K-ras突变和肿瘤低氧环境生长是结肠癌患者化疗耐受和预后差的重要因素。我们前期筛选到Adrenomedullin (ADM)是低氧下K-ras突变型结肠癌细胞的关键下游基因,.发现ADM在K-ras突变型结肠癌组织中高表达，并促进结肠癌细胞侵袭。因此，我们推测ADM是K-ras突变型结肠癌在低氧条件下生长和侵袭的关键分泌蛋白。本课题拟系统研究低氧下PI3K/Akt/mTOR和raf/MEK/Erk等K-ras下游信号通路对结肠癌细胞低氧诱导因子（HIF-1ɑ）和ADM的分子调控机制；明确ADM低氧表达是否依赖于HIF-1ɑ，并鉴定ADM低氧反应元件；体内外试验评价shRNA干扰ADM对K-ras突变型结肠癌生长，侵袭和肿瘤血管生成的影响和分子机理。研究将阐明结肠癌低氧环境下K-ras突变对HIF-1ɑ和ADM的分子调控机制，ADM"靶向"干预有望为K-ras突变型结肠癌治疗提供新途径。

Tumor cells with mutant K-ras survival in hypoxic condition was the major cause of chemotherapy-resistant and poor prognosis in patients with colon cancer. We have previously identified Adrenomedullin(ADM) as one of key downstream gene in colon cancer cells harboring mutant K-ras, and demonstrated that ADM was highly expressed in colon cancer tissues with mutational K-ras. Exogenous administration with ADM could promote tumor cell invasion.Therefore, we proposed that ADM is the key secrected protein which contributes to the growth and invasion of K-ras mutation cells. In this proposal, we aim to determine whether the induction of HIF-1ɑ and ADM by mutant K-ras was mediated through PI3K/Akt/mTOR or MEK/Erk pathways, and the expression of ADM in hypoxia was dependent upon HIF-1ɑ. We further clone and validate the hypoxia response elements in the promoter of ADM gene.The functional studies including tumor growth, invasion and angiogenesis after siliencing expression of ADM with shRNA plasmid were evaluated in vitro and in vivo. The relationship between ADM and VEGF was evaluated to understand the key mechanisms of anti-angiogenesis by ADM in hypoxic conditions. Summarily, we aim to demonstrate the key mechanisms of the regulation of HIF-1ɑ and ADM by mutant K-ras in hypoxia in colon cancer. We proposed that the molecular target with the secreted protein-ADM could be a potential therapeutic strategy of colon cancer with mutant K-ras.