Focal adhesion kinase as a regulator of cell tension in the progression of cancer

STAT3 mediates ECM stiffness-dependent progression in ovarian cancer

The treatment of ovarian cancer remains a medical challenge and its malignant progression is connected with obvious changes in both tissue and cell stiffness. However, the accurate mechanical-responsive molecules and mechanism remains unclear in ovarian cancer. Based on our previous results combined with the crucial regulatory role of STAT3 in the malignant progression of various cancer types, we want to investigate the relationship between STAT3 and matrix stiffness in ovarian cancer and further explore the potential mechanisms. Collagen-coated polyacrylamide gels (1, 6, and 60 kPa) were prepared to mimic soft or hard matrix stiffness. Western blotting, qRT-PCR, flow cytometry, IHC, EdU assays, and TEM were used to evaluate the effect of STAT3 in vitro under different matrix stiffnesses. Furthermore, a BALB/c nude mouse model was established to assess the relationship in vivo. Our results confirmed the differential expression of STAT3/p-STAT3 not only in normal and malignant ovarian tissues but also under different matrix stiffnesses. Furthermore, we verified that STAT3 was a mechanically responsive gene both in vitro and in vivo, and the mechanical response was carried out by altering the migration-related molecules (TNFAIP1) and adhesion-related molecules (LPXN, CNN3). The novel findings suggest that STAT3, a potential therapeutic target for clinical diagnosis and treatment, is a mechanically responsive gene that responds to matrix stiffness, particularly regulation in migration and adhesion in the progression of ovarian cancer.

The key role of matrix stiffness in colorectal cancer immunotherapy: mechanisms and therapeutic strategies

Increased matrix stiffness within the colorectal cancer (CRC) tumor microenvironment (TME) has emerged as a pivotal determinant of immunotherapy outcomes. This review discusses the role of aberrant extracellular matrix (ECM) deposition and cross-linking in augmenting matrix stiffness, a phenomenon that not only scaffolds the tumor architecture but also contributes to tumorigenicity and immunologic evasion. Herein, we critically appraise the influence of matrix stiffness on the immunotherapeutic landscape of CRC, focusing on its capacity to impede therapeutic efficacy by modulating immune cell infiltration, activation, and functional performance. The review explores the molecular dynamics whereby matrix stiffness prompts tumor evolution, highlighting the integral role of integrin signaling, cancer-associated fibroblasts (CAFs), and the process of epithelial-mesenchymal transition (EMT). We bring to the fore the paradoxical impact of an indurated ECM on immune effector cells, chiefly T cells and macrophages, which are indispensable for immune surveillance and the execution of immunotherapeutic strategies, yet are markedly restrained by a fibrotic matrix. Furthermore, we examine how matrix stiffness modulates immune checkpoint molecule expression, thereby exacerbating the immunosuppressive milieu within the TME and attenuating immunotherapeutic potency. Emergent therapeutic regimens targeting matrix stiffness-including matrix modulators, inhibitors of mechanotransduction signaling pathways, and advanced biomaterials that mimic the ECM-proffer novel modalities to potentiate immunotherapy responsiveness. By refining the ECM's biomechanical attributes, the mechanical barriers posed by the tumor stroma can be improved, facilitating robust immune cell penetration and activity, and thereby bolstering the tumor's susceptibility to immunotherapy. Ongoing clinical trials are evaluating these innovative treatments, particularly in combination with immunotherapies, with the aim of enhancing clinical outcomes for CRC patients afflicted by pronounced matrix stiffness.

Bucidarasin A suppresses the proliferation and metastasis of HCC by targeting the FAK and STAT3 pathways

Hepatocellular carcinoma (HCC) is a significant global health concern, with high rates of morbidity and mortality. Bucidarasin A, a natural diterpenoid, has been shown to exert notable cytotoxic effects across a range of tumor cell lines. However, the underlying mechanisms responsible for this cytotoxicity remain unclear. In this study, we sought to elucidate the antitumor mechanisms of bucidarasin A, a natural diterpenoid derived from Casearia graveolens, with a particular focus on its effects on HCC. Furthermore, we employed surface plasmon resonance (SPR), molecular docking, and cellular thermal shift assay (CETSA) to gain further insight into the target protein of bucidarasin A. Our findings revealed that bucidarasin A exhibited pronounced cytotoxicity towards HepG2 cells. In vitro analysis indicated that bucidarasin A interrupted the cell cycle at the S phase and inhibited the proliferation and metastasis of HepG2 cells by modulating the FAK and STAT3 signaling pathways. Moreover, in vivo studies demonstrated that bucidarasin A not only exhibited antitumor effects but also impeded neovascularization, a finding that was corroborated by SPR interactions between vascular endothelial growth factor (VEGF) and bucidarasin A. This research substantiated that bucidarasin A, a clerodane diterpenoid, held promise as a therapeutic candidate against HCC, showcasing substantial antitumor efficacy both in vitro and in vivo through direct targeting of the STAT3 and FAK signaling pathways.

Regulation of intracellular cAMP levels in osteocytes by mechano-sensitive focal adhesion kinase via PDE8A

Osteocytes are the primary mechano-sensitive cell type in bone. Mechanical loading is sensed across the dendritic projections of osteocytes leading to transient reductions in focal adhesion kinase (FAK) activity. Knowledge regarding the signaling pathways downstream of FAK in osteocytes is incomplete. We performed tyrosine-focused phospho-proteomic profiling in osteocyte-like Ocy454 cells to identify FAK substrates. Gsα, parathyroid hormone receptor (PTH1R), and phosphodiesterase 8A (PDE8A), all proteins associated with cAMP signaling, were found as potential FAK targets based on their reduced tyrosine phosphorylation in both FAK- deficient or FAK inhibitor treated cells. Real time monitoring of intracellular cAMP levels revealed that FAK pharmacologic inhibition or gene deletion increased basal and GPCR ligand-stimulated cAMP levels and downstream phosphorylation of protein kinase A substrates. Mutating FAK phospho-acceptor sites in Gsα and PTH1R had no effect on PTH- or FAK inhibitor-stimulated cAMP levels. Since FAK inhibitor treatment augmented cAMP levels even in the presence of forskolin, we focused on potential FAK substrates downstream of cAMP generation. Indeed, PDE8A inhibition mimicked FAK inhibition at the level of increased cAMP, PKA activity, and expression of cAMP-regulated target genes. In vitro kinase assay showed that PDE8A is directly phosphorylated by FAK while immunoprecipitation assays revealed intracellular association between FAK and PDE8A. Thus, FAK inhibition in osteocytes acts synergistically with signals that activate adenylate cyclase to increase intracellular cAMP. Mechanically-regulated FAK can modulate intracellular cAMP levels via effects on PDE8A. These data suggest a novel signal transduction mechanism that mediates crosstalk between mechanical and cAMP-linked hormonal signaling in osteocytes.

Quercetin Induces Mitochondrial Apoptosis and Downregulates Ganglioside GD3 Expression in Melanoma Cells

Malignant melanoma represents a form of skin cancer characterized by a bleak prognosis and heightened resistance to traditional therapies. Quercetin has demonstrated notable anti-carcinogenic, anti-inflammatory, anti-oxidant, and pharmacological effects across various cancer types. However, the intricate relationship between quercetin's anti-cancer properties and ganglioside expression in melanoma remains incompletely understood. In this study, quercetin manifests specific anti-proliferative, anti-migratory, and cell-cycle arrest effects, inducing mitochondrial dysfunction and apoptosis in two melanoma cancer cell lines. This positions quercetin as a promising candidate for treating malignant melanoma. Moreover, our investigation indicates that quercetin significantly reduces the expression levels of ganglioside GD3 and its synthetic enzyme. Notably, this reduction is achieved through the inhibition of the FAK/paxillin/Akt signaling pathway, which plays a crucial role in cancer development. Taken together, our findings suggest that quercetin may be a potent anti-cancer drug candidate for the treatment of malignant melanoma.

Cell volume expansion and local contractility drive collective invasion of the basement membrane in breast cancer

Breast cancer becomes invasive when carcinoma cells invade through the basement membrane (BM)-a nanoporous layer of matrix that physically separates the primary tumour from the stroma. Single cells can invade through nanoporous three-dimensional matrices due to protease-mediated degradation or force-mediated widening of pores via invadopodial protrusions. However, how multiple cells collectively invade through the physiological BM, as they do during breast cancer progression, remains unclear. Here we developed a three-dimensional in vitro model of collective invasion of the BM during breast cancer. We show that cells utilize both proteases and forces-but not invadopodia-to breach the BM. Forces are generated from a combination of global cell volume expansion, which stretches the BM, and local contractile forces that act in the plane of the BM to breach it, allowing invasion. These results uncover a mechanism by which cells collectively interact to overcome a critical barrier to metastasis.

Comprehensive DNA methylation profiling by MeDIP-NGS identifies potential genes and pathways for epithelial ovarian cancer

Ovarian cancer, among all gynecologic malignancies, exhibits the highest incidence and mortality rate, primarily because it is often presents with non-specific or no symptoms during its early stages. For the advancement of Ovarian Cancer Diagnosis, it is crucial to identify the potential molecular signatures that could significantly differentiate between healthy and ovarian cancerous tissues and can be used further as a diagnostic biomarker for detecting ovarian cancer. In this study, we investigated the genome-wide methylation patterns in ovarian cancer patients using Methylated DNA Immunoprecipitation (MeDIP-Seq) followed by NGS. Identified differentially methylated regions (DMRs) were further validated by targeted bisulfite sequencing for CpG site-specific methylation profiles. Furthermore, expression validation of six genes by Quantitative Reverse Transcriptase-PCR was also performed. Out of total 120 differentially methylated genes (DMGs), 68 genes were hypermethylated, and 52 were hypomethylated in their promoter region. After analysis, we identified the top 6 hub genes, namely POLR3B, PLXND1, GIGYF2, STK4, BMP2 and CRKL. Interestingly we observed Non-CpG site methylation in the case of POLR3B and CRKL which was statistically significant in discriminating ovarian cancer samples from normal controls. The most significant pathways identified were focal adhesion, the MAPK signaling pathway, and the Ras signaling pathway. Expression analysis of hypermethylated genes was correlated with the downregulation of the genes. POLR3B and GIGYF2 turned out to be the novel genes associated with the carcinogenesis of EOC. Our study demonstrated that methylation profiling through MeDIP-sequencing has effectively identified six potential hub genes and pathways that might exacerbate our understanding of underlying molecular mechanisms of ovarian carcinogenesis.

The spatiotemporal heterogeneity of the biophysical microenvironment during hematopoietic stem cell development: from embryo to adult

Hematopoietic stem cells (HSCs) with the ability to self-renew and differentiate are responsible for maintaining the supply of all types of blood cells. The complex and delicate microenvironment surrounding HSCs is called the HSC niche and can provide physical, chemical, and biological stimuli to regulate the survival, maintenance, proliferation, and differentiation of HSCs. Currently, the exploration of the biophysical regulation of HSCs remains in its infancy. There is evidence that HSCs are susceptible to biophysical stimuli, suggesting that the construction of engineered niche biophysical microenvironments is a promising way to regulate the fate of HSCs in vitro and ultimately contribute to clinical applications. In this review, we introduced the spatiotemporal heterogeneous biophysical microenvironment during HSC development, homeostasis, and malignancy. Furthermore, we illustrated how these biophysical cues contribute to HSC behaviors, as well as the possible mechanotransduction mechanisms from the extracellular microenvironment into cells. Comprehending the important functions of these biophysical regulatory factors will provide novel approaches to resolve clinical problems.

Cellular and Molecular Mechanisms of the Tumor Stroma in Colorectal Cancer: Insights into Disease Progression and Therapeutic Targets

Colorectal cancer (CRC) is a major health burden worldwide and is the third most common type of cancer. The early detection and diagnosis of CRC is critical to improve patient outcomes. This review explores the intricate interplay between the tumor microenvironment, stromal interactions, and the progression and metastasis of colorectal cancer. The review begins by assessing the gut microbiome's influence on CRC development, emphasizing its association with gut-associated lymphoid tissue (GALT). The role of the Wnt signaling pathway in CRC tumor stroma is scrutinized, elucidating its impact on disease progression. Tumor budding, its effect on tumor stroma, and the implications for patient prognosis are investigated. The review also identifies conserved oncogenic signatures (COS) within CRC stroma and explores their potential as therapeutic targets. Lastly, the seed and soil hypothesis is employed to contextualize metastasis, accentuating the significance of both tumor cells and the surrounding stroma in metastatic propensity. This review highlights the intricate interdependence between CRC cells and their microenvironment, providing valuable insights into prospective therapeutic approaches targeting tumor-stroma interactions.

Remodeling of the focal adhesion complex by hydrogen-peroxide-induced senescence

Cellular senescence is a phenotype characterized by cessation of cell division, which can be caused by exhaustive replication or environmental stress. It is involved in age-related pathophysiological conditions and affects both the cellular cytoskeleton and the prime cellular mechanosensors, focal adhesion complexes. While the size of focal adhesions increases during senescence, it is unknown if and how this is accompanied by a remodeling of the internal focal adhesion structure. Our study uses metal-induced energy transfer to study the axial dimension of focal adhesion proteins from oxidative-stress-induced senescent cells with nanometer precision, and compares these to unstressed cells. We influenced cytoskeletal tension and the functioning of mechanosensitive ion channels using drugs and studied the combined effect of senescence and drug intervention on the focal adhesion structure. We found that H2O2-induced restructuring of the focal adhesion complex indicates a loss of tension and altered talin complexation. Mass spectroscopy-based proteomics confirmed the differential regulation of several cytoskeletal proteins induced by H2O2 treatment.

Out of the cycle: Impact of cell cycle aberrations on cancer metabolism and metastasis

The use of cell cycle inhibitors has necessitated a better understanding of the cell cycle in tumor biology to optimize the therapeutic approach. Cell cycle aberrations are common in cancers, and it is increasingly acknowledged that these aberrations exert oncogenic effects beyond the cell cycle. Multiple facets such as cancer metabolism, immunity and metastasis are also affected, all of which are beyond the effect of cell proliferation alone. This review comprehensively summarized the important recent findings and advances in these interrelated processes. In cancer metabolism, cell cycle regulators can modulate various pathways in aerobic glycolysis, glucose uptake and gluconeogenesis, mainly through transcriptional regulation and kinase activities. Amino acid metabolism is also regulated through cell cycle progression. On cancer metastasis, metabolic plasticity, immune evasion, tumor microenvironment adaptation and metastatic site colonization are intricately related to the cell cycle, with distinct regulatory mechanisms at each step of invasion and dissemination. Throughout the synthesis of current understanding, knowledge gaps and limitations in the literature are also highlighted, as are new therapeutic approaches such as combinational therapy and challenges in tackling emerging targeted therapy resistance. A greater understanding of how the cell cycle modulates diverse aspects of cancer biology can hopefully shed light on identifying new molecular targets by harnessing the vast potential of the cell cycle.

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.

pH-Selective Reactions to Selectively Reduce Cancer Cell Proliferation: Effect of CaS Nanostructures in Human Skin Melanoma and Benign Fibroblasts

An acidic extracellular pH value (pHe) is characteristic of many cancers, in contrast to the physiologic pHe found in most benign cells. This difference in pH offers a unique opportunity to design and engineer chemicals that can be employed for pH-selective reactions in the extracellular fluid of cancer cells. The viability of human skin melanoma and corresponding fibroblasts exposed to CaS dispersions is reported. The viability of melanoma cells decreases with CaS dispersion concentration and reaches 57% at 3%, a value easily distinguishable from melanoma control experiments. In contrast, the viability of benign fibroblasts remains nearly constant within experimental error over the range of dispersion concentrations studied. The CaS dispersions facilitate vinculin delocalization in the cytoplasmic fluid, a result consistent with improved focal adhesion kinase (FAK) regulation in melanoma cells. Thermodynamic considerations are consistent with the formation ofH 2 S from CaS in the presence of protons. The thermodynamic prediction is verified in independent experiments with solid CaS and acidic aqueous solutions. The amount ofH 2 S formed decreases with pH. An activation energy for the process of (30 ± 10) kJ/mol in the temperature range of 280 to 330 K is estimated from initial rate measurements as a function of temperature. The total Gibbs energy minimization approach was employed to establish the distribution of sulfides-includingH 2 S in the gas and aqueous phases-from the dissociation of CaS as a function of pH to mimic physiologically relevant pH values. Theoretical calculations suggest that partially protonated CaS in solution can be stable until the sulfur atom bonds to two hydrogen atoms, resulting in the formation of Ca2+ andH 2 S , which can be solvated and/or released to the gas phase. Our results are consistent with a model in which CaS is dissociated in the extracellular fluid of melanoma cells selectively. The results are discussed in the context of the potential biomedical applications of CaS dispersions in cancer therapies.

Adipose-derived stem cells with miR-150-5p inhibition laden in hydroxyapatite/tricalcium phosphate ceramic powders promote osteogenesis via regulating Notch3 and activating FAK/ERK and RhoA

Adipose-derived mesenchymal stem cells (ADSCs) are multipotent stromal cells and play huge role in forming and repairing bone tissues. Emerging evidence shows that MicroRNAs (miRNAs) are involved in ADSCs differentiation. Here, we explored the role of miR-150-5p and its related mechanisms in ADSCs osteogenesis. Real-time PCR was used to determine miR-150-5p expression during ADSCs osteogenesis. miR-150-5p inhibitors, miR-150-5p ADV or short hairpin RNA (shRNA) of Notch3 were transfected to ADSCs for analyzing the effects on osteogenesis. The mixture of hydroxyapatite/tricalcium phosphate (HA/TCP) ceramic powders and transfected ADSCs was implanted into BALB/C nude mice. Micro-CT and histological methods were performed to evaluate the new bone formation. Compared with negative control (NC) and miR-150-5p overexpression, inhibition of miR-150-5p increased ADSCs osteogenesis by regulating Notch3. MiR-150-5p overexpression decreased the expression of pFAK, pERK1/2, and RhoA, while these were up-regulated when miR-150-5p was inhibited, or notch3 was silenced. Furthermore, miR-150-5p inhibition partially reversed the suppression effect of notch3 knockdown on osteogenesis in vitro and in vivo. This study demonstrated the critical function of miR-150-5p during osteogenesis. The combination of ADSCs with miR-150-5p inhibition and HA/TCP might be a promising strategy for bone damage repair. STATEMENT OF SIGNIFICANCE: Osteoporosis is a common chronic metabolic bone disease in humans. Bone tissue engineering based on mesenchymal stem cells, biomaterials, and growth factors, provides a promising way to treat osteoporosis and bone defects. ADSCs commonly differentiate into adipose cells, they can also differentiate into osteogenic cell lineages. Nucleic acids and protein have usually been considered as regulators of ADSCs osteogenic differentiation. In the current study, we demonstrated the combination of ADSCs with miR-150-5p inhibition and hydroxyapatite/tricalcium phosphate ceramic powders enhanced bone regeneration. Furthermore, miR-150-5p/Notch3 axis regulating osteogenesis via the FAK/ERK1/2 and RhoA pathway was assessed. The current study showed the application of ADSCs in bone regeneration might be a promising strategy for osteoporosis and bone damage repairing.

S100A10 Promotes Pancreatic Ductal Adenocarcinoma Cells Proliferation, Migration and Adhesion through JNK/LAMB3-LAMC2 Axis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors, characterized by diagnosis at an advanced stage and a poor prognosis. As a member of the S100 protein family, S100A10 regulates multiple biological functions related to cancer progression and metastasis. However, the role of S100A10 in PDAC is still not completely elucidated. In this study, we reported that S100A10 was significantly up-regulated in PDAC tissue and associated with a poor prognosis by integrated bioinformatic analysis and human PDAC tissue samples. In vitro, down-regulation of S100A10 reduced the proliferation, migration, and adhesion of PDAC cell lines, whereas up-regulation of S100A10 showed the opposite effect. Furthermore, LAMB3 was proved to be activated by S100A10 using RNA-sequencing and western blotting. The effect of LAMB3 on the proliferation, migration, and adhesion of PDAC cells was similar to that of S100A10. Up-regulation or down-regulation of LAMB3 could reverse the corresponding effect of S100A10. Moreover, we validated S100A10 activates LAMB3 through the JNK pathway, and LAMB3 was further proved to interact with LAMC2. Mice-bearing orthotopic pancreatic tumors showed that S100A10 knocked-down PANC-1 cells had a smaller tumor size than the control group. In conclusion, S100A10 promotes PDAC cells proliferation, migration, and adhesion through JNK/LAMB3-LAMC2 axis.

Biology of cancer; from cellular and molecular mechanisms to developmental processes and adaptation

Cancer research has been largely focused on the cellular and molecular levels of investigation. Recent data show that not only the cell but also the extracellular matrix plays a major role in the progression of malignancy. In this way, the cells and the extracellular matrix create a specific local microenvironment that supports malignant development. At the same time, cancer implies a systemic evolution which is closely related to developmental processes and adaptation. Consequently, there is currently a real gap between the local investigation of cancer at the microenvironmental level, and the pathophysiological approach to cancer as a systemic disease. In fact, the cells and the matrix are not only complementary structures but also interdependent components that act synergistically. Such relationships lead to cell-matrix integration, a supracellular form of biological organization that supports tissue development. The emergence of this supracellular level of organization, as a structure, leads to the emergence of the supracellular control of proliferation, as a supracellular function. In humans, proliferation is generally involved in developmental processes and adaptation. These processes suppose a specific configuration at the systemic level, which generates high-order guidance for local supracellular control of proliferation. In conclusion, the supracellular control of proliferation act as an interface between the downstream level of cell division and differentiation, and upstream level of developmental processes and adaptation. Understanding these processes and their disorders is useful not only to complete the big picture of malignancy as a systemic disease, but also to open new treatment perspectives in the form of etiopathogenic (supracellular or informational) therapies.

3D Ti3C2Tx MXene-Matrigel with Electroacoustic Stimulation to Promote the Growth of Spiral Ganglion Neurons

Cochlear implantation has become the most effective treatment method for patients with profound and total hearing loss. However, its therapeutic efficacy is dependent on the number and normal physiological function of cochlear implant-targeted spiral ganglion neurons (SGNs). Electrical stimulation can be used as an effective cue to regulate the morphology and function of excitatory cells. Therefore, it is important to develop an efficient cochlear implant electroacoustic stimulation (EAS) system to study the behavior of SGNs. In this work, we present an electrical stimulation system constructed by combining a cochlear implant and a conductive Ti₃C₂T_x MXene-matrigel hydrogel. SGNs were cultured in the Ti₃C₂T_x MXene-matrigel hydrogel and exposed to electrical stimulation transduced by the cochlear implant. It was demonstrated that low-frequency stimulation promoted the growth cone development and neurite outgrowth of SGNs as well as signal transmission between cells. This work may have potential value for the clinical application of the Ti₃C₂T_x MXene hydrogel to optimize the postoperative listening effect of cochlear implantation and benefit people with sensorineural hearing loss.

What protein kinases are crucial for acantholysis and blister formation in pemphigus vulgaris? A systematic review

Pemphigus vulgaris (PV) is a potentially fatal autoimmune blistering disease characterized by cell-cell detachment (or acantholysis) and blister formation. While the signaling mechanisms that associate with skin/mucosal blistering are being elucidated, specific treatment strategies targeting PV-specific pathomechanisms, particularly kinase signaling, have yet to be established. Hence, the aim of this review was to systematically evaluate molecules in the class of kinases that are essential for acantholysis and blister formation and are therefore candidates for targeted therapy. English articles from PubMed and Scopus databases were searched, and included in vitro, in vivo, and human studies that investigated the role of kinases in PV. We selected studies, extracted data and assessed risk of bias in duplicates and the results were reported according to the methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The risk of bias assessment was performed on in vivo studies utilizing SYRCLE's risk of bias tool. Thirty-five studies were included that satisfied the pathogenicity criterion of kinases in PV, the vast majority being experimental models that used PV sera (n = 13) and PV-IgG (n = 22). Inhibition of kinase activity (p38MAPK, PKC, TK, c-Src, EGFR, ERK, mTOR, BTK, and CDK2) was achieved mostly by pharmacological means. Overall, we found substantial evidence that kinase inhibition reduced PV-associated phosphorylation events and keratinocyte disassociation, prevented acantholysis, and blocked blister formation. However, the scarce adherence to standardized reporting systems and the experimental protocols/models used did limit the internal and external validity of these studies. In summary, this systematic review highlighted the pathogenic intracellular events mediated by kinases in PV acantholysis and presented kinase signaling as a promising avenue for translational research. In particular, the molecules identified and discussed in this study represent potential candidates for the development of mechanism-based interventions in PV.

Osteogenesis-Inducing Chemical Cues Enhance the Mechanosensitivity of Human Mesenchymal Stem Cells for Osteogenic Differentiation on a Microtopographically Patterned Surface

Mechanical cues are widely used for regulating cell behavior because of their overarching, extensive, and non-invasive advantages. However, unlike chemical cues, mechanical cues are not efficient enough to determine cell fate independently and improving the mechanosensitivity of cells is rather challenging. In this study, the combined effect of chemical and mechanical cues on the osteogenic differentiation of human mesenchymal stem cells is examined. These results show that chemical cues such as the presence of an osteogenic medium, induce cells to secrete more collagen, and induce integrin for recruiting focal adhesion proteins that mature and cascade a series of events with the help of the mechanical force of the scaffold material. High-resolution, highly ordered hollow-micro-frustum-arrays using double-layer lithography, combined with modified methacrylate gelatin loaded with pre-defined soluble chemicals to provide both chemical and mechanical cues to cells. This approach ultimately facilitates the achievement of cellular osteodifferentiation and enhances bone repair efficiency in a model of femoral fracture in vivo in mice. Moreover, the results also reveal these pivotal roles of Integrin α2/Focal adhesion kinase/Ras homolog gene family member A/Large Tumor Suppressor 1/Yes-associated protein in human mesenchymal stem cells osteogenic differentiation both in vitro and in vivo. Overall, these results show that chemical cues enhance the microtopographical sensitivity of cells.

Snail Augments Nuclear Deformability to Promote Lymph Node Metastasis of Head and Neck Squamous Cell Carcinoma

Up to 50% of head and neck squamous cell carcinoma (HNSCC) patients have lymph node (LN) metastasis, resulting in poor survival rate. Numerous studies have supported the notion that the alterations of gene expression and mechanical properties of cancer cells play an important role in cancer metastasis. However, which genes and how they regulate the biomechanical properties of HNSCC cells to promote LN metastasis remains elusive. In this study, we used an LN-metastatic mouse model in vivo to generate an LN-metastatic head and neck squamous cell carcinoma cell line and compared the differences in the biomolecular and biomechanical properties of LN-metastatic and non-metastatic cells. Our results showed that LN-metastatic cells had a higher level of Snail expression compared to non-LN-metastatic cells. The higher Snail expression promoted the cellular invasion capability in confined environments, mainly by increasing the longitudinal strain of the cell nuclei, which could be attributed to the stronger cell traction force and softer nuclear stiffness. These two biomechanical changes were correlated, respectively, to a larger amount of focal adhesion and less amount of nuclear lamins. Taken together, our works revealed not only the biomechanical profiles of LN-metastatic cells but also the corresponding biomolecular expressions to pinpoint the key process in LN metastasis.

Identification of hub genes and construction of an mRNA-miRNA-lncRNA network of gastric carcinoma using integrated bioinformatics analysis

Background

Gastric carcinoma (GC) is one of the most common cancer globally. Despite its worldwide decline in incidence and mortality over the past decades, gastric cancer still has a poor prognosis. However, the key regulators driving this process and their exact mechanisms have not been thoroughly studied. This study aimed to identify hub genes to improve the prognostic prediction of GC and construct a messenger RNA-microRNA-long non-coding RNA(mRNA-miRNA-lncRNA) regulatory network.

Methods

The GSE66229 dataset, from the Gene Expression Omnibus (GEO) database, and The Cancer Genome Atlas (TCGA) database were used for the bioinformatic analysis. Differential gene expression analysis methods and Weighted Gene Co-expression Network Analysis (WGCNA) were used to identify a common set of differentially co-expressed genes in GC. The genes were validated using samples from TCGA database and further validation using the online tools GEPIA database and Kaplan-Meier(KM) plotter database. Gene set enrichment analysis(GSEA) was used to identify hub genes related to signaling pathways in GC. The RNAInter database and Cytoscape software were used to construct an mRNA-miRNA-lncRNA network.

Results

A total of 12 genes were identified as the common set of differentially co-expressed genes in GC. After verification of these genes, 3 hub genes, namely CTHRC1, FNDC1, and INHBA, were found to be upregulated in tumor and associated with poor GC patient survival. In addition, an mRNA-miRNA-lncRNA regulatory network was established, which included 12 lncRNAs, 5 miRNAs, and the 3 hub genes.

Conclusions

In summary, the identification of these hub genes and the establishment of the mRNA-miRNA-lncRNA regulatory network provide new insights into the underlying mechanisms of gastric carcinogenesis. In addition, the identified hub genes, CTHRC1, FNDC1, and INHBA, may serve as novel prognostic biomarkers and therapeutic targets.

Acetylenic Synthetic Betulin Derivatives Inhibit Akt and Erk Kinases Activity, Trigger Apoptosis and Suppress Proliferation of Neuroblastoma and Rhabdomyosarcoma Cell Lines

Neuroblastoma (NB) and rhabdomyosarcoma (RMS), the most common pediatric extracranial solid tumors, still represent an important clinical challenge since no effective treatment is available for metastatic and recurrent disease. Hence, there is an urgent need for the development of new chemotherapeutics to improve the outcome of patients. Betulin (Bet), a triterpenoid from the bark of birches, demonstrated interesting anti-cancer potential. The modification of natural phytochemicals with evidenced anti-tumor activity, including Bet, is one of the methods of receiving new compounds for potential implementation in oncological treatment. Here, we showed that two acetylenic synthetic Bet derivatives (ASBDs), EB5 and EB25/1, reduced the viability and proliferation of SK-N-AS and TE671 cells, as measured by MTT and BrdU tests, respectively. Moreover, ASBDs were also more cytotoxic than temozolomide (TMZ) and cisplatin (cis-diaminedichloroplatinum [II], CDDP) in vitro, and the combination of EB5 with CDDP enhanced anti-cancer effects. We also showed the slowdown of cell cycle progression at S/G2 phases mediated by EB5 using FACS flow cytometry. The decreased viability and proliferation of pediatric cancers cells after treatment with ASBDs was linked to the reduced activity of kinases Akt, Erk1/2 and p38 and the induction of apoptosis, as investigated using Western blotting and FACS. In addition, in silico analyses of the ADMET profile found EB5 to be a promising anti-cancer drug candidate that would benefit from further investigation.

Revealing dynamic regulations and the related key proteins of myeloma-initiating cells by integrating experimental data into a systems biological model

MOTIVATION

The growth and survival of myeloma cells are greatly affected by their surrounding microenvironment. To understand the molecular mechanism and the impact of stiffness on the fate of myeloma-initiating cells (MICs), we develop a systems biological model to reveal the dynamic regulations by integrating reverse-phase protein array data and the stiffness-associated pathway.

RESULTS

We not only develop a stiffness-associated signaling pathway to describe the dynamic regulations of the MICs, but also clearly identify three critical proteins governing the MIC proliferation and death, including FAK, mTORC1 and NFκB, which are validated to be related with multiple myeloma by our immunohistochemistry experiment, computation and manually reviewed evidences. Moreover, we demonstrate that the systematic model performs better than widely used parameter estimation algorithms for the complicated signaling pathway.

AVAILABILITY AND IMPLEMENTATION

We can not only use the systems biological model to infer the stiffness-associated genetic signaling pathway and locate the critical proteins, but also investigate the important pathways, proteins or genes for other type of the cancer. Thus, it holds universal scientific significance.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Dynamic Stromal Alterations Influence Tumor-Stroma Crosstalk to Promote Pancreatic Cancer and Treatment Resistance

Many cancer studies now recognize that disease initiation, progression, and response to treatment are strongly influenced by the microenvironmental niche. Widespread desmoplasia, or fibrosis, is fundamental to pancreatic cancer development, growth, metastasis, and treatment resistance. This fibrotic landscape is largely regulated by cancer-associated fibroblasts (CAFs), which deposit and remodel extracellular matrix (ECM) in the tumor microenvironment (TME). This review will explore the prognostic and functional value of the stromal compartment in predicting outcomes and clinical prognosis in pancreatic ductal adenocarcinoma (PDAC). We will also discuss the major dynamic stromal alterations that occur in the pancreatic TME during tumor development and progression, and how the stromal ECM can influence cancer cell phenotype, metabolism, and immune response from a biochemical and biomechanical viewpoint. Lastly, we will provide an outlook on the latest clinical advances in the field of anti-fibrotic co-targeting in combination with chemotherapy or immunotherapy in PDAC, providing insight into the current challenges in treating this highly aggressive, fibrotic malignancy.

Biomimetic 3D bacterial cellulose-graphene foam hybrid scaffold regulates neural stem cell proliferation and differentiation

Neural stem cell (NSC)-based therapy is a promising candidate for treating neurodegenerative diseases and the preclinical researches call an urgent need for regulating the growth and differentiation of such cells. The recognition that three-dimensional culture has the potential to be a biologically significant system has stimulated an extraordinary impetus for scientific researches in tissue engineering and regenerative medicine. Here, A novel scaffold for culturing NSCs, three-dimensional bacterial cellulose-graphene foam (3D-BC/G), which was prepared via in situ bacterial cellulose interfacial polymerization on the skeleton surface of porous graphene foam has been reported. 3D-BC/G not only supports NSC growth and adhesion, but also maintains NSC stemness and enhances their proliferative capacity. Further phenotypic analysis indicated that 3D-BC/G induces NSCs to selectively differentiate into neurons, forming a neural network in a short amount of time. The scaffold has good biocompatibility with primary cortical neurons enhancing the neuronal network activities. To explore the underlying mechanisms, RNA-Seq analysis to identify genes and signaling pathways was performed and it suggests that 3D-BC/G offers a more promising three-dimensional conductive substrate for NSC research and neural tissue engineering, and the repertoire of gene expression serves as a basis for further studies to better understand NSC biology.

Cell Type-Specific Adhesion and Migration on Laser-Structured Opaque Surfaces

Cytocompatibility is essential for implant approval. However, initial in vitro screenings mainly include the quantity of adherent immortalized cells and cytotoxicity. Other vital parameters, such as cell migration and an in-depth understanding of the interaction between native tissue cells and implant surfaces, are rarely considered. We investigated different laser-fabricated spike structures using primary and immortalized cell lines of fibroblasts and osteoblasts and included quantification of the cell area, aspect ratio, and focal adhesions. Furthermore, we examined the three-dimensional cell interactions with spike topographies and developed a tailored migration assay for long-term monitoring on opaque materials. While fibroblasts and osteoblasts on small spikes retained their normal morphology, cells on medium and large spikes sank into the structures, affecting the composition of the cytoskeleton and thereby changing cell shape. Up to 14 days, migration appeared stronger on small spikes, probably as a consequence of adequate focal adhesion formation and an intact cytoskeleton, whereas human primary cells revealed differences in comparison to immortalized cell lines. The use of primary cells, analysis of the cell-implant structure interaction as well as cell migration might strengthen the evaluation of cytocompatibility and thereby improve the validity regarding the putative in vivo performance of implant material.

High expression of AMAP1, an ARF6 effector, is associated with elevated levels of PD-L1 and fibrosis of pancreatic cancer

BACKGROUND

Not merely the onset of immune evasion, but other factors, such as acidosis and fibrosis, are also major barriers in cancer therapeutics. Dense fibrosis is a hallmark of pancreatic ductal carcinoma (PDAC), in which hyperactivation of focal adhesion kinase (FAK) in tumor cells was shown to be crucial. Double mutations of KRAS/ TP53 are characteristic to PDAC. We previously showed that high protein expression of ARF6 and its downstream effector AMAP1, as well as processes involved in the ARF6 activation by cell surface tyrosine kinase receptors, are major targets of the KRAS/TP53 mutations to promote PDAC invasion, metastasis, and immune evasion. This notion was recaptured by KPC mouse model of human PDAC (LSL-Kras(G12D/+); LSL-Trp53(R172H/+)); Pdx-1-Cre). Mechanistically, the ARF6-AMAP1 pathway is primarily involved in cellular dynamics of PD-L1, β1-integrins, and E-cadherin; and hence modulates cell-adhesion properties when ARF6 is activated. Here, with an aim to understand whether the ARF6-AMAP1 pathway is critically involved in the elevated levels of PD-L1 and fibrosis of PDAC, we analyzed relationship between AMAP1 and these malignant phenotypes. Moreover, because the ARF6 pathway may closely be related to focal adhesion dynamics and hence to FAK, we also investigated whether AMAP1 employs FAK in fibrosis.

METHODS

Clinical specimens, as well as KPC cells/tumors and their shAMAP1 or shFAK derivatives were analyzed.

RESULTS

Elevated levels of PD-L1 and fibrosis correlated with poor outcome of our patient cohort, to be consistent with previous reports; in which high AMAP1 expression statistically correlated with the elevated PD-L1 and fibrosis. To be consistent, silencing of AMAP1 (shAMAP1) in KPC cells resulted in reduced PD-L1 expression and fibrosis in their tumors. On the other hand, shAMAP1 only slightly affected FAK activation in KPC cells, and phosphorylated FAK did not correlate with enhanced fibrosis or with poor outcome of our patients.

CONCLUSIONS

Together with our previous data, our results collectively indicated that the ARF6-AMAP1 pathway, empowered by the KRAS/TP53 mutations, is closely associated with elevated PD-L1 expression and fibrosis of human PDACs, to be recaptured in the KPC mouse model. The ARF6 pathway may promote fibrosis independent of FAK. Video abstract.

FAK regulates dynein localisation and cell polarity in migrating mouse fibroblasts

BACKGROUND

Fibroblasts executing directional migration position their centrosome, and their Golgi apparatus, in front of the nucleus towards the cell leading edge. Centrosome positioning relative to the nucleus has been associated to mechanical forces exerted on the centrosome by the microtubule-dependent molecular motor cytoplasmic dynein 1, and to nuclear movements such as rearward displacement and rotation events. Dynein has been proposed to regulate the position of the centrosome by exerting pulling forces on microtubules from the cell leading edge, where the motor is enriched during migration. However, the mechanism explaining how dynein acts at the front of the cells has not been elucidated.

RESULTS

We present here results showing that the protein Focal Adhesion Kinase (FAK) interacts with dynein and regulates the enrichment of the dynein/dynactin complex at focal adhesions at the cell the leading edge of migrating fibroblasts. This suggests that focal adhesions provide anchoring sites for dynein during the polarisation process. In support of this, we present evidence indicating that the interaction between FAK and dynein, which is regulated by the phosphorylation of FAK on its Ser732 residue, is required for proper centrosome positioning. Our results further show that the polarisation of the centrosome can occur independently of nuclear movements. Although FAK regulates both nuclear and centrosome motilities, downregulating the interaction between FAK and dynein affects only the nuclear independent polarisation of the centrosome.

CONCLUSIONS

Our work highlights the role of FAK as a key player in the regulation of several aspects of cell polarity. We thus propose a model in which the transient localisation of dynein with focal adhesions provides a tuneable mechanism to bias dynein traction forces on microtubules allowing proper centrosome positioning in front of the nucleus.

SIGNIFICANCE

We unravel here a new role for the cancer therapeutic target FAK in the regulation of cell morphogenesis.

Transcriptome Profiling Reveals Matrisome Alteration as a Key Feature of Ovarian Cancer Progression

BACKGROUND

Ovarian cancer is the most lethal gynecologic malignancy. There is a lack of comprehensive investigation of disease initiation and progression, including gene expression changes during early metastatic colonization.

METHODS

RNA-sequencing (RNA-seq) was done with matched primary tumors and fallopian tubes (n = 8 pairs) as well as matched metastatic and primary tumors (n = 11 pairs) from ovarian cancer patients. Since these are end point analyses, it was combined with RNA-seq using high-grade serous ovarian cancer cells seeded on an organotypic three-dimensional (3D) culture model of the omentum, mimicking early metastasis. This comprehensive approach revealed key changes in gene expression occurring in ovarian cancer initiation and metastasis, including early metastatic colonization.

RESULTS

2987 genes were significantly deregulated in primary tumors compared to fallopian tubes, 845 genes were differentially expressed in metastasis compared to primary tumors and 304 genes were common to both. An assessment of patient metastasis and 3D omental culture model of early metastatic colonization revealed 144 common genes that were altered during early colonization and remain deregulated even in the fully developed metastasis. Deregulation of the matrisome was a key process in early and late metastasis.

CONCLUSION

These findings will help in understanding the key pathways involved in ovarian cancer progression and eventually targeting those pathways for therapeutic interventions.

Media composition modulates human embryonic stem cell morphology and may influence preferential lineage differentiation potential

Undifferentiated human embryonic stem cells have a distinct morphology (hESC). Changes in cell morphology during culture can be indicative of differentiation. hESC, maintained in diverse medias, demonstrated alterations in morphological parameters and subsequent alterations in underlying transcript expression and lineage differentiation. Analysis of morphological parameters showed distinct and significant differences between the undefined, less defined and Xeno-free medias while still maintaining pluripotency markers. This suggested that the less defined media may be creating dynamic instability in the cytoskeleton, with the cytoskeleton becoming more stabilised in the Xeno-free media as demonstrated by smaller and rounder cells. Examination of early lineage markers during undirected differentiation using d5 embryoid bodies demonstrated increased mesodermal lineage preference as compared to endodermal or ectoderm in cells originally cultured in Xeno-free media. Undefined media showed preference for mesoderm and ectoderm lineages, while less defined media (BSA present) demonstrated no preference. These data reveal that culture media may produce fundamental changes in cell morphology which are reflected in early lineage differentiation choice.

The relationship between substrate topography and stem cell differentiation in the musculoskeletal system

It is well known that biomaterial topography can exert a profound influence on various cellular functions such as migration, polarization, and adhesion. With the development and refinement of manufacturing technology, much research has recently been focused on substrate topography-induced cell differentiation, particularly in the field of tissue engineering. Even without biological and chemical stimuli, the differentiation of stem cells can also be initiated by various biomaterials with different topographic features. However, the underlying mechanisms of this biological phenomenon remain elusive. During the past few decades, many researchers have demonstrated that cells can sense the topography of materials through the assembly and polymerization of membrane proteins. Following the activation of RHO, TGF-b or FAK signaling pathways, cells can be induced into various differentiation states. But these signaling pathways often coincide with canonical mechanical transduction pathways, and no firm conclusion has been reached among researchers in this field on topography-specific signaling pathways. On the other hand, some substrate topographies are reported to have the ability to inhibit differentiation and maintain the 'stemness' of stem cells. In this review, we will summarize the role of topography in musculoskeletal system regeneration and explore possible topography-related signaling pathways involved in cell differentiation.

Matrix stiffness regulates vascular integrity through focal adhesion kinase activity

Tumor vasculature is known to be more permeable than the vasculature found in healthy tissue, which in turn can lead to a more aggressive tumor phenotype and impair drug delivery into tumors. While the stiffening of the stroma surrounding solid tumors has been reported to increase vascular permeability, the mechanism of this process remains unclear. Here, we utilize an in vitro model of tumor stiffening, ex ovo culture, and a mouse model to investigate the molecular mechanism by which matrix stiffening alters endothelial barrier function. Our data indicate that the increased endothelial permeability caused by heightened matrix stiffness can be prevented by pharmaceutical inhibition of focal adhesion kinase (FAK) both in vitro and ex ovo. Matrix stiffness-mediated FAK activation determines Src localization to cell-cell junctions, which then induces increased vascular endothelial cadherin phosphorylation both in vitro and in vivo. Endothelial cells in stiff tumors have more activated Src and higher levels of phosphorylated vascular endothelial cadherin at adherens junctions compared to endothelial cells in more compliant tumors. Altogether, our data indicate that matrix stiffness regulates endothelial barrier integrity through FAK activity, providing one mechanism by which extracellular matrix stiffness regulates endothelial barrier function. Additionally, our work also provides further evidence that FAK is a promising potential target for cancer therapy because FAK plays a critical role in the regulation of endothelial barrier integrity.-Wang, W., Lollis, E. M., Bordeleau, F., Reinhart-King, C. A. Matrix stiffness regulates vascular integrity through focal adhesion kinase activity.

Retrospective investigation of the prognostic value of the β1 integrin expression in patients with head and neck squamous cell carcinoma receiving primary radio(chemo)therapy

This retrospective study evaluated the expression of β1 integrins and associated proteins as prognostic markers for primary radio(chemo)therapy outcome of patients with locally advanced head and neck squamous cell carcinomas (HNSCC). Tissue microarrays were prepared from 224 HNSCC patients undergoing curative primary radio(chemo)therapy from 1996 to 2005. Staining intensities of β1 integrin and its downstream-proteins FAK, phosphorylated FAK as well as the β1 integrin ECM ligands fibronectin and collagen type-I were determined. Their association to the primary endpoint loco-regional control and the secondary endpoints overall survival and freedom from distant metastasis was analyzed by Cox regression. None of the considered molecular parameters showed a significant association with loco-regional control and freedom from distant metastasis. Patients with p16 positive tumors or tumors with a low intensity of fibronectin showed significantly higher overall survival in univariable regression. In multivariable regression including additional clinical parameters, however, these parameters were not significantly associated with overall survival. Our study in a HNSCC patient cohort treated with primary radio(chemo)therapy does not reveal a prognostic value of β1 integrin expression.

DCUN1D1 facilitates tumor metastasis by activating FAK signaling and up-regulates PD-L1 in non-small-cell lung cancer

E3 ubiquitin ligases, which are key enzymes in the ubiquitin proteasome system, catalyze the ubiquitination of proteins to target them for proteasomal degradation. Emerging evidence suggests that E3 ubiquitin ligases play important roles in the development and progression of lung cancer. In our study, we characterized the gene expression landscape of lung cancer using data obtained from TCGA to explore the changes in E3 ubiquitin ligase containing the regulators of E3 ubiquitin ligase activity. Overall, most gene expression changes occurred in NSCLC tissues compared with adjacent normal ones. In total, 48 E3 ubiquitin ligases containing the regulators were up-regulated in NSCLC tissues compared with their levels in normal tissues. We analyzed the expression of up-regulated E3 ubiquitin ligases containing the regulators in two publicly available transcriptome data sets (GSE13213 and GSE30219). We found that four E3 ubiquitin ligases (UHRF1, BRCA1, TRAIP and HLTF) and one regulator of ubiquitin E3 activity DCUN1D1 that were dramatically up-regulated in cancer were significantly associated with tumor metastasis and patient's poor prognosis both in two transcriptome data sets. Next, clinical analysis indicated that the expression levels of DCUN1D1 correlated with clinical stage and lymph node metastasis in NSCLC patients as determined by quantitative reverse transcription-PCR. Furthermore, functional assays showed that DCUN1D1 promoted NSCLC cell invasion and migration as determined by transwell assay in vitro. Mechanistically, we found that the C-terminal Cullin binding domain leads to oncogenic activity and the UBA domain acts as a negative regulator of DCUN1D1 function in NSCLC. Moreover, DCUN1D1 activated the FAK oncogenic signaling pathway and up-regulated PD-L1. Taken together, our results demonstrate that DCUN1D1 is a metastasis regulator and suggest a new therapeutic option for NSCLC metastasis.

Focal Adhesion Kinase and ROCK Signaling Are Switch-Like Regulators of Human Adipose Stem Cell Differentiation towards Osteogenic and Adipogenic Lineages

Adipose tissue is an attractive stem cell source for soft and bone tissue engineering applications and stem cell therapies. The adipose-derived stromal/stem cells (ASCs) have a multilineage differentiation capacity that is regulated through extracellular signals. The cellular events related to cell adhesion and cytoskeleton have been suggested as central regulators of differentiation fate decision. However, the detailed knowledge of these molecular mechanisms in human ASCs remains limited. This study examined the significance of focal adhesion kinase (FAK), Rho-Rho-associated protein kinase (Rho-ROCK), and their downstream target extracellular signal-regulated kinase 1/2 (ERK1/2) on hASCs differentiation towards osteoblasts and adipocytes. Analyses of osteogenic markers RUNX2A, alkaline phosphatase, and matrix mineralization revealed an essential role of active FAK, ROCK, and ERK1/2 signaling for the osteogenesis of hASCs. Inhibition of these kinases with specific small molecule inhibitors diminished osteogenesis, while inhibition of FAK and ROCK activity led to elevation of adipogenic marker genes AP2 and LEP and lipid accumulation implicating adipogenesis. This denotes to a switch-like function of FAK and ROCK signaling in the osteogenic and adipogenic fates of hASCs. On the contrary, inhibition of ERK1/2 kinase activity deceased adipogenic differentiation, indicating that activation of ERK signaling is required for both adipogenic and osteogenic potential. Our findings highlight the reciprocal role of cell adhesion mechanisms and actin dynamics in regulation of hASC lineage commitment. This study enhances the knowledge of molecular mechanisms dictating hASC differentiation and thus opens possibilities for more efficient control of hASC differentiation.

Directly observing alterations of morphology and mechanical properties of living cancer cells with atomic force microscopy

Epithelial-mesenchymal transition (EMT) is a biological process during which cells lose their characteristic structure and biochemical properties then adopt typical features of a mesenchymal phenotype. Alterations in the morphology, structure, and mechanical properties of cells during EMT are associated with a series of pathological processes. In this work, atomic force microscopy (AFM) is used for investigating effects of TGF-β1 on morphology and mechanical properties of living bladder cancer cells (T24) during EMT for the first time. High-resolution topography and Young's modulus images of T24 living cell are obtained simultaneously. The results show that TGF-β1 is able to induce EMT, leading to the increased F-actin stress fibers and much higher Young's modulus values of T24 living cells. It reveals that the cytoskeletal-associated cell architecture is closely related to the mechanical dynamics of T24 cells during EMT. This work provides new insights into the changes of cell morphology and mechanical properties during EMT. It enables us to gain a deeper understanding of the growth, development and metastasis of the bladder cancer cell therefore it is of great significance for studying the pathological mechanism of cells at single-cell level.

TGFβ, Fibronectin and Integrin α5β1 Promote Invasion in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most frequent human cancer and is becoming an important health problem in an aging population. Based on their clinical and histological characteristics, thick BCC are typically divided into low-risk nodular and high-risk infiltrative subtypes, although the underlying mechanisms are poorly understood. We have identified molecular mechanisms that explain the aggressiveness of high-risk infiltrative BCC, with a potential direct clinical impact. In this study, we first show that fibroblasts, transforming growth factor-β, and fibronectin are found preferentially in infiltrative human BCC. This allowed us to develop in vivo models for the study of infiltrative BCC, which in turn let us confirm the role of transforming growth factor-β in inducing peritumoral fibronectin deposition and tumor infiltration. We then show that fibronectin promotes adhesion and migration of BCC cell lines through integrin α5β1-mediated phosphorylation of focal adhesion kinase. Fittingly, both inhibition of integrin α5β1 and phospho-focal adhesion kinase prevent fibronectin-induced migration of BCC cells in vitro as well as BCC infiltration in vivo. Altogether, our results open important insights into the pathogenesis of aggressive infiltrative BCC and identify integrin α5β1 or focal adhesion kinase inhibition as promising strategies for the treatment of advanced BCC.

Focal adhesion kinase (FAK) deficiency in mononuclear phagocytes alters murine breast tumor progression

While it has long been recognized that mononuclear phagocytes play a significant role in determining breast tumor progression, the molecular factors that contribute to these events are not fully understood. In this report, we sought to determine whether focal adhesion kinase (FAK) expression in this cell population influences primary breast tumor initiation and growth. Using the MMTV-polyoma middle T (PyVmT) murine model of spontaneous breast cancer, we found that FAK expression in mononuclear phagocytes accelerates tumor initiation/progression during the early stages of PyVmT tumor growth but subsequently restricts tumor growth once the tumors have transitioned to malignancy. Mononuclear phagocytes accumulated at the site of developing tumors in a FAK-independent manner. However, once in the tumor, our data suggest that FAK expression is upregulated in the tumor-associated myeloid cells, and its activity in this population of cells may influence the immune landscape of the tumor by supporting the recruitment and/or survival of NK cells. Together, these data support a model in which FAK expression in the mononuclear phagocyte compartment positively regulates the early steps of tumor progression but subsequently functions to restrict tumor growth as the tumors transition to invasive carcinoma.

Cancer Cell Mechanics: Adhesion G Protein-coupled Receptors in Action?

In mammals, numerous organ systems are equipped with adhesion G protein-coupled receptors (aGPCRs) to shape cellular processes including migration, adhesion, polarity and guidance. All of these cell biological aspects are closely associated with tumor cell biology. Consistently, aberrant expression or malfunction of aGPCRs has been associated with dysplasia and tumorigenesis. Mounting evidence indicates that cancer cells comprise viscoelastic properties that are different from that of their non-tumorigenic counterparts, a feature that is believed to contribute to the increased motility and invasiveness of metastatic cancer cells. This is particularly interesting in light of the recent identification of the mechanosensitive facility of aGPCRs. aGPCRs are signified by large extracellular domains (ECDs) with adhesive properties, which promote the engagement with insoluble ligands. This configuration may enable reliable force transmission to the ECDs and may constitute a molecular switch, vital for mechano-dependent aGPCR signaling. The investigation of aGPCR function in mechanosensation is still in its infancy and has been largely restricted to physiological contexts. It remains to be elucidated if and how aGPCR function affects the mechanoregulation of tumor cells, how this may shape the mechanical signature and ultimately determines the pathological features of a cancer cell. This article aims to view known aGPCR functions from a biomechanical perspective and to delineate how this might impinge on the mechanobiology of cancer cells.

Expression of DCUN1D1 in laryngeal squamous cell carcinoma and its inhibiting effect on TU-177 cells after interfered by RNA

Expression of DCUN1D1 in laryngeal squamous cell carcinoma (LSCC) and its inhibition by small interfering RNA (siRNA) target in the TU-177 cells was investigated. Immunohistochemistry was used to detect the expression level of DCUN1D1 in LSCC tissue in 140 cases and to analyze its relationship with clinical pathological characteristics. siRNA expression plasmid targeting DCUN1D1 was constructed and transferred into TU-177 cells. The effect of siRNA target DCUN1D1 gene silencing on proliferation, invasion and migration of TU-177 cells were observed by MTS assay and Transwell experiment. The expression levels of focal adhesion kinase (FAK) and matrix metalloproteinase-2(MMP-2) were detected by western blot. Expression level of DCUN1D1 protein increased significantly in T3 + T4, N+, and III + IV stages of LSCC patients (P < .05). After DCUN1D1 was targeted by siRNA, the DCUN1D1 protein level decreased 67% in siRNA-3 group, where average absorbance value was lower than the control and blank group with significant difference(F = 6.076, P < .05) in MTS assay, meantime migration, and invasion cells in each vision were the same (F = 19.851, F = 25.454, P < .01) in the Transwell experiment. The expression level of FAK and MMP-2 was significantly down-regulated in siRNA-3 group (F = 28.896, F = 40.240, P < .01). DCUN1D1 is associated with progression and prognosis of LSCC. After siRNA based target on DCUN1D1, TU-177 cells growth was inhibited and invasion of malignant tumour was diminished by reducing the expression of FAK and MMP-2. DCUN1D1 is could become a potential new target for the treatment of LSCC.

Curved microstructures promote osteogenesis of mesenchymal stem cells via the RhoA/ROCK pathway

OBJECTIVES

Cells in the osteon reside in a curved space, accordingly, the curvature of the microenvironment is an important geometric feature in bone formation. However, it is not clear how curved microstructures affect cellular behaviour in bone tissue.

MATERIALS AND METHODS

Rat primary bone marrow mesenchymal stem cells (BMSCs) on wavy microgrooves were exposed to PDMS substrates with various curvatures to investigate alterations in cellular morphology and osteogenic differentiation. Additionally, the expression levels of RhoA and its effectors were examined by immunofluorescence and quantitative PCR to determine the mechanisms of curvature-dependent osteogenic differentiation.

RESULTS

Wavy microgrooves caused dramatic nuclear distortion and cytoskeletal remodelling. We detected a noticeable increase in the expression of osteogenic-related genes in BMSCs in wavy microgroove groups, and the maximum expression was observed in the high curvature group. Moreover, immunofluorescent staining and quantitative RT-PCR results for RhoA and its effectors showed that the RhoA/ROCK signalling pathway is associated with curvature-dependent osteogenic differentiation.

CONCLUSIONS

Our results illustrated that curved microstructures could promote BMSC differentiation to the osteogenic lineage, and the osteogenic effects of higher curvature are more obvious. Wavy microstructures could also influence the RhoA/ROCK pathway. Accordingly, curved microstructures may be useful in bone tissue engineering.

Live-single-cell phenotypic cancer biomarkers-future role in precision oncology?

The promise of precision and personalized medicine is rooted in accurate, highly sensitive, and specific disease biomarkers. This is particularly true for cancer-a disease characterized by marked tumor heterogeneity and diverse molecular signatures. Although thousands of biomarkers have been described, only a very small number have been successfully translated into clinical use. Undoubtedly, there is need for rapid, quantitative, and more cost effective biomarkers for tumor diagnosis and prognosis, to allow for better risk stratification and aid clinicians in making personalized treatment decisions. This is particularly true for cancers where specific biomarkers are either not available (e.g., renal cell carcinoma) or where current biomarkers tend to classify individuals into broad risk categories unable to accurately assess individual tumor aggressiveness and adverse pathology potential (e.g., prostate cancer), thereby leading to problems of over-diagnosis and over-treatment of indolent cancer and under-treatment of aggressive cancer. This perspective highlights an emerging class of cancer biomarkers-live-single-cell phenotypic biomarkers, as compared to genomic biomarkers, and their potential application for cancer diagnosis, risk-stratification, and prognosis.

Tumor protein D52 (isoform 3) contributes to prostate cancer cell growth via targeting nuclear factor-κB transactivation in LNCaP cells

Our previous study showed that TPD52 overexpression could increase migration and proliferation of LNCaP cells contributing to the development of prostate cancer. However, mechanism of TPD52 in prostate cancer initiation and progression remains elusive. In this study, we investigated the possible underlying mechanism of TPD52 in prostate cancer progression. In LNCaP cells, TPD52 expression was altered by transfecting with either EGFP-TPD52 or specific short hairpin RNA. Overexpression of TPD52 protected LNCaP cells from apoptosis through elevated anti-apoptotic proteins XIAP, Bcl-2, and Cyclin D1, whereas Bax was downregulated. Mechanistically, we found that TPD52 confers transactivation of nuclear factor-κB, thereby enhancing its target gene expression in LNCaP cells. TPD52 promotes LNCaP cell invasion probably via increased matrix metalloproteinase 9 expression and its activity while tissue inhibitor of metalloproteinase expression is significantly downregulated. Notably, TPD52 might be involved in cell adhesion, promoting tumor metastasis by inducing loss of E-cadherin, expression of vimentin and vascular cell adhesion molecule, and additionally activation of focal adhesion kinase. Furthermore, TPD52 directly interacts with nuclear factor-κB p65 (RelA) and promotes accumulation of phosphorylated nuclear factor-κB (p65)^S536 that is directly linked with nuclear factor-κB transactivation. Indeed, depletion of TPD52 or inhibition of nuclear factor-κB in TPD52-positive cells inhibited secretion of tumor-related cytokines and contributes to the activation of STAT3, nuclear factor-κB, and Akt. Interestingly, in TPD52 overexpressing LNCaP cells, nuclear factor-κB inhibition prevented the autocrine/paracrine activation of STAT3. TPD52 activates STAT3 through ascertaining a cross talk between the nuclear factor-κB and the STAT3 signaling systems. Collectively, these results reveal mechanism by which TPD52 is associated with prostate cancer progression and highlight the approach for therapeutic targeting of TPD52 in prostate cancer.

Focal Adhesion Kinase: The Reversible Molecular Mechanosensor

Sensors are the first element of the pathways that control the response of cells to their environment. Protein complexes that produce or enable a chemical signal in response to a mechanical stimulus are called "mechanosensors". In this work, we develop a theoretical model describing the physical mechanism of a reversible single-molecule stiffness sensor. Although this has the potential for general application, here we apply the model to focal adhesion kinase, which initiates the chemical signal in its active phosphorylated conformation, but can spontaneously return to its closed folded conformation. We find how the rates of conformation changes depend on the substrate stiffness and the pulling force applied from the cell cytoskeleton. We find the sensor is homeostatic, spontaneously self-adjusting to reach a state where its range of maximum sensitivity matches the substrate stiffness. The results compare well with the phenotype observations of cells on different substrates.

Dentin sialoprotein facilitates dental mesenchymal cell differentiation and dentin formation

Dentin sialoprotein (DSP) is a dentin extracellular matrix protein. It is involved in dental mesenchymal cell lineages and dentin formation through regulation of its target gene expression. DSP mutations cause dentin genetic diseases. However, mechanisms of DSP in controlling dental mesenchymal cell differentiation are unknown. Using DSP as bait, we screened a protein library from mouse odontoblastic cells and found that DSP is a ligand and binds to cell surface receptor, occludin. Further study identified that the C-terminal DSP domain^{aa 363–458} interacts with the occludin extracellular loop 2^{aa 194–241}. The C-terminal DSP domain induced phosphorylation of occludin Ser⁴⁹⁰ and focal adhesion kinase (FAK) Ser⁷²² and Tyr⁵⁷⁶. Coexpression of DSP, occludin and FAK was detected in dental mesenchymal cells during tooth development. Occludin physically interacts with FAK, and occludin and FAK phosphorylation can be blocked by DSP and occludin antibodies. This DSP domain facilitates dental mesenchymal cell differentiation and mineralization. Furthermore, transplantation and pulp-capping procedures revealed that this DSP domain induces endogenous dental pulp mesenchymal cell proliferation, differentiation and migration, while stimulating blood vessel proliferation. This study elucidates the mechanism of DSP in dental mesenchymal lineages and implies that DSP may serve as a therapeutic agent for dentin-pulp complex regeneration in dental caries.

Osteoblast and stem cell response to nanoscale topographies: a review

To understand how cells respond to the nanoscale extracellular environment in vivo, cells from various sources have been cultured on nanoscale patterns fabricated using bottom-up and top-down techniques. Human fetal osteoblasts (hFOBs) and stem cells are some of them and they are known to be overtly responsive to nanoscale topographies - allowing us to investigate the hows and whys of the response in vitro. Information gathered from these in vitro studies could be used to control the cells, i.e. make the stem cells differentiate or retain their characteristics without the use of medium supplements. In this review, hFOB and stem cell responses to nanotopographies are summarized and discussed to shed some light on the influence of patterns on the reactions. Although both types of cells are responsive to nanoscale topographies, the responses are found to be unique to topographical dimension, shape, orientation and the types of cells used. This implies that cellular responses are influenced by multitude of factors and that if done right, cheaper self-assembled nanotopographies can be tailored to control the cells. A new self-assembly, powder-based technique is also included to provide an insight into the future of nanofabrication.

A cytoplasmic C-terminal fragment of Syndecan-1 is generated by sequential proteolysis and antagonizes Syndecan-1 dependent lung tumor cell migration

Syndecan-1 is a surface expressed heparan sulphate proteoglycan, which is upregulated by several tumor types and involved in tumor cell migration and metastasis. Syndecan-1 is shed from the cell surface and the remaining transmembrane fragment undergoes intramembrane proteolysis by γ-secretase. We here show that this generates a cytoplasmic C-terminal fragment (cCTF). In epithelial lung tumor A549 cells the endogenously produced cCTF accumulated when its proteasomal degradation was blocked with bortezomib and this accumulation was prevented by γ-secretase inhibition. Overexpression of the cCTF suppressed migration and invasion of A549 cells. This inhibitory effect was only seen when endogenous syndecan-1 was present, but not in syndecan-1 deficient cells. Further, overexpression of syndecan-1 cCTF increased the basal activation of Src kinase, focal adhesion kinase (FAK) and Rho GTPase. This was associated with increased adhesion to fibronectin and collagen G and an increased recruitment of paxillin to focal adhesions. Moreover, lung tumor formation of A549 cells in mice was reduced by overexpression of syndecan-1 cCTF. Finally, delivery of a synthetic peptide corresponding to the syndecan-1 cCTF suppressed A549 cell migration and increased basal phosphorylation of Src and FAK. Our data indicate that the syndecan-1 cCTF antagonizes syndecan-1 dependent tumor cell migration in vitro and in vivo by dysregulating proadhesive signaling pathways and suggest that the cCTF can be used as an inhibitory peptide.

A first-in-Asian phase 1 study to evaluate safety, pharmacokinetics and clinical activity of VS-6063, a focal adhesion kinase (FAK) inhibitor in Japanese patients with advanced solid tumors

Purpose

VS-6063 (also known as defactinib or PF-04554878) is a second-generation inhibitor of focal adhesion kinase and proline-rich tyrosine kinase-2. This phase 1 study evaluated the safety and tolerability, pharmacokinetics, and clinical activity of VS-6063 in Japanese subjects with advanced solid tumor malignancies in a first-in-Asian study setting.

Methods

VS-6063 was administered orally twice daily (b.i.d.) in 21-day cycles to cohorts of three subjects each with a standard 3 + 3 dose-escalation design until disease progression or unacceptable toxicity. Blood samples for pharmacokinetics were collected on Day 1 and 15. The assessments were performed using CTCAE v4.0 for adverse events (AEs), and the Response Evaluation Criteria In Solid Tumors, version v1.1 (RECIST v1.1) for tumor response.

Results

Nine patients were treated across three dose levels (200–600 mg BID). No dose-limiting toxicities were observed at any dose level. Most frequent treatment-related AEs were Grade 1/2 unconjugated hyperbilirubinemia, fatigue, decreased appetite, and diarrhea. Only one subject in the 200 mg BID cohort experienced reversible and transient Grade 3 unconjugated hyperbilirubinemia. PK analyses confirmed that the exposure at the recommended Phase 2 dose (RP2D) of 400 mg BID was comparable with exposures previously reported in non-Japanese subjects. Durable stable disease of approximately 24 weeks was confirmed in two subjects (malignant mesothelioma and rectal cancer).

Conclusions

VS-6063 was well tolerated at all dose levels investigated in this first-in-Asian study. These data support the administration of VS-6063 to Japanese subjects at the RP2D in clinical trials involving solid tumor malignancies.