Abstract 4334: Epigenetic reprogramming of tissue-specific transcription promotes metastasis

Metastasis is the cause of death for 90% of cancer patients, but little is known about how cancer cells adapt to and colonize new tissue environments. Colorectal cancer (CRC) is the third most common cancer and the fourth most common cancer cause of death globally. Here, we investigated how metastatic cancer cells, such as CRC cells, with original-tissue specificity adapt to the environment of a distant tissue, like liver. By analyzing transcriptome data of multiple cohorts of clinical samples and primary/metastatic cell lines, we found metastatic CRC cells lose their colon-specific gene transcription program and gain a liver-specific gene transcription program as they metastasize in the liver. The elevated expression of a number of liver-specific genes was confirmed in human liver metastatic tumors by immunohistochemistry. Through epigenomic profiling, we revealed this transcription reprogramming is driven by a reshaped epigenetic landscape of both typical and super-enhancers, and chemical inhibition of enhancer activity disrupts the ability of cells to execute this altered transcription program and consequently inhibits metastasis. Further we identified liver-specific transcription factors, FOXA2 and HNF1A, bind to the gained enhancers in liver metastatic cells and activate the expression of liver-specific genes. We also found both FOXA2 and HNF1A are highly expressed in human liver metastatic tumors compared to primary CRC tumors. Loss of function of FOXA2 or HNF1A inhibits liver-specific transcription and impairs the ability of metastatic CRC cells to adapt to liver. Consistently, the gain of function of HNF1A activated liver-specific transcription and enhanced CRC liver metastasis. Our findings indicate the direct contribution of a reprogrammed tissue-specific transcription program, which is induced by reshaped epigenetic landscape as well as distant-tissue-specific transcription factors, to the adaption and colonization of metastatic CRC cells to a distal organ. Notably, in addition to CRC liver metastasis, this tissue-specific transcription reprogramming is also observed in other multiple distant organs and/or cancer types. In summary, our data suggest that epigenetically reprogrammed tissue-specific transcription promotes metastasis and might have implications for targeted anti-metastasis therapies. Citation Format: Shuaishuai Teng, Yang Li, Ming Yang, Rui Qi, Qianyu Wang, Zhi Lu, Dong Wang. Epigenetic reprogramming of tissue-specific transcription promotes metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4334.