Loss of Activin Receptor Type 1B Accelerates Development of Intraductal Papillary Mucinous Neoplasms in Mice With Activated KRAS.
Loss of Activin Receptor Type 1B Accelerates Development of Intraductal Papillary Mucinous Neoplasms in Mice With Activated KRAS.
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DOI：
10.1053/j.gastro.2015.09.013
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发表时间：
2016-01
期刊：
影响因子：
29.4
通讯作者：
Su GH
中科院分区：
文献类型：
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作者：
Qiu W;Tang SM;Lee S;Turk AT;Sireci AN;Qiu A;Rose C;Xie C;Kitajewski J;Wen HJ;Crawford HC;Sims PA;Hruban RH;Remotti HE;Su GH
激活素是转化生长因子-β (TGFB) 家族的成员，与 TGFB 家族的其他成员一样，可能参与胰腺肿瘤的发生。人胰腺导管腺癌的 IB 型激活素 A 受体 (ACVR1B) 基因中含有体细胞突变，表明 ACVR1B 可能是胰腺肿瘤发生的抑制因子。我们特别在小鼠（Acvr1bflox/flox；Pdx1-Cre 小鼠）的胰腺中破坏了 Acvr1b，并将其与 LSL-KRASG12D 小鼠杂交，LSL-KRASG12D 小鼠表达激活形式的 KRAS 并产生自发性胰腺肿瘤。对所得 Acvr1bflox/flox;LSL-KRASG12D;Pdx1-Cre 小鼠进行监测；收集胰腺组织并通过组织学和免疫组织化学分析进行分析。我们还分析了 p16flox/flox;LSL-KrasG12D;Pdx1-Cre 小鼠和 Cre 阴性同窝小鼠（对照）。从小鼠组织和原代胰腺肿瘤细胞系中分离出基因组 DNA、总 RNA 和蛋白质，并通过逆转录酶 PCR、测序和免疫印迹分析进行分析。通过免疫组织化学分析人导管内乳头状粘液性肿瘤 (IPMN) 标本。与对照小鼠相比，小鼠胰腺中 ACVR1B 的缺失增加了胰腺上皮细胞的增殖，导致腺泡形成到导管化生，并引起局灶性炎症变化。 LSL-KRASG12D 中 Acvr1b 的破坏；与LSL-KRASG12D；Pdx1-Cre小鼠相比，Pdx1-Cre小鼠加速了胰腺IPMN的生长，但没有改变胰腺上皮内瘤变的生长。我们将激活的 NOTCH4 胞内结构域的核周定位与肿瘤细胞的顶端细胞质以及 Acvr1bflox/flox;LSL-KRASG12D;Pdx1-Cre 小鼠中 IPMN 病变的扩展相关联。 Acvr1bflox/flox;LSL-KrasG12D;Pdx1-Cre 小鼠中 IPMN 进展为胰腺导管腺癌需要编码 p16 (Cdkn2a) 的基因缺失。我们还观察到人类 IPMN 中 p16 的逐渐丢失，且等级不断增加。 ACVR1B 缺失会加速突变型 KRAS 诱导的小鼠胰腺 IPMN 的生长；这个过程似乎涉及 NOTCH4 和 p16 的丢失。 ACVR1B 抑制胰腺肿瘤发生的早期阶段；因此，激活素信号通路可能成为胰腺癌的治疗靶点。
Activin, a member of the transforming growth factor-β (TGFB) family, might be involved in pancreatic tumorigenesis, like other members of the TGFB family. Human pancreatic ductal adenocarcinomas contain somatic mutations in the activin A receptor type IB (ACVR1B) gene, indicating that ACVR1B could be a suppressor of pancreatic tumorigenesis. We disrupted Acvr1b specifically in pancreata of mice (Acvr1bflox/flox;Pdx1-Cre mice) and crossed them with LSL-KRASG12D mice, which express an activated form of KRAS and develop spontaneous pancreatic tumors. The resulting Acvr1bflox/flox;LSL-KRASG12D;Pdx1-Cre mice were monitored; pancreatic tissues were collected and analyzed by histology and immunohistochemical analyses. We also analyzed p16flox/flox;LSL-KrasG12D;Pdx1-Cre mice and Cre-negative littermates (controls). Genomic DNA, total RNA, and protein were isolated from mouse tissues and primary pancreatic tumor cell lines and analyzed by reverse transcriptase PCR, sequencing, and immunoblot analyses. Human intraductal papillary mucinous neoplasm (IPMN) specimens were analyzed by immunohistochemistry. Loss of ACVR1B from pancreata of mice increased proliferation of pancreatic epithelial cells, led to formation of acinar to ductal metaplasia, and induced focal inflammatory changes, compared with control mice. Disruption of Acvr1b in LSL-KRASG12D; Pdx1-Cre mice accelerated growth of pancreatic IPMNs, compared with LSL-KRASG12D;Pdx1-Cre mice, but did not alter growth of pancreatic intraepithelial neoplasias. We associated perinuclear localization of the activated NOTCH4 intracellular domain to the apical cytoplasm of neoplastic cells and with expansion of IPMN lesions in Acvr1bflox/flox;LSL-KRASG12D;Pdx1-Cre mice. Loss of the gene that encodes p16 (Cdkn2a) was required for progression of IPMNs to pancreatic ductal adenocarcinomas in Acvr1bflox/flox;LSL-KrasG12D;Pdx1-Cre mice. We also observed progressive loss of p16 in human IPMNs of increasing grades. Loss of ACVR1B accelerates growth of mutant KRAS-induced pancreatic IPMNs in mice; this process appears to involve NOTCH4 and loss of p16. ACVR1B suppresses early stages of pancreatic tumorigenesis; the activin signaling pathway might therefor be a therapeutic target for pancreatic cancer.