) and ERK1/2 (1.00 ± 0.00 vs 1.36 ± 0.12, P < 0.01) at 2 hours, and concentration-dependent decrease of the expressions of NF-κB/p65 and DNMT1 at 1.2 μmol/L (1.00 ± 0.00 vs 0.78 ± 0.10 and 0.63 ± 0.06, P < 0.01) and 1.6 μmol/L (1.00 ± 0.00 vs 0.67 ± 0.11 and 0.52 ± 0.09, P<0.01). Inhibition of ERK1/2 phosphorylation with PD98059 markedly reversed PPⅠ-induced decrease of the NF-κB/p65 expression as compared with that in the PPⅠ group (0.86 ± 0.18 vs 0.43 ± 0.09, P < 0.05).

CONCLUSIONSPPⅠ induces the early apoptosis and suppresses the proliferation of PC3 cells, probably by activating the ERK1/2 pathway and inhibiting the expressions of the NF-κB/p65 and DNMT1 proteins.

Apoptosis ; Cell Proliferation ; drug effects ; DNA (Cytosine-5-)-Methyltransferase 1 ; metabolism ; Diosgenin ; analogs & derivatives ; pharmacology ; Flavonoids ; metabolism ; Humans ; MAP Kinase Signaling System ; Male ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; NF-kappa B ; metabolism ; PC-3 Cells ; Phosphorylation ; Prostatic Neoplasms, Castration-Resistant ; drug therapy ; metabolism ; pathology ; Signal Transduction ; Transcription Factor RelA ; metabolism

Objective: To investigate the impact of FLT3-ITD and DNMT3A R882 double mutations to the prognosis of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: FLT3-ITD, DNMT3A, C-kit, CEBPA, FLT3-TKD and NPM1 mutations were detected in 206 newly diagnosed AML patients by Sanger sequencing (M(3) and those received FLT3 inhibitor were excluded). Clinical data of AML patients were retrospectively analyzed to compare the prognosis of each gene mutation group. Results: ①Of 206 patients, 104 were male and 102 female with a median age of 38 (3-63) years, including 6 cases of M(0), 24 cases of M(1), 56 cases of M(2), 39 cases of M(4), 63 cases of M(5), 6 cases of M(6) and 12 unclassified cases. ②All 206 patients were divided into four groups according to the mutation gene at the time of diagnosis: FLT3-ITD(+) DNMT3A R882(+) group (group A), FLT3-ITD(+) DNMT3A R882(-) group (group B), FLT3-ITD(-) DNMT3A R882(+) group (group C) and FLT3-ITD(-) DNMT3A R882(-) groups (group D). Gender, leukocyte count at diagnosis, chromosome karyotype, the median age, FAB classification, disease status prior to transplantation, type of donor, conditioning regimen and GVHD were not significantly different between four groups (P>0.05). ③The 2-year cumulative recurrence rate (CIR) of group A was significantly higher than that of other groups [group A (72.2±2.6)%, group B (38.6±0.6)%, group C (36.8±1.6)%, group D (27.8±0.1)%, respectively, P<0.05], while the 2-year overall survival (OS) rate and 2-year leukocyte-free survival (LFS) rate were lower than those of other groups [group A (30.9±13.3)%, (11.3±10.2)%; group B (67.5±7.8)%, (47.9±8.4)%; group C (61.4±12.4)%, (56.8±12.5)%; group D (80.1±3.7)%, (79.7±3.6)%, respectively, P<0.05]. Conclusion: AML patients with FLT3-ITD and DNMT3A R882 double mutations had a very high CIR and low OS, LFS after transplantation.
Adolescent ; Adult ; Child ; Child, Preschool ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; DNA Methyltransferase 3A ; Female ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myeloid, Acute ; Male ; Middle Aged ; Mutation ; Nucleophosmin ; Prognosis ; Retrospective Studies ; Young Adult ; fms-Like Tyrosine Kinase 3/genetics*

The occurrence and development of acute myeloid leukemia (AML) is not only related to gene mutations, but also influenced by abnormal epigenetic regulation, in which DNA methylation is one of the most important mechanisms. Abnormal DNA methylation may lead to the activation of oncogene and the inactivation of tumor suppressor gene, resulting in the occurrence of leukemia. The mutations of DNA methylation enzymes associated with AML may have certain characteristics. The AML with recurrent cytogenetic abnormalities is also related to abnormal methylation. Some fusion genes can alter DNA methylation status to participate in the pathogenesis of leukemia. In addition, chemotherapy drug resistance in patients with AML is associated with the change of gene methylation status. Considering the reversibility of the epigenetic modification, targeted methylation therapy has become a hotspot of AML research.
DNA Methylation ; drug effects ; genetics ; physiology ; DNA Modification Methylases ; genetics ; physiology ; Drug Resistance, Neoplasm ; genetics ; Epigenesis, Genetic ; genetics ; physiology ; Humans ; Leukemia, Myeloid, Acute ; etiology ; genetics ; pathology ; Mutation ; genetics

Although the traditional chemotherapy has achieved a certain effect for patients with acute myeloid leukemia (AML), but there are still limitations in terms of improving the rate of complete remission and overcome relapse after remission. The further study found that many cytogenetic molecular and epigenetic abnormalities occurred during the progression of AML, such as abnormal expression of cell surface molecules, mutation, gene aberrant methylation and so on. The drugs targeted at these changes can improve the prognosis for patients, and provide a new way for treating patients with AML. At present, the mostly targeted drugs include monoclonal antibodies CD33-Ab, tyrosine kinase inhibitor, inhibitors of DNA methyltransferases inhibitors and so on. In this review, the progress of targeted therapy in AML treatment is summarized.
Antibodies, Monoclonal ; therapeutic use ; DNA Modification Methylases ; antagonists & inhibitors ; Humans ; Leukemia, Myeloid, Acute ; drug therapy ; Mutation ; Prognosis ; Protein Kinase Inhibitors ; therapeutic use ; Remission Induction

OBJECTIVETo investigate the effect of monoamine oxidase inhibitor phenelzine on proliferation, apoptosis and histone modulation in acute lymphoblastic leukemia cell line Molt-4 cells.

METHODSThe effect of Phenelzine on cell proliferation was detected by MTT. Apoptotic rate was measured by flow cytometry. The variation of apoptosis associated proteins Caspase-3, Bcl-2 and Bax, cyclin-dependent kinase inhibitor p21, tumor suppressor protein p15, and the expression level of histone methylation of H3K4, H3K9 and histone acetylation of H3, DNMT1 were detected by Western Blot.

RESULTS① Molt-4 cell proliferation rates were (87.68±3.54)%, (67.84±3.24)%, (51.48±3.37)%, (28.72±2.56)% respectively after exposured to phenelzine at 5, 10, 15, 20 μmol/L for 24 h, P<0.05. ② After 10 μmol/L of phenelzine exposure for 24, 48, 72 h, cell proliferation rates were (67.84±3.24)%, (50.24±2.01)%, (40.31±2.25)%, P<0.05. ③ The apoptotic rates were (13.64±2.58)%, (31.24±3.42)%, (56.37±4.26)% after phenelzine treatment at 5, 10, 20 μmol/L for 24 h, which was concentration dependent. ④ Phenelzine could upregulate the expression of Bax, caspase-3, p21, and downregulate Bcl-2 expression. Phenelzine upregulated the methylation level of histone H3K4me1, H3K4me2 and histone acetylated H3, while it didn't change the level of histone H3K4me3, H3K9me1, H3K9me2. ⑤ Phenelzine inhibited DNMT1 expression and promoted p15 expression.

CONCLUSIONSPhenelzine increased the methylation of histone H3K4me1, H3K4me2, acetylation of histone H3 and p21, and decreased the expression of DNMT1 and p15, and ultimately inhibited the proliferation and apoptosis of Molt-4 cells.

Acetylation ; Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p15 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; metabolism ; Histones ; metabolism ; Humans ; Methylation ; Phenelzine ; pharmacology