Elevated transcription and glycosylation of B3GNT5 promotes breast cancer aggressiveness.
Elevated transcription and glycosylation of B3GNT5 promotes breast cancer aggressiveness.
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DOI：
10.1186/s13046-022-02375-5
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发表时间：
2022-05-07
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基底样乳腺癌（BLBC）因其侵袭性生物学特性且无有效的靶向药物而成为最具侵袭性的乳腺癌亚型。然而，其攻击行为背后的机制仍然知之甚少。 β1,3-N-乙酰氨基葡萄糖转移酶 V (B3GNT5) 过度表达专门发生在 BLBC 中。在这里，我们研究了 B3GBT5 促进 BLBC 侵袭性的可能分子机制。通过集落形成、乳腺球形成、细胞增殖测定、流式细胞术和蛋白质印迹测试B3GNT5对乳腺癌细胞的潜在影响。通过蛋白质印迹、实时定量 PCR 和流式细胞术测定 B3GNT5 的糖基化模式和相关功能。通过体外和体内肿瘤发生模型评估 B3GNT5 表达对 BLBC 的影响。在这项研究中，我们发现 B3GNT5 拷贝数扩增和 B3GNT5 启动子的低甲基化导致了 B3GNT5 在 BLBC 中的过表达。 B3GNT5 的敲除强烈降低了 SSEA-1 的表面表达，并阻碍了 BLBC 细胞的癌症干细胞 (CSC) 样特性。我们的结果还表明，B3GNT5 蛋白高度 N-糖基化，这对其蛋白稳定性至关重要。临床上，B3GNT5表达升高与恶性程度高、肿瘤体积大、生存率低相关，提示乳腺癌患者预后不良。我们的工作揭示了 B3GNT5 过表达和糖基化与 BLBC 中 CSC 特性增强的关键关联。这些发现表明 B3GNT5 有潜力成为 BLBC 的预后标志物和治疗靶点。在线版本包含可在 10.1186/s13046-022-02375-5 获取的补充材料。
Basal-like breast cancer (BLBC) is the most aggressive subtype of breast cancer because of its aggressive biological characteristics and no effective targeted agents. However, the mechanism underlying its aggressive behavior remain poorly understood. β1,3-N-acetylglucosaminyltransferase V (B3GNT5) overexpression occurs specifically in BLBC. Here, we studied the possible molecular mechanisms of B3GBT5 promoting the aggressiveness of BLBC. The potential effects of B3GNT5 on breast cancer cells were tested by colony formation, mammosphere formation, cell proliferation assay, flow cytometry and Western blotting. The glycosylation patterns of B3GNT5 and associated functions were determined by Western blotting, quantitative real-time PCR and flow cytometry. The effect of B3GNT5 expression on BLBC was assessed by in vitro and in vivo tumorigenesis model. In this study, we showed that B3GNT5 copy number amplification and hypomethylation of B3GNT5 promoter contributed to the overexpression of B3GNT5 in BLBC. Knockout of B3GNT5 strongly reduced surface expression of SSEA-1 and impeded cancer stem cell (CSC)-like properties of BLBC cells. Our results also showed that B3GNT5 protein was heavily N-glycosylated, which is critical for its protein stabilization. Clinically, elevated expression of B3GNT5 was correlated with high grade, large tumor size and poor survival, indicating poor prognosis of breast cancer patients. Our work uncovers the critical association of B3GNT5 overexpression and glycosylation with enhanced CSCs properties in BLBC. These findings suggest that B3GNT5 has the potential to become a prognostic marker and therapeutic target for BLBC. The online version contains supplementary material available at 10.1186/s13046-022-02375-5.