WTX通过ARHGDIA/CDC42/PAKs调控细胞骨架稳定性抑制结直肠癌肝转移机制研究

Liver metastases is an important death reason for colorectal cancer, but the mechanism is still unclear. Our research found that WTX silence played an vital role in liver metastasis of colorectal cancer. According to 2D electrophoresis and mass spectrometry analysis, we found that WTX could affect the expression of ARHGDIA and multiple cytoskeleton proteins. ARHGDIA is one of the important Rho GTP inhibitor and cytoskeleton regulators. Combining with the preliminary experimental verification, we predict that WTX might inhibit liver metastasis through ARHGDIA induced CDC42/PAKs pathway to maintain cytoskeleton stability in colorectal cancer. To verify this suppose, we prepare to study as follow: ① In vitro analyzing the interaction between WTX and ARHGDIA/CDC42/PAKs pathways. And exploring the function of WTX/ARHGDIA/CDC42/PAKs pathways in liver metastases of colorectal cancer. ② Using colorectal in situ and liver metastases tumor validate the function and mechanism of WTX and related signaling pathway in colorectal cancer development. ③ WTX knockout mouse model (Lgr5cre;WTX-/-) will be used to verify the action and mechanism of WTX and WTX/ARHGDIA/CDC42/PAKs pathways in liver metastases of colorectal cancer in vivo. Screening pathway inhibitors to find new targeted drug for anti-hepatic metastases of colorectal cancer. The project will clarify the mechanisms of WTX inhibiting liver metastasis of colorectal cancer, and discover new therapeutic targets for inhibiting liver metastases of colorectal cancer.

肝转移是结直肠癌致死重要原因。我们研究发现WTX在抑制结直肠癌肝转移过程中发挥重要作用，但是机制不明。2D电泳并质谱分析，发现WTX过表达影响ARHGDIA和多个细胞骨架蛋白表达。而ARHGDIA是细胞骨架调控重要分子，结合预实验验证，我们预测WTX可能通过ARHGDIA影响CDC42/PAK2/JNK通路活性，调控细胞骨架稳定性抑制结直肠癌细胞肝转移。本研究拟深入研究：①细胞水平逐层分析WTX与ARHGDIA/CDC42/PAK2通路相互作用关系及对结直肠癌肝转移的影响；②结直肠癌原位及肝转移裸鼠模型验证WTX改变对上述信号通路的调控作用及机理；③WTX结直肠敲除鼠模型进一步验证WTX缺失对结直肠癌肝转移影响及机制，并筛选通路相关抑制剂，寻找抑制结直肠癌肝转移新方法。该项目的完成，将明确WTX在抑制结直肠癌转移过程中的分子机制，为抑制结直肠癌肝转移和挖掘新的治疗靶点发挥重要作用。

X染色体上的Wilms肿瘤基因（WTX）是Wilms肿瘤的一个假定的抑癌基因，但其在其他肿瘤中的表达和功能尚不清楚。结直肠癌（CRC）是美国女性癌症相关死亡的第三大原因，也是男性癌症相关死亡的第二大原因。我们证明，在结直肠癌中WTX经常丢失，这与细胞增殖、肿瘤侵袭和转移高度相关。从机制上讲，WTX丢失破坏了RhoGDIα和CDC42之间的相互作用，失去了与RhoGDIα的结合，并触发CDC42及其下游级联的激活，促进了CRC的发展和肝转移。Mir-20a/Mir-106a的异常上调被认为是导致体内和体外结直肠癌中WTX缺失的原因。这些研究确定了mir-20a/mir-106a介导的WTX丢失如何调控CRC进展和转移的机制，并为预防CRC进展提供了一个潜在的治疗靶点。