骨肉瘤是一类易转移，预后差的恶性骨肿瘤。深入理解骨肉瘤的转移机制对改善其治疗和预后有重要意义。我们通过骨肉瘤组织转录组测序，鉴定了细胞外基质糖蛋白PCPE-1在癌组织中表达显著高于癌旁组织。预实验显示：敲低/过表达PCPE-1能显著抑制/促进骨肉瘤细胞的迁移、侵袭和转移；PCPE-1的Asn29位点糖基化能够调控其蛋白稳定性、分泌过程，该糖基化可能受糖基转移酶ST6GALNAC3调控；EMT的关键调控因子TWIST1可转录激活PCPE-1表达。本项目拟：细胞水平、动物模型中进一步验证PCPE-1促进骨肉瘤转移的功能；研究PCPE-1的Asn29位点糖基化在骨肉瘤转移中的作用，并阐明其机制；进一步明确骨肉瘤细胞中TWIST1转录激活PCPE-1表达；探讨该TWIST1/PCPE-1通路在骨肉瘤患者中的临床价值。本项目的完成，将为骨肉瘤的诊断治疗提供新的靶标或思路。

Osteosarcoma is one of the most malignant bone tumors, and tends to metastasize to lung with poor prognosis. The deeply understanding of mechanism of metastasis is necessary for improving the treatment and prognosis of patients with osteosarcoma. We have recently performed the RNAseq by using osteosarcoma tissues, and found that procollagen C-proteinase enhancer protein (PCPE-1) was markedly up-regulated in human osteosarcoma tissues compared to non-cancerous adjacent tissues. Our preliminary results showed that knockdown or overexpression of PCPE-1 impaired or promoted migration, invasion and the lung metastasis of osteosarcoma cells. The Asn29 N-glycosylation of PCPE-1 positively regulated its protein stability and its secretion, and that this glycosylation may be modulated by ST6GALNAC3. TWIST1 as a key regulator in EMT was able to transcriptionally up-regulate PCPE-1 in osteosarcoma cells. This proposal plans to investigate the following events: To further confirm that PCPE-1 promotes metastasis of osteosarcoma cells in vitro and in vivo; To investigate the function and mechanism of Asn29 N-linked glycosylation modification of PCPE-1 in osteosarcoma cells; To further confirm that TWIST1 transcriptionally up-regulates PCPE-1 in osteosarcoma cells. To explore the clinical significance of TWIST/PCPE-1 signaling axis in patients with osteosarcoma. We believe that this proposal will provide a novel diagnostic biomarker or therapeutic strategy for patients with osteosarcoma