Expression of hippo pathway in colorectal cancer

Advancements of anticancer agents by targeting the Hippo signalling pathway: biological activity, selectivity, docking analysis, and structure-activity relationship

The Hippo signalling pathway is prominent and governs cell proliferation and stem cell activity, acting as a growth regulator and tumour suppressor. Defects in Hippo signalling and hyperactivation of its downstream effector's Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) play roles in cancer development, implying that pharmacological inhibition of YAP and TAZ activity could be an effective cancer treatment strategy. Conversely, YAP and TAZ can also have beneficial effects in promoting tissue repair and regeneration following damage, therefore their activation may be therapeutically effective in certain instances. Recently, a complex network of intracellular and extracellular signalling mechanisms that affect YAP and TAZ activity has been uncovered. The YAP/TAZ-TEAD interaction leads to tumour development and the protein structure of YAP/TAZ-TEAD includes three interfaces and one hydrophobic pocket. There are clinical and preclinical trial drugs available to inhibit the hippo signalling pathway, but these drugs have moderate to severe side effects, so researchers are in search of novel, potent, and selective hippo signalling pathway inhibitors. In this review, we have discussed the hippo pathway in detail, including its structure, activation, and role in cancer. We have also provided the various inhibitors under clinical and preclinical trials, and advancement of small molecules their detailed docking analysis, structure-activity relationship, and biological activity. We anticipate that the current study will be a helpful resource for researchers.

YAP/TAZ-associated cell signaling - at the crossroads of cancer and neurodevelopmental disorders

YAP/TAZ (Yes-associated protein/paralog transcriptional co-activator with PDZ-binding domain) are transcriptional cofactors that are the key and major downstream effectors of the Hippo signaling pathway. Both are known to play a crucial role in defining cellular outcomes, including cell differentiation, cell proliferation, and apoptosis. Aside from the canonical Hippo signaling cascade with the key components MST1/2 (mammalian STE20-like kinase 1/2), SAV1 (Salvador homologue 1), MOB1A/B (Mps one binder kinase activator 1A/B) and LATS1/2 (large tumor suppressor kinase 1/2) upstream of YAP/TAZ, YAP/TAZ activation is also influenced by numerous other signaling pathways. Such non-canonical regulation of YAP/TAZ includes well-known growth factor signaling pathways such as the epidermal growth factor receptor (EGFR)/ErbB family, Notch, and Wnt signaling as well as cell-cell adhesion, cell-matrix interactions and mechanical cues from a cell's microenvironment. This puts YAP/TAZ at the center of a complex signaling network capable of regulating developmental processes and tissue regeneration. On the other hand, dysregulation of YAP/TAZ signaling has been implicated in numerous diseases including various cancers and neurodevelopmental disorders. Indeed, in recent years, parallels between cancer development and neurodevelopmental disorders have become apparent with YAP/TAZ signaling being one of these pathways. This review discusses the role of YAP/TAZ in brain development, cancer and neurodevelopmental disorders with a special focus on the interconnection in the role of YAP/TAZ in these different conditions.

Targeting the Hippo and Rap1 signaling pathways: the anti-proliferative effects of curcumin in colorectal cancer cell lines

CRC has the third-highest cancer incidence and death. Many human cancers, including colorectal cancer, are connected to abnormal signaling pathway gene expression. Many human malignancies include Hippo and Rap1 signaling. This research examined curcumin's therapeutic effects on colorectal cancer cell lines' Hippo and Rap1 signaling pathway genes. The role of the above signaling pathways is considered in colorectal cancer development. No research has examined curcumin's influence on key genes in these pathways; thus, this work is meant to uncover its more precise mechanism. First, the gene expression omnibus database is queried to discover GSE8671, a dataset that contains differentially expressed genes associated in CRC formation. DAVID was used to discover the corporation of these genes and signaling pathways (Hippo and Rap1), and the cancer genome atlas (TCGA) database was utilized to select genes and assess their expression and biomarker potential. MTT, apoptosis, and quantitative PCR were used to assess whether curcumin is therapeutic for colorectal cancer cell lines. An in-silico analysis identified the dysregulation of several critical genes AXIN2, MYC, TEAD4, MET, LPAR1, and ADCY9 in colorectal cancer, highlighting their involvement in the Hippo and Rap1 signaling pathways. Experimental assessments, including MTT assays, apoptosis assays, and quantitative PCR (qPCR) analysis, demonstrated that the targeted modulation of these genes effectively inhibits cancer cell proliferation. Specifically, treatment with curcumin resulted in a significant reduction in cell viability in HT-29 and HCT-116 colorectal cancer cell lines, thereby facilitating apoptotic cell death. Furthermore, curcumin administration was associated with the upregulation of LPAR1 and ADCY9 gene expression, while concurrently downregulating AXIN2, MYC, TEAD4, and MET in both cell lines. This study reveals compelling evidence of curcumin's potent anticancer properties, highlighting its transformative influence on the Hippo and Rap1 signaling pathways within colorectal cancer cells. These findings not only underscore curcumin's potential as a therapeutic agent but also pave the way for innovative strategies in the fight against colorectal cancer.

Substrate stiffness-dependent activation of Hippo pathway in cancer associated fibroblasts

The tumor microenvironment (TME) comprises a heterogenous cell population within a complex three-dimensional (3D) extracellular matrix (ECM). Stromal cells within this TME are altered by signaling cues from cancer cells to support uncontrolled tumor growth and invasion events. Moreover, the ECM also plays a fundamental role in tumor development through pathological remodeling, stiffening and interaction with TME cells. In healthy tissues, Hippo signaling pathway actively contributes to tissue growth, cell proliferation and apoptosis. However, in cancer, the Hippo signaling pathway is highly dysregulated, leading to nuclear translocation of the YAP/TAZ complex, which directly contributes to uncontrolled cell proliferation and tissue growth, and ECM remodeling and stiffening processes. Here, we compare the effect of increasing cell culture substrate stiffness, derived from tumor progression, upon the dysregulation of the Hippo signaling pathway in colorectal cancer-associated fibroblasts (CAFs) and normal colorectal fibroblasts (NFs). We correlate the dysregulation of Hippo pathway with the magnitude of the traction forces exerted by healthy and malignant stromal cells. We found that ECM stiffening is crucial in Hippo pathway dysregulation in CAFs, but not in normal fibroblasts.

TEAD transcription factor family emerges as a promising therapeutic target for oral squamous cell carcinoma

The treatment of oral squamous cell carcinoma (OSCC) remains a significant difficulty, as there has been no improvement in survival rates over the past fifty years. Hence, exploration and confirmation of new dependable treatment targets and biomarkers is imperative for OSCC therapy. TEAD transcription factors are crucial for integrating and coordinating multiple signaling pathways that are essential for embryonic development, organ formation, and tissue homeostasis. In addition, by attaching to coactivators, TEAD modifies the expression of genes such as Cyr61, Myc, and connective tissue growth factor, hence facilitating tumor progression. Therefore, TEAD is regarded as an effective predictive biomarker due to its significant connection with clinical parameters in several malignant tumors, including OSCC. The efficacy of existing drugs that specifically target TEAD has demonstrated encouraging outcomes, indicating its potential as an optimal target for OSCC treatment. This review provides an overview of current targeted therapy strategies for OSCC by highlighting the transcription mechanism and involvement of TEAD in oncogenic signaling pathways. Finally, the feasibility of utilizing TEAD as an innovative approach to address OSCC and its potential clinical applications were analyzed and discussed.

Hippo pathway effectors YAP, TAZ and TEAD are associated with EMT master regulators ZEB, Snail and with aggressive phenotype in phyllodes breast tumors

BACKGROUND

Phyllodes tumors (PTs) of the breast are uncommon fibroepithelial neoplasms that tend to recur locally and may have metastatic potential. Their pathogenesis is poorly understood. Hippo signaling pathway plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. Hippo signaling dysfunction has been implicated in cancer. Recent evidence suggests that there is cross-talk between the Hippo signaling key proteins YAP/TAZ and the epithelial-mesenchymal transition (EMT) master regulators Snail and ZEB. In this study we aimed to investigate the expression of Hippo signaling pathway components and EMT regulators in PTs, in relation to tumor grade.

METHODS

Expression of Hippo signaling effector proteins YAP, TAZ and their DNA binding partner TEAD was evaluated by immunohistochemistry in paraffin-embedded tissue specimens from 86 human phyllodes breast tumors (45 benign, 21 borderline, 20 malignant), in comparison with tumor grade and with the expression of EMT-related transcription factors ZEB and Snail.

RESULTS

Nuclear immunopositivity for YAP, TAZ and TEAD was detected in both stromal and epithelial cells in PTs and was significantly higher in high grade tumors. Interestingly, there was a significant correlation between the expression of YAP, TAZ, TEAD and the expression of ZEB and SNAIL.

CONCLUSIONS

Our results originally implicate Hippo signaling pathway in PTs pathogenesis and suggest that an interaction between Hippo signaling key components and EMT regulators may promote the malignant features of PTs.

Investigating the Effects of AL049796.1 Silencing in Inhibiting High Glucose-Induced Colorectal Cancer Progression

Patients with colorectal cancer (CRC) and diabetes share many risk factors. Despite a strong association between diabetes and CRC being widely studied and confirmed, further genetic research is needed. This study found higher AL049796.1 and TEA domain transcription factor 1 (TEAD1) levels (both mRNA and protein) in CRC tissues of diabetic patients compared with nondiabetics, but no significant difference in miR-200b-3p levels. A positive correlation between AL049796.1 and TEAD1 protein existed regardless of diabetes status, whereas miR-200b-3p was only negatively correlated with TEAD1 protein in nondiabetic CRC tissues. In vitro experiments have shown that high glucose (HG) treatment increased AL049796.1 in CRC cells, and AL049796.1 silencing reduced HG-induced proliferation, migration and invasion, as well as connective tissue growth factor, cysteine-rich angiogenic inducer 61, and epidermal growth factor receptor protein expression. Mechanistic investigations indicated that AL049796.1 could mitigate suppression of miR-200b-3p on TEAD1 posttranscriptionally by acting as a competitive binder. In vivo, subcutaneous CRC tumors in streptozotocin (STZ)-induced mice grew significantly faster; AL049796.1 silencing did not affect the growth of subcutaneous CRC tumors but significantly reduced that of STZ-induced mice. Our study suggests that AL049796.1 independently contributes to the risk of CRC in diabetic patients, highlighting its potential as both a therapeutic target and a novel biomarker for CRC among individuals with diabetes.

Blood miRNAs miR-549a, miR-552, and miR-592 serve as potential disease-specific panels to diagnose colorectal cancer

Introduction

miRNAs originating from colorectal cancer (CRC) tissue receive significant focus in the early diagnosis of CRC due to their stability in body fluids. However, if these miRNAs originated from alternative organs, their prognostic value will diminish. Thus, in this study, we aim to identify disease-specific miRNAs for colorectal cancer (CRC) by employing bioinformatics and experimental methodologies.

Method

To identify CRC-specific miRNAs, we retrieved miRNA profiles of CRC and normal tissues from the Cancer Genome Atlas (TCGA) database. Subsequently, computational strategies were utilized to select potential candidate miRNAs. Following this, the expression levels of the potent miRNAs were assessed through RT-qPCR in both CRC tissue and serum samples from patients (N = 46), as well as healthy individuals (N = 46). Additionally, the associations between clinicopathological characteristics, survival outcomes, and diagnostic accuracy were evaluated.

Results

A total of 8893 RNA-seq expression data were acquired from TCGA, comprising 8250 data from 19 distinct cancer types and 643 corresponding healthy samples. Based on the computational methodology, miR-549a, miR-552, and miR-592 were identified as the principal expressed miRNAs in colorectal cancer (CRC). Within these miRNAs, miR-552 displayed a substantial association with tumors at the N and T stages. miR-549a and miR-592 were observed to be linked exclusively to the invasion of tumor depth and tumor stage (TNM), respectively. The receiver operating characteristic (ROC) analysis conducted on the miRNA expression in serum samples revealed that all miRNAs exhibited an area under the ROC curve (AUC) of up to 0.86, thereby indicating their high diagnostic accuracy.

Conclusion

Considering the strong associations of these three identified miRNAs with CRC, they can collectively serve as a panel for specific discrimination of CRC from other types of cancer within the body. Although this study focused solely on CRC, this approach can potentially be applied to other cancer types as well.

Weighted Combination of Łukasiewicz implication and Fuzzy Jaccard similarity in Hybrid Ensemble Framework (WCLFJHEF) for Gene Selection

A framework is developed for gene expression analysis by introducing fuzzy Jaccard similarity (FJS) and combining Łukasiewicz implication with it through weights in hybrid ensemble framework (WCLFJHEF) for gene selection in cancer. The method is called weighted combination of Łukasiewicz implication and fuzzy Jaccard similarity in hybrid ensemble framework (WCLFJHEF). While the fuzziness in Jaccard similarity is incorporated by using the existing Gödel fuzzy logic, the weights are obtained by maximizing the average F-score of selected genes in classifying the cancer patients. The patients are first divided into different clusters, based on the number of patient groups, using average linkage agglomerative clustering and a new score, called WCLFJ (weighted combination of Łukasiewicz implication and fuzzy Jaccard similarity). The genes are then selected from each cluster separately using filter based Relief-F and wrapper based SVMRFE (Support Vector Machine with Recursive Feature Elimination). A gene (feature) pool is created by considering the union of selected features for all the clusters. A set of informative genes is selected from the pool using sequential backward floating search (SBFS) algorithm. Patients are then classified using Naïve Bayes'(NB) and Support Vector Machine (SVM) separately, using the selected genes and the related F-scores are calculated. The weights in WCLFJ are then updated iteratively to maximize the average F-score obtained from the results of the classifier. The effectiveness of WCLFJHEF is demonstrated on six gene expression datasets. The average values of accuracy, F-score, recall, precision and MCC over all the datasets, are 95%, 94%, 94%, 94%, and 90%, respectively. The explainability of the selected genes is shown using SHapley Additive exPlanations (SHAP) values and this information is further used to rank them. The relevance of the selected gene set are biologically validated using the KEGG Pathway, Gene Ontology (GO), and existing literatures. It is seen that the genes that are selected by WCLFJHEF are candidates for genomic alterations in the various cancer types. The source code of WCLFJHEF is available at http://www.isical.ac.in/~shubhra/WCLFJHEF.html.

Impaired Expression of the Salvador Homolog-1 Gene Is Associated with the Development and Progression of Colorectal Cancer

Salvador homolog-1 (SAV1) is a component of the Hippo pathway that regulates tissue growth and homeostasis by affecting diverse cell processes, including apoptosis, cell division, and differentiation. The aberrant expression of Hippo pathway components has been observed in various human cancers. This study aimed to examine the expression level of the SAV1 gene in colorectal cancer (CRC) and its prognostic value and associations with tumor progression. We obtained matched pairs of tumor tissue and non-cancerous mucosa of the large intestine from 94 CRC patients as well as 40 colon biopsies of healthy subjects collected during screening colonoscopy. The tissue samples and CRC cell lines were quantified for SAV1 mRNA levels using the quantitative polymerase chain reaction method, while SAV1 protein expression was estimated in the paired tissues of CRC patients using immunohistochemistry. The average level of SAV1 mRNA was decreased in 93.6% of the tumor tissues compared to the corresponding non-cancerous tissues and biopsies of healthy colon mucosa. A downregulated expression of SAV1 mRNA was also noted in the CRC cell lines. Although the average SAV1 immunoreactivity was increased in the CRC samples compared to the non-cancerous tissues, a decreased immunoreactivity of the SAV1 protein in the tumor specimens was associated with lymph node involvement and higher TNM disease stage and histological grade. The results of our study suggest that the impaired expression of SAV1 is involved in CRC progression.

Integrative deep learning analysis improves colon adenocarcinoma patient stratification at risk for mortality

BACKGROUND

Colorectal cancers are the fourth most diagnosed cancer and the second leading cancer in number of deaths. Many clinical variables, pathological features, and genomic signatures are associated with patient risk, but reliable patient stratification in the clinic remains a challenging task. Here we assess how image, clinical, and genomic features can be combined to predict risk.

METHODS

We developed and evaluated integrative deep learning models combining formalin-fixed, paraffin-embedded (FFPE) whole slide images (WSIs), clinical variables, and mutation signatures to stratify colon adenocarcinoma (COAD) patients based on their risk of mortality. Our models were trained using a dataset of 108 patients from The Cancer Genome Atlas (TCGA), and were externally validated on newly generated dataset from Wayne State University (WSU) of 123 COAD patients and rectal adenocarcinoma (READ) patients in TCGA (N = 52).

FINDINGS

We first observe that deep learning models trained on FFPE WSIs of TCGA-COAD separate high-risk (OS < 3 years, N = 38) and low-risk (OS > 5 years, N = 25) patients (AUC = 0.81 ± 0.08, 5 year survival p < 0.0001, 5 year relative risk = 1.83 ± 0.04) though such models are less effective at predicting overall survival (OS) for moderate-risk (3 years < OS < 5 years, N = 45) patients (5 year survival p-value = 0.5, 5 year relative risk = 1.05 ± 0.09). We find that our integrative models combining WSIs, clinical variables, and mutation signatures can improve patient stratification for moderate-risk patients (5 year survival p < 0.0001, 5 year relative risk = 1.87 ± 0.07). Our integrative model combining image and clinical variables is also effective on an independent pathology dataset (WSU-COAD, N = 123) generated by our team (5 year survival p < 0.0001, 5 year relative risk = 1.52 ± 0.08), and the TCGA-READ data (5 year survival p < 0.0001, 5 year relative risk = 1.18 ± 0.17). Our multicenter integrative image and clinical model trained on combined TCGA-COAD and WSU-COAD is effective in predicting risk on TCGA-READ (5 year survival p < 0.0001, 5 year relative risk = 1.82 ± 0.13) data. Pathologist review of image-based heatmaps suggests that nuclear size pleomorphism, intense cellularity, and abnormal structures are associated with high-risk, while low-risk regions have more regular and small cells. Quantitative analysis shows high cellularity, high ratios of tumor cells, large tumor nuclei, and low immune infiltration are indicators of high-risk tiles.

INTERPRETATION

The improved stratification of colorectal cancer patients from our computational methods can be beneficial for treatment plans and enrollment of patients in clinical trials.

FUNDING

This study was supported by the National Cancer Institutes (Grant No. R01CA230031 and P30CA034196). The funders had no roles in study design, data collection and analysis or preparation of the manuscript.

Platycodin D confers oxaliplatin Resistance in Colorectal Cancer by activating the LATS2/YAP1 axis of the hippo signaling pathway

Oxaliplatin-based therapy is used as a first-line drug to treat metastatic colorectal cancer. However, long-term and repeated drug treatment resulted in drug resistance and the failure of chemotherapy. Various natural compounds were previously reported to act as chemosensitizers to reverse drug resistance. In this study, we found that platycodin D (PD), a saponin found in Platycodon grandiflorum, inhibited LoVo and OR-LoVo cells proliferation, invasion, and migration ability. Our results indicated that combined treatment of oxaliplatin with PD dramatically reduced the cellular proliferation in both LoVo and OR-LoVo cells. Furthermore, treatment with PD dose-dependently decreased LATS2/YAP1 hippo signaling and survival marker p-AKT expression, as well as increased cyclin-dependent kinase inhibitor proteins such as p21 and p27 expression. Importantly, PD activates and promotes YAP1 degradation through the ubiquitination and proteasome pathway. The nuclear transactivation of YAP was significantly reduced under PD treatment, leading to transcriptional inhibition of the downstream genes regulating cell proliferation, pro-survival, and metastasis. In conclusion, our results showed that PD is suitable as a promising agent for overcoming oxaliplatin-resistant colorectal cancer.

Expression of the Hippo Pathway Core Components in Endometrial Cancer and Its Association with Clinicopathologic Features

BACKGROUND

The Hippo signaling pathway has a key role in tumorigenesis. This study aimed to evaluate the relationship between the expression of core components of the Hippo signaling pathway and its association with clinicopathological features in endometrial cancer.

MATERIALS AND METHODS

We retrospectively collected endometrioid endometrial cancer specimens from 60 patients between January 2002 and December 2009 at Gyeongsang National University Hospital. Relevant clinicopathological data were obtained through electronic medical records of patients. The expression patterns of six core components (YAP, p-YAP, LATS1/2, MST1/2, KIBRA, and Merlin) were identified by immunohistochemistry on tissue microarray sections.

RESULTS

The positive expression ratio was 75.0% for YAP, 73.3% for p-YAP, 26.7% for MST1/2, 16.7% for KIBRA, 15.0% for Merlin, and 15.0% for LATS1/2. YAP expression was negatively correlated with MST 1/2 kinases (p = 0.045) and positively correlated with p-YAP (p = 0.012). Merlin, and MST 1/2 kinases (p = 0.043) showed a positive correlation. A subgroup of patients aged below 60 years (p = 0.004) and with myometrial invasion depth of less than 1/2 (p = 0.041) showed a positive association with YAP expression. p-YAP expression was negatively associated with a subset of patients with primary tumour size ≥4 cm (p = 0.03). Logistic regression analysis showed a significant association between age and YAP expression. The odds ratio of p-YAP expression was significantly lower in the group with tumour size ≥4 cm.

CONCLUSION

Two prognostic factors, age and tumour size, were significantly associated with the expression of YAP and p-YAP in endometrial cancer. Further research should focus on their expression as a marker for prediction of clinicopathological implications in endometrial cancer.

Targeting the Hippo Pathway in Gastric Cancer and Other Malignancies in the Digestive System: From Bench to Bedside

The Hippo pathway is an evolutionally conserved signaling cascade that controls organ size and tissue regeneration under physiological conditions, and its aberrations have been well studied to promote tumor initiation and progression. Dysregulation of the Hippo tumor suppressor signaling frequently occurs in gastric cancer (GC) and other solid tumors and contributes to cancer development through modulating multiple aspects, including cell proliferation, survival, metastasis, and oncotherapy resistance. In the clinic, Hippo components also possess diagnostic and prognostic values for cancer patients. Considering its crucial role in driving tumorigenesis, targeting the Hippo pathway may greatly benefit developing novel cancer therapies. This review summarizes the current research progress regarding the core components and regulation of the Hippo pathway, as well as the mechanism and functional roles of their dysregulation in gastrointestinal malignancies, especially in GC, and discusses the therapeutic potential of targeting the Hippo pathway against cancers.

A pan-cancer analysis of FAT atypical cadherin 4 (FAT4) in human tumors

Objective

We performed a pan-cancer analysis to explore the potential mechanisms of FAT4 in 33 different tumors.

Methods

In this study, we selected 33 types of cancers based on the datasets of TCGA (the cancer genome atlas). We analyzed the expression of FAT4 in tumor and normal tissues. Meanwhile, we analyzed the expression levels of FAT4 in tissues from tumors of different stages. Kaplan-Meier survival analysis, Tumor Mutational Burden (TMB), Microsatellite Instability (MSI), immune infiltration analysis, Gene set enrichment analysis (GSEA), and FAT4-related gene enrichment analysis were performed.

Results

FAT4 expression in most tumor tissues was lower than in corresponding control tissues. FAT4 expression was different in different stages of bladder cancer (BLCA), kidney clear cell carcinoma (KIRC), and breast cancer (BRCA). In addition, the expression level of FAT4 in different types of tumors has an important impact on the prognosis of patients. FAT4 might influence the efficacy of immunotherapy via tumor burden and microsatellite instability. We observed a statistically positive correlation between cancer-associated fibroblasts and FAT4 expression in most tumors. GSEA of BLCA indicated that low FAT4 expression groups were mainly enriched in calcium signaling pathway and chemokine signaling pathway. GSEA analysis of KIRC suggested low FAT4 expression groups were mainly involved in olfactory transduction and oxidative phosphorylation. Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that the role of FAT4 in the pathogenesis of cancer may be related to human papillomavirus infection, Hippo signaling pathway, PI3K-Akt signaling pathway, etc. Gene Ontology (GO) enrichment analysis further showed that most of these genes were related to the pathways or cell biology, such as peptidyl-tyrosine phosphorylation, cell junction assembly, protein tyrosine kinase activity, etc.

Conclusion

Our study summarized and analyzed the antitumor effect of FAT4 in different tumors comprehensively, which aided in understanding the role of FAT4 in tumorigenesis from the perspective of clinical tumor samples. Pan-cancer analysis showed that FAT4 to be novel biomarkers for various cancers prognosis.

Downregulation of miR-335 exhibited an oncogenic effect via promoting KDM3A/YAP1 networks in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cancer affecting many people worldwide. Although the 5-year survival rate is 65% in localized disease, after metastasis, the survival rate is <10%. Emerging evidence has shown that microRNAs (miRNAs) play a crucial regulatory role in the progression of ccRCC. Here, we show that miR-335, an anti-onco-miRNA, is downregulation in tumor tissue and inhibited ccRCC cell proliferation, invasion, and migration. Our studies further identify the H3K9me1/2 histone demethylase KDM3A as a new miR-335-regulated gene. We show that KDM3A is overexpressed in ccRCC, and its upregulation contributes to the carcinogenesis and metastasis of ccRCC. Moreover, with the overexpression of KDM3A, YAP1 was increased and identified as a direct downstream target of KDM3A. Enrichment of KDM3A demethylase on YAP1 promoter was confirmed by CHIP-qPCR and YAP1 was also found involved in the cell growth and metastasis inhibitory of miR-335. Together, our study establishes a new miR-335/KDM3A/YAP1 regulation axis, which provided new insight and potential targeting of the metastasized ccRCC.

Morphogen regulation of stem cell plasticity in intestinal regeneration and carcinogenesis

The intestinal epithelium is a tissue with high cell turnover, supported by adult intestinal stem cells. Intestinal homeostasis is underpinned by crypt basal columnar stem cells, marked by expression of the LGR5 gene. However, recent research has demonstrated considerable stem cell plasticity following injury, with dedifferentiation of a range of other intestinal cell populations, induced by a permissive microenvironment in the regenerating mucosa. The regulation of this profound adaptive cell reprogramming response is the subject of current research. There is a demonstrable contribution from disruption of key homeostatic signaling pathways such as wingless-related integration site and bone morphogenetic protein, and an emerging signaling hub role for the mechanoreceptor transducers Yes-associated protein 1/transcriptional coactivator with PDZ-binding motif, negatively regulated by the Hippo pathway. However, a number of outstanding questions remain, including a need to understand how tissues sense damage, and how pathways intersect to mediate dynamic changes in the stem cell population. Better understanding of these pathways, associated functional redundancies, and how they may be both enhanced for recovery of inflammatory diseases, and co-opted in neoplasia development, may have significant clinical implications, and could lead to development of more targeted molecular therapies which target individual stem or stem-like cell populations.

The Hippo signaling pathway in leukemia: function, interaction, and carcinogenesis

Cancer can be considered as a communication disease between and within cells; nevertheless, there is no effective therapy for the condition, and this disease is typically identified at its late stage. Chemotherapy, radiation, and molecular-targeted treatment are typically ineffective against cancer cells. A better grasp of the processes of carcinogenesis, aggressiveness, metastasis, treatment resistance, detection of the illness at an earlier stage, and obtaining a better therapeutic response will be made possible. Researchers have discovered that cancerous mutations mainly affect signaling pathways. The Hippo pathway, as one of the main signaling pathways of a cell, has a unique ability to cause cancer. In order to treat cancer, a complete understanding of the Hippo signaling system will be required. On the other hand, interaction with other pathways like Wnt, TGF-β, AMPK, Notch, JNK, mTOR, and Ras/MAP kinase pathways can contribute to carcinogenesis. Phosphorylation of oncogene YAP and TAZ could lead to leukemogenesis, which this process could be regulated via other signaling pathways. This review article aimed to shed light on how the Hippo pathway interacts with other cellular signaling networks and its functions in leukemia.

Mesenchymal stem/stromal cells in cancer therapy

The multipotent mesenchymal stem/stromal cells (MSCs), initially discovered from bone marrow in 1976, have been identified in nearly all tissues of human body now. The multipotency of MSCs allows them to give rise to osteocytes, chondrocytes, adipocytes, and other lineages. Moreover, armed with the immunomodulation capacity and tumor-homing property, MSCs are of special relevance for cell-based therapies in the treatment of cancer. However, hampered by lack of knowledge about the controversial roles that MSC plays in the crosstalk with tumors, limited progress has been made with regard to translational medicine. Therefore, in this review, we discuss the prospects of MSC-associated anticancer strategies in light of therapeutic mechanisms and signal transduction pathways. In addition, the clinical trials designed to appraise the efficacy and safety of MSC-based anticancer therapies will be assessed according to published data.

Reciprocal Regulation of Hippo and WBP2 Signalling-Implications in Cancer Therapy

Cancer is a global health problem. The delineation of molecular mechanisms pertinent to cancer initiation and development has spurred cancer therapy in the form of precision medicine. The Hippo signalling pathway is a tumour suppressor pathway implicated in a multitude of cancers. Elucidation of the Hippo pathway has revealed an increasing number of regulators that are implicated, some being potential therapeutic targets for cancer interventions. WW domain-binding protein 2 (WBP2) is an oncogenic transcriptional co-factor that interacts, amongst others, with two other transcriptional co-activators, YAP and TAZ, in the Hippo pathway. WBP2 was recently discovered to modulate the upstream Hippo signalling components by associating with LATS2 and WWC3. Exacerbating the complexity of the WBP2/Hippo network, WBP2 itself is reciprocally regulated by Hippo-mediated microRNA biogenesis, contributing to a positive feedback loop that further drives carcinogenesis. Here, we summarise the biological mechanisms of WBP2/Hippo reciprocal regulation and propose therapeutic strategies to overcome Hippo defects in cancers through targeting WBP2.

Colon Cancer Progression Is Reflected to Monotonic Differentiation in Gene Expression and Pathway Deregulation Facilitating Stage-specific Drug Repurposing

BACKGROUND/AIM

Colon cancer is one of the most common cancer types and the second leading cause of death due to cancer. Many efforts have been performed towards the investigation of molecular alterations during colon cancer progression. However, the identification of stage-specific molecular markers remains a challenge. The aim of this study was to develop a novel computational methodology for the analysis of alterations in differential gene expression and pathway deregulation across colon cancer stages in order to reveal stage-specific biomarkers and reinforce drug repurposing investigation.

MATERIALS AND METHODS

Transcriptomic datasets of colon cancer were used to identify (a) differentially expressed genes with monotonicity in their fold changes (MEGs) and (b) perturbed pathways with ascending monotonic enrichment (MEPs) related to the number of the participating differentially expressed genes (DEGs), across the four colon cancer stages. Through an in silico drug repurposing pipeline we identified drugs that regulate the expression of MEGs and also target the resulting MEPs.

RESULTS

Our methodology highlighted 15 MEGs and 32 candidate repurposed drugs that affect their expression. We also found 51 MEPs divided into two groups according to their rate of DEG content alteration across colon cancer stages. Focusing on the target MEPs of the highlighted repurposed drugs, we found that one of them, the neuroactive ligand-receptor interaction, was targeted by the majority of the candidate drugs. Moreover, we observed that two of the drugs (PIK-75 and troglitazone) target the majority of the resulting MEPs.

CONCLUSION

These findings highlight significant genes and pathways that can be used as stage-specific biomarkers and facilitate the discovery of new potential repurposed drugs for colon cancer. We expect that the computational methodology presented can be applied in a similar way to the analysis of any progressive disease.

Expression of mammalian sterile 20-like kinase 1 and 2 and Yes-associated protein 1 proteins in triple-negative breast cancer and the clinicopathological significance

BACKGROUND AND AIM

Mammalian sterile 20-like kinase 1 and 2 (MST1/2) and Yes-associated protein 1 (YAP1) are the core molecules of the Hippo signaling pathway, which have been found to be unbalanced in the occurrence of tumors and promote the development of the lesions. The present study aimed to investigate the expression of MST1/2 and YAP1 proteins in triple-negative breast cancer (TNBC) and their clinicopathological significance.

METHODS

Immunohistochemistry was used to detect the expression level of protein in tissues. According to the percentage of positive cells and staining intensity, the expression intensity of MST1/2 and YAP1 proteins in the tissue samples was scored, and the correlation between MST1/2 and the clinicopathological features of TNBC were discussed.

RESULTS

The expression of MST1/2 and YAP1 was associated with histological grade, metastasis, lymph node metastasis stage, and tumor node metastasis stage. The overexpression of YAP1 predicted a poor prognosis in terms of overall survival and disease-free survival time. The MST1/2 expression was associated with improved overall survival and disease free survival of the patients.

CONCLUSION

MST1/2 and YAP1 may be used as prognostic indicators to evaluate the recurrence of TNBC and might become one of the new targets for breast cancer treatment.

The two sides of Hippo pathway in cancer

The Hippo signaling pathway was originally characterized by genetic studies in Drosophila to regulate tissue growth and organ size, and the core components of this pathway are highly conserved in mammals. Studies over the past two decades have revealed critical physiological and pathological functions of the Hippo tumor-suppressor pathway, which is tightly regulated by a broad range of intracellular and extracellular signals. These properties enable the Hippo pathway to serve as an important controller in organismal development and adult tissue homeostasis. Dysregulation of the Hippo signaling has been observed in many cancer types, suggesting the possibility of cancer treatment by targeting the Hippo pathway. The general consensus is that Hippo has tumor suppressor function. However, growing evidence also suggests that the function of the Hippo pathway in malignancy is cancer context dependent as recent studies indicating tumor promoting function of LATS. This article surveys the Hippo pathway signaling mechanisms and then reviews both the tumor suppressing and promoting function of this pathway. A comprehensive understanding of the dual roles of the Hippo pathway in cancer will benefit future therapeutic targeting of the Hippo pathway for cancer treatment.

Hippo pathway: Regulation, deregulation and potential therapeutic targets in cancer

Hippo pathway is a master regulator of development, cell proliferation, stem cell function, tissue regeneration, homeostasis, and organ size control. Hippo pathway relays signals from different extracellular and intracellular events to regulate cell behavior and functions. Hippo pathway is conserved from Protista to eukaryotes. Deregulation of the Hippo pathway is associated with numerous cancers. Alteration of the Hippo pathway results in cell invasion, migration, disease progression, and therapy resistance in cancers. However, the function of the various components of the mammalian Hippo pathway is yet to be elucidated in detail especially concerning tumor biology. In the present review, we focused on the Hippo pathway in different model organisms, its regulation and deregulation, and possible therapeutic targets for cancer treatment.

A review: hippo signaling pathway promotes tumor invasion and metastasis by regulating target gene expression

BACKGROUND

The Hippo pathway is widely considered to inhibit cell growth and play an important role in regulating the size of organs. However, recent studies have shown that abnormal regulation of the Hippo pathway can also affect tumor invasion and metastasis. Therefore, finding out how the Hippo pathway promotes tumor development by regulating the expression of target genes provides new ideas for future research on targeted drugs that inhibit tumor progression.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched.

RESULTS

The search strategy identified 1892 hits and 196 publications were finally included in this review. As the core molecule of the Hippo pathway, YAP/TAZ are usually highly expressed in tumors that undergo invasion and migration and are accompanied by abnormally strong nuclear metastasis. Through its interaction with nuclear transcription factors TEADs, it directly or indirectly regulates and the expressions of target genes related to tumor metastasis and invasion. These target genes can induce the formation of invasive pseudopodia in tumor cells, reduce intercellular adhesion, degrade extracellular matrix (ECM), and cause epithelial-mesenchymal transition (EMT), or indirectly promote through other signaling pathways, such as mitogen-activated protein kinases (MAPK), TGF/Smad, etc, which facilitate the invasion and metastasis of tumors.

CONCLUSION

This article mainly introduces the research progress of YAP/TAZ which are the core molecules of the Hippo pathway regulating related target genes to promote tumor invasion and metastasis. Focus on the target genes that affect tumor invasion and metastasis, providing the possibility for the selection of clinical drug treatment targets, to provide some help for a more in-depth study of tumor invasion and migration mechanism and the development of clinical drugs.

Association of subcellular localization of TEAD transcription factors with outcome and progression in pancreatic ductal adenocarcinoma

BACKGROUND

Transcriptional enhanced associated domain (TEAD) transcription factors are nuclear effectors of several oncogenic signalling pathways including Hippo, WNT, TGF-ß and EGFR pathways that interact with various cancer genes. The subcellular localization of TEAD regulates the functional output of these pathways affecting tumour progression and patient outcome. However, the impact of the TEAD family on pancreatic ductal adenocarcinoma (PDAC) and its clinical progression remain elusive.

METHODS

A cohort of 81 PDAC patients who had undergone surgery was established. Cytoplasmic and nuclear localization of TEAD1, TEAD2, TEAD3 and TEAD4 was evaluated with the immunoreactive score (IRS) by immunohistochemistry (IHC) using paraffin-embedded tissue. Results were correlated with clinicopathological data, disease-free and overall survival.

RESULTS

Nuclear staining of all four TEADs was increased in pancreatic cancer tissue. Patients suffering from metastatic disease at time of surgery showed a strong nuclear staining of TEAD2 and TEAD3 (p < 0.05). Furthermore, a nuclear > cytoplasmic ratio of TEAD2 and TEAD3 was associated with a shorter overall survival and TEAD2 emerged as an independent prognostic factor for disease-free survival.

CONCLUSION

Our study underlines the importance of TEAD transcription factors in PDAC as a nuclear localization was found to be associated with metastatic disease and an unfavourable prognosis after surgical resection.

The Role and Specific Mechanism of OCT4 in Cancer Stem Cells: A Review

Recently, evidences show that cancer stem cells (CSCs) are a type of cancer cell group with self-renewal and play a huge role in tumor recurrence, metastasis, and drug resistance. Finding new treatment directions and targets for cancer prognosis and reducing mortality has become a top priority. OCT4, as a transcription factor, participates in maintaining the stem characteristics of CSCs, but the mechanism of OCT4 is often overlooked. In this review, we try to illustrate the mechanism by which OCT4 plays a role in CSCs from the perspective of genetic modification of OCT4, non-coding RNA, complexes and signaling pathways associated with OCT4. Our ultimate goal is to provide new targets for cancer treatment to prolong the survival of cancer patients.

Regulation of Hippo signaling pathway in cancer: A MicroRNA perspective

Recent studies have suggested that Hippo signaling is not only involved in controlling organ size in Drosophila but can also regulate cell proliferation, tissue homeostasis, differentiation, apoptosis and regeneration. Any dysregulation of Hippo signaling, especially the hyper activation of its downstream effectors YAP/TAZ, can lead to uncontrolled cell proliferation and malignant transformation. In majority of cancers, expression of YAP/TAZ is extremely high and this increased expression of YAP/TAZ has been shown to be an independent predictor of prognosis and indicator of increased cell proliferation, metastasis and poor survival. In this review, we have summarized the most recent findings about the cross talk of Hippo signaling pathway with other signaling pathways and its regulation by different miRNAs in various cancer types. Recent evidence has suggested that Hippo pathway is also involved in mediating the resistance of different cancer cells to chemotherapeutic drugs and in a few cancer types, this is brought about by regulating miRNAs. Therefore, the delineation of the underlying mechanisms regulating the chemotherapeutic resistance might help in developing better treatment options. This review has attempted to provide an overview of different drugs/options which can be utilized to target oncogenic YAP/TAZ proteins for therapeutic interventions.

Immortalization up-regulated protein promotes tumorigenesis and inhibits apoptosis of papillary thyroid cancer

The incidence of thyroid cancer is increasing in recent years worldwide, but the underlying mechanisms await further exploration. We utilized the bioinformatic analysis to discover that Immortalization up‐regulated protein (IMUP) could be a potential oncogene in the papillary thyroid cancer (PTC). We verified this finding in several databases and locally validated cohorts. Clinicopathological features analyses showed that high expression of IMUP is positively related to malignant clinicopathological features in PTC. Braf‐like PTC patients with higher IMUP expression had shorter disease‐free survival. The biological function of IMUP in PTC cell lines (KTC‐1 and TPC‐1) was investigated using small interfering RNA. Our results showed that silencing IMUP suppresses proliferation, migration and invasion while inducing apoptosis in PTC cell lines. Changes of the expression of apoptosis‐related molecules were identified by real‐time quantitative polymerase chain reaction and Western blotting. We also found that YAP1 and TAZ, the critical effectors in the Hippo pathway, were down‐regulated when the IMUP is silenced. Rescue experiments showed that overexpression of YAP1 reverses the tumour inhibitory effect caused by IMUP knockdown. Our study demonstrated that IMUP has an oncogenic function in PTC and might be a new target gene in the treatment of PTC.

Therapeutic Targeting of Signaling Pathways Related to Cancer Stemness

The theory of cancer stem cells (CSCs) proposes that the different cells within a tumor, as well as metastasis deriving from it, are originated from a single subpopulation of cells with self-renewal and differentiation capacities. These cancer stem cells are supposed to be critical for tumor expansion and metastasis, tumor relapse and resistance to conventional therapies, such as chemo- and radiotherapy. The acquisition of these abilities has been attributed to the activation of alternative pathways, for instance, WNT, NOTCH, SHH, PI3K, Hippo, or NF-κB pathways, that regulate detoxification mechanisms; increase the metabolic rate; induce resistance to apoptotic, autophagic, and senescence pathways; promote the overexpression of drug transporter proteins; and activate specific stem cell transcription factors. The elimination of CSCs is an important goal in cancer therapeutic approaches because it could decrease relapses and metastatic dissemination, which are main causes of mortality in oncology patients. In this work, we discuss the role of these signaling pathways in CSCs along with their therapeutic potential.

Wnt/β-Catenin and Hippo Pathway Deregulation in Mammary Tumors of Humans, Dogs, and Cats

Mammary cancer is a common neoplasm in women, dogs, and cats that still represents a therapeutic challenge. Wnt/β-catenin and Hippo pathways are involved in tumor progression, cell differentiation, and metastasis. The aim of this study was to evaluate mRNA and protein expression of molecules involved in these pathways in human (HBC), canine (CMT), and feline mammary tumors (FMT). Real-time quantitative polymerase chain reaction (qPCR) for β-catenin, CCND1, YAP, TAZ, CTGF, and ANKRD1, western blotting for YAP, TAZ, and β-catenin, and immunohistochemistry for estrogen receptor (ER), progesterone receptor (PR), ERBB2, β-catenin, and YAP/TAZ were performed on mammary tumor tissues. The protein expression of active β-catenin was higher in tumors than in healthy tissues in all 3 species. The mRNA expression of the downstream gene CCND1 was increased in HBC ER⁺ and CMTs compared to healthy tissues. Membranous and cytoplasmic protein expression of β-catenin were strongly negatively correlated in all 3 species. Tumors showed an increased protein expression of YAP/TAZ when compared to healthy tissues. Notably, YAP/TAZ expression was higher in triple negative breast cancers when compared to HBC ER⁺ and in FMTs when compared to CMTs. The mRNA expression of β-catenin, YAP, TAZ, CTGF, and ANKRD1 was not different between tumors and healthy mammary gland in the 3 species. This study demonstrates deregulation of Wnt/β-catenin and Hippo pathways in mammary tumors, which was more evident at the protein rather than the mRNA level. Wnt/β-catenin and Hippo pathways seem to be involved in mammary carcinogenesis and therefore represent interesting therapeutic targets that should be further investigated.

The Hippo Pathway Effector YAP1 Regulates Intestinal Epithelial Cell Differentiation

The human intestine is covered by epithelium, which is continuously replaced by new cells provided by stem cells located at the bottom of the glands. The maintenance of intestinal stem cells is supported by a niche which is composed of several signaling proteins including the Hippo pathway effectors YAP1/TAZ. The role of YAP1/TAZ in cell proliferation and regeneration is well documented but their involvement on the differentiation of intestinal epithelial cells is unclear. In the present study, the role of YAP1/TAZ on the differentiation of intestinal epithelial cells was investigated using the HT29 cell line, the only multipotent intestinal cell line available, with a combination of knockdown approaches. The expression of intestinal differentiation cell markers was tested by qPCR, Western blot, indirect immunofluorescence and electron microscopy analyses. The results show that TAZ is not expressed while the abolition of YAP1 expression led to a sharp increase in goblet and absorptive cell differentiation and reduction of some stem cell markers. Further studies using double knockdown experiments revealed that most of these effects resulting from YAP1 abolition are mediated by CDX2, a key intestinal cell transcription factor. In conclusion, our results indicate that YAP1/TAZ negatively regulate the differentiation of intestinal epithelial cells through the inhibition of CDX2 expression.

[Emerging roles of Hippo signaling pathway in gastrointestinal cancers and its molecular mechanisms]

Hippo signaling pathway is highly conservative in evolution. MST1/2, LATS1/2, and the effector protein YAP/TAZ are the core members of this signaling pathway in mammalian cells. There have been many studies on YAP/TAZ and its downstream, however, the upstream regulatory factors of the Hippo signaling pathway remain unclear, and become one of the hot research directions of this pathway at present. In addition, Hippo signaling pathway can cross-talk with other signaling pathways such as Wnt and Notch signaling pathways, and plays an important role in controlling organ size, maintaining tissue homeostasis, and promoting tissue repair and regeneration. Abnormal Hippo signaling pathway may lead to the occurrence of a variety of tumors, especially gastrointestinal cancers such as liver cancer, colorectal cancer and gastric cancer. The abnormal expression of its members in gastrointestinal cancers is related to cancer cell proliferation, apoptosis, invasion and migration. Hippo signaling pathway is vital for liver repair and regeneration. Its inactivation will lead to the occurrence of primary liver cancer. The mechanism of YAP in liver cancer mainly depends on TEAD-mediated gene transcription. Hippo signaling pathway is also important for maintaining intestinal homeostasis, and its imbalance can lead to the occurrence and recurrence of colorectal cancer. In primary and metastatic gastric cancer, the expression of YAP/TAZ is significantly up-regulated, but the specific molecular mechanism is unclear. This article summarizes the recent progress on Hippo signaling pathway and its upstream regulatory factors, its roles in the development of gastrointestinal cancers and related molecular mechanisms; and also discusses the future research directions of Hippo signaling pathway.

Recent Advances of the Hippo/YAP Signaling Pathway in Brain Development and Glioma

The Hippo signaling pathway is highly conserved from Drosophila melanogaster to mammals and plays a crucial role in organ size control, tissue regeneration, and tumor suppression. The Yes-associated protein (YAP) is an important transcriptional co-activator that is negatively regulated by the Hippo signaling pathway. The Hippo signaling pathway is also regulated by various upstream regulators, such as cell polarity, adhesion proteins, and other signaling pathways (the Wnt/β-catenin, Notch, and MAPK pathways). Recently, accumulated evidence suggests that the Hippo/YAP signaling pathway plays important roles in central nervous system development and brain tumor, including glioma. In this review, we summarize the results of recent studies on the physiological effect of the Hippo/YAP signaling pathway in neural stem cells, neural progenitor cells, and glial cells. In particular, we also focus on the expression of MST1/2, LATS1/2, and the downstream effector YAP, in glioma, and offer a review of the latest research of the Hippo/YAP signaling pathway in glioma pathogenesis. Finally, we also present future research directions and potential therapeutic strategies for targeting the Hippo/YAP signaling in glioma.

The Hippo Tumor Suppressor Pathway (YAP/TAZ/TEAD/MST/LATS) and EGFR-RAS-RAF-MEK in cancer metastasis

Hippo Tumor Suppressor Pathway is the main pathway for cell growth that regulates tissue enlargement and organ size by limiting cell growth. This pathway is activated in response to cell cycle arrest signals (cell polarity, transduction, and DNA damage) and limited by growth factors or mitogens associated with EGF and LPA. The major pathway consists of the central kinase of Ste20 MAPK (Saccharomyces cerevisiae), Hpo (Drosophila melanogaster) or MST kinases (mammalian) that activates the mammalian AGC kinase dmWts or LATS effector (MST and LATS). YAP in the nucleus work as a cofactor for a wide range of transcription factors involved in proliferation (TEA domain family, TEAD1-4), stem cells (Oct4 mononuclear factor and SMAD-related TGFβ effector), differentiation (RUNX1), and Cell cycle/apoptosis control (p53, p63, and p73 family members). This is due to the diverse roles of YAP and may limit tumor progression and establishment. TEAD also coordinates various signal transduction pathways such as Hippo, WNT, TGFβ and EGFR, and effects on lack of regulation of TEAD cancerous genes, such as KRAS, BRAF, LKB1, NF2 and MYC, which play essential roles in tumor progression, metastasis, cancer metabolism, immunity, and drug resistance. However, RAS signaling is a pivotal factor in the inactivation of Hippo, which controls EGFR-RAS-RAF-MEK-ERK-mediated interaction of Hippo signaling. Thus, the loss of the Hippo pathway may have significant consequences on the targets of RAS-RAF mutations in cancer.

Impact of Taurine on the proliferation and apoptosis of human cervical carcinoma cells and its mechanism

BACKGROUND

Cervical cancer has the fourth highest incidence and mortality rate of all cancers in women worldwide; it seriously harms their physical and mental health. The aim of this study was to observe the roles and preliminary mechanism of Taurine (Tau)-induced apoptosis in cervical cancer cells.

METHODS

Cells from the human cervical cancer cell line SiHa were transfected with the recombinant plasmid pEGFP-N1-MST1 (mammalian sterile 20-like kinase 1); then, the cell proliferation activity was analyzed by the MTT assay, cell apoptosis by flow cytometry, and the related protein levels by Western blotting.

RESULTS

Tau inhibited the proliferation of SiHa cells and induced apoptosis in these cells (the apoptotic rate was 21.95% in the Tau 160 mmol/L group and 30% in the Tau 320 mmol/L group), upregulated the expression of the MST1 (control, 0.53; Tau 40-320 mmol/L groups, 0.84-1.45) and Bax (control, 0.45; Tau 40-320 mmol/L groups, 0.64-1.51) proteins (P < 0.01), and downregulated the expression of Bcl-2 (control, 1.28, Tau 40-320 mmol/L groups, 0.93-0.47) (P < 0.01). The overexpression of MST1 promoted the apoptosis of SiHa cells, enhanced the apoptosis-inductive effects of Tau (P < 0.01), upregulated the expression of the proapoptotic proteins p73, p53, PUMA (p53 upregulated modulator of apoptosis), and caspase-3, and promoted the phosphorylation of YAP (Yes-associated protein).

CONCLUSIONS

Tau inhibited the proliferation and induced the apoptosis of cervical cancer SiHa cells. The MST1 protein plays an important role in the Tau-induced apoptosis of cervical cancer cells.

HNF4α and CDX2 Regulate Intestinal YAP1 Promoter Activity

The Hippo pathway is important for tissue homeostasis, regulation of organ size and growth in most tissues. The co-transcription factor yes-associated protein 1 (YAP1) serves as a main downstream effector of the Hippo pathway and its dysregulation increases cancer development and blocks colonic tissue repair. Nevertheless, little is known about the transcriptional regulation of YAP1 in intestinal cells. The aim of this study to identify gene control regions in the YAP1 gene and transcription factors important for intestinal expression. Bioinformatic analysis of caudal type homeobox 2 (CDX2) and hepatocyte nuclear factor 4 alpha (HNF4α) chromatin immunoprecipitated DNA from differentiated Caco-2 cells revealed potential intragenic enhancers in the YAP1 gene. Transfection of luciferase-expressing YAP1 promoter-reporter constructs containing the potential enhancer regions validated one potent enhancer of the YAP1 promoter activity in Caco-2 and T84 cells. Two potential CDX2 and one HNF4α binding sites were identified in the enhancer by in silico transcription factor binding site analysis and protein-DNA binding was confirmed in vitro using electrophoretic mobility shift assay. It was found by chromatin immunoprecipitation experiments that CDX2 and HNF4α bind to the YAP1 enhancer in Caco-2 cells. These results reveal a previously unknown enhancer of the YAP1 promoter activity in the YAP1 gene, with importance for high expression levels in intestinal epithelial cells. Additionally, CDX2 and HNF4α binding are important for the YAP1 enhancer activity in intestinal epithelial cells.

Regulation of TEAD Transcription Factors in Cancer Biology

Transcriptional enhanced associate domain (TEAD) transcription factors play important roles during development, cell proliferation, regeneration, and tissue homeostasis. TEAD integrates with and coordinates various signal transduction pathways including Hippo, Wnt, transforming growth factor beta (TGFβ), and epidermal growth factor receptor (EGFR) pathways. TEAD deregulation affects well-established cancer genes such as KRAS, BRAF, LKB1, NF2, and MYC, and its transcriptional output plays an important role in tumor progression, metastasis, cancer metabolism, immunity, and drug resistance. To date, TEADs have been recognized to be key transcription factors of the Hippo pathway. Therefore, most studies are focused on the Hippo kinases and YAP/TAZ, whereas the Hippo-dependent and Hippo-independent regulators and regulations governing TEAD only emerged recently. Deregulation of the TEAD transcriptional output plays important roles in tumor progression and serves as a prognostic biomarker due to high correlation with clinicopathological parameters in human malignancies. In addition, discovering the molecular mechanisms of TEAD, such as post-translational modifications and nucleocytoplasmic shuttling, represents an important means of modulating TEAD transcriptional activity. Collectively, this review highlights the role of TEAD in multistep-tumorigenesis by interacting with upstream oncogenic signaling pathways and controlling downstream target genes, which provides unprecedented insight and rationale into developing TEAD-targeted anticancer therapeutics.

Analysis of the role of the Hippo pathway in cancer

Cancer is a serious health issue in the world due to a large body of cancer-related human deaths, and there is no current treatment available to efficiently treat the disease as the tumor is often diagnosed at a serious stage. Moreover, Cancer cells are often resistant to chemotherapy, radiotherapy, and molecular-targeted therapy. Upon further knowledge of mechanisms of tumorigenesis, aggressiveness, metastasis, and resistance to treatments, it is necessary to detect the disease at an earlier stage and for a better response to therapy. The hippo pathway possesses the unique capacity to lead to tumorigenesis. Mutations and altered expression of its core components (MST1/2, LATS1/2, YAP and TAZ) promote the migration, invasion, malignancy of cancer cells. The biological significance and deregulation of it have received a large body of interests in the past few years. Further understanding of hippo pathway will be responsible for cancer treatment. In this review, we try to discover the function of hippo pathway in different diversity of cancers, and discuss how Hippo pathway contributes to other cellular signaling pathways. Also, we try to describe how microRNAs, circRNAs, and ZNFs regulate hippo pathway in the process of cancer. It is necessary to find new therapy strategies for cancer.

New Therapeutic Approach for Targeting Hippo Signalling Pathway

Nuclear localization signals are short amino acid sequences that target proteins for nuclear import. In this manuscript, we have generated a chimeric tri-functional peptide composed of a cell penetrating peptide (CPP), a nuclear localization sequence and an interfering peptide blocking the interaction between TEAD and YAP, two transcription factors involved in the Hippo signalling pathway, whose deregulation is related to several types of cancer. We have validated the cell penetration and nuclear localization by flow cytometry and fluorescence microscopy and shown that the new generated peptide displays an apoptotic effect in tumor cell lines thanks to the specific nuclear delivery of the cargo, which targets a protein/protein interaction in the nucleus. In addition, the peptide has an anti-tumoral effect in vivo in xenograft models of breast cancer. The chimeric peptide designed in the current study shows encouraging prospects for developing nuclear anti- neoplastic drugs.

Roles of the MST1-JNK signaling pathway in apoptosis of colorectal cancer cells induced by Taurine

The aim of this study was to observe the impact of the mammalian sterile 20-like kinase 1-c-Jun N-terminal kinase (MST1-JNK) signaling pathway on apoptosis in colorectal cancer (CRC) cells induced by Taurine (Tau). Caco-2 and SW620 cells transfected with p-enhanced green fluorescent protein (EGFP)-MST1 or short interfering RNA (siRNA)-MST1 were treated with Tau for 48 h. Apoptosis was detected by flow cytometry, and the levels of MST1 and JNK were detected by western blotting. Compared with the control group, 80 mM Tau could significantly induce apoptosis of CRC cells, and the apoptotic rate increased with increasing Tau concentration (P < 0.01). Meanwhile, the protein levels of MST1 and phosphorylated (p)-JNK in Caco-2 cells increased significantly (P < 0.01). The apoptotic rate of the p-EGFP-MST1 plasmid-transfected cancer cells was significantly higher than that of the control group (P < 0.05); however, the apoptotic rate of the p-EGFP-MST1+Tau group was increased further (P < 0.01). Silencing the MST1 gene could decrease the apoptotic rate of cancer cells, and Tau treatment could reverse this decrease. Blocking the JNK signaling pathway significantly reduced the Tau-induced apoptotic rate of CRC cells. Thus, the MST1-JNK pathway plays an important role in Tau-induced apoptosis of CRC cells.

IFN-γ-response mediator GBP-1 represses human cell proliferation by inhibiting the Hippo signaling transcription factor TEAD

Interferon-gamma (IFN-γ) is a pleiotropic cytokine that exerts important functions in inflammation, infectious diseases, and cancer. The large GTPase human guanylate-binding protein 1 (GBP-1) is among the most strongly IFN-γ-induced cellular proteins. Previously, it has been shown that GBP-1 mediates manifold cellular responses to IFN-γ including the inhibition of proliferation, spreading, migration, and invasion and through this exerts anti-tumorigenic activity. However, the mechanisms of GBP-1 anti-tumorigenic activities remain poorly understood. Here, we elucidated the molecular mechanism of the human GBP-1-mediated suppression of proliferation by demonstrating for the first time a cross-talk between the anti-tumorigenic IFN-γ and Hippo pathways. The α9-helix of GBP-1 was found to be sufficient to inhibit proliferation. Protein-binding and molecular modeling studies revealed that the α9-helix binds to the DNA-binding domain of the Hippo signaling transcription factor TEA domain protein (TEAD) mediated by the ³⁷⁶VDHLFQK³⁸² sequence at the N-terminus of the GBP-1-α9-helix. Mutation of this sequence resulted in abrogation of both TEAD interaction and suppression of proliferation. Further on, the interaction caused inhibition of TEAD transcriptional activity associated with the down-regulation of TEAD-target genes. In agreement with these results, IFN-γ treatment of the cells also impaired TEAD activity, and this effect was abrogated by siRNA-mediated inhibition of GBP-1 expression. Altogether, this demonstrated that the α9-helix is the proliferation inhibitory domain of GBP-1, which acts independent of the GTPase activity through the inhibition of the Hippo transcription factor TEAD in mediating the anti-proliferative cell response to IFN-γ.

Colorectal carcinogenesis: Insights into the cell death and signal transduction pathways: A review

Colorectal carcinogenesis (CRC) imposes a major health burden in developing countries. It is the third major cause of cancer deaths. Despite several treatment strategies, novel drugs are warranted to reduce the severity of this disease. Adenomatous polyps in the colon are the major culprits in CRC and found in 45% of cancers, especially in patients 60 years of age. Inflammatory polyps are currently gaining attention in CRC, and a growing body of evidence denotes the role of inflammation in CRC. Several experimental models are being employed to investigate CRC in animals, which include the APC^min/+ mouse model, Azoxymethane, Dimethyl hydrazine, and a combination of Dextran sodium sulphate and dimethyl hydrazine. During CRC progression, several signal transduction pathways are activated. Among the major signal transduction pathways are p53, Transforming growth factor beta, Wnt/β-catenin, Delta Notch, Hippo signalling, nuclear factor erythroid 2-related factor 2 and Kelch-like ECH-associated protein 1 pathways. These signalling pathways collaborate with cell death mechanisms, which include apoptosis, necroptosis and autophagy, to determine cell fate. Extensive research has been carried out in our laboratory to investigate these signal transduction and cell death mechanistic pathways in CRC. This review summarizes CRC pathogenesis and the related cell death and signal transduction pathways.

COL1A1: A potential therapeutic target for colorectal cancer expressing wild-type or mutant KRAS

Colorectal cancer (CRC) treatment primarily relies on chemotherapy along with surgery, radiotherapy and, more recently, targeted therapy at the late stages. However, chemotherapeutic drugs have high cytotoxicity, and the similarity between the effects of these drugs on cancerous and healthy cells limits their wider use in clinical settings. Targeted monoclonal antibody treatment may compensate for this deficiency. Epidermal growth factor receptor (EGFR)-targeted drugs have a positive effect on CRC with intact KRAS proto-oncogene GTPase (KRAS or KRAS^WT), but may be ineffective or harmful in patients with KRAS mutations (KRAS^MUT). Therefore, it is important to identify drug target genes that are uniformly effective with regards to KRAS^WT and KRAS^MUT CRC. The present study performed gene expression analysis, and identified 294 genes upregulated in KRAS^WT and KRAS^MUT CRC samples. Collagen type I α 1 (COL1A1) was identified as the hub gene through STRING and Cytoscape analyses. Consistent with results obtained from Oncomine, a cancer microarray database and web-based data-mining platform, it was demonstrated that the expression of COL1A1 was significantly upregulated in CRC tissues and cell lines regardless of KRAS status. Inhibition of COL1A1 in KRAS^WT and KRAS^MUT CRC cell lines significantly decreased cell proliferation and invasion. In addition, increased COL1A1 expression in CRC was significantly associated with serosal invasion, lymph metastases and hematogenous metastases. Taken together, the findings of the present study indicated that COL1A1 may serve as a candidate diagnostic biomarker and a promising therapeutic target for CRC.

Mst1 regulates colorectal cancer stress response via inhibiting Bnip3-related mitophagy by activation of JNK/p53 pathway

The Hippo-Mst1 pathway is associated with tumor development and progression. However, little evidence is available for its role in colorectal cancer (CRC) stress response via mitochondrial homeostasis. In this study, we conducted gain-of function assay about Mst1 in CRC via adenovirus transfection. Then, cellular viability and apoptosis were measured via MTT, TUNEL assay, and typan blue staining. Mitochondrial function was detected via JC1 staining, mPTP opening assay, and immunofluorescence of cyt-c. Mitophagy was observed via western blots and immunofluorescence. Cell migration and proliferation were evaluated via Transwell and BrdU assay. Western blots were used to analyze the signaling pathways with JNK inhibitors or p53 siRNA. We found that Mst1 was down-regulated in CRC. Overexpression of Mst1 induced CRC apoptosis and impaired cell proliferation and migration. Functional studies have illustrated that recovery of Mst1 could activate JNK pathway which upregulated the p53 expression. The latter repressed Bnip3 transcription and activity, leading to the mitophagy arrest. The defective mitophagy impaired mitochondrial homeostasis, evoked cellular oxidative stress, and initiated the mitochondrial apoptosis. Meanwhile, bad-structured mitophagy also hindered the cancer proliferation via CyclinD/E. Moreover, Mst1-suppressed mitophagy was associated with CRC migration inhibition via regulation of CXCR4/7 expression. Collectively, our data described the comprehensive role of Mst1 in colorectal cancer stress response involving apoptosis, mobilization, and growth via handling mitophagy by JNK/p53/Bnip3 pathways.

Tumour YAP1 and PTEN expression correlates with tumour-associated myeloid suppressor cell expansion and reduced survival in colorectal cancer

The expansion of myeloid-derived suppressor cells (MDSCs) correlates with tumorigenesis in colorectal cancer (CRC). Here, we found a significant association between CD33⁺ MDSC number and Yes-associated protein 1 (YAP1) and phosphatase and tensin homologue (PTEN) levels in CRC patients (P < 0·05). Moreover, the CD33⁺ MDSCs, YAP1 and PTEN were identified as predictors for the prognosis of CRC patients (P < 0·05). Notably, CD33⁺ MDSCs were an independent survival predictor for CRC patients through a Cox model analysis. In vitro data determined that the expression levels of YAP1 and PTEN in CRC-derived cell lines were associated with CRC-derived MDSC induction, and the blockade of YAP1 and PTEN decreased CRC-derived MDSC induction. A mechanistic analysis revealed that YAP1 promoted CRC-derived MDSC induction by suppressing PTEN expression to up-regulate COX-2, P-AKT and P-p65 in CRC-derived cells, leading to secretion of the cytokine granulocyte-macrophage colony-stimulating factor. Our findings establish a novel mechanism of pro-tumorigenic MDSC induction mediated by ectopic YAP1 and PTEN expression in CRC.