Selection and identification of an ssDNA aptamer to NB4 cell.

This study was to find the aptamers with high affinity and specificity binding to acute promyelocytic leukemia (APL) NB4 cell line. These aptamers targeted NB4 cells were selected from a random single-stranded DNA (ssDNA) library of systematic evolution of ligands by exponential enrichment (CELL-SELEX). The binding rate of FITC-ssDNA library and NB4 cells was monitored using flow cytometry and fluorescence microscope. After cloned and sequenced, the structure, specificity, and affinity of these candidate aptamers were further analyzed. After a total of 19 rounds of selection, the ssDNA library was enriched and the BR (19.9%) of the 16th round was 12 times of the first round (1.6%). Three enriched aptamers were obtained from 21 positive clones of the 16th round, and the predicted secondary structures of these aptamers were mainly stem-loop. The aptamer CX9 had the highest affinity, and the equilibrium dissociation constant (Kd) was 16.2 nM. The fluorescence intensity of CX9 binding to NB4 cells was stronger than HL60 and K562 cells under fluorescence microscopy. The study indicates that aptamer CX9 exhibits high affinity and specificity with NB4 cells and lay a foundation for the rapid diagnostic method to detect APL with fluorescence-labeled aptamer.

6-Gingerol modulates miRNAs and PODXL gene expression via methyltransferase enzymes in NB4 cells: an in silico and in vitro study.

This investigation delves into the influence of predicted microRNAs on DNA methyltransferases (DNMTs) and the PODXL gene within the NB4 cell line, aiming to elucidate their roles in the pathogenesis of acute myeloid leukemia (AML). A comprehensive methodological framework was adopted to explore the therapeutic implications of 6-gingerol on DNMTs. This encompassed a suite of bioinformatics tools for protein structure prediction, docking, molecular dynamics, and ADMET profiling, alongside empirical assessments of miRNA and PODXL expression levels. Such a multifaceted strategy facilitated an in-depth understanding of 6-gingerol's potential efficacy in DNMT modulation. The findings indicate a nuanced interplay where 6-gingerol administration modulated miRNA expression levels, decreasing in DNMT1 and DNMT3A expression in NB4 cells. This alteration indirectly influenced PODXL expression, contributing to the manifestation of oncogenic phenotypes. The overexpression of DNMT1 and DNMT3A in NB4 cells may contribute to AML, which appears modulable via microRNAs such as miR-193a and miR-200c. Post-treatment with 6-gingerol, DNMT1 and DNMT3A expression alterations were observed, culminating in the upregulation of miR-193a and miR-200c. This cascade effect led to the dysregulation of tumor suppressor genes in cancer cells, including downregulation of PODXL, and the emergence of cancerous traits. These insights underscore the therapeutic promise of 6-gingerol in targeting DNMTs and microRNAs within the AML context.

[Mechanism of Proliferation and Apoptosis of Acute Promyelocytic Leukemia Cell Line NB4 Induced by TPA].

OBJECTIVE: To investigate the effect of phorbol-12-myristate-13-ace-tate (TPA) on the proliferation and apoptosis of acute promyelocytic leukemia cell line NB4 and its molecular mechanism. METHODS: The effect of different concentrations of TPA on the proliferation of NB4 cells at different time points was detected by CCK-8 assay. The morphological changes of NB4 cells were observed by Wright-Giemsa staining. The cell cycle and apoptosis of NB4 cells after TPA treatment were detected by flow cytometry. The mRNA expressions of NB4 cells after TPA treatment were analyzed by high-throughput microarray analysis and real-time quantitative PCR. Western blot was used to detect the protein expression of CDKN1A, CDKN1B, CCND1, MYC, Bax, Bcl-2, c-Caspase 3, c-Caspase 9, PIK3R6, AKT and p-AKT. RESULTS: Compared with the control group, TPA could inhibit the proliferation of NB4 cells, induce the cells to become mature granulocyte-monocyte differentiation, and also induce cell G1 phase arrest and apoptosis. Differentially expressed mRNAs were significantly enriched in PI3K/AKT pathway. TPA treatment could increase the mRNA levels of CCND1, CCNA1, and CDKN1A, while decrease the mRNA level of MYC. It could also up-regulate the protein levels of CDKN1A, CDKN1B, CCND1, Bax, c-Caspase 3, c-Caspase 9, and PIK3R6, while down-regulate MYC, Bcl-2, and p-AKT in NB4 cells. CONCLUSION: TPA induces NB4 cell cycle arrest in G1 phase and promotes its apoptosis by regulating PIK3/AKT signaling pathway.

Transcriptional and Metabolic Dissection of ATRA-Induced Granulocytic Differentiation in NB4 Acute Promyelocytic Leukemia Cells.

Acute promyelocytic leukemia (APL) is a hematological disease characterized by a balanced reciprocal translocation that leads to the synthesis of the oncogenic fusion protein PML-RARα. APL is mainly managed by a differentiation therapy based on the administration of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). However, therapy resistance, differentiation syndrome, and relapses require the development of new low-toxicity therapies based on the induction of blasts differentiation. In keeping with this, we reasoned that a better understanding of the molecular mechanisms pivotal for ATRA-driven differentiation could definitely bolster the identification of new therapeutic strategies in APL patients. We thus performed an in-depth high-throughput transcriptional profile analysis and metabolic characterization of a well-established APL experimental model based on NB4 cells that represent an unevaluable tool to dissect the complex mechanism associated with ATRA-induced granulocytic differentiation. Pathway-reconstruction analysis using genome-wide transcriptional data has allowed us to identify the activation/inhibition of several cancer signaling pathways (e.g., inflammation, immune cell response, DNA repair, and cell proliferation) and master regulators (e.g., transcription factors, epigenetic regulators, and ligand-dependent nuclear receptors). Furthermore, we provide evidence of the regulation of a considerable set of metabolic genes involved in cancer metabolic reprogramming. Consistently, we found that ATRA treatment of NB4 cells drives the activation of aerobic glycolysis pathway and the reduction of OXPHOS-dependent ATP production. Overall, this study represents an important resource in understanding the molecular "portfolio" pivotal for APL differentiation, which can be explored for developing new therapeutic strategies.

Adhesion of human monocytes to oxygen- and nitrogen- containing plasma polymers: Effect of surface chemistry and protein adsorption.

The interactions between monocytes and biomaterials can potentially be modulated by controlling the chemical and structural surface properties of biomaterials. The objective of this study was to determine the effect of plasma-deposited functional organic coatings on monocyte adhesion and differentiation into macrophages. Organic coatings with varying oxygen and nitrogen concentration were prepared by low-pressure plasma co-polymerization of binary gas mixtures combining a hydrocarbon (butadiene/ethylene) and a heteroatom-containing gas (carbon dioxide/ammonia) to deposit either oxygen or nitrogen-containing coatings. The deposition parameters controlled the composition of the coatings and, consequently, the surface charge (between 26 mV and -28 mV) and wettability. The adhesion of myeloid leukemia cell lines U937 and NB4 as well as human monocytes to plasma polymerized coatings, was tested using cell culture medium with and without fetal bovine serum. The results showed that the concentration of [-NH2] and [-COOH] on the surface of the plasma polymers, controls the adhesion of U937 and NB4 cell lines to the coatings. Thus, above a certain composition threshold, i.e. [-NH2]=2.6-3.0% and [-COOH]=1.2-1.57 nmol/cm2, the surface facilitates adhesion of both cell lines, irrespective of the culture medium used. Based on qualitative observations the number of monocytes adhering to the coatings was proportional to the concentration of functional groups at the surface of the coatings. The surface plasmon resonance results, in line with cell culture experiments, indicated that the presence of albumin on the surfaces with [-NH2] and [-COOH] above the determined critical concentration may be an indicator of monocyte adhesion to these plasma polymers.

The effect of simultaneous administration of arsenic trioxide and microvesicles derived from human bone marrow mesenchymal stem cells on cell proliferation and apoptosis of acute myeloid leukemia cell line.

Acute Promyelocytic Leukemia is one of the most prevalent forms of leukemia which has been treated with arsenic trioxide (ATO) and/or all-trans retinoic acid (ATRA). Although, ATRA and ATO are broadly accessible and administrated, some adverse side effects have been reported recently. Nowadays, microvesicles (MVs) are considered as a potential therapeutic agent. Their capacity to alter the behavior of the cells is one of the most controversial issues. In this study, we investigated apoptotic effects of MVs derived from human bone marrow mesenchymal stem cells (hBM-MSCs) in combination with ATO on NB4 cell line. MVs were isolated by ultra-centrifugation. After 7 days, MTT assay, Annexin-V-fluorescein staining assay and RT-qPCR for BCL-2, KI67, BAX genes expression were performed. The results showed lower cell viability rate, higher apoptosis ratio, higher BAX gene, and lower KI67 and BCL-2 genes' expression in cells exposed to MVs in combination with ATO compared to cells treated with each agent alone and non-treated control. We showed that MVs in combination with ATO had more apoptotic effect on NB4 cell line than each agent alone. MVs in combination with ATO in APL treatment might play an effective therapeutic role with fewer adverse side effects compared to any other agents.

Changes of Apolipoprotein M Gene Expression During the Cell Differentiation and Apoptosis Induced by Simvastatin in Combination with All-Trans Retinoic Acid in Human Promyelocytic Leukemia Cell Line NB4.

We examined the effect of simvastatin (SV) alone and in combination with all-trans retinoic acid (ATRA) on proliferation, differentiation, apoptosis and apolipoprotein M (apoM) expression in the human promyelocytic leukemia cell line NB4. The NB4 cells were incubated with 10 µM Simvastatin (10SV) and 0.5 µM ATRA alone or in combination, taking NB4 cells without any treatment as normal controls. The cells of different groups were collected at 24, 48 and 72 h post-incubation for further detection. Their morphological changes were observed after Wright stain. MTT method was used to assay the growth inhibition rate and flow cytometry to detect CD11b expression level and the early stage apoptosis ratio. Real-time quantitative reverse transcriptase-polymerase chain reaction was used to detect the apoM gene expression levels. As expected 0.5 µM ATRA did not affect proliferation or apoptosis, strongly induced differentiation and decreased apoM expression. 10SV inhibited proliferation, increased apoptosis, induced differentiation and increased apoM expression in a time-dependent manner. The addition of ATRA to SV did not increase the effect of SV on proliferation and apoptosis, but increased the effect of SV on differentiation. And completely abrogated the effect of SV on apoM expression. Together these results show that SV has anti-leukemic properties by itself and that combined therapy may have a place in the current anti-leukemic arsenal.

Chemosensitivity enhancement toward arsenic trioxide by inhibition of histone deacetylase in NB4 cell line.

OBJECTIVE: To investigate the cytotoxic effects of suberanilohydroxamic acid (vorinostat) in combination with arsenic trioxide (ATO) on the human NB4 cell line in vitro. METHODS: The rates of cell proliferation following treatment with vorinostat with or without ATO were measured. Flow cytometry of Annexin-V/propidium iodide double-stained cells was used to measure apoptosis. Acridine Orange and ethidium bromide staining was used to observe morphological changes characteristic of apoptosis. Western blot analysis was used to measure protein levels. RESULTS: Vorinostat and ATO, alone and in combination, inhibited the proliferation of NB4 cells in a time- and dose-dependent manner and the effect was additive. NB4 cells treated with vorinostat + ATO demonstrated greater levels of apoptosis compared with cells treated with either drug alone. Both vorinostat and ATO alone and in combination resulted in lower levels of promyelocytic leukaemia/retinoic acid receptor alpha fusion protein and increased levels of acetyl-histone H3 and acetyl-histone H4 proteins compared with controls. Vorinostat + ATO resulted in lower levels of Akt protein compared with either drug alone. CONCLUSION: The combination of vorinostat and ATO inhibited cell proliferation, induced apoptosis, and enhanced the chemosensitivity of NB4 cells. The mechanism might be associated with increasing histone acetylation levels as well as downregulation of the Akt signalling pathway.

Suppressive effects of simvastatin on the human acute promyelocytic leukemia NB4 cell line through the regulation of the nuclear factor-κB signaling pathway.

The present study examined the effects of simvastatin on the proliferation, apoptosis and gene expression levels involved in the nuclear factor-κB (NF-κB) signaling pathway in the human acute promyelocytic leukemia NB4 cell line by methyl thiazolyl tetrazolium assay, flow cytometry and the Human NF-κB Signaling Pathway RT2 Profiler™ PCR Array profiles. The results showed that simvastatin significantly inhibited proliferation and induced apoptosis of the NB4 cells in a time- and dose-dependent manner. Changes were noted in the expression levels of 56 genes involved in the NF-κB signaling pathways in the NB4 cells treated with 15 µm simvastatin at 48 h post-incubation, among which, 47 genes were downregulated and 9 were upregulated. In conclusion, simvastatin potentially inhibits the proliferation and induces the apoptosis of NB4 cells through the regulation of the expression levels of genes involved in the NF-κB signaling pathway.

A novel acidic serine protease, ASPNJ inhibits proliferation, induces apoptosis and enhances chemo-susceptibility of acute promyelocytic leukemia cell.

Acidic serine protease (ASPNJ) purified from Neanthes japonica, is a fibrinolytic enzyme. Earthworm fibrinolytic enzyme has been recently reported with anti-tumor activity on human hepatoma cells. To investigate if ASPNJ play therapeutic effects on emergent blood cancer, acute promyelocytic leukemia (APL), we tested the effects of ASPNJ on APL cell line NB4. Our results showed that ASPNJ inhibited the growth of NB4 cells in a dose and time dependent manner. Cell apoptosis was induced by ASPNJ with obvious morphological changes. The sensitivity of cells to cytarabine and doxorubicin were greatly increased respectively by combination with ASPNJ. In contrast to inhibitory effects on NB4 cells, ASPNJ showed much less effect on normal human neutrophils survival. There were no effects of hemolysis and agglutination observed on normal human erythrocytes following ASPNJ treatment. Conclusively, our data suggest that ASPNJ may become a new candidate for leukemia therapeutic approaches.