Abstract 530P
Background
BUD31 has firstly been reported to play a role in intronic splicing and messenger RNA (mRNA) maturation and control the budding and cell morphology of yeast. However, the role of BUD31 in cancers remains largely unknown. BUD31 is significantly up-regulated in tumor tissues compared with normal tissues and has been associated with survival times of patients in various types of cancers.We investigated the functions of BUD31 and the ways how it affects tumor progression by studying tumor samples and cell lines.
Methods
BUD31 was knocked down or expressed by small interfering RNAs or expression of lentiviral vectors in esophageal squamous cell carcinoma (ESCC) cells (KYSE30 and KYSE450), HeLa, and HGC27 cells, and we analyzed effects on proliferation, colony formation, migration, and invasion in vitro. Cells were grown as xenograft tumors in nude mice, and tumor volume and tumor weight were quantified. Cells were also analyzed for levels of mRNA and protein expressions. We obtained ESCC and adjacent normal esophageal tissues from 94 patients who underwent esophagectomy in China from 2010 through 2014, sequenced mRNAs, and compared levels between tumor and non-tumor tissues using the Wilcox rank-sum test. Immunoblotting assay measured total proteins in cell lines or tissue samples. We searched publicly available databases for BUD31 in human esophageal tumor and non-tumor tissues.
Results
Knockdown of BUD31 reduced proliferation of ESCC cells in vitro and xenograft tumors in mice. Cells that overexpressed BUD31 were more aggressive in migration and invasion assays. Cells that overexpressed BUD31 had increased expressions of mRNAs and proteins associated with carcinogenesis, including MCM7, and c-MYC. Overexpression of BUD31 up-regulated expression of MCM7 through intronic splicing, which in turn up-regulated expression of c-MYC and promoted cancer cell proliferation and aggressiveness. Knockdown of MCM7 reduced expression of c-MYC. Levels of MCM7 mRNA correlated with levels of BUD31 in esophageal cancer samples from patients.
Conclusions
These findings reveal important role of BUD31 in the carcinogenesis and oncogenic switch by mRNA splicing and present BUD31 as a promising therapeutic target for cancers.
Legal entity responsible for the study
National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College.
Funding
Guangdong Medical Science and Technology Research Foundation.
Disclosure
All authors have declared no conflicts of interest.