Hepatocyte nuclear factor 4 alpha promotes the invasion, metastasis and angiogenesis of neuroblastoma cells via targeting matrix metalloproteinase 14

HNF6 and HNF4α expression in adenocarcinomas of the liver, pancreaticobiliary tract, and gastrointestinal tract: an immunohistochemical study of 480 adenocarcinomas of the digestive system

Hepatocyte nuclear factors (HNF) 6 and 4α are master transcriptional regulators of development and maintenance of the liver and pancreaticobiliary tract in mice and humans. However, little is known about the prevalence of HNF6 and HNF4α expression in carcinomas of the hepatobiliary tract and pancreas. We aimed to reveal the diagnostic utility of HNF6 and HNF4α immunolabelling in adenocarcinomas of these organs. We investigated HNF6 and HNF4α expression by immunohistochemistry using a total of 480 adenocarcinomas of the digestive system, including 282 of the hepatobiliary tract and pancreas and 198 of the gastrointestinal tract. HNF6 expression was primarily restricted to intrahepatic cholangiocarcinomas (CCs) (63%, n=80) and gallbladder adenocarcinomas (43%, n=88), among others. Notably, small duct intrahepatic CCs almost invariably expressed HNF6 (90%, n=42), showing stark contrast to a low prevalence in large duct intrahepatic CCs (10%, n=21; p<0.0001). HNF6 expression was infrequent in extrahepatic CCs (9%, n=55) and pancreatic ductal adenocarcinomas (7%, n=58), and it was rare in adenocarcinomas of the gastrointestinal tract [oesophagus/oesophagogastric junction (EGJ) (2%, n=45), stomach (2%, n=86), duodenum (0%, n=25), and colorectum (0%, n=42)]. In contrast, HNF4α was widely expressed among adenocarcinomas of the digestive system, including intrahepatic CCs (88%), extrahepatic CCs (94%), adenocarcinomas of the gallbladder (98%), pancreas (98%), oesophagus/EGJ (96%), stomach (98%), duodenum (80%), and colorectum (100%). HNF6 was frequently expressed in and almost restricted to intrahepatic CCs of small duct type and gallbladder adenocarcinomas, while HNF4α was expressed throughout adenocarcinomas of the digestive system. HNF6 immunolabelling may be useful in distinguishing small duct intrahepatic CCs from other types of CC as well as metastatic gastrointestinal adenocarcinomas.

Hepatocyte nuclear factor 4 a (HNF4α): A perspective in cancer

HNF4α, a transcription factor, plays a vital role in regulating functional genes and biological processes. Its alternative splicing leads to various transcript variants encoding different isoforms. The spotlight has shifted towards the extensive discussion on tumors interplayed withHNF4α abnormalities. Aberrant HNF4α expression has emerged as sentinel markers of epigenetic shifts, casting reverberations upon downstream target genes and intricate signaling pathways, most notably with cancer. This review provides a comprehensive overview of HNF4α's involvement in tumor progression and metastasis, elucidating its role and underlying mechanisms.

Targeted Activation of HNF4α by AMPK Inhibits Apoptosis and Ameliorates Neurological Injury Caused by Cardiac Arrest in Rats

Previous studies have shown that AMPK plays an important role in cerebral ischemia-reperfusion injury by participating in apoptosis, but the exact mechanism and target of action remains unclear. This study aimed to investigate the protective mechanism of AMPK activation on brain injury secondary to cardiac arrest. HE, Nills and TUNEL assays were used to evaluate neuronal damage and apoptosis. The relationships between AMPK, HNF4α and apoptotic genes were verified by ChIP-seq, dual-luciferase and WB assays. The results showed that AMPK improved the 7-day memory function of rats, and reduced neuronal cell injury and apoptosis in the hippocampal CA1 region after ROSC, while the use of HNF4α inhibitor weakened the protective effect of AMPK. Further research found that AMPK positively regulated the expression of HNF4α, and AMPK could promote the expression of Bcl-2 and inhibit the expression of Bax and Cleaved-Caspase 3. In vitro experiments showed that AMPK ameliorated neuronal injury by inhibiting apoptosis through the activation of HNF4α. Combined with ChIP-seq, JASPAR analysis and Dual-luciferase assay, the binding site of HNF4α to the upstream promoter of Bcl-2 was found. Taken together, AMPK attenuates brain injury after CA by activating HNF4α to target Bcl-2 to inhibit apoptosis.

CHD5 inhibits metastasis of neuroblastoma

CHD5, a tumor suppressor at 1p36, is frequently lost or silenced in poor prognosis neuroblastoma (NB) and many adult cancers. The role of CHD5 in metastasis is unknown. We confirm that low expression of CHD5 is associated with stage 4 NB. Forced expression of CHD5 in NB cell lines with 1p loss inhibited key aspects of the metastatic cascade in vitro: anchorage-independent growth, migration, and invasion. In vivo, formation of bone marrow and liver metastases developing from intravenously injected NB cells was delayed and decreased by forced CHD5 expression. Genome-wide mRNA sequencing revealed reduction of genes and gene sets associated with metastasis when CHD5 was overexpressed. Known metastasis-suppressing genes preferentially upregulated in CHD5-overexpressing NB cells included PLCL1. In patient NB, low expression of PLCL1was associated with metastatic disease and poor survival. Knockdown of PLCL1 and of p53 in IMR5 NB cells overexpressing CHD5 reversed CHD5-induced inhibition of invasion and migration in vitro. In summary, CHD5 is a metastasis suppressor in NB.

Activatable Second Near-Infrared Fluorescent Probes: A New Accurate Diagnosis Strategy for Diseases

Recently, second near-infrared (NIR-II) fluorescent imaging has been widely applied in biomedical diagnosis, due to its high spatiotemporal resolution and deep tissue penetration. In contrast to the "always on" NIR-II fluorescent probes, the activatable NIR-II fluorescent probes have specific targeting to biological tissues, showing a higher imaging signal-to-background ratio and a lower detection limit. Therefore, it is of great significance to utilize disease-associated endogenous stimuli (such as pH values, enzyme existence, hypoxia condition and so on) to activate the NIR-II probes and achieve switchable fluorescent signals for specific deep bioimaging. This review introduces recent strategies and mechanisms for activatable NIR-II fluorescent probes and their applications in biosensing and bioimaging. Moreover, the potential challenges and perspectives of activatable NIR-II fluorescent probes are also discussed.

Diagnostic utility of the combined use of HNF4A and GATA3 in distinction between primary and metastatic breast and gastric carcinomas

Sometimes the distinction between gastric adenocarcinomas and breast carcinomas can be challenging. Hepatocyte nuclear factor 4-alpha (HNF4A) has been suggested as a potential marker in these cases. The aim of the present work was to evaluate the role of the combined use of HNF4A and GATA3 as immunohistochemical markers in distinction between primary and metastatic breast and gastric carcinomas. This retrospective study was conducted on (81) cases divided into four groups of cohorts: primary BC (cohort I, n = 25), primary GC (cohort II, n = 23), and metastases derived from both types of tumors designated as metastasis derived from BC (cohort III-A, n = 17) and metastasis derived from GC (cohort III-B, n = 16). We performed immunohistochemistry analysis of HNF4A and GATA3 in all (81) cases. HNF4A expression was seen in 22 of 23 primary gastric adenocarcinomas and was absent in all 25 primary breast carcinomas (sensitivity 95.7%, specificity 100%). HNF4A was seen in 15 of 16 metastatic gastric adenocarcinomas and was absent in all 17 metastatic breast carcinomas (sensitivity 93.8%, specificity 100%). GATA3 showed 92 and 88% sensitivity, and 95.7 and 100% specificity for primary breast carcinomas and metastatic breast carcinomas, respectively. Our data confirmed the potential utility of HNF4A as a diagnostic marker and can be used as an adjunct to GATA3 as an immunohistochemical panel to differentiate between breast and gastric carcinomas.

Targeting the crosstalk between canonical Wnt/β-catenin and inflammatory signaling cascades: A novel strategy for cancer prevention and therapy

Emerging scientific evidence indicates that inflammation is a critical component of tumor promotion and progression. Most cancers originate from sites of chronic irritation, infections and inflammation, underscoring that the tumor microenvironment is largely orchestrated by inflammatory cells and pro-inflammatory molecules. These inflammatory components are intimately involved in neoplastic processes which foster proliferation, survival, invasion, and migration, making inflammation the primary target for cancer prevention and treatment. The influence of inflammation and the immune system on the progression and development of cancer has recently gained immense interest. The Wnt/β-catenin signaling pathway, an evolutionarily conserved signaling strategy, has a critical role in regulating tissue development. It has been implicated as a major player in cancer development and progression with its regulatory role on inflammatory cascades. Many naturally-occurring and small synthetic molecules endowed with inherent anti-inflammatory properties inhibit this aberrant signaling pathway, making them a promising class of compounds in the fight against inflammatory cancers. This article analyzes available scientific evidence and suggests a crosslink between Wnt/β-catenin signaling and inflammatory pathways in inflammatory cancers, especially breast, gastrointestinal, endometrial, and ovarian cancer. We also highlight emerging experimental findings that numerous anti-inflammatory synthetic and natural compounds target the crosslink between Wnt/β-catenin pathway and inflammatory cascades to achieve cancer prevention and intervention. Current challenges, limitations, and future directions of research are also discussed.

Controversial roles of hepatocyte nuclear receptor 4 α on tumorigenesis

Hepatocyte nuclear receptor 4 α (HNF4α) is known to be a master transcription regulator of gene expression in multiple biological processes, particularly in liver development and liver function. To date, the function of HNF4α in human cancers has been widely investigated; however, the critical roles of HNF4α in tumorigenesis remain unclear. Numerous controversies exist, even in studies from different research groups but on the same type of cancer. In the present review, the critical roles of HNF4α in tumorigenesis will be summarized and discussed. Furthermore, HNF4α expression profile and alterations will be examined by pan-cancer analysis through bioinformatics, in order to provide a better understanding of the functional roles of this gene in human cancers.

Hepatocyte nuclear factor 4α and cancer-related cell signaling pathways: a promising insight into cancer treatment

Hepatocyte nuclear factor 4α (HNF4α), a member of the nuclear receptor superfamily, is described as a protein that binds to the promoters of specific genes. It controls the expression of functional genes and is also involved in the regulation of numerous cellular processes. A large number of studies have demonstrated that HNF4α is involved in many human malignancies. Abnormal expression of HNF4α is emerging as a critical factor in cancer cell proliferation, apoptosis, invasion, dedifferentiation, and metastasis. In this review, we present emerging insights into the roles of HNF4α in the occurrence, progression, and treatment of cancer; reveal various mechanisms of HNF4α in cancer (e.g., the Wnt/β-catenin, nuclear factor-κB, signal transducer and activator of transcription 3, and transforming growth factor β signaling pathways); and highlight potential clinical uses of HNF4α as a biomarker and therapeutic target for cancer.

Basic research in childhood cancer: Progress and future directions in China

Childhood cancer is a leading cause of death in children. Some childhood cancers have a particularly high mortality rate. Following the World Health Organization's emphasis on child health, most governments worldwide have taken measures to facilitate childhood cancer research. Thus, the scientific community is showing increasing interest in this area. Chinese government has prominence in building a system for the diagnosis and treatment of childhood cancer, thereby promoting the development of childhood cancer research. This review summarizes the research progress, challenges, and perspectives in childhood cancer, and the increasing contributions of National Natural Science Foundation of China (NSFC) in the past decade (2008-2018).

Long Noncoding RNA NHEG1 Drives β-Catenin Transactivation and Neuroblastoma Progression through Interacting with DDX5

Recent studies suggest that long noncoding RNAs (lncRNAs) play essential roles in tumor progression. However, the functional roles and underlying mechanisms of lncRNAs in neuroblastoma (NB), the most common malignant solid tumor in pediatric population, still remain elusive. Herein, through integrating analysis of a public RNA sequencing dataset, neuroblastoma highly expressed 1 (NHEG1) was identified as a risk-associated lncRNA, contributing to an unfavorable outcome of NB. Depletion of NHEG1 led to facilitated differentiation and decreased growth and aggressiveness of NB cells. Mechanistically, NHEG1 bound to and stabilized DEAD-box helicase 5 (DDX5) protein through repressing proteasome-mediated degradation, resulting in β-catenin transactivation that altered target gene expression associated with NB progression. We further determined a lymphoid enhancer binding factor 1 (LEF1)/transcription factor 7-like 2 (TCF7L2)/NHEG1/DDX5/β-catenin axis with a positive feedback loop and demonstrated that NHEG1 harbored oncogenic properties via its interplay with DDX5. Administration of small interfering RNAs against NHEG1 or DDX5 reduced tumor growth and prolonged survival of nude mice bearing xenografts. High NHEG1 or DDX5 expression was associated with poor survival of NB patients. These results indicate that lncRNA NHEG1 exhibits oncogenic activity that affects NB progression via stabilizing the DDX5 protein, which might serve as a potential therapeutic target for NB.

miR-34a inhibits proliferation, migration and invasion of paediatric neuroblastoma cells via targeting HNF4α

Objective: To investigate the potential mechanism of microRNA-34a (miR-34a) on proliferation, migration and invasion of paediatric neuroblastoma cells. Methods: The expression of miR-34a and hepatocyte nuclear factor 4α (HNF4α) in paediatric neuroblastoma tissues were detected by RT-q PCR and Western blot, respectively. Cell proliferation, migration, invasion and the expression of matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 14 (MMP-14) after transfection of miR-34a mimics or HNF4α siRNA into SH-SY5Y cells were detected by MTT assay, Transwell assay and Western blot assay, respectively. The target relationship between miR-34a and HNF4α was verified by TargetScan online prediction and dual-luciferase assay. Cell proliferation, migration and invasion of SH-SY5Y cells after overexpression of miR-34a and HNF4α were detected. Results: The expression level of miR-34a was decreased (p < .05) while the expression level of HNF4α was increased (p < .05) in paediatric neuroblastoma tissues. Over- expression of Mi-34a or knockdown of HNF4α in SH-SY5Y cells could lead to a decreased of cell proliferation, migration, invasion and the expression of MMP-2 and MMP-14 (p < .05). The results of TargetScan online prediction and dual-luciferase assay indicted that HNF4α was a potential target gene for miR-34a. Overexpression of HNF4α could reverse the inhibition of miR-34a on proliferation, migration and invasion of SH-SY5Y cells. Conclusion: The expression of miR-34a was down-regulated in paediatric neuroblastoma tissues, and overexpression of miR-34a could inhibit proliferation, migration and invasion of SH-SY5Y cells by targeting HNF4α.

Nuclear receptor HNF4α performs a tumor suppressor function in prostate cancer via its induction of p21-driven cellular senescence

Hepatocyte nuclear factor 4α (HNF4α, NR2A1) is a highly conserved member of the nuclear receptor superfamily. Recent advances reveal that it is a key transcriptional regulator of genes, broadly involved in xenobiotic and drug metabolism and also cancers of gastrointestinal tract. However, the exact functional roles of HNF4α in prostate cancer progression are still not fully understood. In this study, we determined the functional significance of HNF4α in prostate cancer. Our results showed that HNF4α exhibited a reduced expression pattern in clinical prostate cancer tissues, prostate cancer cell lines and xenograft model of castration-relapse prostate cancer. Stable HNF4α knockdown not only could promote cell proliferation and suppress doxorubicin (Dox)-induced cellular senescence in prostate cancer cells, but also confer resistance to paclitaxel treatment and enhance colony formation capacity and in vivo tumorigenicity of prostate cancer cells. On the contrary, ectopic overexpression of HNF4α could significantly inhibit the cell proliferation of prostate cancer cells, induce cell-cycle arrest at G₂/M phase and trigger the cellular senescence in prostate cancer cells by activation of p21 signal pathway in a p53-independent manner via its direct transactivation of CDKN1A. Together, our results show that HNF4α performs a tumor suppressor function in prostate cancer via a mechanism of p21-driven cellular senescence.

Association between HNF4A mutations and bleeding complications in patients with stable international normalized ratio

OBJECTIVES

This study aimed to determine the association between hepatocyte nuclear factor 4 alpha (HNF4A) polymorphisms and bleeding complications in patients on warfarin with international normalized ratios between 2.0 and 3.0 after cardiac valve replacement.

METHODS

Nineteen single nucleotide polymorphisms of HNF4A in addition to VKORC1 rs9934438 and CYP2C9 rs1057910 were analyzed. Univariate and multivariate analyses were conducted to evaluate associations between genetic polymorphisms and bleeding risk. Attributable risk and number needed to genotype (NNG) were calculated to assess clinical value of genotyping.

RESULTS

Of 142 patients, 21 experienced bleeding complications. Multivariate logistic regression analysis was conducted using factors with P <0.1 in univariate analysis. Multivariate analysis showed that patients with the CC genotype of rs6130615 had an 8.4-fold increased risk of bleeding, compared with patients with the T allele. Attributable risk and NNG were 88.1% and 32.2, respectively. Patients with the TT genotype of rs3212191 had a 3.8-fold increased risk of bleeding, compared with C allele carriers, while patients with variant-type homozygotes for rs1884613 showed an 8.7-fold higher bleeding complication than C allele carriers. The attributable risk/NNG of rs3212191 and rs1884613 were 73.4%/17.6 and 88.5%/22.8, respectively. Among comorbidities, atrial fibrillation was the only significant risk factor for bleeding complications.

CONCLUSION

Bleeding complications during warfarin therapy in patients with mechanical heart valves were associated with HNF4A polymorphisms and atrial fibrillation.

Incompatibility of the circadian protein BMAL1 and HNF4α in hepatocellular carcinoma

Hepatocyte nuclear factor 4 alpha (HNF4α) is a master regulator of liver-specific gene expression with potent tumor suppressor activity, yet many liver tumors express HNF4α. This study reveals that P1-HNF4α, the predominant isoform expressed in the adult liver, inhibits expression of tumor promoting genes in a circadian manner. In contrast, an additional isoform of HNF4α, driven by an alternative promoter (P2-HNF4α), is induced in HNF4α-positive human hepatocellular carcinoma (HCC). P2-HNF4α represses the circadian clock gene ARNTL (BMAL1), which is robustly expressed in healthy hepatocytes, and causes nuclear to cytoplasmic re-localization of P1-HNF4α. We reveal mechanisms underlying the incompatibility of BMAL1 and P2-HNF4α in HCC, and demonstrate that forced expression of BMAL1 in HNF4α-positive HCC prevents the growth of tumors in vivo. These data suggest that manipulation of the circadian clock in HNF4α-positive HCC could be a tractable strategy to inhibit tumor growth and progression in the liver.

Berberine Attenuated Proliferation, Invasion and Migration by Targeting the AMPK/HNF4α/WNT5A Pathway in Gastric Carcinoma

Background: Recent epidemiologic studies have found that patients with diabetes have a higher risk of gastric cancer (GC), and the long-term use of metformin is associated with a lower risk of gastric cancer. It is believed that blocking tumor energy metabolic alterations is now emerging as a new therapeutic approach of cancer. Berberine, a natural isoquinoline alkaloid, could modulate lipid metabolism and glucose homeostasis by regulating the expression of HNF4α in many metabolic diseases. Here, we investigated the effect of Berberine on GC and its possible molecular mechanism through targeting HNF4α.

Methods and Results: (1) AGS and SGC7901 gastric cancer cells were treated with Berberine (BBR). We found that in AGS and SGC7901 cell, BBR inhibited cell proliferation in a time- and dose-dependent manner through downregulating C-myc. BBR also induced G₀-G₁ phase arrest with the decreased expression of cyclin D1. Moreover, BBR attenuated the migration and invasion by downregulating MMP-3. (2) The lentivirus infection was used to silence the expression of HNF4α in SGC7901 cell. The results demonstrated that the knockdown of HNF4α in SGC7901 slowed cells proliferation, induced S phase arrest and dramatically attenuated gastric cancer cells’ metastasis and invasion. (3) We performed GC cells perturbation experiments through BI6015 (an HNF4α antagonist), AICAR (an AMPK activator), Compound C (AMPK-kinase inhibitor), metformin and BBR. Our findings indicated that BBR downregulated HNF4α while upregulating p-AMPK. Moreover, the inhibition of HNF4α by BBR was AMPK dependent. (4) Then the LV-HNF4α-RNAi SGC7901 cell model was used to detect the downstream of HNF4α in vitro. The results showed that the knockdown of HNF4α significantly decreased WNT5A and cytoplasmic β-catenin, but increased E-cadherin in vitro. Berberine also downregulated WNT5A and cytoplasmic β-catenin, the same as LV-HNF4α-RNAi and BI6015 in GC cells. (5) Finally, the SGC7901 and LV-HNF4α-RNAi SGC7901 mouse-xenograft model to evaluate the effect of BBR and HNF4α gene on GC tumor growth. The result illustrated that BBR and knockdown of HNF4α suppressed tumor growth in vivo, and BBR decreased HNF4α, WNT5A and cytoplasmic β-catenin levels, the same effect as HNF4α knockout in vivo.

Conclusion: BBR not only had proliferation inhibition effect, attenuated the invasion and migration on GC cell lines, but also suppressed the GC tumor growth in vivo. The anti-gastric cancer mechanism of BBR might be involved in AMPK-HNF4α-WNT5A signaling pathway. HNF4α antagonists, such as BBR, could be a promising anti-gastric cancer treatment supplement.

Ets-1 promoter-associated noncoding RNA regulates the NONO/ERG/Ets-1 axis to drive gastric cancer progression

Emerging studies have indicated the essential functions of long noncoding RNAs (lncRNAs) during cancer progression. However, whether lncRNAs contribute to the upregulation of v-ets erythroblastosis virus E26 oncogene homolog 1 (Ets-1), an established oncogenic protein facilitating tumor invasion and metastasis, in gastric cancer remains elusive. Herein, we identified Ets-1 promoter-associated noncoding RNA (pancEts-1) as a novel lncRNA associated with the gastric cancer progression via mining of publicly available datasets and rapid amplification of cDNA ends. RNA pull-down, RNA immunoprecipitation, in vitro binding, and RNA electrophoretic mobility shift assays indicated the binding of pancEts-1 to non-POU domain containing octamer binding (NONO) protein. Mechanistically, pancEts-1 facilitated the physical interaction between NONO and Ets related gene (ERG), resulting in increased ERG transactivation and transcription of Ets-1 associated with gastric cancer progression. In addition, pancEts-1 facilitated the growth and aggressiveness of gastric cancer cells via interacting with NONO. In gastric cancer tissues, pancEts-1, NONO, and ERG were upregulated and significantly correlated with Ets-1 levels. High levels of pancEts-1, NONO, ERG, or Ets-1 were respectively associated with poor survival of gastric cancer patients, whereas simultaneous expression of all of them (HR = 3.012, P = 0.105) was not an independent prognostic factor for predicting clinical outcome. Overall, these results demonstrate that lncRNA pancEts-1 exhibits oncogenic properties that drive the progression of gastric cancer via regulating the NONO/ERG/Ets-1 axis.

HPSE enhancer RNA promotes cancer progression through driving chromatin looping and regulating hnRNPU/p300/EGR1/HPSE axis

Recent studies reveal the emerging functions of enhancer RNAs (eRNAs) in gene expression. However, the roles of eRNAs in regulating the expression of heparanase (HPSE), an established endo-β-D-glucuronidase essential for cancer invasion and metastasis, still remain elusive. Herein, through comprehensive analysis of publically available FANTOM5 expression atlas and chromatin interaction dataset, we identified a super enhancer and its derived eRNA facilitating the HPSE expression (HPSE eRNA) in cancers. Gain-of-function and loss-of-function experiments indicated that HPSE eRNA facilitated the in vitro and in vivo tumorigenesis and aggressiveness of cancer cells. Mechanistically, as a p300-regulated nuclear noncoding RNA, HPSE eRNA bond to heterogeneous nuclear ribonucleoprotein U (hnRNPU) to facilitate its interaction with p300 and their enrichment on super enhancer, resulting in chromatin looping between super enhancer and HPSE promoter, p300-mediated transactivation of transcription factor early growth response 1 (EGR1), and subsequent elevation of HPSE expression. In addition, rescue studies in HPSE overexpressing or silencing cancer cells indicated that HPSE eRNA exerted oncogenic properties via driving HPSE expression. In clinical cancer tissues, HPSE eRNA was highly expressed and positively correlated with HPSE levels, and served as an independent prognostic factor for poor outcome of cancer patients. Therefore, these findings indicate that as a novel noncoding RNA, HPSE eRNA promotes cancer progression through driving chromatin looping and regulating hnRNPU/p300/EGR1/HPSE axis.

miRNA-337-3p inhibits gastric cancer progression through repressing myeloid zinc finger 1-facilitated expression of matrix metalloproteinase 14

Matrix metalloproteinase 14 (MMP-14), a membrane-anchored MMP that promotes the tumorigenesis and aggressiveness, is highly expressed in gastric cancer. However, the transcriptional regulators of MMP-14 expression in gastric cancer still remain largely unknown. In this study, through mining computational algorithm programs and chromatin immunoprecipitation datasets, we identified adjacent binding sites of myeloid zinc finger 1 (MZF1) and miRNA-337-3p (miR-337-3p) within the MMP-14 promoter. We demonstrated that MZF1 directly bound to the MMP-14 promoter to facilitate its nascent transcription and expression in gastric cancer cell lines. In contrast, endogenous miR-337-3p suppressed the MMP-14 expression through recognizing its binding site within MMP-14 promoter. Mechanistically, miR-337-3p repressed the binding of MZF1 to MMP-14 promoter via recruiting Argonaute 2 and inducing repressive chromatin remodeling. Gain- and loss-of-function studies demonstrated that miR-337-3p suppressed the growth, invasion, metastasis, and angiogenesis of gastric cancer cells in vitro and in vivo through repressing MZF1-facilitated MMP-14 expression. In clinical specimens and cell lines of gastric cancer, MZF1 was highly expressed and positively correlated with MMP-14 expression. Meanwhile, miR-337-3p was under-expressed and inversely correlated with MMP-14 levels. miR-337-3p was an independent prognostic factor for favorable outcome of gastric cancer, and patients with high MZF1 or MMP-14 expression had lower survival probability. Taken together, these data indicate that miR-337-3p directly binds to the MMP-14 promoter to repress MZF1-facilitatd MMP-14 expression, thus suppressing the progression of gastric cancer.

microRNA-558 facilitates the expression of hypoxia-inducible factor 2 alpha through binding to 5'-untranslated region in neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood. Our previous studies have shown that hypoxia-inducible factor 2 alpha (HIF-2α), one member of the bHLH-PAS transcription factor family, facilitates the progression of NB under non-hypoxic conditions. However, the mechanisms underlying HIF-2α expression in NB still remain largely unknown. Herein, through analyzing the computational algorithm programs, we identified microRNA-558 (miR-558) as a crucial regulator of HIF-2α expression in NB. We demonstrated that miR-558 promoted the expression of HIF-2α at translational levels in NB cells through recruiting Argonaute 2 (AGO2). Mechanistically, miR-558 directly bound with its complementary site within 5′-untranslated region (5′-UTR) to facilitate the binding of AGO2 to eukaryotic translation initiation factor 4E (eIF4E) binding protein 1, resulting in increased eIF4E enrichment and HIF-2α translation. In addition, miR-558 promoted the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo, and these biological features were rescued by knockdown of AGO2, eIF4E, or HIF-2α. In clinical NB specimens, miR-558, AGO2, and eIF4E were highly expressed and positively correlated with HIF-2α expression. Patients with high miR-558, HIF-2α, AGO2, or eIF4E levels had lower survival probability. Taken together, these results demonstrate that miR-558 facilitates the expression of HIF-2α through bindingto its 5′-UTR, thus promoting the tumorigenesis and aggressiveness of NB.

Risk-Associated Long Noncoding RNA FOXD3-AS1 Inhibits Neuroblastoma Progression by Repressing PARP1-Mediated Activation of CTCF

Neuroblastoma (NB) is the most common extracranial tumor in childhood. Recent studies have implicated the emerging roles of long noncoding RNAs (lncRNAs) in tumorigenesis and aggressiveness. However, the functions and targets of risk-associated lncRNAs in NB progression still remain to be determined. Herein, through mining of public microarray datasets, we identify lncRNA forkhead box D3 antisense RNA 1 (FOXD3-AS1) as an independent prognostic marker for favorable outcome of NB patients. FOXD3-AS1 is downregulated in NB tissues and cell lines, and ectopic expression of FOXD3-AS1 induces neuronal differentiation and decreases the aggressiveness of NB cells in vitro and in vivo. Mechanistically, as a nuclear lncRNA, FOXD3-AS1 interacts with poly(ADP-ribose) polymerase 1 (PARP1) to inhibit the poly(ADP-ribosyl)ation and activation of CCCTC-binding factor (CTCF), resulting in derepressed expression of downstream tumor-suppressive genes. Rescue experiments indicate that FOXD3-AS1 harbors tumor-suppressive properties by inhibiting the oncogenic roles of PARP1 or CTCF and plays crucial roles in all-trans-retinoic-acid-mediated therapeutic effects on NB. Administration of FOXD3-AS1 construct or siRNAs against PARP1 or CTCF reduces the tumor growth and prolongs the survival of nude mice. These findings suggest that as a risk-associated lncRNA, FOXD3-AS1 inhibits the progression of NB through repressing PARP1-mediated CTCF activation.

TGF-β inhibits alveolar protein transport by promoting shedding, regulated intramembrane proteolysis, and transcriptional downregulation of megalin

Disruption of the alveolar-capillary barrier is a hallmark of acute respiratory distress syndrome (ARDS) that leads to the accumulation of protein-rich edema in the alveolar space, often resulting in comparable protein concentrations in alveolar edema and plasma and causing deleterious remodeling. Patients who survive ARDS have approximately three times lower protein concentrations in the alveolar edema than nonsurvivors; thus the ability to remove excess protein from the alveolar space may be critical for a positive outcome. We have recently shown that clearance of albumin from the alveolar space is mediated by megalin, a 600-kDa transmembrane endocytic receptor and member of the low-density lipoprotein receptor superfamily. In the currents study, we investigate the molecular mechanisms by which transforming growth factor-β (TGF-β), a key molecule of ARDS pathogenesis, drives downregulation of megalin expression and function. TGF-β treatment led to shedding and regulated intramembrane proteolysis of megalin at the cell surface and to a subsequent increase in intracellular megalin COOH-terminal fragment abundance resulting in transcriptional downregulation of megalin. Activity of classical protein kinase C enzymes and γ-secretase was required for the TGF-β-induced megalin downregulation. Furthermore, TGF-β-induced shedding of megalin was mediated by matrix metalloproteinases (MMPs)-2, -9, and -14. Silencing of either of these MMPs stabilized megalin at the cell surface after TGF-β treatment and restored normal albumin transport. Moreover, a direct interaction of megalin with MMP-2 and -14 was demonstrated, suggesting that these MMPs may function as novel sheddases of megalin. Further understanding of these mechanisms may lead to novel therapeutic approaches for the treatment of ARDS.

HNF4A expression as a potential diagnostic tool to discriminate primary gastric cancer from breast cancer metastasis in a Brazilian cohort

BACKGROUND

Among the many challenges in cancer diagnosis is the early distinction between metastatic cancer and a secondary tumor. This difficulty stems from the lack of markers that offer high sensitivity and specificity and can be easily applied in routine laboratory work. An example of this challenge is distinguishing gastric metastases originating from breast cancer from a gastric primary tumor. Hepatocyte nuclear factor 4 alpha (HNF4A) has been suggested as a potential marker in these cases. The aim of this study was to analyze the expression of HNF4A, estrogen receptor (ER), progesterone receptor (PR) and gross cystic disease fluid protein 15 (GCDFP-15) in a Brazilian cohort.

METHODS

We performed immunohistochemistry analysis of HNF4A, ER, PR and GCDFP-15 in 126 patients divided into three cohorts: primary breast cancer, primary gastric cancer and both types of tumors.

RESULTS

Our data confirmed the sensitivity and specificity of the HNF4A marker compared to other currently used clinical markers.

CONCLUSION

HNF4A alone could be a gold standard marker for distinguishing primary gastric cancer from breast metastasis, thus validating its potential clinical use, especially in populations with high genetic diversity.

Inhibiting the SUMO Pathway Represses the Cancer Stem Cell Population in Breast and Colorectal Carcinomas

Many solid cancers have an expanded CD44^+/hi/CD24^−/low cancer stem cell (CSC) population, which are relatively chemoresistant and drive recurrence and metastasis. Achieving a more durable response requires the development of therapies that specifically target CSCs. Recent evidence indicated that inhibiting the SUMO pathway repressed tumor growth and invasiveness, although the mechanism has yet to be clarified. Here, we demonstrate that inhibition of the SUMO pathway repressed MMP14 and CD44 with a concomitant reduction in cell invasiveness and functional loss of CSCs in basal breast cancer. Similar effects were demonstrated with a panel of E1 and E3 SUMO inhibitors. Identical results were obtained in a colorectal cancer cell line and primary colon cancer cells. In both breast and colon cancer, SUMO-unconjugated TFAP2A mediated the effects of SUMO inhibition. These data support the development of SUMO inhibitors as an approach to specifically target the CSC population in breast and colorectal cancer.

•

Sumoylation regulates CD44 and MMP14 expression in basal breast and colon cancer

•

SUMO inhibition clears cancer stem cells, repressing invasiveness and tumor growth

•

Anacardic acid functions as a SUMO inhibitor to repress cancer stem cells

•

TFAP2A mediates anti-tumor effects of SUMO inhibition in breast and colon cancers

miRNA-337-3p suppresses neuroblastoma progression by repressing the transcription of matrix metalloproteinase 14

Recent evidence shows the emerging roles of endogenous microRNAs (miRNAs) in repressing gene transcription. However, the miRNAs inhibiting the transcription of matrix metalloproteinase 14 (MMP-14), a membrane-anchored MMP crucial for the tumorigenesis and aggressiveness, still remain largely unknown. In this study, through mining computational algorithm program and genome-wide Argonaute profiling dataset, we identified one binding site of miRNA-337-3p (miR-337-3p) within the MMP-14 promoter. We demonstrated that miR-337-3p was under-expressed and inversely correlated with MMP-14 expression in clinical specimens and cell lines of neuroblastoma (NB), the most common extracranial solid tumor in childhood. Patients with high miR-337-3p expression had greater survival probability. miR-337-3p suppressed the promoter activity, nascent transcription, and expression of MMP-14, resulting in decreased levels of vascular endothelial growth factor, in cultured NB cell lines. Mechanistically, miR-337-3p recognized its binding site and recruited Argonaute 2 to facilitate the enrichment of repressive epigenetic markers and decrease the binding of RNA polymerase II and specificity protein 1 on the MMP-14 promoter. Gain- and loss-of-function studies demonstrated that miR-337-3p suppressed the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. In addition, restoration of MMP-14 expression rescued the NB cells from changes in these biological features. Taken together, these data indicate that miR-337-3p directly binds the MMP-14 promoter to repress its transcription, thus suppressing the progression of NB.

Smad4 suppresses the tumorigenesis and aggressiveness of neuroblastoma through repressing the expression of heparanase

Heparanase (HPSE) is the only endo-β-D-glucuronidase that is correlated with the progression of neuroblastoma (NB), the most common extracranial malignancy in childhood. However, the mechanisms underlying HPSE expression in NB still remain largely unknown. Herein, through analyzing cis-regulatory elements and mining public microarray datasets, we identified SMAD family member 4 (Smad4) as a crucial transcription regulator of HPSE in NB. We demonstrated that Smad4 repressed the HPSE expression at the transcriptional levels in NB cells. Mechanistically, Smad4 suppressed the HPSE expression through directly binding to its promoter and repressing the lymphoid enhancer binding factor 1 (LEF1)-facilitated transcription of HPSE via physical interaction. Gain- and loss-of-function studies demonstrated that Smad4 inhibited the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. Restoration of HPSE expression prevented the NB cells from changes in these biological features induced by Smad4. In clinical NB specimens, Smad4 was under-expressed and inversely correlated with HPSE levels, while LEF1 was highly expressed and positively correlated with HPSE expression. Patients with high Smad4 expression, low LEF1 or HPSE levels had greater survival probability. These results demonstrate that Smad4 suppresses the tumorigenesis and aggressiveness of NB through repressing the HPSE expression.

CTCF cooperates with noncoding RNA MYCNOS to promote neuroblastoma progression through facilitating MYCN expression

Previous studies have indicated the important roles of MYCN in tumorigenesis and progression of neuroblastoma (NB), the most common extracranial solid tumor derived from neural crest in childhood. However, the regulatory mechanisms of MYCN expression in NB still remain largely unknown. In this study, through mining public microarray databases and analyzing the cis-regulatory elements and chromatin immunoprecipitation data sets, we identified CCCTC-binding factor (CTCF) as a crucial transcription factor facilitating the MYCN expression in NB. RNA immunoprecipitation, RNA electrophoretic mobility shift assay, RNA pull down and in vitro binding assay indicated the physical interaction between CTCF and MYCN opposite strand (MYCNOS), a natural noncoding RNA surrounding the MYNC promoter. Gain- and loss-of-function studies revealed that MYCNOS facilitated the recruitment of CTCF to its binding sites within the MYCN promoter to induce chromatin remodeling, resulting in enhanced MYCN levels and altered downstream gene expression, in cultured NB cell lines. CTCF cooperated with MYCNOS to suppress the differentiation and promote the growth, invasion and metastasis of NB cells in vitro and in vivo. In clinical NB tissues and cell lines, CTCF and MYCNOS were upregulated and positively correlated with MYCN expression. CTCF was an independent prognostic factor for unfavorable outcome of NB, and patients with high MYCNOS expression had lower survival probability. Taken together, these results demonstrate that CTCF cooperates with noncoding RNA MYCNOS to exhibit oncogenic activity that affects the aggressiveness and progression of NB through transcriptional upregulation of MYCN.

Role of the LKB1/AMPK pathway in tumor invasion and metastasis of cancer cells (Review)

Liver kinase B1 (LKB1), also known as serine/threo-nine kinase 11 (STK11), is a tumor suppressor that is inactivated in Peutz-Jeghers familial cancer syndrome. LKB1 phosphorylates and activates AMP-activated protein kinase (AMPK), which negatively regulates cancer cell proliferation and metabolism. However, recent evidence demonstrates that the LKB1/AMPK pathway is involved in the process of tumor invasion and migration, which is an important hallmark of carcinoma progression to higher pathological grades of malignancy. This review focuses on the function of the LKB1/AMPK pathway in the invasion and migration of cancer cells and provides an overview of therapeutic strategies aimed at this pathway in malignant tumors.

miRNA-584-5p exerts tumor suppressive functions in human neuroblastoma through repressing transcription of matrix metalloproteinase 14

Matrix metalloproteinase 14 (MMP-14) is a membrane-anchored MMP crucial for tumorigenesis and aggressiveness, and is highly expressed in neuroblastoma (NB), the most common extracranial solid tumor in childhood. Recent evidence shows the emerging roles of endogenous promoter-targeting microRNAs (miRNAs) in regulating gene transcription. However, the roles of miRNAs in the transcription of MMP-14 still remain largely unknown. In this study, through mining computational algorithm program and Argonaute-chromosome interaction dataset, we identified one binding site of miRNA-584-5p (miR-584-5p) within the MMP-14 promoter. In NB tissues, miR-584-5p was under-expressed and inversely correlated with MMP-14 expression, and was an independent prognostic factor for favorable outcome of patients. miR-584-5p precursor attenuated the expression of MMP-14 in a Dicer-dependent manner, resulting in decreased levels of vascular endothelial growth factor, in cultured NB cell lines. In addition, miR-584-5p suppressed the promoter activity of MMP-14, and mutation of miR-584-5p binding site abolished these effects. Mechanistically, miR-584-5p recruited Argonaute 2 to facilitate the enrichment of enhancer of zeste homolog 2, histone H3 lysine 27 trimethylation, and histone H3 lysine 9 dimethylation on MMP-14 promoter in NB cells, which was abolished by repressing the miR-584-5p-promoter interaction. Gain- and loss-of-function studies demonstrated that miR-584-5p suppressed the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. Moreover, restoration of MMP-14 expression rescued the NB cells from changes in these biological features. Taken together, these results indicate that promoter-targeting miR-584-5p exerts tumor suppressive functions in NB through repressing the transcription of MMP-14.