Geriatrics Department, Suqian First Hospital, No. 120, Suzhi Road, Sucheng District, Suqian, Jiangsu Province, 223899, PR China.
Prenatal Diagnosis Center, Suqian First Hospital, No. 120, Suzhi Road, Sucheng District, Suqian, Jiangsu Province, 223899, PR China.
BMC Cancer. 2021 Feb 19;21(1):180. doi: 10.1186/s12885-021-07898-2.
Aberrant activation of the Wnt/β-catenin signaling pathway is one of the most frequent abnormalities in human cancer, including colorectal cancer (CRC). Previous studies revealed pivotal functions of WNT family members in colorectal cancer, as well as their prognostic values. Nevertheless, the prognostic role and mechanisms underlying WNT7b in colorectal cancer development remains unclear.
In this study, WNT7b expression was measured by immunohistochemical staining of 100 cases of surgically resected human colorectal cancerous tissues as well as matched adjacent normal tissues constructed as tissue microarrays. In vitro studies, we attempted to substantiate the WNT7b expressional pattern previously found in immunohistochemistry staining. We used the colorectal cancer cell-line HCT116 and normal colorectal cell-line FHC for immunofluorescence staining and nuclear/cytoplasmic separated western blotting. We measured epithelial-mesenchymal transition (EMT) markers and migration capacity of HCT116 in the context of WNT7b knocked-down using short interfering RNA. Finally, clinical and prognostic values of WNT7b activation levels were examined.
WNT7b was expressed in the nucleus in adjacent normal tissues. In CRC tissues, nuclear expression of WNT7b was similar; however, membrane and cytoplasmic expression was strikingly enhanced. Consistently, in vitro analysis confirmed the same expression pattern of WNT7b. Compared with FHC cells, HCT116 cells displayed higher levels of WNT7b membrane and cytoplasmic enrichment, as well as higher migration capacity with a sensitized EMT process. Either partial knockdown of WNT7b or blockade of the Wnt/β-catenin signaling pathway reversed EMT process and inhibited the migration of HCT116 cells. Finally, elevated secretion levels of WNT7b were significantly associated with lymphatic and remote metastasis and predicted worse prognosis in the CRC cohort.
In summary, we demonstrated that the activation of WNT7b autocrine probably contributes to CRC metastasis by triggering EMT process through the Wnt/β-catenin signaling pathway. High levels of WNT7b autocrine secretion predicts poor outcome in patients with CRC. This molecule is a promising candidate for clinical CRC treatments.
Wnt/β-连环蛋白信号通路的异常激活是人类癌症（包括结直肠癌）中最常见的异常之一。先前的研究表明 WNT 家族成员在结直肠癌中的关键作用及其预后价值。然而，WNT7b 在结直肠癌发展中的预后作用和机制尚不清楚。
本研究通过免疫组织化学染色，对 100 例手术切除的人结直肠癌细胞组织及配对的组织微阵列构建的相邻正常组织进行 WNT7b 表达检测。在体外研究中，我们试图证实免疫组织化学染色中发现的 WNT7b 表达模式。我们使用结直肠癌细胞系 HCT116 和正常结直肠细胞系 FHC 进行免疫荧光染色和核/细胞质分离的 Western blot。我们使用 WNT7b 短发夹 RNA 敲低来测量 HCT116 中的上皮间质转化（EMT）标志物和迁移能力。最后，检查了 WNT7b 激活水平的临床和预后价值。
WNT7b 在相邻正常组织的核中表达。在 CRC 组织中，WNT7b 的核表达相似；然而，膜和细胞质表达明显增强。同样，体外分析证实了 WNT7b 的相同表达模式。与 FHC 细胞相比，HCT116 细胞显示出更高水平的 WNT7b 膜和细胞质富集，以及更敏感的 EMT 过程和更高的迁移能力。WNT7b 的部分敲低或阻断 Wnt/β-连环蛋白信号通路逆转了 EMT 过程并抑制了 HCT116 细胞的迁移。最后，WNT7b 的分泌水平升高与淋巴和远处转移显著相关，并预测 CRC 队列的预后不良。
总之，我们证明了 WNT7b 自分泌的激活可能通过 Wnt/β-连环蛋白信号通路触发 EMT 过程促进 CRC 转移。WNT7b 自分泌的高水平预示着 CRC 患者预后不良。该分子是 CRC 临床治疗的有前途的候选者。
