CRISPR z-bo 2020-09-18 355

　　Intestinal epithelium is the fastest cell regeneration tissue in the human body, which can quickly regenerate and repair the intestinal mucosa, but this ability also has certain risks. It is known that cryptographic stem cells in the intestine can trigger tumorigenesis and play an important role in tumor cell differentiation, proliferation and apoptosis.

　　The medium containing stem cell nestin (WNT, R-spondin, epithelial growth factor EGF) can be used to cultivate mouse and human intestinal stem cells for a longer period of time to produce genetically and phenotypically stable epithelial organoids. I will. Professor Hans Clevers, dean of the Dutch Academy of Arts and Royal Academy of Sciences, and a member of the National Academy of Sciences, led a research team to establish colon cancer (CRC) organoids using CRISPR/Cas9 technology.

　　The results of this research were published in the journal Nature this week. Colorectal cancer usually develops slowly from adenomas. This means that the development of colorectal cancer may be a process of constantly acquiring gene mutations. Researchers have applied CRISPR/Cas9 technology to human intestinal stem cells cultured in vitro to introduce the four most common colorectal cancer gene mutations (APC, P53, KRAS and SMAD4). They screened for mutant cells by removing growth factors from the culture medium. According to research, cells with quadruple mutations can proliferate without stem cell nestin and can tolerate the tumor suppressor Nutlin-3. After these cells are transplanted into mice, they grow into aggressive tumors. It is worth noting that APC and P53 mutations are sufficient to cause widespread chromosomal abnormalities (heterogeneity), which are characteristic of tumorigenesis.

　　Not long ago, the research team used a similar method to introduce mutations through the CRISPR system to establish a colorectal cancer model. Clevers pointed out that when they screened for mutant cells and all sgRNAs for mutation hot spots, his own colorectal cancer development model could more closely reflect tumorigenesis in vivo.