Sex hormones and their receptors play critical roles in the development and progression of the breast and prostate cancers. Here we report that a novel type of transfer RNA (tRNA)-derived small RNA, termed Sex HOrmone-dependent TRNA-derived RNAs (SHOT-RNAs), are specifically and abundantly expressed in estrogen receptor (ER)-positive breast cancer and androgen receptor (AR)-positive prostate cancer cell lines. SHOT-RNAs are not abundantly present in ER(-) breast cancer, AR(-) prostate cancer, or other examined cancer cell lines from other tissues. ER-dependent accumulation of SHOT-RNAs is not limited to a cell culture system, but it also occurs in luminal-type breast cancer patient tissues. SHOT-RNAs are produced from aminoacylated mature tRNAs by angiogenin-mediated anticodon cleavage, which is promoted by sex hormones and their receptors. Resultant 5'- and 3'-SHOT-RNAs, corresponding to 5'- and 3'-tRNA halves, bear a cyclic phosphate (cP) and an amino acid at the 3'-end, respectively. By devising a "cP-RNA-seq" method that is able to exclusively amplify and sequence cP-containing RNAs, we identified the complete repertoire of 5'-SHOT-RNAs. Furthermore, 5'-SHOT-RNA, but not 3'-SHOT-RNA, has significant functional involvement in cell proliferation. These results have unveiled a novel tRNA-engaged pathway in tumorigenesis of hormone-dependent cancers and implicate SHOT-RNAs as potential candidates for biomarkers and therapeutic targets.
Honda, Shozo; Loher, Phillipe; Shigematsu, Megumi; Palazzo, Juan P.; Suzuki, Ryusuke; Imoto, Issei; Rigoutsos, Isidore; and Kirino, PhD, Yohei, "Sex hormone-dependent tRNA halves enhance cell proliferation in breast and prostate cancers." (2015). Computational Medicine Center Faculty Papers. Paper 6.
This article has been peer reviewed. It is the authors' final version prior to publication in Proceedings of the National Academy of Sciences of the United States of America, Volume 112, Issue 29, July 2015, Pages E3816-E3825.
The published version is available at DOI: 10.1073/pnas.1510077112. Copyright © National Academy of Sciences