IGF-I enhances α5β1 integrin expression and cell motility in human chondrosarcoma cells

The Role of IGF/IGF-IR-Signaling and Extracellular Matrix Effectors in Bone Sarcoma Pathogenesis

Simple Summary

Bone sarcomas are mesenchymal origin tumors. Bone sarcoma patients show a variable response or do not respond to chemotherapy. Notably, improving efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Most clinical trials aiming at the IGF pathway have had limited success. Developing combinatorial strategies to enhance antitumor responses and better classify the patients that could best benefit from IGF-axis targeting therapies is in order. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects bone sarcomas’ basal functions and their response to therapy. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

Abstract

Bone sarcomas, mesenchymal origin tumors, represent a substantial group of varying neoplasms of a distinct entity. Bone sarcoma patients show a limited response or do not respond to chemotherapy. Notably, developing efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Whereas failures have been registered in creating novel targeted therapeutics aiming at the IGF pathway, new agent development should continue, evaluating combinatorial strategies for enhancing antitumor responses and better classifying the patients that could best benefit from these therapies. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects sarcomas’ basal functions and their response to therapy. This review highlights key studies focusing on IGF signaling in bone sarcomas, specifically studies underscoring novel properties that make this system an attractive therapeutic target and identifies new relationships that may be exploited. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

Antimetastatic Potential of Rhodomyrtone on Human Chondrosarcoma SW1353 Cells

Chondrosarcoma is primary bone cancer, with the forceful capacity to cause local invasion and distant metastasis, and has a poor prognosis. Cancer metastasis is a complication of most cancers; it is one of the leading causes of cancer-related death. Rhodomyrtone is a pure compound that has been shown to induce apoptosis and antimetastasis in skin cancer. However, the inhibitory effect of rhodomyrtone on human chondrosarcoma cell metastasis is largely unknown. Effect of rhodomyrtone on cell viability in SW1353 cell was determined by MTT assay. Antimigration, anti-invasion, and antiadhesion were carried out to investigate the antimetastatic potential of rhodomyrtone on SW1353 cells. Gelatin zymography was performed to determine matrix metalloproteinase-2 (MMP-2) and MMP-9 activities. The effect of rhodomyrtone on the underlying mechanisms was performed by Western blot analysis. The results demonstrated that rhodomyrtone reduced cell viability of SW1353 cells at the low concentration (<3 μg/mL); cell viability was >80%. Rhodomyrtone at the subcytotoxic concentrations (0.5, 1.5, and 3 μg/mL) significantly inhibited cell migration, invasion, and adhesion of SW1353 cells in a dose-dependent fashion. Protein expression of integrin αv, integrin β3, and the downstream migratory proteins including focal adhesion kinase (FAK) and the phosphorylation of serine/threonine AKT, Ras, RhoA, Rac1, and Cdc42 were inhibited after treatment with rhodomyrtone. Moreover, we found that rhodomyrtone decreased the protein level of MMP-2 and MMP-9 as well as the enzyme activity in SW1353 cells. Meanwhile, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 expression was increased in a dose-dependent fashion. Besides, rhodomyrtone dramatically inhibited the expression of growth factor receptor-bound protein-2 (GRB2) and the phosphorylated form of extracellular signal regulation kinase1/2 (ERK1/2) and c-Jun N-terminal kinase1/2 (JNK1/2). These results indicated that rhodomyrtone inhibited SW1353 cell migration, invasion, and metastasis by suppressing integrin αvβ3/FAK/AKT/small Rho GTPases pathway as well as downregulation of MMP-2/9 via ERK and JNK signal inhibition. These findings indicate that rhodomyrtone possessed the antimetastasis activity that may be used for antimetastasis therapy in the future.

Platelet-rich plasma inhibits osteoblast apoptosis and actin cytoskeleton disruption induced by gingipains through upregulating integrin β1

The aim of this study was to explore the effects of platelet-rich plasma on gingipain-caused changes in cell morphology and apoptosis of osteoblasts. Mouse osteoblasts MC3T3-E1 cells were treated with gingipain extracts from Porphyromonas gingivalis in the presence or absence of platelet-rich plasma. Apoptosis was detected with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. F-actin was determined by phalloidin-fluorescent staining and observed under confocal microscopy. Western blot analysis was used to detect integrin β1, F-actin, and G-actin protein expressions. A knocking down approach was used to determine the role of integrin β1. The platelet-rich plasma protected osteoblasts from gingipain-induced apoptosis in a dose-dependent manner, accompanied by upregulation of integrin β1. Platelet-rich plasma reversed the loss of F-actin integrity and decrease of F-actin/G-actin ratio in osteoblasts in the presence of gingipains. By contrast, the effects of platelet-rich plasma were abrogated by knockdown of integrin β1. The platelet-rich plasma failed to reduce cell apoptosis and reorganize the cytoskeleton after knockdown of integrin β1. In conclusion, platelet-rich plasma inhibits gingipain-induced osteoblast apoptosis and actin cytoskeleton disruption by upregulating integrin β1 expression.

Exosomes in Bone Sarcomas: Key Players in Metastasis

Bone sarcomas are rare cancers which often present with metastatic disease and are still associated with poor survival rates. Studies in the last decade have identified that exosomes, a type of extracellular vesicle released by cells, play an important role in tumour progression and dissemination. Through the transfer of their cargo (RNAs, proteins, and lipids) across cells, they are involved in cellular cross-talk and can induce changes in cellular behaviour. Exosomes have been shown to be important in metastasis organotropism, induction of angiogenesis and vascular permeability, the education of cells towards a pro-metastatic phenotype or the interaction between stromal and tumour cells. Due to the importance exosomes have in disease progression and the high incidence of metastasis in bone sarcomas, recent studies have evaluated the implications of these extracellular vesicles in bone sarcomas. In this review, we discuss the studies that evaluate the role of exosomes in osteosarcoma, Ewing sarcoma, and preliminary data on chondrosarcoma.

Chondrosarcoma: biology, genetics, and epigenetics

Chondrosarcomas constitute a heterogeneous group of primary bone cancers characterized by hyaline cartilaginous neoplastic tissue. They are the second most common primary bone malignancy. The vast majority of chondrosarcomas are conventional chondrosarcomas, and most conventional chondrosarcomas are low- to intermediate-grade tumors (grade 1 or 2) which have indolent clinical behavior and low metastatic potential. Recurrence augurs a poor prognosis, as conventional chondrosarcomas are both radiation and chemotherapy resistant. Recent discoveries in the biology, genetics, and epigenetics of conventional chondrosarcomas have significantly advanced our understanding of the pathobiology of these tumors and offer insight into potential therapeutic targets.

Molecular oncogenesis of chondrosarcoma: impact for targeted treatment

PURPOSE OF REVIEW

The prognosis of patients with unresectable or metastatic chondrosarcoma of the bone is poor. Chondrosarcomas are in general resistant to chemotherapy and radiotherapy. This review discusses recent developments in the characterization of molecular pathways involved in the oncogenesis of chondrosarcoma that should be explored to improve prognosis of patients with advanced chondrosarcoma.

RECENT FINDINGS

The different oncogenic pathways for chondrosarcoma have become better defined. These include alterations in pathways such as isocitrate dehydrogenase mutation, hedgehog signalling, the retinoblastoma protein and p53 pathways, apoptosis and survival mechanisms, and several tyrosine kinases. These specific alterations can be employed for use in clinical interventions in advanced chondrosarcoma.

SUMMARY

As many different genetic alterations in chondrosarcoma have been identified, it is of the utmost importance to classify druggable targets that may improve the prognosis of chondrosarcoma patients. In recent years an increased number of trials evaluating targeted therapies are being conducted. As chondrosarcoma is an orphan disease consequently all studies are performed with small numbers of patients. The results of clinical studies so far have been largely disappointing. Therapeutic intervention studies of these new targets emerging from preclinical studies are of highest importance to improve prognosis of chondrosarcoma patients with advanced disease.

Correlations of IGF-1R and COX-2 Expressions with Ras and BRAF Genetic Mutations, Clinicopathological Features and Prognosis of Colorectal Cancer Patients

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.

No preclinical rationale for IGF1R directed therapy in chondrosarcoma of bone

Background

Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of the role of the IGF pathway in chondrosarcoma to determine if it can be a target for therapy, which was therefore explored in this study.

Methods

Expression of mediators of IGF1R signalling and phosphorylation status of IRS1 was determined in chondrosarcoma cell lines by qRT-PCR and western blot. The effect of activation and inhibition of IGF1R signalling on downstream targets was assessed by western blot. Ten chondrosarcoma cell lines were treated with OSI-906 (IGF1R and IR dual inhibitor) after which cell proliferation and migration were determined by a viability assay and the xCELLigence system, respectively. In addition, four chondrosarcoma cell lines were treated with a combination of doxorubicin and OSI-906. By immunohistochemistry, IGF1R expression levels were determined in tissue microarrays of 187 cartilage tumours and ten paraffin embedded cell lines.

Results

Mediators of IGF1R signalling are heterogeneously expressed and phosphorylated IRS1 was detected in 67 % of the tested chondrosarcoma cell lines, suggesting that IGF1R signalling is active in a subset of chondrosarcoma cell lines. In the cell lines with phosphorylated IRS1, inhibition of IGF1R signalling decreased phosphorylated Akt levels and increased IGF1R expression, but it did not influence MAPK or S6 activity. In line with these findings, treatment with IGF1R/IR inhibitors did not impact proliferation or migration in any of the chondrosarcoma cell lines, even upon stimulation with IGF1. Although synergistic effects of IGF1R/IR inhibition with doxorubicin are described for other cancers, our results demonstrate that this was not the case for chondrosarcoma. In addition, we found minimal IGF1R expression in primary tumours in contrast to the high expression detected in chondrosarcoma cell lines, even if both were derived from the same tumour, suggesting that in vitro culturing upregulates IGF1R expression.

Conclusions

The results from this study indicate that the IGF pathway is not essential for chondrosarcoma growth, migration or chemoresistance. Furthermore, IGF1R is only minimally expressed in chondrosarcoma primary tumours. Therefore, the IGF pathway is not expected to be an effective therapeutic target for chondrosarcoma of bone.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2522-8) contains supplementary material, which is available to authorized users.

Insulin-like growth factor binding protein-3 inhibits cell adhesion via suppression of integrin β4 expression

We previously reported that IGF binding protein-3 (IGFBP-3), a major IGF-binding protein in human serum, regulates angiogenic activities of human head and neck squamous cell carcinoma (HNSCC) cells and human umbilical vein endothelial cells (HUVECs) through IGF-dependent and IGF-independent mechanisms. However, the role of IGFBP-3 in cell adhesion is largely unknown. We demonstrate here that IGFBP-3 inhibits the adhesion of HNSCC cells and HUVECs to the extracellular matrix (ECM). IGFBP-3 reduced transcription of a variety of integrins, especially integrin β₄, and suppressed phosphorylation of focal adhesion kinase (FAK) and Src in these cells through both IGF-dependent and IGF-independent pathways. IGFBP-3 was found to suppress the transcription of c-fos and c-jun and the activity of AP1 transcription factor. The regulatory effect of IGFBP-3 on integrin β₄ transcription was attenuated by blocking c-jun and c-fos gene expression via siRNA transfection. Taken together, our data show that IGFBP-3 has IGF-dependent and -independent inhibitory effects on intracellular adhesion signaling in HNSCC and HUVECs through its ability to block c-jun and c-fos transcription and thus AP-1-mediated integrin β₄ transcription. Collectively, our data suggest that IGFPB-3 may be an effective cancer therapeutic agent by blocking integrin-mediated adhesive activity of tumor and vascular endothelial cells.

The integrin adhesome: from genes and proteins to human disease

The adhesive interactions of cells with their environment through the integrin family of transmembrane receptors have key roles in regulating multiple aspects of cellular physiology, including cell proliferation, viability, differentiation and migration. Consequently, failure to establish functional cell adhesions, and thus the assembly of associated cytoplasmic scaffolding and signalling networks, can have severe pathological effects. The roles of specific constituents of integrin-mediated adhesions, which are collectively known as the 'integrin adhesome', in diverse pathological states are becoming clear. Indeed, the prominence of mutations in specific adhesome molecules in various human diseases is now appreciated, and experimental as well as in silico approaches provide insights into the molecular mechanisms underlying these pathological conditions.

Novel strategies for the treatment of chondrosarcomas: targeting integrins

Chondrosarcomas are a heterogeneous group of malignant bone tumors that are characterized by the production of cartilaginous extracellular matrix. They are the second most frequently occurring type of bone malignancy. Surgical resection remains the primary mode of treatment for chondrosarcomas, since conventional chemotherapy and radiotherapy are largely ineffective. Treatment of patients with high-grade chondrosarcomas is particularly challenging, owing to the lack of effective adjuvant therapies. Integrins are cell surface adhesion molecules that regulate a variety of cellular functions. They have been implicated in the initiation, progression, and metastasis of solid tumors. Deregulation of integrin expression and/or signaling has been identified in many chondrosarcomas. Therefore, the development of new drugs that can selectively target regulators of integrin gene expression and ligand-integrin signaling might hold great promise for the treatment of these cancers. In this review, we provide an overview of the current understanding of how growth factors, chemokines/cytokines, and other inflammation-related molecules can control the expression of specific integrins to promote cell migration. We also review the roles of specific subtypes of integrins and their signaling mechanisms, and discuss how these might be involved in tumor growth and metastasis. Finally, novel therapeutic strategies for targeting these molecules will be discussed.

IGF-IR promotes prostate cancer growth by stabilizing α5β1 integrin protein levels

Dynamic crosstalk between growth factor receptors, cell adhesion molecules and extracellular matrix is essential for cancer cell migration and invasion. Integrins are transmembrane receptors that bind extracellular matrix proteins and enable cell adhesion and cytoskeletal organization. They also mediate signal transduction to regulate cell proliferation and survival. The type 1 insulin-like growth factor receptor (IGF-IR) mediates tumor cell growth, adhesion and inhibition of apoptosis in several types of cancer. We have previously demonstrated that β1 integrins regulate anchorage-independent growth of prostate cancer (PrCa) cells by regulating IGF-IR expression and androgen receptor-mediated transcriptional functions. Furthermore, we have recently reported that IGF-IR regulates the expression of β1 integrins in PrCa cells. We have dissected the mechanism through which IGF-IR regulates β1 integrin expression in PrCa. Here we report that IGF-IR is crucial for PrCa cell growth and that β1 integrins contribute to the regulation of proliferation by IGF-IR. We demonstrate that β1 integrin regulation by IGF-IR does not occur at the mRNA level. Exogenous expression of a CD4 - β1 integrin cytoplasmic domain chimera does not interfere with such regulation and fails to stabilize β1 integrin expression in the absence of IGF-IR. This appears to be due to the lack of interaction between the β1 cytoplasmic domain and IGF-IR. We demonstrate that IGF-IR stabilizes the β1 subunit by protecting it from proteasomal degradation. The α5 subunit, one of the binding partners of β1, is also downregulated along with β1 upon IGF-IR knockdown while no change is observed in the expression of the α2, α3, α4, α6 and α7 subunits. Our results reveal a crucial mechanistic role for the α5β1 integrin, downstream of IGF-IR, in regulating cancer growth.

Src kinases in chondrosarcoma chemoresistance and migration: dasatinib sensitises to doxorubicin in TP53 mutant cells

BACKGROUND

Chondrosarcomas are malignant cartilage-forming tumours of bone. Because of their resistance to conventional chemotherapy and radiotherapy, currently no treatment strategies exist for unresectable and metastatic chondrosarcoma. Previously, PI3K/AKT/GSK3β and Src kinase pathways were shown to be activated in chondrosarcoma cell lines. Our aim was to investigate the role of these kinases in chemoresistance and migration in chondrosarcoma in relation to TP53 mutation status.

METHODS

We used five conventional and three dedifferentiated chondrosarcoma cell lines and investigated the effect of PI3K/AKT/GSK3β pathway inhibition (enzastaurin) and Src pathway inhibition (dasatinib) in chemoresistance using WST assay and live cell imaging with AnnexinV staining. Immunohistochemistry on tissue microarrays (TMAs) containing 157 cartilaginous tumours was performed for Src family members. Migration assays were performed with the RTCA xCelligence System.

RESULTS

Src inhibition was found to overcome chemoresistance, to induce apoptosis and to inhibit migration. Cell lines with TP53 mutations responded better to combination therapy than wild-type cell lines (P=0.002). Tissue microarray immunohistochemistry confirmed active Src (pSrc) signalling, with Fyn being most abundantly expressed (76.1%).

CONCLUSION

These results strongly indicate Src family kinases, in particular Fyn, as a potential target for the treatment of inoperable and metastatic chondrosarcomas, and to sensitise for doxorubicin especially in the presence of TP53 mutations.

Berberine Reduces the Metastasis of Chondrosarcoma by Modulating the α v β 3 Integrin and the PKC δ , c-Src, and AP-1 Signaling Pathways

Chondrosarcoma is a primary malignant bone cancer, with a potent capacity to invade locally and cause distant metastasis, especially to the lungs. Patients diagnosed with chondrosarcoma have poor prognosis. Berberine, an active component of the Ranunculaceae and Papaveraceae families of plant, has been proven to induce tumor apoptosis and to prevent the metastasis of cancer cells. However, the effects of berberine in human chondrosarcoma are largely unknown. In this study, we found that berberine did not induce cell apoptosis in human primary chondrocytes and chondrosarcoma cells. However, at noncytotoxic concentrations, berberine reduced the migration and invasion of chondrosarcoma cancer cells. Integrins are the major adhesive molecules in mammalian cells and have been associated with the metastasis of cancer cells. We also found that incubation of chondrosarcoma cells with berberine reduced mRNA transcription for, and cell surface expression of, the αvβ3 integrin, with additional inhibitory effects on PKCδ, c-Src, and NF-κB activation. Thus, berberine may be a novel antimetastasis agent for the treatment of metastatic chondrosarcoma.

The role of the insulin-like growth factor-I receptor in malignancy: an update

In the past three decades, evidence has been accumulating that the IGF-I receptor/ligand system plays an important role in malignant disease. This has led to a search for specific inhibitors of the IGF receptor for cancer therapy, revealing some predictable, but also unexpected challenges. Here we review recent data that highlight the essential role of the IGF axis in several important steps in cancer cell progression and metastasis and highlight cellular processes that have been the focus of much interest and new insight in recent years. Strategies used to target the IGF axis clinically are summarized and the obstacles encountered are discussed.