Cellular protrusions--lamellipodia, filopodia, invadopodia and podosomes--and their roles in progression of orofacial tumours: current understanding

Explorative 3-D culture of early secondary follicles in a time lapse system for up to 36 days gives valuable, but limited insights in follicular development

BACKGROUND

Cryopreservation of ovarian cortical tissue is an important option for female fertility preservation. This is particularly valuable for cancer patients who need to be treated urgently with chemotherapy, leaving no time for hormonal stimulation. The transfer of malignant cells in certain cancers remains as a potential risk after freezing, thawing and transplantation of ovarian tissue while isolation and in vitro growth (IVG) of follicles could be a safe alternate approach of female fertility protection.

METHODS

Ovarian cortex tissue was frozen, thawed and cultured for 8 days prior to isolating and embedding of early secondary follicles in a 3D matrix, suitable for time lapse monitoring for up to 36 days. Continuous growth of a theca-like cell layer and extrafollicular protrusions were visually evaluated with a permanent monitoring system facilitating real-time follicular development without deviations in the culture conditions. Occurrence of theca cell growth was visually characterized by extrafollicular formation of cells, beyond the outer follicle boundaries. To validate the results observed by time-lapse monitoring, live cell imaging was conducted and determined with immunofluorescence staining.

RESULTS

Individual follicles significantly increased in size over time. Time-lapse video monitoring revealed extending and retracting of filopodia-like structures in the outer follicular region adjacent to the 3D environment. Theca-like cells and actin components of filopodia-like structures were identified based on immunofluorescence staining.

CONCLUSIONS

Time lapse monitoring of 3-D cultured follicles is a promising explorative approach to obtain valuable visual insights regarding the many facets of follicular growth and to optimize follicular culture conditions towards a clinical application. As the study is limited by a lack of mechanistic insights into theca cell differentiation and filopodia function, additional studies are necessary to validate the preliminary results of this approach.

The PTTG1/VASP axis promotes oral squamous cell carcinoma metastasis by modulating focal adhesion and actin filaments

The dynamics of focal adhesions (FAs) are essential physiological processes involved in cell spreading, metastasis, and regulation of the actin cytoskeleton. FAs are complex structures comprising proteins, such as paxillin and zyxin, which interact with extracellular membranes and influence cell motility and morphology. Although related studies have been reported in various cancers, the function and molecular mechanisms of oral squamous cell carcinoma (OSCC) remain unknown. We investigated the coordination between the actin cytoskeleton and FA proteins, specifically introducing pituitary tumor-transforming gene 1 (PTTG1; also known as PTTG1 regulator of sister chromatid separation, securin) into OSCC. Furthermore, we explored the co-localization of several FAs and PTTG1 through small interfering RNA (siRNA) control or siRNA-vasodilator-stimulated phosphoprotein (VASP) and -PTTG1, examining the mechanisms mediated by the induced changes in OSCC both in vitro and in vivo. The knockdown of VASP and PTTG1 regulates the dynamic actin cytoskeleton, restricting cell protrusion and motility from the front to the rear of OSCC cells. Our findings may provide new insights into how cells interact with each other on the surface of FAs in OSCC, influencing metastatic properties.

Disrupting Cdc42 activation-driven filopodia formation with low-intensity ultrasound and microbubbles: A novel strategy to block ovarian cancer metastasis

Metastasis is a primary cause of mortality and treatment failure in ovarian cancer, with limited effective therapeutic strategies. Low-intensity ultrasound (LIUS) and microbubbles (MBs) has been demonstrated as an adjunctive technique capable of enhancing drug delivery and suppressing tumor metastasis. However, the underlying mechanisms remain incompletely understood. In this study, we aimed to investigate whether LIUS + MBs alone could suppress tumor metastasis and to explore its mechanism of action through disruption of the cytoskeletal remodeling in filopodia, an essential structure in the early stages of cancer cell dissemination. Based on cell-based experiments to determine the optimal parameters, our results showed LIUS + MBs significantly inhibited the migration and invasion of ovarian cancer cells. In vivo, LIUS + MBs treatment markedly suppressed the overall metastasis in the orthotopic ovarian cancer model, and in both the intraperitoneal and hematogenous metastatic models established by injecting pretreated cells. Morphologically, such treatment led to a notable reduction in the length and number of filopodia, while the number of lamellipodia remained unaffected. At the molecular level, LIUS + MBs disturbed filopodia formation and the metastatic potential of ovarian cancer cells by suppressing the activation of Cdc42, a key regulator of cytoskeletal dynamics. The inhibitory effect was reversed by the overexpression of Cdc42CA. Further proteomic and bioinformatics analysis implied that LIUS + MBs may reduce Cdc42 activity by upregulating the expression of GTPase-activating proteins (GAPs). Our research provides novel insight into the mechanism by which LIUS + MBs can inhibit tumor metastasis, highlighting its role in disturbing the Cdc42-mediated cytoskeletal remodelling of filopodia.

Are hypoxia-related proteins associated with the invasiveness of glandular odontogenic cysts? A multicenter study

OBJECTIVE

The study aimed to investigate the expression of hypoxia markers associated with invadopodia in glandular odontogenic cysts and to explore an association between this expression with the aggressive biological behaviour of this odontogenic cyst.

DESIGN

Immunohistochemistry was employed to assess the expression of hypoxia-inducible factor 1 alpha (HIF-1α), notch homologous protein of the neurogenic locus 1 (NOTCH-1), disintegrin and metalloproteinase-12 (ADAM-12), and heparin-binding epidermal growth factor (HB-EGF) in 17 samples of glandular odontogenic cysts, 10 samples of calcifying odontogenic cysts, and 10 samples of dental follicles.

RESULTS

The glandular odontogenic cyst samples exhibited increased expression of HIF-1α, NOTCH-1, ADAM-12 and HBEGF proteins compared with calcifying odontogenic cyst and dental follicle samples. HIF-1α demonstrated localization primarily within the nuclei of cystic epithelial cells of the glandular odontogenic cyst. NOTCH-1 and ADAM-12 exhibited expression in the cytoplasm and nuclei of epithelial and mucous cells of the glandular odontogenic cyst, of whereas HB-EGF was predominantly expressed in the cytoplasm. Weak labeling of these proteins was observed in the odontogenic epithelium of the calcifying odontogenic cyst and dental follicle samples.

CONCLUSIONS

The hypoxia-related signaling proteins are overexpressed in glandular odontogenic cyst when compared with calcifying odontogenic cyst and dental follicle. The reported aggressiveness of glandular odontogenic cyst can be partially explained by the expression of these proteins.

Cell blebbing novel therapeutic possibilities to counter metastasis

Cells constantly reshape there plasma membrane and cytoskeleton during physiological and pathological processes (Hagmann et al. in J Cell Biochem 73:488-499, 1999). Cell blebbing, the formation of bulges or protrusions on the cell membrane, is related to mechanical stress, changes in intracellular pressure, chemical signals, or genetic anomalies. These membrane bulges interfere with the force balance of actin filaments, microtubules, and intermediate filaments, the basic components of the cytoskeleton (Charras in J Microsc 231:466-478, 2008). In the past, these blebs with circular structures were considered apoptotic markers (Blaser et al. in Dev Cell 11:613-627, 2006). Cell blebbing activates phagocytes and promotes the rapid removal of intrinsic compartments. However, recent studies have revealed that blebbing is associated with dynamic cell reorganization and alters the movement of cells in-vivo and in-vitro (Charras and Paluch in Nat Rev Mol Cell Biol 9:730-736, 2008). During tumor progression, blebbing promotes invasion of cancer cells into blood, and lymphatic vessels, facilitating tumor progression and metastasis (Weems et al. in Nature 615:517-525, 2023). Blebbing is a dominant feature of tumor cells generally absent in normal cells. Restricting tumor blebbing reduces anoikis resistance (survival in suspension) (Weems et al. in Nature 615:517-525, 2023). Hence, therapeutic intervention with targeting blebbing could be highly selective for proliferating pro-metastatic tumor cells, providing a novel therapeutic pathway for tumor metastasis with minimal side effects. Here, we review the association between cell blebbing and tumor cells, to uncover new research directions and strategies for metastatic cancer therapy. Finaly, we aim to identify the druggable targets of metastatic cancer in relation to cell blebbing.

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.

Emerging roles of deubiquitinating enzymes in actin cytoskeleton and tumor metastasis

BACKGROUND

Metastasis accounts for the majority of cancer-related deaths. Actin dynamics and actin-based cell migration and invasion are important factors in cancer metastasis. Metastasis is characterized by actin polymerization and depolymerization, which are precisely regulated by molecular changes involving a plethora of actin regulators, including actin-binding proteins (ABPs) and signalling pathways, that enable cancer cell dissemination from the primary tumour. Research on deubiquitinating enzymes (DUBs) has revealed their vital roles in actin dynamics and actin-based migration and invasion during cancer metastasis.

CONCLUSION

Here, we review how DUBs drive tumour metastasis by participating in actin rearrangement and actin-based migration and invasion. We summarize the well-characterized and essential actin cytoskeleton signalling molecules related to DUBs, including Rho GTPases, Src kinases, and ABPs such as cofilin and cortactin. Other DUBs that modulate actin-based migration signalling pathways are also discussed. Finally, we discuss and address therapeutic opportunities and ongoing challenges related to DUBs with respect to actin dynamics.

Probing the protrusions: lamellipodia and filopodia in cancer invasion and beyond

The dynamic protrusions of lamellipodia and filopodia have emerged as crucial players in tumor progression and metastasis. These membrane structures, governed by intricate actin cytoskeletal rearrangements, facilitate cancer cell migration, invasion, and interaction with the tumor microenvironment. This review provides a comprehensive examination of the structural and functional attributes of lamellipodia and filopodia, shedding light on their pivotal roles in mediating cancer invasion. Navigating through the intricate landscape of cancer biology, the review illuminates the intricate signaling pathways and regulatory mechanisms orchestrating the formation and activity of these protrusions. The discussion extends to the clinical implications of lamellipodia and filopodia, exploring their potential as diagnostic and prognostic markers, and delving into therapeutic strategies that target these structures to impede cancer progression. As we delve into the future, the review outlines emerging technologies and unexplored facets that beckon further research, emphasizing the need for collaborative efforts to unravel the complexities of lamellipodia and filopodia in cancer, ultimately paving the way for innovative therapeutic interventions.

Tanshinone IIA modulates cancer cell morphology and movement via Rho GTPases-mediated actin cytoskeleton remodeling

Actin filaments form unique structures with robust actin bundles and cytoskeletal networks affixed to the extracellular matrix and interact with neighboring cells, which are crucial structures for cancer cells to acquire a motile phenotype. This study aims to investigate a novel antitumor mechanism by which Tanshinone IIA (Tan IIA) modulates the morphology and migration of liver cancer cells via actin cytoskeleton regulation. 97H and Huh7 exhibited numerous tentacle-like protrusions that interacted with neighboring cells. Following treatment with Tan IIA, 97H and Huh7 showed a complete absence of cytoplasmic protrusion and adherens junctions, thereby effectively impeding their migration capability. The fluorescence staining of F-actin and microtubules indicated that these tentacle-like protrusions and cell-cell networks were actin-based structures that led to morphological changes after Tan IIA treatment by retracting and reorganizing beneath the membrane. Tan IIA can reverse the actin depolymerization and cell morphology alterations induced by latrunculin A. Tan IIA down-regulated actin and Rho GTPases expression significantly, as opposed to inducing Rho signaling activation. Preventing the activity of proteasomes and lysosomes had no discernible impact on the modifications in cellular structure and protein expression induced by Tan IIA. However, as demonstrated by the puromycin labeling technique, the newly synthesized proteins were significantly inhibited by Tan IIA. In conclusion, Tan IIA can induce dramatic actin cytoskeleton remodeling by inhibiting the protein synthesis of actin and Rho GTPases, resulting in the suppression of tumor growth and migration. Targeting the actin cytoskeleton of Tan IIA is a promising strategy for HCC treatment.

Tubulin Complexity in Cancer and Metastasis

Tubulin plays a fundamental role in cellular function and as the subject for microtubule-active agents in the treatment of ovarian cancer. Microtubule-binding proteins (e.g., tau, MAP1/2/4, EB1, CLIP, TOG, survivin, stathmin) and posttranslational modifications (e.g., tyrosination, deglutamylation, acetylation, glycation, phosphorylation, polyamination) further diversify tubulin functionality and may permit additional opportunities to understand microtubule behavior in disease and to develop microtubule-modifying approaches to combat ovarian cancer. Tubulin-based structures that project from suspended ovarian cancer cells known as microtentacles may contribute to metastatic potential of ovarian cancer cells and could represent an exciting novel therapeutic target.

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.

Response of mesenchymal stem cells to surface topography of scaffolds and the underlying mechanisms

Mesenchymal stem/stromal cells (MSCs) serve as essential components of regenerative medicine. Their destiny is influenced by the interaction of the cells with the external environment. In addition to the biochemical cues in a microenvironment, physical cues of the topography of the surrounding materials such as the extracellular matrix emerge as a crucial regulator of stem cell destiny and function. With recent advances in technologies of materials production and surface modification, surfaces with micro/nanotopographical characteristics can be fabricated to mimic the micro/nanoscale mechanical stimuli of the extracellular matrix environment and regulate the biological behavior of cells. Understanding the interaction of cells with the topography of a surface is conducive to the control of stem cell fate for application in regenerative medicine. However, the mechanisms by which topography affects the biological behavior of stem cells have not been fully elucidated. This review will present the effects of surface topography at the nano/micrometer scale on stem cell adhesion, morphology, proliferation, migration, and differentiation. It also focuses on discussing current theories about the sensing and recognition of surface topology cues, the transduction of the extracellular cues into plasma, and the final activation of related signaling pathways and downstream gene expression in MSCs. These insights will provide a theoretical basis for the future design of biomaterial scaffolds for application in regenerative medicine and tissue engineering.

Structure-Guided Prediction of the Functional Impact of DCLK1 Mutations on Tumorigenesis

Doublecortin-like kinase 1 (DCLK1) is a functional serine/threonine (S/T)-kinase and a member of the doublecortin family of proteins which are characterized by their ability to bind to microtubules (MTs). DCLK1 is a proposed cancer driver gene, and its upregulation is associated with poor overall survival in several solid cancer types. However, how DCLK1 associates with MTs and how its kinase function contributes to pro-tumorigenic processes is poorly understood. This review builds on structural models to propose not only the specific functions of the domains but also attempts to predict the impact of individual somatic missense mutations on DCLK1 functions. Somatic missense mutations in DCLK1 are most frequently located within the N-terminal MT binding region and likely impact on the ability of DCLK1 to bind to αβ-tubulin and to polymerize and stabilize MTs. Moreover, the MT binding affinity of DCLK1 is negatively regulated by its auto-phosphorylation, and therefore mutations that affect kinase activity are predicted to indirectly alter MT dynamics. The emerging picture portrays DCLK1 as an MT-associated protein whose interactions with tubulin heterodimers and MTs are tightly controlled processes which, when disrupted, may confer pro-tumorigenic properties.

Nanostructure Mediated Piezoelectric Effect of Tetragonal BaTiO3 Coatings on Bone Mesenchymal Stem Cell Shape and Osteogenic Differentiation

In recent years, porous titanium (Ti) scaffolds with BaTiO3 coatings have been designed to promote bone regeneration. However, the phase transitions of BaTiO3 have been understudied, and their coatings have yielded low effective piezoelectric coefficients (EPCs < 1 pm/V). In addition, piezoelectric nanomaterials bring many advantages in eliciting cell-specific responses. However, no study has attempted to design a nanostructured BaTiO3 coating with high EPCs. Herein, nanoparticulate tetragonal phase BaTiO3 coatings with cube-like nanoparticles but different effective piezoelectric coefficients were fabricated via anodization combining two hydrothermal processes. The effects of nanostructure-mediated piezoelectricity on the spreading, proliferation, and osteogenic differentiation of human jaw bone marrow mesenchymal stem cells (hJBMSCs) were explored. We found that the nanostructured tetragonal BaTiO3 coatings exhibited good biocompatibility and an EPC-dependent inhibitory effect on hJBMSC proliferation. The nanostructured tetragonal BaTiO3 coatings of relatively smaller EPCs (<10 pm/V) exhibited hJBMSC elongation and reorientation, broad lamellipodia extension, strong intercellular connection and osteogenic differentiation enhancement. Overall, the improved hJBMSC characteristics make the nanostructured tetragonal BaTiO3 coatings promising for application on implant surfaces to promote osseointegration.

ERRα Up-Regulates Invadopodia Formation by Targeting HMGCS1 to Promote Endometrial Cancer Invasion and Metastasis

Estrogen-related receptor alpha (ERRα) plays an important role in endometrial cancer (EC) progression. However, the biological roles of ERRα in EC invasion and metastasis are not clear. This study aimed to investigate the role of ERRα and 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) in regulating intracellular cholesterol metabolism to promote EC progression. ERRα and HMGCS1 interactions were detected by co-immunoprecipitation, and the effects of ERRα/HMGCS1 on the metastasis of EC were investigated by wound-healing and transwell chamber invasion assays. Cellular cholesterol content was measured to verify the relationship between ERRα and cellular cholesterol metabolism. Additionally, immunohistochemistry was performed to confirm that ERRα and HMGCS1 were related to EC progression. Furthermore, the mechanism was investigated using loss-of-function and gain-of-function assays or treatment with simvastatin. High expression levels of ERRα and HMGCS1 promoted intracellular cholesterol metabolism for invadopodia formation. Moreover, inhibiting ERRα and HMGCS1 expression significantly weakened the malignant progression of EC in vitro and in vivo. Our functional analysis showed that ERRα promoted EC invasion and metastasis through the HMGCS1-mediated intracellular cholesterol metabolism pathway, which was dependent on the epithelial-mesenchymal transition pathway. Our findings suggest that ERRα and HMGCS1 are potential targets to suppress EC progression.

Novel long noncoding RNA LINC02820 augments TNF signaling pathway to remodel cytoskeleton and potentiate metastasis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors in China. However, there are no targets to treat ESCC because the molecular mechanism behind the cancer is still unclear. Here, we found a novel long noncoding RNA LINC02820 was upregulated in ESCC and associated with the ESCC clinicopathological stage. Through a series of functional experiments, we observed that LINC02820 only promoted the migration and invasion capabilities of ESCC cell lines. Mechanically, we found that LINC02820 may affect the cytoskeletal remodeling, interact with splice factor 3B subunit 3 (SF3B3), and cooperate with TNFα to amplify the NF-κB signaling pathway, which can lead to ESCC metastasis. Overall, our findings revealed that LINC02820 is a potential biomarker and therapeutic target for the diagnosis and treatment of ESCC.

Ion Channels in Gliomas-From Molecular Basis to Treatment

Ion channels provide the basis for the nervous system's intrinsic electrical activity. Neuronal excitability is a characteristic property of neurons and is critical for all functions of the nervous system. Glia cells fulfill essential supportive roles, but unlike neurons, they also retain the ability to divide. This can lead to uncontrolled growth and the formation of gliomas. Ion channels are involved in the unique biology of gliomas pertaining to peritumoral pathology and seizures, diffuse invasion, and treatment resistance. The emerging picture shows ion channels in the brain at the crossroads of neurophysiology and fundamental pathophysiological processes of specific cancer behaviors as reflected by uncontrolled proliferation, infiltration, resistance to apoptosis, metabolism, and angiogenesis. Ion channels are highly druggable, making them an enticing therapeutic target. Targeting ion channels in difficult-to-treat brain tumors such as gliomas requires an understanding of their extremely heterogenous tumor microenvironment and highly diverse molecular profiles, both representing major causes of recurrence and treatment resistance. In this review, we survey the current knowledge on ion channels with oncogenic behavior within the heterogeneous group of gliomas, review ion channel gene expression as genomic biomarkers for glioma prognosis and provide an update on therapeutic perspectives for repurposed and novel ion channel inhibitors and electrotherapy.

Short- and long-term polystyrene nano- and microplastic exposure promotes oxidative stress and divergently affects skin cell architecture and Wnt/beta-catenin signaling

Nano- and microplastic particles (NMP) are strong environmental contaminants affecting marine ecosystems and human health. The negligible use of biodegradable plastics and the lack of knowledge about plastic uptake, accumulation, and functional consequences led us to investigate the short- and long-term effects in freshly isolated skin cells from mice. Using fluorescent NMP of several sizes (200 nm to 6 µm), efficient cellular uptake was observed, causing, however, only minor acute toxicity as metabolic activity and apoptosis data suggested, albeit changes in intracellular reactive species and thiol levels were observed. The internalized NMP induced an altered expression of various targets of the nuclear factor-2-related transcription factor 2 pathway and were accompanied by changed antioxidant and oxidative stress signaling responses, as suggested by altered heme oxygenase 1 and glutathione peroxide 2 levels. A highly increased beta-catenin expression under acute but not chronic NMP exposure was concomitant with a strong translocation from membrane to the nucleus and subsequent transcription activation of Wnt signaling target genes after both single-dose and chronic long-term NMP exposure. Moreover, fibroblast-to-myofibroblast transdifferentiation accompanied by an increase of α smooth muscle actin and collagen expression was observed. Together with several NMP-induced changes in junctional and adherence protein expression, our study for the first time elucidates the acute and chronic effects of NMP of different sizes in primary skin cells' signaling and functional biology, contributing to a better understanding of nano- and microplastic to health risks in higher vertebrates.

Filopodial adhesive force in discrete nodes revealed by integrin molecular tension imaging

Filopodia are narrow cell extensions involved in various physiological processes. Integrins mediate filopodia adhesion and likely transmit adhesive force to regulate filopodia formation and functions, but the force is extremely weak to study and remains poorly understood. Using integrative tension sensor (ITS), we imaged filopodia adhesive force at the single molecular tension level and investigated the force dynamics and sources. Results show that filopodia integrin tension (FIT) is generated in discrete foci (force nodes) along single filopodia with a spacing of ∼1 μm. Inhibitions of actin polymerization or myosin II activity markedly reduced FIT signals in force nodes at filopodia tips and at filopodia bases, respectively, suggesting differential force sources of FIT in the distal force nodes and proximal ones in filopodia. Using two ITS constructs with different force thresholds for activation, we showed that the molecular force level of FIT is greater at filopodia bases than that at filopodia tips. We also tested the role of vinculin and myosin X in the FIT transmission. With vinculin knockout in cells, filopodia and associated force nodes were still formed normally, suggesting that vinculin is dispensable for the formation of filopodia and force nodes. However, vinculin is indeed required for the transmission of strong FIT (capable of rupturing DNA in a shear conformation), as the strong FIT vanished in filopodia with vinculin knockout. Co-imaging of FIT and myosin X shows no apparent co-localization, demonstrating that myosin X is not directly responsible for generating FIT, despite its prominent role in filopodium elongation.

Small Extracellular Vesicles from Hypoxic Triple-Negative Breast Cancer Cells Induce Oxygen-Dependent Cell Invasion

Hypoxia, a condition of low oxygenation frequently found in triple-negative breast tumors (TNBC), promotes extracellular vesicle (EV) secretion and favors cell invasion, a complex process in which cell morphology is altered, dynamic focal adhesion spots are created, and ECM is remodeled. Here, we investigated the invasive properties triggered by TNBC-derived hypoxic small EV (SEVh) in vitro in cells cultured under hypoxic (1% O₂) and normoxic (20% O₂) conditions, using phenotypical and proteomic approaches. SEVh characterization demonstrated increased protein abundance and diversity over normoxic SEV (SEVn), with enrichment in pro-invasive pathways. In normoxic cells, SEVh promotes invasive behavior through pro-migratory morphology, invadopodia development, ECM degradation, and matrix metalloprotease (MMP) secretion. The proteome profiling of 20% O₂-cultured cells exposed to SEVh determined enrichment in metabolic processes and cell cycles, modulating cell health to escape apoptotic pathways. In hypoxia, SEVh was responsible for proteolytic and catabolic pathway inducement, interfering with integrin availability and gelatinase expression. Overall, our results demonstrate the importance of hypoxic signaling via SEV in tumors for the early establishment of metastasis.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

Inactivation of Wnt-LRP5 signaling suppresses the proliferation and migration of ovarian cancer cells

Background

Ovarian cancer (OCa) is the most lethal gynecological malignant tumor, with few or no specific symptoms in its early stage. There are many signaling pathways involved in the process of OCa progression, among which the highly complex Wnt signaling pathway plays a unique role in the occurrence and development of OCa because of its functions of regulating gene expression, cell proliferation, migration, and invasion. Lipoprotein associated receptor protein 5/6 (LRP5/6) binds to activate this key pathway. Therefore, it is very important to study the mechanism of Wnt-LRP5 signaling pathway in the proliferation and migration of OCa.

Methods

In the present study, we have investigated the role of Wnt-LRP5 signaling pathway in OCa proliferation and migration for the first time using the dominant negative plasmid of LRP5 (DN-LRP5) and human OCa cells HO8910PM plus in a mouse model.

Results

Our data showed inactivation of LRP5 resulted in shift of epithelial-mesenchymal transition (EMT), rearrangement of the cytoskeleton, lowered activity of pro-proliferation and pro-migration cancer signaling pathways including Akt, p38 and NF-κB, eventually decreased proliferation and migration of OCa cells HO8910PM in vitro. Moreover, in vivo OCa-DN-LRP5 mouse model developed significantly smaller tumors as determined by inoculation of HO8910PM-DN-LRP5 cells into nude mice.

Conclusions

Collectively, our results demonstrate the dominant role of Wnt-LRP5 in OCa proliferation and migration and its potential as a valuable therapeutic target.

Glandular odontogenic cysts: a collaborative investigation of 22 cases and proteins related to invasiveness

BACKGROUND

A glandular odontogenic cyst has an intriguing, aggressive behaviour whose mechanisms have not yet been clarified.

OBJECTIVE

To conduct a collaborative cross-sectional study on the clinical, demographic, microscopic, and immunohistochemical characteristics of glandular odontogenic cysts, emphasizing the histopathological characteristics and expression of proteins related to invasiveness.

METHODS

Twenty-two cases of glandular odontogenic cyst from three oral and maxillofacial pathology services in Brazil were selected from 1988 to 2018. Clinical and demographic data were collected. Histopathological features were evaluated in detail. Sixteen cases of glandular odontogenic cyst were also submitted to immunohistochemistry to detect MT1-MMP, TKS4, TKS5, and cortactin, the key regulators of invadopodia formation.

RESULTS

GOCs were primarily seen in men over 40 years of age, in the posterior mandible and the anterior maxilla as a unilocular, radiolucent lesion. All cases presented hobnail cells, clear cells, and variable thickness of the lining epithelium, three of the ten key histopathological parameters to be evaluated in glandular odontogenic cysts. Immunohistochemistry revealed a greater expression of the studied proteins in the glandular odontogenic cysts than in the controls (p <0.0001).

CONCLUSION

Overexpression of proteins that regulate cell invasiveness was identified, and the present study's findings suggest that invadopodia activity is a possible mechanism used by glandular odontogenic cysts to promote local invasion, which could partly explain its intriguing biological behaviour.

Iminodibenzyl induced redirected COX-2 activity inhibits breast cancer progression

Knocking down delta-5-desaturase (D5D) by siRNA or shRNA is a promising strategy to achieve 8-hydroxyoctanoic acid (8-HOA) production for cancer inhibition. However, the RNAi-based strategy to stimulate 8-HOA is restricted due to endonucleases mediated physiological degradation and off-target effects. Thus, to get persistent 8-HOA in the cancer cell, we recognized a D5D inhibitor Iminodibenzyl. Here, we have postulated that Iminodibenzyl, by inhibiting D5D activity, could shift the di-homo-gamma-linolenic acid (DGLA) peroxidation from arachidonic acid to 8-HOA in high COX-2 microenvironment of 4T1 and MDA-MB-231 breast cancer cells. We observed that Iminodibenzyl stimulated 8-HOA caused HDAC activity reduction resulting in intrinsic apoptosis pathway activation. Additionally, reduced filopodia and lamellipodia, and epithelial-mesenchymal transition markers give rise to decreased cancer cell migration. In the orthotopic breast cancer model, the combination of Iminodibenzyl and DGLA reduced tumor size. From in vitro and in vivo studies, we concluded that Iminodibenzyl could reprogram COX-2 induced DGLA peroxidation to produce anti-cancer activity.

Non-Coding RNAs in Invadopodia: New Insights Into Cancer Metastasis

Invadopodia are actin-rich structures and their formation is implicated in cancer invasion and metastasis. Growing evidence has shown that noncoding RNAs (ncRNAs) play important roles in pathological conditions, including tumorigenesis and metastasis. Although this is still a new area of research, ncRNAs appear to be promising biomarkers and therapeutic targets for cancer metastasis. However, understanding the roles of ncRNAs in invadopodia is still in the early stages and far from clinical application. In this mini-review, we summarize the roles of ncRNAs in invadopodia functions and discuss them in a therapeutic context. The current challenges and gaps in this field are also raised, and we provide some open questions to facilitate new ideas in targeting invadopodia in anticancer therapy.

Rac1-GTPase regulates compression-induced actin protrusions (CAPs) of mesenchymal stem cells in 3D collagen micro-tissues

Cells can sense mechanical signals through cytoskeleton reorganization. We previously discovered the formation of omni-directional actin protrusions upon compression loading, namely compression-induced actin protrusions (CAPs), in human mesenchymal stem cells (MSCs) in 3D micro-tissues. Here, the regulatory roles of three RhoGTPases (CDC42, Rac1 and RhoA) in the formation of CAPs were investigated. Upon compression loading, extensive formation of CAPs was found, significantly associated with an upregulated mRNA expression of Rac1 only, but not CDC42, nor RhoA. Upon chemical inhibition of these RhoGTPase activity during compression, only Rac1 activity was significantly suppressed, associating with the reduced CAP formation. Silencing the upstream regulators of these RhoGTPase pathways including Rac1 by specific siRNA dramatically disrupted actin cytoskeleton, distorted cell morphology and aborted CAP formation. Silencing cortactin (CTTN), a downstream effector of the Rac1 pathway, induced a compensatory upregulation of Rac1, enabling the MSCs to respond to the compression loading stimulus in terms of CAP formation, although at a reduced number. The importance of Rac1 signalling in CAP formation and the corresponding upregulation of lamellipodial markers also suggest that these CAPs are lamellipodia in nature. This study delineates the mechanism of compression-induced cytoskeleton reorganization, contributing to rationalizing mechanical loading regimes for functional tissue engineering.

Store operated calcium channels in cancer progression

In recent decades cancer emerged as one of the leading causes of death in the developed countries, with some types of cancer contributing to the top 10 causes of death on the list of the World Health Organization. Carcinogenesis, a malignant transformation causing formation of tumors in normal tissues, is associated with changes in the cell cycle caused by suppression of signaling pathways leading to cell death and facilitation of those enhancing proliferation. Further progression of cancer, during which benign tumors acquire more aggressive phenotypes, is characterized by metastatic dissemination through the body driven by augmented motility and invasiveness of cancer cells. All these processes are associated with alterations in calcium homeostasis in cancer cells, which promote their proliferation, motility and invasion, and dissuade cell death or cell cycle arrest. Remodeling of store-operated calcium entry (SOCE), one of the major pathways regulating intracellular Ca²⁺ concentration ([Ca²⁺]_i), manifests a key event in many of these processes. This review systematizes current knowledge on the mechanisms recruiting SOCE-related proteins in carcinogenesis and cancer progression.

Roles of regulator of chromosome condensation 2 in cancer: Beyond its regulatory function in cell cycle

Regulator of chromosome condensation 2 (RCC2) is an essential protein in order for mitosis to proceed properly. It localizes in the centrosome of chromosomes where is involved in chromosome segregation and cytokinesis. Furthermore, RCC2 associates with integrin networks at the plasma membrane where participates in the control of cell movement. Because of its known role in cell cycle, RCC2 has been linked with cancer progression. Several reports show that RCC2 induces cancer hallmarks, but the mechanisms explaining how RCC2 exerts these roles are widely unknown. Here, we aim to summarize the main findings explaining the roles and mechanisms of RCC2 in cancer promotion. RCC2 is overexpressed in different cancers, including glioblastoma, lung, ovarian, and esophageal which is related to proliferation, migration, invasion promotion in vitro and tumor progression and metastasis in vivo. Besides, RCC2 overexpression induces epithelial-mesenchymal transition and causes poorer prognosis in cancer patients. RCC2 overexpression has also been linked with resistance development to chemotherapy and radiotherapy by inhibiting apoptosis and activating cancer-promoting transcription factors. Unfortunately, not RCC2 inhibitors are currently available for further pre-clinical and clinical assays. Therefore, these findings emphasize the potential use of RCC2 as a targetable biomarker in cancer and highlight the importance for designing RCC2 chemical inhibitors to evaluate its efficacy in animal studies and clinical trials.

Altered regulation of cell migration in IRF6-mutated orofacial cleft patients-derived primary cells reveals a novel role of Rho GTPases in cleft/lip palate development

Orofacial clefts are the most common congenital craniofacial birth defects. They occur from a failure in cell proliferation and fusion of neural crest cells of the lip buds and/or palatal shelves. In this study, we investigate the genetic basis and molecular mechanisms in primary cells derived from a cleft and lip palate patient presenting van der Woude syndrome (VWS). Since mutations in the integrin genes are widely correlated with VWS, Interferon Regulatory Factor 6 (IRF6) screening was conducted in a cohort of 200 participants presenting with orofacial anomalies. Primary fibroblastic cells derived from the upper right gingiva and palatal regions were isolated and two cellular populations from two participants were obtained: a control with no cleft phenotype and a patient with a cleft phenotype typical of van der Woude syndrome (VWS). IRF6 targeted sequencing revealed mutations in two distinct families. Our results showed no alteration in the viability of the CLP/VWS patient cells, suggesting the phenotype associate with the disease is not secondary to a defect in cell proliferation. We did however detect a significant decrease in the migratory ability of the CLP with Van der Woude syndrome (CLP/VWS) patient cells, which could account for the phenotype. When compared to normal cells, patient cells showed a lack of polarization, which would account for their lack of mobility. Patient cells showed protrusions all around the cells and a lack of defined leading edge. This was reflected with actin staining, WAVE2 and Arp2 around the cell, and correlated with an increase in Rac1 activation. Consistently with the increase in Rac1 activation, patient cells showed a loss in the maturation of focal adhesions needed for contractility, which also accounts for the lack in cell migration. Our findings give increased understanding of the molecular mechanisms of VWS and expands the knowledge of van der Woude syndrome (VWS) occurrence by providing a strong molecular evidence that CLP with Van der Woude syndrome (CLP/VWS) phenotype is caused by a defect in normal physiological processes of cells.

StarD13 differentially regulates migration and invasion in prostate cancer cells

Prostate cancer is the second most commonly diagnosed cancer in men and one of the main leading causes of cancer deaths among men worldwide. Rapid uncontrolled growth and the ability to metastasize to other sites are key hallmarks in cancer development and progression. The Rho family of GTPases and its activators the GTPase-activating proteins (GAPs) are required for regulating cancer cell proliferation and migration. StarD13 is a GAP for Rho GTPases, specifically for RhoA and Cdc42. We have previously shown that StarD13 acts as a tumor suppressor in astrocytoma as well as breast and colorectal cancer. In this study, we performed a functional comparative analysis of StarD13 targets/and or interacting molecules to understand the general role that StarD13 plays in cancers. Our data highlight the importance of StarD13 in modulating several hallmarks of cancer. Findings from database mining and immunohistochemistry revealed that StarD13 is underexpressed in prostate cancers, in addition knocking down Stard13 increased cancer cell proliferation, consistent with its role as a tumor suppressor. Stard13 depletion, however, led to an increase in cell adhesion, which inhibited 2D cell migration. Most interestingly, StarD13 depletion increases invasion and matrix degradation, at least in part, through its regulation of Cdc42. Altogether, the data presented suggest that StarD13 acts as a tumor suppressor inhibiting prostate cancer cell invasion.

Podosome formation in the murine palatal mucosae: Its proteolytic role in rete peg formation

BACKGROUND

Basement membrane remodeling is an indispensable factor for oral mucosal rete peg formation, but how the basement membrane is remodeled remains unclear. Our previous study indicated that keratinocyte growth factor induces the assembly of podosomes, which are dynamic organelles critical for matrix remodeling in human immortalized oral epithelial cells. This study explores podosome formation and its role in basement membrane remodeling during murine oral mucosal rete peg formation.

METHODS

Perinatal murine palatal tissue slices were obtained from embryonic day 17.5 (E 17.5) to postnatal day 10.5 (P 10.5) BALB/c mice. Rete peg formation was observed by hematoxylin and eosin (HE) staining. Proteolysis of the basement membrane was detected by immunofluorescence staining. The assembly of podosomes and their correlation with basement membrane proteolysis were investigated by laser scanning confocal microscopy.

RESULTS

The shape of basal layer keratinocytes at the sites of emerging rete pegs changed from typically polygonal to spindle-shaped. Basement membrane proteolysis, indicated by decreased type IV collagen (Col IV) staining, was detected during rete peg formation. Classical markers for podosomes, including cortactin/Tks5, WASP, and matrix metalloproteinase foci, were easily observed at the spindle-shaped cells. Podosomes were visible in regions where there was a significant decrease in Col IV staining.

CONCLUSIONS

These observations indicated that podosomes form at the front of the emerging rete peg and may play a pivotal role in basement membrane remodeling during rete peg formation.

Berbamine Suppresses the Progression of Bladder Cancer by Modulating the ROS/NF-κB Axis

Berbamine (BBM), one of the bioactive ingredients extracted from Berberis plants, has attracted intensive attention because of its significant antitumor activity against various malignancies. However, the exact role and potential molecular mechanism of berbamine in bladder cancer (BCa) remain unclear. In the present study, our results showed that berbamine inhibited cell viability, colony formation, and proliferation. Additionally, berbamine induced cell cycle arrest at S phase by a synergistic mechanism involving stimulation of P21 and P27 protein expression as well as downregulation of CyclinD, CyclinA2, and CDK2 protein expression. In addition to suppressing epithelial-mesenchymal transition (EMT), berbamine rearranged the cytoskeleton to inhibit cell metastasis. Mechanistically, the expression of P65, P-P65, and P-IκBα was decreased upon berbamine treatment, yet P65 overexpression abrogated the effects of berbamine on the proliferative and metastatic potential of BCa cells, which indicated that berbamine attenuated the malignant biological activities of BCa cells by inhibiting the NF-κB pathway. More importantly, berbamine increased the intracellular reactive oxygen species (ROS) level through the downregulation of antioxidative genes such as Nrf2, HO-1, SOD2, and GPX-1. Following ROS accumulation, the intrinsic apoptotic pathway was triggered by an increase in the ratio of Bax/Bcl-2. Furthermore, berbamine-mediated ROS accumulation negatively regulated the NF-κB pathway to a certain degree. Consistent with our in vitro results, berbamine successfully inhibited tumor growth and blocked the NF-κB pathway in our xenograft model. To summarize, our data demonstrated that berbamine exerts antitumor effects via the ROS/NF-κB signaling axis in bladder cancer, which provides a basis for further comprehensive study and presents a potential candidate for clinical treatment strategies against bladder cancer.

Gas plasma-spurred wound healing is accompanied by regulation of focal adhesion, matrix remodeling, and tissue oxygenation

In response to injury, efficient migration of skin cells to rapidly close the wound and restore barrier function requires a range of coordinated processes in cell spreading and migration. Gas plasma technology produces therapeutic reactive species that promote skin regeneration by driving proliferation and angiogenesis. However, the underlying molecular mechanisms regulating gas plasma-aided cell adhesion and matrix remodeling essential for wound closure remain elusive. Here, we combined in vitro analyses in primary dermal fibroblasts isolated from murine skin with in vivo studies in a murine wound model to demonstrate that gas plasma treatment changed phosphorylation of signaling molecules such as focal adhesion kinase and paxillin α in adhesion-associated complexes. In addition to cell spreading and migration, gas plasma exposure affected cell surface adhesion receptors (e.g., integrinα5β1, syndecan 4), structural proteins (e.g., vinculin, talin, actin), and transcription of genes associated with differentiation markers of fibroblasts-to-myofibroblasts and epithelial-to-mesenchymal transition, cellular protrusions, fibronectin fibrillogenesis, matrix metabolism, and matrix metalloproteinase activity. Finally, we documented that gas plasma exposure increased tissue oxygenation and skin perfusion during ROS-driven wound healing. Altogether, these results provide critical insights into the molecular machinery of gas plasma-assisted wound healing mechanisms.

Verteporfin induces apoptosis and reduces the stem cell-like properties in Neuroblastoma tumour-initiating cells through inhibition of the YAP/TAZ pathway

Neuroblastoma is an embryonal malignancy of early childhood arising from the embryonic sympatho-adrenal lineage of the neural crest. About half of all cases are currently classified as high-risk of disease recurrence, with an overall survival rate of less than 40% at 5 years despite intensive therapy. Recent studies on matched primary tumours and at the relapse revealed downregulation of genes transcriptionally silenced by YAP as significant association with neuroblastoma relapse. Here, we evaluated the pharmacological targeting of YAP/TAZ with the YAP/TAZ-TEAD inhibitor Verteporfin (VP) in Tumour Initiating Cells (TICs) derived from High-Risk Neuroblastoma patients. VP treatment suppresses YAP/TAZ expression, induces apoptosis and causes the re-organization of the cytoskeleton reducing cells migration and clonogenic ability. Moreover, VP reduces the percentage of side population cells and ABC transporters involved in drug resistance, and the percentage of stem cell subpopulations CD133+ and CD44⁺ of TICs. Finally, we demonstrated that VP sensitizes TICs to the standard drugs used for neuroblastoma therapy etoposide and cis-platin opening the way to use VP as drug repositioning candidate for recurrent neuroblastoma.

ΕGFR/ERβ-Mediated Cell Morphology and Invasion Capacity Are Associated with Matrix Culture Substrates in Breast Cancer

Breast cancer accounts for almost one in four cancer diagnoses in women. Studies in breast cancer patients have identified several molecular markers, indicators of aggressiveness, which help toward more individual therapeutic approaches. In triple-negative breast cancer (TNBC), epidermal growth factor receptor (EGFR) overexpression is associated with increased metastatic potential and worst survival rates. Specifically, abnormal EGFR activation leads to altered matrix metalloproteinases' (MMPs) expression and, hence, extracellular matrix (ECM) degradation, resulting in induced migration and invasion. The use of matrix substrates for cell culture gives the opportunity to mimic the natural growth conditions of the cells and their microenvironment, as well as cell-cell and cell-matrix interactions. The aim of this study was to evaluate the impact of EGFR inhibition, estrogen receptor beta (ERβ) and different matrix substrates [type I collagen and fibronectin (FN)] on the functional properties, expression of MMPs and cell morphology of ERβ-positive TNBC cells and shERβ ones. Our results highlight EGFR as a crucial regulator of the expression and activity levels of MMPs, while ERβ emerges as a mediator of MMP7 and MT1-MMP expression. In addition, the EGFR/ERβ axis impacts the adhesion and invasion potential of breast cancer cells on collagen type I. Images obtained by scanning electron microscope (SEM) from cultures on the different matrix substrates revealed novel observations regarding various structures of breast cancer cells (filopodia, extravesicles, tunneling nanotubes, etc.). Moreover, the significant contribution of EGFR and ERβ in the morphological characteristics of these cells is also demonstrated, hence highlighting the possibility of dual pharmacological targeting.

Collagen Hybrid Formulations for the 3D Printing of Nanostructured Bone Scaffolds: An Optimized Genipin-Crosslinking Strategy

Bone-tissue regeneration induced by biomimetic bioactive materials is the most promising approach alternative to the clinical ones used to treat bone loss caused by trauma or diseases such as osteoporosis. The goal is to design nanostructured bioactive constructs able to reproduce the physiological environment: By mimicking the natural features of bone tissue, the cell behavior during the regeneration process may be addressed. At present, 3D-printing technologies are the only techniques able to design complex structures avoiding constraints of final shape and porosity. However, this type of biofabrication requires complex optimization of biomaterial formulations in terms of specific rheological and mechanical properties while preserving high biocompatibility. In this work, we combined nano-sized mesoporous bioactive glasses enriched with strontium ions with type I collagen, to formulate a bioactive ink for 3D-printing technologies. Moreover, to avoid the premature release of strontium ions within the crosslinking medium and to significantly increase the material mechanical and thermal stability, we applied an optimized chemical treatment using ethanol-dissolved genipin solutions. The high biocompatibility of the hybrid system was confirmed by using MG-63 and Saos-2 osteoblast-like cell lines, further highlighting the great potential of the innovative nanocomposite for the design of bone-like scaffolds.

Epithelial-to-mesenchymal transition and invadopodia markers in breast cancer: Lumican a key regulator

A great hallmark of breast cancer is the absence or presence of estrogen receptors ERα and ERβ, with a dominant role in cell proliferation, differentiation and cancer progression. Both receptors are related with Epithelial-to-Mesenchymal Transition (EMT) since there is a relation between ERs and extracellular matrix (ECM) macromolecules expression, and therefore, cell-cell and cell-ECM interactions. The endocrine resistance of ERα endows epithelial cells with increased aggressiveness and induces cell proliferation, resulting into a mesenchymal phenotype and an EMT status. ERα signaling may affect the transcriptional factors which govern EMT. Knockdown or silencing of ERα and ERβ in MCF-7 and MDA-MB-231 breast cancer cells respectively, provoked pivotal changes in phenotype, cellular functions, mRNA and protein levels of EMT markers, and consequently the EMT status. Mesenchymal cells owe their migratory and invasive properties to invadopodia, while in epithelial cells, lamellipodia and filopodia are mostly observed. Invadopodia, are actin-rich protrusions of plasma membrane, promoting proteolytic degradation of ECM and tumor invasion. Cortactin and MMP-14 govern the formation and principal functions of invadopodia. In vitro experiments proved that lumican inhibits cortactin and MMP-14 expression, alters the formation of lamellipodia and transforms mesenchymal cells into epithelial-like. Conclusively, lumican may inhibit or even reverse the several metastatic features that EMT endows in breast cancer cells. Therefore, a lumican-based anti-cancer therapy which will pharmacologically target and inhibit EMT might be interesting to be developed.

PEBP1/RKIP behavior: a mirror of actin-membrane organization

Phosphatidylethanolamine-binding protein 1 (PEBP1), a small 21 kDa protein, is implicated in several key processes of the living cell. The deregulation of PEBP1, especially its downregulation, leads to major diseases such as cancer and Alzheimer's disease. PEBP1 was found to interact with numerous proteins, especially kinases and GTPases, generally inhibiting their activity. To understand the basic functionality of this amazing small protein, we have considered several known processes that it modulates and we have discussed the role of each molecular target in these processes. Here, we propose that cortical actin organization, associated with membrane changes, is involved in the majority of the processes modulated by PEBP1. Furthermore, based on recent data, we summarize some key PEBP1-interacting proteins, and we report their respective functions and focus on their relationships with actin organization. We suggest that, depending on the cell status and environment, PEBP1 is an organizer of the actin-membrane composite material.

Multifaceted Roles of Caveolin-1 in Lung Cancer: A New Investigation Focused on Tumor Occurrence, Development and Therapy

Lung cancer is one of the most common and malignant cancers with extremely high morbidity and mortality in both males and females. Although traditional lung cancer treatments are fast progressing, there are still limitations. Caveolin-1 (Cav-1), a main component of caveolae, participates in multiple cellular events such as immune responses, endocytosis, membrane trafficking, cellular signaling and cancer progression. It has been found tightly associated with lung cancer cell proliferation, migration, apoptosis resistance and drug resistance. In addition to this, multiple bioactive molecules have been confirmed to target Cav-1 to carry on their anti-tumor functions in lung cancers. Cav-1 can also be a predictor for lung cancer patients’ prognosis. In this review, we have summarized the valuable research on Cav-1 and lung cancer in recent years and discussed the multifaceted roles of Cav-1 on lung cancer occurrence, development and therapy, hoping to provide new insights into lung cancer treatment.

Preclinical Evaluation of Ureidosulfamate Carbonic Anhydrase IX/XII Inhibitors in the Treatment of Cancers

Carbonic anhydrases (CAs) are a family of enzymes involved in the pH regulation of metabolically active cells/tissues. Upregulation of the CAIX/XII isoforms is associated with hypoxic tumours and clinically linked with malignant progression, treatment resistance and poor prognosis. The elucidation of the crystal structure of the catalytic domains of CAIX/XII provided the basis for the generation of CAIX/XII selective inhibitors based on the sulfonamide, sulfamate and coumarins chemical structures. Ureido-substituted benzenesulfonamide CAIX/XII inhibitors have shown significant potential, with U-104 (SLC-0111) currently present in clinical Phase I/II. Ureido-substituted sulfamate CAIX/XII inhibitors have received less attention despite encouraging preclinical test results. In triple-negative breast cancer (TNBC), ureidosulfamates revealed a significant antitumour (FC9-398A) and antimetastatic potential (S4). In small cell lung cancer (SCLC), a cancer cell type very sensitive to a dysregulation in CAIX signaling, S4 treatment was particularly effective when combined with cisplatin with no evidence of acquired cisplatin-resistance. These successful anticancer strategies should provide a solid basis for future studies on ureido-substituted sulfamates.

Cancer Cells Sense Fibers by Coiling on them in a Curvature-Dependent Manner

Metastatic cancer cells sense the complex and heterogeneous fibrous extracellular matrix (ECM) by formation of protrusions, and our knowledge of how cells physically recognize these fibers remains in its infancy. Here, using suspended ECM-mimicking isodiameter fibers ranging from 135 to 1,000 nm, we show that metastatic breast cancer cells sense fiber diameters differentially by coiling (wrapping-around) on them in a curvature-dependent manner, whereas non-tumorigenic cells exhibit diminished coiling. We report that coiling occurs at the tip of growing protrusions and the coil width and coiling rate increase in a curvature-dependent manner, but time to maximum coil width occurs biphasically. Interestingly, bundles of 135-nm diameter fibers recover coiling width and rate on 1,000-nm-diameter fibers. Coiling also coincides with curvature-dependent persistent and ballistic transport of endogenous granules inside the protrusions. Altogether, our results lay the groundwork to link biophysical sensing with biological signaling to quantitate pro- and anti-invasive fibrous environments.

Video Abstract

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Cells sense ECM-mimicking suspended fibers by coiling (wrapping around)

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Coiling occurs at the tip of growing protrusions in a curvature-dependent manner

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Non-tumorigenic cells exhibit diminished coiling compared with metastatic cells

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A bundle of small-diameter fibers recover coiling observed on a large-diameter fiber

CROCC-mutated rhabdoid colorectal carcinoma showing in intercellular spaces lamellipodia and cellular projections revealed by electron microscopy

BACKGROUND

Rhabdoid colorectal carcinoma (RC) is a rare lesion localized to the proximal colon of patients with a mean age at diagnosis of around 70 years. This tumor shows an aggressive behavior with an overall survival period shorter than 12 months. The diagnostic hallmark is the presence of rhabdoid cells. Alterations in chromatin remodeling (SMARCB1) and in the centrosome structure (CROCC) are reported in RC usually BRAFmut and MSI-H. RKO intestinal neoplastic cells culture (BRAFmut, SMARCB1wt, MSI-H) with CROCC knockdown exhibit rhabdoid features and develop prominent projections from the edge of the cell.

METHODS

Here, we investigated two cases of CROCCmutSMARCB1wt RC by scanning and transmission electron microscopy (SEM, TEM).

RESULTS

TEM confirmed the diagnostic presence of intermediate cytoplasmic filaments and nucleolar margination. SEM showed cellular protrusions (lamellipodia) in the intercellular spaces not evident at light microscopy.

CONCLUSIONS

These protrusions CROCC-related might represent the pathogenetic mechanism underlying the rhabdoid aggressive behavior, independently of tumor staging. To our knowledge, the SEM technique was applied in the study of this neoplasm for the first time.

P-Rex1 Overexpression Results in Aberrant Neuronal Polarity and Psychosis-Related Behaviors

Neuronal polarity is involved in multiple developmental stages, including cortical neuron migration, multipolar-to-bipolar transition, axon initiation, apical/basal dendrite differentiation, and spine formation. All of these processes are associated with the cytoskeleton and are regulated by precise timing and by controlling gene expression. The P-Rex1 (phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1) gene for example, is known to be important for cytoskeletal reorganization, cell motility, and migration. Deficiency of P-Rex1 protein leads to abnormal neuronal migration and synaptic plasticity, as well as autism-related behaviors. Nonetheless, the effects of P-Rex1 overexpression on neuronal development and higher brain functions remain unclear. In the present study, we explored the effect of P-Rex1 overexpression on cerebral development and psychosis-related behaviors in mice. In utero electroporation at embryonic day 14.5 was used to assess the influence of P-Rex1 overexpression on cell polarity and migration. Primary neuron culture was used to explore the effects of P-Rex1 overexpression on neuritogenesis and spine morphology. In addition, P-Rex1 overexpression in the medial prefrontal cortex (mPFC) of mice was used to assess psychosis-related behaviors. We found that P-Rex1 overexpression led to aberrant polarity and inhibited the multipolar-to-bipolar transition, leading to abnormal neuronal migration. In addition, P-Rex1 overexpression affected the early development of neurons, manifested as abnormal neurite initiation with cytoskeleton change, reduced the axon length and dendritic complexity, and caused excessive lamellipodia in primary neuronal culture. Moreover, P-Rex1 overexpression decreased the density of spines with increased height, width, and head area in vitro and in vivo. Behavioral tests showed that P-Rex1 overexpression in the mouse mPFC caused anxiety-like behaviors and a sensorimotor gating deficit. The appropriate P-Rex1 level plays a critical role in the developing cerebral cortex and excessive P-Rex1 might be related to psychosis-related behaviors.

Integrins: Moonlighting Proteins in Invadosome Formation

Invadopodia are actin-rich protrusions developed by transformed cells in 2D/3D environments that are implicated in extracellular matrix (ECM) remodeling and degradation. These structures have an undoubted association with cancer invasion and metastasis because invadopodium formation in vivo is a key step for intra/extravasation of tumor cells. Invadopodia are closely related to other actin-rich structures known as podosomes, which are typical structures of normal cells necessary for different physiological processes during development and organogenesis. Invadopodia and podosomes are included in the general term 'invadosomes,' as they both appear as actin puncta on plasma membranes next to extracellular matrix metalloproteinases, although organization, regulation, and function are slightly different. Integrins are transmembrane proteins implicated in cell-cell and cell-matrix interactions and other important processes such as molecular signaling, mechano-transduction, and cell functions, e.g., adhesion, migration, or invasion. It is noteworthy that integrin expression is altered in many tumors, and other pathologies such as cardiovascular or immune dysfunctions. Over the last few years, growing evidence has suggested a role of integrins in the formation of invadopodia. However, their implication in invadopodia formation and adhesion to the ECM is still not well known. This review focuses on the role of integrins in invadopodium formation and provides a general overview of the involvement of these proteins in the mechanisms of metastasis, taking into account classic research through to the latest and most advanced work in the field.

Cathepsin B Is Upregulated and Mediates ECM Degradation in Colon Adenocarcinoma HT29 Cells Overexpressing Snail

During tumor development and ongoing metastasis the acquisition of mesenchymal cell traits by epithelial carcinoma cells is achieved through a programmed phenotypic shift called the epithelial-to-mesenchymal transition, EMT. EMT contributes to increased cancer cell motility and invasiveness mainly through invadosomes, the adhesion structures that accompany the mesenchymal migration. The invadosomes and their associated proteases restrict protease activity to areas of the cell in direct contact with the ECM, thus precisely controlling cell invasion. Our data prove that Snail-overexpressing HT-29 cells that imitate the phenotype of colon cancer cells in the early stage of the EMT showed an increase in the expression and pericellular activity of cathepsin B. It appears that the pericellular localization of cathepsin B, also observed in colon and rectum adenocarcinoma tissue samples, plays a key role in its function.

Putting VE-cadherin into JAIL for junction remodeling

Junction dynamics of endothelial cells are based on the integration of signal transduction, cytoskeletal remodeling and contraction, which are necessary for the formation and maintenance of monolayer integrity, but also enable repair and regeneration. The VE-cadherin–catenin complex forms the molecular basis of the adherence junctions and cooperates closely with actin filaments. Several groups have recently described small actin-driven protrusions at the cell junctions that are controlled by the Arp2/3 complex, contributing to cell junction regulation. We identified these protrusions as the driving force for VE-cadherin dynamics, as they directly induce new VE-cadherin-mediated adhesion sites, and have accordingly referred to these structures as junction-associated intermittent lamellipodia (JAIL). JAIL extend over only a few microns and thus provide the basis for a subcellular regulation of adhesion. The local (subcellular) VE-cadherin concentration and JAIL formation are directly interdependent, which enables autoregulation. Therefore, this mechanism can contribute a subcellularly regulated adaptation of cell contact dynamics, and is therefore of great importance for monolayer integrity and relative cell migration during wound healing and angiogenesis, as well as for inflammatory responses. In this Review, we discuss the mechanisms and functions underlying these actin-driven protrusions and consider their contribution to the dynamic regulation of endothelial cell junctions.

Extracellular Vesicles Released by Glioblastoma Cells Stimulate Normal Astrocytes to Acquire a Tumor-Supportive Phenotype Via p53 and MYC Signaling Pathways

The role of astrocytes is becoming increasingly important to understanding how glioblastoma (GBM) tumor cells diffusely invade the brain. Yet, little is known of the contribution of extracellular vesicle (EV) signaling in GBM/astrocyte interactions. We modeled GBM-EV signaling to normal astrocytes in vitro to assess whether this mode of intercellular communication could support GBM progression. EVs were isolated and characterized from three patient-derived GBM stem cells (NES⁺/CD133⁺) and their differentiated (diff) progeny cells (NES⁻/CD133⁻). Uptake of GBM-EVs by normal primary astrocytes was confirmed by fluorescence microscopy, and changes in astrocyte podosome formation and gelatin degradation were measured. Quantitative mass spectrometry-based proteomics was performed on GBM-EV stimulated astrocytes. Interaction networks were generated from common, differentially abundant proteins using Ingenuity® (Qiagen Bioinformatics) and predicted upstream regulators were tested by qPCR assays. Podosome formation and Cy3-gelatin degradation were induced in astrocytes following 24-h exposure to GBM-stem and -diff EVs, with EVs released by GBM-stem cells eliciting a greater effect. More than 1700 proteins were quantified, and bioinformatics predicted activations of MYC, NFE2L2, FN1, and TGFβ1 and inhibition of TP53 in GBM-EV stimulated astrocytes that were then confirmed by qPCR. Further qPCR studies identified significantly decreased Δ133p53 and increased p53β in astrocytes exposed to GBM-EVs that might indicate the acquisition of a pro-inflammatory, tumor-promoting senescence-associated secretory phenotype (SASP). Inhibition of TP53 and activation of MYC signaling pathways in normal astrocytes exposed to GBM-EVs may be a mechanism by which GBM manipulates astrocytes to acquire a phenotype that promotes tumor progression.

ERK phosphorylation functions in invadopodia formation in tongue cancer cells in a novel silicate fibre-based 3D cell culture system

To screen for additional treatment targets against tongue cancer, we evaluated the contributions of extracellular signal-related kinase (ERK), AKT and ezrin in cancer development. Immunohistochemical staining showed that ERK and ezrin expressions were significantly higher in invasive squamous cell carcinoma than in carcinoma in situ. To investigate the roles of ERK and ezrin in cancer development, we used the non-woven silica fibre sheet Cellbed^TM with a structure resembling the loose connective tissue morphology in a novel 3D culture system. We confirmed that the 3D system using Cellbed^TM accurately mimicked cancer cell morphology in vivo. Furthermore, cell projections were much more apparent in 3D-cultured tongue cancer cell lines than in 2D cultures. Typically, under conventional 2D culture conditions, F-actin and cortactin are colocalized in the form of puncta within cells. However, in the 3D-cultured cells, colocalization was mainly observed at the cell margins, including the projections. Projections containing F-actin and cortactin colocalization were predicted to be invadopodia. Although suppressing ezrin expression with small interfering RNA transfection caused no marked changes in morphology, cell projection formation was decreased, and the tumour thickness in vertical sections after 3D culture was markedly decreased after suppressing ERK activity because both the invasion ability and proliferation were inhibited. An association between cortactin activation as well as ERK activity and invadopodia formation was detected. Our novel 3D culture systems using Cellbed™ are simple and useful for in vitro studies before conducting animal experiments. ERK contributes to tongue cancer development by increasing both cancer cell proliferation and migration via cortactin activation.

Extracellular signal-regulated kinases (ERKs) are enzymes that are involved in a variety of cell functions, and one in vitro study suggests that ERKs play a role in tongue cancer development by increasing cancer cell proliferation and migration. Using a novel 3-D cell culture system called Cellbed to mimic cancer cell morphology, a team headed by Ken-ichi Mukaisho at Shiga University of Medical Science, Japan found that ERKs activate cortactin (a protein located in the cell cytoplasm) and contribute to the formation of invadopodia (invasive cell protrusions associated with cancer cells) in tongue cancer cells and tumor development. The authors conclude that experimental 3-D cell culture systems employing Cellbed are easily implemented and useful for in vitro studies before conducting animal experiments and that they can be widely applied in cancer research.

Promoter Methylation-Regulated miR-145-5p Inhibits Laryngeal Squamous Cell Carcinoma Progression by Targeting FSCN1

Laryngeal squamous cell carcinoma (LSCC) is a common form of head and neck cancer with poor prognosis. However, the mechanism underlying the pathogenesis of LSCC remains unclear. Here, we demonstrated increased expression of fascin actin-bundling protein 1 (FSCN1) and decreased expression of microRNA-145-5p (miR-145-5p) in a clinical cohort of LSCC. Luciferase assay revealed that miR-145-5p is a negative regulator of FSCN1. Importantly, low miR-145-5p expression was correlated with TNM (tumor, node, metastasis) status and metastasis. Moreover, cases with low miR-145-5p/high FSCN1 expression showed poor prognosis, and these characteristics together served as independent prognostic indicators of survival. Gain- and loss-of-function studies showed that miR-145-5p overexpression or FSCN1 knockdown inhibited LSCC migration, invasion, and growth by suppressing the epithelial-mesenchymal transition along with inducing cell-cycle arrest and apoptosis. Additionally, hypermethylation of the miR-145-5p promoter suggested that repression of miR-145-5p arises through epigenetic inactivation. LSCC tumor growth in vivo could be inhibited by using miR-145-5p agomir or FSCN1 small interfering RNA (siRNA), which highlights the potential for clinical translation. Collectively, our findings indicate that miR-145-5p plays critical roles in inhibiting the progression of LSCC by suppressing FSCN1. Both miR-145-5p and FSCN1 are important potential prognostic markers and therapeutic targets for LSCC.

Changes in Vasodilator-Stimulated Phosphoprotein Phosphorylation, Profilin-1, and Cofilin-1 in Accreta and Protection by DHA

Accreta and gestational trophoblastic disease (ie, choriocarcinoma) are placental pathologies characterized by hyperproliferative and invasive trophoblasts. Cellular proliferation, migration, and invasion are heavily controlled by actin-binding protein (ABP)-mediated actin dynamics. The ABP vasodilator-stimulated phosphoprotein (VASP) carries key regulatory role. Profilin-1, cofilin-1, and VASP phosphorylated at Ser157 (pVASP-S157) and Ser239 (pVASP-S239) are ABPs that regulate actin polymerization and stabilization and facilitate cell metastases. Docosahexaenoic acid (DHA) inhibits cancer cell migration and proliferation. We hypothesized that analogous to malignant cells, ABPs regulate these processes in extravillous trophoblasts (EVTs), which exhibit aberrant expression in placenta accreta. Placental-myometrial junction biopsies of histologically confirmed placenta accreta had significantly increased immunostaining levels of cofilin-1, VASP, pVASP-S239, and F-actin. Treatment of choriocarcinoma-derived trophoblast (BeWo) cells with DHA (30 µM) for 24 hours significantly suppressed proliferation, migration, and pVASP-S239 levels and altered protein profiles consistent with increased apoptosis. We concluded that in accreta changes in the ABP expression profile were a response to restore homeostasis by counteracting the hyperproliferative and invasive phenotype of the EVT. The observed association between VASP phosphorylation, apoptosis, and trophoblast proliferation and migration suggest that DHA may offer a therapeutic solution for conditions where EVT is hyperinvasive.