Matrix metalloproteinase-7 degrades all insulin-like growth factor binding proteins and facilitates insulin-like growth factor bioavailability

Hepatic prohibitin 1 and methionine adenosyltransferase α1 defend against primary and secondary liver cancer metastasis

BACKGROUND & AIMS

The liver is a common site of cancer metastasis, most commonly from colorectal cancer, and primary liver cancers that have metastasized are associated with poor outcomes. The underlying mechanisms by which the liver defends against these processes are largely unknown. Prohibitin 1 (PHB1) and methionine adenosyltransferase 1A (MAT1A) are highly expressed in the liver. They positively regulate each other and their deletion results in primary liver cancer. Here we investigated their roles in primary and secondary liver cancer metastasis.

METHODS

We identified common target genes of PHB1 and MAT1A using a metastasis array, and measured promoter activity and transcription factor binding using luciferase reporter assays and chromatin immunoprecipitation, respectively. We examined how PHB1 or MAT1A loss promotes liver cancer metastasis and whether their loss sensitizes to colorectal liver metastasis (CRLM).

RESULTS

Matrix metalloproteinase-7 (MMP-7) is a common target of MAT1A and PHB1 and its induction is responsible for increased migration and invasion when MAT1A or PHB1 is silenced. Mechanistically, PHB1 and MAT1A negatively regulate MMP7 promoter activity via an AP-1 site by repressing the MAFG-FOSB complex. Loss of MAT1A or PHB1 also increased MMP-7 in extracellular vesicles, which were internalized by colon and pancreatic cancer cells to enhance their oncogenicity. Low hepatic MAT1A or PHB1 expression sensitized to CRLM, but not if endogenous hepatic MMP-7 was knocked down first, which lowered CD4+ T cells while increasing CD8+ T cells in the tumor microenvironment. Hepatocytes co-cultured with colorectal cancer cells express less MAT1A/PHB1 but more MMP-7. Consistently, CRLM raised distant hepatocytes' MMP-7 expression in mice and humans.

CONCLUSION

We have identified a PHB1/MAT1A-MAFG/FOSB-MMP-7 axis that controls primary liver cancer metastasis and sensitization to CRLM.

IMPACT AND IMPLICATIONS

Primary and secondary liver cancer metastasis is associated with poor outcomes but whether the liver has underlying defense mechanism(s) against metastasis is unknown. Here we examined the hypothesis that hepatic prohibitin 1 (PHB1) and methionine adenosyltransferase 1A (MAT1A) cooperate to defend the liver against metastasis. Our studies found PHB1 and MAT1A form a complex that suppresses matrix metalloproteinase-7 (MMP-7) at the transcriptional level and loss of either PHB1 or MAT1A sensitizes the liver to metastasis via MMP-7 induction. Strategies that target the PHB1/MAT1A-MMP-7 axis may be a promising approach for the treatment of primary and secondary liver cancer metastasis.

Signaling Pathways of the Insulin-like Growth Factor Binding Proteins

The 6 high-affinity insulin-like growth factor binding proteins (IGFBPs) are multifunctional proteins that modulate cell signaling through multiple pathways. Their canonical function at the cellular level is to impede access of insulin-like growth factor (IGF)-1 and IGF-2 to their principal receptor IGF1R, but IGFBPs can also inhibit, or sometimes enhance, IGF1R signaling either through their own post-translational modifications, such as phosphorylation or limited proteolysis, or by their interactions with other regulatory proteins. Beyond the regulation of IGF1R activity, IGFBPs have been shown to modulate cell survival, migration, metabolism, and other functions through mechanisms that do not appear to involve the IGF-IGF1R system. This is achieved by interacting directly or functionally with integrins, transforming growth factor β family receptors, and other cell-surface proteins as well as intracellular ligands that are intermediates in a wide range of pathways. Within the nucleus, IGFBPs can regulate the diverse range of functions of class II nuclear hormone receptors and have roles in both cell senescence and DNA damage repair by the nonhomologous end-joining pathway, thus potentially modifying the efficacy of certain cancer therapeutics. They also modulate some immune functions and may have a role in autoimmune conditions such as rheumatoid arthritis. IGFBPs have been proposed as attractive therapeutic targets, but their ubiquity in the circulation and at the cellular level raises many challenges. By understanding the diversity of regulatory pathways with which IGFBPs interact, there may still be therapeutic opportunities based on modulation of IGFBP-dependent signaling.

Matrix Metalloproteinases Inhibitors in Cancer Treatment: An Updated Review (2013-2023)

Matrix metalloproteinases (MMPs) are identifiable members of proteolytic enzymes that can degrade a wide range of proteins in the extracellular matrix (ECM). MMPs can be categorized into six groups based on their substrate specificity and structural differences: collagenases, gelatinases, stromelysins, matrilysins, metalloelastase, and membrane-type MMPs. MMPs have been linked to a wide variety of biological processes, such as cell transformation and carcinogenesis. Over time, MMPs have been evaluated for their role in cancer progression, migration, and metastasis. Accordingly, various MMPs have become attractive therapeutic targets for anticancer drug development. The first generations of broad-spectrum MMP inhibitors displayed effective inhibitory activities but failed in clinical trials due to poor selectivity. Thanks to the evolution of X-ray crystallography, NMR analysis, and homology modeling studies, it has been possible to characterize the active sites of various MMPs and, consequently, to develop more selective, second-generation MMP inhibitors. In this review, we summarize the computational and synthesis approaches used in the development of MMP inhibitors and their evaluation as potential anticancer agents.

Insulin‐like growth factor‐2 is a promising candidate for the treatment and prevention of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. Current AD treatments slow the rate of cognitive decline, but do not restore lost function. One reason for the low efficacy of current treatments is that they fail to target neurotrophic processes, which are thought to be essential for functional recovery. Bolstering neurotrophic processes may also be a viable strategy for preventative treatment, since structural losses are thought to underlie cognitive decline in AD. The challenge of identifying presymptomatic patients who might benefit from preventative treatment means that any such treatment must meet a high standard of safety and tolerability. The neurotrophic peptide insulin-like growth factor-2 (IGF2) is a promising candidate for both treating and preventing AD-induced cognitive decline. Brain IGF2 expression declines in AD patients. In rodent models of AD, exogenous IGF2 modulates multiple aspects of AD pathology, resulting in (1) improved cognitive function; (2) stimulation of neurogenesis and synaptogenesis; and, (3) neuroprotection against cholinergic dysfunction and beta amyloid-induced neurotoxicity. Preclinical evidence suggests that IGF2 is likely to be safe and tolerable at therapeutic doses. In the preventative treatment context, the intranasal route of administration is likely to be the preferred method for achieving the therapeutic effect without risking adverse side effects. For patients already experiencing AD dementia, routes of administration that deliver IGF2 directly access the CNS may be necessary. Finally, we discuss several strategies for improving the translational validity of animal models used to study the therapeutic potential of IGF2.

IGF-Binding Proteins and Their Proteolysis as a Mechanism of Regulated IGF Release in the Nervous Tissue

Insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) play a key role in the maintenance of the nervous tissue viability. IGF-1 and IGF-2 exhibit the neuroprotective effects by stimulating migration and proliferation of nervous cells, activating cellular metabolism, inducing regeneration of damaged cells, and regulating various stages of prenatal and postnatal development of the nervous system. The availability of IGFs for the cells is controlled via their interaction with the IGF-binding proteins (IGFBPs) that inhibit their activity. On the contrary, the cleavage of IGFBPs by specific proteases leads to the IGF release and activation of its cellular effects. The viability of neurons in the nervous tissue is controlled by a complex system of trophic factors secreted by auxiliary glial cells. The main source of IGF for the neurons are astrocytes. IGFs can accumulate as an extracellular free ligand near the neuronal membranes as a result of proteolytic degradation of IGFBPs by proteases secreted by astrocytes. This mechanism promotes interaction of IGFs with their genuine receptors and triggers intracellular signaling cascades. Therefore, the release of IGF by proteolytic cleavage of IGFBPs is an important mechanism of neuronal protection. This review summarizes the published data on the role of IGFs and IGFBPs as the key players in the neuroprotective regulation with a special focus on the specific proteolysis of IGFBPs as a mechanism for the regulation of IGF bioavailability and viability of neurons.

Insulin-like growth factor binding protein 5: Diverse roles in cancer

Insulin-like growth factor binding proteins (IGFBPs) and the associated signaling components in the insulin-like growth factor (IGF) pathway regulate cell differentiation, proliferation, apoptosis, and adhesion. Of the IGFBPs, insulin-like growth factor binding protein 5 (IGFBP5) is the most evolutionarily conserved with a dynamic range of IGF-dependent and -independent functions, and studies on the actions of IGFBP5 in cancer have been somewhat paradoxical. In cancer, the IGFBPs respond to external stimuli to modulate disease progression and therapeutic responsiveness in a context specific manner. This review discusses the different roles of IGF signaling and IGFBP5 in disease with an emphasis on discoveries within the last twenty years, which underscore a need to clarify the IGF-independent actions of IGFBP5, the impact of its subcellular localization, the differential activities of each of the subdomains, and the response to elements of the tumor microenvironment (TME). Additionally, recent advances addressing the role of IGFBP5 in resistance to cancer therapeutics will be discussed. A better understanding of the contexts in which IGFBP5 functions will facilitate the discovery of new mechanisms of cancer progression that may lead to novel therapeutic opportunities.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

The tetrapartite synapse in neuropsychiatric disorders: Matrix metalloproteinases (MMPs) as promising targets for treatment and rational drug design

Inflammation and an exacerbated immune response are widely accepted contributing mechanisms to the genesis and progression of major neuropsychiatric disorders. However, despite the impressive advances in understanding the neurobiology of these disorders, there is still no approved drug directly linked to the regulation of inflammation or brain immune responses. Importantly, matrix metalloproteinases (MMPs) comprise a group of structurally related endopeptidases primarily involved in remodeling extracellular matrix (ECM). In the central nervous system (CNS), these proteases control synaptic plasticity and strength, patency of the blood-brain barrier, and glia-neuron interactions through cleaved and non-cleaved mediators. Several pieces of evidence have pointed to a complex scenario of MMPs dysregulation triggered by neuroinflammation. Furthermore, major psychiatric disorders' affective symptoms and neurocognitive abnormalities are related to MMPs-mediated ECM changes and neuroglia activation. In the past decade, research efforts have been directed to broad-spectrum MMPs inhibitors with frustrating clinical results. However, in the light of recent advances in combinatorial chemistry and drug design technologies, specific and CNS-oriented MMPs modulators have been proposed as a new frontier of therapy for regulating ECM properties in the CNS. Therefore, here we aim to discuss the state of the art of MMPs and ECM abnormalities in major neuropsychiatric disorders, namely depression, bipolar disorder, and schizophrenia, the possible neuro-immune interactions involved in this complex scenario of MMPs dysregulation and propose these endopeptidases as promising targets for rational drug design.

Lessons to Learn for Adequate Targeted Therapy Development in Metastatic Colorectal Cancer Patients

Insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase that regulates cell growth and proliferation. Upregulation of the IGF1R pathway constitutes a common paradigm shared with other receptor tyrosine kinases such as EGFR, HER2, and MET in different cancer types, including colon cancer. The main IGF1R signaling pathways are PI3K-AKT and MAPK-MEK. However, different processes, such as post-translational modification (SUMOylation), epithelial-to-mesenchymal transition (EMT), and microenvironment complexity, can also contribute to intrinsic and acquired resistance. Here, we discuss new strategies for adequate drug development in metastatic colorectal cancer patients.

Recent Advances in the Synthesis and Biological Activity of 8-Hydroxyquinolines

Compounds containing the 8-hydroxyquinoline (8-HQ) 1 nucleus exhibit a wide range of biological activities, including antimicrobial, anticancer, and antifungal effects. The chemistry and biology of this group have attracted the attention of chemists, medicinal chemists, and professionals in health sciences. A number of prescribed drugs incorporate this group, and numerous 8-HQ- based molecules can be used to develop potent lead compounds with good efficacy and low toxicity. This review focusses on the recent advances in the synthesis of 8-HQ derivatives with different pharmacological properties, including anticancer, antiviral, and antibacterial activities. For this purpose, recent relevant references were searched in different known databases and search engines, such as MEDLINE (PubMed), Google Scholar, Science Direct, Scopus, Cochrane, Scientific Information Database (SID), SciFinder, and Institute for Scientific Information (ISI) Web of Knowledge. This review article provides a literature overview of the various synthetic strategies and biological activities of 8-HQ derivatives and covers the recent related literature. Taken together, compounds containing the 8-HQ moiety have huge therapeutic value and can act as potential building blocks for various pharmacologically active scaffolds. In addition, several described compounds in this review could act leads for the development of drugs against numerous diseases including cancer.

The Multi-Faced Role of PAPP-A in Post-Partum Breast Cancer: IGF-Signaling is Only the Beginning

Insulin-like growth factor (IGF) signaling and control of local bioavailability of free IGF by the IGF binding proteins (IGFBP) are important regulators of both mammary development and breast cancer. A recent genome-wide association study (GWAS) identified small nucleotide polymorphisms that reduce the expression of IGFBP-5 as a risk factor of developing breast cancer. This observation suggests that genetic alterations leading to a decreased level of IGFBP-5 may also contribute to breast cancer. In the current review, we focus on Pregnancy-Associated Plasma Protein A (PAPP-A), a protease involved in the degradation of IGFBP-5. PAPP-A is overexpressed in the majority of breast cancers but its role in cancer has only begun to be explored. More specifically, this review aims at highlighting the role of post-partum involution in the oncogenic function of PAPP-A. Notably, we summarize recent studies indicating that PAPP-A plays a role not only in the degradation of IGFBP-5 but also in the deposition of collagen and activation of the collagen receptor discoidin 2 (DDR2) during post-partum involution. Finally, considering the immunosuppressive microenvironment of post-partum involution, we also discuss the unexpected finding made in Ewing Sarcoma that PAPP-A plays a role in immune evasion. While the immunosuppressive role of PAPP-A in breast cancer remains to be determined, collectively these studies highlight the multifaced role of PAPP-A in cancer that extends well beyond its effect on IGF-signaling.

Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3): Unraveling the Role in Mediating IGF-Independent Effects Within the Cell

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), one of the six members of the IGFBP family, is a key protein in the IGF pathway. IGFBP-3 can function in an IGF-dependent as well as in an IGF-independent manner. The IGF-dependent roles of IGFBP-3 include its endocrine role in the delivery of IGFs from the site of synthesis to the target cells that possess IGF receptors and the activation of associated downstream signaling. IGF-independent role of IGFBP-3 include its interactions with the proteins of the extracellular matrix and the proteins of the plasma membrane, its translocation through the plasma membrane into the cytoplasm and into the nucleus. The C-terminal domain of IGFBP-3 has the ability to undergo cell penetration therefore, generating a short 8-22-mer C-terminal domain peptides that can be conjugated to drugs or genes for effective intracellular delivery. This has opened doors for biotechnological applications of the molecule in molecular medicine. The aim of this this review is to summarize the complex roles of IGFBP-3 within the cell, including its mechanisms of cellular uptake and its translocation into the nucleus, various molecules with which it is capable of interacting, and its ability to regulate IGF-independent cell growth, survival and apoptosis. This would pave way into understanding the modus operandi of IGFBP-3 in regulating IGF-independent processes and its pleiotropic ability to bind with potential partners thus regulating several cellular functions implicated in metabolic diseases, including cancer.

Multiple Growth Factor Targeting by Engineered Insulin-like Growth Factor Binding Protein-3 Augments EGF Receptor Tyrosine Kinase Inhibitor Efficacy

Resistance to cancer therapy is a challenge because of innate tumor heterogeneity and constant tumor evolution. Since the pathway of resistance cannot be predicted, combination therapies may address this progression. We discovered that in addition to IGF1 and IGF2, IGFBP-3 binds bFGF, HGF, neuregulin, and PDGF AB with nanomolar affinity. Because growth factors drive resistance, simultaneous inhibition of multiple growth factor pathways may improve the efficacy of precision therapy. Growth factor sequestration by IGFBP-3-Fc enhances the activity of EGFR inhibitors by decreasing cell survival and inhibiting bFGF, HGF, and IGF1 growth factor rescue and also potentiates the activity of other cancer drugs. Inhibition of tumor growth in vivo with adjuvant IGFBP-3-Fc with erlotinib versus erlotinib after treatment cessation supports that the combination reduces cell survival. Inhibition of multiple growth factor pathways may postpone resistance and extend progression-free survival in many cancer indications.

Circulating insulin-like growth factor binding protein-3 and risk of gastrointestinal malignant tumors

BACKGROUND AND AIM

Insulin-like growth factor-1 (IGF1) is a potent mitogen and is inhibited by IGF-binding protein-3 (IGFBP3). High serum IGF1 and low IGFBP3 are associated with increased risk of several carcinomas. Here, we assessed the relationship of these peptides with the risk of gastrointestinal malignancies, in a prospective case-control study nested in the Japan Collaborative Cohort Study.

METHODS

The analysis involved 916 cases who had been diagnosed as gastrointestinal malignancies (C15-25) and 2306 controls. To estimate odds ratios for incidence of malignancies associated with these levels, a conditional logistic model was used.

RESULTS

Both higher total and free IGFBP3 were associated with a decreased risk of tumor (P for trend < 0.001 and = 0.003, respectively). People in the second to fifth quintiles had lower risk compared to the first quintile (odds ratios ranged 0.532-0.650 and 0.582-0.725, respectively). After adjustment for IGF1, body mass index, drinking, and smoking, total IGFBP3 was inversely correlated with cancer risk (P for trend = 0.031). After adjustment, free IGFBP3 was inversely associated with the risk (P for trend = 0.007). Although total IGF1 was inversely correlated with tumor risk, it was not after controlling for IGFBP3 (P for trend = 0.007 and 0.589, respectively). Free IGF1 was not associated with the risk (P for trend = 0.361). Limiting subjects to those followed for over 3 years reinforced the inverted relationships of total and free IGFBP3 with risk for tumors (P for trend = 0.005 and 0.008, respectively).

CONCLUSION

Both total and free IGFBP3 may be inversely associated with the incidence of gastrointestinal malignancies.

Decidual leucocytes infiltrating human spiral arterioles are rich source of matrix metalloproteinases and degrade extracellular matrix in vitro and in situ

PROBLEM

During pregnancy, the decidual spiral arterioles (SpAs) that supply maternal blood to the placenta undergo a series of changes to optimise the transfer of nutrients and oxygen to the developing foetus. Recent studies have shown that initiation of SpA transformation coincides with decidual leucocyte infiltration. Leucocytes are known to be a source of matrix metalloproteinases (MMPs); however, the complete profile of MMPs expressed by decidual NK cells (dNK) and macrophages has not been characterised. We hypothesised that leucocyte-derived MMPs contribute to SpA remodelling.

METHODS

Decidual NK cells and macrophages were isolated from first trimester decidua and their MMP repertoire profiled by qRT-PCR (n = 10; 5-11 weeks). Dual immunofluorescence was used to localise MMP expression in situ (n = 3; 5-12 weeks). Gelatin zymography was carried out to assess whether leucocyte-derived MMPs can degrade ECM. In situ zymography and immunofluorescence identified MMP activity in tissue-resident dNK and macrophages.

RESULTS

Decidual NK cells cells and macrophages expressed MMP2, -7, -9, -11, -16, -19 and tissue inhibitors of metalloproteinase-1, -2, and -3. Both cell types degraded gelatin using MMP2 and MMP9 and broke down collagen in an in vitro model of the SpA. Extravillous trophoblasts (EVTs) expressed a similar repertoire of MMPs.

CONCLUSION

We suggest that matrix remodelling in SpA is initiated by infiltrating leucocytes, while EVTs become involved at later stages.

A MMP7-sensitive photoclickable biomimetic hydrogel for MSC encapsulation towards engineering human cartilage

Cartilage tissue engineering strategies that use in situ forming degradable hydrogels for mesenchymal stem cell (MSC) delivery are promising for treating chondral defects. Hydrogels that recapitulate aspects of the native tissue have the potential to encourage chondrogenesis, permit cellular mediated degradation, and facilitate tissue growth. This study investigated photoclickable poly(ethylene glycol) hydrogels, which were tailored to mimic the cartilage microenvironment by incorporating extracellular matrix analogs, chondroitin sulfate and RGD, and crosslinks sensitive to matrix metalloproteinase 7 (MMP7). Human MSCs were encapsulated in the hydrogel, cultured up to nine weeks, and assessed by mRNA expression, protein production and biochemical analysis. Chondrogenic genes, SOX9, ACAN, and COL2A1, significantly increased with culture time, and the ratios of COL2A1:COL10A1 and SOX9:RUNX2 reached values of ∼20-100 by week 6. The encapsulated MSCs degraded the hydrogel, which was nearly undetectable by week 9. There was substantial deposition of aggrecan and collagen II, which correlated with degradation of the hydrogel. Minimal collagen X was detectable, but collagen I was prevalent. After week 1, extracellular matrix elaboration was accompanied by a ∼twofold increase in compressive modulus with culture time. The MMP7-sensitive cartilage mimetic hydrogel supported MSC chondrogenesis and promoted macroscopic neocartilaginous matrix elaboration representative of fibrocartilage. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2344-2355, 2018.

Differential Sensitivity of Human Hepatocellular Carcinoma Xenografts to an IGF-II Neutralizing Antibody May Involve Activated STAT3

Hepatocellular carcinoma (HCC) is highly refractory to current therapeutics used in the clinic. DX-2647, a recombinant human antibody, potently neutralizes the action of insulin-like growth factor-II (IGF-II), a ligand for three cell-surface receptors (IGF-IR, insulin receptor A and B isoforms, and the cation-independent mannose-6-phosphate receptor) which is overexpressed in primary human HCC. DX-2647 impaired the growth of tumor xenografts of the HCC cell line, Hep3B; however, xenografts of the HCC cell line, HepG2, were largely unresponsive to DX-2647 treatment. Analysis of a number of aspects of the IGF signaling axis in both cell lines did not reveal any significant differences between the two. However, while DX-2647 abolished phospho (p)-IGF-IR, p-IR and p-AKT signaling in both cell lines, HepG2 showed high levels of p-STAT3, which was unaffected by DX-2647 treatment and was absent from the Hep3B cell line. The driver of p-STAT3 was found to be a secreted cytokine, and treatment of HepG2 cells with a pan- JAK kinase inhibitor resulted in a loss of p-STAT3. These findings implicate the activation of STAT3 as one pathway that may mediate resistance to IGF-II-targeted therapy in HCC.

Coexpression of p-IGF-1R and MMP-7 Modulates Panitumumab and Cetuximab Efficacy in RAS Wild-Type Metastatic Colorectal Cancer Patients

INTRODUCTION

The coexpression of pIGF-1R and MMP-7 (double-positive phenotype, DP) correlates with poor overall survival (OS) in KRAS wild-type (WT) (exon 2) metastatic colorectal cancer (mCRC) patients treated with irinotecan-cetuximab in second/third line.

METHODS

We analyzed two prospective biomarker design trials of newly diagnosed RAS-WT mCRC patients treated with panitumumab-FOLFOX6 (PULSE trial; NCT01288339) or cetuximab plus either FOLFOX6/FOLFIRI (POSIBA trial; NCT01276379). The main exposure was DP phenotype (DP/non-DP), as assessed by two independent pathologists. DP cases were defined by immunohistochemistry as >70% expression of moderate or strong intensity for both MMP-7 and pIGF-1R. Primary endpoint: progression-free survival (PFS); secondary endpoints: OS and response rate. PFS and OS were adjusted by baseline characteristics using multivariate Cox models.

RESULTS

We analyzed 67 patients (30 non-DP, 37 DP) in the PULSE trial and 181 patients in the POSIBA trial (158 non-DP, 23 DP). Response rates and PFS were similar between groups in both studies. DP was associated with prolonged OS in PULSE (adjusted HR: 0.23; 95%CI: 0.11-0.52; P=.0004) and with shorter OS in POSIBA (adjusted HR: 1.67; 95%CI: 0.96-2.90; P=.07).

CONCLUSION

A differential effect of anti-EGFRs on survival by DP phenotype was observed. Panitumumab might be more beneficial for RAS-WT mCRC patients with DP phenotype, whereas cetuximab might improve OS in non-DP.

AIMP2-DX2 Promotes the Proliferation, Migration, and Invasion of Nasopharyngeal Carcinoma Cells

Nasopharyngeal carcinoma (NPC) is a head and neck tumor with high degree of malignancy and with high incidence especially in southern China. AIMP2-DX2, one isoform of the aminoacyl-tRNA synthetase interacting multifunctional proteins (AIMPs), is shown to be a potential target in many cancers. However, the detailed mechanisms of AIMP2-DX2 in NPC development remain to be elucidated. Here, we found that the mRNA expression level of AIMP2-DX2 was significantly increased in NPC specimens, compared with normal nasopharyngeal tissues. Microarray immunohistochemical analysis of NPC specimens and Kaplan–Meier analysis showed that patients with high AIMP2-DX2 protein expression had shorter overall survival than those with low AIMP2-DX2 level. Furthermore, mRNA and protein expression levels of AIMP2-DX2 were both increased in cultured NPC cell lines (5-8F, CNE-2Z, and CNE-1), by being compared with normal nasopharyngeal cell line NP69. Overexpression of AIMP2-DX2 remarkably promoted the cell viability, cell migration, and invasion of cultured NPC cells. Genetic knockdown of AIMP2-DX2 by shRNA lentiviruses significantly suppressed the proliferation, migration, and invasion and induced apoptosis of NPC cells. Inhibition of AIMP2-DX2 decreased the highly expressed level of matrix metalloproteinase- (MMP-) 2 and MMP-9, further suppressed proliferation, migration, and invasion in cultured NPC cells in vitro, and inhibited tumor growth in a xenograft mouse model in vivo. Taken together, these results suggest that AIMP2-DX2 plays an important role in the regulation of NPC and could be a potential therapeutic target and prognostic indicator for the treatment of NPC.

Strategies to Target Matrix Metalloproteinases as Therapeutic Approach in Cancer

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are capable of degrading numerous extracellular matrix (ECM) components thus participating in physiological and pathological processes. Apart from the remodeling of ECM, they affect cell-cell and cell-matrix interactions and are implicated in the development and progression of various diseases such as cancer. Numerous studies have demonstrated that MMPs evoke epithelial to mesenchymal transition (EMT) of cancer cells and affect their signaling, adhesion, migration and invasion to promote cancer cell aggressiveness. Various studies have suggested MMPs as suitable targets for treatment of malignancies, and several MMP inhibitors (MMPIs) have been developed. Although initial trials have failed to establish MMPIs as anticancer agents due to lack of specificity and side effects, new MMPIs have been developed with improved action that are currently being investigated. Furthermore, novel strategies that target MMPs for improving drug delivery and regulating their activity in tumors are presented. This review summarizes the implication of MMPs in cancer progression and discusses the advancements in their targeting.

Influence of Immune Myeloid Cells on the Extracellular Matrix During Cancer Metastasis

The extracellular matrix (ECM) is one of the most important components within the tumor microenvironment that supports cancer development and metastasis. Under normal physiological conditions, the ECM is a tightly regulated network providing structural and biochemical support. However, the ECM becomes highly disorganized during neoplastic progression and consequently, stimulates cancer cell transformation, growth and spread. Cancer development and progression is also known to greatly benefit from the support of immune myeloid cells, which have multiple pro-tumorigenic functions including promoting tumor growth, migration and invasion, stimulating angiogenesis and suppressing anti-tumor responses. An increasing number of studies have shown that myeloid cells alter the ECM to support metastatic cancer progression and in turn, the ECM can influence the function of infiltrating myeloid cells. However, the exact nature of this relationship, such as the mechanisms employed and their molecular targets remains unclear. This review discusses evidence for the reciprocal dependence of myeloid cells and the tumor ECM for efficient tumor development and explores potential mechanisms involved in these interactions. A better understanding of this relationship has exciting implications for the development of new therapeutic treatments for metastatic cancer.

Targeting Insulin-Like Growth Factor Binding Protein-3 Signaling in Triple-Negative Breast Cancer

Insulin-like growth factor binding protein-3 (IGFBP-3) is a key regulatory molecule of the IGF axis and can function in a tissue-specific way as both a tumor suppressor and promoter. Triple-negative breast cancer (TNBC) has high tumor expression of IGFBP-3 associated with markers of poor prognosis and, although accounting for 15-20% of all breast cancers, is responsible for disproportionate rates of morbidity and mortality. Because they lack estrogen and progesterone receptors and overexpression of HER2, TNBC are resistant to treatments that target these molecules, making the development of new therapies an important goal. In addition to frequent high expression of IGFBP-3, these tumors also express EGFR highly, but targeting EGFR signaling alone in TNBC has been of little success. Identification of a functional growth-stimulatory interaction between EGFR and IGFBP-3 signaling prompted investigation into cotargeting these pathways as a novel therapy for TNBC. This involves inhibition of both EGFR kinase activity and a mediator of IGFBP-3's stimulatory bioactivity, sphingosine kinase-1 (SphK1), and has shown promise in a preclinical setting. Functional interaction between EGFR and IGFBP-3 may also promote chemoresistance in TNBC, and delineating the mechanisms involved may identify additional targets for development of therapies in cancers that express both IGFBP-3 and EGFR.

Relevance of IGFBP2 proteolysis in glioma and contribution of the extracellular protease ADAMTS1

Expression of IGFBP2 (Insulin-like Growth Factor Binding Protein 2) has been positively correlated with glioma progression. Although the proteolysis of IGFBP2 has been widely recognized, with consequences as a major modulator of IGFII signaling, the relevance of this post-translational modification has not been well studied in tumors. Using an in vivo proteomic approach by Isotope-Coded Protein Label (ICPL), we identified IGFBP2 as a target of the extracellular protease ADAMTS1 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 1). Notably, the proteolytic pattern of IGFBP2 was also detected in human glioma culture cells and, more importantly, in all glioma samples evaluated. In addition, high expression of ADAMTS1 correlates with higher levels of cleaved IGFBP2 in glioblastoma multiforme cases. Using gene expression public databases, we confirmed that IGFBP2 is a poor prognosis marker for gliomas, and we also observed an important contribution of ADAMTS1.Finally, we showed the impact of ADAMTS1 on IGFII-mediated IGF1R phosphorylation and cellular migration. Our results support a functional interaction between IGFBP2 and ADAMTS1 and suggest the need to evaluate post-translational modifications of IGFBP2 in glioma, in order to approach new therapies.

Recent insights into the actions of IGFBP-6

IGFBP-6 is an O-linked glycoprotein that preferentially binds IGF-II over IGF-I. It is a relatively selective inhibitor of IGF-II actions including proliferation, survival and differentiation of a wide range of cells. IGFBP-6 has recently been shown to have a number of IGF-independent actions, including promotion of apoptosis in some cells and inhibition of angiogenesis. IGFBP-6 also induces migration of tumour cells including rhabdomyosarcomas by an IGF-independent mechanism. This chemotactic effect is mediated by MAP kinases. IGFBP-6 binds to prohibitin-2 on the cell surface and the latter is required for IGFBP-6-induced migration by a mechanism that is independent of MAP kinases. IGFBP-6 may enter the nucleus and modulate cell survival and differentiation. IGFBP-6 expression is decreased in a number of cancer cells and it has been postulated to act as a tumour suppressor. IGFBP-6 expression is increased in a smaller number of cancers, which may reflect a compensatory mechanism to control IGF-II actions or IGF-independent actions. The relative balance of IGF-dependent and IGF-independent actions of IGFBP-6 in vivo together with the related question regarding the roles of IGFBP-6 binding to IGF and non-IGF ligands are keys to understanding the physiological role of this protein.

Column chromatographic characterization of complex formation of pro-IGF-II isoforms with acid labile subunit and IGF-binding proteins associated with non-islet cell tumour induced hypoglycaemia

OBJECTIVE AND DESIGN

Non-islet cell tumour induced hypoglycaemia (NICTH) is a paraneoplastic phenomenon that is associated with the formation of several isoforms of pro-insulin like growth factor 2 (pro-IGF-II), or so called "big" IGF-II. Disturbance of ternary complex formation by big IGF-II is assumed to be a crucial early event in the pathogenic cascade of hypoglycaemia. By size-exclusion chromatography, we investigated complex formation by adding different naturally occurring isoforms of pro-IGF-II to pooled normal adult serum. Results were compared with the analysis of the serum from a patient with NICTH.

RESULTS

Gel filtration experiments with the serum of a patient with NICTH demonstrated that ternary complex formation was severely compromised. The various forms of pro-IGF-II did not induce a shift of IGF-binding protein 3 (IGFBP-3) from 150kD towards smaller binary complexes in the normal adult serum, suggesting that they did not interfere with the interaction between the acid labile subunit and IGFBP-3. Instead, unglycosylated recombinant pro-IGF-II[1-104] was capable of forming a 150kD complex. In contrast, predominantly glycosylated and unglycosylated pro-IGF-II[1-87] eluted in the free unbound form. We showed that mature IGF-II and isoforms of pro-IGF-II were able to phosphorylate the IGF-I receptors of MC7 cells, albeit to a markedly lesser extent than IGF-I. When the patient's serum was tested in this system, the IGF-I receptor phosphorylation activity was considerably less than that in sera from age matched healthy individuals.

CONCLUSION

We postulate that, alongside the presence of big IGF-II in the circulation, additional steps are required to stimulate the release of IGF-II and pro-IGF-II isoforms from IGFBPs in vivo. These factors may be proteases, that are present in the local environment of the tumour and in insulin-sensitive tissues.

Inhibition of tumor-associated αvβ3 integrin regulates the angiogenic switch by enhancing expression of IGFBP-4 leading to reduced melanoma growth and angiogenesis in vivo

A more complete understanding of the mechanisms that regulate the angiogenic switch, which contributes to the conversion of small dormant tumors to actively growing malignancies, is important for the development of more effective anti-angiogenic strategies for cancer therapy. While significant progress has been made in understanding the complex mechanisms by which integrin αvβ3 expressed in endothelial cells governs angiogenesis, less is known concerning the ability of αvβ3 expressed within the tumor cell compartment to modulate the angiogenic output of a tumor. Here we provide evidence that αvβ3 expressed in melanoma cells may contribute to the suppression of IGFBP-4, an important negative regulator of IGF-1 signaling. Given the multiple context-dependent roles for αvβ3 in angiogenesis and tumor progression, our novel findings provide additional molecular insight into how αvβ3 may govern the angiogenic switch by a mechanism associated with a p38 MAPK and matrix metalloproteinases-dependent regulation of the endogenous angiogenesis inhibitor IGFBP-4.

Expression and activity levels of matrix metalloproteinase-7 and in situ localization of caseinolytic activity in colorectal cancer

OBJECTIVES

Matrix metalloproteinase-7 is capable of degrading several ECM and non-ECM molecules and contributes to colorectal cancer progression and metastasis. Here, we examined the significance of MMP-7 in colorectal tumors by detecting active and latent MMP-7 levels and localization of its caseinolytic activity.

DESIGN AND METHODS

We investigated expression levels, localization, and proteolytic activity of MMP-7 and local caseinolytic activity in colorectal tumor and paired normal tissues by using real time PCR, casein zymography, immunohistochemistry and in situ casein zymography, respectively. In addition the results were compared with clinicopathological variables.

RESULTS

Real time PCR and immunohistochemistry showed that MMP-7 expressions were higher in colorectal tumor tissues than in normal tissues. Also, mRNA expressions of MMP-7 were positively correlated with tumor and pathological stages and negatively correlated with age. Furthermore, MMP-7 mRNA expression had a sensitivity of 81.3% and a specificity of 81.2% at a cut-off value of 0.0006, making it a potential marker for diagnosis of colorectal cancer. According to casein zymography, pro- and active MMP-7 levels were also elevated in tumor tissues. In addition, we assessed local caseinolytic activity using in situ casein zymography. Increased immunoreactivity of MMP-7 and local caseinolytic activity were found in neoplastic cells but not in stromal cells.

CONCLUSION

We emphasized the significant role of MMP-7 in diagnosis and progression and/or development of colorectal cancer.

Cell-mediated degradation regulates human mesenchymal stem cell chondrogenesis and hypertrophy in MMP-sensitive hyaluronic acid hydrogels

Photocrosslinked methacrylated hyaluronic acid (MeHA) hydrogels support chondrogenesis of encapsulated human mesenchymal stem cells (hMSCs). However, the covalent crosslinks formed via chain polymerization in these hydrogels are hydrolytically non-degradable and restrict cartilage matrix spatial distribution and cell spreading. Meanwhile, cells are known to remodel their surrounding extracellular matrix (ECM) by secreting catabolic enzymes, such as MMPs. Hydrogels that are created with bifunctional crosslinkers containing MMP degradable peptide sequences have been shown to influence hMSC differentiations. However, crosslinks formed in the MMP-degradable hydrogels of these previous studies are also prone to hydrolysis, thereby confounding the effect of MMP-mediated degradation. The objective of this study is to develop a MMP-sensitive but hydrolytically stable hydrogel scaffold and investigate the effect of MMP-mediated hydrogel degradation on the chondrogenesis of the encapsulated hMSCs. Hyaluronic acid macromers were modified with maleimide groups and crosslinked with MMP-cleavable peptides or control crosslinkers containing dual thiol groups. The chondrogenesis of the hMSCs encapsulated in the hydrolytically stable MMP-sensitive HA hydrogels were compared with that of the MMP-insensitive HA hydrogels. It was found that hMSCs encapsulated in the MMP-sensitive hydrogels switched to a more spreaded morphology while cells in the MMP-insensitive hydrogels remained in round shape. Furthermore, hMSCs in the MMP-sensitive hydrogels expressed higher level of chondrogenic marker genes but lower level of hypertrophic genes compared to cells in the MMP-insensitive hydrogels. As a result, more cartilage specific matrix molecules but less calcification was observed in the MMP-degradable hydrogels than in the MMP-insensitive hydrogels. Findings from this study demonstrate that cell-mediated scaffold degradation regulates the chondrogenesis and hypertrophy of hMSCs encapsulated in HA hydrogels.

IGF binding proteins in cancer: mechanistic and clinical insights

The six members of the family of insulin-like growth factor (IGF) binding proteins (IGFBPs) were originally characterized as passive reservoirs of circulating IGFs, but they are now understood to have many actions beyond their endocrine role in IGF transport. IGFBPs also function in the pericellular and intracellular compartments to regulate cell growth and survival - they interact with many proteins, in addition to their canonical ligands IGF-I and IGF-II. Intranuclear roles of IGFBPs in transcriptional regulation, induction of apoptosis and DNA damage repair point to their intimate involvement in tumour development, progression and resistance to treatment. Tissue or circulating IGFBPs might also be useful as prognostic biomarkers.

Matrix metalloproteinases in pneumonia

Pneumonia is a worldwide infectious disease that is associated with significant morbidity and mortality and is the most common fatal infection acquired in hospitals. Despite advances in preventive strategies, such as antibiotic therapies and intensive care, the mortality rate still requires substantial improvement. Matrix metalloproteinases (MMPs) are a large family of zinc-dependent endopeptidases, which are known as the major enzymes responsible for the proteolytic degradation of proteinaceous components of the extracellular matrix (ECM). Although the main function of MMPs is the removal of the ECM during tissue resorption and progression of various diseases, MMPs also interact with multiple cytokines, participating in the pathology of infection and inflammation. This review presents a schematic overview of the different MMPs expressed in pneumonia. MMPs are key factors in the pathogenesis of various types of pneumonia, such as community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia. Here, we review the pathological roles of various MMPs in pneumonia.

MMP7 and MMP8 genetic polymorphisms in bladder cancer patients

Introduction

Breakdown of the extracellular matrix by matrix metalloproteinases (MMPs), as we know, is one of mechanisms involved and required in tumor invasion. MMP7 is a negative prognostic factor of various malignances, while MMP8 exhibits an inhibitory effect on tumorigenesis and metastasis. We evaluated the potential association of functional polymorphisms in the promoter of the MMP7 (rs11568818) and MMP8 (rs11225395) genes and bladder cancer (BCa) risk.

Materials and methods

The study included 241 BCa cases and 199 healthy population controls that were collected at the First Department of Urology, Medical University (Łódź, Poland) and at the Nofer Institute of Occupational Medicine (Łódź, Poland). Genomic DNA samples were isolated from venous blood and genetic polymorphisms were analyzed by real–time polymerase chain reaction using TaqMan fluorescent probes. Associations between genotype and allele status were estimated by logistic regression models adjusted for classic risk factors (e.g. age, gender and cigarette smoking).

Results

MMP7 and MMP8 genotypes were distributed similarly in BCa patients and in controls and at least one variant allele was not associated with BCa cancer risk (OR, 0.91; 95% CI, 0.60–1.39; p = 0.662 for MMP7 and OR, 0.96; 95% CI, 0.63–1.46; p = 0.836 for MMP8). We observed higher prevalence of MMP7 GG genotypes among BCa patients than in controls (OR, 1.54; 95% CI, 0.93–2.55; p = 0.093). Additionally, genetic polymorphisms in the MMP7 and MMP8 were not associated with the tumor grade or stage.

Conclusions

Our results suggest that genetic variations in two genes encoding members of the MMP7 and MMP8 are not associated with a risk of BCa in the Caucasian population.

Insulin-like growth factor-binding protein-6 and cancer

The IGF (insulin-like growth factor) system is essential for physiological growth and it is also implicated in a number of diseases including cancer. IGF activity is modulated by a family of high-affinity IGF-binding proteins, and IGFBP-6 is distinctive because of its marked binding preference for IGF-II over IGF-I. A principal role for IGFBP-6 is inhibition of IGF-II actions, but recent studies have indicated that IGFBP-6 also has IGF-independent effects, including inhibition of angiogenesis and promotion of cancer cell migration. The present review briefly summarizes the IGF system in physiology and disease before focusing on recent studies on the regulation and actions of IGFBP-6, and its potential roles in cancer cells. Given the widespread interest in IGF inhibition in cancer therapeutics, increasing our understanding of the mechanisms underlying the actions of the IGF ligands, receptors and binding proteins, including IGFBP-6, will enhance our ability to develop optimal treatments that can be targeted to the most appropriate patients.

Biochemical characterization of individual human glycosylated pro-insulin-like growth factor (IGF)-II and big-IGF-II isoforms associated with cancer

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed "pro" and "big" IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling.

Plasma matrix metalloproteinases and postmenopausal breast cancer risk: a nested case-control study in the Multiethnic Cohort study

The survival of malignant breast cells depends upon the remodeling of the extracellular matrix, including complex interactions with matrix metalloproteinases (MMPs). It has been hypothesized that circulating MMPs may serve as early indicators of breast cancer development in hospital-based case-control studies. A nested case-control study of the association of pre-diagnostic plasma levels of MMPs with the subsequent risk of postmenopausal breast cancer was conducted within the Multiethnic Cohort. During the follow-up period, 713 women with incident invasive breast cancer were identified and individually (1:1) matched to controls. Four types of MMPs (1, 2, 3, and 7) were analyzed by microsphere immunofluorescence assay. Mean plasma levels of MMPs did not differ significantly between cases and controls; nor were there differences in breast cancer risk by MMP level. No difference in the risk of breast cancer by plasma level of the MMPs was found within strata of age, or ethnicity, although MMP-1 levels were positively associated with breast cancer risk in obese women and women by hormone replacement medications (P values for interaction <0.05). Few significant differences in risk by levels of the MMPs were found by any of the clinical variables. Circulating MMPs were not associated with postmenopausal breast cancer risk.

Extended spectrum of human glucose-6-phosphatase catalytic subunit 3 deficiency: novel genotypes and phenotypic variability in severe congenital neutropenia

OBJECTIVE

To delineate the phenotypic and molecular spectrum of patients with a syndromic variant of severe congenital neutropenia (SCN) due to mutations in the gene encoding glucose-6-phosphatase catalytic subunit 3 (G6PC3).

STUDY DESIGN

Patients with syndromic SCN were characterized for associated malformations and referred to us for G6PC3 mutational analysis.

RESULTS

In a cohort of 31 patients with syndromic SCN, we identified 16 patients with G6PC3 deficiency including 11 patients with novel biallelic mutations. We show that nonhematologic features of G6PC3 deficiency are good predictive indicators for mutations in G6PC3. Additionally, we demonstrate genetic variability in this disease and define novel features such as growth hormone deficiency, genital malformations, disrupted bone remodeling, and abnormalities of the integument. G6PC3 mutations may be associated with hydronephrosis or facial dysmorphism. The risk of transition to myelodysplastic syndrome/acute myeloid leukemia may be lower than in other genetically defined SCN subgroups.

CONCLUSIONS

The phenotypic and molecular spectrum in G6PC3 deficiency is wider than previously appreciated. The risk of transition to myelodysplastic syndrome or acute myeloid leukemia may be lower in G6PC3 deficiency compared with other subgroups of SCN.

Matrilysin (MMP-7) inhibition of BMP-7 induced renal tubular branching morphogenesis suggests a role in the pathogenesis of human renal dysplasia

Congenital renal dysplasia (RD) is a severe form of congenital renal malformation characterized by disruption of normal renal development with cyst formation, reduced or absent nephrons, and impaired renal growth. The authors previously identified that matrilysin (matrix metalloproteinase-7) was overexpressed in a microarray gene expression analysis of human RD compared to normal control kidneys. They now find that active matrilysin gene transcription and protein synthesis occur within dysplastic tubules and epithelial cells lining cysts in human RD by RT-PCR and immunohistochemistry. Similar staining patterns were seen in obstructed kidneys of pouch opossums that show histological features similar to that of human RD. In vitro, matrilysin inhibits formation of branching structures in mIMCD-3 cells stimulated by bone morphogenetic protein-7 (BMP-7) but does not inhibit hepatocyte growth factor-stimulated branching. BMP-7 signaling is essential for normal kidney development, and overexpression of catalytically active matrilysin in human embryonic kidney 293 cells reduces endogenous BMP-7 protein levels and inhibits phosphorylation of BMP-7 SMAD signaling intermediates. These findings suggest that matrilysin expression in RD may be an injury response that disrupts normal nephrogenesis by impairing BMP-7 signaling.

Insulin-like growth factor receptor expression is associated with aggressive phenotypes and has therapeutic activity in biliary tract cancers

Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for carcinogenicity and progression of several cancers but the function of this pathway and its utility as a therapeutic target have not been studied comprehensively in biliary tract carcinomas (BTC). We investigated the immunohistochemical expression of elements of the IGF axis, matrilysin, overexpression of p53 and the methylation status of the IGFBP-3 promoter in 80 surgically resected BTC. We also assessed the effect of IGF-IR blockade on signal transduction, proliferation and survival in three BTC cell lines using a new tyrosine kinase inhibitor, BMS-536924, and dominant negative IGF-IR (IGF-IR/dn). The effects of IGF-IR blockade was also studied in nude mouse xenograft models. IGF-I was expressed in 60% and IGF-II in 50% of tumors. High expression was associated with tumor size. IGF-IR was expressed in 69% of the cases and was associated with advanced stage and matrilysin expression. Hypermethylation of the IGFBP-3 promoter was detected in 41% of BTC and was inversely correlated with p53 expression. BMS-536924 blocked autophosphorylation of IGF-IR and both Akt and ERK activation by both IGF-I and insulin. BMS-536924 suppressed proliferation and tumorigenicity in vitro in a dose-dependent fashion. This inhibitor upregulated chemotherapy-induced apoptosis in a dose-dependent fashion. Moreover, IGF-IR blockade was effective against tumors in mice. IGF-IR might identify a subset of BTC with a particularly aggressive phenotype and is a candidate therapeutic target in this disease. BMS-536924 might have significant therapeutic utility.

Multiple antitumor effects of picropodophyllin in colon carcinoma cell lines: clinical implications

Although colorectal cancer can be successfully treated by conventional strategies such as chemo/radiotherapy and surgery, a substantial number of cases, in particular those with liver metastases, remain incurable. Therefore, novel treatment approaches are warranted. The IGF-1R and its ligands, mainly IGF-1 and IGF-2, have been suggested to play pivotal roles in proliferation, survival and migration of adenocarcinoma cells of the colon/rectum. Therefore, interference with IGF-1R-mediated signaling may represent a therapeutic option for this malignancy. In this study, semi-quantitative RT-PCR analyses of 48 paired, colorectal cancer patient samples showed significant overexpression of tumor IGF-1R and IGF-2 mRNA. There was also an overexpression of MMP-7, which was significantly correlated with histopathological parameters. Based on these findings, the effect of the IGF-1R-inhibitory cyclolignan picropodophyllin (PPP) was assessed in the four colon carcinoma cell lines HT-29, HCT-116, DLD-1 and CaCO-2. PPP strongly and dose-dependently inhibited proliferation and migration in all cell lines. However, when exposed to 0.5 μM PPP, only HT-29 showed a net decrease of viable cells as compared with the cell number at the beginning of the experiment, a finding that coincided with decreased expression/phosphorylation of IGF-1R, AKT and ERK. This cell line also exhibited PPP-induced downregulation of MMP-7 and MMP-9. Similar to the DLD-1 and HCT-116 cell lines, HT-29 also showed substantial cell detachment in response to PPP. Although a net reduction of cells by PPP seems to require a synchronized downregulation of IGF-1R, AKT and ERK1/2, part of the antitumor effect may be explained by other, possibly IGF-1R-unrelated mechanism(s). Such a multitude of inhibitory effects of PPP in colon cancer cells together with its low toxicity in vivo makes it a promising drug candidate in the treatment of this disease.

Analysis of Expression Profile of Gene Encoding Proteins of Signal Cascades Activated by Insulin-like Growth Factors in Colorectal Cancer

The aim of the study is to analyse gene typing with the use of the microarray technique (HG-U133A, Affymetrix), differentiating colorectal cancer tissues from tissues assessed histopathologically as healthy ones among a panel of 93 mRNA of gene encoding proteins involved in the activation of cellular signal transduction pathways by insulin-like growth factors. The study was conducted on a group of 8 colorectal cancer patients. Frozen tumor and healthy specimens from the patients were used in molecular tests. Transcript IGF2 differentiated cancer from healthy tissue. Among the genes participating in the cascade of signal transfer in cells activated by IGF, GRB10, PIK3R3, PIK3R1, and IRSI were qualified as differentiating transcripts. IRSI indicated over-expression in tumour. Transcript SMAD2 showed a significant changed in tumour samples (increased expression).

The efficacy of IGF-I receptor monoclonal antibody against human gastrointestinal carcinomas is independent of k-ras mutation status

PURPOSE

Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for carcinogenicity and proliferation of gastrointestinal cancers. We have previously shown successful targeting therapy for colorectal, pancreatic, gastric, and esophageal carcinomas using recombinant adenoviruses expressing dominant negative IGF-IR. Mutation in k-ras is one of key factors in gastrointestinal cancers. In this study, we sought to evaluate the effect of a new monoclonal antibody for IGF-IR, figitumumab (CP-751,871), on the progression of human gastrointestinal carcinomas with/without k-ras mutation.

EXPERIMENTAL DESIGN

We assessed the effect of figitumumab on signal transduction, proliferation, and survival in six gastrointestinal cancer cell lines with/without k-ras mutation, including colorectal and pancreatic adenocarcinoma, esophageal squamous cell carcinoma, and hepatoma. Combination effects of figitumumab and chemotherapy were also studied. Then figitumumab was evaluated in the treatment of xenografts in nude mice.

RESULTS

Figitumumab blocked autophosphorylation of IGF-IR and its downstream signals. The antibody suppressed proliferation and tumorigenicity in all cell lines. Figitumumab inhibited survival by itself and up-regulated chemotherapy (5-FU and gemcitabine) induced apoptosis. Moreover, the combination of this agent and chemotherapy was effective against tumors in mice. The effect of figitumumab was not influenced by the mutation status of k-ras. Figitumumab reduced expression of IGF-IR but not insulin receptor in these xenografted tumors. The drug did not affect murine body weight or blood concentrations of glucose, insulin, IGF binding protein 3, and growth hormone.

CONCLUSIONS

IGF-IR might be a good molecular therapeutic target and figitumumab may thus have therapeutic value in human gastrointestinal malignancies even in the presence of k-ras mutations.

Matrix metalloproteinases and their clinical relevance in urinary bladder cancer

Matrix metalloproteinases (MMPs) have important roles in several cancer-supporting cellular processes, such as extracellular matrix (ECM) remodeling, angiogenesis, apoptosis, epithelial-to-mesenchymal transition and cell proliferation. This broad range of activity has led to considerable interest in the use of MMPs in the clinical setting as diagnostic or prognostic biomarkers and as therapeutic targets. Levels of the different MMPs can be measured in several sample types, including paraffin-embedded or fresh frozen tissue, serum, plasma and urine, and by various analytical methodologies, such as immunohistochemistry, real-time PCR, western and northern blot analyses, enzyme-linked immunosorbent assay and zymography. Several MMPs have been identified as having potential diagnostic or prognostic utility, whether alone or in combination with currently available diagnostic tests or imaging modalities. Although the early broad-spectrum anti-MMP agents showed a lack of efficacy, our continually improving understanding of the complex physiologic and pathologic roles of MMPs might enable the development of new MMP-specific and tumor-specific therapies. Accordingly, MMPs will continue to be the subjects of intensive research in bladder cancer.

Sexually dimorphic diet-induced insulin resistance in obese tissue inhibitor of metalloproteinase-2 (TIMP-2)-deficient mice

Circulating levels of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitor of metalloproteinases (TIMPs), are altered in human obesity and may contribute to its pathology. TIMP-2 exerts MMP-dependent (MMP inhibition and pro-MMP-2 activation) and MMP-independent functions. To assess the role of TIMP-2 in a murine model of nutritionally induced obesity, weight gain in wild-type and TIMP-2 deficient [knockout (KO)] mice fed a chow or high-fat diet (HFD) was determined. The effects of diet on glucose tolerance and insulin sensitivity, as well as pancreatic β-cell and adipocyte physiology, were assessed. Chow-fed TIMP-2 KO mice of both sexes became obese but maintained relatively normal glucose tolerance and insulin sensitivity. Obesity was exacerbated on the HFD. However, HFD-fed male, but not female, TIMP-2 KO mice developed insulin resistance with reduced glucose transporter 2 and pancreatic and duodenal homeobox 1 levels, despite increased β-cell mass and hyperplasia. Thus, although β-cell mass was increased, HFD-fed male TIMP-2 KO mice develop diabetes likely due to β-cell exhaustion and failure. TIMP-2 mRNA, whose expression was greatest in sc adipose tissue, was down-regulated in HFD-fed wild-type males, but not females. Furthermore, HFD increased membrane type 1-MMP (MMP-14) expression and activity in male, but not female, sc adipose tissue. Strikingly, MMP-14 expression increased to a greater extent in TIMP-2 KO males and was associated with decreased adipocyte collagen. Taken together, these findings demonstrate a role for TIMP-2 in maintaining extracellular matrix integrity necessary for normal β-cell and adipocyte physiology and that loss of extracellular matrix integrity may underlie diabetic and obesogenic phenotypes.

Fragmented forms of insulin-like growth factor binding protein-1 in amniotic fluid of patients with preterm labor and intact membranes

To determine the clinical significance of an increase in various fragmented forms of insulin-like growth factor binding protein-1 (IGFBP-1) in amniotic fluid (AF), a retrospective cohort study was conducted in 103 consecutive patients with preterm labor and intact membranes. Amniotic fluid samples were cultured for aerobic and anaerobic bacteria, and mycoplasmas, and then assayed for matrix metalloproteinase-8. Fragmented-to-intact IGFBP-1 ratios were evaluated by densitometric analysis of Western blot assays. Intact IGFBP-1 (30 kDa) and 21, 17, and 12 kDa fragments were detected in AF. Median ratios of fragmented-to-intact IGFBP-1 were higher in patients whose neonates had significant morbidity than in those whose neonates did not (P < .05), in patients spontaneously delivered within 2 and 7 days from amniocentesis than in those delivered after 2 and 7 days (P < .05), and in patients with intra-amniotic infection/inflammation than in those without (P < .001). Collectively, fragmented IGFBP-1 in AF may be indicators for adverse perinatal outcomes.

Acute regulation of IGF-I by alterations in post-exercise macronutrients

This investigation sought to examine the contributions of exercise and nutrient replenishment on in vivo regulation of the insulin-like growth factor-I (IGF-I) axis components. Eight college-aged males completed three high-intensity interval training (HIIT) protocols followed by three post-exercise nutritional protocols: (1) placebo (EX); (2) carbohydrate only (CHO); and (3) essential amino acid/carbohydrate (EAA/CHO). Samples were analyzed for growth hormone (GH), free IGF-I, IGFBP-1, IGFBP-2, insulin, hematocrit, hemoglobin, serum leucine, matrix metalloproteinase-9 (MMP-9) proteolytic activity, and presence of IGFBP-3 protease activity. No evidence for IGFBP-3 proteolysis was observed. Significant increases in [free IGF-I] and [leucine] were observed in the EAA/CHO group only. Significant differences were noted in [IGFBP-1] and [IGFBP-2] across conditions. Significant increases in [GH] and MMP-9 activity were observed in all groups. These results indicate that post-exercise macronutrient ratio is a determinant of [free IGF-I], [IGFBP-1 and -2] and may play a role in modulating the IGF-I axis in vivo.

A bioresponsive hydrogel tuned to chondrogenesis of human mesenchymal stem cells

Cartilage tissue engineering aims to replace damaged or diseased tissue with a functional regenerate that restores joint function. Scaffolds are used to deliver cells and facilitate tissue development, but they can also interfere with the structural assembly of the cartilage matrix. Biodegradable scaffolds have been proposed as a means to improve matrix deposition and the biomechanical properties of neocartilage. The challenge is designing scaffolds with appropriate degradation rates, ideally such that scaffold degradation is proportional to matrix deposition. In this study, we developed a bioresponsive hydrogel with cell-mediated degradation aligned to the chondrogenic differentiation of human mesenchymal stem cells (hMSCs). We identified matrix metalloproteinase 7 (MMP7) as an enzyme with a temporal expression pattern that corresponded with cartilage development. By embedding MMP7 peptide substrates within a poly(ethylene glycol) diacrylate backbone, we built MMP7-sensitive hydrogels with distinct degradation rates. When MMP7-sensitive scaffolds were compared with nondegradable scaffolds in vitro, photoencapsulated hMSCs produced neocartilage constructs with more extensive collagenous matrices, as demonstrated through immunohistochemistry and biochemical quantification of matrix molecules. Furthermore, these changes translated into an increased dynamic compressive modulus. This work presents a practical strategy for designing biomaterials uniquely tuned to individual biological processes.