Deregulated AJAP1/β-catenin/ZEB1 signaling promotes hepatocellular carcinoma carcinogenesis and metastasis

Methylation-regulated tumor suppressor gene PDE7B promotes HCC invasion and metastasis through the PI3K/AKT signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) has a high mortality rate, and the mechanisms underlying tumor development and progression remain unclear. However, inactivated tumor suppressor genes might play key roles. DNA methylation is a critical regulatory mechanism for inactivating tumor suppressor genes in HCC. Therefore, this study investigated methylation-related tumor suppressors in HCC to identify potential biomarkers and therapeutic targets.

METHODS

We assessed genome-wide DNA methylation in HCC using whole genome bisulfite sequencing (WGBS) and RNA sequencing, respectively, and identified the differential expression of methylation-related genes, and finally screened phosphodiesterase 7B (PDE7B) for the study. The correlation between PDE7B expression and clinical features was then assessed. We then analyzed the changes of PDE7B expression in HCC cells before and after DNA methyltransferase inhibitor treatment by MassArray nucleic acid mass spectrometry. Furthermore, HCC cell lines overexpressing PDE7B were constructed to investigate its effect on HCC cell function. Finally, GO and KEGG were applied for the enrichment analysis of PDE7B-related pathways, and their effects on the expression of pathway proteins and EMT-related factors in HCC cells were preliminarily explored.

RESULTS

HCC exhibited a genome-wide hypomethylation pattern. We screened 713 hypomethylated and 362 hypermethylated mCG regions in HCC and adjacent normal tissues. GO analysis showed that the main molecular functions of hypermethylation and hypomethylation were "DNA-binding transcriptional activator activity" and "structural component of ribosomes", respectively, whereas KEGG analysis showed that they were enriched in "bile secretion" and "Ras-associated protein-1 (Rap1) signaling pathway", respectively. PDE7B expression was significantly down-regulated in HCC tissues, and this low expression was negatively correlated with recurrence and prognosis of HCC. In addition, DNA methylation regulates PDE7B expression in HCC. On the contrary, overexpression of PDE7B inhibited tumor proliferation and metastasis in vitro. In addition, PDE7B-related genes were mainly enriched in the PI3K/ATK signaling pathway, and PDE7B overexpression inhibited the progression of PI3K/ATK signaling pathway-related proteins and EMT.

CONCLUSION

PDE7B expression in HCC may be regulated by promoter methylation. PDE7B can regulate the EMT process in HCC cells through the PI3K/AKT pathway, which in turn affects HCC metastasis and invasion.

A novel hypoxia-stimulated lncRNA HIF1A-AS3 binds with YBX1 to promote ovarian cancer tumorigenesis by suppressing p21 and AJAP1 transcription

Hypoxia is characteristic of the ovarian tumor (OC) microenvironment and profoundly affects tumorigenesis and therapeutic response. Long noncoding RNAs (lncRNAs) play various roles in tumor progression; however, the characteristics of lncRNAs in pathological responses of the OC microenvironment are not entirely understood. Through high-throughput sequencing, lncRNA expression in hypoxia (1% O2 ) and normoxia (21% O2 ) SKOV3 cells was explored and analyzed. The 5'- and 3'-rapid amplification of complementary DNA ends was used to detect the full length of the novel HIF1A-AS3 transcript. Real-time quantitative polymerase chain reaction was used to assess HIF1A-AS3 expression in OC cells and tissues. In vitro and in vivo evaluations of the biological functions of hypoxic HIF1A-AS3 were conducted. To clarify the underlying mechanisms of HIF1A-AS3 in hypoxic OC, a dual-luciferase assay, chromatin immunoprecipitation, RNA pull-down, RNA immunoprecipitation, and RNA-sequencing were used. We used high-throughput sequencing to investigate a novel lncRNA, HIF1A-AS3, as a hypoxic candidate significantly elevated in OC cells/tissues. HIF1A-AS3 was predominantly localized in the nucleus and promoted in vitro and in vivo OC growth and tumorigenesis. Hypoxia-inducible factor 1α bound to hypoxia response elements in the HIF1A-AS3 promoter region and stimulated its expression in hypoxia. Under hypoxia, HIF1A-AS3 directly integrated with Y-Box binding protein 1 and inhibited its ability to bind to the promoters of p21 and AJAP1 to repress their transcriptional activity, thereby promoting hypoxic OC progression. Our results revealed the crucial role and mechanism of the novel hypoxic HIF1A-AS3 in the oncogenesis of OC. The novel HIF1A-AS3 could be a crucial biomarker and therapeutic target for future OC treatments.

Based on disulfidptosis, revealing the prognostic and immunological characteristics of renal cell carcinoma with tumor thrombus of vena cava and identifying potential therapeutic target AJAP1

BACKGROUND

Patients with clear cell renal cell carcinoma (ccRCC) with venous tumor thrombus have a poor prognosis, high surgical risk, and lack of targeted therapeutic agents.

METHODS

Genes with consistent differential expression trends in tumor tissues and VTT groups were first screened, and then differential genes associated with disulfidptosis were found by correlation analysis. Subsequently, identifying ccRCC subtypes and constructing risk models to compare the differences in prognosis and the tumor microenvironment in different subgroups. Finally, constructing a nomogram to predict the prognosis of ccRCC and validate key gene expression levels in cells and tissues.

RESULTS

We screened 35 differential genes related to disulfidptosis and identified 4 ccRCC subtypes. Risk models were constructed based on the 13 genes, and the high-risk group had a higher abundance of immune cell infiltration, tumor mutational load, and microsatellite instability scores, predicting high sensitivity to immunotherapy. The 1-year AUC = 0.869 for predicting OS by nomogram has a high application value. The expression level of the key gene AJAP1 was low in both tumor cell lines and cancer tissues.

CONCLUSIONS

Our study not only constructed an accurate prognostic nomogram for ccRCC patients but also identified an AJAP1 biomarker as a potential biomarker for the disease.

Better safe than sorry-Whole-genome sequencing indicates that missense variants are significant in susceptibility to COVID-19

Undoubtedly, genetic factors play an important role in susceptibility and resistance to COVID-19. In this study, we conducted the GWAS analysis. Out of 15,489,173 SNPs, we identified 18,191 significant SNPs for severe and 11,799 SNPs for resistant phenotype, showing that a great number of loci were significant in different COVID-19 representations. The majority of variants were synonymous (60.56% for severe, 58.46% for resistant phenotype) or located in introns (55.77% for severe, 59.83% for resistant phenotype). We identified the most significant SNPs for a severe outcome (in AJAP1 intron) and for COVID resistance (in FIG4 intron). We found no missense variants with a potential causal function on resistance to COVID-19; however, two missense variants were determined as significant a severe phenotype (in PM20D1 and LRP4 exons). None of the aforementioned SNPs and missense variants found in this study have been previously associated with COVID-19.

Using Single-Cell RNA Sequencing and MicroRNA Targeting Data to Improve Colorectal Cancer Survival Prediction

Colorectal cancer has proven to be difficult to treat as it is the second leading cause of cancer death for both men and women worldwide. Recent work has shown the importance of microRNA (miRNA) in the progression and metastasis of colorectal cancer. Here, we develop a metric based on miRNA-gene target interactions, previously validated to be associated with colorectal cancer. We use this metric with a regularized Cox model to produce a small set of top-performing genes related to colon cancer. We show that using the miRNA metric and a Cox model led to a meaningful improvement in colon cancer survival prediction and correct patient risk stratification. We show that our approach outperforms existing methods and that the top genes identified by our process are implicated in NOTCH3 signaling and general metabolism pathways, which are essential to colon cancer progression.

Hypermethylation in the promoter region inhibits AJAP1 expression and activates the JAK/STAT pathway to promote prostate cancer cell migration and stem cell sphere formation

BACKGROUND

AJAP1 is down-regulated in multiple cancer types and plays a suppressive role in cancer progression. However, its molecular regulatory mechanism in prostate cancer has not been reported.

METHODS

Bioinformatics methods were employed to analyze AJAP1 expression in prostate cancer tissues and its association with TNM staging. MSP and qRT-PCR were used to quantify promoter methylation and AJAP1 expression after 5-aza-20-deoxycytidine (5-AzaC) treatment. Scratch healing assay and Transwell method were adopted to analyze the effects of aberrant AJAP1 expression, 5-AzaC and AG490 on cell migration and invasion. The levels of AJAP1 protein, EMT-related and JAK/STAT pathway-related proteins were determined by Western blot. The effects of AJAP1 aberrant expression and AG490 treatment on the sphere forming ability of prostate cancer cells were analyzed by sphere formation assay.

RESULTS

This study confirmed the significant down-regulation of AJAP1 expression in prostate cancer tissues and cells, and its negative correlation with TNM staging. 5-AzaC treatment led to a significant reduction of AJAP1 methylation level and a significant upregulation of AJAP1 expression, indicating that the methylation level of AJAP1 promoter may affect the expression of AJAP1. Cell function experiments found that overexpression or decreased methylation of AJAP1 inhibited epithelial mesenchymal transition (EMT), migration, and invasion, while silencing or increased methylation of AJAP1 had the opposite functions. JAK2/STAT3 pathway inhibiting assay found that inhibition of JAK2/STAT3 pathway significantly reduced EMT, cell migration, and stem cell sphere formation in prostate cancer.

SIGNIFICANCE

Therefore, investigating the influence of aberrant AJAP1 expression on functions of prostate cancer cells is conducive to our in-depth understanding of the mechanism of prostate cancer genesis and development.

LncRNA CEBPA-DT promotes liver cancer metastasis through DDR2/β-catenin activation via interacting with hnRNPC

BACKGROUND

Hepatocellular carcinoma (HCC) is the world's third leading cause of cancer-related death; due to the fast growth and high prevalence of tumor recurrence, the prognosis of HCC patients remains dismal. Long non-coding RNA CEBPA-DT, a divergent transcript of the CCAAT Enhancer Binding Protein Alpha (CEBPA) gene, has been shown to participate in multiple tumor progression. However, no research has established its cancer-promoting mechanism in HCC yet.

METHODS

CEBPA-DT was identified in human HCC tissues through RNA sequencing. The expression level of CEBPA-DT was assessed by quantitative real-time PCR. The biological effects of CEBPA-DT were evaluated in vitro and in vivo through gain or loss of function experiments. RNA fluorescence in situ hybridization (FISH), RNA immunoprecipitation (RIP) and RNA pull-down assays were applied to investigate the downstream target of CEBPA-DT. Immunofluorescence, subcellular protein fractionation, western blot, and co-immunoprecipitation were performed to analyze the subcellular location of β-catenin and its interaction with Discoidin domain-containing receptor 2 (DDR2).

RESULTS

CEBPA-DT was upregulated in human HCC tissues with postoperative distant metastasis and intimately related to the worse prognosis of HCC patients. Silencing of CEBPA-DT inhibited the growth, migration and invasion of hepatoma cells in vitro and in vivo, while enhancement of CEBPA-DT played a contrasting role. Mechanistic investigations demonstrated that CEBPA-DT could bind to heterogeneous nuclear ribonucleoprotein C (hnRNPC), which facilitated cytoplasmic translocation of hnRNPC, enhanced the interaction between hnRNPC and DDR2 mRNA, subsequently promoted the expression of DDR2. Meanwhile, CEBPA-DT induced epithelial-mesenchymal transition (EMT) process through upregulation of Snail1 via facilitating nuclear translocation of β-catenin. Using DDR2 inhibitor, we revealed that the CEBPA-DT induced the interaction between DDR2 and β-catenin, thus promoting the nuclear translocation of β-catenin to activate transcription of Snail1, contributing to EMT and HCC metastasis.

CONCLUSIONS

Our results suggested that CEBPA-DT promoted HCC metastasis through DDR2/β-catenin mediated activation of Snail1 via interaction with hnRNPC, indicating that the CEBPA-DT-hnRNPC-DDR2/β-catenin axis may be used as a potential therapeutic target for HCC treatment.

A novel prognostic model based on six methylation-driven genes predicts overall survival for patients with clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a lethal urological malignancy. DNA methylation is involved in the regulation of ccRCC occurrence and progression. This study aimed to establish a prognostic model based on DNA methylation to predict the overall survival (OS) of patients with ccRCC. To create this model, we used the transcriptome and DNA methylation data of patients with ccRCC from The Cancer Genome Atlas (TCGA) database. We then used the MethylMix R package to identify methylation-driven genes, and LASSO regression and multivariate Cox regression analyses established the prognostic risk model, from which we derived risk scores. We incorporated these risk scores and clinical parameters to develop a prognostic nomogram to predict 3-, 5-, and 7-year overall survival, and its predictive power was validated using the ArrayExpress cohort. These analyses identified six methylation-driven genes (SAA1, FUT6, SPATA18, SHROOM3, AJAP1, and NPEPL1) that produced risk scores, which were sorted into high- and low-risk patient groups. These two groups differed in nomogram-predicted prognosis, the extent of immune cell infiltration, tumor mutational burden, and expected response to additional therapies. In conclusion, we established a nomogram based on six DNA methylation-driven genes with excellent accuracy for prognostic prediction in ccRCC patients. This nomogram model might provide novel insights into the epigenetic mechanism and individualized treatment of ccRCC.

Identifying the role of transient receptor potential channels (TRPs) in kidney renal clear cell carcinoma and their potential therapeutic significances using genomic and transcriptome analyses

Kidney renal clear cell carcinoma (KIRC) is among the major causes of cancer-caused mortality around the world. Transient receptor potential channels (TRPs), due to their role in various human diseases, might become potential drug targets in cancer. The mRNA expression, copy number variation, single-nucleotide variation, prognostic values, drug sensitivity, and pathway regulation of TRPs were studied across cancer types. The ArrayExpress and The Cancer Genome Atlas (TCGA) databases were used to retrieve KIRC samples. Simultaneously, training, internal, and external cohorts were grouped. In KIRC, a prognostic signature with superior survival prediction in contrast with other well-established signatures was created after a stepwise screening of optimized genes linked to TRPs using univariate Cox, weighted gene co-expression network analysis, multivariate Cox, and least absolute shrinkage and selection operator regression analyses. Subsequent to the determination of risk levels, the variations in the expression of immune checkpoint genes, tumor mutation burden, and immune subtypes and response between low-risk and high-risk subgroups were studied using a variety of bioinformatics algorithms, including ESTIMATE, XCELL, EPIC, CIBERSORT-ABS, CIBERSORT, MCPCOUNTER, TIMER, and QUANTISEQ. Gene set enrichment analysis helped in the identification of abnormal pathways across the low- and high-risk subgroups. Besides, high-risk KIRC patients might benefit from ABT888, AZD6244, AZD7762, Bosutinib, Camptothecin, CI1040, JNK inhibitor VIII, KU55933, Lenalidomide, Nilotinib, PLX4720, RO3306, Vinblastine, and ZM.447439; however, low-risk populations might benefit from Bicalutamide, FH535, and OSI906. Finally, calibration curves were used to validate the nomogram with a satisfactory predictive survival probability. In conclusion, this research provides useful insight that can aid and guide clinical practice and scientific research.

Expression Patterns of Ezrin and AJAP1 and Clinical Significance in Breast Cancer

Ezrin and adherens junction-associated protein 1 (AJAP1) are structural proteins which are involved in numerous human malignancies. However, little is known about the relationship between them in breast cancer. This study was set out to investigate the relationship between them and to further explore the mechanism of AJAP1-mediating cytoskeleton in breast cancer progression. Ezrin and AJAP1 expressions were detected in 377 samples of breast cancer by immunohistochemistry, and different expression patterns between AJAP1 and Ezrin with clinicopathological parameters were analyzed. Besides, univariate and multivariate Cox models were used to evaluate their prognostic potential. Enzyme-linked immunosorbent assay, Western blot, qRT-PCR, and phalloidin staining of F-actin were used to explore the relationship and the mechanism between AJAP1 and Ezrin in cytoskeleton arrangement. 377 cases of breast cancer results showed that AJAP1 expression was negatively related with histological grade and lymph node involvement and could be an independent prognosis marker of breast cancer. AJAP1 expression tended to be higher in the Ezrin-negative expression case. Patients with AJAP1^negative and Ezrin^positive expression had a worse prognosis (p < 0.0001) and shorter DFS (p = 0.015). More importantly, AJAP1 depletion increased the cell ability of F-actin formation through promoting Ezrin expression. AJAP1 depletion might mediate breast cancer malignancy potential through promoting Ezrin expression and cytoskeleton formation.

Footprints of microRNAs in Cancer Biology

MicroRNAs (miRNAs) are short non-coding RNAs involved in post-transcriptional gene regulation. Over the past years, various studies have demonstrated the role of aberrant miRNA expression in the onset of cancer. The mechanisms by which miRNA exerts its cancer-promoting or inhibitory effects are apparent through the various cancer hallmarks, which include selective proliferative advantage, altered stress response, vascularization, invasion and metastasis, metabolic rewiring, the tumor microenvironment and immune modulation; therefore, this review aims to highlight the association between miRNAs and the various cancer hallmarks by dissecting the mechanisms of miRNA regulation in each hallmark separately. It is hoped that the information presented herein will provide further insights regarding the role of cancer and serve as a guideline to evaluate the potential of microRNAs to be utilized as biomarkers and therapeutic targets on a larger scale in cancer research.

LncRNA FGF14-AS2 represses growth of prostate carcinoma cells via modulating miR-96-5p/AJAP1 axis

OBJECTIVE

This investigation devoted to lncRNA FGF14 antisense RNA 2 (FGF14-AS2) in prostate carcinoma progression.

METHODS

The levels of lncRNA FGF14-AS2, miR-96-5p, and Adherens junction-associated protein-1 (AJAP1) in prostate carcinoma were tested by Western blot and qRT-PCR. How these two genes interacted was confirmed by RNA immunoprecipitation and dualluciferase gene methods. The effect of FGF14-AS2/miR-96-5p/AJAP1 axis in prostate carcinoma progression was determined by MTT, Transwell, and nude mice tumor model.

RESULTS

FGF14-AS2 was a downregulated lncRNA in prostate carcinoma tissue and cells. FGF14-AS2 could restrain miR-96-5p expression while miR-96-5p hampered AJAP1. FGF14-AS2 could effectively decrease the biological behaviors of prostate carcinoma cells, while knock-down of FGF14-AS2 triggered opposite results. Moreover, miR-96-5p mimic presented a cancer promoter role in prostate carcinoma cells. AJAP1 expression level could affect levels of proteins related to epithelial-mesenchymal transition. In vivo experiment suggested that overexpressing FGF14-AS2 could reverse the promotion of silenced AJAP1 on prostate carcinoma cell metastasis, thus to inhibit tumor growth.

CONCLUSION

lncRNA FGF14-AS2 was a downregulated lncRNA in prostate carcinoma and influenced cell proliferation and metastasis. The influence relied on modulating miR-96-5p and its target gene AJAP1.

Cryptotanshinone, a novel PDK 4 inhibitor, suppresses bladder cancer cell invasiveness via the mTOR/β‑catenin/N‑cadherin axis

The phosphorylation of pyruvate dehydrogenase (PDH) by pyruvate dehydrogenase kinase (PDK) 4 inhibits its ability to induce a glycolytic shift. PDK4 expression is upregulated in various types of human cancer. Because PDK4 regulation is critical for metabolic changes in cancer cells, it is an attractive target for cancer therapy given its ability to shift glucose metabolism. It was previously shown that a novel PDK4 inhibitor, cryptotanshinone (CPT), suppressed the three‑dimensional (3D)‑spheroid formation of pancreatic and colorectal cancer cells. In the present study, the effects of CPT on the invasiveness of bladder cancer cells were investigated. CPT significantly suppressed the invasiveness and 3D‑spheroid formation of T24 and J82 bladder cancer cells. CPT also suppressed the phosphorylation of PDH and β‑catenin, as well as the expression of N‑cadherin, which are all critical for inducing epithelial‑mesenchymal transition (EMT). The knockdown of β‑catenin or PDK4 using specific small interfering RNAs suppressed N‑cadherin expression and invasiveness in T24 cells. An mTOR inhibitor also suppressed the phosphorylation of β‑catenin and N‑cadherin expression. Furthermore, CPT injection significantly suppressed pancreatic tumor growth and peritoneal dissemination of highly metastatic SUIT‑2 pancreatic cancer cells in a mouse orthotopic pancreatic cancer model, without evident toxicity. Moreover, immunohistochemistry analyses demonstrated decreased β‑catenin expression in CPT‑treated pancreatic tumors compared with control tumors. Taken together, these results indicate that CPT reduced the invasiveness and metastasis of bladder cancer cells by suppressing EMT via the mTOR/β‑catenin/N‑cadherin pathway.

Targeting Long Non-Coding RNAs in Hepatocellular Carcinoma: Progress and Prospects

Hepatocellular carcinoma is the fifth-ranked cancer worldwide with a relatively low five-year survival rate. Long non-coding RNAs are a group of RNAs with remarkable aberrant expression which could act on multiple bioprocesses and ultimately impact upon tumor proliferation, invasion, migration, metastasis, apoptosis, and therapy resistance in cancer cells including hepatocellular carcinoma cells. In recent years, long non-coding RNAs have been reported to be indispensable targets in clinical target therapy to stop the growth of cancer and prolong the lifespan of patients with hepatocellular carcinoma. In this review, we enumerate the signaling pathways and life activities affected by long non-coding RNAs in hepatocellular carcinoma cells to illustrate the role of long non-coding RNAs in the development and therapy resistance of hepatocellular carcinoma.

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-inducible miR-196a modulates glioblastoma cell proliferation and migration through complex regulation of NRAS

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor in humans. Hypoxia has been correlated with the aggressive form of glial tumors, poor prognosis, recurrence and resistance to various therapies. MicroRNAs (miRNAs) have emerged as critical mediators of hypoxic responses and have shown great potential for cancer diagnostics and therapeutics. Here, we focus on the regulatory and functional characterization of miR-196a, a hypoxia-inducible miRNA, in GBM.

METHODS

Hypoxia/HIF regulation of miR-196a was assessed by RT-qPCR, promoter-luciferase and ChIP assays in GBM cell lines. miR-196a levels were analyzed in The Cancer Genome Atlas (TCGA)-GBM, Chinese Glioma Genome Atlas (CGGA) and Indian GBM patient cohorts. miR-target interactions were studied using RNA/protein quantification and 3'UTR luciferase assays. The effect of miR-196a overexpression/inhibition was assessed on cellular viability, migration and apoptosis under hypoxia and normoxia. Microarray-based gene expression profiling studies were performrd to study the effect of miR-196a on the GBM cellular transcriptome under hypoxia.

RESULTS

We identified miR-196a as a hypoxia-inducible and hypoxia-inducible factor (HIF)-regulated miRNA that plays an oncogenic role in GBM. miR-196a was found to be significantly up-regulated in TCGA-GBM, CGGA glioma as well as Indian GBM patient cohorts. miR-196a overexpression was found to induce cellular proliferation, migration, spheroid formation and colony formation and to inhibit apoptosis, while miR-196a inhibition using anti-miR-196a yielded opposite results, suggesting an oncogenic role of miR-196a in GBM. We further unveiled NRAS, AJAP1, TAOK1 and COL24A1 as direct targets of miR-196a. We also report a complex competitive regulation of oncogenic NRAS by miR-196a, miR-146a and let-7 in GBM. Analysis of microarray-based gene expression data obtained by miR-196a inhibition under hypoxia revealed a role of miR-196a in HIF, calcium adhesion, Wnt and cell adhesion pathways. Interestingly, miR-196a was found to positively regulate the expression of various genes involved in the induction or stabilization of HIFs and in maintenance of hypoxic conditions, thereby suggesting the existence of an indirect miR-196a/HIF positive feedback loop under hypoxia.

CONCLUSIONS

Overall, our work identifies a novel association between hypoxia/HIF signalling and miR-196a in GBM and suggests its therapeutic significance.

NCSTN promotes hepatocellular carcinoma cell growth and metastasis via β-catenin activation in a Notch1/AKT dependent manner

BACKGROUND

Hepatocellular carcinoma is the third top cause of cancer-related mortalities worldwide. The prognosis of HCC patients remains poor due to rapid progression and high incidence of tumor recurrence. Nicastrin (NCSTN), a core subunit of γ-Secretase, has been reported to play a vital role in tumor progression. However, no study till now has revealed its role in HCC.

METHODS

The expression of NCSTN was evaluated by immunohistochemical staining, Western blot, and quantitative real-time PCR. Cell counting kit-8, colony formation and cell cycle assays were used for evaluating cell growth in vitro. Transwell and wound-healing assays were used for evaluating cell migration and invasion capacity. Immunofluorescence, subcellular protein fractionation and co-immunoprecipitation were used for location analysis of β-catenin. The in vivo functions of NCSTN were illustrated by xenograft tumor models.

RESULTS

NCSTN was dramatically overexpressed in HCC compared to normal liver tissues. Elevated NCSTN expression level was significantly correlated to worse overall and recurrence-free survival of HCC patients. Enhanced NCSTN expression promoted HCC cell growth, migration and invasion in vitro and in vivo. Mechanistic investigations showed that NCSTN induced epithelial-mesenchymal transition (EMT) process via upregulation of Zeb1. Subsequently, we revealed that NCSTN facilitated nuclear translocation of β-catenin, a positive transcriptional regulator of Zeb1. Using Notch and AKT inhibitors, we revealed that NCSTN promoted β-catenin activation through Notch1 and AKT signaling pathway. NCSTN increased AKT and GSK-3β phosphorylation by cleavage of Notch1, which decreased GSK-3β/β-catenin complex. The inactivation of GSK-3β inhibited the β-catenin degradation and promoted nuclear translocation of β-catenin to initiate transcription of Zeb1, resulting in malignant phenotype.

CONCLUSIONS

Our results demonstrated that NCSTN promoted HCC cell growth and metastasis via β-catenin-mediated upregulation of Zeb1 in a Notch1/AKT dependent manner, suggesting that NCSTN might serve as a potential prognostic marker and therapeutic target for HCC.

Downregulation of TET1 Promotes Bladder Cancer Cell Proliferation and Invasion by Reducing DNA Hydroxymethylation of AJAP1

Ten-eleven translocation 1 (TET1) is a member of methylcytosine dioxygenase, which catalyzes 5-methylcytosine (5 mC) to 5-hydroxymethylcytosine (5 hmC) to promote the demethylation process. The dysregulated TET1 protein and 5 hmC level were reported to either suppress or promote carcinogenesis in a cancer type-dependent manner. Currently, the role of TET1 in the development of urinary bladder cancer (UBC) and its underlying molecular mechanisms remain unclear. Herein, we found that TET1 expression was downregulated in UBC specimens compared with normal urothelium and was inversely related to tumor stage and grade and overall survival, suggesting its negative association with UBC progression. TET1 silencing in UBC cells increased cell proliferation and invasiveness while the ectopic expression of wild-type TET1-CD, but not its enzymatic inactive mutant, reversed these effects and suppressed tumorigenicity in vivo. In addition, as a direct regulator of TET1 activity, vitamin C treatment increased 5 hmC level and inhibited the anchorage-independent growth and tumorigenicity of UBC cells. Furthermore, we found that TET1 maintained the hypomethylation in the promoter of the AJAP1 gene, which codes for adherens junction-associated protein 1. The downregulation of AJAP1 reversed TET1-CD-induced nuclear translocation of β-catenin, thus inhibiting the expression of its downstream genes. In human UBC specimens, AJAP1 is frequently downregulated and positively associated with TET1. Notably, low expression levels of both TET1 and AJAP1 predict poor prognosis in UBC patients. In conclusion, we found that the frequently downregulated TET1 level reduces the hydroxymethylation of AJAP1 promoter and subsequently activates β-catenin signaling to promote UBC development. The downregulation of both TET1 and AJAP1 might be a promising prognostic biomarker for UBC patients.

Investigation of the Correlation between Androgen Receptor and ZEB1 and its Value in Progression of Gastric Cancer

BACKGROUND

Zinc-finger Enhancer Binding protein (ZEB1) acts as a transcription factor to promote cancer progression through regulating Epithelial to Mesenchymal Transition (EMT). It is well-known that ZEB1 mRNA expression is directly induced by both Estrogen Receptor (ER) and Progesterone Receptor (PR). Moreover, Androgen Receptor (AR) and PR could bind to the same regulatory element. Since it has been shown that AR overexpresses in Gastric Cancer (GC) as a male-predominant tumor, the goal of this study was to evaluate whether AR could regulate ZEB1 expression in GC.

METHODS

The expression profile of ZEB1 in 60 fresh GC and adjacent non-tumor tissues and 50 normal gastric specimens was assessed by qRT-PCR, and the association of ZEB1 expression with clinicopathological features was investigated. Furthermore, possible correlation between ZEB1 and AR was evaluated to elucidate a novel prognostic marker using Kaplan-Meier method and Cox regression model. Finally, molecular interaction of ZEB1 and AR was assessed using a potent AR antagonist in GC cells.

RESULTS

Among GC patients, 70.2% (40/57) overexpressed ZEB1 and 64.91% (37/57) overexpressed AR relative to normal gastric tissues. ZEB1 overexpression was significantly correlated with the AR overexpression in GC patients. Moreover, ZEB1 overexpression was remarkably associated with lower overall survival; however, it was not an independent prognostic factor. Evidence shows that simultaneous evaluation of ZEB1 and AR expression could independently predict survival of GC patients (HR= 2.193, p=0.047).

CONCLUSION

These findings have clinical importance suggesting simultaneous evaluation of ZEB1 and AR expression as a potential prognostic marker. Moreover, AR may regulate ZEB1 expression in GC cells proposing a possible promising targeted therapy for GC patients.

Advances in delivery vectors for gene therapy in liver cancer

Hepatocellular carcinoma (HCC) is the third most common cause of cancer death globally, mainly due to lack of effective treatments – a problem that gene therapy is poised to solve. Successful gene therapy requires safe and efficient delivery vectors, and recent advances in both viral and nonviral vectors have made an important impact on HCC gene therapy delivery. This review explores how adenoviral, retroviral and adeno-associated viral vectors have been modified to increase safety and delivery capacity, highlighting studies and clinical trials using these vectors for HCC gene therapy. Nanoparticles, liposomes, exosomes and virosomes are also featured in their roles as HCC gene delivery vectors. Finally, new discoveries in gene editing technology and their impacts on HCC gene therapy are discussed.

β-Catenin nuclear localization positively feeds back on EGF/EGFR-attenuated AJAP1 expression in breast cancer

BACKGROUND

Adherent junction associated protein 1 (AJAP1), a typical molecule of adherent junctions, has been found to be a tumor suppressor in many cancer types. Aberrant activation of β-catenin has been demonstrated to be associated with malignant biological properties of tumors including breast cancer. This study aimed to investigate the function and mechanism of AJAP1-mediated β-catenin activity of breast cancer lines in vitro and in breast cancer patients.

METHODS

AJAP1 and β-catenin expressions in breast cancer tissues and cell lines were detected by immunohistochemistry, western blotting and qRT-PCR. The EGF/EGFR axis-mediated AJAP1 attenuated β-catenin nuclear location was measured by western blotting, immunofluorescence assay, co-immunoprecipitation, luciferase assay and ubiquitination assays. Furthermore, the function of AJAP1 and β-catenin regulated breast cancer progression was explored both in vivo and in vitro.

RESULTS

It was found that AJAP1 had a high negative correlation with β-catenin nuclear expression and was a novel tumor suppressor in breast cancer. AJAP1 loss can mediate β-catenin accumulated in cytoplasm and then transferred it to the nucleus, activating β-catenin transcriptional activity and downstream genes. Additionally, β-catenin can reverse the invasion, proliferation ability and tumorigenicity of the depletion of AJAP1 caused both in vivo and in vitro. Besides, EGF/EGFR also involved in the process of AJAP1-depiction induced β-catenin transactivation to the nucleus. More importantly, EGFR depletion/AJAP1 knocked down promoted the progression of breast cancer by regulating the activity of β-catenin nuclear transactivation.

CONCLUSION

This study demonstrated that AJAP1 acted as a putative tumor suppressor while β-catenin nuclear localization positively fed back on EGF/EGFR-attenuated AJAP1 expression in breast cancer, which might be beneficial to develop new therapeutic targets for decreasing nuclear β-catenin-mediated malignancy in breast cancer.

Upregulation of cystatin SN promotes hepatocellular carcinoma progression and predicts a poor prognosis

Cystatin SN, a specific cysteine protease inhibitor, is thought to be involved in various malignant tumors. Therefore, we evaluated the role of cystatin SN in hepatocellular carcinoma (HCC). Notably, cystatin SN was elevated in tumorous samples and cells. Moreover, overexpression of cystatin SN was correlated with tumor diameter and TNM stage. Cox multivariate analysis displayed that cystatin SN was an independent prognosis indicator and that high cystatin SN level was associated with a dismal prognosis. Moreover, cystatin SN enhancement facilitated the proliferation, migratory, and invasive potential of Huh7 and HCCLM3 cells, whereas cystatin SN knockdown caused the opposite effect. Cystatin SN also modulated the epithelial‐mesenchymal transition progression through the PI3K/AKT pathway. In vivo cystatin SN promoted HCCLM3 cell growth and metastasis in xenograft mice model. Thus, cystatin SN was involved in HCC progression and could be a latent target for HCC treatment.

Untangling the response of bone tumor cells and bone forming cells to matrix stiffness and adhesion ligand density by means of hydrogels

How cancer cells and their anchorage-dependent normal counterparts respond to the adhesion ligand density and stiffness of the same extracellular matrix (ECM) is still not very clear. Here we investigated the effects of ECM adhesion ligand density and stiffness on bone tumor cells (osteosarcoma cells) and bone forming cells (osteoblasts) by using poly (ethylene glycol) diacrylate (PEGDA) and methacrylated gelatin (GelMA) hydrogels. By independently changing the PEGDA and GelMA content in the hydrogels, we achieved crosslinked hydrogel matrix with independently tunable stiffness (1.6, 6 and 25 kPa for 5%, 10%, 15% PEDGA, respectively) and adhesion ligand density (low, medium and high for 0.05%, 0.2%, 0.5% GelMA respectively). By using a series of biochemical and cell biological characterizations as well as in vivo studies, we confirmed that osteosarcoma and osteoblastic cells responded differently to the stiffness and adhesion ligand density within 3D ECM. When cultured within the 3D PEGDA/GelMA hydrogel matrix, osteosarcoma cells are highly dependent on the matrix stiffness via regulating the integrin-mediated focal adhesion (FA) pathway, whereas osteoblasts are highly sensitive to the matrix adhesion ligand density through regulating the integrin-mediated adherens junction (AJ) pathway. However, when seeded on the 2D surface of the hydrogels, osteosarcoma cells behaved differently and became sensitive to the matrix adhesion ligand density because they were "forced" to attach to the substrate, similar to anchorage-dependent osteoblasts. This study might provide new insights into rational design of scaffolds for generating in vitro tumor models to test anticancer therapeutics and for regenerating tissue to repair defects.

KIFC1 regulated by miR-532-3p promotes epithelial-to-mesenchymal transition and metastasis of hepatocellular carcinoma via gankyrin/AKT signaling

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide. The poor survival may be due to a high proportions of tumor recurrence and metastasis. Kinesin family member C1 (KIFC1) is highly expressed in a variety of neoplasms and is a potential marker for non-small cell lung cancer or ovarian adenocarcinoma metastasis. Nevertheless, the role of KIFC1 in HCC metastasis remains obscure. We investigated this in the present study using HCC cell lines and clinical specimens. Our results indicated that increased levels of KIFC1 were associated with poor prognosis and metastasis in HCC. In addition, KIFC1 induced epithelial-to-mesenchymal transition (EMT) and HCC metastasis both in vitro and in vivo. This tumorigenic effect depended on gankyrin; inhibiting gankyrin activity reversed EMT via activation of protein kinase B (AKT)/Twist family BHLH transcription factor 1 (AKT/TWIST1). We also found that KIFC1 was directly regulated by the microRNA miR-532-3p, whose downregulation was associated with metastatic progression in HCC. These results denote that a decrease in miR-532-3p levels results in increased KIFC1 expression in HCC, leading to metastasis via activation of the gankyrin/AKT/TWIST1 signaling pathway.

Long Non-Coding RNA MALAT1 Regulates ZEB1 Expression by Sponging miR-143-3p and Promotes Hepatocellular Carcinoma Progression

Hepatocellular carcinoma (HCC) is one of the most common malignancies. Long non-coding RNAs (lncRNAs) are involved in HCC. This study aimed to explore the effects of lncRNA MALAT1 on HCC development. MALAT1, ZEB1, and miR-143-3p in HCC tissues was detected by qRT-PCR. Effect of MALAT1 on the proliferation and metastasis of HCC cells was estimated by cell-counting, wound-healing, and transwell assays. Luciferase reporter assays were used to explore miR-143-3p's target, ZEB1. QRT-PCR and Western blot were employed to determine the effects of MALAT1 or/and miR-143-3p on ZEB1 expression. MALAT1 was upregulated in HCC tissues. ZEB1 was a target of miR-143-3p. miR-143-3p binds with MALAT1, and was regulated by MALAT1. The regulation of MALAT1 on ZEB1 was mediated by miR-143-3p. Transfection with siR-MALAT1 significantly inhibited cell proliferation and invasion, while knockdown of miR-181a partially reversed these effects. Our findings suggest that MALAT1 may regulate ZEB1 expression by sponging miR-143-3p and promotes hepatocellular carcinoma progression. J. Cell. Biochem. 118: 4836-4843, 2017. © 2017 Wiley Periodicals, Inc.