miR-375 is involved in Hippo pathway by targeting YAP1/TEAD4-CTGF axis in gastric carcinogenesis. Cell Death Dis. 2018;9:92. [PMID: 29367737 PMCID: PMC5833783 DOI: 10.1038/s41419-017-0134-0]

PAQR4 oncogene: a novel target for cancer therapy

Despite decades of basic and clinical research and trials of promising new therapies, cancer remains a major cause of morbidity and mortality due to the emergence of drug resistance to anticancer drugs. These resistance events have a very well-understood underlying mechanism, and their therapeutic relevance has long been recognized. Thus, drug resistance continues to be a major obstacle to providing cancer patients with the intended "cure". PAQR4 (Progestin and AdipoQ Receptor Family Member 4) gene is a recently identified novel protein-coding gene associated with various human cancers and acts through different signaling pathways. PAQR4 has a significant influence on multiple proteins that may regulate various gene expressions and may develop chemoresistance. This review discusses the roles of PAQR4 in tumor immunity, carcinogenesis, and chemoresistance. This paper is the first review, discussing PAQR4 in the pathogenesis of cancer. The review further explores the PAQR4 as a potential target in various malignancies.

Assessment of human embryonic stem cells differentiation into definitive endoderm lineage on the soft substrates

Pluripotent stem cells (PSCs) hold enormous potential for treating multiple diseases owing to their ability to self-renew and differentiate into any cell type. Albeit possessing such promising potential, controlling their differentiation into a desired cell type continues to be a challenge. Recent studies suggest that PSCs respond to different substrate stiffness and, therefore, can differentiate towards some lineages via Hippo pathway. Human PSCs can also differentiate and self-organize into functional cells, such as organoids. Traditionally, human PSCs are differentiated on stiff plastic or glass plates towards definitive endoderm and then into functional pancreatic progenitor cells in the presence of soluble growth factors. Thus, whether stiffness plays any role in differentiation towards definitive endoderm from human pluripotent stem cells (hPSCs) remains unclear. Our study found that the directed differentiation of human embryonic stem cells towards endodermal lineage on the varying stiffness did not differ from the differentiation on stiff plastic dishes. We also observed no statistical difference between the expression of yes-associated protein (YAP) and phosphorylated YAP. Furthermore, we demonstrate that lysophosphatidic acid, a YAP activator, enhanced definitive endoderm formation, whereas verteporfin, a YAP inhibitor, did not have the significant effect on the differentiation. In summary, our results suggest that human embryonic stem cells may not differentiate in response to changes in stiffness, and that such cues may not have as significant impact on the level of YAP. Our findings indicate that more research is needed to understand the direct relationship between biophysical forces and hPSCs differentiation.

TEAD4: A key regulator of tumor metastasis and chemoresistance - Mechanisms and therapeutic implications

Cancer metastasis is a complex process influenced by various factors, including epithelial-mesenchymal transition (EMT), tumor cell proliferation, tumor microenvironment, and cellular metabolic status, which remains a significant challenge in clinical oncology, accounting for a majority of cancer-related deaths. TEAD4, a key mediator of the Hippo signaling pathway, has been implicated in regulating these factors that are all critical in the metastatic cascade. TEAD4 drives tumor metastasis and chemoresistance, and its upregulation is associated with poor prognosis in many types of cancers, making it an attractive target for therapeutic intervention. TEAD4 promotes EMT by interacting with coactivators and activating the transcription of genes involved in mesenchymal cell characteristics and extracellular matrix remodeling. Additionally, TEAD4 enhances the stemness of cancer stem cells (CSCs) by regulating the expression of genes associated with CSC maintenance. TEAD4 contributes to metastasis by modulating the secretion of paracrine factors and promoting heterotypic cellular communication. In this paper, we highlight the central role of TEAD4 in cancer metastasis and chemoresistance and its impact on various aspects of tumor biology. Understanding the mechanistic basis of TEAD4-mediated processes can facilitate the development of targeted therapies and combination approaches to combat cancer metastasis and improve treatment outcomes.

YAP/TEAD-induced PRIM1 contributes to the progression and poor prognosis of gastric carcinoma

Gastric carcinoma has a poor prognosis and low survival rate. PRIM1 is closely associated with the origin of DNA replication and serves as a carcinogenic factor in multiple tumors. This study aimed to explore the functions of PRIM1 in the progression of gastric carcinoma. The luciferase reporter assay examined the regulatory effect of YAP1/TEAD4 on PRIM1. A xenograft tumor mouse model was constructed to observe cancer cell proliferation in vivo. The upregulation of PRIM1 was found in gastric carcinoma cells and tissues, and it was associated with poor prognosis. Silencing PRIM1 inhibited cell proliferation, arrested the cell cycle, and upregulated Cdc25, Cyclin B, and Cdc2 expression. In addition, apoptosis was increased upon PRIM1 knockdown, accompanied by increased protein levels of cleaved caspase-3 and caspase-8. In vivo, knockdown of PRIM1 suppressed the growth of xenograft tumors formed by gastric carcinoma cells. Moreover, PRIM1 silencing elevated the chemosensitivity of gastric carcinoma cells. By investigating molecular events downstream of the Hippo signaling pathway, we found that PRIM1 was a target gene of the YAP1/TEAD4 transcriptional regulatory complex. PRIM1 represents a novel target for gastric carcinoma therapeutic approaches.

Circular RNA hsa_circ_0051246 acts as a microRNA-375 sponge to promote the progression of gastric cancer stem cells via YAP1

Background

Gastric cancer (GC) stem cells play an important role in GC progression. Circular RNAs (circRNAs) act as microRNA (miRNA) sponges and inhibit the biological function of miRNAs in GC cytoplasm. MiRNAs also participate in GC progress. circ_0051246 was shown to be associated with miR-375 after analyzing GC microarray data GSE78091 and GSE83521. The oncoprotein Yes-associated protein 1 (YAP1) is targeted by miR-375 and can be inactivated via the Hippo tumor suppressor pathway. Due to insufficient research on circ_0051246, this study aimed to investigate its relationship with miR-375 and YAP1 in cancer stem cells (CSCs).

Methods

SGC-7901 CSCs were used to establish knockdown/overexpression models of circ_0051246, miR-375, and YAP1. Malignant phenotypes of CSCs were assessed using Cell Counting Kit 8, colony/sphere formation, 5-Ethynyl-2'-deoxyuridine assay, flow cytometry, Transwell, and wound healing assays. To detect the interactions between circ_0051246, miR-375, and YAP1 in CSCs, a dual-luciferase reporter assay and fluorescence in situ hybridization were performed. In addition, 24 BALB/c nude mice were used to establish orthotopic xenograft tumor models. Four groups of mice were injected with CSCs (1 × 106 cells/100 µL) with circ_0051246 knockdown, miR-375 overexpression, or their respective control cells, and tumor progression and gene expression were observed by hematoxylin-eosin staining, immunohistochemistry. Western blot and quantitative real-time PCR were utilized to examine protein and gene expression, respectively.

Results

Circ_0051246 silencing reduced viability, promoted apoptosis, and inhibited proliferation, migration and invasion of CSCs. The functional effects of miR-375 mimics were comparable to those of circ_0051246 knockdown; however, the opposite was observed after miR-375 inhibitors treatment of CSCs. Furthermore, circ_0051246-overexpression antagonized the miR-375 mimics' effects on CSCs. Additionally, YAP1 overexpression promoted CSC features, such as self-renewal, migration, and invasion, inhibited apoptosis and E-cadherin levels, and upregulated the expression of N-cadherin, vimentin, YAP1, neurogenic locus notch homolog protein 1, and jagged canonical notch ligand 1. Conversely, YAP1-silenced produced the opposite effect. Moreover, miR-375 treatment antagonized the malignant effects of YAP1 overexpression in CSCs. Importantly, circ_0051246 knockdown and miR-375 activation suppressed CSC tumorigenicity in vivo.

Conclusion

This study highlights the promotion of circ_0051246-miR-375-YAP1 axis activation in GC progression and provides a scientific basis for research on the molecular mechanism of CSCs.

Mutant p53 murine oviductal epithelial cells induce progression of high-grade serous carcinoma and are most sensitive to simvastatin therapy in vitro and in vivo

High-grade serous carcinoma (HGSC) is the most common and aggressive subtype of epithelial ovarian cancer, characterized by gain-of-function TP53 mutations originating in the fallopian tube epithelium. Therapeutic intervention occurs at advanced metastatic disease, due to challenges in early-stage diagnosis, with common disease recurrence and therapy resistance despite initial therapy success. The mevalonate pathway is exploited by many cancers and is potently inhibited by statin drugs. Statins have shown anti-cancer activity in many, but not all cancers. Here, we investigated the role of p53 status in relation to mevalonate pathway signaling in murine oviductal epithelial (OVE) cells and identified OVE cell sensitivity to statin inhibition. We found that p53R175H mutant and Trp53 knockout OVE cells have increased mevalonate pathway signaling compared to p53 wild-type OVE cells. Through orthotopic implantation to replicate the fallopian tube origin of HGSC, p53R175H mutant cells upregulated the mevalonate pathway to drive progression to advanced-stage ovarian cancer, and simvastatin treatment abrogated this effect. Additionally, simvastatin was more efficacious at inhibiting cell metabolic activity in OVE cells than atorvastatin, rosuvastatin and pravastatin. In vitro, simvastatin demonstrated potent effects on cell proliferation, apoptosis, invasion and migration in OVE cells regardless of p53 status. In vivo, simvastatin induced ovarian cancer disease regression through decreased primary ovarian tumor weight and increased apoptosis. Simvastatin also significantly increased cytoplasmic localization of HMG-CoA reductase in ovarian tumors. Downstream of the mevalonate pathway, simvastatin had no effect on YAP or small GTPase activity. This study suggests that simvastatin can induce anti-tumor effects and could be an important inhibitor of ovarian cancer progression.

miR-584-5p Inhibits Osteosarcoma Progression by Targeting Connective Tissue Growth Factor

Background: miR-584-5p is a critical regulator in the progression of multiple cancers. However, its specific role and downstream targets in osteosarcoma are unclear. This research investigated the roles and underlying mechanisms of miR-769-5p and the Hippo pathway in osteosarcoma cells. Materials and Methods: RT-qPCR, CCK-8 and EdU and colony formation, wound-healing and transwell chamber, flow cytometry, and Western blot assay detected the expression of miR-584-5p and CTGF, cell proliferation, migration, invasion apoptosis and protein expression. Result: Their study illuminated that miR-584-5p overexpression repressed osteosarcoma cell migration/invasion and proliferation and facilitated apoptosis. Mechanistically, miR-584-5p targets negatively regulated connective tissue growth factor (CTGF). miR-584-5p inhibited osteosarcoma cell metastasis by regulating CTGF. In addition, miR-584-5p inactivated the Hippo pathway through CTGF in osteosarcoma. Conclusion: miR-584-5p inhibits osteosarcoma cell proliferation, migration, and invasion and promotes apoptosis by targeting CTGF, indicating that miR-584-5p acts as a promising diagnostic and predictive biomarker for osteosarcoma.

H. pylori-induced NF-κB-PIEZO1-YAP1-CTGF axis drives gastric cancer progression and cancer-associated fibroblast-mediated tumour microenvironment remodelling

BACKGROUND

Gastric cancer (GC) is one of the most common tumours in East Asia countries and is associated with Helicobacter pylori infection. H. pylori utilizes virulence factors, CagA and VacA, to up-regulate pro-inflammatory cytokines and activate NF-κB signaling. Meanwhile, the PIEZO1 upregulation and cancer-associated fibroblast (CAF) enrichment were found in GC progression. However, the mechanisms of PIEZO1 upregulation and its involvement in GC progression have not been fully elucidated.

METHODS

The CAF enrichment and clinical significance were investigated in animal models and primary samples. The expression of NF-κB and PIEZO1 in GC was confirmed by immunohistochemistry staining, and expression correlation was analysed in multiple GC datasets. GSEA and Western blot analysis revealed the YAP1-CTGF axis regulation by PIEZO1. The stimulatory effects of CTGF on CAFs were validated by the co-culture system and animal studies. Patient-derived organoid and peritoneal dissemination models were employed to confirm the role of the PIEZO1-YAP1-CTGF cascade in GC.

RESULTS

Both CAF signature and PIEZO1 were positively correlated with H. pylori infection. PIEZO1, a mechanosensor, was confirmed as a direct downstream of NF-κB to promote the transformation from intestinal metaplasia to GC. Mechanistic studies revealed that PIEZO1 transduced the oncogenic signal from NF-κB into YAP1 signaling, a well-documented oncogenic pathway in GC progression. PIEZO1 expression was positively correlated with the YAP1 signature (CTGF, CYR61, and c-Myc, etc.) in primary samples. The secreted CTGF by cancer cells stimulated the CAF infiltration to form a stiffened collagen-enrichment microenvironment, thus activating PIEZO1 to form a positive feedback loop. Both PIEZO1 depletion by shRNA and CTGF inhibition by Procyanidin C1 enhanced the efficacy of 5-FU in suppressing the GC cell peritoneal metastasis.

CONCLUSION

This study elucidates a novel driving PIEZO1-YAP1-CTGF force, which opens a novel therapeutic avenue to block the transformation from precancerous lesions to GC. H. pylori-NF-κB activates the PIEZO1-YAP1-CTGF axis to remodel the GC microenvironment by promoting CAF infiltration. Targeting PIEZO1-YAP1-CTGF plus chemotherapy might serve as a potential therapeutic option to block GC progression and peritoneal metastasis.

Modulation of the hippo-YAP pathway by cyclic stretch in rat type 2 alveolar epithelial cells-a proof-of-concept study

Background: Mechanical ventilation (MV) is a life supporting therapy but may also cause lung damage. This phenomenon is known as ventilator-induced lung injury (VILI). A potential pathomechanisms of ventilator-induced lung injury may be the stretch-induced production and release of cytokines and pro-inflammatory molecules from the alveolar epithelium. Yes-associated protein (YAP) might be regulated by mechanical forces and involved in the inflammation cascade. However, its role in stretch-induced damage of alveolar cells remains poorly understood. In this study, we explored the role of YAP in the response of alveolar epithelial type II cells (AEC II) to elevated cyclic stretch in vitro. We hypothesize that Yes-associated protein activates its downstream targets and regulates the interleukin-6 (IL-6) expression in response to 30% cyclic stretch in AEC II. Methods: The rat lung L2 cell line was exposed to 30% cyclic equibiaxial stretch for 1 or 4 h. Non-stretched conditions served as controls. The cytoskeleton remodeling and cell junction integrity were evaluated by F-actin and Pan-cadherin immunofluorescence, respectively. The gene expression and protein levels of IL-6, Yes-associated protein, Cysteine-rich angiogenic inducer 61 (Cyr61/CCN1), and connective tissue growth factor (CTGF/CCN2) were studied by real-time polymerase chain reaction (RT-qPCR) and Western blot, respectively. Verteporfin (VP) was used to inhibit Yes-associated protein activation. The effects of 30% cyclic stretch were assessed by two-way ANOVA. Statistical significance as accepted at p < 0.05. Results: Cyclic stretch of 30% induced YAP nuclear accumulation, activated the transcription of Yes-associated protein downstream targets Cyr61/CCN1 and CTGF/CCN2 and elevated IL-6 expression in AEC II after 1 hour, compared to static control. VP (2 µM) inhibited Yes-associated protein activation in response to 30% cyclic stretch and reduced IL-6 protein levels. Conclusion: In rat lung L2 AEC II, 30% cyclic stretch activated YAP, and its downstream targets Cyr61/CCN1 and CTGF/CCN2 and proinflammatory IL-6 expression. Target activation was blocked by a Yes-associated protein inhibitor. This novel YAP-dependent pathway could be involved in stretch-induced damage of alveolar cells.

MicroRNAs: The key players regulating the crosstalk between Hippo and Wnt/β-catenin pathways in breast cancer

Breast Cancer has the highest burden in females worldwide and is predicted to increase by many folds with increasing lifestyle related risk factors, genetic mutations, and an aging population. The Hippo signalling and Wnt signalling pathways were identified as important signal transducers involved in maintaining organ development, tissue homeostasis, cell proliferation and apoptosis. microRNAs are short nucleotide sequences which act as regulatory components driving signal transductions in most cancers and can serve as both diagnostic and prognostic markers. Several reports have implicated that deregulated Hippo as well as Wnt signalling mediated by miRNAs together drive tumorigenesis, metastases and chemoresistance in breast cancer. Recent evidences on a crosstalk between Hippo and Wnt components elucidated how these pathways might be synchronized to have overlapping functions to promote tumorigenesis. Since miRNAs are demonstrated to target most of the components in both the pathways, in this review, we talk about the crosstalk between Hippo and Wnt signalling pathways and the potential microRNAs that might regulate the interplay between the two pathways in breast cancer, which has not been explored earlier.

MiR-375 promotes cisplatin sensitivity of lung adenocarcinoma

BACKGROUND

Cisplatin-based chemotherapy has been widely used in the treatment of lung adenocarcinoma (LUAD). However, the development of cisplatin resistance becomes a major obstacle impeding the curative effect. It remains necessary to uncover the molecular mechanism of cisplatin resistance.

METHODS

Based on the CCLE database, lung cancer cell lines were divided into cisplatin-resistant and cisplatin-sensitive groups. The differentially expressed miRNAs were filtered and further identified by survival prognosis analysis. After transfection with miR-375 inhibitor or mimic, cell cytotoxicity assay, flow cytometry and western blot were conducted to validate the role of miR-375. The transcription factor (TF)-miRNA network was constructed based on TransmiR. The target genes of miR-375 were predicted by Starbase and further verified by RT-qPCR and immunohistochemistry results in the Human Protein Atlas. Functional enrichment analysis was performed with GO terms and KEGG.

RESULTS

In this study, miR-375 showed the ability to promote cisplatin sensitivity and apoptosis of LUAD. Genes correlated with miR-375 in LUAD were analyzed and ABCC8 showed the strongest positive correlation. Moreover, transcription factors that regulate miR-375 expression were predicted. MBNL1, PTPN3, PRKD1 and RPN1 were identified as the target genes of miR-375. Enrichment analysis demonstrated that miR-375-related genes associated with promoting cell proliferation and anti-apoptosis were involved in the MAPK signaling pathway.

CONCLUSION

Overall, this study provides new insights into the role of miR-375 in the cisplatin sensitivity of LUAD. Our present findings may serve as a theoretical basis for new therapeutic strategies and predictive models of cisplatin resistance in LUAD.

Helicobacter pylori-induced aberrant demethylation and expression of GNB4 promotes gastric carcinogenesis via the Hippo-YAP1 pathway

BACKGROUND

Helicobacter pylori (H. pylori) infection causes aberrant DNA methylation and contributes to the risk of gastric cancer (GC). Guanine nucleotide-binding protein subunit beta-4 (GNB4) is involved in various tumorigenic processes. We found an aberrant methylation level of GNB4 in H. pylori-induced GC in our previous bioinformatic analysis; however, its expression and underlying molecular mechanisms are poorly understood.

METHODS

The expression, underlying signaling pathways, and clinical significance of GNB4 were analyzed in a local cohort of 107 patients with GC and several public databases. H. pylori infection was induced in in vitro and in vivo models. Methylation-specific PCR, pyrosequencing, and mass spectrometry analysis were used to detect changes in methylation levels. GNB4, TET1, and YAP1 were overexpressed or knocked down in GC cell lines. We performed gain- and loss-of-function experiments, including CCK-8, EdU, colony formation, transwell migration, and invasion assays. Nude mice were injected with genetically manipulated GC cells, and the growth of xenograft tumors and metastases was measured. Real-time quantitative PCR, western blotting, immunofluorescence, immunohistochemistry, chromatin immunoprecipitation, and co-immunoprecipitation experiments were performed to elucidate the underlying molecular mechanisms.

RESULTS

GNB4 expression was significantly upregulated in GC and correlated with aggressive clinical characteristics and poor prognosis. Increased levels of GNB4 were associated with shorter survival times. Infection with H. pylori strains 26695 and SS1 induced GNB4 mRNA and protein expression in GC cell lines and mice. Additionally, silencing of GNB4 blocked the pro-proliferative, metastatic, and invasive ability of H. pylori in GC cells. H. pylori infection remarkably decreased the methylation level of the GNB4 promoter region, particularly at the CpG#5 site (chr3:179451746-179451745). H. pylori infection upregulated TET1 expression via activation of the NF-κB. TET binds to the GNB4 promoter region which undergoes demethylation modification. Functionally, we identified that GNB4 induced oncogenic behaviors of tumors via the Hippo-YAP1 pathway in both in vitro and in vivo models.

CONCLUSIONS

Our findings demonstrate that H. pylori infection activates the NF-κB-TET1-GNB4 demethylation-YAP1 axis, which may be a potential therapeutic target for GC.

The Hippo signaling pathway in gastric cancer

Gastric cancer (GC) is an aggressive malignant disease which still lacks effective early diagnosis markers and targeted therapies, representing the fourth-leading cause of cancer-associated death worldwide. The Hippo signaling pathway plays crucial roles in organ size control and tissue homeostasis under physiological conditions, yet its aberrations have been closely associated with several hallmarks of cancer. The last decade witnessed a burst of investigations dissecting how Hippo dysregulation contributes to tumorigenesis, highlighting the therapeutic potential of targeting this pathway for tumor intervention. In this review, we systemically document studies on the Hippo pathway in the contexts of gastric tumor initiation, progression, metastasis, acquired drug resistance, and the emerging development of Hippo-targeting strategies. By summarizing major open questions in this field, we aim to inspire further in-depth understanding of Hippo signaling in GC development, as well as the translational implications of targeting Hippo for GC treatment.

PVT1 inhibition stimulates anti-tumor immunity, prevents metastasis, and depletes cancer stem cells in squamous cell carcinoma

Cancer stem cells (CSCs) cause tumor metastasis and immune evasion by as-yet-unknown molecular mechanisms. In the present study, we identify a long noncoding RNA (lncRNA), termed PVT1, which is highly expressed in CSCs and correlated closely with lymph node metastasis of head and neck squamous cell carcinoma (HNSCC). PVT1 inhibition eliminates CSCs, prevents metastasis, and stimulates anti-tumor immunity, while inhibiting HNSCC growth. Moreover, PVT1 inhibition promotes the infiltration of CD8⁺ T cells into the tumor microenvironment, thereby enhancing immunotherapy by PD1 blockade. Mechanistically, PVT1 inhibition stimulates the DNA damage response, which induces CD8⁺ T cell-recruiting chemokines, while preventing CSCs and metastasis via regulating the miR-375/YAP1 axis. In conclusion, targeting PVT1 might potentiate the elimination of CSCs via immune checkpoint blockade, prevent metastasis, and inhibit HNSCC growth.

Specific Overexpression of YAP in Vascular Smooth Muscle Attenuated Abdominal Aortic Aneurysm Formation by Activating Elastic Fiber Assembly via LTBP4

Abdominal aortic aneurysm (AAA) is a fatal vascular disease. Vascular smooth muscle cells (VSMCs) play a crucial role in the pathogenesis of AAA. Increasing evidence has shown that Yes-associated protein (YAP) is involved in diverse vascular diseases. However, the role of YAP in AAA remains unclear. The current study aimed to determine the role of YAP in AAA formation and the underlying mechanism. We found that YAP expression in VSMCs was markedly decreased in human and experimental AAA samples. Furthermore, VSMC-specific YAP overexpression prevented several pathogenic factor-induced AAA. Mechanistically, YAP overexpression in VSMCs promoted latent transforming growth factor-β binding protein 4 (LTBP4) expression, an important factor in elastic fiber assembly. Finally, silencing of LTBP4 in VSMCs abolished the protective role of YAP in AAA formation in vivo. Our results suggest that YAP promotes LTBP4-mediated elastic fibril assembly in VSMCs, which mitigates elastin degradation and AAA formation.

Cancer-associated fibroblasts potentiate colorectal cancer progression by crosstalk of the IGF2-IGF1R and Hippo-YAP1 signaling pathways

Colorectal cancer (CRC) is one of the most common cancers worldwide. The tumor microenvironment exerts crucial effects in driving CRC progression. Cancer-associated fibroblasts (CAFs) serve as one of the most important tumor microenvironment components promoting CRC progression. This study aimed to elucidate the novel molecular mechanisms of CAF-secreted insulin-like growth factor (IGF) 2 in colorectal carcinogenesis. Our results indicated that IGF2 was a prominent factor upregulated in CAFs compared with normal fibroblasts. CAF-derived conditioned media (CM) promoted tumor growth, migration, and invasion of HCT 116 and DLD-1 cells. IGF1R expression is significantly increased in CRC, serving as a potent receptor in response to IGF2 stimulation and predicting unfavorable outcomes for CRC patients. Apart from the PI3K-AKT pathway, RNA-seq analysis revealed that the YAP1-target signature serves as a prominent downstream effector to mediate the oncogenic signaling of IGF2-IGF1R. By single-cell RNA sequencing (scRNA-seq) and immunohistochemical validation, IGF2 was found to be predominantly secreted by CAFs, whereas IGF1R was expressed mainly by cancer cells. IGF2 triggers the nuclear accumulation of YAP1 and upregulates YAP1 target signatures; however, these effects were abolished by either IGF1R knockdown or inhibition with picropodophyllin (PPP), an IGF1R inhibitor. Using CRC organoid and in vivo studies, we found that cotargeting IGF1R and YAP1 with PPP and verteporfin (VP), a YAP1 inhibitor, enhanced antitumor effects compared with PPP treatment alone. In conclusion, this study revealed a novel molecular mechanism by which CAFs promote CRC progression. The findings highlight the translational potential of the IGF2-IGF1R-YAP1 axis as a prognostic biomarker and therapeutic target for CRC. © 2022 The Pathological Society of Great Britain and Ireland.

Regulatory enhancer profiling of mesenchymal-type gastric cancer reveals subtype-specific epigenomic landscapes and targetable vulnerabilities

OBJECTIVE

Gastric cancer (GC) comprises multiple molecular subtypes. Recent studies have highlighted mesenchymal-subtype GC (Mes-GC) as a clinically aggressive subtype with few treatment options. Combining multiple studies, we derived and applied a consensus Mes-GC classifier to define the Mes-GC enhancer landscape revealing disease vulnerabilities.

DESIGN

Transcriptomic profiles of ~1000 primary GCs and cell lines were analysed to derive a consensus Mes-GC classifier. Clinical and genomic associations were performed across >1200 patients with GC. Genome-wide epigenomic profiles (H3K27ac, H3K4me1 and assay for transposase-accessible chromatin with sequencing (ATAC-seq)) of 49 primary GCs and GC cell lines were generated to identify Mes-GC-specific enhancer landscapes. Upstream regulators and downstream targets of Mes-GC enhancers were interrogated using chromatin immunoprecipitation followed by sequencing (ChIP-seq), RNA sequencing, CRISPR/Cas9 editing, functional assays and pharmacological inhibition.

RESULTS

We identified and validated a 993-gene cancer-cell intrinsic Mes-GC classifier applicable to retrospective cohorts or prospective single samples. Multicohort analysis of Mes-GCs confirmed associations with poor patient survival, therapy resistance and few targetable genomic alterations. Analysis of enhancer profiles revealed a distinctive Mes-GC epigenomic landscape, with TEAD1 as a master regulator of Mes-GC enhancers and Mes-GCs exhibiting preferential sensitivity to TEAD1 pharmacological inhibition. Analysis of Mes-GC super-enhancers also highlighted NUAK1 kinase as a downstream target, with synergistic effects observed between NUAK1 inhibition and cisplatin treatment.

CONCLUSION

Our results establish a consensus Mes-GC classifier applicable to multiple transcriptomic scenarios. Mes-GCs exhibit a distinct epigenomic landscape, and TEAD1 inhibition and combinatorial NUAK1 inhibition/cisplatin may represent potential targetable options.

Hippo pathway dysregulation in gastric cancer: from Helicobacter pylori infection to tumor promotion and progression

The Hippo pathway plays a critical role for balancing proliferation and differentiation, thus regulating tissue homeostasis. The pathway acts through a kinase cascade whose final effectors are the Yes-associated protein (YAP) and its paralog transcriptional co‑activator with PDZ‑binding motif (TAZ). In response to a variety of upstream signals, YAP and TAZ activate a transcriptional program that modulates cellular proliferation, tissue repair after injury, stem cell fate decision, and cytoskeletal reorganization. Hippo pathway signaling is often dysregulated in gastric cancer and in Helicobacter pylori-induced infection, suggesting a putative role of its deregulation since the early stages of the disease. In this review, we summarize the architecture and regulation of the Hippo pathway and discuss how its dysregulation fuels the onset and progression of gastric cancer. In this setting, we also focus on the crosstalk between Hippo and other established oncogenic signaling pathways. Lastly, we provide insights into the therapeutic approaches targeting aberrant YAP/TAZ activation and discuss the related clinical perspectives and challenges.

Prolactin promotes crop epithelial proliferation of domestic pigeons (Columba livia) through the Hippo signaling pathway

The purpose of this study was to investigate whether prolactin (PRL) regulates the proliferation of pigeon crop epithelium through the Hippo signaling pathway during the breeding cycle. Twenty-four pairs of adult pigeons were allotted to four groups by different breeding stages, and their crops and serum were sampled. Eighteen pairs of young pigeons were selected and divided into three groups for the injection experiments. The results showed that the serum PRL content and crop epithelial thickness of pigeons increased significantly at day 17 of incubation (I17) and day 1 of chick-rearing (R1). In males, the mRNA levels of yes-associated transcriptional regulator (YAP) and snail family transcriptional repressor 2 (SNAI2) were peaked at I17, and the gene levels of large tumor suppressor kinase 1 (LATS1), serine/threonine kinase 3 (STK3), TEA domain transcription factor 3 (TEAD3), connective tissue growth factor (CTGF), MYC proto-oncogene (c-Myc) and SRY-box transcription factor 2 (SOX2) reached the maximum value at R1. In females, the gene expression of YAP, STK3, TEAD3, and SOX2 reached the greatest level at I17, the expression profile of SAV1, CTGF, and c-Myc were maximized at R1. In males, the protein levels of LATS1 and YAP were maximized at R1 and the CTGF expression was upregulated at I17. In females, LATS1, YAP, and CTGF reached a maximum value at I17, and the expression level of phosphorylated YAP was minimized at I17 in males and females. Subcutaneous injection of prolactin (injected for 6 d, 10 μg per kg body weight every day) on the left crop of pigeons can promote the proliferation of crop epithelium by increasing the CTGF level and reducing the phosphorylation level of YAP. YAP-TEAD inhibitor verteporfin (injection for 6 d, 2.5 mg per kg body weight every day) can inhibit the proliferation of crop epithelium induced by prolactin by inhibiting YAP and CTGF expression. In conclusion, PRL can participate in crop cell proliferation of pigeons by promoting the expression of YAP and CTGF in Hippo pathway.

Comprehensive microRNA analysis across genome-edited colorectal cancer organoid models reveals miR-24 as a candidate regulator of cell survival

Somatic mutations drive colorectal cancer (CRC) by disrupting gene regulatory mechanisms. Distinct combinations of mutations can result in unique changes to regulatory mechanisms leading to variability in the efficacy of therapeutics. MicroRNAs are important regulators of gene expression, and their activity can be altered by oncogenic mutations. However, it is unknown how distinct combinations of CRC-risk mutations differentially affect microRNAs. Here, using genetically-modified mouse intestinal organoid (enteroid) models, we identify 12 different modules of microRNA expression patterns across different combinations of mutations common in CRC. We also show that miR-24-3p is aberrantly upregulated in genetically-modified mouse enteroids irrespective of mutational context. Furthermore, we identify an enrichment of miR-24-3p predicted targets in downregulated gene lists from various mutational contexts compared to WT. In follow-up experiments, we demonstrate that miR-24-3p promotes CRC cell survival in multiple cell contexts. Our novel characterization of genotype-specific patterns of miRNA expression offer insight into the mechanisms that drive inter-tumor heterogeneity and highlight candidate microRNA therapeutic targets for the advancement of precision medicine for CRC.

YAP inhibits HCMV replication by impairing STING-mediated nuclear transport of the viral genome

YES-associated protein (YAP), a critical actor of the mammalian Hippo signaling pathway involved in diverse biological events, has gained increased recognition as a cellular factor regulated by viral infections, but very few studies have investigated their relationship vice versa. In this study, we show that YAP impairs HCMV replication as assessed by viral gene expression analysis and progeny assays, and that this inhibition occurs at the immediate-early stages of the viral life cycle, at the latest. Using YAP mutants lacking key functional domains and shRNA against TEAD, we show that the inhibitory effects of YAP on HCMV replication are nuclear localization- and TEAD cofactor-dependent. Quantitative real-time PCR (qPCR) and subcellular fractionation analyses reveal that YAP does not interfere with the viral entry process but inhibits transport of the HCMV genome into the nucleus. Most importantly, we show that the expression of stimulator of interferon genes (STING), recently identified as an important component for nuclear delivery of the herpesvirus genome, is severely downregulated by YAP at the level of gene transcription. The functional importance of STING is further confirmed by the observation that STING expression restores YAP-attenuated nuclear transport of the HCMV genome, viral gene expression, and progeny virus production. We also show that HCMV-upregulated YAP reduces expression of STING. Taken together, these findings indicate that YAP possesses both direct and indirect regulatory roles in HCMV replication at different infection stages.

Platr4 is an early embryonic lncRNA that exerts its function downstream on cardiogenic mesodermal lineage commitment

The mammalian genome encodes thousands of long non-coding RNAs (lncRNAs), many of which are developmentally regulated and differentially expressed across tissues, suggesting their potential roles in cellular differentiation. Despite this expression pattern, little is known about how lncRNAs influence lineage commitment at the molecular level. Here, we demonstrate that perturbation of an embryonic stem cell/early embryonic lncRNA, pluripotency-associated transcript 4 (Platr4), directly influences the specification of cardiac-mesoderm-lineage differentiation. We show that Platr4 acts as a molecular scaffold or chaperone interacting with the Hippo-signaling pathway molecules Yap and Tead4 to regulate the expression of a downstream target gene, Ctgf, which is crucial to the cardiac-lineage program. Importantly, Platr4 knockout mice exhibit myocardial atrophy and valve mucinous degeneration, which are both associated with reduced cardiac output and sudden heart failure. Together, our findings provide evidence that Platr4 is required in cardiac-lineage specification and adult heart function in mice.

Probiotics as multifaceted oral vaccines against colon cancer: A review

Probiotics are known as the live microorganisms that, upon adequate administration, elicit a health beneficial response inside the host. The probiotics are known as immunomodulators and exhibit anti-tumor properties. Advanced research has explored the potential use of probiotics as the oral vaccines without the latent risks of pathogenicity. Probiotic-based oral vaccines are known to induce mucosal immunity that prevents the host from several enteric infections. Probiotic bacteria have the ability to produce metabolites in the form of anti-inflammatory cytokines, which play an important role in the prevention of carcinogenesis and in the activation of the phagocytes that eliminate the preliminary stage cancer cells. This review discusses the advantages and disadvantages of using the oral probiotic vaccines as well as the mechanism of action of probiotics in colon cancer therapy. This review also employs the use of “PROBIO” database for selecting certain probiotics with immunomodulatory properties. Furthermore, the use of several probiotic bacteria as anti-colon cancer adjuvants has also been discussed in detail. Because the current studies and trials are more focused on using the attenuated pathogens instead of using the probiotic-based vaccines, future studies must involve the advanced research in exploiting the potential of several probiotic strains as adjuvants in cancer therapies.

Photonic crystal enhanced fluorescence emission and blinking suppression for single quantum dot digital resolution biosensing

While nanoscale quantum emitters are effective tags for measuring biomolecular interactions, their utilities for applications that demand single-unit observations are limited by the requirements for large numerical aperture (NA) objectives, fluorescence intermittency, and poor photon collection efficiency resulted from omnidirectional emission. Here, we report a nearly 3000-fold signal enhancement achieved through multiplicative effects of enhanced excitation, highly directional extraction, quantum efficiency improvement, and blinking suppression through a photonic crystal (PC) surface. The approach achieves single quantum dot (QD) sensitivity with high signal-to-noise ratio, even when using a low-NA lens and an inexpensive optical setup. The blinking suppression capability of the PC improves the QDs on-time from 15% to 85% ameliorating signal intermittency. We developed an assay for cancer-associated miRNA biomarkers with single-molecule resolution, single-base mutation selectivity, and 10-attomolar detection limit. Additionally, we observed differential surface motion trajectories of QDs when their surface attachment stringency is altered by changing a single base in a cancer-specific miRNA sequence.

Nanoscale emitters are useful for measuring biomolecular interactions, but are limited by weak signals. Here, the authors use a photonic crystal surface for 3000-fold signal enhancement, achieving single emitter sensitivity with extended on-time, and demonstrate its application in miRNA biomarker sensing.

MALAT1-miRNAs network regulate thymidylate synthase and affect 5FU-based chemotherapy

Background

The active metabolite of 5-Fluorouracil (5FU), used in the treatment of several types of cancer, acts by inhibiting the thymidylate synthase encoded by the TYMS gene, which catalyzes the rate-limiting step in DNA replication. The major failure of 5FU-based cancer therapy is the development of drug resistance. High levels of TYMS-encoded protein in cancerous tissues are predictive of poor response to 5FU treatment. Expression of TYMS is regulated by various mechanisms, including involving non-coding RNAs, both miRNAs and long non-coding RNAs (lncRNAs).

Aim

To delineate the miRNAs and lncRNAs network regulating the level of TYMS-encoded protein.

Main body

Several miRNAs targeting TYMS mRNA have been identified in colon cancers, the levels of which can be regulated to varying degrees by lncRNAs. Due to their regulation by the MALAT1 lncRNA, these miRNAs can be divided into three groups: (1) miR-197-3p, miR-203a-3p, miR-375-3p which are downregulated by MALAT1 as confirmed experimentally and the levels of these miRNAs are actually reduced in colon and gastric cancers; (2) miR-140-3p, miR-330-3p that could potentially interact with MALAT1, but not yet supported by experimental results; (3) miR-192-5p, miR-215-5p whose seed sequences do not recognize complementary response elements within MALAT1. Considering the putative MALAT1-miRNAs interaction network, attention is drawn to the potential positive feedback loop causing increased expression of MALAT1 in colon cancer and hepatocellular carcinoma, where YAP1 acts as a transcriptional co-factor which, by binding to the TCF4 transcription factor/ β-catenin complex, may increase the activation of the MALAT1 gene whereas the MALAT1 lncRNA can inhibit miR-375-3p which in turn targets YAP1 mRNA.

Conclusion

The network of non-coding RNAs may reduce the sensitivity of cancer cells to 5FU treatment by upregulating the level of thymidylate synthase.

Hsa-miR-143-3p inhibits Wnt-β-catenin and MAPK signaling in human corneal epithelial stem cells

Our previous study demonstrated hsa-miR-143-3p as one of the highly expressed miRNAs in enriched corneal epithelial stem cells (CESCs). Hence this study aims to elucidate the regulatory role of hsa-miR-143-3p in the maintenance of stemness in CESCs. The target genes of hsa-miR-143-3p were predicted and subjected to pathway analysis to select the targets for functional studies. Primary cultured limbal epithelial cells were transfected with hsa-miR-143-3p mimic, inhibitor or scrambled sequence using Lipofectamine 3000. The transfected cells were analysed for (i) colony forming potential, (ii) expression of stem cell (SC) markers/ transcription factors (ABCG2, NANOG, OCT4, KLF4, ΔNp63), (iii) differentiation marker (Cx43), (iv) predicted five targets of hsa-miR-143-3p (DVL3, MAPK1, MAPK14, KRAS and KAT6A), (v) MAPK signaling regulators and (vi) Wnt-β-catenin signaling regulators by qPCR, immunofluorescence staining and/or Western blotting. High expression of hsa-miR-143-3p increased the colony forming potential (10.04 ± 1.35%, p < 0.001) with the ability to form holoclone-like colonies in comparison to control (3.33 ± 0.71%). The mimic treated cells had increased expression of SC markers but reduced expression of Cx43 and hsa-miR-143-3p targets involved in Wnt-β-catenin and MAPK signaling pathways. The expression of β-catenin, active β-catenin and ERK2 in hsa-miR-143-3p inhibitor transfected cells were higher than the control cells and the localized nuclear expression indicated the activation of Wnt and MAPK signaling. Thus, the probable association of hsa-miR-143-3p in the maintenance of CESCs through inhibition of Wnt and MAPK signaling pathways was thus indicated.

Hippo in Gastric Cancer: From Signalling to Therapy

The Hippo pathway is one of the most important ones in mammals. Its key functions in cell proliferation, tissue growth, repair, and homeostasis make it the most crucial one to be controlled. Many means have been deployed for its regulation, since this pathway is not only composed of core regulatory components, but it also communicates with and regulates various other pathways, making this signalisation even more complex. Its role in cancer has been studied more and more over the past few years, and it presents YAP/TAZ as the major oncogenic actors. In this review, we relate how vital this pathway is for different organs, and how regulatory mechanisms have been bypassed to lead to cancerous states. Most studies present an upregulation status of YAP/TAZ, and urge the need to target them. A focus is made here on gastric carcinogenesis, its main dysregulations, and the major strategies adopted and tested to counteract Hippo pathway disbalance in this disease. Hippo pathway targeting can be achieved by various means, which are described in this review. Many studies have tested different potential molecules, which are detailed hereby. Though not all tested in gastric cancer, they could represent a real interest.

Non-coding RNAs in ferroptotic cancer cell death pathway: meet the new masters

Despite the recent advances in cancer therapy, cancer chemoresistance looms large along with radioresistance, a major challenge in dire need of thorough and minute investigation. Not long ago, cancer cells were reported to have proven refractory to the ferroptotic cell death, a newly discovered form of regulated cell death (RCD), conspicuous enough to draw attention from scholars in terms of targeting ferroptosis as a prospective therapeutic strategy. However, our knowledge concerning the underlying molecular mechanisms through which cancer cells gain immunity against ferroptosis is still in its infancy. Of late, the implication of non-coding RNAs (ncRNAs), including circular RNAs (circRNAs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs) in ferroptosis has been disclosed. Nevertheless, precisely explaining the molecular mechanisms behind the contribution of ncRNAs to cancer radio/chemotherapy resistance remains a challenge, requiring further clarification. In this review, we have presented the latest available information on the ways and means of regulating ferroptosis by ncRNAs. Moreover, we have provided important insights about targeting ncRNAs implicated in ferroptosis with the hope of opening up new horizons for overcoming cancer treatment modalities. Though a long path awaits until we make this ambitious dream come true, recent progress in gene therapy, including gene-editing technology will aid us to be optimistic that ncRNAs-based ferroptosis targeting would soon be on stream as a novel therapeutic strategy for treating cancer.

The E3 ubiquitin ligase, FBXW5, promotes the migration and invasion of gastric cancer through the dysregulation of the Hippo pathway

F-box and WD repeat domain-containing 5 (FBXW5), with WD40 repeats, can bind to the PPxY sequence of the large tumor suppressor kinases 1/2 (LATS1/2) kinase domain, resulting in ubiquitination. Ubiquitination and the subsequent degradation of LATS1/2 abrogate the Hippo pathway and worsen gastric cancer (GC). However, the effects and molecular mechanisms of FBXW5 in GC remain unexplored. To elucidate the clinical significance of FBXW5, immunohistochemistry was conducted to reveal the positive correlation between FBXW5 expression and lymph node metastasis (p < 0.001) and TNM stage (training cohort: p = 0.018; validation cohort: p = 0.001). Further, patients with high FBXW5 expression were found to have poor prognosis (training cohort: log-rank p = 0.020; validation cohort: log-rank p = 0.025). Cell experiments revealed the promoting effects of FBXW5 on the proliferation, invasion, metastasis, and chemoresistance of GC cells. Blocking LATS1-YAP1 leads to the loss of FBXW5-mediated regulation of the Hippo pathway and partial functions. Further, co-immunoprecipitation and in vivo ubiquitination assays revealed the interaction between FBXW5 and LATS1, which promoted the ubiquitination and degradation of LATS1. Based on mouse xenograft assays, FBXW5 silencing attenuated the growth of subcutaneous tumor xenografts. Altogether, FBXW5 was found to inactivate the Hippo signaling pathway by enhancing LATS1 ubiquitination and degradation, which promoted the invasion, metastasis, and drug resistance of GC cells.

Interaction of ncRNA and Epigenetic Modifications in Gastric Cancer: Focus on Histone Modification

Gastric cancer has developed as a very common gastrointestinal tumors, with recent effective advancements in the diagnosis and treatment of early gastric cancer. However, the prognosis for gastric cancer remains poor. As a result, there is in sore need of better understanding the mechanisms of gastric cancer development and progression to improve existing diagnostic and treatment options. In recent years, epigenetics has been recognized as an important contributor on tumor progression. Epigenetic changes in cancer include chromatin remodeling, DNA methylation and histone modifications. An increasing number of studies demonstrated that noncoding RNAs (ncRNAs) are associated with epigenetic changes in gastric cancer. Herein, we describe the molecular interactions of histone modifications and ncRNAs in epigenetics. We focus on ncRNA-mediated histone modifications of gene expression associated with tumorigenesis and progression in gastric cancer. This molecular mechanism will contribute to our deeper understanding of gastric carcinogenesis and progression, thus providing innovations in gastric cancer diagnosis and treatment strategies.

A Panel of Circulating microRNAs as a Potential Biomarker for the Early Detection of Gastric Cancer

Background

The high mortality rate of Gastric Cancer (GC) is a consequence of delayed diagnosis. The early diagnosis of GC could increase the five-year survival rate among patients. We aimed to find a panel of microRNAs (miRNA) for the detection of GC in the early stages.

Methods

In this case-control study, we selected consistently upregulated miRNAs from the results of 12 high-throughput miRNA profiling studies in GC. In the profiling phase, the differential expressions of 13 candidate miRNAs were analyzed by quantitative reverse-transcription PCR (qRT-PCR) in two pooled RNA samples prepared from the plasma of eight GC patients and eight matched controls. In the validation phase, significantly upregulated miRNAs from the profiling phase were further evaluated in the plasma samples of 97 patients with stage I-IV gastric adenocarcinoma and 100 healthy controls.

Results

In the profiling phase, six miRNAs (miR-18a, 21, 25, 92a, 125b and 221) were significantly upregulated in the GC patients compared to the controls (p<0.05). However, in the validation phase, only significant up-regulation of miR-18a, 21 and 125b was confirmed (p<0.05). A panel of miR-18a/21/125b was able to detect GC patients with stage I-IV from the controls (p<0.001; AUC=0.92, sensitivity=86%; specificity=85%). In addition, the panel could distinguish the early-stage GC (I+II) from the control group with an AUC of 0.83, a sensitivity of 83%, and a specificity of 75%.

Conclusion

A panel of circulating miR18a/21/125b could be suggested as a potential biomarker for the early detection of GC.

Long non-coding RNA LINC00649 regulates YES-associated protein 1 (YAP1)/Hippo pathway to accelerate gastric cancer (GC) progression via sequestering miR-16-5p

Although long non-coding RNA (LncRNA) LINC00649 is reported to be closely associated with acute myeloid leukemia (AML), prostate cancer and colorectal cancer, its role in regulating other types of cancer, such as gastric cancer (GC), has not been studied. This study analyzed the expression status of LINC00649 in GC tissues and cells by performing Real-Time qPCR analysis, and we found that LINC00649 tended to be enriched in cancerous tissues and cells but not in their normal counterparts, which were supported by the data from TCGA dataset. Next, by performing the gain- and loss-of-function experiments, we expectedly found that LINC00649 acted as an oncogene to accelerate GC cell proliferation, migration and epithelial-mesenchymal transition (EMT) in vitro and promote its tumorigenesis in vivo. Moreover, the online miRDB software predicted that miR-16-5p bound to both LINC00649 and 3' untranslated region (3'UTR) of YAP1 mRNA, which were validated by the following dual-luciferase reporter gene system assay and RNA pull-down assay. Finally, we proved that LINC00649 exerted its tumor-promoting effects in GC by regulating the miR-16-5p/YES-associated protein 1 (YAP1)/Hippo pathway. Mechanistically, knock-down of LINC00649 suppressed YAP1 expressions by releasing miR-16-5p, resulting in the recovery of the Hippo pathway, which suppressed the expression levels of the downstream oncogenes, including EGFR, SOX2 and OCT4, leading to the inhibition of the malignant phenotypes in GC cells. In conclusion, this study, for the first time, evidenced that LINC00649 promoted GC progression by targeting the miR-16-5p/YAP1/Hippo signaling pathway, which provided potential diagnostic and therapeutic indicators for GC treatment for clinical utilization.

LncRNA SFTA1P mediates positive feedback regulation of the Hippo-YAP/TAZ signaling pathway in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) regulate numerous biological processes involved in both development and carcinogenesis. Hippo-YAP/TAZ signaling, a critical pathway responsible for organ size control, is often dysregulated in a variety of cancers. However, the nature and function of YAP/TAZ-regulated lncRNAs during tumorigenesis remain largely unexplored. By profiling YAP/TAZ-regulated lncRNAs, we identified SFTA1P as a novel transcriptional target and a positive feedback regulator of YAP/TAZ signaling. Using non-small cell lung cancer (NSCLC) cell lines, we show that SFTA1P is transcriptionally activated by YAP/TAZ in a TEAD-dependent manner. Functionally, knockdown of SFTA1P in NSCLC cell lines inhibited proliferation, induced programmed cell death, and compromised their tumorigenic potential. Mechanistically, SFTA1P knockdown decreased TAZ protein abundance and consequently, the expression of YAP/TAZ transcriptional targets. We provide evidence that this phenomenon could potentially be mediated via its interaction with TAZ mRNA to regulate TAZ translation. Our results reveal SFTA1P as a positive feedback regulator of Hippo-YAP/TAZ signaling, which may serve as the molecular basis for lncRNA-based therapies against YAP/TAZ-driven cancers.

Non-Coding RNAs in Gastric Cancer: From Malignant Hallmarks to Clinical Applications

Gastric cancer (GC) is one of the most lethal malignancies worldwide. However, the molecular mechanisms underlying gastric carcinogenesis remain largely unknown. Over the past decades, advances in RNA-sequencing techniques have greatly facilitated the identification of various non-coding RNAs (ncRNAs) in cancer cells, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Accumulating evidence has revealed that ncRNAs are essential regulators in GC occurrence and development. However, ncRNAs represent an emerging field of cancer research, and their complex functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets in GC, further studies should focus on elucidating the intricate relationships between ncRNAs and GC, which can be translated into clinical practice. In this review, we summarize recent research progress on how ncRNAs modulate the malignant hallmarks of GC, especially in tumor immune escape, drug resistance, and stemness. We also discuss the promising applications of ncRNAs as diagnostic biomarkers and therapeutic targets in GC, aiming to validate their practical value for clinical treatment.

Deletion of pancreas-specific miR-216a reduces beta-cell mass and inhibits pancreatic cancer progression in mice

miRNAs have crucial functions in many biological processes and are candidate biomarkers of disease. Here, we show that miR-216a is a conserved, pancreas-specific miRNA with important roles in pancreatic islet and acinar cells. Deletion of miR-216a in mice leads to a reduction in islet size, β-cell mass, and insulin levels. Single-cell RNA sequencing reveals a subpopulation of β-cells with upregulated acinar cell markers under a high-fat diet. miR-216a is induced by TGF-β signaling, and inhibition of miR-216a increases apoptosis and decreases cell proliferation in pancreatic cells. Deletion of miR-216a in the pancreatic cancer-prone mouse line KrasG12D;Ptf1aCreER reduces the propensity of pancreatic cancer precursor lesions. Notably, circulating miR-216a levels are elevated in both mice and humans with pancreatic cancer. Collectively, our study gives insights into how β-cell mass and acinar cell growth are modulated by a pancreas-specific miRNA and also suggests miR-216a as a potential biomarker for diagnosis of pancreatic diseases.

miR-181a-2-3p Stimulates Gastric Cancer Progression via Targeting MYLK

Background: The abnormal expression of miRNAs facilitates tumorigenesis and development. miR-181a-2-3p is up-regulated in various cancers, yet its mechanism in gastric cancer (GC) remains elusive.

Objective: To understand mechanism of miR-181a-2-3p stimulating GC cell progression via targeting Myosin Light Chain Kinase (MYLK) expression.

Methods: Downstream genes of miRNA of interest were predicted in TargetScan and miRTarBase. qRT-PCR and western blot were applied to assess miR-181a-2-3p and MYLK expression in GC cells and normal cells. Dual-luciferase and RIP assays were completed to assess binding of miR-181a-2-3p and MYLK. Cell Counting Kit-8 (CCK-8) assay was conducted for detecting viability of AGS and SNU-1 cells, while Transwell tested migratory and invasive abilities of cells. Nude mouse transplantation tumor experiment was performed to assay tumor growth in vivo.

Results: miR-181a-2-3p was notably increased in human GC cell lines, while MYLK was remarkably down-regulated. RIP and dual-luciferase assay disclosed that miR-181a-2-3p targeted MYLK and repressed MYLK. Forced miR-181a-2-3p expression fostered GC cell proliferation, invasion, migration, and fostered tumor growth in vivo. Promoting effect of miR-181a-2-3p on GC cells was reversed when miR-181a-2-3p and MYLK were simultaneously overexpressed.

Conclusion: miR-181a-2-3p facilitated GC cell progression by targeting MYLK, and it may be a pivotal prognostic biomarker in investigating molecular mechanism of GC.

Identification of YAP1 as a novel downstream effector of the FGF2/STAT3 pathway in the pathogenesis of renal tubulointerstitial fibrosis

Chronic kidney disease is a global health problem and eventually develops into an end-stage renal disease (ESRD). It is now widely believed that renal tubulointerstitial fibrosis (TIF) plays an important role in the progression of ESRD. Renal tubular epithelial-mesenchymal transition (EMT) is an important cause of TIF. Studies have shown that FGF2 is highly expressed in fibrotic renal tissue, although the mechanism remains unclear. We found that FGF2 can activate STAT3 and induce EMT in renal tubular epithelial cells. STAT3, an important transcription factor, was predicted by the JASPAR biological database to bind to the promoter region of YAP1. In this study, STAT3 was shown to promote the expression of the downstream target gene YAP1 through transcription, promote EMT of renal tubular epithelial cells, and mediate the occurrence of renal TIF. This study provides a theoretical basis for the involvement of the FGF2/STAT3/YAP1 signaling pathway in the process of renal interstitial fibrosis and provides a potential target for the treatment of renal fibrosis.

Long Non-Coding RNA GRIK1-AS1 Inhibits the Proliferation and Invasion of Gastric Cancer Cells by Regulating the miR-375/IFIT2 Axis

Long non-coding RNAs (lncRNAs) play important roles in various biological processes and human diseases, including cancer. In this study, we demonstrated a regulatory relationship between lncRNA GRIK1-AS1 and miR-375/IFIT2 axis in gastric cancer. Our results show a decreased expression of GRIK1-AS1 in gastric cancer tissues compared to adjacent normal gastric tissues. Gastric cell lines also have reduced levels of GRIK1-AS1 compared to gastric epithelial cell line GES-1. Ectopic expression of GRIK1-AS1 in gastric cancer cell lines significantly inhibits cellular viability, migration, and invasion. RNA-pull down and the luciferase activity assays show that GRIK1-AS1 mainly interacts specifically with miR-375. We further demonstrate a negatively regulatory relationship between lncRNA GRIK1-AS1 and miR-375. We discovered that IFIT2 was one of the direct key downstream target genes of miR-375, and established the important role of the GRIK1-AS1/miR-375/IFIT2 axis in the progression of gastric cancer. Taken together, our results revealed a novel mechanism of GRIK1-AS1 as a sponge to miR-375 that impacts gastric cancer progression via modulating target mRNA IFIT2 translation, and as a result, opens a new strategy to future GRIK1-AS1 based therapeutic development.

MicroRNA-375: potential cancer suppressor and therapeutic drug

MiR-375 is a conserved noncoding RNA that is known to be involved in tumor cell proliferation, migration, and drug resistance. Previous studies have shown that miR-375 affects the epithelial-mesenchymal transition (EMT) of human tumor cells via some key transcription factors, such as Yes-associated protein 1 (YAP1), Specificity protein 1 (SP1) and signaling pathways (Wnt signaling pathway, nuclear factor κB (NF-κB) pathway and transforming growth factor β (TGF-β) signaling pathway) and is vital for the development of cancer. Additionally, recent studies have identified microRNA (miRNA) delivery system carriers for improved in vivo transportation of miR-375 to specific sites. Here, we discussed the role of miR-375 in different types of cancers, as well as molecular mechanisms, and analyzed the potential of miR-375 as a molecular biomarker and therapeutic target to improve the efficiency of clinical diagnosis of cancer.

Cancer driver gene and non-coding RNA alterations as biomarkers of brain metastasis in lung cancer: A review of the literature

Brain metastasis (BM) is the most common event in patients with lung cancer. Despite multimodal treatments and advances in systemic therapies, development of BM remains one of the main factors associated with poor prognosis and mortality in patients with lung cancer. Therefore, better understanding of mechanisms involved in lung cancer brain metastasis (LCBM) is of great importance to suppress cancer cells and to improve the overall survival of patients. Several cancer-related genes such as EGFR and KRAS have been proposed as potential predictors of LCBM. In addition, there is ample evidence supporting crucial roles of non-coding RNAs (ncRNAs) in mediating LCBM. In this review, we provide comprehensive information on risk assessment, predictive, and prognostic panels for early detection of BM in patients with lung cancer. Moreover, we present an overview of LCBM molecular mechanisms, cancer driver genes, and ncRNAs which may predict the risk of BM in lung cancer patients. Recent clinical studies have focused on determining mechanisms involved in LCBM and their association with diagnosis, prognosis, and treatment outcomes. These studies have shown that alterations in EGFR, KRAS, BRAF, and ALK, as the most frequent coding gene alterations, and dysregulation of ncRNAs such as miR-423, miR-330-3p, miR-145, piR-651, and MALAT1 can be considered as potential biomarkers of LCBM.

The regulatory networks of the Hippo signaling pathway in cancer development

The Hippo signaling pathway is a relatively young tumor-related signaling pathway. Although it was discovered lately, research on it developed rapidly. The Hippo signaling pathway is closely relevant to the occurrence and development of tumors and the maintenance of organ size and other biological processes. This manuscript focuses on YAP, the core molecule of the Hippo signaling pathway, and discussion the upstream and downstream regulatory networks of the Hippo signaling pathway during tumorigenesis and development. It also summarizes the relevant drugs involved in this signaling pathway, which may be helpful to the development of targeted drugs for cancer therapy.

miR-337-5p promotes the development of cardiac hypertrophy by targeting Ubiquilin-1 (UBQLN1)

Cardiac hypertrophy is an adaptive response of the myocardium to the pressure overload of the heart. MicroRNAs (miRNAs/miRs) are shown to be directly involved in the development of cardiac hypertrophy. However, the function of miR-337-5p and its potential contribution to the serine/threonine-protein kinase, a mammalian target of rapamycin (mTOR) signaling in cardiac hypertrophy remains unknown. In the present study, miR-337-5p expression was examined in cardiomyocytes treated with angiotensin II (Ang II). An adenovirus vector system was employed to knockdown miR-337-5p expression to investigate its functions in cardiac hypertrophy. The results revealed a significant increase in the expression of miR-337-5p in cardiomyocytes treated with Ang II as compared with controls. In addition, downregulation of miR-337-5p expression inhibited cardiac hypertrophy both in vitro and in vivo. Dual-luciferase reporter assays demonstrated Ubiquilin-1 (UBQLN1) as the direct target of miR-337-5p, and revealed its function in the modulation of mTOR signaling. Rescue experiments indicated that UBQLN1 overexpression reversed the effects of miR-337-5p, and further verified this interaction. In summary, the results of the present study show that miR-337-5p silencing attenuates cardiac hypertrophy by targeting UBQLN1. Therefore, miR-337-5p plays a critical role in cardiac hypertrophy and may serve as a new therapeutic target.

Role of Yes-associated Protein-1 in Gastrointestinal Cancers and Hepatocellular Carcinoma

Yes-associated protein-1 (YAP1) is a potent transcriptional co-activator and functions as an important downstream effector of the Hippo signaling pathway, which is key to regulating cell proliferation, apoptosis, and organ growth. YAP1 has been implicated as an oncogene for various human cancers including gastrointestinal cancers and hepatocellular carcinoma (HCC). YAP1 promotes tumorigenesis and cancer progression by multiple mechanisms, such as by promoting malignant phenotypes, expanding cancer stem cells, and inducing epithelial-mesenchymal transition. YAP1 overexpression or its activated forms are associated with advanced pathological grades and poor prognosis of cancer, and therefore targeting YAP1 may open a fertile avenue for cancer therapy. In this review, we summarize the recent evidence regarding the role of YAP1 in the carcinogenesis of gastrointestinal cancers and HCC.

The Role of miRNA in the Pathophysiology of Neuroendocrine Tumors

Neuroendocrine tumors (NETs) represent a tumor group that is both rare and heterogeneous. Prognosis is largely determined by the tumor grading and the site of the primary tumor and metastases. Despite intensive research efforts, only modest advances in diagnostic and therapeutic approaches have been achieved in recent years. For patients with non-respectable tumor stages, prognosis is poor. In this context, the development of novel diagnostic tools for early detection of NETs and prediction of tumor response to therapy as well as estimation of the overall prognosis would greatly improve the clinical management of NETs. However, identification of novel diagnostic molecules is hampered by an inadequate understanding of the pathophysiology of neuroendocrine malignancies. It has recently been demonstrated that microRNA (miRNA), a family of small RNA molecules with an established role in the pathophysiology of quite different cancer entities, may also play a role as a biomarker. Here, we summarize the available knowledge on the role of miRNAs in the development of NET and highlight their potential use as serum-based biomarkers in the context of this disease. We discuss important challenges currently preventing their use in clinical routine and give an outlook on future directions of miRNA research in NET.

Helicobacter pylori induces gastric cancer via down-regulating miR-375 to inhibit dendritic cell maturation

BACKGROUND

Recent studies and clinical samples have demonstrated that Helicobacter pylori could induce the downregulation of miR-375 in the stomach and promote gastric carcinogenesis. However, whether the immune cells are affected by Helicobacter pylori due to the downregulation of miR-375 is unclear.

MATERIALS AND METHODS

In this study, we constructed an overexpression and knockdown of miR-375 and Helicobacter pylori infection cell models in vitro. In addition, the maturity of dendritic cells (DCs) and the expression of IL-6, IL-10, and VEGF at the transcriptional and translational levels were analyzed. Changes in the JAK2-STAT3 signaling pathway were detected. In vivo, the number changes in CD4+ T and CD8+ T cells and the size changes of tumors via models of transplantable subcutaneous tumors were also analyzed.

RESULTS

A cell model of Helicobacter pylori and gastric cancer was used to identify the expression of miR-375 and the maturity of dendritic cells. This study found that Helicobacter pylori could downregulate miR-375, which regulates the expression of cytokines IL-6, IL-10, and VEGF in the stomach. MiR-375 regulated the expression of cytokines IL-6, IL-10, and VEGF through the JAK2-STAT3 signaling pathway in vitro. In addition, we found that Helicobacter pylori regulates the maturation of dendritic cells through miR-375. These results were further verified in vivo, and miR-375 diminishes tumor size was also demonstrated. This study showed that immature DCs caused a decrease in the number of CD4+ and CD8+ T cells.

CONCLUSIONS

This study demonstrated that Helicobacter pylori can inhibit miRNA-375 expression in the stomach. Downregulated miR-375 activates the JAK2-STAT3 pathway. Activating the JAK2-STAT3 signaling pathway promotes the secretion of IL-6, IL-10, and VEGF, leading to immature differentiation of DCs and induction of gastric cancer.

WBP2 promotes gastric cancer cell migration via novel targeting of LATS2 kinase in the Hippo tumor suppressor pathway

Dysregulation of signaling pathways is responsible for many human diseases. The lack of understanding of the molecular etiology of gastric cancer (GC) poses a substantial challenge to the development of effective cancer therapy. To better understand the molecular mechanisms underlying the pathogenesis of GC, which will facilitate the identification and development of effective therapeutic approaches to improve patient outcomes, mass spectrometry-based phosphoproteomics analysis was performed to map the global molecular changes in GC. A total of 530 proteins with altered phosphorylation levels were detected across a panel of 15 normal and GC cell lines. WW domain-binding protein 2 (WBP2) was validated to be upregulated in a subset of GC cell lines. WBP2 is overexpressed in 61% cases of GC compared to non-cancer tissues and high WBP2 expression correlates with poor clinical outcomes. WBP2 was found to be required for GC cell migration but is dispensable for cell growth and proliferation. WBP2 knockdown increased p-LATS2 with a concomitant increase in p-YAP, resulting in the cytoplasmic retention of YAP and ultimately the inhibition of YAP/TEAD activity and downregulation of TEAD target genes--CTGF and CYR61. Importantly, the loss of LATS2 reversed the activation of Hippo pathway caused by WBP2 knockdown, indicating that WBP2 acts through LATS2 to exert its function on the Hippo pathway. Moreover, WBP2 interacted with LATS2 to inhibit its phosphorylation and activity. In conclusion, our study established a pivotal role for WBP2 in the promotion of GC cell migration via a novel mechanism that inactivates the Hippo pathway transducer LATS2.

MicroRNAs are involved in the development and progression of gastric cancer

MicroRNAs (miRNAs) are recognized as an essential component of the RNA family, exerting multiple and intricate biological functions, particularly in the process of tumorigenesis, proliferation, and metastatic progression. MiRNAs are altered in gastric cancer (GC), showing activity as both tumor suppressors and oncogenes, although their true roles have not been fully understood. This review will focus upon the recent advances of miRNA studies related to the regulatory mechanisms of gastric tumor cell proliferation, apoptosis, and cell cycle. We hope to provide an in-depth insight into the mechanistic role of miRNAs in GC development and progression. In particular, we summarize the latest studies relevant to miRNAs' impact upon the epithelial-mesenchymal transition, tumor microenvironment, and chemoresistance in GC cells. We expect to elucidate the molecular mechanisms involving miRNAs for better understanding the etiology of GC, and facilitating the development of new treatment regimens for the treatment of GC.

The interplay between m6A modification and non-coding RNA in cancer stemness modulation: mechanisms, signaling pathways, and clinical implications

Cancer stemness, mainly consisting of chemo-resistance, radio-resistance, tumorigenesis, metastasis, tumor self-renewal, cancer metabolism reprogramming, and tumor immuno-microenvironment remodeling, play crucial roles in the cancer progression process and has become the hotspot of cancer research field in recent years. Nowadays, the exact molecular mechanisms of cancer stemness have not been fully understood. Extensive studies have recently implicated that non-coding RNA (ncRNA) plays vital roles in modulating cancer stemness. Notably, N6-methyladenosine (m6A) modification is of crucial importance for RNAs to exert their biological functions, including RNA splicing, stability, translation, degradation, and export. Emerging evidence has revealed that m6A modification can govern the expressions and functions of ncRNAs, consequently controlling cancer stemness properties. However, the interaction mechanisms between ncRNAs and m6A modification in cancer stemness modulation are rarely investigated. In this review, we elucidate the recent findings on the relationships of m6A modification, ncRNAs, and cancer stemness. We also focus on some key signaling pathways such as Wnt/β-catenin signaling, MAPK signaling, Hippo signaling, and JAK/STAT3 signaling to illustrate the underlying interplay mechanisms between m6A modification and ncRNAs in cancer stemness. In particular, we briefly highlight the clinical potential of ncRNAs and m6A modifiers as promising biomarkers and therapeutic targets for indicating cancer stemness properties and improving the diagnostic precision for a wide variety of cancers.

Circ_0072088 promotes progression of hepatocellular carcinoma by activating JAK2/STAT3 signaling pathway via miR-375

Circular RNAs feature prominently in cancer development. Nonetheless, the role of circ_0072088 in hepatocellular carcinoma (HCC) remains unclear. GEO databases (GSE97332, GSE108724, GSE36915, and GSE33006) were used to screen out the differentially expressed circRNAs, miRNAs, and mRNA in HCC. The expressions of circ_0072088, miR-375, and Janus Kinase 2 (JAK2) mRNA in HCC tissue and cell lines were determined with quantitative real-time polymerase chain reaction. RNase R treatment assay was used to measure the stability of circ_0072088, and subcellular fraction assay was used to detect the localization of circ_0072088. Cell counting kit-8 assay, flow cytometry, and Transwell assay were used to measure proliferation, apoptosis, migration, and invasion of HCC cells. RNA immunoprecipitation and dual-luciferase reporter gene assay were employed for investigating the binding sequence between circ_0072088 and miR-375, as well as miR-375 and JAK2 3'UTR. Western blot assay was used to detect the expression of JAK2 and p-STAT3 after circ_0072088 and miR-375 were selectively regulated. Circ_0072088 and JAK2 mRNA expressions were highly expressed in HCC tissues and cell lines while miR-375 expression was remarkably downregulated. Circ_0072088 was resistant to RNase R treatment and mainly located in the cytoplasm of HCC cells. The transfection of circ_0072088 overexpression plasmid or miR-375 inhibitors promoted the proliferation, migration, and invasion, and inhibited the apoptosis of HCC cells, whereas transfection of circ_0072088 siRNA or miR-375 mimics exerted opposite effects. Besides, miR-375 was confirmed as a target of circ_0072088 and miR-375 could further downregulate the expression of JAK2. MiR-375 mimics could reverse the upregulation of JAK2 and p-STAT3 protein induced by circ_0072088 overexpression. Circ_0072088 can enhance the proliferation, migration, and invasion, and impede apoptosis of HCC cells. Mechanistically, circ_0072088 activates JAK2/STAT3 signaling pathway by serving as a molecular sponge of miR-375.