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LOX expression and functional analysis in astrocytomas and impact of IDH1 mutation.

da Silva R, Uno M, Marie SK, Oba-Shinjo SM - PLoS ONE (2015)

Bottom Line: The results demonstrate that increased expression and activity of LOX, BMP1 and HIF1A were positively correlated with the malignant grade of astrocytomas.Glioblastoma with a mutation in IDH1 expressed lower levels of LOX in the nucleus, and IDH1-mutated cases showed lower LOX expression levels when compared to wild-type IDH1 cases.Taken together, these results corroborate the role of LOX in the migration, invasion and angiogenesis of astrocytomas.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular and Cellular Biology, Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, 01246-903, Brazil.

ABSTRACT
Lysyl oxidase (LOX) is involved in vital biological processes such as cell motility, cell signaling and gene regulation. Deregulation of this protein can contribute to tumor formation and progression. Although it is known that LOX is involved in invasion, proliferation and tumor migration in other types of tumors, studies of LOX in astrocytomas of different grades are scarce. The purpose of our study was to characterize LOX, BMP1 and HIF1A expression by real-time PCR in astrocytomas with WHO grades I to IV compared to non-neoplastic brain tissue. IDH1 mutational status was determined by PCR and sequencing. LOX protein expression was also analyzed by immunohistochemistry. LOX functional analyses were performed using siRNA knockdown and the specific inhibitor BAPN in two glioblastoma cell lines. The expression levels of LOX, BMP1 and HIF1A were correlated and analyzed according to IDH1 mutation status and to the clinical end-point of overall survival of glioblastoma patients. The results demonstrate that increased expression and activity of LOX, BMP1 and HIF1A were positively correlated with the malignant grade of astrocytomas. LOX protein expression also increased according to the degree of malignancy, with localization in the cytoplasm and nucleus and staining observed in endothelial cells. Glioblastoma with a mutation in IDH1 expressed lower levels of LOX in the nucleus, and IDH1-mutated cases showed lower LOX expression levels when compared to wild-type IDH1 cases. LOX knockdown and inhibition by BAPN in U87MG and A172 cell lines affected migration, invasion and soft agar colony formation. Taken together, these results corroborate the role of LOX in the migration, invasion and angiogenesis of astrocytomas. Furthermore, LOX expression is influenced by IDH1 mutational status. This work provides new insights for researchers aiming to design targeted therapies to control astrocytomas.

No MeSH data available.


Related in: MedlinePlus

Correlation of LOX, HIF1A and BMP1 expression levels in astrocytomas of different malignant grades.Correlation was assessed in pilocytic astrocytomas (AGI: A, B and C), low-grade astrocytomas (AGII: D, E and F), anaplastic astrocytomas (AGIII: G, H and I) and glioblastomas (GBM: J, K and L). Statistically significant values were obtained in AGI cases for BMP1 and HIF1A correlation (C) and in GBM cases for LOX and BMP1 correlation (J), LOX and HIF1A correlation (K) and HIF1A and BMP1 expression levels (L). In AGIII samples, HIF1A and LOX expression levels were negatively correlated (H). The statistically significant correlations are shown in red. Correlations between gene expression values were assessed using the non-parametric Spearman-rho correlation test.
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pone.0119781.g002: Correlation of LOX, HIF1A and BMP1 expression levels in astrocytomas of different malignant grades.Correlation was assessed in pilocytic astrocytomas (AGI: A, B and C), low-grade astrocytomas (AGII: D, E and F), anaplastic astrocytomas (AGIII: G, H and I) and glioblastomas (GBM: J, K and L). Statistically significant values were obtained in AGI cases for BMP1 and HIF1A correlation (C) and in GBM cases for LOX and BMP1 correlation (J), LOX and HIF1A correlation (K) and HIF1A and BMP1 expression levels (L). In AGIII samples, HIF1A and LOX expression levels were negatively correlated (H). The statistically significant correlations are shown in red. Correlations between gene expression values were assessed using the non-parametric Spearman-rho correlation test.

Mentions: LOX, BMP1 and HIF1A expression analysis by qRT-PCR showed great variability in astrocytomas of all malignant grades when compared to non-neoplastic samples. The GBM cases had higher LOX expression levels relative to non-neoplastic cases, with a statistically significant difference (Fig. 1A). No difference was found in LOX expression level between AGI, AGII and AGIII when compared to non-neoplastic samples. On the other hand, BMP1 expression levels were significantly higher in AGI and GBM groups when compared to non-neoplastic samples (Fig. 1B). HIF1A expression levels increased with the malignant grade of astrocytomas, with statistically significant values for all malignant grades of astrocytomas when compared to control samples (Fig. 1C). Coexpression of the three genes was compared for astrocytomas of all malignant grades (Fig. 2). Interestingly, Spearman analysis demonstrated that LOX mRNA levels were positively correlated with BMP1 and HIF1A in GBM (r = 0.217 and p = 0.045, Fig. 2J; r = 0.367 and p = 0.001, Fig. 2K, respectively). BMP1 expression also presented a positive correlation with HIF1A in GBM (r = 0.389; p<0.001) (Fig. 2L) and in AGI (r = 0.477; p = 0.033) (Fig. 2C). LOX, BMP1 and HIF1A expression levels were correlated with the clinical outcome of the GBM cases. The analysis of overall survival of GBM cases with high and low expression did not reveal a significant correlation between the gene expression data and the prognosis of GBM patients.


LOX expression and functional analysis in astrocytomas and impact of IDH1 mutation.

da Silva R, Uno M, Marie SK, Oba-Shinjo SM - PLoS ONE (2015)

Correlation of LOX, HIF1A and BMP1 expression levels in astrocytomas of different malignant grades.Correlation was assessed in pilocytic astrocytomas (AGI: A, B and C), low-grade astrocytomas (AGII: D, E and F), anaplastic astrocytomas (AGIII: G, H and I) and glioblastomas (GBM: J, K and L). Statistically significant values were obtained in AGI cases for BMP1 and HIF1A correlation (C) and in GBM cases for LOX and BMP1 correlation (J), LOX and HIF1A correlation (K) and HIF1A and BMP1 expression levels (L). In AGIII samples, HIF1A and LOX expression levels were negatively correlated (H). The statistically significant correlations are shown in red. Correlations between gene expression values were assessed using the non-parametric Spearman-rho correlation test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4366168&req=5

pone.0119781.g002: Correlation of LOX, HIF1A and BMP1 expression levels in astrocytomas of different malignant grades.Correlation was assessed in pilocytic astrocytomas (AGI: A, B and C), low-grade astrocytomas (AGII: D, E and F), anaplastic astrocytomas (AGIII: G, H and I) and glioblastomas (GBM: J, K and L). Statistically significant values were obtained in AGI cases for BMP1 and HIF1A correlation (C) and in GBM cases for LOX and BMP1 correlation (J), LOX and HIF1A correlation (K) and HIF1A and BMP1 expression levels (L). In AGIII samples, HIF1A and LOX expression levels were negatively correlated (H). The statistically significant correlations are shown in red. Correlations between gene expression values were assessed using the non-parametric Spearman-rho correlation test.
Mentions: LOX, BMP1 and HIF1A expression analysis by qRT-PCR showed great variability in astrocytomas of all malignant grades when compared to non-neoplastic samples. The GBM cases had higher LOX expression levels relative to non-neoplastic cases, with a statistically significant difference (Fig. 1A). No difference was found in LOX expression level between AGI, AGII and AGIII when compared to non-neoplastic samples. On the other hand, BMP1 expression levels were significantly higher in AGI and GBM groups when compared to non-neoplastic samples (Fig. 1B). HIF1A expression levels increased with the malignant grade of astrocytomas, with statistically significant values for all malignant grades of astrocytomas when compared to control samples (Fig. 1C). Coexpression of the three genes was compared for astrocytomas of all malignant grades (Fig. 2). Interestingly, Spearman analysis demonstrated that LOX mRNA levels were positively correlated with BMP1 and HIF1A in GBM (r = 0.217 and p = 0.045, Fig. 2J; r = 0.367 and p = 0.001, Fig. 2K, respectively). BMP1 expression also presented a positive correlation with HIF1A in GBM (r = 0.389; p<0.001) (Fig. 2L) and in AGI (r = 0.477; p = 0.033) (Fig. 2C). LOX, BMP1 and HIF1A expression levels were correlated with the clinical outcome of the GBM cases. The analysis of overall survival of GBM cases with high and low expression did not reveal a significant correlation between the gene expression data and the prognosis of GBM patients.

Bottom Line: The results demonstrate that increased expression and activity of LOX, BMP1 and HIF1A were positively correlated with the malignant grade of astrocytomas.Glioblastoma with a mutation in IDH1 expressed lower levels of LOX in the nucleus, and IDH1-mutated cases showed lower LOX expression levels when compared to wild-type IDH1 cases.Taken together, these results corroborate the role of LOX in the migration, invasion and angiogenesis of astrocytomas.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular and Cellular Biology, Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, 01246-903, Brazil.

ABSTRACT
Lysyl oxidase (LOX) is involved in vital biological processes such as cell motility, cell signaling and gene regulation. Deregulation of this protein can contribute to tumor formation and progression. Although it is known that LOX is involved in invasion, proliferation and tumor migration in other types of tumors, studies of LOX in astrocytomas of different grades are scarce. The purpose of our study was to characterize LOX, BMP1 and HIF1A expression by real-time PCR in astrocytomas with WHO grades I to IV compared to non-neoplastic brain tissue. IDH1 mutational status was determined by PCR and sequencing. LOX protein expression was also analyzed by immunohistochemistry. LOX functional analyses were performed using siRNA knockdown and the specific inhibitor BAPN in two glioblastoma cell lines. The expression levels of LOX, BMP1 and HIF1A were correlated and analyzed according to IDH1 mutation status and to the clinical end-point of overall survival of glioblastoma patients. The results demonstrate that increased expression and activity of LOX, BMP1 and HIF1A were positively correlated with the malignant grade of astrocytomas. LOX protein expression also increased according to the degree of malignancy, with localization in the cytoplasm and nucleus and staining observed in endothelial cells. Glioblastoma with a mutation in IDH1 expressed lower levels of LOX in the nucleus, and IDH1-mutated cases showed lower LOX expression levels when compared to wild-type IDH1 cases. LOX knockdown and inhibition by BAPN in U87MG and A172 cell lines affected migration, invasion and soft agar colony formation. Taken together, these results corroborate the role of LOX in the migration, invasion and angiogenesis of astrocytomas. Furthermore, LOX expression is influenced by IDH1 mutational status. This work provides new insights for researchers aiming to design targeted therapies to control astrocytomas.

No MeSH data available.


Related in: MedlinePlus