Lamellipodia and filopodia in metastasis and invasion

CYRI controls epidermal wound closure and cohesion of invasive border cell cluster in Drosophila

Cell motility is crucial for many biological processes including morphogenesis, wound healing, and cancer invasion. The WAVE regulatory complex (WRC) is a central Arp2/3 regulator driving cell motility downstream of activation by Rac GTPase. CYFIP-related Rac1 interactor (CYRI) proteins are thought to compete with WRC for interaction with Rac1 in a feedback loop regulating lamellipodia dynamics. However, the physiological role of CYRI proteins in vivo in healthy tissues is unclear. Here, we used Drosophila as a model system to study CYRI function at the cellular and organismal levels. We found that CYRI is not only a potent WRC regulator in single macrophages that controls lamellipodial spreading but also identified CYRI as a molecular brake on the Rac-WRC-Arp2/3 pathway to slow down epidermal wound healing. In addition, we found that CYRI limits invasive border cell migration by controlling cluster cohesion and migration. Thus, our data highlight CYRI as an important regulator of cellular and epithelial tissue dynamics conserved across species.

Combinatorial effects of cannabinoid receptor 1 and 2 agonists on characteristics and proteomic alteration in MDA-MB-231 breast cancer cells

Breast cancer is the most common cancer diagnosed in women worldwide. However, the effective treatment for breast cancer progression is still being sought. The activation of cannabinoid receptor (CB) has been shown to negatively affect breast cancer cell survival. Our previous study also reported that breast cancer cells responded to various combinations of CB1 and CB2 agonists differently. Nonetheless, the mechanism underlying this effect and whether this phenomenon can be seen in other cancer characteristics remain unknown. Therefore, this study aims to further elucidate the effects of highly selective CB agonists and their combination on triple-negative breast cancer proliferation, cell cycle progression, invasion, lamellipodia formation as well as proteomic profile of MDA-MB-231 breast cancer cells. The presence of CB agonists, specifically a 2:1 (ACEA: GW405833) combination, prominently inhibited colony formation and induced the S-phase cell cycle arrest in MDA-MB-231 cells. Furthermore, cell invasion ability and lamellipodia formation of MDA-MB-231 were also attenuated by the exposure of CB agonists and their 2:1 combination ratio. Our proteomic analysis revealed proteomic profile alteration in MDA-MB-231 upon CB exposure that potentially led to breast cancer suppression, such as ZPR1/SHC1/MAPK-mediated cell proliferation and AXL/VAV2/RAC1-mediated cell motility pathways. Our findings showed that selective CB agonists and their combination suppressed breast cancer characteristics in MDA-MB-231 cells. The exposure of CB agonists also altered the proteomic profile of MDA-MB-231, which could lead to cell proliferation and motility suppression.

Role of a novel uropod-like cell membrane protrusion in the pathogenesis of the parasite Trichomonas vaginalis

Trichomonas vaginalis causes trichomoniasis, the most common non-viral sexually transmitted disease worldwide. As an extracellular parasite, adhesion to host cells is essential for the development of infection. During attachment, the parasite changes its tear ovoid shape to a flat ameboid form, expanding the contact surface and migrating through tissues. Here, we have identified a novel structure formed at the posterior pole of adherent parasite strains, resembling the previously described uropod, which appears to play a pivotal role as an anchor during the attachment process. Moreover, our research demonstrates that the overexpression of the tetraspanin T. vaginalis TSP5 protein (TvTSP5), which is localized on the cell surface of the parasite, notably enhances the formation of this posterior anchor structure in adherent strains. Finally, we demonstrate that parasites that overexpress TvTSP5 possess an increased ability to adhere to host cells, enhanced aggregation and reduced migration on agar plates. Overall, these findings unveil novel proteins and structures involved in the intricate mechanisms of T. vaginalis interactions with host cells.

Breast Cancer Cells Exhibit Mesenchymal-Epithelial Plasticity Following Dynamic Modulation of Matrix Stiffness

Mesenchymal-epithelial transition (MET) is essential for tissue and organ development and is thought to contribute to cancer by enabling the establishment of metastatic lesions. Despite its importance in both health and disease, there is a lack of in vitro platforms to study MET and little is known about the regulation of MET by mechanical cues. Here, hyaluronic acid-based hydrogels with dynamic and tunable stiffnesses mimicking that of normal and tumorigenic mammary tissue are synthesized. The platform is then utilized to examine the response of mammary epithelial cells and breast cancer cells to dynamic modulation of matrix stiffness. Gradual softening of the hydrogels reduces proliferation and increases apoptosis of breast cancer cells. Moreover, breast cancer cells exhibit temporal changes in cell morphology, cytoskeletal organization, and gene expression that are consistent with mesenchymal-epithelial plasticity as the stiffness of the matrix is reduced. A reduction in matrix stiffness attenuates the expression of integrin-linked kinase, and inhibition of integrin-linked kinase impacts proliferation, apoptosis, and gene expression in cells cultured on stiff and dynamic hydrogels. Overall, these findings reveal intermediate epithelial/mesenchymal states as cells move along a matrix stiffness-mediated MET trajectory and suggest an important role for matrix mechanics in regulating mesenchymal-epithelial plasticity.

p300 KAT Regulates SOX10 Stability and Function in Human Melanoma

SOX10 is a lineage-specific transcription factor critical for melanoma tumor growth; on the other hand, SOX10 loss-of-function drives the emergence of therapy-resistant, invasive melanoma phenotypes. A major challenge has been developing therapeutic strategies targeting SOX10's role in melanoma proliferation while preventing a concomitant increase in tumor cell invasion. In this study, we report that the lysine acetyltransferase (KAT) EP300 and SOX10 gene loci on chromosome 22 are frequently co-amplified in melanomas, including UV-associated and acral tumors. We further show that p300 KAT activity mediates SOX10 protein stability and that the p300 inhibitor A-485 downregulates SOX10 protein levels in melanoma cells via proteasome-mediated degradation. Additionally, A-485 potently inhibits proliferation of SOX10+ melanoma cells while decreasing invasion in AXLhigh/MITFlow melanoma cells through downregulation of metastasis-related genes. We conclude that the SOX10/p300 axis is critical to melanoma growth and invasion and that inhibition of p300 KAT activity through A-485 may be a worthwhile therapeutic approach for SOX10-reliant tumors.

SIGNIFICANCE

The p300 KAT inhibitor A-485 blocks SOX10-dependent proliferation and SOX10-independent invasion in hard-to-treat melanoma cells.

Quantification of membrane geometry and protein sorting on cell membrane protrusions using fluorescence microscopy

Plasma membranes are flexible and can exhibit numerous shapes below the optical diffraction limit. The shape of cell periphery can either induce or be a product of local protein density changes, encoding numerous cellular functions. However, quantifying membrane curvature and the ensuing sorting of proteins in live cells remains technically demanding. Here, we demonstrate the use of simple widefield fluorescence microscopy to study the geometrical properties (i.e., radius, length, and number) of thin membrane protrusions. Importantly, the quantification of protrusion radius establishes a platform for studying the curvature preferences of membrane proteins.

Dynamically Mapping the Topography and Stiffness of the Leading Edge of Migrating Cells Using AFM in Fast-QI Mode

Cell migration profoundly influences cellular function, often resulting in adverse effects in various pathologies including cancer metastasis. Directly assessing and quantifying the nanoscale dynamics of living cell structure and mechanics has remained a challenge. At the forefront of cell movement, the flat actin modules─the lamellipodium and the lamellum─interact to propel cell migration. The lamellipodium extends from the lamellum and undergoes rapid changes within seconds, making measurement of its stiffness a persistent hurdle. In this study, we introduce the fast-quantitative imaging (fast-QI) mode, demonstrating its capability to simultaneously map both the lamellipodium and the lamellum with enhanced spatiotemporal resolution compared with the classic quantitative imaging (QI) mode. Specifically, our findings reveal nanoscale stiffness gradients in the lamellipodium at the leading edge, where it appears to be slightly thinner and significantly softer than the lamellum. Additionally, we illustrate the fast-QI mode's accuracy in generating maps of height and effective stiffness through a streamlined and efficient processing of force-distance curves. These results underscore the potential of the fast-QI mode for investigating the role of motile cell structures in mechanosensing.

p300 KAT regulates SOX10 stability and function in human melanoma

SOX10 is a lineage-specific transcription factor critical for melanoma tumor growth, while SOX10 loss-of-function drives the emergence of therapy-resistant, invasive melanoma phenotypes. A major challenge has been developing therapeutic strategies targeting SOX10's role in melanoma proliferation, while preventing a concomitant increase in tumor cell invasion. Here, we report that the lysine acetyltransferase (KAT) EP300 and SOX10 gene loci on Chromosome 22 are frequently co-amplified in melanomas, including UV-associated and acral tumors. We further show that p300 KAT activity mediates SOX10 protein stability and that the p300 inhibitor, A-485, downregulates SOX10 protein levels in melanoma cells via proteasome-mediated degradation. Additionally, A-485 potently inhibits proliferation of SOX10+ melanoma cells while decreasing invasion in AXLhigh/MITFlow melanoma cells through downregulation of metastasis-related genes. We conclude that the SOX10/p300 axis is critical to melanoma growth and invasion, and that inhibition of p300 KAT activity through A-485 may be a worthwhile therapeutic approach for SOX10-reliant tumors.

Electrospun polydioxanone/fucoidan blend nanofibers loaded with anti-cancer precipitate from Jaspis diastra and paclitaxel: Physico-chemical characterization and in-vitro screening

Nanofibers for drug delivery systems have gained much attention during the past years. This paper describes for the first time the loading of a bioactive precipitate (JAD) from the marine sponge Jaspis diastra in PDX and fucoidan-PDX. JAD was characterized by LC-MS/MS and the major component was jaspamide (1) with a purity of 62.66 %. The cytotoxicity of JAD was compared with paclitaxel (PTX). JAD and PTX displayed IC50 values of 1.10 ± 0.7 μg/mL and 0.21 ± 0.12 μg/mL on skin fibroblasts L929 cells whilst their IC50 values on uveal MP41 cancer cells, were 2.10 ± 0.55 μg/mL and 1.38 ± 0.68 μg/mL, respectively. JAD was found to be less cytotoxic to healthy fibroblasts compared to PTX. JAD and PTX loaded scaffolds showed sustained release over 96 h in physiological medium which is likely to reduce the secondary cytotoxic effect induced by JAD and PTX alone. The physico-chemical properties of the loaded and unloaded scaffolds together with their degradation and action on tumor microenvironment by using L929 and MP41 cells were investigated. JAD and PTX at a concentration of 0.5 % (drug/polymer, w/w) in the electrospun mats prevented growth and proliferation of L929 and MP41 cells. Co-culture of L929 and MP41 showed that the JAD and PTX loaded mats inhibited the growth of both cells and caused cell death.

Glycogen synthase kinase 3β: the nexus of chemoresistance, invasive capacity, and cancer stemness in pancreatic cancer

The treatment of pancreatic cancer remains a significant clinical challenge due to the limited number of patients eligible for curative (R0) surgery, failures in the clinical development of targeted and immune therapies, and the pervasive acquisition of chemotherapeutic resistance. Refractory pancreatic cancer is typified by high invasiveness and resistance to therapy, with both attributes related to tumor cell stemness. These malignant characteristics mutually enhance each other, leading to rapid cancer progression. Over the past two decades, numerous studies have produced evidence of the pivotal role of glycogen synthase kinase (GSK)3β in the progression of over 25 different cancer types, including pancreatic cancer. In this review, we synthesize the current knowledge on the pathological roles of aberrant GSK3β in supporting tumor cell proliferation and invasion, as well as its contribution to gemcitabine resistance in pancreatic cancer. Importantly, we discuss the central role of GSK3β as a molecular hub that mechanistically connects chemoresistance, tumor cell invasion, and stemness in pancreatic cancer. We also discuss the involvement of GSK3β in the formation of desmoplastic tumor stroma and in promoting anti-cancer immune evasion, both of which constitute major obstacles to successful cancer treatment. Overall, GSK3β has characteristics of a promising therapeutic target to overcome chemoresistance in pancreatic cancer.

NeuM: A Neuron-Selective Probe Incorporates into Live Neuronal Membranes via Enhanced Clathrin-Mediated Endocytosis in Primary Neurons

The development of a small-molecule probe designed to selectively target neurons would enhance the exploration of intricate neuronal structures and functions. Among such probes, NeuO stands out as the pioneer and has gained significant traction in the field of research. Nevertheless, neither the mechanism behind neuron-selectivity nor the cellular localization has been determined. Here, we introduce NeuM, a derivative of NeuO, designed to target neuronal cell membranes. Furthermore, we elucidate the mechanism behind the selective neuronal membrane trafficking that distinguishes neurons. In an aqueous buffer, NeuM autonomously assembles into micellar structures, leading to the quenching of its fluorescence (Φ=0.001). Upon exposure to neurons, NeuM micelles were selectively internalized into neuronal endosomes via clathrin-mediated endocytosis. Through the endocytic recycling pathway, NeuM micelles integrate into neuronal membrane, dispersing fluorescent NeuM molecules in the membrane (Φ=0.61). Molecular dynamics simulations demonstrated that NeuM, in comparison to NeuO, possesses optimal lipophilicity and molecular length, facilitating its stable incorporation into phospholipid layers. The stable integration of NeuM within neuronal membrane allows the prolonged monitoring of neurons, as well as the visualization of intricate neuronal structures.

Fascin - F-actin interaction studied by molecular dynamics simulation and protein network analysis

Actin bundles are an important component of cellular cytoskeleton and participate in the movement of cells. The formation of actin bundles requires the participation of many actin binding proteins (ABPs). Fascin is a member of ABPs, which plays a key role in bundling filamentous actin (F-actin) to bundles. However, the detailed interactions between fascin and F-actin are unclear. In this study, we construct an atomic-level structure of fascin - F-actin complex based on a rather poor cryo-EM data with resolution of 20 nm. We first optimized the geometries of the complex by molecular dynamics (MD) simulation and analyzed the binding site and pose of fascin which bundles two F-actin chains. Next, binding free energy of fascin was calculated by MM/GBSA method. Finally, protein structure network analysis (PSNs) was performed to analyze the key residues for fascin binding. Our results show that residues of K22, E27, E29, K41, K43, R110, R149, K358, R408 and K471 on fascin are important for its bundling, which are in good agreement with the experimental data. On the other hand, the consistent results indicate that the atomic-level model of fascin - F-actin complex is reliable. In short, this model can be used to understand the detailed interactions between fascin and F-actin, and to develop novel potential drugs targeting fascin.Communicated by Ramaswamy H. Sarma.

Tunneling Nanotubes: The Cables for Viral Spread and Beyond

Multicellular organisms require cell-to-cell communication to maintain homeostasis and thrive. For cells to communicate, a network of filamentous, actin-rich tunneling nanotubes (TNTs) plays a pivotal role in facilitating efficient cell-to-cell communication by connecting the cytoplasm of adjacent or distant cells. Substantial documentation indicates that diverse cell types employ TNTs in a sophisticated and intricately organized fashion for both long and short-distance communication. Paradoxically, several pathogens, including viruses, exploit the structural integrity of TNTs to facilitate viral entry and rapid cell-to-cell spread. These pathogens utilize a "surfing" mechanism or intracellular transport along TNTs to bypass high-traffic cellular regions and evade immune surveillance and neutralization. Although TNTs are present across various cell types in healthy tissue, their magnitude is increased in the presence of viruses. This heightened induction significantly amplifies the role of TNTs in exacerbating disease manifestations, severity, and subsequent complications. Despite significant advancements in TNT research within the realm of infectious diseases, further studies are imperative to gain a precise understanding of TNTs' roles in diverse pathological conditions. Such investigations are essential for the development of novel therapeutic strategies aimed at leveraging TNT-associated mechanisms for clinical applications. In this chapter, we emphasize the significance of TNTs in the life cycle of viruses, showcasing the potential for a targeted approach to impede virus-host cell interactions during the initial stages of viral infections. This approach holds promise for intervention and prevention strategies.

Structure and function of the membrane microdomains in osteoclasts

The cell membrane structure is closely related to the occurrence and progression of many metabolic bone diseases observed in the clinic and is an important target to the development of therapeutic strategies for these diseases. Strong experimental evidence supports the existence of membrane microdomains in osteoclasts (OCs). However, the potential membrane microdomains and the crucial mechanisms underlying their roles in OCs have not been fully characterized. Membrane microdomain components, such as scaffolding proteins and the actin cytoskeleton, as well as the roles of individual membrane proteins, need to be elucidated. In this review, we discuss the compositions and critical functions of membrane microdomains that determine the biological behavior of OCs through the three main stages of the OC life cycle.

Durotaxis and negative durotaxis: where should cells go?

Durotaxis and negative durotaxis are processes in which cell migration is directed by extracellular stiffness. Durotaxis is the tendency of cells to migrate toward stiffer areas, while negative durotaxis occurs when cells migrate toward regions with lower stiffness. The mechanisms of both processes are not yet fully understood. Additionally, the connection between durotaxis and negative durotaxis remains unclear. In this review, we compare the mechanisms underlying durotaxis and negative durotaxis, summarize the basic principles of both, discuss the possible reasons why some cell types exhibit durotaxis while others exhibit negative durotaxis, propose mechanisms of switching between these processes, and emphasize the challenges in the investigation of durotaxis and negative durotaxis.

Microfluidic single-cell migration chip reveals insights into the impact of extracellular matrices on cell movement

Cell migration is a complex process that plays a crucial role in normal physiology and pathologies such as cancer, autoimmune diseases, and mental disorders. Conventional cell migration assays face limitations in tracking a large number of individual migrating cells. To address this challenge, we have developed a high-throughput microfluidic cell migration chip, which seamlessly integrates robotic liquid handling and computer vision to swiftly monitor the movement of 3200 individual cells, providing unparalleled single-cell resolution for discerning distinct behaviors of the fast-moving cell population. This study focuses on the ECM's role in regulating cellular migration, utilizing this cutting-edge microfluidic technology to investigate the impact of ten different ECMs on triple-negative breast cancer cell lines. We found that collagen IV, collagen III, and collagen I coatings were the top enhancers of cell movement. Combining these ECMs increased cell motility, but the effect was sub-additive. Furthermore, we examined 87 compounds and found that while some compounds inhibited migration on all substrates, significantly distinct effects on differently coated substrates were observed, underscoring the importance of considering ECM coating. We also utilized cells expressing a fluorescent actin reporter and observed distinct actin structures in ECM-interacting cells. ScRNA-Seq analysis revealed that ECM coatings induced EMT and enhanced cell migration. Finally, we identified genes that were particularly up-regulated by collagen IV and the selective inhibitors successfully blocked cell migration on collagen IV. Overall, the study provides insights into the impact of various ECMs on cell migration and dynamics of cell movement with implications for developing therapeutic strategies to combat diseases related to cell motility.

Inhibition of Phagocytosis by Silibinin in Mouse Macrophages

This study investigated the effects of silibinin, derived from milk thistle (Silybum marianum), on lipopolysaccharide (LPS)-induced morphological changes in mouse macrophages. Silibinin was treated at various doses and time points to assess its effects on macrophage activation, including morphological changes and phagocytosis. Silibinin effectively inhibited LPS-induced pseudopodia formation and size increase, while unstimulated cells remained round. Silibinin's impact on phagocytosis was dose- and time-dependent, showing a decrease. We explored its mechanism of action on kinases using a MAPK array. Among the three MAPK family members tested, silibinin had a limited effect on JNK and p38 but significantly inhibited ERK1/2 and related RSK1/2. Silibinin also inhibited MKK6, AKT3, MSK2, p70S6K, and GSK-3β. These findings highlight silibinin's potent inhibitory effects on phagocytosis and morphological changes in macrophages. We suggest its potential as an anti-inflammatory agent due to its ability to target key inflammatory pathways involving ERK1/2 and related kinases. Overall, this study demonstrates the promising therapeutic properties of silibinin in modulating macrophage function and inflammation.

CD44s-activated tPA/LRP1-NFκB pathway drives lamellipodia outgrowth in luminal-type breast cancer cells

Some cancer cells migration and metastasis are characterized by the outgrowth of lamellipodia protrusions in which the underlying mechanism remains unclear. Evidence has confirmed that lamellipodia formation could be regulated by various adhesion molecules, such as CD44, and we previously reported that lamellipodia at the leading edge of luminal type breast cancer (BrCa) were enriched with high expression of CD44. In this study, we found that the overexpression of CD44s could promote lamellipodia formation in BrCa cells through inducing tissue type plasminogen activator (tPA) upregulation, which was achieved by PI3K/Akt signaling pathway activation. Moreover, we revealed that tPA could interact with LDL receptor related protein 1 (LRP1) to activate the downstream NFκB signaling pathway, which in turn facilitate lamellipodia formation. Notably, inhibition of the tPA/LRP1-NFkB signaling cascade could attenuate the CD44s-induced lamellipodia formation. Thus, our findings uncover a novel role of CD44s in driving lamellipodia outgrowth through tPA/LRP1-NFkB axis in luminal BrCa cells that may be helpful for seeking potential therapeutic targets.

A mechanistic insight into the potential anti-cancerous property of Nigella sativa on breast cancer through micro-RNA regulation: An in vitro & in vivo study

Cancer continues to threat mortal alongside scientific community with burgeoning grasp. Most efforts directed to tame Cancer such as radiotherapy or chemotherapy, all came at a cost of severe side effects. The plant derived bioactive compounds on the other hand carries an inevitable advantage of being safer, bioavailable & less toxic compared to contemporary chemotherapeutics. Our strategic approach employed solvent extraction of Black Seed Oil (BSO) to highlight the orchestrated use of its oil soluble phytochemicals - Thymoquinone, Carvacrol & Trans-Anethole when used in cohort. These anti-cancer agents in unbelievably modest amounts present in BSO shows better potential to delineate migratory properties in breast cancer cells as compared to when treated individually. BSO was also observed to have apoptotic calibre when investigated in MDA-MB-231 and MCF-7 cell lines. We performed chemical characterization of the individual phytochemical as well as the oil in-whole to demonstrate the bioactive oil-soluble entities present in whole extract. BSO was observed to have significant anti-cancerous properties in cumulative proportion that is reportedly higher than the individual three components. Besides, this study also reports micro-RNA regulation on BSO administration, thereby playing a pivotal role in breast cancer alleviation. Thus, synergistic action of the integrants serves better combat force against breast cancer in the form of whole extract, hence aiming at a more lucrative paradigm while significantly regulating microRNAs associated with breast cancer migration and apoptosis.

Kinetic Effects of Transferrin-Conjugated Gold Nanoparticles on the Antioxidant Glutathione-Thioredoxin Pathway

Nanoparticle-based therapeutics are being clinically translated for treating cancer. Even when thought to be biocompatible, nanoparticles are being increasingly identified as altering cell regulation and homeostasis. Antioxidant pathways are important for maintaining cell redox homeostasis and play important roles by maintaining ROS levels within tolerable ranges. Here, we sought to understand how a model of a relatively inert nanoparticle without any therapeutic agent itself could antagonize a cancer cell lines' antioxidant mechanism. A label-free protein expression approach was used to assess the glutathione-thioredoxin antioxidative pathway in a prostate cancer cell line (PC-3) after exposure to gold nanoparticles conjugated with a targeting moiety (transferrin). The impact of the nanoparticles was also corroborated through morphological analysis with TEM and classification of pro-apoptotic cells by way of the sub-G0/G1 population via the cell cycle and annexin V apoptosis assay. After a two-hour exposure to nanoparticles, major proteins associated with the glutathione-thioredoxin antioxidant pathway were downregulated. However, this response was acute, and in terms of protein expression, cells quickly recovered within 24 h once nanoparticle exposure ceased. The impact on PRDX-family proteins appears as the most influential factor in how these nanoparticles induced an oxidative stress response in the PC-3 cells. An apparent adaptive response was observed if exposure to nanoparticles continued. Acute exposure was observed to have a detrimental effect on cell viability compared to continuously exposed cells. Nanoparticle effects on cell regulation likely provide a compounding therapeutic advantage under some circumstances, in addition to the action of any cytotoxic agents; however, any therapeutic advantage offered by nanoparticles themselves with regard to vulnerabilities specific to the glutathione-thioredoxin antioxidative pathway is highly temporal.

Molecular characteristics of microsatellite stable early-onset colorectal cancer as predictors of prognosis and immunotherapeutic response

The incidence of early-onset colorectal cancer (EO-CRC, in patients younger than 50) is increasing worldwide. The specific gene signatures in EO-CRC patients are largely unknown. Since EO-CRC with microsatellite instability is frequently associated with Lynch syndrome, we aimed to comprehensively characterize the tumor microenvironment (TME) and gene expression profiles of EO-CRC with microsatellite stable (MSS-EO-CRC). Here, we demonstrated that MSS-EO-CRC has a similar pattern of tumor-infiltrating immune cells, immunotherapeutic responses, consensus molecular subtypes, and prognosis as late-onset CRC with MSS (MSS-LO-CRC). 133 differential expressed genes were identified as unique gene signatures of MSS-EO-CRC. Moreover, we established a risk score, which was positively associated with PD-L1 expression and could reflect both the level of tumor-infiltrating immune cells and the prognosis of MSS-EO-CRC patients. Application of this score on the anti-PD-L1 treatment cohort demonstrated that the low-risk score group has significant therapeutic advantages and clinical benefits. In addition, candidate driver genes were identified in the different-sidedness of MSS-EO-CRC patients. Altogether, MSS-EO-CRC exhibits distinct molecular profiles that differ from MSS-LO-CRC even though they have a similar TME characterization and survival pattern. Our risk score appears to be robust enough to predict prognosis and immunotherapeutic response and therefore could help to optimize the treatment of MSS-EO-CRC.

p53 regulates the effects of DAPT on Rac1 activation and migration of non-small-cell lung cancer cells

The use of γ-secretase inhibitors to inhibit the activation of Notch receptors can effectively inhibit the malignant process of tumors. Here, we demonstrate that p53 can modulate the effect of DAPT (a γ-secretase inhibitor) on the activation of small GTPase Rac1, thereby affecting cell migration of non-small-cell lung cancer H1299 and A549 cells. After treatment with 20 μM DAPT, activation of Rac1 was increased in H1299 cells but not in A549 cells. We further found that the migration ability of H1299 cells was increased, whereas that of A549 cells was reduced. The effect of DAPT on H1299 migration was repressed by Rac1-T17N, a dominant inactivated mutant of Rac1. H1299 is a p53-deficient cell line. When p53 protein was overexpressed in H1299 cells with a pEGFP-p53 plasmid, DAPT treatment no longer activated Rac1 and increased migration ability. Moreover, DAPT promoted the migration of H1299 cells by increasing the activity of Rac1 through the non-canonical Notch pathway. Taken together, these results indicate that the expression of p53 protein in lung cancer cells regulates the effect of DAPT on cell migration by modulating the activation of Rac1, suggesting that p53 may affect the therapeutic effects of Notch inhibitors in lung cancer patients.

Vesicle-Associated Actin Assembly by Formins Promotes TGFβ-Induced ANGPTL4 Trafficking, Secretion and Cell Invasion

Vesicle trafficking has emerged as an important process driving tumor progression through various mechanisms. Transforming growth factor beta (TGFβ)-mediated secretion of Angiopoietin-like 4 (ANGPTL4) is important for cancer development. Here, Formin-like 2 (FMNL2) is identified to be necessary for ANGPTL4 trafficking and secretion in response to TGFβ. Protein kinase C (PKC)-dependent phosphorylation of FMNL2 downstream of TGFβ stimulation is required for cancer cell invasion as well as ANGPTL4 vesicle trafficking and secretion. Moreover, using super resolution microscopy, ANGPTL4 trafficking is actin-dependent with FMNL2 directly polymerizing actin at ANGPTL4-containing vesicles, which are associated with Rab8a and myosin Vb. This work uncovers a formin-controlled mechanism that transiently polymerizes actin directly at intracellular vesicles to facilitate their mobility. This mechanism may be important for the regulation of cancer cell metastasis and tumor progression.

Antimetastatic Properties of Prodigiosin and the BH3-Mimetic Obatoclax (GX15-070) in Melanoma

Metastasis is the primary cause of death in cancer patients. Many current chemotherapeutic agents only show cytotoxic, but not antimetastatic properties. This leads to a reduction in tumor size, but allows cancer cells to disseminate, which ultimately causes patient death. Therefore, novel anticancer compounds with both effects need to be developed. In this work, we analyze the antimetastatic properties of prodigiosin and obatoclax (GX15-070), anticancer drugs of the Prodiginines (PGs) family. We studied PGs' effects on cellular adhesion and morphology in the human primary and metastatic melanoma cell lines, SK-MEL-28 and SK-MEL-5, and in the murine melanoma cell line, B16F10A. Cell adhesion sharply decreased in the treated cells, and this was accompanied by a reduction in filopodia protrusions and a significant decrease in the number of focal-adhesion structures. Moreover, cell migration was assessed through the wound-healing assay and cell motility was severely inhibited after 24 h of treatment. To elucidate the molecular mechanisms involved, changes in metastasis-related genes were analyzed through a gene-expression array. Key genes related to cellular invasion, migration and chemoresistance were significantly down-regulated. Finally, an in vivo model of melanoma-induced lung metastasis was established and significant differences in lung tumors were observed in the obatoclax-treated mice. Altogether, these results describe, in depth, PGs' cellular antimetastatic effects and identify in vivo antimetastatic properties of Obatoclax.

The molecular mechanisms and therapeutic strategies of EMT in tumor progression and metastasis

Epithelial–mesenchymal transition (EMT) is an essential process in normal embryonic development and tissue regeneration. However, aberrant reactivation of EMT is associated with malignant properties of tumor cells during cancer progression and metastasis, including promoted migration and invasiveness, increased tumor stemness, and enhanced resistance to chemotherapy and immunotherapy. EMT is tightly regulated by a complex network which is orchestrated with several intrinsic and extrinsic factors, including multiple transcription factors, post-translational control, epigenetic modifications, and noncoding RNA-mediated regulation. In this review, we described the molecular mechanisms, signaling pathways, and the stages of tumorigenesis involved in the EMT process and discussed the dynamic non-binary process of EMT and its role in tumor metastasis. Finally, we summarized the challenges of chemotherapy and immunotherapy in EMT and proposed strategies for tumor therapy targeting EMT.

ATF2 loss promotes tumor invasion in colorectal cancer cells via upregulation of cancer driver TROP2

In cancer, the activating transcription factor 2 (ATF2) has pleiotropic functions in cellular responses to growth stimuli, damage, or inflammation. Due to only limited studies, the significance of ATF2 in colorectal cancer (CRC) is not well understood. We report that low ATF2 levels correlated with worse prognosis and tumor aggressiveness in CRC patients. NanoString gene expression and ChIP analysis confirmed trophoblast cell surface antigen 2 (TROP2) as a novel inhibitory ATF2 target gene. This inverse correlation was further observed in primary human tumor tissues. Immunostainings revealed that high intratumoral heterogeneity for ATF2 and TROP2 expression was sustained also in liver metastasis. Mechanistically, our in vitro data of CRISPR/Cas9-generated ATF2 knockout (KO) clones revealed that high TROP2 levels were critical for cell de-adhesion and increased cell migration without triggering EMT. TROP2 was enriched in filopodia and displaced Paxillin from adherens junctions. In vivo imaging, micro-computer tomography, and immunostainings verified that an ATF2^KO/TROP2^high status triggered tumor invasiveness in in vivo mouse and chicken xenograft models. In silico analysis provided direct support that ATF2^low/TROP2^high expression status defined high-risk CRC patients. Finally, our data demonstrate that ATF2 acts as a tumor suppressor by inhibiting the cancer driver TROP2. Therapeutic TROP2 targeting might prevent particularly the first steps in metastasis, i.e., the de-adhesion and invasion of colon cancer cells.

Reduced miR-371b-5p expression drives tumor progression via CSDE1/RAC1 regulation in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer; however, specific prognostic biomarkers have not yet been developed. In this study, we identified dysregulated microRNAs (miRNAs) in TNBC by profiling miRNA and mRNA expression. In patients with TNBC, miR-371b-5p expression was reduced, and miR-371b-5p overexpression significantly mitigated TNBC cell growth, migration, and invasion. In addition, we found that expression of cold shock domain-containing protein E1 (CSDE1), a direct target gene of miR-371b-5p, was upregulated in TNBC cells, and inhibition of CSDE1 expression alleviated TNBC cell growth by regulating RAC1 transcription. Mechanistically, CSDE1, phosphorylated C-terminal domain (p-CTD) of RNA polymerase II (RNAPII), and CDK7 form a complex, and downregulation of CSDE1 leads to weak interaction between RNAPII p-CTD and CDK7, resulting in a decrease in RNAPII p-CTD expression to reduce RAC1 transcript levels in CSDE1-deficient TNBC cells. Our data demonstrate that miR-371b-5p is a tumor-suppressive miRNA that regulates the CSDE1/Rac1 axis and could be a potential prognostic biomarker for TNBC.

New Insights into the Roles of lncRNAs as Modulators of Cytoskeleton Architecture and Their Implications in Cellular Homeostasis and in Tumorigenesis

The importance of the cytoskeleton not only in cell architecture but also as a pivotal element in the transduction of signals that mediate multiple biological processes has recently been highlighted. Broadly, the cytoskeleton consists of three types of structural proteins: (1) actin filaments, involved in establishing and maintaining cell shape and movement; (2) microtubules, necessary to support the different organelles and distribution of chromosomes during cell cycle; and (3) intermediate filaments, which have a mainly structural function showing specificity for the cell type where they are expressed. Interaction between these protein structures is essential for the cytoskeletal mesh to be functional. Furthermore, the cytoskeleton is subject to intense spatio-temporal regulation mediated by the assembly and disassembly of its components. Loss of cytoskeleton homeostasis and integrity of cell focal adhesion are hallmarks of several cancer types. Recently, many reports have pointed out that lncRNAs could be critical mediators in cellular homeostasis controlling dynamic structure and stability of the network formed by cytoskeletal structures, specifically in different types of carcinomas. In this review, we summarize current information available about the roles of lncRNAs as modulators of actin dependent cytoskeleton and their impact on cancer pathogenesis. Finally, we explore other examples of cytoskeletal lncRNAs currently unrelated to tumorigenesis, to illustrate knowledge about them.

PI3K/AKT Signaling Tips the Balance of Cytoskeletal Forces for Cancer Progression

The PI3K/AKT signaling pathway plays essential roles in multiple cellular processes, which include cell growth, survival, metabolism, and motility. In response to internal and external stimuli, the PI3K/AKT signaling pathway co-opts other signaling pathways, cellular components, and cytoskeletal proteins to reshape individual cells. The cytoskeletal network comprises three main components, which are namely the microfilaments, microtubules, and intermediate filaments. Collectively, they are essential for many fundamental structures and cellular processes. In cancer, aberrant activation of the PI3K/AKT signaling cascade and alteration of cytoskeletal structures have been observed to be highly prevalent, and eventually contribute to many cancer hallmarks. Due to their critical roles in tumor progression, pharmacological agents targeting PI3K/AKT, along with cytoskeletal components, have been developed for better intervention strategies against cancer. In our review, we first discuss existing evidence in-depth and then build on recent advances to propose new directions for therapeutic intervention.

Cytoskeletal dynamics regulates stromal invasion behavior of distinct liver cancer subtypes

Drug treatment against liver cancer has limited efficacy due to heterogeneous response among liver cancer subtypes. In addition, the functional biophysical phenotypes which arise from this heterogeneity and contribute to aggressive invasive behavior remain poorly understood. This study interrogated how heterogeneity in liver cancer subtypes contributes to differences in invasive phenotypes and drug response. Utilizing histological analysis, quantitative 2D invasion metrics, reconstituted 3D hydrogels, and bioinformatics, our study linked cytoskeletal dynamics to differential invasion profiles and drug resistance in liver cancer subtypes. We investigated cytoskeletal regulation in 2D and 3D culture environments using two liver cancer cell lines, SNU-475 and HepG2, chosen for their distinct cytoskeletal features and invasion profiles. For SNU-475 cells, a model for aggressive liver cancer, many cytoskeletal inhibitors abrogated 2D migration but only some suppressed 3D migration. For HepG2 cells, cytoskeletal inhibition did not significantly affect 3D migration but did affect proliferative capabilities and spheroid core growth. This study highlights cytoskeleton driven phenotypic variation, their consequences and coexistence within the same tumor, as well as efficacy of targeting biophysical phenotypes that may be masked in traditional screens against tumor growth.

Treatment for liver cancer is complicated by its various subtypes, which show different responses to anticancer drugs. This study demonstrates the effectiveness of targeting biophysical phenotypes related to cytoskeleton properties that are usually masked in traditional drug screens.

Pharmacological Effects of Grifolin: Focusing on Anticancer Mechanisms

Grifolin is a volatile compound contained in essential oils of several medicinal plants. Several studies show that this substance has been the subject of numerous pharmacological investigations, which have yielded interesting results. Grifolin demonstrated beneficial effects for health via its multiple pharmacological activities. It has anti-microbial properties against bacteria, fungi, and parasites. In addition, grifolin exhibited remarkable anti-cancer effects on different human cancer cells. The anticancer action of this molecule is related to its ability to act at cellular and molecular levels on different checkpoints controlling the signaling pathways of human cancer cell lines. Grifolin can induce apoptosis, cell cycle arrest, autophagy, and senescence in these cells. Despite its major pharmacological properties, grifolin has only been investigated in vitro and in vivo. Therefore, further investigations concerning pharmacodynamic and pharmacokinetic tests are required for any possible pharmaceutical application of this substance. Moreover, toxicological tests and other investigations involving humans as a study model are required to validate the safety and clinical applications of grifolin.

ACTR3 promotes cell migration and invasion by inducing epithelial mesenchymal transition in pancreatic ductal adenocarcinoma

Background

Recurrence and metastasis are the major causes of pancreatic ductal adenocarcinoma (PDAC) mortality after treatment. The underlying molecular mechanism is poorly understood. Actin-related protein 3 (ACTR3) is an important component of the actin-related protein 2/3 complex, which is involved in the regulation of cell motility and epithelial mesenchymal transition (EMT) process. Previously published studies have indicated that ACTR3 expression is upregulated in several types of cancers, and promotes tumor development, including gastric cancer and hepatocellular carcinoma. However, to date, the expression levels and the role of ACTR3 in PDAC are not well understood.

Methods

In the present study, the expression levels of ACTR3 in PDAC tissue and the relationship of ACTR3 expression with clinical prognosis were analyzed by mRNA microarray and bioinformatics. The biological functions and underlying mechanism of ACTR3 in PDAC were examined by a series of assays, including Cell Counting Kit-8 (CCK-8), transwell assay, and Western blotting.

Results

We found that the expression of ACTR3 was significantly increased in PDAC tissues and cell lines. A higher expression of ACTR3 was predictive of poor outcome for patients with PDAC. In vitro, the knockdown of ACTR3 expression significantly inhibited the invasive and migratory capacity of PDAC cells, and altered the distribution of F-actin and the expression of EMT markers.

Conclusions

The findings of our study indicated that ACTR3 promotes cell migration and invasion by inducing EMT in PDAC, which may be a potential therapeutic target and prognostic indicator for PDAC patients.

Reviewing cancer's biology: an eclectic approach

BACKGROUND

Cancer refers to a group of some of the worldwide most diagnosed and deadliest pathophysiological conditions that conquered researchers' attention for decades and yet begs for more questions for a full comprehension of its complex cellular and molecular pathology.

MAIN BODY

The disease conditions are commonly characterized by unrestricted cell proliferation and dysfunctional replicative senescence pathways. In fact, the cell cycle operates under the rigorous control of complex signaling pathways involving cyclins and cyclin-dependent kinases assumed to be specific to each phase of the cycle. At each of these checkpoints, the cell is checked essentially for its DNA integrity. Genetic defects observed in these molecules (i.e., cyclins, cyclin-dependent kinases) are common features of cancer cells. Nevertheless, each cancer is different concerning its molecular and cellular etiology. These could range from the genetic defects mechanisms and/or the environmental conditions favoring epigenetically harbored homeostasis driving tumorigenesis alongside with the intratumoral heterogeneity with respect to the model that the tumor follows.

CONCLUSIONS

This review is not meant to be an exhaustive interpretation of carcinogenesis but to summarize some basic features of the molecular etiology of cancer and the intratumoral heterogeneity models that eventually bolster anticancer drug resistance for a more efficient design of drug targeting the pitfalls of the models.

Targeting cancer cell adhesion molecule, CD146, with low-dose gold nanorods and mild hyperthermia disrupts actin cytoskeleton and cancer cell migration

Cluster of differentiation 146 (CD146), a cancer cell adhesion molecule, is over-expressed on the surfaces of melanoma, breast, ovarian, and prostate cancer cells, and its high expression indicates the migration tendency of these cancer cells and poor patient prognosis. Here, we hypothesize that targeting the CD146 with low-dose gold nanorods combined with mild hyperthermia can stop the migration of these cancer cells. Two metastatic cancer cells including a melanoma and a breast cancer cell line are selected as the model systems. Cell migration assays show that the migration of both cell lines can be completely stopped by the treatment. Atomic force microscopy and super resolution fluorescence microscopy reveal the alterations of actin cytoskeleton and cell morphology correspond to the inhibited cell migration. Further mechanistic analysis indicates the treatment disrupts the actin cytoskeleton by a synergistic mechanism including depleting membrane CD146 and interfering ezrin-radixin-moesin phosphorylation. As a result, we believe targeting CD146 with low-dose gold nanorods and mild hyperthermia could be a versatile, effective, and safe approach for stopping cancer metastasis. More broadly, the concept of targeting cancer cell surface markers that connect the underlying actin cytoskeleton, offers enormous potential in treating cancer metastasis, which accounts for more than 90% of cancer-associated mortality.

Identification of lncRNA-associated competing endogenous RNA networks for occurrence and prognosis of gastric carcinoma

Background

Gastric cancer (GC) is one of the common digestive malignancies worldwide and causes a severe public health issue. So far, the underlying mechanisms of GC are largely unclear. Thus, we aim to identify the long non‐coding RNA (lncRNA)‐associated competing endogenous RNA (ceRNA) for GC.

Methods

TCGA database was downloaded and used for the identification of differentially expressed (DE) lncRNAs, miRNAs, and mRNAs, respectively. Then, the ceRNA network was constructed via multiple online datasets and approaches. In addition, various in vitro assays were carried out to validate the effect of certain hub lncRNAs.

Results

We constructed a ceRNA network, including 76 lncRNAs, 18 miRNAs, and 159 mRNAs, which involved multiple critical pathways. Next, univariate and multivariate analysis demonstrated 11 lncRNAs, including LINC02731, MIR99AHG, INHBA‐AS1, CCDC144NL‐AS1, VLDLR‐AS1, LIFR‐AS1, A2M‐AS1, LINC01537, and LINC00702, and were associated with OS, and nine of those lncRNAs were considered as hub lncRNAs involved in the sub‐ceRNA network. The in vitro assay indicated two lncRNAs, INHBA‐AS1 and CCDC144NL‐AS1, which were positively related to the GC aggressive features, including proliferation, invasion, and migration.

Conclusions

We identified nine hub lncRNAs and the associated ceRNA network related to the prognosis of GC, and then validated two out of them as promising oncogenes in GC.

Blocking MMP-12-modulated epithelial-mesenchymal transition by repurposing penfluridol restrains lung adenocarcinoma metastasis via uPA/uPAR/TGF-β/Akt pathway

PURPOSE

Metastasis of lung adenocarcinoma (LADC) is a crucial factor determining patient survival. Repurposing of the antipsychotic agent penfluridol has been found to be effective in the inhibition of growth of various cancers. As yet, however, the anti-metastatic effect of penfluridol on LADC has rarely been investigated. Herein, we addressed the therapeutic potential of penfluridol on the invasion/metastasis of LADC cells harboring different epidermal growth factor receptor (EGFR) mutation statuses.

METHODS

MTS viability, transwell migration and invasion, and tumor endothelium adhesion assays were employed to determine cytotoxic and anti-metastatic effects of penfluridol on LADC cells. Protease array, Western blot, immunohistochemistry (IHC), immunofluorescence (IF) staining, and expression knockdown by shRNA or exogenous overexpression by DNA plasmid transfection were performed to explore the underlying mechanisms, both in vitro and in vivo.

RESULTS

We found that nontoxic concentrations of penfluridol reduced the migration, invasion and adhesion of LADC cells. Protease array screening identified matrix metalloproteinase-12 (MMP-12) as a potential target of penfluridol to modulate the motility and adhesion of LADC cells. In addition, we found that MMP-12 exhibited the most significantly adverse prognostic effect in LADC among 39 cancer types. Mechanistic investigations revealed that penfluridol inhibited the urokinase plasminogen activator (uPA)/uPA receptor/transforming growth factor-β/Akt axis to downregulate MMP-12 expression and, subsequently, reverse MMP-12-induced epithelial-mesenchymal transition (EMT). Subsequent analysis of clinical LADC samples revealed a positive correlation between MMP12 and mesenchymal-related gene expression levels. A lower survival rate was found in LADC patients with a SNAl1high/MMP12high profile compared to those with a SNAl1low/MMP12low profile.

CONCLUSIONS

Our results indicate that MMP-12 may serve as a useful biomarker for predicting LADC progression and as a promising penfluridol target for treating metastatic LADC.

Concomitant and decoupled effects of cigarette smoke and SCAL1 upregulation on oncogenic phenotypes and ROS detoxification in lung adenocarcinoma cells

Lung cancer is the leading cause of cancer deaths worldwide, with smoking as its primary predisposing factor. Although carcinogens in cigarettes are known to cause oncogenic DNA alterations, analyses of patient cohorts revealed heterogeneous genetic aberrations with no clear driver mutations. The contribution of noncoding RNAs (ncRNAs) in the pathogenesis of lung cancer has since been demonstrated. Their dysregulation has been linked to cancer initiation and progression. A novel long noncoding RNA (lncRNA) called smoke and cancer-associated lncRNA 1 (SCAL1) was recently found upregulated in smoke-exposed adenocarcinomic alveolar epithelial cells. The present study characterized the phenotypic consequences of SCAL1 overexpression and knockdown using A549 cells as model system, with or without prior exposure to cigarette smoke extract (CSE). Increase in SCAL1 levels either by CSE treatment or SCAL1 overexpression led to increased cell migration, extensive cytoskeletal remodeling, and resistance to apoptosis. Further, SCAL1 levels were negatively correlated with intracellular levels of reactive oxygen species (ROS). In contrast, SCAL1 knockdown showed converse results for these assays. These results confirm the oncogenic function of SCAL1 and its role as a CSE-activated lncRNA that mediates ROS detoxification in A549 cells, thereby allowing them to develop resistance to and survive smoke-induced toxicity.

SLPI facilitates cell migration by regulating lamellipodia/ruffles and desmosomes, in which Galectin4 plays an important role

To elucidate the underlying mechanism of secretory leukocyte protease inhibitor (SLPI)-induced cell migration, we compared SLPI-deleted human gingival carcinoma Ca9-22 (ΔSLPI) cells and original (wild-type: wt) Ca9-22 cells using several microscopic imaging methods and gene expression analysis. Our results indicated reduced migration of ΔSLPI cells compared to wtCa9-22 cells. The lamellipodia/dorsal ruffles were smaller and moved slower in ΔSLPI cells compared to wtCa9-22 cells. Furthermore, well-developed intermediate filament bundles were observed at the desmosome junction of ΔSLPI cells. In addition, Galectin4 was strongly expressed in ΔSLPI cells, and its forced expression suppressed migration of wtCa9-22 cells. Taken together, SLPI facilitates cell migration by regulating lamellipodia/ruffles and desmosomes, in which Galectin4 plays an important role.

Bioinformatics-based analysis of the association between the A1-chimaerin (CHN1) gene and gastric cancer

Gastric cancer (GC) is one of the most common causes of cancer-related deaths worldwide and the identification of additional therapeutic targets and biomarkers has become vital. The A1-chimaerin (CHN1) gene encodes a ras-related protein that can be activated or inactivated by binding to GTP or GDP. The present study aimed to assess the expression of CHN1 in GC tissue and cells, to explore its relationship with GC progression, and to discover the potential mechanisms underlying these associations. The ONCOMINE database and The Cancer Genome Atlas (TCGA) were used to determine the transcriptional levels of CHN1 in GC. Western blot and immunohistochemistry were used for detecting protein expression. Correlations between CHN1 levels and the clinical outcomes of GC patients were examined using Kaplan–Meier and Cox regression analyses. Moreover, the CIBERSORT algorithm was used to estimate immune cell infiltration. In GC patients, CHN1 transcription and CHN1 protein expression were upregulated, and a high expression of CHN1 was remarkably linked to poor survival in GC patients. CHN1 expression was associated with immune infiltrates and this gene showed potential involvement in multiple cancer-related pathways. Furthermore, the expression of CHN1 was correlated with the immunotherapeutic response. Finally, our results indicated that the pro-carcinogenic role of CHN1 may involve DNA methylation. To our knowledge, this is the first report characterizing CHN1 expression in GC. Our results show that high CHN1 levels could be used as a clinical biomarker for poor prognosis and that CHN1 inhibitors may have potential as anti-cancer drugs.

NudC L279P Mutation Destabilizes Filamin A by Inhibiting the Hsp90 Chaperoning Pathway and Suppresses Cell Migration

Filamin A, the first discovered non-muscle actin filament cross-linking protein, plays a crucial role in regulating cell migration that participates in diverse cellular and developmental processes. However, the regulatory mechanism of filamin A stability remains unclear. Here, we find that nuclear distribution gene C (NudC), a cochaperone of heat shock protein 90 (Hsp90), is required to stabilize filamin A in mammalian cells. Immunoprecipitation-mass spectrometry and western blotting analyses reveal that NudC interacts with filamin A. Overexpression of human NudC-L279P (an evolutionarily conserved mutation in NudC that impairs its chaperone activity) not only decreases the protein level of filamin A but also results in actin disorganization and the suppression of cell migration. Ectopic expression of filamin A is able to reverse these defects induced by the overexpression of NudC-L279P. Furthermore, Hsp90 forms a complex with filamin A. The inhibition of Hsp90 ATPase activity by either geldanamycin or radicicol decreases the protein stability of filamin A. In addition, ectopic expression of Hsp90 efficiently restores NudC-L279P overexpression-induced protein stability and functional defects of filamin A. Taken together, these data suggest NudC L279P mutation destabilizes filamin A by inhibiting the Hsp90 chaperoning pathway and suppresses cell migration.

Ratchetaxis in Channels: Entry Point and Local Asymmetry Set Cell Directions in Confinement

Cell motility is essential in a variety of biological phenomena ranging from early development to organ homeostasis and diseases. This phenomenon has mainly been studied and characterized on flat surfaces in vitro, whereas such conditions are rarely observed in vivo. Recently, cell motion in three-dimensional microfabricated channels was reported to be possible, and it was shown that confined cells push on walls. However, rules setting cell directions in this context have not yet been characterized. Here, we show by using assays that ratchetaxis operates in three-dimensional ratchets in fibroblasts and epithelial cancerous cells. Open ratchets rectify cell motion, whereas closed ratchets impose direct cell migration along channels set by the cell orientation at the channel entry point. We also show that nuclei are pressed in constriction zones through mechanisms involving dynamic asymmetries of focal contacts, stress fibers, and intermediate filaments. Interestingly, cells do not pass these constricting zones when they contain a defective keratin fusion protein implicated in squamous cancer. By combining ratchetaxis with chemical gradients, we finally report that cells are sensitive to local asymmetries in confinement and that topological and chemical cues may be encoded differently by cells. Overall, our ratchet channels could mimic small blood vessels in which cells such as circulating tumor cells are confined; cells can probe local asymmetries that determine their entry into tissues and their subsequent direction. Our results shed light on invasion mechanisms in cancer.

NDRG1 regulates Filopodia-induced Colorectal Cancer invasiveness via modulating CDC42 activity

N-myc downstream regulated gene-1 (NDRG1) has been identified as a putative metastasis suppressor gene and proved to be a key player in cancer spreading and proliferation in our previous work. However, the effects of NDRG1 on tumor invasion and the mechanisms behind it are rarely understood. Here we provided in silico evidence that NDRG1 plays a crucial role in actin reorganization in colorectal cancer (CRC). Through in vitro experiments, we next observed filopodia formation was altered in NDRG1-modified cell lines, while cell division cycle-42 (CDC42) displayed excessive activation in NDRG1-silenced cells. Mechanistically, NDRG1 loss disrupts the binding between RhoGDIα and CDC42 and triggers the activation of CDC42 and the downstream cascades PAK1/Cofilin, thereby promotes the formation of filopodia and invasiveness of CRC. The knockdown of NDRG1 led to enhanced dissemination of CRC cells in vivo and correlates with active CDC42 expression. Using clinical sample analysis, we found an elevated level of active CDC42 in patients with advanced T stage, and it was negatively related to NDRG1 expression. In sum, these results uncover a mechanism utilized by NDRG1 to regulate CDC42 activity in coordinating cytoskeleton reorganization, which was crucial in cancer invasion.

Inhibitory effects of terrein on lung cancer cell metastasis and angiogenesis

Cancer metastasis is the leading cause of mortality in cancer patients. Over 70% of lung cancer patients are diagnosed at advanced or metastatic stages, and this results in an increased incidence of mortality. Terrein is a secondary bioactive fungal metabolite isolated from Aspergillus terreus. Numerous studies have demonstrated that terrein has anticancer properties, but in the present study, the cellular mechanisms underlying the inhibition of lung cancer cell metastasis by terrein was investigated for the first time. Using MTT assays, the cytotoxic effects of terrein were first examined in human lung cancer cells (A549 cells) and then compared with its cytotoxic effects in three noncancer control cell lines (Vero kidney, L6 skeletal muscle and H9C2 cardiomyoblast cells). The results indicated that terrein significantly reduced the viability of all these cells but exhibited a different level of toxicity in each cell type; these results revealed a specific concentration range in which the effect of terrein was specific to A549 cells. This significant cytotoxic effect of terrein in A549 cells was verified using LDH assays. It was then demonstrated that terrein attenuated the proliferation of A549 cells using IncuCyte image analysis. Regarding its antimetastatic effects, terrein significantly inhibited A549 cell adhesion, migration and invasion. In addition, terrein suppressed the angiogenic processes of A549 cells, including vascular endothelial growth factor (VEGF) secretion, capillary-like tube formation and VEGF/VEGFR2 interaction. These phenomena were accompanied by reduced protein levels of integrins, FAK, and their downstream mediators (e.g., PI3K, AKT, mTORC1 and P70S6K). All these data indicated that terrein was able to inhibit all the major metastatic processes in human lung cancer cells, which is crucial for cancer treatment.

Mutation-specific non-canonical pathway of PTEN as a distinct therapeutic target for glioblastoma

PTEN is one of the most frequently altered tumor suppressor genes in malignant tumors. The dominant-negative effect of PTEN alteration suggests that the aberrant function of PTEN mutation might be more disastrous than deletion, the most frequent genomic event in glioblastoma (GBM). This study aimed to understand the functional properties of various PTEN missense mutations and to investigate their clinical relevance. The genomic landscape of PTEN alteration was analyzed using the Samsung Medical Center GBM cohort and validated via The Cancer Genome Atlas dataset. Several hotspot mutations were identified, and their subcellular distributions and phenotypes were evaluated. We established a library of cancer cell lines that overexpress these mutant proteins using the U87MG and patient-derived cell models lacking functional PTEN. PTEN mutations were categorized into two major subsets: missense mutations in the phosphatase domain and truncal mutations in the C2 domain. We determined the subcellular compartmentalization of four mutant proteins (H93Y, C124S, R130Q, and R173C) from the former group and found that they had distinct localizations; those associated with invasive phenotypes ('edge mutations') localized to the cell periphery, while the R173C mutant localized to the nucleus. Invasive phenotypes derived from edge substitutions were unaffected by an anti-PI3K/Akt agent but were disrupted by microtubule inhibitors. PTEN mutations exhibit distinct functional properties regarding their subcellular localization. Further, some missense mutations ('edge mutations') in the phosphatase domain caused enhanced invasiveness associated with dysfunctional cytoskeletal assembly, thus suggesting it to be a potent therapeutic target.

PEG-GO@XN nanocomposite suppresses breast cancer metastasis via inhibition of mitochondrial oxidative phosphorylation and blockade of epithelial-to-mesenchymal transition

Metastatic breast cancer is a significant contributor to mortality among women, but its complex regulation represents a barrier to precision targeting. In the present study, a graphene-based nanocomposite which probes and selectively inhibits cancer cell motility is described. By controllable coupling of prenylated chalcone xanthohumol, an efficient inhibitor of mitochondrial electron transport chain complex I, with PEGylated graphene oxide nanosheet, a PEG-GO@XN nanocomposite with good stability and biocompatibility is synthesized. PEG-GO@XN is capable of inhibiting mitochondrial oxidative phosphorylation selectively in MDA-MB-231 and MDA-MB-436 metastatic breast cancer cells. PEG-GO@XN reduces the production of ATP, impairs the formation of F-actin cytoskeleton in the lamellipodia, and blocks the migration and invasion of breast cancer cells in vitro, without interfering the proliferation and metabolism of non-cancerous cells. More importantly, PEG-GO@XN suppresses the metastasis of MDA-MB-231 cells to lung in nude mice. PEG-GO@XN abolishes the TGF-β1-induced down-regulation of E-cadherin and up-regulation of N-cadherin, vimentin, Snail and Twist, thus causes the maintenance of "epithelial-like" rather than the "mesenchymal-like" features, and decreases the motility potential of breast cancer cells. Taken together, this research unveils the enormous potential of PEG-GO@XN to suppress metastatic breast cancer by selective targeting oxidative phosphorylation and epithelial-mesenchymal transition of cancer cells and thereby providing insights on metastatic cancer treatment.

CD9, a tetraspanin target for cancer therapy?

In the present minireview, we intend to provide a brief history of the field of CD9 involvement in oncogenesis and in the metastatic process of cancer, considering its potential value as a tumor-associated antigenic target. Over the years, CD9 has been identified as a favorable prognostic marker or predictor of metastatic potential depending on the cancer type. To understand its implications in cancer beside its use as an antigenic biomarker, it is essential to know its physiological functions, including its molecular partners in a given cell system. Moreover, the discovery that CD9 is one of the most specific and broadly expressed markers of extracellular membrane vesicles, nanometer-sized entities that are released into extracellular space and various physiological body fluids and play a role in intercellular communication under physiological and pathological conditions, notably the establishment of cancer metastases, has added a new dimension to our knowledge of CD9 function in cancer. Here, we will discuss these issues as well as the possible cancer therapeutic implications of CD9, their limitations, and pitfalls.

The action of hyaluronan in functional properties, morphology and expression of matrix effectors in mammary cancer cells depends on its molecular size

Breast cancer constitutes a heterogeneous disease. The expression profiles of estrogen receptors (ERs), as well as the expression patterns of extracellular matrix (ECM) macromolecules, determine its development and progression. Hyaluronan (HA) is an ECM molecule that regulates breast cancer cells' properties in a molecular size-dependent way. Previous studies have shown that 200-kDa HA fragments modulate the functional properties, morphology, and expression of several matrix mediators of the highly metastatic ERα^- /ERβ⁺ MDA-MB-231 cells. In order to evaluate the effects of HA fragments (< 10, 30 and 200-kDa) in ERβ-suppressed breast cancer cells, the shERβ MDA-MB-231 cells were used. These cells are less aggressive when compared with MDA-MB-231 cells. To this end, the functional properties, the morphology, and the expression of the molecules associated with breast cancer cells metastatic potential were studied. Notably, both cell proliferation and invasion were significantly reduced after treatment with 200-kDa HA. Moreover, as assessed by scanning electron microscopy, 200-kDa HA affected cellular morphology, and as assessed by qPCR, upregulated the epithelial marker Ε-cadherin. The expression profiles of ECM mediators, such as HAS2, CD44, and MMP7, were also altered. On the other hand, cellular migration and the expression levels of syndecan-4 (SDC-4) were not significantly affected in contrast to our observations regarding MDA-MB-231 cells. These novel data demonstrate that the molecular size of the HA determines its effects on ERβ-suppressed breast cancer cells and that 200-kDa HA exhibits antiproliferative effects on these cells. A deeper understanding of this mechanism may contribute to the development of therapeutic strategies against breast cancer.