Silencing vimentin expression decreases pulmonary metastases in a pre-diabetic mouse model of mammary tumor progression

Intermittent Fasting Attenuates Obesity-Induced Triple-Negative Breast Cancer Progression by Disrupting Cell Cycle, Epithelial-Mesenchymal Transition, Immune Contexture, and Proinflammatory Signature

Obesity is associated with one-fifth of cancer deaths, and breast cancer is one of the obesity-related cancers. Triple-negative breast cancer (TNBC) lacks estrogen and progesterone receptors and human epidermal growth factor receptor 2, leading to the absence of these therapeutic targets, followed by poor overall survival. We investigated if obesity could hasten TNBC progression and intermittent fasting (IF) could attenuate the progression of obesity-related TNBC. Our meta-analysis of the TNBC outcomes literature showed that obesity led to poorer overall survival in TNBC patients. Fasting-mimicking media reduced cell proliferation disrupted the cell cycle, and decreased cell migration and invasion. IF decreased body weight in obese mice but no change in normal mice. Obese mice exhibited elevated plasma glucose and cholesterol levels, increased tumor volume and weight, and enhanced macrophage accumulation in tumors. The obesity-exacerbated TNBC progression was attenuated after IF, which decreased cyclin B1 and vimentin levels and reduced the proinflammatory signature in the obesity-associated tumor microenvironment. IF attenuated obesity-induced TNBC progression through reduced obesity and tumor burdens in cell and animal experiments, supporting the potential of a cost-effective adjuvant IF therapy for TNBC through lifestyle change. Further evidence is needed of these IF benefits in TNBC, including from human clinical trials.

Serum tumor markers expression (CA199, CA242, and CEA) and its clinical implications in type 2 diabetes mellitus

BACKGROUND

Glucose and lipid metabolic disorder in patients with type 2 diabetes mellitus (T2DM) is associated with the levels of serum tumor markers of the digestive tract, such as cancer antigen (CA)199. Therefore, tumor markers in T2DM are important.

AIM

To evaluate the expression of serum tumor markers [CA199, CA242, and car-cinoembryonic antigen (CEA)] and the clinical implications of the expression in T2DM.

METHODS

For this observational study conducted at Hefei BOE Hospital, China, we enrolled 82 patients with first-onset T2DM and 51 controls between April 2019 and December 2020. Levels of fasting blood glucose (FBG), tumor markers (CA199, CEA, and CA242), glycosylated hemoglobin (HbA1c), etc. were measured and group index levels were compared. Moreover, FBG and HbA1c levels were correlated with tumor marker levels. Tumor markers were tested for diagnostic accuracy in patients with > 9% HbA1c using the receiver operating curve (ROC) curve.

RESULTS

The T2DM group had high serum FBG, HbA1c, CA199, and CEA levels (P < 0.05). A comparative analysis of the two groups based on HbA1c levels (Group A: HbA1c ≤ 9%; Group B: HbA1c > 9%) revealed significant differences in CEA and CA199 levels (P < 0.05). The areas under the ROC curve for CEA and CA199 were 0.853 and 0.809, respectively. CA199, CEA, and CA242 levels positively correlated with HbA1c (r = 0.308, 0.426, and 0.551, respectively) and FBG levels (r = 0.236, 0.231, and 0.298, respectively).

CONCLUSION

As compared to controls, serum CEA and CA199 levels were higher in patients with T2DM. HbA1c and FBG levels correlated with CA199, CEA, and CA242 levels. Patients with poorly controlled blood sugar must be screened for tumor markers.

Changes in serum tumor markers in type 2 diabetes mellitus with microalbuminuria

Objectives

The objective of this study was to investigate changes in serum tumor markers in type 2 diabetes mellitus (T2DM) with microalbuminuria and analyze the relationship between tumor markers and microalbuminuria.

Methods

A total of 956 T2DM patients aged 40-70 years hospitalized in the Department of Endocrinology, Xinhua Hospital, China, affiliated with Shanghai Jiaotong University School of Medicine, were enrolled from January 2018 to December 2020. The sample comprised 313 T2DM patients with microalbuminuria and 643 T2DM patients with normal urinary microalbumin levels. After assessing the changes in serum tumor markers in T2DM with microalbuminuria, we analyzed the risk of microalbuminuria by the serum tumor marker category using multiple logistic regression analysis.

Results

Serum CEA, CA199, CA125, CA153, CA211, SCC, CA242, and CA50 levels were significantly higher in T2DM patients with microalbuminuria than in those without microalbuminuria, while serum AFP levels were lower in the microalbuminuria group (P < 0.05). Following adjustment of confounders, serum CEA, CA211, and SCC were independently associated with microalbuminuria in T2DM. An ROC curve was used to estimate the cutoff point of tumor markers for microalbuminuria. Taking the values under the cutoff points as a reference, values for CEA, CA211, and SCC above the cutoff points indicated a significantly high risk of microalbuminuria. The OR of increased CEA for microalbuminuria was 2.006 (95%CI 1.456-2.765), the OR of increased CA211 for microalbuminuria was 1.505 (95%CI 1.092-2.074), and the OR of increased SCC for microalbuminuria was 1.958 (95%CI 1.407-2.724).

Conclusion

Several serum tumor markers were related to microalbuminuria in T2DM. Serum tumor markers such as CEA, SCC, and CA211 may indicate early diabetic nephropathy, particularly when elevated in combination.

Vimentin is required for tumor progression and metastasis in a mouse model of non-small cell lung cancer

Vimentin is highly expressed in metastatic cancers, and its expression correlates with poor patient prognoses. However, no causal in vivo studies linking vimentin and non-small cell lung cancer (NSCLC) progression existed until now. We use three complementary in vivo models to show that vimentin is required for the progression of NSCLC. First, we crossed LSL-Kras^G12D; Tp53^fl/fl mice (KPV^+/+) with vimentin knockout mice (KPV^-/-) to demonstrate that KPV^-/- mice have attenuated tumor growth and improved survival compared with KPV^+/+ mice. Next, we therapeutically treated KPV^+/+ mice with withaferin A (WFA), an agent that disrupts vimentin intermediate filaments (IFs). We show that WFA suppresses tumor growth and reduces tumor burden in the lung. Finally, luciferase-expressing KPV^+/+, KPV^-/-, or KPV^Y117L cells were implanted into the flanks of athymic mice to track cancer metastasis to the lung. In KPV^Y117L cells, vimentin forms oligomers called unit-length filaments but cannot assemble into mature vimentin IFs. KPV^-/- and KPV^Y117L cells fail to metastasize, suggesting that cell-autonomous metastasis requires mature vimentin IFs. Integrative metabolomic and transcriptomic analysis reveals that KPV^-/- cells upregulate genes associated with ferroptosis, an iron-dependent form of regulated cell death. KPV^-/- cells have reduced glutathione peroxidase 4 (GPX4) levels, resulting in the accumulation of toxic lipid peroxides and increased ferroptosis. Together, our results demonstrate that vimentin is required for rapid tumor growth, metastasis, and protection from ferroptosis in NSCLC.

A Novel Detection Method of Breast Cancer through a Simple Panel of Biomarkers

Circulating tumor cells (CTCs) have been identified as responsible for the spread of tumors to other organs of the body. In this sense, the development of sensitive and specific assays for their detection is important to reduce the number of deaths due to metastases. Here, we assessed whether the detection of CTCs in peripheral blood can serve in the construction of a panel of diagnosis and monitoring treatments of breast cancer (BC), focusing on the expression of markers of epithelial-mesenchymal transition. Through analyzing the blood from women without breast alterations (control), women with benign alterations, women with breast cancer without chemotherapy, and women with breast cancer with chemotherapy, we identified the best markers by transcriptional levels and determined three profiles of CTCs (mesenchymal, intermediate, and epithelial) by flow cytometry which, combined, can be used for diagnosis and therapy monitoring with sensitivity and specificity between 80% and 100%. Therefore, we have developed a method for detecting breast cancer based on the analysis of CTC profiles by epithelial-mesenchymal transition markers which, combined, can be used for the diagnosis and monitoring of therapy.

Integrin α6β4 requires plectin and vimentin for adhesion complex distribution and invasive growth

Integrin α6β4 binds plectin to associate with vimentin; however, the biological function remains unclear. Here, we utilized various integrin β4 mutants and CRISPR-Cas9 editing to investigate this association. Upon laminin binding, integrin α6β4 distinctly distributed peripherally as well as centrally, proximal to the nucleus. Upon fibronectin addition, integrin α6β4 was centrally recruited to large focal adhesions (FAs) and enhanced Fak (also known as PTK2) phosphorylation. Integrin β4 plectin-binding mutants or genetic deletion of plectin inhibited β4 recruitment to FAs and integrin α6β4-enhanced cell spreading, migration and three-dimensional invasive growth. Loss of the β4 signaling domain (but retaining plectin binding) blocked migration and invasiveness but not cell spreading, recruitment to FAs or colony growth. Immunostaining revealed that integrin α6β4 redistributed vimentin perinuclearly, where it colocalized with plectin and FAs. Depletion of vimentin completely blocked integrin β4-enhanced invasive growth, Fak phosphorylation and proliferation in three dimensions but not two dimensions. In summary, we demonstrate the essential roles of plectin and vimentin in promoting an invasive phenotype downstream of integrin α6β4. This article has an associated First Person interview with the first author of the paper.

TMEM176B Regulates AKT/mTOR Signaling and Tumor Growth in Triple-Negative Breast Cancer

TMEM176B is a member of the membrane spanning 4-domains (MS4) family of transmembrane proteins, and a putative ion channel that is expressed in immune cells and certain cancers. We aimed to understand the role of TMEM176B in cancer cell signaling, gene expression, cell proliferation, and migration in vitro, as well as tumor growth in vivo. We generated breast cancer cell lines with overexpressed and silenced TMEM176B, and a therapeutic antibody targeting TMEM176B. Proliferation and migration assays were performed in vitro, and tumor growth was evaluated in vivo. We performed gene expression and Western blot analyses to identify the most differentially regulated genes and signaling pathways in cells with TMEM176B overexpression and silencing. Silencing TMEM176B or inhibiting it with a therapeutic antibody impaired cell proliferation, while overexpression increased proliferation in vitro. Syngeneic and xenograft tumor studies revealed the attenuated growth of tumors with TMEM176B gene silencing compared with controls. We found that the AKT/mTOR signaling pathway was activated or repressed in cells overexpressing or silenced for TMEM176B, respectively. Overall, our results suggest that TMEM176B expression in breast cancer cells regulates key signaling pathways and genes that contribute to cancer cell growth and progression, and is a potential target for therapeutic antibodies.

Vimentin Promotes the Aggressiveness of Triple Negative Breast Cancer Cells Surviving Chemotherapeutic Treatment

Tremendous data have been accumulated in the effort to understand chemoresistance of triple negative breast cancer (TNBC). However, modifications in cancer cells surviving combined and sequential treatment still remain poorly described. In order to mimic clinical neoadjuvant treatment, we first treated MDA-MB-231 and SUM159-PT TNBC cell lines with epirubicin and cyclophosphamide for 2 days, and then with paclitaxel for another 2 days. After 4 days of recovery, persistent cells surviving the treatment were characterized at both cellular and molecular level. Persistent cells exhibited increased growth and were more invasive in vitro and in zebrafish model. Persistent cells were enriched for vimentin^high sub-population, vimentin knockdown using siRNA approach decreased the invasive and sphere forming capacities as well as Akt phosphorylation in persistent cells, indicating that vimentin is involved in chemotherapeutic treatment-induced enhancement of TNBC aggressiveness. Interestingly, ectopic vimentin overexpression in native cells increased cell invasion and sphere formation as well as Akt phosphorylation. Furthermore, vimentin overexpression alone rendered the native cells resistant to the drugs, while vimentin knockdown rendered them more sensitive to the drugs. Together, our data suggest that vimentin could be considered as a new targetable player in the ever-elusive status of drug resistance and recurrence of TNBC.

Tumor microenvironment acidity modulates ROR1 to promote epithelial-mesenchymal transition and hepatocarcinoma metastasis

The tendency of hepatocarcinoma to metastasize results in a high rate of mortality, making it a hot research topic in cancer studies. Although an acidic tumor microenvironment has been proven to promote cancer metastasis, the underlying regulatory mechanisms remain poorly defined. Here, we found that acidic conditions significantly enhanced cell migration and invasion ability in hepatocellular carcinoma, and the expression of receptor tyrosine kinase-like orphan receptor 1 (ROR1) was distinctly upregulated in acid-treated cells. In addition, siRNA-mediated knockdown of ROR1 could effectively inhibit acid-induced cell migration, invasion and epithelial-mesenchymal transition (EMT). Importantly, neutralization of acidic environments with NaHCO3 could downregulate acid-stimulated ROR1 expression, thereby retarding cell metastatic potential. Notably, the formation of metastatic nodules was significantly increased after intrapulmonary injection of acid-stimulated cancer cells, and this was inhibited by pretreating with NaHCO3. In summary, we reveal that an acidic tumor microenvironment modulates ROR1 expression to promote tumor metastasis, providing not only a better understanding of molecular mechanisms related to metastasis, but also a promising target for tumor management.

Correlation of serum CA199 levels with glycemic control and microvascular complications in patients with type 2 diabetes mellitus

OBJECTIVE

This study aimed to explore the correlation between glycemic control, microvascular complications and serum glycogen antigen (CA199) in patients with type 2 diabetes mellitus (T2DM).

METHODS

519 patients with T2DM admitted to our hospital were included. All patients had CA199 levels measured. Patients were divided into low glycation (LH) group (HbA1C <7.5%), Hyperglycemia (HH) group (HbA1C ≥7.5%), fasting glucose compliance (SF) group (FBG <7.0 mmol/L), high fasting glucose (HF) group (FBG ≥7.0 mmol/L), postprandial glucose compliance (SP) group (PBG <10.0 mmol/L) and high postprandial glucose (HP) group (PBG ≥10.0 mmol/L) and with microvascular complications group, and no microvascular complications group. Division was according to levels of glycated hemoglobin (HbA1C), fasting blood glucose (FBG), 2-hour postprandial blood glucose (2hPBG), and diabetic microvascular complications.

RESULTS

CA199 levels were significantly higher in the HH and HF groups than in the LH and SF groups (P<0.05); HbA1C and FBG were positively correlated with CA199; CA199 levels were not significantly different between SP and HP groups (P>0.05), and PBG was not significantly correlated with CA199 levels. CA199 levels were significantly higher in the group with microvascular complications than in the group without microvascular complications (P<0.05); HbA1C was an independent risk factor for elevated CA199.

CONCLUSION

Patients with T2DM and higher CA199 levels need to be evaluated for glycemic status and the presence of microvascular complications. HbA1C is a major risk factor for elevated CA199 levels.

Myocardial Infarction Induces Cardiac Fibroblast Transformation within Injured and Noninjured Regions of the Mouse Heart

Heart failure (HF) is associated with pathological remodeling of the myocardium, including the initiation of fibrosis and scar formation by activated cardiac fibroblasts (CFs). Although early CF-dependent scar formation helps prevent cardiac rupture by maintaining the heart's structural integrity, ongoing deposition of the extracellular matrix in the remote and infarct regions can reduce tissue compliance, impair cardiac function, and accelerate progression to HF. In our study, we conducted mass spectrometry (MS) analysis to identify differentially altered proteins and signaling pathways between CFs isolated from 7 day sham and infarcted murine hearts. Surprisingly, CFs from both the remote and infarct regions of injured hearts had a wide number of similarly altered proteins and signaling pathways that were consistent with fibrosis and activation into pathological myofibroblasts. Specifically, proteins enriched in CFs isolated from MI hearts were involved in pathways pertaining to cell-cell and cell-matrix adhesion, chaperone-mediated protein folding, and collagen fibril organization. These results, together with principal component analyses, provided evidence of global CF activation postinjury. Interestingly, however, direct comparisons between CFs from the remote and infarct regions of injured hearts identified 15 differentially expressed proteins between MI remote and MI infarct CFs. Eleven of these proteins (Gpc1, Cthrc1, Vmac, Nexn, Znf185, Sprr1a, Specc1, Emb, Limd2, Pawr, and Mcam) were higher in MI infarct CFs, whereas four proteins (Gstt1, Gstm1, Tceal3, and Inmt) were higher in MI remote CFs. Collectively, our study shows that MI injury induced global changes to the CF proteome, with the magnitude of change reflecting their relative proximity to the site of injury.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

Biointerface anisotropy modulates migration of breast cancer cell

Migration of cancer cell is a cyclic process, which involves dynamic interaction between extracellular biointerface and cellular responds. In tumors, collagen as extracellular matrix reorganizes biointerface from curl and isotropic fibers to straightened and anisotropic fibers during tumorigenesis, yet how cell migration respond to topography of biointerface is unknown. In this research, we introduced a facile fabrication method on nanofibers of varying topography, which was mimicking the alignment of extracellular nanofibers, to examine the change of cytoskeleton during cell migration. We took advantage of breast carcinoma cell line (MDA-MB-231) for time-lapse imaging analysis. We found that biointerface anisotropy modulated morphology of cell and mediated the pattern of migration. Morphologically, cells on anisotropic nanofiber showed extending spindle shape. The trajectories of migration templated the topographic pattern on biointerface. Besides, aligned nanofiber induced caterpillar-like model of migration through protrusion - retraction cycle, which was indicated by periodical variation of aspect ratio and velocity of cells. The biointerface anisotropy triggered vimentin filaments and microtubule networks preferentially oriented along the alignment of nanofibers. And the velocity of cell mobility by vimentin, β-catenin or CDC42 knockdown was significantly enhanced on aligned nanofibers. Thus, we implied that biointerface anisotropy modulated migration of breast cancer cell and it associated with reorganization of cytoskeleton filaments.

Nanofiber Alignment Mediates the Pattern of Single Cell Migration

In natural tissue, nanofibrils in extracellular matrix (ECM), such as collagen fibrils, direct cell migration through contacting guidance. The contacting nanofibers on cell-ECM interface are reorganized from curl fibers to straightened fibers. However, how these nanofibers regulate single cell migration remains obscure. To investigate this issue, we fabricated collagen/polymer based biomimetic nanofiber sheets of varying topography. And we selected tumorigenic cell KGN and nontumorigenic cell 293T for comparison. We found KGN showed higher sensitivity to the nanofiber alignment rather than the nontumorigenic cell 293T, in morphological change, trajectory adaptation, and velocity variation. We also found aligned nanofibers shaped both KGN and 293T into elongated spindle morphology. Comparatively, KGN had greater perimeter and lower roundness than 293T. To study the dynamics of single cell migration of KGN and 293T, we conducted trajectory tracking and siRNA validation on regulatory proteins. We found nanofibers of varying topography regulated the patterns of single cell migration differently. For KGN cell, β-catenin, Rac1, and Cdc42 participated in its directional migration, but it was impervious to vimentin. Comparatively, epithelial cell 293T involved vimentin in its directional migration.

Upregulation of Epithelial-To-Mesenchymal Transition Markers and P2X7 Receptors Is Associated to Increased Invasiveness Caused by P2X7 Receptor Stimulation in Human Glioblastoma Stem Cells

Glioblastoma (GBM) stem cells (GSCs), which contribute to GBM unfavorable prognosis, show high expression levels of ATP/P2X7 receptors (P2X7R). Here, we reported that cells exposure to 2’(3’)-O-(4-benzoylbenzoyl)-ATP (BzATP), a P2X7R agonist, up-regulated the expression of markers associated to epithelial-to-mesenchymal transition (EMT), a process likely contributing to GSC malignancy, and increased GSC migration/invasiveness like the known EMT inducer, Transforming Growth Factor β1 (TGFβ1). These effects were coupled to phosphorylation of SMAD2, a downstream effector in the TGFβ pathway, suggesting its involvement in P2X7R-mediated activity in GSCs. All BzATP effects, including a decrease in the caspase 3/7 activity in GSC medium, were mostly counteracted by the P2X7R antagonist A438079. Finally, BzATP increased the subunit expression of two main human P2X7R splice variants, the full-length P2X7A and the truncated P2X7B, lacking the carboxylic tail, which have different functional properties depending on their arrangement. Since up-regulation of A/B subunits might favor their assembly into a heterotrimeric P2X7R with great sensitivity towards agonists and cell energy support, this is in line with increased EMT markers expression, cell migration/invasion and GSC survival observed following P2X7R stimulation. As in GBM microenvironment extracellular ATP levels may activate P2X7R, our data suggest a P2X7R role in GBM recurrence/invasiveness.

The anti-migration and anti-invasion effects of Bruceine D in human triple-negative breast cancer MDA-MB-231 cells

Brucein D (BD) is a naturally occurring major active quassinoid extracted from the Chinese medicinal herb Brucea javanica, which has been previously demonstrated to exhibit anticancer activities. The present study aimed to investigate the anticancer effects of BD on MDA-MB-231 cells, a human triple-negative breast cancer (TNBC) cell line. An MTT assay was performed to assess cell viability, whilst wound healing and Transwell assay were applied to measure cell migration and invasion, respectively. Western blot analysis was performed to assess the expression of E-cadherin, vimentin and β-catenin, which are proteins associated with epithelial-mesenchymal transformation (EMT), and PI3K, AKT and p-AKT, which are key components of the PI3K/AKT signaling pathway. BD was indicated to reduce cell viability in a dose- and time-dependent manner, whilst cell invasion and migration were also significantly inhibited in a dose-dependent manner. Western blot analysis demonstrated that BD treatment significantly upregulated the expression of E-cadherin and downregulated the expression of vimentin and β-catenin. Additionally, BD downregulated the expression of PI3K and reduced AKT phosphorylation. In conclusion, BD can inhibit MDA-MB-231 cell viability, migration and invasion, suggesting the potential use of BD for the treatment of TNBC.

Pathophysiology of Tumor Cell Release into the Circulation and Characterization of CTC

The traditional model of metastatic progression postulates that the ability to form distant metastases is driven by random mutations in cells of the primary tumor.

Intermediate Filaments as Effectors of Cancer Development and Metastasis: A Focus on Keratins, Vimentin, and Nestin

Intermediate filament (IF) proteins make up the largest family of cytoskeletal proteins in metazoans, and are traditionally known for their roles in fostering structural integrity in cells and tissues. Remarkably, individual IF genes are tightly regulated in a fashion that reflects the type of tissue, its developmental and differentiation stages, and biological context. In cancer, IF proteins serve as diagnostic markers, as tumor cells partially retain their original signature expression of IF proteins. However, there are also characteristic alterations in IF gene expression and protein regulation. The use of high throughput analytics suggests that tumor-associated alterations in IF gene expression have prognostic value. Parallel research is also showing that IF proteins directly and significantly impact several key cellular properties, including proliferation, death, migration, and invasiveness, with a demonstrated impact on the development, progression, and characteristics of various tumors. In this review, we draw from recent studies focused on three IF proteins most associated with cancer (keratins, vimentin, and nestin) to highlight how several “hallmarks of cancer” described by Hanahan and Weinberg are impacted by IF proteins. The evidence already in hand establishes that IF proteins function beyond their classical roles as markers and serve as effectors of tumorigenesis.

Vimentin on the move: new developments in cell migration

The vimentin gene ( VIM) encodes one of the 71 human intermediate filament (IF) proteins, which are the building blocks of highly ordered, dynamic, and cell type-specific fiber networks. Vimentin is a multi-functional 466 amino acid protein with a high degree of evolutionary conservation among vertebrates. Vim ^−/− mice, though viable, exhibit systemic defects related to development and wound repair, which may have implications for understanding human disease pathogenesis. Vimentin IFs are required for the plasticity of mesenchymal cells under normal physiological conditions and for the migration of cancer cells that have undergone epithelial–mesenchymal transition. Although it was observed years ago that vimentin promotes cell migration, the molecular mechanisms were not completely understood. Recent advances in microscopic techniques, combined with computational image analysis, have helped illuminate vimentin dynamics and function in migrating cells on a precise scale. This review includes a brief historical account of early studies that unveiled vimentin as a unique component of the cell cytoskeleton followed by an overview of the physiological vimentin functions documented in studies on Vim ^−/− mice. The primary focus of the discussion is on novel mechanisms related to how vimentin coordinates cell migration. The current hypothesis is that vimentin promotes cell migration by integrating mechanical input from the environment and modulating the dynamics of microtubules and the actomyosin network. These new findings undoubtedly will open up multiple avenues to study the broader function of vimentin and other IF proteins in cell biology and will lead to critical insights into the relevance of different vimentin levels for the invasive behaviors of metastatic cancer cells.

MIND model for triple-negative breast cancer in syngeneic mice for quick and sequential progression analysis of lung metastasis

Mouse models of breast cancer with specific molecular subtypes (e.g., ER or HER2 positive) in an immunocompetent or an immunocompromised environment significantly contribute to our understanding of cancer biology, despite some limitations, and they give insight into targeted therapies. However, an ideal triple-negative breast cancer (TNBC) mouse model is lacking. What has been missing in the TNBC mouse model is a sequential progression of the disease in an essential native microenvironment. This notion inspired us to develop a TNBC-model in syngeneic mice using a mammary intraductal (MIND) method. To achieve this goal, Mvt-1and 4T1 TNBC mouse cell lines were injected into the mammary ducts via nipples of FVB/N mice and BALB/c wild-type immunocompetent mice, respectively. We established that the TNBC-MIND model in syngeneic mice could epitomize all breast cancer progression stages and metastasis into the lungs via lymphatic or hematogenous dissemination within four weeks. Collectively, the syngeneic mouse-TNBC-MIND model may serve as a unique platform for further investigation of the underlying mechanisms of TNBC growth and therapies.

Discoidin domain receptor 1 (DDR1) ablation promotes tissue fibrosis and hypoxia to induce aggressive basal-like breast cancers

Here, Takai et al. researched the function of discoidin domain receptor 1 (DDR1), a member of the subfamily of receptor tyrosine kinases activated by collagens that is overexpressed in breast and other carcinoma cells. Using bioinformatics analysis, breast cancer cell lines, and knockout mice, they demonstrate that DDR1 ablation leads to aggressive breast cancer, and their findings suggest that the absence of DDR1 provides a growth and adhesion advantage that favors the expansion of basal cells, potentiates fibrosis, and enhances necrosis/hypoxia and basal differentiation of transformed cells to increase their aggression and metastatic potential.

The discoidin domain receptor 1 (DDR1) is overexpressed in breast carcinoma cells. Low DDR1 expression is associated with worse relapse-free survival, reflecting its controversial role in cancer progression. We detected DDR1 on luminal cells but not on myoepithelial cells of DDR1^+/+ mice. We found that DDR1 loss compromises cell adhesion, consistent with data that older DDR1^−/− mammary glands had more basal/myoepithelial cells. Basal cells isolated from older mice exerted higher traction forces than the luminal cells, in agreement with increased mammary branches observed in older DDR1^−/− mice and higher branching by their isolated organoids. When we crossed DDR1^−/− mice with MMTV-PyMT mice, the PyMT/DDR1^−/− mammary tumors grew faster and had increased epithelial tension and matricellular fibrosis with a more basal phenotype and increased lung metastases. DDR1 deletion induced basal differentiation of CD90⁺CD24⁺ cancer cells, and the increase in basal cells correlated with tumor cell mitoses. K14⁺ basal cells, including K8⁺K14⁺ cells, were increased adjacent to necrotic fields. These data suggest that the absence of DDR1 provides a growth and adhesion advantage that favors the expansion of basal cells, potentiates fibrosis, and enhances necrosis/hypoxia and basal differentiation of transformed cells to increase their aggression and metastatic potential.

Emerging roles and mechanisms of FOXC2 in cancer

Forkhead box protein C2 (FOXC2), a transcription factor of the forkhead/winged-helix family, is required for embryonic and prenatal development. FOXC2 acts as a crucial modulator during both angiogenesis and lymphangiogenesis via multiple angiogenic and lymphangiogenic pathways, respectively. Although recent studies have shed light on the emerging role of FOXC2 in cancer, very little is known about the precise underlying mechanisms. The purpose of this review is to summarize the current understanding of FOXC2 and provide potential mechanistic explanations of the relationship between FOXC2 and cancer, as well as discuss the prospect for future research in the promising prognostic value of FOXC2 in cancer.

High content image analysis reveals function of miR-124 upstream of Vimentin in regulating motor neuron mitochondria

microRNAs (miRNAs) are critical for neuronal function and their dysregulation is repeatedly observed in neurodegenerative diseases. Here, we implemented high content image analysis for investigating the impact of several miRNAs in mouse primary motor neurons. This survey directed our attention to the neuron-specific miR-124, which controls axonal morphology. By performing next generation sequencing analysis and molecular studies, we characterized novel roles for miR-124 in control of mitochondria localization and function. We further demonstrated that the intermediate filament Vimentin is a key target of miR-124 in this system. Our data establishes a new pathway for control of mitochondria function in motor neurons, revealing the value of a neuron-specific miRNA gene as a mechanism for the re-shaping of otherwise ubiquitously-expressed intermediate filament network, upstream of mitochondria activity and cellular metabolism.

Antioxydation And Cell Migration Genes Are Identified as Potential Therapeutic Targets in Basal-Like and BRCA1 Mutated Breast Cancer Cell Lines

Basal-like breast cancers are among the most aggressive cancers and effective targeted therapies are still missing. In order to identify new therapeutic targets, we performed Methyl-Seq and RNA-Seq of 10 breast cancer cell lines with different phenotypes. We confirmed that breast cancer subtypes cluster the RNA-Seq data but not the Methyl-Seq data. Basal-like tumor hypermethylated phenotype was not confirmed in our study but RNA-Seq analysis allowed to identify 77 genes significantly overexpressed in basal-like breast cancer cell lines. Among them, 48 were overexpressed in triple negative breast cancers of TCGA data. Some molecular functions were overrepresented in this candidate gene list. Genes involved in antioxydation, such as SOD1, MGST3 and PRDX or cadherin-binding genes, such as PFN1, ITGB1 and ANXA1, could thus be considered as basal like breast cancer biomarkers. We then sought if these genes were linked to BRCA1, since this gene is often inactivated in basal-like breast cancers. Nine genes were identified overexpressed in both basal-like breast cancer cells and BRCA1 mutated cells. Amongst them, at least 3 genes code for proteins implicated in epithelial cell migration and epithelial to mesenchymal transition (VIM, ITGB1 and RhoA). Our study provided several potential therapeutic targets for triple negative and BRCA1 mutated breast cancers. It seems that migration and mesenchymal properties acquisition of basal-like breast cancer cells is a key functional pathway in these tumors with a high metastatic potential.

Epithelial vimentin plays a functional role in mammary gland development

In the mammary gland, vimentin intermediate filaments are expressed in stromal cells and in basal epithelial cell populations, including gland-reconstituting mammary stem cells, with largely undefined functions. Here, we have studied how vimentin deficiency affects mouse mammary gland development. We find that, in adult vimentin knockout mice (Vim^-/- ), mammary ductal outgrowth is delayed. The adult Vim^-/- glands display dilated ducts and a reduced basal-to-luminal mouse mammary epithelial cell (MMEC) ratio indicative of altered progenitor cell activity. Accordingly, isolated Vim^-/- MMECs form fewer mammospheres and basal-like organoids in vitro than their wild-type counterparts. Importantly, reduced basal MMEC number translates into defects in Vim^-/- mammary gland regeneration in vivo Global gene expression profiling of basal MMECs reveals that lack of vimentin alters multiple pathways, including adhesion, cancer and Wnt signalling. Furthermore, vimentin contributes to stem-like cell properties in MDA-MB-231 breast cancer cells, wherein vimentin depletion reduces tumoursphere formation and attenuates expression of breast cancer stem cell-associated surface markers. Together, our findings identify vimentin as a positive regulator of stemness in the developing mouse mammary gland and in breast cancer cells.

Elevated tumor LDLR expression accelerates LDL cholesterol-mediated breast cancer growth in mouse models of hyperlipidemia

Obesity is associated with an increase in cancer-specific mortality in women with breast cancer. Elevated cholesterol, particularly low-density lipoprotein cholesterol (LDL-C) is frequently seen in obese women. Here, we aimed to determine the importance of elevated circulating LDL, and LDL receptor (LDLR) expression in tumor cells, on the growth of breast cancer using mouse models of hyperlipidemia. We describe two novel immunodeficient mouse models of hyperlipidemia (Rag1^−/−/LDLR^−/− and Rag1^−/−/ApoE (apolipoprotein E)^−/− mice), in addition to established immunocompetent LDLR^−/− and ApoE^−/− mice. The mice were used to study the effects of elevated LDL-C in human triple negative (MDA-MB-231) and mouse Her2/Neu overexpressing (MCNeuA) breast cancers. Tumors derived from MCNeuA and MDA-MB-231 cells had high LDLR expression and formed larger tumors in mice with high circulating LDL-C concentrations than in mice with lower LDL-C. Silencing the LDLR in the tumor cells led to decreased growth of Her2Neu overexpressing tumors in LDLR^−/− and ApoE^−/− mice, with increased Caspase 3 cleavage. Additionally, in vitro, silencing the LDLR led to decreased cell survival in serum-starved conditions, associated with Caspase 3 cleavage. Examining publically available human datasets, we found that high LDLR expression in human breast cancers was associated with decreased recurrence-free survival, particularly in patients treated with systemic therapies. Overall, our results highlight the importance of the LDLR in the growth of triple negative and HER2 overexpressing breast cancers in the setting of elevated circulating LDL-C, which may be important contributing factors to the increased recurrence and mortality in obese women with breast cancer.

Vimentin is a crucial target for anti-metastasis therapy of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a unique subtype of head and neck cancer, with tendency to spread to regional lymph nodes and distant organs at early stage. Vimentin, a major cytoskeletal protein constituent of the intermediate filament, plays a critical role in the epithelial-mesenchymal transition. Overexpression of vimentin is considered to be a critical prerequisite for metastasis in numerous human cancers. Therefore, targeting vimentin for cancer therapy has gained a lot of interest. In the present study, we detected vimentin expression in NPC tissues and found that overexpression of vimentin is associated with poor prognosis of NPC patients. Silencing of vimentin in NPC CNE2 cells by RNAi suppresses cells migration and invasion in vitro. However, blocking vimentin did not affect cell proliferation of CNE2 cells. In addition, the in vivo metastatic potential of CNE2 cells transfected with Vimentin shRNA was suppressed in a nude mouse model of pulmonary metastasis. Silencing of Vimentin in CNE2 cells leads to a decrease of microvessel density and VEGF, CD31, MMP2, and MMP9 expressions in pulmonary metastatic tumors. Importantly, we found that it is easier for the tumor cells from the high vimentin-expressing pulmonary metastatic tumors to reinvade the microvessel and to form stable tumor plaques attached to the endothelial cells, which resemble the resource of circulating tumor cells and are very hard to eliminate. However, depletion of vimentin inhibits the formation of vascular tumor plaques. Our findings suggest that RNAi-based vimentin silencing may be a potential and promising anti-metastatic therapeutic strategy for NPC.

URI promotes the migration and invasion of human cervical cancer cells potentially via upregulation of vimentin expression

URI is known to act as an oncoprotein in several tumors. Our previous studies have shown that URI is associated with the migration process in cervical and gastric cancer cells, but the mechanisms remain to be determined. Given the fact that URI positively regulates vimentin expression, we therefore investigated how URI regulated vimentin expression affects the migration and invasion of cells from two human cervical cancer cell lines HeLa and C33A, which differentially express URI. We have shown that knock-down of URI in HeLa cells using URI siRNA caused decreased vimentin mRNA and protein levels along with attenuated cell motility. Meanwhile, overexpression of URI by transfection of PCMV6-URI in C33A cells resulted in increased vimentin expression and enhanced cell migration and invasion. We have also used TGF-β to induce vimentin expression, which enhanced the cell migration and invasion abilities affected by URI, while inhibition of vimentin by siRNA attenuated URI's effect on cell migration and invasion. In addition, we have performed luciferase reporter and ChIP assays, and the results support that URI indirectly enhances the activity of vimentin promoter. Taken together, our results suggest that URI plays essential roles in the migration and invasion of human cervical cancer cells, possibly via targeting vimentin expression.

Insights into the Link Between Obesity and Cancer

PURPOSE OF REVIEW

Adipocytes have adapted to store energy in the form of lipid and also secrete circulating factors called adipokines that signal to other tissues to coordinate energy homeostasis. These functions are disrupted in the setting of obesity, promoting the development of diseases such as diabetes, cardiovascular disease, and cancer.

RECENT FINDINGS

Obesity is linked to an increased risk of many types of cancer and increased cancer-related mortality. The basis for the striking association between obesity and cancer is not well understood. Here, we review the cellular and molecular pathways that appear to be involved in obesity-driven cancer. We also describe possible therapeutic considerations and highlight important unanswered questions in the field.

For robust big data analyses: a collection of 150 important pro-metastatic genes

Metastasis is the greatest contributor to cancer-related death. In the era of precision medicine, it is essential to predict and to prevent the spread of cancer cells to significantly improve patient survival. Thanks to the application of a variety of high-throughput technologies, accumulating big data enables researchers and clinicians to identify aggressive tumors as well as patients with a high risk of cancer metastasis. However, there have been few large-scale gene collection studies to enable metastasis-related analyses. In the last several years, emerging efforts have identified pro-metastatic genes in a variety of cancers, providing us the ability to generate a pro-metastatic gene cluster for big data analyses. We carefully selected 285 genes with in vivo evidence of promoting metastasis reported in the literature. These genes have been investigated in different tumor types. We used two datasets downloaded from The Cancer Genome Atlas database, specifically, datasets of clear cell renal cell carcinoma and hepatocellular carcinoma, for validation tests, and excluded any genes for which elevated expression level correlated with longer overall survival in any of the datasets. Ultimately, 150 pro-metastatic genes remained in our analyses. We believe this collection of pro-metastatic genes will be helpful for big data analyses, and eventually will accelerate anti-metastasis research and clinical intervention.

Activating Transcription Factor-5 Knockdown Reduces Aggressiveness of Mammary Tumor Cells and Attenuates Mammary Tumor Growth

Activating transcription factor-5 (ATF5) is an anti-apoptotic factor and has been implicated in enhancing the survival of cancer cells under stress and in regulating the autophagy process. Targeting ATF5 in anticancer therapy may be particularly attractive because of its differential role in cancer cells than in non-transformed cells, thus allowing specificity of the treatment. Using the delivery of short hairpin RNA vectors into the Mvt1 and Met1 cell lines, we tested the role of ATF5 in the development of mammary tumors in vivo and in regulating proliferation and migration of these cells in vitro. In this study, we demonstrate that knockdown of ATF5 (ATF5-KD) in both cell lines results in a decreased tumor volume and weight, as well as in a reduced proliferation rate and migratory potential of the cells. In addition, ATF5-KD led to an increased autophagy flux and a shift in the sub-populations comprising Mvt1 cells from the aggressive CD24-positive cells toward less aggressive CD24-negative cells. Taken together, these findings suggest that ATF5 plays an important role in enhancing mammary tumor cells overall aggressiveness and in promoting mammary tumor growth and emphasize the possible benefit of anti-ATF5 therapy in breast cancer patients, particularly, against tumors characterized with the positive expression of cell surface CD24.