Distribution and associations of anterior lens zonules lengths in patients with cataract.

PURPOSE: To investigate the characteristics and associations of anterior lens zonules lengths in cataract patients via ultrasound biomicroscope (UBM) measurement. METHODS: Patients with age-related cataracts and high myopic cataracts who planned to undergo cataract surgery were included in the study. After routine ophthalmic examinations, the UBM was performed on both eyes to get images of the anterior lens zonules, and Image J software was used to measure the lengths of the lens zonules. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) diameter of both eyes were obtained by IOL Master 700. Univariate and multivariate regression analyses were used to assess associated factors of anterior lens zonules lengths. RESULTS: Forty-nine patients with age-related cataracts and 33 patients with high myopic cataracts were enrolled. High myopic cataract patients were younger and had longer anterior lens zonules. Multivariate regression analysis showed that anterior lens zonules lengths were associated with axial lengths (temporal location: ß = 0.036, P = 0.029; nasal location: ß = 0.034, P = 0.011; superior location: ß = 0.046, P = 0.002) and ACD (inferior location: ß = 0.305, P = 0.016) in right eyes. In left eyes, anterior lens zonules lengths were associated with axial lengths (temporal location: ß = 0.028, P = 0.017; inferior location: ß = 0.026, P = 0.016; nasal location: ß = 0.033, P < 0.001) and ACD (inferior location: ß = 0.215, P = 0.030; superior location: ß = 0.290, P = 0.011). CONCLUSIONS: High myopic cataract patients have longer anterior lens zonules. AL and ACD contributed to the lengths of anterior lens zonules. Thus, for patients with long AL and deeper ACD, lens zonules measurement was crucial. CLINICAL TRIAL REGISTRATION: www.chictr.org.cn identifier is ChiCTR2300071397.

Design, synthesis and triglyceride-lowering activity of tricyclic matrine derivatives for the intervention of non-alcoholic fatty liver disease.

Thirty new tricyclicmatrinic derivatives were successively synthesized and evaluated for their inhibitory activity on the accumulation of triglycerides (TG) in AML12 cells, using 12 N-m-trifluoromethylbenzenesulfonyl matrine (1) as the hit compound. Among the analogues, compound 7n possessing 11-trimethylbutylamine quaternary exerted the highest in vitro TG-lowering potency, as well as a good safety profile. 7n significantly attenuated the hepatic injury and steatosis, and ameliorated dyslipidemia and dysglycemia in the mice with non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet. Primary mechanism study revealed that upregulation of peroxisome proliferator-activated receptors α (PPARα)-carnitine palmitoyltransferase 1A (CPT1A) pathway mediated the efficacy of 7n. Our study provides powerful information for developing this kind of compound into a new class of anti-NAFLD candidates, and compound 7n is worthy of further investigation as an ideal lead compound.

Mechanism of ozone alleviation of malignant ascites in hepatocellular carcinoma through the inhibition of neutrophil extracellular traps.

Malignant ascites in hepatocellular carcinoma is usually a sign of advanced disease and poor prognosis and is also thought to be associated with chronic inflammation mediated by neutrophil extracellular trap (NET) networks. Although ozone, a strong oxidant, has significant antibacterial and anti-inflammatory effects, its effectiveness in treating malignant liver ascites is unclear. We first measured the levels of NETs in the peripheral blood of patients with liver cancer and healthy individuals. Next, we constructed the H22 tumor-bearing mouse model and observed the abdominal girth, body weight, survival rate, and survival time in each group; we marked the proteins associated with NETs in mouse intestinal tissues by immunofluorescence; cf-DNA and cytokines in ascites such as: tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), matrix metalloprotein 9 (MMP-9), and interferon gamma (IFN-γ) levels in ascites were measured by enzyme-linked immunosorbent assay. The expression levels of phosphorylated adenylate-activated protein kinase (P-AMPK) and scavenger receptor-A (SR-A) were detected by immunocytochemistry in the intestinal tissues of each group of mice. We further examined the expression of P-AMPK and SR-A proteins in ascites deposits by Western blotting. The results show, the plasma levels of NETs were higher in patients with hepatocellular carcinoma than in normal subjects (P < 0.01). Abdominal girth and body weight were significantly reduced in the ozone-treated group compared with the model group, while survival and survival time were dose dependently increased (both P < 0.05). NET-associated guanine histone H3 and myeloperoxidase were abundantly expressed at neutrophil aggregates in the intestinal tissues of the model mice, whereas their expression was significantly reduced in the ozone-treated group. The levels of cf-DNA, IL-6, IFN-γ, MMP-9, VEGF, and TNF-α were dose dependently increased in the ascites of H22 tumor-bearing mice in the ozone-treated group compared with the model group (all P < 0.01), while the expression of P-AMPK and SR-A proteins was increased in the ozone-treated group compared with the model group. Ozone showed significant antiperitoneal fluid production properties in H22 tumor-bearing mice, and ozone reduced peritoneal fluid production by activating AMPK and up-regulating SR-A phagocytosis damage-associated molecular patterns to reduce the production of NETs. This suggests that ozone could be used as a new drug for the treatment of malignant ascites in hepatocellular carcinoma.

KDM1A-mediated upregulation of METTL3 ameliorates Alzheimer's disease via enhancing autophagic clearance of p-Tau through m6A-dependent regulation of STUB1.

BACKGROUND: Alzheimer's disease (AD) is a severe neurodegenerative disorder that progressively destroys cognitive skills. Exploring the mechanism underlying autophagic clearance of phosphorylated tau (p-Tau) contributes to developing novel therapeutic strategies for AD. METHODS: SH-SY5Y and HT22 cells were treated with Aß1-42 to establish an in vitro model of AD. Cell viability was examined using CCK-8. TUNEL staining was applied to evaluate cell apoptosis. LC3 puncta was examined by IF staining. m6A modification level was evaluated through MeRIP. RNA pull-down and RIP assays were used for analyzing the interaction between IGF2BP1 and STUB1 transcripts. The binding of KDM1A to the promoter of METTL3 was confirmed by ChIP assays. APP/PS1 transgenic mice were used as an in vivo model of AD. Cognitive skills of mice were evaluated with the Morris water maze. Hippocampal damage and Aß deposition were detected through H&E and IHC staining. RESULTS: Dysregulated levels of autophagy, p-Tau and m6A was observed in an in vitro model of AD. Overexpression of METTL3 or STUB1 enhanced autophagy but reduced p-Tau level in Aß1-42-treated cells. METTL3 stabilized STUB1 mRNA through the m6A-IGF2BP1-dependent mechanism and naturally promoted STUB1 expression, thereby enhancing autophagic p-Tau clearance in Aß1-42-treated cells. Overexpression of KDM1A enhanced autophagy, m6A modification and autophagic p-Tau clearance in Aß1-42-treated cells. KDM1A-mediated upregulation of METTL3 promoted autophagic p-Tau clearance and ameliorated Alzheimer's disease both in vitro and in vivo. CONCLUSION: KDM1A-mediated upregulation of METTL3 enhances autophagic clearance of p-Tau through m6A-dependent regulation of STUB1, thus ameliorating Alzheimer's disease. Our study provides novel mechanistic insights into AD pathogenesis and potential drug targets for AD.

High-yield production of FK228 and new derivatives in a Burkholderia chassis.

FK228 (romidepsin) is the only natural histone deacetylases (HDACs) inhibitor approved by FDA to treat cutaneous and peripheral T-cell lymphoma. However, the limited supply and severe cardiotoxicity of FK228 underscore the importance to develop an effective synthetic biology platform for the manufacturing and fine-tuning of this drug lead. In this work, we constructed a Burkholderia chassis for the high-yield production of FK228-family (unnatural) natural products. By virtue of the optimized Burkholderia-specific recombineering system, the biosynthetic gene cluster (BGC) encoding the FK228-like skeleton thailandepsins (tdp) in Burkholderia thailandensis E264 was replaced with an attB integration site to afford the basal chassis KOGC1. The tdp BGC directly captured from E264 was hybridized with the FK228-encoding BGC (dep) using the versatile Red/ET technology. The hybrid BGC (tdp-dep) was integrated into the attB site of KOGC1, resulting in the heterologous expression of FK228. Remarkably, the titer reached 581 mg/L, which is 30-fold higher than that of native producer Chromobacterium violaceum No. 968. This success encouraged us to further engineer the NRPS modules 4 or 6 of hybrid tdp-dep BGC by domain units swapping strategy, and eight new FK228 derivatives (1-8) varying in the composition of amino acids were generated. Especially, the titers of 2 and 3 in KOGC1 were up to 985 mg/L and 453 mg/L, respectively. 2 and 3 displayed stronger cytotoxic activity than FK228. All in all, this work established a robust platform to produce FK228 and its new derivatives in sufficient quantities for anticancer drug development.

Roles of Bromodomain Extra Terminal Proteins in Metabolic Signaling and Diseases.

BET proteins, which recognize and bind to acetylated histones, play a key role in transcriptional regulation. The development of chemical BET inhibitors in 2010 greatly facilitated the study of these proteins. BETs play crucial roles in cancer, inflammation, heart failure, and fibrosis. In particular, BETs may be involved in regulating metabolic processes, such as adipogenesis and metaflammation, which are under tight transcriptional regulation. In addition, acetyl-CoA links energy metabolism with epigenetic modification through lysine acetylation, which creates docking sites for BET. Given this, it is possible that the ambient energy status may dictate metabolic gene transcription via a BET-dependent mechanism. Indeed, recent studies have reported that various BET proteins are involved in both metabolic signaling regulation and disease. Here, we discuss some of the most recent information on BET proteins and their regulation of the metabolism in both cellular and animal models. Further, we summarize data from some randomized clinical trials evaluating BET inhibitors for the treatment of metabolic diseases.

LncRNA nuclear-enriched abundant transcript 1 aggravates cerebral ischemia/reperfusion injury through activating early growth response-1/RNA binding motif protein 25 axis.

Ischemic stroke is a major global health issue. Ischemia and subsequent reperfusion results in stroke-related brain injury. Previous studies have demonstrated that nuclear-enriched abundant transcript 1 (NEATa and early growth response 1 (EGR1) are involved in ischemia reperfusion (IR) injury). In this study, we aimed to explore the roles of NEAT1/EGR1 axis as well as its downstream effector RNA binding motif protein 25 (RBM25) in cerebral IR injury. Oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion (MCAO) were used to establish in vitro and in vivo models of cerebral IR injury, respectively. According to our data, NEAT1, EGR1, and RBM25 levels were elevated in OGD/R-exposed SK-N-SH and SH-SY5Y cells and cerebral cortex of MCAO mice. NEAT1, EGR1, or RBM25 knockdown effectively reduced infarct volumes and apoptosis, and improved neurological function. Mechanistically, NEAT1 directly interacted with EGR1, which restrained WW domain containing E3 ubiquitin protein ligase 1 (WWP1)-mediated ubiquitination of EGR1 and subsequently caused EGR1 accumulation. EGR1 bound to RBM25 promoter and transcriptionally activated RBM25. Rescue experiments indicated that RBM25 overexpression abolished the therapeutic effects of NEAT1 knockdown. In conclusion, this work identified a novel NEAT1/EGR1/RBM25 axis in potentiating brain injury after IR insults, suggesting a potential therapeutic target for ischemic stroke.

LncRNA RMRP accelerates autophagy-mediated neurons apoptosis through miR-3142/TRIB3 signaling axis in alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is a major neurodegenerative disorder. The functions of lncRNA RMRP have been characterized mainly in various human cancers. However, the functional network of RMRP in AD progression remains unknown. METHODS: Human serum samples, AD transgenic (Tg) mice as well as SH-SY5Y cells were used in this study. The RNA expression patterns of RMRP, miR-3142 and TRIB3 were assessed by quantitative real-time PCR (qRT-PCR). Levels of apoptosis- or autophagy-associated biomarkers and TRIB3 level were evaluated using immunohistochemistry (IHC), western blotting or immunofluorescence assays, respectively. Bioinformatics methods and luciferase assays were used to predict and validate the interactions among RMRP, miR-3142, and TRIB3. Flow cytometry, TUNEL staining and EdU assays were used to examine the apoptosis and proliferation of neurons, respectively. RESULTS: The elevated RMRP and TRIB3 expressions and activation of autophagy were observed in AD. Knockdown of RMRP restrained neuronal apoptosis and autophagy activation in vitro and in vivo. Interestingly, TRIB3 overexpression reversed the biological effects of RMRP silencing on Aß1-42-induced cell apoptosis and autophagy. Further mechanistic analysis showed RMRP acted as a sponge of miR-3142 to elevate TRIB3 level. CONCLUSION: These data illustrated that knockdown of RMRP inhibited autophagy and apoptosis via regulating miR-3142/TRIB3 axis in AD, suggesting that inhibition of RMRP maybe a therapeutic strategy for AD.

PlGF Reduction Compromises Angiogenesis in Diabetic Foot Disease Through Macrophages.

Diabetic foot disease (DFD) is a common and serious complication for diabetes and is characterized with impaired angiogenesis. In addition to the well-defined role of vascular endothelial growth factor (VEGF) -A and its defect in the pathogenesis of DFD, another VEGF family member, placental growth factor (PlGF), was also recently found to alter expression pattern in the DFD patients with undetermined mechanisms. This question was thus addressed in the current study. We detected attenuated PlGF upregulation in a mouse DFD model. In addition, the major cell types at the wound to express the unique PlGF receptor, VEGF receptor 1 (VEGFR1), were macrophages and endothelial cells. To assess how PlGF regulates DFD-associated angiogenesis, we injected recombinant PlGF and depleted VEGF1R specifically in macrophages by local injection of an adeno-associated virus (AAV) carrying siRNA for VEGFR1 under a macrophage-specific CD68 promoter. We found that the angiogenesis and recovery of the DFD were both improved by PlGF injection. The PlGF-induced improvement in angiogenesis and the recovery of skin injury were largely attenuated by macrophage-specific depletion of VEGF1R, likely resulting from reduced macrophage number and reduced M2 polarization. Together, our data suggest that reduced PlGF compromises angiogenesis in DFD at least partially through macrophages.

TRIB3 facilitates glioblastoma progression via restraining autophagy.

The pseudokinase Tribble 3 (TRIB3) is known as a regulator in cellular responses to a variety of stresses, such as glucose insufficiency and endoplasmic reticulum (ER) stress. TRIB3 is upregulated in various cancer tissues and is closely connected to the poor prognosis of patients. However, the underlying regulation and function of TRIB3 in glioblastoma (GBM) is still largely unknown. In this study, the upregulation of TRIB3 was confirmed both in primary specimens from GBM patients and in vitro with GBM cell lines. Overexpression of specific TRIB3 transcripts promoted cell growth and migration in vitro, while knockdown of TRIB3 expression exerted a repressive effect on these cellular processes. The growth-promoting effect of TRIB3 was also demonstrated in a xenograft mouse model. Mechanistic studies further revealed that TRIB3 was able to suppress autophagic flux and that this suppression was responsible for TRIB3 silencing-induced proliferation and migration of GBM cells. These findings indicate that the suppression of autophagic flux by TRIB3 drives the invasion and proliferation of GBM cells, thus suggesting that TRIB3 is a potential novel therapeutic target for the treatment of glioma.

BET proteins inhibitor JQ-1 impaired the extinction of remote auditory fear memory: An effect mediated by insulin like growth factor 2.

Fear extinction is an important preclinical model for behavior therapy in human anxiety disorders, such as post-traumatic stress disorder (PTSD). Histone acetylation is involved in the extinction of fear memory. As the "readers" of histone acetylation markers, the role of the bromodomain and extraterminal domain (BET) proteins in fear extinction is still unclear. In the present study, we found that suppression of BET proteins using small molecule JQ-1 had no effects on the acquisition of auditory fear or on the extinction of recent auditory fear, but it impaired the extinction of remote auditory fear. We found that insulin like growth factor 2 (IGF-2) mRNA and protein were up-regulated in the anterior cingulate cortex (ACC) after the extinction training of remote fear memory, and that this effect was inhibited by JQ-1 administration. Further, the local delivery of IGF-2 protein to the ACC region rescued the impaired extinction of remote memory caused by JQ-1 administration, which suggesting IGF-2 mediates the effects of JQ-1 on remote memory extinction. Gene expression profiling analysis demonstrated that JQ-1 treatment inhibited the up-regulated expression of a key set of neuroplasticity-related genes following remote memory extinction. Together, these findings establish BET proteins as epigenetic mediator for the extinction of remote fear memory. In particular, the findings of this study imply that as a prospective preclinical cancer drug, JQ-1 (or other BET bromodomain inhibitors) should be modified to prevent it from crossing the blood brain barrier and causing neurological side effects.

Bromodomain-containing protein 4 contributes to renal fibrosis through the induction of epithelial-mesenchymal transition.

Fibrosis is a common pathology in renal disease. Hypertensive nephropathy (HN) is one of the most common secondary nephropathies that often progresses to severe renal fibrosis with limited treatment options beyond hypertension control. Bromodomain-containing protein 4 (Brd4) was recently recognized as a target in signaling pathways that underlie the pathologies of inflammatory diseases and tumors. A recently developed inhibitor of Brd4, JQ1, has been shown to exert antifibrotic effects and is being clinically explored as an anti-inflammatory and antitumor drug. Here, using human kidney biopsies and Angiotensin II-induced mouse fibrotic kidney samples, we show that Brd4 was upregulated in renal tissue from HN patients and hypertensive mouse models. In mice, JQ1 alleviated Angiotensin II-induced kidney fibrosis and blocked epithelial-mesenchymal transition (EMT) by altering the expression of EMT-related proteins. Using an in vitro model of HK2 cells exposed to Angiotensin II, we also demonstrated that JQ1 suppressed the protein expression of fibrotic genes in these cells. These results further implicate Brd4 in the fibrotic response in HN and reveal that Brd4 is a potential antifibrotic target. BET inhibitors are currently being investigated in clinical trials as antitumor agents and show potent pharmacological effects. Our findings suggest that BET inhibitors may also be potential translational therapies for HN.

The mevalonate coordinates energy input and cell proliferation.

The mevalonate pathway is known for the synthesis of cholesterol, but recent studies have reported that it also controls Hippo signaling, which is critical for the regulation of organ size and tumorigenesis. Here, we discover that the suppression of the mevalonate pathway inhibits the growth and proliferation of colon cancer cell lines. The results of transcriptomic and proteomic assays suggested that the mevalonate pathway controls multiple signaling pathways relevant to cell proliferation, and the results were further confirmed using western blot, PCR, and immunofluorescence assays. As cell proliferation is an energy-consuming process, we postulate that the mevalonate pathway may also control nutrient uptake to coordinate the processes of energy supply and cell proliferation. Here, we found that lovastatin, a mevalonate pathway inhibitor, suppresses glucose and amino acid uptake and lactate acid production. More importantly, mevalonic acid itself is sufficient to promote glucose uptake by colon cancer cells. In addition, we found that colon cancer tissues displayed a higher expression of mevalonate pathway enzymes, which may promote cell growth and stimulate energy uptake. Together, our findings establish the mevalonate pathway as a critical regulator in coordinating energy input and cell proliferation.

Carbapenem susceptibilities of Gram-negative pathogens in intra-abdominal and urinary tract infections: updated report of SMART 2015 in China.

BACKGROUND: To evaluate the susceptibility rates of aerobic and facultative Gram-negative bacterial isolates from Chinese intra-abdominal infections (IAI) and urinary tract infections (UTI) focusing on carbapenems and comparing their effectiveness between 2014 and 2015. METHODS: A total of 2318 strains in 2015 (1483 from IAI and 835 from UTI) and 2374 strains in 2014 (1438 from IAI and 936 from UTI) were included in the analysis. Antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards. Hospital acquired (HA) IAI and UTI were defined as isolates sampled > 48 h and community acquired (CA) as isolates sampled < 48 h after admission. RESULTS: The main species derived from IAI and UTI in 2015 were Escherichia coli (50.86%) and Klebsiella pneumoniae (19.20%). Susceptibilities of Escherichia coli IAI and UTI strains to imipenem (IPM) and ertapenem (ETP) were > 90% in 2014 and 2015, while the susceptibilities to IPM and ETP of Klebsiella pneumoniae IAI strains were >  80% in 2014 but dropped to ≤80% in 2015 for UTI strains. Susceptibilities of IAI Enterobacteriaceae strains to IPM and ETP in 2015 were lowest in the colon and abscesses, and Enterobacteriaceae susceptibilities of UTI and IAI isolates to IPM and ETP were lowest in medical, pediatric and surgery intensive care units (ICUs) in 2015. CONCLUSIONS: IPM and ETP were effective in vitro against Enterobacteriaceae isolated from IAIs and UTIs in 2014 and 2015, but susceptibility to carbapenems in UTIs markedly decreased in 2015.

Serum long noncoding RNA urothelial carcinoma-associated 1: A novel biomarker for diagnosis and prognosis of hepatocellular carcinoma.

Objective Long noncoding RNAs (lncRNAs) offer great potential as cancer biomarkers. This study was performed to assess the applicability of serum lncRNA urothelial carcinoma-associated 1 (UCA1) as a diagnostic and/or prognostic biomarker for hepatocellular carcinoma (HCC). Methods We examined UCA1 expression in serum samples from 105 patients with HCC, 105 patients with benign liver disease (BLD), and 105 healthy volunteers using reverse-transcription polymerase chain reaction and analyzed the relationship between serum UCA1 and clinicopathological parameters of HCC as well as survival. Results Expression of serum UCA1 was significantly higher in patients with HCC and allowed for discrimination of HCC from BLD and healthy controls. High expression of serum UCA1 was significantly associated with a high tumor grade, large tumor size, positive vascular invasion, and advanced TNM stage. Multivariate analysis revealed that a high serum UCA1 level was an independent unfavorable prognostic factor for HCC. Conclusions Our results confirm the upregulation of serum UCA1 expression in HCC and indicate its clinical value as a noninvasive biomarker for HCC screening and prognostic prediction.

BET bromodomain is a novel regulator of TAZ and its activity.

Transcriptional coactivator with PDZ-binding motif (TAZ) is a key transcriptional mediator of Hippo signaling that has been recently reported to mediate Wnt-activated transcription and serve as a component to suppress canonical Wnt/ß-catenin activity. The Bromodomain and Extra-terminal domain (BET) family of proteins can recognize the acetylated lysine chain on histones and plays a critical role in transcriptional regulation. However, the mechanisms underlying transcriptional repression by the BET bromodomain are poorly understood. Here, we found that BET bromodomain inhibition upregulated TAZ protein and its transcriptional output, independent of its well-established role as a mediator of Hippo and Wnt signaling. Additionally, JQ1, a synthetic BET inhibitor, suppressed Wnt/ß-catenin activity by upregulating TAZ. Although JQ1 upregulated TAZ, which is known to promote cell proliferation, it drastically suppressed the growth of colon cancer cells by inducing cell cycle arrest. Collectively, our study identified an unexpected transcriptional repression function of the BET bromodomain and a novel mechanism for TAZ upregulation.

[Y-27632 reduces the MMP2 and MMP9 expression in endothelial cell via inhibition of ROCK signal pathway].

OBJECTIVE: To explore the effect of ROCK inhibitor Y-27632 on the matrix metalloproteinase 2 and 9 (MMP2 and MMP9) gene expression and activity in tumor necrosis factor α (TNF-α)-treated human umbilical vein endothelial cell (HUVEC).
 METHODS: HHUVEC was divided into 3 groups, a control group, a TNF-α group, and a TNF-α plus Y-27632 group. The expressions of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), MMP2 and MMP9 were examined by real-time PCR. The MMP2/9 activity was measured by gelatin zymography.
 RESULTS: Compared to the control group, the mRNA expressions of ICAM-1, VCAM-1, MMP2 and MMP9 were increased TNF-α-treated cells, which were suppressed by ROCK inhibitor (P<0.01). The MMP2/9 activity was elevated in TNF-α-treated cells, which was reversed by ROCK inhibitor (P<0.05).
 CONCLUSION: ROCK inhibitor can suppress TNF-α-induced inflammation in endothelial cells through down-regulation of MMP2/9.

Overexpression of PAD4 suppresses drug resistance of NSCLC cell lines to gefitinib through inhibiting Elk1-mediated epithelial-mesenchymal transition.

It is reported that epithelial-to-mesenchymal transition (EMT) could induce resistance in tumor cells, and knockdown of peptidylarginine deiminase IV (PAD4) induces the activity of EMT. However, the role of PAD4 in gefitinib­acquired resistance in non-small cell lung cancer (NSCLC) remains unclear. In this study, we aimed to investigate the role of PAD4 in the resistance of NSCLC to gefitinib. The cells resistant to gefitinib were established in accordance with the literature, and were derived from NSCLC cell lines HCC827 and H1650. Real-time quantitative PCR and western blot results showed that PAD4 was obviously downregulated in the cells resistant to gefitinib. Overexpression of PAD4 distinctly inhibited gefitinib resistance, whereas PAD4 downregulation had the opposite effect. Further data indicated that PAD4 upregulation could restrain EMT activity via controlling the expression of ETS-domain containing protein (Elk1). Conversely, inhibition of PAD4 showed the reverse function compared with PAD4 upregulation. Above all, our study showed that overexpression of PAD4 constrains the activity of EMT via suppressing Elk1 expression, and inhibits resistance of NSCLC to gefitinib.