Hypoxia-induced up-regulation of VASP promotes invasiveness and metastasis of hepatocellular carcinoma

Targeting the lncRNA FGD5-AS1/miR-497-5p/PD-L1 Axis Inhibits Malignant Phenotypes in Colon Cancer (CC)

Long noncoding RNAs (lncRNAs) regulate cancer progression and drug resistance. However, the role of lncRNA FGD5-AS1 in regulating colon cancer (CC) progression is still largely unknown. Hence, this study investigated the role of lncRNA FGD5-AS1 in regulating colon cancer (CC) progression and found that lncRNA FGD5-AS1 regulated miR-497-5p/PD-L1 axis to promote cancer progression in CC cells in vitro and in vivo. Specifically, we found that lncRNA FGD5-AS1 and PD-L1 tended to be high-expressed, while miR-497-5p was low-expressed in CC tissues and cell lines compared to the normal adjacent tissues and cells. Next, we found that lncRNA FGD5-AS1 positively regulated PD-L1 in CC cells by sponging miR-497-5p. Finally, our gain- and loss-of-function experiments evidenced that the lncRNA FGD5-AS1/miR-497-5p/PD-L1 axis regulates CC progression. Functionally, the data suggested that lncRNA FGD5-AS1 positively regulated while miR-497-5p negatively modulated malignant phenotypes, including cell proliferation, viability, invasion, migration, epithelial-mesenchymal transition (EMT), and tumorigenesis in CC cells. Interestingly, the inhibiting effects of lncRNA FGD5-AS1 ablation on CC development were abrogated by both silencing miR-497-5p and upregulating PD-L1. This study found that lncRNA FGD5-AS1 sponged miR-497-5p to upregulate PD-L1, resulting in CC progression, and provided novel agents for CC diagnosis and prognosis.

Matrix stiffness-induced upregulation of histone acetyltransferase KAT6A promotes hepatocellular carcinoma progression through regulating SOX2 expression

BACKGROUND

Lysine acetyltransferase 6 A (KAT6A) is a MYST-type histone acetyltransferase (HAT) enzyme, which contributes to histone modification and cancer development. However, its biological functions and molecular mechanisms, which respect to hepatocellular carcinoma (HCC), are still largely unknown.

METHODS

Immunohistochemical, western blot and qRT-PCR analysis of KAT6A were performed. A series of in vitro and in vivo experiments were conducted to reveal the role of KAT6A in the progression of HCC.

RESULTS

We demonstrated that KAT6A expression was upregulated in HCC tissues and cell lines. Clinical analysis showed that increased KAT6A was significantly associated with malignant prognostic features and shorter survival. Gain- and loss-of-function experiments indicated that KAT6A promoted cell viability, proliferation and colony formation of HCC cells in vitro and in vivo. We confirmed that KAT6A acetylates lysine 23 of histone H3 (H3K23), and then enhances the association of the nuclear receptor binding protein TRIM24 and H3K23ac. Consequently, TRIM24 functions as a transcriptional activator to activate SOX2 transcription and expression, leading to HCC tumorigenesis. Restoration of SOX2 at least partially abolished the biological effects of KAT6A on HCC cells. Overexpression of KAT6A acetyltransferase activity-deficient mutants or TRIM24 mutants lacking H3K23ac binding sites did not affect SOX2 expression and HCC biological function. Moreover, matrix stiffness can upregulate the expression of KAT6A in HCC cells.

CONCLUSIONS

Our data support the first evidence that KAT6A plays an oncogenic role in HCC through H3K23ac/TRIM24-SOX2 pathway, and represents a promising therapeutic strategy for HCC patients.

Hypoxia‑inducible factor‑1α: A critical target for inhibiting the metastasis of hepatocellular carcinoma (Review)

Metastasis is one of the major reasons for patient mortality in hepatocellular carcinoma (HCC), and the progression of HCC to a metastatic state depends on the local microenvironment. Hypoxia is a key condition affecting the microenvironment of HCC. Currently, various studies have shown that the expression of hypoxia-ainducible factor-1α (HIF-1α) is associated with the invasion and metastasis of HCC. High expression of HIF-1α often leads to poor prognosis in patients with HCC. In this review, the molecular structure of HIF-1α is described, and the expression pattern of HIF-1α in HCC under hypoxia, which is associated with metastasis and poor prognosis in HCC, is explained. The molecular mechanisms of HIF-1α function and the metastasis of HCC are further discussed. The modulation of HIF-1α can reduce sorafenib resistance and improve the prognosis of patients after TACE. Therefore, HIF-1α may be a critical target for inhibiting HCC metastasis in the future.

HIF-1/2α-Activated RNF146 Enhances the Proliferation and Glycolysis of Hepatocellular Carcinoma Cells via the PTEN/AKT/mTOR Pathway

Hypoxia microenvironment, a critical feature of hepatocellular carcinoma, contributes to hepatocarcinogenesis, tumor progression and therapeutic resistance. Hypoxia-inducible factors (HIFs)-activated target genes are the main effectors in hypoxia-induced HCC progression. In this study, we identified ubiquitin E3 ligase ring finger protein 146 (RNF146) as a novel HIFs target gene. Either HIF-1α or HIF-2α knockdown significantly repressed hypoxia-induced RNF146 upregulation in Hep3B and Huh7 cells. TCGA data and our immunohistochemistry analysis consistently revealed the overexpression of RNF146 in HCC tissues. The upregulated expression of RNF146 was also detected in HCC cell lines. The high RNF146 level was correlated with poor clinical features and predicted a shorter overall survival of patients with HCC. RNF146 knockdown suppressed the proliferation, colony formation and glycolysis of HCC cells, but suppressed but RNF146 overexpression promoted these malignant behaviors. Moreover, RNF146 silencing weakened HCC growth in mice. RNF146 inversely regulated phosphatase and tensin homolog (PTEN) protein level, thereby activating the AKT/mechanistic target of rapamycin kinase (mTOR) pathway in HCC cells. MG132 reversed RNF146 overexpression-induced PTEN reduction. RNF146 knockdown decreased the ubiquitination and degradation of PTEN in HCC cells. Therefore, we clarified that PTEN knockdown notably abolished the effects of RNF146 silencing on the AKT/mTOR pathway and Hep3B cells’ proliferation, colony formation and glycolysis. To conclude, our data confirmed that RNF146 was transcriptionally regulated by HIF-1/2α and activated the AKT/mTOR pathway by promoting the ubiquitin proteolysis of PTEN, thereby contributing to HCC progression. RNF146 may be a potential new drug target for anti-HCC.

Sirtuins and Hypoxia in EMT Control

Epithelial–mesenchymal transition (EMT), a physiological process during embryogenesis, can become pathological in the presence of different driving forces. Reduced oxygen tension or hypoxia is one of these forces, triggering a large number of molecular pathways with aberrant EMT induction, resulting in cancer and fibrosis onset. Both hypoxia-induced factors, HIF-1α and HIF-2α, act as master transcription factors implicated in EMT. On the other hand, hypoxia-dependent HIF-independent EMT has also been described. Recently, a new class of seven proteins with deacylase activity, called sirtuins, have been implicated in the control of both hypoxia responses, HIF-1α and HIF-2α activation, as well as EMT induction. Intriguingly, different sirtuins have different effects on hypoxia and EMT, acting as either activators or inhibitors, depending on the tissue and cell type. Interestingly, sirtuins and HIF can be activated or inhibited with natural or synthetic molecules. Moreover, recent studies have shown that these natural or synthetic molecules can be better conveyed using nanoparticles, representing a valid strategy for EMT modulation. The following review, by detailing the aspects listed above, summarizes the interplay between hypoxia, sirtuins, and EMT, as well as the possible strategies to modulate them by using a nanoparticle-based approach.

Hypoxia-induced LncRNA DACT3-AS1 upregulates PKM2 to promote metastasis in hepatocellular carcinoma through the HDAC2/FOXA3 pathway

Growing evidence has revealed that hypoxia is involved in multiple stages of cancer development. However, there are limited reports on the effects of long noncoding RNAs (lncRNAs) on hepatocellular carcinoma (HCC) progression under hypoxia. The main purposes of this study were to analyze the effect of the novel lncRNA DACT3-AS1 on metastasis in HCC and to elucidate the related molecular mechanism. Bioinformatics tools were employed. RT–qPCR or western blot assays were conducted to detect RNA or protein expression. Clinical samples and in vivo assays were utilized to reveal the role of DACT3-AS1 in HCC. Other mechanism and functional analyses were specifically designed and performed as well. Based on the collected data, this study revealed that HIF-1α transcriptionally activates DACT3-AS1 expression under hypoxia. DACT3-AS1 was verified to promote metastasis in HCC. Mechanistically, DACT3-AS1 promotes the interaction between HDAC2 and FOXA3 to stimulate FOXA3 deacetylation, which consequently downregulates the FOXA3 protein. Furthermore, FOXA3 serves as a transcription factor that can bind to the PKM2 promoter region, thus hindering PKM2 expression. To summarize, this study uncovered that HIF-1α-induced DACT3-AS1 promotes metastasis in HCC and can upregulate PKM2 via the HDAC2/FOXA3 pathway in HCC cells.

Understanding the role of an RNA molecule involved in metastasis (spread) of liver cancer may suggest potential therapeutic targets. Hepatocarcinoma is a common primary liver cancer, and mortality remains high due to late diagnosis and the risk of metastasis. Scientists believe hypoxic (low oxygen) conditions in solid tumors may trigger metastasis by a mechanism involving long non-coding RNAs. Bin Li and co-workers at the Affiliated Hospital of Guilin Medical College, China, used patient tissue samples to examine the role of the long non-coding RNA molecule DACT3-AS1 in promoting hepatocarcinoma metastasis. Hypoxia triggers the overexpression of HIF-1α. This protein activated DACT3-AS1, which was then highly expressed in metastatic tissues. DACT3-AS1 interacted with a nearby gene and associated enzyme to promote cell migration and invasion, hinting at possible treatment options.

A novel hypoxia-driven gene signature that can predict the prognosis of hepatocellular carcinoma

Hypoxia environment exists in already started hepatocellular carcinoma (HCC) and promotes its progression by driving changes in the gene expression profiles of cells. However, the status of hypoxia-driven genes in HCC is largely unknown. In the present study, 368 HCC tissues from The Cancer Genome Atlas were divided into high and low hypoxia groups according to their hypoxia signatures. A total of 1,142 differentially expressed genes (DEGs) were identified between the two groups, and 34 of these DEGs were highly expressed in HCC tissues compared with adjacent tissues, especially in HCC tissues from patients with stage III-IV HCC. After constructing a protein-protein interaction network and applying the least absolute shrinkage and selection operator Cox regression method for 34 DEGs, a three-gene signature (complement factor H related 3 [CFHR3], egl-9 family hypoxia inducible factor 3 [EGLN3], and chromogranin A [CHGA]) was constructed and had prognostic value to predicted outcome of patients with HCC. This three-gene signature was suitable for classifying patients with HCC in the International Cancer Genome Consortium. CFHR3 shows remarkable diagnostic value in HCC. Hypoxia decreased CFHR3 expression, but increased HCC cell proliferation and motility. Overexpression of CFHR3 in HCC cells under hypoxia reversed the stimulatory effects of hypoxia and suppressed cell proliferation and metastasis in vivo. In conclusion, we identified a novel hypoxia-driven gene signature (CFHR3, EGLN3, and CHGA) for reliable prognostic prediction of HCC, and demonstrated that overexpression of CFHR3 may be a potential strategy to overcome hypoxia and treat HCC.

Comprehensive analysis of the correlations of S100B with hypoxia response and immune infiltration in hepatocellular carcinoma

S100B has been found to be dysregulated in many cancers including hepatocellular carcinoma (HCC). However, the functions of S100B and its underlying mechanisms in HCC remain poorly understood, especially in the tumor microenvironment. In this study, functions enrichment analysis indicated that S100B expression was correlated with hypoxia and immune responses. We found that hypoxia could induce S100B expression in an HIF-1α-dependent manner in HepG2 cells. Luciferase reporter and ChIP-qRCR assays demonstrated that HIF-1α regulates S100B transcription by directly binding to hypoxia-response elements (HREs) of the S100B promoter. Functionally, knockdown of S100B reduces hypoxia-induced HepG2 cell invasion and migration. Furthermore, GSVA enrichment results displayed that S100B and its co-expressed genes were positively correlated with EMT pathway in HCC. Additionally, GO/KEGG cluster analysis results indicated that co-expressed genes of S100B were involved in biological processes of immune response and multiple tumor immune-related signaling pathways in HCC. S100B expression was positively correlated with multiple immune cells tumor infiltration and associated with chemokines/chemokine receptors and immune checkpoint genes. Moreover, S100B is predominantly expressed in immune cells, especially NK (Natural Killer) cell. In addition, the hub genes of S100B co-expression and hypoxia response in HepG2 cell were also associated with immune cells infiltration in HCC. Taken together, these findings provide a new insight into the complex networks between hypoxia response and immune cells infiltration in tumor microenvironment of liver cancer. S100B maybe serve as a novel target for future HCC therapies.

Modifications to the Transwell Migration/Invasion Assay Method That Eases Assay Performance and Improves the Accuracy

Migration is a key property of live cells and critical for normal development, immune response, and disease processes such as cancer metastasis and inflammation. Methods to examine cell migration are especially useful and important for a wide range of biomedical research such as cancer biology, immunology, vascular biology, cell biology, and developmental biology. In vitro assays are excellent approaches to extrapolate to in vivo situations and study live cells behavior. The aim of this article is to discuss the existing methods for transwell migration/invasion studies, the problems associated with this assay, and proposed modifications to this methodological approach that makes it simple to perform and improve the assay accuracy. Results of our studies demonstrated that the count of cells that had grown on top of the membrane is important to accurately evaluate the percentage of migrated/invaded cells. The results also showed that the transparent transwell insert with 4',6-diamidino-2-phenylindole (DAPI) stained cells is the best approach to ease the analysis of cell numbers on top of the membranes. In addition, the overlay of bright light (representing membrane pores) and DAPI images can further improve the accuracy of cell count. All these modifications in combination simplify the assay performance and improve the accuracy of the transwell migration assay method.

Transcriptional activation of S100A2 expression by HIF-1α via binding to the hypomethylated hypoxia response elements in HCC cells

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers. Dysregulation of S100A2 has recently been found in many cancers including HCC. However, its regulatory mechanism in HCC remains poorly understood, especially in hypoxia. In this study, we found that S100A2 is upregulated and correlated with the clinicopathological features of HCC patients. Moreover, the elevated S100A2 showed worse overall survival. Functionally, S100A2 inhibition decreased the proliferation and migration of HepG2 cells. Interestingly, we found that HIF-1α directly binds to hypoxia response elements (HREs) of the S100A2 promoter region. S100A2 expression could be induced in an HIF-1α-dependent manner under hypoxia. Furthermore, S100A2 silencing significantly suppressed HCC cell proliferation and invasion under hypoxia. Mechanistically, pyrosequencing results showed that the hypomethylation status of CpG located in the HRE at the S100A2 promoter was correlated with S100A2 induction. Additionally, HIF-1α- mediated S100A2 activation was associated with TET2-related epigenetic inactivation. TET2 was enriched in the HRE of the S100A2 promoter in HepG2 cells. Finally, S100A2 methylation-related genes and pathways were analyzed. We found that the methylation of S100A2 is correlated with ANXA2, PPP1R15A, and FOS, which include in a hypoxia-related gene set from the GSEA database. Moreover, some EMT-related genes are associated with the methylation of S100A2 in HCC. Conclusively, our study thus uncovered a novel mechanism showing that hypoxia/HIF-1α signaling associated with DNA methylation enhances S100A2 expression in HCC. S100A2 may be useful as a target for facilitating novel diagnostic and therapeutic strategies in liver cancer.

HIF-1α-activated long non-coding RNA KDM4A-AS1 promotes hepatocellular carcinoma progression via the miR-411-5p/KPNA2/AKT pathway

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with poor clinical outcomes. Long non-coding RNAs (lncRNAs) are extensively involved in the tumorigenesis and progression of HCC. However, more investigations should be carried out on novel lncRNAs and their effects on HCC. Here we identified a novel lncRNA KDM4A-AS1, which was aberrantly overexpressed in HCC tissues, associated with unfavorable clinical features and poor prognosis of patients. KDM4A-AS1 promoted HCC cell proliferation, migration, and invasion in vitro and contributed to HCC growth and lung metastasis in vivo. Mechanistically, KDM4A-AS1 was inversely modulated by miR-411-5p at the post-transcriptional level and facilitated Karyopherin α2 (KPNA2) expression by competitively binding miR-411-5p, thereby activating the AKT pathway. KPNA2 silencing, miR-411-5p overexpression, and AKT inhibitor (MK2206) consistently reversed KDM4A-AS1-enhanced proliferation, mobility, and EMT of HCC cells. KDM4A-AS1 was identified as a novel hypoxia-responsive gene and transactivated by hypoxia-inducible factor 1α (HIF-1α) in HCC cells. In turn, KDM4A-AS1 regulated HIF-1α expression through the KPNA2/AKT signaling pathway. Hence, this study revealed a novel hypoxia-responsive lncRNA, KDM4A-AS1, which contributed to HCC growth and metastasis via the KDM4A-AS1/KPNA2/HIF-1α signaling loop. Our findings provide a promising prognostic and therapeutic target for HCC.

Identification of AGT and CD44 in methotrexate-resistant colorectal cancer and reversal of methotrexate-resistance

This study aims to screen out hub genes in 2 methotrexate-resistant colorectal cancer (CRC) cells (HT29 and Caco2), compared with parental CRC cells and reverse methotrexate-resistance in methotrexate-resistant CRC. GEO database and R software were utilized to analyze the gene expression profiles GSE11440 and GSE16066. Venn diagram was used to identify intersection differentially expressed genes (DEGs) between GSE11440 and GSE16066. Protein-protein interaction (PPI) was utilized to screen out central node genes. Hub genes were determined by volcano graphs, heatmaps and box plots. The functional enrichment analysis was exhibited with DAVID. The GEPIA was used to obtain survival curves to analyze association between patient prognosis and hub genes. Western blotting was used to detect the expressions of hub genes. CCK-8 assay was used to show MTX-resistant CRC cell viability following CD44 inhibitor (THIQ) and AGT inhibitor (O⁶-BG) treatments. In our results, there were 180 intersection DEGs between GSE11440 and GSE16066. CD44 and AGT were screened out as hub genes by PPI, heatmaps, volcano and box plots. In the 2 MTX-resistant CRC cells, the expressions of CD44 and AGT were up-regulated compared with parental CRC cells. The results of western blotting showed that CD44 and AGT were up-regulated in MTX-resistant HT29 and Caco2 cells compared with parental CRC cells. CCK-8 assay results showed that the combination of MTX with O⁶-BG or THIQ could significantly reduce the activity of MTX-resistant CRC cells. This research screened out CD44 and AGT in MTX-resistant CRC cells by bioinformatics and suggested that the combination of MTX with O⁶-BG or THIQ could enhance the sensitivity of MTX-resistant CRC cells to MTX. This research provides a new strategy for overcoming MTX-resistance in CRC.

ONECUT2 facilitates hepatocellular carcinoma metastasis by transcriptionally upregulating FGF2 and ACLY

Metastasis is the predominant reason for high mortality of hepatocellular carcinoma (HCC) patients. It is critical to explore the molecular mechanism underlying HCC metastasis. Here, we reported that transcription factor One Cut homeobox 2 (ONECUT2) functioned as an oncogene to facilitate HCC metastasis. Elevated ONECUT2 expression was positively correlated with increased tumor number, tumor encapsulation loss, microvascular invasion, poor tumor differentiation, and advanced TNM stage. Mechanistically, ONECUT2 directly bound to the promoters of fibroblast growth factor 2 (FGF2) and ATP citrate lyase (ACLY) and transcriptionally upregulated their expression. Knockdown of FGF2 and ACLY inhibited ONECUT2-mediated HCC metastasis, whereas upregulation of FGF2 and ACLY rescued ONECUT2 knockdown-induced suppression of HCC metastasis. ONECUT2 expression was positively correlated with FGF2 and ACLY expression in human HCC tissues. HCC patients with positive coexpression of ONECUT2/FGF2 or ONECUT2/ACLY exhibited the worst prognosis. In addition, FGF2 upregulated ONECUT2 expression through the FGFR1/ERK/ELK1 pathway, which formed an FGF2-FGFR1-ONECUT2 positive feedback loop. Knockdown of ONECUT2 inhibited FGF2-induced HCC metastasis. Furthermore, the combination of FGFR1 inhibitor PD173074 with ACLY inhibitor ETC-1002 markedly suppressed ONECUT2-mediated HCC metastasis. In summary, ONECUT2 was a potential prognostic biomarker in HCC and targeting this oncogenic signaling pathway may provide an efficient therapeutic strategy against HCC metastasis.

CCL4 Stimulates Cell Migration in Human Osteosarcoma via the mir-3927-3p/Integrin αvβ3 Axis

Osteosarcoma is the most common type of primary malignant bone cancer, and it is associated with high rates of pulmonary metastasis. Integrin αvβ3 is critical for osteosarcoma cell migratory and invasive abilities. Chemokine (C-C motif) ligand 4 (CCL4) has diverse effects on different cancer cells through its interaction with its specific receptor, C-C chemokine receptor type 5 (CCR5). Analysis of mRNA expression in human osteosarcoma tissue identified upregulated levels of CCL4, integrin αv and β3 expression. Similarly, an analysis of records from the Gene Expression Omnibus (GEO) dataset showed that CCL4 was upregulated in human osteosarcoma tissue. Importantly, the expression of both CCL4 and integrin αvβ3 correlated positively with osteosarcoma clinical stages and lung metastasis. Analysis of osteosarcoma cell lines identified that CCL4 promotes integrin αvβ3 expression and cell migration by activating the focal adhesion kinase (FAK), protein kinase B (AKT), and hypoxia inducible factor 1 subunit alpha (HIF-1α) signaling pathways, which can downregulate microRNA-3927-3p expression. Pharmacological inhibition of CCR5 by maraviroc (MVC) prevented increases in integrin αvβ3 expression and cell migration. This study is the first to implicate CCL4 as a potential target in the treatment of metastatic osteosarcoma.

MicroRNA-934 facilitates cell proliferation, migration, invasion and angiogenesis in colorectal cancer by targeting B-cell translocation gene 2

Colorectal cancer (CRC) is a global public health issue with increasing prevalence. MicroRNA-934 (miR-934) is a kind of non-coding RNA involved in the regulation of diverse cancers. Though previous researches have revealed part of association between miR-934 and CRC, the role of miR-934 in CRC pathogenesis has not been completely explored yet. In this study, we aim to investigate the effect of miR-934 on cell proliferation, migration, invasion and angiogenesis in CRC. Accordingly, miR-934 was found to be over-expressed in SW480 and HCT116 cells, two typical CRC cell lines. Meanwhile, miR-934 knockdown significantly inhibited cell proliferation and induced cell cycle arrest in SW480 and HCT116 cells. It was further validated that miR-934 knockdown displayed an inhibitory effect on cell migration and invasion in SW480 and HCT116 cells. Additionally, miR-934 deficiency markedly decreased VEGF expression in SW480 and HCT116 cells and suppressed capability of CRC cells to promote tube formation in vascular endothelial cells, which suggests the pro-angiogenesis role of miR-934 in vitro. Dual luciferase reporter assay further showed that miR-934 directly bound to B-cell translocation gene 2 (BTG2). BTG2 knockdown reversed the inhibitory effect of miR-934 silencing on cell proliferation, migration, invasion, and angiogenesis in SW480 and HCT116 cells. In summary, this study suggests that miR-934 facilitates CRC progression by targeting BTG2, and further highlights the role of miR-934 in pathogenesis of CRC.

The impact of particulate matter 2.5 on the risk of hepatocellular carcinoma: a meta-analysis

OBJECTIVE

The convoluted element of PM2.5 may cause various biological reactions. Nowadays, few studies have indicated the long-term health effects of PM2.5 on HCC. Therefore, this meta-analysis first aims to obtain more precise estimates of the effects of PM2.5 exposure on HCC to assess the strength of the evidence.

METHODS

A combination of computer and manual retrieval was used to search in Medline through PubMed, EMBASE and Web of Science. Review Manager 5.3 software was used to examine the heterogeneity among the studies.

RESULTS

Finally, 8 qualified articles meet the inclusion criteria. The results were I² = 0%, P > 0.1 indicating that there was no heterogeneity. The results showed that the concentration of PM2.5 increased by 10 μg/m³ was significantly correlated with liver cancer, and HR was 1.22 (95% CI 1.14-1.30, P < 0.05), indicating that maternal exposure to PM2.5 was positively correlated with liver cancer.

CONCLUSIONS

Our meta-analysis showed that the patients with HCC significance related to PM2.5 exposure. However, more studies investigating the combined effects of different air pollutants on HCC incidence are warranted to provide more comprehensive evidence for assessing the different levels impacts of PM2.5 exposure on HCC incidence.

FUT11 is a target gene of HIF1α that promotes the progression of hepatocellular carcinoma

Hypoxia promotes the progression of hepatocellular carcinoma. However, the hypoxia regulatory network in hepatocellular carcinoma is known to be limited. Thus, this study aimed to identify the crucial hypoxia-associated genes and to explore their effects and molecular mechanisms in hepatocellular carcinoma cells. FUT11 was first identified as a crucial hypoxia-associated gene through bioinformatics analysis. High FUT11 mRNA levels were positively correlated with poor clinical parameters. FUT11 knockdown under normoxia and hypoxia both decreased hepatocellular carcinoma cell proliferation, colony formation, migration, and invasion. HIF1α binds to the promoter of FUT11 and increases its transcription and co-expression with FUT11 in hepatocellular carcinoma tissues. Overexpression of FUT11 in HIF1α knockdown cells reversed the inhibitory effects of HIF1α suppression on hepatocellular carcinoma cell proliferation and mobility under hypoxia. Therefore, our findings indicate that FUT11 is a key target gene of HIF1α, which can promote the proliferation and mobility of hepatocellular carcinoma cells. FUT11 may be a novel and effective target for blocking the hypoxia response of hepatocellular carcinoma cells.

Repression of the miR-627-5p by histone deacetylase 3 contributes to hypoxia-induced hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is one of the most common solid tumors globally. Our previous studies revealed that miR-627-5p suppresses HCC progression via targeting BCL3/CCND1 pathway. However, the molecular mechanism by which miR-627-5p was downregulated in HCC remains to be further elucidated. As a hallmark of solid tumors, hypoxia results in the rapid growth, strongly potential invasion and high frequent metastasis of cancer cells. Hypoxia-inducible factors (HIFs), mainly including HIF-1 and HIF-2, are the classical transcription factors which mediate hypoxia-related gene transcription. Here, we demonstrated that miR-627-5p was repressed by hypoxia in a HIF-1-dependent manner in HCC cells. But HIF-1 regulated miR-627-5p expression not directly through the hypoxia-response element (HRE) sites of MIR627 gene. In contrast, histone deacetylase 3 (HDAC3) was identified as a HIF-1 target gene, and the occupancy of HIF-1 to HRE site was essential for hypoxia-mediated HDAC3 induction. And upregulated HDAC3 was closely related to the malignant clinical and pathological characteristics and worse prognosis of HCC. Furthermore, HDAC3-mediated histone deacetylation in promoter region of MIR627 was critical for hypoxia-mediated miR-627-5p repression. And miR-627-5p mediated the effects of hypoxic condition on HCC progression. Thus, this study has revealed that miR-627-5p was repressed by hypoxia under the mediation of HDAC3 in HCC, and there existed a HIF-1α/HDAC3/miR-627-5p/BCL3/CCND1 signal pathway in HCC.

HIF-1α-activated TM4SF1-AS1 promotes the proliferation, migration, and invasion of hepatocellular carcinoma cells by enhancing TM4SF1 expression

Long non-coding RNAs (lncRNAs) are essential drivers or suppressors in human hepatocellular carcinoma (HCC) by participating in controlling transcription, translation, mRNA stability, and protein degradation protein-protein interaction. TM4SF1-AS1 is recently identified as a tumor-promoting factor in lung cancer. Nevertheless, its function in HCC and related molecular mechanisms remain unknown. Here, our data indicated that either hypoxia or hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor (DMOG) induced the upregulation of TM4SF1-AS1 in HCC cells. HIF-1α knockdown rather than HIF-2α silencing remarkably abrogated hypoxia-upregulated TM4SF1-AS1 expression. Furthermore, we confirmed the elevated expression of TM4SF1-AS1 in HCC tissue samples and cell lines. The silencing of TM4SF1-AS1 prominently inhibited the proliferative, migratory, and invasive abilities of HCC cells. TM4SF1-AS1 depletion significantly blocked hypoxia-enhanced Hep3B cell proliferation and mobility. Interfering TM4SF1-AS1 remarkably reduced TM4SF1 mRNA and protein levels in HCC cells. But TM4SF1-AS1 knockdown did not impact the stability of TM4SF1 mRNA. Hypoxia enhanced the expression of TM4SF1 mRNA, which was subsequently decreased by TM4SF1-AS1 knockdown in HCC cells. We confirmed the positive correlation between TM4SF1 mRNA and TM4SF1-AS1 expression in HCC specimens. Finally, TM4SF1 prominently reversed the inhibitory role of TM4SF1-AS1 depletion in Hep3B cells. In summary, hypoxia-responsive TM4SF1-AS1 was overexpressed in human HCC and contributed to the malignant behaviors of tumor cells by enhancing TM4SF1-AS1 expression.

Ginsenoside CK Inhibits Hypoxia-Induced Epithelial-Mesenchymal Transformation through the HIF-1α/NF-κB Feedback Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a kind of malignant tumor with high morbidity and mortality rates worldwide. Epithelial-mesenchymal transformation (EMT) is crucial for HCC progression and prognosis. Characteristics of the tumor microenvironment, such as hypoxia, and excessive activation of the NF-κB signaling pathway have been identified as the key inducers of EMT in HCC. In our study, we verified the crosstalk between HIF-1α signaling and NF-κB pathway and their effects on EMT in HCC cells. The results show that CoCl₂-induced hypoxia could promote IκB phosphorylation to activate NF-κB signaling and vice versa. Moreover, we found that ginsenoside CK, a metabolite of protopanaxadiol saponins, could inhibit the proliferation and colony formation of different HCC cell lines. Furthermore, ginsenoside CK could impair the metastatic potential of HCC cell lines under hypoxic conditions. Mechanistically, ginsenoside CK suppressed HIF-1α/NF-κB signaling and expression level of EMT-related proteins and cytokines in hypoxia-induced or TNFα-stimulated HCC cell lines. An in vivo study revealed that the oral delivery of ginsenoside CK could inhibit the growth of xenograft tumors and block HIF-1α and NF-κB signaling as well as EMT marker expression. Our study suggests that ginsenoside CK is a potential therapy for HCC patients that functions by targeting the HIF-1α/NF-κB crosstalk.

Employing hypoxia characterization to predict tumour immune microenvironment, treatment sensitivity and prognosis in hepatocellular carcinoma

The hypoxic microenvironment was recognized as a major driving force of the malignant phenotype in hepatocellular carcinoma (HCC), which contributes to tumour immune microenvironment (TIM) remodeling and tumor progression. Dysregulated hypoxia-related genes (HRGs) result in treatment resistance and poor prognosis by reshaping tumor cellular activities and metabolism. Approaches to identify the relationship between hypoxia and tumor progression provided new sight for improving tumor treatment and prognosis. But, few practical tools, forecasting relationship between hypoxia, TIM, treatment sensitivity and prognosis in HCC were reported. Here, we pooled mRNA transcriptome and clinical pathology data from the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), and later developed a hypoxia risk model including four HRGs (DCN, DDIT4, PRKCA and NDRG1). The high-risk group displayed poor clinical characteristics, a malignant phenotype with carcinogenesis/proliferation pathways activation (MTORC1 and E2F) and immunosuppressive TIM (decreased immune cell infiltrations and upregulated immunosuppressive cytokines). Meanwhile, activated B cells, effector memory CD8 T cells and EZH2 deregulation were associated with patient’s survival, which might be the core changes of HCC hypoxia. Finally, we validated the ability of the hypoxia risk model to predict treatment sensitivity and found high hypoxia risk patients had poor responses to HCC treatment, including surgical resection, Sorafenib, Transarterial Chemoembolization (TACE) and immunotherapy. In conclusion, based on 4 HRGs, we developed and validated a hypoxia risk model to reflect pathological features, evaluate TIM landscape, predict treatment sensitivity and compounds specific to hypoxia signatures in HCC patients.

Tumor suppressor DCAF15 inhibits epithelial-mesenchymal transition by targeting ZEB1 for proteasomal degradation in hepatocellular carcinoma

Epithelial-mesenchymal transition (EMT) is an evolutionarily conserved developmental program that has been implicated in tumorigenesis and confers metastatic properties upon cancer cells. ZEB1 is a master transcription factor that activates the EMT process in various cancers. ZEB1 is reportedly degraded through the ubiquitin proteasome pathway, but the underlying molecular mechanism of this process remains largely unknown in hepatocellular carcinoma (HCC). Here, we identified ZEB1 as a substrate of the CRL4-DCAF15 (DDB1 and CUL4 associated factor 15) E3 ubiquitin ligase complex. DCAF15 acts as an adaptor that specifically recognizes the N-terminal zinc finger domain of ZEB1, then triggers its degradation via the ubiquitin-proteasome pathway. DCAF15 knockdown led to upregulation of ZEB1 and activation of EMT, whereas overexpression of DCAF15 suppressed ZEB1 and inhibited EMT. DCAF15 knockdown also promoted HCC cell proliferation and invasion in a ZEB1-dependent manner. In HCC patients, low DCAF15 expression was predictive of an unfavorable prognosis. These findings reveal the distinct molecular mechanism by which DCAF15 suppresses HCC malignancy and provides insight into the relationship between the CUL4-DCAF15 E3 ubiquitin ligase complex and ZEB1 in HCC.

Hypoxia-induced cofilin 1 promotes hepatocellular carcinoma progression by regulating the PLD1/AKT pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the fourth fatal malignant tumour type worldwide. However, the exact molecular mechanism involved in HCC progression remains unclear.

METHODS

Three pairs of HCC and matched portal vein tumour thrombus (PVTT) tissue samples were analysed by isobaric tags for relative and absolute quantification (iTRAQ) assay to investigate the differentially expressed proteins. Real-time quantitative PCR, immunostaining, and immunoblotting were performed to detect cofilin 1 (CFL1) in HCC and non-tumour tissues. CCK8 and EdU, and Transwell assays, respectively, determined cell proliferation, migration, and invasion of HCC cells. Further, subcutaneous and tail vein injection were performed in nude mice for investigating HCC growth and lung metastasis in vivo. Regulatory effect of hypoxia-inducible factor-1α (HIF-1α) on CFL1 was confirmed by chromatin immunoprecipitation (ChIP) assay. Finally, interaction between CFL1 and phospholipase D1 (PLD1) was studied using immunoprecipitation (IP) assay.

RESULTS

The iTRAQ analysis identified expression of CFL1 to be significantly upregulated in PVTT than in HCC tissues. Increased expression of CFL1 was closely associated with unfavourable clinical features, and was an independent risk predictor of overall survival in HCC patients. The knockdown of CFL1 inhibited cell growth viability, invasiveness, and epithelial-mesenchymal transformation (EMT) in HCC cells. Furthermore, CFL1 silencing significantly suppressed the growth and lung metastasis of HCC cells in nude mice. Next, HIF-1α directly regulated CFL1 transcription by binding to the hypoxia-responsive element (HRE) in the promoter. Moreover, we disclosed the interaction between CFL1 and PLD1 in HCC cells using IP assay. Mechanistically, CFL1 maintained PLD1 expression by repressing ubiquitin-mediated protein degradation, thereby activating AKT signalling in HCC cells. Notably, the CFL1/PLD1 axis was found mediating the hypoxia-induced activation of the AKT pathway and EMT.

CONCLUSION

The analysis suggests that hypoxia-induced CFL1 increases the proliferation, migration, invasion, and EMT in HCC by activating the PLD1/AKT pathway.

Role of vasodilator-stimulated phosphoprotein in RANKL-differentiated murine macrophage RAW264.7 cells: Modulation of NF-κB, c-Fos and NFATc1 transcription factors

Vasodilator-stimulated phosphoprotein (VASP) is essential for osteoclast differentiation, and reduced VASP expression results in depressed osteoclast differentiation. Previously, we demonstrated the importance of VASP and Ras-related C3 botulinum toxin substrate 1 interactions in osteosarcoma cell migration and metastasis using Mg-63 and Saos2 cells. However, the molecular details of the functional role of VASP in cell motility and migration remain to be elucidated. The present study demonstrated that VASP affects the expression of αV-integrin, tartrate-resistant acid phosphatase (TRAP) and lamellipodia protrusion in RAW 264.7 murine macrophage cells. The RAW 264.7 mouse monocyte macrophage cell line was used as an osteoclast precursor. RAW 264.7 cells were treated with 50 ng/ml of receptor activator of nuclear factor κ-Β ligand (RANKL) in order to induce cell differentiation (osteoclastogenesis). Small interfering RNA (siRNA) was used to silence VASP, and RT-PCR and western blotting were used to determine the expression for genes and proteins, respectively. TRAP staining as a histochemical marker for osteoclast and fluorescent microscopy for lamellipodia protrusion was performed. RANKL treatment significantly increased the gene and protein expression of VASP, αV-integrin and TRAP in RAW 264.7 cells. Silencing of VASP significantly reduced the RANKL-induced expression of αV-integrin, TRAP and lamellipodia protrusion. In addition, knockdown of VASP attenuated RANKL-stimulated activation of NF-κB, c-Fos and nuclear factor of activated T cells cytoplasmic 1 transcription factors, and the phosphorylation of the p65 and IκBα. These results suggest the critical role of VASP in regulating osteoclast differentiation, which should be further explored in osteosarcoma research.

Hypoxia-Induced Non-Coding RNAs Controlling Cell Viability in Cancer

Hypoxia, a characteristic of the tumour microenvironment, plays a crucial role in cancer progression and therapeutic response. The hypoxia-inducible factors (HIF-1α, HIF-2α, and HIF-3α), are the master regulators in response to low oxygen partial pressure, modulating hypoxic gene expression and signalling transduction pathways. HIFs’ activation is sufficient to change the cell phenotype at multiple levels, by modulating several biological activities from metabolism to the cell cycle and providing the cell with new characteristics that make it more aggressive. In the past few decades, growing numbers of studies have revealed the importance of non-coding RNAs (ncRNAs) as molecular mediators in the establishment of hypoxic response, playing important roles in regulating hypoxic gene expression at the transcriptional, post-transcriptional, translational, and posttranslational levels. Here, we review recent findings on the different roles of hypoxia-induced ncRNAs in cancer focusing on the data that revealed their involvement in tumour growth.

Identification of a Novel Metastasis-Related miRNAs-Based Signature for Predicting the Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common internal malignancies worldwide and is associated with a poor prognosis. Abnormal expression of miRNAs is believed to play a role in the recurrent metastasis of HCC. However, limited studies on the role of miRNAs in HCC metastasis have been carried out. Therefore, this study is aimed at exploring the potential value of metastasis-related miRNAs (MRMs) in HCC. We retrieved MRMs were from the Human Cancer Metastasis Database. Differential miRNAs were identified for tumor samples of HCC patients and normal samples based on the TCGA database. Further, univariate and multivariate Cox regression analyses were used to screen MRMs known to be independent prognostic factors in HCC. These MRMs were then used to build a prognostic signature. All patients were classified into high-risk and low-risk groups based on the median of the signature scores. Moreover, GO and KEGG pathway enrichment analyses were performed to predict the function of these MRMs. Finally, a nomogram was constructed to predict the OS of patients at 1, 2, and 3 years. In our study, a total of seven prognostic MRMs (miR-140-3p, miR-9-5p, miR-942-5p, miR-324-3p, miR-29c-5p, miR-551a, and miR-149-5p) were identified and used for constructing the prognostic signature based on the training cohort. Patients in the low-risk HCC group showed better overall survival (OS) than those in the high-risk group. The results were validated using the validation cohort. In summary, the findings of this study provide evidence that MRMs-based prognostic signature is an independent biomarker in the prognosis of HCC patients.

Cinnamaldehyde mitigates placental vascular dysfunction of gestational diabetes and protects from the associated fetal hypoxia by modulating placental angiogenesis, metabolic activity and oxidative stress

Gestational diabetes mellitus (GDM) is a major pregnancy-related disorder with an increasing prevalence worldwide. GDM is associated with altered placental vascular functions and has severe consequences for fetal growth. There is no commonly accepted medication for GDM due to safety considerations. Actions of the currently limited therapeutic options focus exclusively on lowering the blood glucose level without paying attention to the altered placental vascular reactivity and remodelling. We used the fat-sucrose diet/streptozotocin (FSD/STZ) rat model of GDM to explore the efficacy of cinnamaldehyde (Ci; 20 mg/kg/day), a promising antidiabetic agent for GDM, and glyburide/metformin-HCl (Gly/Met; 0.6 + 100 mg/kg/day), as a reference drug for treatment of GDM, on the placenta structure and function at term pregnancy after their oral intake one week before mating onward. Through genome-wide transcriptome, biochemical, metabolome, metal analysis and histopathology we obtained an integrated understanding of their effects. GDM resulted in maternal and fetal hyperglycemia, fetal hyperinsulinemia and placental dysfunction with subsequent fetal anemia, hepatic iron deficiency and high serum erythropoietin level, reflecting fetal hypoxia. Differentially-regulated genes were overrepresented for pathways of angiogenesis, metabolic transporters and oxidative stress. Despite Ci and Gly/Met effectively alleviated the maternal and fetal glycemia, only Ci offered substantial protection from GDM-associated placental vasculopathy and prevented the fetal hypoxia. This was explained by Ci's impact on the molecular regulation of placental angiogenesis, metabolic activity and redox signaling. In conclusion, Ci provides a dual impact for the treatment of GDM at both maternal and fetal levels through its antidiabetic effect and the direct placental vasoprotective action. Lack of Gly/Met effectiveness to restore it's impaired functionality demonstrates the vital role of the placenta in developing efficient medications for GDM.

Identification of the atypical cadherin FAT1 as a novel glypican-3 interacting protein in liver cancer cells

Glypican-3 (GPC3) is a cell surface heparan sulfate proteoglycan that is being evaluated as an emerging therapeutic target in hepatocellular carcinoma (HCC). GPC3 has been shown to interact with several extracellular signaling molecules, including Wnt, HGF, and Hedgehog. Here, we reported a cell surface transmembrane protein (FAT1) as a new GPC3 interacting protein. The GPC3 binding region on FAT1 was initially mapped to the C-terminal region (Q14517, residues 3662-4181), which covered a putative receptor tyrosine phosphatase (RTP)-like domain, a Laminin G-like domain, and five EGF-like domains. Fine mapping by ELISA and flow cytometry showed that the last four EGF-like domains (residues 4013-4181) contained a specific GPC3 binding site, whereas the RTP domain (residues 3662-3788) and the downstream Laminin G-2nd EGF-like region (residues 3829-4050) had non-specific GPC3 binding. In support of their interaction, GPC3 and FAT1 behaved concomitantly or at a similar pattern, e.g. having elevated expression in HCC cells, being up-regulated under hypoxia conditions, and being able to regulate the expression of EMT-related genes Snail, Vimentin, and E-Cadherin and promoting HCC cell migration. Taken together, our study provides the initial evidence for the novel mechanism of GPC3 and FAT1 in promoting HCC cell migration.

Pro-protein convertase subtilisin/kexin type 9 promotes intestinal tumor development by activating Janus kinase 2/signal transducer and activator of transcription 3/SOCS3 signaling in ApcMin/+ mice

INTRODUCTION

Pro-protein convertase subtilisin/kexin type 9 (PCSK9) regulates lipoprotein homeostasis in humans. Evolocumab is a selective PCSK9 inhibitor that can reduce low-density lipoprotein cholesterol (LDLC) level and decrease hypercholesterolemia. The current study aimed to explore whether PCSK9 increases the risk of colorectal cancer.

METHODS

First, we utilized the classic intestinal tumor ApcMin/+ mouse model and PCSK9 knock-in (KI) mice to establish ApcMin/+PCSK9(KI) mice. Then, we investigated the effect of PCSK9 overexpression in ApcMin/+PCSK9(KI) mice and PCSK9 inhibition using evolocumab on the progression of intestinal tumors in vivo by hematoxylin and eosin (HE) staining, Western blot, and immunohistochemistry (IHC) assay.

RESULTS

ApcMin/+PCSK9(KI) mice had higher numbers and larger sizes of adenomas, with 83.3% of these mice developing adenocarcinoma (vs. 16.7% of ApcMin/+ mice). However, treatment with evolocumab reduced the number and size of adenomas and prevented the development of adenocarcinomas in ApcMin/+ mice. PCSK9 overexpression reduced tumor cell apoptosis, the Bax/bcl-2 ratio, and the levels of cytokine signaling 3 protein (SOCS3) suppressors, but activated Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling in intestinal tumors. In contrast, evolocumab treatment had the opposite effect on ApcMin/+mice.

CONCLUSION

PCSK9 might act as an oncogene or have an oncogenic role in the development and progression of colorectal cancer in vivo via activation of JAK2/STAT3/SOCS3 signaling.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

AQP9 suppresses hepatocellular carcinoma cell invasion through inhibition of hypoxia-inducible factor 1α expression under hypoxia

BACKGROUND AND AIM

Intratumor hypoxia is a hallmark of hepatocellular carcinoma (HCC) and is associated with an aggressive tumor phenotype. Although it has been shown that AQP9 plays an important role in HCC, the relevance between hypoxia and AQP9 is still unknown.

METHODS

We established in vitro normoxic or hypoxic models to investigate the role of AQP9 in the regulation of hypoxia-inducible factor 1α (HIF-1α) and hypoxia-enhanced invasion of hepatoma cells. Molecular expression was detected using western blot or quantitative polymerase chain reaction. Cell invasion ability was determined using Transwell invasion assay. In vivo xenograft experiment was used to detect the role of AQP9 on tumor growth.

RESULTS

Our present study revealed a decrease in the expression levels of AQP9 in hypoxic microenvironments. Overexpression of AQP9 led to a decreased expression of HIF-1α; conversely, suppression of AQP9 in HCC cells had an opposite effect. Furthermore, up-regulated AQP9 blocked the hypoxic-enhanced invasion of HCC cells. The overexpression of AQP9 inhibited the growth of tumors and HIF-1α expression in vivo.

CONCLUSIONS

These data suggest that AQP9 acts as a tumor suppressor in HCC invasion via the regulation of HIF-1α expression in the tumor hypoxic microenvironment.

Long noncoding RNA PICSAR/miR-588/EIF6 axis regulates tumorigenesis of hepatocellular carcinoma by activating PI3K/AKT/mTOR signaling pathway

Accumulating evidence has identified long noncoding RNAs (lncRNAs) as regulators in tumor progression and development. Here, we elucidated the function and possible molecular mechanisms of the effect of lncRNA-PICSAR (p38 inhibited cutaneous squamous cell carcinoma associated lincRNA) on the biological behaviors of HCC. In the present study, we found that PICSAR was upregulated in HCC tissues and cells and correlated with progression and poor prognosis in HCC patients. Gain- and loss-of-function experiments indicated that PICSAR enhanced cell proliferation, colony formation, and cell cycle progression and inhibited apoptosis of HCC cells. PICSAR could function as a competing endogenous RNA by sponging microRNA (miR)-588 in HCC cells. Mechanically, miR-588 inhibited HCC progression and alternation of miR-588 reversed the promotive effects of PICSAR on HCC cells. In addition, we confirmed that eukaryotic initiation factor 6 (EIF6) was a direct target of miR-588 in HCC and mediated the biological effects of miR-588 and PICSAR in HCC, resulting in PI3K/AKT/mTOR pathway activation. Our data identified PICSAR as a novel oncogenic lncRNA associated with malignant clinical outcomes in HCC patients. PICSAR played an oncogenic role by targeting miR-588 and subsequently promoted EIF6 expression and PI3K/AKT/mTOR activation in HCC. Our results revealed that PICSAR could be a potential prognostic biomarker and therapeutic target for HCC.

Hypoxia-Inducible Ubiquitin Specific Peptidase 13 Contributes to Tumor Growth and Metastasis via Enhancing the Toll-Like Receptor 4/Myeloid Differentiation Primary Response Gene 88/Nuclear Factor-κB Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide. The activation of the toll-like receptor 4/myeloid differentiation primary response gene 88/nuclear factor-κB (TLR4/MyD88/NF-κB) pathway contributes to the development and progression of HCC. The ubiquitin-proteasome system regulates TLR4 expression. However, whether ubiquitin specific peptidase 13 (USP13) stabilizes TLR4 and facilitates HCC progression remains unclear. Here, quantitative real-time PCR (qRT-PCR) and immunohistochemistry analysis revealed that USP13 expression in HCC tissues was higher than in non-tumor liver tissues. Moreover, the elevated expression of USP13 was detected in HCC cells (SK-HEP-1, HepG2, Huh7, and Hep3B) compared to LO2 cells. Interestingly, the positive staining of USP13 was closely correlated with tumor size ≥ 5 cm and advanced tumor stage and conferred to significantly lower survival of HCC patients. Next, USP13 knockdown prominently reduced the proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion of Hep3B and Huh7 cells, while USP13 overexpression enhanced these biological behaviors of HepG2 and LO2 cells. The silencing of USP13 significantly restrained the growth and lung metastasis of HCC cells in vivo. Mechanistically, the USP13 depletion markedly inhibited the TLR4/MyD88/NF-κB pathway in HCC cells. USP13 interacted with TLR4 and inhibited the ubiquitin-mediated degradation of TLR4. Significantly, TLR4 re-expression remarkably reversed the effects of USP13 knockdown on HCC cells. USP13 expression was markedly upregulated in HCC cells under hypoxia conditions. Notably, USP13 knockdown repressed hypoxia-induced activation of the TLR4/MyD88/NF-κB pathway in HCC cells. In conclusion, our study uncovered that hypoxia-induced USP13 facilitated HCC progression via enhancing TLR4 deubiquitination and subsequently activating the TLR4/MyD88/NF-κB pathway.

Hypoxia-inducible long noncoding RNA NPSR1-AS1 promotes the proliferation and glycolysis of hepatocellular carcinoma cells by regulating the MAPK/ERK pathway

Hepatocellular carcinoma (HCC), which accounts for approximately 90% of primary liver cancer, is commonly treated with surgical resection. However, most patients lose the opportunity to receive this therapeutic strategy due to delayed diagnosis and rapid tumor progression. Long noncoding RNAs (lncRNAs) have been demonstrated to play essential roles in the initiation and progression of HCC. However, the function of the novel lncRNA neuropeptide S receptor 1 antisense RNA 1 (NPSR1-AS1) in HCC and its potential mechanism, is unclear. Here, our microarray data revealed NPSR1-AS1 as a novel hypoxia-responsive lncRNA in HCC cells. Interestingly, hypoxia-inducible factor-1α (HIF-1α) knockdown abolished hypoxia-induced NPSR1-AS1 expression in HCC cells. NPSR1-AS1 expression was upregulated in HCC tissues and cell lines. Next, the ectopic expression of NPSR1-AS1 facilitated the proliferation and glycolysis of HCC cells. In contrast, NPSR1-AS1 silencing repressed HCC cell proliferation and glycolysis. Mechanistically, NPSR1-AS1 overexpression increased the levels of p-ERK1/2 and pyruvate kinase M2 (PKM2) in HCC cells. NPSR1-AS1 knockdown abrogated hypoxia-induced the activation of the MAPK/ERK pathway in HCC cells. Importantly, NPSR1-AS1 depletion partially reversed hypoxia-induced proliferation and glycolysis of HCC cells in vitro. In conclusion, hypoxia-inducible NPSR1-AS1 promotes the proliferation and glycolysis of HCC cells, possibly by regulating the MAPK/ERK pathway, suggesting an underlying therapeutic strategy for HCC.

A novel prognostic models for identifying the risk of hepatocellular carcinoma based on epithelial-mesenchymal transition-associated genes

Several epithelial-mesenchymal transition (EMT)-associated genes (EAGs) have been confirmed to correlate with the prognosis of hepatocellular carcinoma (HCC) patients. Herein, we explored the value of EAGs in the prognosis of HCC relying on data from The Cancer Genome Atlas (TCGA) database. A total of 200 EMT-associated genes were downloaded from the Gene set enrichment analysis (GSEA) website. Moreover, 96 differentially expressed EAGs were identified. Using Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, we forecasted the potential molecular mechanisms of EAGs. To identify prognostic EAGs, Cox regression was used in developing a prognostic risk model. Then, the Kaplan-Meier and receiver operating characteristic (ROC) curves were plotted to validate the prognostic significance of the model. A total of 5 prognostic correlated EAGs (P3H1, SPP1, MMP1, LGALS1, and ITGB5) were screened via Cox regression, which provided the basis for developing a novel prognostic risk model. Based on the risk model, patients were subdivided into high-risk and low-risk groups. The overall survival of the low-risk group was better compared to the high-risk group (P < 0.00001). The ROC curve of the risk model showed a higher AUC (Area under Curve) (AUC = 0.723) compared to other clinical features (AUC ≤ 0.511). A nomogram based on this model was constructed to predict the 1-year, 2-year, and 3-year overall survival rates (OS) of patients. Conclusively, we developed a novel HCC prognostic risk model based on the expression of EAGs, which help advance the prognostic management of HCC patients. Abbreviations: HCC: hepatocellular carcinoma; TCGA: The Cancer Genome Atlas; EMT: epithelial-mesenchymal transition; EAGs: EMT-associated genes; GSEA: gene set enrichment analysis; GO: Gene Ontology; KEGG: Kyoto Encyclopedia of Genes and Genomes; PPI: protein-protein interaction; TF: transcription factor; ROC: receiver operating characteristic; K-M: Kaplan-Meier; AUC: the area under the ROC curve; FDR: false discovery rate; TNM: Tumor size/lymph nodes/distance metastasis.

Hypoxia-induced epithelial to mesenchymal transition in cancer

A common feature of many solid tumors is low oxygen conditions due to inadequate blood supply. Hypoxia induces hypoxia inducible factor (HIF) stabilization and downstream signaling. This signaling has pleiotropic roles in cancers, including the promotion of cellular proliferation, changes in metabolism, and induction of angiogenesis. In addition, hypoxia is becoming recognized as an important driver of epithelial-to-mesenchymal (EMT) in cancer. During EMT, epithelial cells lose their typical polarized states and transition to a more mobile mesenchymal phenotype. Hypoxia induces this transition by modulating EMT signaling pathways, inducing EMT transcription factor activity, and regulating miRNA networks. As both hypoxia and EMT modulate the tumor microenvironment (TME) and are associated with immunosuppression, we also explore how these pathways may impact response to immuno-oncology therapeutics.

MicroRNA‑875‑5p inhibits tumor growth and metastasis of hepatocellular carcinoma by targeting eukaryotic translation initiation factor 3 subunit a

Accumulating evidence has demonstrated that aberrant microRNA (miRNA) expression is involved in hepatocellular carcinoma (HCC) progression. Previous findings suggested that miRNA (miR)‑875‑5p participates in the development of various types of cancer. However, the expression and function of miR‑875‑5p in HCC remains largely unclear. The analysis of clinical samples in the present study demonstrated that miR‑875‑5p expression was downregulated in HCC tissues compared to adjacent non‑tumor tissues, which was associated with a large tumor size, venous infiltration, advanced tumor‑node‑metastasis stage and unfavorable overall survival. In vitro experiments revealed that ectopic expression of miR‑875‑5p suppressed, whereas inhibition of miR‑875‑5p promoted HCC cell proliferation, migration, invasion and epithelial‑to‑mesenchymal transition (EMT) progression. Overexpression of miR‑875‑5p restrained HCC tumor growth and metastasis in vivo. Mechanistically, eukaryotic translation initiation factor 3 subunit a (eIF3a) was identified as the downstream target of miR‑875‑5p in HCC. Further experiments demonstrated that the expression of eIF3a was upregulated and negatively correlated with that of miR‑875‑5p in HCC tissues. In addition, miR‑875‑5p negatively regulated the luciferase activity of wild‑type, but not mutant 3'‑untranslated region (3'UTR) of eIF3a mRNA. miR‑875‑5p suppressed eIF3a expression at the mRNA and protein level in HCC cells. Additionally, eIF3a exerted an oncogenic role, and knockdown of eIF3a inhibited the proliferation, motility and EMT of HCC cells. In addition, eIF3a overexpression abolished the inhibitory effects of miR‑875‑5p on the proliferation, motility and EMT in HCC cells. In conclusion, miR‑875‑5p, which was downregulated in HCC, may inhibit tumor growth and metastasis by eIF3a downregulation via targeting its 3'UTR and may be a promising prognostic and therapeutic strategy in HCC.

ZNF521 which is downregulated by miR-802 suppresses malignant progression of Hepatocellular Carcinoma through regulating Runx2 expression

Zinc finger protein 521 (ZNF521) plays an important role in the tumor development and process. However, its regulatory role in hepatocellular carcinoma (HCC) remains unclear. In this study, we demonstrated for the first time that ZNF521 mRNA and protein was down-regulated in HCC tissues and cell lines. Down-regulated ZNF521 expression was significantly associated with malignant prognostic features, including advanced TNM stage and large tumor size. For 5-year survival, ZNF521 served as a potential prognostic marker of HCC patients. Moreover, ZNF521 inhibited cell proliferation, colony formation and cell viability through Runx2 transcriptional inhibition and AKT phosphorylation pathway. Moreover, we demonstrated that ZNF521 expression was regulated by miR-802. In HCC tissues. MiR-802 has an inverse correlation with ZNF521 expression. In conclusion, we demonstrate for the first time that ZNF521 is down-regulated in HCC tissues and inhibits HCC growth through Runx2 transcriptional inhibition and AKT inactivation, which was regulated by miR-802, suggesting the potential therapeutic value for HCC.

Glucometabolic Reprogramming in the Hepatocellular Carcinoma Microenvironment: Cause and Effect

Hepatocellular carcinoma (HCC) is a tumor that exhibits glucometabolic reprogramming, with a high incidence and poor prognosis. Usually, HCC is not discovered until an advanced stage. Sorafenib is almost the only drug that is effective at treating advanced HCC, and promising metabolism-related therapeutic targets of HCC are urgently needed. The “Warburg effect” illustrates that tumor cells tend to choose aerobic glycolysis over oxidative phosphorylation (OXPHOS), which is closely related to the features of the tumor microenvironment (TME). The HCC microenvironment consists of hypoxia, acidosis and immune suppression, and contributes to tumor glycolysis. In turn, the glycolysis of the tumor aggravates hypoxia, acidosis and immune suppression, and leads to tumor proliferation, angiogenesis, epithelial–mesenchymal transition (EMT), invasion and metastasis. In 2017, a mechanism underlying the effects of gluconeogenesis on inhibiting glycolysis and blockading HCC progression was proposed. Treating HCC by increasing gluconeogenesis has attracted increasing attention from scientists, but few articles have summarized it. In this review, we discuss the mechanisms associated with the TME, glycolysis and gluconeogenesis and the current treatments for HCC. We believe that a treatment combination of sorafenib with TME improvement and/or anti-Warburg therapies will set the trend of advanced HCC therapy in the future.

Hypoxia-Induced Placenta-Specific microRNA (miR-512-3p) Promotes Hepatocellular Carcinoma Progression by Targeting Large Tumor Suppressor Kinase 2

Background

Sustained proliferation and active metastasis are hallmarks of cancer, and they pose major challenges to the development of treatments and a cure for hepatocellular carcinoma (HCC). Thus, the mechanisms of proliferation, migration, and invasion of cancer cells need to be investigated. Many studies indicate that dysregulation of microRNA plays important roles in the progression of HCC, but the role of placenta-specific microRNA (miR-512-3p) in HCC has not been systematically investigated.

Purpose

In the current study, the expression, biological function, and mechanisms of miR-512-3p involvement in HCC were investigated.

Methods

Real-time quantitative polymerase chain reaction assays were conducted to determine miR-512-3p levels in HCC tissues and cell lines. The StarBase V3.0 online platform was used to compare miR-512-3p levels in HCC tissues with TCGA data and to identify potential miR-512-3p target genes. Associations between miR-512-3p and clinicopathological characteristics were analyzed statistically. MTT, ethynyl deoxyuridine, and transwell assays were performed to assess cell viability, proliferation, migration, and invasion. The luciferase reporter gene assay was used to verify target genes. Recuse assays were performed to confirm whether large tumor suppressor kinase 2 (LATS2) participated in the regulatory effects of miR-512-3p on HCC cell proliferation and motility, and whether miR-512-3p mediated the tumor-promoting effects of hypoxia.

Results

miR-512-3p was upregulated in HCC and it was associated with worse survival and unfavorable clinicopathological characteristics. Functional assays indicated that miR-512-3p contributed to HCC cell proliferation, migration, and invasion. Mechanistically, LATS2—a downstream target of miR-512-3p—mediated the tumor-promoting effects of miR-512-3p in HCC. Hypoxia could elevate miR-512-3p levels in HCC cells, and miR-512-3p partially mediated the tumor-promoting effects of hypoxia.

Conclusion

Hypoxia-induced miR-512-3p contributes to HCC cell proliferation, migration, and invasion by targeting LATS2 and inhibiting the Hippo/yes-associated protein 1 pathways.

ZKSCAN3 drives tumor metastasis via integrin β4/FAK/AKT mediated epithelial-mesenchymal transition in hepatocellular carcinoma

BACKGROUND

ZKSCAN3, a zinc-finger transcription factor containing KRAB and SCAN domains, has been reported to be regulated in several human cancers. However, its expression and function in hepatocellular carcinoma (HCC) remains unknown.

METHODS

Expression of ZKSCAN3 in HCC was analyzed by western blotting, immunohistochemistry, and real time PCR. Its correlation with the clinicopathological characteristics and prognosis of HCC patients was analyzed. The effects of ZKSCAN3 on the migration and invasion were determined by Transwell assays. The potential downstream targets of ZKSCAN3 and related molecular mechanisms were clarified by Western blot and dual luciferase reporter assay.

RESULTS

In this study, we demonstrated for the first time that ZKSCAN3 mRNA and protein was up-regulated in HCC tissues and cell lines. High ZKSCAN3 expression was significantly associated with poor prognostic features, including advanced TNM stage and vascular invasion. For 5-year survival, ZKSCAN3 served as a potential prognostic marker of HCC patients. Functionally, ZKSCAN3 promoted migration, invasion and EMT progress via directly binding to integrin β4 (ITGB4) promoter and enhanced its expression. Further investigation proved that ITGB4 triggers the focal adhesion kinase (FAK) to activate the AKT signaling pathway. Inactivation of FAK and AKT by their specific inhibitors respectively reversed the effects of ZKSCAN3 on HCC cells. In addition, we demonstrated that ZKSCAN3 expression was regulated by miR-124. In HCC tissues. MiR-124 has an inverse correlation with ZKSCAN3 expression.

CONCLUSION

We demonstrate for the first time that ZKSCAN3 is overexpressed in HCC tissues and promotes migration, invasion and EMT process through ITGB4-dependent FAK/AKT activation, which was regulated by miR-124, suggesting the potential therapeutic value for HCC.

CXCR4 mediates matrix stiffness-induced downregulation of UBTD1 driving hepatocellular carcinoma progression via YAP signaling pathway

Rational: Increasing evidence indicates that the physical environment is a critical mediator of tumor behavior. Hepatocellular carcinoma (HCC) develops in an altered biomechanical environment, and increased matrix stiffness is a strong predictor of HCC development. C-X-C chemokine receptor type 4 (CXCR4) is known to trigger HCC progression. However, CXCR4 as a mediator of mechanical cues in HCC is not well characterized.

Methods: qRT-PCR, Western blot and IHC were used to detect the CXCR4 expression in different matrix stiffness gels. MTT was used to measure the cell proliferation of HCC cells. Immunoblotting was used for detection of epithelial-to-mesenchymal transition (EMT) and stemness on the matrix stiffness. Immunofluorescence (IF) was used to detect the nuclear location in HCC cells. IP was used to show the interaction between YAP, UbcH5c and β-TrCP.

Results: We identified CXCR4 as a critical intracellular signal transducer that relays matrix stiffness signals to control mechano-sensitive cellular activities through ubiquitin domain-containing protein 1 (UBTD1)-mediated YAP signaling pathway. We found that CXCR4 expression was remarkably up-regulated in HCC cells with increasing matrix stiffness and mediated proliferation, epithelial to mesenchymal transition, and stemness. Mechanistically, matrix stiffness acts through CXCR4 to decrease the levels of UBTD1, which is involved in the proteasome-dependent degradation of YAP, a major cell mechano-transducer. UBTD1 interacted with components of the YAP degradation complex and promoted the interaction between YAP and its E3 ubiquitin ligase β-TrCP. UBTD1 knockdown decreased YAP ubiquitylation and resulted in the activation of YAP-targeted genes and YAP downstream signaling. Downregulation of UBTD1 in HCC tissues correlated with malignant prognostic features and overall survival. Finally, luteolin, a natural product, suppressed matrix stiffness-induced biological effects and CXCR4-mediated YAP signaling pathway in HCC cells.

Conclusion: Our findings reveal CXCR4 as a molecular switch in mechano-transduction, thereby defining a mechano-signaling pathway from matrix stiffness to the nucleus.

The Metastasis Potential Promoting Capacity of Cancer-Associated Fibroblasts Was Attenuated by Cisplatin via Modulating KRT8

Background

Cancer-associated fibroblasts (CAFs) are an essential component of tumor microenvironment. They are attracting increasing attentions due to their crucial role in tumor growth, drug-resistance and metastasis. Cisplatin is a first-line chemotherapy drug applying in various types of cancer. There are intensive studies on cisplatin's effect on tumor cells, however, its effect on CAFs remains poorly understood. In the present study, we investigated the effect of cisplatin on CAFs.

Methods

Cell migration was detected by wound healing assay. Cell invasion was performed by the transwell assay. mRNA expression was detected by quantitative PCR, and protein expression was detected by Western blotting. Tumor growth was measured using BALB/c nude mice tumor models.

Results

Cisplatin attenuated the promoting capacity of CAFs on lung cancer cell migration and invasion, via suppressing CAFs' effect on metastasis-related genes including Twist1, vascular endothelial growth factor receptor (VEGFR), MMP2, and AKT signaling pathway. Keratin 8 (KRT8) was identified as a target of cisplatin. KRT8 upregulation in CAFs is responsible for the inhibitory effect of cisplatin on lung cancer cells metastasis potential through AKT pathway suppression. The stimulation of AKT by AKT activator SC79 reversed KRT8's effect on cell migration. Importantly, in vivo study also showed that CAFs enhanced tumor growth significantly, and cisplatin effectively abrogated the promoting effect of CAFs on tumor growth.

Conclusion

Our results revealed a novel mechanism that cisplatin attenuated the metastasis promoting effect of CAFs via KRT8/AKT signaling pathway. This finding highlights KRT8 in CAFs as a potential therapeutic candidate for metastasis treatment.

G9a-mediated repression of CDH10 in hypoxia enhances breast tumour cell motility and associates with poor survival outcome

Rationale: Epigenetic mechanisms are fundamental processes that can modulate gene expression, allowing cellular adaptation to environmental conditions. Hypoxia is an important factor known to initiate the metastatic cascade in cancer, activating cell motility and invasion by silencing cell adhesion genes. G9a is a histone methyltransferase previously shown to accumulate in hypoxic conditions. While its oncogenic activity has been previously reported, not much is known about the role G9a plays in the hypoxia-mediated metastatic cascade.

Methods: The role of G9a in cell motility in hypoxic condition was determined by inhibiting G9a either by short-hairpin mediated knock down or pharmacologically using a small molecule inhibitor. Through gene expression profiling, we identified CDH10 to be an important G9a target that regulates breast cancer cell motility. Lung metastasis assay in mice was used to determine the physiological significance of G9a.

Results: We demonstrate that, while hypoxia enhances breast cancer migratory capacity, blocking G9a severely reduces cellular motility under both normoxic and hypoxic conditions and prevents the hypoxia-mediated induction of cellular movement. Moreover, inhibition of G9a histone methyltransferase activity in mice using a specific small molecule inhibitor significantly reduced growth and colonisation of breast cancer cells in the lung. We identify the type-II cadherin CDH10 as being a novel hypoxia-dependent gene, directly repressed by G9a through histone methylation. CDH10 overexpression significantly reduces cellular movements in breast cancer cell lines and prevents the hypoxia-mediated increase in cell motility. In addition, we show that CDH10 expression is prognostic in breast cancer and that it is inversely correlated to EHMT2 (G9a) transcript levels in many tumor-types, including breast cancer.

Conclusion: We propose that G9a promotes cellular motility during hypoxic stress through the silencing of the cell adhesion molecule CDH10 and we describe CDH10 as a novel prognostic biomarker for breast cancer.

Interleukin 1β-mediated HOXC10 Overexpression Promotes Hepatocellular Carcinoma Metastasis by Upregulating PDPK1 and VASP

Rationale: Metastasis and recurrence are the primary reasons for the high mortality rate of human hepatocellular carcinoma (HCC) patients. However, the exact mechanism underlying HCC metastasis remains unclear. The Homeobox (HOX) family proteins, which are a highly conserved transcription factor superfamily, play important roles in cancer metastasis. Here, we report a novel role of HOXC10, one of the most upregulated HOX genes in human HCC tissues, in promoting HCC metastasis.

Methods: The expression of HOXC10 and its functional targets was detected by immunohistochemistry in two independent human HCC cohorts. Luciferase reporter and chromatin immunoprecipitation assays were used to measure the transcriptional regulation of target genes by HOXC10. The effect of HOXC10-mediated invasion and metastasis were analyzed by Transwell assays and by an orthotopic metastasis model.

Results: Elevated expression of HOXC10 was positively correlated with the loss of tumor encapsulation and with higher tumor-nodule-metastasis (TNM) stage and poor prognosis in human HCC. Overexpression of HOXC10 promoted HCC metastasis by upregulating metastasis-related genes, including 3-phosphoinositide-dependent protein kinase 1 (PDPK1) and vasodilator-stimulated phosphoprotein (VASP). Knockdown of PDPK1 and VASP inhibited HOXC10-enhanced HCC metastasis, whereas upregulation of PDPK1 and VASP rescued the decreased metastasis induced by HOXC10 knockdown. Interleukin-1β (IL-1β), which is the ligand of IL-1R1, upregulated HOXC10 expression through the c-Jun NH2-terminal kinase (JNK)/c-Jun pathway. HOXC10 knockdown significantly reduced IL-1β-mediated HCC metastasis. Furthermore, Anakinra, a specific antagonist of IL-1R1, inhibited IL-1β-induced HOXC10 upregulation and HCC metastasis. In human HCC tissues, HOXC10 expression was positively correlated with PDPK1, VASP and IL-1R1 expression, and patients with positive coexpression of HOXC10/PDPK1, HOXC10/VASP or IL-1R1/HOXC10 exhibited the poorest prognosis.

Conclusions: Upregulated HOXC10 induced by IL-1β promotes HCC metastasis by transactivating PDPK1 and VASP expression. Thus, our study implicates HOXC10 as a prognostic biomarker, and targeting this pathway may be a promising therapeutic option for the clinical prevention of HCC metastasis.