Abstract The mortality rate due to metastasis in cancer is as high as 90%. The underlying mechanisms have been studied, however, the process of metastasis is complicated, current therapies still cannot inhibit metastasis efficiently. In recent years, studies have mentioned that extracellular vesicles play an important role in cancer cell metastasis and tumor microenvironment. Extracellular vesicles can be divided into microvesicles, apoptotic bodies and exosomes, which can carry different substances into the tumor microenvironment. Especially exosomes, whose diameter is around 30-160nm, can carry DNA, RNA, miRNA, membrane proteins, lipids and other intracellular molecules into the cell through endocytosis for regulation. The process of metastasis and the drug resistance were also been demonstrated can be regulated by exosomes. At present, the physiological functions of exosomes are not clear. HT29 colon cancer cells previously discovered in our laboratory can have different responses to dasatinib treatment, and cells can be isolated to dasatinib selected cells(DSTS) and resistant cells(DSTR). In this study, the role of exosome upon dasatinib treatment in HT29 cell is investigated. In the experiment, exosomes from HT29, DSTS, and DSTR were isolated by ExoQuick-TC. Transmission electron microscope was used to observe the difference in exosome size. Exosomes from different cells were treated in HT29 cells, and differences at the protein and mRNA levels were observed using western blot and reverse transcription-polymerase chain reaction(RT-PCR). In my results, the diameter of exosomes in DSTS cells was smaller than that in DSTR and HT29 cells. The protein expression levels of Cavoelin-1 and Clathrin in HT29 were also increased in the treatment of exosome that from three types of cells. In addition, the DSTR derived-exosomes can induce the expression of pFAK and Clathrin mRNA in HT29 cells. The preliminary results suggest that DSTR derived-exosomes may affect cell migration. This study provides the clues that through understanding exosomes that secreted from different cells, cancer diagnosis and treatment can be conducted according to their characteristics, so as to reduce the possibility of cell metastasis precisely. Citation Format: Hui Min Koo, Yi-Wen Lu, Xiang-Ling Hou, Wei-Ting Chao. Investigates the role of exosomes in dasatinib treated HT29 colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6973.