RESUMO
Analyzing molecular biomarkers using blood is an important approach for clinical assessment of malignant glioma. We investigated a molecular proteomic biomarker-based approach for glioblastoma using patients' blood samples. The expression levels of a list of candidate proteins were quantified in plasma and serum samples from two different cohorts of patients with malignant glioma and normal controls. The biological function was studied for one of the identified markers. Additionally, the prognostic significance of protein marker expression was measured by survival analysis. As a result, protein biomarkers associated with malignant glioma were identified from the blood specimens and five of the protein biomarkers were common to both cohorts. Immunohistochemical analysis demonstrated that many of the protein biomarkers identified in peripheral blood specimens were expressed in malignant gliomas. Staining levels for one of the biomarkers, MIP-1α, was found to correlate with WHO grade among invasive gliomas, and we demonstrate that MIP-1α promotes human glioblastoma cell proliferation and migration. Additionally, four prognostic protein biomarkers were identified. In conclusion, we demonstrate that both peripheral blood plasma and serum specimens are highly valuable and complementary to each other in the quest for protein biomarkers of malignant glioma. Sets of novel protein biomarkers were identified that may aid in the diagnosis and prognosis of patients with malignant glioma.
Assuntos
Biomarcadores Tumorais/sangue , Proteínas Sanguíneas/metabolismo , Neoplasias do Sistema Nervoso Central/sangue , Quimiocina CCL3/sangue , Glioma/sangue , Adulto , Idoso , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Proteínas Sanguíneas/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Neoplasias do Sistema Nervoso Central/metabolismo , Neoplasias do Sistema Nervoso Central/mortalidade , Neoplasias do Sistema Nervoso Central/patologia , Quimiocina CCL3/genética , Quimiocina CCL3/metabolismo , Estudos de Coortes , Feminino , Expressão Gênica , Glioma/metabolismo , Glioma/mortalidade , Glioma/patologia , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Curva ROC , Estatísticas não ParamétricasRESUMO
UNLABELLED: Tumor microenvironment constitutes a reservoir for proteins released from tumor cells and the host, which can contribute significantly to tumor growth and invasion. This study aims to apply a method of combining in vivo microdialysis and proteomics to identify proteins in mammary tumor interstitial fluids, a major component of tumor microenvironment. In vivo microdialysis was performed in polyomavirus middle T antigen (PyVmT) transgenic mouse mammary tumors and age-matched control wild-type mammary glands. Over four hundred proteins were identified from the microdialysis perfusates, using the Multidimensional Protein Identification Technology. Osteopontin (OPN) is one of the proteins overexpressed in breast tumor perfusates, as confirmed with immunoassays. OPN was also found to be present in tumor-associated stroma in both PyVmT and human breast tumors, using immunohistochemistry. Specifically, fibroblasts were further shown to express OPN at both mRNA and protein levels. In vitro assays showed that OPN can stimulate PyVmT breast carcinoma cell proliferation and migration. Finally, the expression of OPN was significantly higher in the peripheral blood of mice bearing breast tumors, compared to wild-type mice. Overall, microdialysis combined with proteomics is a unique technique for identifying proteins in a tumor microenvironment in vivo. Mammary fibroblasts can secrete OPN, and its overexpression in mammary tumor microenvironment may contribute significantly to mammary tumor progression. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12307-010-0046-3) contains supplementary material, which is available to authorized users.
