ABSTRACT
The mevalonate pathway plays an important role in breast cancer and other tumor types. However, many issues remain obscure as yet regarding its mechanism of regulation and action. In the present study, we report that the expression of mevalonate pathway enzymes is mediated by the RHO guanosine nucleotide exchange factors VAV2 and VAV3 in a RAC1- and sterol regulatory element-binding factor (SREBF)-dependent manner in breast cancer cells. Furthermore, in vivo tumorigenesis experiments indicated that the two most upstream steps of this metabolic pathway [3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR)] are important for primary tumorigenesis, angiogenesis, and cell survival in breast cancer cells. HMGCR, but not HMGCS1, is also important for the extravasation and subsequent fitness of breast cancer cells in the lung parenchyma. Genome-wide expression analyses revealed that HMGCR influences the expression of gene signatures linked to proliferation, metabolism, and immune responses. The HMGCR-regulated gene signature predicts long-term tumor recurrence but not metastasis in cohorts of nonsegregated and chemotherapy-resistant breast cancer patients. These results reveal a hitherto unknown, VAV-catalysis-dependent mechanism involved in the regulation of the mevalonate pathway in breast cancer cells. They also identify specific mevalonate-pathway-dependent processes that contribute to the malignant features of breast cancer cells.
ABSTRACT
In developing brains, axons exhibit remarkable precision in selecting synaptic partners among many non-partner cells. Evolutionarily conserved teneurins are transmembrane proteins that instruct synaptic partner matching. However, how intracellular signaling pathways execute teneurins' functions is unclear. Here, we use in situ proximity labeling to obtain the intracellular interactome of a teneurin (Ten-m) in the Drosophila brain. Genetic interaction studies using quantitative partner matching assays in both olfactory receptor neurons (ORNs) and projection neurons (PNs) reveal a common pathway: Ten-m binds to and negatively regulates a RhoGAP, thus activating the Rac1 small GTPases to promote synaptic partner matching. Developmental analyses with single-axon resolution identify the cellular mechanism of synaptic partner matching: Ten-m signaling promotes local F-actin levels and stabilizes ORN axon branches that contact partner PN dendrites. Combining spatial proteomics and high-resolution phenotypic analyses, this study advanced our understanding of both cellular and molecular mechanisms of synaptic partner matching.
ABSTRACT
Metastatic cutaneous melanoma is a fatal skin cancer. Resistance to targeted and immune therapies limits the benefits of current treatments. Identifying and adding anti-resistance agents to current treatment protocols can potentially improve clinical responses. Myocardin-related transcription factor (MRTF) is a transcriptional coactivator whose activity is indirectly regulated by actin and the Rho family of GTPases. We previously demonstrated that development of BRAF inhibitor (BRAFi) resistance frequently activates the Rho/MRTF pathway in human and mouse BRAFV600E melanomas. In clinical trials, pretreatment with BRAFi reduces the benefit of immune therapies. We aimed to test the efficacy of concurrent treatment with our MRTF pathway inhibitor CCG-257081 and anti-PD1 in vivo and to examine its effects on the melanoma immune microenvironment. Because MRTF pathway activation upregulates the expression of immune checkpoint inhibitor genes/proteins, we asked whether CCG-257081 can improve the response to immune checkpoint blockade. CCG-257081 reduced the expression of PDL1 in BRAFi-resistant melanoma cells and decreased surface PDL1 levels on both BRAFi-sensitive and -resistant melanoma cells. Using our recently described murine vemurafenib-resistant melanoma model, we found that CCG-257081, in combination with anti-PD1 immune therapy, reduced tumor growth and increased survival. Moreover, anti-PD1/CCG-257081 co-treatment increased infiltration of CD8+ T cells and B cells into the tumor microenvironment and reduced tumor-associated macrophages. Here, we propose CCG-257081 as an anti-resistance and immune therapy-enhancing anti-melanoma agent.
Subject(s)
B7-H1 Antigen , Drug Resistance, Neoplasm , Immune Checkpoint Inhibitors , Melanoma , Proto-Oncogene Proteins B-raf , Skin Neoplasms , Tumor Microenvironment , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins B-raf/metabolism , Animals , Melanoma/drug therapy , Melanoma/metabolism , Melanoma/genetics , Melanoma/pathology , Mice , Humans , B7-H1 Antigen/antagonists & inhibitors , B7-H1 Antigen/metabolism , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , Skin Neoplasms/drug therapy , Skin Neoplasms/pathology , Skin Neoplasms/genetics , Skin Neoplasms/metabolism , Tumor Microenvironment/drug effects , Cell Line, Tumor , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/metabolism , Trans-Activators/metabolism , Trans-Activators/genetics , Female , Signal Transduction/drug effects , rho GTP-Binding Proteins/metabolismABSTRACT
For eukaryotic cells to heal wounds, respond to immune signals, or metastasize, they must migrate, often by adhering to extracellular matrix (ECM). Cells may also deposit ECM components, leaving behind a footprint that influences their crawling. Recent experiments showed that some epithelial cell lines on micropatterned adhesive stripes move persistently in regions they have previously crawled over, where footprints have been formed, but barely advance into unexplored regions, creating an oscillatory migration of increasing amplitude. Here, we explore through mathematical modeling how footprint deposition and cell responses to footprint combine to allow cells to develop oscillation and other complex migratory motions. We simulate cell crawling with a phase field model coupled to a biochemical model of cell polarity, assuming local contact with the deposited footprint activates Rac1, a protein that establishes the cell's front. Depending on footprint deposition rate and response to the footprint, cells on micropatterned lines can display many types of motility, including confined, oscillatory, and persistent motion. On two-dimensional (2D) substrates, we predict a transition between cells undergoing circular motion and cells developing an exploratory phenotype. Small quantitative changes in a cell's interaction with its footprint can completely alter exploration, allowing cells to tightly regulate their motion, leading to different motility phenotypes (confined vs. exploratory) in different cells when deposition or sensing is variable from cell to cell. Consistent with our computational predictions, we find in earlier experimental data evidence of cells undergoing both circular and exploratory motion.
Subject(s)
Cell Movement , Extracellular Matrix , Cell Movement/physiology , Extracellular Matrix/metabolism , Extracellular Matrix/physiology , rac1 GTP-Binding Protein/metabolism , Humans , Cell Polarity/physiology , Models, Biological , Animals , Cell Adhesion/physiology , Epithelial Cells/metabolism , Epithelial Cells/cytology , Epithelial Cells/physiologyABSTRACT
Mono-O-glycosylation of target proteins by bacterial toxins or effector proteins is a well-known mechanism by which bacteria interfere with essential functions of host cells. The respective glycosyltransferases are important virulence factors such as the Clostridioides difficile toxins A and B. Here, we describe two glycosyltransferases of Yersinia species that have a high sequence identity: YeGT from the zoonotic pathogen Yersinia enterocolitica and YkGT from the murine pathogen Yersinia kristensenii. We show that both modify Rho family proteins by attachment of GlcNAc at tyrosine residues (Tyr-34 in RhoA). Notably, the enzymes differed in their target protein specificity. While YeGT modified RhoA, B, and C, YkGT possessed a broader substrate spectrum and glycosylated not only Rho but also Rac and Cdc42 subfamily proteins. Mutagenesis studies indicated that residue 177 is important for this broader target spectrum. We determined the crystal structure of YeGT shortened by 16 residues N terminally (sYeGT) in the ligand-free state and bound to UDP, the product of substrate hydrolysis. The structure assigns sYeGT to the GT-A family. It shares high structural similarity to glycosyltransferase domains from toxins. We also demonstrated that the 16 most N-terminal residues of YeGT and YkGT are important for the mediated translocation into the host cell using the pore-forming protective antigen of anthrax toxin. Mediated introduction into HeLa cells or ectopic expression of YeGT and YkGT caused morphological changes and redistribution of the actin cytoskeleton. The data suggest that YeGT and YkGT are likely bacterial effectors belonging to the family of tyrosine glycosylating bacterial glycosyltransferases.
Subject(s)
Bacterial Proteins , Tyrosine , Yersinia , Glycosylation , Humans , Yersinia/metabolism , Yersinia/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Tyrosine/metabolism , Tyrosine/chemistry , Glycosyltransferases/metabolism , Glycosyltransferases/genetics , Glycosyltransferases/chemistry , rhoA GTP-Binding Protein/metabolism , Yersinia enterocolitica/metabolism , Yersinia enterocolitica/genetics , Animals , HeLa Cells , Mice , Crystallography, X-Ray , Yersinia Infections/metabolism , Yersinia Infections/microbiologyABSTRACT
Phosphoinositide 3-kinase (PI3K) beta (PI3Kß) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), G-protein coupled receptors, and Rho-family GTPases. The mechanism by which PI3Kß prioritizes interactions with various membrane-tethered signaling inputs, however, remains unclear. Previous experiments did not determine whether interactions with membrane-tethered proteins primarily control PI3Kß localization versus directly modulate lipid kinase activity. To address this gap in our knowledge, we established an assay to directly visualize how three distinct protein interactions regulate PI3Kß when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling PI3Kß membrane localization, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kß prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GßGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kß to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GßGγ or pY/Rac1(GTP), PI3Kß activity is dramatically enhanced beyond what can be explained by simply increasing membrane localization. Instead, PI3Kß is synergistically activated by pY/GßGγ and pY/Rac1 (GTP) through a mechanism consistent with allosteric regulation.
Subject(s)
Class I Phosphatidylinositol 3-Kinases , rac1 GTP-Binding Protein , rho GTP-Binding Proteins , Humans , GTP-Binding Protein beta Subunits/metabolism , GTP-Binding Protein beta Subunits/chemistry , GTP-Binding Protein gamma Subunits/metabolism , GTP-Binding Protein gamma Subunits/chemistry , GTP-Binding Protein gamma Subunits/genetics , Microscopy, Fluorescence , Phosphatidylinositol 3-Kinases/metabolism , Protein Binding , Receptor Protein-Tyrosine Kinases/metabolism , Receptor Protein-Tyrosine Kinases/chemistry , rho GTP-Binding Proteins/metabolism , rho GTP-Binding Proteins/chemistry , Signal Transduction , Class I Phosphatidylinositol 3-Kinases/chemistry , Class I Phosphatidylinositol 3-Kinases/metabolism , rac1 GTP-Binding Protein/chemistry , rac1 GTP-Binding Protein/metabolismABSTRACT
The clinical use of the DNA damaging anticancer drug doxorubicin (DOX) is limited by irreversible cardiotoxicity, which depends on the cumulative dose. The RAS-homologous (RHO) small GTPase RAC1 contributes to DOX-induced DNA damage formation and cardiotoxicity. However, the pathophysiological relevance of other RHO GTPases than RAC1 and different cardiac cell types (i.e., cardiomyocytes, non-cardiomyocytes) for DOX-triggered cardiac damage is unclear. Employing diverse in vitro and in vivo models, we comparatively investigated the level of DOX-induced DNA damage in cardiomyocytes versus non-cardiomyocytes (endothelial cells and fibroblasts), in the presence or absence of selected RHO GTPase inhibitors. Non-cardiomyocytes exhibited the highest number of DOX-induced DNA double-strand breaks (DSB), which were efficiently repaired in vitro. By contrast, rather low levels of DSB were formed in cardiomyocytes, which however remained largely unrepaired. Moreover, DOX-induced apoptosis was detected only in non-cardiomyocytes but not in cardiomyocytes. Pharmacological inhibitors of RAC1 and CDC42 most efficiently attenuated DOX-induced DNA damage in all cell types examined in vitro. Consistently, immunohistochemical analyses revealed that the RAC1 inhibitor NSC23766 and the pan-RHO GTPase inhibitor lovastatin reduced the level of DOX-induced residual DNA damage in both cardiomyocytes and non-cardiomyocytes in vivo. Overall, we conclude that endothelial cells, fibroblasts and cardiomyocytes contribute to the pathophysiology of DOX-induced cardiotoxicity, with RAC1- and CDC42-regulated signaling pathways being especially relevant for DOX-stimulated DSB formation and DNA damage response (DDR) activation. Hence, we suggest dual targeting of RAC1/CDC42-dependent mechanisms in multiple cardiac cell types to mitigate DNA damage-dependent cardiac injury evoked by DOX-based anticancer therapy.
Subject(s)
Aminoquinolines , Doxorubicin , Endothelial Cells , Fibroblasts , Myocytes, Cardiac , Pyrimidines , cdc42 GTP-Binding Protein , rac1 GTP-Binding Protein , rac1 GTP-Binding Protein/metabolism , rac1 GTP-Binding Protein/antagonists & inhibitors , rac1 GTP-Binding Protein/genetics , Animals , Myocytes, Cardiac/drug effects , Myocytes, Cardiac/pathology , Myocytes, Cardiac/metabolism , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/pathology , cdc42 GTP-Binding Protein/metabolism , Doxorubicin/toxicity , Doxorubicin/adverse effects , Endothelial Cells/drug effects , Endothelial Cells/pathology , Endothelial Cells/metabolism , Cardiotoxicity , Antibiotics, Antineoplastic/toxicity , Mice , Apoptosis/drug effects , Male , Humans , Mice, Inbred C57BL , DNA Breaks, Double-Stranded/drug effects , Neuropeptides/metabolism , DNA Damage/drug effects , Cells, CulturedABSTRACT
Attachment of circulating tumor cells to the endothelial cells (ECs) lining blood vessels is a critical step in cancer metastatic colonization, which leads to metastatic outgrowth. Breast and prostate cancers are common malignancies in women and men, respectively. Here, we observe that ß1-integrin is required for human prostate and breast cancer cell adhesion to ECs under shear-stress conditions in vitro and to lung blood vessel ECs in vivo. We identify IQGAP1 and neural Wiskott-Aldrich syndrome protein (NWASP) as regulators of ß1-integrin transcription and protein expression in prostate and breast cancer cells. IQGAP1 and NWASP depletion in cancer cells decreases adhesion to ECs in vitro and retention in the lung vasculature and metastatic lung nodule formation in vivo. Mechanistically, NWASP and IQGAP1 act downstream of Cdc42 to increase ß1-integrin expression both via extracellular signal-regulated kinase (ERK)/focal adhesion kinase signaling at the protein level and by myocardin-related transcription factor/serum response factor (SRF) transcriptionally. Our results identify IQGAP1 and NWASP as potential therapeutic targets to reduce early metastatic dissemination.
Subject(s)
Integrin beta1 , Neoplasm Metastasis , Serum Response Factor , ras GTPase-Activating Proteins , Humans , Integrin beta1/metabolism , Integrin beta1/genetics , ras GTPase-Activating Proteins/metabolism , ras GTPase-Activating Proteins/genetics , Cell Line, Tumor , Serum Response Factor/metabolism , Male , Female , Prostatic Neoplasms/pathology , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/genetics , Animals , Trans-Activators/metabolism , Cell Adhesion , Wiskott-Aldrich Syndrome Protein, Neuronal/metabolism , Wiskott-Aldrich Syndrome Protein, Neuronal/genetics , Breast Neoplasms/pathology , Breast Neoplasms/metabolism , Breast Neoplasms/genetics , Mice , Focal Adhesion Kinase 1/metabolism , Focal Adhesion Kinase 1/genetics , Gene Expression Regulation, Neoplastic , cdc42 GTP-Binding Protein/metabolismABSTRACT
BACKGROUND: Lymphangiogenesis, the formation of lymphatic vessels, is tightly linked to the development of the venous vasculature, both at the cellular and molecular levels. Here, we identify a novel role for Sorbs1, the founding member of the SoHo family of cytoskeleton adaptor proteins, in vascular and lymphatic development in the zebrafish. RESULTS: We show that Sorbs1 is required for secondary sprouting and emergence of several vascular structures specifically derived from the axial vein. Most notably, formation of the precursor parachordal lymphatic structures is affected in sorbs1 mutant embryos, severely impacting the establishment of the trunk lymphatic vessel network. Interestingly, we show that Sorbs1 interacts with the BMP pathway and could function outside of Vegfc signaling. Mechanistically, Sorbs1 controls FAK/Src signaling and subsequently impacts on the cytoskeleton processes regulated by Rac1 and RhoA GTPases. Inactivation of Sorbs1 altered cell-extracellular matrix (ECM) contacts rearrangement and cytoskeleton dynamics, leading to specific defects in endothelial cell migratory and adhesive properties. CONCLUSIONS: Overall, using in vitro and in vivo assays, we identify Sorbs1 as an important regulator of venous and lymphatic angiogenesis independently of the Vegfc signaling axis. These results provide a better understanding of the complexity found within context-specific vascular and lymphatic development.
Subject(s)
Lymphatic Vessels , Zebrafish , Animals , Zebrafish/genetics , Zebrafish/metabolism , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism , Lymphatic Vessels/metabolism , Lymphangiogenesis/physiology , Adaptor Proteins, Signal Transducing/metabolism , Cytoskeleton/metabolismABSTRACT
RhoU and RhoV are members of the Rho family of small GTPases that comprise their own subfamily. RhoUV GTPases are classified as atypical due to the kinetics of their GTP/GDP binding cycles. They also possess unique N- and C-termini that regulate their subcellular localization and activity. RhoU and RhoV have been linked to cytoskeletal regulation, cell adhesion, and cell migration. They each exhibit distinct expression patterns during embryonic development and diseases such as cancer metastasis, suggesting they have specialized functions. In this review, we will discuss the known functions of RhoU and RhoV, with a focus on their roles in early development, organogenesis, and disease.
Subject(s)
GTP-Binding Proteins , rho GTP-Binding Proteins , GTP-Binding Proteins/metabolism , rho GTP-Binding Proteins/metabolism , Signal Transduction , Cell AdhesionABSTRACT
VAV2 is an activator of RHO GTPases that promotes and maintains regenerative proliferation-like states in normal keratinocytes and oral squamous cell carcinoma (OSCC) cells. Here, we demonstrate that VAV2 also regulates ribosome biogenesis in those cells, a program associated with poor prognosis of human papilloma virus-negative (HPV-) OSCC patients. Mechanistically, VAV2 regulates this process in a catalysis-dependent manner using a conserved pathway comprising the RAC1 and RHOA GTPases, the PAK and ROCK family kinases, and the c-MYC and YAP/TAZ transcription factors. This pathway directly promotes RNA polymerase I activity and synthesis of 47S pre-rRNA precursors. This process is further consolidated by the upregulation of ribosome biogenesis factors and the acquisition of the YAP/TAZ-dependent undifferentiated cell state. Finally, we show that RNA polymerase I is a therapeutic Achilles' heel for both keratinocytes and OSCC patient-derived cells endowed with high VAV2 catalytic activity. Collectively, these findings highlight the therapeutic potential of modulating VAV2 and the ribosome biogenesis pathways in both preneoplastic and late progression stages of OSCC.
Subject(s)
Carcinoma, Squamous Cell , Head and Neck Neoplasms , Mouth Neoplasms , Proto-Oncogene Proteins c-vav , Humans , Carcinoma, Squamous Cell/pathology , Cell Proliferation , Keratinocytes/metabolism , Mouth Neoplasms/genetics , Mouth Neoplasms/metabolism , Proto-Oncogene Proteins c-vav/metabolism , rho GTP-Binding Proteins/metabolism , RNA Polymerase I/metabolism , Squamous Cell Carcinoma of Head and NeckABSTRACT
Clostridioides difficile causes life-threatening diarrhea and is one of the leading causes of nosocomial infections. During infection, C. difficile releases two gut-damaging toxins, TcdA and TcdB, which are the primary determinants of disease pathogenesis and are important therapeutic targets. Once in the cytosol of mammalian cells, TcdA and TcdB use UDP-glucose to glucosylate host Rho GTPases, which leads to cytoskeletal changes that result in a loss of intestinal integrity. Isofagomine inhibits TcdA and TcdB as a mimic of the glucocation transition state of the glucosyltransferase reaction. However, sequence variants of TcdA and TcdB across the clades of infective C. difficile continue to be identified, and therefore, evaluation of isofagomine inhibition against multiple toxin variants is required. Here, we show that isofagomine inhibits the glucosyltransferase domain of multiple TcdB variants and protects TcdB-induced cell rounding of the most common full-length toxin variants. Furthermore, we demonstrate that isofagomine protects against C. difficile-induced mortality in two murine models of C. difficile infection. Isofagomine treatment of mouse C. difficile infection also permitted the recovery of the gastrointestinal microbiota, an important barrier to preventing recurring C. difficile infection. The broad specificity of isofagomine supports its potential as a prophylactic to protect against C. difficile-induced morbidity and mortality.
Subject(s)
Bacterial Toxins , Boron Compounds , Clostridioides difficile , Imino Pyranoses , Animals , Mice , Bacterial Toxins/genetics , Enterotoxins , Clostridioides difficile/genetics , Bacterial Proteins/genetics , Glucosyltransferases/genetics , MammalsABSTRACT
Anithiactin D (1), a 2-phenylthiazole class of natural products, was isolated from marine mudflat-derived actinomycetes Streptomyces sp. 10A085. The chemical structure of 1 was elucidated based on the interpretation of NMR and MS data. The absolute configuration of 1 was determined by comparing the experimental and calculated electronic circular dichroism (ECD) spectral data. Anithiactin D (1) significantly decreased cancer cell migration and invasion activities at a concentration of 5 µM via downregulation of the epithelial-to-mesenchymal transition (EMT) markers in A549, AGS, and Caco-2 cell lines. Moreover, 1 inhibited the activity of Rho GTPases, including Rac1 and RhoA in the A549 cell line, suppressed RhoA in AGS and Caco-2 cell lines, and decreased the mRNA expression levels of some matrix metalloproteinases (MMPs) in AGS and Caco-2 cell lines. Thus 1, which is a new entity of the 2-phenylthiazole class of natural products with a unique aniline-indole fused moiety, is a potent inhibitor of the motility of cancer cells.
Subject(s)
Neoplasms , Streptomyces , Humans , Cell Line, Tumor , Caco-2 Cells , Streptomyces/metabolism , A549 Cells , rho GTP-Binding Proteins/metabolism , Cell Movement , Epithelial-Mesenchymal TransitionABSTRACT
RhoU is an atypical member of the Rho family of small G-proteins, which has N- and C-terminal extensions compared to the classic Rho GTPases RhoA, Rac1 and Cdc42, and associates with membranes through C-terminal palmitoylation rather than prenylation. RhoU mRNA expression is upregulated in prostate cancer and is considered a marker for disease progression. Here, we show that RhoU overexpression in prostate cancer cells increases cell migration and invasion. To identify RhoU targets that contribute to its function, we found that RhoU homodimerizes in cells. We map the region involved in this interaction to the C-terminal extension and show that C-terminal palmitoylation is required for self-association. Expression of the isolated C-terminal extension reduces RhoU-induced activation of p21-activated kinases (PAKs), which are known downstream targets for RhoU, and induces cell morphological changes consistent with inhibiting RhoU function. Our results show for the first time that the activity of a Rho family member is stimulated by self-association, and this is important for its activity.
Subject(s)
Prostatic Neoplasms , rho GTP-Binding Proteins , Humans , Male , cdc42 GTP-Binding Protein/genetics , cdc42 GTP-Binding Protein/metabolism , Cell Line, Tumor , Cell Movement/genetics , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , rho GTP-Binding Proteins/genetics , rho GTP-Binding Proteins/metabolismABSTRACT
Atypical Rho GTPases are a subtype of the Rho GTPase family that are involved in diverse cellular processes. The typical Rho GTPases, led by RhoA, Rac1 and Cdc42, have been well studied, while relative studies on atypical Rho GTPases are relatively still limited and have great exploration potential. With the increase in studies, current evidence suggests that atypical Rho GTPases regulate multiple biological processes and play important roles in the occurrence and development of human cancers. Therefore, this review mainly discusses the molecular basis of atypical Rho GTPases and their roles in cancer. We summarize the sequence characteristics, subcellular localization and biological functions of each atypical Rho GTPase. Moreover, we review the recent advances and potential mechanisms of atypical Rho GTPases in the development of multiple cancers. A comprehensive understanding and extensive exploration of the biological functions of atypical Rho GTPases and their molecular mechanisms in tumors will provide important insights into the pathophysiology of tumors and the development of cancer therapeutic strategies.
Subject(s)
Neoplasms , rho GTP-Binding Proteins , Humans , rho GTP-Binding Proteins/genetics , Neoplasms/geneticsABSTRACT
BACKGROUND: Emerging evidence suggests that Rho GTPases play a crucial role in tumorigenesis and metastasis, but their involvement in the tumor microenvironment (TME) and prognosis of hepatocellular carcinoma (HCC) is not well understood. METHODS: We aim to develop a tumor prognosis prediction system called the Rho GTPases-related gene score (RGPRG score) using Rho GTPase signaling genes and further bioinformatic analyses. RESULTS: Our work found that HCC patients with a high RGPRG score had significantly worse survival and increased immunosuppressive cell fractions compared to those with a low RGPRG score. Single-cell cohort analysis revealed an immune-active TME in patients with a low RGPRG score, with strengthened communication from T/NK cells to other cells through MIF signaling networks. Targeting these alterations in TME, the patients with high RGPRG score have worse immunotherapeutic outcomes and decreased survival time in the immunotherapy cohort. Moreover, the RGPRG score was found to be correlated with survival in 27 other cancers. In vitro experiments confirmed that knockdown of the key Rho GTPase-signaling biomarker SFN significantly inhibited HCC cell proliferation, invasion, and migration. CONCLUSIONS: This study provides new insight into the TME features and clinical use of Rho GTPase gene pattern at the bulk-seq and single-cell level, which may contribute to guiding personalized treatment and improving clinical outcome in HCC.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/genetics , Liver Neoplasms/genetics , Carcinogenesis , Cell Line , Immunosuppressive Agents , rho GTP-Binding Proteins , Tumor MicroenvironmentABSTRACT
Maintenance of cell junctions plays a crucial role in the regulation of cellular functions including cell proliferation, permeability, and cell death. Disruption of cell junctions is implicated in a variety of human disorders, such as inflammatory diseases and cancers. Understanding molecular regulation of cell junctions is important for development of therapeutic strategies for intervention of human diseases. Ubiquitination is an important type of post-translational modification that primarily regulates endogenous protein stability, receptor internalization, enzyme activity, and protein-protein interactions. Ubiquitination is tightly regulated by ubiquitin E3 ligases and can be reversed by deubiquitinating enzymes. Recent studies have been focusing on investigating the effect of protein stability in the regulation of cell-cell junctions. Ubiquitination and degradation of cadherins, claudins, and their interacting proteins are implicated in epithelial and endothelial barrier disruption. Recent studies have revealed that ubiquitination is involved in regulation of Rho GTPases' biological activities. Taken together these studies, ubiquitination plays a critical role in modulating cell junctions and motility. In this review, we will discuss the effects of ubiquitination and deubiquitination on protein stability and expression of key proteins in the cell-cell junctions, including junction proteins, their interacting proteins, and small Rho GTPases. We provide an overview of protein stability in modulation of epithelial and endothelial barrier integrity and introduce potential future search directions to better understand the effects of ubiquitination on human disorders caused by dysfunction of cell junctions.
Subject(s)
Animals , Humans , Inflammation , Metabolism , Pathology , Intercellular Junctions , Metabolism , Neoplasms , Metabolism , Pathology , Protein Stability , Ubiquitin-Protein Ligases , Metabolism , UbiquitinationABSTRACT
Las Rho GTPasas son una familia de proteínas que actúan como interruptores moleculares en diversas vías de señalización coordinando la regulación de distintos procesos celulares. La desregulación de dichas proteínas se vincula con transformación maligna y progresión tumoral en distintos tipos de cáncer. Por estos motivos, en los últimos años las Rho GTPasas fueron postuladas como blancos moleculares interesantes. En este trabajo describimos las distintas estrategias estudiadas utilizando a las Rho GTPasas como blanco y su grado de avance, mostrando una estrategia novedosa para el tratamiento del cáncer.
Rho GTPases are molecular switches that control the different cellular processes. Deregulation of these proteins is associated to transformation and malignant progression in several cancer types. Given the evidence available of the role of Rho GTPases in cancer it is suggested that these proteins can serve as potential therapeutic targets. This review focuses on the strategies used to develop Rho GTPases modulators and their potential use in therapeutic settings.
Subject(s)
Humans , rho GTP-Binding Proteins/antagonists & inhibitors , Molecular Targeted Therapy/methods , Neoplasms/drug therapy , Antineoplastic Agents/therapeutic use , rho GTP-Binding Proteins/physiology , Neoplasms/enzymologyABSTRACT
Objective The guanine exchange factors( GEFs) of Dbl family is a major regulatory unit for the malignant transformation of Rho family proteins. It plays a role by converting Rho protein from inactive GDP form to GTP form of Rho protein. In this paper,we discuss the structure and function of a GEF molecule-ARH-GEF 10,and discuss its role in the process of tumor development. Methods The expression of ARHGEF 10 in 42 normal tissues was measured by Real-Time PCR. GST-pulldown technique was used to detect the GEF ac-tivity of ARHGEF 10 in vivo. The transcription factor activity of downstream small molecules was detected by dual-luciferase report gene assay. The high expressive effect of ARHGEF 10 on normal cytoskeleton morphology was performed by dual immunofluorescence staining labeling method. High expressive effects of ARHGEF 10 on cell proliferation,invasion and tumorigenic ability in vitro were examined using CCK8,Transwell and soft agar clony formation assays. Results ARHGEF 10 has a typical GEFs structure,which binds to RhoA in vitro and promotes the proliferation and invasion of NIH3T3 cells,and has significant ability to clone in vitro. Conclusion ARH-GEF 10 is a typical family molecule of guanosine exchange factor that activates RhoA of Rho family,which has obvious oncogene characteristics.
ABSTRACT
Breast cancer is one of the major causes of death in women,and its incidence has been increasing year after year.The Rho GTPases,their regulatory proteins and Rho GTPases play an important role in promoting the occurrence and distant metastasis of breast cancer.Here we summarized the current knowledge of the regulation network of Rho GTPases,their regulatory proteins and Rho GTPases on the occurrence and development of breast cancer,and targeted therapy for RHO GTP enzyme pathway in breast cancer.