Function Of S100A4 Research Articles

Biological and angiogenic functions of S100A4 in ovarian cancer

Objectives: S100A4, a S100-calcium-binding family protein is a candidate marker of tumor metastasis. Biological functions of S100A4 in ovarian cancer are not well defined. This study was conducted to delineate the biological function of S100A4 in ovarian cancer and to determine how S100A4 promotes angiogenesis. We have investigated the mechanistic properties of S100A4's nuclear translocation and identified means to block it for effective treatment of ovarian cancer. We also investigated whether inhibition of S100A4 can restore sensitivity to cisplatin in chemoresistant cell-lines.

OP0176 S100a4 Regulates the Src-Thyrosine Kinase Dependent Differentiation of TH17 Cells in Rheumatoid Arthritis

BackgroundA calcium-binding protein S100A4 regulates non-muscle myosin assembly and activity and plays important part in cell motility and differentiation. The binding of S100A4 to calcium drives conformation changes and permits...

A link between inflammation and metastasis: serum amyloid A1 and A3 induce metastasis, and are targets of metastasis-inducing S100A4

S100A4 is implicated in metastasis and chronic inflammation, but its function remains uncertain. Here we establish an S100A4-dependent link between inflammation and metastatic tumor progression. We found that the acute-phase response proteins serum amyloid A (SAA) 1 and SAA3 are transcriptional targets of S100A4 via Toll-like receptor 4 (TLR4)/nuclear factor-κB signaling. SAA proteins stimulated the transcription of RANTES (regulated upon activation normal T-cell expressed and presumably secreted), G-CSF (granulocyte-colony-stimulating factor) and MMP2 (matrix metalloproteinase 2), MMP3, MMP9 and MMP13. We have also shown for the first time that SAA stimulate their own transcription as well as that of proinflammatory S100A8 and S100A9 proteins. Moreover, they strongly enhanced tumor cell adhesion to fibronectin, and stimulated migration and invasion of human and mouse tumor cells. Intravenously injected S100A4 protein induced expression of SAA proteins and cytokines in an organ-specific manner. In a breast cancer animal model, ectopic expression of SAA1 or SAA3 in tumor cells potently promoted widespread metastasis formation accompanied by a massive infiltration of immune cells. Furthermore, coordinate expression of S100A4 and SAA in tumor samples from colorectal carcinoma patients significantly correlated with reduced overall survival. These data show that SAA proteins are effectors for the metastasis-promoting functions of S100A4, and serve as a link between inflammation and tumor progression.

Abstract 833: S100A4 interacts with p53 in the nucleus promoting its degradation.

Abstract Background. S100A4 is a calcium binding protein which has no known enzymatic activity, but it exerts its function by binding and regulating other molecules, among which have been described Myosin and p53. S100A4 has been shown to be upregulated in several types of cancers, correlating with poor prognosis and metastasis. In a previous study (Orre et al., 2007), S100A4 has been shown to be involved the cellular response to ionizing irradiation in a p53 dependent manner; our aim here was therefore to investigate the cellular interaction partners of S100A4 in response to p53 and then, based on this data, to further elucidate the cellular function of S100A4. Observations. Nutlin-3A is a compound that specifically stabilizes p53 through inhibiting the interaction between p53 and mdm2. We could show an interaction between S100A4 and p53 via immunoprecipitation in the NSCLC cell line A549 (which has a high expression of S100A4 and a wild-type p53), and that this interaction is increased after Nutlin-3A treatment. The interaction has been independently confirmed via Proximity Ligation Assay, showing as well that the protein complexes are localized in the nucleus. Since this interaction increased after inhibition of the mdm2-p53 interaction, we hypothesized that S100A4 could be involved in regulation of p53 degradation; therefore we generated two cell lines from A549, infected with S100A4 shRNA (shS100A4) or an Empty Vector shRNA (shEV) as a control. Knockdown of S100A4 resulted in stabilization of p53 and transactivation of p53 transcriptional targets; it also resulted in higher sensitivity to cisplatin-mediated apoptotic cell death, measured as a drop in mitochondrial membrane potential, caspase-3 activation and AV/PI assay. We confirmed this finding by an independent method using transient S100A4 down regulation via siRNA; this resulted in an increase in p53 level and of p21 and MDM2 level in A549 adenocarcinoma cells. S100A4 siRNA resulted also in p53-dependent growth arrest, that was reversed after co-transfecting p53 siRNA. Conclusions. Our data show that S100A4 interacts with p53 increasing its degradation, resulting in higher cell viability and lower apoptosis after cisplatin treatment. A possible correlation in patients between S100A4 overexpression and cisplatin resistance could be used to drive treatment selection. Citation Format: Lukas Orre, Elena Panizza, Vitaliy Kaminskyy, Torbjörn Gräslund, Boris Zhivotovsky, Janne Lehtiö. S100A4 interacts with p53 in the nucleus promoting its degradation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 833. doi:10.1158/1538-7445.AM2013-833

Peptide Mimetic of the S100A4 Protein Modulates Peripheral Nerve Regeneration and Attenuates the Progression of Neuropathy in Myelin Protein P0 Null Mice

We recently found that S100A4, a member of the multifunctional S100 protein family, protects neurons in the injured brain and identified two sequence motifs in S100A4 mediating its neurotrophic effect. Synthetic peptides encompassing these motifs stimulated neuritogenesis and survival in vitro and mimicked the S100A4-induced neuroprotection in brain trauma. Here, we investigated a possible function of S100A4 and its mimetics in the pathologies of the peripheral nervous system (PNS). We found that S100A4 was expressed in the injured PNS and that its peptide mimetic (H3) affected the regeneration and survival of myelinated axons. H3 accelerated electrophysiological, behavioral and morphological recovery after sciatic nerve crush while transiently delaying regeneration after sciatic nerve transection and repair. On the basis of the finding that both S100A4 and H3 increased neurite branching in vitro, these effects were attributed to the modulatory effect of H3 on initial axonal sprouting. In contrast to the modest effect of H3 on the time course of regeneration, H3 had a long-term neuroprotective effect in the myelin protein P0 null mice, a model of dysmyelinating neuropathy (Charcot-Marie-Tooth type 1 disease), where the peptide attenuated the deterioration of nerve conduction, demyelination and axonal loss. From these results, S100A4 mimetics emerge as a possible means to enhance axonal sprouting and survival, especially in the context of demyelinating neuropathies with secondary axonal loss, such as Charcot-Marie-Tooth type 1 disease. Moreover, our data suggest that S100A4 is a neuroprotectant in PNS and that other S100 proteins, sharing high homology in the H3 motif, may have important functions in PNS pathologies.

Cysteine 81 Is Critical for the Interaction of S100A4 and Myosin-IIA

Overexpression of S100A4, a member of the S100 family of Ca(2+)-binding proteins, is associated with a number of human pathologies, including fibrosis, inflammatory disorders, and metastatic disease. The identification of small molecules that disrupt S100A4/target interactions provides a mechanism for inhibiting S100A4-mediated cellular activities and their associated pathologies. Using an anisotropy assay that monitors the Ca(2+)-dependent binding of myosin-IIA to S100A4, NSC 95397 was identified as an inhibitor that disrupts the S100A4/myosin-IIA interaction and inhibits S100A4-mediated depolymerization of myosin-IIA filaments. Mass spectrometry demonstrated that NSC 95397 forms covalent adducts with Cys81 and Cys86, which are located in the canonical target binding cleft. Mutagenesis studies showed that covalent modification of just Cys81 is sufficient to inhibit S100A4 function with respect to myosin-IIA binding and depolymerization. Remarkably, substitution of Cys81 with serine or alanine significantly impaired the ability of S100A4 to promote myosin-IIA filament disassembly. As reversible covalent cysteine modifications have been observed for several S100 proteins, we propose that modification of Cys81 may provide an additional regulatory mechanism for mediating the binding of S100A4 to myosin-IIA.

S100A4 protects gastric cancer cells from anoikis through regulation of αv and α5 integrin

Detachment from the extracellular matrix induces a form of programmed cell death termed anoikis. Resistance to anoikis permits cancer cells to survive in systemic circulation and facilitates their metastasis to distant organs. It is well known that S100A4 is overexpressed in many tumors and involved in tumor metastasis, but the mechanisms of the metastasis-promoting function of S100A4 are not fully understood. We hypothesized that S100A4 might play a role in anoikis of gastric cancer cells and further affects their metastasis. To test this hypothesis, we changed the expression of S100A4 by means of RNA interference or experimental overexpression and investigated the effect on anoikis. We found that knockdown of S100A4 by RNA interference led to significantly increased anoikis, whereas overexpression of S100A4 resulted in inhibition of anoikis. Furthermore, we provide evidence that inhibition of S100A4 resulted in the downregulation of α5 and αv integrin expression. These findings suggest that S100A4 protects gastric cancer cells from anoikis by regulation of αv and α5 integrin expression, which sheds a novel light for the role of S100A4 in cancer metastasis.

Stable knockdown of S100A4 suppresses cell migration and metastasis of osteosarcoma

S100A4, a 10-12 kDa calcium-binding protein, plays functional roles in tumor progression and metastasis. The present study aimed to investigate the function of S100A4 in osteosarcoma (OS) metastasis, using a loss-of-function approach. Our previous expression profiling analysis revealed that S100a4 was preferentially expressed in the highly metastatic mouse OS cell line, LM8. Introducing a short hairpin ribonucleic acid (shRNA) targeting S100a4 using a newly established vector containing insulators and transposons, we established stable LM8 subclones with almost 100% silencing of endogenous S100a4 protein. These transfectants showed a significant suppression of cell migration in vitro as well as a marked reduction in their ability to colonize the lung and form pulmonary metastases in vivo following intravenous inoculation, whereas there was no significant change in cell proliferation or cell attachment to fibronectin, laminin, and type I collagen. Expression and phosphorylation of ezrin, an emerging OS metastasis-associated factor, and expression of MMPs, remained the same in S100a4-shRNA clones. In 61 human OS, immunohistochemical analysis showed that lesional cells in 85.2% samples expressed S100A4 protein, and the immunoreactivity was primarily cytoplasmic, but it also showed occasional nuclear localization. Chondroblastic and osteoblastic OS subtypes expressed more S100A4 than fibroblastic subtypes. The causative role of S100A4 in OS lung metastasis shown in the murine xenograft model, together with the high proportion of primary human OS expressing S100A4, suggest that S100A4 protein represents an important potential target for future OS therapy.

Metastasis-inducing S100A4 and RANTES cooperate in promoting tumor progression in mice.

BackgroundThe tumor microenvironment has been described as a critical milieu determining tumor growth and metastases. A pivotal role of metastasis-inducing S100A4 in the development of tumor stroma has been proven in animal models and verified in human breast cancer biopsies. Expression and release of S100A4 has been shown in various types of stroma composing cells, including fibroblasts and immune cells. However, the events implicated in upstream and downstream pathways regulating the activity of the extracellular S100A4 protein in the tumor milieu remain unsolved.Methodology/Principal FindingsWe studied the interplay between the tumor cell-derived cytokine regulated-upon-activation, normal T-cell expressed and secreted (RANTES; CCL5) and S100A4 which were shown to be critical factors in tumor progression. We found that RANTES stimulates the externalization of S100A4 via microparticle shedding from the plasma membrane of tumor and stroma cells. Conversely, the released S100A4 protein induces the upregulation of fibronectin (FN) in fibroblasts and a number of cytokines, including RANTES in tumor cells as well as stimulates cell motility in a wound healing assay. Importantly, using wild type and S100A4-deficient mouse models, we demonstrated a substantial influence of tumor cell-derived RANTES on S100A4 release into blood circulation which ultimately increases the metastatic burden in mice.Conclusions/SignificanceAltogether, the data presented strongly validate the pro-metastatic function of S100A4 in the tumor microenvironment and define how the tumor cell-derived cytokine RANTES acts as a critical regulator of S100A4-dependent tumor cell dissemination. Additionally, for the first time we demonstrated the mechanism of S100A4 release associated with plasma membrane microparticle shedding from various cells types.

Phenothiazines inhibit S100A4 function by inducing protein oligomerization

S100A4, a member of the S100 family of Ca(2+)-binding proteins, regulates carcinoma cell motility via interactions with myosin-IIA. Numerous studies indicate that S100A4 is not simply a marker for metastatic disease, but rather has a direct role in metastatic progression. These observations suggest that S100A4 is an excellent target for therapeutic intervention. Using a unique biosensor-based assay, trifluoperazine (TFP) was identified as an inhibitor that disrupts the S100A4/myosin-IIA interaction. To examine the interaction of S100A4 with TFP, we determined the 2.3 A crystal structure of human Ca(2+)-S100A4 bound to TFP. Two TFP molecules bind within the hydrophobic target binding pocket of Ca(2+)-S100A4 with no significant conformational changes observed in the protein upon complex formation. NMR chemical shift perturbations are consistent with the crystal structure and demonstrate that TFP binds to the target binding cleft of S100A4 in solution. Remarkably, TFP binding results in the assembly of five Ca(2+)-S100A4/TFP dimers into a tightly packed pentameric ring. Within each pentamer most of the contacts between S100A4 dimers occurs through the TFP moieties. The Ca(2+)-S100A4/prochlorperazine (PCP) complex exhibits a similar pentameric assembly. Equilibrium sedimentation and cross-linking studies demonstrate the cooperative formation of a similarly sized S100A4/TFP oligomer in solution. Assays examining the ability of TFP to block S100A4-mediated disassembly of myosin-IIA filaments demonstrate that significant inhibition of S100A4 function occurs only at TFP concentrations that promote S100A4 oligomerization. Together these studies support a unique mode of inhibition in which phenothiazines disrupt the S100A4/myosin-IIA interaction by sequestering S100A4 via small molecule-induced oligomerization.

Epidermal growth factor receptor ligands as new extracellular targets for the metastasis‐promoting S100A4 protein

The function of S100A4, a member of the calcium-binding S100 protein family, has been associated with tumor invasion and metastasis. Although an essential pro-metastatic role of extracellular S100A4 in tumor progression has been demonstrated, the identification of the precise underlying mechanisms and protein partners (receptors) has remained elusive. To identify putative targets for extracellular S100A4, we screened a phage display peptide library using S100A4 as bait. We identified three independent peptide motifs with varying affinities for the S100A4 protein. Sequence analyses indicated that the most abundant peptide mimicked the F/YCC motif present in the epidermal growth factor domain of ErbB receptor ligands. S100A4 selectively interacted with a number of epidermal growth factor receptor (EGFR) ligands, demonstrating highest affinity for amphiregulin. Importantly, we found that S100A4 stimulated EGFR/ErbB2 receptor signaling and enhanced the amphiregulin-mediated proliferation of mouse embryonic fibroblasts. S100A4-neutralizing antibodies, as well as EGFR- and ErbB2 receptor-specific tyrosine kinase inhibitors, blocked these effects. The present results suggest that extracellular S100A4 regulates tumor progression by interacting with EGFR ligands, thereby enhancing EGFR/ErbB2 receptor signaling and cell proliferation. Structured digital abstract: * MINT-7256556: EGF (uniprotkb:P01133) binds (MI:0407) to S100A4 (uniprotkb:P26447) by far western blotting (MI:0047) * MINT-7256512: BC (uniprotkb:P35070) binds (MI:0407) to S100A4 (uniprotkb:P26447) by far western blotting (MI:0047) * MINT-7256485, MINT-7256618, MINT-7256636: AR (uniprotkb:P15514) binds (MI:0407) to S100A4 (uniprotkb:P26447) by far western blotting (MI:0047) * MINT-7256494: HB-EGF (uniprotkb:Q99075) binds (MI:0407) to S100A4 (uniprotkb:P26447) by far western blotting (MI:0047) * MINT-7256502: P53 (uniprotkb:P04637) binds (MI:0407) to S100A4 (uniprotkb:P26447) by far western blotting (MI:0047) * MINT-7256654: S100A2 (uniprotkb:P29034) binds (MI:0407) to AR (uniprotkb:P15514) by far western blotting (MI:0047) * MINT-7256693: S100A5 (uniprotkb:P33763) binds (MI:0407) to AR (uniprotkb:P15514) by far western blotting (MI:0047) * MINT-7256593: S100A4 (uniprotkb:P26447) binds (MI:0407) to BC (uniprotkb:P35070) by pull down (MI:0096) * MINT-7256567: S100A4 (uniprotkb:P26447) binds (MI:0407) to AR (uniprotkb:P15514) by pull down (MI:0096).

Structure of Ca2+-Bound S100A4 and Its Interaction with Peptides Derived from Nonmuscle Myosin-IIA

S100A4, also known as mts1, is a member of the S100 family of Ca2+-binding proteins that is directly involved in tumor invasion and metastasis via interactions with specific protein targets, including nonmuscle myosin-IIA (MIIA). Human S100A4 binds two Ca2+ ions with the typical EF-hand exhibiting an affinity that is nearly 1 order of magnitude tighter than that of the pseudo-EF-hand. To examine how Ca2+ modifies the overall organization and structure of the protein, we determined the 1.7 A crystal structure of the human Ca2+-S100A4. Ca2+ binding induces a large reorientation of helix 3 in the typical EF-hand. This reorganization exposes a hydrophobic cleft that is comprised of residues from the hinge region,helix 3, and helix 4, which afford specific target recognition and binding. The Ca2+-dependent conformational change is required for S100A4 to bind peptide sequences derived from the C-terminal portion of the MIIA rod with submicromolar affinity. In addition, the level of binding of Ca2+ to both EF-hands increases by 1 order of magnitude in the presence of MIIA. NMR spectroscopy studies demonstrate that following titration with a MIIA peptide, the largest chemical shift perturbations and exchange broadening effects occur for residues in the hydrophobic pocket of Ca2+-S100A4. Most of these residues are not exposed in apo-S100A4 and explain the Ca2+ dependence of formation of theS100A4-MIIA complex. These studies provide the foundation for understanding S100A4 target recognition and may support the development of reagents that interfere with S100A4 function.

A Biosensor of S100A4 Metastasis Factor Activation: Inhibitor Screening and Cellular Activation Dynamics

S100A4, a member of the S100 family of Ca2+-binding proteins, displays elevated expression in malignant human tumors compared with benign tumors, and increased expression correlates strongly with poor patient survival. S100A4 has a direct role in metastatic progression, likely due to the modulation of actomyosin cytoskeletal dynamics, which results in increased cellular motility. We developed a fluorescent biosensor (Mero-S100A4) that reports on the Ca2+-bound, activated form of S100A4. Direct attachment of a novel solvatochromatic reporter dye to S100A4 results in a sensor that, upon activation, undergoes a 3-fold enhancement in fluorescence, thus providing a sensitive assay for use in vitro and in vivo. In cells, localized activation of S100A4 at the cell periphery is observed during random migration and following stimulation with lysophosphatidic acid, a known activator of cell motility and proliferation. Additionally, a screen against a library of FDA-approved drugs with the biosensor identified an array of phenothiazines as inhibitors of myosin-II associated S100A4 function. These data demonstrate the utility of the new biosensor both for drug discovery and for probing the cellular dynamics controlled by the S100A4 metastasis factor.

Metastasis-Associated Protein S100A4: Spotlight on its Role in Cell Migration

S100A4 (also known as Mts1, metastasin, p9Ka, pEL98, CAPL, calvasculin, Fsp-1, placental calcium-binding protein) belongs to the family of EF-hand calcium-binding proteins, whose expression is elevated in a number of pathological conditions. Although it is well documented that S100A4 is expressed in cancer cells and contributes to tumor cell motility and metastatic progression, the exact underlying mechanisms remain elusive. An important characteristic feature of S100 proteins is their dual function, inside and outside the cell. In this review, we focus on the intracellular function of S100A4. The review contains structural analysis of S1004 in comparison with other members of S100 proteins. Possible modes of the interaction of S100 proteins with targets are described. Several examples of best-studied molecular interactions involving S100A4 with heavy chain of nonmuscle myosin IIA, LAR-interacting protein liprin beta1 and tumor suppressor protein p53 are provided. We suggest that the binding of S100A4 to these molecules is critical for the S100A4 function. Further studies of the implications of these interactions in different molecular pathways may shed additional light on the role of S100A4 protein in the control of tumor cell motility and migration. We discuss the approaches for down-regulation of S100A4 expression and their potential for application in the clinics.

Intimal Smooth Muscle Cells of Porcine and Human Coronary Artery Express S100A4, a Marker of the Rhomboid Phenotype In Vitro

We reported that smooth muscle cell (SMC) populations isolated from normal porcine coronary artery media exhibit distinct phenotypes: spindle-shaped (S) and rhomboid (R). R-SMCs are recovered in higher proportion from stent-induced intimal thickening compared with media suggesting that they participate in intimal thickening formation. Our aim was to identify a marker of R-SMCs in vitro and to explore its possible expression in vivo. S- and R-SMC protein extracts were compared by means of 2-dimensional polyacrylamide gel electrophoresis followed by tandem mass spectrometry. S100A4 was found to be predominantly expressed in R-SMC extracts. Using a monoclonal S100A4 antibody we confirmed that S100A4 is highly expressed by R-SMCs and hardly detectable in S-SMCs. S100A4 was colocalized with alpha-smooth muscle actin in stress fibers of several quiescent cells and upregulated during migration. PDGF-BB, FGF-2 or coculture with endothelial cells, which modulate S-SMCs to a R-phenotype, increased S100A4 expression in both S- and R-SMCs. Silencing of S100A4 mRNA in R-SMCs decreased cell proliferation, suggesting a functional role for this protein. In vivo S100A4 was absent in normal porcine coronary artery media, but highly expressed by SMCs of stent-induced intimal thickening. In humans, S100A4 was barely detectable in coronary artery media and markedly expressed in SMCs of atheromatous and restenotic coronary artery lesions. Our results indicate that S100A4 is a marker of porcine R-SMCs in vitro and of intimal SMCs during intimal thickening development. It is also a marker of a large population of human atheromatous and restenotic SMCs. Clarifying S100A4 function might be useful to understand the evolution of atherosclerotic and restenotic processes.

Mutually antagonistic actions of S100A4 and S100A1 on normal and metastatic phenotypes

Increased levels of the homodimeric calcium-binding protein, S100A4, have been shown to cause a metastatic phenotype in at least three independent model systems of breast cancer and its presence in carcinoma cells has been shown to be associated with a reduction in the survival of patients suffering from a range of different cancers. S100A4 has been shown to interact in vitro with another member of the S100 family of proteins, S100A1. The purpose of the present study was to find out whether S100A1 could affect S100A4 function. Fluorescence resonance energy transfer was used to show the interaction of S100A4 and S100A1 in living cells and the binding affinities between S100A4 and S100A1 were determined using a biosensor. S100A1 reduced the S100A4 inhibition of nonmuscle myosin A self-association and phosphorylation in vitro. S100A1 reduced S100A4 induced motility and growth in soft agar and metastasis in vivo. The results show for the first time that interactions between different S100 proteins can affect cancer-related activity, and that the presence of S100A1 protein in carcinoma cells might modulate the effect of S100A4 on their metastatic abilities.

Functional significance of metastasis-inducing S100A4(Mts1) in tumor-stroma interplay.

Causal implication of S100A4 in inducing metastases was convincingly shown previously. However, the mechanisms that associate S100A4 with tumor progression are not well understood. S100A4 protein, as a typical member of the S100 family, exhibits dual, intracellular and extracellular, functions. This work is focused on the extracellular function of S100A4, in particular its involvement in tumor-stroma interplay in VMR (mouse adenocarcinoma cell line) tumor cells, which exhibit stroma-dependent metastatic phenotype. We demonstrated the reciprocal influence of tumor and stroma cells where tumor cells stimulate S100A4 secretion from fibroblasts in culture. In turn, extracellular S100A4 modifies the cytoskeleton and focal adhesions and triggers several other events in tumor cells. We found stabilization of the tumor suppressor protein p53 and modulation of its function. In particular, extracellular S100A4 down-regulates the pro-apoptotic bax and the angiogenesis inhibitor thrombospondin-1 genes. For the first time, we demonstrate here that the S100A4 protein added to the extracellular space strongly stimulates proteolytic activity of VMR cells. This activity most probably is associated with matrix metalloproteinases and, in particular, with matrix metalloproteinase-13. Finally, the application of the recombinant S100A4 protein confers stroma-independent metastatic phenotype on VMR tumor cells. In conclusion, our results indicate that metastasis-inducing S100A4 protein plays a pivotal role in the tumor-stroma environment. S100A4 released either by tumor or stroma cells triggers pro-metastatic cascades in tumor cells.