B4GALNT1表达下调抑制骨肉瘤细胞增殖和转移

Downregulation of B4GALNT1 inhibits proliferation and metastasis of osteosarcoma cells

目的:骨肉瘤是儿童和青少年最常见的骨恶性肿瘤,具有极强的增殖和转移潜能。伴有远处转移的骨肉瘤患者的生存预后极差,且骨肉瘤患者在治疗过程中易出现病灶切除不彻底、化学治疗耐药等难题,目前尚缺乏有效的根治手段。近年来,越来越多的证据表明β-1,4-N-乙酰半乳糖氨基转移酶1(β-1,4-N-acetylgalactosaminyltransferase 1,B4GALNT1)能够影响多种恶性肿瘤的进展。然而,B4GALNT1在骨肉瘤细胞中的功能却未见报道。本研究拟探讨骨肉瘤组织与正常组织中B4GALNT1的表达以及B4GALNT1对骨肉瘤细胞增殖、迁移和侵袭的影响,以期为骨肉瘤患者的治疗提供新的理论依据和方向。方法:收集在中南大学湘雅二医院行骨肉瘤瘤段切除的16例患者的肿瘤组织及相对应的正常组织样本,骨肉瘤患者的年龄为8~17(中位数12)岁。利用实时反转录聚合酶链反应(real-time reverse transcription PCR,real-time RT-PCR)检测B4GALNT1 mRNA在骨肉瘤组织、相对应的正常组织、3种骨肉瘤细胞系(MG63、Saos-2、U2OS)及人成骨细胞(human fetal osteoblastic,hFOB)中的表达情况;通过细胞计数试剂盒-8(cell counting kit-8,CCK-8)及克隆形成实验分析敲减B4GALNT1对骨肉瘤细胞Saos-2及U2OS增殖能力的影响;利用Transwell迁移和侵袭实验分析敲减B4GALNT1对骨肉瘤细胞Saos-2及U2OS迁移和侵袭能力的影响;使用蛋白质印迹法分析敲减B4GALNT1对Saos-2及U2OS细胞上皮-间充质转化(epithelial-mesenchymal transition,EMT)及侵袭相关蛋白质表达的影响。结果:Real-time RT-PCR结果表明:与正常组织及h FOB相比,骨肉瘤组织和3种骨肉瘤细胞系中B4GALNT1 mRNA的表达水平较高(均P<0.01)。CCK-8及克隆形成实验结果表明:与对照组相比,敲减B4GALNT1降低了骨肉瘤细胞的增殖速率(均P<0.05)。Transwell迁移和侵袭实验结果表明:与对照组相比,敲减B4GALNT1减少了骨肉瘤细胞的迁移和侵袭细胞数(均P<0.01)。蛋白质印迹结果表明:与对照组相比,敲减B4GALNT1抑制了N-cadherin、Snail、Vimentin和基质金属蛋白酶9(matrix metallopreteinase 9,MMP9)的表达(均P<0.01)。结论:B4GALNT1在骨肉瘤组织及细胞系中表达上调;敲减B4GALNT1抑制了骨肉瘤的恶性表型;B4GALNT1可能作为一个癌基因在骨肉瘤细胞增殖和转移中发挥重要作用。

Objective:Osteosarcoma is the most common malignant bone tumor in children and adolescents,characterized by a high potential for proliferation and metastasis.Patients with osteosarcoma who have distant metastases generally have a poor prognosis.Challenges in treatment include incomplete resection of tumor and chemotherapy resistance,with no effective cure currently available.Recent studies suggest thatβ-1,4-N-acetyl-galactosaminyltransferase 1(B4GALNT1)plays a role in the progression of various malignant tumors.However,the function of B4GALNT1 in osteosarcoma cells has not been reported.This study aims to investigate the expression of B4GALNT1 in osteosarcoma tissues compared to normal tissues and to explore its effects on the proliferation,migration,and invasion of osteosarcoma cells,thereby providing new theoretical foundations and directions for the treatment of osteosarcoma patients.Methods:Tumor tissues and corresponding normal tissue samples were collected from 16 osteosarcoma patients who underwent tumor resection at the Second Xiangya Hospital of Central South University.The patients’ages ranged from 8 to 17 years(median age 12 years).The expression of B4GALNT1 mRNA in osteosarcoma tissues,corresponding normal tissues,3 osteosarcoma cell lines(MG63,Saos-2,and U2OS),and human fetal osteoblastic cells(hFOB)was detected using real-time reverse transcription PCR(real-time RT-PCR).The effects of B4GALNT1 knockdown on the proliferation of osteosarcoma cells Saos-2 and U2OS were analyzed using cell counting kit-8(CCK-8)assays and colony formation assays.The effects of B4GALNT1 knockdown on the migration and invasion abilities of Saos-2 and U2OS cells were evaluated using Transwell migration and invasion assays.Western blotting analysis was performed to assess the impact of B4GALNT1 knockdown on the expression of epithelial-mesenchymal transition(EMT)and invasion-related proteins in Saos-2 and U2OS cells.Results:Real-time RT-PCR results showed that B4GALNT1 mRNA expression levels were significantly higher in osteosarcoma tissues and the 3 osteosarcoma cell lines compared to normal tissues and hFOB cells(all P<0.01).CCK-8 and colony formation assays indicated that B4GALNT1 knockdown significantly reduced the proliferation rate of osteosarcoma cells compared to the control group(all P<0.05).Transwell migration and invasion assays demonstrated that B4GALNT1 knockdown significantly decreased the number of migrating and invading osteosarcoma cells(all P<0.01).Western blotting analysis revealed that B4GALNT1 knockdown inhibited the expression of N-cadherin,Snail,Vimentin,and matrix metalloproteinase 9(MMP9)compared to the control group(all P<0.01).Conclusion:B4GALNT1 is upregulated in osteosarcoma tissues and cell lines,and its knockdown suppresses the malignant phenotype of osteosarcoma cells.B4GALNT1 may function as an oncogene in the proliferation and metastasis of osteosarcoma cells.