Deciphering m6A signatures in hepatocellular carcinoma: Single-cell insights, immune landscape, and the protective role of IGFBP3.

RNA m6 methyladenosine (m6A) modifications impact tumor biology and immune processes, particularly in hepatocellular malignant tumors. Using a consensus clustering algorithm on 371 hepatocellular carcinoma (HCC) samples, we identified three m6A-modified subtypes and correlated them with positive tumor microenvironment (TME) markers for distinct immune phenotypes. Stratifying patients based on m6A scores revealed a low presentation group with better immune penetration, lower tumor mutation load, and increased expression of immune checkpoint markers like CTLA-4 and PD-1, suggesting enhanced responsiveness to immunization therapy. A machine-learning model of 23 m6A genes was constructed. Single-cell analysis revealed a surprising enrichment of IGFBP3 in astrocytes, prompting the exploration of associated signaling pathways. Experimental verification shows that IGFBP3 is significantly enhanced in normal tissues, while immunohistochemical analysis shows that its expression is lower in tumor tissues, indicating its protective effect in HCC and a good prognosis. Importantly, high IGFBP3 expression is associated with better outcomes in patients receiving immunotherapy. Moreover, cytotoxic T lymphocyte (CTL) experiments have confirmed that high expression of IGFBP3 is associated with stronger T cell-killing ability. In summary, the comprehensive evaluation of m6A modification, immune characteristics, and single-cell analysis in this study not only revealed the TME of HCC but also made significant contributions to the progress of personalized HCC immunotherapy targeting IGFBP3. This study provides a solid theoretical foundation for clinical translation and emphasizes its potential impact on developing effective treatment strategies.

Soluble TREM-1, as a new ligand for the membrane receptor Robo2, promotes hepatic stellate cells activation and liver fibrosis.

Triggering receptor expressed on myeloid cells-1 (TREM-1) exists in two forms: a transmembrane form and a soluble form (sTREM-1). The levels of sTREM-1 are elevated in supernatants of activated HSCs. However, the role of sTREM-1 in HSC activation and liver fibrosis remains undefined. Previous studies have primarily focused on the transmembrane form of TREM-1; we innovatively observed the function of sTREM-1 as a ligand in liver fibrosis and screened its receptor. Here, recombinant sTREM-1 was used as a stimulator which induced HSC activation and further aggravated liver fibrosis. Then, screening for sTREM-1 interacting membrane receptors was performed using pull-down assay followed by mass spectrometry, and the membrane receptor roundabout guidance receptor 2 (Robo2) was identified as a candidate receptor for sTREM-1. The interaction between sTREM-1 and Robo2 was verified by pull-down and immunofluorescence. The role of Robo2 on sTREM-1-induced HSC activation and its downstream signal pathways was assessed by knockdown of Robo2 in LX-2 cells. Furthermore, HSC-specific knockdown of Robo2 was achieved in a mouse model of liver fibrosis by using a recombinant adeno-associated virus (AAV) vector to confirm the role of the receptor, and we proved that Robo2 knockdown inhibited the activation of HSC and liver fibrosis, which also led to the inactivation of Smad2/3 and PI3K/Akt pathways in sTREM-1-induced HSC activation and liver fibrosis. In conclusion, sTREM-1 acts as a new ligand of Robo2; the binding of sTREM-1 to Robo2 initiates the activation of the downstream Smad2/3 and PI3K/Akt signalling pathways, thereby promoting HSC activation and liver fibrosis.

Inhibition of KIF20A enhances the immunotherapeutic effect of hepatocellular carcinoma by enhancing c-Myc ubiquitination.

Immune therapy has significantly improved the prognosis of hepatocellular carcinoma (HCC) patients, yet its efficacy remains limited, underscoring the urgency to identify new therapeutic targets and biomarkers. Here, we investigated the pathological and physiological roles of KIF20A and assess its potential in enhancing HCC treatment efficacy when combined with PD-1 inhibitors. We initially assess KIF20A's oncogenic function using liver-specific KIF20A knockout (Kif20a CKO) mouse models and orthotopic xenografts. Subsequently, we establish a regulatory axis involving KIF20A, FBXW7, and c-Myc, validated through construction of c-Myc splicing mutants. Large-scale clinical immunohistochemistry (IHC) analyses confirm the pathological relevance of the KIF20A-FBXW7-c-Myc axis in HCC. We demonstrate that KIF20A overexpression correlates with poor prognosis in HCC by competitively inhibiting FBXW7-mediated degradation of c-Myc, thereby promoting glycolysis and enhancing tumor proliferation. Conversely, KIF20A downregulation suppresses these effects, impairing tumor growth through c-Myc downregulation. Notably, KIF20A inhibition attenuates c-Myc-induced MMR expression, associated with improved prognosis in HCC patients receiving PD-1 inhibitor therapy. Furthermore, in Kif20a CKO HCC mouse models, we observe synergistic effects between Kif20a knockout and anti-PD-1 antibodies, significantly enhancing immunotherapeutic efficacy against HCC. Our findings suggest that targeting the KIF20A-c-Myc axis could identify HCC patients likely to benefit from anti-PD-1 therapy. In conclusion, we propose that combining KIF20A inhibitors with anti-PD-1 treatment represents a promising therapeutic strategy for HCC, offering new avenues for clinical development and patient stratification.

Long Noncoding RNA NR_030777 Alleviates Cobalt Nanoparticles-Induced Neurodegenerative Damage by Promoting Autophagosome-Lysosome Fusion.

Potential exposure to cobalt nanoparticles (CoNPs) occurs in various fields, including hard alloy industrial production, the increasing use of new energy lithium-ion batteries, and millions of patients with metal-on-metal joint prostheses. Evidence from human, animal, and in vitro experiments suggests a close relationship between CoNPs and neurotoxicity. However, a systematic assessment of central nervous system (CNS) impairment due to CoNPs exposure and the underlying molecular mechanisms is lacking. In this study, we found that CoNPs induced neurodegenerative damage both in vivo and in vitro, including cognitive impairment, ß-amyloid deposition and Tau hyperphosphorylation. CoNPs promoted the formation of autophagosomes and impeding autophagosomal-lysosomal fusion in vivo and in vitro, leading to toxic protein accumulation. Moreover, CoNPs exposure reduced the level of transcription factor EB (TFEB) and the abundance of lysosome, causing a blockage in autophagosomal-lysosomal fusion. Interestingly, overexpression of long noncoding RNA NR_030777 mitigated CoNPs-induced neurodegenerative damage in both in vivo and in vitro models. Fluorescence in situ hybridization assay revealed that NR_030777 directly binds and stabilizes TFEB mRNA, alleviating the blockage of autophagosomal-lysosomal fusion and ultimately restoring neurodegeneration induced by CoNPs in vivo and in vitro. In summary, our study demonstrates that autophagic dysfunction is the main toxic mechanism of neurodegeneration upon CoNPs exposure and NR_030777 plays a crucial role in CoNPs-induced autophagic dysfunction. Additionally, the proposed adverse outcome pathway contributes to a better understanding of CNS toxicity assessment of CoNPs.

Lactobacillus brevis alleviates the progress of hepatocellular carcinoma and type 2 diabetes in mice model via interplay of gut microflora, bile acid and NOTCH 1 signaling.

Type 2 diabetes (T2DM) clinically exhibits a higher incidence of hepatocellular carcinoma (HCC), contributing to a lousy prognosis in patients harboring both diseases. Microflora-based therapy draws attention with low side effects. Accumulating evidence shows that Lactobacillus brevis can improve blood glucose and body weight of the T2DM mice model and reduce several cancer incidences. However, the therapeutic effect of Lactobacillus brevis in affecting the prognosis of T2DM+HCC remains unknown. In this study, we aim to explore this question via an established T2DM+HCC mice model. We observed a significant alleviation after the probiotic intervention. Lactobacillus brevis improves blood glucose and insulin resistance and ameliorates Mechanically. Combined with a multi-omics approach including 16SrDNA, GC-MS, and RNA-seq, we identified distinct intestinal microflora composition and metabolites after Lactobacillus brevis intervention. Furthermore, we found that Lactobacillus brevis delayed disease progression by regulating MMP9 and NOTCH 1 signaling pathways, potentially through gut microflora and BA interaction. This study indicates that Lactobacillus brevis may improve the prognosis of T2DM + HCC, providing novel therapeutic opportunities via targeting intestinal flora for patients with T2DM+HCC.

Identification of lncRNAs based on different patterns of immune infiltration in gastric cancer.

Background: Gastric cancer is one of the most common malignant tumors in the world, which brings great challenges to people's life and health. The purpose of this study was to investigate immune related-lncRNAs and identify new biomarkers for the prognosis of gastric cancer (GC). Methods: We downloaded data from The Cancer Genome Atlas (TCGA) and used R software to determine the ESTIMATEScore, ImmuneScore, and StromalScore of each tumor sample. We performed prognostic analysis and identified the differentially expressed lnRNAs, which were then used to construct a prognostic model. Among the 44 hub genes in the competitive endogenous RNA (ceRNA) network, 3 differentially expressed genes were verified by qPCR. Results: Based on the degree of immune infiltration, cluster A had a higher ESTIMATEScore, ImmuneScore, and StromalScore and higher expression levels of PD-L1 (CD274) and CTLA4 than cluster B. Univariate Cox analysis was conducted for these differential lncRNAs, and 57 lncRNAs were found to have prognostic value (P<0.05). gene cluster A had a worse prognosis than gene cluster B (P=0.021). Then, a prognostic model was constructed. The low-risk group had a significantly higher survival rate. Finally, the qPCR results showed that the expression levels of BMPER, PRUNE2, and RBPMS2 were low in GC cell lines. Conclusions: We identified a risk score of 19 lncRNAs as a prognostic marker of GC. There was a relationship between these 19 prognostic-related lncRNAs and the subtypes of infiltrating immune cells. An approach for predicting the prognosis of GC was therefore provided in this study.

Immune-Related lncRNA Pairs Clinical Prognosis Model Construction for Hepatocellular Carcinoma.

BACKGROUND: Long non-coding RNA (lncRNA) plays an essential regulatory role in the occurrence and development of hepatocellular carcinoma (HCC). This paper aims to establish an immune-related lncRNA (irlncRNA) pairs model independent of expression level for risk assessment and prognosis prediction of HCC. METHODS: Transcriptome data and corresponding clinical data were downloaded from TCGA. HCC patients were randomly divided into training group and test group. Univariate Cox regression analysis, LASSO regression analysis, and stepwise multiple Cox regression analysis were used to establish a prognostic model. The prediction ability of the model was verified by ROC curves. Next, the patients were divided into low-risk and high-risk groups. We compared the differences between the two groups in survival rate, clinicopathological characteristics, tumor immune cell infiltration status, chemotherapeutic drug sensitivity and immunosuppressive molecules. RESULTS: A prognosis prediction model was established based on 7 irlncRNA pairs, namely irlncRNA pairs (IRLP). ROC curves of the training group and test group showed that the IRLP model had high sensitivity and specificity for survival prediction. Kaplan-Meier analysis showed that the survival rate of the high-risk group was significantly lower than that of the low-risk group. Immune cell infiltration analysis showed that the high-risk group was significantly correlated with various immune cell infiltration. Finally, there were statistically significant differences in chemosensitivity and molecular marker expression between the two groups. CONCLUSION: The prognosis prediction model established by irlncRNA pairs has a certain guiding significance for the prognosis prediction of HCC. It may provide valuable clinical applications in antitumor immunotherapy.

SERPINE1 Overexpression Promotes Malignant Progression and Poor Prognosis of Gastric Cancer.

The serine protease inhibitor clade E member 1 (SERPINE1) is a major inhibitor of tissue plasminogen activator and urokinase, and has been implicated in the development and progression of a variety of tumors. In this study, mRNA microarray and TCGA database were used to comprehensively analyze the upregulation of SERPINE1 in gastric cancer (GC) tissues compared with the normal stomach tissues. Kaplan-Meier results confirmed that patients with high SERPINE1 expression exhibited worse overall survival and disease-free survival. In addition, cell proliferation, cell scratches, transwell migration and invasion assay showed that SERPINE1 knockdown inhibited the proliferation, migration and invasion of GC ells. Western blot showed that the expression of VEGF and IL-6 was significantly upregulated after overexpression of SERPINE1. Meanwhile, SERPINE1 was positively correlated with the level of immune infiltration using the online analysis tools TISIDB and TIMER. And SERPINE1 expression increased with the increase of malignancy of GC which were detected by Immunohistochemistry. Finally, tumorigenesis experiments in nude mice further demonstrated that SERPINE1 could promote the occurrence and development of GC, while deletion of SERPINE1 inhibited the progression of GC. In summary, SERPINE1 was highly expressed in GC tissues, and SERPINE1 was helpful for differential diagnosis of pathological grade of gastric mucosal lesions. SERPINE1 might regulate the expression of VEGF and IL-6 through the VEGF signaling pathway and JAK-STAT3 inflammatory signaling pathway, thus ultimately affecting the invasion and migration of GC cells.

IPO5 Mediates EMT and Promotes Esophageal Cancer Development through the RAS-ERK Pathway.

Objective: In the development of many tumors, IPO5, as a member of the nuclear transporter family, exerts a significant function. Also, IPO5 is used as a therapeutic target for tumors based on some reports. By studying IPO5 expression in esophageal cancer tissues, the mechanism associated with IPO5 improving esophageal cancer development was explored in this study. Methods: To gain differentially expressed genes, this study utilized mRNA microarray and TCGA database for comprehensive analysis of esophageal cancer tissues and normal esophageal cancer tissues, and then the differentially expressed gene IPO5 was screened by us. To assess esophageal cancer patients' prognosis, this study also applied the Kaplan-Meier analysis, and we also conducted the GSEA enrichment analysis to investigate IPO5-related signaling pathways. This study performed TISIDB and TIMER online analysis tools to study the correlation between IPO5 and immune regulation and infiltration. We took specimens of esophageal cancer from patients and detected the expression of IPO5 in tumor and normal tissues by immunohistochemistry. The IPO5 gene-silenced esophageal cancer cell model was constructed by lentivirus transfection. Through the Transwell invasion assay, CCK-8 assay, and cell scratch assay, this study investigated the effects of IPO5 on cell propagation, invasion, and transfer. What is more, we identified the influences of IPO5 on the cell cycle through flow cytometry and established a subcutaneous tumor-forming model in nude mice. Immunohistochemistry was used to verify the expression of KI-67, and this study detected the modifications of cell pathway-related proteins using Western blot and applied EMT-related proteins to explain the mechanism of esophageal cancer induced by IPO5. Results: According to database survival analysis, IPO5 high-expression patients had shorter disease-free survival than IPO5 low-expression patients. Compared to normal tissues, the IPO5 expression in cancer tissues was significantly higher in clinical trials (P < 0.05). Through TISIDB and TIMER database studies, we found that IPO5 could affect immune regulation, and the age of IPO5 expression grows with the increase of immune infiltration level. The IPO5 expression in esophageal cancer cells was higher than normal, especially in ECA109 and OE33 cells (P < 0.01). After knocking out IPO5 gene expression, cell proliferation capacity and invasion capacity were reduced (P < 0.05) and decreased (P < 0.01) in the IPO5-interfered group rather than the negative control group. The growth cycle of esophageal carcinoma cells was arrested in the G2/M phase after IPO5 gene silencing (P < 0.01). Tumor-forming experiments in nude mice confirmed that after IPO5 deletion, the tumor shrank, the expression of KI67 decreased, the downstream protein expression level of the RAS pathway decreased after sh-IPO5 interference (P < 0.01), and the level of EMT marker delined (P < 0.05). Conclusion: In esophageal cancer, IPO5 is highly expressed and correlates with survival rate. Esophageal cancer cell growth and migration were significantly affected by the inhibition of IPO5 in vitro and in vivo. IPO5 mediates EMT using the RAS-ERK signaling pathway activation and promotes esophageal cancer cell development in vivo and in vitro.

A novel cuproptosis-related prognostic lncRNA signature for predicting immune and drug therapy response in hepatocellular carcinoma.

Intratumoral copper levels are closely associated with immune escape from diverse cancers. Cuproptosis-related lncRNAs (CRLs), however, have an unclear relationship with hepatocellular carcinoma (HCC). Gene expression data from 51 normal tissues and 373 liver cancer tissues from the Cancer Genome Atlas (TCGA) database were collected and analyzed. To identify CRLs, we employed differentially expressed protein-coding genes (DE-PCGs)/lncRNAs (DE-lncRNAs) analysis, Kaplan-Meier (K-M) analysis, and univariate regression. By univariate and Lasso Cox regression analyses, we screened 10 prognosis-related lncRNAs. Subsequently, five CRLs were identified by multivariable Cox regression analysis to construct the prognosis model. This feature is an independent prognostic indicator to forecast overall survival. According to Gene Set Variation Analysis (GSVA) and Gene Ontology (GO), both immune-related biological processes (BPS) and pathways have CRL participation. In addition, we found that the characteristics of CRLs were associated with the expression of the tumor microenvironment (TME) and crucial immune checkpoints. CRLs could predict the clinical response to immunotherapy based on the studies of tumor immune dysfunction and rejection (TIDE) analysis. Additionally, it was verified that tumor mutational burden survival and prognosis were greatly different between high-risk and low-risk groups. Finally, we screened potential sensitive drugs for HCC. In conclusion, this study provides insight into the TME status in patients with HCC and lays a basis for immunotherapy and the selection of sensitive drugs.

piR-823 inhibits cell apoptosis via modulating mitophagy by binding to PINK1 in colorectal cancer.

Mitophagy plays a vital role in the maintenance of mitochondrial homeostasis and tumorigenesis. Noncoding RNA piR-823 contributes to colorectal tumorigenesis. In this study, we aim to evaluate piR-823-mediated mitophagy and its mechanistic association with colorectal cancer (CRC). Digital gene expression analysis was performed to explore the potential functions of piR-823. A piR-823 antagomir (Ant-823) was used to inhibit piR-823 expression, and piR-823 mimics (mimics-823) were used to increase piR-823 expression. Mitophagy was measured in vivo and in vitro by immunofluorescence and western blot analysis. JC-1 staining, ATP production, real-time PCR, and western blot analysis were used to measure changes in mitochondrial quality and number. siRNA transfection was used to inhibit mitophagy, and CCCP was used to induce mitophagy. RNA pull-down assays and RNA-binding protein immunoprecipitation assays were conducted to investigate the molecular mechanisms. Here, we found that CRC cells transfected with Ant-823 presented an altered expression of autophagic and mitophagy genes by Digital gene expression analysis. Ant-823 could promote Parkin activation and mitophagy in vitro and in vivo, followed by mitochondrial loss and dysfunction of some mitochondria, whereas mimics-823 exerted the opposite effects in CRC cells. The inhibition of mitophagy by siParkin alleviated Ant-823-induced mitochondrial loss and dysfunction, as well as apoptosis to a certain extent. Furthermore, piR-823 was found to interact with PINK1 and promote its ubiquitination and proteasome-dependent degradation, thus alleviating mitophagy. Finally, these findings were verifed in samples obtained by patients affected by colorectal cancer. In conclusion, we identify a novel mechanism by which piR-823 regulates mitophagy during CRC tumorigenesis by increasing PINK1 degradation.

Characterization of the m6A-related lncRNA signature in predicting prognosis and immune response in patients with colon cancer.

PURPOSE: Colon adenocarcinoma (COAD) is globally one of the most frequently occurring malignant tumors. The patients' 5-year survival rate with colon cancer was poor. There is a usual form of mRNA modification called N6-methyl adenosine (m6A). It is adjusted by the m6A RNA methylation modulator. Nevertheless, few studies of COAD can fully discuss m6A-related lncRNAs' prognostic function. METHODS: From The Cancer Genome Atlas (TCGA) database, this study of COAD samples discussed 23 m6A regulator-related lncRNAs systemically. 2 m6A patterns with various clinical results were recognized, and a remarkable correlation between various m6A clusters and tumor immune microenvironment was discovered. RESULTS: According to prognostic analysis, cluster1 had a higher immune checkpoint programmed death-ligand 1 (PD-L1) expression and a better prognosis. A 6 m6A-related lncRNAs model was constructed through least absolute shrinkage and selection operator (LASSO), univariate, multivariate Cox regression and stratified analysis. The outcomes reported that compared with the low-risk group, high-risk groups that were based on model closely were related to poor overall survival (OS). The study ensured a risk model consisting of 6 m6A-related lncRNAs as independent prognosis predictors. For the expression differences between the two groups, Genomes Pathway Analysis, Kyoto Encyclopedia of Genes (KEGG) and Gene Ontology (GO) biological process analyses were conducted. In addition, on the basis of full analysis of OS, a nomogram based on gender, age, lncRNA feature and the stage was constructed. One year, two years, and three years are the periods when the calibration chart performed best. CONCLUSIONS: The outcomes of the study confirmed the underlying function of m6A-related lncRNAs and offered fresh perspectives to COAD prognosis.

Comprehensive bioinformatics analyses identified Homeobox B9 as a potential prognostic biomarker and therapeutic target for gastric cancer.

BACKGROUND: The Homeobox B (HOXB) family promotes tumor progression, but the mechanism of its action in gastric cancer (GC) is unclear. We sought to identify the HOXB family members that are critical to the prognosis of GC patients. METHODS: The Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, UALCAN, Kaplan-Meier plotter, and the GeneMANIA databases were used to analyze the messenger RNA (mRNA) expression levels, prognostic value, and gene-gene interaction network of the HOXB9 family members in GC. The expression of HOXB9 in GC and its relationship with various clinicopathological parameters and the prognosis of patients were verified by immunohistochemistry. RESULTS: The expression of HOXB3, HOXB5, HOXB6, HOXB7, HOXB9, and HOXB13 mRNA was significantly upregulated in GC. There was a significant correlation between the upregulation of HOXB3, HOXB5, and HOXB9 mRNA and a low overall survival (OS) rate. The high expression of HOXB7, HOXB9, and HOXB13 mRNA was closely correlated to tumor grade and stage. HOXB9 was the HOXB family member most closely related to the occurrence and development of GC. A further analysis showed that HOXB9 might be involved in deoxyribonucleic acid repair and division regulation. A validation study showed that the advanced cancer group had a higher level of HOXB9 expression than the early cancer group. The high expression of HOXB9 in gastric tissue plays an important role in the survival and prognosis of GC patients. CONCLUSIONS: HOXB family members have different degrees of abnormal expression in GC. High HOXB9 expression in GC tissues was significantly correlated with a worse prognosis. Thus, HOXB9 is a potential novel biomarker and therapeutic target for GC.

Six mutator-derived lncRNA signature of genome instability for predicting the clinical outcome of colon cancer.

BACKGROUND: Colon adenocarcinoma (COAD) is one of the most common malignancies worldwide. Genomic instability is one of the hallmarks of colon cancer and is associated with prognosis. Nevertheless, the impact of genome instability-associated long non-coding RNAs (lncRNAs) along with their clinical significance in cancers has remained mostly unexplored. METHODS: In this study, a mutator hypothesis-derived computational frame integrating the somatic mutation profiles and lncRNA expression profiles in a tumor genome was developed, which enabled the identification of 137 novel genomic instability-associated lncRNAs in colon cancer. Subsequently, a genome instability-derived lncRNA signature (GILncSig) segregated the patients into low- and high-risk groups with prominent differences in outcomes. RESULTS: Combined with the overall survival data, we established 6 six lncRNA-based signature to predict prognosis, which were LINC00896, AC007996.1, NKILA, AP003555.2, MIRLET7BHG, and AC009237.14. We found that the expression level of PD-L1 (CD274) and somatic mutations in the high-risk group were higher than those in the low-risk group. This suggests that high-risk patients may be sensitive to immunotherapy. We further found that the prognosis of patients in the high-risk group was significantly lower than that of patients in the low-risk group, and that patients' prognosis was likely to be worse as the patient's risk score increased. CONCLUSIONS: In conclusion, this study explores the role of lncRNAs in genomic instability and cancer prognosis and provides a new idea for the prognostic prediction of colon cancer.

Y-box binding protein 1 augments sorafenib resistance via the PI3K/Akt signaling pathway in hepatocellular carcinoma.

BACKGROUND: Sorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma (HCC). Y-box binding protein 1 (YB-1) is closely correlated with tumors and drug resistance. However, the relationship between YB-1 and sorafenib resistance and the underlying mechanism in HCC remain unknown. AIM: To explore the role and related mechanisms of YB-1 in mediating sorafenib resistance in HCC. METHODS: The protein expression levels of YB-1 were assessed in human HCC tissues and adjacent nontumor tissues. Next, we constructed YB-1 overexpression and knockdown hepatocarcinoma cell lines with lentiviruses and stimulated these cell lines with different concentrations of sorafenib. Then, we detected the proliferation and apoptosis in these cells by terminal deoxynucleotidyl transferase dUTP nick end labeling, flow cytometry and Western blotting assays. We also constructed a xenograft tumor model to explore the effect of YB-1 on the efficacy of sorafenib in vivo. Moreover, we studied and verified the specific molecular mechanism of YB-1 mediating sorafenib resistance in hepatoma cells by digital gene expression sequencing (DGE-seq). RESULTS: YB-1 protein levels were found to be higher in HCC tissues than in corresponding nontumor tissues. YB-1 suppressed the effect of sorafenib on cell proliferation and apoptosis. Consistently, the efficacy of sorafenib in vivo was enhanced after YB-1 was knocked down. Furthermore, KEGG pathway enrichment analysis of DGE-seq demonstrated that the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was essential for the sorafenib resistance induced by YB-1. Subsequently, YB-1 interacted with two key proteins of the PI3K/Akt signaling pathway (Akt1 and PIK3R1) as shown by searching the BioGRID and HitPredict websites. Finally, YB-1 suppressed the inactivation of the PI3K/Akt signaling pathway induced by sorafenib, and the blockade of the PI3K/Akt signaling pathway by LY294002 mitigated YB-1-induced sorafenib resistance. CONCLUSION: Overall, we concluded that YB-1 augments sorafenib resistance through the PI3K/Akt signaling pathway in HCC and suggest that YB-1 is a key drug resistance-related gene, which is of great significance for the application of sorafenib in advanced-stage HCC.