Coordination of FOXA2 and SIRT6 suppresses the hepatocellular carcinoma progression through ZEB2 inhibition

Analysis of the Expression and Prognostic Value of SIRTs in Hepatocellular Carcinoma

Purpose

This study contributes to the evolving understanding of the pivotal involvement of Sirtuins (SIRTs) in various human cancers, with a particular focus on elucidating their expression patterns and clinical relevance within the context of hepatocellular carcinoma (HCC). The investigation involves a comprehensive analysis of mRNA expression and prognostic implications associated with distinct SIRTs in HCC.

Patients and Methods

Initial data pertaining to SIRT expression in HCC patients were collated from publicly accessible databases. Subsequently, the expression levels of select members of the SIRT family were validated using clinicopathological specimens from HCC patients. Additionally, HCC tissue microarray was employed to scrutinize the correlation between SIRT7 expression and HCC prognosis.

Results

The findings indicated a substantial upregulation of SIRT2, SIRT3, SIRT4, SIRT6, and SIRT7 in HCC tissues. Survival analysis underscored a pronounced association between elevated mRNA levels of SIRT3, SIRT6, and SIRT7 and an adverse prognosis for HCC patients. Particularly, SIRT7 emerged as a potential independent risk factor for poor prognosis in HCC patients. Examination of the HCC tissue microarray revealed heightened expression of SIRT7 in 68 cases (54.8%) of HCC tissues. Multivariate analysis established high SIRT7 expression as an independent risk factor for diminished Disease-Free Survival (DFS) and Overall Survival (OS) in HCC patients.

Conclusion

The aberrant expression of SIRT7 presents itself may be as a novel biomarker for predicting the prognosis of HCC patients.

FOXA2 suppresses gallbladder carcinoma cell migration, invasion, and epithelial-mesenchymal transition by targeting SERPINB5

BACKGROUND

Gallbladder cancer (GBC), a highly malignant gastrointestinal tumor, lacks effective therapies. Foxhead box A2 (FOXA2) is a tumor suppressor that is poorly expressed in various human malignancies. This study aimed to ascertain FOXA2 expression in GBC and its relevance to tumor metastasis, and to elucidate its regulatory mechanism with epithelial-mesenchymal transition (EMT) as an entry point, in the hope of providing a potential therapeutic target for GBC.

METHODS

FOXA2 expression in GBC tissues was first detected using immunohistochemistry (IHC), followed by correlation analysis with clinicopathological characteristics and survival prognosis. Subsequently, the effects of FOXA2 on GBC cell migration and invasion, as well as EMT induction, were evaluated by scratch, Transwell, RT-PCR, and Western blot assays, together with animal experimentation. Ultimately, mRNA sequencing was carried out to identify the key downstream target genes of FOXA2 in controlling the EMT process in GBC cells, and dual-luciferase reporter and chromatin immunoprecipitation assays were used to determine its regulatory mechanism.

RESULTS

FOXA2 was underexpressed in GBC tissues and inversely correlated with tumor node metastasis stage, lymph node metastasis, and poor patient prognosis. FOXA2 exerts suppressive effects on EMT and metastasis of GBC in vivo and in vitro. FOXA2 can impede GBC cell migratory and invasive functions and EMT by positively mediating serine protein kinase inhibitor B5 (SERPINB5) expression.

CONCLUSION

FOXA2 directly binds to the SERPINB5 promoter region to stimulate its transcription, thereby modulating the migration and invasion behaviors of GBC cells as well as the EMT process, which might be an effective therapeutic target against GBC.

MOF-mediated acetylation of SIRT6 disrupts SIRT6-FOXA2 interaction and represses SIRT6 tumor-suppressive function by upregulating ZEB2 in NSCLC

Mammalian sirtuin 6 (SIRT6) regulates a spectrum of vital biological processes and has long been implicated in the progression of cancer. However, the mechanisms underlying the regulation of SIRT6 in tumorigenesis remain elusive. Here, we report that the tumor-suppressive function of SIRT6 in non-small cell lung cancer (NSCLC) is regulated by acetylation. Specifically, males absent on the first (MOF) acetylates SIRT6 at K128, K160, and K267, resulting in a decreased deacetylase activity of SIRT6 and attenuated SIRT6 tumor-suppressive function in NSCLC. Mechanistically, MOF-mediated SIRT6 acetylation hinders the interaction between SIRT6 and transcriptional factor FOXA2, which in turn leads to the transcriptional activation of ZEB2, thus promoting NSCLC progression. Collectively, these data indicate an acetylation-dependent mechanism that modulates SIRT6 tumor-suppressive function in NSCLC. Our findings suggest that the MOF-SIRT6-ZEB2 axis may represent a promising therapeutic target for the management of NSCLC.

Harnessing function of EMT in hepatocellular carcinoma: From biological view to nanotechnological standpoint

Management of cancer metastasis has been associated with remarkable reduction in progression of cancer cells and improving survival rate of patients. Since 90% of mortality are due to cancer metastasis, its suppression can improve ability in cancer fighting. The EMT has been an underlying cause in increasing cancer migration and it is followed by mesenchymal transformation of epithelial cells. HCC is the predominant kind of liver tumor threatening life of many people around the world with poor prognosis. Increasing patient prognosis can be obtained via inhibiting tumor metastasis. HCC metastasis modulation by EMT and HCC therapy by nanoparticles are discussed here. First of all, EMT happens during progression and advanced stages of HCC and therefore, its inhibition can reduce tumor malignancy. Moreover, anti-cancer compounds including all-trans retinoic acid and plumbaging, among others, have been considered as inhibitors of EMT. The EMT association with chemoresistance has been evaluated. Moreover, ZEB1/2, TGF-β, Snail and Twist are EMT modulators in HCC and enhancing cancer invasion. Therefore, EMT mechanism and related molecular mechanisms in HCC are evaluated. The treatment of HCC has not been only emphasized on targeting molecular pathways with pharmacological compounds and since drugs have low bioavailability, their targeted delivery by nanoparticles promotes HCC elimination. Moreover, nanoparticle-mediated phototherapy impairs tumorigenesis in HCC by triggering cell death. Metastasis of HCC and even EMT mechanism can be suppressed by cargo-loaded nanoparticles.

Role of sirtuins in hepatocellular carcinoma progression and multidrug resistance: Mechanistical and pharmacological perspectives

Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer worldwide. Therapeutic strategies are still challenging due to the high relapse rate after surgery and multidrug resistance (MDR). It is essential to better understand the mechanisms for HCC progression and MDR for the development of new therapeutic strategies. Mammalian sirtuins (SIRTs), a family of seven members, are related to tumor progression, MDR and prognosis and were proposed as potential prognostic markers, as well as therapeutic targets for treating cancer. SIRT1 is the most studied member and is overexpressed in HCC, playing an oncogenic role and predicting poor prognosis. Several manuscripts describe the role of SIRTs2-7 in HCC; most of them report an oncogenic role for SIRT2 and -7 and a suppressive role for SIRT3 and -4. The scenario is more confusing for SIRT5 and -6, since information is contradictory and scarce. For SIRT1 many inhibitors are available and they seem to hold therapeutic promise in HCC. For the other members the development of specific modulators has just started. This review is aimed to describe the features of SIRTs1-7 in HCC, and the role they play in the onset and progression of the disease. Also, when possible, we will depict the information related to the SIRTs modulators that have been tested in HCC and their possible implication in MDR. With this, we hope to clarify the role of each member in HCC and to shed some light on the most successful strategies to overcome MDR.

The O-GlcNAcylation and its promotion to hepatocellular carcinoma

O-GlcNAcylation is a posttranslational modification that attaches O-linked β-N-acetylglucosamine (O-GlcNAc) to the serine and threonine residues of proteins. Such a glycosylation would alter the activities, stabilities, and interactions of target proteins that are functional in a wide range of biological processes and diseases. Accumulating evidence indicates that O-GlcNAcylation is tightly associated with hepatocellular carcinoma (HCC) in its onset, growth, invasion and metastasis, drug resistance, and stemness. Here we summarize the discoveries of the role of O-GlcNAcylation in HCC and its function mechanism, aiming to deepen our understanding of HCC pathology, generate more biomarkers for its diagnosis and prognosis, and offer novel molecular targets for its treatment.

Histone H3K9 methyltransferase SETDB1 augments invadopodia formation to promote tumor metastasis

Non-small cell lung cancer (NSCLC) is one of leading causes of cancer-related mortality worldwide, which harbors various accumulated genetic and epigenetic abnormalities. Histone methyltransferase SETDB1 is a pivotal epigenetic regulator whose focal amplification and upregulation are commonly detected in NSCLC. However, molecular mechanisms underlying the pro-oncogenic function of SETDB1 remain poorly characterized. Here, we demonstrate that SETDB1 augments the migration and invasion capabilities of NSCLC cells by reinforcing invadopodia formation and mediated ECM degradation. At the molecular level, SETDB1 suppresses the expression of FOXA2, a crucial tumor and metastasis suppressor via coordinated epigenetic mechanisms - SETDB1 not only catalyzes histone H3K9 methylation on FOXA2 genomic locus, but also recruits DNMT3A to regulate DNA methylation on CpG island. Consequently, depletion of Setdb1 in murine lung adenocarcinoma cells completely abolished their full and spontaneous metastatic capabilities in mouse xenograft models. These findings together establish the pro-metastasis activity of SETDB1 in NSCLC and elucidate the underlying cellular and molecular mechanisms.

Low APOA-1 Expression in Hepatocellular Carcinoma Patients Is Associated With DNA Methylation and Poor Overall Survival

Background: Hepatocellular carcinoma (HCC) is the most frequent fatal malignancy, and it has a poor prognosis. Apolipoprotein 1 (APOA-1), the main protein component of high-density lipoproteins, is involved in numerous biological processes. Thus, this study was performed to detect the clinical significance of APOA-1 mRNA, APOA-1 expression, and APOA-1DNA methylation in patients with HCC.

Methods: Data mining was performed using clinical and survival data from the Cancer Genome Atlas (TCGA) and Oncomine databases. The serum concentration of APOA-1 was measured in 316 patients with HCC and 100 healthy individuals at Renmin Hospital of Wuhan University, and the intact clinical information was reviewed and determined using univariate and multivariate Cox hazard models.

Results: Bioinformatic analysis revealed that APOA-1 mRNA was present at lower levels in the serum of patients with HCC than in that of healthy individuals, and there was a strong negative correlation between levels of APOA-1 mRNA and APOA-1 DNA methylation. High expression of APOA-1 transcription correlated with better overall survival (p = 0.003), and APOA-1 hypermethylation correlated with progress-free survival (p = 0.045) in HCC sufferers. Next, the clinical data analysis demonstrated that APOA-1 protein levels in the serum were significantly lower in patients with HCC than in healthy controls. Furthermore, the expression of APOA-1 was significantly associated with some significant clinical indexes, and elevated APOA-1 expression was significantly associated with favorable (OS; HR:1.693, 95% CI: 1.194–2.401, p = 0.003) and better progression-free survival (PFS; HR = 1.33, 95% CI = 1.194–2.401, p = 0.045). Finally, enrichment analysis suggested that co-expressed genes of APOA-1 were involved in lipoprotein metabolism and FOXA2/3 transcription factor networks.

Conclusion: APOA-1 mRNA expression is negatively regulated by DNA methylation in HCC. Low expression of APOA-1 might be a potential risk biomarker to predict survival in patients with HCC.

O-GlcNAcylation promotes the migratory ability of hepatocellular carcinoma cells via regulating FOXA2 stability and transcriptional activity

O-GlcNAcylation is a posttranslational modification that regulates numerous nuclear and cytoplasmic proteins and is emerging as a key regulator of various biological processes, such as transcription, signal transduction, and cell motility. Although increasing evidence has shown that elevated levels of global O-GlcNAcylation are linked to the metastasis in hepatocellular carcinoma (HCC) cells, the underlying mechanism is still ambiguous. In this study, we demonstrated that forkhead box protein A2 (FOXA2), an essential transcription factor for liver homeostasis and HCC developing, was O-GlcNAcylated by O-GlcNAc transferase (OGT) and regulates HCC cells migration and invasion. Opposite FOXA2 and OGT expression tendency were observed in HCC tissues, and lower FOXA2 levels predicted a poor prognosis in HCC patients. The reduction of FOXA2 in HCC cells was found to be inversely correlated with the cellular O-GlcNAcylation and cell migratory ability. Notably, we found that FOXA2 was modified by O-GlcNAcylation and that O-GlcNAcylation activated the ubiquitination degradation of FOXA2 in highly metastatic HCC cells. Although this modification did not affect FOXA2 nuclear localization capability, O-GlcNAcylation on FOXA2 was key for attenuating FOXA2-mediated transcription. O-GlcNAcylation decreased the transcription of FOXA2 downstream target gene E-cadherin and it ultimately promoted O-GlcNAcylation-mediated HCC cell migration and invasion. The results provide insights into the role of O-GlcNAcylation in regulating FOXA2 activity and suggest its important implications in HCC metastasis.

Emerging roles of SIRT6 in human diseases and its modulators

The biological functions of sirtuin 6 (SIRT6; e.g., deacetylation, defatty-acylation, and mono-ADP-ribosylation) play a pivotal role in regulating lifespan and several fundamental processes controlling aging such as DNA repair, gene expression, and telomeric maintenance. Over the past decades, the aberration of SIRT6 has been extensively observed in diverse life-threatening human diseases. In this comprehensive review, we summarize the critical roles of SIRT6 in the onset and progression of human diseases including cancer, inflammation, diabetes, steatohepatitis, arthritis, cardiovascular diseases, neurodegenerative diseases, viral infections, renal and corneal injuries, as well as the elucidation of the related signaling pathways. Moreover, we discuss the advances in the development of small molecule SIRT6 modulators including activators and inhibitors as well as their pharmacological profiles toward potential therapeutics for SIRT6-mediated diseases.

Prognostic role of SIRT6 in gastrointestinal cancers: a meta-analysis

Sirtuin 6 (SIRT6) plays a critical role in the progression and development of gastrointestinal cancers. However, the association between SIRT6 expression and clinicopathological parameters and prognosis in gastrointestinal cancer patients remains inconclusive. Consequently, we conducted this meta-analysis to evaluate the importance of SIRT6 expression in various types of gastrointestinal cancers. PubMed, EMBASE, and Web of Science databases were systematically searched to screen the relevant literature. The reported or estimated hazard ratio (HR) and odds ratio (OR) and their corresponding 95% confidence interval (CI) were pooled to assess the strength of the association. Nine studies involving 867 patients were included in the meta-analysis. Overall analysis showed that high SIRT6 expression was related to better overall survival in gastrointestinal cancers (HR = 0.62, 95% CI = 0.47–0.82). High SIRT6 expression was also related to a favorable tumor node metastasis (TNM) stage (OR = 0.44, 95% CI = 0.28–0.70) among gastrointestinal cancer patients. Our meta-analysis revealed that high SIRT6 expression might be a potential biomarker predicting better prognosis in gastrointestinal cancers, which may offer options for gastrointestinal cancer treatment.

FOX transcription factor family in hepatocellular carcinoma

The pathogenesis of hepatocellular carcinoma (HCC) is a multistep process, involving the progressive accumulation of molecular alterations and transcriptomic alterations. The Forkhead-box (FOX) transcription factor family is characterized by its unique DNA binding domain (FKH or winged-helix domain). Human FOX family consists of about 17 subfamilies, at least 43 members. Some of them are liver-enriched transcription factors, suggesting that they may play a crucial role in the development or/and functions of the liver. Dysregulation of FOX transcription factors may contribute to the pathogenesis of HCC because they can activate or suppress the expression of various tumor-related molecules, and pinpoint different molecular and cellular events. Here we summarized, analyzed and discussed the status and the functions of the human FOX family of transcription factors in HCC, aiming to help the further development of them as potential therapeutic targets or/and diagnostic/prognostic markers for HCC.

Sirtuin6 (SIRT6) Promotes the EMT of Hepatocellular Carcinoma by Stimulating Autophagic Degradation of E-Cadherin

EMT is a pivotal mechanism involved in tumor metastasis, which is the leading cause of poor prognosis for hepatocellular carcinoma (HCC). Sirtuin family members function as NAD⁺-dependent deacetylases that are essential for tumor metastasis and epithelial-mesenchymal transition (EMT). However, no causal association has been established between Sirtuin6 (SIRT6) and HCC metastasis. SIRT6 expression pattern and its association with HCC metastasis were investigated by informatic analysis, and verified by qRT-PCR and immunochemistry in HCC tissues. Transwell assay, qRT-PCR, and immunofluorescence assay were utilized to assess the effects of SIRT6 on metastasis and E-cadherin expression in vitro and in vivo. Immunoprecipitation assay was performed to observe whether SIRT6 deacetylated Beclin-1 in HCC cells. Immunofluorescence assay and inhibitor treatment rescue experiments were used to clarify the mechanism by which SIRT6 facilitated EMT and metastasis. SIRT6 upregulation was quite prevalent in HCC tissues and closely correlated with worse overall survival, disease-relapse free survival, and HCC metastasis. Furthermore, SIRT6 promoted HCC cell migration, invasion, and EMT. Mechanistically, we found that SIRT6 deacetylated Beclin-1 in HCC cells and this event led to the promotion of the autophagic degradation of E-cadherin. Noticeably, E-cadherin degradation and invasion, migration induced by SIRT6 overexpression could be rescued by dual mutation of Beclin-1 (inhibition of acetylation), CQ (autophagy inhibitor), and knockdown of Atg7. In addition, SIRT6 promoted N-cadherin and Vimentin expression via deacetylating FOXO3a in HCC. These results established a relationship between SIRT6 and HCC EMT and further elucidated the mechanisms underlying HCC metastasis, helping provide a promising approach for the treatment of HCC. IMPLICATIONS: Inhibiting SIRT6 represents a potential therapeutic approach to suppress HCC metastasis partially through reduction of autophagic degradation of E-cadherin.

Silencing of hsa_circ_0004771 inhibits proliferation and induces apoptosis in breast cancer through activation of miR-653 by targeting ZEB2 signaling pathway

Background: Circular RNAs (circRNAs) have been reported as the competing endogenous RNAs (ceRNAs) to sponge microRNAs (miRNAs) implicating in the initiation and progression of breast cancer. However, the functions of circRNAs in breast cancer have not been completely clarified. In the present study, we aimed to identify differentially expressed circRNAs in breast cancer tumor tissues, and their roles and downstream targets were investigated in the progression of breast cancer. Methods: High-throughput circRNA sequencing was performed to detect the differentially expressed circRNAs. The CCK-8 and flow cytometry were performed to measure the cell viability and apoptosis in breast cancer cells. Gene and protein expression were assayed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. Results: hsa_circ_0004771 and Zinc finger E-box binding homeobox 2 (ZEB2) expression levels were up-regulated and positively correlated in breast cancer tumor tissues. In addition, the expression levels of miR-653 were reduced in breast cancer tumor tissues. We also found that hsa_circ_0004771 functioned as a sponge of miR-653 to inhibit its expression. miR-653 as a post-transcriptional regulator down-regulated the expression of ZEB2 by binding to its 3′-UTR. Interestingly, a significant inverse correlation was observed between miR-653 and hsa_circ_0004771 or ZEB2 expression in breast cancer tumor tissues. Knockdown of hsa_circ_0004771 and ZEB2 served as equally authentic of miR-653 mimics to induce growth inhibition and apoptosis in breast cancer cells. Conclusion: Hsa_circ_0004771/miR-653/ZEB2 regulatory feedback revealed a new molecular mechanism in the pathogenesis of breast cancer, which might provide novel therapeutic targets for the treatment of breast cancer.