Urciuoli Enrica, Coletta Ilenia, Rizzuto Emanuele, De Vito Rita, Petrini Stefania, D'Oria Valentina, Pezzullo Marco, Milano Giuseppe Maria, Cozza Raffaele, Locatelli Franco, Peruzzi Barbara
Research Laboratories, Bambino Gesù Children's Hospital, Rome, Italy.
DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy.
J Cell Physiol. 2018 Feb;233(2):1658-1670. doi: 10.1002/jcp.26079. Epub 2017 Aug 17.
Osteosarcoma is the most common malignant bone tumor in children and young adults. The identification of proteins which exhibit different subcellular localization in low- versus high-risk osteosarcoma can be instrumental to obtain prognostic information and to develop innovative therapeutic strategies. Beside the well-characterized membrane and cytoplasmic localization of Src protein, this study evaluated the prognostic relevance of its so-far unknown nuclear compartmentalization. We analyzed the subcellular distribution of total and activated (pY418) Src in a tissue microarray including 60 osteosarcoma samples. Immunohistochemical analyses revealed a variable pattern of Src expression and localization, ranging from negative to high-stained nuclei combined with a substantial cytoplasmic staining for total and activated forms. The analysis of Kaplan-Meier survival curves in relationship to the diverse permutations of cytoplasmic and nuclear staining suggested a correlation between Src subcellular localization and the overall survival (OS) of osteosarcoma patients. In order to explain this different subcellular localization, normal osteoblasts and three osteosarcoma cell lines were used to investigate the molecular mechanism. Once confirmed a variable Src localization also in these cell lines, we demonstrated a correlation between the N-myristoyltransferase enzymes expression and activity and the Src nuclear content. In conclusion, these results described a so-far unknown Src nuclear localization in osteosarcoma cells, suggesting that the combined detection of nuclear and cytoplasmic Src levels can be used as a prognostic marker for osteosarcoma patient survival. A correlation between the N-myristoyltransferase enzymes and the Src subcellular localization was described as well.
骨肉瘤是儿童和青年中最常见的恶性骨肿瘤。鉴定在低风险与高风险骨肉瘤中表现出不同亚细胞定位的蛋白质，有助于获取预后信息并制定创新的治疗策略。除了已明确的Src蛋白的膜和细胞质定位外，本研究评估了其迄今未知的核定位的预后相关性。我们在包含60个骨肉瘤样本的组织微阵列中分析了总Src和活化型（pY418）Src的亚细胞分布。免疫组织化学分析显示Src表达和定位模式各异，从细胞核阴性到高染色，同时总形式和活化形式在细胞质中也有大量染色。对Kaplan-Meier生存曲线与细胞质和细胞核染色的不同排列组合进行分析，提示Src亚细胞定位与骨肉瘤患者的总生存期（OS）之间存在相关性。为了解释这种不同的亚细胞定位，我们使用正常成骨细胞和三种骨肉瘤细胞系来研究分子机制。一旦证实这些细胞系中Src定位也存在差异，我们证明了N-肉豆蔻酰转移酶的表达和活性与Src核含量之间存在相关性。总之，这些结果描述了骨肉瘤细胞中迄今未知的Src核定位，表明联合检测细胞核和细胞质中Src水平可作为骨肉瘤患者生存的预后标志物。同时还描述了N-肉豆蔻酰转移酶与Src亚细胞定位之间的相关性。
