CDC20 Knockdown and Acidic Microenvironment Collaboratively Promote Tumorigenesis through Inhibiting Autophagy and Apoptosis.

The reconstitution of the tumorigenesis process would shed light on the tumor development study and further drug selection strategies. To construct a tumorigenesis model and explore potential mechanism is of great importance. In our study, we observed that CDC20-knockdown cells cultured in acidic environment exhibited chromosomal instability and better survival ability. The tumorigenic metabolism transformation was confirmed through the increase of the extracellular acidification rate (ECAR) and decrease of the oxygen consumption rate (OCR) in CDC20-knockdown cells. After a long-term culture for 3-4 months, CDC20-knockdown cells in acidic medium showed a strong tumor formation ability by subcutaneous injection into mice that is similar to that of tumor cells. Meanwhile, transcriptome analysis of cells from different stages showed that stage D cells almost resembled the phenotype of immortal cancer cells. The oncogene accumulation laid a firm foundation in the development of the tumorigenesis process by suppressing autophagy and p53-induced apoptosis. Several autophage- and apoptosis-related genes showed inhibition during this tumorigenesis process. In summary, chromosomal instability induced by CDC20 knockdown and acidic microenvironment could collaboratively promote cell tumorigenesis through the downregulation of autophagy and apoptosis.