p110CUX1 promotes acute myeloid leukemia progression via regulating pyridoxal phosphatase expression and activating PI3K/AKT/mTOR signaling pathway.

As an evolutionarily conserved transcription factor, Cut-like homeobox 1 (CUX1) plays crucial roles in embryonic and nervous system development, cell differentiation, and DNA damage repair. One of its major isoforms, p110CUX1, exhibits stable DNA binding capabilities and contributes to the regulation of cell cycle progression, proliferation, migration, and invasion. While p110CUX1 has been implicated in the progression of various malignant tumors, its involvement in acute myeloid leukemia (AML) remains uncertain. This study aims to elucidate the role of p110CUX1 in AML. Our findings reveal heightened expression levels of both p110CUX1 and pyridoxal phosphatase (PDXP) in AML cell lines. Overexpression of p110CUX1 promotes AML cell proliferation while inhibiting apoptosis and differentiation, whereas knockdown of PDXP yields contrasting effects. Mechanistically, p110CUX1 appears to facilitate AML development by upregulating PDXP expression and activating the PI3K/AKT/mTOR signaling pathway. Animal experimental corroborate the pro-AML effect of p110CUX1. These results provide experimental evidence supporting the involvement of the p110CUX1-PDXP-PI3K/AKT/mTOR axis in AML progression. Hence, targeting p110CUX1 may hold promise as a therapeutic strategy for AML.

Comparison of Mycoplasma pneumoniae infection in children admitted with community acquired pneumonia before and during the COVID-19 pandemic: a retrospective study at a tertiary hospital of southwest China.

PURPOSE: The COVID-19 pandemic has notably altered the infection dynamics of various pathogens. This study aimed to evaluate the pandemic's impact on the infection spectrum of Mycoplasma pneumoniae (M. pneumoniae) among children with community acquired pneumonia (CAP). METHODS: We enrolled pediatric CAP patients admitted to a tertiary hospital in southwest China to compare the prevalence and characteristics of M. pneumoniae infections before (2018-2019) and during (2020-2022) the COVID-19 pandemic. Detection of M. pneumoniae IgM antibodies in serum were conducted using either indirect immunofluorescence or passive agglutination methods. RESULTS: The study included 1505 M. pneumoniae-positive and 3160 M. pneumoniae-negative CAP patients. Notable findings were the higher age and frequency of pneumonia-associated symptoms in M. pneumoniae-positive patients, alongside a lower male proportion and fewer respiratory co-infections. The year 2019 saw a notable increase in M. pneumoniae infections compared to 2018, followed by a decline from 2020 to 2022. The COVID-19 pandemic period witnessed significant alterations in age distribution, male proportion, and co-infections with specific pathogens in both M. pneumoniae-positive and negative patients. The M. pneumoniae infections were predominantly seasonal, peaking in autumn and winter during 2018 and 2019. Although there was a sharp drop in February 2020, the infection still peaked in cold months of 2020 and 2021. However, the typical seasonal pattern was nearly absent in 2022. CONCLUSIONS: The COVID-19 pandemic has markedly changed the infection landscape of M. pneumoniae in pediatric CAP patients, with shifts observed in infection rates, demographic profiles, co-infections, and seasonal patterns.

Changes in the epidemiology and antimicrobial resistance patterns of Streptococcus pneumoniae from pediatric community acquired pneumonia patients attended in a Chinese hospital during the COVID-19 pandemic.

PURPOSE: The COVID-19 pandemic has altered the infection dynamics of numerous pathogens. This study aimed to elucidate its impact on Streptococcus pneumoniae (S. pneumoniae) infections in children with community acquired pneumonia (CAP). METHODS: A retrospective analysis was conducted in pediatric CAP patients admitted before (2018-2019) and during (2020-2022) the COVID-19 pandemic. The epidemiology and antimicrobial resistance (AMR) patterns of S. pneumoniae were compared to reveal the impact of the pandemic. RESULTS: A total of 968 S. pneumoniae-associated pediatric CAP patients were enrolled. Although the positivity rate and gender of patients were stable across both periods, the age notably increased in 2021 and 2022. Additionally, significant changes were observed in the co-infections with several pathogens and the resistance rates to certain antibiotics during the COVID-19 pandemic. The resistance rate to clindamycin and quinupristin-dalfopristin increased, whereas the resistance rate to tetracycline, trimethoprim-sulfamethoxazole, telithromycin, and proportion of multi-drug resistant isolates decreased. The number of S. pneumoniae strains and resistant isolates exhibited similar seasonal patterns in 2018 and 2019, peaking in November or December with another minor peak in March or April. During the COVID-19 pandemic, there was a sharp decrease in February 2020 and no resurgence was observed at the end of 2022. Additionally, the minor peak was absent in 2020 and shifted to other months in 2021 and 2022. CONCLUSIONS: The COVID-19 pandemic has markedly altered the infection spectrum of S. pneumoniae in pediatric CAP patients, as evidenced by shifts in the age of patients, respiratory co-infections, AMR patterns, and seasonal trends.

A Mendelian randomization study: physical activities and chronic kidney disease.

Increasing evidence has shown that physical activity is related to a lower risk of chronic kidney disease (CKD), thus indicating a potential target for prevention. However, the causality is not clear; specifically, physical activity may protect against CKD, and CKD may lead to a reduction in physical activity. Our study examined the potential bidirectional relationship between physical activity and CKD by using a genetically informed method. Genome-wide association studies from the UK Biobank baseline data were used for physical activity phenotypes and included 460,376 participants. For kidney function (estimated Glomerular Filtration Rate (eGFR) and CKD, with eGFR < 60 mL/min/1.73 m2), CKDGen Consortium data were used, which included 480,698 CKD participants of European ancestry. Mendelian randomization (MR) analysis was used to determine the causal relationship between physical activities and kidney function. Two-sample MR genetically predicted that heavy DIY (do it yourself) (e.g., weeding, lawn mowing, carpentry, and digging) decreased the risk of CKD (odds ratio [OR] = 0.287, 95% CI = 0.117-0.705, p = 0.0065) and improved the level of eGFR (ß = 0.036, 95% CI = 0.005-0.067, p = 0.021). The bidirectional MR showed no reverse causality. It is worth noting that other physical activities, such as walking for pleasure, strenuous sports, light DIY (e.g., pruning and watering the lawn), and other exercises (e.g., swimming, cycling, keeping fit, and bowling), were not significantly correlated with CKD and eGFR. This study used genetic data to provide reliable and robust causal evidence that heavy physical activity (e.g., weeding, lawn mowing, carpentry, and digging) can protect kidney function and further lower the risk of CKD.

ZNF460-regulated COMMD7 Promotes Acute Myeloid Leukemia Proliferation Via the NF-κB Signaling Pathway.

Acute myeloid leukemia (AML) is a malignancy of the hematological system, for which there remains an urgent need for new therapeutic and diagnostic targets. COMM domain containing 7 (COMMD7) is a recently-identified oncogene linked to poor prognosis in AML. COMMD7 regulates multiple signaling pathways, including nuclear factor-kappa B (NF-κB) signaling. Here, we report that COMMD7 is highly expressed in the AML cell lines KG1a and U937 and that its inhibition by shRNA reduced proliferation, promoted apoptosis and facilitated cell cycle arrest in the G2/M phase in relation to depression of the NF-κB pathway. Furthermore, zinc finger protein 460 (ZNF460) is overexpressed in AML and regulates COMMD7. We found that knockdown of ZNF460 downregulated the expression of COMMD7 while the NF-κB pathway was also inhibited. In addition, we noticed that knockdown of ZNF460 reduced proliferation and increased apoptosis rate of AML cells and that the cell cycle was blocked in the G2/M phase. In brief, our results revealed a critical effect of the ZNF460-COMMD7-NF-κB axis for the proliferation of AML cells. Therefore, COMMD7 may be a possible therapeutic target for AML.

Ultrasensitive detection of genetic variation based on dual signal amplification assisted by isothermal amplification and cobalt oxyhydroxide nanosheets/quantum dots.

PML/RARα fusion gene (P/R) is the characteristic signature genetic variation of acute promyelocytic leukemia (APL). Here, by integrating triple-stranded DNA hybridization-triggered strand displacement amplification (tri-HT SDA) and cobalt oxyhydroxide nanosheets/quantum dots (CoOOH/QD)-based amplification, we constructed a novel biosensor of easy-operating, time-saving and high sensitivity for detecting P/R to meet clinical needs. Owing to the specific recognition and efficient amplification of tri-HT SDA as well as impressive anti-interference and considerable amplification of CoOOH/QD, this biosensor demonstrated a wide dynamic range (10 fM to 10 nM) with a low limit of detection (5.50 fM) in P/R detection. Additionally, this biosensor could detect P/R spiked into human serum with good recoveries and relative standard deviation (RSD), thus potentially exhibiting ultrasensitive and specific nuclear acid sequence detection ability in clinical diagnosis owing to combing isothermal amplification and nanomaterials.

miRNA-222-3p enhances the proliferation and suppresses the apoptosis of acute myeloid leukemia cells by targeting Axin2 and modulating the Wnt/ß-catenin pathway.

MicroRNA (miRNA)-222-3p is overexpressed in numerous tumors, where it acts as an oncogene. Although miRNA-222 is highly expressed in acute myeloid leukemia (AML), its functions and the mechanisms underlying these functions have not yet been fully elucidated. This study aimed to investigate the regulatory roles of miRNA-222-3p in AML and the molecular mechanisms underlying these roles. In this study, we observed that miRNA-222-3p increased the viability and suppressed the apoptosis of AML cells. Axin2 was demonstrated to be a direct target of miRNA-222-3p, which when overexpressed, inhibited Axin2 expression and stimulated the Wnt/ß-catenin pathway. In contrast, upregulation of Axin2 expression levels reduced the viability and enhanced the apoptosis of AML cells. Moreover, it partially reversed the effects of the miRNA-222-3p mimic on the proliferation and apoptosis of, and modulation of the Wnt/ß-catenin pathway in, AML cells. Taken together, this study provides strong evidence that miRNA-222-3p can serve as a molecular target for AML treatment.

Distinct immune responses in the early phase to natural SARS-CoV-2 infection or vaccination.

Immune responses elicited by viral infection or vaccination play key roles in the viral elimination and the prevention of reinfection, as well as the protection of healthy persons. As one of the most widely used Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, there have been increasing concerns about the necessity of additional doses of inactivated vaccines, due to the waning immune response several months after vaccination. To further optimize inactivated SARS-CoV-2 vaccines, we compared immune responses to SARS-CoV-2 elicited by natural infection and immunization with inactivated vaccines in the early phase. We observed the lower antibody levels against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in the early phase of postvaccination with a slow increase, compared to the acute phase of SARS-CoV-2 natural infection. Specifically, IgA antibodies have the most significant differences. Moreover, we further analyzed cytokine expression between these two groups. A wide variety of cytokines presented high expression in the infected individuals, while a few cytokines were elicited by inactivated vaccines. The differences in antibody responses and cytokine levels between natural SARS-CoV-2 infection and vaccination with the inactivated vaccines may provide implications for the optimization of inactivated SARS-CoV-2 vaccines and the additional application of serological tests.

DNMT3A R882H mutation drives daunorubicin resistance in acute myeloid leukemia via regulating NRF2/NQO1 pathway.

BACKGROUND: DNA methyltransferase 3A (DNMT3A) often mutate on arginine 882 (DNMT3AR882) in acute myeloid leukemia (AML). AML patients with DNMT3A R882 mutation are usually resistant to daunorubicin treatment; however, the associated mechanism is still unclear. Therefore, it is urgent to investigate daunorubicin resistance in AML patients with DNMT3A R882 mutant. METHOD: AML cell lines with DNMT3A-wild type (DNMT3A-WT), and DNMT3A-Arg882His (DNMT3A-R882H) mutation were constructed to investigate the role of DNMT3A R882H mutation on cell proliferation, apoptosis and cells' sensitivity to Danunorubin. Bioinformatics was used to analyze the role of nuclear factor-E2-related factor (NRF2) in AML patients with DNMT3A R882 mutation. The regulatory mechanism of DNMT3A R882H mutation on NRF2 was studied by Bisulfite Sequencing and CO-IP. NRF2 inhibitor Brusatol (Bru) was used to explore the role of NRF2 in  AML cells carried DNMT3A R882H mutation. RESULTS: AML cells with a DNMT3A R882H mutation showed high proliferative and anti-apoptotic activities. In addition, mutant cells were less sensitive to daunorubicin and had a higher NRF2 expression compared with those in WT cells. Furthermore, the NRF2/NQO1 pathway was activated in mutant cells in response to daunorubicin treatment. DNMT3A R882H mutation regulated the expression of NRF2 via influencing protein stability rather than decreasing methylation of NRF2 promoter. Also, NRF2/NQO1 pathway inhibition improved mutant cells' sensitivity to daunorubicin significantly. CONCLUSION: Our findings identified NRF2 as an important player in the regulation of cell apoptosis through which helps mediate chemoresistance to daunorubicin in AML cells with DNMT3A R882H mutation. Targeting NRF2 might be a novel therapeutic approach to treat AML patients with a DNMT3A R882H mutation. Video abstract.

MiRNA-301b-3p induces proliferation and inhibits apoptosis in AML cells by targeting FOXF2 and regulating Wnt/ß-catenin axis.

BACKGROUND: MiRNA-301b-3p functions as an oncomiRNA or tumor suppressor, and has been reported in various cancer types, including pancreatic, colorectal, oral, hepatocellular and lung cancers. Although the expression of miRNA-301b-3p is upregulated in acute myeloid leukemia (AML), its biological function and precise mechanisms remain unclarified. This study explores the roles of miRNA-301b-3p in AML, with the aim of ascertaining its regulatory action on Wnt/ß-catenin axis by targeting Forkhead box F2 (FOXF2). METHODS: The expression levels of miRNA-301b-3p and FOXF2 were measured by quantitative real-time PCR. The effects of miRNA-301b-3p knockdown and overexpression on cell proliferation were evaluated by CCK8 and cell counting assays, while cell apoptosis was analyzed by flow cytometry. The expression levels of apoptosis-related proteins, including FOXF2, and other targets in Wnt/ß-catenin axis were determined by immunoblotting. Possible interaction between miRNA-301-3p and FOXF2 in AML cells was examined by luciferase reporter assays. RESULTS: MiRNA-301b-3p was dramatically upregulated in AML cells, and showed a negative correlation with FOXF2 expression. Downregulation of miRNA-301b-3p suppressed proliferation and promoted apoptosis in AML cells. MiRNA-301b targeted FOXF2 to regulate Wnt/ß-catenin axis. In the rescue experiments, FOXF2 overexpression partly reversed the effect of miRNA-301b-3p mimic in AML cells. CONCLUSION: The current findings demonstrate that miRNA-301b-3p targets FOXF2 to induce proliferation and inhibit apoptosis in AML cells via regulation of Wnt/ß-catenin axis.

ZFP91 promotes cell proliferation and inhibits cell apoptosis in AML via inhibiting the proteasome-dependent degradation of RIP1.

Acute myeloid leukemia (AML) is a quickly progressive and devastated hematological malignancy with large rate of relapse and the appearance of chemotherapy resistance. Therefore, the identification of new therapeutic targets is urgent. ZFP91 is a hidden oncogene. Nevertheless, how ZFP91 takes part in regulating AML is less clear. Our research aims at investigating the molecular mechanisms and uncovering the effects of ZFP91 on AML. This research demonstrates that ZFP91 boosts AML cell proliferation and stops AML cell apoptosis. Mechanistically, experimental results showed the interaction between ZFP91 and RIP1 and inhibitory effect of ZFP91 on the K48-linked ubiquitination of endogenous RIP1, which is an important molecule in AML. Taken together, our results provide the evidence that targeted inhibition of ZFP91 could be a hopeful measure to treat AML.

RIP1-dependent Apoptosis and Differentiation Regulated by Skp2 and Akt/GSK3ß in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous neoplasm characterized by variations in cytogenetics and molecular abnormalities, which result in variable response to therapy. Receptor-interacting serine/threonine kinase 1 (RIP1)-mediated necroptosis has been reported to have a potential role in the treatment of AML. We obtained Skp2 and RIP1 are significantly overexpressed in AML samples using original published data, and identified that Skp2-depletion in AML cells significantly suppressed RIP1. Functional analysis showed that the inhibition of RIP1 caused by necrostatin-1 (Nec-1) inhibited the proliferation, simultaneously facilitate both the apoptosis and differentiation of AML cells. Mechanistical analysis elucidated that knockdown of Skp2 suppresses RIP1 by transcriptional regulation but not by proteasome degradation. Additionally, Skp2 regulated the function of RIP1 by decreasing K63-linked ubiquitin interaction with RIP1. Moreover, the suppression of Akt/GSK3ß was observed in Skp2 knockdown stable NB4 cells. Also, GSK3ß inactivation via small-molecule inhibitor treatment remarkably decreased RIP1 level. RIP1 regulates differentiation by interacting with RARα, increasing RA signaling targets gene C/EBPα and C/EBPß. In conclusion, our study provides a novel insight into the mechanism of tumorigenesis and the development of AML, for which the Skp2-Akt/GSK3ß-RIP1 pathway can be developed as a promising therapeutic target.

A Peptide-Based Magnetic Chemiluminescence Enzyme Immunoassay for Serological Diagnosis of Coronavirus Disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel ß-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection. METHODS: In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2. RESULTS: To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively. CONCLUSIONS: Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.

NLS-RARα blocks cell differentiation by inhibiting the retinoic acid signalling pathway.

A majority of acute promyelocytic leukaemia (APL) cases are characterized by the PML-RARα fusion gene. Previous studies have shown that neutrophil elastase (NE) can cleave PML-RARα and is important for the development of APL. Here, we demonstrate that one of the cleavage products of PML-RARα, NLS-RARα, can block cell differentiation by repressing the expression of the target genes within the retinoic acid signalling pathway. The results of reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot analysis showed that NLS-RARα depressed the expression of the cell differentiation marker protein, CD11b and CEBPß, as well as the retinoic acid signalling pathway target genes, RARß and CEBPε. Studies have shown that NLS-RARα forms heterodimers with retinoid X receptor α(RXRα) and interacts with SMRT. When treated with all-trans retinoic acid (ATRA), NLS-RARα exhibits diminished transcriptional activity compared to RARα. Moreover, in the presence of high doses of ATRA, NLS-RARα could be degraded along with the consequent transactivation of retinoic acid signalling pathway target genes and cell differentiation induction in a dose- and time-dependent manner. Together, these results indicate that NLS-RARα blocks cell differentiation by inhibiting the retinoic acid signalling pathway.

GSK-J4 induces cell cycle arrest and apoptosis via ER stress and the synergism between GSK-J4 and decitabine in acute myeloid leukemia KG-1a cells.

BACKGROUND: GSK-J4 is the inhibitor of H3K27me3 demethylase. Recent studies demonstrated that GSK-J4 could affect the proliferation and apoptosis of a variety of cancer cells. However, the effects and underlying mechanisms of GSK-J4 on the proliferation and apoptosis of human acute myeloid leukemia (AML) KG-1a cells have not been explored thoroughly. METHODS: The effect of GSK-J4 on cell proliferation was assessed with CCK8, while cell cycle distribution and apoptosis were analyzed using flow cytometry. The proteins related to cell cycle, cell apoptosis, endoplastic reticulum (ER) stress and PKC-α/p-Bcl2 pathway were detected by Western blotting. The expression level of PKC-α mRNA was measured by quantitative real-time PCR.ER stress inhibitor 4-phenyl butyric acid (4-PBA) was used to explore the role of ER stress in GSK-J4 induced cell-cycle arrest and cell apoptosis. The combination effects of Decitabine and GSK-J4 on KG-1a cells proliferation and apoptosis were also evaluated by CCK8, flow cytometry and immunoblot analysis. RESULTS: GSK-J4 reduced cell viability and arrested cell cycle progression at the S phase by decreasing the expression of CyclinD1 and CyclinA2 and increasing that of P21. Moreover, GSK-J4 enhanced the expression of apoptosis-related proteins (cle-caspase-9 and bax) and inhibited PKC-a/p-Bcl2 pathway to promote cell apoptosis. In addition, ER stress-related proteins (caspase-12, GRP78 and ATF4) were increased markedly after exposure to GSK-J4. The effects of GSK-J4 on cell cycle, apoptosis and PKC-a/p-Bcl2 pathway were attenuated after treatment with ER stress inhibitor. Furthermore, decitabine could significantly inhibit the proliferation and induce the apoptosis of KG-1a cells after combined treatment with GSK-J4. CONCLUSION: Taken together, this study provided evidence that ER stress could regulate the process of GSK-J4-induced cell cycle arrest, cell apoptosis and PKC-α/p-bcl2 pathway inhibition and demonstrated a potential combinatory effect of decitabine and GSK-J4 on leukemic cell proliferation and apoptosis.

A novel P53/POMC/Gαs/SASH1 autoregulatory feedback loop activates mutated SASH1 to cause pathologic hyperpigmentation.

p53-Transcriptional-regulated proteins interact with a large number of other signal transduction pathways in the cell, and a number of positive and negative autoregulatory feedback loops act upon the p53 response. P53 directly controls the POMC/α-MSH productions induced by ultraviolet (UV) and is associated with UV-independent pathological pigmentation. When identifying the causative gene of dyschromatosis universalis hereditaria (DUH), we found three mutations encoding amino acid substitutions in the gene SAM and SH3 domain containing 1 (SASH1), and SASH1 was associated with guanine nucleotide-binding protein subunit-alpha isoforms short (Gαs). However, the pathological gene and pathological mechanism of DUH remain unknown for about 90 years. We demonstrate that SASH1 is physiologically induced by p53 upon UV stimulation and SASH and p53 is reciprocally induced at physiological and pathophysiological conditions. SASH1 is regulated by a novel p53/POMC/α-MSH/Gαs/SASH1 cascade to mediate melanogenesis. A novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. Our study demonstrates that a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype.

p53 regulates ERK1/2/CREB cascade via a novel SASH1/MAP2K2 crosstalk to induce hyperpigmentation.

We previously reported that three point mutations in SASH1 and mutated SASH1 promote melanocyte migration in dyschromatosis universalis hereditaria (DUH) and a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. However, the underlying mechanism of molecular regulation to cause this hyperpigmentation disorder still remains unclear. In this study, we aimed to investigate the molecular mechanism undergirding hyperpigmentation in the dyschromatosis disorder. Our results revealed that SASH1 binds with MAP2K2 and is induced by p53-POMC-MC1R signal cascade to enhance the phosphorylation level of ERK1/2 and CREB. Moreover, increase in phosphorylated ERK1/2 and CREB levels and melanogenesis-specific molecules is induced by mutated SASH1 alleles. Together, our results suggest that a novel SASH1/MAP2K2 crosstalk connects ERK1/2/CREB cascade with p53-POMC-MC1R cascade to cause hyperpigmentation phenotype of DUH.

Verteporfin Inhibits Cell Proliferation and Induces Apoptosis in Human Leukemia NB4 Cells without Light Activation.

Background and Aims: Verteporfin (VP), clinically used in photodynamic therapy for neovascular macular degeneration, has recently been proven a suppressor of yes-associated protein (YAP) and has shown potential in anticancer treatment. However, its anti-human leukemia effects in NB4 cells remain unclear. In this study, we investigated the effects of VP on proliferation and apoptosis in human leukemia NB4 cells. Methods: NB4 cells were treated with VP for 24 h. The effects of VP on cell proliferation were determined using a Cell-Counting Kit-8 assay (CCK-8) assay and colony forming assay. Apoptosis and cell cycle were evaluated by flow cytometry (FCM). The protein levels were detected by western blot. Results: We found that VP inhibited the proliferation of NB4 cells in a concentration and time-dependent manner. FCM analysis showed that VP induced apoptosis in a concentration dependent manner and that VP treatment led to cell cycle arrest at G0/G1 phase. Moreover, VP significantly decreased the protein expression of YAP, p-YAP, Survivin, c-Myc, cyclinD1, p-ERK, and p-AKT. In addition, VP increased the protein expression of cleaved caspase3, cleaved PARP, Bax, and p-p38 MAPK. Conclusions: VP inhibited the proliferation and induced apoptosis in NB4 cells.

Effect of YAP Inhibition on Human Leukemia HL-60 Cells.

Background: Yes-associated protein (YAP), the nuclear effector of the Hippo pathway, is a candidate oncoprotein and participates in the progression of various malignancies. However, few reports have examined the effect of YAP inhibition in human leukemia HL-60 cells. Methods: We examined the effects of YAP knockdown or inhibition using short hairpin RNA (shRNA) or verteporfin (VP), respectively. Western blot assays were used to determine the expression levels of YAP, Survivin, cyclinD1, PARP, Bcl-2, and Bax. Cell proliferation was assessed using the cell counting kit (CCK-8) assay. Cell cycle progression and apoptosis were evaluated by flow cytometry, and apoptotic cell morphology was observed by Hoechst 33342 staining. Results: Knockdown or inhibition of YAP led to cell cycle arrest at the G0/G1 phase and increased apoptosis, inhibited cell proliferation, increased levels of Bax and cleaved PARP, and decreased levels of PARP, Bcl-2, Survivin, and cyclinD1. Moreover, Hoechst 33342 staining revealed increased cell nuclear fragmentation. Conclusion: Collectively, these results show that inhibition of YAP inhibits proliferation and induces apoptosis in HL-60 cells. Therefore, a novel treatment regime involving genetic or pharmacological inhibition of YAP could be established for acute promyelocytic leukemia.

NLS-RARα Inhibits the Effects of All-trans Retinoic Acid on NB4 Cells by Interacting with P38α MAPK.

Nuclear localization signal retinoic acid receptor alpha(NLS-RARα), which forms from the cleavage of promyelocytic leukemia-retinoic acid receptor alpha(PML-RARα) protein by neutrophil elastase(NE), possesses an important role in the occurrence and development of acute promyelocytic leukemia(APL). However, the potential mechanism underlying the effects of NLS-RARα on APL is still not entirely clear. Here, we investigated the effects of NLS-RARα on APL NB4 cells and its mechanism. We found that all-trans retinoic acid(ATRA) could promote differentiation while inhibit proliferation of APL NB4 cells via upregulating the expression of phosphorylated p38α mitogen-activated protein kinase(p-p38α MAPK). We also found that NLS-RARα could inhibit differentiation while accelerate proliferation of NB4 cells via downregulating the expression of p-p38α protein in the presence of ATRA. Furthermore, immunofluorescence and co-immunoprecipitation assays confirmed NLS-RARα interacted with p38α protein directly. Finally, application of PD169316, an inhibitor of p38α protein, suggested that recruitment p38α-combinded NLS-RARα by ATRA eventually caused activation of p38α protein. In summary, our study demonstrated that ATRA cound promote differentiation while inhibit proliferation of APL NB4 cells via activating p38α protein after recruiting p38α-combinded NLS-RARα, while NLS-RARα could inhibit the effects of ATRA in the process.