Nives Pećina-Šlaus1, Anja Kafka2, Tomislav Vladušić3, Hrvoje Ivan Pećina4, Reno Hrašćan3. 1. Laboratory of Neurooncology, Croatian Institute for Brain Research, School of Medicine University of Zagreb, Zagreb, Croatia Department of Biology, School of Medicine, University of Zagreb, Zagreb, Croatia nina@mef.hr. 2. Laboratory of Neurooncology, Croatian Institute for Brain Research, School of Medicine University of Zagreb, Zagreb, Croatia Department of Biology, School of Medicine, University of Zagreb, Zagreb, Croatia. 3. Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia. 4. Department of Radiology, Hospital Center "Sisters of Mercy", Zagreb, Croatia.
Abstract
BACKGROUND/AIM: Tumor suppressor gene AXIN1 is an inhibitor of Wnt signaling pathway. It down-regulates the pathway's main signaling effector molecule, beta-catenin, in an AXIN-based destruction complex. In the present study we investigated the involvement of AXIN1 in intracranial meningioma. MATERIALS AND METHODS: Loss of heterozygosity and microsatellite instability analyses were performed. The consequences of genetic changes on protein expression levels were studied in the same patients by immunohistochemistry. RESULTS: Allelic deletions of AXIN1 gene were found in 21.1% of meningiomas. Microsatellite instability was also observed in 5.3% of cases. Weak or lack of AXIN1 expression was found in 21.9% of meningiomas. We found strong statistical correlations between cytoplasmic localization of AXIN1 and its weak expression and also between the simultaneous cytoplasmic and nuclear localizations and moderate and strong expression levels (p<0.000). The findings on AXIN1 were compared to concomitant expression of APC, beta-catenin and E-cadherin in the same patients by Chi-Square tests and Pearson's correlations. Analysis revealed that AXIN1 genetic changes were significantly associated to lack of the expression of APC and presence of mutant APC proteins (p<0.018). Moderate and strong cytoplasmic and nuclear AXIN1 expressions were positively correlated to strong expression of E-cadherin (p<0.05). CONCLUSION: Our findings on genetic changes and expression levels of AXIN1 bring novel data on its involvement in meningeal brain tumors and reveal AXIN1's relation to specific Wnt molecules. Copyright
BACKGROUND/AIM: Tumor suppressor gene AXIN1 is an inhibitor of Wnt signaling pathway. It down-regulates the pathway's main signaling effector molecule, beta-catenin, in an AXIN-based destruction complex. In the present study we investigated the involvement of AXIN1 in intracranial meningioma. MATERIALS AND METHODS: Loss of heterozygosity and microsatellite instability analyses were performed. The consequences of genetic changes on protein expression levels were studied in the same patients by immunohistochemistry. RESULTS: Allelic deletions of AXIN1 gene were found in 21.1% of meningiomas. Microsatellite instability was also observed in 5.3% of cases. Weak or lack of AXIN1 expression was found in 21.9% of meningiomas. We found strong statistical correlations between cytoplasmic localization of AXIN1 and its weak expression and also between the simultaneous cytoplasmic and nuclear localizations and moderate and strong expression levels (p<0.000). The findings on AXIN1 were compared to concomitant expression of APC, beta-catenin and E-cadherin in the same patients by Chi-Square tests and Pearson's correlations. Analysis revealed that AXIN1 genetic changes were significantly associated to lack of the expression of APC and presence of mutant APC proteins (p<0.018). Moderate and strong cytoplasmic and nuclear AXIN1 expressions were positively correlated to strong expression of E-cadherin (p<0.05). CONCLUSION: Our findings on genetic changes and expression levels of AXIN1 bring novel data on its involvement in meningeal brain tumors and reveal AXIN1's relation to specific Wnt molecules. Copyright