Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite advances in the management of osteosarcoma (OSA) and other solid tumors, the development of metastasis continues to be the most significant problem and cause of death for cancer patients. To define genetic determinants of pulmonary metastasis, we have applied cDNA microarrays to a recently described murine model of OSA that is characterized by orthotopic tumor growth, a period of minimal residual disease, spontaneous pulmonary metastasis, and cell line variants that differ in metastatic potential. Microarray analysis defined 53 genes (of 3166 unique cDNAs) that were differentially expressed between the primary tumors of the more aggressive (K7M2) and less aggressive (K12) OSA models. By review of the literature, these differentially expressed genes were assigned to six nonmutually exclusive metastasis-associated categories (proliferation and apoptosis, motility and cytoskeleton, invasion, immune surveillance, adherence, and angiogenesis). Functional studies to evaluate K7M2 and K12 for differences in each of these metastasis-associated processes revealed enhanced motility, adherence, and angiogenesis in the more aggressive K7M2 model. For this reason, 10 of the 53 differentially expressed genes that were assigned to the motility and cytoskeleton, adherence, and angiogenesis categories were considered as most likely to define differences in the metastatic behavior of the two models. Ezrin, a gene not described previously in OSA, with functions in motility, invasion, and adherence, was 3-fold overexpressed in K7M2 compared with K12 by microarray. Differential expression for RNA was confirmed by Northern analysis and for protein by immunostaining. Alterations in ezrin protein levels and concomitant cytoskeletal changes in our model confirmed predictions from the arrays. The potential relevance of ezrin in OSA was suggested by its expression in five of five human OSA cell lines. This work represents a rationale approach to the evaluation of microarray data and will be useful to identify genes that may be causally associated with metastasis.
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PMID:Metastasis-associated differences in gene expression in a murine model of osteosarcoma. 1132 48

The aims of this pilot study were to determine whether needle and open biopsies from osteosarcoma (OS) provide sufficient quality of mRNA for cDNA array analyses to gain insights into the expression profile of OS. A total of 22 samples collected from OS were used for array analyses. A primary cell culture was also established from one of the OS biopsies. Total RNA was extracted and probes were generated for cDNA arrays. cDNA probes were made for all the 22 samples. Two of these samples were needle core bone biopsies. Statistical analysis confirmed the reliability of array data obtained in 16 of the 22 samples. Known genes involved in bone metabolism and osteosarcoma were identified as highly expressed, and the putative new marker Ezrin was also identified. Confirmatory immunohistochemical staining using the Ezrin antibody was performed in a selection of samples.
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PMID:Gene expression array profile of human osteosarcoma. 1467 7

Metastatic cancers, once established, are the primary cause of mortality associated with cancer. Previously, we used a genomic approach to identify metastasis-associated genes in cancer. From this genomic data, we selected ezrin for further study based on its role in physically and functionally connecting the actin cytoskeleton to the cell membrane. In a mouse model of osteosarcoma, a highly metastatic pediatric cancer, we found ezrin to be necessary for metastasis. By imaging metastatic cells in the lungs of mice, we showed that ezrin expression provided an early survival advantage for cancer cells that reached the lung. AKT and MAPK phosphorylation and activity were reduced when ezrin protein was suppressed. Ezrin-mediated early metastatic survival was partially dependent on activation of MAPK, but not AKT. To define the relevance of ezrin in the biology of metastasis, beyond the founding mouse model, we examined ezrin expression in dogs that naturally developed osteosarcoma. High ezrin expression in dog tumors was associated with early development of metastases. Consistent with this data, we found a significant association between high ezrin expression and poor outcome in pediatric osteosarcoma patients.
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PMID:The membrane-cytoskeleton linker ezrin is necessary for osteosarcoma metastasis. 1470 91

Identification of the key regulatory molecules in metastasis is crucial for understanding tumor dissemination and for the development of novel interventions. The recent identification of ezrin as a necessary component in the metastasis of osteosarcoma and rhabdomyosarcoma is, therefore, an important advance. Ezrin has been implicated in many roles, for example, as a conduit for signals between metastasis-associated cell-surface molecules and signal transduction components. This suggests that ezrin and, potentially, other members of the ERM (ezrin-radixin-moesin) family have key roles in the coordination of signals and cellular complexes that are required for the successful metastasis of these and other malignancies.
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PMID:Ezrin, a key component in tumor metastasis. 1517 87

To search for the intracellular signaling pathway critical for the pulmonary metastasis of osteosarcoma, we examined two osteosarcoma cell lines with different metastatic capability, Dunn and LM8. While parental Dunn is poorly metastatic to lung, LM8, derived from Dunn by in vivo selection through pulmonary metastasis, displays clear capability of pulmonary metastasis. We found that LM8 had higher levels of Akt phosphorylation and Ezrin expression than Dunn. In contrast, no clear difference was observed between Dunn and LM8 in other signaling mediators, including MAPK, SAPK and Stat3. In contrast to Dunn, LM8 secreted higher levels of matrix metalloproteinase-2 and -9, showed higher levels of invasiveness and cell motility, and displayed strong pulmonary metastasis. Inhibition of PI3K-Akt signaling in LM8 by a PI3K inhibitor, LY294002, or by a dominant negative form of Akt, resulted in suppression of MMP secretion, in vitro invasiveness, cell locomotion and in vivo pulmonary metastasis. In contrast, expression of an active form of Akt in Dunn substantially activated its MMP secretion, in vitro invasiveness, cell locomotion and in vivo pulmonary metastasis. Taken together, our results demonstrate, for the first time, an important role of Akt signaling in pulmonary metastasis of osteosarcoma.
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PMID:A role for PI3K-Akt signaling in pulmonary metastatic nodule formation of the osteosarcoma cell line, LM8. 1614 41

Ezrin is a cytoskeleton linker protein that is actively involved in the regulation of growth and metastatic capacity of cancer cells. Recently, it has been demonstrated that a significant correlation exists between high ezrin expression levels and the poor outcome of pediatric osteosarcoma patients. The expression of ezrin was compared in conventional high-grade and central low-grade osteosarcoma lesions to investigate the role of ezrin overexpression in the metastasis of osteosarcoma. We compared the expression levels of the ezrin protein in 32 cases of high-grade osteosarcomas and 21 cases of low-grade osteosarcomas using immunohistochemistry. Ezrin protein expression levels were examined in three different human osteosarcoma cell lines by Western blotting. In addition, the mRNA expression levels of ezrin in these osteosarcoma cell lines and control fibroblasts were evaluated by real-time quantitative PCR. Ezrin immunoreactivity was present in 43.7% of high-grade osteosarcoma specimens. All low-grade osteosarcomas were negative for ezrin. The expression of ezrin was detected by Western blotting in all three osteosarcoma cell lines. The tested osteosarcoma cell lines showed marked amplification of ezrin mRNA compared to control cells. Taken together, ezrin appears to play a role in the progression of tumors, such as the metastasis of osteosarcoma. However, further data are needed before ezrin can be considered in clinical decision-making about osteosarcoma patients.
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PMID:Ezrin in osteosarcoma: comparison between conventional high-grade and central low-grade osteosarcoma. 1667 79

Ezrin, a cytoskeleton linker protein, has been reported to be involved in the metastasis of solid tumors in animal models and patients in small clinical studies. We analyzed the relationship between immunohistochemical expression of ezrin and the prognosis of osteosarcoma. We retrospectively identified 64 patients with Stage IIB osteosarcomas between 1995 and 2000. Tissue microarrays were constructed from incisional biopsy specimens and immunohistochemical staining was performed. Ezrin expression and other clinicopathologic variables such as age, gender, pathologic subtype, tumor size and location, and histologic response were compared with outcomes. The minimum followup was 12 months (mean, 78.2 months; range, 12-137 months). Twenty-three of 64 patients (35.9%) showed late distant metastasis; 33 of 64 patients (51.6%) showed expression of ezrin, and of these 33 patients, 22 (66.7%) had distant metastasis develop. Multivariate analysis revealed histologic response to preoperative chemotherapy and expression of ezrin predicted disease-free survival. Expression of ezrin in osteosarcoma biopsy specimens is promising as a marker to predict outcome in patients with osteosarcoma.
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PMID:Ezrin expression predicts survival in stage IIB osteosarcomas. 1735 2

Osteosarcoma (OS) remains a life-threatening malignancy and its molecular character is not fully understood. Ezrin is a cytoskeleton linker protein involved in regulating the growth and metastatic capacity of cancer cells. However, the correlation between ezrin mRNA expression and clinical severity has not yet been examined in OS biopsy samples. Furthermore, recent evidence has demonstrated that the level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression is increased in human cancers of various origins, but this has not yet been examined in OS cells. To clarify the correlation between the clinical severity and the levels of ezrin and GAPDH mRNA expression, we quantified these mRNA levels in 4 pediatric OS biopsy samples using real-time quantitative polymerase chain reaction. Among these 4 samples, ezrin mRNA expression was approximately 5-fold higher in a case with lung metastasis compared with the other cases without metastasis, suggesting an association between the ezrin mRNA expression level and metastasis. On the other hand, the GAPDH mRNA expression level was not related to the clinical severity. This is the first report to demonstrate a high level of ezrin mRNA expression in an OS biopsy sample with lung metastasis.
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PMID:High level of ezrin mRNA expression in an osteosarcoma biopsy sample with lung metastasis. 1760 19

Ezrin is a cytoskeleton linker protein that is actively involved in the metastatic process of cancer cells. We have searched for a prognostic value of ezrin and some of its partners: alpha-smooth muscle actin and CD44H in 37 patients with an osteosarcoma. Automate immunohistochemistry (IHC) with anti-ezrin, alpha-smooth muscle actin and CD44H antibodies was performed in 66 specimens: 37 biopsies before chemotherapy, 16 resected tumours of "poor" responders and 13 metastases. The messenger RNA (mRNA) levels of ezrin of 13 frozen biopsies and 4 metastases were evaluated by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). All results were correlated to the following clinical data. Ezrin expression by IHC was found in 62% of 37 biopsies in the different histological subtypes. A good correlation was found between positive or negative samples by IHC and mRNA levels. Ezrin expression was recorded in 84.5% of metastastic samples. The mean expression of ezrin was higher in metastases than biopsies (p = 0.024). In multivariate analysis, ezrin was an independent prognostic marker for event-free survival and overall survival (OS) with p < 0.001 and p = 0.003, respectively, and alpha-smooth muscle actin for OS only (p = 0.024). Our findings suggest that ezrin and alpha-smooth muscle actin are predictive IHC prognostic markers for patients with an osteosarcoma.
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PMID:Ezrin and alpha-smooth muscle actin are immunohistochemical prognostic markers in conventional osteosarcomas. 1778 74

The role of Gemin5 in alternative mRNA splicing, tumor cell motility, and proteomic instability was investigated. Isotope Capture Affinity Tag proteomic analysis was conducted on MDA-MB-435 tumor cells transfected with either a control vector (C-100) or the Nm23-H1 metastasis suppressor (H1-177). Ingenuity pathway analysis revealed that RNA posttranscriptional processing was the most prominent class of differentially expressed proteins. Within this category, overexpression of Acinus1, Poly(a) binding protein, HNRPA2B1, Bop1, and Gemin5 was confirmed in less metastatic H1-177 cells. Overexpression of the latter four proteins was also observed in the lower metastatic antisense Ezrin transfectant of a murine osteosarcoma model system, confirming the general relevance of the trends. Gemin5, a component of the spliceosomal complex, was chosen for further study. Analysis of global mRNA splicing by SpliceArray chips revealed that 16 genes were differentially spliced in C-100 compared with H1-177 cells; transient transfection of gemin5 into C-100 cells restored the splice pattern to that of H1-177 cells. Alternative splicing patterns for the engulfment and cell motility 1 and thrombospondin 4 genes were confirmed by semiquantitative reverse transcription-PCR. Gemin5 overexpression coordinately reduced C-100 cell motility by 50%, and siRNA-mediated reduction of Gemin5 expression increased the motility of H1-177 cells by 2-fold (P < 0.004). The data provide the first demonstration that alterations in the expression of a spliceosome protein can effect both specific splicing events and tumor cell motility. The data also show that changes in mRNA splicing patterns accompany metastatic progression, which may contribute to proteome instability.
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PMID:Alterations in Gemin5 expression contribute to alternative mRNA splicing patterns and tumor cell motility. 1824 61


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