| First Author | Miao ZF | Year | 2021 |
| Journal | Gastroenterology | Volume | 160 |
| Issue | 1 | Pages | 260-271.e10 |
| PubMed ID | 32956680 | Mgi Jnum | J:302100 |
| Mgi Id | MGI:6507668 | Doi | 10.1053/j.gastro.2020.09.016 |
| Citation | Miao ZF, et al. (2021) DDIT4 Licenses Only Healthy Cells to Proliferate During Injury-induced Metaplasia. Gastroenterology 160(1):260-271.e10 |
| abstractText | BACKGROUND AND AIMS: In stomach, metaplasia can arise from differentiated chief cells that become mitotic via paligenosis, a stepwise program. In paligenosis, mitosis initiation requires reactivation of the cellular energy hub mTORC1 after initial mTORC1 suppression by DNA damage induced transcript 4 (DDIT4 aka REDD1). Here, we use DDIT4-deficient mice and human cells to study how metaplasia increases tumorigenesis risk. METHODS: A tissue microarray of human gastric tissue specimens was analyzed by immunohistochemistry for DDIT4. C57BL/6 mice were administered combinations of intraperitoneal injections of high-dose tamoxifen (TAM) to induce spasmolytic polypeptide-expressing metaplasia (SPEM) and rapamycin to block mTORC1 activity, and N-methyl-N-nitrosourea (MNU) in drinking water to induce spontaneous gastric tumors. Stomachs were analyzed for proliferation, DNA damage, and tumor formation. CRISPR/Cas9-generated DDIT4(-/-) and control human gastric cells were analyzed for growth in vitro and in xenografts with and without 5-fluorouracil (5-FU) treatment. RESULTS: DDIT4 was expressed in normal gastric chief cells in mice and humans and decreased as chief cells became metaplastic. Paligenotic Ddit4(-/-) chief cells maintained constitutively high mTORC1, causing increased mitosis of metaplastic cells despite DNA damage. Lower DDIT4 expression correlated with longer survival of patients with gastric cancer. 5-FU-treated DDIT4(-/-) human gastric epithelial cells had significantly increased cells entering mitosis despite DNA damage and increased proliferation in vitro and in xenografts. MNU-treated Ddit4(-/-) mice had increased spontaneous tumorigenesis after multiple rounds of paligenosis induced by TAM. CONCLUSIONS: During injury-induced metaplastic proliferation, failure of licensing mTORC1 reactivation correlates with increased proliferation of cells harboring DNA damage, as well as increased tumor formation and growth in mice and humans. |
