TAZ expression as a prognostic indicator in colorectal cancer

A Hybrid Energy-Based and AI-Based Screening Approach for the Discovery of Novel Inhibitors of AXL

AXL, part of the TAM receptor tyrosine kinase family, plays a significant role in the growth and survival of various tissues and tumors, making it a critical target for cancer therapy. This study introduces a novel high-throughput virtual screening (HTVS) methodology that merges an AI-enhanced graph neural network, PLANET, with a geometric deep learning algorithm, DeepDock. Using this approach, we identified potent AXL inhibitors from our database. Notably, compound 9, with an IC50 of 9.378 nM, showed excellent inhibitory activity, suggesting its potential as a candidate for further research. We also performed molecular dynamics simulations to explore the interactions between compound 9 and AXL, providing insights for future enhancements. This hybrid screening method proves effective in finding promising AXL inhibitors, and advancing the development of new cancer therapies.

New Horizons in Cancer Progression and Metastasis: Hippo Signaling Pathway

The Hippo pathway is highly evolved to maintain tissue homeostasis in diverse species by regulating cell proliferation, differentiation, and apoptosis. In tumor biology, the Hippo pathway is a prime example of signaling molecules involved in cancer progression and metastasis. Hippo core elements LATS1, LATS2, MST1, YAP, and TAZ have critical roles in the maintenance of traditional tissue architecture and cell homeostasis. However, in cancer development, dysregulation of Hippo signaling results in tumor progression and the formation secondary cancers. Hippo components not only transmit biochemical signals but also act as mediators of mechanotransduction pathways during malignant neoplasm development and metastatic disease. This review confers knowledge of Hippo pathway core components and their role in cancer progression and metastasis and highlights the clinical role of Hippo pathway in cancer treatment. The Hippo signaling pathway and its unresolved mechanisms hold great promise as potential therapeutic targets in the emerging field of metastatic cancer research.

Regulation of Tumor Microenvironment through YAP/TAZ under Tumor Hypoxia

In solid tumors such as hepatocellular carcinoma (HCC), hypoxia is one of the important mechanisms of cancer development that closely influences cancer development, survival, and metastasis. The development of treatments for cancer was temporarily revolutionized by immunotherapy but continues to be constrained by limited response rates and the resistance and high costs required for the development of new and innovative strategies. In particular, solid tumors, including HCC, a multi-vascular tumor type, are sensitive to hypoxia and generate many blood vessels for metastasis and development, making it difficult to treat HCC, not only with immunotherapy but also with drugs targeting blood vessels. Therefore, in order to develop a treatment strategy for hypoxic tumors, various mechanisms must be explored and analyzed to treat these impregnable solid tumors. To date, tumor growth mechanisms linked to hypoxia are known to be complex and coexist with various signal pathways, but recently, mechanisms related to the Hippo signal pathway are emerging. Interestingly, Hippo YAP/TAZ, which appear during early tumor and normal tumor growth, and YAP/TAZ, which appear during hypoxia, help tumor growth and proliferation in different directions. Peculiarly, YAP/TAZ, which have different phosphorylation directions in the hypoxic environment of tumors, are involved in cancer proliferation and metastasis in various carcinomas, including HCC. Analyzing the mechanisms that regulate the function and expression of YAP in addition to HIF in the complex hypoxic environment of tumors may lead to a variety of anti-cancer strategies and combining HIF and YAP/TAZ may develop the potential to change the landscape of cancer treatment.

Squalene epoxidase promotes the chemoresistance of colorectal cancer via (S)-2,3-epoxysqualene-activated NF-κB

BACKGROUND

While de novo cholesterol biosynthesis plays a crucial role in chemotherapy resistance of colorectal cancer (CRC), the underlying molecular mechanism remains poorly understood.

METHODS

We conducted cell proliferation assays on CRC cells with or without depletion of squalene epoxidase (SQLE), with or without 5-fluorouracil (5-FU) treatment. Additionally, a xenograft mouse model was utilized to explore the impact of SQLE on the chemosensitivity of CRC to 5-FU. RNA-sequencing analysis and immunoblotting analysis were performed to clarify the mechanism. We further explore the effect of SQLE depletion on the ubiquitin of NF-κB inhibitor alpha (IκBα) and (S)-2,3-epoxysqualene on the binding of IκBα to beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) by using immunoprecipitation assay. In addition, a cohort of 272 CRC patients were selected for our clinical analyses.

RESULTS

Mechanistically, (S)-2,3-epoxysqualene promotes IκBα degradation and subsequent NF-κB activation by enhancing the interaction between BTRC and IκBα. Activated NF-κB upregulates the expression of baculoviral IAP repeat containing 3 (BIRC3), sustains tumor cell survival after 5-FU treatment and promotes 5-FU resistance of CRC in vivo. Notably, the treatment of terbinafine, an inhibitor of SQLE commonly used as antifungal drug in clinic, enhances the sensitivity of CRC to 5-FU in vivo. Additionally, the expression of SQLE is associated with the prognosis of human CRC patients with 5-FU-based chemotherapy.

CONCLUSIONS

Thus, our finding not only demonstrates a new role of SQLE in chemoresistance of CRC, but also reveals a novel mechanism of (S)-2,3-epoxysqualene-dependent NF-κB activation, implicating the combined potential of terbinafine for 5-FU-based CRC treatment.

The role of the FSGS disease gene product and nuclear pore protein NUP205 in regulating nuclear localization and activity of transcriptional regulators YAP and TAZ

Mutations in genes encoding nuclear pore proteins (NUPs) lead to the development of steroid-resistant nephrotic syndrome and focal segmental glomerulosclerosis (FSGS). However, the precise molecular mechanisms by which NUP dysfunction contributes to podocyte injury preceding FSGS remain unclear. The tightly regulated activity of Yes-associated protein (YAP) and WW-domain-containing transcription regulator 1 (TAZ), the transcriptional effectors of the Hippo pathway, is crucial for podocytes and the maintenance of the glomerular filter. In this study, we investigate the impact of NUPs on the regulation of YAP/TAZ nuclear import and activity in podocytes. In unbiased interactome studies using quantitative label-free mass spectrometry, we identify the FSGS disease gene products NUP107, NUP133, NUP205, and Exportin-5 (XPO5) as components of YAP and TAZ protein complexes in podocytes. Moreover, we demonstrate that NUP205 is essential for YAP/TAZ nuclear import. Consistently, both the nuclear interaction of YAP/TAZ with TEA domain transcription factor 1 and their transcriptional activity were dependent on NUP205 expression. Additionally, we elucidate a regulatory feedback mechanism whereby YAP activity is modulated in response to TAZ-mediated NUP205 expression. In conclusion, this study establishes a connection between the FSGS disease protein NUP205 and the activity of the transcriptional regulators and Hippo effectors YAP and TAZ and it proposes a potential pathological role of YAP/TAZ dysregulation in podocytes of patients with pathogenic NUP205 variants.

Polygonum barbatum extract reduces colorectal cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition via YAP and β-catenin pathway regulation

Colorectal cancer (CRC) is the third most common cancer worldwide with novel therapeutic developmental challenges. Polygonum barbatum has anticancer potential, but its mechanism(s) are unclear. This study investigates the inhibitory effect of P. barbatum on human CRC cells. Polygonum barbatum extract (PBE) and quercetin standard HPLC fingerprints were determined using analytical RP-HPLC and evaluations were completed using the human colon cancer cell line HCT-116 (KRASG13D mutation) and HT-29 (BRAF mutation) cells. Post-PBE treatment, cell viability, colony formation, migration, invasion, and apoptosis, as well as changes in the whole-transcriptome of cells were analyzed. PBE significantly reduced CRC cell growth, migration, and invasion, and the genes responsible for extracellular matrix (ECM) organization, cell motility, and cell growth were suppressed by PBE. The differentially expressed genes revealed that PBE treatment exerted a significant effect on the ECM interaction and focal adhesion pathways. Epithelial-to-mesenchymal transition markers, N-cadherin, vimentin, SLUG, and SNAIL, were shown to be regulated by PBE. These effects were associated with blockade of the Yes-associated protein and the GSK3β/β-catenin axis. PBE exerts a significant inhibitory effect on CRC cells and may be applicable in clinical trials.

Potassium voltage‑gated channel subfamily E member 4 facilitates the malignant progression of colon cancer by enhancing EGF containing fibulin extracellular matrix protein 2 expression

Colon cancer is a highly invasive and metastatic cancer with a poor prognosis. The University of Alabama at Birmingham Cancer data analysis portal (UALCAN) database indicates that potassium voltage-gated channel subfamily E member 4 (KCNE4) is highly expressed in colon cancer tissues. UALCAN data also show that KCNE4 expression is positively associated with individual cancer stages and negatively associated with patient survival. Therefore, the aim of the current study was to elucidate the functional role of KCNE4 in the biological behaviors of colon cancer cells and to investigate the underlying molecular mechanism. The gene EGF containing fibulin extracellular matrix protein 2 (EFEMP2) was found to be positively correlated with KCNE4 in colon cancer based on analysis performed using the LinkedOmics database; notably, upregulated EFEMP2 expression has been reported to be closely associated with the malignant phenotypes of colon cancer cells. The differences in the expression levels of KCNE4 and EFEMP2 between human colon cancer and normal colonic mucosa cell lines were assessed via reverse transcription-quantitative PCR and western blot assays. In addition, the proliferation, migration and invasion of colon cancer cells were determined using Cell Counting kit-8, colony formation, would healing and Transwell assays, and a co-immunoprecipitation assay was performed to confirm the interaction between KCNE4 and EFEMP2. The results of the study demonstrated that KCNE4 and EFEMP2 are markedly upregulated in colon cancer cells. In addition, KCNE4 interacted with and bound to EFEMP2. The suppressive effects of KCNE4 knockdown on the proliferation, colony formation, migration and invasion of colon cancer cells were attenuated by EFEMP2 overexpression. On the basis of these findings, it may be concluded that KCNE4 acts as an oncogene in colon cancer via the promotion of EFEMP2 expression.

Tumor matrix stiffness provides fertile soil for cancer stem cells

Matrix stiffness is a mechanical characteristic of the extracellular matrix (ECM) that increases from the tumor core to the tumor periphery in a gradient pattern in a variety of solid tumors and can promote proliferation, invasion, metastasis, drug resistance, and recurrence. Cancer stem cells (CSCs) are a rare subpopulation of tumor cells with self-renewal, asymmetric cell division, and differentiation capabilities. CSCs are thought to be responsible for metastasis, tumor recurrence, chemotherapy resistance, and consequently poor clinical outcomes. Evidence suggests that matrix stiffness can activate receptors and mechanosensor/mechanoregulator proteins such as integrin, FAK, and YAP, modulating the characteristics of tumor cells as well as CSCs through different molecular signaling pathways. A deeper understanding of the effect of matrix stiffness on CSCs characteristics could lead to development of innovative cancer therapies. In this review, we discuss how the stiffness of the ECM is sensed by the cells and how the cells respond to this environmental change as well as the effect of matrix stiffness on CSCs characteristics and also the key malignant processes such as proliferation and EMT. Then, we specifically focus on how increased matrix stiffness affects CSCs in breast, lung, liver, pancreatic, and colorectal cancers. We also discuss how the molecules responsible for increased matrix stiffness and the signaling pathways activated by the enhanced stiffness can be manipulated as a therapeutic strategy for cancer.

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.

GPR35 antagonist CID-2745687 attenuates anchorage-independent cell growth by inhibiting YAP/TAZ activity in colorectal cancer cells

Background and purpose: GPR35, a member of the orphan G-protein-coupled receptor, was recently implicated in colorectal cancer (CRC). However, whether targeting GPR35 by antagonists can inhibit its pro-cancer role has yet to be answered. Experimental approach: We applied antagonist CID-2745687 (CID) in established GPR35 overexpressing and knock-down CRC cell lines to understand its anti-cell proliferation property and the underlying mechanism. Key results: Although GPR35 did not promote cell proliferation in 2D conditions, it promoted anchorage-independent growth in soft-agar, which was reduced by GPR35 knock-down and CID treatment. Furthermore, YAP/TAZ target genes were expressed relatively higher in GPR35 overexpressed cells and lower in GPR35 knock-down cells. YAP/TAZ activity is required for anchorage-independent growth of CRC cells. By detecting YAP/TAZ target genes, performing TEAD4 luciferase reporter assay, and examining YAP phosphorylation and TAZ protein expression level, we found YAP/TAZ activity is positively correlated to GPR35 expression level, which CID disrupted in GPR35 overexpressed cells, but not in GPR35 knock-down cells. Intriguingly, GPR35 agonists did not promote YAP/TAZ activity but ameliorated CID's inhibitory effect; GPR35-promoted YAP/TAZ activity was only partly attenuated by ROCK1/2 inhibitor. Conclusion and implications: GPR35 promoted YAP/TAZ activity partly through Rho-GTPase with its agonist-independent constitutive activity, and CID exhibited its inhibitory effect. GPR35 antagonists are promising anti-cancer agents that target hyperactivation and overexpression of YAP/TAZ in CRC.

Somatic mutations in FAT cadherin family members constitute an underrecognized subtype of colorectal adenocarcinoma with unique clinicopathologic features

BACKGROUND

The FAT cadherin family members (FAT1, FAT2, FAT3 and FAT4) are conserved tumor suppressors that are recurrently mutated in several types of human cancers, including colorectal carcinoma (CRC).

AIM

To characterize the clinicopathologic features of CRC patients with somatic mutations in FAT cadherin family members.

METHODS

We analyzed 526 CRC cases from The Cancer Genome Atlas PanCancer Atlas dataset. CRC samples were subclassified into 2 groups based on the presence or absence of somatic mutations in FAT1, FAT2, FAT3 and FAT4. Individual clinicopathological data were collected after digital slide review. Statistical analysis was performed using t tests and chi-square tests.

RESULTS

This CRC study cohort had frequent mutations in the FAT1 (10.5%), FAT2 (11.2%), FAT3 (15.4%) and FAT4 (23.4%) genes. Two hundred CRC patients (38.0%) harbored somatic mutations in one or more of the FAT family genes and were grouped into the FAT mutated CRC subtype. The FAT-mutated CRC subtype was more commonly located on the right side of the colon (51.0%) than in the rest of the cohort (30.1%, P < 0.001). It showed favorable clinicopathologic features, including a lower rate of positive lymph nodes (pN1-2: 33.5% vs 46.4%, P = 0.005), a lower rate of metastasis to another site or organ (pM1: 7.5% vs 16.3%, P = 0.006), and a trend toward an early tumor stage (pT1-2: 25.0% vs 18.7%, P = 0.093). FAT somatic mutations were significantly enriched in microsatellite instability CRC (28.0% vs 2.1%, P < 0.001). However, FAT somatic mutations in microsatellite stable CRC demonstrated similar clinicopathologic behaviors, as well as a trend of a better disease-free survival rate (hazard ratio = 0.539; 95% confidence interval: 0.301-0.967; log-rank P = 0.073).

CONCLUSION

FAT cadherin family genes are frequently mutated in CRC, and their mutation profile defines a subtype of CRC with favorable clinicopathologic characteristics.

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.

The Hippo Pathway Effector Transcriptional Co-activator With PDZ-Binding Motif Correlates With Clinical Prognosis and Immune Infiltration in Colorectal Cancer

The transcriptional co-activator with PDZ-binding motif (TAZ) is a downstream effector of the Hippo pathway. It has been identified as an oncogene in certain tumor types; however, the function and role of TAZ in colorectal cancer (CRC) has not been illustrated. Here, we aimed to analyze the expression and role of TAZ in CRC. In this study, we investigated the expression level of TAZ in 127 CRC and matched adjacent normal tissues by immunohistochemistry (IHC) and analyzed its correlation with clinicopathological characteristics in CRC. Moreover, we further analyzed the role of TAZ in the CRC-associated immunology using integrative bioinformatic analyses. The cBioPortal and WebGestalt database were used to analyze the co-expressed genes and related pathways of TAZ in CRC by gene ontology (GO) and KEGG enrichment analyses. Meanwhile, the correlations between TAZ and the infiltrating immune cells and gene markers were analyzed by TIMER database. Our study revealed that TAZ expression is higher in CRC tissues than in matched adjacent non-tumor tissues. In addition, CRC patients with higher TAZ expression demonstrated poor overall survival (OS) and recurrent-free survival rates as compared to CRC patients with lower expression of TAZ. Furthermore, the TAZ expression was identified to closely associate with the immune infiltration of CD4 + T, CD8 + T, and B cells. Taken together, our findings suggest that TAZ may serve as a promising prognostic biomarker and therapeutic target in CRC.

YAP and TAZ: Monocorial and bicorial transcriptional co-activators in human cancers

The transcriptional regulators YAP and TAZ are involved in numerous physiological processes including organ development, growth, immunity and tissue regeneration. YAP and TAZ dysregulation also contribute to tumorigenesis, thereby making them attractive cancer therapeutic targets. Arbitrarily, YAP and TAZ are often considered as a single protein, and are referred to as YAP/TAZ in most studies. However, increasing experimental evidences documented that YAP and TAZ perform both overlapping and distinct functions in several physiological and pathological processes. In addition to regulating distinct processes, YAP and TAZ are also regulated by distinct upstream cues. The aim of the review is to describe the distinct roles of YAP and TAZ focusing particularly on cancer. Therapeutic strategies targeting either YAP and TAZ proteins or only one of them should be carefully evaluated. Selective targeting of YAP or TAZ may in fact impair different pathways and determine diverse clinical outputs.

Liver Colonization by Colorectal Cancer Metastases Requires YAP-Controlled Plasticity at the Micrometastatic Stage

Micrometastases of colorectal cancer can remain dormant for years prior to the formation of actively growing, clinically detectable lesions (i.e., colonization). A better understanding of this step in the metastatic cascade could help improve metastasis prevention and treatment. Here we analyzed liver specimens of patients with colorectal cancer and monitored real-time metastasis formation in mouse livers using intravital microscopy to reveal that micrometastatic lesions are devoid of cancer stem cells (CSC). However, lesions that grow into overt metastases demonstrated appearance of de novo CSCs through cellular plasticity at a multicellular stage. Clonal outgrowth of patient-derived colorectal cancer organoids phenocopied the cellular and transcriptomic changes observed during in vivo metastasis formation. First, formation of mature CSCs occurred at a multicellular stage and promoted growth. Conversely, failure of immature CSCs to generate more differentiated cells arrested growth, implying that cellular heterogeneity is required for continuous growth. Second, early-stage YAP activity was required for the survival of organoid-forming cells. However, subsequent attenuation of early-stage YAP activity was essential to allow for the formation of cell type heterogeneity, while persistent YAP signaling locked micro-organoids in a cellularly homogenous and growth-stalled state. Analysis of metastasis formation in mouse livers using single-cell RNA sequencing confirmed the transient presence of early-stage YAP activity, followed by emergence of CSC and non-CSC phenotypes, irrespective of the initial phenotype of the metastatic cell of origin. Thus, establishment of cellular heterogeneity after an initial YAP-controlled outgrowth phase marks the transition to continuously growing macrometastases.

SIGNIFICANCE

Characterization of the cell type dynamics, composition, and transcriptome of early colorectal cancer liver metastases reveals that failure to establish cellular heterogeneity through YAP-controlled epithelial self-organization prohibits the outgrowth of micrometastases. See related commentary by LeBleu, p. 1870.

IGF2BP2 promotes the progression of colorectal cancer through a YAP-dependent mechanism

To explore the effect of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) on colorectal cancer (CRC) by recognizing the m6A modification of YAP mRNA thus activating ErbB2 expression. High expressions of IGF2BP2, YAP, and ErbB2 promoted the proliferation, migration and invasion of CRC cells and reduced their apoptosis. IGF2BP2 recognized the m6A on YAP mRNA and promoted the translation of mRNA. YAP regulated ErbB2 expression by promoting TEAD4 enrichment in ErbB2 promoter region. Therefore, IGF2BP2 promoted the expression of ErbB2 to enhance the proliferation, invasion and migration of CRC cells, to repress cell apoptosis, and to promote solid tumor formation in nude mice. IGF2BP2 activates the expression of ErbB2 by recognizing the m6A of YAP, thus affecting the cell cycle of CRC, inhibiting cell apoptosis, and promoting proliferation.

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.

Cholesterol Metabolic Reprogramming in Cancer and Its Pharmacological Modulation as Therapeutic Strategy

Cholesterol is a ubiquitous sterol with many biological functions, which are crucial for proper cellular signaling and physiology. Indeed, cholesterol is essential in maintaining membrane physical properties, while its metabolism is involved in bile acid production and steroid hormone biosynthesis. Additionally, isoprenoids metabolites of the mevalonate pathway support protein-prenylation and dolichol, ubiquinone and the heme a biosynthesis. Cancer cells rely on cholesterol to satisfy their increased nutrient demands and to support their uncontrolled growth, thus promoting tumor development and progression. Indeed, transformed cells reprogram cholesterol metabolism either by increasing its uptake and de novo biosynthesis, or deregulating the efflux. Alternatively, tumor can efficiently accumulate cholesterol into lipid droplets and deeply modify the activity of key cholesterol homeostasis regulators. In light of these considerations, altered pathways of cholesterol metabolism might represent intriguing pharmacological targets for the development of exploitable strategies in the context of cancer therapy. Thus, this work aims to discuss the emerging evidence of in vitro and in vivo studies, as well as clinical trials, on the role of cholesterol pathways in the treatment of cancer, starting from already available cholesterol-lowering drugs (statins or fibrates), and moving towards novel potential pharmacological inhibitors or selective target modulators.

Periostin Promotes Colorectal Tumorigenesis through Integrin-FAK-Src Pathway-Mediated YAP/TAZ Activation

Periostin is a multifunctional extracellular matrix protein involved in various inflammatory diseases and tumor metastasis; however, evidence regarding whether and how periostin actively contributes to inflammation-associated tumorigenesis remains elusive. Here, we demonstrate that periostin deficiency significantly inhibits the occurrence of colorectal cancer in azoxymethane/dextran sulfate sodium-treated mice and in Apc^Min/+ mice. Moreover, periostin deficiency attenuates the severity of colitis and reduces the proliferation of tumor cells. Mechanistically, stromal fibroblast-derived periostin activates FAK-Src kinases through integrin-mediated outside-in signaling, which results in the activation of YAP/TAZ and, subsequently, IL-6 expression in tumor cells. Conversely, IL-6 induces periostin expression in fibroblasts by activating STAT3, which ultimately facilitates colorectal tumor development. These findings provide the evidence that periostin promotes colorectal tumorigenesis, and identify periostin- and IL-6-mediated tumor-stroma interaction as a promising target for treating colitis-associated colorectal cancer.

Cyclin A2 maintains colon homeostasis and is a prognostic factor in colorectal cancer

To clarify the function of cyclin A2 in colon homeostasis and colorectal cancer (CRC), we generated mice deficient for cyclin A2 in colonic epithelial cells (CECs). Colons of these mice displayed architectural changes in the mucosa and signs of inflammation, as well as increased proliferation of CECs associated with the appearance of low- and high-grade dysplasias. The main initial events triggering those alterations in cyclin A2-deficient CECs appeared to be abnormal mitoses and DNA damage. Cyclin A2 deletion in CECs promoted the development of dysplasia and adenocarcinomas in a murine colitis-associated cancer model. We next explored the status of cyclin A2 expression in clinical CRC samples at the mRNA and protein levels and found higher expression in tumors of patients with stage 1 or 2 CRC compared with those of patients with stage 3 or 4 CRC. A meta-analysis of 11 transcriptome data sets comprising 2239 primary CRC tumors revealed different expression levels of CCNA2 (the mRNA coding for cyclin A2) among the CRC tumor subtypes, with the highest expression detected in consensus molecular subtype 1 (CMS1) and the lowest in CMS4 tumors. Moreover, we found high expression of CCNA2 to be a new, independent prognosis factor for CRC tumors.

The Hippo-YAP Signaling as Guardian in the Pool of Intestinal Stem Cells

Despite endogenous insults such as mechanical stress and danger signals derived from the microbiome, the intestine can maintain its homeostatic condition through continuous self-renewal of the crypt–villus axis. This extraordinarily rapid turnover of intestinal epithelium, known to be 3 to 5 days, can be achieved by dynamic regulation of intestinal stem cells (ISCs). The crypt base-located leucine-rich repeat-containing G-protein-coupled receptor 5-positive (Lgr5⁺) ISCs maintain intestinal integrity in the steady state. Under severe damage leading to the loss of conventional ISCs, quiescent stem cells and even differentiated cells can be reactivated into stem-cell-like cells with multi-potency and contribute to the reconstruction of the intestinal epithelium. This process requires fine-tuning of the various signaling pathways, including the Hippo–YAP system. In this review, we summarize recent advances in understanding the correlation between Hippo–YAP signaling and intestinal homeostasis, repair, and tumorigenesis, focusing specifically on ISC regulation.

YAP/TAZ Signalling in Colorectal Cancer: Lessons from Consensus Molecular Subtypes

Simple Summary

Colorectal cancer (CRC) is a heterogeneous disease that can be divided into 4 consensus molecular subtypes (CMS) according to molecular profiling. The CMS classification is now considered as a reference framework for understanding the heterogeneity of CRC and for the implementation of precision medicine. Although the contribution of YAP/TAZ signalling to CRC has been intensively studied, there is little information on its role within each CMS subtype. This article aims to provide an overview of our knowledge of YAP/TAZ in CRC through the lens of the CMS classification.

Abstract

Recent advance in the characterization of the heterogeneity of colorectal cancer has led to the definition of a consensus molecular classification within four CMS subgroups, each associated with specific molecular and clinical features. Investigating the signalling pathways that drive colorectal cancer progression in relation to the CMS classification may help design therapeutic strategies tailored for each CMS subtype. The two main effectors of the Hippo pathway YAP and its paralogue TAZ have been intensively scrutinized for their contribution to colon carcinogenesis. Here, we review the knowledge of YAP/TAZ implication in colorectal cancer from the perspective of the CMS framework. We identify gaps in our current understanding and delineate research avenues for future work.

High Squalene Epoxidase in Tumors Predicts Worse Survival in Patients With Hepatocellular Carcinoma: Integrated Bioinformatic Analysis on NAFLD and HCC

This study aimed to identify candidate biomarkers for predicting outcomes in nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). Using Gene Expression Omnibus and The Cancer Genome Atlas (TCGA) databases, we identified common upregulated differential expressed genes (DEGs) in patients with NAFLD/nonalcoholic steatohepatitis (NASH) and HCC and conducted survival analysis of these upregulated DEGs with HCC outcomes. Two common upregulated DEGs including squalene epoxidase (SQLE) and EPPK1 messenger RNA (mRNA) were significantly upregulated in NAFLD, NASH, and HCC tissues, both in GSE45436 (P < .001) and TCGA profile (P < .001). Both SQLE and EPPK1 mRNA were upregulated in 15.56% and 8.06% patients with HCC in TCGA profile. Overexpression of SQLE in tumors was significantly associated with worse overall survival (OS) and disease-free survival (DFS) in patients with HCC (log-rank P = .027 and log-rank P = .048, respectively), while no statistical significances of OS and DFS were found in EPPK1 groups (both log-rank P > .05). For validation, SQLE upregulation contributed to significantly worse OS in patients wih HCC using Kaplan-Meier plotter analysis (hazard ratio = 1.43, 95% confidence interval: 1.01-2.02, log-rank P = .043). In addition, high level of SQLE significantly associated with advanced neoplasm histologic grade, advanced AJCC stage, and α-fetoprotein elevation (P = .036, .045, and .029, respectively). Squalene epoxidase is associated with OS and DFS and serves as a novel prognostic biomarker for patients with HCC.

TAZ negatively regulates the novel tumor suppressor ANKRD52 and promotes PAK1 dephosphorylation in lung adenocarcinomas

Lung cancer is the leading cause of cancer death, and therefore the discovery of novel therapeutic targets is crucial. P21-activated kinase (PAK1) is an important oncogene involved in the signaling of actin cytoskeleton organization. Although PAK1 inhibition has been shown to suppress cancer progression, specific PAK1 inhibitors are not available due to the complex structure and insufficient understanding of this kinase. The Hippo signaling effector TAZ is known to be elevated in multiple human cancers and to promote cancer metastasis. This study aimed to explore the role of TAZ in regulating the tumor suppressor ankyrin repeat domain 52 (ANKRD52) and PAK1 activity. A negative correlation between TAZ and ANKRD52 was observed, with knockdown of TAZ leading to enhanced ANKRD52 promoter activity and increased mRNA levels. Moreover, reduced ANKRD52 levels were associated with late-stage lung cancer. Knockdowns of ANKRD52 resulted in elevated cell mobility, while forced ANKRD52 expression attenuated cell mobility. ANKRD52 is a subunit of the protein phosphatase 6 (PP6) holoenzyme. Mass spectrometry analysis revealed the interaction between PAK1 and the ANKRD52-PP6 complex. Knockdown of ANKRD52 or PP6c resulted in upregulated PAK1 phosphorylation. Our study demonstrates that the novel tumor suppressor protein ANKRD52 is transcriptionally inhibited by TAZ, regulating cell mobility through interactions with PP6c and dephosphorylation of PAK1.

Targeting TAM to Tame Pancreatic Cancer

Pancreatic cancer is expected to become the second leading cause of cancer-related death within the next few years. Current therapeutic strategies have limited effectiveness and therefore there is an urgency to develop novel effective therapies. The receptor tyrosine kinase subfamily TAM (Tyro3, Axl, MerTK) is directly implicated in the pathogenesis of the metastatic, chemoresistant, and immunosuppressive phenotype in pancreatic cancer. TAM inhibitors are promising investigational therapies for pancreatic cancer due to their potential to target multiple aspects of pancreatic cancer biology. Specifically, recent mechanistic investigations and therapeutic combinations in the preclinical setting suggest that TAM inhibition with chemotherapy, targeted therapy, and immunotherapy should be evaluated clinically.

A Division of Labor between YAP and TAZ in Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. The paralogous transcriptional cofactors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ, also called WWTR1), the main downstream effectors of the Hippo signal transduction pathway, are emerging as pivotal determinants of malignancy in lung cancer. Traditionally, studies have tended to consider YAP and TAZ as functionally redundant transcriptional cofactors with similar biological impact. However, there is growing evidence that each of them also possesses distinct attributes. Here we sought to systematically characterize the division of labor between YAP and TAZ in non-small cell lung cancer (NSCLC), the most common histological subtype of lung cancer. Representative NSCLC cell lines as well as patient-derived data showed that the two paralogs orchestrated nonoverlapping transcriptional programs in this cancer type. YAP preferentially regulated gene sets associated with cell division and cell-cycle progression, whereas TAZ preferentially regulated genes associated with extracellular matrix organization. Depletion of YAP resulted in growth arrest, whereas its overexpression promoted cell proliferation. Likewise, depletion of TAZ compromised cell migration, whereas its overexpression enhanced migration. The differential effects of YAP and TAZ on key cellular processes were also associated with differential response to anticancer therapies. Uncovering the different activities and downstream effects of YAP and TAZ may thus facilitate better stratification of patients with lung cancer for anticancer therapies. SIGNIFICANCE: Thease findings show that oncogenic paralogs YAP and TAZ have distinct roles in NSCLC and are associated with differential response to anticancer drugs, knowledge that may assist lung cancer therapy decisions.

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.

Tripartite motif containing 24 regulates cell proliferation in colorectal cancer through YAP signaling

The protein, tripartite motif containing 24 (TRIM24) is a member of the TRIM protein family, and acts as a critical co‐regulator of multiple nuclear receptors. TRIM24 is dysregulated in many cancers, including colorectal carcinoma. However, its biological functions and molecular mechanisms with respect to colorectal carcinoma are still largely unknown. In the current study, we found that TRIM24 promotes YAP signaling for driving cell proliferation in colorectal cancer. TRIM24 was significantly upregulated in colorectal carcinoma, and its expression was negatively correlated with the survival of patients. Depletion of TRIM24 impaired the ability of the cancer cells to proliferate and form colonies. Furthermore, this study also revealed the mechanism underlying the recruitment of TRIM24 by the DANCR/KAT6A complex, which is bound to acetylated lysine 23 of histone H3 (H3K23), resulting in binding to the YAP promoter and activation of YAP transcription that ultimately enhances the proliferation of colorectal cancer cells. Our results revealed a novel mechanism involving TRIM24‐YAP signaling for the regulation of colorectal cancer. We also identified TRIM24 as a potential therapeutic molecule for targeting colorectal cancer.

TAZ Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Cancer Stem Cell-Like Invasive and Tumorigenic Properties

Helicobacter pylori infection, the main risk factor for gastric cancer (GC), leads to an epithelial–mesenchymal transition (EMT) of gastric epithelium contributing to gastric cancer stem cell (CSC) emergence. The Hippo pathway effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ) control cancer initiation and progression in many cancers including GC. Here, we investigated the role of TAZ in the early steps of H. pylori-mediated gastric carcinogenesis. TAZ implication in EMT, invasion, and CSC-related tumorigenic properties were evaluated in three gastric epithelial cell lines infected by H. pylori. We showed that H. pylori infection increased TAZ nuclear expression and transcriptional enhancer TEA domain (TEAD) transcription factors transcriptional activity. Nuclear TAZ and zinc finger E-box-binding homeobox 1 (ZEB1) were co-overexpressed in cells harboring a mesenchymal phenotype in vitro, and in areas of regenerative hyperplasia in gastric mucosa of H. pylori-infected patients and experimentally infected mice, as well as at the invasive front of gastric carcinoma. TAZ silencing reduced ZEB1 expression and EMT phenotype, and strongly inhibited invasion and tumorsphere formation induced by H. pylori. In conclusion, TAZ activation in response to H. pylori infection contributes to H. pylori-induced EMT, invasion, and CSC-like tumorigenic properties. TAZ overexpression in H. pylori-induced pre-neoplastic lesions and in GC could therefore constitute a biomarker of early transformation in gastric carcinogenesis.

[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.

Expression and prognostic significance of YAP, TAZ, TEAD4 and p73 in human laryngeal cancer

OBJECTIVES

The Hippo signaling pathway plays a critical role in organ size control and tissue homeostasis and its perturbation is associated with tumorigenesis. YAP (Yes associated protein) and TAZ (transcriptional co-activator with PDZ- binding motif) are the major nuclear effectors of the Hippo pathway interacting with TEADs (TEA domain) and p73 transcriptional factors to regulate gene expression. Altered expression of the above proteins promotes tumor initiation, progression and metastasis in a variety of cancer types. This study addresses their expression and prognostic significance in human laryngeal carcinoma.

METHODS

Protein expression of YAP, TAZ, TEAD4 and p73 was examined by immunohistochemistry in 121 human laryngeal squamous cell carcinomas. Correlations with clinicopathological data and survival were evaluated.

RESULTS

All proteins were overexpressed in human laryngeal carcinomas compared to non-neoplastic adjacent epithelium. High expression of YAP, TAZ, TEAD4 and p73 correlated significantly with high grade, advanced stage, supraglottic location of tumor, nodal metastases and recurrence. Furthermore, high expression of all proteins was significantly associated with poor overall and disease- free survival. p73 expression proved to be an independent predictive factor of survival and YAP expression proved to be an independent predictive factor of disease recurrence.

CONCLUSIONS

Deregulation of the expression of the Hippo pathway proteins is implicated in human laryngeal carcinogenesis and YAP and p73 have prognostic significance in the outcome of the disease.

LINC01413/hnRNP-K/ZEB1 Axis Accelerates Cell Proliferation and EMT in Colorectal Cancer via Inducing YAP1/TAZ1 Translocation

Long non-coding RNAs (lncRNAs) are crucial molecules in tumorigenesis and tumor growth in various human cancers, including colorectal cancer (CRC). Studies have revealed that lncRNAs can regulate cellular processes in cancers by interacting with proteins, for example RNA-binding proteins (RBPs). In this study, we recognize a novel lncRNA called LINC01413 that is upregulated in CRC tissues through lncRNAs microarray. Subsequently, we confirmed that an elevated level of LINC01413 expression in CRC tissues was strongly correlated to clinicopathological features, such as tumor size, tumor stage, lymph node metastasis, and distant metastasis, and its association with poor overall survival was also revealed. Additionally, LINC01413 facilitates cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Also, silenced LINC01413 restrains tumor growth in vivo. Moreover, LINC01413 binds with hnRNP-K and induces YAP1 (yes-associated protein 1)/TAZ1 (tafazzin) nuclear translocation to regulate the expression of ZEB1 in CRC cells. Taken together, this research suggested LINC01413 as a positive regulator in CRC progression through the LINC01413/hnRNP-K/TAZ1/YAP1/ZEB1 axis, broadening a new view on CRC treatment.

Identification of key genes involved in the development and progression of early-onset colorectal cancer by co-expression network analysis

A number of studies have revealed that there is an increasing incidence of early-onset colorectal cancer (CRC) in young adults (before the age of 50 years) and a progressive decline in CRC among older patients, after the age of 50 years (late-onset CRC). However, the etiology of early-onset CRC is not fully understood. The aim of the present study was to identify key genes associated with the development of early-onset CRC through weighted gene co-expression network analysis (WGCNA). The GSE39582 dataset was downloaded from the Gene Expression Omnibus database, and the data profiles of tissues from patients diagnosed before the age of 50 years were selected. The top 10,000 genes with the highest variability were used to construct the WGCNA. Hub genes were identified from the modules associated with clinical traits using gene significance >0.2 and module membership >0.8 as the cut-off criteria. Gene Ontology and pathway analyses were subsequently performed on the hub genes and a protein-protein interaction network (PPI) was constructed. The diagnostic value of module hub genes with a degree score >5 in the PPI network was verified in samples from patients with CRC diagnosed before the age of 50 years obtained from The Cancer Genome Atlas. Eight co-expressed gene modules were identified in the WGCNA and two modules (blue and turquoise) were associated with the tumor-node-metastasis stage. A total of 140 module hub genes were identified and found to be enriched in 'mitochondrial large ribosomal subunit', 'structural constituent of ribosome', 'poly (A) RNA binding', 'collagen binding', 'protein ubiquitination' and 'ribosome pathway'. Twenty-six module hub genes were found to have a degree score >5 in the PPI network, seven of which [secreted protein acidic and cysteine rich (SPARC), decorin (DCN), fibrillin 1 (FBN1), WW domain containing transcription regulator 1 (WWTR1), transgelin (TAGLN), DEAD-box helicase 28 (DDX28) and cold shock domain containing C2 (CSDC2)], had good prognostic values for patients with early-onset CRC, but not late-onset CRC. Therefore, SPARC, DCN, FBN1, WWTR1, TAGLN, DDX28 and CSDC2 may contribute to the development of early-onset CRC and may serve as potential diagnostic biomarkers.

AXL receptor tyrosine kinase as a promising anti-cancer approach: functions, molecular mechanisms and clinical applications

Molecular targeted therapy for cancer has been a research hotspot for decades. AXL is a member of the TAM family with the high-affinity ligand growth arrest-specific protein 6 (GAS6). The Gas6/AXL signalling pathway is associated with tumour cell growth, metastasis, invasion, epithelial-mesenchymal transition (EMT), angiogenesis, drug resistance, immune regulation and stem cell maintenance. Different therapeutic agents targeting AXL have been developed, typically including small molecule inhibitors, monoclonal antibodies (mAbs), nucleotide aptamers, soluble receptors, and several natural compounds. In this review, we first provide a comprehensive discussion of the structure, function, regulation, and signalling pathways of AXL. Then, we highlight recent strategies for targeting AXL in the treatment of cancer.AXL-targeted drugs, either as single agents or in combination with conventional chemotherapy or other small molecule inhibitors, are likely to improve the survival of many patients. However, future investigations into AXL molecular signalling networks and robust predictive biomarkers are warranted to select patients who could receive clinical benefit and to avoid potential toxicities.

Transcriptome analysis reveals that cyclophosphamide induces premature ovarian failure by blocking cholesterol biosynthesis pathway

AIMS

The present study aimed to investigate the effects of cyclophosphamide (Cytoxan, CTX) on premature ovarian failure (POF) in mice and its regulatory mechanisms by transcriptome analysis.

MAIN METHODS

Female C57BL/6 mice were treated with a single intraperitoneal injection of 70 mg/kg CTX. Serum levels of estradiol (E₂) and follicle stimulating hormone (FSH) were measured by enzyme-linked immunosorbent assay (ELISA), and follicular structure differences were observed by hematoxylin and eosin (H&E) staining. The main mechanism of POF was investigated by RNA-seq data, protein-protein interaction (PPI) networks and qPCR analysis.

KEY FINDINGS

The serum levels of E₂ were significantly decreased and those of FSH were significantly increased compared to the control group. The ovarian weights of the mice in the CTX group were reduced, and abnormal follicular structures were also observed in the CTX group. The RNA-seq data show that the downregulated genes were related to the cholesterol biosynthesis pathway. The PPI network and qPCR analyses further confirm that the PPAR signaling pathway and the ovarian infertility genes were also involved in blocking the cholesterol biosynthesis pathway. The differences were statistically significant.

SIGNIFICANCE

Our results indicate that CTX may exert its anti-tumor effects by inactivating the cholesterol biosynthesis pathway, and simultaneously reducing the supply of estrogen precursor materials, ultimately leading to the occurrence of POF. Our data provided a preliminary theoretical basis for resolving the clinical toxicity and side effects of CTX.

Identification of novel Nrf2 target genes as prognostic biomarkers in colitis-associated colorectal cancer in Nrf2-deficient mice

AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of many cytoprotective genes, plays a protective role in carcinogenesis. Recent studies have identified a specific gene-expression signature regulated by the Nrf2 pathway in lung adenocarcinoma and head-and-neck squamous cell cancer. However, the roles of Nrf2 in the development of colitis-associated colorectal cancer (CACC) have not been well characterized. Nrf2 target genes as prognostic biomarkers in CACC remain to be explored. Thus, this work aimed to identify the molecular changes that occur during mouse CACC progression to facilitate the development of diagnostic and prognostic biomarkers.

MAIN METHODS

The CACC model was established using azoxymethane (AOM) with dextran sulfate sodium salt (DSS) in BALB/c mice for 3 weeks to induce colitis-associated adenoma (CAA, early stage) and for 9 weeks to induce colitis-associated carcinoma (CAC, late stage). Using RNA-sequencing and bioinformatics analyses we examined the mRNA expression profiles of 6 groups: wild-type control (WT-C), WT-CAA, WT-CAC, Nrf2 knockout control (Nrf2KO-C), Nrf2KO-CAA, and Nrf2KO-CAC.

KEY FINDINGS

In the AOM/DSS model of colitis-associated tumorigenesis, Nrf2^-/- mice showed a phenotype similar to WT mice, but with significantly more tumors and a much higher percentage of adenocarcinomas. We identified 47 novel Nrf2 genes via gene expression profiling of tumor samples. Survival analysis showed that 23 of these genes were biomarkers of a poor prognosis in colon cancer patients.

SIGNIFICANCE

Nrf2 target genes deserve exploration as prognostic and therapeutic targets for CRC.

Human Colorectal Cancer from the Perspective of Mouse Models

Colorectal cancer (CRC) is a heterogeneous disease that includes both hereditary and sporadic types of tumors. Tumor initiation and growth is driven by mutational or epigenetic changes that alter the function or expression of multiple genes. The genes predominantly encode components of various intracellular signaling cascades. In this review, we present mouse intestinal cancer models that include alterations in the Wnt, Hippo, p53, epidermal growth factor (EGF), and transforming growth factor β (TGFβ) pathways; models of impaired DNA mismatch repair and chemically induced tumorigenesis are included. Based on their molecular biology characteristics and mutational and epigenetic status, human colorectal carcinomas were divided into four so-called consensus molecular subtype (CMS) groups. It was shown subsequently that the CMS classification system could be applied to various cell lines derived from intestinal tumors and tumor-derived organoids. Although the CMS system facilitates characterization of human CRC, individual mouse models were not assigned to some of the CMS groups. Thus, we also indicate the possible assignment of described animal models to the CMS group. This might be helpful for selection of a suitable mouse strain to study a particular type of CRC.

The YAP1-NMU Axis Is Associated with Pancreatic Cancer Progression and Poor Outcome: Identification of a Novel Diagnostic Biomarker and Therapeutic Target

Yes-associated protein (YAP)-1 is highly upregulated in pancreatic cancer and associated with tumor progression. However, little is known about the role of YAP1 and related genes in pancreatic cancer. Here, we identified target genes regulated by YAP1 and explored their role in pancreatic cancer progression and the related clinical implications. Analysis of different pancreatic cancer databases showed that Neuromedin U (NMU) expression was positively correlated with YAP1 expression in the tumor group. The Cancer Genome Atlas data indicated that high YAP1 and NMU expression levels were associated with poor mean and overall survival. YAP1 overexpression induced NMU expression and transcription and promoted cell motility in vitro and tumor metastasis in vivo via upregulation of epithelial-mesenchymal transition (EMT), whereas specific inhibition of NMU in cells stably expressing YAP1 had the opposite effect in vitro and in vivo. To define this functional association, we identified a transcriptional enhanced associate domain (TEAD) binding site in the NMU promoter and demonstrated that YAP1-TEAD binding upstream of the NMU gene regulated its transcription. These results indicate that the identified positive correlation between YAP1 and NMU is a potential novel drug target and biomarker in metastatic pancreatic cancer.

MicroRNA-139 is a predictor of prostate cancer recurrence and inhibits growth and migration of prostate cancer cells through cell cycle arrest and targeting IGF1R and AXL

BACKGROUND

We previously identified a panel of five microRNAs (miRNAs) associated with biochemical recurrence and metastasis following prostatectomy from prostate cancer patients using next-generation sequencing-based whole miRNome sequencing and quantitative polymerase chain reaction-based validation analysis. In this study, we examined the mechanism of action of miR-139-5p, one of the downregulated miRNAs identified in the panel.

METHODS

Using a cohort of 585 patients treated with radical prostatectomy, we examined the prognostic significance of miR-139 (dichotomized around the median) using the Kaplan-Meier method and Cox proportional hazard models. We validated these results using The Cancer Genome Atlas (TCGA) data. We created cell lines that overexpressed miR-139 to confirm its targets as well as examine pathways through which miR-139 may function using cell-based assays.

RESULTS

Low miR-139 expression was significantly associated with a variety of prognostic factors in prostate cancer, including Gleason score, pathologic stage, margin positivity, and lymph node status. MiR-139 expression was associated with prognosis: the cumulative incidence of biochemical recurrence and metastasis were significantly lower among patients with high miR-139 expression (P = .0004 and .038, respectively). Validation in the TCGA data set showed a significant association between dichotomized miR-139 expression and biochemical recurrence (odds ratio, 0.52; 95% confidence interval, 0.33-0.82). Overexpression of miR-139 in prostate cancer cells led to a significant reduction in cell proliferation and migration compared with control cells, with cells arrested in G2 of cell cycle. IGF1R and AXL were identified as potential targets of miR-139 based on multiple miRNA-binding sites in 3'-untranslated regions of both the genes and their association with prostate cancer growth pathways. Luciferase assays verified AXL and IGF1R as direct targets of miR-139. Furthermore, immunoblotting of prostate cancer cells demonstrated IGF1R and AXL protein expression were inhibited by miR-139 treatment, which was reversed by the addition of miR-139 antagomir. Examination of the molecular mechanism of growth inhibition by miR-139 revealed the downregulation of activated AKT and cyclin D1, with upregulation of the CDK inhibitor p21.

CONCLUSIONS

miR-139 is associated with improved prognosis in patients with localized prostate cancer, which may be mediated through downregulation of IGF1R and/or AXL and associated signaling pathway components.

Jiedu Sangen Decoction Inhibits the Invasion and Metastasis of Colorectal Cancer Cells by Regulating EMT through the Hippo Signaling Pathway

Colorectal cancer (CRC) is one of the most common malignant tumors affecting the digestive tract. Moreover, the invasion and metastasis of CRC are the main reason therapy is usually inefficient. Decreased intercellular adhesion and enhanced cell motility induced by epithelial-mesenchymal transition (EMT) provide the basic conditions for the invasion and metastasis of the epithelial tumor cells of CRC. The Jiedu Sangen Decoction (JSD) is a prescription that has been used for more than 50 years in the treatment of CRC in the Zhejiang Hospital of Traditional Chinese Medicine. The aim of this study was to investigate the mechanism of JSD-triggered inhibition of invasion and metastasis in colon cancer. In vitro, the EMT model of the SW480 cells was induced by using epithelial growth factor (50 ng/mL). In vivo, the murine model of liver metastasis was constructed by inoculating mice with the SW480 cells. The effects of JSD on cell migration, invasion, and proliferation were determined using the transwell assay and CCK-8 assay. Moreover, the proteins related to the EMT process and the Hippo signaling pathway in the cancerous tissues and cell lines were determined by western blotting and immunostaining. JSD could significantly inhibit the proliferation, migration, and invasion of CRC cells and reverse their EMT status (all, P < 0.05). Moreover, after intervention with JSD, the levels of E-Cadherin (E-cad) increased, whereas the expression levels of N-Cadherin (N-cad), Yes-associated protein (YAP), and the transcriptional coactivator with the PDZ-binding motif (TAZ) decreased in both the SW480 cells and the tumor tissues. In summary, JSD reversed EMT and inhibited the invasion and metastasis of CRC cells through the Hippo signaling pathway.

miR-125a-5p inhibits colorectal cancer cell epithelial-mesenchymal transition, invasion and migration by targeting TAZ

Background: miR-125a-5p regulated biological processes in various types of cancer, including colorectal cancer (CRC). TAZ, a vital transcriptional coactivators of the Hippo pathway, was found to be overexpressed in various cancers.

Objectives: This study aims to study the effect of miR-125a-5p on the progression of CRC by regulating TAZ expression.

Methods: In this study, miR-125a-5p and TAZ expression in CRC tissue and cell lines were detected by real-time polymerase chain reaction (RT-PCR). Luciferase reporter assay was applied to detect whether TAZ was a target of miR-125a-5p. Cell migration and invasion were detected in vitro by wound-healing assay and cell invasion assay. Western blot was used to detect the expression of epithelial-mesenchymal transition (EMT)-related proteins.

Findings: The results revealed downregulation of miR-125a-5p, as well as upregulation of TAZ in CRC tissue and cell lines. TAZ was identified as a direct target of miR-125a-5p, and its expression was negatively regulated by miR-125a-5p in CRC cell lines. The functional studies revealed that overexpression of miR-125a-5p inhibited the migration, invasion and EMT of CRC cells, while upregulation of TAZ reversed the inhibitory effect caused by miR-125a-5p.

Conclusion: Our data suggest that miR-125a-5p inhibits CRC cell migration, invasion and EMT by targeting TAZ. These results suggest that miR-125a-5p serves as a potential therapeutic biomarker for CRC patients.

Harmine induces anticancer activity in breast cancer cells via targeting TAZ

Harmine (HM) is a β-carboline alkaloid found in multiple medicinal plants. It has been used in folk medicine for anticancer therapy; however, the molecular mechanism of HM on human breast cancer remains unclear. Transcriptional co-activator with PDZ-binding motif (TAZ), also known as WW domain-containing transcription regulator 1, serves an important role in the carcinogenesis and progression of breast cancer. The aim of the present study was to elucidate the potential anticancer activity and mechanism of HM in breast cancer, in vitro and in vivo. Cell proliferation was measured using a CCK-8 assay, apoptotic activity was detected by flow cytometry and DAPI staining, and cell migration was examined using a wound healing assay. The expression of proteins, including extracellular signal-regulate kinase (Erk), phosphorylated (p-) Erk, protein kinase B (Akt), p-Akt, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax), were determined by western blotting. The mRNA expression of TAZ was detected using reverse transcription-quantitative polymerase chain reaction analysis. The expression of proteins in mouse tumor tissues were examined by immunohistochemistry. HM significantly suppressed cellular proliferation and migration, promoted apoptosis in vitro and inhibited tumor growth in vivo. In addition, HM significantly decreased the expression of TAZ, p-Erk, p-Akt and Bcl-2, but increased that of Bax. The overexpression of TAZ in breast cancer cells inhibited the antitumor effect of HM. In conclusion, HM was found to induce apoptosis and prevent the proliferation and migration of human breast cancer cell lines, possibly via the downregulation of TAZ.

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.

TAZ sensitizes EGFR wild-type non-small-cell lung cancer to gefitinib by promoting amphiregulin transcription

Comparatively less toxic and more tolerated, epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are recommendable for advanced non-small-cell lung cancer (NSCLC) patients with EGFR-sensitive mutations. Some EGFR wild-type patients with specific biomarkers also show a response to the drug. TAZ is an oncogene closely associated with the therapeutic effect of EGFR-TKIs. However, this association remains to be clarified. This study aimed to clarify the mechanism through which TAZ sensitizes EGFR wild-type NSCLC to gefitinib. We used CCK-8 assays and in vivo experiments to investigate the influence of TAZ on gefitinib in EGFR wild-type NSCLC. To further validate the tumorigenic role of TAZ, we performed Human umbilical vein endothelial cell (HUVEC) tube formation and migration assays. Luciferase reporter assays, quantitative real-time PCR (qPCR), immunoblotting and Chromatin immunoprecipitation collaborated with qPCR illuminated the mechanism through which TAZ caused those phenotypes. The results showed TAZ promoted the angiogenesis of NSCLC cell lines and improved gefitinib sensitivity in EGFR wild-type NSCLC in vitro and in vivo. Luciferase reporter assays and ChIP-qPCR experiments showed TAZ upregulated AREG by promoting its transcription. EGFR signaling pathway was activated as TAZ was highly expressed. Rescue experiments were conducted to confirm the indispensable role of AREG in tumorigenesis and gefitinib sensitivity regulated by TAZ. Our study concluded that TAZ sensitized EGFR wild-type NSCLC to gefitinib through promoting amphiregulin transcription.

Squalene epoxidase promotes the proliferation and metastasis of lung squamous cell carcinoma cells though extracellular signal-regulated kinase signaling

Background

The biological function of squalene epoxidase (SQLE), an important rate‐limiting enzyme in downstream cholesterol synthesis, is to convert squalene to 2‐3 oxacin squalene. The expression of SQLE in lung cancer is abnormal. We conducted this study to investigate the effect of SQLE expression on lung squamous cell carcinoma (SCC) proliferation, migration, and invasion and its role in extracellular signal‐regulated kinase (ERK) signaling.

Methods

Cell Counting Kit 8, wound healing, and Transwell assays; Western blotting; and quantitative real‐time PCR were used to investigate the effect of SQLE in a lung SCC H520 cell line. Kaplan–Meier analysis was used to identify the prognostic significance of SQLE.

Results

Overexpression of SQLE promoted lung SCC cell proliferation, migration and invasion, whereas knockdown of SQLE expression showed the opposite effect. SQLE can interact with ERK to enhance its phosphorylation. SQLE may contribute to the pathogenesis of lung cancer by modulating ERK signaling. Further survival analysis indicated that high expression of SQLE indicated poor prognosis in lung SCC.

Conclusion

Our study presents novel evidence of potential biomarkers or therapeutic targets for lung SCC therapy and prognosis.

CALD1, CNN1, and TAGLN identified as potential prognostic molecular markers of bladder cancer by bioinformatics analysis

BACKGROUND

Bladder cancer (BC) is one of the most common malignant neoplasms in the genitourinary tract. We employed the GSE13507 data set from the Gene Expression Omnibus (GEO) database in order to identify key genes related to tumorigenesis, progression, and prognosis in BC patients.

METHODS

The data set used in this study included 10 normal bladder mucosae tissue samples and 165 primary BC tissue samples. Differentially expressed genes (DEGs) in the 2 types of samples were identified by GEO2R. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the online website DAVID. The online website STRING was used to construct a protein-protein interaction network. Moreover, the plugins in MCODE and cytoHubba in Cytoscape were employed to find the hub genes and modules in these DEGs.

RESULTS

We identified 154 DEGs comprising 135 downregulated genes and 19 upregulated genes. The GO enrichment results were mainly related to the contractile fiber part, extracellular region part, actin cytoskeleton, and extracellular region. The KEGG pathway enrichment results mainly comprised type I diabetes mellitus, asthma, systemic lupus erythematosus, and allograft rejection. A module was identified from the protein-protein interaction network. In total, 15 hub genes were selected and 3 of them comprising CALD1, CNN1, and TAGLN were associated with both overall survival and disease-free survival.

CONCLUSION

CALD1, CNN1, and TAGLN may be potential biomarkers for diagnosis as well as therapeutic targets in BC patients.