Clinical and genetic characteristics of patients with TRG 0 and TRG III in esophageal squamous cell carcinoma after neoadjuvant therapy.

Neoadjuvant therapy (NAT) is an important treatment for patients with resectable locally advanced esophageal squamous cell carcinoma (ESCC), but neoadjuvant resistance affects the overall treatment outcome. Therefore, it is particularly important to accurately screen the population for NAT and explore the mechanism of resistance. Usually, different chemotherapy regimens cause different drug resistance mechanisms. Prior to combining immunotherapy with chemotherapy, extensive research has been conducted on previous drug resistance mechanisms. Currently, the mainstream NAT for ESCC involves chemotherapy combined with immunotherapy. We have witnessed the remarkable effect of this combination therapy; however, there are still a considerable number of patients whose tumor tissues show no change or even progress after NAT, and their drug resistance mechanisms remain unclear. Hence, we aim to identify relevant evidence that can distinguish and predict the effectiveness of NAT from a clinical perspective in order to provide a clinical basis for future screening of suitable populations for NAT and discovery of drug resistance mechanisms. This study is based in China's high incidence area of esophageal cancer, where enrolled patients all receive the current mainstream NAT regimen resulting in more reliable outcomes.

NSUN2/YBX1 promotes the progression of breast cancer by enhancing HGH1 mRNA stability through m5C methylation.

BACKGROUND: RNA m5C methylation has been extensively implicated in the occurrence and development of tumors. As the main methyltransferase, NSUN2 plays a crucial regulatory role across diverse tumor types. However, the precise impact of NSUN2-mediated m5C modification on breast cancer (BC) remains unclear. Our study aims to elucidate the molecular mechanism underlying how NSUN2 regulates the target gene HGH1 (also known as FAM203) through m5C modification, thereby promoting BC progression. Additionally, this study targets at preliminarily clarifying the biological roles of NSUN2 and HGH1 in BC. METHODS: Tumor and adjacent tissues from 5 BC patients were collected, and the m5C modification target HGH1 in BC was screened through RNA sequencing (RNA-seq) and single-base resolution m5C methylation sequencing (RNA-BisSeq). Methylation RNA immunoprecipitation-qPCR (MeRIP-qPCR) and RNA-binding protein immunoprecipitation-qPCR (RIP-qPCR) confirmed that the methylation molecules NSUN2 and YBX1 specifically recognized and bound to HGH1 through m5C modification. In addition, proteomics, co-immunoprecipitation (co-IP), and Ribosome sequencing (Ribo-Seq) were used to explore the biological role of HGH1 in BC. RESULTS: As the main m5C methylation molecule, NSUN2 is abnormally overexpressed in BC and increases the overall level of RNA m5C. Knocking down NSUN2 can inhibit BC progression in vitro or in vivo. Combined RNA-seq and RNA-BisSeq analysis identified HGH1 as a potential target of abnormal m5C modifications. We clarified the mechanism by which NSUN2 regulates HGH1 expression through m5C modification, a process that involves interactions with the YBX1 protein, which collectively impacts mRNA stability and protein synthesis. Furthermore, this study is the first to reveal the binding interaction between HGH1 and the translation elongation factor EEF2, providing a comprehensive understanding of its ability to regulate transcript translation efficiency and protein synthesis in BC cells. CONCLUSIONS: This study preliminarily clarifies the regulatory role of the NSUN2-YBX1-m5C-HGH1 axis from post-transcriptional modification to protein translation, revealing the key role of abnormal RNA m5C modification in BC and suggesting that HGH1 may be a new epigenetic biomarker and potential therapeutic target for BC.

Aberrant m5C hypermethylation mediates intrinsic resistance to gefitinib through NSUN2/YBX1/QSOX1 axis in EGFR-mutant non-small-cell lung cancer.

BACKGROUND: RNA 5-methylcytosine (m5C) modification plays critical roles in the pathogenesis of various tumors. However, the function and molecular mechanism of RNA m5C modification in tumor drug resistance remain unclear. METHODS: The correlation between RNA m5C methylation, m5C writer NOP2/Sun RNA methyltransferase family member 2 (NSUN2) and EGFR-TKIs resistance was determined in non-small-cell lung cancer (NSCLC) cell lines and patient samples. The effects of NSUN2 on EGFR-TKIs resistance were investigated by gain- and loss-of-function assays in vitro and in vivo. RNA-sequencing (RNA-seq), RNA bisulfite sequencing (RNA-BisSeq) and m5C methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) were performed to identify the target gene of NSUN2 involved in EGFR-TKIs resistance. Furthermore, the regulatory mechanism of NSUN2 modulating the target gene expression was investigated by functional rescue and puromycin incorporation assays. RESULTS: RNA m5C hypermethylation and NSUN2 were significantly correlated with intrinsic resistance to EGFR-TKIs. Overexpression of NSUN2 resulted in gefitinib resistance and tumor recurrence, while genetic inhibition of NSUN2 led to tumor regression and overcame intrinsic resistance to gefitinib in vitro and in vivo. Integrated RNA-seq and m5C-BisSeq analyses identified quiescin sulfhydryl oxidase 1 (QSOX1) as a potential target of aberrant m5C modification. NSUN2 methylated QSOX1 coding sequence region, leading to enhanced QSOX1 translation through m5C reader Y-box binding protein 1 (YBX1). CONCLUSIONS: Our study reveals a critical function of aberrant RNA m5C modification via the NSUN2-YBX1-QSOX1 axis in mediating intrinsic resistance to gefitinib in EGFR-mutant NSCLC.

RNA Structural Dynamics Modulate EGFR-TKI Resistance Through Controlling YRDC Translation in NSCLC Cells.

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) positively affect the initial control ratio of non-small cell lung cancer (NSCLC). Rapidly acquired resistance to EGFR-TKI is a major hurdle in successful treatment. However, the mechanisms that control the resistance of EGFR-TKI remain largely unknown. RNA structures have widespread and crucial functions in many biological regulations; however, the functions of RNA structures in regulating cancer drug resistance remain unclear. Here, the psoralen analysis of RNA interactions and structures (PARIS) method is used to establish the higher-order RNA structure maps of EGFR-TKI-resistant and -sensitive cells of NSCLC. Our results show that RNA structural regions are enriched in untranslated regions (UTRs) and correlate with translation efficiency (TE). Moreover, yrdC N6-threonylcarbamoyltransferase domain containing (YRDC) promotes resistance to EGFR-TKI. RNA structure formation in YRDC 3' UTR suppresses embryonic lethal abnormal vision-like 1 (ELAVL1) binding, leading to EGFR-TKI sensitivity by impairing YRDC translation. A potential cancer therapy strategy is provided using antisense oligonucleotide (ASO) to perturb the interaction between RNA and protein. Our study reveals an unprecedented mechanism through which the RNA structure switch modulates EGFR-TKI resistance by controlling YRDC mRNA translation in an ELAVL1-dependent manner.

NSUN2-mediated mRNA m5C Modification Regulates the Progression of Hepatocellular Carcinoma.

RNA modification affects many biological processes and physiological diseases. The 5-methylcytosine (m5C) modification regulates the progression of multiple tumors. However, its characteristics and functions in hepatocellular carcinoma (HCC) remain largely unknown. Here, we found that HCC tissues had a higher m5C methylation level than the adjacent normal tissues. Transcriptome analysis revealed that a major function of the hypermethylated genes participated in the phosphokinase signaling pathways, such as the Ras and PI3K-Akt pathways. The m5C methyltransferase NSUN2 was highly expressed in HCC tissues. Interestingly, the expression of many genes was positively correlated with the expression of NSUN2, including GRB2, RNF115, AATF, ADAM15, RTN3, and HDGF. Real-time PCR assays further revealed that the expression of the mRNAs of GRB2, RNF115, and AATF decreased significantly with the down-regulation of NSUN2 in HCC cells. Furthermore, NSUN2 could regulate the cellular sensitivity of HCC cells to sorafenib via modulating the Ras signaling pathway. Moreover, knocking down NSUN2 caused cell cycle arrest. Taken together, our study demonstrates the vital role of NSUN2 in the progression of HCC.

Development and Verification of a Combined Immune- and Metabolism-Related Prognostic Signature for Hepatocellular Carcinoma.

Immune escape and metabolic reprogramming are becoming important characteristics of tumor biology, which play critical roles in tumor initiation and progression. However, the integrative analysis of immune and metabolic characteristics for the tumor microenvironment in hepatocellular carcinoma (HCC) remains unclear. Herein, by univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses, a prognostic signature associated with tumor microenvironment was established based on five immune- and metabolism-related genes (IMRGs), which was fully verified and evaluated in both internal and external cohorts. The C-index was superior to previously published HCC signatures, indicating the robustness and reliability of IMRGs prognostic signature. A nomogram was built based on IMRGs prognostic signature and various clinical parameters, such as age and T stage. The AUCs of nomogram at 1-, 3-, and 5-year (AUC = 0.829, 0.749, 0.749) were slightly better than that of IMRGs signature (AUC = 0.809, 0.734, 0.711). The relationship of risk score (RS) with immune checkpoint expressions, immunophenoscore (IPS), as well as microsatellite instability (MSI) together accurately predicted the treatment efficacy. Collectively, the IMRGs signature might have the potential to better predict prognostic risk, evaluate immunotherapy efficacy, and help personalize immunotherapy for HCC patients.

Design, Synthesis, and Biological Evaluation of 2-Anilino-4-Triazolpyrimidine Derivatives as CDK4/HDACs Inhibitors.

Purpose: To enhance the cytotoxicities of our obtained CDK4 inhibitors and get CDK4/HDACs inhibitors with potent enzymatic inhibitory and anti-proliferative activities. Methods: A series of novel CDK4/HDACs inhibitors were designed and synthesized by incorporating the HDAC pharmacophores (hydroxylamine or o-diaminoaniline) into the basic structure of our newly obtained 2-anilino-4-triazolpyrimidine based CDK4 inhibitors. The enzymatic inhibitory (HDAC1, CDK2, CDK4, and CDK6) activities and cytotoxicities of these compounds were evaluated. Moreover, HDAC isoforms inhibitory activity, cell cycle arrest assay, cell apoptosis analysis, cell migration, and cell colony formation assay were performed for the representative compound 11k. Results: Most of these compounds showed excellent HDAC1 inhibitory activities (IC50s: 0.68~244.5 nM) and anti-proliferative activities against cancer cell lines. Some compounds displayed potent CDK4 inhibitory activities and a certain selectivity towards CDK2 and CDK6. Compound 11k exhibited potent enzymatic (CDK4: IC50=23.59 nM; HDAC1: IC50=61.11 nM; HDAC2: IC50=80.62 nM; HDAC6: IC50=45.33 nM) and anti-proliferative activities against H460, MDA-MB-468, HCT116, and HepG2 cell lines with IC50 values 1.20, 1.34, 2.07, and 2.66 µM, respectively. Further mechanistic studies revealed that compound 11k could arrest the cell cycle in G0/G1 phase and induce apoptosis in HCT116 and MDA-MB-468 cells. In addition, compound 11k significantly inhibited the migration and cell colony formation of H460 and HCT116 cells. Conclusion: This study suggested that the incorporation of the HDAC pharmacophore into CDK4 inhibitor scaffold to design CDK/HDAC inhibitors might be a tractable strategy to enhance the antitumor potency of compounds.

MiR-93-5p regulates tumorigenesis and tumor immunity by targeting PD-L1/CCND1 in breast cancer.

Background: Challenges in medical care posed by rapid tumor progression, individualized responses to therapy, and the heterogeneous characteristics of breast cancer (BRCA) highlight the urgent need for new treatment strategies, as well as therapeutic and prognostic markers. Accumulating evidence has revealed that microRNAs broadly participate in carcinogenesis, but our understanding of the role of miR-93-5p in BRCA remains limited. Methods: The prognosis of miR-93-5p, programmed cell death-ligand 1 (PD-L1) and CCND1 were analyzed by datasets. Freshly excised breast cancer tissues (N=33) and adjacent noncancerous tissues (N=18) were collected to detect the expression of CCND1 and PD-L1 by immunohistochemistry (IHC). Quantitative real-time PCR (qRT-PCR) and Western blot were used to test the expression of miR-93-5p, PD-L1 and CCND1 after transfected mimics or inhibitors. Dual-luciferase reporter assay indicates the direct targeting between miR-93-5p and PD-L1. Results: Bioinformatics analysis demonstrated that miR-93-5p plays differential roles in various tumors, and further verification using qRT-PCR revealed that the expression levels of miR-93-5p were lower in MDA-MB-231 cells than in noncancerous breast cells. In addition, we confirmed that PD-L1 and CCND1 generated mutual effects, and miR-93-5p directly targets the PD-L1/CCND1 signaling pathway to influence their accumulation and distribution in the cell membrane, nucleus, and cytoplasm, mediating tumor progression and immune regulation in BRCA. Conclusions: Taken together, miR-93-5p could regulate tumorigenesis and tumor immunity by targeting PD-L1/CCND1 in BRCA and our research provides a rationale for therapy with miR-93-5p to overcome immune escape and improve risk stratification.

The Heterogeneity of Immune Cell Infiltration Landscape and Its Immunotherapeutic Implications in Hepatocellular Carcinoma.

Immunotherapy, closely associated with immune infiltration and tumor mutation burden (TMB), is emerging as a promising strategy for treating tumors, but its low response rate in hepatocellular carcinoma (HCC) remains a major challenge. Herein, we applied two algorithms to uncover the immune infiltration landscape of the immune microenvironment in 491 HCC patients. Three immune infiltration patterns were defined using the CIBERSORT method, and the immune cell infiltration (ICI) scores were established using principal component analysis. In the high ICI score group, the activation of the Wnt/ß-catenin pathway was significantly enriched and expressions of immune checkpoint genes increased, which showed a pessimistic outcome. The low ICI score group was characterized by increased TMB and enrichment of metabolism-related pathways. Further analysis found that the ICI score exhibited a significant difference in age ≥65/age <65, grade I/grade II-IV, and response to immunotherapy. Moreover, the CTNNB1 mutation status was found to be closely associated with prognosis and immunotherapeutic efficiency, significantly affecting the ICI score and TMB, which might be regarded as a potential marker for the treatment of HCC. The evaluation of immune infiltration patterns can improve the understanding of the tumor immune microenvironment and provide new directions for the study of individualized immunotherapy strategies for HCC.

Metformin attenuated sepsis-related liver injury by modulating gut microbiota.

Increased evidence shows that gut microbiota acts as the primary regulator of the liver; however, its role in sepsis-related liver injury (SLI) in the elderly is unclear. This study assessed whether metformin could attenuate SLI by modulating gut microbiota in septic-aged rats. Cecal ligation and puncture (CLP) was used to induce SLI in aged rats. Fecal microbiota transplantation (FMT) was used to validate the roles of gut microbiota in these pathologies. The composition of gut microbiota was analysed by 16S rRNA sequencing. Moreover, the liver and colon tissues were analysed by histopathology, immunofluorescence, immunohistochemistry, and reverse transcription polymerase chain reaction (RT-PCR). Metformin improved liver damage, colon barrier dysfunction in aged SLI rats. Moreover, metformin improved sepsis-induced liver inflammation and damage under gut microbiota. Importantly, FMT assay showed that rats gavaged with faeces from metformin-treated SLI rats displayed less severe liver damage and colon barrier dysfunctions than those gavaged with faeces from SLI rats. The gut microbiota composition among the sham-operated, CLP-operated and metformin-treated SLI rats was different. In particular, the proportion of Klebsiella and Escherichia_Shigella was higher in SLI rats than sham-operated and metformin-treated SLI rats; while metformin could increase the proportion of Bifidobacterium, Muribaculaceae, Parabacteroides_distasonis and Alloprevitella in aged SLI rats. Additionally, Klebsiella and Escherichia_Shigella correlated positively with the inflammatory factors in the liver. Our findings suggest that metformin may improve liver injury by regulating the gut microbiota and alleviating colon barrier dysfunction in septic-aged rats, which may be an effective therapy for SLI.

Disturbance of hepatocyte growth and metabolism in a hyperammonemia microenvironment.

BACKGROUND: We found through previous research that hyperammonemia can cause secondary liver damage. However, whether hepatocytes are target cells of ammonia toxicity and whether hyperammonemia affects hepatocyte metabolism remain unknown. AIMS: The purpose of the current study is to examine whether the hepatocyte is a specific target cell of ammonia toxicity and whether hyperammonemia can interfere with hepatocyte metabolism. METHODS: Cell viability and apoptosis were analyzed in primary hepatocytes and other cells that had been exposed to ammonium chloride. Western blotting was adopted to examine the expression of proteins related to ammonia transport. We also established a metabolomics method based on gas chromatography-mass spectrometry to understand the characteristics of the hepatocyte metabolic spectrum in a hyperammonemia microenvironment, to screen and identify differential metabolites, and to determine the differential metabolic pathway. Different technologies were used to verify the differential metabolic pathways. RESULTS: Hepatocytes are target cells of ammonia toxicity. The mechanism is related to the ammonia transporter. Hyperammonemia interferes with hepatocyte metabolism, which leads to TCA cycle, urea cycle, and RNA synthesis disorder. CONCLUSIONS: This study demonstrates that hepatocyte growth and metabolism are disturbed in a hyperammonemia microenvironment, which further deteriorates hepatocyte function.

High miR-3609 expression is associated with better prognosis in TNBC based on mining using systematic integrated public sequencing data.

MicroRNAs (miRNAs/miRs) are small endogenous RNAs that regulate gene expression post-transcriptionally. Abnormal miR-3609 expression is associated with the occurrence of pancreatic cancer, glioma and other diseases, such as polycystic ovary syndrome. However, the prognostic potential of miR-3609 has been reported in breast cancer. Thus, the present study aimed to investigate the differential expression and prognostic value of miR-3609 in patients with breast cancer from the UALCAN, cBioportal and Kaplan-Meier Plotter databases, respectively. Furthermore, the co-expression genes of miR-3609 in breast cancer were investigated using data from the LinkedOmics database, and functional enrichment analysis was performed using the LinkInterpreter module in LinkedOmics. The co-expression gene network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins database, and the cytoHubba plug-in was used to identify the hub genes, which were visualized using Cytoscape software. The prognoses of the hub genes were performed using the Kaplan-Meier Plotter database. The Cell Counting Kit-8 and cell cycle assays were performed to confirm the functions of miR-3609 mimics transfection in MDA-MB-231 cells. Survival analysis using the Kaplan-Meier Plotter database demonstrated that high miR-3609 expression in triple-negative breast cancer (TNBC) was associated with a better prognosis. Furthermore, the experimental results indicated that high miR-3609 expression inhibited the proliferation of TNBC cells and induced cell cycle arrest of TNBC cells in the G0/G1 phase. Taken together, the results of the present study suggest that miR-3609 plays a vital role in mediating cell cycle arrest and inhibiting the proliferation of TNBC cells.

Selective synergistic anticancer effects of cisplatin and oridonin against human p53-mutant esophageal squamous carcinoma cells.

Oridonin (ORI) is known to pose anticancer activity against cancer, which could induce the therapeutic impact of chemotherapy drugs. However, such simple combinations have numerous side effects such as higher toxicity to normal cells and tissues. To enhance the therapeutic effects with minimal side effects, here we used ORI in combination with cisplitin (CIS) against different esophageal squamous cell carcinoma (ESCC) cell lines in vitro, to investigate the synergistic anticancer effects of the two drugs against ESCC. Calcusyn Graphing Software was used to assess the synergistic effect. Apoptosis, wound healing and cell invasion assay were conducted to further confirm the synergistic effects of ORI and CIS. Intracellular glutathione (GSH) and reactive oxygen species assay, immunofluorescence staining and western blot were used to verify the mechanism of synergistic cytotoxicity. ORI and CIS pose selective synergistic effects on ESCC cells with p53 mutations. Moreover, we found that the synergistic effects of these drugs are mediated by GSH/ROS systems, such that intracellular GSH production was inhibited, whereas the ROS generation was induced following ORI and CIS application. In addition, we noted that DNA damage was induced as in response to ORI and CIS treatment. Overall, these results suggest that ORI can synergistically enhance the effect of CIS, and GSH deficiency and p53 mutation, might be biomarkers for the combinational usage of ORI and CIS.

EGR1-CCL2 Feedback Loop Maintains Epithelial-Mesenchymal Transition of Cisplatin-Resistant Gastric Cancer Cells and Promotes Tumor Angiogenesis.

BACKGROUND: The mechanism of cisplatin resistance in gastric cancer (GC) is still elusive; several recent evidences proposed that chemoresistant tumor cells acquired aggressive behaviors. AIMS: This study was aimed to investigate the mechanism of epithelial-mesenchymal transition (EMT) and angiogenesis in chemoresistant GC. METHODS: Bioinformatics analysis and function or mechanism experiments including RT-qPCR, immunofluorescence, Western blot, luciferase reporter assay, Chromatin immunoprecipitation, Chicken chorioallantoic membrane assay and animal experiments were applied to evaluate the role of EGR1-CCL2 feedback loop. RESULTS: Compared with the parental cell line SGC7901, cisplatin resistant SGC7901R cells underwent EMT and showed increased angiogenic capabilities. Mechanistically, SGC7901R cells showed increased levels of EGR1, which could transcriptionally activate the angiogenic factor CCL2 and EMT regulator ZEB2. Reciprocally, CCL2 activated the CCR2-ERK-ELK1-EGR1 pathway, thus forming a positive feed-forward loop. Moreover, CCL2 in culture medium of SGC7901R cells promoted angiogenesis of Human Umbilical Vein Endothelial Cells (HUVECs). EGR1 expression was positively correlated with CCL2 and ZEB2 in clinical GC tissues, and the depletion of ERG1 could also decrease microvessel density and ZEB2 expression in metastatic nodules of nude mice. CONCLUSIONS: EGR1-CCL2 feedback loop might exert critical roles on EMT and angiogenesis of chemoresistant GC.