Vimentin-mediated regulation of cell motility through modulation of beta4 integrin protein levels in oral tumor derived cells

Plectin: Dual Participation in Tumor Progression

The plectin gene can encode a cytoskeletal linking protein, plectin, known for its interaction with three critical components of the cellular cytoskeleton: intermediate filaments, microtubules, and actin filaments. In recent years, more and more studies have reported that plectin is closely related to tumorigenesis and development, exhibiting both tumor-suppressive and tumor-promoting functions. Here, we first introduce the molecular structure and function of plectin, and then we summarize the current understanding of the crucial role of plectin in cancer progression. Finally, we also discuss the possible reasons for the different roles of plectin expression in various types of cancer and highlight the double-edged sword role of plectin in tumor progression. The review aims to deepen the comprehensive understanding of plectin's role in cancer and further help to develop novel therapeutic strategies and drug targets.

The mechanism of ITGB4 in tumor migration and invasion

Integrin β4 (ITGB4) is a transmembrane protein that functions as a mechanosensor, mediating the bidirectional exchange of information between the intracellular and extracellular matrices. ITGB4 plays a critical role in cell adhesion, migration, and signaling. Numerous studies have implicated ITGB4 as a key facilitator of tumor migration and invasion. This review provides a foundational description of the mechanisms by which ITGB4 regulates tumor migration and invasion through pathways involving focal adhesion kinase (FAK), protein kinase B (AKT), and matrix metalloproteinases (MMPs). These mechanisms encompass epithelial-mesenchymal transition (EMT), phosphorylation, and methylation of associated molecules. Additionally, this review explores the role of ITGB4 in the migration and invasion of prevalent clinical tumors, including those of the digestive system, breast, and prostate.

Mechanotransduction and epigenetic modulations of chromatin: Role of mechanical signals in gene regulation

Mechanical forces may be generated within a cell due to tissue stiffness, cytoskeletal reorganization, and the changes (even subtle) in the cell's physical surroundings. These changes of forces impose a mechanical tension within the intracellular protein network (both cytosolic and nuclear). Mechanical tension could be released by a series of protein-protein interactions often facilitated by membrane lipids, lectins and sugar molecules and thus generate a type of signal to drive cellular processes, including cell differentiation, polarity, growth, adhesion, movement, and survival. Recent experimental data have accentuated the molecular mechanism of this mechanical signal transduction pathway, dubbed mechanotransduction. Mechanosensitive proteins in the cell's plasma membrane discern the physical forces and channel the information to the cell interior. Cells respond to the message by altering their cytoskeletal arrangement and directly transmitting the signal to the nucleus through the connection of the cytoskeleton and nucleoskeleton before the information despatched to the nucleus by biochemical signaling pathways. Nuclear transmission of the force leads to the activation of chromatin modifiers and modulation of the epigenetic landscape, inducing chromatin reorganization and gene expression regulation; by the time chemical messengers (transcription factors) arrive into the nucleus. While significant research has been done on the role of mechanotransduction in tumor development and cancer progression/metastasis, the mechanistic basis of force-activated carcinogenesis is still enigmatic. Here, in this review, we have discussed the various cues and molecular connections to better comprehend the cellular mechanotransduction pathway, and we also explored the detailed role of some of the multiple players (proteins and macromolecular complexes) involved in mechanotransduction. Thus, we have described an avenue: how mechanical stress directs the epigenetic modifiers to modulate the epigenome of the cells and how aberrant stress leads to the cancer phenotype.

Nanostructured graphene oxide enriched with metallic nanoparticles as a biointerface to enhance cell adhesion through mechanosensory modifications

Nanostructuring is a process involving surface manipulation at the nanometric level, which improves the mechanical and biological properties of biomaterials. Specifically, it affects the mechanotransductive perception of the microenvironment of cells. Mechanical force conversion into an electrical or chemical signal contributes to the induction of a specific cellular response. The relationship between the cells and growth surface induces a biointerface-modifying cytophysiology and consequently a therapeutic effect. In this study, we present the fabrication of graphene oxide (GO)-based nanofilms decorated with metallic nanoparticles (NPs) as potential coatings for biomaterials. Our investigation showed the effect of decorating GO with metallic NPs for the modification of the physicochemical properties of nanostructures in the form of nanoflakes and nanofilms. A comprehensive biocompatibility screening panel revealed no disturbance in the metabolic activity of human fibroblasts (HFFF2) and bone marrow stroma cells (HS-5) cultivated on the GO nanofilms decorated with gold and copper NPs, whereas a significant cytotoxic effect of the GO nanocomplex decorated with silver NPs was demonstrated. The GO nanofilm decorated with gold NPs beneficially managed early cell adhesion as a result of the transient upregulation of α1β5 integrin expression, acceleration of cellspreading, and formation of elongated filopodia. Additionally, the cells, sensing the substrate derived from the nanocomplex enriched with gold NPs, showed reduced elasticity and altered levels of vimentin expression. In the future, GO nanocomplexes decorated with gold NPs can be incorporated in the structure of architecturally designed biomimetic biomaterials as biocompatible nanostructuring agents with proadhesive properties.

Role of Hemidesmosomes in Oral Carcinogenesis: A Systematic Review

BACKGROUND

Oral cancers have limited diagnostic tools to aid clinical management. Current evidence indicates that alterations in hemidesmosomes, the adhesion complexes primarily involved in epithelial attachment to the basement membrane, are correlated to cancer phenotype for multiple cancers. This systematic review aimed to assess the experimental evidence for hemidesmosomal alterations, specifically in relation to oral potentially malignant disorders and oral squamous cell carcinomas.

METHODS

We conducted a systemic review to summarise the available literature on hemidesmosomal components and their role in oral pre-cancer and cancer. Relevant studies were retrieved from a comprehensive search of Scopus, Ovid MEDLINE, Ovid Embase and Web of Science.

RESULTS

26 articles met the inclusion criteria, of which 19 were in vitro studies, 4 in vivo studies, 1 in vitro and in vivo study, and 2 in vitro and cohort studies. Among them, 15 studies discussed individual alpha-6 and/or beta-4 subunits, 12 studies discussed the alpha-6 beta-4 heterodimers, 6 studies discussed the entire hemidesmosome complex, 5 studies discussed bullous pemphigoid-180, 3 studies discussed plectin, 3 studies discussed bullous pemphigoid antigen-1 and 1 study discussed tetraspanin.

CONCLUSION

Heterogeneity in cell type, experimental models, and methods were observed. Alterations in hemidesmosomal components were shown to contribute to oral pre-cancer and cancer. We conclude that there is sufficient evidence for hemidesmosomes and their components to be potential biomarkers for evaluating oral carcinogenesis.

Investigation of electrical stimulation on phenotypic vascular smooth muscle cells differentiation in tissue-engineered small-diameter vascular graft

In the development of vascular tissue engineering, particularly in the case of small diameter vessels, one of the key obstacles is the blockage of these veins once they enter the in vivo environment. One of the contributing factors to this problem is the aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) from the media layer of the artery to the interior of the channel. Two distinct phenotypes have been identified for smooth muscle cells, namely synthetic and contractile. Since the synthetic phenotype plays an essential role in the unusual growth and migration, the aim of this study was to convert the synthetic phenotype into the contractile one, which is a solution to prevent the abnormal growth of VSMCs. To achieve this goal, these cells were subjected to electrical signals, using a 1000 μA sinusoidal stimulation at 10 Hz for four days, with 20 min duration per 24 h. The morphological transformations and changes in the expression of vimentin, nestin, and β-actin proteins were then studied using ICC and flow cytometry assays. Also, the expression of VSMC specific markers such as smooth muscle myosin heavy chain (SMMHC) and smooth muscle alpha-actin (α-SMA) were evaluated using RT-PCR test. In the final phase of this study, the sheep decellularized vessel was employed as a scaffold for seeding these cells. Based on the results, electrical stimulation resulted in some morphological alterations in VSMCs. Furthermore, the observed reductions in the expression levels of vimentin, nestin and β-actin proteins and increase in the expression of SMMHC and α-SMA markers showed that it is possible to convert the synthetic phenotype to the contractile one using the studied regime of electrical stimulation. Finally, it can be concluded that electrical stimulation can significantly affect the phenotype of VSMCs, as demonstrated in this study.

Structural mechanism for inhibition of PP2A-B56α and oncogenicity by CIP2A

The protein phosphatase 2A (PP2A) heterotrimer PP2A-B56α is a human tumour suppressor. However, the molecular mechanisms inhibiting PP2A-B56α in cancer are poorly understood. Here, we report molecular level details and structural mechanisms of PP2A-B56α inhibition by an oncoprotein CIP2A. Upon direct binding to PP2A-B56α trimer, CIP2A displaces the PP2A-A subunit and thereby hijacks both the B56α, and the catalytic PP2Ac subunit to form a CIP2A-B56α-PP2Ac pseudotrimer. Further, CIP2A competes with B56α substrate binding by blocking the LxxIxE-motif substrate binding pocket on B56α. Relevant to oncogenic activity of CIP2A across human cancers, the N-terminal head domain-mediated interaction with B56α stabilizes CIP2A protein. Functionally, CRISPR/Cas9-mediated single amino acid mutagenesis of the head domain blunted MYC expression and MEK phosphorylation, and abrogated triple-negative breast cancer in vivo tumour growth. Collectively, we discover a unique multi-step hijack and mute protein complex regulation mechanism resulting in tumour suppressor PP2A-B56α inhibition. Further, the results unfold a structural determinant for the oncogenic activity of CIP2A, potentially facilitating therapeutic modulation of CIP2A in cancer and other diseases.

Soft substrates promote direct chemical reprogramming of fibroblasts into neurons

Fibroblasts can be directly reprogrammed via a combination of small molecules to generate induced neurons (iNs), bypassing intermediate stages. This method holds great promise for regenerative medicine; however, it remains inefficient. Recently, studies have suggested that physical cues may improve the direct reprogramming of fibroblasts into neurons, but the underlying mechanisms remain to be further explored, and the physical factors reported to date do not exhibit the full properties of the extracellular matrix (ECM). Previous in vitro studies mainly used rigid polystyrene dishes, while one of the characteristics of the native in-vivo environment of neurons is the soft nature of brain ECM. The reported stiffness of brain tissue is very soft ranging between 100 Pa and 3 kPa, and the effect of substrate stiffness on direct neuronal reprogramming has not been explored. Here, we show for the first time that soft substrates substantially improved the production efficiency and quality of iNs, without needing to co-culture with glial cells during reprogramming, producing more glutamatergic neurons with electrophysiological functions in a shorter time. Transcriptome sequencing indicated that soft substrates might promote glutamatergic neuron reprogramming through integrins, actin cytoskeleton, Hippo signalling pathway, and regulation of mesenchymal-to-epithelial transition, and competing endogenous RNA network analysis provided new targets for neuronal reprogramming. We demonstrated that soft substrates may promote neuronal reprogramming by inhibiting microRNA-615-3p-targeting integrin subunit beta 4. Our findings can aid the development of regenerative therapies and help improve our understanding of neuronal reprogramming. STATEMENT OF SIGNIFICANCE: : First, we have shown that low stiffness promotes direct reprogramming on the basis of small molecule combinations. To the best of our knowledge, this is the first report on this type of method, which may greatly promote the progress of neural reprogramming. Second, we found that miR-615-3p may interact with ITGB4, and the soft substrates may promote neural reprogramming by inhibiting microRNA (miR)-615-3p targeting integrin subunit beta 4 (ITGB4). We are the first to report on this mechanism. Our findings will provide more functional neurons for subsequent basic and clinical research in neurological regenerative medicine, and will help to improve the overall understanding of neural reprogramming. This work also provides new ideas for the design of medical biomaterials for nerve regeneration.

Utility of Keratins as Biomarkers for Human Oral Precancer and Cancer

Human oral cancer is the single largest group of malignancies in the Indian subcontinent and the sixth largest group of malignancies worldwide. Squamous cell carcinomas (SCC) are the most common epithelial malignancy of the oral cavity, constituting over 90% of oral cancers. About 90% of OSCCs arise from pre-existing, potentially malignant lesions. According to WHO, OSCC has a 5-year survival rate of 45–60%. Late diagnosis, recurrence, and regional or lymph nodal metastases could be the main causes of the high mortality rates. Biomarkers may help categorize and predict premalignant lesions as high risk of developing malignancy, local recurrence, and lymph nodal metastasis. However, at present, there is a dearth of such markers, and this is an area of ongoing research. Keratins (K) or cytokeratins are a group of intermediate filament proteins that show paired and differentiation dependent expression. Our laboratory and others have shown consistent alterations in the expression patterns of keratins in both oral precancerous lesions and tumors. The correlation of these changes with clinicopathological parameters has also been demonstrated. Furthermore, the functional significance of aberrant keratins 8/18 expression in the malignant transformation and progression of oral tumors has also been documented. This article reviews the literature that emphasizes the value of keratins as biomarkers for the prognostication of human oral precancers and cancers.

Biomarker Potential of Vimentin in Oral Cancers

Oral carcinogenesis is a multistep process. As much as 5% to 85% of oral tumors can develop from potentially malignant disorders (PMD). Although the oral cavity is accessible for visual examination, the ability of current clinical or histological methods to predict the lesions that can progress to malignancy is limited. Thus, developing biological markers that will serve as an adjunct to histodiagnosis has become essential. Our previous studies comprehensively demonstrated that aberrant vimentin expression in oral premalignant lesions correlates to the degree of malignancy. Likewise, overwhelming research from various groups show a substantial contribution of vimentin in oral cancer progression. In this review, we have described studies on vimentin in oral cancers, to make a compelling case for vimentin as a prognostic biomarker.

San-Zhong-Kui-Jian-Tang Exerts Antitumor Effects Associated With Decreased Cell Proliferation and Metastasis by Targeting ERK and the Epithelial-Mesenchymal Transition Pathway in Oral Cavity Squamous Cell Carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is an aggressive cancer whose 5-year survival rate remains poor. San-Zhong-Kui-Jian-Tang (SZKJT), a Chinese herbal formula, has long been used in clinical practice as adjuvant therapy in cancers. However, its therapeutic effects and molecular mechanisms in OSCC remain unclear.

METHODS

We investigated the potential therapeutic effects and molecular mechanism of SZKJT in OSCC in tumor cell lines and in tumor xenograft mice and evaluated combined SZKJT and cisplatin treatment efficacy. In vitro-cultured OSCC cells were administered SZKJT at different doses or SZKJT plus cisplatin, and cell proliferation, colony formation assays, and cell cycle analysis were used to assess the effects on cancer cell proliferation and apoptosis. We also analyzed the effects of SZKJT on oral cancer cell line migration, the regulation of mitogen-activated protein kinase (MAPK) signaling, and epithelial-mesenchymal transition (EMT)-associated genes. The antitumor effects of SZKJT plus cisplatin were also tested in vivo using a tumor-bearing NOD/SCID mice model.

RESULTS

The results showed that SZKJT effectively inhibited OSCC cell proliferation, induced cell cycle S phase arrest, and induced cell apoptosis. SZKJT also inhibited cell migration by modulating the MAPK signaling and epithelial-mesenchymal transition (EMT) pathway. Further exploration suggested that SZKJT affects OSCC by modulating ERK pathway; downregulating vimentin, fibronectin, and Oct-4; and upregulating E-cadherin. In vivo, SZKJT significantly inhibited tumor growth, and SZKJT and cisplatin exerted synergistic antitumor effects in model animals.

CONCLUSIONS

SZKJT exerts antitumor effects in OSCC cells. Additionally, SZKJT and cisplatin exhibit synergy in OSCC treatment. These findings support the clinical usage of Chinese herbal formulas as adjuvant therapy with chemotherapy in cancer treatment.

FKBP1A upregulation correlates with poor prognosis and increased metastatic potential of HNSCC

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy globally. The etiology of HNSCC is multifactorial, including cellular stress induced by a tobacco smoking, tobacco chewing excess alcohol consumption, and human papillomavirus infection. The induction of stress includes autophagy as one of the response pathways in maintaining homeostatic equilibrium. We evaluated the expression of autophagy-related genes in HNSCC tissues from RNA sequencing datasets and identified 19 genes correlated with poor prognosis and 18 genes correlated with improved prognosis of HNSCC patients. Further analysis of independent gene expression datasets revealed that ATG12, HSP90AB1, and FKBP1A are overexpressed in HNSCC and correlate with poor prognosis, whereas the overexpression of ANXA1, FOS, and ULK3 correlates with improved prognosis. Using independent datasets, we also found that ATG12, HSP90AB1, and FKBP1A expression increased with an increase in the T-stage of HNSCC. Among all the datasets analyzed, FKBP1A was overexpressed in HNSCC and was strongly associated with lymph node metastasis in multiple in silico datasets. In conclusion, our analysis indicates dynamic alterations in autophagy genes during HNSCC and warrants further investigation, specifically on FKBP1A and its role in tumor progression and metastasis.

Plectin in Cancer: From Biomarker to Therapeutic Target

The cytolinker and scaffolding protein, plectin, has emerged as a potent driver of malignant hallmarks in many human cancers due to its involvement in various cellular activities contributing to tumorigenesis, including cancer cell proliferation, adhesion, migration, invasion, and signal transduction. Evidence shows that beyond plectin's diverse protein interactome, its cancer-specific mislocalization to the cell surface enables its function as a potent oncoprotein. As such, therapeutic targeting of plectin, its protein interactors, and, in particular, cancer-specific plectin (CSP) presents an attractive opportunity to impede carcinogenesis directly. Here, we report on plectin's differential gene and protein expression in cancer, explore its mutational profile, and discuss the current understanding of plectin's and CSP's biological function in cancer. Moreover, we review the landscape of plectin as a prognostic marker, diagnostic biomarker, and target for imaging and therapeutic modalities. We highlight how, beyond their respective biological importance, plectin's common overexpression in cancer and CSP's cancer-specific bioavailability underscore their potential as high-value druggable targets. We discuss how recent evidence of the potent anti-cancer effects of CSP therapeutic targeting opens the door for cell-surface mislocalized proteins as novel therapeutic targets.

Rac1-mediated sustained β4 integrin level develops reattachment ability of breast cancer cells after anchorage loss

Previously, we reported that non-apoptotic cell death was induced in non-malignant mammary epithelial cells (HMECs) upon loss of anchorage during 48 h incubation in suspension. In this study, we examined HMECs in suspension at an earlier time point and found that most of them lost attachment ability to substrata when replated, although >80% were alive. This suggested that HMECs lost reattachment ability (RA) prior to cell death upon detachment. Concomitant with the loss of RA, a decrease in the levels of β1 and β4 integrin was observed. In sharp contrast, breast cancer cells retained integrin levels, reattached to substrata, and formed colonies after exposure to anchorage loss as efficiently as those maintained under adherent conditions. Such RA of cancer cells is essential for the metastatic process, especially for establishing adhesion contact with ECM in the secondary organ after systemic circulation. Further analysis suggested that sustained levels of β4 integrin, which was mediated by Rac1, was critical for RA after anchorage loss and lung metastasis of breast cancer cells. In the cancer cells, persistent Rac1 activity enhanced escape of β4 integrin from lysosomal degradation depending on actin-related protein 2/3 and TBC1D2, a GTPase-activating protein of Rab7 GTPase. Notably, simultaneous high expression of ITGB4 and RAC1 was associated with poor prognosis in patients with breast cancer. Therefore, β4 integrin and Rac1 are attractive therapeutic targets to eliminate RA in cancer cells, thereby preventing the initial step of colonization at the secondary organ during metastasis.

Targeting the cytoskeleton against metastatic dissemination

Cancer is a pathology characterized by a loss or a perturbation of a number of typical features of normal cell behaviour. Indeed, the acquisition of an inappropriate migratory and invasive phenotype has been reported to be one of the hallmarks of cancer. The cytoskeleton is a complex dynamic network of highly ordered interlinking filaments playing a key role in the control of fundamental cellular processes, like cell shape maintenance, motility, division and intracellular transport. Moreover, deregulation of this complex machinery contributes to cancer progression and malignancy, enabling cells to acquire an invasive and metastatic phenotype. Metastasis accounts for 90% of death from patients affected by solid tumours, while an efficient prevention and suppression of metastatic disease still remains elusive. This results in the lack of effective therapeutic options currently available for patients with advanced disease. In this context, the cytoskeleton with its regulatory and structural proteins emerges as a novel and highly effective target to be exploited for a substantial therapeutic effort toward the development of specific anti-metastatic drugs. Here we provide an overview of the role of cytoskeleton components and interacting proteins in cancer metastasis with a special focus on small molecule compounds interfering with the actin cytoskeleton organization and function. The emerging involvement of microtubules and intermediate filaments in cancer metastasis is also reviewed.

Clinical Significance of Integrin Subunit Beta 4 in Head and Neck Squamous Cell Carcinoma

Background: The expression level and clinical significance of integrin subunit beta 4 (ITGB4) in head and neck squamous cell carcinoma (HNSCC) remain unclear. Materials and Methods: Expression of ITGB4 in HNSCC tissues were evaluated by calculating standard mean differences (SMDs) based on gene chips, RNA-seq, and immunohistochemistry data (n = 2330) from multiple sources. Receiver operating characteristic (ROC) curves were used to detect the ability of ITGB4 to distinguish HNSCC from non-HNSCC samples. The relationship between the expression level of ITGB4 and clinical parameters was evaluated by calculating SMDs. Results: Identical results of mRNA and protein levels indicated remarkable up-expression of ITGB4 in HNSCC tissues. Further ROC curves showed that ITGB4 could distinguish HNSCC from non-HNSCC samples. Genetic alteration analysis of ITGB4 in HNSCC indicated that overexpression of ITGB4 in HNSCC was likely not owing to genetic alteration of ITGB4. Moreover, ITGB4 overexpression level may be correlated with clinical T stage. Conclusion: ITGB4 likely plays an essential role in HNSCC occurrence based on our study and its potential diagnostic value is worthy of further exploration in the future.

Vimentin prevents a miR-dependent negative regulation of tissue factor mRNA during epithelial-mesenchymal transitions and facilitates early metastasis

Epithelial-mesenchymal transitions (EMTs) are high-profile in the field of circulating tumor cells (CTCs). EMT-shifted CTCs are considered to encompass pre-metastatic subpopulations though underlying molecular mechanisms remain elusive. Our previous work identified tissue factor (TF) as an EMT-induced gene providing tumor cells with coagulant properties and supporting metastatic colonization by CTCs. We here report that vimentin, the type III intermediate filament considered a canonical EMT marker, contributes to TF regulation and positively supports coagulant properties and early metastasis. Different evidence further pointed to a new post-transcriptional regulatory mechanism of TF mRNA by vimentin: (1) vimentin silencing accelerated TF mRNA decay after actinomycin D treatment, reflecting TF mRNA stabilization, (2) RNA immunoprecipitation revealed enriched levels of TF mRNA in vimentin immunoprecipitate, (3) TF 3'-UTR-luciferase reporter vector assays implicated the 3'-UTR of TF mRNA in vimentin-dependent TF regulation, and (4) using different TF 3'UTR-luciferase reporter vectors mutated for potential miR binding sites and specific Target Site Blockers identified a key miR binding site in vimentin-dependent TF mRNA regulation. All together, these data support a novel mechanism by which vimentin interferes with a miR-dependent negative regulation of TF mRNA, thereby promoting coagulant activity and early metastasis of vimentin-expressing CTCs.

Vimentin Intermediate Filaments as Potential Target for Cancer Treatment

Intermediate filaments constitute the third component of the cellular skeleton. Unlike actin and microtubule cytoskeletons, the intermediate filaments are composed of a wide variety of structurally related proteins showing distinct expression patterns in tissues and cell types. Changes in the expression patterns of intermediate filaments are often associated with cancer progression; in particular with phenotypes leading to increased cellular migration and invasion. In this review we will describe the role of vimentin intermediate filaments in cancer cell migration, cell adhesion structures, and metastasis formation. The potential for targeting vimentin in cancer treatment and the development of drugs targeting vimentin will be reviewed.

Genome-wide DNA copy number analysis and targeted transcriptional analysis of canine histiocytic malignancies identifies diagnostic signatures and highlights disruption of spindle assembly complex

Canine histiocytic malignancies (HM) are rare across the general dog population, but overrepresented in certain breeds, such as Bernese mountain dog and flat-coated retriever. Accurate diagnosis relies on immunohistochemical staining to rule out histologically similar cancers with different prognoses and treatment strategies (e.g., lymphoma and hemangiosarcoma). HM are generally treatment refractory with overall survival of less than 6 months. A lack of understanding regarding the mechanisms of disease development and progression hinders development of novel therapeutics. While the study of human tumors can benefit veterinary medicine, the rarity of the suggested orthologous disease (dendritic cell sarcoma) precludes this. This study aims to improve the understanding of underlying disease mechanisms using genome-wide DNA copy number and gene expression analysis of spontaneous HM across several dog breeds. Extensive DNA copy number disruption was evident, with losses of segments of chromosomes 16 and 31 detected in 93% and 72% of tumors, respectively. Droplet digital PCR (ddPCR) evaluation of these regions in numerous cancer specimens effectively discriminated HM from other common round cell tumors, including lymphoma and hemangiosarcoma, resulting in a novel, rapid diagnostic aid for veterinary medicine. Transcriptional analysis demonstrated disruption of the spindle assembly complex, which is linked to genomic instability and reduced therapeutic impact in humans. A key signature detected was up-regulation of Matrix Metalloproteinase 9 (MMP9), supported by an immunohistochemistry-based assessment of MMP9 protein levels. Since MMP9 has been linked with rapid metastasis and tumor aggression in humans, the data in this study offer a possible mechanism of aggression in HM.

Tumor necrosis factor-related apoptosis-inducing ligand inhibits the growth and aggressiveness of colon carcinoma via the exogenous apoptosis signaling pathway

Colon cancer is one of the most common types of gastrointestinal tumor. Previous studies have demonstrated that tumor necrosis factor-(TNF)-related apoptosis-inducing ligand (TRAIL) reduces the aggressiveness of colon cancer tumors and promotes the apoptosis of colon carcinoma cells. In the present study, the inhibitory effects of TRAIL were investigated and the potential mechanism of TRAIL-mediated apoptosis was explored in colon cancer cells. Reverse transcription-quantitative polymerase chain reaction, western blotting, immunofluorescence, immunohistochemistry, TUNEL and flow cytometry assays were used to analyze the effects of TRAIL on the growth, migration, invasion and apoptosis of colon tumor cells. In vivo experiments were performed in mice to analyze the therapeutic effects of TRAIL. The results demonstrated that TRAIL significantly suppressed the growth of colorectal tumor cells in a dose-dependent manner (0.5–2.5 mg/ml) and also promoted colon tumor cell death. The migration and invasion of colon tumor cells were inhibited by the downregulation of fibronectin, Vimentin and E-cadherin. The apoptotic rate revealed that TRAIL (2.0 mg/ml) significantly promoted the apoptosis of colon tumor cells by regulating apoptosis-related gene expression. TRAIL administration promoted the apoptosis of colon tumor cells via the exogenous apoptosis signaling pathway due to the upregulation of caspase-3, caspase-8 and nuclear factor-κB protein expression. In vivo assays revealed that TRAIL administration significantly inhibited tumor growth and promoted apoptotic body and lymphocyte infiltration, which led to increased survival in tumor-bearing mice compared with the control group. Immunohistochemistry revealed that P53 and B-cell lymphoma-2 were downregulated in TRAIL-treated tumors. In conclusion, TRAIL treatment significantly inhibited the growth and aggressiveness of colon tumors by inducing apoptosis via the exogenous apoptosis pathway, which suggests that TRAIL may be a potential anticancer agent for colon carcinoma therapy.

Assessment of epithelial-mesenchymal transition signatures in oral submucous fibrosis

Background:

Recently, the concept of field cancerization has questioned the accuracy of biopsy site selection clinically. Oral submucous fibrosis (OSMF) has a global malignant transformation rate of 7.6% despite having less dysplastic changes clinically or histologically. Hence, this study was undertaken to evaluate the expression of vimentin, epithelial-cadherin (E-Cad) and collagen IV in OSMF, using immunohistochemistry and polymerase chain reaction (PCR).

Materials and Methods:

One hundred and eighty- five patients with OSMF (61), with habits and no OSMF (61) and patients without habit and OSMF (63) were subjected to biopsy for sample collection. The samples were analyzed immunohistochemically for vimentin, E-Cad and collagen IV. The PCR values for vimentin and E-Cad were also done.

Results:

Vimentin expression was increased in OSMF patients, whereas E-Cad expression was decreased in OSMF patients.

Conclusion:

Epithelial–mesenchymal transition signatures are definitely positive in OSMF cases.

Complexes of α6β4 integrin and vimentin act as signaling hubs to regulate epithelial cell migration

We find that clusters of β4 integrin, organized into distinct puncta, localize along vimentin filaments within lamellipodia at the cell edge of A549 cells, as assessed by interferometric photoactivated localization microscopy. Moreover, puncta and vimentin filaments exhibit a dynamic interplay in live cells, as viewed by structured-illumination microscopy, with β4 integrin puncta that associate with vimentin persisting for longer than those that do not. Interestingly, in A549 cells β4 integrin regulates vimentin cytoskeleton organization. When β4 integrin is knocked down there is a loss of vimentin filaments from lamellipodia. However, in these conditions, vimentin filaments instead concentrate around the nucleus. Although β4 integrin organization is unaffected in vimentin-deficient A549 cells, such cells move in a less-directed fashion and exhibit reduced Rac1 activity, mimicking the phenotype of β4 integrin-deficient A549 cells. Moreover, in vimentin-deficient cells, Rac1 fails to cluster at sites enriched in α6β4 integrin heterodimers. The aberrant motility of both β4 integrin and vimentin-deficient cells is rescued by expression of active Rac1, leading us to propose that complexes of β4 integrin and vimentin act as signaling hubs, regulating cell motility behavior.

Decoding colorectal cancer epigenomics

Colorectal cancer (CRC) is very heterogeneous and presents different types of epigenetic alterations including DNA methylation, histone modifications and microRNAs. These changes are considered as characteristics of various observed clinical phenotypes. Undoubtedly, the discovery of epigenetic pathways with novel epigenetic-related mechanisms constitutes a promising advance in cancer biomarker discovery. In this review, we provide an evidence-based discussing of the current understanding of CRC epigenomics and its role in initiation, epithelial-to-mesenchymal transition and metastasis. We also discuss the recent findings regarding the potential clinical perspectives of these alterations as potent biomarkers for CRC diagnosis, prognosis, and therapy in the era of liquid biopsy.

Intermediate Filaments at the Junction of Mechanotransduction, Migration, and Development

Mechanically induced signal transduction has an essential role in development. Cells actively transduce and respond to mechanical signals and their internal architecture must manage the associated forces while also being dynamically responsive. With unique assembly-disassembly dynamics and physical properties, cytoplasmic intermediate filaments play an important role in regulating cell shape and mechanical integrity. While this function has been recognized and appreciated for more than 30 years, continually emerging data also demonstrate important roles of intermediate filaments in cell signal transduction. In this review, with a particular focus on keratins and vimentin, the relationship between the physical state of intermediate filaments and their role in mechanotransduction signaling is illustrated through a survey of current literature. Association with adhesion receptors such as cadherins and integrins provides a critical interface through which intermediate filaments are exposed to forces from a cell's environment. As a consequence, these cytoskeletal networks are posttranslationally modified, remodeled and reorganized with direct impacts on local signal transduction events and cell migratory behaviors important to development. We propose that intermediate filaments provide an opportune platform for cells to both cope with mechanical forces and modulate signal transduction.

Vimentin regulates differentiation switch via modulation of keratin 14 levels and their expression together correlates with poor prognosis in oral cancer patients

Vimentin is an intermediate filament protein, predominantly expressed in cells of mesenchymal origin, although its aberrant expression is seen in many carcinomas during epithelial mesenchymal transition. In cancer, vimentin expression is associated with the transition from a more differentiated epithelial phenotype to a dedifferentiated state. In view of the perceived role of keratins (Ks) as regulators of differentiation in epithelia, it was important to understand whether vimentin modulates differentiation through the reprogramming of keratins, in transformed cells. To address this, vimentin was stably downregulated in oral cancer derived cells. Further, global keratin profiling was performed after high salt keratin extraction. K5/K14 pair was found to be significantly downregulated, both at protein and mRNA levels upon vimentin downregulation. The previous study from our laboratory has shown a role of the K5/K14 pair in proliferation and differentiation of squamous epithelial cells. Vimentin depleted cells showed an increase in the differentiation state, marked by an increase in the levels of differentiation specific markers K1, involucrin, filaggrin and loricrin while its proliferation status remained unchanged. Rescue experiments with the K5/K14 pair overexpressed in vimentin knockdown background resulted in decreased differentiation state. ΔNp63 emerged as one of the indirect targets of vimentin, through which it modulates the expression levels of K5/K14. Further, immunohistochemistry showed a significant correlation between high vimentin-K14 expression and recurrence/poor survival in oral cancer patients. Thus, in conclusion, vimentin regulates the differentiation switch via modulation of K5/K14 expression. Moreover, vimentin-K14 together may prove to be the novel markers for the prognostication of human oral cancer.

Effects of epiplakin-knockdown in cultured corneal epithelial cells

BACKGROUND

To investigate effects of knockdown of epiplakin gene expression on the homeostasis of cultured corneal epithelial cell line. We previously reported acceleration of corneal epithelial wound healing in an epiplakin-null mouse.

METHODS

Gene expression of epiplakin was knockdowned by employing siRNA transfection in SV40-immortalized human corneal epithelial cell line. Protein expression of E-cadherin, keratin 6 and vimentin was examined by western blotting. Cell migration and proliferation were examined by using scratch assay and Alamar blue assay, respectively.

RESULTS

Scratch assay and Alamar blue assay showed migration and proliferation of the cells was accelerated by epiplakin knockdown. siRNA-knockdown of epiplakin suppressed protein expression of E-cadherin, keratin 6 and vimentin.

CONCLUSIONS

Decreased expression of E-cadherin, keratin 6 and vimentin might be included in the mechanisms of cell migration acceleration in the absence of epiplakin. The mechanism of cell proliferation stimulation by epiplakin knockdown is to be investigated.