SIX4 promotes hepatocellular carcinoma metastasis through upregulating YAP1 and c-MET

Sine oculis homeobox homolog family function in gastrointestinal cancer: Progression and comprehensive analysis

The sine oculis homeobox homolog (SIX) family, a group of transcription factors characterized by a conserved DNA-binding homology domain, plays a critical role in orchestrating embryonic development and organogenesis across various organisms, including humans. Comprising six distinct members, from SIX1 to SIX6, each member contributes uniquely to the development and differentiation of diverse tissues and organs, underscoring the versatility of the SIX family. Dysregulation or mutations in SIX genes have been implicated in a spectrum of developmental disorders, as well as in tumor initiation and progression, highlighting their pivotal role in maintaining normal developmental trajectories and cellular functions. Efforts to target the transcriptional complex of the SIX gene family have emerged as a promising strategy to inhibit tumor development. While the development of inhibitors targeting this gene family is still in its early stages, the significant potential of such interventions holds promise for future therapeutic advances. Therefore, this review aimed to comprehensively explore the advancements in understanding the SIX family within gastrointestinal cancers, focusing on its critical role in normal organ development and its implications in gastrointestinal cancers, including gastric, pancreatic, colorectal cancer, and hepatocellular carcinomas. In conclusion, this review deepened the understanding of the functional roles of the SIX family and explored the potential of utilizing this gene family for the diagnosis, prognosis, and treatment of gastrointestinal cancers.

Efficacy and safety of multi-target tyrosine kinase inhibitor AL2846 combined with gemcitabine in pancreatic cancer

Pancreatic cancer patients urgently need new treatments, and we explored the efficacy and safety of combination therapy with AL2846 and gemcitabine in pancreatic cancer patients. This was a single-arm, single-center, open-label phase I/IIa study (NCT06278493). The dose-escalation phase was designed to evaluate the maximum tolerated dose (MTD) of AL2846 combined with gemcitabine. One or two dose levels were chosen for the dose-expansion phase. Treatment continued until disease progression, intolerable toxicity, patient withdrawal, or at the investigators' discretion. The primary study endpoint is to evaluate the safety and MTD of AL2846 combined with gemcitabine. The secondary endpoints included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and disease control rate (DCR). Between August 2018 and July 2021, 33 pancreatic cancer patients were enrolled in the study. A total of 15 patients were enrolled in the dose-escalation phase, and the MTD was not determined. Eventually 90 mg and 120 mg of AL2846 were chosen for the dose-expansion phase, in which 11 patients (90 mg) and 7 patients (120 mg) were administered. Treatment-related adverse events (TRAEs) of any grade were reported in 30 (90.91%) patients, and those of grade ≥ 3 were reported in 16 (48.48%) patients. The most frequently reported grade ≥ 3 TRAEs were thrombocytopenia (18.18%), neutropenia (12.12%), elevated γ-glutamyltransferase (6.06%), proteinuria (6.06%), and gastrointestinal hemorrhage (6.06%).The ORR was 6.06%, and the DCR was 72.73%. The median PFS was 3.71 months (95% CI: 3.38-4.11), and the median OS was 5.59 months (95% CI: 4.11-8.71). Gemcitabine and Al2846 combination therapy exhibited tolerable safety, but there was no improvement in efficacy over standard treatment. Further evaluation of this approach is still needed.

Hinokiflavone exerts dual regulation on apoptosis and pyroptosis via the SIX4/Stat3/Akt pathway to alleviate APAP-induced liver injury

Hinokiflavone (HF), classified as a flavonoid, is a main bioactive compound in Platycladus orientalis and Selaginella. HF exhibits activities including anti-HIV, anti-inflammatory, antiviral, antioxidant and anti-tumor effects. The study aimed to explore the function and the mechanisms of HF on acetaminophen (APAP)-induced acute liver injury. Results indicated that HF treatment mitigated the impact of APAP on viability and restored levels of MDA, GSH and SOD on HepG2 cells. The accumulation of reactive oxygen species (ROS) mitochondrial membrane potential (MMP) in HepG2 cells stimulated by APAP were also blocked by HF. HF reduced the levels of pro-apoptotic and pro-pyroptotic proteins. Flow cytometry analysis and fluorescence staining results were consistent with western blot analysis. Following HF treatment in the APAP-induced cell model, there was observed an augmentation in the phosphorylation of Stat3 and an increase in the expression of SIX4. However, not only silenced the SIX4 protein in HepG2 cells by siRNA, but also adding the Stat3 inhibitor (Stattic), attenuated the anti-apoptotic and anti-pyroptotic effects of HF significantly. Furthermore, HF alleviated liver damage in C57BL/6 mice model. Overall, our study demonstrated that HF mitigates apoptosis and pyroptosis induced by APAP in drug-induced liver injury (DILI) through the SIX4/Akt/Stat3 pathway in vivo and in vitro. HF may have promising potential for for the treatment of DILI.

Dual role of Nrf2 signaling in hepatocellular carcinoma: promoting development, immune evasion, and therapeutic challenges

Hepatocellular carcinoma (HCC) is the predominant form of liver cancer and ranks as the third leading cause of cancer-related mortality globally. The liver performs a wide range of tasks and is the primary organ responsible for metabolizing harmful substances and foreign compounds. Oxidative stress has a crucial role in growth and improvement of hepatocellular carcinoma (HCC). Nuclear factor erythroid 2 (1)-related factor 2 (Nrf2) is an element that regulates transcription located in the cytoplasm. It controls the balance of redox reactions by stimulating the expression of many genes that depend on antioxidant response elements. Nrf2 has contrasting functions in the normal, healthy liver and HCC. In the normal liver, Nrf2 provides advantageous benefits, while in HCC it promotes harmful effects that support the growth and survival of HCC. Continuous activation of Nrf2 has been detected in HCC and promotes its advancement and aggressiveness. In addition, Activation of Nrf2 may lead to immune evasion, weakening the immune cells' ability to attack tumors and thereby promoting tumor development. Furthermore, chemoresistance in HCC, which is considered a form of stress response to chemotherapy medications, significantly impedes the effectiveness of HCC treatment. Stress management is typically accomplished by activating specific signal pathways and chemical variables. One important element in the creation of chemoresistance in HCC is nuclear factor-E2-related factor 2 (Nrf2). Nrf2 is a transcription factor that regulates the activation and production of a group of genes that encode proteins responsible for protecting cells from damage. This occurs through the Nrf2/ARE pathway, which is a crucial mechanism for combating oxidative stress within cells.

Resveratrol suppresses NSCLC cell growth, invasion and migration by mediating Wnt/β-catenin pathway via downregulating SIX4 and SPHK2

Resveratrol (RSV) has been found to have a cancer-suppressing effect in a variety of cancers, including non-small cell lung cancer (NSCLC). Studies have shown that sine oculis homeobox 4 (SIX4) and sphingosine kinase 2 (SPHK2) are tumour promoters of NSCLC. However, whether RSV regulates SIX4 and SPHK2 to mediate NSCLC cell functions remains unclear. NSCLC cell functions were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry, transwell assay and wound healing assay. Protein expression levels were detected by western blot. SIX4 and SPHK2 mRNA levels in NSCLC tumour tissues were examined using quantitative real-time PCR. In addition, mice xenograft models were built to explore the impact of RSV on NSCLC tumour growth. RSV inhibited NSCLC cell proliferation, invasion and migration, while facilitated apoptosis. SIX4 and SPHK2 were up-regulated in NSCLC tissues and cells, and their expression was reduced by RSV. Knockdown of SIX4 and SPHK2 suppressed NSCLC cell growth, invasion and migration, and the regulation of RSV on NSCLC cell functions could be reversed by SIX4 and SPHK2 overexpression. RSV inactivated Wnt/β-catenin pathway via decreasing SIX4 and SPHK2 levels. In animal experiments, RSV reduced NSCLC tumour growth in vivo. RSV repressed NSCLC malignant process by decreasing SIX4 and SPHK2 levels to restrain the activity of Wnt/β-catenin pathway.

miR-540-3p partially recovers the locomotor function of spinal cord injury mice by targeting SIX4/Yap1 and inactivation of astrocytes

BACKGROUND

Spinal cord injury (SCI) lacks therapeutic reagents. miRNAs are responsible for mesenchymal stem cells (MSCs) therapy in spinal cord injury.

PURPOSE

To discover the underlying therapeutic miRNA target and its mechanism for the treatment of SCI.

METHOD

Two RNA sequence datasets were retrieved from the GEO Datasets database which was accessed on 30 December 2023. The targets of the top 2 ranked miRNAs (miR-540-3p and miR-433-5p) were analyzed using online databases (miRDB, miRMap, TargetScan and STRING database) and both miRNAs were screened by cell counting kit-8 (CCK-8) assay. Then, transfection and local injection of miR-540-3p were performed to examine the capacity of secretion of astrocytes and the locomotor function of SCI mice.

RESULTS

The significantly high levels of miR-540-3p/433-5p were revealed. Transfection of miR-540-3p conferred inactivation of reactive astrocytes and weakened the capacity of secreting inflammatory cytokines of astrocytes. miR-433-5p was proven to not impact the proliferation of astrocytes. Co-culture of culture supernate from astrocytes transfected with miR-540-3p and neurons demonstrated the significantly preserved neurite length and decreased apoptotic level of neurons. Meanwhile, sine oculis homeobox (SIX4)/Yap1, as the target of miR-540-3p, is critical for abrogating inflammatory damage of neurons in vivo and in vitro, decreasing glial scar, and recovering locomotor function of spinal cord injury mice. Furthermore, SCI mice receiving a local injection of miR-540-3p showed smaller and lighter bladder volume and higher limb strength, but the period from urinary retention to autonomous urination of SCI mice showed no significance.

CONCLUSIONS

Conclusively, miR-540 discovered from hypoxia-treated exosomes suppresses the inflammatory cytokines secreted by reactive astrocytes, partially preserves the neuronal function of spinal cord injury mice, through the SIX4/Yap1 signalling pathway.

Metastasis and basement membrane-related signature enhances hepatocellular carcinoma prognosis and diagnosis by integrating single-cell RNA sequencing analysis and immune microenvironment assessment

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and second leading cause of cancer-related deaths worldwide. The heightened mortality associated with HCC is largely attributed to its propensity for metastasis, which cannot be achieved without remodeling or loss of the basement membrane (BM). Despite advancements in targeted therapies and immunotherapies, resistance and limited efficacy in late-stage HCC underscore the urgent need for better therapeutic options and early diagnostic biomarkers. Our study aimed to address these gaps by investigating and evaluating potential biomarkers to improve survival outcomes and treatment efficacy in patients with HCC.

METHOD

In this study, we collected the transcriptome sequencing, clinical, and mutation data of 424 patients with HCC from The Cancer Genome Atlas (TCGA) and 240 from the International Cancer Genome Consortium (ICGC) databases. We then constructed and validated a prognostic model based on metastasis and basement membrane-related genes (MBRGs) using univariate and multivariate Cox regression analyses. Five immune-related algorithms (CIBERSORT, QUANTISEQ, MCP counter, ssGSEA, and TIMER) were then utilized to examine the immune landscape and activity across high- and low-risk groups. We also analyzed Tumor Mutation Burden (TMB) values, Tumor Immune Dysfunction and Exclusion (TIDE) scores, mutation frequency, and immune checkpoint gene expression to evaluate immune treatment sensitivity. We analyzed integrin subunit alpha 3 (ITGA3) expression in HCC by performing single-cell RNA sequencing (scRNA-seq) analysis using the TISCH 2.0 database. Lastly, wound healing and transwell assays were conducted to elucidate the role of ITGA3 in tumor metastasis.

RESULTS

Patients with HCC were categorized into high- and low-risk groups based on the median values, with higher risk scores indicating worse overall survival. Five immune-related algorithms revealed that the abundance of immune cells, particularly T cells, was greater in the high-risk group than in the low-risk group. The high-risk group also exhibited a higher TMB value, mutation frequency, and immune checkpoint gene expression and a lower tumor TIDE score, suggesting the potential for better immunotherapy outcomes. Additionally, scRNA-seq analysis revealed higher ITGA3 expression in tumor cells compared with normal hepatocytes. Wound healing scratch and transwell cell migration assays revealed that overexpression of the MBRG ITGA3 enhanced migration of HCC HepG2 cells.

CONCLUSION

This study established a direct molecular correlation between metastasis and BM, encompassing clinical features, tumor microenvironment, and immune response, thereby offering valuable insights for predicting clinical outcomes and immunotherapy responses in HCC.

Multimodal Imaging-Guided Synergistic Photodynamic Therapy Using Carbonized Zn/Co Metal-Organic Framework Loaded with Cytotoxin Against Liver Cancer

Purpose

The study aimed to address the non-specific toxicity of cytotoxins (CTX) in liver cancer treatment and explore their combined application with the photosensitizer Ce6, co-loaded into carbonized Zn/Co bimetallic organic frameworks. The goal was to achieve controlled CTX release and synergistic photodynamic therapy, with a focus on evaluating anti-tumor activity against human liver cancer cell lines (Hep G2).

Methods

Purified cobra cytotoxin (CTX) and photosensitizer Ce6 were co-loaded into carbonized Zn/Co bimetallic organic frameworks, resulting in RGD-PDA@C-ZIF@(CTX+Ce6). The formulation was designed with surface-functionalization using polydopamine and tumor-penetrating peptide RGD. This approach aimed to facilitate controlled CTX release and enhance the synergistic effect of photodynamic therapy. The accumulation of RGD-PDA@C-ZIF@(CTX+Ce6) at tumor sites was achieved through RGD's active targeting and the enhanced permeability and retention (EPR) effect. In the acidic tumor microenvironment, the porous structure of the metal-organic framework disintegrated, releasing CTX and Ce6 into tumor cells.

Results

Experiments demonstrated that RGD-PDA@C-ZIF@(CTX+Ce6) nanoparticles, combined with near-infrared laser irradiation, exhibited optimal anti-tumor effects against human liver cancer cells. The formulation showcased heightened anti-tumor activity without discernible systemic toxicity.

Conclusion

The study underscores the potential of utilizing metal-organic frameworks as an efficient nanoplatform for co-loading cytotoxins and photodynamic therapy in liver cancer treatment. The developed formulation, RGD-PDA@C-ZIF@(CTX+Ce6), offers a promising avenue for advancing the clinical application of cytotoxins in oncology, providing a solid theoretical foundation for future research and development.

The Hippo-YAP signaling pathway drives CD24-mediated immune evasion in esophageal squamous cell carcinoma via macrophage phagocytosis

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies in the world with poor prognosis. Despite the promising applications of immunotherapy, the objective response rate is still unsatisfactory. We have previously shown that Hippo/YAP signaling acts as a powerful tumor promoter in ESCC. However, whether Hippo/YAP signaling is involved in tumor immune escape in ESCC remains largely unknown. Here, we show that YAP directly activates transcription of the "don't eat me" signal CD24, and plays a crucial role in driving tumor cells to avoid phagocytosis by macrophages. Mechanistically, YAP regulates CD24 expression by interacting with TEAD and binding the CD24 promoter to initiate transcription, which facilitates tumor cell escape from macrophage-mediated immune attack. Our animal model data and clinical data show that YAP combined with CD24 in tumor microenvironment redefines the impact of TAMs on the prognosis of ESCC patients which will provide a valuable basis for precision medicine. Moreover, treatment with YAP inhibitor altered the distribution of macrophages and suppressed tumorigenesis and progression of ESCC in vivo. Together, our study provides a novel link between Hippo/YAP signaling and macrophage-mediated immune escape, which suggests that the Hippo-YAP-CD24 axis may act as a promising target to improve the prognosis of ESCC patients. A proposed model for the regulatory mechanism of Hippo-YAP-CD24-signaling axis in the tumor-associated macrophages mediated immune escape.

SIX4 Controls Anti-PD-1 Efficacy by Regulating STING Expression

The cGAS/STING cytosolic DNA-sensing pathway plays a significant role in antitumor immunity. Expression of STING is tightly regulated and commonly reduced or defective in many types of cancer. We have identified SIX4 as a significant regulator of STING expression in colon cancer cells. We showed that knockout of SIX4 decreased STING expression at the mRNA and protein levels while ectopic expression of SIX4 increased STING expression. Depletion of SIX4 led to attenuated STING activation and downstream signaling. Reexpression of SIX4 or ectopic expression of STING in SIX4 knockout cells reversed the effect. Ectopic expression of SIX4 enhanced DMXAA and cGAMP-induced STING activation and downstream signaling. Importantly, decrease of SIX4 expression substantially decreased tumor infiltration of CD8+ T cells and reduced the efficacy of PD-1 antibodies to diminish tumor growth in immune competent mice in vivo. Finally, analysis of The Cancer Genome Atlas colon cancer dataset indicated that tumors with high SIX4 expression were significantly enriched in the Inflammatory Response pathway. SIX4 expression also correlated with expression of multiple IFN-stimulated genes, inflammatory cytokines, and CD8A. Taken together, our results implicate that SIX4 is a principal regulator of STING expression in colon cancer cells, providing an additional mechanism and genetic marker to predict effective immune checkpoint blockade therapy responses.

SIGNIFICANCE

Our studies demonstrate that SIX4 is an important regulator of STING expression, providing a genetic marker or a therapeutic target to predict or enhance immune checkpoint blockade therapy responses in colon cancer.

Combination of SIX4-siRNA and temozolomide inhibits the growth and migration of A-172 glioblastoma cancer cells

Glioblastoma is one of the most common and invasive types of primary brain malignancies in adults, accounting for 45.5% of malignancies. Its annual prevalence is low compared to other cancers. The survival rate of this disease is about 14 months after diagnosis. Temozolomide (TMZ) is a common chemotherapy drug used to treatment of glioblastoma, but drug resistance against this drug is an important barrier to successful treatment of this cancer. Today, siRNAs play a significant role in cancer treatment. SIX4 is a transcriptional regulatory molecule that can act as a transcriptional suppressor and an activator in target genes involved in differentiation, migration, and cell survival processes. The aim of this study was to evaluate the effect of SIX4-siRNA on A-172 glioblastoma cells, its role as a tumor suppressor, and its combination with TMZ. We studied the cytotoxic effect of the SIX4-siRNA and TMZ on A-172 cells using the MTT assay investigated their effect on apoptosis and cell cycle of A-172 cells used wound healing assays to assess their effect on cell migration. Finally, we used qRT-PCR to study the mRNA expression levels of genes involved in apoptosis and migration of tumoral cells after treatments. Based on our results, silencing SIX4-siRNA expression reduced the cell viability of A-172 cells and sensitize these cells to TMZ. Furthermore, we observed an increase in apoptosis and cell cycle arrest, and a decrease in migration. Bax and caspase-9 overexpression and BCL2 and MMP9 downregulation were detected in the combination of SIX4-siRNA and TMZ. According to our results, the combination of SIX4-siRNA and TMZ can be a very useful strategy for successful glioblastoma treatment.

SIX4, a potential therapeutic target for estrogen receptor-positive breast cancer patients, is associated with low promoter methylation level

Aim: To investigate SIX4 in breast cancer. Methods: Publicly available online tools were used to analyze the expression, methylation and prognostic significance of SIX4 in breast cancer, as well as its immunohistochemistry. Results: High SIX4 levels were associated with low SIX4 promoter methylation, especially in estrogen receptor-positive breast cancer. Increased SIX4 was related to advanced stage and decreased immune infiltration. Gene set enrichment analysis found that the SIX4-correlated genes were enriched in transcriptional processing and immune response. Patients with high SIX4 expression tended to have poor survival, especially those with estrogen receptor-positive breast cancer. Conclusion: High SIX4 expression in breast cancer plays an oncogenic role, promoting the development of malignancies through suppressing the immune response, especially in luminal subtypes, and is associated with a low promoter methylation level.

Transcription factor glucocorticoid modulatory element-binding protein 1 promotes hepatocellular carcinoma progression by activating Yes-associate protein 1

BACKGROUND

Glucocorticoid modulatory element-binding protein 1 (GMEB1), which has been identified as a transcription factor, is a protein widely expressed in various tissues. Reportedly, the dysregulation of GMEB1 is linked to the genesis and development of multiple cancers.

AIM

To explore GMEB1’s biological functions in hepatocellular carcinoma (HCC) and figuring out the molecular mechanism.

METHODS

GMEB1 expression in HCC tissues was analyzed employing the StarBase database. Immunohistochemical staining, Western blotting and quantitative real-time PCR were conducted to examine GMEB1 and Yes-associate protein 1 (YAP1) expression in HCC cells and tissues. Cell counting kit-8 assay, Transwell assay and flow cytometry were utilized to examine HCC cell proliferation, migration, invasion and apoptosis, respectively. The JASPAR database was employed for predicting the binding site of GMEB1 with YAP1 promoter. Dual-luciferase reporter gene assay and chromatin immunoprecipitation-qPCR were conducted to verify the binding relationship of GMEB1 with YAP1 promoter region.

RESULTS

GMEB1 was up-regulated in HCC cells and tissues, and GMEB1 expression was correlated to the tumor size and TNM stage of HCC patients. GMEB1 overexpression facilitated HCC cell multiplication, migration, and invasion, and suppressed the apoptosis, whereas GMEB1 knockdown had the opposite effects. GMEB1 bound to YAP1 promoter region and positively regulated YAP1 expression in HCC cells.

CONCLUSION

GMEB1 facilitates HCC malignant proliferation and metastasis by promoting the transcription of the YAP1 promoter region.

Increased Platelet Distribution Width Predicts 3-Year Recurrence in Patients with Hepatocellular Carcinoma After Surgical Resection

Background

Platelet distribution width (PDW) is a marker of platelet anisocytosis that increases with platelet activation. The clinical implications of PDW in HCC are not well-defined. This study aimed to determine whether PDW could predict recurrence in patients with HCC after resection.

Methods

Between January and December 2008, 471 patients with HCC were recruited retrospectively. The clinicopathological characteristics of patients with HCC were analyzed based on the relationship between the two PDW groups. Kaplan-Meier curves and multivariate Cox regression analyses were used to evaluate the relationship between PDW and disease-free survival (DFS). A novel nomogram was developed based on the identified independent risk factors. Its accuracy was evaluated using a calibration curve and concordance index. The predictive value was evaluated using a receiver operating characteristic (ROC) curve.

Results

PDW was significantly associated with direct bilirubin, total bilirubin, urea, and prothrombin time. Patients with PDW ≥ 17.1 were a significantly shorter DFS than those with PDW < 17.1 (17.98% vs 49.83%, p< 0.001). Multivariate analysis determined that alpha-fetoprotein (AFP), carcinoembryonic antigen, microvascular invasion (MVI), tumor size, and tumor number were the independent variables associated with DFS. Patients with PDW ≥ 17.1 had a hazard ratio of 1.381 (95% confidence interval: 1.069-1.783, p = 0.014) for DFS. AFP, PDW, MVI, tumor size, and tumor number were identified as preoperative independent risk factors for DFS and used to establish the nomogram. Calibration curve analysis revealed that the standard curve fitted well with the predicted curve. ROC curve analysis demonstrated the high efficiency of the nomogram.

Conclusion

Increased PDW may predict recurrence-free survival in patients with HCC. Our nomogram model also performed well in predicting patient prognoses.

Comprehensive DNA methylation profiling of COVID-19 and hepatocellular carcinoma to identify common pathogenesis and potential therapeutic targets

BACKGROUND & AIMS

The effects of SARS-CoV-2 infection can be more complex and severe in patients with hepatocellular carcinoma (HCC) as compared to other cancers. This is due to several factors, including pre-existing conditions such as viral hepatitis and cirrhosis, which are commonly associated with HCC.

METHODS

We conducted an analysis of epigenomics in SARS-CoV-2 infection and HCC patients, and identified common pathogenic mechanisms using weighted gene co-expression network analysis (WGCNA) and other analyses. Hub genes were identified and analyzed using LASSO regression. Additionally, drug candidates and their binding modes to key macromolecular targets of COVID-19 were identified using molecular docking.

RESULTS

The epigenomic analysis of the relationship between SARS-CoV-2 infection and HCC patients revealed that the co-pathogenesis was closely linked to immune response, particularly T cell differentiation, regulation of T cell activation and monocyte differentiation. Further analysis indicated that CD4⁺ T cells and monocytes play essential roles in the immunoreaction triggered by both conditions. The expression levels of hub genes MYLK2, FAM83D, STC2, CCDC112, EPHX4 and MMP1 were strongly correlated with SARS-CoV-2 infection and the prognosis of HCC patients. In our study, mefloquine and thioridazine were identified as potential therapeutic agents for COVID-19 in combined with HCC.

CONCLUSIONS

In this research, we conducted an epigenomics analysis to identify common pathogenetic processes between SARS-CoV-2 infection and HCC patients, providing new insights into the pathogenesis and treatment of HCC patients infected with SARS-CoV-2.

MESP2 binds competitively to TCF4 to suppress gastric cancer progression by regulating the SKP2/p27 axis

Gastric cancer (GC) is a major cause of human deaths worldwide, and is notorious for its high incidence and mortality rates. Mesoderm Posterior Basic Helix-loop-helix (bHLH) transcription factor 2 (MESP2) acts as a transcription factor with a conserved bHLH domain. However, whether MESP2 contributes to tumorigenesis and its potential molecular mechanisms, remain unexplored. Noticeably, MESP2 expression levels are decreased in GC tissues and cell lines compared to those in normal tissue. Further, in vitro and in vivo experiments have confirmed that MESP2 overexpression suppresses GC cell growth, migration, and invasion, whereas MESP2 knockdown results in the exact opposite. Here, we present the first report that MESP2 binds to transcription factor 7-like 2 (TCF7L2/TCF4) to inhibit the activation of the TCF4/beta-catenin transcriptional complex, decrease the occupancy of the complex on the S-phase kinase Associated Protein 2 (SKP2) promoter, and promote p27 accumulation. MESP2 knockdown facilitated tumorigenesis, which was partially suppressed by SKP2 knockdown. Taken together, we conclude that MESP2 binds competitively to TCF4 to suppress GC progression by regulating the SKP2/p27 axis, thus offering a potential therapeutic strategy for future treatment.

SIX4 upregulates IDH1 and metabolic reprogramming to promote osteosarcoma progression

Metabolism reprogramming plays an important role in tumorigenesis and osteosarcoma metastasis. Sine oculis homeobox 4 (SIX4) is reported to be a key transcription factor that is involved in glycolysis reprogramming of cancer cells. However, the role of SIX4 in osteosarcoma progression remains unknown. The expression profile of SIX4 in OS was evaluated in surgery samples of osteosarcoma patients. Functional studies were performed in vitro and in vivo. We found that SIX4 is significantly overexpressed in osteosarcoma and related to the undesirable prognosis of osteosarcoma patients. SIX4 promotes progression of osteosarcoma via upregulating isocitrate dehydrogenase 1 (IDH1), which provides novel prognostic biomarkers and promising therapeutic targets for osteosarcoma patients.

The role of YAP1 in survival prediction, immune modulation, and drug response: A pan-cancer perspective

Introduction

Dysregulation of the Hippo signaling pathway has been implicated in multiple pathologies, including cancer, and YAP1 is the major effector of the pathway. In this study, we assessed the role of YAP1 in prognostic value, immunomodulation, and drug response from a pan-cancer perspective.

Methods

We compared YAP1 expression between normal and cancerous tissues and among different pathologic stages survival analysis and gene set enrichment analysis were performed. Additionally, we performed correlation analyses of YAP1 expression with RNA modification-related gene expression, tumor mutation burden (TMB), microsatellite instability (MSI), immune checkpoint regulator expression, and infiltration of immune cells. Correlations between YAP1 expression and IC50s (half-maximal inhibitory concentrations) of drugs in the CellMiner database were calculated.

Results

We found that YAP1 was aberrantly expressed in various cancer types and regulated by its DNA methylation and post-transcriptional modifications, particularly m6A methylation. High expression of YAP1 was associated with poor survival outcomes in ACC, BLCA, LGG, LUAD, and PAAD. YAP1 expression was negatively correlated with the infiltration of CD8+ T lymphocytes, CD4+ Th1 cells, T follicular helper cells, NKT cells, and activated NK cells, and positively correlated with the infiltration of myeloid-derived suppressor cells (MDSCs) and cancer-associated fibroblasts (CAFs) in pan-cancer. Higher YAP1 expression showed upregulation of TGF-β signaling, Hedgehog signaling, and KRAS signaling. IC50s of FDA-approved chemotherapeutic drugs capable of inhibiting DNA synthesis, including teniposide, dacarbazine, and doxorubicin, as well as inhibitors of hypoxia-inducible factor, MCL-1, ribonucleotide reductase, and FASN in clinical trials were negatively correlated with YAP1 expression.

Discussion

In conclusion, YAP1 is aberrantly expressed in various cancer types and regulated by its DNA methylation and post-transcriptional modifications. High expression of YAP1 is associated with poor survival outcomes in certain cancer types. YAP1 may promote tumor progression through immunosuppression, particularly by suppressing the infiltration of CD8+ T lymphocytes, CD4+ Th1 cells, T follicular helper cells, NKT cells, and activated NK cells, as well as recruiting MDSCs and CAFs in pan-cancer. The tumor-promoting activity of YAP1 is attributed to the activation of TGF-β, Hedgehog, and KRAS signaling pathways. AZD2858 and varlitinib might be effective in cancer patients with high YAP1 expression.

MEX3C-Mediated Decay of SOCS3 mRNA Promotes JAK2/STAT3 Signaling to Facilitate Metastasis in Hepatocellular Carcinoma

Tumor metastasis is one of the major causes of high mortality in patients with hepatocellular carcinoma (HCC). Sustained activation of STAT3 signaling plays a critical role in HCC metastasis. RNA binding protein (RBP)-mediated posttranscriptional regulation is involved in the precise control of signal transduction, including STAT3 signaling. In this study, we investigated whether RBPs are important regulators of HCC metastasis. The RBP MEX3C was found to be significantly upregulated in highly metastatic HCC and correlated with poor prognosis in HCC. Mechanistically, MEX3C increased JAK2/STAT3 pathway activity by downregulating SOCS3, a major negative regulator of JAK2/STAT3 signaling. MEX3C interacted with the 3'UTR of SOCS3 and recruited CNOT7 to ubiquitinate and accelerate decay of SOCS3 mRNA. Treatment with MEX3C-specific antisense oligonucleotide significantly inhibited JAK2/STAT3 pathway activation, suppressing HCC migration in vitro and metastasis in vivo. These findings highlight a novel mRNA decay-mediated mechanism for the disruption of SOCS3-driven negative regulation of JAK2/STAT3 signaling, suggesting MEX3C may be a potential prognostic biomarker and promising therapeutic target in HCC.

SIGNIFICANCE

This study reveals that RNA-binding protein MEX3C induces SOCS3 mRNA decay to promote JAK2/STAT3 activation and tumor metastasis in hepatocellular carcinoma, identifying MEX3C targeting as a potential approach for treating metastatic disease.

Comprehensive analysis of the potential role and prognostic value of sine oculis homeobox homolog family in colorectal cancer

BACKGROUND

Several genes, important for development, are reduced or silenced in adulthood, and their abnormal expression has been related to the occurrence and development of malignant tumors. Human sine oculis homeobox homolog (SIX) proteins belong to the homeobox family and play important roles in the development of different organs. Importantly, SIXs are predicted to have chromatin-binding and DNA-binding transcription factor activity with reported roles in cancers. However, a comprehensive analysis of SIXs in colorectal cancers (CRCs) has not been performed.

AIM

To explore the expression pattern of six SIX proteins in CRCs and their relationship with the clinicopathological parameters of CRC patients as well as investigate the potential utilization of SIXs as novel prognostic indicators in CRCs.

METHODS

The expression level of SIXs in normal tissues of different organs and related cancerous tissues was analyzed in the Human Protein Atlas. Kaplan-Meier Plotter and GEPIA2 were used to analyze the prognostic values of SIXs. To analyze the potential signaling pathways with SIX family involvement, LinkedOmics was used to perform Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses of SIX4-related genes. Subsequently, immunohistochemical experiments were performed on CRC tissues and adjacent normal tissues, and we examined the SIX4 expression level in 87 pairs of patients with tissue microarray. The relationship between SIX4 and clinicopathological parameters in CRC patients was tested using the χ² test and Fisher’s exact probability to verify the results of the database analysis.

RESULTS

The RNA levels of SIX1-4 and SIX6 were relatively low in normal human tissues, while SIX5 was highly expressed at both the RNA and protein levels. However, the protein level of SIX4 was found to be elevated in various malignancies. In CRC tissues, SIX1, SIX2 and SIX4 were elevated in cancer tissues compared with adjacent normal tissue. Among all SIXs, a high level of SIX4 was found to be associated with poor overall and disease-free survival in patients with CRC. For different clinicopathological parameters, increased SIX4 expression was positively correlated with advanced CRC. The top 50 SIX4-related genes were involved with oxidative phosphorylation and the respiratory chain signaling pathways.

CONCLUSION

The current results provided a comprehensive analysis of the expression and prognostic values of SIX family members in CRC. Among different SIXs, SIX4 plays an oncogenic role in CRC to promote the development of malignancy. In CRC, SIX4 mRNA and protein expression is higher than that in normal tissues and associated with shorter CRC patient survival, suggesting that SIX4 may be a potential therapeutic target for treatment of CRC patients.

SIX3 function in cancer: progression and comprehensive analysis

The homeobox gene family encodes transcription factors that are essential for cell growth, proliferation, and differentiation, and its dysfunction is linked to tumor initiation and progression. Sine oculis homeobox (SIX) belongs to the homeobox gene family, with SIX3 being a core member. Recent studies indicate that SXI3 functions as a cancer suppressor or promoter, which is mainly dependent on SIX3's influence on the signal pathways that promote or inhibit cancer in cells. The low expression of SIX3 in most malignant tumors was confirmed by detailed studies, which could promote the cell cycle, proliferation, migration, and angiogenesis. The recovery or upregulation of SIX3 expression to suppress cancer is closely related to the direct or indirect inhibition of the Wnt pathway. However, in some malignancies, such as esophageal cancer and gastric cancer, SIX3 is a tumor-promoting factor, and repressing SIX3 improves patients' prognosis. This review introduces the research progress of SIX3 in tumors and gives a comprehensive analysis, intending to explain why SIX3 plays different roles in different cancers and provide new cancer therapy strategies.

The overall process of metastasis: From initiation to a new tumor

Metastasis-a process that involves the migration of cells from the primary site to distant organs-is the leading cause of cancer-associated death. Improved technology and in-depth research on tumors have furthered our understanding of the various mechanisms involved in tumor metastasis. Metastasis is initiated by cancer cells of a specific phenotype, which migrate with the assistance of extracellular components and metastatic traits conferred via epigenetic regulation while modifying their behavior in response to the complex and dynamic human internal environment. In this review, we have summarized the general steps involved in tumor metastasis and their characteristics, incorporating recent studies and topical issues, including epithelial-mesenchymal transition, cancer stem cells, neutrophil extracellular traps, pre-metastatic niche, extracellular vesicles, and dormancy. Several feasible treatment directions have also been summarized. In addition, the correlation between cancer metastasis and lifestyle factors, such as obesity and circadian rhythm, has been illustrated.

A Novel and Robust Prognostic Model for Hepatocellular Carcinoma Based on Enhancer RNAs-Regulated Genes

Evidence has demonstrated that enhancer RNAs (eRNAs) play a vital role in the progression and prognosis of cancers, but few studies have focused on the prognostic ability of eRNA-regulated genes (eRGs) for hepatocellular carcinoma (HCC). Using gene expression profiles of HCC patients from the TCGA-LIHC and eRNA expression profiles from the enhancer RNA in cancers (eRic) data portal, we developed a novel and robust prognostic signature composed of 10 eRGs based on Lasso-penalized Cox regression analysis. According to the signature, HCC patients were stratified into high- and low-risk groups, which have been shown to have significant differences in tumor immune microenvironment, immune checkpoints, HLA-related genes, DNA damage repair-related genes, Gene-set variation analysis (GSVA), and the lower half-maximal inhibitory concentration (IC50) of Sorafenib. The prognostic nomogram combining the signature, age, and TNM stage had good predictive ability in the training set (TCGA-LIHC) with the concordance index (C-index) of 0.73 and the AUCs for 1-, 3-, and 5-year OS of 0.82, 0.77, 0.74, respectively. In external validation set (GSE14520), the nomogram also performed well with the C-index of 0.71 and the AUCs for 1-, 3-, and 5-year OS of 0.74, 0.77, 0.74, respectively. In addition, an important eRG (AKR1C3) was validated using two HCC cell lines (Huh7 and MHCC-LM3) in vitro, and the results demonstrated the overexpression of AKR1C3 is related to cell proliferation, migration, and invasion in HCC. Altogether, our eRGs signature and nomogram can predict prognosis accurately and conveniently, facilitate individualized treatment, and improve prognosis for HCC patients.

IGF2BP3‑stabilized SIX4 promotes the proliferation, migration, invasion and tube formation of ovarian cancer cells

The mortality rate of ovarian cancer (OC) is the highest among the different types of female reproductive system cancers. SIX homeobox 4 (SIX4), a member of the homeobox family, subfamily SIX, fulfills an important role in metastasis and angiogenesis in a variety of types of cancer. The aim of the present study was to investigate both the effects and the underlying mechanism of SIX4 on angiogenesis in OC. The Gene Expression Profiling Interactive Analysis and Encyclopedia of RNA Interactomes databases were employed to predict the expression levels of SIX4 in OC tissues, and its association with the overall survival (OS) rate of patients with OC. The expression levels of SIX4 in OC cell lines were detected by reverse transcription‑quantitative PCR (RT‑qPCR) and western blot analysis. Following silencing of SIX4, the proliferation, invasion, migration and angiogenesis of OC cells were investigated via Cell Counting Kit‑8, colony formation, wound healing, Transwell and tube formation assays. Subsequently, the levels of insulin‑like growth factor 2 mRNA binding protein 3 (IGF2BP3) in OC cell lines were detected by RT‑qPCR and western blot analysis. The ability of IGF2BP3 to bind to SIX4 mRNA was detected via an RNA immunoprecipitation assay, and the stability of SIX4 mRNA was assessed by RT‑qPCR following Actinomycin D treatment. Finally, the effects of transfection of sh‑SIX4 and overexpression of IGF2BP3 simultaneously were examined to further delineate the mechanism involved. It was revealed that SIX4 was highly expressed in OC tissues and cells, and its expression was associated with low OS rates in patients with OC. SIX4 knockdown with short hairpin RNA inhibited the proliferation, migration and invasion of cells, as well as angiogenesis. In addition, IGF2BP3 overexpression led to an improvement in the stability of SIX4 mRNA. Overexpression of IGF2BP3 also reversed the inhibitory effect of SIX4 interference on the malignant phenotypes of OC cells. Taken together, the results of the present study demonstrated that IGF2BP3‑stabilized SIX4 promoted the proliferation, metastasis and angiogenesis of SKOV3 cells.

FOXA1 Leads to Aberrant Expression of SIX4 Affecting Cervical Cancer Cell Growth and Chemoresistance

Cervical cancer (CC) is among the most prevalent cancers among female populations with high recurrence rates all over the world. Cisplatin (DDP) is the first-line treatment for multiple cancers, including CC. The main problem associated with its clinical application is drug resistance. This study is aimed at investigating the function and downstream regulation mechanism of forkhead-box A1 (FOXA1) in CC, which was verified as an oncogene in several cancers. Using GEO database and bioinformatics analysis, we identified FOXA1 as a possible oncogene in CC. Silencing of FOXA1 inhibited CC cell growth, invasion, and chemoresistance. Afterwards, the downstream gene of FOXA1 was predicted using a bioinformatics website and validated using ChIP and dual-luciferase assays. SIX4, a possible target of FOXA1, promoted CC cell malignant aggressiveness and chemoresistance. In addition, overexpression of SIX4 promoted phosphorylation of PI3K and AKT proteins and activated the PI3K/AKT signaling pathway. Further overexpression of SIX4 reversed the repressive effects of FOXA1 knockdown on CC cell growth, invasion, and chemoresistance in DDP-resistant cells. FOXA1-induced SIX4 facilitates CC progression and chemoresistance, highlighting a strong potential for FOXA1 to serve as a promising therapeutic target in CC.

T-box transcription factor 19 promotes hepatocellular carcinoma metastasis through upregulating EGFR and RAC1

The effect of targeted therapy for metastatic hepatocellular carcinoma (HCC) is still unsatisfactory. Exploring the underlying mechanism of HCC metastasis is favorable to provide new therapeutic strategies. T-box (TBX) transcription factor family genes, which are crucial regulators in embryo and organ development, are vital for regulating tumor initiation, growth and metastasis. Here we explored the role of TBX19 in HCC metastasis, which is one of the most upregulated TBX family genes in human HCC tissues. TBX19 expression was markedly upregulated in HCC tissues and elevated TBX19 expression predicted poor prognosis. Overexpression of TBX19 enhanced HCC metastasis through upregulating epidermal growth factor receptor (EGFR) and Rac family small GTPase 1 (RAC1) expression. Downregulation of EGFR and RAC1 inhibited TBX19-mediated HCC metastasis, while upregulation of EGFR and RAC1 restored inhibition of HCC metastasis mediated by TBX19 knockdown. Furthermore, epidermal growth factor (EGF)/EGFR signaling upregulated TBX19 expression via the extracellular signal-regulated kinase (ERK)/nuclear factor (NF)-kB axis. Besides, the combined application of EGFR inhibitor Erlotinib and RAC1 inhibitor NSC23766 markedly inhibited TBX19-mediated HCC metastasis. In HCC cohorts, TBX19 expression was positively associated with EGFR and RAC1 expression. Patients with positive coexpression of TBX19/EGFR or TBX19/RAC1 displayed the poorest prognosis. In conclusion, EGF/EGFR signaling upregulated TBX19 expression via ERK/NF-kB pathway and TBX19 fostered HCC metastasis by enhancing EGFR and RAC1 expression, which formed an EGF-TBX19-EGFR positive feedback loop. Targeting this signaling pathway may offer a potential therapeutic strategy to efficiently restrain TBX19-mediated HCC metastasis.

The feedback loop of ANKHD1/lncRNA MALAT1/YAP1 strengthens the radioresistance of CRC by activating YAP1/AKT signaling

Innate radioresistance substantially limits the effectiveness of radiotherapy for colorectal cancer (CRC); thus, a strategy to enhance the radiosensitivity of CRC is urgently needed. Herein, we reported that ankyrin repeat and KH domain containing 1 (ANKHD1) serves as a key regulator of radioresistance in CRC. ANKHD1 was highly expressed in CRC tissues and was highly correlated with Yes-associated protein 1 (YAP1) in CRC. Our results first revealed that ANKHD1 knockdown could increase the radiosensitivity of CRC by regulating DNA-damage repair, both in vitro and in vivo. Furthermore, the interactive regulation between ANKHD1 or YAP1 and lncRNA MALAT1 was revealed by RIP and RNA pull-down assays. Moreover, our results also demonstrated that MALAT1 silencing can radiosensitize CRC cells to IR through YAP1/AKT axis, similar to ANKHD1 silencing. Taken together, we report a feedback loop of ANKHD1/MALAT1/YAP1 that synergistically promotes the transcriptional coactivation of YAP1 and in turn enhances the radioresistance of CRC by regulating DNA-damage repair, probably via the YAP1/AKT axis. Our results suggested that targeting the YAP1/AKT axis downstream of ANKHD1/MALAT1/YAP1 may enhance the radiosensitivity of CRC.

Wnt/β-Catenin Signaling as a Driver of Hepatocellular Carcinoma Progression: An Emphasis on Molecular Pathways

Liver cancers cause a high rate of death worldwide and hepatocellular carcinoma (HCC) is considered as the most common primary liver cancer. HCC remains a challenging disease to treat. Wnt/β-catenin signaling pathway is considered a tumor-promoting factor in various cancers; hence, the present review focused on the role of Wnt signaling in HCC, and its association with progression and therapy response based on pre-clinical and clinical evidence. The nuclear translocation of β-catenin enhances expression level of genes such as c-Myc and MMPs in increasing cancer progression. The mutation of CTNNB1 gene encoding β-catenin and its overexpression can lead to HCC progression. β-catenin signaling enhances cancer stem cell features of HCC and promotes their growth rate. Furthermore, β-catenin prevents apoptosis in HCC cells and increases their migration via triggering EMT and upregulating MMP levels. It is suggested that β-catenin signaling participates in mediating drug resistance and immuno-resistance in HCC. Upstream mediators including ncRNAs can regulate β-catenin signaling in HCC. Anti-cancer agents inhibit β-catenin signaling and mediate its proteasomal degradation in HCC therapy. Furthermore, clinical studies have revealed the role of β-catenin and its gene mutation (CTNBB1) in HCC progression. Based on these subjects, future experiments can focus on developing novel therapeutics targeting Wnt/β-catenin signaling in HCC therapy.

The SIX Family of Transcription Factors: Common Themes Integrating Developmental and Cancer Biology

The sine oculis (SIX) family of transcription factors are key regulators of developmental processes during embryogenesis. Members of this family control gene expression to promote self-renewal of progenitor cell populations and govern mechanisms of cell differentiation. When the function of SIX genes becomes disrupted, distinct congenital defects develops both in animal models and humans. In addition to the embryonic setting, members of the SIX family have been found to be critical regulators of tumorigenesis, promoting cell proliferation, epithelial-to-mesenchymal transition, and metastasis. Research in both the fields of developmental biology and cancer research have provided an extensive understanding of SIX family transcription factor functions. Here we review recent progress in elucidating the role of SIX family genes in congenital disease as well as in the promotion of cancer. Common themes arise when comparing SIX transcription factor function during embryonic and cancer development. We highlight the complementary nature of these two fields and how knowledge in one area can open new aspects of experimentation in the other.

Selenium sulfide disrupts the PLAGL2/C-MET/STAT3-induced resistance against mitochondrial apoptosis in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Overexpression of pleomorphic adenoma gene like-2 (PLAGL2) is associated with tumorigenesis. However, its function in HCC is unclear, and there are currently no anti-HCC drugs that target PLAGL2. Drug repositioning may facilitate the development of PLAGL2-targeted drug candidates.

METHODS

The expression of PLAGL2 in HCC clinical tissue samples and HCC cell lines was analyzed by western blotting. The constructed HCC cell models were used to confirm the underlying function of PLAGL2 as a therapeutic target. Multiple in vitro and in vivo assays were conducted to determine the anti-proliferative and apoptosis-inducing effects of selenium sulfide (SeS2 ), which is clinically used for the treatment of seborrheic dermatitis and tinea versicolor.

RESULTS

PLAGL2 expression was higher in HCC tumor tissues than in normal adjacent tissues. Its overexpression promoted the resistance of HCC cells of mitochondrial apoptosis through the regulation of the downstream C-MET/STAT3 signaling axis. SeS2 exerted significant anti-proliferative and apoptosis-inducing effects on HCC cells in a PLAGL2-dependent manner. Mechanistically, SeS2 suppressed C-MET/STAT3, AKT/mTOR, and MAPK signaling and triggered Bcl-2/Cyto C/Caspase-mediated intrinsic mitochondrial apoptosis both in vitro and in vivo.

CONCLUSIONS

Our data reveal an important role of PLAGL2 in apoptosis resistance in HCC and highlight the potential of using SeS2 as a PLAGL2 inhibitor in patients with HCC.

Homeobox B5 promotes metastasis and poor prognosis in Hepatocellular Carcinoma, via FGFR4 and CXCL1 upregulation

Background: Since metastasis remains the main reason for HCC-associated death, a better understanding of molecular mechanism underlying HCC metastasis is urgently needed. Here, we elucidated the role of Homeobox B5 (HOXB5), a member of the HOX transcriptional factor family, in promoting HCC metastasis.

Method: The expression of HOXB5 and its functional targets fibroblast growth factor receptor 4 (FGFR4) and C-X-C motif chemokine ligand 1 (CXCL1) were detected by immunohistochemistry. Luciferase reporter and chromatin immunoprecipitation assays were performed to measure the transcriptional regulation of target genes by HOXB5. The effects of FGFR4 and CXCL1 on HOXB5-mediated metastasis were analyzed by an orthotopic metastasis model.

Results: Elevated expression of HOXB5 had a positive correlation with poor tumour differentiation, higher TNM stage, and indicated unfavorable prognosis. Overexpression of HOXB5 promoted HCC metastasis through transactivating FGFR4 and CXCL1 expression, whereas knockdown of FGFR4 and CXCL1 decreased HOXB5-enhanced HCC metastasis. Moreover, HOXB5 overexpression in HCC cells promoted myeloid derived suppressor cells (MDSCs) infiltration through CXCL1/CXCR2 axis. Either depletion of MDSCs by anti-Gr1 or blocking CXCL1-CXCR2 axis by CXCR2 inhibitor impaired HOXB5-mediated HCC metastasis. In addition, fibroblast growth factor 19 (FGF19) contributed to the HOXB5 upregulation through PI3K/AKT/HIF1α pathway. Overexpression of FGF15 (an analog of FGF19 in mouse) promoted HCC metastasis, whereas knockdown of HOXB5 significantly inhibited FGF15-enhanced HCC metastasis in immunocompetent mice. HOXB5 expression was positively associated with CXCL1 expression and intratumoral MDSCs accumulation in human HCC tissues. Patients who co-expressed HOXB5/CXCL1 or HOXB5/CD11b exhibited the worst prognosis. Furthermore, the combination of FGFR4 inhibitor BLU-554 and CXCR2 inhibitor SB265610 dramatically decreased HOXB5-mediated HCC metastasis.

Conclusion: HOXB5 was a potential prognostic biomarker in HCC patients and targeting this loop may provide a promising treatment strategy for the inhibition of HOXB5-mediated HCC metastasis.

MiR-21-3p Promotes Hepatocellular Carcinoma Progression via SMAD7/YAP1 Regulation

Background

Hepatocellular carcinoma (HCC) remains a major global health burden due to its high prevalence and mortality. Emerging evidence reveals that microRNA (miRNA) plays a vital role in cancer pathogenesis and is widely involved in the regulation of signaling pathways via their targeting of downstream genes. MiR-21-3p, a liver-enriched miRNA, and SMAD7, the negative regulator of the TGF-β signaling pathway, likely exert a vital influence on HCC progression.

Aims

Here, we explore the role of the miR-21-3p-SMAD7/YAP1 axis on HCC pathogenesis.

Methods

MiRNA microarray analysis was performed for miRNA screening. The dual-luciferase assay was adopted for target verification. Expression of miRNA and related genes were quantified via qRT-PCR, western blotting, and immunohistochemical staining. Flow cytometry and the transwell migration assay were used to detail cell apoptosis, invasion and metastases. Rat models were established to explore the role of the miR-21-3p-SMAD7/YAP1 axis in hepatocarcinogenesis. Bioinformatics analysis was conducted for exploring genes of clinical significance.

Results

MiR-21-3p levels were found to be significantly elevated in hepatocellular carcinoma and indicate poor overall survival. High miR-21-3p levels were associated with advanced tumor stages (P = 0.029), in particular T staging (P = 0.026). Low SMAD7/high YAP1 levels were confirmed in both HCC and rat models with advanced liver fibrosis and cirrhosis. Besides, SMAD7 was demonstrated to be the direct target of miR-21-3p. The effect of MiR-21-3p on tumor phenotypes and YAP1 upregulation could be partly reversed via the restoration of SMAD7 expression in HCC cell lines. Overexpression of YAP1 after miR-21-3p upregulation promoted expression of nuclear transcription effector connective tissue growth factor. Co-survival analysis indicated that lower miR-21-3p/higher SMAD7 (P = 0.0494) and lower miR-21-3p/lower YAP1 (P = 0.0379) group patients had better overall survival rates. Gene Set Variation Analysis revealed that gene sets related to miR-21-3p and SMAD7 were significantly associated with the TGF-β signaling pathway in HCC.

Conclusion

MiR-21-3p promotes migration and invasion of HCC cells and upregulation of YAP1 expression via direct inhibition of SMAD7, underscoring a major epigenetic mechanism in the pathogenesis of HCC.