Mapping the STK4/Hippo signaling network in prostate cancer cell

Hippo signaling modulation and its biological implications in urological malignancies

Although cancer diagnosis and treatment have rapidly advanced in recent decades, urological malignancies, which have high morbidity and mortality rates, are among the most difficult diseases to treat. The Hippo signaling is an evolutionarily conserved pathway in organ size control and tissue homeostasis maintenance. Its downstream effectors, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), are key modulators of numerous physiological and pathological processes. Recent work clearly indicates that Hippo signaling is frequently altered in human urological malignancies. In this review, we discuss the disparate viewpoints on the upstream regulators of YAP/TAZ and their downstream targets and systematically summarize the biological implications. More importantly, we highlight the molecular mechanisms involved in Hippo-YAP signaling to improve our understanding of its role in every stage of prostate cancer, bladder cancer and kidney cancer progression. A better understanding of the biological outcomes of YAP/TAZ modulation will contribute to the establishment of future therapeutic approaches.

Comprehensive DNA methylation profiling by MeDIP-NGS identifies potential genes and pathways for epithelial ovarian cancer

Ovarian cancer, among all gynecologic malignancies, exhibits the highest incidence and mortality rate, primarily because it is often presents with non-specific or no symptoms during its early stages. For the advancement of Ovarian Cancer Diagnosis, it is crucial to identify the potential molecular signatures that could significantly differentiate between healthy and ovarian cancerous tissues and can be used further as a diagnostic biomarker for detecting ovarian cancer. In this study, we investigated the genome-wide methylation patterns in ovarian cancer patients using Methylated DNA Immunoprecipitation (MeDIP-Seq) followed by NGS. Identified differentially methylated regions (DMRs) were further validated by targeted bisulfite sequencing for CpG site-specific methylation profiles. Furthermore, expression validation of six genes by Quantitative Reverse Transcriptase-PCR was also performed. Out of total 120 differentially methylated genes (DMGs), 68 genes were hypermethylated, and 52 were hypomethylated in their promoter region. After analysis, we identified the top 6 hub genes, namely POLR3B, PLXND1, GIGYF2, STK4, BMP2 and CRKL. Interestingly we observed Non-CpG site methylation in the case of POLR3B and CRKL which was statistically significant in discriminating ovarian cancer samples from normal controls. The most significant pathways identified were focal adhesion, the MAPK signaling pathway, and the Ras signaling pathway. Expression analysis of hypermethylated genes was correlated with the downregulation of the genes. POLR3B and GIGYF2 turned out to be the novel genes associated with the carcinogenesis of EOC. Our study demonstrated that methylation profiling through MeDIP-sequencing has effectively identified six potential hub genes and pathways that might exacerbate our understanding of underlying molecular mechanisms of ovarian carcinogenesis.

VEPH1 suppresses the progression of gastric cancer by regulating the Hippo-YAP signalling pathway

BACKGROUND

Ventricular zone-expressed PH domain-containing protein homologue 1 (VEPH1) is a recently discovered intracellular adaptor protein that plays an important role in human development. It has been reported that VEPH1 is closely related to the process of cellular malignancy, but its role in gastric cancer has not been elucidated. This study investigated the expression and function of VEPH1 in human gastric cancer (GC).

METHODS

We performed qRT‒PCR, Western blotting, and immunostaining assays in GC tissue samples to evaluate VEPH1 expression. Functional experiments were used to measure the malignancy of GC cells. A subcutaneous tumorigenesis model and peritoneal graft tumour model were established in BALB/c mice to determine tumour growth and metastasis in vivo.

RESULTS

VEPH1 expression is decreased in GC and correlates with the overall survival rates of GC patients. VEPH1 inhibits GC cell proliferation, migration, and invasion in vitro and suppresses tumour growth and metastasis in vivo. VEPH1 regulates the function of GC cells by inhibiting the Hippo-YAP signalling pathway, and YAP/TAZ inhibitor-1 treatment reverses the VEPH1 knockdown-mediated increase in the proliferation, migration and invasion of GC cells in vitro. Loss of VEPH1 is associated with increased YAP activity and accelerated epithelial-mesenchymal transition (EMT) in GC.

CONCLUSION

VEPH1 inhibited GC cell proliferation, migration, and invasion in vitro and in vivo and exerted its antitumour effects by inhibiting the Hippo-YAP signalling pathway and EMT process in GC.

Comprehensive analysis of alternative splicing across multiple transcriptomic cohorts reveals prognostic signatures in prostate cancer

BACKGROUND

Alternative splicing (AS) plays a crucial role in transcriptomic diversity and is a hallmark of cancer that profoundly influences the development and progression of prostate cancer (PCa), a prevalent and potentially life-limiting cancer among men. Accumulating evidence has highlighted the association between AS dysregulation and the onset and progression of PCa. However, a comprehensive and integrative analysis of AS profiles at the event level, utilising data from multiple high-throughput cohorts and evaluating the prognosis of PCa progression, remains lacking and calls for thorough exploration.

RESULTS

We identified a differentially expressed retained intron event in ZWINT across three distinct cohorts, encompassing an original array-based dataset profiled by us previously and two RNA sequencing (RNA-seq) datasets. Subsequent in-depth analyses of these RNA-seq datasets revealed  141 altered events, of which 21 demonstrated a significant association with patients' biochemical recurrence-free survival (BCRFS). We formulated an AS event-based prognostic signature, capturing six pivotal events in genes CYP4F12, NFATC4, PIGO, CYP3A5, ALS2CL, and FXYD3. This signature effectively differentiated  high-risk patients diagnosed with PCa, who experienced shorter BCRFS, from their low-risk counterparts. Notably, the signature's predictive power surpassed traditional clinicopathological markers in forecasting 5-year BCRFS, demonstrating robust performance in both internal and external validation sets. Lastly, we constructed a novel nomogram that integrates patients' Gleason scores with pathological tumour stages, demonstrating improved prognostication of BCRFS.

CONCLUSIONS

Prediction of clinical progression remains elusive in PCa. This research uncovers novel splicing events associated with BCRFS, augmenting existing prognostic tools, thus potentially refining clinical decision-making.

The role of DNA methylation in ovarian cancer chemoresistance: A narrative review

Background and Aims

Ovarian cancer (OC) is the most lethal gynecological cancer. In 2018, it was responsible for over 180,000 deaths worldwide. The high mortality rate is the culmination of a lack of early diagnosis and high rates of chemotherapy resistance, which is synonymous with disease recurrence. Over the last two decades, an increasingly significant role of epigenetic mechanisms, in particular DNA methylation, has emerged. This review will discuss several of the most significant genes whose hypo/hypermethylation profiles are associated with chemoresistance. Aside from functionally elucidating and evaluating these epimutations, this review will discuss recent trials of DNA methyltransferase inhibitors (DNMTi). Finally, we will propose future directions that could enhance the feasibility of utilizing these candidate epimutations as clinical biomarkers.

Methods

To perform this review, a comprehensive literature search based on our keywords was conducted across the online databases PubMed and Google Scholar for identifying relevant studies published up until August 2022.

Results

Epimutations affecting MLH1, MSH2, and Ras-association domain family 1 isoform A (DNA damage repair and apoptosis); ATP-binding cassette subfamily B member 1 and methylation-controlled J (drug export); secreted frizzled-related proteins (Wnt/β-catenin signaling), neurocalcin delta (calcium and G protein-coupled receptor signaling), and zinc finger protein 671 all have potential as biomarkers for chemoresistance. However, specific uncertainties relating to these epimutations include histotype-specific differences, intrinsic versus acquired chemoresistance, and the interplay with complete surgical debulking. DNMTi for chemoresistant OC patients has shown some promise; however, issues surrounding their efficacy and dose-limiting toxicities remain; a personalized approach is required to maximize their effectiveness.

Conclusion

Establishing a panel of aberrantly methylated chemoresistance-related genes to predict chemoresponsiveness and patients' suitability to DNMTi could significantly reduce OC recurrence, while improving DNMTi therapy viability. To achieve this, a large-scale prospective genome-wide DNA methylation profile study that spans different histotypes, includes paired samples (before and after chemotherapy), and integrates transcriptomic and methylomic analysis, is warranted.

LncRNA STK4 antisense RNA 1 (STK4-AS1) promoted osteosarcoma by inhibiting p53 expression

BACKGROUND

LncRNA STK4 antisense RNA 1 (STK4-AS1) has been identified as a potential biomarker associated with multiple cancers. We proposed that STK4-AS1 plays a role in the proliferation of osteosarcoma by regulating the cell cycle.

METHODS

We compared the expression of STK4-AS1, p53, and p21 in osteosarcoma vs normal samples in clinical tissues and cell lines. We determined the effect of overexpression and knockdown of STK4-AS1 in p53 expressing osteosarcoma cells U2OS, p53 muted osteosarcoma cells MG63, and osteoblast cells hFOB on p53 and p21 expression and the cell viability. For U2OS and MG63, the cell cycle was analyzed and the expression of cyclin proteins was determined. We overexpressed p53 or p21 in STK4-AS1 overexpressed cells to explore the association of STK4-AS1 and p53 in U2OS.

RESULTS

The STK4-AS1 expression was higher and p53 and p21 expression were lower in osteosarcoma tissue and cells than in their non-cancer counterparts. The expression of STK4-AS1 was negatively correlated with the expression of p53 or p21. Knockdown of STK4-AS1 in U2OS decreased the cell viability, increased cells in the G0/G1 phase, decreased cells in the S and G2/M phase, decreased expression of cyclin A and B, increased p53 and p21, and had no effect on cyclin D and cyclin E, while overexpression of STK4-AS1 did the opposes. Overexpression of p53 or p21 recovered some changes caused by STK4-AS1 overexpression in U2OS. MG63 expressed no p53 and the expression of p21, cyclin A, and cyclin B, cell viability, and cell cycle were not affected by altered STK4-AS1 levels. In hFOB cells, the expression of p53 and p21 was decreased and the cell viability was increased when STK4-AS1 was overexpressed, but they were not affected when STK4-AS1 was knocked down.

CONCLUSION

LncRNA STK4-AS1 promoted the cell cycle of osteosarcoma cells by inhibiting p53 expression.

Salvianolic acid B exerts an anti-hepatocellular carcinoma effect by regulating the Hippo/YAP pathway and promoting pSmad3L to pSmad3C simultaneously

Salvianolic acid B (Sal B) is a component obtained from Salvia miltiorrhiza and is empirically used for liver diseases. The TGF-β/Smad and Hippo/YAP pathways may interact with each other in hepatocellular carcinoma (HCC). Previously, we found that Sal B mediates the TGF-β/Smad pathway in mice and delays liver fibrosis-carcinoma progression by promoting the conversion of pSmad3L to pSmad3C, but the effect of Sal B on the Hippo/YAP pathway has not been determined. Therefore, we used a DEN/CCl₄/C₂H₅OH-induced liver cancer model in mice to analyze liver index and tumor incidence, detect AST and ALT serological markers, observe liver pathology and the number of Ki67-positive cells to evaluate the anti-HCC effect of Sal B in vivo. We used a TGF-β₁-induced HepG2 cell model, and applied an MST1/2 inhibitor, XMU-MP-1, to detect the changes in pSmad3C/pSmad3L signaling induced by MST1/2 inhibition. Sal B significantly inhibited tumorigenesis in DEN/CCl₄/C₂H₅OH-induced mice in vivo, and suppressed the growth of HepG2 cells by inhibiting cell proliferation and migration in vitro. Here, our study also validated the role of Sal B in reversing XMU-MP-1-induced proliferation and migration of HepG2 cells in vitro. Most importantly, we elucidated for the first time the potential mechanism of Sal B against HCC via the Hippo/YAP pathway, which may be specifically related to upregulation of MST1 and inhibition of its downstream effector protein YAP. In conclusion, these findings indicate that Sal B possesses anti- HCC effects both in vivo and in vitro by regulating the Hippo/YAP pathway and promoting pSmad3L to pSmad3C synchronously.

Transcriptomic analysis of the liver in aged laying hens with different eggshell strength

Eggshell is composed of a very ordered and mineralized structure and is important for egg quality. Eggshell strength is particularly important because of its direct association with economic outcomes and egg safety. Various factors related to laying hens and their environment affects eggshell strength. However, the molecular mechanisms of liver functions related to decreased eggshell strength of aged laying hens are largely unknown. Therefore, this study aimed to identify potential factors affecting eggshell strength in aged laying hens at the hepatic transcriptomic level. A total of five hundred 92-wk-old Hy-line Brown laying hens were screened to select those exhibiting the greatest variation in eggshell strength. Based on the final eggshell strength, 12 hens producing eggs with strong eggshell strength (SES) and weak eggshell strength (WES) were finally selected (n = 6) for liver tissue sampling. The RNA-sequencing was performed to identify differentially expressed genes (DEGs) between the 2 groups. We identified a total of 2,084 DEGs, of which 1,358 genes were upregulated and 726 genes were downregulated in the WES group compared with SES group. According to the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, the DEGs indicated the mammalian target of rapamycin signaling pathway, the Janus kinase-signal transducer and activator of transcription pathway, the mitogen‑activated protein kinase signaling pathway, and the insulin resistance pathways. Genes related to fatty liver disease were upregulated in WES group compared with SES group. In addition, expression of several genes associated with oxidative stress and bone resorption activity was altered in aged laying hens with different eggshell strength. Overall, these findings contribute to the identification of genes involved in different intensity of eggshell strength, enabling more understanding of the hepatic molecular mechanism underlying in decreased eggshell strength of aged laying hens.

High MST2 expression regulates lens epithelial cell apoptosis in age-related cataracts through YAP1 targeting GLUT1

Age-related cataract (ARC) is a severe visual impairment disease and its pathogenesis remains unclear. This study investigated the relevance of MST2/YAP1/GLUT1 in ARC development in vivo and in vitro, and explored the role and possible mechanisms of this pathway in oxidative damage-mediated apoptosis of lens epithelial cells (LECs). Western blot analysis and immunohistochemistry showed that MST2 and phosphorylated (p)-YAP (Ser127) protein levels were increased, and YAP1 and GLUT1 protein levels were decreased in LECs of ARC patients and aged mice. Additionally, differential expression of MST2 and YAP1 was associated with H₂O₂-induced apoptosis of human lens epithelial B3 (HLE-B3) cells. CCK-8 and Hoechst 33,342 apoptosis assays showed that MST2 and YAP1 were involved in H₂O₂-induced apoptosis of LECs. Subsequent experiments showed that, during MST2-mediated H₂O₂-induced apoptosis, p-YAP (Ser127) levels were elevated and immunofluorescence revealed nucleoplasmic translocation and inhibition of YAP1 protein expression. Furthermore, GLUT1 was in turn synergistically transcriptionally regulated by YAP1-TEAD1 in dual luciferase reporter assays. In conclusion, our study indicates that the MST2/YAP1/GLUT1 pathway plays a major role in the pathogenesis of ARC and LECs apoptosis, providing a new direction for future development of targeted inhibitors that block this signaling pathway to prevent, delay, or even cure ARC.

The Hippo effector YAP1/TEAD1 regulates EPHA3 expression to control cell contact and motility

The EPHA3 protein tyrosine kinase, a member of the ephrin receptor family, regulates cell fate, cell motility, and cell-cell interaction. These cellular events are critical for tissue development, immunological responses, and the processes of tumorigenesis. Earlier studies revealed that signaling via the STK4-encoded MST1 serine-threonine protein kinase, a core component of the Hippo pathway, attenuated EPHA3 expression. Here, we investigated the mechanism by which MST1 regulates EPHA3. Our findings have revealed that the transcriptional regulators YAP1 and TEAD1 are crucial activators of EPHA3 transcription. Silencing YAP1 and TEAD1 suppressed the EPHA3 protein and mRNA levels. In addition, we identified putative TEAD enhancers in the distal EPHA3 promoter, where YAP1 and TEAD1 bind and promote EPHA3 expression. Furthermore, EPHA3 knockout by CRISPR/Cas9 technology reduced cell-cell interaction and cell motility. These findings demonstrate that EPHA3 is transcriptionally regulated by YAP1/TEAD1 of the Hippo pathway, suggesting that it is sensitive to cell contact-dependent interactions.

MicroRNA miR-23b-3p promotes osteosarcoma by targeting ventricular zone expressed PH domain-containing 1 (VEPH1)/phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway

Increasing evidence suggests that dysregulated miRNA expression can lead to the tumorigenesis of osteosarcoma (OS). Nevertheless, the potential role of miR-23b-3p in OS is unclear and remains to be explored. Microarray analysis was performed to identify key genes involved in OS. Reverse transcription quantitative polymerase chain reaction and Western blotting were used to examine miR-23b-3p expression, ventricular zone expressed PH domain-containing 1 (VEPH1) transcript (as well as other transcripts as indicated), and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway-related protein expression. A luciferase reporter gene assay was performed to confirm the regulatory relationship between VEPH1 mRNA and miR-23b-3p. Cell viability was evaluated using the Cell Counting Kit-8 assay, cell growth was assessed using the bromodeoxyuridine enzyme-linked immunosorbent assay, and cell migration was tested using a wound healing assay. We found significant upregulation of miR-23b-3p in OS, which prominently promoted the viability, proliferation, and migration of OS cells. Additionally, VEPH1 was found to be a target of miR-23b-3p and its expression was decreased in OS. Lastly, VEPH1 alleviated the promotion effect of miR-23b-3p on the malignancy phenotypes of OS cells via the PI3K/AKT signaling pathway. Thus, miR-23b-3p augmented the viability, proliferation, and migration of OS cells by directly targeting and downregulating VEPH1, which inhibited the activation of the PI3K/AKT signaling pathway.

The Hippo pathway: an emerging role in urologic cancers

The Hippo pathway controls several biological processes, including cell growth, differentiation, motility, stemness, cell contact, immune cell maturation, organ size, and tumorigenesis. The Hippo pathway core kinases MST1/2 and LATS1/2 in mammals phosphorylate and inactivate YAP1 signaling. Increasing evidence indicates that loss of MST1/2 and LATS1/2 function is linked to the biology of many cancer types with poorer outcomes, likely due to the activation of oncogenic YAP1/TEAD signaling. Therefore, there is a renewed interest in blocking the YAP1/TEAD functions to prevent cancer growth. This review introduces the Hippo pathway components and examines their role and therapeutic potentials in prostate, kidney, and bladder cancer.

The Beneficial Role of Exercise on Treating Alzheimer's Disease by Inhibiting β-Amyloid Peptide

Alzheimer's disease (AD) is associated with a very large burden on global healthcare systems. Thus, it is imperative to find effective treatments of the disease. One feature of AD is the accumulation of neurotoxic β-amyloid peptide (Aβ). Aβ induces multiple pathological processes that are deleterious to nerve cells. Despite the development of medications that target the reduction of Aβ to treat AD, none has proven to be effective to date. Non-pharmacological interventions, such as physical exercise, are also being studied. The benefits of exercise on AD are widely recognized. Experimental and clinical studies have been performed to verify the role that exercise plays in reducing Aβ deposition to alleviate AD. This paper reviewed the various mechanisms involved in the exercise-induced reduction of Aβ, including the regulation of amyloid precursor protein cleaved proteases, the glymphatic system, brain-blood transport proteins, degrading enzymes and autophagy, which is beneficial to promote exercise therapy as a means of prevention and treatment of AD and indicates that exercise may provide new therapeutic targets for the treatment of AD.

Targeting the Hippo Pathway in Prostate Cancer: What's New?

Simple Summary

Prostate cancer is the most commonly diagnosed cancer in men in the UK, accounting for the deaths of over 11,000 men per year. A major problem in this disease are tumours which no longer respond to available treatments. Understanding how this occurs will reveal new ways to treat these patients. In this review, the latest findings regarding a particular group of cellular factors which make up a signalling network called the Hippo pathway will be described. Accumulating evidence suggests that this network contributes to prostate cancer progression and resistance to current treatments. Identifying how this pathway can be targeted with drugs is a promising area of research to improve the treatment of prostate cancer.

Abstract

Identifying novel therapeutic targets for the treatment of prostate cancer (PC) remains a key area of research. With the emergence of resistance to androgen receptor (AR)-targeting therapies, other signalling pathways which crosstalk with AR signalling are important. Over recent years, evidence has accumulated for targeting the Hippo signalling pathway. Discovered in Drosophila melanogasta, the Hippo pathway plays a role in the regulation of organ size, proliferation, migration and invasion. In response to a variety of stimuli, including cell–cell contact, nutrients and stress, a kinase cascade is activated, which includes STK4/3 and LATS1/2 to inhibit the effector proteins YAP and its paralogue TAZ. Transcription by their partner transcription factors is inhibited by modulation of YAP/TAZ cellular localisation and protein turnover. Trnascriptional enhanced associate domain (TEAD) transcription factors are their classical transcriptional partner but other transcription factors, including the AR, have been shown to be modulated by YAP/TAZ. In PC, this pathway can be dysregulated by a number of mechanisms, making it attractive for therapeutic intervention. This review looks at each component of the pathway with a focus on findings from the last year and discusses what knowledge can be applied to the field of PC.

A case report of sinusoidal diffuse large B-cell lymphoma in a STK4 deficient patient

INTRODUCTION

Primary immunodeficiency diseases (PIDs), a rare group of gene defects with different manifestations, are at great risk of malignancy. The incidence of diffuse large B-cell lymphoma in the sinusoidal tract is quite rare with nasal congestion, stuffiness, and pain in maxillary sinus manifestation. Human serine-threonine kinase 4 (STK4) deficiency affects the immune system with recurrent bacterial and viral infections, mucocutaneous candidiasis, cutaneous warts, skin abscesses, T- and B-cell lymphopenia, and neutropenia.

PATIENT CONCERN

In this study we describe the infrequent incidence and successful treatment of sinusoidal diffuse large B-cell lymphoma in a STK4 deficient patient with clinical manifestation of severe intractable headaches, unilateral swelling of her face, nasal congestion, stuffiness, and pain in maxillary.

DIAGNOSIS

Clinical data including headaches, unilateral swelling of face, nasal congestion, stuffiness and pain in maxillary sinus with confirmed histopathology and magnetic resonance imaging finding confirmed sinusoidal diffuse large B cell lymphoma in a STK4 deficient patient.

INTERVENTION

Six cycles of R-CHOP (rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisolone) were administered and after each cycle, G-CSF support was used. Chemotherapeutic drugs were administered with standard dose and no dose reduction was done during the treatment. IVIG treatment continued during the courses of chemotherapy.

OUTCOME

The index patient achieved complete response at the end of chemotherapy courses and was in remission for about 8 months afterward, prior to the date of the present report.

CONCLUSION

PID patient are often at increased risk of malignancies. Sinusoidal diffuse large B-cell lymphoma is quite rare and prognosis is variable. Early attention to patient's manifestation, suitable treatment, and monitoring manifestations caused by PID are critical.

Long non-coding RNA TNRC6C-AS1 promotes methylation of STK4 to inhibit thyroid carcinoma cell apoptosis and autophagy via Hippo signalling pathway

The role of long non-coding RNAs (lncRNAs) in thyroid carcinoma (TC), the most frequent endocrine malignancy, has been extensively examined. This study investigated effect of interaction among lncRNA TNRC6C-AS1, serine/threonine-protein kinase 4 (STK4) and Hippo signalling pathway on TC. Initially, lncRNA TNRC6C-AS1 expression in TC tissues was detected. To explore roles of lncRNA TNRC6C-AS1, STK4 and Hippo signalling pathway in TC progression, their expressions were altered. Interaction between lncRNA TNRC6C-AS1 and STK4, STK4 promoter methylation, or Hippo signalling pathway was verified. After that, a series of experiments were employed to evaluate in vitro ability of apoptosis, proliferation and autophagy of TC cells and in vivo tumorigenicity, and tumour growth of TC cells. lncRNA TNRC6C-AS1 was highly expressed while STK4 was poorly expressed in TC tissues. LncRNA TNRC6C-AS1 promoted the STK4 methylation and down-regulated STK4 expression, which further activated the Hippo signalling pathway. STK4 silencing was observed to promote the proliferation ability of TC cells, inhibit the apoptosis and autophagy abilities, as well as enhance the tumorigenicity and tumour growth. Moreover, the in vitro proliferation ability as well as the in vivo tumorigenicity and tumour growth of TC cells were inhibited after the blockade of Hippo signalling pathway, while the apoptosis and autophagy abilities were promoted. The results demonstrate that the lncRNA TNRC6C-AS1 increases STK4 promoter methylation to down-regulate STK4 expression, thereby promoting the development of TC through activation of Hippo signalling pathway. It highlights that lncRNA TNRC6C-AS1 may be a novel therapeutic target for the treatment of TC.

Hsa_Circ_0001206 is downregulated and inhibits cell proliferation, migration and invasion in prostate cancer

Our study is to explore the expression profiles and potential functions of circRNAs in prostate cancer (PCa). A total of 95 circRNAs and 830 mRNAs were screened to be significantly differentially expressed in PCa tissues by microarrays. Co-expression and competitive endogenous RNA (ceRNA) network were constructed to reveal the potential regulatory mechanisms of circRNAs. Three circRNAs, hsa_circ_0001206, hsa_circ_0001633, and hsa_circ_0009061 were validated to be down-regulated in PCa by quantitative real-time PCR (qRT-PCR) and hsa_circ_0001206 as well as hsa_circ_0009061 was significantly associated with clinical features of PCa patients. Meanwhile, Receiver Operating Characteristic (ROC) curves showed their good diagnostic value as biomarkers for PCa. The down-regulation of hsa_circ_001206 was partly because of the regulation of DExH-Box Helicase 9 (DHX9). Moreover, overexpression of hsa_circ_0001206 inhibited PCa cell proliferation, migration, and invasion in vitro and prevented tumor growth in vivo. Dual-luciferase reporter assays showed hsa_circ_0001206 could directly bind to miR-1285-5p. The expression of Smad4, a well-known suppressive gene in PCa, can be increased by overexpression of hsa_circ_0001206 and this effect could be partly reversed by co-transfection of miR-1285-5p mimic. The study revealed expression profiles and potential functions of circRNAs and demonstrated hsa_circ_0001206 played a suppressive role in the pathogenesis of PCa.

An exome-wide rare variant analysis of Korean men identifies three novel genes predisposing to prostate cancer

Since prostate cancer is highly heritable, common variants associated with prostate cancer have been studied in various populations, including those in Korea. However, rare and low-frequency variants have a significant influence on the heritability of the disease. The contributions of rare variants to prostate cancer susceptibility have not yet been systematically evaluated in a Korean population. In this work, we present a large-scale exome-wide rare variant analysis of 7,258 individuals (985 cases with prostate cancer and 6,273 controls). In total, 19 rare variant loci spanning 7 genes contributed to an association with prostate cancer susceptibility. In addition to replicating previously known susceptibility genes (e.g., CDYL2, MST1R, GPER1, and PARD3B), 3 novel genes were identified (FDR q < 0.05), including the non-coding RNAs ENTPD3-AS1, LOC102724438, and protein-coding gene SPATA3. Additionally, 6 pathways were identified based on identified variants and genes, including estrogen signaling pathway, signaling by MST1, IL-15 production, MSP-RON signaling pathway, and IL-12 signaling and production in macrophages, which are known to be associated with prostate cancer. In summary, we report novel genes and rare variants that potentially play a role in prostate cancer susceptibility in the Korean population. These observations demonstrated a path towards one of the fundamental goals of precision medicine, which is to identify biomarkers for a subset of the population with a greater risk of disease than others.

Ventricular Zone Expressed PH Domain Containing 1 (VEPH1): an adaptor protein capable of modulating multiple signaling transduction pathways during normal and pathological development

Ventricular Zone Expressed PH Domain-Containing 1 (VEPH1) is an 833-amino acid protein encoded by an evolutionarily conserved single-copy gene that emerged with pseudocoelomates. This gene has no paralog in any species identified to date and few studies have investigated the function of its encoded protein. Loss of expression of its ortholog, melted, in Drosophila results in a severe neural phenotype and impacts TOR, FoxO, and Hippo signaling. Studies in mammals indicate a role for VEPH1 in modulating TGFβ signaling and AKT activation, while numerous studies indicate VEPH1 expression is altered in several pathological conditions, including cancer. Although often referred to as an uncharacterized protein, available evidence supports VEPH1 as an adaptor protein capable of modulating multiple signal transduction networks. Further studies are required to define these adaptor functions and the role of VEPH1 in development and disease progression.

Suppression of long non-coding RNA TNRC6C-AS1 protects against thyroid carcinoma through DNA demethylation of STK4 via the Hippo signalling pathway

Objectives

Thyroid carcinoma (TC) represents a malignant neoplasm affecting the thyroid. Current treatment strategies include the removal of part of the thyroid; however, this approach is associated with a significant risk of developing hypothyroidism. In order to adequately understand the expression profiles of TNRC6C‐AS1 and STK4 and their potential functions in TC, an investigation into their involvement with Hippo signalling pathway and the mechanism by which they influence TC apoptosis and autophagy were conducted.

Methods

A microarray analysis was performed to screen differentially expressed lncRNAs associated with TC. TC cells were employed to evaluate the role of TNRC6C‐AS1 by over‐expression or silencing means. The interaction of TNRC6C‐AS1 with methylation of STK4 promoter was evaluated to elucidate its ability to elicit autophagy, proliferation and apoptosis.

Results

TNRC6C‐AS1 was up‐regulated while STK4 was down‐regulated, where methylation level was elevated. STK4 was verified as a target gene of TNRC6C‐AS1, which was enriched by methyltransferase. Methyltransferase’s binding to STK4 increased expression of its promoter. Over‐expressed TNRC6C‐AS1 inhibited STK4 by promoting STK4 methylation and reducing the total protein levels of MST1 and LATS1/2. The phosphorylation of YAP1 phosphorylation was decreased, which resulted in the promotion of SW579 cell proliferation and tumorigenicity.

Conclusion

Based on our observations, we subsequently confirmed the anti‐proliferative, pro‐apoptotic and pro‐autophagy capabilities of TNRC6C‐AS1 through STK4 methylation via the Hippo signalling pathway in TC.

Identification of prognostic biomarkers of prostate cancer with long non-coding RNA-mediated competitive endogenous RNA network

Prostate cancer (PCa) is the second most frequently diagnosed male cancer, and no treatments exist for effective inhibition of metastatic spread of PCa. Long non-coding RNA (lncRNA) plays key roles in pathogenesis and development of various cancers through competing with endogenous RNAs (ceRNAs), but at present research on lncRNA functions in PCa is still very limited. Hence, this aspect was investigated using bioinformatics methods. Firstly, the functional lncRNA-mediated ceRNA network associated with PCa was constructed by the multi-step computational approach. Then the cytoscape software was used to analyze the node degree and betweenness centrality (BC) value of lncRNAs and mRNAs in the interaction. Finally, the lncRNAs were screened in the central region of the network by the node degree and BC value, and the functional enrichment of mRNAs was evaluated with the Gene Ontology (GO) database. In our results, LINC00476, MALAT1, SNHG11, LINC00649, and ILF3-AS1 are the lncRNAs which have the most nodes and higher BC values and considered as prognostic markers in PCa. GO analysis suggested that the function of screened lncRNAs was obviously focused on intracellular receptor signaling pathway, which indicated these lncRNAs might be potential biomarkers for diagnosis, evaluation and gene-targeted therapy of PCa.

Inhibition of tankyrase by a novel small molecule significantly attenuates prostate cancer cell proliferation

Tankyrase (TNKS) is a crucial mediator of Wnt signal transduction and has been recognized as a novel molecular target for Wnt-pathway dependent cancer. TNKS is stabilized by the ubiquitin-specific protease 25 (USP25). The effect of disruption of the interaction between TNKS and USP25 by small molecules on prostate cancer proliferation is unknown. In this study we conducted a hierarchical virtual screening with more than 200,000 compounds on the characterized structures of the USP25/TNKS-ARC5 protein complex. In silico analysis and in vitro validation revealed that a small molecule, called C44, binds to the protein-protein interaction (PPI) interface of TNKS and USP25. We show that C44 disrupts the interaction between TNKS and USP25 leading to a higher half-life of AXIN and the breakdown of <beta>-catenin protein. We also show that the selective inhibition of the TNKS-USP25 interaction by C44 significantly reduces proliferation of prostate cancer cells in vitro and in vivo. Our study reveals a new PPI inhibitor that lowers the stability of TNKS protein and inhibits Wnt pathway signaling. C44 is a promising new drug for the treatment of Wnt-pathway dependent prostate cancer.

MST1 inhibits cell proliferation and invasion of non-small-cell lung cancer by regulating YAP phosphorylation and Hippo pathway

Mammalian ste20-like kinase 1 (MST1) is a Ser/Thr kinase involved in cell proliferation, apoptosis, and embryonic development. MST1 is also an important member of the Hippo pathway which can regulate organ size and cell proliferation. Growing evidence indicates that MST1 influences cell proliferation through different pathways including Wnt, Akt, JNK, and Hippo pathways in different cells respectively. However, little is known about the role and mechanism of MST1 in lung cancer. In this study, we aimed to assess the biological functions of MST1 in non-small-cell lung cancer (NSCLC). We investigated expression of MST1 in lung cancer cell lines and one human bronchial epithelium cell line (HBE) by Western blot. The results confirmed that MST1 expression was higher in HBE cells, but significantly lower in NSCLC cells. Moreover, MST1 was either overexpressed or depleted in NSCLC cell lines, and the results confirmed that MST1 could markedly inhibit cell proliferation and invasion through regulating the Hippo pathway and Yes-associated protein (YAP) phosphorylation. These results indicate that MST1 may play an important role in NSCLC and may serve as a potential therapeutic target for NSCLC.