Rac-WAVE2 signaling is involved in the invasive and metastatic phenotypes of murine melanoma cells

The multiple functions and mechanisms of long non-coding RNAs in regulating breast cancer progression

Breast cancer (BC) is a malignant tumor that has the highest morbidity and mortality rates in the female population, and its high tendency to metastasize is the main cause of poor clinical prognosis. Long non-coding RNAs (lncRNAs) have been extensively documented to exhibit aberrant expression in various cancers and influence tumor progression via multiple molecular pathways. These lncRNAs not only modulate numerous aspects of gene expression in cancer cells, such as transcription, translation, and post-translational modifications, but also play a crucial role in the reprogramming of energy metabolism by regulating metabolic regulators, which is particularly significant in advanced BC. This review examines the characteristics and mechanisms of lncRNAs in regulating BC cells, both intracellularly (e.g., cell cycle, autophagy) and extracellularly (e.g., tumor microenvironment). Furthermore, we explore the potential of specific lncRNAs and their regulatory factors as molecular markers and therapeutic targets. Lastly, we summarize the application of lncRNAs in the treatment of advanced BC, aiming to offer novel personalized therapeutic options for patients.

Membrane Ruffles: Composition, Function, Formation and Visualization

Membrane ruffles are cell actin-based membrane protrusions that have distinct structural characteristics. Linear ruffles with columnar spike-like and veil-like structures assemble at the leading edge of cell membranes. Circular dorsal ruffles (CDRs) have no supporting columnar structures but their veil-like structures, connecting from end to end, present an enclosed ring-shaped circular outline. Membrane ruffles are involved in multiple cell functions such as cell motility, macropinocytosis, receptor internalization, fluid viscosity sensing in a two-dimensional culture environment, and protecting cells from death in response to physiologically compressive loads. Herein, we review the state-of-the-art knowledge on membrane ruffle structure and function, the growth factor-induced membrane ruffling process, and the growth factor-independent ruffling mode triggered by calcium and other stimulating factors, together with the respective underlying mechanisms. We also summarize the inhibitors used in ruffle formation studies and their specificity. In the last part, an overview is given of the various techniques in which the membrane ruffles have been visualized up to now.

Role of Wiskott Aldrich syndrome protein in haematological malignancies: genetics, molecular mechanisms and therapeutic strategies

As patients continue to suffer from lymphoproliferative and myeloproliferative diseases known as haematopoietic malignancies can affect the bone marrow, blood, lymph nodes, and lymphatic and non-lymphatic organs. Despite advances in the current treatment, there is still a significant challenge for physicians to improve the therapy of HMs. WASp is an important regulator of actin polymerization and the involvement of WASp in transcription is thought to be linked to the DNA damage response and repair. In some studies, severe immunodeficiency and lymphoid malignancy are caused by WASp mutations or the absence of WASp and these mutations in WAS can alter the function and/or expression of the intracellular protein. Loss-of-function and Gain-of-function mutations in WASp have an impact on cancer malignancies' incidence and onset. Recent studies suggest that depending on the clinical or experimental situation, WASPs and WAVEs can operate as a suppressor or enhancers for cancer malignancy. These dual functions of WASPs and WAVEs in cancer likely arose from their multifaceted role in cells that could be targeted for anticancer drug development. The significant role and their association of WASp in Chronic myeloid leukaemia, Juvenile myelomonocytic leukaemia and T-cell lymphoma is discussed. In this review, we described the structure and function of WASp and its family mechanism, analysing major regulatory effectors and summarising the clinical relevance and drugs that specifically target WASp in disease treatment in various hematopoietic malignancies by different approaches.

WAVE2 Is a Vital Regulator in Myogenic Differentiation of Progenitor Cells through the Mechanosensitive MRTFA-SRF Axis

Skeletal myogenesis is an intricate process involving the differentiation of progenitor cells into myofibers, which is regulated by actin cytoskeletal dynamics and myogenic transcription factors. Although recent studies have demonstrated the pivotal roles of actin-binding proteins (ABPs) as mechanosensors and signal transducers, the biological significance of WAVE2 (Wiskott-Aldrich syndrome protein family member 2), an ABP essential for actin polymerization, in myogenic differentiation of progenitor cells has not been investigated. Our study provides important insights into the regulatory roles played by WAVE2 in the myocardin-related transcription factor A (MRTFA)-serum response factor (SRF) signaling axis and differentiation of myoblasts. We demonstrate that WAVE2 expression is induced during myogenic differentiation and plays a pivotal role in actin cytoskeletal remodeling in C2C12 myoblasts. Knockdown of WAVE2 in C2C12 cells reduced filamentous actin levels, increased globular actin accumulation, and impaired the nuclear translocation of MRTFA. Furthermore, WAVE2 depletion in myoblasts inhibited the expression and transcriptional activity of SRF and suppressed cell proliferation in myoblasts. Consequently, WAVE2 knockdown suppressed myogenic regulatory factors (i.e., MyoD, MyoG, and SMYD1) expressions, thereby hindering the differentiation of myoblasts. Thus, this study suggests that WAVE2 is essential for myogenic differentiation of progenitor cells by modulating the mechanosensitive MRTFA-SRF axis.

LncIRF1 promotes chicken resistance to ALV-J infection

The pathogenesis of avian leukosis virus subgroup J (ALV-J) is complex and our understanding of it is limited. Based on our previous research, we explored the relationship between ALV-J infection and regulatory factor 1&7 (IRF1 and IRF7), interferon beta (IFNβ), and the newly identified long noncoding RNA IRF1 (LncIRF1). LncIRF1 is 1603 nt and exists in the cytoplasm and nucleus. After the occurrence of ALV-J infection, the expression levels of LncIRF1, IRF1, IRF7, and IFNβ varied in different chicken tissues. In DF1 cell lines of chicken embryo fibroblast cells (DF1 cells) the expression levels of LncIRF1, IRF7, IRF1, and IFNβ increased when ALV-J infection. Similarly, after LncIRF1 overexpression and the ALV-J challenge, the expression levels of IRF1, IRF7, and IFNβ increased, while increased LncIRF1 inhibited the proliferation of DF1 cells. Interference with LncIRF1 did not affect IRF1, IRF7, and IFNβ. However, expression levels of IRF1, IRF7, and IFNβ decreased due to LncIRF1 interference after the ALV-J challenge. An assay of the RNA-binding domain abundant in apicomplexans indicated that most of the proteins bound to LncIRF1 are related to cell proliferation and viral replication and these proteins also interact with IRF1, IRF7, and IFNβ. We suggest that LncIRF1 plays an important immunomodulatory role in the anti-ALV-J response.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03773-y.

Comprehensive pan-cancer investigation: unraveling the oncogenic, prognostic, and immunological significance of Abelson interactor family member 3 gene in human malignancies

Background: Abelson interactor Family Member 3 (ABI3) encodes protein that not only suppresses the ectopic metastasis of tumor cells but also hinders their migration. Although ABI3 had been found to modulate the advancement of diverse neoplasms, there is no comprehensive pan-cancer analysis of its effects. Methods: The transcriptomics data of neoplasm and normal tissues were retrieved from the Genomic Data Commons (GDC) data portal, and UCSC XENA database. To gather protein information for ABI3, Human Protein Atlas (HPA) and GeneMANIA websites were utilized. Additionally, Tumor Immune Single-cell Hub (TISCH) database was consulted to determine the primary cell types expressing ABI3 in cancer microenvironments. Univariate Cox regression approach was leveraged to evaluate ABI3's prognostic role across cancers. The Cbioportal and Gene Set Cancer Analysis (GSCA) website were leveraged to scrutinize the genomic landscape information across cancers. TIMER2.0 was leveraged to probe the immune cell infiltrations associated with ABI3 across cancers. The associations of ABI3 with immune-related genes were analyzed through Spearman correlation method. Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were utilized to search associated biological pathways. The CellMiner database and molecular docking were implemented to identify potential interactions between the ABI3 protein and specific anticarcinogen. Findings: ABI3 expression and its ability to predict prognosis varied distinct tumor, with particularly high expression observed in Tprolif cells and monocytes/macrophages. Copy number variation (CNV) and methylation negatively correlated with ABI3 expression in the majority of malignancies. Corresponding mutation survival analysis indicated that the mutation status of ABI3 was strongly connected to the prognosis of LGG patients. ABI3 expression was linked to immunotherapeutic biomarkers and response in cancers. ESTIMATE and immune infiltrations analyses presented ABI3 association with immunosuppression. ABI3 was significantly correlated with immunoregulators and immune-related pathways. Lastly, prospective ABI3-targeted drugs were filtered and docked to ABI3 protein. Interpretation: Our study reveals that ABI3 acts as a robust tumor biomarker. Its functions are vital that could inhibit ectopic metastasis of tumor cells and modulate cellular adhesion and migration. The discoveries presented here may have noteworthy consequences for the creation of fresh anticancer suppressors, especially those targeting BRCA.

Interaction between Rumen Epithelial miRNAs-Microbiota-Metabolites in Response to Cold-Season Nutritional Stress in Tibetan Sheep

Tibetan sheep are already well adapted to cold season nutrient stress on the Tibetan Plateau. Rumen, an important nutrient for metabolism and as an absorption organ in ruminants, plays a vital role in the cold stress adaptations of Tibetan sheep. Ruminal microbiota also plays an indispensable role in rumen function. In this study, combined multiomics data were utilized to comprehensively analyze the interaction mechanism between rumen epithelial miRNAs and microbiota and their metabolites in Tibetan sheep under nutrient stress in the cold season. A total of 949 miRNAs were identified in the rumen epithelium of both cold and warm seasons. A total of 62 differentially expressed (DE) miRNAs were screened using FC > 1.5 and p value < 0.01, and a total of 20,206 targeted genes were predicted by DE miRNAs. KEGG enrichment analysis revealed that DE miRNA-targeted genes were mainly enriched in axon guidance(ko04360), tight junction(ko04530), inflammatory mediator regulation of TRP channels(ko04750) and metabolism-related pathways. Correlation analysis revealed that rumen microbiota, rumen VFAs and DE miRNAs were all correlated. Further study revealed that the targeted genes of cold and warm season rumen epithelial DE miRNAs were coenriched with differential metabolites of microbiota in glycerophospholipid metabolism (ko00564), apoptosis (ko04210), inflammatory mediator regulation of TRP channels (ko04750), small cell lung cancer (ko05222), and choline metabolism in cancer (ko05231) pathways. There are several interactions between Tibetan sheep rumen epithelial miRNAs, rumen microbiota, and microbial metabolites, mainly through maintaining rumen epithelial barrier function and host homeostasis of choline and cholesterol, improving host immunity, and promoting energy metabolism pathways, thus enabling Tibetan sheep to effectively respond to cold season nutrient stress. The results also suggest that rumen microbiota have coevolved with their hosts to improve the adaptive capacity of Tibetan sheep to cold season nutrient stress, providing a new perspective for the study of cold season nutritional stress adaptation in Tibetan sheep.

Distinct shared and compartment-enriched oncogenic networks drive primary versus metastatic breast cancer

Metastatic breast-cancer is a major cause of death in women worldwide, yet the relationship between oncogenic drivers that promote metastatic versus primary cancer is still contentious. To elucidate this relationship in treatment-naive animals, we hereby describe mammary-specific transposon-mutagenesis screens in female mice together with loss-of-function Rb, which is frequently inactivated in breast-cancer. We report gene-centric common insertion-sites (gCIS) that are enriched in primary-tumors, in metastases or shared by both compartments. Shared-gCIS comprise a major MET-RAS network, whereas metastasis-gCIS form three additional hubs: Rho-signaling, Ubiquitination and RNA-processing. Pathway analysis of four clinical cohorts with paired primary-tumors and metastases reveals similar organization in human breast-cancer with subtype-specific shared-drivers (e.g. RB1-loss, TP53-loss, high MET, RAS, ER), primary-enriched (EGFR, TGFβ and STAT3) and metastasis-enriched (RHO, PI3K) oncogenic signaling. Inhibitors of RB1-deficiency or MET plus RHO-signaling cooperate to block cell migration and drive tumor cell-death. Thus, targeting shared- and metastasis- but not primary-enriched derivers offers a rational avenue to prevent metastatic breast-cancer.

Endocytosis in cancer and cancer therapy

Endocytosis is a complex process whereby cell surface proteins, lipids and fluid from the extracellular environment are packaged, sorted and internalized into cells. Endocytosis is also a mechanism of drug internalization into cells. There are multiple routes of endocytosis that determine the fate of molecules, from degradation in the lysosomes to recycling back to the plasma membrane. The overall rates of endocytosis and temporal regulation of molecules transiting through endocytic pathways are also intricately linked with signalling outcomes. This process relies on an array of factors, such as intrinsic amino acid motifs and post-translational modifications. Endocytosis is frequently disrupted in cancer. These disruptions lead to inappropriate retention of receptor tyrosine kinases on the tumour cell membrane, changes in the recycling of oncogenic molecules, defective signalling feedback loops and loss of cell polarity. In the past decade, endocytosis has emerged as a pivotal regulator of nutrient scavenging, response to and regulation of immune surveillance and tumour immune evasion, tumour metastasis and therapeutic drug delivery. This Review summarizes and integrates these advances into the understanding of endocytosis in cancer. The potential to regulate these pathways in the clinic to improve cancer therapy is also discussed.

The role of Raptor in lymphocytes differentiation and function

Raptor, a key component of mTORC1, is required for recruiting substrates to mTORC1 and contributing to its subcellular localization. Raptor has a highly conserved N-terminus domain and seven WD40 repeats, which interact with mTOR and other mTORC1-related proteins. mTORC1 participates in various cellular events and mediates differentiation and metabolism. Directly or indirectly, many factors mediate the differentiation and function of lymphocytes that is essential for immunity. In this review, we summarize the role of Raptor in lymphocytes differentiation and function, whereby Raptor mediates the secretion of cytokines to induce early lymphocyte metabolism, development, proliferation and migration. Additionally, Raptor regulates the function of lymphocytes by regulating their steady-state maintenance and activation.

Inhibition of cholesterol transport impairs Cav-1 trafficking and small extracellular vesicles secretion, promoting amphisome formation in melanoma cells

Caveolin-1 (Cav-1) is a fundamental constituent of caveolae, whose functionality and structure are strictly dependent on cholesterol. In this work the U18666A inhibitor was used to study the role of cholesterol transport in the endosomal degradative-secretory system in a metastatic human melanoma cell line (WM266-4). We found that U18666A induces a shift of Cav-1 from the plasma membrane to the endolysosomal compartment, which is involved, through Multi Vesicular Bodies (MVBs), in the formation and release of small extracellular vesicles (sEVs). Moreover, this inhibitor induces an increase in the production of sEVs with chemical-physical characteristics similar to control sEVs but with a different protein composition (lower expression of Cav-1 and increase of LC3II) and reduced transfer capacity on target cells. Furthermore, we determined that U18666A affects mitochondrial function and also cancer cell aggressive features, such as migration and invasion. Taken together, these results indicate that the blockage of cholesterol transport, determining the internalization of Cav-1, may modify sEVs secretory pathways through an increased fusion between autophagosomes and MVBs to form amphisome, which in turn fuses with the plasma membrane releasing a heterogeneous population of sEVs to maintain homeostasis and ensure correct cellular functionality.

FAT10 Induces cancer cell migration by stabilizing phosphorylated ABI3/NESH

The WAVE regulatory complex (WRC) is involved in various cellular processes by regulating actin polymerization. The dysregulation of WRC components is associated with cancer development. ABI family member 3 (ABI3)/new molecule including SH3 (NESH) is one of the WRC components and it has been reported that ABI3 phosphorylation can affect WRC function. Although several residues of ABI3 have been reported to be possible phosphorylation sites, it is still unclear which residues are important for the function of ABI3. Furthermore, it is unclear how the phosphorylated form of ABI3 is regulated. Here, we demonstrate that ABI3 is stabilized by its interaction with human leukocyte antigen-F adjacent transcript 10 (FAT10). Using phospho-dead or phospho-mimetic mutants of ABI3, we showed that serine 213 and 216 are important phosphorylation sites of ABI3. In particular, FAT10 has a higher affinity for the phosphorylated form of ABI3 than the non-phosphorylated form, and it stabilizes the phosphorylated form more than the non-phosphorylated form through this differential affinity. The interaction between FAT10 and the phosphorylated form of ABI3 promoted cancer cell migration. Therefore, our results suggest that FAT10 stabilizes the phosphorylated form of ABI3, which may lead to WRC activation, thereby promoting cancer cell migration.

SH3BP1 Regulates Melanoma Progression Through Race1/Wace2 Signaling Pathway

Background

SH3-domain binding protein-1 (SH3BP1), which specifically inactivates Rac1 and its target protein Wave2, has been shown to be an important regulator of cancer metastasis. However, the effects of SH3BP1 in melanoma progression remain unclear. The current study aimed to explore the function of SH3BP1 in melanoma and its possible molecular mechanism.

Methods

TCGA database was used to analyze the expression of SH3BP1 in melanoma. Then, reverse transcription-quantitative polymerase chain reaction was performed to detect the expression of SH3BP1 in melanoma tissues and cells. Next, genes related to SH3BP1 were analyzed by LinkedOmics database, and protein interactions were analyzed by STRING database. These genes were further subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. In addition, the signaling pathway of SH3BP1 action was screened by bioinformatics analysis. Finally, the function of SH3BP1 and its mediated signaling pathway in melanoma progression were investigated in vitro and in vivo.

Results

SH3BP1 was significantly upregulated in melanoma tissues and cells. The pathways regulated by SH3BP1 are closely related to the occurrence and development of tumors. And we found that overexpression of SH3BP1 promoted the proliferation, migration, and invasion of melanoma cells by increasing Rac1 activity and Wave2 protein levels in vitro. Similarly, overexpression of SH3BP1 facilitated melanoma progression by upregulating Wave2 protein expression in vivo.

Conclusion

In summary, this study revealed for the first time that SH3BP1 promoted melanoma progression through Rac1/Wave2 signaling pathway, providing a new therapeutic target for melanoma.

The Role of the Adapter Protein Anks1a in the Regulation of Breast Cancer Cell Motility

Epithelial-mesenchymal transition (EMT) is a critical step in tumor progression that leads to the acquisition by cancer cells the capacity for migration using the mesenchymal motility mode regulated by the Rac→WAVE→Arp2/3 signaling pathway. Earlier it was shown that proteins interacting with Rac can regulate mesenchymal migration and thus determine the metastatic potential of the cells. The search for new regulators of cell migration is an important theoretical and practical task. The adaptor protein Anks1a is one of the proteins interacting with Rac, whose expression is altered in many types of tumors. The aim of this study was to find whether Anks1a affects the migration of cancer cells and to identify the mechanism underlying this effect. It was suggested that Anks1a can influence cancer cell migration either as a Rac1 effector or by activating human epidermal growth factor receptor 2 (HER2) exchange. We investigated how upregulation and inhibition of Anks1a expression affected migration of breast cancer cells with different HER2 status. Anks1a was shown to interact with the activated form of Rac1. In the MDA-MB-231 cells (triple negative cancer), which lack HER2, Anks1a accumulated at the active cell edge, which is characterized by enrichment with active Rac1, whereas no such accumulation was observed in the HER2-overexpressing SK-BR-3 cells. Downregulation of the ANKS1a expression with esiRNA had almost no effect on the cancer cell motility, except a slight increase in the average migration rate of MDA-MB-231 cells. Among three cell lines tested, overexpression of Anks1a increased the migration rate of HER2-overexpressng SK-BR-3 cells only. We showed that Anks1a is an effector of activated Rac1, but its influence on the cell migration in this capacity was minimal, at least in the studied breast cancer cells. Anks1a affected the motility of breast cancer cells due to its involvement in the EGF receptor exchange.

Hypomethylation-mediated upregulation of the WASF2 promoter region correlates with poor clinical outcomes in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide. Wiskott–Aldrich syndrome protein family member 2 (WASF2) is an integral member of the actin cytoskeleton pathway, which plays a crucial role in cell motility. In this study, we aimed to explore the role of WASF2 in HCC carcinogenesis and its regulatory mechanism.

Methods

WASF2 expression in HCC was analyzed using six public RNA-seq datasets and 66 paired tissues from patients with HCC. The role of WASF2 in normal hepatocyte cell phenotypes was evaluated using a WASF2 overexpression vector in vitro; it was evaluated in HCC cell phenotypes using small interfering RNA (siRNA) in vitro and in vivo. Epigenetic regulatory mechanism of WASF2 was assessed in the Cancer Genome Atlas liver hepatocellular carcinoma project (TCGA_LIHC) dataset and also validated in 38 paired HCC tissues. Site mutagenesis, bisulfite sequencing polymerase chain reaction (BSP), methylation-specific polymerase chain reaction (MSP), and quantitative MSP (qMSP) were used for evaluating WASF2 methylation status.

Results

WASF2 is overexpressed in HCC and is clinically correlated with its prognosis. WASF2 overexpression promoted normal hepatocyte proliferation. WASF2 inactivation decreased the viability, growth, proliferation, migration, and invasion of Huh-7 and SNU475 HCC cells by inducing G2/M phase arrest. This induced cell death and inhibited epithelial–mesenchymal transition, hindering actin polymerization. In addition, WASF2 knockdown using siWASF2 in a xenograft mouse model and a lung metastasis model exerted tumor suppressive effect. There was a negative correlation between WASF2 methylation status and mRNA expression. The methylation pattern of CpG site 2 (− 726 bp), located in the WASF2 promoter, plays an important role in the regulation of WASF2 expression. Furthermore, the cg242579 CpG island in the WASF2 5′ promoter region was hypomethylated in HCC compared to that in the matched non-tumor samples. Patients with high WASF2 methylation and low WASF2 expression displayed the highest overall survival.

Conclusions

WASF2 is overexpressed and hypomethylated in HCC and correlates with patient prognosis. WASF2 inactivation exerts anti-tumorigenic effects on HCC cells in vitro and in vivo, suggesting that WASF2 could be a potential therapeutic target for HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02365-7.

EMX1 functions as a tumor inhibitor in spinal cord glioma through transcriptional suppression of WASF2 and inactivation of the Wnt/β-catenin axis

BACKGROUND

Gliomas are the most frequent and aggressive cancers in the central nervous system, and spinal cord glioma (SCG) is a rare class of the gliomas. Empty spiracles homobox genes (EMXs) have shown potential tumor suppressing roles in glioma, but the biological function of EMX1 in SCG is unclear.

METHODS

The EMX1 expression in clinical tissues of patients with SCG was examined. SCG cells were extracted from the tissues, and altered expression of EMX1 was then introduced to examine the role of EMX1 in cell growth and invasiveness in vitro. Xenograft tumors were induced in nude mice for in vivo validation. The targets of EXM1 were predicted via bioinformatic analysis and validated by luciferase and ChIP-qPCR assays. Rescue experiments were conducted to validate the involvements of the downstream molecules.

RESULTS

EMX1 was poorly expressed in glioma, which was linked to decreased survival rate of patients according to the bioinformatics prediction. In clinical tissues, EMX1 was poorly expressed in SCG, especially in the high-grade tissues. EMX1 upregulation significantly suppressed growth and metastasis of SCG cells in vitro and in vivo. EMX1 bound to the promoter of WASP family member 2 (WASF2) to suppress its transcription. Restoration of WASF2 blocked the tumor-suppressing effect of EMX1. EMX1 suppressed Wnt/β-catenin signaling activity by inhibiting WASF2. Coronaridine, a Wnt/β-catenin-specific antagonist, blocked SCG cell growth and metastasis induced by WASF2.

CONCLUSION

This study elucidates that EMX1 functions as a tumor inhibitor in SCG by suppressing WASF2-dependent activation of the Wnt/β-catenin axis.

WASF2 Serves as a Potential Biomarker and Therapeutic Target in Ovarian Cancer: A Pan-Cancer Analysis

Background

Wiskott-Aldrich syndrome protein family member 2 (WASF2) has been shown to play an important role in many types of cancer. Therefore, it is worthwhile to further study expression profile of WASF2 in human cancer, which provides new molecular clues about the pathogenesis of ovarian cancer.

Methods

We used a series of bioinformatics methods to comprehensively analyze the relationship between WASF2 and prognosis, tumor microenvironment (TME), immune infiltration, tumor mutational burden (TMB), microsatellite instability (MSI), and tried to find the potential biological processes of WASF2 in ovarian cancer. Biological behaviors of ovarian cancer cells were investigated through CCK8 assay, scratch test and transwell assay. We also compared WASF2 expression between epithelial ovarian cancer tissues and normal ovarian tissues by using immunohistochemical staining.

Results

In the present study, we found that WASF2 was abnormally expressed across the diverse cancer and significantly correlated with overall survival (OS) and progression-free interval (PFI). More importantly, the WASF2 expression level also significantly related to the TME. Our results also showed that the expression of WASF2 was closely related to immune infiltration and immune-related genes. In addition, WASF2 expression was associated with TMB, MSI, and antitumor drugs sensitivity across various cancer types. Functional bioinformatics analysis demonstrated that the WASF2 might be involved in several signaling pathways and biological processes of ovarian cancer. A risk factor model was found to be predictive for OS in ovarian cancer based on the expression of WASF2. Moreover, in vitro experiments, it was demonstrated that the proliferative, migratory and invasive capacity of ovarian cancer cells was significantly inhibited due to WASF2 knockdown. Finally, the immunohistochemistry data confirmed that WASF2 were highly expressed in ovarian cancer.

Conclusions

Our study demonstrated that WASF2 expression was associated with a poor prognosis and may be involved in the development of ovarian cancer, which might be explored as a potential prognostic marker and new targeted treatments.

RAC1 Activation as a Potential Therapeutic Option in Metastatic Cutaneous Melanoma

Metastasis is a complex process by which cancer cells escape from the primary tumor to colonize distant organs. RAC1 is a member of the RHO family of small guanosine triphosphatases that plays an important role in cancer migration, invasion, angiogenesis and metastasis. RAC1 activation has been related to most cancers, such as cutaneous melanoma, breast, lung, and pancreatic cancer. RAC1P29S driver mutation appears in a significant number of cutaneous melanoma cases. Likewise, RAC1 is overexpressed or hyperactivated via signaling through oncogenic cell surface receptors. Thus, targeting RAC1 represents a promising strategy for cutaneous melanoma therapy, as well as for inhibition of other signaling activation that promotes resistance to targeted therapies. In this review, we focus on the role of RAC1 in metastatic cutaneous melanoma emphasizing the anti-metastatic potential of RAC1- targeting drugs.

Targeting the actin nucleation promoting factor WASp provides a therapeutic approach for hematopoietic malignancies

Cancer cells depend on actin cytoskeleton rearrangement to carry out hallmark malignant functions including activation, proliferation, migration and invasiveness. Wiskott–Aldrich Syndrome protein (WASp) is an actin nucleation-promoting factor and is a key regulator of actin polymerization in hematopoietic cells. The involvement of WASp in malignancies is incompletely understood. Since WASp is exclusively expressed in hematopoietic cells, we performed in silico screening to identify small molecule compounds (SMCs) that bind WASp and promote its degradation. We describe here one such identified molecule; this WASp-targeting SMC inhibits key WASp-dependent actin processes in several types of hematopoietic malignancies in vitro and in vivo without affecting naïve healthy cells. This small molecule demonstrates limited toxicity and immunogenic effects, and thus, might serve as an effective strategy to treat specific hematopoietic malignancies in a safe and precisely targeted manner.

Cancer cells proliferate and invade via cytoskeletal proteins such as WASp, exclusively expressed in hematopoietic cells. Here the authors show a specific small molecule compound inhibiting cancer cell activity by WASp degradation and demonstrating its therapeutic potential in vitro and in vivo.

The Role of WAVE2 Signaling in Cancer

The Wiskott–Aldrich syndrome protein (WASP) and WASP family verprolin-homologous protein (WAVE)—WAVE1, WAVE2 and WAVE3 regulate rapid reorganization of cortical actin filaments and have been shown to form a key link between small GTPases and the actin cytoskeleton. Upon receiving upstream signals from Rho-family GTPases, the WASP and WAVE family proteins play a significant role in polymerization of actin cytoskeleton through activation of actin-related protein 2/3 complex (Arp2/3). The Arp2/3 complex, once activated, forms actin-based membrane protrusions essential for cell migration and cancer cell invasion. Thus, by activation of Arp2/3 complex, the WAVE and WASP family proteins, as part of the WAVE regulatory complex (WRC), have been shown to play a critical role in cancer cell invasion and metastasis, drawing significant research interest over recent years. Several studies have highlighted the potential for targeting the genes encoding either part of or a complete protein from the WASP/WAVE family as therapeutic strategies for preventing the invasion and metastasis of cancer cells. WAVE2 is well documented to be associated with the pathogenesis of several human cancers, including lung, liver, pancreatic, prostate, colorectal and breast cancer, as well as other hematologic malignancies. This review focuses mainly on the role of WAVE2 in the development, invasion and metastasis of different types of cancer. This review also summarizes the molecular mechanisms that regulate the activity of WAVE2, as well as those oncogenic pathways that are regulated by WAVE2 to promote the cancer phenotype. Finally, we discuss potential therapeutic strategies that target WAVE2 or the WAVE regulatory complex, aimed at preventing or inhibiting cancer invasion and metastasis.

Phosphorylation of the proline-rich domain of WAVE3 drives its oncogenic activity in breast cancer

Post-translational modification of proteins, such as tyrosine phosphorylation, plays a major role in driving the oncogenic activity of oncogenes. WAVE3 (WASF3), an adaptor and actin cytoskeleton remodeling protein, contributes to cell migration, cancer cell invasion, and metastasis. WAVE3 plays a vital role in the progression and metastasis of triple negative breast cancer (TNBC), in part through the regulation of cancer stem cells (CSCs). Several studies have shown that WAVE3 tyrosine phosphorylation is required for its oncogenic activity. Moreover, our recent study showed that the proline rich domain (PRD) of WAVE3 is required for maintenance of the CSC niche in breast cancer by regulating the nuclear translocation of the CSC-specific nuclear transcription factor YB1. Here, we show that the PRD domain of WAVE3 and its phosphorylation are essential for driving the oncogenic activity of WAVE3. We show that phosphorylation of WAVE3 PRD is essential for migration and invasion of breast cancer cells in vitro, as well as tumor growth and metastasis in vivo. Mechanistically, we show that phosphorylation of the WAVE3 PRD is essential for interaction between WAVE3 and YB1. Loss of PRD phosphorylation inhibits such interaction and the YB1-mediated activation of expression of CSC markers, as well as the WAVE3 mediated activation of EMT. Together, our study identifies a novel role of WAVE3 and its PRD domain in the regulation of the invasion metastasis cascade in BC that is independent of the known function of WAVE3 as an actin cytoskeleton remodeling protein through the WAVE regulatory complex (WRC).

Targeting WASF3 Signaling in Metastatic Cancer

Increasing evidence indicates that cancer metastasis is regulated by specific genetic pathways independent of those controlling tumorigenesis and cancer growth. WASF3, a Wiskott–Aldrich syndrome protein family member, appears to play a major role not only in the regulation of actin cytoskeleton dynamics but also in cancer cell invasion/metastasis. Recent studies have highlighted that WASF3 is a master regulator and acts as a pivotal scaffolding protein, bringing the various components of metastatic signaling complexes together both spatially and temporally. Herein, targeting WASF3 at the levels of transcription, protein stability, and phosphorylation holds great promise for metastasis suppression, regardless of the diverse genetic backgrounds associated with tumor development. This review focuses on the critical and distinct contributions of WASF3 in the regulation of signal pathways promoting cancer cell invasion and metastasis.

Deficiency of Wiskott-Aldrich syndrome protein has opposing effect on the pro-oncogenic pathway activation in nonmalignant versus malignant lymphocytes

Immunodeficiency is associated with cancer risk. Accordingly, hematolymphoid cancers develop in Wiskott-Aldrich syndrome (WAS), an X-linked primary immunodeficiency disorder (PID) resulting from the deficiency of WAS-protein (WASp) expressed predominantly in the hematolymphoid cell lineages. Despite the correlation between WASp deficiency and hematolymphoid cancers, the molecular mechanism underlying the oncogenic role of WASp is incompletely understood. Employing the WASp-sufficient and WASp-deficient cell-pair model of human T and B lymphocytes, we show that WASp deficiency differentially influences hyperactivation versus inhibition of both CDC42:ERK1/2 and NF-κB:AP-1 pro-oncogenic signaling pathways in nonmalignant versus malignant T and B lymphocytes. Furthermore, WASp deficiency induces a cell-type specific up/down-modulation of the DNA-binding activities of NF-κB, AP-1, and multiple other transcription factors with known roles in oncogenesis. We propose that WASp functions as a putative "tumor-suppressor" protein in normal T and B cells, and "oncoprotein" in a subset of established T and B cell malignancies that are not associated with the NPM-ALK fusion.

WAVE1 and WAVE2 have distinct and overlapping roles in controlling actin assembly at the leading edge

SCAR/WAVE proteins and Arp2/3 complex assemble branched actin networks at the leading edge. Two isoforms of SCAR/WAVE, WAVE1 and WAVE2, reside at the leading edge, yet it has remained unclear whether they perform similar or distinct roles. Further, there have been conflicting reports about the Arp2/3-independent biochemical activities of WAVE1 on actin filament elongation. To investigate this in vivo, we knocked out WAVE1 and WAVE2 genes, individually and together, in B16-F1 melanoma cells. We demonstrate that WAVE1 and WAVE2 are redundant for lamellipodia formation and motility. However, there is a significant decrease in the rate of leading edge actin extension in WAVE2 KO cells, and an increase in WAVE1 KO cells. The faster rates of actin extension in WAVE1 KO cells are offset by faster retrograde flow, and therefore do not translate into faster lamellipodium protrusion. Thus, WAVE1 restricts the rate of actin extension at the leading edge, and appears to couple actin networks to the membrane to drive protrusion. Overall, these results suggest that WAVE1 and WAVE2 have redundant roles in promoting Arp2/3-dependent actin nucleation and lamellipodia formation, but distinct roles in controlling actin network extension and harnessing network growth to cell protrusion.

WAVE2 Enhanced Hepatic Stellate Cells Activity in Colorectal Liver Metastases

Background

Cancer cell migration, tumor angiogenesis, and activated hepatic stellate cells (a-HSCs) promote the development of colorectal liver metastases (CLM). Wiskott–Aldrich syndrome protein family verprolin-homologous protein 2 (WAVE2) has been associated with CLM, although the underlying molecular mechanisms remain unclear.

Methods

In the current study, we evaluated the relationship between WAVE2 and CLM in 103 CLM patients who underwent liver resection. Immunohistochemistry (IHC) staining was performed to determine the association between WAVE2 protein expression and hepatic micro-metastasis in human CLM tissues. WAVE2 knockout was performed in hepatic stellate cells (HSC) to explore the function and signaling pathways of WAVE2 in colorectal cancer progression.

Results

Significantly higher levels of WAVE2 were detected in portal-associated relative to sinusoid-associated micro-metastasis. A strong correlation was identified between WAVE2 levels and microvessel density (MVD) in hepatic metastasis. Similarly, expression of WAVE2 was closely associated with activation of HSCs. Mechanistically, WAVE2 regulated the progression of human CLM acts by regulating the growth factor β (TGF-β) and Hippo pathways via effector yes-associated protein (YAP1).

Conclusion

Overall, our results demonstrated that WAVE2 participates in CLM tumor microenvironment, and can be a potential latent therapeutic target for CLM.

Actin regulators in cancer progression and metastases: From structure and function to cytoskeletal dynamics

The cytoskeleton is a central factor contributing to various hallmarks of cancer. In recent years, there has been increasing evidence demonstrating the involvement of actin regulatory proteins in malignancy, and their dysregulation was shown to predict poor clinical prognosis. Although enhanced cytoskeletal activity is often associated with cancer progression, the expression of several inducers of actin polymerization is remarkably reduced in certain malignancies, and it is not completely clear how these changes promote tumorigenesis and metastases. The complexities involved in cytoskeletal induction of cancer progression therefore pose considerable difficulties for therapeutic intervention; it is not always clear which cytoskeletal regulator should be targeted in order to impede cancer progression, and whether this targeting may inadvertently enhance alternative invasive pathways which can aggravate tumor growth. The entire constellation of cytoskeletal machineries in eukaryotic cells are numerous and complex; the system is comprised of and regulated by hundreds of proteins, which could not be covered in a single review. Therefore, we will focus here on the actin cytoskeleton, which encompasses the biological machinery behind most of the key cellular functions altered in cancer, with specific emphasis on actin nucleating factors and nucleation-promoting factors. Finally, we discuss current therapeutic strategies for cancer which aim to target the cytoskeleton.

Potential Role of Tocotrienols on Non-Communicable Diseases: A Review of Current Evidence

Tocotrienol (T3) is a subfamily of vitamin E known for its wide array of medicinal properties. This review aimed to summarize the health benefits of T3, particularly in prevention or treatment of non-communicable diseases (NCDs), including cardiovascular, musculoskeletal, metabolic, gastric, and skin disorders, as well as cancers. Studies showed that T3 could prevent various NCDs, by suppressing 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in the mevalonate pathway, inflammatory response, oxidative stress, and alternating hormones. The efficacy of T3 in preventing/treating these NCDs is similar or greater compared to tocopherol (TF). TF may lower the efficacy of T3 because the efficacy of the combination of TF and T3 was lower than T3 alone in some studies. Data investigating the effects of T3 on osteoporosis, arthritis, and peptic ulcers in human are limited. The positive outcomes of T3 treatment obtained from the preclinical studies warrant further validation from clinical trials.

Cell confinement reveals a branched-actin independent circuit for neutrophil polarity

Migratory cells use distinct motility modes to navigate different microenvironments, but it is unclear whether these modes rely on the same core set of polarity components. To investigate this, we disrupted actin-related protein 2/3 (Arp2/3) and the WASP-family verprolin homologous protein (WAVE) complex, which assemble branched actin networks that are essential for neutrophil polarity and motility in standard adherent conditions. Surprisingly, confinement rescues polarity and movement of neutrophils lacking these components, revealing a processive bleb-based protrusion program that is mechanistically distinct from the branched actin-based protrusion program but shares some of the same core components and underlying molecular logic. We further find that the restriction of protrusion growth to one site does not always respond to membrane tension directly, as previously thought, but may rely on closely linked properties such as local membrane curvature. Our work reveals a hidden circuit for neutrophil polarity and indicates that cells have distinct molecular mechanisms for polarization that dominate in different microenvironments.

Cells display a high degree of plasticity in migration, but how polarity is organized in different microenvironments has remained unclear. This study uses mechanical perturbations to reveal that migration using actin-rich or bleb-based protrusions are both organized around Rac GTPase.

RPEL-family rhoGAPs link Rac/Cdc42 GTP loading to G-actin availability

RPEL proteins, which contain the G-actin-binding RPEL motif, coordinate cytoskeletal processes with actin dynamics. We show that the ArhGAP12- and ArhGAP32-family GTPase-activating proteins (GAPs) are RPEL proteins. We determine the structure of the ArhGAP12/G-actin complex, and show that G-actin contacts the RPEL motif and GAP domain sequences. G-actin inhibits ArhGAP12 GAP activity, and this requires the G-actin contacts identified in the structure. In B16 melanoma cells, ArhGAP12 suppresses basal Rac and Cdc42 activity, F-actin assembly, invadopodia formation and experimental metastasis. In this setting, ArhGAP12 mutants defective for G-actin binding exhibit more effective downregulation of Rac GTP loading following HGF stimulation and enhanced inhibition of Rac-dependent processes, including invadopodia formation. Potentiation or disruption of the G-actin/ArhGAP12 interaction, by treatment with the actin-binding drugs latrunculin B or cytochalasin D, has corresponding effects on Rac GTP loading. The interaction of G-actin with RPEL-family rhoGAPs thus provides a negative feedback loop that couples Rac activity to actin dynamics.

Low-diluted Phenacetinum disrupted the melanoma cancer cell migration

Dynamic and reciprocal interactions generated by the communication between tumor cells and their matrix microenvironment, play a major role in the progression of a tumor. Indeed, the adhesion of specific sites to matrix components, associated with the repeated and coordinated formation of membrane protrusions, allow tumor cells to move along a determined pathway. Our study analyzed the mechanism of action of low-diluted Phenacetinum on murine cutaneous melanoma process in a fibronectin matrix environment. We demonstrated a reduction of dispersed cell migration, early and for as long as 24 h, by altering the formation of cell protrusions. Moreover, low-diluted Phenacetinum decreased cell stiffness highly on peripheral areas, due to a disruption of actin filaments located just under the plasma membrane. Finally, it modified the structure of the plasma membrane by accumulating large ordered lipid domains and disrupted B16 cell migration by a likely shift in the balance between ordered and disordered lipid phases. Whereas the correlation between the excess of lipid raft and cytoskeleton disrupting is not as yet established, it is clear that low-diluted Phenacetinum acts on the actin cytoskeleton organization, as confirmed by a decrease of cell stiffness affecting ultimately the establishment of an effective migration process.

Modulation of CD44, EGFR and RAC Pathway Genes (WAVE Complex) in Epithelial Cancers

Cancer hallmarks help in understanding the diversity of various neoplasms. Epithelial cancers play an immense role in the tumor biology through Epithelial-Mesenchymal Transition (EMT) process. Receptor tyrosine kinase, as well as phosphatidyl ionositol-3 kinase pathways, play an important role in the regulation of cell proliferation, survival, and differentiation during EMT. Till date, numerous studies have shown modulation in the expression profile of potential targets like CD44, EGFR, and Rac in epithelial cancers. CD44 interacts with EGFR and recruits other molecules which further activate the Rac pathway intermediates. This review mainly focused on modulation of genes like CD44, EGFR, and Rac pathway intermediates which play a crucial role in the tumor progression, metastasis, proliferation, and invasion characteristics in epithelial cancers with EMT properties. Hence, targeting Rac pathway might be a more strategically relevant approach in treating epithelial cancers.

MiR-133b targets Sox9 to control pathogenesis and metastasis of breast cancer

The miR-133b, a commonly recognized muscle-specific miRNA, was reported to be deregulated in many kinds of cancers. However, its potential roles in tumorigenesis remain greatly elusive. Herein, we demonstrate that miR-133b is significantly suppressed in human breast cancer specimens, which is reversely correlated to histological grade of the cancer. Ectopic expression of miR-133b suppresses clonogenic ability and metastasis-relevant traits in vitro, as well as carcinogenesis and pulmonary metastasis in vivo. Further studies have identified Sox9, c-MET, and WAVE2 as direct targets of miR-133b, in which Sox9 contributes to all miR-133b-endowed effects including cell proliferation, colony formation, as well as cell migration and invasion in vitro. Moreover, re-expression of Sox9 reverses miR-133b-mediated metastasis suppression in vivo. Taken together, these findings highlight an important role for miR-133b in the regulation of tumorigenesis and metastatic potential of breast cancer and suggest a potential application of miR-133b in cancer treatment.

High WAVE3 expression correlates with proliferation, migration and invasion in human ovarian cancer

BACKGROUND

Wiskott-Aldrich syndrome verprolin-homologous (WAVE) 3, a member of the WASP/WAVE family of proteins, plays a critical role in cell motility and acts as an oncogene in some human cancers, but no sufficient information available to illustrate its involvement in ovarian cancer tumorigenesis and progression.

METHODS

The expression of WAVE3 in human ovarian cancer and normal tissue was analyzed by immunohistochemistry. WAVE3 gene and protein expression in different human ovarian cancer cell lines was tested by RT-PCR and western blotting. Stable cells of WAVE3-knockdown in SKOV3 cells or transfected high expression in A2780 cells were constructed. The WAVE3 expression and its correlation with MMPs, p38 MAPK and other factors were studied. The relationship between WAVE3 and oncogenicity in vivo was also evaluated by nude mice xenograft model.

RESULTS

Immunohistochemistry staining showed the highest WAVE3 expression in ovarian cancer metastases, high in ovarian cancer and weak in normal. In different cell lines, SKOV3 cells showed the highest WAVE3 expression, A2780 cells expressed the lowest. Elevated WAVE3 expression in A2780 cells promoted proliferation and decreased apoptosis, increased the cell number in G2/M phase and promoted migration significantly. Correspondingly, knockdown of WAVE3 in SKOV3 cells showed opposite effects. The WAVE3 expression showed positive correlation with MMPs, NF-κB, COX-2, VEGF and phospho-p38 MAPK, but not p38. The high expression of WAVE3 promoted tumorigenesis in vivo.

CONCLUSIONS

Our results suggested that WAVE3 may be pivotal in ovarian cancer cell motility, invasion and oncogenesis, which might be related with MMPs production and p38 MAPK pathway.

Tumor suppressor miR-1 inhibits tumor growth and metastasis by simultaneously targeting multiple genes

Cancer progression depends on tumor growth and metastasis, which are activated or suppressed by multiple genes. An individual microRNA may target multiple genes, suggesting that a miRNA may suppress tumor growth and metastasis via simultaneously targeting different genes. However, thus far, this issue has not been explored. In the present study, the findings showed that miR-1 could simultaneously inhibit tumor growth and metastasis of gastric and breast cancers by targeting multiple genes. The results indicated that miR-1 was significantly downregulated in cancer tissues compared with normal tissues. The miR-1 overexpression led to cell cycle arrest in the G1 phase in gastric and breast cancer cells but not in normal cells. Furthermore, the miR-1 overexpression significantly inhibited the metastasis of gastric and breast cancer cells. An analysis of the underlying mechanism revealed that the simultaneous inhibition of tumor growth and metastasis mediated by miR-1 was due to the synchronous targeting of 6 miR-1 target genes encoding cyclin dependent kinase 4, twinfilin actin binding protein 1, calponin 3, coronin 1C, WAS protein family member 2 and thymosin beta 4, X-linked. In vivo assays demonstrated that miR-1 efficiently inhibited tumor growth and metastasis of gastric and breast cancers in nude mice. Therefore, our study contributed novel insights into the miR-1′s roles in tumorigenesis of gastric and breast cancers.

Characterization of a Dual Rac/Cdc42 Inhibitor MBQ-167 in Metastatic Cancer

The Rho GTPases Rac (Ras-related C3 botulinum toxin substrate) and Cdc42 (cell division control protein 42 homolog) regulate cell functions governing cancer malignancy, including cell polarity, migration, and cell-cycle progression. Accordingly, our recently developed Rac inhibitor EHop-016 (IC₅₀, 1,100 nmol/L) inhibits cancer cell migration and viability and reduces tumor growth, metastasis, and angiogenesis in vivo Herein, we describe MBQ-167, which inhibits Rac and Cdc42 with IC₅₀ values of 103 and 78 nmol/L, respectively, in metastatic breast cancer cells. Consequently, MBQ-167 significantly decreases Rac and Cdc42 downstream effector p21-activated kinase (PAK) signaling and the activity of STAT3, without affecting Rho, MAPK, or Akt activities. MBQ-167 also inhibits breast cancer cell migration, viability, and mammosphere formation. Moreover, MBQ-167 affects cancer cells that have undergone epithelial-to-mesenchymal transition by a loss of cell polarity and inhibition of cell surface actin-based extensions to ultimately result in detachment from the substratum. Prolonged incubation (120 hours) in MBQ-167 decreases metastatic cancer cell viability with a GI₅₀ of approximately 130 nmol/L, without affecting noncancer mammary epithelial cells. The loss in cancer cell viability is due to MBQ-167-mediated G₂-M cell-cycle arrest and subsequent apoptosis, especially of the detached cells. In vivo, MBQ-167 inhibits mammary tumor growth and metastasis in immunocompromised mice by approximately 90%. In conclusion, MBQ-167 is 10× more potent than other currently available Rac/Cdc42 inhibitors and has the potential to be developed as an anticancer drug, as well as a dual inhibitory probe for the study of Rac and Cdc42. Mol Cancer Ther; 16(5); 805-18. ©2017 AACR.

ABI3, a component of the WAVE2 complex, is potentially regulated by PI3K/AKT pathway

We previously reported that ABI3 expression is lost in follicular thyroid carcinomas and its restoration significantly inhibited cell growth, invasiveness, migration, and reduced tumor growth in vivo. The mechanistic basis by which ABI3 exerts its tumor suppressive effects is not fully understood. In this study, we show that ABI3 is a phosphoprotein. Using proteomic array analysis, we showed that ABI3 modulated distinct cancer-related pathways in thyroid cancer cells. The KEA analysis found that PI3K substrates were enriched and forced expression of ABI3 markedly decreased the phosphorylation of AKT and the downstream-targeted protein pGSK3β. We next used immunoprecipitation combined with mass spectrometry to identify ABI3-interacting proteins that may be involved in modulating/integrating signaling pathways. We identified 37 ABI3 partners, including several components of the canonical WAVE regulatory complex (WRC) such as WAVE2/CYF1P1/NAP1, suggesting that ABI3 function might be regulated through WRC. Both, pharmacological inhibition of the PI3K/AKT pathway and mutation at residue S342 of ABI3, which is predicted to be phosphorylated by AKT, provided evidences that the non-phosphorylated form of ABI3 is preferentially present in the WRC protein complex. Collectively, our findings suggest that ABI3 might be a downstream mediator of the PI3K/AKT pathway that might disrupt WRC via ABI3 phosphorylation.

SH3-domain binding protein 1 in the tumor microenvironment promotes hepatocellular carcinoma metastasis through WAVE2 pathway

SH3-domain binding protein-1 (SH3BP1) specifically inactivating Rac1 and its target WAVE2 is required for cell motility. The present study shows SH3BP1 expression patterns in human HCC tissues and cell lines were examined. The regulation of SH3BP1 on HCC cell migration and invasion related to Rac1-WAVE2 signaling was characterized using in vitro and in vivo models. SH3BP1 overexpressed in HCC tissues and highly metastatic HCC cells was significantly associated vascular invasion (VI). SH3BP1 promoted VEGF secretion via Rac1-WAVE2 signaling, so as to exert an augmentation on cell invasion and microvessel formation. In three study cohorts with a total of 516 HCC patients, high SH3BP1 expression combined with high microvessel density (MVD) was confirmed as a powerful independent predictor of HCC prognosis in both training cohorts and validation cohort. Being an important angiogenic factor of HCC through Rac1-WAVE2 signaling, SH3BP1 promotes tumor invasion and microvessel formation contributing to HCC metastasis and recurrence. SH3BP1 is a novel WAVE2 regulator, a prognostic marker and a potential therapeutic target of HCC.

Role of Rac1/WAVE2 Signaling in Mediating the Inhibitory Effects of γ-Tocotrienol on Mammary Cancer Cell Migration and Invasion

The majority of breast cancer deaths result from the progression of this disease to a metastatic phenotype. Rac1 and Cdc42 are Rho family members that together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, play an important role in cytoskeletal reorganization and the formation of membrane protrusions that promote cancer cell migration and invasion. γ-Tocotrienol, is a natural isoform within the vitamin E family of compounds that inhibits breast cancer cell growth and progression by suppressing various signaling pathways involved in mitogenic signaling and metastatic progression. Studies were conducted to examine the effects of γ-tocotrienol on Rac1/WAVE2 signaling dependent migration and invasion in highly metastatic mouse +SA and human MDA-MB-231 mammary cancer cells. Exposure to γ-tocotrienol resulted in a dose-responsive decrease in Rac1/WAVE2 signaling as characterized by a suppression in the levels of Rac1/Cdc42, phospho-Rac1/Cdc42, WAVE2, Arp2, and Arp3 expression. Additional studies also demonstrated that similar treatment with γ-tocotrienol resulted in a significant reduction in tumor cell migration and invasion. Taken together, these findings indicate that γ-tocotrienol treatment effectively inhibits Rac1/WAVE2 signaling and reduces metastatic phenotypic expression in mammary cancer cells, suggesting that γ-tocotrienol may provide some benefit as a novel therapeutic approach in the treatment of metastatic breast cancer.

Small GTPase RBJ promotes cancer progression by mobilizing MDSCs via IL-6

RBJ has been identified to be dysregulated in gastrointestinal cancer and promotes tumorigenesis and progression by mediating nuclear accumulation of active MEK1/2 and sustained activation of ERK1/2. Considering that nuclear accumulation and constitutive activation of MEK/ERK not only promotes tumor progression directly, but also induces chronic inflammation, we wonder whether and how RBJ impairs host immune-surveillance via chronic inflammation and consequently supports tumor progression. Here, we report that higher expression of RBJ in human breast cancer tissue has been significantly correlated with poorer prognosis in breast cancer patients. The forced expression of RBJ promotes tumor growth and metastasis both in vitro and in vivo. In addition, more accumulation of immune suppressive cells but less antitumor immune cell subpopulations were found in spleen and tumor tissue derived from RBJ force-expressed tumor-bearing mice. Furthermore, forced RBJ expression significantly promotes tumor cell production of pro-inflammatory cytokine IL-6 by constitutive activating MEK/ERK signaling pathway. Accordingly, RBJ knockdown significantly decreases tumor growth and metastasis in vitro and in vivo, with markedly reduced production of IL-6. Administration of anti-IL-6 neutralizing antibody could reduce MDSCs accumulation in tumor tissue in vivo. Therefore, our results demonstrate that RBJ-mediated nuclear constitutive activation of ERK1/2 leads to persistent production of IL-6 and increase of MDSCs recruitment, contributing to promotion of tumor growth and metastasis. These results suggest that RBJ contributes to tumor immune escape, maybe serving a potential target for design of antitumor drug.

Evaluating Biomaterial- and Microfluidic-Based 3D Tumor Models

Cancer is a major cause of morbidity and mortality worldwide, with a disease burden estimated to increase over the coming decades. Disease heterogeneity and limited information on cancer biology and disease mechanisms are aspects that 2D cell cultures fail to address. Here, we review the current ‘state-of-the-art’ in 3D tissue-engineering (TE) models developed for, and used in, cancer research. We assess the potential for scaffold-based TE models and microfluidics to fill the gap between 2D models and clinical application. We also discuss recent advances in combining the principles of 3D TE models and microfluidics, with a special focus on biomaterials and the most promising chip-based 3D models.

RTVP-1 regulates glioma cell migration and invasion via interaction with N-WASP and hnRNPK

Glioblastoma (GBM) are characterized by increased invasion into the surrounding normal brain tissue. RTVP-1 is highly expressed in GBM and regulates the migration and invasion of glioma cells. To further study RTVP-1 effects we performed a pull-down assay using His-tagged RTVP-1 followed by mass spectrometry and found that RTVP-1 was associated with the actin polymerization regulator, N-WASP. This association was further validated by co-immunoprecipitation and FRET analysis. We found that RTVP-1 increased cell spreading, migration and invasion and these effects were at least partly mediated by N-WASP. Another protein which was found by the pull-down assay to interact with RTVP-1 is hnRNPK. This protein has been recently reported to associate with and to inhibit the effect of N-WASP on cell spreading. hnRNPK decreased cell migration, spreading and invasion in glioma cells. Using co-immunoprecipitation we validated the interactions of hnRNPK with N-WASP and RTVP-1 in glioma cells. In addition, we found that overexpression of RTVP-1 decreased the association of N-WASP and hnRNPK. In summary, we report that RTVP-1 regulates glioma cell spreading, migration and invasion and that these effects are mediated via interaction with N-WASP and by interfering with the inhibitory effect of hnRNPK on the function of this protein.

Swiprosin-1 stimulates cancer invasion and metastasis by increasing the Rho family of GTPase signaling

Ectopic expression of Swiprosin-1, an actin-binding protein (also known as EF hand domain containing 2; EFHD2), enhanced motile protrusions associated with actin, such as lamellipodia and membrane ruffles. Swiprosin-1 levels were increased in various human cancer tissues, particularly at highly invasive stages of malignant melanoma. Expression of Swiprosin-1 was correlated with that of epidermal growth factor receptor (EGFR) and induced by EGF. In a mouse metastasis model, Swiprosin-1 overexpression induced pulmonary metastasis whereas its knockdown led to marked inhibition of metastasis of highly invasive melanoma cells. Swiprosin-1 at the lamellipodia and membrane ruffles controlled the direction of cell protrusion and enhanced migration velocity through activating the Rho family of small GTPases, including Rac1, Cdc42 and RhoA. Our collective findings support the potential utility of Swiprosin-1 as a therapeutic target to prevent cancer invasion and metastasis.

Systematic analysis of copy number variants of a large cohort of orofacial cleft patients identifies candidate genes for orofacial clefts

Orofacial clefts (OFCs) represent a large fraction of human birth defects and are one of the most common phenotypes affected by large copy number variants (CNVs). Due to the limited number of CNV patients in individual centers, CNV analyses of a large number of OFC patients are challenging. The present study analyzed 249 genomic deletions and 226 duplications from a cohort of 312 OFC patients reported in two publicly accessible databases of chromosome imbalance and phenotype in humans, DECIPHER and ECARUCA. Genomic regions deleted or duplicated in multiple patients were identified, and genes in these overlapping CNVs were prioritized based on the number of genes encompassed by the region and gene expression in embryonic mouse palate. Our analyses of these overlapping CNVs identified two genes known to be causative for human OFCs, SATB2 and MEIS2, and 12 genes (DGCR6, FGF2, FRZB, LETM1, MAPK3, SPRY1, THBS1, TSHZ1, TTC28, TULP4, WHSC1, WHSC2) that are associated with OFC or orofacial development. Additionally, we report 34 deleted and 24 duplicated genes that have not previously been associated with OFCs but are associated with the BMP, MAPK and RAC1 pathways. Statistical analyses show that the high number of overlapping CNVs is not due to random occurrence. The identified genes are not located in highly variable genomic regions in healthy populations and are significantly enriched for genes that are involved in orofacial development. In summary, we report a CNV analysis pipeline of a large cohort of OFC patients and identify novel candidate OFC genes.

Analysis of miRNA expression profiling in mouse spleen affected by acute Toxoplasma gondii infection

Toxoplasma gondii is a worldwide prevalent pathogen that infects most of the warm-blood vertebrates. To investigate the regulation network of splenic miRNAs altered by acute infection with T. gondii, we herein investigated the changes of miRNA profile in mouse spleen via next generation sequencing and bioinformatics analysis. A total of 379 miRNAs was identified, 131 miRNAs of them were differentially expressed (including 97 upregulated and 34 downregulated miRNAs). 48 differentially expressed miRNAs had validated targets in the miRWalk2.0 database. Gene Ontology (GO) enrichment analysis revealed that the validated targets of differently expressed miRNAs were significantly enriched in gene transcription regulation. It suggested that T. gondii can modulate host gene expression through targeting to trans-regulation factors. The genes involved in apoptosis or anti-apoptosis were both targeted by differentially expressed miRNAs. The change of power balance between the miRNAs targeting host apoptosis genes and those regulating host anti-apoptosis genes contributes to the fate of host apoptosis process. Twelve pathways were significantly enriched in KEGG analysis with most of them being cancer related, including pathways in cancer, pancreatic cancer, colorectal cancer, axon guidance, MAPK signaling pathway, focal adhesion, chronic myeloid leukemia, renal cell carcinoma, prostate cancer, glioma, regulation of actin cytoskeleton, and Wnt signaling pathway. Our study showed a changed miRNA regulation network in mouse spleen infected by T. gondii. These findings will be helpful for better understanding of miRNA regulation network in host-T. gondii interaction, revealing the relationship among T. gondii infection, gene regulation, apoptosis and cancer process alterations in infected spleen.

Hexane extract from Sargassum serratifolium inhibits the cell proliferation and metastatic ability of human glioblastoma U87MG cells

The present study is the first to demonstrate the anticancer effects of a hexane extract from the brown algae Sargassum serratifolium (HES) on human cancer cell lines, including glioblastoma U87MG, cervical cancer HeLa and gastric cancer MKN-28 cells, as well as liver cancer SK-HEP 1 cells. Among these cancer cell lines, U87MG cells were most sensitive to the cell death induced by HES. HES exhibited a cytotoxic effect on U87MG cells at concentrations of 14-16 µg/ml, yet an effect was not observed in human embryonic kidney HEK293 cells. The antiproliferative effects of HES were regulated by inhibition of the MAPK/ERK signaling pathway which plays a pivotal role in the proliferation of glioblastoma U87MG cells. In addition, treatment with HES led to cell morphological changes and cell cytoskeleton degradation through regulation of actin dynamic signaling. Furthermore, migration and invasion of the U87MG cells were inhibited by HES via suppression of matrix metalloproteinase (MMP)-2 and -9 expression. Thus, our results suggest that HES is a potential therapeutic agent which has anticancer effects on glioblastoma.

Role of the WASP and WAVE family proteins in breast cancer invasion and metastasis

The Wiskott–Aldrich syndrome protein (WASP) and WASP family verprolin-homologous protein (WAVE) family are a group of molecules that form a key link between GTPases and the actin cytoskeleton. The role of WASP/WAVE family proteins in the control of actin polymerization through activation of the actin-related protein 2/3 complex is critical in the formation of the actin-based membrane protrusions seen in cell migration and invasion. For this reason, the activity of the WASP/WAVE family in cancer cell invasion and migration has been of great interest in recent years. Many reports have highlighted the potential of targeting the WASP/WAVE family as a therapy for the prevention of cancer progression, in particular breast cancer. This review focuses on the role of the WASP/WAVE family in breast cancer cell invasion and migration and how this relates to the molecular mechanisms of WASP/WAVE activity, their exact contributions to the stages of cancer progression, and how this can lead to the development of anticancer drugs that target the WASP/WAVE family and related pathways.

α-Actinin-4 enhances colorectal cancer cell invasion by suppressing focal adhesion maturation

α-Actinins (ACTNs) are known to crosslink actin filaments at focal adhesions in migrating cells. Among the four isoforms of mammalian ACTNs, ACTN1 and ACTN4 are ubiquitously expressed. Recently, ACTN4 was reported to enhance cancer cell motility, invasion, and metastasis. However, the mechanism by which ACTN4 drives these malignant phenotypes remains unclear. Here, we show that ACTN4, but not ACTN1, induces the formation of immature focal adhesions in DLD-1 cells, leading to the rapid turnover of focal adhesions. Interestingly, zyxin (ZYX) assembly to focal adhesions was markedly decreased in ACTN4-expressing DLD-1 cells, while the recruitment of paxillin (PAX) occurred normally. On the other hand, in ACTN1-expressing DLD-1 cells, PAX and ZYX were normally recruited to focal adhesions, suggesting that ACTN4 specifically impairs focal adhesion maturation by inhibiting the recruitment of ZYX to focal complexes. Using purified recombinant proteins, we found that ZYX binding to ACTN4 was defective under conditions where ZYX binding to ACTN1 was observed. Furthermore, Matrigel invasion of SW480 cells that express high endogenous levels of ACTN4 protein was inhibited by ectopic expression of ACTN1. Altogether, our results suggest that ZYX defective binding to ACTN4, which occupies focal adhesions instead of ACTN1, induces the formation of immature focal adhesions, resulting in the enhancement of cell motility and invasion.

Membrane protein CNNM4-dependent Mg2+ efflux suppresses tumor progression

Intracellular Mg(2+) levels are strictly regulated; however, the biological importance of intracellular Mg(2+) levels and the pathways that regulate them remain poorly understood. Here, we determined that intracellular Mg(2+) is important in regulating both energy metabolism and tumor progression. We determined that CNNM4, a membrane protein that stimulates Mg(2+) efflux, binds phosphatase of regenerating liver (PRL), which is frequently overexpressed in malignant human cancers. Biochemical analyses of cultured cells revealed that PRL prevents CNNM4-dependent Mg(2+) efflux and that regulation of intracellular Mg(2+) levels by PRL and CNNM4 is linked to energy metabolism and AMPK/mTOR signaling. Indeed, treatment with the clinically available mTOR inhibitor rapamycin suppressed the growth of cancer cells in which PRL was overexpressed. In ApcΔ(14/+) mice, which spontaneously form benign polyps in the intestine, deletion of Cnnm4 promoted malignant progression of intestinal polyps to adenocarcinomas. IHC analyses of tissues from patients with colon cancer demonstrated an inverse relationship between CNNM4 expression and colon cancer malignancy. Together, these results indicate that CNNM4-dependent Mg(2+) efflux suppresses tumor progression by regulating energy metabolism.

The three-way switch operation of Rac1/RhoA GTPase-based circuit controlling amoeboid-hybrid-mesenchymal transition

Metastatic carcinoma cells exhibit at least two different phenotypes of motility and invasion - amoeboid and mesenchymal. This plasticity poses a major clinical challenge for treating metastasis, while its underlying mechanisms remain enigmatic. Transitions between these phenotypes are mediated by the Rac1/RhoA circuit that responds to external signals such as HGF/SF via c-MET pathway. Using detailed modeling of GTPase-based regulation to study the Rac1/RhoA circuit's dynamics, we found that it can operate as a three-way switch. We propose to associate the circuit's three possible states to the amoeboid, mesenchymal and amoeboid/mesenchymal hybrid phenotype. In particular, we investigated the range of existence of, and the transition between, the three states (phenotypes) in response to Grb2 and Gab1 - two downstream adaptors of c-MET. The results help to explain the regulation of metastatic cells by c-MET pathway and hence can contribute to the assessment of possible clinical interventions.