Hippo-YAP signaling pathway: A new paradigm for cancer therapy

The role of cyclic adenosine monophosphate (cAMP) in pathophysiology of fibrosis

Fibrosis, the excessive production and disorganised deposition of extracellular matrix proteins, can occur in any organ system, disrupting functionality and causing fatality. The number, efficacy and safety of antifibrotic drugs are incredibly limited. Therapeutics which elevate intracellular cyclic adenosine monophosphate (cAMP) offer a potential solution. In this review, we present the signalling mechanisms involved in fibrosis pathophysiology, how cAMP and its effectors might interact with these pathways, and the current preclinical and clinical efforts in this field. cAMP elevating agents have the potential to be future antifibrotic drug candidates, but further studies are required, particularly to develop tissue specific therapeutics.

Molecular mechanisms of Hippo pathway in tumorigenesis: therapeutic implications

The Hippo signaling pathway is a pivotal regulator of tissue homeostasis, organ size, and cell proliferation. Its dysregulation is profoundly implicated in various forms of cancer, making it a highly promising target for therapeutic intervention. This review extensively evaluates the mechanisms underlying the dysregulation of the Hippo pathway in cancer cells and the molecular processes linking these alterations to tumorigenesis. Under normal physiological conditions, the Hippo pathway is a guardian, ensuring controlled cellular proliferation and programmed cell death. However, numerous mutations and epigenetic modifications can disrupt this equilibrium in cancer cells, leading to unchecked cell proliferation, enhanced survival, and metastatic capabilities. The pathway's interaction with other critical signaling networks, including Wnt/β-catenin, PI3K/Akt, TGF-β/SMAD, and EGFR pathways, further amplifies its oncogenic potential. Central to these disruptions is the activation of YAP and TAZ transcriptional coactivators, which drive the expression of genes that promote oncogenesis. This review delves into the molecular mechanisms responsible for the dysregulation of the Hippo pathway in cancer, elucidating how these disruptions contribute to tumorigenesis. We also explore potential therapeutic strategies, including inhibitors targeting YAP/TAZ activity and modulators of upstream signaling components. Despite significant advancements in understanding the Hippo pathway's role in cancer, numerous questions remain unresolved. Continued research is imperative to unravel the complex interactions within this pathway and to develop innovative and effective therapies for clinical application. In conclusion, the comprehensive understanding of the Hippo pathway's regulatory mechanisms offers significant potential for advancing cancer therapies, regenerative medicine, and treatments for chronic diseases. The translation of these insights into clinical practice will necessitate collaborative efforts from researchers, clinicians, and pharmaceutical developers to bring novel and effective therapies to patients, ultimately improving clinical outcomes and advancing the field of oncology.

The Pivotal Role of LACTB in the Process of Cancer Development

The mitochondrial serine β-lactamase-like protein LACTB has emerged as a critical regulator in cancer biology, distinguished by its unique structural and functional attributes. Defined by its conserved penicillin-binding proteins and β-lactamases (PBP-βLs) domain and SXXK catalytic motif, LACTB demonstrates properties distinct from its prokaryotic homologs, including the ability to polymerize into filaments. These structural characteristics enable LACTB to modulate mitochondrial organization and enzymatic activity, influencing lipid metabolism and indirectly affecting cellular proliferation. Importantly, the expression and functional roles of LACTB exhibit cancer-type-specific variation, underscoring its dual function as both a tumor suppressor and an oncogene. Decreased LACTB expression is associated with poor clinical outcomes in cancers such as breast cancer, lung cancer, and colorectal cancer, while specific mutations and regulatory mechanisms have been linked to its oncogenic activity in osteosarcoma and pancreatic adenocarcinoma. Mechanistically, LACTB regulates key processes in cancer progression, including mitochondrial dynamics, epithelial-mesenchymal transition (EMT), and cell death pathways. This duality highlights LACTB as a promising therapeutic target and underscores its relevance in advancing precision oncology strategies. This review provides a comprehensive analysis of expression level, structure-function relationships, and the diverse roles of LACTB in oncogenesis, underscoring its promise as a focal point for precision cancer therapies.

Regulation of Hippo-YAP1/TAZ pathway in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) has become the most prevalent chronic liver disease worldwide, but effective treatments are still lacking. Metabolic disorders such as iron overload, glycolysis, insulin resistance, lipid dysregulation, and glutaminolysis are found to induce liver senescence and ferroptosis, which are hot topics in the research of MASLD. Recent studies have shown that Hippo-YAP1/TAZ pathway is involved in the regulations of metabolism disorders, senescence, ferroptosis, inflammation, and fibrosis in MASLD, but their complex connections and contrast roles are also reported. In addition, therapeutics based on the Hippo-YAP1/TAZ pathway hold promising for MASLD treatment. In this review, we highlight the regulation and molecular mechanism of the Hippo-YAP1/TAZ pathway in MASLD and summarize potential therapeutic strategies for MASLD by regulating Hippo-YAP1/TAZ pathway.

Unravelling CD24-Siglec-10 pathway: Cancer immunotherapy from basic science to clinical studies

Cancer immunotherapy has revolutionized the treatment landscape by harnessing the power of the immune system to combat malignancies. Two of the most promising players in this field are cluster of differentiation 24 (CD24) and sialic acid-binding Ig-like lectin 10 (Siglec-10), and both of them play pivotal roles in modulating immune responses. CD24, a cell surface glycoprotein, emerges as a convincing fundamental signal transducer for therapeutic intervention, given its significant implication in the processes related to tumour progression and immunogenic evasion. Additionally, the immunomodulatory functions of Siglec-10, a prominent member within the Siglec family of immune receptors, have recently become a crucial point of interest, particularly in the context of the tumour microenvironment. Hence, the intricate interplay of both CD24 and Siglec-10 assumes a critical role in fostering tumour growth, facilitating metastasis and also orchestrating immune evasion. Recent studies have found multiple evidences supporting the therapeutic potential of targeting CD24 in cancer treatment. Siglec-10, on the other hand, exhibits immunosuppressive properties that contribute to immune tolerance within the tumour microenvironment. Therefore, we delve into the complex mechanisms through which Siglec-10 modulates immune responses and facilitates immune escape in cancer. Siglec-10 also acts as a viable target for cancer immunotherapy and presents novel avenues for the development of therapeutic interventions. Furthermore, we examine the synergy between CD24 and Siglec-10 in shaping the immunosuppressive tumour microenvironment and discuss the implications for combination therapies. Therefore, understanding the roles of CD24 and Siglec-10 in cancer immunotherapy opens exciting possibilities for the development of novel therapeutics.

m6A-modified circXPO1 accelerates colorectal cancer progression via interaction with FMRP to promote WWC2 mRNA decay

BACKGROUND

Recent evidence has demonstrated the vital roles of circular RNAs (circRNAs) in the progression of colorectal cancer (CRC); however, their functions and mechanisms in CRC need to be further explored. This study aimed to uncover the biological function of circXPO1 in CRC progression.

METHODS

CircXPO1 was identified by Sanger sequencing, RNase R, and actinomycin D treatment assays. Colony formation, scratch, transwell assays, and mouse xenograft models were adopted to evaluate CRC cell growth and metastasis in vitro and in vivo. Subcellular expression of circXPO1 was detected by FISH and nuclear-cytoplasmic separation assays. Molecular mechanisms were investigated by MeRIP, RIP, and RNA pull-down assays. Target molecular expression was detected by RT-qPCR, Western blotting and immunohistochemical staining.

RESULTS

circXPO1 was up-regulated in CRC tissues and cells, which indicated a poor prognosis of CRC patients. circXPO1 deficiency delayed the growth, EMT, and metastasis of CRC cells. Mechanistical experiments indicated that down-regulation of ALKBH5 enhanced IGF2BP2-mediated m6A modification of circXPO1 to increase circXPO1 expression. Furthermore, circXPO1 interacted with FMRP to reduce the mRNA stability of WWC2, which consequently resulted in Hippo-YAP pathway activation. Rescue experiments suggested that WWC2 overexpression abrogated circXPO1-mediated malignant capacities of CRC cells. The in vivo growth and liver metastasis of CRC cells were restrained by circXPO1 depletion or WWC2 overexpression.

CONCLUSIONS

m6A-modified circXPO1 by ALKBH5/IGF2BP2 axis destabilized WWC2 via interaction with FMRP to activate Hippo-YAP pathway, thereby facilitating CRC growth and metastasis. Targeting circXPO1 might be a potential therapeutic strategy for CRC.

Pan-cancer analysis of the prognostic and immunological role of hippo-YAP signaling pathway

The Hippo-Yes-associated protein (Hippo-YAP) signaling pathway, a conserved pathway that regulates organ size, participates in tumor progression. However, there are few comprehensive analyses of tumor prognosis and immunity. In the present study, TCGA, GTEx, GEO, TIMER2, STRING, GSCA, ImmuCellAI, and other bioinformatics tools were used to reveal the involvement of the Hippo-YAP signaling pathway in the prognosis and immunity of pan-cancers. The obtained results showed that mRNA expression differences of Hippo-YAP pathway genes between normal samples and tumor samples in pan-cancers and some genes (such as TEAD4, MAP4K4, and STK3) might affect the prognosis of patients with skin cutaneous melanoma (SKCM) and pancreatic adenocarcinoma (PAAD). Furthermore, mutation and methylation of the Hippo-YAP signaling pathway genes in normal and primary tumor tissues differ in various cancers (KIRP, BRCA). Additionally, the relationship between the tumor microenvironment, molecular pathways, and the Hippo-YAP pathway indicated that it might lead to a suppressive immune microenvironment that affects the efficacy of immunotherapy. This is a pan-cancer overview of the Hippo-YAP signaling pathway genes, which explores the aberrant expression or mutation of this pathway that regulates the tumor microenvironment and immunotherapy.

Consecutive palmitoylation and phosphorylation orchestrates NLRP3 membrane trafficking and inflammasome activation

NLRP3 inflammasome activation, essential for cytokine secretion and pyroptosis in response to diverse stimuli, is closely associated with various diseases. Upon stimulation, NLRP3 undergoes subcellular membrane trafficking and conformational rearrangements, preparing itself for inflammasome assembly at the microtubule-organizing center (MTOC). Here, we elucidate an orchestrated mechanism underlying these ordered processes using human and murine cells. Specifically, NLRP3 undergoes palmitoylation at two sites by palmitoyl transferase zDHHC1, facilitating its trafficking between subcellular membranes, including the mitochondria, trans-Golgi network (TGN), and endosome. This dynamic trafficking culminates in the localization of NLRP3 to the MTOC, where LATS1/2, pre-recruited to MTOC during priming, phosphorylates NLRP3 to further facilitate its interaction with NIMA-related kinase 7 (NEK7), ultimately leading to full NLRP3 activation. Consistently, Zdhhc1-deficiency mitigated LPS-induced inflammation and conferred protection against mortality in mice. Altogether, our findings provide valuable insights into the regulation of NLRP3 membrane trafficking and inflammasome activation, governed by palmitoylation and phosphorylation events.

Semisynthesis and biological evaluation of novel honokiol thioethers against colon cancer cells HCT116 via inhibiting the transcription and expression of YAP protein

Honokiol, derived from Magnolia officinalis (a traditional Chinese medicine), has been reported to have anticancer activity. Here, a series of novel honokiol thioethers bearing a 1,3,4-oxadiazole moiety were prepared and evaluated for their anticancer activities against three types of digestive system tumor cells. Biological evaluation showed that honokiol derivative 3k exhibited the best antiproliferative activity against HCT116 cells with an IC50 value of 6.1 μmol/L, superior to the reference drug 5-fluorouracil (IC50: 9.63 ± 0.27 µmol/L). The structure-activity relationships (SARs) indicated that the introduction of -(4-NO2)Ph, 3-pyridyl, -(2-F)Ph, -(4-F)Ph, -(3-F)Ph, -(4-Cl)Ph, and -(3-Cl)Ph groups was favorable for enhancing the anticancer activity of the title honokiol thioethers. Further study revealed that honokiol thioether 3k can well inhibit the proliferation of colon cancer cells HCT116, arresting the cells in G1 phase and inducing cell death. Moreover, a preliminary mechanism study indicated that 3k directly inhibits the transcription and expression of YAP protein without activating the Hippo signaling pathway. Thus, honokiol thioether 3k could be deeply developed for the development of honokiol-based anticancer candidates.

The role of zyxin in signal transduction and its relationship with diseases

This review highlighted the pivotal role of zyxin, an essential cell focal adhesions protein, in cellular biology and various diseases. Zyxin can orchestrate the restructuring and dynamic alterations of the cellular cytoskeleton, which is involved in cell proliferation, adhesion, motility, and gene transcription. Aberrant zyxin expression is closely correlated with tumor cell activity and cardiac function in both tumorigenesis and cardiovascular diseases. Moreover, in fibrotic and inflammatory conditions, zyxin can modulate cellular functions and inflammatory responses. Therefore, a comprehensive understanding of zyxin is crucial for deciphering signal transduction networks and disease pathogenesis. Investigating its role in diseases holds promise for novel avenues in early diagnosis and therapeutic strategies. Nevertheless, targeting zyxin as a therapeutic focal point presents challenges in terms of specificity, safety, drug delivery, and resistance. Nonetheless, in-depth studies on zyxin and the application of precision medicine could offer new possibilities for personalized treatment modalities.

SEPHS1 attenuates intervertebral disc degeneration by delaying nucleus pulposus cell senescence through the Hippo-Yap/Taz pathway

Nucleus pulposus cell (NPC) senescence is a major cause of intervertebral disc degeneration (IVDD). Oxidative stress and reactive oxygen species (ROS) play critical roles in regulating cell senescence. Selenophosphate synthetase 1 (SEPHS1) was reported to play an important role in mitigating oxidative stress in an osteoarthritis (OA) model by reducing the production of ROS, thereby, delaying the occurrence and development of osteoarthritis. In this study, we explored the, hitherto unknown, role of SEPHS1 in IVDD in vitro and in vivo using an interleukin-1β (IL-1β)-induced NPC senescence model and a rat needle puncture IVDD model, respectively. SEPHS1 delayed NPC senescence in vitro by reducing ROS production. Age-related dysfunction was also ameliorated by the overexpression of SEPHS1 and inhibition of the Hippo-Yap/Taz signaling pathway. In vivo experiments revealed that the overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz alleviated IVDD in rats. Moreover, a selenium (Se)-deficient diet and lack of SEPHS1 synergistically aggravated IVDD progression. Taken together, our results demonstrate that SEPHS1 plays a significant role in NPC senescence. Overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz can delay NPC senescence, restore the balance of extracellular matrix metabolism, and attenuate IVDD. SEPHS1 could be a promising therapeutic target for IVDD.NEW & NOTEWORTHY Selenophosphate synthetase 1 (SEPHS1) deficiency leads to an increase in reactive oxygen species levels and in the subsequent activation of the Hippo-Yap/Taz signaling pathway. In the rat model of intervertebral disc degeneration (IVDD), overexpression of SEPHS1 and inhibition of Hippo-YAP/Taz mitigated the progression of disc degeneration indicating the involvement of SEPHS1 in IVDD. SEPHS1 is a promising therapeutic target for IVDD.

TAZ facilitates breast tumor growth by promoting an immune-suppressive tumor microenvironment

The core Hippo pathway module consists of a tumour-suppressive kinase cascade that inhibits the transcriptional coactivators Yes-associated protein (YAP) and WW domain-containing transcription regulator protein 1 (WWTR1; also known as TAZ). When the Hippo pathway is downregulated, as often occurs in breast cancer, YAP/TAZ activity is induced. To elaborate the roles of TAZ in triple-negative breast cancer (TNBC), we depleted Taz in murine TNBC 4T1 cells, using either CRISPR/Cas9 or small hairpin RNA (shRNA). TAZ-depleted cells and their controls, harbouring wild-type levels of TAZ, were orthotopically injected into the mammary fat pads of syngeneic BALB/c female mice, and mice were monitored for tumour growth. TAZ depletion resulted in smaller tumours compared to the tumours generated by control cells, in line with the notion that TAZ functions as an oncogene in breast cancer. Tumours, as well as their corresponding in vitro cultured cells, were then subjected to gene expression profiling by RNA sequencing (RNA-seq). Interestingly, pathway analysis of the RNA-seq data indicated a TAZ-dependent enrichment of 'Inflammatory Response', a pathway correlated with TAZ expression levels also in human breast cancer tumours. Specifically, the RNA-seq analysis predicted a significant depletion of regulatory T cells (Tregs) in TAZ-deficient tumours, which was experimentally validated by the staining of tumour sections and by quantitative cytometry by time of flight (CyTOF). Strikingly, the differences in tumour size were completely abolished in immune-deficient mice, demonstrating that the immune-modulatory capacity of TAZ is critical for its oncogenic activity in this setting. Cytokine array analysis of conditioned medium from cultured cells revealed that TAZ increased the abundance of a small group of cytokines, including plasminogen activator inhibitor 1 (Serpin E1; also known as PAI-1), CCN family member 4 (CCN4; also known as WISP-1) and interleukin-23 (IL-23), suggesting a potential mechanistic explanation for its in vivo immunomodulatory effect. Together, our results imply that TAZ functions in a non-cell-autonomous manner to modify the tumour immune microenvironment and dampen the anti-tumour immune response, thereby facilitating tumour growth.

MUC13 drives cancer aggressiveness and metastasis through the YAP1-dependent pathway

Anchorage-independent survival after intravasation of cancer cells from the primary tumor site represents a critical step in metastasis. Here, we reveal new insights into how MUC13-mediated anoikis resistance, coupled with survival of colorectal tumor cells, leads to distant metastasis. We found that MUC13 targets a potent transcriptional coactivator, YAP1, and drives its nuclear translocation via forming a novel survival complex, which in turn augments the levels of pro-survival and metastasis-associated genes. High expression of MUC13 is correlated well with extensive macrometastasis of colon cancer cells with elevated nuclear YAP1 in physiologically relevant whole animal model systems. Interestingly, a positive correlation of MUC13 and YAP1 expression was observed in human colorectal cancer tissues. In brief, the results presented here broaden the significance of MCU13 in cancer metastasis via targeting YAP1 for the first time and provide new avenues for developing novel strategies for targeting cancer metastasis.

High TEAD4 Expression is Associated With Aggressive Clear Cell Renal Cell Carcinoma, Regardless of YAP1 Expression

Yes-associated protein 1 (YAP1) and transcriptional coactivator TEA domain transcription factor 4 (TEAD4) are the main effectors of the Hippo signaling pathway. Deregulation of the Hippo signaling pathway significantly impacts tumorigenesis and tumor progression. We evaluated the mRNA expression level of YAP1 and TEAD4 using the Gene Expression Profiling Interactive Analysis database and investigated the roles of YAP1 and TEAD4 in 349 surgically resected clear cell renal cell carcinoma (CCRCC) samples through immunohistochemical analysis. High YAP1 and TEAD4 expression were observed in 57 (16.3%) and 131 (37.5%) cases, respectively. High YAP1 expression was associated with a low nuclear grade only. High TEAD4 expression was significantly associated with large tumor size, high nuclear grade, lymphovascular invasion, advanced pT classification, advanced clinical stage, sarcomatous differentiation, and metastasis. CCRCC with YAP1-low/TEAD4-high expression was significantly associated with aggressive clinicopathological variables and poor outcomes. For CCRCC, higher tumor stage, sarcomatous differentiation, and metastasis were the independent prognostic factors for overall survival (OS) and disease-free survival (DFS). High TEAD4 expression was significantly associated with short OS and DFS but was not an independent prognostic factor. High TEAD4 and YAP1-low/TEAD4-high expression significantly correlated with adverse clinicopathological factors and worse OS and DFS in patients with CCRCC. YAP1 expression was not significantly associated with clinicopathological factors or patient survival. Therefore, TEAD4 plays a critical role in CCRCC tumor progression independent of YAP1 and may be a potential biomarker and therapeutic target for CCRCC.

Syndecan-2 modulates the YAP pathway in epithelial-to-mesenchymal transition-related migration, invasion, and drug resistance in colorectal cancer

Epithelial-to-mesenchymal transition (EMT) is associated with an invasive phenotype in colorectal cancer (CRC). Here, we examined the roles of YES-associated protein (YAP) and syndecan-2 (SDC2) in EMT-related progression, invasion, metastasis, and drug resistance in CRC. The expression levels of YAP and SDC2 in CRC patient tumor tissue were quantified by PCR and western blotting. EMT-associated characteristics were assessed using Transwell assays and immunohistochemistry. Co-immunoprecipitation, glutathione S-transferase pull-down, and luciferase reporter assays were used to assess interactions between YAP and SDC2. YAP was found to be highly expressed in tumor tissue from 13/16 CRC patients, while SDC2 was highly expressed in the tumor tissue of 12/16 CRC patients. Overexpression of YAP in colon cancer cells led to increased cell viability, invasion, migration, and oxaliplatin resistance demonstrating that YAP plays a role in EMT. In addition, overexpression of YAP led to decreased expression of the large tumor suppressor kinase 1 (LATS1) and mammalian sterile 20-like kinases (MST1/2). Decreased LATS1 expression was associated with increased levels of cell proliferation. Knockdown of YAP by shRNA interference led to decreased cell invasion, migration, and drug resistance in colon cancer cells and reduced tumorigenesis in a mouse xenograft model. Finally, we established that YAP interacted with SDC2, and demonstrated that SDC2 mediated the YAP pathway through the EMT-related factors BMP4, CTGF and FOXM1.

SHOX2 promotes prostate cancer proliferation and metastasis through disruption of the Hippo-YAP pathway

The transcription factor SHOX2 gene is critical in regulating gene expression and the development of tumors, but its biological role in prostate cancer (PCa) remains unclear. In this study, we found that SHOX2 expression was significantly raised in PCa tissues and was associated with clinicopathological features as well as disease-free survival (DFS) of PCa patients. Phenotypic tests showed that the absence of SHOX2 inhibited PCa growth and invasion, while SHOX2 overexpression promoted these effects. Mechanistically, SHOX2 was found to activate the transcription of nephronophthisis type 4 (NPHP4), a gene located downstream of SHOX2. Further analysis revealed that SHOX2 could potentially interfere with the Hippo-YAP signaling pathway through NPHP4 activation, facilitating the oncogenic behavior of PCa cells. These findings highlight SHOX2 as an oncogene in PCa and provide a basis for developing potential therapeutic approaches against this disease.

Ursolic Acid Inhibits the Growth of Gastric Cancer by Targeting KLF4/YAP1

Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor which has various mechanisms in different tumors. Ursolic acid (UA), a natural compound that exists in many herbs, is known to prevent tumor progression and has anticancer effects on many human cancers. The present study was to evaluate the antitumor effect of UA on gastric cancer (GC) through KLF4 and the Hippo pathway. Our data showed that UA inhibited the growth of GC in vivo and in vitro. UA treatment significantly increased the expression of KLF4 and decreased the expression of CTGF. The overexpression of KLF4 inhibited the proliferation and cell cycle of GC and decreased the expression of CTGF, whereas the knockdown of KLF4 attenuated the effects of UA. Furthermore, the inhibition of CTGF arrested tumor cells in G2/M which blocked proliferation progress. Confocal laser scanning and molecular simulation software MOE showed that KLF4 combined with YAP1 which may block the formation of the TEADs-YAP1 complex to interrupt the expression of CTGF and the downstream oncogenic process. In conclusion, UA can inhibit GC growth both in vivo and in vitro, and it activated KLF4 which may competitively bind with YAP1 against TEADs and block the oncogenic Hippo pathways.

YAP inhibitor verteporfin suppresses tumor angiogenesis and overcomes chemoresistance in esophageal squamous cell carcinoma

PURPOSE

Targeting angiogenesis is an attractive strategy for the effective treatment of cancer. This study aimed to investigate the anti-cancer activities of YAP inhibitor verteporfin (VP) in esophageal squamous cell carcinoma (ESCC) cells through its inhibitory effect on tumor angiogenesis.

METHODS

Cell proliferation, apoptosis, migration and invasion abilities were estimated by MTT, colony formation, DAPI staining, wound healing and transwell assays, respectively. Human umbilical vein endothelial cell (HUVEC) tube formation assay and chick embryo chorioallantoic membrane (CAM) model were used to observe angiogenesis in vitro and in vivo. The interactions between ESCC cells and HUVECs were assessed by cell chemotactic migration and adhesion assays. The expression levels of angiogenesis-related molecules were detected by Western blot.

RESULTS

We found that VP was potential to inhibit ESCC cell proliferation, migration, invasion and induce apoptosis in the dose-dependent fashion. VP also significantly suppressed proliferation, migration, and tube formation of HUVECs and promoted apoptosis of HUVECs, and reduced angiogenesis in CAM. Moreover, VP inhibited ESCC cell-induced angiogenesis in vitro by decreasing HUVEC chemotactic migration, adhesion and tube formation, and also reduced ESCC cell-induced neovascularization of the CAM in vivo. In addition, VP suppressed the expression of pro-angiogenic molecules such as VEGFA, MMP-2 and β-catenin in ESCC cells. Furtherly, VP increased the chemosensitivity of ESCC-resistant cells to paclitaxel (PTX). The combination of VP and PTX attenuated the resistant cell-mediated angiogenesis in vitro and in vivo.

CONCLUSION

These results reveal for the first time that VP potently inhibits malignant progression and overcomes chemoresistance of ESCC cells via inhibition of tumor angiogenesis. It provides insight into a new strategy for the treatment of ESCC that VP could be a potential drug candidate for targeting tumor angiogenesis.

Roles of Hippo-YAP/TAZ signalling in intervertebral disc degeneration

Intervertebral disc degeneration (IVDD), a common cartilage-degenerative disease, is considered the main cause of low back pain (LBP). Owing to the complex aetiology and pathophysiology of IVDD, its molecular mechanisms and definitive treatment of IVDD remain unclear. As an evolutionarily and functionally conserved signalling pathway, Hippo-YAP/TAZ signalling plays a crucial role in IVDD progression. In this review, we discuss the regulation of Hippo-YAP/TAZ signalling and summarise the recent research progress on its role in cartilage homeostasis and IVDD. We also discuss the current application and future prospects of IVDD treatments based on Hippo-YAP/TAZ signalling.

Secure transplantation by tissue purging using photodynamic therapy to eradicate malignant cells

The field of photodynamic therapy (PDT) for treating various malignant neoplasms has been given researchers' attention due to its ability to be a selective and minimally invasive cancer therapy strategy. The possibility of tumor cell infection and hence high recurrence rates in cancer patients tends to restrict autologous transplantation. So, the photodynamic tissue purging process, which consists of selective photoinactivation of the malignant cells in the graft, is defined as a compromising strategy to purify contaminated tissues before transplantation. In this strategy, the direct malignant cells' death results from the reactive oxygen species (ROS) generation through the activation of a photosensitizer (PS) by light exposure in the presence of oxygen. Since new PS generations can effectively penetrate the tissue, PDT could be an ideal ex vivo tissue purging protocol that eradicates cancer cells derived from various malignancies. The challenge is that the applied pharmacologic ex vivo tissue purging should efficiently induce tumor cells with minor influence on normal tissue cells. This review aims to provide an overview of the current status of the most effective PDT strategies and PS development concerning their potential application in ex vivo purging before hematopoietic stem cell or ovarian tissue transplantation.

miR-375 Regulates the Proliferation, Apoptosis and Colony Formation of Thyroid Cancer Cells via Targeting YAP1

Objective: Yes-associated protein 1 (YAP1) regulates cell proliferation and apoptosis. Abnormal miR-375 level was related to thyroid cancer. Software predicted a relationship between miR-375 and YAP1. Our study investigated whether miR-375 regulates YAP1 expression and affects thyroid cancer cells. Methods: The tumor tissues and adjacent tissues of thyroid cancer patients were collected to measure miR-375 and YAP1 expression. The dual luciferase reporter experiment verified the regulation between miR-375 and YAP1. Thyroid cancer cell line B-CPAP and TPC-1 cells were divided into miR-NC group and miR-375 mimic group followed by analysis of cell proliferation by flow cytometry, caspase-3 activity, and cell clone formation ability by plate cloning assay. Results: Compared with adjacent cancer tissues, miR-375 in thyroid cancer tissues was decreased and YAP1 was increased. miR-375 targets YAP1. Compared with Nthy-ori 3-1 cells, miR-375 in B-CPAP and TPC-1 cells was significantly reduced and YAP1 was increased. Transfection with miR-375 mimic significantly inhibited cell proliferation, increase caspase-3 activity, and reduced the ability of cells to form clones. Conclusion: miR-375 can inhibit YAP1 expression, decrease the proliferation of thyroid cancer cells, induce cell apoptosis, and reduce clone formation.

Circular RNA circ_0067741 regulates the Hippo/YAP pathway to suppress lung adenocarcinoma progression by targeting microRNA-183-5p

To discuss the effect and molecular mechanism of circular RNA circ_0067741 on the occurrence and development of lung adenocarcinoma (LUAD). QRT-PCR was utilized to detect circ_0067741, microRNA-183-5p (miR-183-5p) and large tumor suppressor 1 (LATS1) expressions in tumor tissues of 30 LUAD patients and LUAD cell lines (A549, Calu-3, H1299 and H1975). After overexpression or knockdown of circ_0067741-1 or miR-183-5p in H1299 and A549 cells, respectively, cell proliferation, viability, apoptosis, invasion and migration ability and angiogenesis ability were detected by MTT, cell cloning, flow cytometry, transwell and tube formation assays, respectively. The targeted relationship between miR-183-5p and circ_0067741 or LATS1 was validated using dual-luciferase reporter assay. We found that circ_0067741 expression was notably declined in LUAD cells and tissues. Overexpression of circ_0067741 inhibited the proliferation, migration, invasion, and angiogenesis of LUAD cells and promoted apoptosis. Moreover, circ_0067741 could sponge miR-183-5p to regulate LATS1 expression and then activate the Hippo/YAP pathway. Downregulation of LATS1 reversed the effects of circ_0067741 on the Hippo/YAP pathway and LUAD cells progression. In conclusion, circ_0067741 sponges miR-183-5p, and regulates LATS1 to activate Hippo/YAP pathway, thereby inhibiting the process of LUAD cells. And the circ_0067741/miR-183-5p/LATS1 axis can be a potential target for early diagnosis and targeted treatment of LUAD.

Long-range structural preformation in yes-associated protein precedes encounter complex formation with TEAD

Yes-associated protein (YAP) is a partly intrinsically disordered protein (IDP) that plays a major role as the downstream element of the Hippo pathway. Although the structures of the complex between TEA domain transcription factors (TEADs) and the TEAD-binding domain of YAP are already well characterized, its apo state and the binding mechanism with TEADs are still not clearly defined. Here we characterize via a combination of different NMR approaches with site-directed mutagenesis and affinity measurements the intrinsically disordered solution state of apo YAP. Our results provide evidence that the apo state of YAP adopts several compact conformations that may facilitate the formation of the YAP:TEAD complex. The interplay between local secondary structure element preformation and long-range co-stabilization of these structured elements precedes the encounter complex formation with TEAD and we, therefore, propose that TEAD binding proceeds largely via conformational selection of the preformed compact substates displaying at least nanosecond lifetimes.

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Secondary structure elements are preformed in apo YAP

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Preformation of secondary structure elements is co-dependent

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Apo YAP exhibits long-range structural compaction

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YAP compaction has a kinetic contribution to the YAP:TEAD formation

Target Therapy for Hepatocellular Carcinoma: Beyond Receptor Tyrosine Kinase Inhibitors and Immune Checkpoint Inhibitors

Simple Summary

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and its incidence is steadily increasing. The development of HCC is a complex, multi-step process that is accompanied by alterations in multiple signaling cascades. Recent years have seen advancement in understanding molecular signaling pathways that play central roles in hepatocarcinogenesis. Aberrant activation of YAP/TAZ, Hedgehog, or Wnt/β-catenin signaling is frequently found in a subset of HCC patients. Targeting the signaling pathway via small molecule inhibitors could be a promising therapeutic option for the subset of patients. In this review, we will introduce the signaling pathways, discuss their roles in the development of HCC, and propose a therapeutic approach targeting the signaling pathways in the context of HCC.

Abstract

Hepatocellular carcinoma (HCC) is a major health concern worldwide, and its incidence is increasing steadily. To date, receptor tyrosine kinases (RTKs) are the most favored molecular targets for the treatment of HCC, followed by immune checkpoint regulators such as PD-1, PD-L1, and CTLA-4. With less than desirable clinical outcomes from RTK inhibitors as well as immune checkpoint inhibitors (ICI) so far, novel molecular target therapies have been proposed for HCC. In this review, we will introduce diverse molecular signaling pathways that are aberrantly activated in HCC, focusing on YAP/TAZ, Hedgehog, and Wnt/β-catenin signaling pathways, and discuss potential therapeutic strategies targeting the signaling pathways in HCC.

The RhoGEF Trio: A Protein with a Wide Range of Functions in the Vascular Endothelium

Many cellular processes are controlled by small GTPases, which can be activated by guanine nucleotide exchange factors (GEFs). The RhoGEF Trio contains two GEF domains that differentially activate the small GTPases such as Rac1/RhoG and RhoA. These small RhoGTPases are mainly involved in the remodeling of the actin cytoskeleton. In the endothelium, they regulate junctional stabilization and play a crucial role in angiogenesis and endothelial barrier integrity. Multiple extracellular signals originating from different vascular processes can influence the activity of Trio and thereby the regulation of the forementioned small GTPases and actin cytoskeleton. This review elucidates how various signals regulate Trio in a distinct manner, resulting in different functional outcomes that are crucial for endothelial cell function in response to inflammation.

Computational design and experimental substantiation of conformationally constrained peptides from the complex interfaces of transcriptional enhanced associate domains with their cofactors in gastric cancer

Transcriptional enhanced associate domains (Teads) are the downstream effectors of the hippo signaling pathway and have been recognized as attractive druggable targets of gastric cancer. The biological function of Teads is regulated by diverse cofactors. In this study, the intermolecular interactions of Teads with their cognate cofactors were systematically characterized at structural, thermodynamic and dynamic levels. The Teads possess a double-stranded helical hairpin that is surrounded by three independent structural elements β-sheet, α-helix and Ω-loop of cofactor proteins and plays a central role in recognition and association with cofactors. A number of functional peptides were split from the hairpin region at Tead-cofactor complex interfaces, which, however, cannot maintain in native conformation without the support of protein context and would therefore incur a considerable entropy penalty upon competitively rebinding to the interfaces. Here, we further used disulfide and hydrocarbon bridges to cyclize and staple the hairpin and helical peptides, respectively. The chemical modification strategies were demonstrated to effectively constrain peptide conformation into active state and to largely reduce peptide flexibility in free state, thus considerably improving their affinity. Since the cyclization and stapling only minimize the indirect entropy cost but do not influence the direct enthalpy effect upon peptide binding, the designed conformationally constrained peptides can retain in their native selectivity over different cofactors. This is particularly interesting because it means that the cyclized/stapled, affinity-improved peptides can specifically compete with their parent Teads for the cofactor arrays as they share consistent target specificity.

MicroRNAs in blood act as biomarkers of colorectal cancer and indicate potential therapeutic targets

Association studies have linked alterations of blood-derived microRNAs (miRNAs) with colorectal cancer (CRC). Here, we performed a microarray-based comparison of the profiles of 2549 miRNAs in 80 blood samples from healthy donors and patients with colorectal adenomas, colorectal diverticulitis and CRC at different stages. Confirmation by quantitative real-time PCR (RT-PCR) was complemented by validation of identified molecules in another 36 blood samples. No variations in miRNA levels were observed in samples from patients with colorectal adenomas and diverticulitis or from healthy donors. However, there were 179 CRC-associated miRNAs of differential abundance compared to healthy controls. Only three - miR-1225-5p, miR-1207-5p and miR-4459 - exhibited increased levels at all CRC stages. Most deregulated miRNAs (128/179, 71%) specifically predicted metastatic CRC. Pathway analysis found several cancer-related pathways to which the miRNAs contribute in various ways. In conclusion, miRNA levels in blood vary throughout CRC progression and affect cellular functions relevant to haematogenous CRC progression and dissemination. The identified biomarker and therapeutic candidates require further confirmation of their clinical relevance.

Transcatheter arterial chemoembolization combined with Hippo/YAP inhibition significantly improve the survival of rats with transplanted hepatocellular carcinoma

Background

This study aimed to explore the effect of inhibiting the Hippo/Yes-associated protein (YAP) signaling pathway on the outcomes of transcatheter arterial chemoembolization (TACE) in treating transplanted hepatocellular carcinoma (HCC).

Methods

A transplanted HCC rat model was established. Then, rats were randomly divided into four groups: Sham, TACE, verteporfin (inhibitor of Hippo/YAP), and TACE+verteporfin. Lent-OE-YAP was transfected into rats to overexpress YAP in vivo. After treatments, morphological changes, tumor weight, and the overall survival of rats in different groups were analyzed. Real-time PCR, immunohistochemistry staining, and Western blotting were used to determine the expression of factors related to the Hippo/YAP signaling pathway.

Results

Tumor weight and tissue lesions in the TACE and verteporfin groups were significantly reduced compared with the Sham group. Verteporfin significantly decreased tumor weight after TACE treatment. In addition, verteporfin significantly improved the overall survival of rats with transplanted HCC after TACE treatment. Compared with the Sham group, both TACE and verteporfin groups exhibited significantly decreased expression of macrophage-stimulating (MST)1, MST2, long-acting thyroid stimulator 1, transcriptional co-activator with PDZ-binding motif (TAZ), Yes-associated protein (YAP), TEA domain transcription factor (TEAD)1, TEAD2, TEAD3, and TEAD4. TACE plus verteporfin significantly enhanced the downregulation of effectors in the Hippo/YAP signaling pathway and decreased tumor size, while the overexpression of YAP exerted opposite effects.

Conclusion

The inhibition of the Hippo/YAP signaling pathway via verteporfin significantly improved the outcomes of TACE in treating transplanted HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01486-w.

YAP/TEAD4-induced KIF4A contributes to the progression and worse prognosis of esophageal squamous cell carcinoma

Aberrant expression of kinesin family member 4A (KIF4A), which is associated with tumor progression, has been reported in several types of cancer. However, its expression and the underlying molecular mechanisms regulating the transcription of KIF4A in esophageal squamous cell carcinoma (ESCC) remain largely unclear. Here, we found that high KIF4A expression was positively correlated with tumor stage and poor prognosis in ESCC patients. KIF4A silencing significantly inhibited the growth and migration of ESCC cells, arrested cell cycle, and induced apoptosis. Interestingly, KIF4A expression was positively related to the expression of YAP in human ESCC tissues. YAP knockdown or disrupting YAP/TEAD4 interaction by verteporfin repressed KIF4A expression. Also, KIF4A knockdown significantly inhibited the cell growth induced by YAP overexpression. Mechanistically, YAP activated KIF4A transcriptional expression by TEAD4-mediated direct binding to KIF4A promoter. Finally, KIF4A knockdown and verteporfin treatment synergistically inhibited tumor growth in xenograft models. Together, these results indicated that KIF4A, a novel target gene of YAP/TEAD4, may be a progression and prognostic biomarker of ESCC. Targeting drugs for KIF4A combined with YAP inhibitor may be a novel therapeutic strategy for ESCC.

Utilizing the Hippo pathway as a therapeutic target for combating endocrine-resistant breast cancer

Drug resistance is always a great obstacle in any endocrine therapy of breast cancer. Although the combination of endocrine therapy and targeted therapy has been shown to significantly improve prognosis, refractory endocrine resistance is still common. Dysregulation of the Hippo pathway is often related to the occurrence and the development of many tumors. Targeted therapies of this pathway have played important roles in the study of triple negative breast cancer (TNBC). Targeting the Hippo pathway in combination with chemotherapy or other targeted therapies has been shown to significantly improve specific antitumor effects and reduce cancer antidrug resistance. Further exploration has shown that the Hippo pathway is closely related to endocrine resistance, and it plays a "co-correlation point" role in numerous pathways involving endocrine resistance, including related pathways in breast cancer stem cells (BCSCs). Agents and miRNAs targeting the components of the Hippo pathway are expected to significantly enhance the sensitivity of breast cancer cells to endocrine therapy. This review initially explains the possible mechanism of the Hippo pathway in combating endocrine resistance, and it concludes by recommending endocrine therapy in combination with therapies targeting the Hippo pathway in the study of endocrine-resistant breast cancers.

Regulatory effect of microRNA-223-3p on breast cancer cell processes via the Hippo/Yap signaling pathway

According to the 2018 global cancer statistics, the incidence and mortality rates of breast cancer are increasing gradually, which seriously threatens the health of women. MicroRNA-223-3p (miR-223-3p) can promote the proliferation and invasion of breast cancer cells. Hippo/Yes-related protein (Yap) signaling pathway activation has been found in a variety of tumors. The present study aimed to investigate the potential mechanism of miR-223-3p in breast cancer. The Cell Counting Kit-8 assay was used to detect cell viability and flow cytometry was used to detect apoptosis. The abilities of cell migration and invasion were detected using scratch and Transwell assays, as well as reverse transcription-quantitative PCR and western blotting to detect gene and protein expression, respectively. The current results demonstrated that miR-223-3p transcription levels were increased in breast cancer cells, and inhibition of miR-223-3p gene expression decreased cell proliferation, migration and invasion. Additionally, inhibition of miR-223-3p expression inhibited epithelial-mesenchymal transition (EMT) in breast cancer cells. miR-223-3p promoted cell proliferation, migration, invasion and EMT, and the western blotting results demonstrated that miR-223-3p inhibition increased the phosphorylation of Yap1 and the protein expression levels of large tumor suppressor kinase 1. In conclusion, results from the present results suggested that miR-223-3p may promote cell proliferation, migration, invasion and EMT through the Hippo/Yap signaling pathway. Therefore, miR-223-3p may be a potential biomarker for breast cancer.

TEAD4 is a novel independent predictor of prognosis in LGG patients with IDH mutation

TEA domain family members (TEADs) play important roles in tumor progression. Till now, the genomic status of TEADs in patients with glioma has not been well investigated. To confirm whether the genomic status of TEADs could affect the prognosis of patients with glioma, the copy number variation (CNV), mutation and expression data of glioma cohorts in The Cancer Genome Atlas, Gene Expression Omnibus and Chinese Glioma Genome Atlas were comprehensively analyzed. Results showed that TEAD CNV frequency in lower grade gliomas (LGGs) was higher than in glioblastoma multiforme (GBM). Multivariate cox regression analysis showed that TEAD4 CNV increase was significantly associated with overall survival (OS) and disease-free survival (DFS) in LGGs (OS p = 0.022, HR = 1.444, 95% CI: 1.054–1.978; DFS p = 0.005, HR = 1.485, 95% CI: 1.124–1.962), while not in GBM. Patients with TEAD4 CNV increase showed higher expression level of TEAD4 gene. In LGG patients with IDH mutation, those with higher TEAD4 expression levels had shorter OS and DFS. Integrating TEAD4 CNV increase, IDH mutations, TP53 mutation, ATRX mutation and 1p19q co-deletion would separate patients with LGG into four groups with significant differences in prognosis. These study results suggested that TEAD4 variations were independent predictive biomarkers for the prognosis in patients with LGG with IDH mutation.

MicroRNAs Regulating Hippo-YAP Signaling in Liver Cancer

Liver cancer is one of the most common cancers worldwide, and its prevalence and mortality rate are increasing due to the lack of biomarkers and effective treatments. The Hippo signaling pathway has long been known to control liver size, and genetic depletion of Hippo kinases leads to liver cancer in mice through activation of the downstream effectors yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Both YAP and TAZ not only reprogram tumor cells but also alter the tumor microenvironment to exert carcinogenic effects. Therefore, understanding the mechanisms of YAP/TAZ-mediated liver tumorigenesis will help overcome liver cancer. For decades, small noncoding RNAs, microRNAs (miRNAs), have been reported to play critical roles in the pathogenesis of many cancers, including liver cancer. However, the interactions between miRNAs and Hippo-YAP/TAZ signaling in the liver are still largely unknown. Here, we review miRNAs that influence the proliferation, migration and apoptosis of tumor cells by modulating Hippo-YAP/TAZ signaling during hepatic tumorigenesis. Previous findings suggest that these miRNAs are potential biomarkers and therapeutic targets for the diagnosis, prognosis, and treatment of liver cancer.

Long Non-Coding RNA-PAICC Promotes the Tumorigenesis of Human Intrahepatic Cholangiocarcinoma by Increasing YAP1 Transcription

Intrahepatic cholangiocarcinoma (ICC) is a heterogeneous hepatobiliary tumor with poor prognosis, and it lacks reliable prognostic biomarkers and effective therapeutic targets. Long non-coding RNAs (lncRNAs) have been documented to be involved in the progression of various cancers. However, the role of lncRNAs in ICC remains largely unknown. In the present work, we used bioinformatics analysis to identify the differentially expressed lncRNAs in human ICC tissues, among which lncRNA-PAICC was found to be an independent prognostic marker in ICC. Moreover, lncRNA-PAICC promoted the proliferation and invasion of ICC cells. Mechanistically, lncRNA-PAICC acted as a competitive endogenous RNA (ceRNA) that directly sponged the tumor suppressive microRNAs miR-141-3p and miR-27a-3p. The competitive binding property was essential for lncRNA-PAICC to promote tumor growth and metastasis through activating the Hippo pathway. In summary, our results highlighted the important role of the lncRNA-PAICC-miR-141-3p/27a-3p-Yap1 axis in ICC, which offers a novel perspective on the molecular pathogenesis and may serve as a potential target for antimetastatic molecular therapies of ICC.

MiR-103a-3p promotes tumour glycolysis in colorectal cancer via hippo/YAP1/HIF1A axis

Background

Glycolysis plays an essential role in the growth and metastasis of solid cancer and has received increasing attention in recent years. However, the complex regulatory mechanisms of tumour glycolysis remain elusive. This study aimed to explore the molecular effect and mechanism of the noncoding RNA miR-103a-3p on glycolysis in colorectal cancer (CRC).

Methods

We explored the effects of miR-103a-3p on glycolysis and the biological functions of CRC cells in vitro and in vivo. Furthermore, we investigated whether miR-103a-3p regulates HIF1A expression through the Hippo/YAP1 pathway, and evaluated the role of the miR-103a-3p-LATS2/SAV1-YAP1-HIF1A axis in promoting glycolysis and angiogenesis in CRC cells and contributed to invasion and metastasis of CRC cells.

Results

We found that miR-103a-3p was highly expressed in CRC tissues and cell lines compared with matched controls and the high expression of miR-103a-3p was associated with poor patient prognosis. Under hypoxic conditions, a high level of miR-103a-3p promoted the proliferation, invasion, migration, angiogenesis and glycolysis of CRC cells. Moreover, miR-103a-3p knockdown inhibited the growth, proliferation, and glycolysis of CRC cells and promoted the Hippo-YAP1 signalling pathway in nude mice in a xenograft model. Here, we demonstrated that miR-103a-3p could directly target LATS2 and SAV1. Subsequently, we verified that TEAD1, a transcriptional coactivator of Yes-associated protein 1 (YAP1), directly bound to the HIF1A promoter region and the YAP1 and TEAD1 proteins co-regulated the expression of HIF1A, thus promoting tumour glycolysis.

Conclusions

MiR-103a-3p, which is highly expressed in CRC cells, promotes HIF1A expression by targeting the core molecules LATS2 and SAV1 of the Hippo/YAP1 pathway, contributing to enhanced proliferation, invasion, migration, glycolysis and angiogenesis in CRC. Our study revealed the functional mechanisms of miR-103a-3p/YAP1/HIF1A axis in CRC glycolysis, which would provide potential intervention targets for molecular targeted therapy of CRC.

Mechanical Cues Affect Migration and Invasion of Cells From Three Different Directions

Cell migration and invasion is a key driving factor for providing essential cellular functions under physiological conditions or the malignant progression of tumors following downward the metastatic cascade. Although there has been plentiful of molecules identified to support the migration and invasion of cells, the mechanical aspects have not yet been explored in a combined and systematic manner. In addition, the cellular environment has been classically and frequently assumed to be homogeneous for reasons of simplicity. However, motility assays have led to various models for migration covering only some aspects and supporting factors that in some cases also include mechanical factors. Instead of specific models, in this review, a more or less holistic model for cell motility in 3D is envisioned covering all these different aspects with a special emphasis on the mechanical cues from a biophysical perspective. After introducing the mechanical aspects of cell migration and invasion and presenting the heterogeneity of extracellular matrices, the three distinct directions of cell motility focusing on the mechanical aspects are presented. These three different directions are as follows: firstly, the commonly used invasion tests using structural and structure-based mechanical environmental signals; secondly, the mechano-invasion assay, in which cells are studied by mechanical forces to migrate and invade; and thirdly, cell mechanics, including cytoskeletal and nuclear mechanics, to influence cell migration and invasion. Since the interaction between the cell and the microenvironment is bi-directional in these assays, these should be accounted in migration and invasion approaches focusing on the mechanical aspects. Beyond this, there is also the interaction between the cytoskeleton of the cell and its other compartments, such as the cell nucleus. In specific, a three-element approach is presented for addressing the effect of mechanics on cell migration and invasion by including the effect of the mechano-phenotype of the cytoskeleton, nucleus and the cell's microenvironment into the analysis. In precise terms, the combination of these three research approaches including experimental techniques seems to be promising for revealing bi-directional impacts of mechanical alterations of the cellular microenvironment on cells and internal mechanical fluctuations or changes of cells on the surroundings. Finally, different approaches are discussed and thereby a model for the broad impact of mechanics on cell migration and invasion is evolved.

Downregulation of microRNA-224-3p Hampers Retinoblastoma Progression via Activation of the Hippo-YAP Signaling Pathway by Increasing LATS2

Purpose

The pivotal role of microRNAs (miRNAs or miRs) has been proved in the pathogenesis of retinoblastoma. miR-224-3p is demonstrated to be involved in several tumors. However, the underlying mechanism of miR-224-3p in retinoblastoma is yet to be investigated. Therefore, this study was designed to identify the regulation of miR-224-3p in human retinoblastoma.

Methods

The expression pattern of miR-224-3p and large tumor suppressor 2 (LATS2) in retinoblastoma was measured by reverse transcription quantitative polymerase chain reaction. Afterward, the interaction between miR-224-3p and LATS2 was identified using a dual luciferase reporter gene assay. Next, gain-of-function and loss-of-function approaches were employed to examine the effects of miR-224-3p and LATS2 as well as their interaction on cell apoptosis, proliferation and angiogenesis abilities, and tumorigenesis. Whether the Hippo-YAP signaling pathway was involved in tumorigenesis was analyzed by determining downstream genes.

Results

LATS2 was downregulated in retinoblastoma, and its overexpression promoted apoptosis and suppressed proliferation of retinoblastoma cells. miR-224-3p, highly expressed in retinoblastoma, inhibited the expression of its target gene LATS2, which inhibited activation of the Hippo-YAP signaling pathway. Suppression of miR-224-3p promoted apoptosis while suppressing the proliferation of retinoblastoma cells and angiogenesis. Tumor progression induced by upregulation of miR-224-3p was diminished by restoration of LATS2. It was observed that tumor growth and angiogenesis were reduced by depleted miR-224-3p in the animal experiments.

Conclusions

The present study suggests that miR-224-3p targets LATS2 and blocks the Hippo-YAP signaling pathway activation, thus preventing the progression of retinoblastoma, which could be a new therapeutic target for retinoblastoma.

Targeting Hippo signaling pathway by phytochemicals in cancer therapy

The current era of cancer research has been continuously advancing upon identifying novel aspects of tumorigenesis and the principal mechanisms behind the unleashed proliferation, invasion, drug resistance and immortality of cancer cells in hopes of exploiting these findings to achieve a more effective treatment for cancer. In pursuit of this goal, the identification of the first components of an extremely important regulatory pathway in Drosophila melanogaster that largely determines cell fate during the developmental stages, ended up in the discovery of the highly sophisticated Hippo signaling cascade. Soon after, it was revealed that deregulation of the components of this pathway either via mutations or through epigenetic alterations can be observed in a vast variety of tumors and these alterations greatly contribute to the neoplastic transformation of cells, their survival, growth and resistance to therapy. As more hidden aspects of this pathway such as its widespread entanglement with other major cellular signaling pathways are continuously being uncovered, many researchers have sought over the past decade to find ways of therapeutic interventions targeting the major components of the Hippo cascade. To date, various approaches such as the use of exogenous targeting miRNAs and different molecular inhibitors have been recruited herein, among which naturally occurring compounds have shown a great promise. On such a basis, in the present work we review the current understanding of Hippo pathway and the most recent evidence on targeting its components using natural plant-derived phytochemicals.

gga-microRNA-375 negatively regulates the cell cycle and proliferation by targeting Yes-associated protein 1 in DF-1 cells

MicroRNAs (miRNAs/miRs) serve a key role in regulating the cell cycle and inducing tumorigenesis. Subgroup J of the avian leukosis virus (ALV-J) belongs to the family Retroviridae, subfamily Orthoretrovirinae and genus Alpharetrovirus that causes tumors in susceptible chickens. gga-miR-375 is downregulated and Yes-associated protein 1 (YAP1) is upregulated in ALV-J-induced tumors in the livers of chickens, and it has been further identified that YAP1 is the direct target gene of gga-miR-375. In the present study, it was found that ALV-J infection promoted the cell cycle and proliferation in DF-1 cells. As the cell cycle and cell proliferation are closely associated with tumorigenesis, further experiments were performed to determine whether gga-miR-375 and YAP1 were involved in these cellular processes. It was demonstrated that gga-miR-375 significantly inhibited the cell cycle by inhibiting G₁ to S/G₂ stage transition and decreasing cell proliferation, while YAP1 significantly promoted the cell cycle and proliferation. Furthermore, these cellular processes in DF-1 cells were affected by gga-miR-375 through the targeting of YAP1. Collectively, the present results suggested that gga-miR-375, downregulated by ALV-J infection, negatively regulated the cell cycle and proliferation via the targeting of YAP1.

Mst1/2 kinases restrain transformation in a novel transgenic model of Ras driven non-small cell lung cancer

Non-small cell lung cancer remains a highly lethal malignancy. Using the tamoxifen inducible Hnf1b:CreERT2 (H) transgenic mouse crossed to the LsL-KrasG12D (K) transgenic mouse, we recently discovered that an Hnf1b positive cell type in the lung is sensitive to adenoma formation when expressing a mutant KrasG12D allele. In these mice, we observe adenoma formation over a time frame of three to six months. To study specificity of the inducible Hnf1b:CreERT2 in the lung, we employed lineage tracing using an mTmG (G) reporter allele. This technique revealed recombined, GFP+ cells were predominantly SPC+. We further employed this technique in HKG mice to determine Hnf1b+ cells give rise to adenomas that express SPC and TTF1. Review of murine lung tissue confirmed a diagnosis of adenoma and early adenocarcinoma, a pathologic subtype of non-small cell lung cancer. Our expanded mouse model revealed loss of Mst1/2 promotes aggressive lung adenocarcinoma and large-scale proteomic analysis revealed upregulation of PKM2 in the lungs of mice with genetic deletion of Mst1/2. PKM2 is a known metabolic regulator in proliferating cells and cancer. Using a human lung adenocarcinoma cell line, we show pharmacologic inhibition of Mst1/2 increases the abundance of PKM2, indicating genetic loss or pharmacologic inhibition of Mst1/2 directly modulates the abundance of PKM2. In conclusion, here we report a novel model of non-small cell lung cancer driven by a mutation in Kras and deletion of Mst1/2 kinases. Tumor development is restricted to a subset of alveolar type II cells expressing Hnf1b. Our data show loss of Mst1/2 regulates levels of a potent metabolic regulator, PKM2.

Fufang Xueshuantong protects retinal vascular endothelial cells from high glucose by targeting YAP

Fufang Xueshuantong (FXST), a Chinese patent medicine, is composed of Panax notoginseng, Salviae miltiorrhizae, Astragali Radix and Radix Scrophulariae and has been found to prevent diabetic retinopathy. Yes-associated protein (YAP) participates in the pathophysiology of retinal disease and promotes endothelial cell proliferation and angiogenesis. Although it is known that YAP activity is altered by FXST, the role of YAP in mediating the effect of FXST remains unclear. In high glucose-treated retinal vascular endothelial cells (RVECs), FXST significantly reduced cell viability, the number of migrating cells and tube length in the present study. Moreover, FXST decreased the levels of YAP mRNA and protein and inhibited the expression of vascular endothelial growth factor (VEGF). Transfection of sh-YAP into the cells decreased the ability of FXST to modulate cell migration and tube formation. The effect of FXST on VEGF expression was also decreased. Similar results were obtained when the cells were stimulated with a YAP inhibitor in combination with FXST. Thus, FXST is shown to protect high glucose-injured RVECs via YAP-mediated effects.

Down-regulation of interferon regulatory factor 2 binding protein 2 suppresses gastric cancer progression by negatively regulating connective tissue growth factor

Interferon regulatory factor 2 binding protein 2 (IRF2BP2) is a transcriptional repressor involved in regulating gene expression and other biological processes, including tumorigenesis. However, the clinical significance and roles of IRF2BP2 in human gastric cancer (GC) remain uncertain. Clinical GC tissues were obtained from GC patients at the First Affiliated Hospital of Nanchang University. Immunohistochemistry (IHC) was conducted to detect the IRF2BP2 protein in clinical paraffin specimens. Cell proliferation, migration and invasion were evaluated by MTT, colony formation assays and transwell assays. Co-immunoprecipitation was conducted to detect the interaction between TEA domain family members 4 (TEAD4) and vestigial-like family member 4 (VGLL4) or Yes-associated protein 1 (YAP1). Dual-luciferase reporter assay was used to confirm the binding of miR-101-3p to the 3'-UTR. The expression of IRF2BP2 was significantly higher in GC tissues than in normal tissues. Patients with higher IRF2BP2 protein expression had lower survival. IRF2BP2 knockdown inhibited proliferation, migration, invasion and epithelial-mesenchymal transition in GC cells. IRF2BP2 knockdown decreased the mRNA and protein levels of connective tissue growth factor (CTGF). The interaction between IRF2BP2 and VGLL4 increased the binding of TEAD4 to YAP1, resulting in the transcriptional coactivation of CTGF. In addition, miR-101-3p suppressed the expression of CTGF by directly targeting the 3'-UTR of IRF2BP2. Taken together, these findings provide a model for the role of miR-101-3p-IRF2BP2-CTGF signalling axis in GC and a novel insight into the mechanism of GC progression and metastasis.

Cell-intrinsic PD-1 promotes proliferation in pancreatic cancer by targeting CYR61/CTGF via the hippo pathway

Pancreatic ductal adenocarcinoma (PDAC) remains a refractory disease. Programmed cell death protein-1 (PD-1) monotherapy has shown strong performance in targeting several malignancies. However, the effect and mechanism of intrinsic PD-1 in pancreatic cancer cells is still unknown. In this study, associations between clinicopathological characteristics and stained tissue microarrays of PDAC specimens were analyzed along with profiling and functional analyses. The results showed that cell-intrinsic PD-1 was significantly correlated with overall survival (OS). Independently of adaptive immunity, intrinsic PD-1 promoted tumor growth in PDAC. Concomitantly, the overexpression of intrinsic PD-1 enhanced cancer proliferation and inhibited cell apoptosis in vitro and in vivo. Mechanistically, PD-1 binds to the downstream MOB1, thereby inhibiting its phosphorylation. Moreover, greater synergistic tumor suppression in vitro resulted from combining Hippo inhibitors with anti-PD-1 treatment compared with the suppression achieved by either single agent alone. Additionally, Hippo downstream targets, CYR61 (CCN1) and CTGF (CCN2), were directly affected by PD-1 mediated Hippo signaling activation in concert with survival outcomes. Finally, the formulated nomogram showed superior predictive accuracy for OS in comparison with the TNM stage alone. Therefore, PD-1 immunotherapy in combination with Hippo pathway inhibitors may optimize the anti-tumor efficacy in PDAC patients via targeting cell-intrinsic PD-1.

The antineoplastic drug metformin downregulates YAP by interfering with IRF-1 binding to the YAP promoter in NSCLC

Background

Activation of the oncogene YAP has been shown to be related to lung cancer progression and associates with poor prognosis and metastasis. Metformin is a drug commonly used in the treatment of diabetes and with anticancer activity. However, the mechanism through which metformin inhibits tumorigenesis via YAP is poorly understood.

Methods

The mRNA and protein expressions were analyzed by RT-PCR and western blot. The cellular proliferation was detected by CCK8 and MTT. The cell migration and invasion growth were analyzed by wound healing assay and transwell assay. The activities of promoter were analyzed by luciferase reporter assay. Chromatin immunoprecipitation detected the combining ability of IRF-1 and 5′UTR-YAP.

Findings

Our immunohistochemistry staining and RT-PCR assays showed that the expression of YAP was higher in lung carcinoma samples. Interestingly, metformin was able to downregulate YAP mRNA and protein expression in lung cancer cells. Mechanistically, we found that metformin depressed YAP promoter by competing with the binding of the transcription factor IRF-1 in lung cancer cells. Moreover, combination of metformin and verteporfin synergistically inhibits cell proliferation, promotes apoptosis and suppresses cell migration/invasion by downregulating YAP, therefore reduces the side effects caused by their single use and improve the quality of life for patients with lung cancer.

Interpretation

we concluded that metformin depresses YAP promoter by interfering with the binding of the transcription factor IRF-1. Importantly, verteporfin sensitizes metformin-induced the depression of YAP and inhibition of cell growth and invasion in lung cancer cells.

Fund

This work was supported by National Natural Science Foundation of China (No.31801085), the Science and Technology Development Foundation of Yantai (2015ZH082), Natural Science Foundation of Shandong Province (ZR2018QH004, ZR2016HB55, ZR2017PH067 and ZR2017MH125), and Research Foundation of Binzhou Medical University (BY2015KYQD29 and BY2015KJ14).

CircRNA-associated ceRNA network reveals ErbB and Hippo signaling pathways in hypopharyngeal cancer

Accumulating evidence has suggested that circular RNAs (circRNAs), a novel class of non-coding RNAs, have crucial roles in tumor progression. However, the significance of circRNAs in hypopharyngeal cancer (HCa) remains to be investigated. The present study has identified aberrantly expressed circRNAs by performing circRNA sequencing analyses of three pairs of tumor and adjacent normal samples from patients with HCa. The results demonstrated that 173 circRNAs were differentially expressed (DE), including 71 upregulated and 102 downregulated circRNAs (FDR<0.05 and fold changes of ≥2 or ≤0.5 by Mann-Whitney U test followed by Benjamini-Hochberg correction for multiple testing). Pathway analyses of the genes producing DE circRNAs revealed that many of them were involved in cancer-related pathways. To further illustrate the roles of circRNAs in HCa progression, a competing endogenous RNA (ceRNAs) network was constructed, consisting of circRNAs, miRNA, and miRNA targeted genes. The results demonstrated that multiple cancer-related pathways were affected by performing enrichment analyses of the targeted genes. Of note, a ceRNA subnetwork was isolated, consisting of two circRNAs (hsa_circ_0008287 and hsa_circ_0005027) and one miRNA (hsa-miR-548c-3p), which significantly affect both ErbB and Hippo signaling pathways. In conclusion, the present study identified a set of circRNAs that are potentially implicated in the tumorigenesis of HCa and may serve as potential biomarkers for the diagnosis of HCa.

TNFAIP8 promotes cell growth by regulating the Hippo pathway in epithelial ovarian cancer

Tumor necrosis factor-α-induced protein 8 (TNFAIP8) is an independent prognostic factor for cancer-specific and disease-free survival in patients with epithelial ovarian cancer (EOC). However, the exact mechanism of the biological role of TNFAIP8 in EOC remains unclear. In the present study, a siRNA specifically targeting TNFAIP8 was prepared to knock down TNFAIP8 in EOC cells. Cell growth, colony formation, apoptosis, and cell cycle distribution in TNFAIP8-deficient EOC cells were determined. In addition, the underlying molecular mechanisms were investigated by western blot analysis and reverse transcription quantitative polymerase chain reaction assays. It was demonstrated that the knockdown of TNFAIP8 inhibited EOC cell growth and colony formation, along with increased levels of apoptosis and cell cycle arrest. The results of the western blot analysis suggested that TNFAIP8 inhibited the expression of phosphorylated yes-associated protein 1 (YAP) while promoting total and nuclear YAP expression, followed by the regulation of apoptosis and cell cycle checkpoint protein expression in EOC. Overexpression of YAP in EOC cells efficiently attenuated cell growth inhibition in TNFAIP8-deficient EOC cells. In addition, knockdown of TNFAIP8 significantly impaired EOC tumor growth in vivo. Collectively, the data from the present study suggested that TNFAIP8 is an oncogene and a novel therapeutic target for EOC.

Co-existence of endometriosis with 13 non-gynecological co-morbidities: Mutation analysis by whole exome sequencing

Endometriosis is an enigmatic condition with an unknown etiology and poorly understood pathogenesis and women with endometriosis represent a high-risk population group for a large category of chronic conditions. The study focused on a 67-year-old woman who presented with a 40-year history of familial endometriosis associated with various non-gynecological co-morbidities, thus representing a unique case from a cohort of 1,000 patients with endometriosis. Her family history included infertile members suffering from endometriosis. Thirteen non-gynecological co-morbidities were documented throughout the years, including five autoimmune diseases (i.e., systemic lupus erythematosus, ankylosing spondylitis, multiple sclerosis, bronchial asthma and Crohn's disease), urinary bladder diverticulum, osteoporosis, multinodular goiter, cardiovascular diseases, gastroesophageal reflux disease, malignant tumor of urinary bladder, Barrett's esophagus and bilateral cataract. In order to understand the potential role of gene mutations in the development of all those co-morbidities, whole exome sequencing was performed and the presence of various disease-associated, potentially causal missense variants, were observed. These findings are in accordance with the previously suggested common underlying etiologic pathway for some, but not all, autoimmune disorders. This unusual case provides novel insights demonstrating that endometriosis can coexist with various chronic autoimmune diseases and other conditions, including non-gynecological malignancies, which possibly share a common genetic cause, a fact that should be taken into consideration seriously by clinicians.