Role of the Hippo pathway and mechanisms for controlling cellular localization of YAP/TAZ

Inhibition of neddylation disturbs zygotic genome activation through histone modification change and leads to early development arrest in mouse embryos

Post-translational modification and fine-tuned protein turnover are of great importance in mammalian early embryo development. Apart from the classic protein degradation promoting ubiquitination, new forms of ubiquitination-like modification are yet to be fully understood. Here, we demonstrate the function and potential mechanisms of one ubiquitination-like modification, neddylation, in mouse preimplantation embryo development. Treated with specific inhibitors, zygotes showed a dramatically decreased cleavage rate and almost all failed to enter the 4-cell stage. Transcriptional profiling showed genes were differentially expressed in pathways involving cell fate determination and cell differentiation, including several down-regulated zygotic genome activation (ZGA) marker genes. A decreased level of phosphorylated RNA polymerase II was detected, indicating impaired gene transcription inside the embryo cell nucleus. Proteomic data showed that differentially expressed proteins were enriched in histone modifications. We confirmed the lowered in methyltransferase (KMT2D) expression and a decrease in histone H3K4me3. At the same time, acetyltransferase (CBP/p300) reduced, while deacetylase (HDAC6) increased, resulting in an attenuation in histone H3K27ac. Additionally, we observed the up-regulation in YAP1 and RPL13 activities, indicating potential abnormalities in the downstream response of Hippo signaling pathway. In summary, we found that inhibition of neddylation induced epigenetic changes in early embryos and led to abnormalities in related downstream signaling pathways. This study sheds light upon new forms of ubiquitination regulating mammalian embryonic development and may contribute to further investigation of female infertility pathology.

Retinoic acid-induced protein 14 links mechanical forces to Hippo signaling

Cells sense and respond to various mechanical forces from the extracellular matrix primarily by modulating the actin cytoskeleton. Mechanical forces can be translated into biochemical signals in a process called mechanotransduction. Yes-associated protein (YAP) is an effector of Hippo signaling and a mediator of mechanotransduction, but how mechanical forces regulate Hippo signaling is still an open question. We propose that retinoic acid-induced protein 14 (RAI14) responds to mechanical forces and regulates Hippo signaling. RAI14 positively regulates the activity of YAP. RAI14 interacts with NF2, a key component of the Hippo pathway, and the interaction occurs on filamentous actin. When mechanical forces are kept low in cells, NF2 dissociates from RAI14 and filamentous actin, resulting in increased interactions with LATS1 and activation of the Hippo pathway. Clinical data show that tissue stiffness and expression of RAI14 and YAP are upregulated in tumor tissues and that RAI14 is strongly associated with adverse outcome in patients with gastric cancer. Our data suggest that RAI14 links mechanotransduction with Hippo signaling and mediates Hippo-related biological functions such as cancer progression.

Investigating underlying molecular mechanisms, signaling pathways, emerging therapeutic approaches in pancreatic cancer

Pancreatic adenocarcinoma, a clinically challenging malignancy constitutes a significant contributor to cancer-related mortality, characterized by an inherently poor prognosis. This review aims to provide a comprehensive understanding of pancreatic adenocarcinoma by examining its multifaceted etiologies, including genetic mutations and environmental factors. The review explains the complex molecular mechanisms underlying its pathogenesis and summarizes current therapeutic strategies, including surgery, chemotherapy, and emerging modalities such as immunotherapy. Critical molecular pathways driving pancreatic cancer development, including KRAS, Notch, and Hedgehog, are discussed. Current therapeutic strategies, including surgery, chemotherapy, and radiation, are discussed, with an emphasis on their limitations, particularly in terms of postoperative relapse. Promising research areas, including liquid biopsies, personalized medicine, and gene editing, are explored, demonstrating the significant potential for enhancing diagnosis and treatment. While immunotherapy presents promising prospects, it faces challenges related to immune evasion mechanisms. Emerging research directions, encompassing liquid biopsies, personalized medicine, CRISPR/Cas9 genome editing, and computational intelligence applications, hold promise for refining diagnostic approaches and therapeutic interventions. By integrating insights from genetic, molecular, and clinical research, innovative strategies that improve patient outcomes can be developed. Ongoing research in these emerging fields holds significant promise for advancing the diagnosis and treatment of this formidable malignancy.

YAP/TAZ, beta-catenin, and TGFb pathway activation in medical plasma-induced wound healing in diabetic mice

INTRODUCTION

Hippo is a signaling pathway that is evolutionarily conserved and plays critical roles in wound healing and tissue regeneration. Disruption of the transcriptional activity of both Hippo-associated factors, the yes-associated protein (YAP), and the transcriptional co-activator with PDZ binding motif (TAZ) has been associated with cardiovascular diseases, fibrosis, and cancer. This makes the Hippo pathway an appealing target for therapeutic interventions.

OBJECTIVES

Prior research has indicated that medical gas plasma promotes wound healing by delivering a combination of reactive species directly to the affected areas. However, the involvement of YAP/TAZ and other signaling pathways in diabetic wound healing remains unexplored.

METHODS

To this extent, ear wounds were generated and treated with gas plasma in streptozotocin (STZ)-induced diabetic mice. Transcriptome profiling at two wound healing stages (days 9 and 20 post-wounding) was performed in female and male mice. Additionally, we employed gene and protein expression analyses, utilizing immunohistological and -chemical staining of various targets as well as quantitative PCR and Western blot analysis.

RESULTS

Gas plasma treatment accelerated healing by increasing re-epithelialization and modifying extracellular matrix components. Transcriptomic profiling charting the major alterations in gene expression following plasma treatment was followed by a validation of several targets using transcriptional and translational quantification as well as localization analyses.

CONCLUSION

Our study evaluated the cellular regulation of essential targets of the Hippo and related pathways such as YAP/TAZ, β-catenin, tumor growth factor β, and oxidative stress signaling after plasma treatment. The activation of genes, pathways, and their regulators is an attractive therapeutic aim for a therapeutic intervention in dermal skin repair in diabetic diseases using medical gas plasmas.

Direct and selective pharmacological disruption of the YAP-TEAD interface by IAG933 inhibits Hippo-dependent and RAS-MAPK-altered cancers

The YAP-TEAD protein-protein interaction mediates YAP oncogenic functions downstream of the Hippo pathway. To date, available YAP-TEAD pharmacologic agents bind into the lipid pocket of TEAD, targeting the interaction indirectly via allosteric changes. However, the consequences of a direct pharmacological disruption of the interface between YAP and TEADs remain largely unexplored. Here, we present IAG933 and its analogs as potent first-in-class and selective disruptors of the YAP-TEAD protein-protein interaction with suitable properties to enter clinical trials. Pharmacologic abrogation of the interaction with all four TEAD paralogs resulted in YAP eviction from chromatin and reduced Hippo-mediated transcription and induction of cell death. In vivo, deep tumor regression was observed in Hippo-driven mesothelioma xenografts at tolerated doses in animal models as well as in Hippo-altered cancer models outside mesothelioma. Importantly this also extended to larger tumor indications, such as lung, pancreatic and colorectal cancer, in combination with RTK, KRAS-mutant selective and MAPK inhibitors, leading to more efficacious and durable responses. Clinical evaluation of IAG933 is underway.

Characterization of tumor endothelial cells (TEC) in gastric cancer and development of a TEC-based risk signature using single-cell RNA-seq and bulk RNA-seq data

BACKGROUND

Tumor endothelial cells (TECs) are essential participants in tumorigenesis. This study is focused on elucidating the TEC traits in gastric cancer (GC) and constructing a prognostic risk model to predict the clinical outcome of GC patients.

METHODS

Single-cell RNA sequencing (scRNA-seq) data were obtained from the GEO database. Using specific markers, the Seurat R package aided in processing scRNA-seq data and identifying TEC clusters. Based on TEC cluster-associated genes identified by Pearson correlation analysis, TEC-related prognostic genes were screened by lasso-Cox regression analysis, thereby constructing a risk signature. A nomogram was created by combining the risk signature with clinicopathological features.

RESULTS

Based on the scRNA-seq data, 5 TEC clusters were discovered in GC, with 3 of them showing prognostic associations in GC. A total of 163 genes were pinpointed among 3302 DEGs as significantly linked to TEC clusters, leading to the formulation of a risk signature comprising 8 genes. Furthermore, there was a notable correlation between the risk signature and the immune cell infiltration. Multivariate analysis findings indicated that the risk signature served as an independent prognostic factor for GC. Moreover, its efficacy in forecasting immune response was validated.

CONCLUSION

TEC-based risk model is highly effective in predicting the survival outcomes of GC patients and can forecast the immune response. Targeting TECs may significantly inhibit tumor progression and enhance the efficacy of immunotherapy.

TAZ deficiency exacerbates psoriatic pathogenesis by increasing the histamine-releasing factor

BACKGROUND

Transcriptional coactivator with PDZ-biding motif (TAZ) is widely expressed in most tissues and interacts with several transcription factors to regulate cell proliferation, differentiation, and death, thereby influencing organ development and size control. However, very little is known about the function of TAZ in the immune system and its association with inflammatory skin diseases, so we investigated the role of TAZ in the pathogenesis of psoriasis.

RESULTS

Interestingly, TAZ was expressed in mast cells associated, particularly in lysosomes, and co-localized with histamine-releasing factor (HRF). TAZ deficiency promoted mast cell maturation and increased HRF expression and secretion by mast cells. The upregulation of HRF in TAZ deficiency was not due to increased transcription but to protein stabilization, and TAZ restoration into TAZ-deficient cells reduced HRF protein. Interestingly, imiquimod (IMQ)-induced psoriasis, in which HRF serves as a major pro-inflammatory factor, was more severe in TAZ KO mice than in WT control. HRF expression and secretion were increased by IMQ treatment and were more pronounced in TAZ KO mice treated with IMQ.

CONCLUSIONS

Thus, as HRF expression was stabilized in TAZ KO mice, psoriatic pathogenesis progressed more rapidly, indicating that TAZ plays an important role in preventing psoriasis by regulating HRF protein stability.

VC-resist glioblastoma cell state: vessel co-option as a key driver of chemoradiation resistance

Glioblastoma (GBM) is a highly lethal type of cancer. GBM recurrence following chemoradiation is typically attributed to the regrowth of invasive and resistant cells. Therefore, there is a pressing need to gain a deeper understanding of the mechanisms underlying GBM resistance to chemoradiation and its ability to infiltrate. Using a combination of transcriptomic, proteomic, and phosphoproteomic analyses, longitudinal imaging, organotypic cultures, functional assays, animal studies, and clinical data analyses, we demonstrate that chemoradiation and brain vasculature induce cell transition to a functional state named VC-Resist (vessel co-opting and resistant cell state). This cell state is midway along the transcriptomic axis between proneural and mesenchymal GBM cells and is closer to the AC/MES1-like state. VC-Resist GBM cells are highly vessel co-opting, allowing significant infiltration into the surrounding brain tissue and homing to the perivascular niche, which in turn induces even more VC-Resist transition. The molecular and functional characteristics of this FGFR1-YAP1-dependent GBM cell state, including resistance to DNA damage, enrichment in the G2M phase, and induction of senescence/stemness pathways, contribute to its enhanced resistance to chemoradiation. These findings demonstrate how vessel co-option, perivascular niche, and GBM cell plasticity jointly drive resistance to therapy during GBM recurrence.

Dinaciclib exerts a tumor-suppressing effect via β-catenin/YAP axis in pancreatic ductal adenocarcinoma

Dinaciclib, a cyclin-dependent kinase-5 (CDK5) inhibitor, has significant anti-tumor properties. However, the precise mechanism of dinaciclib requires further investigation. Herein, we investigated the anti-tumor functions and molecular basis of dinaciclib in pancreatic ductal adenocarcinoma (PDAC). PDAC and matched para-carcinoma specimens were collected from the patients who underwent radical resection. Immunohistochemistry was performed to assess CDK5 expression. Cell proliferation ability, migration, and invasion were measured using Cell Counting Kit-8, wound healing, and transwell assay, respectively. The cell cycle and apoptosis were assessed using flow cytometry. Gene expression was examined using RNA-seq and quantitative real-time PCR. Protein expression of proteins was measured by western blot analysis and immunofluorescence microscopy. Tumor-bearing mice were intraperitoneally injected with dinaciclib. CDK5 is highly expressed in PDAC. The expression level of CDK5 was significantly related to tumor size, T stage, and the American Joint Committee on Cancer stage. High CDK5 expression can predict poor survival in PDAC patients. In addition, the expression level of CDK5 might be an independent prognostic factor for PDAC patients. Dinaciclib inhibits the growth and motility of PDAC cells and induces apoptosis and cell cycle arrest in the G2/M phase. Mechanistically, dinaciclib down-regulated yes-associated protein (YAP) mRNA and protein expression by reducing β-catenin expression. Moreover, dinaciclib significantly inhibited PDAC cell growth in vivo . Our findings reveal a novel anti-tumor mechanism of dinaciclib in which it decreases YAP expression by down-regulating β-catenin at the transcriptional level rather than by activating Hippo pathway-mediated phosphorylation-dependent degradation.

An Injectable Composite Hydrogel of Verteporfin-Bonded Carboxymethyl Chitosan and Oxidized Sodium Alginate Facilitates Scarless Full-Thickness Skin Regeneration

Full-thickness skin defect has always been a major challenge in clinics due to fibrous hyperplasia in the repair process. Hydrogel composite dressings loaded with anti-fibrotic drugs have been considered as a promising strategy for scarless skin regeneration. In this work, a hydrogel composite (VP-CMCS-OSA) of carboxymethyl chitosan (CMCS) and oxidized sodium alginate (OSA), with loading anti-fibrotic drug verteporfin (VP), is developed based on two-step chemical reactions. Verteporfin is bonded with carboxymethyl chitosan through EDC/NHS treatment to form VP-CMCS, and then VP-CMCS is crosslinked with oxidized sodium alginate by Schiff base reaction to form VP-CMCS-OSA hydrogel. The characterization by SEM, FTIR, and UV-Vis shows the microstructure and chemical bonding of VP-CMCS-OSA. VP-CMCS-OSA hydrogel demonstrates the properties of high tissue adhesion, strong self-healing, and tensile ability. In the full-thickness skin defect model, the VP-CMCS-OSA composite hydrogels hasten wound healing due to the synergistic effects of hydrogels and verteporfin administration. The histological examination reveals the regular collagen arrangement and more skin appendages after VP-CMCS-OSA composite hydrogel treatment, indicating the full-thickness skin regeneration without potential scar formation. The outcomes suggest that the verteporfin-loaded composite hydrogel could be a potential method for scarless skin regeneration.

Great potential of renal progenitor cells in kidney: From the development to clinic

The mammalian renal organ represents a pinnacle of complexity, housing functional filtering units known as nephrons. During embryogenesis, the depletion of niches containing renal progenitor cells (RPCs) and the subsequent incapacity of adult kidneys to generate new nephrons have prompted the formulation of protocols aimed at isolating residual RPCs from mature kidneys and inducing their generation from diverse cell sources, notably pluripotent stem cells. Recent strides in the realm of regenerative medicine and the repair of tissues using stem cells have unveiled critical signaling pathways essential for the maintenance and generation of human RPCs in vitro. These findings have ushered in a new era for exploring novel strategies for renal protection. The present investigation delves into potential transcription factors and signaling cascades implicated in the realm of renal progenitor cells, focusing on their protection and differentiation. The discourse herein elucidates contemporary research endeavors dedicated to the acquisition of progenitor cells, offering crucial insights into the developmental mechanisms of these cells within the renal milieu and paving the way for the formulation of innovative treatment modalities.

The role of angiotensin II activation of yes-associated protein/PDZ-binding motif signaling in hypertensive cardiac and vascular remodeling

Vascular remodeling is the pathogenic basis of hypertension and end organ injury, and the proliferation of vascular smooth muscle cells (VSMCs) is central to vascular remodeling. Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) are key effectors of the Hippo pathway and crucial for controlling cell proliferation, apoptosis and differentiation. The present study investigated the role of YAP/TAZ in cardiac and vascular remodeling of angiotensin II-induced hypertension. Ang II induced YAP/TAZ activation in the heart and aorta, which was prevented by YAP/TAZ inhibitor verteporfin. Treatment with verteporfin significantly reduced Ang II-induced cardiac and vascular hypertrophy with a mild reduction in systolic blood pressure (SBP), verteporfin attenuated Ang II-induced cardiac and aortic fibrosis with the inhibition of transform growth factor (TGF)β/Smad2/3 fibrotic signaling and extracellular matrix collagen I deposition. Ang II induced Rho A, extracellular signal-regulated kinase 1/2 (ERK1/2) and YAP/TAZ activation in VSMCs, either Rho kinase inhibitor fasudil or ERK inhibitor PD98059 suppressed Ang II-induced YAP/TAZ activation, cell proliferation and fibrosis of VSMCs. Verteporfin also inhibited Ang II-induced VSMC proliferation and fibrotic TGFβ1/Smad2/3 pathway. These results demonstrate that Ang II activates YAP/TAZ via Rho kinase/ERK1/2 pathway in VSMCs, which may contribute to cardiac and vascular remodeling in hypertension. Our results suggest that YAP/TAZ plays a critical role in the pathogenesis of hypertension and end organ damage, and targeting the YAP/TAZ pathway may be a new strategy for the prevention and treatment of hypertension and cardiovascular diseases.

Vemurafenib induces senescence in acute myeloid leukemia and myelodysplastic syndrome by activating the HIPPO signaling pathway: implications for potential targeted therapy

BACKGROUND

The outcome of Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) remain dismal despite the development of treatment. Targeted therapy is gaining more and more attention in improving prognosis.

METHODS

Expression of BRAF was analyzed by RT-qPCR in AML and MDS patients. Cells viability treated by drugs was measured by CCK-8 assay. Network pharmacology and RNA-sequence were used to analyze the mechanism of drugs and verified in vitro and xenograft tumor model.

RESULTS

Here we showed that BRAF was overexpressed in AML and MDS patients, and correlated with poor prognosis. The BRAF inhibitor-Vemurafenib (VEM) could significantly induce senescence, proliferation inhibition and apoptosis in AML cells, which can be enhanced by Bortezomib (BOR). This inhibitory effect was also verified in CD34 + cells derived from AML patients. Mechanistically, we showed that VEM combined with BOR could turn on HIPPO signaling pathway, thereby inducing cellular senescence in AML cells and xenograft mouse.

CONCLUSIONS

Taken together, our findings demonstrate a significant upregulation of BRAF expression in AML and MDS patients, which is associated with unfavorable clinical outcomes. We also discovered that the BRAF inhibitor Vemurafenib induces cellular senescence through activation of the HIPPO signaling pathway. Analysis of BRAF expression holds promise as a prognostic indicator and potential therapeutic target for individuals with AML and MDS.

An updated review of YAP: A promising therapeutic target against cardiac aging?

The transcriptional co-activator Yes-associated protein (YAP) functions as a downstream effector of the Hippo signaling pathway and plays a crucial role in cardiomyocyte survival. In its non-phosphorylated activated state, YAP binds to transcription factors, activating the transcription of downstream target genes. It also regulates cell proliferation and survival by selectively binding to enhancers and activating target genes. However, the upregulation of the Hippo pathway in human heart failure inhibits cardiac regeneration and disrupts astrogenesis, thus preventing the nuclear translocation of YAP. Existing literature indicates that the Hippo/YAP axis contributes to inflammation and fibrosis, potentially playing a role in the development of cardiac, vascular and renal injuries. Moreover, it is a key mediator of myofibroblast differentiation and fibrosis in the infarcted heart. Given these insights, can we harness YAP's regenerative potential in a targeted manner? In this review, we provide a detailed discussion of the Hippo signaling pathway and consolidate concepts for the development and intervention of cardiac anti-aging drugs to leverage YAP signaling as a pivotal target.

Comprehensive split TEV based protein-protein interaction screening reveals TAOK2 as a key modulator of Hippo signalling to limit growth

The conserved Hippo signalling pathway plays a crucial role in tumour formation by limiting tissue growth and proliferation. At the core of this pathway are tumour suppressor kinases STK3/4 and LATS1/2, which limit the activity of the oncogene YAP1, the primary downstream effector. Here, we employed a split TEV-based protein-protein interaction screen to assess the physical interactions among 28 key Hippo pathway components and potential upstream modulators. This screen led us to the discovery of TAOK2 as pivotal modulator of Hippo signalling, as it binds to the pathway's core kinases, STK3/4 and LATS1/2, and leads to their phosphorylation. Specifically, our findings revealed that TAOK2 binds to and phosphorylates LATS1, resulting in the reduction of YAP1 phosphorylation and subsequent transcription of oncogenes. Consequently, this decrease led to a decrease in cell proliferation and migration. Interestingly, a correlation was observed between reduced TAOK2 expression and decreased patient survival time in certain types of human cancers, including lung and kidney cancer as well as glioma. Moreover, in cellular models corresponding to these cancer types the downregulation of TAOK2 by CRISPR inhibition led to reduced phosphorylation of LATS1 and increased proliferation rates, supporting TAOK2's role as tumour suppressor gene. By contrast, overexpression of TAOK2 in these cellular models lead to increased phospho-LATS1 but reduced cell proliferation. As TAOK2 is a druggable kinase, targeting TAOK2 could serve as an attractive pharmacological approach to modulate cell growth and potentially offer strategies for combating cancer.

Phase separation in chemical and mechanical signal transduction

Signal transduction enables cells to sense and respond to chemical and mechanical information in the extracellular environment. Recently, phase separation has emerged as a physical mechanism that can influence the spatial organization of signaling molecules and regulate downstream signaling. Although many molecular components of signaling pathways, including receptors, kinases, and transcription factors, have been observed to undergo phase separation, understanding the functional consequences of their phase separation in signal transduction remains an ongoing area of research. In this review, we will discuss recent studies investigating how cells potentially use phase separation to regulate different signaling pathways by initiating signaling, amplifying signaling, or inhibiting signaling. We will also discuss recent observations that suggest a role for phase separation in mechanosensing in the Hippo pathway and at focal adhesions.

New Insights into YAP/TAZ-TEAD-Mediated Gene Regulation and Biological Processes in Cancer

The Hippo pathway is conserved across species. Key mammalian Hippo pathway kinases, including MST1/2 and LATS1/2, inhibit cellular growth by inactivating the TEAD coactivators, YAP, and TAZ. Extensive research has illuminated the roles of Hippo signaling in cancer, development, and regeneration. Notably, dysregulation of Hippo pathway components not only contributes to tumor growth and metastasis, but also renders tumors resistant to therapies. This review delves into recent research on YAP/TAZ-TEAD-mediated gene regulation and biological processes in cancer. We focus on several key areas: newly identified molecular patterns of YAP/TAZ activation, emerging mechanisms that contribute to metastasis and cancer therapy resistance, unexpected roles in tumor suppression, and advances in therapeutic strategies targeting this pathway. Moreover, we provide an updated view of YAP/TAZ's biological functions, discuss ongoing controversies, and offer perspectives on specific debated topics in this rapidly evolving field.

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.

Nuclear Import and Export of YAP and TAZ

Yes-associated Protein (YAP) and its paralog Transcriptional Coactivator with PDZ-binding Motif (TAZ) are major regulators of gene transcription/expression, primarily controlled by the Hippo pathway and the cytoskeleton. Integrating an array of chemical and mechanical signals, they impact growth, differentiation, and regeneration. Accordingly, they also play key roles in tumorigenesis and metastasis formation. Their activity is primarily regulated by their localization, that is, Hippo pathway- and/or cytoskeleton-controlled cytosolic or nuclear sequestration. While many details of such prevailing retention models have been elucidated, much less is known about their actual nuclear traffic: import and export. Although their size is not far from the cutoff for passive diffusion through the nuclear pore complex (NPC), and they do not contain any classic nuclear localization (NLS) or nuclear export signal (NES), evidence has been accumulating that their shuttling involves mediated and thus regulatable/targetable processes. The aim of this review is to summarize emerging information/concepts about their nucleocytoplasmic shuttling, encompassing the relevant structural requirements (NLS, NES), nuclear transport receptors (NTRs, karyophererins), and NPC components, along with the potential transport mechanisms and their regulation. While dissecting retention vs. transport is often challenging, the emerging picture suggests that YAP/TAZ shuttles across the NPC via multiple, non-exclusive, mediated mechanisms, constituting a novel and intriguing facet of YAP/TAZ biology.

Multiomic prediction of therapeutic targets for human diseases associated with protein phase separation

The phenomenon of protein phase separation (PPS) underlies a wide range of cellular functions. Correspondingly, the dysregulation of the PPS process has been associated with numerous human diseases. To enable therapeutic interventions based on the regulation of this association, possible targets should be identified. For this purpose, we present an approach that combines the multiomic PandaOmics platform with the FuzDrop method to identify PPS-prone disease-associated proteins. Using this approach, we prioritize candidates with high PandaOmics and FuzDrop scores using a profiling method that accounts for a wide range of parameters relevant for disease mechanism and pharmacological intervention. We validate the differential phase separation behaviors of three predicted Alzheimer's disease targets (MARCKS, CAMKK2, and p62) in two cell models of this disease. Overall, the approach that we present generates a list of possible therapeutic targets for human diseases associated with the dysregulation of the PPS process.

Simvastatin Attenuates Glucocorticoid-Induced Human Trabecular Meshwork Cell Dysfunction via YAP/TAZ Inactivation

PURPOSE

Impairment of the trabecular meshwork (TM) is the principal cause of increased outflow resistance in the glaucomatous eye. Yes-associated protein (YAP) and transcriptional coactivator with PDZ binding motif (TAZ) are emerging as potential mediators of TM cell/tissue dysfunction. Furthermore, YAP/TAZ activity was recently found to be controlled by the mevalonate pathway in non-ocular cells. Clinically used statins block the mevalonate cascade and were shown to improve TM cell pathobiology; yet, the link to YAP/TAZ signaling was not investigated. In this study, we hypothesized that simvastatin attenuates glucocorticoid-induced human TM (HTM) cell dysfunction via YAP/TAZ inactivation.

METHODS

Primary HTM cells were seeded atop or encapsulated within bioengineered extracellular matrix (ECM) hydrogels. Dexamethasone was used to induce a pathologic phenotype in HTM cells in the absence or presence of simvastatin. Changes in YAP/TAZ activity, actin cytoskeletal organization, phospho-myosin light chain levels, hydrogel contraction/stiffness, and fibronectin deposition were assessed.

RESULTS

Simvastatin potently blocked pathologic YAP/TAZ nuclear localization/activity, actin stress fiber formation, and myosin light chain phosphorylation in HTM cells. Importantly, simvastatin co-treatment significantly attenuated dexamethasone-induced ECM contraction/stiffening and fibronectin mRNA and protein levels. Sequential treatment was similarly effective but did not match clinically-used Rho kinase inhibition.

CONCLUSIONS

YAP/TAZ inactivation with simvastatin attenuates HTM cell pathobiology in a tissue-mimetic ECM microenvironment. Our data may help explain the association of statin use with a reduced risk of developing glaucoma via indirect YAP/TAZ inhibition as a proposed regulatory mechanism.

Diesel exhaust particles inhibit lung branching morphogenesis via the YAP/TAZ pathway

Prenatal exposure to air pollution may associated with inhibition of lung development in the child, however the possible mechanism is unclear. We investigated the effects of traffic-related diesel exhaust particle (DEP) exposure on fetal lung branching morphogenesis and elucidate the possible mechanism. Ex vivo fetal lungs collected from ICR mice at an age of 11.5 embryonic (E) days were exposed to DEPs at 0 (control), 10, and 50 μg/mL and branching morphogenesis was measured for 3 days. Normal IMR-90 human fetal lung fibroblast cells were exposed to DEPs at 0 (control), 10, and 50 μg/mL for 24 h. We observed that DEP exposure significantly inhibited lung branching morphogenesis with reduced lung branching ratios and surface areas on day 3. RNA sequencing (RNA-Seq) showed that DEP increased the inflammatory response and impaired lung development-related gene expressions. DEPs significantly decreased Yes-associated protein (YAP), phosphorylated (p)-YAP, transcriptional coactivator with a PDZ-binding motif (TAZ), and p-TAZ in IMR-90 cells at 10 and 50 μg/mL. Treatment of fetal lungs with the YAP inhibitor, PFI-2, also demonstrated restricted lung branching development similar to that of DEP exposure, with a significantly decreased lung branching ratio on day 3. DEP exposure significantly decreased the lung branching modulators fibroblast growth factor receptor 2 (FGFR2), sex-determining region Y-box 2 (SOX2), and SOX9 in IMR-90 cells at 10 and 50 μg/mL. Fetal lung immunofluorescence staining showed that DEP decreased SOX2 expression in fibronectin⁺ fibroblasts. DEP exposure decreased the cellular senescence regulator, p-sirtuin 1 (SIRT1)/SIRT1 in IMR-90 cells, with RNA-Seq showing impaired telomere maintenance. DEP exposure impaired fetal lung growth during the pseudoglandular stage through dysregulating the Hippo signaling pathway, causing fibroblast lung branching restriction and early senescence. Prenatal exposure to traffic-related air pollution has adverse effects on fetal lung development.

The Molecular Mechanisms of Systemic Sclerosis-Associated Lung Fibrosis

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disorder that affects the connective tissues and has the highest mortality rate among the rheumatic diseases. One of the hallmarks of SSc is fibrosis, which may develop systemically, affecting the skin and virtually any visceral organ in the body. Fibrosis of the lungs leads to interstitial lung disease (ILD), which is currently the leading cause of death in SSc. The identification of effective treatments to stop or reverse lung fibrosis has been the main challenge in reducing SSc mortality and improving patient outcomes and quality of life. Thus, understanding the molecular mechanisms, altered pathways, and their potential interactions in SSc lung fibrosis is key to developing potential therapies. In this review, we discuss the diverse molecular mechanisms involved in SSc-related lung fibrosis to provide insights into the altered homeostasis state inherent to this fatal disease complication.

Janus-Inspired Core-Shell Structure Hydrogel Programmatically Releases Melatonin for Reconstruction of Postoperative Bone Tumor

At present, surgery is one of the main treatments for bone tumor. However, the risk of recurrence and the large area of bone defects after surgery pose a great challenge. Therefore, a Janus-inspired core-shell structure bone scaffold was designed to achieve the self-programmed release of melatonin at different concentrations, clearing the residual tumor cells at early stage after resection and promoting bone repair later. The layered differential load designs inspired by Janus laid the foundation for the differential release of melatonin, where sufficient melatonin inhibited tumor growth as low dose promoted osteogenesis. Then, the automatically programmed delivery of melatonin is achieved by the gradient degradation of the core-shell structure. In the material characterization, scanning electron microscopy revealed the core-shell structure. The drug release experiment and in vivo degradation experiment reflected the programmed differential release of melatonin. In the biological experiment part, in vivo and in vitro experiments not only confirmed the significant inhibitory effect of the core-shell hydrogel scaffold on tumor but also confirmed its positive effect on osteogenesis. Our Janus-inspired core-shell hydrogel scaffold provides a safe and efficient means to inhibit tumor recurrence and bone repair after bone tumor, and it also develops a new and efficient tool for differential and programmed release of other drugs.

Fluid shear stress induces cell migration via RhoA-YAP1-autophagy pathway in liver cancer stem cells

Fluid shear stress (FSS) regulates the metastasis of hepatocellular carcinoma (HCC), but the role of the RhoA-YAP1-autophagy pathway in HCC remains unclear. Due to the core role of liver cancer stem cells (LCSCs) in HCC metastasis and recurrence, we explored the RhoA-YAP1-autophagy pathway in LCSCs under FSS. Our results indicate that LCSCs have stronger proliferation and cell spheroidization abilities. FSS (1 dyn/cm²) upregulated the migration of LCSCs and autophagy protein markers, inducing LC3B aggregation and autophagosome formation in LCSCs. Mechanistically, FSS promoted YAP1 dephosphorylation and transport to the nucleus, which is mediated by RhoA, inducing autophagy. Finally, inhibition of autophagy suppressed cell migration in LCSCs under FSS. In conclusion, FSS promoted the migration of LCSCs via the RhoA-YAP1-autophagy pathway.

Hippo Signaling in the Ovary: Emerging Roles in Development, Fertility, and Disease

Emerging studies indicate that the Hippo pathway, a highly conserved pathway that regulates organ size control, plays an important role in governing ovarian physiology, fertility, and pathology. Specific to the ovary, the spatiotemporal expression of the major components of the Hippo signaling cascade are observed throughout the reproductive lifespan. Observations from multiple species begin to elucidate the functional diversity and molecular mechanisms of Hippo signaling in the ovary in addition to the identification of interactions with other signaling pathways and responses to various external stimuli. Hippo pathway components play important roles in follicle growth and activation, as well as steroidogenesis, by regulating several key biological processes through mechanisms of cell proliferation, migration, differentiation, and cell fate determination. Given the importance of these processes, dysregulation of the Hippo pathway contributes to loss of follicular homeostasis and reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and ovarian cancers. This review highlights what is currently known about the Hippo pathway core components in ovarian physiology, including ovarian development, follicle development, and oocyte maturation, while identifying areas for future research to better understand Hippo signaling as a multifunctional pathway in reproductive health and biology.

Caveolin-1 and Its Functional Peptide CSP7 Affect Silica-Induced Pulmonary Fibrosis by Regulating Fibroblast Glutaminolysis

Exposure to silica is a cause of pulmonary fibrosis disease termed silicosis, which leads to respiratory failure and ultimately death. However, what drives fibrosis is not fully elucidated and therapeutic options remain limited. Our previous RNA-sequencing analysis showed that the expression of caveolin-1 (CAV1) was downregulated in silica-inhaled mouse lung tissues. Here, we not only verified that CAV1 was decreased in silica-induced fibrotic mouse lung tissues in both messenger RNA and protein levels, but also found that CSP7, a functional peptide of CAV1, could attenuate pulmonary fibrosis in vivo. Further in vitro experiments revealed that CAV1 reduced the expression of Yes-associated protein 1(YAP1) and affected its nuclear translocation in fibroblasts. In addition, Glutaminase 1 (GLS1), a key regulator of glutaminolysis, was identified to be a downstream effector of YAP1. CAV1 could suppress the activity of YAP1 to decrease the transcription of GLS1, thereby inhibiting fibroblast activation. Taken together, our results demonstrated that CAV1 and its functional peptide CSP7 may be potential molecules or drugs for the prevention and intervention of silicosis.

The uniformity and stability of cellular mass density in mammalian cell culture

Cell dry mass is principally determined by the sum of biosynthesis and degradation. Measurable change in dry mass occurs on a time scale of hours. By contrast, cell volume can change in minutes by altering the osmotic conditions. How changes in dry mass and volume are coupled is a fundamental question in cell size control. If cell volume were proportional to cell dry mass during growth, the cell would always maintain the same cellular mass density, defined as cell dry mass dividing by cell volume. The accuracy and stability against perturbation of this proportionality has never been stringently tested. Normalized Raman Imaging (NoRI), can measure both protein and lipid dry mass density directly. Using this new technique, we have been able to investigate the stability of mass density in response to pharmaceutical and physiological perturbations in three cultured mammalian cell lines. We find a remarkably narrow mass density distribution within cells, that is, significantly tighter than the variability of mass or volume distribution. The measured mass density is independent of the cell cycle. We find that mass density can be modulated directly by extracellular osmolytes or by disruptions of the cytoskeleton. Yet, mass density is surprisingly resistant to pharmacological perturbations of protein synthesis or protein degradation, suggesting there must be some form of feedback control to maintain the homeostasis of mass density when mass is altered. By contrast, physiological perturbations such as starvation or senescence induce significant shifts in mass density. We have begun to shed light on how and why cell mass density remains fixed against some perturbations and yet is sensitive during transitions in physiological state.

Chromatin as a sensor of metabolic changes during early development

Cellular metabolism is a complex network of biochemical reactions fueling development with energy and biomass; however, it can also shape the cellular epigenome. Indeed, some intermediates of metabolic reactions exert a non-canonical function by acting as co-factors, substrates or inhibitors of chromatin modifying enzymes. Therefore, fluctuating availability of such molecules has the potential to regulate the epigenetic landscape. Thanks to this functional coupling, chromatin can act as a sensor of metabolic changes and thus impact cell fate. Growing evidence suggest that both metabolic and epigenetic reprogramming are crucial for ensuring a successful embryo development from the zygote until gastrulation. In this review, we provide an overview of the complex relationship between metabolism and epigenetics in regulating the early stages of mammalian embryo development. We report on recent breakthroughs in uncovering the non-canonical functions of metabolism especially when re-localized to the nucleus. In addition, we identify the challenges and outline future perspectives to advance the novel field of epi-metabolomics especially in the context of early development.

Targeting the Hippo/YAP/TAZ signalling pathway: Novel opportunities for therapeutic interventions into skin cancers

Skin cancers are by far the most frequently diagnosed human cancers. The closely related transcriptional co-regulator proteins YAP and TAZ (WWTR1) have emerged as important drivers of tumour initiation, progression and metastasis in melanoma and non-melanoma skin cancers. YAP/TAZ serve as an essential signalling hub by integrating signals from multiple upstream pathways. In this review, we summarize the roles of YAP/TAZ in skin physiology and tumorigenesis and discuss recent efforts of therapeutic interventions that target YAP/TAZ in in both preclinical and clinical settings, as well as their prospects for use as skin cancer treatments.

TAZ Regulates the Cisplatin Resistance of Epithelial Ovarian Cancer Cells via the ANGPTL4/SOX2 Axis

Objective

Epithelial ovarian cancer (EOC) is a fatal gynecological malignancy. This study explored the mechanism of TAZ in regulating drug sensitivity of cisplatin (DDP-)-resistant EOC cells through the ANGPTL4/SOX2 axis.

Methods

The A2780/DDP cells were prepared by stepwise progressive concentration method. The drug resistance and TAZ expression in EOC cells were determined. Drug sensitivity was measured after TAZ overexpression in A2780 cells and TAZ downregulation in A2780/DDP cells, respectively. The effects of TAZ knockdown on apoptosis rate, stemness, and cancer stem cell (CSC) marker (CD44, OCT4, and ALDH1A) levels in A2780/DDP and DDP-treated A2780/DDP cells were assessed. The binding of TAZ and ANGPTL4 was verified using ChIP-qPCR, and ANGPTL4 and SOX2 levels were determined. The effects of different combined treatments of TAZ, ANGPTL4, and SOX2 on drug sensitivity of A2780/DDP cells and DDP-treated A2780/DDP cells were evaluated.

Results

TAZ was upregulated in drug-resistant EOC cells. TAZ knockdown significantly increased the drug sensitivity of A2780/DDP cells, while TAZ overexpression markedly decreased the drug sensitivity of A2780 cells. TAZ silencing promoted apoptosis of drug-resistant EOC cells and inhibited cell stemness. TAZ targeted ANGPTL4 and TAZ silencing enhanced drug sensitivity of A2780/DDP cells by inhibiting ANGPTL4. ANGPTL4 overexpression elevated SOX2 expression, and SOX2 downregulation reduced the drug resistance and promoted the apoptosis of A2780/DDP cells.

Conclusion

TAZ regulates DDP sensitivity of drug-resistant EOC cells via the ANGPTL4/SOX2 axis.

The O-GlcNAcylation and its promotion to hepatocellular carcinoma

O-GlcNAcylation is a posttranslational modification that attaches O-linked β-N-acetylglucosamine (O-GlcNAc) to the serine and threonine residues of proteins. Such a glycosylation would alter the activities, stabilities, and interactions of target proteins that are functional in a wide range of biological processes and diseases. Accumulating evidence indicates that O-GlcNAcylation is tightly associated with hepatocellular carcinoma (HCC) in its onset, growth, invasion and metastasis, drug resistance, and stemness. Here we summarize the discoveries of the role of O-GlcNAcylation in HCC and its function mechanism, aiming to deepen our understanding of HCC pathology, generate more biomarkers for its diagnosis and prognosis, and offer novel molecular targets for its treatment.

Crosstalk between Hypoxia and Extracellular Matrix in the Tumor Microenvironment in Breast Cancer

Even though breast cancer is the most diagnosed cancer among women, treatments are not always successful in preventing its progression. Recent studies suggest that hypoxia and the extracellular matrix (ECM) are important in altering cell metabolism and tumor metastasis. Therefore, the aim of this review is to study the crosstalk between hypoxia and the ECM and to assess their impact on breast cancer progression. The findings indicate that hypoxic signaling engages multiple mechanisms that directly contribute to ECM remodeling, ultimately increasing breast cancer aggressiveness. Second, hypoxia and the ECM cooperate to alter different aspects of cell metabolism. They mutually enhance aerobic glycolysis through upregulation of glucose transport, glycolytic enzymes, and by regulating intracellular pH. Both alter lipid and amino acid metabolism by stimulating lipid and amino acid uptake and synthesis, thereby providing the tumor with additional energy for growth and metastasis. Third, YAP/TAZ signaling is not merely regulated by the tumor microenvironment and cell metabolism, but it also regulates it primarily through its target c-Myc. Taken together, this review provides a better understanding of the crosstalk between hypoxia and the ECM in breast cancer. Additionally, it points to a role for the YAP/TAZ mechanotransduction pathway as an important link between hypoxia and the ECM in the tumor microenvironment, driving breast cancer progression.

Irisin promotes the proliferation and tenogenic differentiation of rat tendon-derived stem/progenitor cells via activating YAP/TAZ

Tendinopathy is a common tendon disorder characterized by pain, swelling, and dysfunction. Current evidence has demonstrated that the depletion of stem cell pool and non-tenogenic differentiation of tendon-derived stem/progenitor cells (TSPCs) might account for the pathogenesis of tendinopathy. FNDC5/Irisin, as a novel exercise-induced myokine, is proved to be involved in the exercise-induced protective effects on musculoskeletal disorders. However, whether irisin can affect TSPCs fate is still unknown. To ascertain the roles of irisin on the proliferation and tenogenic differentiation of TSPCs, rat TSPCs were isolated and incubated with irisin. Cell viability, phenotypic changes, and related signaling pathways were evaluated by CCK-8 assay, colony formation assay, real-time PCR, Western blot, immunofluorescence, and proteasome activity assay. We found that irisin treatment increased the proliferative and colony-forming abilities, and promoted the tenogenic differentiation of TSPCs by upregulating the expression of YAP/TAZ. In conclusion, our work showed for the first time that irisin promotes the proliferation and tenogenic differentiation of rat TSPCs in vitro by activating YAP/TAZ, and the process was associated with a ubiquitin-proteasome proteolytic pathway. In conclusion, irisin and agents targeting YAP/TAZ may be promising therapeutic options for tendinopathy.

Rab40c regulates focal adhesions and PP6 activity by controlling ANKRD28 ubiquitylation

Rab40c is a SOCS box-containing protein which binds Cullin5 to form a ubiquitin E3 ligase complex (Rab40c/CRL5) to regulate protein ubiquitylation. However, the exact functions of Rab40c remain to be determined, and what proteins are the targets of Rab40c-Cullin5-mediated ubiquitylation in mammalian cells are unknown. Here we showed that in migrating MDA-MB-231 cells Rab40c regulates focal adhesion's number, size, and distribution. Mechanistically, we found that Rab40c binds the protein phosphatase 6 (PP6) complex and ubiquitylates one of its subunits, ankyrin repeat domain 28 (ANKRD28), thus leading to its lysosomal degradation. Furthermore, we identified that phosphorylation of FAK and MOB1 is decreased in Rab40c knock-out cells, which may contribute to focal adhesion site regulation by Rab40c. Thus, we propose a model where Rab40c/CRL5 regulates ANKRD28 ubiquitylation and degradation, leading to a decrease in PP6 activity, which ultimately affects FAK and Hippo pathway signaling to alter focal adhesion dynamics.

LncRNA MNX1-AS1: A novel oncogenic propellant in cancers

To date, recent studies have shown that long non-coding RNAs (lncRNAs) are key players in gene regulation processes involved in cancer pathogenesis. In general, Motor neuron and pancreas homeobox 1-antisense RNA1 (MNX1-AS1) is highly expressed in all cancers as reported so far and exerts oncogenic effects through different mechanisms. In this review, we comprehensively summarize the detailed mechanisms of potential functions of MNX1-AS1 in different cancer types as well as the latest knowledge highlighting the potential of MNX1-AS1 as a therapeutic target for cancer. Aberrant expression of MNX1-AS1 closely correlates with clinicopathological parameters. such as lymphatic metastasis, tumor size, tumor stage, OS and DFS. Thus, MNX1-AS1 can be used as a diagnostic and prognostic biomarker or even a therapeutic prognostic target. This article reviews its function, molecular mechanism and clinical prognosis in various malignancies.

On the nuclear pore complex and its emerging role in cellular mechanotransduction

The nuclear pore complex (NPC) is a large protein assembly that perforates the nuclear envelope and provides a sole gateway for traffic between the cytoplasm and the nucleus. The NPC controls the nucleocytoplasmic transport by selectively allowing cargoes such as proteins and mRNA to pass through its central channel, thereby playing a vital role in protecting the nuclear component and regulating gene expression and protein synthesis. The selective transport through the NPC originates from its exquisite molecular structure featuring a large scaffold and the intrinsically disordered central channel domain, but the exact mechanism underlying the selective transport remains elusive and is the subject of various, often conflicting, hypotheses. Moreover, recent studies have suggested a new role for the NPC as a mechanosensor, where the NPC changes its channel diameter depending on the nuclear envelope tension, altering the molecular transportability through this nanopore. In this mini-review, we summarize the current understandings of the selective nature of the NPC and discuss its emerging role in cellular mechanotransduction.

The Bumpy Road to Stem Cell Therapies: Rational Design of Surface Topographies to Dictate Stem Cell Mechanotransduction and Fate

Cells sense and respond to a variety of physical cues from their surrounding microenvironment, and these are interpreted through mechanotransductive processes to inform their behavior. These mechanisms have particular relevance to stem cells, where control of stem cell proliferation, potency, and differentiation is key to their successful application in regenerative medicine. It is increasingly recognized that surface micro- and nanotopographies influence stem cell behavior and may represent a powerful tool with which to direct the morphology and fate of stem cells. Current progress toward this goal has been driven by combined advances in fabrication technologies and cell biology. Here, the capacity to generate precisely defined micro- and nanoscale topographies has facilitated the studies that provide knowledge of the mechanotransducive processes that govern the cellular response as well as knowledge of the specific features that can drive cells toward a defined differentiation outcome. However, the path forward is not fully defined, and the "bumpy road" that lays ahead must be crossed before the full potential of these approaches can be fully exploited. This review focuses on the challenges and opportunities in applying micro- and nanotopographies to dictate stem cell fate for regenerative medicine. Here, key techniques used to produce topographic features are reviewed, such as photolithography, block copolymer lithography, electron beam lithography, nanoimprint lithography, soft lithography, scanning probe lithography, colloidal lithography, electrospinning, and surface roughening, alongside their advantages and disadvantages. The biological impacts of surface topographies are then discussed, including the current understanding of the mechanotransductive mechanisms by which these cues are interpreted by the cells, as well as the specific effects of surface topographies on cell differentiation and fate. Finally, considerations in translating these technologies and their future prospects are evaluated.

Targeting GPCRs and Their Signaling as a Therapeutic Option in Melanoma

Simple Summary

Sixteen G-protein-coupled receptors (GPCRs) have been involved in melanogenesis or melanomagenesis. Here, we review these GPCRs, their associated signaling, and therapies.

Abstract

G-protein-coupled receptors (GPCRs) serve prominent roles in melanocyte lineage physiology, with an impact at all stages of development, as well as on mature melanocyte functions. GPCR ligands are present in the skin and regulate melanocyte homeostasis, including pigmentation. The role of GPCRs in the regulation of pigmentation and, consequently, protection against external aggression, such as ultraviolet radiation, has long been established. However, evidence of new functions of GPCRs directly in melanomagenesis has been highlighted in recent years. GPCRs are coupled, through their intracellular domains, to heterotrimeric G-proteins, which induce cellular signaling through various pathways. Such signaling modulates numerous essential cellular processes that occur during melanomagenesis, including proliferation and migration. GPCR-associated signaling in melanoma can be activated by the binding of paracrine factors to their receptors or directly by activating mutations. In this review, we present melanoma-associated alterations of GPCRs and their downstream signaling and discuss the various preclinical models used to evaluate new therapeutic approaches against GPCR activity in melanoma. Recent striking advances in our understanding of the structure, function, and regulation of GPCRs will undoubtedly broaden melanoma treatment options in the future.