Role of osteopontin in osteosarcoma

Osteopontin, WNT3A, and ABCB5 Biomarkers Expression in Osteosarcoma Patients

Objective  This study aimed to correlate the expression, by immunohistochemistry, of the proteins OPN, ABCB5, and WNT3A from anatomopathological materials obtained from paraffin blocks, slides, or both, from patients with osteosarcoma (OS), analyzing epidemiological characteristics, as well as their presence and influence on the evolution and progression of the disease. Methods  After the initial case selection, we searched for the respective paraffin blocks and took only those with sufficient tumor mass to allow additional sections with no complete loss of biological material. The sarcoma area identification in representative paraffin blocks used multisample blocks (tissue microarray [TMA]) created on a BenchMark ULTRA (Roche Diagnostics Corporation, Indianapolis, IN, USA) instrument. Then, we analyzed the association between the expression of ABCB5, WNT3A, and osteopontin (OPN) markers with the variables age, location, and tissue type (Fisher exact test/Chi-squared test). Results  The average age of the patients was 23 years, and the rate of males and females was the same. We analyzed 40 slides from 28 OS patients seen from 2005 to 2017. Their follow-up time was 80.0 months, and the 5-year survival rate was 46.7%. Most metastases occurred in lung tissue (92.9%). Proteins ABCB5, OPN, and WNT3A did not present statistical significance when compared with age group, neo-adjuvant, adjuvant, or both, chemotherapy, location, survival, or death. Osteopontin was negative in all samples. WNT3A expression occurred in patients who died early. Conclusion  In an immunohistochemical study, ABCB5, OPN, and WNT3A did not have statistical significance. In the parameters analyzed, they did not seem to be a predictive or aggressive factor for OS.

High expression of integrin-binding sialoprotein (IBSP) is associated with poor prognosis of osteosarcoma

INTRODUCTION

Osteosarcoma is a malignant tumor, accounting for 20% of primary malignant bone tumors worldwide. However, the role of IBSP as a biomarker in osteosarcoma progression has not been studied yet.

METHODS

85 cases of IBSP expression and clinical characteristics were obtained from TARGET database. Through the Kaplan-Meier curve, subgroup analysis, and univariate and multivariate Cox analysis, we further assessed the independent predictive capacity of IBSP expression for overall survival (OS) and relapse-free survival (RFS).

RESULTS

The mRNA expression of IBSP was higher in osteosarcoma than normal tissue (P < 0.0001). IBSP expression grouped by vital status showed statistical differences (P = 0.042). The race (P = 0.0183), vital status (P = 0.0034), and sample type (P = 0.0020) showed significant differences. IBSP expression exhibited satisfied diagnostic ability for osteosarcoma. The univariate and multivariate analysis confirmed that IBSP expression was an independent risk factor for OS (HR = 3.425, 95% CI: 1.604-7.313, P = 0.002) and RFS (HR = 3.377, 95% CI: 1.775-6.424, P < 0.001) in osteosarcoma patients. High IBSP expression was significantly associated with poor OS and RFS (P < 0.0001). The higher IBSP expression was observed in osteosarcoma (P < 0.001), confirmed by the IHC staining. The CCK-8 and colony formation assay showed that IBSP knockdown inhibits cell proliferation while overexpression promotes cell proliferation (P < 0.05).

CONCLUSION

High expression of IBSP was associated with poor OS and RFS. IBSP could serve as a potential biomarker for osteosarcoma, which could aid in early detection and disease monitoring.

Evaluation of local and circulating osteopontin in malignant and benign primary bone tumors

Purpose

The development of novel and efficient biomarkers for primary bone cancers is of grave importance.

Methods

The expression pattern of osteopontin (OPN) was investigated in the 153 patients with benign (n = 72) and malignant (n = 81) primary bone cancers. Both local and circulating OPN mRNA expression levels and their protein concentration in serum and tumor site were assessed using real-time qRT-PCR, ELISA, and immunohistochemistry techniques, respectively. As a control, 29 healthy individuals were considered. The number of 153 tumor tissue specimens and the 153 paired margins were taken on surgical resection from the patients. 153 blood samples were also drained from all participants, then peripheral blood mononuclear cells (PBMC) and sera were separated.

Results

The mean mRNA expression was significantly higher in all of the cancerous tissues than the paired margins and the PBMC of the patients than the controls. Consistently, the protein concentrations of OPN in serum and tumor tissues were significantly higher in the patients. Furthermore, the malignant cases had significantly elevated the mRNA levels and the protein compared to the benign cases. OPN could potentially differentiate the patients from the controls with 100% sensitivity and specificity in serum. Moreover, OPN could predict some of the malignant cases' clinicopathological features, including metastasis, recurrence, grade, and response to chemotherapy.

Conclusions

In conclusion, OPN might be involved in the pathogenesis of primary bone tumors and can be considered as a potential biomarker to bone cancer diagnosis.

The cancer-related transcription factor RUNX2 modulates expression and secretion of the matricellular protein osteopontin in osteosarcoma cells to promote adhesion to endothelial pulmonary cells and lung metastasis

Osteosarcomas are bone tumors that frequently metastasize to the lung. Aberrant expression of the transcription factor, runt-related transcription factor 2 (RUNX2), is a key pathological feature in osteosarcoma and associated with loss of p53 and miR-34 expression. Elevated RUNX2 may transcriptionally activate genes mediating tumor progression and metastasis, including the RUNX2 target gene osteopontin (OPN/SPP1). This gene encodes a secreted matricellular protein produced by osteoblasts to regulate bone matrix remodeling and tissue calcification. Here we investigated whether and how the RUNX2/OPN axis regulates lung metastasis of osteosarcoma. Importantly, RUNX2 depletion attenuates lung metastasis of osteosarcoma cells in vivo. Using next-generation RNA-sequencing, protein-based assays, as well as the loss- and gain-of-function approaches in selected osteosarcoma cell lines, we show that osteopontin messenger RNA levels closely correlate with RUNX2 expression and that RUNX2 controls the levels of secreted osteopontin. Elevated osteopontin levels promote heterotypic cell-cell adhesion of osteosarcoma cells to human pulmonary microvascular endothelial cells, but not in the presence of neutralizing antibodies. Collectively, these findings indicate that the RUNX2/OPN axis regulates the ability of osteosarcoma cells to attach to pulmonary endothelial cells as a key step in metastasis of osteosarcoma cells to the lung.

Resveratrol in management of bone and spinal cancers

Bone cancer is a malignant primary tumour of the bone with different typing, such as, osteosarcoma, chondrosarcoma, Ewing's sarcoma and fibrosarcoma. Despite the clinical efficacy of conventional therapies of bone cancer, most patients eventually relapse and the disease remains incurable. Therefore, new therapeutic strategies are needed to improve patient outcome. In this review article, we have discussed the role of resveratrol in preventing bone and spinal cancers and therapeutics. Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural polyphenol, which has been widely reported as an anticancer molecule. Resveratrol exhibits multiple tumour-suppressing activities in bone cancer by affecting a series of critical events. It has the protective effects against oxidative injury, possesses antiproliferative activity and induces apoptosis in cancer cells. Resveratrol might be a good option for the treatment of different types of bone and spinal cancers.

Osteopontin: its potential role in cancer of children and young adults

Objective: Osteopontin (OPN) is aglyco-phosphoprotein, involved in tissue remodeling, inflammation and boneresorption. In various adult neoplasms OPN was shown to correlate with cancer progression, invasiveness and metastasis. Aim: to define the role of OPN in malignancies of children and young adults. Material and methods: a structured PubMed and Google Scholar literature analysis based on reports published in English between I'1995 and XII'2015. Results: 14 studies (four on hematological malignancies, four on bone tumors, three on CNS tumors, two on dendritic proliferative diseases and one on renal tumors) were identified. Higher levels of serum and cerebro-spinal fluid OPN protein, and high expressions of OPN mRNA and SPP1 gene were present in more aggressive and advanced childhood malignancies. In children with acute lymphoblastic leukemia with CNS involvement and with atypical teratoid/rhabdoid tumor (AT/RT) and medulloblastoma, the serum and CSF OPN levels reflected tumor bulk and response to therapy, while in children with AT/RT and multisystem Langerhans cell histiocytosis with high-risk organs involvement, high OPN serum levels correlated with poorer survival. To the contrary, in osteosarcoma, high OPN mRNA and SPP1 gene expressions correlated with better survival and good response to chemotherapy. Conclusions: The literature review suggests that OPN may play important roles in the development and progression of selected cancers of children and young adults, including acute lymphoblastic leukemia, malignant gliomas, AT/RT and Langerhans cell histiocytosis. However, limited number of published studies prevents from definite concluding on the clinical utility of OPN as a marker of diagnosis, prognosis and treatment monitoring in these pediatric cancers. Further studies performed in more numerous groups of patients with particular types of cancers of children and young adults are warranted.

Vitamin K4 inhibits the proliferation and induces apoptosis of U2OS osteosarcoma cells via mitochondrial dysfunction

Vitamin K (VK) is a group of fat‑soluble vitamins, which serve important roles in blood coagulation and bone metabolism. A recent study reported that several VK subtypes possess antitumor properties, however the antitumor effects of VK in osteosarcoma are unknown. The present study aimed to identify the antitumor effects of VK in osteosarcoma and the possible underlying mechanism of action. The effect of VK4 on cell viability was determined using a 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay. Cellular and nuclear morphological changes were observed by phase contrast microscopy. Cell cycle analysis, apoptotic rate, mitochondrial membrane potential and levels of reactive oxygen species (ROS) were detected by flow cytometry. In vitro cancer cell migration activities were evaluated using a Wound healing assay and Transwell microplates. The results demonstrated that VK4 arrested the cells in S phase and induced apoptosis. Additional mechanistic studies indicated that the induction of apoptosis by VK4 was associated with the increased production of reactive oxygen species, dissipation of the mitochondrial membrane potential, decreased Bcl‑2 family protein expression levels and activation of caspase‑3. In conclusion, the results suggest that the sensitivity of U2OS osteosarcoma cells to VK4 may be as a result of mitochondrial dysfunction. As it is readily available for human consumption, VK4 may therefore present a novel therapeutic candidate for the treatment of patients with osteosarcoma.

JNK pathway in osteosarcoma: pathogenesis and therapeutics

CONTEXT

The c-Jun NH2-terminal kinase (JNK) is a member of the mitogen-activated protein kinase super family. JNK can phosphorylate a number of activator protein-1 components, activating several transcription factors, and thus, JNK signaling pathway is being involved in several carcinogenic mechanisms.

OBJECTIVE

In this study, we have reviewed the recent updates of the association of JNK pathway with osteosarcoma (OS), which is one of the most common and aggressive bone malignancies.

METHODS

In this review, we have explored the databases like PubMed, Google Scholar, MEDLINE, etc., and collected the most relevant papers of JNK signaling pathway involved in the pathogenesis and therapeutics of OS.

RESULTS

Evidence showed that JNK is a master protein kinase that plays an important role in osteoblast proliferation, differentiation and apoptosis. Interesting reports showed that chemical JNK inhibitors reduce OS cell proliferation and metastasis. Many of the components of this pathway have now been identified and the application of JNK inhibitors has been proven to work in vivo in human and in animal models; however, JNK pathway has not been translated into clinical use.

CONCLUSION

Therapeutic interventions of potent and selective inhibitors of JNK might provide promising therapeutic approaches for the treatment of OS, and could improve the survival rate and quality of life of OS patients.

Osteopontin Involves Cisplatin Resistance and Poor Prognosis in Oral Squamous Cell Carcinoma

Background. Osteopontin (OPN) is a multifunctional cytokine involved in cell survival, migration, and adhesion. However, its role in chemosensitivity in locally advanced oral squamous cell carcinoma (OSCC) in humans has not yet been investigated. Methods. We enrolled 121 patients with locally advanced stage IVA/B OSCC receiving cisplatin-based IC followed by CCRT from January 1, 2006, through January 1, 2012. Immunohistochemistry was used to assess OPN expression in OSCC patients' biopsy specimens from paraffin blocks before treatment. In addition, MTT/colony formation assay was used to estimate the influence of OPN in an oral cancer cell line treated with cisplatin. Results. Of the 121 patients, 94 had positive OPN findings and 52 responded to IC followed by CCRT. Positive osteopontin immunostaining also correlated significantly with positive N status/TNM stage/male gender and smoking. Univariate analyses showed that patients whose tumors had a low expression of OPN were more likely to respond to chemotherapy and have a significantly better OS than those whose tumors had a high expression of OPN. Multivariate analysis revealed that prolonged survival was independently predicted for patients with stage IVA disease, negative lymph nodes, and negative expressions of OPN and for those who received chemotherapy with Docetaxel/cisplatin/fluorouracil (TPF). An oral cancer line stimulated with OPN exhibited a dose-dependent resistance to cisplatin treatment. Conversely, endogenous OPN depletion by OPN-mediated shRNA increased sensitivity to cisplatin. Conclusions. A positive expression of OPN predicts a poor response and survival in patients with locally advanced stage IVA/B OSCC treated with cisplatin-based IC followed by CCRT.

Osteopontin splice variants expression is involved on docetaxel resistance in PC3 prostate cancer cells

Osteopontin (OPN) is a phosphoprotein that activates several aspects of tumor progression. Alternative splicing of the OPN primary transcript generates three splicing isoforms, OPNa, OPNb and OPNc. In this report, we investigated some cellular mechanisms by which OPN splice variants could mediate PC3 prostate cancer (PCa) cell survival and growth in response to docetaxel (DXT)-induced cell death. Cell survival before and after DXT treatment was analyzed by phase-contrast microscopy and crystal-violet staining assays. Quantitative real-time PCR and immunocytochemical staining assays were used to evaluate the putative involvement of epithelial-mesenchymal transition (EMT) and OPN isoforms on mediating PC3 cell survival. Upon DXT treatment, PC3 cells overexpressing OPNb or OPNc isoforms showed higher cell densities, compared to cells overexpressing OPNa and controls. Notably, cells overexpressing OPNb or OPNc isoforms showed a downregulated pattern of EMT epithelial cell markers, while mesenchymal markers were mostly upregulated in these experimental conditions. We concluded that OPNc or OPNb overexpression in PC3 cells can mediate resistance and cell survival features in response to DXT-induced cell death. Our data also provide evidence the EMT program could be one of the molecular mechanisms mediating survival in OPNb- or OPNc-overexpressing cells in response to DXT treatment. These data could further contribute to a better understanding of the mechanisms by which PCa cells acquire resistance to DXT treatment.