Peptide Inhibitor Targeting the Extraterminal Domain in BRD4 Potently Suppresses Breast Cancer Both In Vitro and In Vivo.

BRD4 is associated with a variety of human diseases, including breast cancer. The crucial roles of amino-terminal bromodomains (BDs) of BRD4 in binding with acetylated histones to regulate oncogene expression make them promising drug targets. However, adverse events impede the development of the BD inhibitors. BRD4 adopts an extraterminal (ET) domain, which recruits proteins to drive oncogene expression. We discovered a peptide inhibitor PiET targeting the ET domain to disrupt BRD4/JMJD6 interaction, a protein complex critical in oncogene expression and breast cancer. The cell-permeable form of PiET, TAT-PiET, and PROTAC-modified TAT-PiET, TAT-PiET-PROTAC, potently inhibits the expression of BRD4/JMJD6 target genes and breast cancer cell growth. Combination therapy with TAT-PiET/TAT-PiET-PROTAC and JQ1, iJMJD6, or Fulvestrant exhibits synergistic effects. TAT-PiET or TAT-PiET-PROTAC treatment overcomes endocrine therapy resistance in ERα-positive breast cancer cells. Taken together, we demonstrated that targeting the ET domain is effective in suppressing breast cancer, providing a therapeutic avenue in the clinic.

Oxalisxishuiensis (Oxalidaceae), a new species from Danxia landforms in Guizhou, China.

Oxalisxishuiensis, a new species of Oxalidaceae from Danxia landforms of Xishui County, Guizhou, China, is described and illustrated. It is morphologically similar to O.wulingensis by the two lateral leaflets arranged at about 180° angle and oblong pink petals with lilac veins, but clearly differs from the latter by leaflets almost as long as wide, obliquely obcordate lateral leaflets, shorter peduncles, longer capsule (1.2-1.5 cm vs. 0.5-0.7 cm) and alveolate seeds.

Anti-pancreatic cancer activity of cassane diterpenoids isolated from the seeds of Caesalpinia sappan mediated by autophagy activation via ROS/AMPK/mTORC1 pathway.

Three undescribed cassane diterpenoids, caesalpanins D-F (1-3), and seven known ones were isolated from the seeds of Caesalpinia sappan. Structures and absolute configurations of 1-3 were elucidated based on the extensive spectroscopic analysis, single-crystal X-ray diffraction analysis, and ECD calculations. Structurally, compound 1 was the first example of 18-norcassane diterpenoid and 2 was a rare 20-norcassane diterpenoid having an unusual five-membered oxygen bridge between C-10/C-18. The anti-proliferative activity of 1, 3, and 4-10 against PANC-1 cells (pancreatic ductal adenocarcinoma cell line) was evaluated, and phanginin H (4) was found to exhibit anti-cancer activity with IC50 value of 18.13 ± 0.63 µM. Compound 4 inhibited PANC-1 cell growth by arresting the cell cycle at G2/M phase via regulation of cyclin-dependent kinases, and the self-renewal and metastasis of PANC-1 cells by suppressing cancer cell stemness. Furthermore, compound 4 induced ROS generation and subsequently activated autophagy, which is demonstrated by the formation of autophagic vacuoles and dynamic change of autophagic flux. The induced ROS accumulation resulted in AMPK activation and subsequently regulation of mTORC1 activity and ULK phosphorylation, indicating that 4 triggered autophagy through ROS/AMPK/mTORC1 pathway. These findings suggested that 4 might potentially be an autophagy inducer for the therapy of pancreatic cancer.

Growth-regulated co-occupancy of Mediator and Lsm3 at intronic ribosomal protein genes.

Mediator is a well-known transcriptional co-regulator and serves as an adaptor between gene-specific regulatory proteins and RNA polymerase II. Studies on the chromatin-bound form of Mediator revealed interactions with additional protein complexes involved in various transcription-related processes, such as the Lsm2-8 complex that is part of the spliceosomal U6 small nuclear ribonucleoprotein complex. Here, we employ Chromatin Immunoprecipitation sequencing (ChIP-seq) of chromatin associated with the Lsm3 protein and the Med1 or Med15 Mediator subunits. We identify 86 genes co-occupied by both Lsm3 and Mediator, of which 73 were intron-containing ribosomal protein genes. In logarithmically growing cells, Mediator primarily binds to their promoter regions but also shows a second, less pronounced occupancy at their 3'-exons. During the late exponential phase, we observe a near-complete transition of Mediator from these promoters to a position in their 3'-ends, overlapping the Lsm3 binding sites ∼250 bp downstream of their last intron-exon boundaries. Using an unbiased RNA sequencing approach, we show that transition of Mediator from promoters to the last exon of these genes correlates to reduction of both their messenger RNA levels and splicing ratios, indicating that the Mediator and Lsm complexes cooperate to control growth-regulated expression of intron-containing ribosomal protein genes at the levels of transcription and splicing.

Genetic variants, haplotype determination, and function of novel alleles of CYP2B6 in a Han Chinese population.

Amino acid variants in protein may result in deleterious effects on enzymatic activity. In this study we investigate the DNA variants on activity of CYP2B6 gene in a Chinese Han population for potential use in precision medicine. All exons in CYP2B6 gene from 1483 Chinese Han adults (Zhejiang province) were sequenced using Sanger sequencing. The effects of nonsynonymous variants on recombinant protein catalytic activity were investigated in vitro with Sf12 system. The haplotype of novel nonsynonymous variants with other single nucleotide variants in the same allele was determined using Nanopore sequencing. Of 38 alleles listed on the Pharmacogene Variation Consortium, we detected 7 previously reported alleles and 18 novel variants, of which 11 nonsynonymous variants showed lower catalytic activity (0.00-0.60) on bupropion compared to CYP2B6*1. Further, these 11 novel star-alleles (CYP2B6*39-49) were assigned by the Pharmacogene Variation Consortium, which may be valuable for pharmacogenetic research and personalized medicine.

Promiscuous G-protein activation by the calcium-sensing receptor.

The human calcium-sensing receptor (CaSR) detects fluctuations in the extracellular Ca2+ concentration and maintains Ca2+ homeostasis1,2. It also mediates diverse cellular processes not associated with Ca2+ balance3-5. The functional pleiotropy of CaSR arises in part from its ability to signal through several G-protein subtypes6. We determined structures of CaSR in complex with G proteins from three different subfamilies: Gq, Gi and Gs. We found that the homodimeric CaSR of each complex couples to a single G protein through a common mode. This involves the C-terminal helix of each Gα subunit binding to a shallow pocket that is formed in one CaSR subunit by all three intracellular loops (ICL1-ICL3), an extended transmembrane helix 3 and an ordered C-terminal region. G-protein binding expands the transmembrane dimer interface, which is further stabilized by phospholipid. The restraint imposed by the receptor dimer, in combination with ICL2, enables G-protein activation by facilitating conformational transition of Gα. We identified a single Gα residue that determines Gq and Gs versus Gi selectivity. The length and flexibility of ICL2 allows CaSR to bind all three Gα subtypes, thereby conferring capacity for promiscuous G-protein coupling.

[Potential Ecological Risk Characteristics and Source Apportionment of Heavy Metals in Farmland Soils around Typical Factories in Hunan Province Based on Monte-Carlo Simulation].

In order to explore the pollution characteristics， ecological risks， and pollution sources of heavy metals in farmland soils around typical factories in Hunan Province， the content characteristics of eight heavy metals in farmland soils around fluoride factories， leather factories， and plating plants were analyzed. The geo-accumulation index and potential ecological risk index were used to evaluate the pollution and environmental risk of heavy metals. The correlation analysis， hierarchical cluster analysis， and principal component analysis were used to analyze the sources of heavy metals. The Monte-Carlo model was used to evaluate the probability risk of regional ecological risk. The results showed that the main pollution elements in the soil were Cd and Zn， and their mean values were 4.46 and 2.73 times the background values， respectively. Zn was at a mild pollution level in the soil of the three typical factories， and Cd was at a moderate pollution level in the whole fluoride factory. The pollution sources of heavy metals in the typical factories were mainly natural sources， industrial activity sources （industrial waste discharge， mineral mining， and smelting activities）， traffic sources， etc. The results of potential ecological risk assessment showed that the ecological risk of the fluoride factory was at a high risk level， and the ecological risk of the leather factory and plating plants was at a high risk level. Cd was the main contributing element. The results of Monte-Carlo probabilistic ecological risk assessment reduced the uncertainty of deterministic assessment， which could provide scientific basis for accurate risk management and control in the regions.

Nuclear AGO2 promotes myocardial remodeling by activating ANKRD1 transcription in failing hearts.

Heart failure (HF) is manifested by transcriptional and posttranscriptional reprogramming of critical genes. Multiple studies have revealed that microRNAs could translocate into subcellular organelles such as the nucleus to modify gene expression. However, the functional property of subcellular Argonaute2 (AGO2), the core member of the microRNA machinery, has remained elusive in HF. AGO2 was found to be localized in both the cytoplasm and nucleus of cardiomyocytes, and robustly increased in the failing hearts of patients and animal models. We demonstrated that nuclear AGO2 rather than cytosolic AGO2 overexpression by recombinant adeno-associated virus (serotype 9) with cardiomyocyte-specific troponin T promoter exacerbated the cardiac dysfunction in transverse aortic constriction (TAC)-operated mice. Mechanistically, nuclear AGO2 activates the transcription of ANKRD1, encoding ankyrin repeat domain-containing protein 1 (ANKRD1), which also has a dual function in the cytoplasm as part of the I-band of the sarcomere and in the nucleus as a transcriptional cofactor. Overexpression of nuclear ANKRD1 recaptured some key features of cardiac remodeling by inducing pathological MYH7 activation, whereas cytosolic ANKRD1 seemed cardioprotective. For clinical practice, we found ivermectin, an antiparasite drug, and ANPep, an ANKRD1 nuclear location signal mimetic peptide, were able to prevent ANKRD1 nuclear import, resulting in the improvement of cardiac performance in TAC-induced HF.

Accumulation of antitumor polyketides by fermentation of Rubus delavayi Franch. with Clonostachys rogersoniana.

The aim of this work is to explore the effects of herbal medicine on secondary metabolites of microorganisms during fermentation. Clonostachys rogersoniana was found to metabolize only small amounts of polyketide glycosides rogerson B and C on fresh potatoes, but after replacing the medium to the medicinal plant Rubus delavayi Franch., the type and content of the metabolized polyketones showed significant changes. The sugars and glycosides in R. delavayi are probably responsible for the changes in secondary metabolites. Six polyketide glycosides including a new metabolite, rogerson F, and two potential antitumor compounds, TMC-151C and TMC-151D, were isolated from the extract of R. delavayi fermented by C. rogersoniana. In addition, 13C labeling experiments were used to trace the biosynthesis process of these compounds. TMC-151C and TMC-151D showed significant cytotoxic activity against PANC-1, K562 and HCT116 cancer cells but had no obvious cytotoxic activity against BEAS-2B human normal lung epithelial cells. The yields of TMC-151C and TMC-151D reached 14.37 ± 1.52 g/kg and 1.98 ± 0.43 g/kg, respectively, after fermentation at 28 °C for 30 days. This is the first study to confirm that herbal medicine can induce microbes to metabolize active compounds. And the technology of fermenting medicinal materials can bring more economic value to medicinal plants.

LncRNA LUESCC promotes esophageal squamous cell carcinoma by targeting the miR-6785-5p/NRSN2 axis.

Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent gastrointestinal malignancies with high mortality worldwide. Emerging evidence indicates that long noncoding RNAs (lncRNAs) are involved in human cancers, including ESCC. However, the detailed mechanisms of lncRNAs in the regulation of ESCC progression remain incompletely understood. LUESCC was upregulated in ESCC tissues compared with adjacent normal tissues, which was associated with gender, deep invasion, lymph node metastasis, and poor prognosis of ESCC patients. LUESCC was mainly localized in the cytoplasm of ESCC cells. Knockdown of LUESCC inhibited cell proliferation, colony formation, migration, and invasion in vitro and suppressed tumor growth in vivo. Mechanistic investigation indicated that LUESCC functions as a ceRNA by sponging miR-6785-5p to enhance NRSN2 expression, which is critical for the malignant behaviors of ESCC. Furthermore, ASO targeting LUESCC substantially suppressed ESCC both in vitro and in vivo. Collectively, these data demonstrate that LUESCC may exerts its oncogenic role by sponging miR-6785-5p to promote NRSN2 expression in ESCC, providing a potential diagnostic marker and therapeutic target for ESCC patients.

CircHIPK3 regulates fatty acid metabolism through miR-637/FASN axis to promote esophageal squamous cell carcinoma.

The oncogenic role of circRNA in cancers including esophageal cancer (EC) has been well studied. However, whether and how circRNAs are involved in cancer cell metabolic processes remains largely unknown. Here, we reported that circRNA, circHIPK3, is highly expressed in ESCC cell lines and tissues. Knockdown of circHIPK3 significantly restrained cell proliferation, colony formation, migration, and invasion in vitro and inhibited tumor growth in vivo. Mechanistically, circHIPK3 was found to act as a ceRNA by sponging miR-637 to regulate FASN expression and fatty acid metabolism in ESCC cells. Anti-sense oligonucleotide (ASO) targeting circHIPK3 substantially inhibited ESCC both in vitro and in vivo. Therefore, these results uncover a modulatory axis constituting of circHIPK3/miR-637/FASN may be a potential biomarker and therapeutic target for ESCC in the clinic.

Quercetin Alleviates Lipopolysaccharide-Induced Cardiac Inflammation via Inhibiting Autophagy and Programmed Cell Death.

Objective: The aim of this study is to explore the potential modulatory role of quercetin against Endotoxin or lipopolysaccharide (LPS) induced septic cardiac dysfunction. Methods: Specific pathogen-free chicken embryos ( n = 120) were allocated untreated control, phosphate buffer solution (PBS) vehicle, PBS with ethanol vehicle, LPS (500 ng/egg), LPS with quercetin treatment (10, 20, or 40 nmol/egg, respectively), Quercetin groups (10, 20, or 40 nmol/egg). Fifteen-day-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity. At embryonic day 19, the hearts of the embryos were collected for histopathological examination, RNA extraction, real-time polymerase chain reaction, immunohistochemical investigations, and Western blotting. Results: They demonstrated that the heart presented inflammatory responses after LPS induction. The LPS-induced higher mRNA expressions of inflammation-related factors (TLR4, TNFα, MYD88, NF-κB1, IFNγ, IL-1ß, IL-8, IL-6, IL-10, p38, MMP3, and MMP9) were blocked by quercetin with three dosages. Quercetin significantly decreased immunopositivity to TLR4 and MMP9 in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of TLR4, IFNγ, MMP3, and MMP9 when compared with the LPS group. Quercetin treatment prevented LPS-induced increase in the mRNA expression of Claudin 1 and ZO-1, and significantly decreased protein expression of claudin 1 when compared with the LPS group. Quercetin significantly downregulated autophagy-related gene expressions (PPARα, SGLT1, APOA4, AMPKα1, AMPKα2, ATG5, ATG7, Beclin-1, and LC3B) and programmed cell death (Fas, Bcl-2, CASP1, CASP12, CASP3, and RIPK1) after LPS induction. Quercetin significantly decreased immunopositivity to APOA4, AMPKα2, and LC3-II/LC3-I in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of AMPKα1, LC3-I, and LC3-II. Quercetin significantly decreased the protein expression to CASP1 and CASP3 by immunohistochemical investigation or Western blotting in treatment group when compared with LPS group. Conclusion: Quercetin alleviates cardiac inflammation induced by LPS through modulating autophagy, programmed cell death, and myocardiocytes permeability.

CDK6 inhibits de novo lipogenesis in white adipose tissues but not in the liver.

Increased de novo lipogenesis (DNL) in white adipose tissue is associated with insulin sensitivity. Under both Normal-Chow-Diet and High-Fat-Diet, mice expressing a kinase inactive Cyclin-dependent kinase 6 (Cdk6) allele (K43M) display an increase in DNL in visceral white adipose tissues (VAT) as compared to wild type mice (WT), accompanied by markedly increased lipogenic transcriptional factor Carbohydrate-responsive element-binding proteins (CHREBP) and lipogenic enzymes in VAT but not in the liver. Treatment of WT mice under HFD with a CDK6 inhibitor recapitulates the phenotypes observed in K43M mice. Mechanistically, CDK6 phosphorylates AMP-activated protein kinase, leading to phosphorylation and inactivation of acetyl-CoA carboxylase, a key enzyme in DNL. CDK6 also phosphorylates CHREBP thus preventing its entry into the nucleus. Ablation of runt related transcription factor 1 in K43M mature adipocytes reverses most of the phenotypes observed in K43M mice. These results demonstrate a role of CDK6 in DNL and a strategy to alleviate metabolic syndromes.

The complete chloroplast genome of Chrysoglossum ornatum (Epidendroideae, Orchidaceae) and its phylogenetic analysis.

Chrysoglossum ornatum Blume, the type species of Chrysoglossum Blume, belongs to the tribe Collabieae of the subfamily Epidendroideae of Orchidaceae. In this study, we sequenced, assembled, and analyzed the complete chloroplast genome of C. ornatum. The result showed that the complete chloroplast genome of C. ornatum was 158,175 bp in size, consisting of a large single-copy (LSC) region of 87,235 bp, a small single-copy (SSC) region of 18,384 bp, and a pair of inverted repeats (IRs) of 26,278 bp. The chloroplast genome encoded 113 unique genes, comprising 80 protein-coding genes, 29 tRNA genes, and four rRNA genes. Phylogenetic analysis inferred from the complete chloroplast genome indicated that Chrysoglossum was closely related to Collabium Blume. This study provides genomic resources helpful for further phylogenetic and biodiversity research on Chrysoglossum.

Inhibitory effects of the main metabolites of Apatinib on CYP450 isozymes in human and rat liver microsomes.

PURPOSE: The inhibitory effect of Apatinib on cytochrome P450 (CYP450) enzymes has been studied. However, it is unknown whether the inhibition is related to the major metabolites, M1-1, M1-2 and M1-6. METHODS: A 5-in-1 cocktail system composed of CYP2B6/Cyp2b1, CYP2C9/Cyp2c11, CYP2E1/Cyp2e1, CYP2D6/Cyp2d1 and CYP3A/Cyp3a2 was used in this study. Firstly, the effects of APA and its main metabolites on the activities of HLMs, RLMs and recombinant isoforms were examined. The reaction mixture included HLMs, RLMs or recombinant isoforms (CYP3A4.1, CYP2D6.1, CYP2D6.10 or CYP2C9.1), analyte (APA, M1-1, M1-2 or M1-6), probe substrates. The reactions were pre-incubated for 5 min at 37 °C, followed by the addition of NAPDH to initiate the reactions, which continued for 40 min. Secondly, IC50 experiments were conducted to determine if the inhibitions were reversible. The reaction mixture of the "+ NADPH Group" included HLMs or RLMs, 0 to 100 of µM M1-1 or M1-2, probe substrates. The reactions were pre-incubated for 5 min at 37 °C, and then NAPDH was added to initiate reactions, which proceeded for 40 min. The reaction mixture of the "- NADPH Group" included HLMs or RLMs, probe substrates, NAPDH. The reactions were pre-incubated for 30 min at 37 °C, and then 0 to 100 µM of M1-1 or M1-2 was added to initiate the reactions, which proceeded for 40 min. Finally, the reversible inhibition of M1-1 and M1-2 on isozymes was determined. The reaction mixture included HLMs or RLMs, 0 to 10 µM of M1-1 or M1-2, probe substrates with concentrations ranging from 0.25Km to 2Km. RESULTS: Under the influence of M1-6, the activity of CYP2B6, 2C9, 2E1 and 3A4/5 was increased to 193.92%, 210.82%, 235.67% and 380.12% respectively; the activity of CYP2D6 was reduced to 92.61%. The inhibitory effects of M1-1 on CYP3A4/5 in HLMs and on Cyp2d1 in RLMs, as well as the effect of M1-2 on CYP3A in HLMs, were determined to be noncompetitive inhibition, with the Ki values equal to 1.340 µM, 1.151 µM and 1.829 µM, respectively. The inhibitory effect of M1-1 on CYP2B6 and CYP2D6 in HLMs, as well as the effect of M1-2 on CYP2C9 and CYP2D6 in HLMs, were determined to be competitive inhibition, with the Ki values equal to 12.280 µM, 2.046 µM, 0.560 µM and 4.377 µM, respectively. The inhibitory effects of M1-1 on CYP2C9 in HLMs and M1-2 on Cyp2d1 in RLMs were determined to be mixed-type, with the Ki values equal to 0.998 µM and 0.884 µM. The parameters could not be obtained due to the atypical kinetics of CYP2E1 in HLMs under the impact of M1-2. CONCLUSIONS: M1-1 and M1-2 exhibited inhibition for several CYP450 isozymes, especially CYP2B6, 2C9, 2D6 and 3A4/5. This observation may uncover potential drug-drug interactions and provide valuable insights for the clinical application of APA.

A modified nucleoside O6-methyl-2'-deoxyguanosine-5'-triphosphate exhibits anti-glioblastoma activity in a caspase-independent manner.

Resistance to temozolomide (TMZ), the frontline chemotherapeutic agent for glioblastoma (GBM), has emerged as a formidable obstacle, underscoring the imperative to identify alternative therapeutic strategies to improve patient outcomes. In this study, we comprehensively evaluated a novel agent, O6-methyl-2'-deoxyguanosine-5'-triphosphate (O6-methyl-dGTP) for its anti-GBM activity both in vitro and in vivo. Notably, O6-methyl-dGTP exhibited pronounced cytotoxicity against GBM cells, including those resistant to TMZ and overexpressing O6-methylguanine-DNA methyltransferase (MGMT). Mechanistic investigations revealed that O6-methyl-dGTP could be incorporated into genomic DNA, disrupting nucleotide pools balance, and inducing replication stress, resulting in S-phase arrest and DNA damage. The compound exerted its anti-tumor properties through the activation of AIF-mediated apoptosis and the parthanatos pathway. In vivo studies using U251 and Ln229 cell xenografts supported the robust tumor-inhibitory capacity of O6-methyl-dGTP. In an orthotopic transplantation model with U87MG cells, O6-methyl-dGTP showcased marginally superior tumor-suppressive activity compared to TMZ. In summary, our research, for the first time, underscores the potential of O6-methyl-dGTP as an effective candidate against GBM, laying a robust scientific groundwork for its potential clinical adoption in GBM treatment regimens.

Recent Advances in Flexible CNC-Based Chiral Nematic Film Materials.

Cellulose nanocrystal (CNC) is a renewable resource derived from lignocellulosic materials, known for its optical permeability, biocompatibility, and unique self-assembly properties. Recent years have seen great progresses in cellulose nanocrystal-based chiral photonic materials. However, due to its inherent brittleness, cellulose nanocrystal shows limitations in the fields of flexible materials, optical sensors and food freshness testing. In order to solve the above limitations, attempts have been made to improve the flexibility of cellulose nanocrystal materials without destroying their structural color. Despite these progresses, a systematic review on them is lacking. This review aims to fill this gap by providing an overview of the main strategies and the latest research findings on the flexibilization of cellulose nanocrystal-based chiral nematic film materials (FCNM). Specifically, typical substances and methods used for their preparation are summarized. Moreover, different kinds of cellulose nanocrystal-based composites are compared in terms of flexibility. Finally, potential applications and future challenges of flexible cellulose nanocrystal-based chiral nematic materials are discussed, inspiring further research in this field.

[Preliminary Study on the Relationship between the Developmental Stage of Multiple Myeloma Disease and the Results of Bone Marrow Whole Exome Sequencing].

OBJECTIVE: To investigate the genetic results of whole exome sequencing of bone marrow from new onset multiple myeloma (MM) patients to analyze the process of genetic clonal evolution in MM patients. METHODS: Genomic DNA was extracted from bone marrow samples of 15 MM patients and the whole exomes sequencing was performed using next generation sequencing technology. Using own buccal cells as germline controls, combinated with clinical information, the mutation profile of genes from high-risk asymptomatic myeloma to symptomatic myeloma were analyzed, and genes that may be associated with the efficacy and side effects of bortezomib were screened. RESULTS: Except for two patients in whom no peripheral neuropathy was observed after a short treatment period, other patients peripheral neuropathy developed of various degrees during treatment with bortezomib containing chemotherapy, and the vast majority of patients achieved remission after receiving this bortezomib-related chemotherapy regimen. All patients had comparable levels of the inherited mutations number, but the somatic mutations was correlated with disease evolution. CONCLUSION: different gene "mutational spectra" exist in myeloma patients at different stages and are associated with progression through all stages of the disease.

The necroptosis signature and molecular mechanism of lung squamous cell carcinoma.

BACKGROUND: Given the poor prognosis of lung squamous cell carcinoma (LUSC), the aim of this study was to screen for new prognostic biomarkers. METHODS: The TGCA_LUSC dataset was used as the training set, and GSE73403 was used as the validation set. The genes involved in necroptosis-related pathways were acquired from the KEGG database, and the differential genes between the LUSC and normal samples were identified using the GSEA. A necroptosis signature was constructed by survival analysis, and its correlation with patient prognosis and clinical features was evaluated. The molecular characteristics and drug response associated with the necroptosis signature were also identified. The drug candidates were then validated at the cellular level. RESULTS: The TCGA_LUSC dataset included 51 normal samples and 502 LUSC samples. The GSE73403 dataset included 69 samples. 159 genes involved in necroptosis pathways were acquired from the KEGG database, of which most showed significant differences between two groups in terms of genomic, transcriptional and methylation alterations. In particular, CHMP4C, IL1B, JAK1, PYGB and TNFRSF10B were significantly associated with the survival (p < 0.05) and were used to construct the necroptosis signature, which showed significant correlation with patient prognosis and clinical features in univariate and multivariate analyses (p < 0.05). Furthermore, CHMP4C, IL1B, JAK1 and PYGB were identified as potential targets of trametinib, selumetinib, SCH772984, PD 325901 and dasatinib. Finally, knockdown of these genes in LUSC cells increased chemosensitivity to those drugs. CONCLUSION: We identified a necroptosis signature in LUSC that can predict prognosis and identify patients who can benefit from targeted therapies.

Targeting PRMT1-mediated SRSF1 methylation to suppress oncogenic exon inclusion events and breast tumorigenesis.

PRMT1 plays a vital role in breast tumorigenesis; however, the underlying molecular mechanisms remain incompletely understood. Herein, we show that PRMT1 plays a critical role in RNA alternative splicing, with a preference for exon inclusion. PRMT1 methylome profiling identifies that PRMT1 methylates the splicing factor SRSF1, which is critical for SRSF1 phosphorylation, SRSF1 binding with RNA, and exon inclusion. In breast tumors, PRMT1 overexpression is associated with increased SRSF1 arginine methylation and aberrant exon inclusion, which are critical for breast cancer cell growth. In addition, we identify a selective PRMT1 inhibitor, iPRMT1, which potently inhibits PRMT1-mediated SRSF1 methylation, exon inclusion, and breast cancer cell growth. Combination treatment with iPRMT1 and inhibitors targeting SRSF1 phosphorylation exhibits an additive effect of suppressing breast cancer cell growth. In conclusion, our study dissects a mechanism underlying PRMT1-mediated RNA alternative splicing. Thus, PRMT1 has great potential as a therapeutic target in breast cancer treatment.