Role of Lactate Dehydrogenase as a Biomarker of Early Cardiac Remodeling: A Cross-Sectional Study.

BACKGROUND: Lactate dehydrogenase (LDH) isoenzyme assay was used widely in the past to diagnose myocardial infarction (MI). Recent studies show that lactate dehydrogenase seems to be a promising biomarker of adverse left ventricular remodeling. OBJECTIVES: Higher levels of these biomarkers were associated with lower odds for favorable reverse remodeling in patients with MI. METHODS: The study was performed on patients with the first occurrence of acute myocardial infarction (ST-elevation myocardial infarction (STEMI) or non-ST-elevation myocardial infarction (NSTEMI)), aged 34 to 80 years who underwent catheterization at the admission or during their hospital stay depending on indications. In this study, we compared peak levels of lactate dehydrogenase (LDH) and left ventricular ejection fraction (LVEF). Peak values of LDH were used from the second to the fourth day of hospitalization. Echocardiography has been done in the first 72 hours, which represents an early phase of cardiac remodeling. The ejection fraction was evaluated using the Simpson method. RESULTS: Spearman's rank test showed a negative, statistically significant correlation between LDH and ejection fraction ρ(80)=-0.543, p<0.001. Weighted least squares regression model included LDH concentration, age, and type of myocardial infarction (STEMI/NSTEMI), and the slope coefficient for the LDH level was -0.010 (95% confidence interval (CI): -0.013 to -0.006). With each unit of LDH increase, there was a decrease of 0.01% in left ventricular ejection fraction when age and type of myocardial infarction were held constant. CONCLUSION: The increased LDH level could be a new predictor for early myocardial remodeling after the first occurrence of myocardial infarction independent of age and type of myocardial infarction.

A Review of Research on the Mechanism of Tumor Regulation by N-Acetyltransferase 10.

N-acetyltransferase 10 (NAT10) is an important acetyltransferase that regulates telomerase activity and participates in DNA damage reactions, ribosomal RNA (rRNA) transcriptional activation, cell division, microtubule acetylation, and other important cellular processes. Abnormalities in the expression or distribution of NAT10 result in diseases such as Hutchinson-Gilford progeria syndrome (HGPS) and various tumors, with serious consequences. Remodelin, an inhibitor of NAT10, delays HGPS progression; many studies have been conducted on its role in tumor therapy. A major breakthrough in the study of NAT10 was the discovery of mRNA N4-acetylcytidine (ac4C) modification, which can increase mRNA stability and translation efficiency significantly. In addition, NAT10 modifies the mRNA of ac4C, which is associated with tumor development. Here, we present a review of pertinent studies focusing on NAT10, particularly its role in cancer, to provide researchers with a concise and informative summary of the current state of knowledge about this topic. The conclusions drawn from this review could provide a new direction for tumor treatment.

Remodelin delays non-small cell lung cancer progression by inhibiting NAT10 via the EMT pathway.

BACKGROUND: Lung cancer remains the foremost reason of cancer-related mortality, with invasion and metastasis profoundly influencing patient prognosis. N-acetyltransferase 10 (NAT10) catalyzes the exclusive N (4)-acetylcytidine (ac4C) modification in eukaryotic RNA. NAT10 dysregulation is linked to various diseases, yet its role in non-small cell lung cancer (NSCLC) invasion and metastasis remains unclear. Our study delves into the clinical significance and functional aspects of NAT10 in NSCLC. METHODS: We investigated NAT10's clinical relevance using The Cancer Genome Atlas (TCGA) and a group of 98 NSCLC patients. Employing WB, qRT-PCR, and IHC analyses, we assessed NAT10 expression in NSCLC tissues, bronchial epithelial cells (BECs), NSCLC cell lines, and mouse xenografts. Further, knockdown and overexpression techniques (siRNA, shRNA, and plasmid) were employed to evaluate NAT10's effects. A series of assays were carried out, including CCK-8, colony formation, wound healing, and transwell assays, to elucidate NAT10's role in proliferation, invasion, and metastasis. Additionally, we utilized lung cancer patient-derived 3D organoids, mouse xenograft models, and Remodelin (NAT10 inhibitor) to corroborate these findings. RESULTS: Our investigations revealed high NAT10 expression in NSCLC tissues, cell lines and mouse xenograft models. High NAT10 level correlated with advanced T stage, lymph node metastasis and poor overall survive. NAT10 knockdown curtailed proliferation, invasion, and migration, whereas NAT10 overexpression yielded contrary effects. Furthermore, diminished NAT10 levels correlated with increased E-cadherin level whereas decreased N-cadherin and vimentin expressions, while heightened NAT10 expression displayed contrasting results. Notably, Remodelin efficiently attenuated NSCLC proliferation, invasion, and migration by inhibiting NAT10 through the epithelial-mesenchymal transition (EMT) pathway. CONCLUSIONS: Our data underscore NAT10 as a potential therapeutic target for NSCLC, presenting avenues for targeted intervention against lung cancer through NAT10 inhibition.

NAT10-mediated mRNA N4-acetylcytidine modification of MDR1 and BCRP promotes breast cancer progression.

BACKGROUND: N-acetyltransferase 10 (NAT10) serves as a critical enzyme in mediating the N4-acetylcytidine (ac4C) that ensures RNA stability and effective translation processes. The role of NAT10 in driving the advancement of breast cancer remains uninvestigated. METHODS: We observed an increase in NAT10 expression, both at mRNA level through the analysis of the Cancer Genome Atlas (TCGA) database and at the protein level of tumor tissues from breast cancer patients. We determined that a heightened expression of NAT10 served as a predictor of an unfavorable clinical outcome. By screening the Cancer Cell Line Encyclopedia (CCLE) cell bank, this expression pattern of NAT10 was consistency found across almost all the classic breast cancer cell lines. RESULTS: Functionally, interference of NAT10 expression exerts an inhibitory effect on proliferation and invasion of breast cancer cells. By using ac4C RNA immunoprecipitation (ac4c-RIP) and acRIP-qPCR assays, we identified a reduction of ac4C enrichment within the ATP binding cassette (ABC) transporters, multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP), consequent to NAT10 suppression. Expressions of MDR1 and BCRP exhibited a positive correlation with NAT10 expression in tumor tissues, and the inhibition of NAT10 in breast cancer cells resulted in a decrease of MDR1 and BCRP expression. Therefore, the overexpressing of MDR1 and BCRP could partially rescue the adverse consequences of NAT10 depletion. In addition, we found that, remodelin, a NAT10 inhibitor, reinstated the susceptibility of capecitabine-resistant breast cancer cells to the chemotherapy, both in vitro and in vivo. CONCLUSION: The results of our study demonstrated the essential role of NAT10-mediated ac4c-modification in breast cancer progression and provide a novel strategy for overcoming chemoresistance challenges.

Targeting the NAT10/NPM1 axis abrogates PD-L1 expression and improves the response to immune checkpoint blockade therapy.

BACKGROUND: PD-1/PD-L1 play a crucial role as immune checkpoint inhibitors in various types of cancer. Although our previous study revealed that NPM1 was a novel transcriptional regulator of PD-L1 and stimulated the transcription of PD-L1, the underlying regulatory mechanism remains incompletely characterized. METHODS: Various human cancer cell lines were used to validate the role of NPM1 in regulating the transcription of PD-L1. The acetyltransferase NAT10 was identified as a facilitator of NPM1 acetylation by coimmunoprecipitation and mass spectrometry. The potential application of combined NAT10 inhibitor and anti-CTLA4 treatment was evaluated by an animal model. RESULTS: We demonstrated that NPM1 enhanced the transcription of PD-L1 in various types of cancer, and the acetylation of NPM1 played a vital role in this process. In particular, NAT10 facilitated the acetylation of NPM1, leading to enhanced transcription and increased expression of PD-L1. Moreover, our findings demonstrated that Remodelin, a compound that inhibits NAT10, effectively reduced NPM1 acetylation, leading to a subsequent decrease in PD-L1 expression. In vivo experiments indicated that Remodelin combined with anti-CTLA-4 therapy had a superior therapeutic effect compared with either treatment alone. Ultimately, we verified that the expression of NAT10 exhibited a positive correlation with the expression of PD-L1 in various types of tumors, serving as an indicator of unfavorable prognosis. CONCLUSION: This study suggests that the NAT10/NPM1 axis is a promising therapeutic target in malignant tumors.

Acetyltransferase NAT10 regulates the Wnt/ß-catenin signaling pathway to promote colorectal cancer progression via ac4C acetylation of KIF23 mRNA.

BACKGROUND: N4-acetylcytidine (ac4C) as a significant RNA modification has been reported to maintain the stability of mRNA and to regulate the translation process. However, the roles of both ac4C and its 'writer' protein N-acetyltransferase 10 (NAT10) played in the disease especially colorectal cancer (CRC) are unclear. At this point, we discover the underlying mechanism of NAT10 modulating the progression of CRC via mRNA ac4C modification. METHODS: The clinical significance of NAT10 was explored based on the TCGA and GEO data sets and the 80 CRC patients cohort of our hospital. qRT-PCR, dot blot, WB, and IHC were performed to detect the level of NAT10 and ac4C modification in CRC tissues and matched adjacent tissues. CCK-8, colony formation, transwell assay, mouse xenograft, and other in vivo and in vitro experiments were conducted to probe the biological functions of NAT10. The potential mechanisms of NAT10 in CRC were clarified by RNA-seq, RIP-seq, acRIP-seq, luciferase reporter assays, etc. RESULTS: The levels of NAT10 and ac4C modification were significantly upregulated. Also, the high expression of NAT10 had important clinical values like poor prognosis, lymph node metastasis, distant metastasis, etc. Furthermore, the in vitro experiments showed that NAT10 could inhibit apoptosis and enhance the proliferation, migration, and invasion of CRC cells and also arrest them in the G2/M phase. The in vivo experiments discovered that NAT10 could promote tumor growth and liver/lung metastasis. In terms of mechanism, NAT10 could mediate the stability of KIF23 mRNA by binding to its mRNA 3'UTR region and up-regulating its mRNA ac4c modification. And then the protein level of KIF23 was elevated to activate the Wnt/ß-catenin pathway and more ß-catenin was transported into the nucleus which led to the CRC progression. Besides, the inhibitor of NAT10, remodelin, was applied in vitro and vivo which showed an inhibitory effect on the CRC cells. CONCLUSIONS: NAT10 promotes the CRC progression through the NAT10/KIF23/GSK-3ß/ß-catenin axis and its expression is mediated by GSK-3ß which forms a feedback loop. Our findings provide a potential prognosis or therapeutic target for CRC and remodelin deserves more attention.

NAT10 promotes cell proliferation by acetylating CEP170 mRNA to enhance translation efficiency in multiple myeloma.

Multiple myeloma (MM) is still an incurable hematologic malignancy, which is eagerly to the discovery of novel therapeutic targets and methods. N-acetyltransferase 10 (NAT10) is the first reported regulator of mRNA acetylation that is activated in many cancers. However, the function of NAT10 in MM remains unclear. We found significant upregulation of NAT10 in MM patients compared to normal plasma cells, which was also highly correlated with MM poor outcome. Further enforced NAT10 expression promoted MM growth in vitro and in vivo, while knockdown of NAT10 reversed those effects. The correlation analysis of acetylated RNA immunoprecipitation sequencing (acRIP-seq) and ribosome profiling sequencing (Ribo-seq) combined with RIP-PCR tests identified centrosomal protein 170 (CEP170) as an important downstream target of NAT10. Interfering CEP170 expression in NAT10-OE cells attenuated the acceleration of cellular growth caused by elevated NAT10. Moreover, CEP170 overexpression promoted cellular proliferation and chromosomal instability (CIN) in MM. Intriguingly, remodelin, a selective NAT10 inhibitor, suppressed MM cellular growth, induced cellular apoptosis in vitro and prolonged the survival of 5TMM3VT mice in vivo. Collectively, our data indicate that NAT10 acetylates CEP1 70 mRNA to enhance CEP170 translation efficiency, which suggests that NAT10 may serve as a promising therapeutic target in MM.

Remodelin, a N-acetyltransferase 10 (NAT10) inhibitor, alters mitochondrial lipid metabolism in cancer cells.

Remodelin is a small molecule inhibitor of N-acetyltransferase 10 (NAT10), reported to reverse the effect of cancer conditions such as epithelial to mesenchymal transition, hypoxia, and drug resistance. We analysed RNA seq data of siNAT10 and found many metabolic pathways were altered, this made us perform unbiased metabolic analysis. Here we performed untargeted metabolomics in Remodelin treated cancer cells using high-performance liquid chromatography-tandem mass spectrometry. Statistical analysis revealed a total number of 138 of which 52 metabolites were significantly modified in Remodelin treated cells. Among the most significantly altered metabolites, we identified metabolites related with mitochondrial fatty acid elongation (MFAE) and mitochondrial beta-oxidation such as lauroyl-CoA, cholesterol, triglycerides, (S)-3-hydroxyhexadecanoyl-CoA, and NAD+ . Furthermore, assessment showed alteration in expression of Enoyl-CoA hydratase, short chain 1, mitochondrial (ECHS1), and Mitochondrial trans-2-enoyl-CoA reductase (MECR) genes, associated with MFAE pathway. We also found statistically significant decrease in total cholesterol and triglycerides in Remodelin treated cancer cells. Overall, our results showed that Remodelin alters mitochondrial fatty acid metabolism and lipid accumulation in cancer cells. Finally, we validated these results in NAT10 knockdown cancer cells and found that NAT10 reduction results in alteration in gene expression associated with mitochondrial fatty acid metabolism, clearly suggesting the possible role of NAT10 in maintaining mitochondrial fatty acid metabolism.

Bone Geometry Is Altered by Follistatin-Induced Muscle Growth in Young Adult Male Mice.

The development of the musculoskeletal system and its maintenance depends on the reciprocal relationship between muscle and bone. The size of skeletal muscles and the forces generated during muscle contraction are potent sources of mechanical stress on the developing skeleton, and they shape bone structure during growth. This is particularly evident in hypermuscular global myostatin (Mstn)-null mice, where larger muscles during development increase bone mass and alter bone shape. However, whether muscle hypertrophy can similarly influence the shape of bones after the embryonic and prepubertal period is unknown. To address this issue, bone structure was assessed after inducing muscle hypertrophy in the lower hindlimbs of young-adult C57BL/6J male mice by administering intramuscular injections of recombinant adeno-associated viral vectors expressing follistatin (FST), a potent antagonist of Mstn. Two FST isoforms were used: the full-length 315 amino acid isoform (FST-315) and a truncated 288 amino acid isoform (FST-288). In both FST-treated cohorts, muscle hypertrophy was observed, and the anterior crest of the tibia, adjacent to the tibialis anterior muscle, was lengthened. Hypertrophy of the muscles surrounding the tibia caused the adjacent cortical shell to recede inward toward the central axis: an event driven by bone resorption adjacent to the hypertrophic muscle. The findings reveal that inducing muscle hypertrophy in mice can confer changes in bone shape in early adulthood. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Remodelin, an inhibitor of NAT10, could suppress hypoxia-induced or constitutional expression of HIFs in cells.

Hypoxia-inducible factors (HIFs) are key mediators expressed under hypoxic condition and involved in many kinds of disease such as cancer and abnormal angiogenesis. Thus, development of their inhibitor has been extensively explored. Here, we describe a finding that Remodelin, a specific inhibitor of NAT10, could also inhibit the expression of HIFs. The presence of Remodelin could suppress the elevated level of HIF-1α protein and its nuclear translocation induced by either treatment of cobalt chloride (CoCl2) or hypoxia in dose or time-dependent way. More importantly, Remodelin could also inhibit the constitutional expression of HIF-1α and HIF-2α in VHL mutant 786-0 cells. With using of cells with depletion of NAT10 by shRNA or Crispr-Cas9 edited, we further demonstrated that inhibition of HIFs by Remodelin should need NAT10 activity. In biological analysis, the treatment of cultured HUVECs with Remodelin could inhibit in vitro cell migration and invasion and tube-formation. Our investigation implied that Remodelin could be a new potential inhibitor of HIFs for using in angiogenesis targeting therapy in either cancers or inflammatory diseases.

Targeting NAT10 Induces Apoptosis Associated With Enhancing Endoplasmic Reticulum Stress in Acute Myeloid Leukemia Cells.

N-acetyltransferase 10 (NAT10) has oncogenic properties in many tumors through its role in different cellular biological processes. NAT10 is also a potential biomarker in acute myeloid leukemia (AML); however, the mechanisms underlying NAT10's contribution to disease states and the effect of targeting NAT10 as a therapeutic target remain unclear. NAT10 was found to be highly expressed in patients with AML, and increased NAT10 expression was associated with poor outcomes. Additionally, targeting NAT10 via the shRNA knockdown and its pharmacotherapeutic inhibitor resulted in inhibition of cell proliferation, induction of cell cycle arrest in the G1 phase, and apoptosis in AML cells. Moreover, NAT10 induces cell cycle arrest by decreasing expression of CDK2, CDK4, CyclinD1, Cyclin E while simultaneously increasing the expression of p16 and p21. Targeting NAT10 induces ER stress through the increased expression of GRP78 and the cleavage of caspase 12, which are classical markers of ER stress. This triggered the Unfolded Protein Response (UPR) pathway by consequently increasing IRE1, CHOP, and PERK expression, all of which play crucial roles in the UPR pathway. Targeting NAT10 also activated the classical apoptotic pathway through the upregulation of the Bax/bak and the concurrent downregulation of Bcl-2. In summary, our data indicate that targeting NAT10 promotes ER stress, triggers the UPR pathway, and activates the Bax/Bcl-2 axis in AML cells. Our results thus indicate a novel mechanism underlying the induction of NAT10 inhibition-mediated apoptosis and reveal the potential for the therapeutic effect of a NAT10 specific inhibitor in AML.

Proclination-induced changes in the labial cortical bone thickness of lower incisors.

OBJECTIVES: We sought to objectivize the overall alveolar bone thickness changes in lower incisors after orthodontic intervention. BACKGROUND: The effect of orthodontic treatment on the cortical bone, specifically the clinical implications of proclination-induced change, have long been a matter of dispute. METHODS: Cone-beam computed tomographs of 58 patients were obtained before and after treatment and labial cortical bone thickness and overall alveolus width were measured in sagittal sections in the distance of 3, 6, 9 and 12 mm apically from the cemento-enamel junction. RESULTS: A statistically significant decrease of the cortical bone thickness in all four incisors was found at the levels 3, 6 and 9 mm (p 0.05). Moreover, no correlation was found between bone thickness change and extent of the incisor movement. CONCLUSION: Our results point to a marked cortical bone loss after proclination of lower incisors, furnishing a sound basis for caution in treatment planning due to the considerable risk of alveolar defect development, especially in patients with low initial bone thickness (Tab. 6, Fig. 2, Ref. 25).

Inhibition of N-acetyltransferase 10 using remodelin attenuates doxorubicin resistance by reversing the epithelial-mesenchymal transition in breast cancer.

Development of resistance to doxorubicin-based chemotherapy limits curative effect in breast cancer (BC). N-acetyltransferase 10 (NAT10), a nucleolar protein involved in histone acetylation, is overexpressed in several cancers. We investigated whether NAT10 is involved in doxorubicin resistance in BC and explored the potential mechanisms. Remodelin, a NAT10 inhibitor, and a NAT10 small interfering RNA (siRNA) were used to inhibit NAT10; both remodelin and the NAT10 siRNA reduced cell viability and attenuated doxorubicin resistance in four BC cell lines. Remodelin and doxorubicin synergistically reduced cell viability, though knockdown of NAT10 and remodelin did not exert a synergistic effect in doxorubicin-treated cells. Remodelin upregulated E-cadherin and downregulated vimentin, canonical markers of the epithelial-mesenchymal transition (EMT), whereas doxorubicin had the opposite effects. Moreover, both remodelin and knockdown of NAT10 reversed the doxorubicin-induced EMT. Finally, when the EMT was blocked using a siRNA targeting Twist, remodelin could not alleviate doxorubicin resistance. Collectively, these findings demonstrate that inhibition of NAT10 attenuates doxorubicin resistance by reversing the EMT in BC. This represents a novel mechanism of doxorubicin resistance in BC and indicates remodelin may have potential clinical value to increase the efficacy of doxorubicin-based chemotherapy in BC.

Inhibition of NAT10 Suppresses Melanogenesis and Melanoma Growth by Attenuating Microphthalmia-Associated Transcription Factor (MITF) Expression.

N-acetyltransferase 10 (NAT10) has been considered a target for the treatment of human diseases such as cancer and laminopathies; however, its functional role in the biology of melanocytes is questionable. Using a small molecule or small interfering RNA targeting NAT10, we examined the effect of NAT10 inhibition on melanogenesis and melanoma growth in human and mouse melanoma cells. Genetic silencing or chemical inhibition of NAT10 resulted in diminished melanin synthesis through the suppression of melanogenesis-stimulating genes such as those encoding dopachrome tautomerase (DCT) and tyrosinase in B16F10 melanoma cells. In addition, NAT10 inhibition significantly increased cell cycle arrest in S-phase, thereby suppressing the growth and proliferation of malignant melanoma cells in vitro and in vivo. These results demonstrate the potential role of NAT10 in melanogenesis and melanoma growth through the regulation of microphthalmia-associated transcription factor (MITF) expression and provide a promising strategy for the treatment of various skin diseases (melanoma) and pigmentation disorders (chloasma and freckles).