Collagen facilitates the colorectal cancer sternness and metastasis through an integrin/PI3K/AKT/Snail signaling pathway

Purpose: Dynamic remodeling of the extracellular matrix (ECM) around tumor cells is crucial for the tumor progressions. However, the mechanism is not well defined. Here, we aimed to reveal the underlying mechanism of ECM induced metastasis and provide innovative strategy to suppress the distant metastasis induced by ECM. Materials and Methods: IHC was used to detect the expression of target proteins. H&E staining was used to evaluate the growth of tumor in vivo. Using wound healing and transwell assay, we examined the ability of cell to metastasis. We employed IF and Western blot to detect the expression of target proteins. And qRT-PCR was used to examine the target genes in mRNA level. We also applied flow cytometry to examine the percent of CD133(+) cell population. Results: Herein, we observed elevated expression of type I collagen in colorectal cancer tissues from patients with high metastasis. Additionally, colorectal cancer cells cultured on 2D collagen reveal obviously enhanced capability of metastasis and tumorigenesis both in vitro and in vivo. We demonstrated that the activation of PI3K/AKT signal induced by integrin alpha 2 beta 1 resulted in the enhanced metastatic capability and stemness of colorectal cancer cells. Moreover, we found that Snail worked as the downstream of PI3K/AKT signaling, resulting in the intensive invasion and metastasis of colorectal cancer. Blocking the pathway by applying E7820 successfully reversed the type I collagen induced distant metastasis in colorectal cancer. Conclusion: Combining E7820 and chemotherapeutic agents to block the integrin alpha 2 beta 1/PI3K/AKT/Snail signaling pathway revealed dramatic enhanced tumor suppression and provided an innovative approach for clinical colorectal cancer treatment.