METHODS: Muc6 knockout (Muc6-/-) mice and Muc6-dsRED mice were newly generated. Tff1Cre, Golph3-/-, R26-Golgi-mCherry, Hes1flox/flox, Cosmcflox/flox, and A4gnt-/- mice were also used. Histology, DNA and RNA, proteins, and sugar chains were analyzed by whole-exon DNA sequence, RNA sequence, immunohistochemistry, lectin-binding assays, and liquid chromatography-mass spectrometry analysis. Gastric organoids and cell lines were used for in vitro assays and xenograft experiments.
RESULTS: Deletion of Muc6 in mice spontaneously causes pan-gastritis and invasive gastric cancers. Muc6-deficient tumor growth was dependent on mitogen-activated protein kinase activation, mediated by Golgi stress-induced up-regulation of Golgi phosphoprotein 3. Glycomic profiling revealed aberrant expression of mannose-rich N-linked glycans in gastric tumors, detected with banana lectin in association with lack of MUC6 expression. We identified a precursor of clusterin as a binding partner of mannose glycans. Mitogen-activated protein kinase activation, Golgi stress responses, and aberrant mannose expression are found in separate Cosmc- and A4gnt-deficient mouse models that lack normal O-glycosylation. Banana lectin-drug conjugates proved an effective treatment for mannose-rich murine and human gastric cancer.
CONCLUSIONS: We propose that Golgi stress responses and aberrant glycans are important drivers of and promising new therapeutic targets for gastric cancer.
方法:新产生Muc6敲除(Muc6-/-)小鼠和Muc6-dsRED小鼠。Tff1Cre,Golph3-/-,R26-高尔基-mCherry,Hes1flox/flox,Cosmcflox/flox,还使用A4gnt-/-小鼠。组织学,DNA和RNA,蛋白质,通过整个外显子DNA序列分析糖链,RNA序列,免疫组织化学,凝集素结合测定,和LC-MS分析。胃类器官和细胞系用于体外测定和异种移植实验。
结果:小鼠中Muc6的缺失会自发导致泛胃炎和侵袭性胃癌。Muc6缺陷的肿瘤生长依赖于MAPK激活,由高尔基体应激诱导的GOLPH3上调介导。糖组学分析揭示了富含甘露糖的N-连接聚糖在胃肿瘤中的异常表达,检测到香蕉凝集素与缺乏MUC6表达有关。我们鉴定了簇蛋白的前体作为甘露糖聚糖的结合配偶体。MAPK激活,高尔基应激反应,在缺乏正常O-糖基化的单独的Cosmc和A4gnt缺陷小鼠模型中发现了异常的甘露糖表达。香蕉凝集素-药物缀合物被证明是富含甘露糖的鼠和人胃癌的有效治疗方法。
结论:我们认为高尔基应激反应和异常聚糖是重要的驱动因素,和有希望的胃癌新的治疗靶点。