Nuclear factor-inducing kinase plays a crucial role in osteopontin-induced MAPK/IkappaBalpha kinase-dependent nuclear factor kappaB-mediated promatrix metalloproteinase-9 activation

Thrombin Cleavage of Osteopontin and the Host Anti-Tumor Immune Response

Osteopontin (OPN) is a multi-functional protein that is involved in various cellular processes such as cell adhesion, migration, and signaling. There is a single conserved thrombin cleavage site in OPN that, when cleaved, yields two fragments with different properties from full-length OPN. In cancer, OPN has tumor-promoting activity and plays a role in tumor growth and metastasis. High levels of OPN expression in cancer cells and tumor tissue are found in various types of cancer, including breast, lung, prostate, ovarian, colorectal, and pancreatic cancer, and are associated with poor prognosis and decreased survival rates. OPN promotes tumor progression and invasion by stimulating cell proliferation and angiogenesis and also facilitates the metastasis of cancer cells to other parts of the body by promoting cell adhesion and migration. Furthermore, OPN contributes to immune evasion by inhibiting the activity of immune cells. Thrombin cleavage of OPN initiates OPN's tumor-promoting activity, and thrombin cleavage fragments of OPN down-regulate the host immune anti-tumor response.

OPN Promotes Cell Proliferation and Invasion through NF-κB in Human Esophageal Squamous Cell Carcinoma

Background

Osteopontin (OPN) is a phosphorylated glycoprotein. There is increasing evidence that the OPN gene played a major role in the progression of solid organ tumors. However, few studies have clarified how OPN regulated the functional role of human esophageal squamous cell carcinoma (ESCC). This study was designed to investigate the effect of OPN in esophageal squamous cell carcinoma.

Methods

First, we screened Eca-109 and KYSE-510 cells to construct OPN silencing and overexpression models. Endogenous OPN of Eca-109 and KYSE-510 were knocked down or overexpressed using small interfering RNAs. QRT-PCR, Western blot, flow cytometry, and CCK-8 were used to detect the function of Eca-109 and KYSE-510 cells. Tumor formation in nude mice was used to measure tumor growth after OPN inhibition.

Results

Eca-109 and KYSE-510 cells contain the si-OPN arrest cell cycle in the S-phase and increase apoptosis. These changes were OPN downregulation of the NF-κB pathway that significantly reduced the protein levels of TNF-α, IL-1β, and p-p65. However, the activity of Eca-109 and KYSE-510 cells was enhanced in OPN overexpressing cells. Then, the in vivo tumor formation experiment in nude mice showed that the tumor volume and weight of nude mice after silencing OPN were significantly reduced.

Conclusion

This study contributed to understanding the vital role of OPN in ESCC development and progression. This could be a promising molecular target for developing new ESCC diagnostic and therapeutic strategies.

Inorganic material based macrophage regulation for cancer therapy: basic concepts and recent advances

Macrophages with the M1 phenotype are a type of immune cell with exciting prospects for cancer therapy; however, when these macrophages infiltrate into tumours, many of them are induced by the tumour microenvironment to transform into the M2 type, which can enable tumour defence against external therapeutic strategies, assisting in tumour development. Macrophages have strong plasticity and functional heterogeneity, and their phenotypic transformation is complex and still poorly understood in relation to cancer therapy. Recent material advances in inorganic nanomaterials, especially inorganic elements in vivo, have accelerated the development of macrophage regulation-based cancer treatments. This review summarizes the basics of recent research on macrophage phenotype transformation and discusses the current challenges in macrophage type regulation. Then, the current achievements involving inorganic material-based macrophage regulation and the related anticancer effects of induced macrophages and their extracellular secretions are reviewed systematically. Importantly, inorganic nanomaterial-based macrophage phenotype regulation is flexible and can be adapted for different types of cancer therapies, presenting a possible novel approach for the generation of immune materials for cancer therapy.

Xmrks the Spot: Fish Models for Investigating Epidermal Growth Factor Receptor Signaling in Cancer Research

Studies conducted in several fish species, e.g., Xiphophorus hellerii (green swordtail) and Xiphophorus maculatus (southern platyfish) crosses, Oryzias latipes (medaka), and Danio rerio (zebrafish), have identified an oncogenic role for the receptor tyrosine kinase, Xmrk, a gene product closely related to the human epidermal growth factor receptor (EGFR), which is associated with a wide variety of pathological conditions, including cancer. Comparative analyses of Xmrk and EGFR signal transduction in melanoma have shown that both utilize STAT5 signaling to regulate apoptosis and cell proliferation, PI3K to modulate apoptosis, FAK to control migration, and the Ras/Raf/MEK/MAPK pathway to regulate cell survival, proliferation, and differentiation. Further, Xmrk and EGFR may also modulate similar chemokine, extracellular matrix, oxidative stress, and microRNA signaling pathways in melanoma. In hepatocellular carcinoma (HCC), Xmrk and EGFR signaling utilize STAT5 to regulate cell proliferation, and Xmrk may signal through PI3K and FasR to modulate apoptosis. At the same time, both activate the Ras/Raf/MEK/MAPK pathway to regulate cell proliferation and E-cadherin signaling. Xmrk models of melanoma have shown that inhibitors of PI3K and MEK have an anti-cancer effect, and in HCC, that the steroidal drug, adrenosterone, can prevent metastasis and recover E-cadherin expression, suggesting that fish Xmrk models can exploit similarities with EGFR signal transduction to identify and study new chemotherapeutic drugs.

JNK signaling as a target for anticancer therapy

The JNKs are members of mitogen-activated protein kinases (MAPK) which regulate many physiological processes including inflammatory responses, macrophages, cell proliferation, differentiation, survival, and death. It is increasingly clear that the continuous activation of JNKs has a role in cancer development and progression. Therefore, JNKs represent attractive oncogenic targets for cancer therapy using small molecule kinase inhibitors. Studies showed that the two major JNK proteins JNK1 and JNK2 have opposite functions in different types of cancers, which need more specification in the design of JNK inhibitors. Some of ATP- competitive and ATP non-competitive inhibitors have been developed and widely used in vitro, but this type of inhibitors lack selectivity and inhibits phosphorylation of all JNK substrates and may lead to cellular toxicity. In this review, we summarized and discussed the strategies of JNK binding inhibitors and the role of JNK signaling in the pathogenesis of different solid and hematological malignancies.

MAPK pathway and SIRT1 are involved in the down-regulation of secreted osteopontin expression by genistein in metastatic cancer cells

AIM

The regulation of secreted osteopontin (OPN) expression by genistein and its functional sequel in the metastatic cancer cells (MDA-MB-435 and MDA-MB-231) was ascertained.

MAIN METHODS

Western blot and Real-Time PCR were used to analyse the proteins and mRNA transcripts, respectively. Possible transcriptional regulation of secreted OPN was analyzed by chromatin immunoprecipitation assay, bioinformatics analysis, transfection and luciferase reporter assay. The specific siRNAs and constitutive p-ERKs were used to evaluate the role of the MAPK pathway. The functional sequel of genistein in these cells was analyzed by colony formation-, migration- and invasion- assay.

KEY FINDINGS

Secreted OPN expression was inhibited (up to ~0.7-fold) by genistein in these cells. Genistein (50 μM) displayed a reduction in the aggressiveness of these cells concerning colony formation rate, migration, and invasion. The p-ERK½ was increased by ~2.5-fold and ~1.5-fold upon 50 μM genistein and 15 μM resveratrol treatments at 24 h, respectively. Knockdown of ERK½ and PD98059, the inhibitor of MEK, promoted secreted OPN expression in vitro in these cells; while, the transfection of the constitutive active ERK2 (L73P and S151D) decreased the secreted OPN expression. Further, silent mating type information regulation 2 homolog 1 (SIRT1) expression in the cells was increased (~1.6-fold) upon genistein treatment (50 μM) likewise with resveratrol (~1.5-fold), an activator for SIRT1. Knockdown of SIRT1 increased OPN mRNA transcripts expression level and secreted OPN protein level in these cells.

SIGNIFICANCE

MAPK pathway and SIRT1 activation are involved in the regulation of secreted OPN by genistein in these cells.

Ketogenic Diet Elicits Antitumor Properties through Inducing Oxidative Stress, Inhibiting MMP-9 Expression, and Rebalancing M1/M2 Tumor-Associated Macrophage Phenotype in a Mouse Model of Colon Cancer

Many advanced cancers are characterized by metabolic disorders. A dietary therapeutic strategy was proposed to inhibit tumor growth through administration of low-carbohydrate, average-protein, and high-fat diet, which is also known as ketogenic diet (KD). In vivo antitumor efficacy of KD on transplanted CT26⁺ tumor cells in BALB/c mice was investigated. The results showed that the KD group had significantly higher blood β-hydroxybutyrate and lower blood glucose levels when compared with the normal diet group. Meanwhile, KD increased intratumor oxidative stress, and TUNEL staining showed KD-induced apoptosis against tumor cells. Interestingly, the distribution of CD16/32⁺ and iNOS⁺ M1 tumor-associated macrophages (TAMs) increased in the KD-treated group, with concomitantly less arginase-1⁺ M2 TAMs. Moreover, KD treatment downregulated the protein expression of matrix metalloproteinase-9 in CT26⁺ tumor-bearing mice. Western blot analysis demonstrated that the expression levels of HDAC3/PKM2/NF-κB 65/p-Stat3 proteins were reduced in the KD-treated group. Taken together, our results indicated that KD can prevent the progression of colon tumor via inducing intratumor oxidative stress, inhibiting the expression of the MMP-9, and enhancing M2 to M1 TAM polarization. A novel potential mechanism was identified that KD can prevent the progression of colon cancer by regulating the expression of HDAC3/PKM2/NF-κB65/p-Stat3 axis.

Functional Roles of Matrix Metalloproteinases and Their Inhibitors in Melanoma

The extracellular matrix (ECM) plays an important role in the regulation of the tissue microenvironment and in the maintenance of cellular homeostasis. Several proteins with a proteolytic activity toward several ECM components are involved in the regulation and remodeling of the ECM. Among these, Matrix Metalloproteinases (MMPs) are a class of peptidase able to remodel the ECM by favoring the tumor invasive processes. Of these peptidases, MMP-9 is the most involved in the development of cancer, including that of melanoma. Dysregulations of the MAPKs and PI3K/Akt signaling pathways can lead to an aberrant overexpression of MMP-9. Even ncRNAs are implicated in the aberrant production of MMP-9 protein, as well as other proteins responsible for the activation or inhibition of MMP-9, such as Osteopontin and Tissue Inhibitors of Metalloproteinases. Currently, there are different therapeutic approaches for melanoma, including targeted therapies and immunotherapies. However, no biomarkers are available for the prediction of the therapeutic response. In this context, several studies have tried to understand the diagnostic, prognostic and therapeutic potential of MMP-9 in melanoma patients by performing clinical trials with synthetic MMPs inhibitors. Therefore, MMP-9 may be considered a promising molecule for the management of melanoma patients due to its role as a biomarker and therapeutic target.

Effects of Aluminum on the Integrity of the Intestinal Epithelium: An in Vitro and in Vivo Study

BACKGROUND

Aluminum (Al) is the most abundant and ubiquitous metal in the environment. The main route of human exposure to Al is through food and water intake. Although human exposure to Al is common, the influence of Al on the gastrointestinal tract remains poorly understood.

OBJECTIVES

We aimed to further understand the toxic effect of Al and to elucidate the underlying cellular mechanisms in the intestinal barrier.

METHODS

The human intestinal epithelial cell line HT-29 and C57BL6 mice were exposed to AlCl3 at 0-16 mM (1-24h) and 5-50mg/kg body weight (13 weeks), respectively. In cell culture experiments, intracellular oxidative stress, inflammatory protein and gene expression, and intestinal epithelial permeability were measured. In animal studies, histological examination, gene expression, and myeloperoxidase (MPO) activity assays were conducted.

RESULTS

Cellular oxidative stress level (superoxide production) in AlCl3-treated cells (4 mM, 3h) was approximately 38-fold higher than that of the control. Both protein and mRNA expression of tight junction (TJ) components (occludin and claudin-1) in AlCl3-treated cells (1-4 mM, 24h) was significantly lower than that of the control. Transepithelial electrical resistance (TEER) decreased up to 67% in AlCl3-treated cells (2 mM, 24h) compared with that of the control, which decreased approximately 7%. Al activated extracellular signal-regulated kinase 1/2 and nuclear factor-kappa B (NF-κB), resulting in mRNA expression of matrix metalloproteinase-9, myosin light-chain kinase, and inflammatory cytokines [tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6] in HT-29 cells. Moreover, oral administration of AlCl3 to mice induced pathological alteration, MPO activation, and inflammatory cytokine (TNF-α, IL-1β, and IL-6) production in the colon.

CONCLUSION

Al induced epithelial barrier dysfunction and inflammation via generation of oxidative stress, down-regulation of the TJ proteins, and production of inflammatory cytokines in HT-29 cells. In addition, Al induced toxicity in the colon by increasing the levels of inflammatory cytokines and MPO activity and induced histological damage in a mouse model. Our data suggest that Al may be a potential risk factor for human intestinal diseases. https://doi.org/10.1289/EHP5701.

Functional interplay between NF-κB-inducing kinase and c-Abl kinases limits response to Aurora inhibitors in multiple myeloma

Considering that Aurora kinase inhibitors are currently under clinical investigation in hematologic cancers, the identification of molecular events that limit the response to such agents is essential for enhancing clinical outcomes. Here, we discover a NF-κB-inducing kinase (NIK)-c-Abl-STAT3 signaling-centered feedback loop that restrains the efficacy of Aurora inhibitors in multiple myeloma. Mechanistically, we demonstrate that Aurora inhibition promotes NIK protein stabilization via downregulation of its negative regulator TRAF2. Accumulated NIK converts c-Abl tyrosine kinase from a nuclear proapoptotic into a cytoplasmic antiapoptotic effector by inducing its phosphorylation at Thr735, Tyr245 and Tyr412 residues, and, by entering into a trimeric complex formation with c-Abl and STAT3, increases both the transcriptional activity of STAT3 and expression of the antiapoptotic STAT3 target genes PIM1 and PIM2. This consequently promotes cell survival and limits the response to Aurora inhibition. The functional disruption of any of the components of the trimer NIK-c-Abl-STAT3 or the PIM survival kinases consistently enhances the responsiveness of myeloma cells to Aurora inhibitors. Importantly, concurrent inhibition of NIK or c-Abl disrupts Aurora inhibitor-induced feedback activation of STAT3 and sensitizes myeloma cells to Aurora inhibitors, implicating a combined inhibition of Aurora and NIK or c-Abl kinases as potential therapies for multiple myeloma. Accordingly, pharmacological inhibition of c-Abl together with Aurora resulted in substantial cell death and tumor regression in vivo The findings reveal an important functional interaction between NIK, Abl and Aurora kinases, and identify the NIK, c-Abl and PIM survival kinases as potential pharmacological targets for improving the efficacy of Aurora inhibitors in myeloma.

Osteopontin as a marker of vasculopathy in pediatric patients with type 1 diabetes mellitus: Relation to vascular structure

BACKGROUND

Type 1 diabetes mellitus (T1DM) is associated with serious micro-vascular and macro-vascular complications. Osteopontin (OPN) has emerged as a strong predictor of incipient diabetic nephropathy and a first-ever cardiovascular event in adults with T1DM. OPN is linked to coronary atherosclerosis in type 2 diabetes. The aim of the study was to test the hypothesis that OPN could be a potential marker for micro-vascular complications in children and adolescents with T1DM and we assessed its relation to carotid and aortic intima media thickness (CIMT and AIMT) as non-invasive index for subclinical atherosclerosis.

METHODS

Eighty patients with T1DM ≤18 years were divided into 2 groups according to the presence of micro-vascular complications and compared with 40 age- and sex-matched healthy controls. Fasting blood glucose, high sensitivity C-reactive protein (hs-CRP), HbA1c, urinary albumin creatinine ratio (UACR), OPN, CIMT, and AIMT were assessed.

RESULTS

Both CIMT and AIMT were significantly higher in patients with and without micro-vascular complications compared with healthy controls (P < .001). OPN concentrations were significantly elevated in all diabetic patients compared with controls (P = .002). OPN was also significantly higher in patients with micro-vascular complications than patients without (P < .001) but levels were comparable among those without complications and controls (P = .322). Receiver operating characteristic curve analysis revealed that OPN cut-off value 90 ng/mL could differentiate patients with and without micro-vascular complications with 81.7% sensitivity and 95.8% specificity. Significant positive correlations were found between OPN and HbA1c, UACR, CIMT, and AIMT.

CONCLUSIONS

OPN could be considered a marker of vasculopathy and subclinical atherosclerosis in pediatric T1DM.

Osteopontin-a splice variant is overexpressed in papillary thyroid carcinoma and modulates invasive behavior

Osteopontin (OPN) is a matricellular protein overexpressed in cancer cells and modulates tumorigenesis and metastasis, including in thyroid cancer (TC). The contribution of each OPN splice variant (OPN-SV), named OPNa, OPNb and OPNc, in TC is currently unknown. This study evaluates the expression of total OPN (tOPN) and OPN-SV in TC tissues and cell lines, their correlation with clinicopathological, molecular features and their functional roles. We showed that tOPN and OPNa are overexpressed in classic papillary thyroid carcinoma (cPTC) in relation to adjacent thyroid, adenoma and follicular variant of papillary thyroid carcinoma (fvPTC) tissues. In cPTC, OPNa overexpression is associated with larger tumor size, vascular invasion, extrathyroid extension and BRAF^V600E mutation. We found that TC cell lines overexpressing OPNa exhibited increased proliferation, migration, motility and in vivo invasion. Conditioned medium secreted from cells overexpressing OPNa induce MMP2 and MMP9 metalloproteinases activity. In summary, we described the expression pattern of OPN-SV in cPTC samples and the key role of OPNa expression on activating TC tumor progression features. Our findings highlight OPNa variant as TC biomarker, besides being a putative target for cPTC therapeutic approaches.

Cancer-associated Fibroblast-derived IL-6 Promotes Head and Neck Cancer Progression via the Osteopontin-NF-kappa B Signaling Pathway

Osteopontin (OPN), a chemokine-like protein, plays a crucial role in the proliferation and metastasis of various cancers. However, how tumor stroma modulates the expression of neoplastic OPN and the multifaceted roles of OPN in head and neck cancer (HNC) are unclear. In this study, we tried to investigate the bridging role of OPN between tumor stroma and cancer cells.

Methods: Immunohistochemical staining and quantitative real-time PCR were used to detect OPN expression in HNC tissues, and the correlations between OPN expression and clinicopathologic features were then analyzed. We used a co-culture assay to study the modulatory role of IL-6 on OPN expression and immunoprecipitation analysis was used to determine the endogenous interaction between OPN and integrin αvβ3. Furthermore, a xenograft assay was carried out to confirm the tumor-promoting role and the potential therapeutic value of OPN in HNC.

Results: We found that OPN was significantly up-regulated in HNCs, and the elevated OPN was correlated with poor prognosis. Moreover, we identified IL-6 secreted by cancer-associated fibroblasts (CAFs) as the major upstream molecule that triggers the induction of neoplastic OPN. As such, during the interaction of fibroblasts and cancer cells, the increased neoplastic OPN induced by stromal IL-6 accelerated the growth, migration and invasion of cancer cells. More importantly, we also showed that soluble OPN could promote HNC progression via the integrin αvβ3-NF-kappa B pathway, and the combination of OPN and IL-6 had a better prognostic and diagnostic performance in HNC than either molecule alone.

Conclusion: Our study identified a novel modulatory role for OPN in HNC progression and further demonstrated that the combination of OPN and IL-6 might be a promising prognostic and diagnostic indicator as well as a potential cancer therapeutic target.

Osteopontin is a multi-faceted pro-tumorigenic driver for central nervous system lymphoma

Osteopontin (OPN) is the most upregulated gene in primary central nervous system lymphoma (PCNSL) compared to non-CNS diffuse large B cell lymphoma (DLBCL). We show here that OPN is a key mediator of intracerebral tumor growth, invasion, and dissemination in CNS lymphoma, and that these effects depend upon activation of NF-κB. We further show that activation of NF-κB by OPN occurs through a unique mechanism in which intracellular OPN (iOPN) causes transcriptional downregulation of the NF-κB inhibitors, A20/TNFAIP3 and ABIN1/TNIP1, and secretory OPN (sOPN) promotes receptor-mediated activation of NF-κB. We also identify NF-κB-mediated induction of matrix metalloproteinase-8 (MMP-8) as a specific feature of OPN-mediated tissue invasion. These results implicate OPN as a candidate for development of targeted therapy for patients with PCNSL.

MMP-9 overexpression is associated with intragenic hypermethylation of MMP9 gene in melanoma

Tumor spreading is associated with the degradation of extracellular matrix proteins, mediated by the overexpression of matrix metalloproteinase 9 (MMP-9). Although, such overexpression was linked to epigenetic promoter methylation, the role of intragenic methylation was not clarified yet. Melanoma was used as tumor model to investigate the relationship between the DNA intragenic methylation of MMP9 gene and MMP-9 overexpression at transcriptional and protein levels. Computational analysis revealed DNA hypermethylation within the intragenic CpG-2 region of MMP9 gene in melanoma samples with high MMP-9 transcript levels. In vitro validation showed that CpG-2 hotspot region was hypermethylated in the A375 melanoma cell line with highest mRNA and protein levels of MMP-9, while low methylation levels were observed in the MEWO cell line where MMP-9 was undetectable. Concordant results were demonstrated in both A2058 and M14 cell lines. This correlation may give further insights on the role of MMP-9 upregulation in melanoma.

Activin promotes skin carcinogenesis by attraction and reprogramming of macrophages

Activin has emerged as an important player in different types of cancer, but the underlying mechanisms are largely unknown. We show here that activin overexpression is an early event in murine and human skin tumorigenesis. This is functionally important, since activin promoted skin tumorigenesis in mice induced by the human papillomavirus 8 oncogenes. This was accompanied by depletion of epidermal γδ T cells and accumulation of regulatory T cells. Most importantly, activin increased the number of skin macrophages via attraction of blood monocytes, which was prevented by depletion of CCR2‐positive monocytes. Gene expression profiling of macrophages from pre‐tumorigenic skin and bioinformatics analysis demonstrated that activin induces a gene expression pattern in skin macrophages that resembles the phenotype of tumor‐associated macrophages in different malignancies, thereby promoting angiogenesis, cell migration and proteolysis. The functional relevance of this finding was demonstrated by antibody‐mediated depletion of macrophages, which strongly suppressed activin‐induced skin tumor formation. These results demonstrate that activin induces skin carcinogenesis via attraction and reprogramming of macrophages and identify novel activin targets involved in tumor formation.

Impacts of Cross-Linkers on Biological Effects of Mesoporous Silica Nanoparticles

Chemically synthesized cross-linkers play decisive roles in variable cargos attached to nanoparticles (NPs). Previous studies reported that surface properties, such as the size, charge, and surface chemistry, are particularly important determinants influencing the biological fate and actions of NPs and cells. Recent studies also focused on the relationship of serum proteins with the surface properties of NPs (also called the protein corona), which is recognized as a key factor in determining the cytotoxicity and biodistribution. However, there is concern that cross-linkers conjugated onto NPs might induce undesirable biological effects. Cell responses induced by cross-linkers have not yet been precisely elucidated. Herein, using mesoporous silica nanoparticles (MSNs) the surfaces of which were separately conjugated with four popular heterobifunctional cross-linkers, i.e., N-[α-maleimidoacetoxy]succinimide ester (AMAS), m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), and maleimide poly(ethylene glycol) succinimidyl carboxymethyl ester (MAL-PEG-SCM), we investigated cross-linker-conjugated MSNs to determine whether they can cause cytotoxicity, or enhance reactive oxygen species (ROS) generation, nuclear factor (NF)-κB activation, and p-p38 or p21 protein expressions in RAW264.7 macrophage cells. Furthermore, we also separately conjugated two biomolecules containing TAT peptides and bovine serum albumin (BSA) as model systems to study their cell responses in detail. Finally, in vivo mice studies evaluated the biodistribution and blood assays (biochemistry and complete blood count) of PEG-derivative NPs, and results suggested that TAT peptides caused significant white blood cell (WBC)-related cell and platelet abnormalities, as well as liver and kidney dysfunction compared to BSA when conjugated onto MSNs. The results showed that attention to cross-linkers should be considered an issue in the surface modification of NPs. We anticipate that our results could be helpful in developing biosafety nanomaterials.

Substrate-zymography: a still worthwhile method for gelatinases analysis in biological samples

Matrix metallo-proteinases (MMPs) are a family of zinc-dependent endopeptidases, capable of degrading all the molecular components of extracellular matrix. A class of MMPs is gelatinases which includes gelatinase A or MMP-2 (72 kDa) and gelatinase B or MMP-9 (92 kDa), which have been shown to play critical roles in pathophysiology of many human disease and, in particular, cancer progression. For these reasons they obtained a great interest as potential non-invasive biomarker in providing useful clinical information in cancer diagnosis and therapy. A sensitive and unexpensive method for analysis of gelatinases is the gelatine zymography, which allows to measure the relative amounts of active and inactive enzymes in body fluids and tissue extracts. The procedure involves the electrophoretic separation of proteins under denaturing but non reducing conditions through a polyacrylamide gel containing a synthetic substrate (gelatin). The aim of this mini-review has been to describe the general principles of gelatine zymography technique, underling the main advantages and disadvantages. Even though an improvement of this method is necessary for a better applicability in laboratory medicine, gelatine zymography represents the most convenient method to detect the activity of the different gelatinases from a wide range of biological samples.

NF‑κB inhibition is associated with OPN/MMP‑9 downregulation in cutaneous melanoma

The development of cutaneous melanoma is influenced by genetic factors, including BRAF mutations and environmental factors, such as ultraviolet exposure. Its progression has been also associated with the involvement of several tumour microenvironmental molecules. Among these, nuclear factor‑κB (NF‑κB) has been indicated as a key player of osteopontin (OPN) and matrix metalloproteinase‑9 (MMP‑9) activation. However, whether NF‑κB plays a role in the development and progression of melanoma in association with the OPN/MMP‑9 axis according to the BRAFV600E mutation status has not been investigated in detail to date. Thus, in the present study, in order to shed light on this matter, 148 patients with melanoma and 53 healthy donors were recruited for the analysis of OPN, MMP‑9 and NF‑κB. Significantly higher circulating levels of OPN and MMP‑9 were observed in the patients with melanoma when compared to the healthy donors. Similar data were obtained for NF‑κB p65 activity. The OPN levels did not differ significantly between melanomas with or without BRAFV600E mutation. However, as regards NF‑κB and MMP‑9, significant differences were observed between the melanomas with or without BRAFV600E mutation. To determine whether NF‑κB inhibition is associated with a decrease in the levels of OPN and MMP‑9, peripheral blood mononuclear cells from 29 patients with melanoma were treated with the NF‑κB inhibitor, dehydroxymethylepoxyquinomycin (DHMEQ), with or without OPN. As expected, the inhibition of NF‑κB induced a marked decrease in both the OPN and MMP‑9 levels. Furthermore, the decrease in MMP‑9 levels was higher among melanomas harbouring the BRAFV600E mutation. Overall, our data suggest that the activation of MMP‑9 is associated with the BRAFV600E mutation status. Furthermore, such an activation is mediated by NF‑κB, suggesting its role as therapeutic target in patients with melanoma.

Phenotype-Genotype Association Analysis of ACTH-Secreting Pituitary Adenoma and Its Molecular Link to Patient Osteoporosis

Adrenocorticotrophin (ACTH)-secreting pituitary adenoma, also known as Cushing disease (CD), is rare and causes metabolic syndrome, cardiovascular disease and osteoporosis due to hypercortisolism. However, the molecular pathogenesis of CD is still unclear because of a lack of human cell lines and animal models. Here, we study 106 clinical characteristics and gene expression changes from 118 patients, the largest cohort of CD in a single-center. RNA deep sequencing is used to examine genotypic changes in nine paired female ACTH-secreting pituitary adenomas and adjacent nontumorous pituitary tissues (ANPT). We develop a novel analysis linking disease clinical characteristics and whole transcriptomic changes, using Pearson Correlation Coefficient to discover a molecular network mechanism. We report that osteoporosis is distinguished from the phenotype and genotype analysis. A cluster of genes involved in osteoporosis is identified using Pearson correlation coefficient analysis. Most of the genes are reported in the bone related literature, confirming the feasibility of phenotype-genotype association analysis, which could be used in the analysis of almost all diseases. Secreted phosphoprotein 1 (SPP1), collagen type I α 1 chain (COL1A1), 5′-nucleotidase ecto (NT5E), HtrA serine peptidase 1 (HTRA1) and angiopoietin 1 (ANGPT1) and their signalling pathways are shown to be involved in osteoporosis in CD patients. Our discoveries provide a molecular link for osteoporosis in CD patients, and may open new potential avenues for osteoporosis intervention and treatment.

Clinical Significance of Circulating Osteopontin Levels in Patients With Lung Cancer and Correlation With VEGF and MMP-9

Osteopontin (OPN) is a multifunctional cytokine involved in carcinogenesis. Serum levels of OPN, vascular endothelial growth factor (VEGF), and matrix metalloproteinase-9 (MMP-9) were measured by ELISA in 90 lung cancer patients. OPN levels were elevated in patients compared to controls (p <.0001). Smokers, patients with worse performance status, and weight loss exhibited higher OPN levels (p =.0012,.00036, and.0003, respectively). Increased OPN levels were associated with worse survival (p =.0018). Finally, OPN levels were positively correlated with both VEGF (p =.0008) and MMP-9 (p <.0001). OPN might serve as a prognostic biomarker, and the positive correlation between OPN and both VEGF and MMP-9 could implicate new insights in tumor angiogenesis.

Inhibition of nuclear factor-kappa B enhances the tumor growth of ovarian cancer cell line derived from a low-grade papillary serous carcinoma in p53-independent pathway

Background

NF-kB can function as an oncogene or tumor suppressor depending on cancer types. The role of NF-kB in low-grade serous ovarian cancer, however, has never been tested. We sought to elucidate the function of NF-kB in the low-grade serous ovarian cancer.

Methods

The ovarian cancer cell line, HOC-7, derived from a low-grade papillary serous carcinoma. Introduction of a dominant negative mutant, IkBαM, which resulted in decrease of NF-kB function in ovarian cancer cell lines. The transcription ability, tumorigenesis, cell proliferation and apoptosis were observed in derivative cell lines in comparison with parental cells.

Results

Western blot analysis indicated increased expression of the anti-apoptotic proteins Bcl-xL and reduced expression of the pro-apoptotic proteins Bax, Bad, and Bid in HOC-7/IĸBαM cell. Further investigations validate this conclusion in KRAS wildtype cell line SKOV3. Interesting, NF-kB can exert its pro-apoptotic effect by activating mitogen-activated protein kinase (MAPK) phosphorylation in SKOV3 ovarian cancer cell, whereas opposite changes detected in p-MEK in HOC-7 ovarian cancer cell, the same as some chemoresistant ovarian cancer cell lines. In vivo animal assay performed on BALB/athymic mice showed that injection of HOC-7 induced subcutaneous tumor growth, which was completely regressed within 7 weeks. In comparison, HOC-7/IĸBαM cells caused sustained tumor growth and abrogated tumor regression, suggesting that knock-down of NF-kB by IĸBαM promoted sustained tumor growth and delayed tumor regression in HOC-7 cells.

Conclusion

Our results demonstrated that NF-kB may function as a tumor suppressor by facilitating regression of low grade ovarian serous carcinoma through activating pro-apoptotic pathways.

Selective Expression of Osteopontin in ALS-resistant Motor Neurons is a Critical Determinant of Late Phase Neurodegeneration Mediated by Matrix Metalloproteinase-9

Differential vulnerability among motor neuron (MN) subtypes is a fundamental feature of amyotrophic lateral sclerosis (ALS): fast-fatigable (FF) MNs are more vulnerable than fast fatigue-resistant (FR) or slow (S) MNs. The reason for this selective vulnerability remains enigmatic. We report here that the extracellular matrix (ECM) protein osteopontin (OPN) is selectively expressed by FR and S MNs and ALS-resistant motor pools, whereas matrix metalloproteinase-9 (MMP-9) is selectively expressed by FF MNs. OPN is secreted and accumulated as extracellular granules in ECM in three ALS mouse models and a human ALS patient. In SOD1(G93A) mice, OPN/MMP-9 double positivity marks remodeled FR and S MNs destined to compensate for lost FF MNs before ultimately dying. Genetic ablation of OPN in SOD1(G93A) mice delayed disease onset but then accelerated disease progression. OPN induced MMP-9 up-regulation via αvβ3 integrin in ChAT-expressing Neuro2a cells, and also induced CD44-mediated astrocyte migration and microglial phagocytosis in a non-cell-autonomous manner. Our results demonstrate that OPN expressed by FR/S MNs is involved in the second-wave neurodegeneration by up-regulating MMP-9 through αvβ3 integrin in the mouse model of ALS. The differences in OPN/MMP-9 expression profiles in MN subsets partially explain the selective MN vulnerability in ALS.

Osteopontin promotes a cancer stem cell-like phenotype in hepatocellular carcinoma cells via an integrin-NF-κB-HIF-1α pathway

There is increasing evidence to suggest that hepatocellular carcinomas (HCCs) are sustained by a distinct subpopulation of self-renewing cells known as cancer stem cells. However, the precise signals required for maintenance of stemness-like properties of these cells are yet to be elucidated. Here, we demonstrated that the level of oncoprotein osteopontin (OPN) in tumor cells of the edge of bulk tumors was significantly correlated with the clinical prognosis of patients with HCC. OPN was highly expressed in side population fractions of HCC cell lines, as well as in dormant cells, spheroids and chemo-resistant cancer cells, all of which are considered as having stemness-like cellular features. Depletion of OPN in HCC cell lines resulted in a reduction in the proportion of side population fractions, formation of hepato-spheroids, expression of stem-cell-associated genes and decreased tumorigenecity in immunodeficient mice. Mechanistically, OPN was demonstrated to bind to integrin α_vβ₃ and activate the transcription factor NF-κB, which resulted in upregulation of HIF-1α transcription and its downstream gene, BMI1, to mediate maintenance of the stemness-like phenotype. Suppression of the α_vβ₃–NF-κB–HIF-1α pathway decreased OPN-mediated self-renewal capabilities. Levels of OPN protein expression were significantly correlated with HIF-1α protein levels in HCC tumor tissue samples. OPN might promote a cancer stem cell-like phenotype via the α_vβ₃–NF-κB–HIF-1α pathway. Our findings offer strong support for OPN requirement in maintaining stem-like properties in HCC cells.

A polymeric nanoparticle formulation of curcumin in combination with sorafenib synergistically inhibits tumor growth and metastasis in an orthotopic model of human hepatocellular carcinoma

Curcumin, a yellow polyphenol extracted from the rhizome of turmeric root (Curcuma longa) has potent anti-cancer properties in many types of tumors with ability to reverse multidrug resistance of cancer cells. However, widespread clinical application of this agent in cancer and other diseases has been limited due to its poor aqueous solubility. The recent findings of polymeric nanoparticle formulation of curcumin (NFC) have shown the potential for circumventing the problem of poor solubility, however evidences for NFC's anti-cancer and reverse multidrug resistance properties are lacking. Here we provide models of human hepatocellular carcinoma (HCC), the most common form of primary liver cancer, in vitro and in vivo to evaluate the efficacy of NFC alone and in combination with sorafenib, a kinase inhibitor approved for treatment of HCC. Results showed that NFC not only inhibited the proliferation and invasion of HCC cell lines in vitro, but also drastically suppressed primary tumor growth and lung metastases in vivo. Moreover, in combination with sorafenib, NFC induced HCC cell apoptosis and cell cycle arrest. Mechanistically, NFC and sorafenib synergistically down-regulated the expression of MMP9 via NF-κB/p65 signaling pathway. Furthermore, the combination therapy significantly decreased the population of CD133-positive HCC cells, which have been reported as cancer initiating cells in HCC. Taken together, NanoCurcumin provides an opportunity to expand the clinical repertoire of this agent. Additional studies utilizing a combination of NanoCurcumin and sorafenib in HCC are needed for further clinical development.

Tumor microenvironment in diffuse large B-cell lymphoma: Matrixmetalloproteinases activation is mediated by osteopontin overexpression

Non-Hodgkin lymphomas (NHL) are a heterogeneous group of lymphoproliferative malignancies with variable patterns of behavior and responses to therapy. NHL development and invasion depend on multiple interactions between tumor cells and non-neoplastic cells. Such interactions are usually modulated by several cytokines. Accordingly, it was demonstrated that matrix-metalloproteinase (MMP)-2 and MMP-9 were activated in human lymphoid cell lines by interleukin-6 (IL-6). The activation of these enzymes is associated with tumor invasion and metastasis in human cancers. MMPs are also activated in several cancers by osteopontin (OPN), a secreted glycoprotein that regulates cell adhesion, migration, and survival. However, it is still unclear if MMPs play a role in NHL development and if their activation is determined by OPN and/or IL-6. In the present study, two groups of 78 NHL patients and 95 healthy donors were recruited for the analysis of OPN, MMP-2, MMP-9 and IL-6.Significant higher circulating levels of MMP-2, MMP-9, OPN and IL-6 were observed in NHL patients when compared to healthy donors. Similar data were obtained by analyzing the activity of both MMP-2 and MMP-9. The multivariate regression model indicates that, in both NHL cases and healthy donors, OPN is associated with the increase of MMP-2 and MMP-9 levels independently of IL-6. These data were first confirmed by “in silico” analyses and then by “in vitro” experiments conducted on peripheral blood mononuclear cells randomly selected from both NHL patients and healthy donors.Overall, our data suggest that the activation of MMPs in NHL development is mostly associated with OPN. However, IL-6 may play an important role in the lymphomagenesis through the activation of other molecular pathways. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis, Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza.

Osteopontin is indispensible for AP1-mediated angiotensin II-related miR-21 transcription during cardiac fibrosis

Aims

Osteopontin (OPN) is a multifunctional cytokine critically involved in cardiac fibrosis. However, the underlying mechanisms are unresolved. Non-coding RNAs are powerful regulators of gene expression and thus might mediate this process.

Methods and results

OPN and miR-21 were significantly increased in cardiac biopsies of patients with myocardial fibrosis. Ang II infusion via osmotic minipumps led to specific miRNA regulations with miR-21 being strongly induced in wild-type (WT) but not OPN knockout (KO) mice. This was associated with enhanced cardiac collagen content, myofibroblast activation, ERK-MAP kinase as well as AKT signalling pathway activation and a reduced expression of Phosphatase and Tensin Homologue (PTEN) as well as SMAD7 in WT but not OPN KO mice. In contrast, cardiotropic AAV9-mediated overexpression of OPN in vivo further enhanced cardiac fibrosis. In vitro, Ang II induced expression of miR-21 in WT cardiac fibroblasts, while miR-21 levels were unchanged in OPN KO fibroblasts. As pri-miR-21 was also increased by Ang II, we studied potential involved upstream regulators; Electrophoretic Mobility Shift and Chromatin Immunoprecipitation analyses confirmed activation of the miR-21 upstream-transcription factor AP-1 by Ang II. Recombinant OPN directly activated miR-21, enhanced fibrosis, and activated the phosphoinositide 3-kinase pathway. Locked nucleic acid-mediated miR-21 silencing ameliorated cardiac fibrosis development in vivo.

Conclusion

In cardiac fibrosis related to Ang II, miR-21 is transcriptionally activated and targets PTEN/SMAD7 resulting in increased fibroblast survival. OPN KO animals are protected from miR-21 increase and fibrosis development due to impaired AP-1 activation and fibroblast activation.

Osteopontin (OPN) is a pleiotropic cytokine, which has been shown to be a pivotal factor in myofibroblast activation in cardiac fibrosis, thereby acting as a strong driver of heart failure development in humans. MicroRNAs (miRNAs) are under intense investigation as powerful regulators of various diseases. First phase I and II clinical trials using miRNA inhibitors have been initiated. We here show, that OPN is essential in the activation of AP-1 and subsequent transcription of miR-21 in cardiac fibrosis related to Ang II. OPN null mice are protected from miR-21 increase and fibrosis development due to impaired AP-1 activation and fibroblast activation. In the future, these findings may result in miRNA therapeutic approaches to treat patients with cardiac remodelling, in which levels of OPN and miR-21 are increased.

Role of osteopontin in the regulation of human bladder cancer proliferation and migration in T24 cells

Osteopontin (OPN), a secreted acid glycoprotein with a variety of functions, promotes tumor proliferation, differentiation, invasion and metastasis. The aim of the current study was to investigate whether OPN may serve as a potential therapeutic target for human bladder cancer. RNA interference (RNAi) was performed to downregulate the expression of the OPN gene in T24 human bladder cancer cells. The mRNA and protein expression levels of OPN following RNAi were determined using reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. In addition, the cell cycle progression, apoptosis and proliferation were investigated using by flow cytometric analysis and MTT assay. The cell invasion ability was measured using a Matrigel transwell assay. The mRNA and protein expression levels of OPN were found to be significantly downregulated following RNAi. The proliferation and invasion of T24 cells were significantly inhibited in vitro. In conclusion, RNAi‑targeting OPN may inhibit the proliferation, invasion and tumorigenicity of human bladder cancer cells. Therefore, OPN may serve as a potential therapeutic target for human bladder cancer.

α-Solanine inhibits invasion of human prostate cancer cell by suppressing epithelial-mesenchymal transition and MMPs expression

α-Solanine, a naturally occurring steroidal glycoalkaloid found in nightshade (Solanum nigrum Linn.), was found to inhibit proliferation and induce apoptosis of tumor cells. However, the mechanism involved in suppression of cancer cell metastasis by α-solanine remains unclear. This study investigates the suppression mechanism of α-solanine on motility of the human prostate cancer cell PC-3. Results show that α-solanine reduces the viability of PC-3 cells. When treated with non-toxic doses of α-solanine, cell invasion is markedly suppressed by α-solanine. α-Solanine also significantly elevates epithelial marker E-cadherin expression, while it concomitantly decreases mesenchymal marker vimentin expression, suggesting it suppresses epithelial-mesenchymal transition (EMT). α-Solanine reduces the mRNA level of matrix metalloproteinase-2 (MMP-2), MMP-9 and extracellular inducer of matrix metalloproteinase (EMMPRIN), but increases the expression of reversion-inducing cysteine-rich protein with kazal motifs (RECK), and tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2. Immunoblotting assays indicate α-solanine is effective in suppressing the phosphorylation of phosphatidylinositide-3 kinase (PI3K), Akt and ERK. Moreover, α-solanine downregulates oncogenic microRNA-21 (miR-21) and upregulates tumor suppressor miR-138 expression. Taken together, the results suggest that inhibition of PC-3 cell invasion by α-solanine may be, at least in part, through blocking EMT and MMPs expression. α-Solanine also reduces ERK and PI3K/Akt signaling pathways and regulates expression of miR-21 and miR-138. These findings suggest an attractive therapeutic potential of α-solanine for suppressing invasion of prostate cancer cell.

Osteoponin promoter controlled by DNA methylation: aberrant methylation in cloned porcine genome

Cloned animals usually exhibited many defects in physical characteristics or aberrant epigenetic reprogramming, especially in some important organ development. Osteoponin (OPN) is an extracellular-matrix protein involved in heart and bone development and diseases. In this study, we investigated the correlation between OPN mRNA and its promoter methylation changes by the 5-aza-dc treatment in fibroblast cell and promoter assay. Aberrant methylation of porcine OPN was frequently found in different tissues of somatic nuclear transferred cloning pigs, and bisulfite sequence data suggested that the OPN promoter region −2615 to −2239 nucleotides (nt) may be a crucial regulation DNA element. In pig ear fibroblast cell culture study, the demethylation of OPN promoter was found in dose-dependent response of 5-aza-dc treatment and followed the OPN mRNA reexpression. In cloned pig study, discrepant expression pattern was identified in several cloned pig tissues, especially in brain, heart, and ear. Promoter assay data revealed that four methylated CpG sites presenting in the −2615 to −2239 nt region cause significant downregulation of OPN promoter activity. These data suggested that methylation in the OPN promoter plays a crucial role in the regulation of OPN expression that we found in cloned pigs genome.

Osteopontin promotes the progression of gastric cancer through the NF-κB pathway regulated by the MAPK and PI3K

To elucidate the biological functions of osteopontin (OPN) in gastric tumors and to better understand the molecular events of OPN responsible for the malignancy, the present studies were performed. Growth curve, apoptosis assay, invasion assay and migration assay revealed that OPN status significantly affected proliferation, apoptosis, invasion and migration in gastric cancer cell lines. In mouse xenograft models of human gastric cancer, OPN silencing significantly inhibited tumor growth and the incidence of metastasis compared with non-silenced control. Mechanistic investigations revealed that OPN silencing inhibited the mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K) and phosphoinositide 3-kinase (NF-κB) pathways, and OPN-mediated NF-κB activity was reduced in the presence of MAPK or PI3K inhibitor. Our findings also indicated that OPN through the NF-κB pathway promotes the expression of matrix metalloproteinase 2 (MMP-2), MMP-9 and urokinase-type plasminogen activator (uPA), the activation of MMP-2 and MMP-9, and the inhibition of caspase-3. Taken together, our results reveal that OPN promotes the progression of gastric cancer through the NF-κB pathway, which is regulated by the MAPK and PI3K pathways and leads to MMP-2, MMP-9 and uPA activation and caspase-3 inhibition. These findings identify OPN as a novel oncogene in gastric cancer and suggest that OPN is an attractive therapeutic target for this aggressive malignancy.

Role of osteopontin in the pathophysiology of cancer

Osteopontin (OPN) is a multifunctional cytokine that impacts cell proliferation, survival, drug resistance, invasion, and stem like behavior. Due to its critical involvement in regulating cellular functions, its aberrant expression and/or splicing is functionally responsible for undesirable alterations in disease pathologies, specifically cancer. It is implicated in promoting invasive and metastatic progression of many carcinomas. Due to its autocrine and paracrine activities OPN has been shown to be a crucial mediator of cellular cross talk and an influential factor in the tumor microenvironment. OPN has been implicated as a prognostic and diagnostic marker for several cancer types. It has also been explored as a possible target for treatment. In this article we hope to provide a broad perspective on the importance of OPN in the pathophysiology of cancer.

Matrix metalloproteinase-9: Many shades of function in cardiovascular disease

Matrix metalloproteinase (MMP)-9, one of the most widely investigated MMPs, regulates pathological remodeling processes that involve inflammation and fibrosis in cardiovascular disease. MMP-9 directly degrades extracellular matrix (ECM) proteins and activates cytokines and chemokines to regulate tissue remodeling. MMP-9 deletion or inhibition has proven overall beneficial in multiple animal models of cardiovascular disease. As such, MMP-9 expression and activity is a common end point measured. MMP-9 cell-specific overexpression, however, has also proven beneficial and highlights the fact that little information is available on the underlying mechanisms of MMP-9 function. In this review, we summarize our current understanding of MMP-9 physiology, including structure, regulation, activation, and downstream effects of increased MMP-9. We discuss MMP-9 roles during inflammation and fibrosis in cardiovascular disease. By concentrating on the substrates of MMP-9 and their roles in cardiovascular disease, we explore the overall function and discuss future directions on the translational potential of MMP-9 based therapies.

Deep sequence analysis of gene expression identifies osteopontin as a downstream effector of integrin-linked kinase (ILK) in cardiac-specific ILK knockout mice

BACKGROUND

Integrin-linked kinase (ILK) is a serine/threonine kinase that has been linked to human and experimental heart failure, but its role in the heart is not fully understood.

METHODS AND RESULTS

To define the role of cardiomyocyte ILK, we generated cardiac-specific ILK knockout mice using α-myosin heavy chain-driven Cre expression. Cardiac-specific ILK knockout mice spontaneously developed lethal dilated cardiomyopathy and heart failure with an early increase in apoptosis, fibrosis, and cardiac inflammation. To identify downstream effectors, we used deep sequence analysis of gene expression to compare comprehensive transcriptional profiles of cardiac-specific ILK knockout and wild-type hearts from 10-day-old mice before the development of cardiac dysfunction. Approximately 2×10(6) cDNA clones from each genotype were sequenced, corresponding to 33 274 independent transcripts. A total of 93 genes were altered, using nominal thresholds of >1.4-fold change and P<0.001. The most highly upregulated gene was osteopontin (47-fold increase; P=9.6×10(-45)), an inflammatory chemokine implicated in heart failure pathophysiology. ILK also regulated osteopontin expression in cardiomyocytes in vitro. Importantly, blocking antibodies to osteopontin mitigated but did not fully rescue the functional decline in cardiac-specific ILK knockout mice.

CONCLUSIONS

Cardiomyocyte-specific ILK deletion leads to a lethal cardiomyopathy characterized by cardiomyocyte death, fibrosis, and inflammation. Comprehensive profiling identifies ILK-dependent transcriptional effects and implicates osteopontin as a contributor to these phenotypes.

A novel compound RY10-4 induces apoptosis and inhibits invasion via inhibiting STAT3 through ERK-, p38-dependent pathways in human lung adenocarcinoma A549 cells

Previous reports suggested that protoapigenone showed remarkable antitumor activities against a broad spectrum of human cancer cell lines, but had no effect on human lung adenocarcinoma A549 cell. The lack of effective remedies had necessitated the application of new therapeutic scheme. A novel compound RY10-4 which has the similar structure close to protoapigenone showed better antitumor activity. Treatment with RY10-4 inhibited the expression of pro-caspase-3, pro-caspase-9, Bcl-2 as well as phosphorylation of signal transducer and activator of transcription-3 (p-STAT3). It also reduced the expressions of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and increases the expressions of reversion-inducing cysteine-rich protein with kazal motifs (RECK), as well as tissue inhibitor of metalloproteinase (TIMP) via inhibiting STAT3 by activating the mitogen-activated protein (MAP) kinases (the c-Jun N-terminal kinase (JNK), the p38 and extracellular signal-regulated kinase (ERK)) in A549 cells treated with RY10-4. Moreover, the cytotoxic effect of RY10-4 was induction of apoptosis in A549 cells by enhancing production of reactive oxygen species (ROS). Taken together, the observations suggested that RY10-4 had affected Bcl-2 family members, caspases, MMPs, TIMPs expressions and ROS production via inhibiting STAT3 activities through ERK and p38 pathways in A549 cells.

MACC1 is involved in the regulation of proliferation, colony formation, invasion ability, cell cycle distribution, apoptosis and tumorigenicity by altering Akt signaling pathway in human osteosarcoma

There is mounting evidence that metastasis-associated in colon cancer-1 (MACC1) plays pivotal roles in development and progression of many tumors, particularly in osteosarcoma (OS). However, its precise roles and molecular mechanisms remain to be delineated in OS. In the current study, we found that the levels of MACC1 mRNA and protein in four OS cell lines (MG-63, HOS, SaOS-2 and U2OS) were significantly higher than that in hFOB1.19 osteoblast (P < 0.05). The vector pcDNA-MACC1 contributed to the increase of MACC1 level in MG-63 cells, whereas MACC1 siRNA evoked the decrease of MACC1 level in U2OS cells. In addition, MACC1 downregualtion caused the inhibition of cell proliferation in vitro, colony formation, invasion and tumor growth in vivo, arrested cell cycle in G0/G1 phase and induced cell apoptosis in U2OS cells, and reversed effects were observed in MG-63 cells by MACC1 upregulation. Most notably, MACC1 depletion markedly inactivated Akt signaling pathway in U2OS cells, conversely, MACC1 upregulation evidently activated Akt signaling pathway in MG-63 cells. Collectively, our data presented herein suggest that biological implications triggered by MACC1 may be tightly associated with the status of Akt signaling pathway in OS.

Functional characterization of stromal osteopontin in melanoma progression and metastasis

BACKGROUND

Recent studies demonstrated that not only tumor derived- but stroma derived factors play crucial role in cancer development. Osteopontin (OPN) is a secreted non-collagenous, sialic acid rich, chemokine-like phosphoglycoprotein that facilitates cell-matrix interactions and promotes tumor progression. Elevated level of OPN has been shown in melanoma patient and predicted as a prognostic marker. Recent reports have indicated that stroma-derived OPN are involved in regulating stem cell microenvironment and pre-neoplastic cell growth. However, the function of stroma derived OPN in regulation of side population (SP) enrichment leading to melanoma growth, angiogenesis and metastasis is not well studied and yet to be the focus of intense investigation.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, using melanoma model, in wild type and OPN knockout mice, we have demonstrated that absence of host OPN effectively curbs melanoma growth, angiogenesis and metastasis. Melanoma cells isolated from tumor of OPN wild type (OPN(+/+)) mice exhibited more tumorigenic feature as compared to the parental cell line or cells isolated from the tumors of OPN KO (OPN(-/-)) mice. Furthermore, host OPN induces VEGF, ABCG2 and ERK1/2 expression and activation in B16-WT cells. We report for the first time that stroma derived OPN regulates SP phenotype in murine melanoma cells. Moreover, loss in and gain of function studies demonstrated that stroma-derived OPN regulates SP phenotype specifically through ERK2 activation.

CONCLUSIONS

This study establish at least in part, the molecular mechanism underlying the role of host OPN in melanoma growth and angiogenesis, and better understanding of host OPN-tumor interaction may assist the advancement of novel therapeutic strategy for the management of malignant melanoma.

Anthocyanins from Vitis coignetiae Pulliat Inhibit Cancer Invasion and Epithelial-Mesenchymal Transition, but These Effects Can Be Attenuated by Tumor Necrosis Factor in Human Uterine Cervical Cancer HeLa Cells

Recently we have demonstrated that anthocyanins from fruits of Vitis coignetiae Pulliat (AIMs) have anticancer effects. Here, we investigate the effects of AIMs on cell proliferation and invasion as well as epithelial-mesenchymal transition (EMT) which have been linked to cancer metastasis in human uterine cervical cancer HeLa cells. AIMs inhibited the invasion of HeLa cells in a dose-dependent manner. AIMs inhibited MMP-9 expression in a dose-dependent manner. AIMs inhibited the motility of HeLa cells in a wound healing test. AIMs still suppressed NF- κ B activation induced by TNF. AIMs also inhibited EMT in HeLa cells. AIMs suppressed vimentin, N-cadherin, and β-catenin expression and induced E-cadherin. AIMs also suppressed expression of β-catenin and Snail, which was regulated by GSK-3. These effects of AIMs were also limited in the HeLa cells treated with TNF. In conclusion, this study indicates that AIMs have anticancer effects by suppressing NF- κ B-regulated genes and EMT, which relates to suppression of I κ B α phosphorylation and GSK-3 activity, respectively. However, the effects of AIMs were attenuated in the TNF-high condition.

Osteopontin signaling upregulates cyclooxygenase-2 expression in tumor-associated macrophages leading to enhanced angiogenesis and melanoma growth via α9β1 integrin

Tumor-associated macrophages (TAMs) have multifaceted roles in tumor development, particularly linked with tumor angiogenesis and invasion, but the molecular mechanism underlying this association remains unclear. In this study, we report that lack of osteopontin (OPN) suppresses melanoma growth in opn(-/-) mice and macrophages are the crucial component responsible for OPN-regulated melanoma growth. In tumor microenvironment, OPN activates macrophages and influences angiogenesis by enhancing cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production in an autocrine manner. Furthermore, we identify α9β1 integrin as a functional receptor for OPN that mediates its effect and activates ERK and p38 signaling, which ultimately leads to COX-2 expression in macrophages. The major role played by OPN and PGE2 in angiogenesis are further amplified by upregulation of MMP-9. OPN-activated macrophages promote the migration of endothelial and cancer cells via PGE2. These findings provide evidence that TAMs serve as source of key components such as OPN and COX-2-derived PGE2 and MMP-9 in melanoma microenvironment. Clinical specimens analyses revealed that increased infiltration of OPN-positive TAMs correlate with melanoma growth and angiogenesis. These data provide compelling evidence that OPN and COX-2 expressing macrophages are obligatory factors in melanoma growth. We conclude that OPN signaling is involved in macrophage recruitment into tumor, and our results emphasize the potential role of macrophage in modulation of tumor microenvironment via secretion of OPN, PGE2 and MMP-9, which trigger angiogenesis and melanoma growth. Thus, blockade of OPN and its regulated signaling network provides unique strategy to eradicate melanoma by manipulating TAMs.

Wasting mechanisms in muscular dystrophy

Muscular dystrophy is a group of more than 30 different clinical genetic disorders that are characterized by progressive skeletal muscle wasting and degeneration. Primary deficiency of specific extracellular matrix, sarcoplasmic, cytoskeletal, or nuclear membrane protein results in several secondary changes such as sarcolemmal instability, calcium influx, fiber necrosis, oxidative stress, inflammatory response, breakdown of extracellular matrix, and eventually fibrosis which leads to loss of ambulance and cardiac and respiratory failure. A number of molecular processes have now been identified which hasten disease progression in human patients and animal models of muscular dystrophy. Accumulating evidence further suggests that aberrant activation of several signaling pathways aggravate pathological cascades in dystrophic muscle. Although replacement of defective gene with wild-type is paramount to cure, management of secondary pathological changes has enormous potential to improving the quality of life and extending lifespan of muscular dystrophy patients. In this article, we have reviewed major cellular and molecular mechanisms leading to muscle wasting in muscular dystrophy. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

Tomatidine inhibits invasion of human lung adenocarcinoma cell A549 by reducing matrix metalloproteinases expression

Tomatidine is an aglycone of glycoalkaloid tomatine in tomato. Tomatidine is found to possess anti-inflammatory properties and may serve as a chemosensitizer in multidrug-resistant tumor cells. However, the effect of tomatidine on cancer cell metastasis remains unclear. This study examines the effect of tomatidine on the migration and invasion of human lung adenocarcinoma A549 cell in vitro. The data demonstrates that tomatidine does not effectively inhibit the viability of A549 cells. When treated with non-toxic doses of tomatidine, cell invasion is markedly suppressed by Boyden chamber invasion assay, while cell migration is not affected. Tomatidine reduces the mRNA level of matrix metalloproteinase-2 (MMP-2), MMP-9 and increases the expression of reversion-inducing cysteine-rich protein with kazal motifs (RECK), as well as tissue inhibitor of metalloproteinase-1 (TIMP-1). The immunoblotting assays indicate that tomatidine is very effective in suppressing the phosphorylation of Akt and extracellular signal regulating kinase (ERK). In addition, tomatidine significantly decreases the nuclear level of nuclear factor kappa B (NF-κB), which suggests that tomatidine inhibits NF-κB activity. Furthermore, the treatment of inhibitors specific for PI3K/Akt (LY294002), ERK (U0126), or NF-κB (pyrrolidine dithiocarbamate) to A549 cells reduced cell invasion and MMP-2/9 expression. The results suggest that tomatidine inhibits the invasion of A549 cells by reducing the expression of MMPs. It also inhibits ERK and Akt signaling pathways and NF-κB activity. These findings demonstrate a new therapeutic potential for tomatidine in anti-metastatic therapy.