Matrix metalloproteinase (MMP)-13 regulates mammary tumor-induced osteolysis by activating MMP9 and transforming growth factor-beta signaling at the tumor-bone interface

Contribution of Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 to Upper Tract Urothelial Cancer Risk in Taiwan

Matrix metalloproteinase (MMP)-2 and -9, which degrade type IV collagen, are linked to cancer invasion and metastasis. Gene polymorphisms in MMP-2 and MMP-9 can influence their function, impacting cancer development and progression. This study analyzed the association between polymorphisms MMP-2 rs243865 (C-1306T), rs2285053 (C-735T), and MMP-9 rs3918242 (C-1562T) with serum concentrations of these enzymes in upper tract urothelial cancer (UTUC) patients. We conducted a case-control study with 218 UTUC patients and 580 healthy individuals in Taiwan. Genotyping was performed using PCR/RFLP on DNA from blood samples, and MMP-2 and MMP-9 serum levels and mRNA expressions in 30 UTUC patients were measured using ELISA and real-time PCR. Statistical analysis showed that MMP-2 rs2285053 and MMP-9 rs3918242 genotypes were differently distributed between UTUC patients and controls (p = 0.0199 and 0.0020). The MMP-2 rs2285053 TT genotype was associated with higher UTUC risk compared to the CC genotype (OR = 2.20, p = 0.0190). Similarly, MMP-9 rs3918242 CT and TT genotypes were linked to increased UTUC risk (OR = 1.51 and 2.92, p = 0.0272 and 0.0054). In UTUC patients, TT carriers of MMP-2 rs2285053 and MMP-9 rs3918242 showed higher mRNA and protein levels (p < 0.01). These findings suggest that MMP-2 rs2285053 and MMP-9 rs3918242 genotypes are significant markers for UTUC risk and metastasis in Taiwan.

Protein kinase D drives the secretion of invasion mediators in triple-negative breast cancer cell lines

The protein kinase D (PKD) family members regulate the fission of cargo vesicles at the Golgi complex and play a pro-oncogenic role in triple-negative breast cancer (TNBC). Whether PKD facilitates the secretion of tumor-promoting factors in TNBC, however, is still unknown. Using the pharmacological inhibition of PKD activity and siRNA-mediated depletion of PKD2 and PKD3, we identified the PKD-dependent secretome of the TNBC cell lines MDA-MB-231 and MDA-MB-468. Mass spectrometry-based proteomics and antibody-based assays revealed a significant downregulation of extracellular matrix related proteins and pro-invasive factors such as LIF, MMP-1, MMP-13, IL-11, M-CSF and GM-CSF in PKD-perturbed cells. Notably, secretion of these proteins in MDA-MB-231 cells was predominantly controlled by PKD2 and enhanced spheroid invasion. Consistently, PKD-dependent secretion of pro-invasive factors was more pronounced in metastatic TNBC cell lines. Our study thus uncovers a novel role of PKD2 in releasing a pro-invasive secretome.

Redefining metalloproteases specificity through network proteolysis

Proteolytic processes on cell surfaces and extracellular matrix (ECM) sustain cell behavior and tissue integrity in health and disease. Matrix metalloproteases (MMPs) and a disintegrin and metalloproteases (ADAMs) remodel cell microenvironments through irreversible proteolysis of ECM proteins and cell surface bioactive molecules. Pan-MMP inhibitors in inflammation and cancer clinical trials have encountered challenges due to promiscuous activities of MMPs. Systems biology advances revealed that MMPs initiate multifactorial proteolytic cascades, creating new substrates, activating or suppressing other MMPs, and generating signaling molecules. This review highlights the intricate network that underscores the role of MMPs beyond individual substrate-enzyme activities. Gaining insight into MMP function and tissue specificity is crucial for developing effective drug discovery strategies and novel therapeutics. This requires considering the dynamic cellular processes and consequences of network proteolysis.

Tripartite motif-containing 9 promoted proliferation and migration of bladder cancer cells through CEACAM6-Smad2/3 axis

Studies have shown that tripartite motif-containing (TRIM) family proteins function as E3 ubiquitin ligases and play essential roles in cancer biology. In the present study, we validated a contribution of TRIM9 to bladder cancer progression. 296 patients derived from The Cancer Genome Atlas (TCGA) database and 22 clinical specimens were included, in which accumulated TRIM9 correlated with the poor prognosis and higher relapse in bladder patients. In vitro, TRIM9 promoted bladder cancer cells Biu-87 and T24 cell proliferation and migration. Meanwhile, overexpression of TRIM9 reduced the chemosensitivity in Biu-87 and T24 to mitomycin C (MMC) and gemcitabine (GEM). As an underlying mechanism, we found that TRIM9 stimulated carcinoembryonic antigen 6 (CEACAM6) upregulation, which further facilitated Smad2/3-matrix metalloproteinase 2 (MMP2) signaling activation both in vitro and in vivo. Those results indicated that TRIM9 facilitated bladder cancer development and chemoresistance by CEACAM6-Smad2/3 axis. TRIM9 and its associated molecules could be a potential diagnostic indicator and therapeutic target in bladder cancer.

Actin cytoskeleton depolymerization increases matrix metalloproteinase gene expression in breast cancer cells by promoting translocation of cysteine-rich protein 2 to the nucleus

The actin cytoskeleton plays a critical role in cancer cell invasion and metastasis; however, the coordination of its multiple functions remains unclear. Actin dynamics in the cytoplasm control the formation of invadopodia, which are membrane protrusions that facilitate cancer cell invasion by focusing the secretion of extracellular matrix-degrading enzymes, including matrix metalloproteinases (MMPs). In this study, we investigated the nuclear role of cysteine-rich protein 2 (CRP2), a two LIM domain-containing F-actin-binding protein that we previously identified as a cytoskeletal component of invadopodia, in breast cancer cells. We found that F-actin depolymerization stimulates the translocation of CRP2 into the nucleus, resulting in an increase in the transcript levels of pro-invasive and pro-metastatic genes, including several members of the MMP gene family. We demonstrate that in the nucleus, CRP2 interacts with the transcription factor serum response factor (SRF), which is crucial for the expression of MMP-9 and MMP-13. Our data suggest that CRP2 and SRF cooperate to modulate of MMP expression levels. Furthermore, Kaplan-Meier analysis revealed a significant association between high-level expression of SRF and shorter overall survival and distant metastasis-free survival in breast cancer patients with a high CRP2 expression profile. Our findings suggest a model in which CRP2 mediates the coordination of cytoplasmic and nuclear processes driven by actin dynamics, ultimately resulting in the induction of invasive and metastatic behavior in breast cancer cells.

Upregulated SSB Is Involved in Hepatocellular Carcinoma Progression and Metastasis through the Epithelial-Mesenchymal Transition, Antiapoptosis, and Altered ROS Level Pathway

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Therefore, finding new diagnostic and therapeutic targets is vital for HCC patients. Recent studies have shown that dysregulation of RNA-binding proteins is often associated with cancer progression. Several studies have reported that the RNA-binding protein SSB can promote cancer occurrence and progression and is linked to tumor epithelial-mesenchymal transition (EMT), which could be a new diagnostic marker and therapeutic target. However, the expression and function of SSB in HCC remain to be elucidated. Therefore, this study is aimed at clarifying the expression and biological function of SSB in HCC through bioinformatics analysis combined with in vitro experiments. We found that SSB is highly expressed in HCC and is associated with the poor prognosis of HCC patients, and it can serve as an independent unfavorable prognostic factor. Knockdown of SSB can inhibit the growth of HCC cells in vitro, increase the level of apoptosis and the expression of pro-apoptosis-related proteins, and decrease the expression of antiapoptotic proteins. Meanwhile, SSB knockdown reduced HCC cell invasiveness, and the expression of EMT-related proteins changed significantly. We also found that the gene SSB was associated with the level of oxidative stress in liver cancer cells, and the level of intracellular reactive oxygen species (ROS) increased after knockdown of SSB. The results of bioinformatics analysis also showed that high expression of SSB may affect the effect of checkpoint blockade (ICB) therapy. In conclusion, we found that SSB is highly expressed in HCC and that upregulated SSB can promote the proliferation and metastasis of HCC through antiapoptotic, altered intracellular oxidative stress level, and EMT pathways, which can serve as a new diagnostic marker and therapeutic target, and patients with high SSB expression may not have obvious ICB therapy effect.

Meso-Hannokinol inhibits breast cancer bone metastasis via the ROS/JNK/ZEB1 axis

Distal metastases from breast cancer, especially bone metastases, are extremely common in the late stages of the disease and are associated with a poor prognosis. EMT is a biomarker of the early process of bone metastasis, and MMP-9 and MMP-13 are important osteoclastic activators. Previously, we found that meso-Hannokinol (HA) could significantly inhibit EMT and MMP-9 and MMP-13 expressions in breast cancer cells. On this basis, we further explored the role of HA in breast cancer bone metastasis. In vivo, we established a breast cancer bone metastasis model by intracardially injecting breast cancer cells. Intraperitoneal injections of HA significantly reduced breast cancer cell metastasis to the leg bone in mice and osteolytic lesions caused by breast cancer. In vitro, HA inhibited the migration and invasion of breast cancer cells and suppressed the expressions of EMT, MMP-9, MMP-13, and other osteoclastic activators. HA inhibited EMT and MMP-9 by activating the ROS/JNK pathway as demonstrated by siJNK and SP600125 inhibition of JNK phosphorylation and NAC scavenging of ROS accumulation. Moreover, HA promoted bone formation and inhibited bone resorption in vitro. In conclusion, our findings suggest that HA may be an excellent candidate for treating breast cancer bone metastasis.

Matrix metalloproteinases as therapeutic targets in breast cancer

Matrix metalloproteinases (MMPs) are the most prominent proteinases involved in tumorigenesis. They were initially recognized to promote tumor progression by remodeling the extracellular matrix through their proteolytic activity. However, accumulating evidence has revealed that some MMPs have protective roles in cancer progression, and the same MMP can exert opposing roles depending on the cell type in which it is expressed or the stage of cancer. Moreover, studies have shown that MMPs are involved in cancer progression through their roles in other biological processes such as cell signaling and immune regulation, independent of their catalytic activity. Despite the prognostic significance of tumoral or stromal expression of MMPs in breast cancer, their roles and molecular mechanisms in breast cancer progression remain unclear. As the failures of early clinical trials with broad-spectrum MMP inhibitors were mainly due to a lack of drug specificity, substantial efforts have been made to develop highly selective MMP inhibitors. Some recently developed MMP inhibitory monoclonal antibodies demonstrated promising anti-tumor effects in preclinical models of breast cancer. Importantly, anti-tumor effects of these antibodies were associated with the modulation of tumor immune microenvironment, suggesting that the use of MMP inhibitors in combination with immunotherapy can improve the efficacy of immunotherapy in HER2-positive or triple-negative breast cancer. In this review, the current understanding of the roles of tumoral or stromal MMPs in breast cancer is summarized, and recent advances in the development of highly selective MMP inhibitors are discussed.

Oligonucleotide Therapeutics for Age-Related Musculoskeletal Disorders: Successes and Challenges

Age-related disorders of the musculoskeletal system including sarcopenia, osteoporosis and arthritis represent some of the most common chronic conditions worldwide, for which there remains a great clinical need to develop safer and more efficacious pharmacological treatments. Collectively, these conditions involve multiple tissues, including skeletal muscle, bone, articular cartilage and the synovium within the joint lining. In this review, we discuss the potential for oligonucleotide therapies to combat the unmet clinical need in musculoskeletal disorders by evaluating the successes of oligonucleotides to modify candidate pathological gene targets and cellular processes in relevant tissues and cells of the musculoskeletal system. Further, we discuss the challenges that remain for the clinical development of oligonucleotides therapies for musculoskeletal disorders and evaluate some of the current approaches to overcome these.

Regulation and Function of Matrix Metalloproteinase-13 in Cancer Progression and Metastasis

Matrix metalloproteinase-13 (MMP-13) is a member of the Matrix metalloproteinases (MMPs) family of endopeptidases. MMP-13 is produced in low amounts and is well-regulated during normal physiological conditions. Its expression and secretion are, however, increased in various cancers, where it plays multiple roles in tumour progression and metastasis. As an interstitial collagenase, MMP-13 can proteolytically cleave not only collagens I, II and III, but also a range of extracellular matrix proteins (ECMs). Its action causes ECM remodelling and often leads to the release of various sequestered growth and angiogenetic factors that promote tumour cell growth, invasion and angiogenesis. This review summarizes our current understanding of the regulation of MMP-13 expression and secretion and discusses the actions of MMP-13 in cancer progression and metastasis.

Caveolin-1-Derived Peptide Reduces ER Stress and Enhances Gelatinolytic Activity in IPF Fibroblasts

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by an excess deposition of extracellular matrix in the pulmonary interstitium. Caveolin-1 scaffolding domain peptide (CSP) has been found to mitigate pulmonary fibrosis in several animal models. However, its pathophysiological role in IPF is obscure, and it remains critical to understand the mechanism by which CSP protects against pulmonary fibrosis. We first studied the delivery of CSP into cells and found that it is internalized and accumulated in the Endoplasmic Reticulum (ER). Furthermore, CSP reduced ER stress via suppression of inositol requiring enzyme1α (IRE1α) in transforming growth factor β (TGFβ)-treated human IPF lung fibroblasts (hIPF-Lfs). Moreover, we found that CSP enhanced the gelatinolytic activity of TGFβ-treated hIPF-Lfs. The IRE1α inhibitor; 4µ8C also augmented the gelatinolytic activity of TGFβ-treated hIPF-Lfs, supporting the concept that CSP induced inhibition of the IRE1α pathway. Furthermore, CSP significantly elevated expression of MMPs in TGFβ-treated hIPF-Lfs, but conversely decreased the secretion of collagen 1. Similar results were observed in two preclinical murine models of PF, bleomycin (BLM)- and adenovirus expressing constitutively active TGFβ (Ad-TGFβ)-induced PF. Our findings provide new insights into the mechanism by which lung fibroblasts contribute to CSP dependent protection against lung fibrosis.

Transcriptome Profiling of Osteoblasts in a Medaka (Oryzias latipes) Osteoporosis Model Identifies Mmp13b as Crucial for Osteoclast Activation

Matrix metalloproteases (MMPs) play crucial roles in extracellular matrix (ECM) modulation during osteoclast-driven bone remodeling. In the present study, we used transcriptome profiling of bone cells in a medaka model for osteoporosis and bone regeneration to identify factors critical for bone remodeling and homeostasis. This identified mmp13b, which was strongly expressed in osteoblast progenitors and upregulated under osteoporotic conditions and during regeneration of bony fin rays. To characterize the role of mmp13b in bone remodeling, we generated medaka mmp13b mutants by CRISPR/Cas9. We found that mmp13b mutants form normal numbers of osteoblasts and osteoclasts. However, osteoclast activity was severely impaired under osteoporotic conditions. In mmp13b mutants and embryos treated with the MMP13 inhibitor CL-82198, unmineralized collagens and mineralized bone matrix failed to be degraded. In addition, the dynamic migratory behavior of activated osteoclasts was severely affected in mmp13b mutants. Expression analysis showed that maturation genes were downregulated in mmp13b deficient osteoclasts suggesting that they remain in an immature and non-activated state. We also found that fin regeneration was delayed in mmp13b mutants with a concomitant alteration of the ECM and reduced numbers of osteoblast progenitors in regenerating joint regions. Together, our findings suggest that osteoblast-derived Mmp13b alters the bone ECM to allow the maturation and activation of osteoclasts during bone remodeling in a paracrine manner. Mmp13b-induced ECM alterations are also required to facilitate osteoblast progenitor recruitment and full regeneration of bony fin rays.

GPNMB overexpression is associated with extensive bone metastasis and poor prognosis in renal cell carcinoma

Glycoprotein non-metastatic protein B (GPNMB) promotes bone metastasis (BM) in various types of cancer. However, GPNMB expression and its function in patients with renal cell carcinoma (RCC) and BM is still unknown. Therefore, the clinical significance of GPNMB and its biological function in RCC with BM was investigated in the present study. A total of 31 patients with RCC and BM were retrospectively collected. The association between GPNMB protein expression level on the primary tumor and the clinicopathological characteristics of the patients was analyzed. Kaplan-Meier analysis was used to investigate the association between GPNMB expression and the prognosis of the patients. The effects of GPNMB inhibition on cell proliferation, migration and invasion in RCC cells were investigated using short hairpin (sh)RNA. High GPNMB expression level was significantly associated with the number (P=0.001) and the extent of BM (P=0.001), Fuhrman grade (P=0.037), and ERK expression level (P=0.003) of the primary tumor. In addition, GPNMB overexpression was significantly associated with poor prognosis with respect to overall survival time (P=0.001). Furthermore, a specific shRNA sequence targeting the GPNMB gene was constructed and transduced into the ACHN cell line, using a lentivirus vector to obtain a stable cell line with low mRNA expression level of GPNMB. Low GPNMB expression level inhibited RCC cell proliferation, which was measured using a Cell Counting Kit-8 assay. Cell migration and invasion ability was significantly decreased in GPNMB knockdown RCC cells compared with that in cells transduced with the negative control shRNA. In addition, the protein expression levels of phosphorylated ERK were lower in the GPNMB shRNA-transduced ACHN cells compared with those in the control cells. Therefore, these results suggested that GPNMB plays an important role in tumor progression in RCC with BM. Furthermore, it might serve as a predictive marker for BM and as a poor prognostic factor in RCC with BM. GPNMB downregulation suppressed the proliferation, migration and invasion of the RCC cells, which may be mediated through the inhibition of the ERK signaling pathway.

Tissue plasminogen activator rescues steroid-induced outflow facility reduction via non-enzymatic action

PURPOSE

Tissue plasminogen activator (tPA) prevents steroid-induced reduction in aqueous humor outflow facility; however, its mechanism of action at the trabecular meshwork (TM) remains unclear. Enzymatic and non-enzymatic domains allow tPA to function as both an enzyme and a cytokine. This study sought to determine whether cytokine activity is sufficient to rescue steroid-induced outflow facility reduction.

METHODS

Outflow facility was measured in C57BL/6J mice following triamcinolone acetonide exposure and either transfection of the TM using adenoviral vectors, encoding for enzymatically active and inactive tPA, or administration of the respective proteins. Protein injections were also administered to tPA deficient (PlatKO) and Mmp-9 deficient (Mmp-9KO) mice to determine the potential to rescue reductions in outflow facility and determine downstream mechanisms. Gene expression of matrix metalloproteinases (Mmp-2, -9, and -13) was measured in angle ring tissues containing the TM.

RESULTS

Enzymatically active and inactive tPA (either produced after TM transfection or after direct administration) were equally effective in attenuating steroid-induced outflow facility reduction in C57BL/6J mice. They were also equally effective in rescuing outflow reduction in PlatKO mice and causing enhanced expression of matrix metalloproteinases. However, both enzymatically active and enzymatically inactive tPA did not improve outflow reduction in Mmp-9KO mice or increase the baseline outflow facility in naïve C57BL/6J mice.

CONCLUSIONS

tPA enzymatic activity is not necessary in the regulation of aqueous humor outflow. tPA can increase the expression of matrix metalloproteinases in a cytokine-mediated fashion. This cascade of events may eventually lead to extracellular matrix remodeling at the TM, which reverses outflow facility reduction caused by steroids.

Sauchinone inhibits the proliferation, migration and invasion of breast cancer cells by suppressing Akt-CREB-MMP13 signaling pathway

Sauchinone, a lignan isolated from Saururus chinenesis, is known to exhibit anti-inflammatory and anti-oxidant effects. Recently, sauchinone has been reported to inhibit the growth of various cancer cells, but its effects on breast cancer cells remain poorly understood. In the present study, we investigated the effects of sauchinone on the growth of breast cancer cells along with the underlying molecular mechanisms. Our results show that sauchinone treatment markedly inhibited the proliferation, migration, and invasion of breast cancer cells. Sauchinone reduced the phosphorylation of Akt, ERK, and CREB increased by transforming growth factor-β (TGF-β). In particular, sauchinone treatment suppressed the expression of matrix metalloproteinase (MMP)-13 (MMP13) by regulating the Akt-CREB signaling pathway. Sauchinone was less effective in inhibiting cell migration in Mmp13-knockdown cells than in control cells, suggesting that MMP13 may be a novel target for sauchinone. Our study suggests that sauchinone inhibits the growth of breast cancer cells by attenuating the Akt-CREB-MMP13 pathway. In addition, the targeted inhibition of MMP13 by sauchinone represents a promising approach for the treatment of breast cancer.

Influence of Gestational Hormones on the Bacteria-Induced Cytokine Response in Periodontitis

Periodontitis is an inflammatory disease that affects the supporting structures of teeth. The presence of a bacterial biofilm initiates a destructive inflammatory process orchestrated by various inflammatory mediators, most notably proinflammatory cytokines, which are upregulated in the gingival crevicular fluid, leading to the formation of periodontal pockets. This represents a well-characterized microbial change during the transition from periodontal health to periodontitis; interestingly, the gestational condition increases the risk and severity of periodontal disease. Although the influence of periodontitis on pregnancy has been extensively reviewed, the relationship between pregnancy and the development/evolution of periodontitis has been little studied compared to the effect of periodontitis on adverse pregnancy outcomes. This review is aimed at summarizing the findings on the pregnancy-proinflammatory cytokine relationship and discussing its possible involvement in the development of periodontitis. We address (1) an overview of periodontal disease, (2) the immune response and possible involvement of proinflammatory cytokines in the development of periodontitis, (3) how bone tissue remodelling takes place with an emphasis on the involvement of the inflammatory response and metalloproteinases during periodontitis, and (4) the influence of hormonal profile during pregnancy on the development of periodontitis. Finally, we believe this review may be helpful for designing immunotherapies based on the stage of pregnancy to control the severity and pathology of periodontal disease.

Targeting integrin αvβ3 with indomethacin inhibits patient-derived xenograft tumour growth and recurrence in oesophageal squamous cell carcinoma

RATIONALE

A high risk of post-operative recurrence contributes to the poor prognosis and low survival rate of oesophageal squamous cell carcinoma (ESCC) patients. Increasing experimental evidence suggests that integrin adhesion receptors, in particular integrin αv (ITGAV), are important for cancer cell survival, proliferation and migration. Therefore, targeting ITGAV may be a rational approach for preventing ESCC recurrence.

MATERIALS AND METHODS

Protein levels of ITGAV were determined in human ESCC tumour tissues using immunohistochemistry. MTT, propidium iodide staining, and annexin V staining were utilized to investigate cell viability, cell cycle progression, and induction of apoptosis, respectively. Computational docking was performed with the Schrödinger Suite software to visualize the interaction between indomethacin and ITGAV. Cell-derived xenograft mouse models, patient-derived xenograft (PDX) mouse models, and a humanized mouse model were employed for in vivo studies.

RESULTS

ITGAV was upregulated in human ESCC tumour tissues and increased ITGAV protein levels were associated with poor prognosis. ITGAV silencing or knockout suppressed ESCC cell growth and metastatic potential. Interestingly, we identified that indomethacin can bind to ITGAV and enhance synovial apoptosis inhibitor 1 (SYVN1)-mediated degradation of ITGAV. Integrin β3, one of the β subunits of ITGAV, was also decreased at the protein level in the indomethacin treatment group. Importantly, indomethacin treatment suppressed ESCC tumour growth and prevented recurrence in a PDX mouse model. Moreover, indomethacin inhibited the activation of cytokine TGFβ, reduced SMAD2/3 phosphorylation, and increased anti-tumour immune responses in a humanized mouse model.

CONCLUSION

ITGAV is a promising therapeutic target for ESCC. Indomethacin can attenuate ESCC growth through binding to ITGAV, promoting SYVN1-mediated ubiquitination of ITGAV, and potentiating cytotoxic CD8+ T cell responses.

A new MMP-mediated prodomain cleavage mechanism to activate bone morphogenetic proteins from the extracellular matrix

Since their discovery as pluripotent cytokines extractable from bone matrix, it has been speculated how bone morphogenetic proteins (BMPs) become released and activated from the extracellular matrix (ECM). In contrast to TGF-βs, most investigated BMPs are secreted as bioactive prodomain (PD)-growth factor (GF) complexes (CPLXs). Recently, we demonstrated that PD-dependent targeting of BMP-7 CPLXs to the extracellular fibrillin microfibril (FMF) components fibrillin-1 and -2 represents a BMP sequestration mechanism by rendering the GF latent. Understanding how BMPs become activated from ECM scaffolds such as FMF is crucial to elucidate pathomechanisms characterized by aberrant BMP activation and ECM destruction. Here, we describe a new MMP-dependent BMP-7 activation mechanism from ECM-targeted pools via specific PD degradation. Using Edman sequencing and mutagenesis, we identified a new and conserved MMP-13 cleavage site within the BMP-7 PD. A degradation screen with different BMP family PDs and representative MMP family members suggested utilization of the identified site in a general MMP-driven BMP activation mechanism. Furthermore, sandwich ELISA and solid phase cleavage studies in combination with bioactivity assays, single particle TEM, and in silico molecular docking experiments provided evidence that PD cleavage by MMP-13 leads to BMP-7 CPLX disintegration and bioactive GF release.

Controlling BMP growth factor bioavailability: The extracellular matrix as multi skilled platform

Bone morphogenetic proteins (BMPs) belong to the TGF-β superfamily of signaling ligands which comprise a family of pluripotent cytokines regulating a multitude of cellular events. Although BMPs were originally discovered as potent factors extractable from bone matrix that are capable to induce ectopic bone formation in soft tissues, their mode of action has been mostly studied as soluble ligands in absence of the physiologically relevant cellular microenvironment. This micro milieu is defined by supramolecular networks of extracellular matrix (ECM) proteins that specifically target BMP ligands, present them to their cellular receptors, and allow their controlled release. Here we focus on functional interactions and mechanisms that were described to control BMP bioavailability in a spatio-temporal manner within the respective tissue context. Structural disturbance of the ECM architecture due to mutations in ECM proteins leads to dysregulated BMP signaling as underlying cause for connective tissue disease pathways. We will provide an overview about current mechanistic concepts of how aberrant BMP signaling drives connective tissue destruction in inherited and chronic diseases.

Matrix Metalloproteinase 13 Inhibitors for Modulation of Osteoclastogenesis: Enhancement of Solubility and Stability

Matrix metalloproteinase 13 (MMP-13) activity has been correlated to breast cancer bone metastasis. It has been proposed that MMP-13 contributes to bone metastasis through the promotion of osteoclastogenesis. To explore the mechanisms of MMP-13 action, we previously described a highly efficacious and selective MMP-13 inhibitor, RF036. Unfortunately, further pursuit of RF036 as a probe of MMP-13 in vitro and in vivo activities was not practical due to the limited solubility and stability of the inhibitor. Our new study has explored replacing the RF036 backbone sulfur atom and terminal methyl group to create inhibitors with more favorable pharmacokinetic properties. One compound, designated inhibitor 3, in which the backbone sulfur and terminal methyl group of RF036 were replaced by nitrogen and oxetane, respectively, had comparable activity, selectivity, and membrane permeability to RF036, while exhibiting greatly enhanced solubility and stability. Inhibitor 3 effectively inhibited MMP-13-mediated osteoclastogenesis but spared collagenolysis, and thus represents a next-generation MMP-13 probe applicable for in vivo studies of breast cancer metastasis.

(2-Aminobenzothiazole)-Methyl-1,1-Bisphosphonic Acids: Targeting Matrix Metalloproteinase 13 Inhibition to the Bone

Matrix Metalloproteinases (MMPs) are a family of secreted and membrane-bound enzymes, of which 24 isoforms are known in humans. These enzymes degrade the proteins of the extracellular matrix and play a role of utmost importance in the physiological remodeling of all tissues. However, certain MMPs, such as MMP-2, -9, and -13, can be overexpressed in pathological states, including cancer and metastasis. Consequently, the development of MMP inhibitors (MMPIs) has been explored for a long time as a strategy to prevent and hinder metastatic growth, but the important side effects linked to promiscuous inhibition of MMPs prevented the clinical use of MMPIs. Therefore, several strategies were proposed to improve the therapeutic profile of this pharmaceutical class, including improved selectivity toward specific MMP isoforms and targeting of specific organs and tissues. Combining both approaches, we conducted the synthesis and preliminary biological evaluation of a series of (2-aminobenzothiazole)-methyl-1,1-bisphosphonic acids active as selective inhibitors of MMP-13 via in vitro and in silico studies, which could prove useful for the treatment of bone metastases thanks to the bone-targeting capabilities granted by the bisphosphonic acid group.

MicroRNA‑34a‑5p serves as a tumor suppressor by regulating the cell motility of bladder cancer cells through matrix metalloproteinase‑2 silencing

Bladder cancer (BC), a common urologic cancer, is the fifth most frequently diagnosed tumor worldwide. hsa-miR-34a displays antitumor activity in several types of cancer. However, the functional mechanisms underlying hsa-miR-34a in BC remains largely unknown. We observed that hsa-mir-34a levels were significantly and negatively associated with clinical disease stage as well as regional lymph node metastasis in human BC. In a series of in vitro investigations, overexpression of hsa-miR-34a inhibited cell migration and invasion in BC cell lines 5637 and UMUC3 as detected by Transwell assays. We further found that hsa-miR-34a inhibited cell migration and invasion by silencing matrix metalloproteinase-2 (MMP-2) expression and thus interrupting MMP-2-mediated cell motility. Our analysis of BC datasets from The Cancer Genome Atlas database revealed a negative correlation between hsa-miR-34a and MMP-2. Moreover, higher MMP-2 protein expression was observed in the BC tissues when compared with that noted in the normal tissue. MMP-2 levels were also significantly associated with clinical disease stage and poor survival rate in human BC. These findings indicate that MMP-2 plays a critical role in regulating BC progression. Therefore, hsa-miR-34a is a promising treatment to target MMP-2 for the prevention and inhibition of cell migration and invasion in BC.

Activating transcription factor-2 (ATF2) is a key determinant of resistance to endocrine treatment in an in vitro model of breast cancer

BACKGROUND

Activating transcription factor-2 (ATF2), a member of the leucine zipper family of DNA binding proteins, has been implicated as a tumour suppressor in breast cancer. However, its exact role in breast cancer endocrine resistance is still unclear. We have previously shown that silencing of ATF2 leads to a loss in the growth-inhibitory effects of tamoxifen in the oestrogen receptor (ER)-positive, tamoxifen-sensitive MCF7 cell line and highlighted that this multi-faceted transcription factor is key to the effects of tamoxifen in an endocrine sensitive model. In this work, we explored further the in vitro role of ATF2 in defining the resistance to endocrine treatment.

MATERIALS AND METHODS

We knocked down ATF2 in TAMR, LCC2 and LCC9 tamoxifen-resistant breast cancer cell lines as well as the parental tamoxifen sensitive MCF7 cell line and investigated the effects on growth, colony formation and cell migration. We also performed a microarray gene expression profiling (Illumina Human HT12_v4) to explore alterations in gene expression between MCF7 and TAMRs after ATF2 silencing and confirmed gene expression changes by quantitative RT-PCR.

RESULTS

By silencing ATF2, we observed a significant growth reduction of TAMR, LCC2 and LCC9 with no such effect observed with the parental MCF7 cells. ATF2 silencing was also associated with a significant inhibition of TAMR, LCC2 and LCC9 cell migration and colony formation. Interestingly, knockdown of ATF2 enhanced the levels of ER and ER-regulated genes, TFF1, GREB1, NCOA3 and PGR, in TAMR cells both at RNA and protein levels. Microarray gene expression identified a number of genes known to mediate tamoxifen resistance, to be differentially regulated by ATF2 in TAMR in relation to the parental MCF7 cells. Moreover, differential pathway analysis confirmed enhanced ER activity after ATF2 knockdown in TAMR cells.

CONCLUSION

These data demonstrate that ATF2 silencing may overcome endocrine resistance and highlights further the dual role of this transcription factor that can mediate endocrine sensitivity and resistance by modulating ER expression and activity.

Destroy to Rebuild: The Connection Between Bone Tissue Remodeling and Matrix Metalloproteinases

Bone is a dynamic organ that undergoes constant remodeling, an energetically costly process by which old bone is replaced and localized bone defects are repaired to renew the skeleton over time, thereby maintaining skeletal health. This review provides a general overview of bone’s main players (bone lining cells, osteocytes, osteoclasts, reversal cells, and osteoblasts) that participate in bone remodeling. Placing emphasis on the family of extracellular matrix metalloproteinases (MMPs), we describe how: (i) Convergence of multiple protease families (including MMPs and cysteine proteinases) ensures complexity and robustness of the bone remodeling process, (ii) Enzymatic activity of MMPs affects bone physiology at the molecular and cellular levels and (iii) Either overexpression or deficiency/insufficiency of individual MMPs impairs healthy bone remodeling and systemic metabolism. Today, it is generally accepted that proteolytic activity is required for the degradation of bone tissue in osteoarthritis and osteoporosis. However, it is increasingly evident that inactivating mutations in MMP genes can also lead to bone pathology including osteolysis and metabolic abnormalities such as delayed growth. We argue that there remains a need to rethink the role played by proteases in bone physiology and pathology.

The role of MMP-2 and MMP-9 in the metastasis and development of hypopharyngeal carcinoma

Introduction

The role of matrix metalloproteinase-2 and 9 in the metastasis and development of hypopharyngeal carcinoma has not been clarified.

Objectives

To observe the relationship between matrix metalloproteinase-2, matrix metalloproteinase-9 and the metastasis, development of hypopharyngeal carcinoma.

Methods

This study included 42 hypopharyngeal cancer patients. The mRNA and protein expression levels of matrix metalloproteinase-2 and 9 in hypopharyngeal carcinoma and paracancerous tissues were detected by reverse transcription-polymerase chain reaction and Western blot.

Results

Reverse transcription-polymerase chain reaction detection showed that the mRNA of matrix metalloproteinase-2 and 9 was expressed in both cancer and pericarcinoma tissues, but was almost not expressed in polypoid control tissues. The expression intensity in the cancer tissue was significantly higher than that in the pericarcinoma tissue (matrix metalloproteinase-2: t ＝ 2.529, p = 0.015; matrix metalloproteinase-9: t ＝ 4.781, p ＜ 0.001). The mRNA expression in the cancer tissue was enhanced with the increase of the tumor clinical stage (matrix metalloproteinase-2: F = 4.003, p = 0.026; matrix metalloproteinase-9: F = 5.501, p = 0.008). Its expression intensity was associated with the metastasis of lymph nodes (N staging) and increased with the degree of lymphatic metastasis (matrix metalloproteinases-2: F = 8.965, p = 0.005; matrix metalloproteinase-9: F = 5.420, p = 0.025). There was no significant change in T staging of tumor. With the increase of tumor pathological stage, the mRNA expression of matrix metalloproteinase-2 and 9 was strengthened (matrix metalloproteinase-2: F = 3.884, p = 0.029; matrix metalloproteinase-9: F = 3.783, p = 0.032). The protein expression level of matrix metalloproteinase-2 and 9 was the same as that of mRNA.

Conclusion

The expression of matrix metalloproteinase-2 and 9 in hypopharyngeal carcinoma was significantly higher than that in pericarcinoma tissue, and it was enhanced with the increase of clinical stage. The expression level was related to lymph node metastasis and tumor pathological stage. Thus, matrix metalloproteinase-2 and 9 may be involved in the occurrence, development, invasion and metastasis of hypopharyngeal carcinoma through a variety of mechanisms.

Ability of S100 proteins and matrix metalloproteinase-9 to identify periodontitis in a ligature-induced periodontitis dog model

AIMS

The present study aimed to monitor the levels of selected salivary biomarkers during the development and treatment of periodontitis and to evaluate their ability to identify periodontitis in dogs.

MATERIALS AND METHODS

A total of 15 beagle dogs were divided into a control group (no ligature), group 1 (ligature on six teeth), and group 2 (ligature on 12 teeth). The experimental periods consisted of 8 weeks of periodontitis induction and 4 weeks of treatment. Clinical measurements and the sampling of saliva were performed every 4 weeks. The levels of S100A8, S100A9, S100A8/A9, and matrix metalloproteinase (MMP)-9 were measured by enzyme-linked immunosorbent assay.

RESULTS

All experimental animals and two control animals developed periodontitis, which was successfully treated. All salivary biomarkers were significantly increased in periodontitis with high diagnostic power (c-index ≥ 0.944) and were able to identify animals with periodontitis on a single tooth. Whereas the levels of salivary S100A8/A9 recovered to levels in health, those of S100A8, S100A9, and MMP-9 in periodontitis stability remained significantly higher than in health.

CONCLUSION

Salivary S100A8, S100A9, S100A8/A9, and MMP-9 may be used for the screening of periodontitis in dogs, but with caution of other conditions that can affect their levels in saliva.

Myeloid Krüppel-Like Factor 2 Critically Regulates K/BxN Serum-Induced Arthritis

Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease, and Krüppel-like factor 2 (KLF2) regulates immune cell activation and function. Herein, we show that in our experiments 50% global deficiency of KLF2 significantly elevated arthritic inflammation and pathogenesis, osteoclastic differentiation, matrix metalloproteinases (MMPs), and inflammatory cytokines in K/BxN serum-induced mice. The severities of RA pathogenesis, as well as the causative and resultant cellular and molecular factors, were further confirmed in monocyte-specific KLF2 deficient mice. In addition, induction of RA resulted in a decreased level of KLF2 in monocytes isolated from both mice and humans along with higher migration of activated monocytes to the RA sites in humans. Mechanistically, overexpression of KLF2 decreased the level of MMP9; conversely, knockdown of KLF2 increased MMP9 in monocytes along with enrichment of active histone marks and histone acetyltransferases on the MMP9 promoter region. These findings define the critical regulatory role of myeloid KLF2 in RA pathogenesis.

An integrated bioinformatics analysis of potential therapeutic targets among matrix metalloproteinases in breast cancer

Breast cancer (BC) is one of the most aggressive malignancies worldwide among females. Matrix metalloproteinases (MMPs), as the most abundant class of non-serine proteases present in invasive and metastatic tumors, can regulate a variety of alterations in the microenvironment during tumor progression. However, the differential expression of MMPs and its prognostic values in BC is yet to be elucidated. In this research, using the ONCOMINE dataset, The Cancer Genome Atlas, Breast Cancer Gene-Expression Miner v4.1 (Bc-GenExMiner), Kaplan-Meier Plotter and cBioPortal, the transcriptional MMPs and survival outcome data of patients with BC was compared. It was indicated that mRNA levels of MMP1/3/9/10/11/12/13 were increased compared with non-tumor tissues, whereas mRNA expression of MMP2/16/19/23B/28 was lower in BC tissues. Kaplan-Meier plots showed that high mRNA levels of MMP2/10/16/19/20/23B/27 in patients with BC were associated with better recurrence-free survival. In contrast, high MMP1/8/9/11/12 conferred worse RFS rate. Meanwhile, high transcription levels of MMP1/3/11/12/13 predicted shorter distant metastasis-free survival, while high levels of MMP1/12 demonstrated worse overall survival in patients with BC. From Bc-GenExMiner, it was indicated that high expression of MMP16/20 was correlated with better prognosis, while MMP1/9/11/12/13/14/15 exerted a negative effect on patient prognosis. The integrative bioinformatics analysis performed in the present study suggests that MMP1/9/12/16, compared with other MMPs, are potentially appropriate targets for targeted therapy in patients with BC.

Deciphering novel biomarkers of lymph node metastasis of thyroid papillary microcarcinoma using proteomic analysis of ultrasound-guided fine-needle aspiration biopsy samples

Thyroid papillary microcarcinoma is now a common clinical problem. Cervical lymph node metastasis is the main metastasis mode of PTMC. However, before operation, it is still difficult to determine exactly whether PTMC patient is suffering with cervical lymph node metastasis. To resolve this dilemma, for better selection of optimum treatment plans, it is necessary to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. In total, 3391 proteins of the 3793 protein groups identified were quantified. Bioinformatics analysis indicated that differentially expressed proteins were involved in multiple biological functions, metastasis-related pathways. Moreover, IFN-stimulated gene 15 proteins were found to be well distinguished between patients with lymph node metastatic and patients with nonmetastatic PTMC. Knocking down ISG15 with shRNA inhibited the xenografted tumor growth. This study provided a reference proteome map for lymph node metastatic PTMC. ISG15 probably is a prognosis marker of thyroid papillary microcarcinoma patients with lymph node metastasis. SIGNIFICANCE: Nowadays, thyroid cancer has become a widespread epidemic. The rate of thyroid cancer incidence has been faster than any other cancers, reported by the American Cancer Society. Papillary thyroid microcarcinoma (PTMC) is a subset of PTC defined as PTC measuring≤1 cm in size, which comprises nearly one-half of all the cases of PTCs. Actually, the rapidly increasing global incidence of PTC is mainly attributed to the corresponding increase in the diagnosis of PTMC. Scholars have figuratively compared the increase of PTMC to the "tsunami". The treatment scheme for PTMC is still not uniform, and the controversy is mainly focused on the necessity of surgery treatment. PTMCs often have an indolent course in the absence of evidence of metastatic cervical lymph nodes, distant metastases and extrathyroidal extension. Therefore, it is important for us to reliably differentiate the small number of PTMC patients developing significant metastases progression from the larger population of patients that harbor indolent PTMCs. The present study aimed to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags (TMT) combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy (FNAB) samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. Our results showed that some differential expression proteins were likely to be important resources for finding new diagnostic biomarkers.

Seeking for Correlative Genes and Signaling Pathways With Bone Metastasis From Breast Cancer by Integrated Analysis

Background: Bone metastasis frequently occurs in advanced breast cancer patients, and it is one of major causes of breast cancer associated mortality. The aim of the current study is to identify potential genes and related signaling pathways in the pathophysiology of breast cancer bone metastasis.

Methods: Three mRNA expression datasets for breast cancer bone metastasis were obtained from Gene Expression Omnibus (GEO) dataset. The differentially expressed genes (DEGs) were obtained. Functional analyses, protein-protein interaction (PPI) network, and transcription factors (TFs)-target genes network was constructed. Real-time PCR using clinical specimens was conducted to justify the results from integrated analysis.

Results: A 749 DEGs were obtained. Osteoclast differentiation and rheumatoid arthritis were two significantly enriched signaling pathways for DEGs in the bone metastasis of breast cancer. SMAD7 (degree = 10), TGFBR2 (degree = 9), VIM (degree = 8), FOS (degree = 8), PDGFRB (degree = 7), COL5A1 (degree = 6), ARRB2 (degree = 6), and ITGAV (degree = 6) were high degree genes in the PPI network. ETS1 (degree = 12), SPI1 (degree = 12), FOS (degree = 10), FLI1 (degree = 5), KLF4 (degree = 4), JUNB (degree = 4), NR3C1 (degree = 4) were high degree genes in the TFs-target genes network. Validated by QRT-PCR, the expression levels of IBSP, MMP9, MMP13, TNFAIP6, CD200, DHRS3, ASS1, RIPK4, VIM, and PROM1 were roughly consistent with our integrated analysis. Except PROM1, the other genes had a diagnose value for breast cancer bone metastasis.

Conclusions: The identified DEGs and signaling pathways may make contribution for understanding the pathological mechanism of bone metastasis from breast cancer.

Upregulated osterix promotes invasion and bone metastasis and predicts for a poor prognosis in breast cancer

Approximately 70% of patients with advanced breast cancer develop bone metastases, accompanied by complications, such as bone pain, fracture, and hypercalcemia. However, our understanding of the molecular mechanisms that govern this process remains fragmentary. Osterix (Osx) is a zinc finger-containing transcription factor essential for osteoblast differentiation and bone formation. Here, we identified the functional roles of Osx in facilitating breast cancer invasion and bone metastasis. Osx upregulation was associated with lymph node metastasis and was negatively prognostic for overall survival. Knockdown of Osx inhibited invasion of breast cancer and osteolytic metastasis by downregulating MMP9, MMP13, VEGF, IL-8, and PTHrP, which are involved in invasion, angiogenesis, and osteolysis; overexpression of Osx had the opposite effect. Moreover, MMP9 was a direct target of Osx and mediated the Osx-driven invasion of breast cancer cells. Together, our data showed that Osx facilitates bone metastasis of breast cancer by upregulating the expression of a cohort of genes that contribute to steps in the metastatic cascade. These findings suggest that Osx is an attractive target for the control of bone metastasis of breast cancers.

Hypoxia and the Metastatic Niche

Metastasis is considered the latest stage of cancer development; however, metastasis occurs earlier than it can be detected. Metastatic sites are actively remodeled by secretory factors including growth factors, chemokines and cytokines, extracellular matrix (ECM) enzymes, and exosomes produced by the primary cancer tissues. Many of the associated-secretory factors are abundantly induced by inflammation and hypoxia. These secretory factors modify the ECM, immune composition, and blood vessel permeability of the future metastatic sites, a process termed 'metastatic niche formation.' In general, ECM is modified to enhance the attachment of other cell types or cancer cells to establish a growth-factor rich metastatic niche. Immune-suppressive cells such as tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) dominate the metastatic niche to allow metastatic cancer cells to bypass immune surveillance and propagate. Endothelial cell-to-cell junctions of blood vessels are loosened to enhance the penetrance of metastatic cancer cells to the metastatic sites. Different metastatic tissues have unique ECM constituents, resident immune cells, and anatomical positions linked with the circulatory system; therefore, many cancer types have their own metastatic pattern, and they favor metastasis to specific organs. Some of the remodeling events represent the earliest step of metastasis, even preceding the detachment of cancer cells from the primary tumor site. Understanding how the metastatic niche is formed is important for the development of drugs to prevent the earliest step of metastasis and advance our understanding of organotrophic metastasis. This review summarizes the major findings in the field of metastatic niche highlighting the role of hypoxia.

ETV4 transcription factor and MMP13 metalloprotease are interplaying actors of breast tumorigenesis

BACKGROUND

The ETS transcription factor ETV4 is involved in the main steps of organogenesis and is also a significant mediator of tumorigenesis and metastasis, such as in breast cancer. Indeed, ETV4 is overexpressed in breast tumors and is associated with distant metastasis and poor prognosis. However, the cellular and molecular events regulated by this factor are still misunderstood. In mammary epithelial cells, ETV4 controls the expression of many genes, MMP13 among them. The aim of this study was to understand the function of MMP13 during ETV4-driven tumorigenesis.

METHODS

Different constructs of the MMP13 gene promoter were used to study the direct regulation of MMP13 by ETV4. Moreover, cell proliferation, migration, invasion, anchorage-independent growth, and in vivo tumorigenicity were assayed using models of mammary epithelial and cancer cells in which the expression of MMP13 and/or ETV4 is modulated. Importantly, the expression of MMP13 and ETV4 messenger RNA was characterized in 456 breast cancer samples.

RESULTS

Our results revealed that ETV4 promotes proliferation, migration, invasion, and anchorage-independent growth of the MMT mouse mammary tumorigenic cell line. By investigating molecular events downstream of ETV4, we found that MMP13, an extracellular metalloprotease, was an ETV4 target gene. By overexpressing or repressing MMP13, we showed that this metalloprotease contributes to proliferation, migration, and anchorage-independent clonogenicity. Furthermore, we demonstrated that MMP13 inhibition disturbs proliferation, migration, and invasion induced by ETV4 and participates to ETV4-induced tumor formation in immunodeficient mice. Finally, ETV4 and MMP13 co-overexpression is associated with poor prognosis in breast cancer.

CONCLUSION

MMP13 potentiates the effects of the ETV4 oncogene during breast cancer genesis and progression.

Osteolytic cancer cells induce vascular/axon guidance processes in the bone/bone marrow stroma

Prostate and breast cancers frequently metastasize to bone. The physiological bone homeostasis is perturbed once cancer cells proliferate at the bone metastatic site. Tumors are complex structures consisting of cancer cells and numerous stroma cells.

In this study, we show that osteolytic cancer cells (PC-3 and MDA-MB231) induce transcriptome changes in the bone/bone marrow microenvironment (stroma). This stroma transcriptome differs from the previously reported stroma transcriptome of osteoinductive cancer cells (VCaP). While the biological process “angiogenesis/vasculogenesis” is enriched in both transcriptomes, the “vascular/axon guidance” process is a unique process that characterizes the osteolytic stroma. In osteolytic bone metastasis, angiogenesis is denoted by vessel morphology and marker expression specific for arteries/arterioles. Interestingly, intra-tumoral neurite-like structures were in proximity to arteries. Additionally, we found that increased numbers of mesenchymal stem cells and vascular smooth muscle cells, expressing osteolytic cytokines and inhibitors of bone formation, contribute to the osteolytic bone phenotype.

Osteoinductive and osteolytic cancer cells induce different types of vessels, representing functionally different hematopoietic stem cell niches. This finding suggests different growth requirements of osteolytic and osteoinductive cancer cells and the need for a differential anti-angiogenic strategy to inhibit tumor growth in osteolytic and osteoblastic bone metastasis.

INAVA promotes aggressiveness of papillary thyroid cancer by upregulating MMP9 expression

Background

Innate immunity activator (INAVA) has been shown to be elevated in lung adenocarcinoma. However, its expression pattern and function in papillary thyroid cancer (PTC) are unknown. This study aimed to identify the clinical, biological, and mechanistic impacts of INAVA on PTC.

Methods

Using The Cancer Genome Atlas dataset, real time PCR, and immunohistochemistry, the expression of INAVA in PTC was analyzed. Gain- and loss-of-function assays were performed to investigate the role of INAVA in PTC cell invasion, migration, and metastasis. We explored the molecular mechanisms underlying the roles of INAVA in PTC cells using transcriptome resequencing, real time PCR, western blotting and immunohistochemistry.

Results

We found that INAVA expression was significantly upregulated in PTC and was significantly associated with lymph node metastasis. Loss- and gain-of-function experiments demonstrated that INAVA promoted the aggressive phenotype of PTC cells in vitro and in vivo. Mechanistic study suggested that upregulation of INAVA resulted in elevated fibroblast growth factor 1 (FGF1), which in turn increased the expression level of matrix metalloproteinases 9 (MMP9). We further identified that the level of INAVA was positively correlated with the levels of FGF1 and MMP9 in clinical PTC specimens.

Conclusion

These data establish a novel role for INAVA in promoting PTC progression and suggest that INAVA may represent a therapeutic target for the disease.

Electronic supplementary material

The online version of this article (10.1186/s13578-018-0224-4) contains supplementary material, which is available to authorized users.

SK-216, a Novel Inhibitor of Plasminogen Activator Inhibitor-1, Suppresses Lung Metastasis of Human Osteosarcoma

Lung metastasis constitutes the leading cause of the death in patients with osteosarcoma. We have previously reported that plasminogen activator inhibitor-1 (PAI-1) regulates the invasion and lung metastasis of osteosarcoma cells in a mouse model and as well as in clinical samples. In the present study, we examined the anti-metastatic effect of SK-216, a small compound PAI-1 inhibitor, in human 143B osteosarcoma cells. An in vitro study showed that SK-216 treatment suppressed invasion activity by inhibiting PAI-1 expression in 143B cells, but had no influence on their proliferation or migration. 143B cells treated with SK-216 exhibited reduced matrix metalloproteinase-13 (MMP-13) secretion in a dose-dependent manner. Moreover, intraperitoneal injection of SK-216 into mouse models resulted in downregulation of PAI-1 expression levels in the primary tumors and showed suppression of lung metastases without influencing the proliferative activity of the tumor cells in the primary lesions. These results indicate that SK-216, a PAI-1 inhibitor, may serve as a novel drug to prevent lung metastasis in human osteosarcoma.

CD73 Promotes Resistance to HER2/ErbB2 Antibody Therapy

Expression of the ectonucleotidase CD73 by tumor cells, stromal cells, and immune cells is associated in cancer with immune suppression. In this study, we investigated the role of CD73 on the activity of the anti-HER2/ErbB2 monoclonal antibody (mAb) trastuzumab. In a prospective, randomized phase III clinical trial evaluating the activity of trastuzumab, high levels of CD73 gene expression were associated significantly with poor clinical outcome. In contrast, high levels of PD-1 and PD-L1 were associated with improved clinical outcome. In immunocompetent mouse models of HER2/ErbB2-driven breast cancer, CD73 expression by tumor cells and host cells significantly suppressed immune-mediated responses mediated by anti-ErbB2 mAb. Furthermore, anti-CD73 mAb therapy enhanced the activity of anti-ErbB2 mAb to treat engrafted or spontaneous tumors as well as lung metastases. Gene ontology enrichment analysis from gene-expression data revealed a positive association of CD73 expression with extracellular matrix organization, TGFβ genes, epithelial-to-mesenchymal transition (EMT) transcription factors and hypoxia-inducible-factor (HIF)-1 gene signature. Human mammary cells treated with TGFβ or undergoing EMT upregulated CD73 cell-surface expression, confirming roles for these pathways. In conclusion, our findings establish CD73 in mediating resistance to trastuzumab and provide new insights into how CD73 is regulated in breast cancer. Cancer Res; 77(20); 5652-63. ©2017 AACR.

Beclin 1 overexpression inhibits chondrocyte apoptosis and downregulates extracellular matrix metabolism in osteoarthritis

In the present study, the expression of Beclin 1 in osteoarthritis (OA) cartilage tissue was investigated, and also its role in proliferation, apoptosis and expression of matrix metalloproteinases (MMPs) in chondrocytes obtained from patients with OA. Beclin 1 expression in cartilage tissue from OA patients, and in the age- and sex-matched controls, was detected by immunohistochemistry, semi-quantitative polymerase chain reaction and western blotting. Chondrocytes were divided into control and Beclin 1-overexpressed groups. After transfection for 48, 72 and 96 h, cell viability, apoptosis, the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway and MMPs were examined. The mRNA and protein expression levels of Beclin 1 were significantly decreased in cartilage tissue from OA patients compared with the sex- and age-matched controls (P<0.05). In chondrocytes from OA patients, Beclin 1 overexpression significantly increased cell viability (P<0.05). Beclin 1 overexpression additionally decreased the degree of apoptosis, as demonstrated by Hoechst staining and flow cytometric analysis. B-cell lymphoma-2 (Bcl-2) was upregulated, and Bcl-2 associated X was downregulated, following Beclin 1 overexpression (P<0.05). The PI3K/Akt/mTOR signaling pathway was mitigated following Beclin 1 overexpression (P<0.05). In addition, MMP1, MMP3 and MMP13 were downregulated after Beclin 1 overexpression (P<0.05). Taken together, low expression levels of Beclin 1 may contribute towards the degeneration of chondrocytes. Beclin 1 overexpression increased cell viability, inhibited apoptosis and MMPs, likely via the PI3K/Akt/mTOR signaling pathway.

Bone metastasis-related signaling pathways in breast cancers stratified by estrogen receptor status

Background: Breast cancer bone metastasis (BCBM)-specific genes have been reported without considering biological differences based on estrogen receptor (ER) status. The aims of this study were to identify BCBM-specific genes using our patient dataset and validate previously reported BCBM-specific genes, and to determine whether ER-status-related biological differences matter in identification of BCBM-specific genes.

Methods: We used Affymetrix GeneChips to analyze 365 primary human epidermal growth factor receptor 2 (HER2)-negative invasive breast cancer specimens. Genes that were differentially expressed between patients who developed bone metastasis and those who developed non-bone metastasis were identified using Cox proportional hazards model, and differential expression of gene sets was assessed using gene set analysis. We performed gene set analysis to determine whether biological function associated with bone metastasis were different by ER status using 2,246 functionally annotated gene sets assembled from Gene Ontology data base.

Results: Among 16,712 probe sets, 592 were overexpressed in the bone metastasis cohort compared to the non-bone-metastasis cohort (false discovery rate ≤ 0.05). However, no BCBM-specific genes met our significance tests when the cancers were stratified by ER status. In ER-positive and ER-negative breast cancers, 151 and 125 gene sets, respectively, were overexpressed for BCBM and the majority of BCBM-related pathways were different. Of significant gene sets, only 13 gene sets were overlapped between ER-positive and -negative cohorts.

Conclusion: ER-positive and ER-negative breast cancers have different biological pathways in BCBM development. We have yet to explore BCBM-related biomarkers and targets considering the biological features associated with BCBM depending on the ER status.

Matrix Metalloproteinases as Regulators of Periodontal Inflammation

Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss. Matrix metalloproteinases (MMPs) are key proteases involved in destructive periodontal diseases. The study and interest in MMP has been fuelled by emerging evidence demonstrating the broad spectrum of molecules that can be cleaved by them and the myriad of biological processes that they can potentially regulate. The huge complexity of MMP functions within the 'protease web' is crucial for many physiologic and pathologic processes, including immunity, inflammation, bone resorption, and wound healing. Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates, they cleave several signalling molecules-such as cytokines, chemokines, and growth factors, among others-regulating their biological functions and/or bioavailability during periodontal diseases. In this review, we provide an overview of emerging evidence of MMPs as regulators of periodontal inflammation.

ATP6V1H Deficiency Impairs Bone Development through Activation of MMP9 and MMP13

ATP6V1H is a component of a large protein complex with vacuolar ATPase (V-ATPase) activity. We identified two generations of individuals in which short stature and osteoporosis co-segregated with a mutation in ATP6V1H. Since V-ATPases are highly conserved between human and zebrafish, we generated loss-of-function mutants in atp6v1h in zebrafish through CRISPR/Cas9-mediated gene knockout. Homozygous mutant atp6v1h zebrafish exhibited a severe reduction in the number of mature calcified bone cells and a dramatic increase in the expression of mmp9 and mmp13. Heterozygous adults showed curved vertebra that lack calcified centrum structure and reduced bone mass and density. Treatment of mutant embryos with small molecule inhibitors of MMP9 and MMP13 significantly restored bone mass in the atp6v1h mutants. These studies have uncovered a new, ATP6V1H-mediated pathway that regulates bone formation, and defines a new mechanism of disease that leads to bone loss. We propose that MMP9/MMP13 could be therapeutic targets for patients with this rare genetic disease.

Osteoporosis, a major health problem worldwide, is characterized by low bone mineral density (BMD) and a propensity to fracture. Genetic factors are clearly the major determinants of BMD, but their identification and contribution to osteoporosis risk have been difficult to assess in humans. Genome-wide association studies (GWAS) have identified numerous sequence variants that influence BMD. The loci identified to date, however, account for only a small fraction of the total variation in BMD. Through analysis of a pedigree with an undiagnosed disease in which affected members have markedly low bone mass, we identify a novel and critical bone formation pathway, mediated through the gene ATP6V1H. Zebrafish lacking apt6vh1 demonstrate loss of bone mass, and exhibit increased mmp9 and mmp13 levels; inhibition of mmp9 and mmp13 led to the rescue of bone density defects. Here we show that happloinsufficiency of ATP6V1H is associated with osteoporosis in both humans and zebrafish. This study exemplifies the value of studying rare diseases to understand prevalent ones.

Bone: A Fertile Soil for Cancer Metastasis

Bone is one of the most common and most dangerous sites for metastatic growth across cancer types, and bone metastasis remains incurable. Unfortunately, the processes by which cancers preferentially metastasize to bone are still not well understood. In this review, we summarize the morphological features, physical properties, and cell signaling events that make bone a unique site for metastasis and bone remodeling. The signaling crosstalk between the tumor cells and bone cells begins a vicious cycle - a self-sustaining feedback loop between the tumor cells and the bone microenvironment composed of osteoclasts, osteoblasts, other bone marrow cells, bone matrix, and vasculature to support both tumor growth and bone destruction. Through this crosstalk, bone provides a fertile microenvironment that can harbor dormant tumor cells, sometimes for long periods, and support their growth by releasing cytokines as the bone matrix is destroyed, similar to providing nutrients for a seed to germinate in soil. However, few models exist to study the late stages of bone colonization by metastatic tumor cells. We describe some of the current methodologies used to study bone metastasis, highlighting the limitations of these methods and alternative future strategies to be used to study bone metastasis. While <i>in vivo</i> animal and patient studies may provide the gold standard for studying metastasis, <i>ex vivo</i> models can be used as an alternative to enable more controlled experiments designed to study the late stages of bone metastasis.

Current Evidence and Future Perspectives on HuR and Breast Cancer Development, Prognosis, and Treatment

Hu-antigen R (HuR) is an RNA-binding posttranscriptional regulator that belongs to the Hu/ELAV family. HuR expression levels are modulated by a variety of proteins, microRNAs, chemical compounds, or the microenvironment, and in turn, HuR affects mRNA stability and translation of various genes implicated in breast cancer formation, progression, metastasis, and treatment. The aim of the present review is to critically summarize the role of HuR in breast cancer development and its potential as a prognosticator and a therapeutic target. In this aspect, all the existing English literature concerning HuR expression and function in breast cancer cell lines, in vivo animal models, and clinical studies is critically presented and summarized. HuR modulates many genes implicated in biological processes crucial for breast cancer formation, growth, and metastasis, whereas the link between HuR and these processes has been demonstrated directly in vitro and in vivo. Additionally, clinical studies reveal that HuR is associated with more aggressive forms of breast cancer and is a putative prognosticator for patients' survival. All the above indicate HuR as a promising drug target for cancer therapy; nevertheless, additional studies are required to fully understand its potential and determine against which types of breast cancer and at which stage of the disease a therapeutic agent targeting HuR would be more effective.

MMP-13 is one of the critical mediators of the effect of HDAC4 deletion on the skeleton

Histone deacetylase 4 (Hdac4) regulates chondrocyte hypertrophy. Hdac4(-/-) mice are runted in size and do not survive to weaning. This phenotype is primarily due to the acceleration of onset of chondrocyte hypertrophy and, as a consequence, inappropriate endochondral mineralization. Previously, we reported that Hdac4 is a repressor of matrix metalloproteinase-13 (Mmp13) transcription, and the absence of Hdac4 leads to increased expression of MMP-13 both in vitro (osteoblastic cells) and in vivo (hypertrophic chondrocytes and trabecular osteoblasts). MMP-13 is thought to be involved in endochondral ossification and bone remodeling. To identify whether the phenotype of Hdac4(-/-) mice is due to up-regulation of MMP-13, we generated Hdac4/Mmp13 double knockout mice and determined the ability of deletion of MMP-13 to rescue the Hdac4(-/-) mouse phenotype. Mmp13(-/-) mice have normal body size. Hdac4(-/-)/Mmp13(-/-) double knockout mice are significantly heavier and larger than Hdac4(-/-) mice, they survive longer, and they recover the thickness of their growth plate zones. In Hdac4(-/-)/Mmp13(-/-) double knockout mice, alkaline phosphatase (ALP) expression and TRAP-positive osteoclasts were restored (together with an increase in Mmp9 expression) but osteocalcin (OCN) was not. Micro-CT analysis of the tibiae revealed that Hdac4(-/-) mice have significantly decreased cortical bone area compared with the wild type mice. In addition, the bone architectural parameter, bone porosity, was significantly decreased in Hdac4(-/-) mice. Hdac4(-/-)/Mmp13(-/-) double knockout mice recover these cortical parameters. Likewise, Hdac4(-/-) mice exhibit significantly increased Tb.Th and bone mineral density (BMD) while the Hdac4(-/-)/Mmp13(-/-) mice significantly recovered these parameters toward normal for this age. Taken together, our findings indicate that the phenotype seen in the Hdac4(-/-) mice is partially derived from elevation in MMP-13 and may be due to a bone remodeling disorder caused by overexpression of this enzyme.

Immunolocalization of MMP9 and MMP2 in osteolytic metastasis originating from MDA-MB-231 human breast cancer cells

The aim of the present study was to investigate the expression of matrix metalloproteinase (MMP)9 and MMP2, and their potential roles in bone metastasis nests using a well-standardized model of breast cancer bone metastasis in nude mice. BALB/c nu/nu mice (5-week-old; n=10) were subjected to intracardiac injection of MDA-MB-231 human breast cancer cells. After 4 weeks, the mice exhibiting radiolucent lesions in tibiae were sacrificed, and the tibiae were removed for histochemical analysis. The gene expression of MMP2 and MMP9 in the tumor cells, metaphysis and diaphysis of normal BALB/c nu/nu mice were determined using reverse transcription-polymerase chain reaction analysis. The metastatic tumor tissue occupied almost the entire bone marrow cavity. Numerous tartrate-resistant acid phosphatase-positive osteoclasts were found in the metastasized lesions. The invaded tumor cells positive for mammaglobin 1 exhibited different proliferation activities and apoptosis between the metaphysis and diaphysis. Proliferating cell nuclear antigen was expressed at high levels in the metaphyseal area, whereas TdT-mediated dUTP nick-end labeling (TUNEL)-positive cells were more evident in the diaphysis area. Of note, MMP9 was expressed predominantly in the proliferating cell nuclear antigen-positive area, whereas the expression of MMP2 was observed predominantly in the diaphysis, which had more TUNEL-positive cells. Taken together, the results suggested that MMP9 and MMP2 may have their own importance in extracellular matrix degradation and trabecular bone damage in different zones of bone metastasis, including the metaphysis and diaphysis.

Multiple myeloma-derived MMP-13 mediates osteoclast fusogenesis and osteolytic disease

Multiple myeloma (MM) cells secrete osteoclastogenic factors that promote osteolytic lesions; however, the identity of these factors is largely unknown. Here, we performed a screen of human myeloma cells to identify pro-osteoclastogenic agents that could potentially serve as therapeutic targets for ameliorating MM-associated bone disease. We found that myeloma cells express high levels of the matrix metalloproteinase MMP-13 and determined that MMP-13 directly enhances osteoclast multinucleation and bone-resorptive activity by triggering upregulation of the cell fusogen DC-STAMP. Moreover, this effect was independent of the proteolytic activity of the enzyme. Further, in mouse xenograft models, silencing MMP-13 expression in myeloma cells inhibited the development of osteolytic lesions. In patient cohorts, MMP-13 expression was localized to BM-associated myeloma cells, while elevated MMP-13 serum levels were able to correctly predict the presence of active bone disease. Together, these data demonstrate that MMP-13 is critical for the development of osteolytic lesions in MM and that targeting the MMP-13 protein - rather than its catalytic activity - constitutes a potential approach to mitigating bone disease in affected patients.

Protein Expression Profiling of Giant Cell Tumors of Bone Treated with Denosumab

Giant cell tumors of bone (GCTB) are locally aggressive osteolytic bone tumors. Recently, some clinical trials have shown that denosumab is a novel and effective therapeutic option for aggressive and recurrent GCTB. This study was performed to investigate the molecular mechanism underlying the therapeutic effect of denosumab. Comparative proteomic analyses were performed using GCTB samples which were taken before and after denosumab treatment. Each expression profile was analyzed using the software program to further understand the affected biological network. One of identified proteins was further evaluated by gelatin zymography and an immunohistochemical analysis. We identified 13 consistently upregulated proteins and 19 consistently downregulated proteins in the pre- and post-denosumab samples. Using these profiles, the software program identified molecular interactions between the differentially expressed proteins that were indirectly involved in the RANK/RANKL pathway and in several non-canonical subpathways including the Matrix metalloproteinase pathway. The data analysis also suggested that the identified proteins play a critical functional role in the osteolytic process of GCTB. Among the most downregulated proteins, the activity of MMP-9 was significantly decreased in the denosumab-treated samples, although the residual stromal cells were found to express MMP-9 by an immunohistochemical analysis. The expression level of MMP-9 in the primary GCTB samples was not correlated with any clinicopathological factors, including patient outcomes. Although the replacement of tumors by fibro-osseous tissue or the diminishment of osteoclast-like giant cells have been shown as therapeutic effects of denosumab, the residual tumor after denosumab treatment, which is composed of only stromal cells, might be capable of causing bone destruction; thus the therapeutic application of denosumab would be still necessary for these lesions. We believe that the protein expression patterns and the results of the network analysis will provide a better understanding of the effects of denosumab administration in patients with GCTB.