Phenotypic Plasticity of Cancer Cells Based on Remodeling of the Actin Cytoskeleton and Adhesive Structures

A Recipe for Successful Metastasis: Transition and Migratory Modes of Ovarian Cancer Cells

One of the characteristic features of ovarian cancer is its early dissemination. Metastasis and the invasiveness of ovarian cancer are strongly dependent on the phenotypical and molecular determinants of cancer cells. Invasive cancer cells, circulating tumor cells, and cancer stem cells, which are responsible for the metastatic process, may all undergo different modes of transition, giving rise to mesenchymal, amoeboid, and redifferentiated epithelial cells. Such variability is the result of the changing needs of cancer cells, which strive to survive and colonize new organs. This would not be possible if not for the variety of migration modes adopted by the transformed cells. The most common type of metastasis in ovarian cancer is dissemination through the transcoelomic route, but transitions in ovarian cancer cells contribute greatly to hematogenous and lymphatic dissemination. This review aims to outline the transition modes of ovarian cancer cells and discuss the migratory capabilities of those cells in light of the known ovarian cancer metastasis routes.

Molecular basis and current insights of atypical Rho small GTPase in cancer

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.

Mechanism and application of β-adrenoceptor blockers in soft tissue wound healing

Soft tissue damage stimulates sympathetic nerves to release large amounts of catecholamine hormones which bind to β-adrenergic receptors (β-ARs) on the cell membrane surface. It activates the downstream effector molecules and impairs soft tissue wound healing. β-blockers specifically inhibit β-ARs activation in acute/chronic skin lesions and ulcerative hemangiomas. They also accelerate soft tissue wound healing by shortening the duration of inflammation, speeding keratinocyte migration and reepithelialization, promoting wound contraction and angiogenesis, and inhibiting bacterial virulence effects. In addition, β-blockers shorten wound healing periods in patients with severe thermal damage by reducing the hypermetabolic response. While β-blockers promote/inhibit corneal epithelial cell regeneration and restores limbal stem/progenitor cells function, it could well accelerate/delay corneal wound healing. Given these meaningful effects, a growing number of studies are focused on examining the efficacy and safety of β-blockers in soft tissue wound repair, including acute and chronic wounds, severe thermal damage, ulcerated infantile hemangioma, corneal wounds, and other soft tissue disorders. However, an intensive investigation on their acting mechanisms is imperatively needed. The purpose of this article is to summerize the roles of β-blockers in soft tissue wound healing and explore their clinical applications.

Proteomics identifies apoptotic markers as predictors of histological transformation in patients with follicular lymphoma

Follicular lymphoma (FL) is an indolent lymphoma with a generally favorable prognosis. However, histological transformation (HT) to a more aggressive disease leads to markedly inferior outcomes. This study aims to identify biological differences predictive of HT at the time of initial FL diagnosis. We show differential protein expression between diagnostic lymphoma samples from patients with subsequent HT (subsequently-transforming FL [st-FL]; n = 20) and patients without HT (nontransforming FL [nt-FL]; n = 34) by label-free quantification nano liquid chromatography-tandem mass spectrometry analysis. Protein profiles identified patients with high risk of HT. This was accompanied by disturbances in cellular pathways influencing apoptosis, the cytoskeleton, cell cycle, and immune processes. Comparisons between diagnostic st-FL samples and paired transformed FL (n = 20) samples demonstrated differential protein profiles and disrupted cellular pathways, indicating striking biological differences from the time of diagnosis up to HT. Immunohistochemical analysis of apoptotic proteins, CASP3, MCL1, BAX, BCL-xL, and BCL-rambo, confirmed higher expression levels in st-FL than in nt-FL samples (P < .001, P = .015, P = .003, P = .025, and P = .057, respectively). Moreover, all 5 markers were associated with shorter transformation-free survival (TFS; P < .001, P = .002, P < .001, P = .069, and P = .010, respectively). Notably, combining the expression of these proteins in a risk score revealed increasingly inferior TFS with an increasing number of positive markers. In conclusion, proteomics identified altered protein expression profiles (particularly apoptotic proteins) at the time of FL diagnosis, which predicted later transformation.

ARAP1 negatively regulates stress fibers formation and metastasis in lung adenocarcinoma via controlling Rho signaling

Small GTPases regulate multiple important cellular behaviors and their activities are strictly controlled by a mass of regulators. The dysfunction or abnormal expression of small GTPases or their regulators was frequently observed in various cancers. Here, we analyzed the expression and prognostic correlation of several GTPases and related regulators based on the TCGA database and found that Ankyrin Repeat and PH Domain 1 (ARAP1), a GTPase activating protein (GAP), is reduced in lung adenocarcinoma tissues compared to normal tissues and displays a positive correlation with overall survival (OS) and progression-free survival (PFS) of patients with lung adenocarcinoma. qPCR and western blot verified that ARAP1 is frequently downregulated in lung adenocarcinoma tumor tissues and cancer cells, and its downregulation might be mediated by epigenetic modification. Moreover, metastatic assays showed that overexpression of ARAP1 significantly inhibits metastasis of lung adenocarcinoma in vitro and in vivo. We further demonstrated that Rho signaling inhibition, mediated by RhoGAP activity of ARAP1, majorly contributes to suppressing migration and invasion of lung adenocarcinoma cancer cells via inhibiting stress fibers formation. In summary, this study indicates that ARAP1 may serve as a potential prognostic predictor and a metastatic suppressor in lung adenocarcinoma via its RhoGAP activity.

BCKDK regulates breast cancer cell adhesion and tumor metastasis by inhibiting TRIM21 ubiquitinate talin1

Breast cancer is the most common malignant cancer in women worldwide. Cancer metastasis is the major cause of cancer-related deaths. BCKDK is associated with various diseases, including proliferation, migration, and invasion in multiple types of human cancers. However, the relevance of BCKDK to the development and progression of breast cancers and its function is unclear. This study found that BCKDK was overexpressed in breast cancer, associated with poor prognosis, and implicated in tumor metastasis. The downregulation of BCKDK expression inhibited the migration of human breast cancer cells in vitro and diminished lung metastasis in vivo. BCKDK perturbed the cadherin-catenin complex at the adherens junctions (AJs) and assembled focal adhesions (FAs) onto the extracellular matrix, thereby promoting the directed migration of breast cancer cells. We observed that BCKDK acted as a conserved regulator of the ubiquitination of cytoskeletal protein talin1 and the activation of the FAK/MAPK pathway. Further studies revealed that BCKDK inhibited the binding of talin1 to E3 ubiquitin ligase-TRIM21, leading to the decreased ubiquitination/degradation of talin1. In conclusion, identifying BCKDK as a biomarker for breast cancer metastasis facilitated further research on diagnostic biomarkers. Elucidating the mechanism by which BCKDK exerted its biological effect could provide a new theoretical basis for developing new markers for breast cancer metastasis and contribute to developing new therapies for the clinical treatment of breast cancer patients.

ERK Signaling Pathway Is Constitutively Active in NT2D1 Non-Seminoma Cells and Its Inhibition Impairs Basal and HGF-Activated Cell Proliferation

c-MET/hepatocyte growth factor (HGF) system deregulation is a well-known feature of malignancy in several solid tumors, and for this reason this system and its pathway have been considered as potential targets for therapeutic purposes. In previous manuscripts we reported c-MET/HGF expression and the role in testicular germ cell tumors (TGCTs) derived cell lines. We demonstrated the key role of c-Src and phosphatidylinositol 3-kinase (PI3K)/AKT adaptors in the HGF-dependent malignant behavior of the embryonal carcinoma cell line NT2D1, finding that the inhibition of these onco-adaptor proteins abrogates HGF triggered responses such as proliferation, migration, and invasion. Expanding on these previous studies, herein we investigated the role of mitogen-activated protein kinase (MAPK)/extracellular signal regulated kinase (ERK) pathways in the HGF-dependent and HGF-independent NT2D1 cells biological responses. To inhibit MAPK/ERK pathways we chose a pharmacological approach, by using U0126 inhibitor, and we analyzed cell proliferation, collective migration, and chemotaxis. The administration of U0126 together with HGF reverts the HGF-dependent activation of cell proliferation but, surprisingly, does not exert the same effect on NT2D1 cell migration. In addition, we found that the use of U0126 alone significantly promotes the acquisition of NT2D1 «migrating phenotype», while collective migration of NT2D1 cells was stimulated. Notably, the inhibition of ERK activation in the absence of HGF stimulation resulted in the activation of the AKT-mediated pathway, and this let us speculate that the paradoxical effects obtained by using U0126, which are the increase of collective migration and the acquisition of partial epithelium-mesenchyme transition (pEMT), are the result of compensatory pathways activation. These data highlight how the specific response to pathway inhibitors, should be investigated in depth before setting up therapy.

Upregulation of dihydropyrimidinase-like 3 (DPYSL3) protein predicts poor prognosis in urothelial carcinoma

BACKGROUND

Dihydropyrimidinase-like 3 (DPYSL3) is a cytosolic phosphoprotein expressed in the nervous system and is crucial for neurogenesis. A previous study showed that increased DPYSL3 expression promotes tumour aggressiveness in pancreatic ductal adenocarcinoma, gastric cancer, and colon cancer. However, the role of DPYSL3 in affecting the biological behaviour of urothelial carcinoma (UC) is not yet understood.

METHODS

A UC transcriptomic dataset from the Gene Expression Omnibus and the Urothelial Bladder Cancer (BLCA) dataset from The Cancer Genome Atlas were used for the in silico study. We collected 340 upper urinary tract urothelial carcinoma (UTUC) and 295 urinary bladder urothelial carcinoma (UBUC) samples for the immunohistochemical study. Fresh tumour tissue from 50 patients was used to examine the DPYSL3 mRNA level. In addition, urothelial cell lines with and without DPYSL3 knockdown were used for the functional study.

RESULTS

The in silico study revealed that DPYSL3 correlated with advanced tumour stage and metastasis development while functioning primarily in the nucleobase-containing compound metabolic process (GO:0006139). DPYSL3 mRNA expression is significantly upregulated in advanced UC. Furthermore, overexpression of the DPYSL3 protein is significantly associated with the aggressive behaviour of UTUC and UBUC. DPYSL3 expression independently predicts disease-specific survival (DSS) and metastatic-free survival (MFS) in patients with UC. In non-muscle-invasive UBUC, DPYSL3 expression predicts local recurrence-free survival. UC cell lines with DPYSL3 knockdown exhibited decreased proliferation, migration, invasion, and human umbilical vein endothelial cells (HUVECs) tube formation but increased apoptosis and G1 arrest. Gene ontology enrichment analysis revealed that the enriched processes related to DPYSL3 overexpression in UC were tissue morphogenesis, cell mesenchyme migration, smooth muscle regulation, metabolic processes, and RNA processing. In vivo study revealed DPYSL3 knockdown in UC tumours significantly suppressed the growth of tumours and decreased MYC and GLUT1 protein expression.

CONCLUSIONS

DPYSL3 promotes the aggressiveness of UC cells by changing their biological behaviours and is likely associated with cytoskeletal and metabolic process modifications. Furthermore, DPYSL3 protein overexpression in UC was associated with aggressive clinicopathological characteristics and independently predicted poor clinical outcomes. Therefore, DPYSL3 can be used as a novel therapeutic target for UC.

Extracellular alkaline pH enhances migratory behaviors of hepatocellular carcinoma cells as a caution against the indiscriminate application of alkalinizing drug therapy: In vitro microscopic studies

The migratory process is a highly organized, differentiated, and polarized stage by which many signaling pathways are regulated to control cell migration. Since the significant evidence of migrating cells is the reorganization of the cytoskeleton. In the recent study, the cell migration model was assessed on the fact that any disruption obtained in the cellular monolayer confluent, may cause stimulation for surrounding cells to migrate. We attempt to demonstrate the morphological alterations associated with these migrating cells. In this case, sterilized 1 N NaOH (1 µl) was used as alkaline burnt. It leads to scratching the monolayer of hepatocellular carcinoma (HLF cell line) allowing cells to lose their connection. Scanning electron microscopy (SEM), fluorescence microscopy, light inverted microscopy, and dark field were used for discovering the morphological alterations associated with migrating cancer cells. The findings show that cells exhibited distinctive alterations including a polarizing stage, accumulation of the actin nodules in front of the nucleus, and protrusions. Nuclei appeared as lobulated shapes during migration. Lamellipodia and uropod were extended as well. Additionally, TGFβ1 proved its expression in HLF and SNU449 after their stimulation. It is demonstrated that hepatocellular carcinoma cells can migrate after their stimulation and there is a caution against the indiscriminate application of alkalinizing drug therapy.

Inactivation of PTEN and ZFHX3 in Mammary Epithelial Cells Alters Patterns of Collective Cell Migration

Whole exome sequencing of invasive mammary carcinomas revealed the association of mutations in PTEN and ZFHX3 tumor suppressor genes (TSGs). We generated single and combined PTEN and ZFHX3 knock-outs (KOs) in the immortalized mammary epithelial cell line MCF10A to study the role of these genes and their potential synergy in migration regulation. Inactivation of PTEN, but not ZFHX3, induced the formation of large colonies in soft agar. ZFHX3 inactivation in PTEN KO, however, increased colony numbers and normalized their size. Cell migration was affected in different ways upon PTEN and ZFHX3 KO. Inactivation of PTEN enhanced coordinated cell motility and thus, the collective migration of epithelial islets and wound healing. In contrast, ZFHX3 knockout resulted in the acquisition of uncoordinated cell movement associated with the appearance of immature adhesive junctions (AJs) and the increased expression of the mesenchymal marker vimentin. Inactivation of the two TSGs thus induces different stages of partial epithelial-to-mesenchymal transitions (EMT). Upon double KO (DKO), cells displayed still another motile state, characterized by a decreased coordination in collective migration and high levels of vimentin but a restoration of mature linear AJs. This study illustrates the plasticity of migration modes of mammary cells transformed by a combination of cancer-associated genes.

How does plasticity of migration help tumor cells to avoid treatment: Cytoskeletal regulators and potential markers

Tumor shrinkage as a result of antitumor therapy is not the only and sufficient indicator of treatment success. Cancer progression leads to dissemination of tumor cells and formation of metastases - secondary tumor lesions in distant organs. Metastasis is associated with acquisition of mobile phenotype by tumor cells as a result of epithelial-to-mesenchymal transition and further cell migration based on cytoskeleton reorganization. The main mechanisms of individual cell migration are either mesenchymal, which depends on the activity of small GTPase Rac, actin polymerization, formation of adhesions with extracellular matrix and activity of proteolytic enzymes or amoeboid, which is based on the increase in intracellular pressure caused by the enhancement of actin cortex contractility regulated by Rho-ROCK-MLCKII pathway, and does not depend on the formation of adhesive structures with the matrix, nor on the activity of proteases. The ability of tumor cells to switch from one motility mode to another depending on cell context and environmental conditions, termed migratory plasticity, contributes to the efficiency of dissemination and often allows the cells to avoid the applied treatment. The search for new therapeutic targets among cytoskeletal proteins offers an opportunity to directly influence cell migration. For successful treatment it is important to assess the likelihood of migratory plasticity in a particular tumor. Therefore, the search for specific markers that can indicate a high probability of migratory plasticity is very important.

KIF17 maintains the epithelial phenotype of breast cancer cells and curbs tumour metastasis

Kinesin superfamily motor protein 17 (KIF17) was previously identified downregulated in breast cancer and correlated with patient prognosis. However, its pathophysiological role in tumours remains unknown. Here, we confirmed that KIF17 was significantly under-expressed in breast cancer tissues and low KIF17 expression correlated with poor outcomes in patients with breast cancer. In vitro and in vivo experiments demonstrated that KIF17 overexpression in breast cancer cell lines significantly inhibited breast cancer invasion and metastasis. By establishing the lung metastatic MDA-MB-231 cell lines, we found a transient silence of KIF17 during the initiation of breast cancer metastasis. Further experiments revealed that KIF17 might suppress metastasis by regulating the level of acetylated tubulin to maintain cytoskeleton stability. Eventually, we found that the low expression of KIF17 in breast cancer is regulated by DNMT1-mediated 5-mC DNA methylation and epigenetic silencing. Decitabine can effectively improve the expression level of KIF17 in breast cancer cells. Our study demonstrates that KIF17 mediates microtubule acetylation to maintain the stability of microtubules, thereby inhibiting tumour invasion and metastasis.

Molecular neuropathology of brain-invasive meningiomas

Invasion of brain tissue by meningiomas has been identified as one key factor for meningioma recurrence. The identification of meningioma tumor tissue surrounded by brain tissue in neurosurgical samples has been touted as a criterion for atypical meningioma (CNS WHO grade 2), but is only rarely seen in the absence of other high-grade features, with brain-invasive otherwise benign (BIOB) meningiomas remaining controversial. While post-surgery irradiation therapy might be initiated in brain-invasive meningiomas to prevent recurrences, specific treatment approaches targeting key molecules involved in the invasive process are not established. Here we have compiled the current knowledge about mechanisms supporting brain tissue invasion by meningiomas and summarize preclinical models studying targeted therapies with potential inhibitory effects.

Modulation of Biological Responses of Tumor Cells Adhered to Poly(2-methoxyethyl acrylate) with Increasing Cell Viability under Serum-Free Conditions

Circulating tumor cells in body fluids are important biomarkers in cancer diagnosis. The culture of tumor cells isolated from body fluids can provide intrinsic information about tumors and can be used to screen for the best anticancer drugs. However, the culture of primary tumor cells has been hindered by their low viability and difficulties in recapitulating the phenotype of primary tumors in in vitro culture. The culture of tumor cells under serum-free conditions is one of the methodologies to maintain the phenotype and genotype of primary tumors. Poly(2-methoxyethyl acrylate) (PMEA)-coated substrates have been investigated to prolong the proliferation of tumor cells under serum-free conditions. In this study, we investigated the detailed behavior and the mechanism of the increase in tumor cell viability after adherence to PMEA substrates. The blebbing formation of tumor cells on PMEA was attributed not to apoptosis but to the low adhesion strength of cells on PMEA. Moreover, blebbing tumor cells showed amoeboid movement and formed clusters with other cells via N-cadherin, leading to an increase in tumor cell viability. Furthermore, the behaviors of tumor cells adhered to PMEA under serum-free conditions were involved in the activation of the PI3K and Rho-associated protein kinase pathways. Thus, we propose that PMEA would be suitable for the development of devices to cultivate primary tumor cells under serum-free conditions for the label-free diagnosis of cancer.

Dual role of E-cadherin in cancer cells

E-cadherin is the main component of epithelial adherens junctions (AJs), which play a crucial role in the maintenance of stable cell-cell adhesion and overall tissue integrity. Down-regulation of E-cadherin expression has been found in many carcinomas, and loss of E-cadherin is generally associated with poor prognosis in patients. During the last decade, however, numerous studies have shown that E-cadherin is essential for several aspects of cancer cell biology that contribute to cancer progression, most importantly, active cell migration. In this review, we summarize the available data about the input of E-cadherin in cancer progression, focusing on the latest advances in the research of the various roles E-cadherin-based AJs play in cancer cell dissemination. The review also touches upon the "cadherin switching" in cancer cells where N- or P-cadherin replace or are co-expressed with E-cadherin and its influence on the migratory properties of cancer cells.

Lysine 2-hydroxyisobutyrylation proteomics reveals protein modification alteration in the actin cytoskeleton pathway of oral squamous cell carcinoma

As the most commonplace malignant carcinoma in the oral cavity, oral squamous cell carcinoma (OSCC) is highly invasive and prone to recurrence. The nosogenesis of OSCC are affected by epigenetics. Recently, a newly-found post-translational modification of lysine, 2-hydroxyisobutylation (Khib), has been proved to play a critical role in biological regulation. However, no research has evaluated the mechanism of Khib in oral cancer. Here, we performed liquid chromatography-mass spectrometry-based quantitative proteomics combined with bioinformatics analysis to reveal and evaluate Khib protein alterations in OSCC. Numerous proteins in OSCC undergo up-regulated modification of Khib. We quantified and identified 967 proteins with differential expression levels, and 617 2-hydroxyisobutylated proteins with 938 Khib sites. Among them, 125 proteins both differentially expressed and accompanied by obvious Khib modification were further identified and analyzed through KEGG-based and ingenuity pathway analysis (IPA). These proteins are enriched in the actin cytoskeleton regulatory pathway, and IPA predicted that they alter the state of actin aggregation and stability, hence impacting and regulating the actin cytoskeleton in OSCC. This is the first 2-hydroxyisobutylated modification proteomics performed for OSCC. Khib protein is significantly concentrated in the actin cytoskeleton regulatory pathway, indicating that this pathway may mediate the tumorigenesis or exacerbation of OSCC. SIGNIFICANCE: This is the first study that revealed the alterations of Khib protein in oral squamous cell carcinoma through LC-MS/MS-based modified proteomic. Our data showed that the protein in the actin cytoskeleton regulatory pathway was underwent significant Khib modification and abundance changes. We applied predictive function in IPA software to analyze and clarify that the aggregation of actin and the regulation of actin stability that mediated by the actin cytoskeleton regulatory pathway may be the potential mechanism of the occurrence and development of oral squamous cell carcinoma. Our research broadens the understanding of the pathogenesis of oral squamous cell carcinoma and provides new insights for future research.

Screening and cellular validation of prognostic genes regulated by super enhancers in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the leading cause of death in patients with head and neck cancer. Reliable biomarkers to guide treatment decisions for OSCC remain scarce. The purpose of this study was to identify novel prognostic markers regulated by super enhancers in OSCC. Eight modules were obtained by weighted gene co-expression network analysis (WGCNA), among which MEblue module had the highest correlation with tumor stage, alcohol consumption and smoking. There were 41 genes regulated by super enhancers in MEblue module. Functional analysis showed that 41 super enhancer-regulated genes were involved in cancer progression. A total of twenty transcription factors of the 41 genes were predicted. Prognostic analysis of the 41 genes and the top 5 transcription factors showed that patients with high expression of AHCY, KCMF1, MANBAL and TFDP1 had a poor prognosis. Immunohistochemical analysis showed that AHCY, KCMF1 and MANBAL were highly expressed in OSCC tissue. Cellular experiment demonstrated that TFDP1 promoted AHCY, KCMF1 and MANBAL expression by binding to the super enhancers of these genes. Knockdown of TFDP1, AHCY, KCMF1 and MANBAL inhibited the proliferation of OSCC cells. In conclusion, AHCY, KCMF1 and MANBAL were recognized as super enhancer-regulated prognostic biomarkers regulated by TFDP1 in OSCC.

Two Motors and One Spring: Hypothetic Roles of Non-Muscle Myosin II and Submembrane Actin-Based Cytoskeleton in Cell Volume Sensing

Changes in plasma membrane curvature and intracellular ionic strength are two key features of cell volume perturbations. In this hypothesis we present a model of the responsible molecular apparatus which is assembled of two molecular motors [non-muscle myosin II (NMMII) and protrusive actin polymerization], a spring [a complex between the plasma membrane (PM) and the submembrane actin-based cytoskeleton (smACSK) which behaves like a viscoelastic solid] and the associated signaling proteins. We hypothesize that this apparatus senses changes in both the plasma membrane curvature and the ionic strength and in turn activates signaling pathways responsible for regulatory volume increase (RVI) and regulatory volume decrease (RVD). During cell volume changes hydrostatic pressure (HP) changes drive alterations in the cell membrane curvature. HP difference has opposite directions in swelling versus shrinkage, thus allowing distinction between them. By analogy with actomyosin contractility that appears to sense stiffness of the extracellular matrix we propose that NMMII and actin polymerization can actively probe the transmembrane gradient in HP. Furthermore, NMMII and protein-protein interactions in the actin cortex are sensitive to ionic strength. Emerging data on direct binding to and regulating activities of transmembrane mechanosensors by NMMII and actin cortex provide routes for signal transduction from transmembrane mechanosensors to cell volume regulatory mechanisms.