Abstract：
OBJECTIVE: Chordomas are malignant tumors that destroy bones, compress surrounding nerve tissues and exhibit phenotypes that recapitulate notochordal differentiation in the axial skeleton. Chordomas recur frequently, as they resist radio-chemotherapy and are difficult to completely resect, leading to repeated bone destruction and local expansion via unknown mechanisms. Here, using chordoma specimens and JHC7 chordoma cells, we asked whether chordoma cells possess bone-dissolving activity.
METHODS: CT imaging and histological analysis were performed to evaluate the structure and mineral density of chordoma-invaded bone and osteolytic marker expression. JHC7 cells were subjected to immunocytochemistry, imaging of cell fusion, calcium dynamics and acidic vacuoles, and bone lysis assays.
RESULTS: In patients, we found that the skull base invaded by chordoma was highly porous, showed low mineral density and contained brachyury-positive chordoma cells and conventional osteoclasts both expressing the osteolytic markers tartrate-resistant acid phosphatase (TRAP) and collagenases. JHC7 cells expressed TRAP and cathepsin K, became multinucleated via cell-cell fusion, showed spontaneous calcium oscillation, and were partly responsive to the osteoclastogenic cytokine RANKL. JHC7 cells exhibited large acidic vacuoles, and nonregulatory bone degradation without forming actin rings. Finally, bone-derived factors, calcium ions, TGF-β1, and IGF-1 enhanced JHC7 cell proliferation.
CONCLUSIONS: In chordoma, we propose that in addition to conventional bone resorption by osteoclasts, chordoma cells possess bone-dissolving activity at the tumor-bone boundary. Furthermore, bone destruction and tumor expansion may occur in a positive feedback loop.
METHODS: CT imaging and histological analysis were performed to evaluate the structure and mineral density of chordoma-invaded bone and osteolytic marker expression. JHC7 cells were subjected to immunocytochemistry, imaging of cell fusion, calcium dynamics and acidic vacuoles, and bone lysis assays.
RESULTS: In patients, we found that the skull base invaded by chordoma was highly porous, showed low mineral density and contained brachyury-positive chordoma cells and conventional osteoclasts both expressing the osteolytic markers tartrate-resistant acid phosphatase (TRAP) and collagenases. JHC7 cells expressed TRAP and cathepsin K, became multinucleated via cell-cell fusion, showed spontaneous calcium oscillation, and were partly responsive to the osteoclastogenic cytokine RANKL. JHC7 cells exhibited large acidic vacuoles, and nonregulatory bone degradation without forming actin rings. Finally, bone-derived factors, calcium ions, TGF-β1, and IGF-1 enhanced JHC7 cell proliferation.
CONCLUSIONS: In chordoma, we propose that in addition to conventional bone resorption by osteoclasts, chordoma cells possess bone-dissolving activity at the tumor-bone boundary. Furthermore, bone destruction and tumor expansion may occur in a positive feedback loop.
摘要：
目的：脊索瘤是破坏骨骼的恶性肿瘤，压缩周围的神经组织，并表现出在中轴骨骼中概括脊索分化的表型。脊索瘤经常复发，因为它们抵抗放化疗并且很难完全切除，通过未知机制导致反复的骨破坏和局部扩张。这里,使用脊索瘤标本和JHC7脊索瘤细胞，我们询问脊索瘤细胞是否具有骨溶解活性。
方法：进行CT成像和组织学分析，以评估脊索瘤侵袭骨的结构和矿物质密度以及溶骨标志物的表达。对JHC7细胞进行免疫细胞化学，细胞融合成像，钙动力学和酸性液泡，和骨溶解试验。
结果：在患者中，我们发现脊索瘤侵入的颅底是高度多孔的，表现出低矿物质密度，并含有短枝阳性脊索瘤细胞和常规破骨细胞，均表达溶骨标志物抗酒石酸酸性磷酸酶（TRAP）和胶原酶。JHC7细胞表达TRAP和组织蛋白酶K,通过细胞-细胞融合变成多核，显示自发的钙振荡，部分对破骨细胞细胞因子RANKL有反应。JHC7细胞显示大的酸性液泡，和不形成肌动蛋白环的非调节性骨降解。最后,骨源性因子，钙离子，TGF-β1和IGF-1增强JHC7细胞增殖。
结论：在脊索瘤中，我们认为，除了破骨细胞的常规骨吸收外，脊索瘤细胞在肿瘤-骨边界具有骨溶解活性。此外，骨破坏和肿瘤扩张可能发生在一个正反馈回路中。
方法：进行CT成像和组织学分析，以评估脊索瘤侵袭骨的结构和矿物质密度以及溶骨标志物的表达。对JHC7细胞进行免疫细胞化学，细胞融合成像，钙动力学和酸性液泡，和骨溶解试验。
结果：在患者中，我们发现脊索瘤侵入的颅底是高度多孔的，表现出低矿物质密度，并含有短枝阳性脊索瘤细胞和常规破骨细胞，均表达溶骨标志物抗酒石酸酸性磷酸酶（TRAP）和胶原酶。JHC7细胞表达TRAP和组织蛋白酶K,通过细胞-细胞融合变成多核，显示自发的钙振荡，部分对破骨细胞细胞因子RANKL有反应。JHC7细胞显示大的酸性液泡，和不形成肌动蛋白环的非调节性骨降解。最后,骨源性因子，钙离子，TGF-β1和IGF-1增强JHC7细胞增殖。
结论：在脊索瘤中，我们认为，除了破骨细胞的常规骨吸收外，脊索瘤细胞在肿瘤-骨边界具有骨溶解活性。此外，骨破坏和肿瘤扩张可能发生在一个正反馈回路中。
