title: An anti-let-7 sponge decoys and decays endogenous let-7 functions.
abstract: The let-7 family contains 12 members, which share identical seed regions, suggesting that they may target the same mRNAs. It is essential to develop a means that can regulate the functions of all members. Using a DNA synthesis technique, we have generated an anti-let-7 sponge aiming to modulate the function of all members. We found that products of the anti-let-7 construct could bind and inactivate all members of the let-7 family, producing decoy and decay effects. To test the role of the anti-let-7 sponge, we stably expressed the anti-let-7 construct in two types of cells, the breast carcinoma cells MT-1 and the oldest and most commonly used human cervical cancer cell line, HeLa cells. We found that expression of anti-let-7 increased cell survival, invasion and adhesion, which corroborate with known functions of let-7 family members. We further identified a novel target site across all species of the let-7 family in hyaluronan synthase 2 (HAS2). HAS2 overexpression produced similar effects as the anti-let-7 sponge. Silencing HAS2 expression by siRNAs produced opposite effects to anti-let-7 on cell survival and invasion. The ability of anti-let-7 to regulate multiple members of the let-7 family allows us to observe their multiple functions using a single reagent. This approach can be applied to other family members with conserved sequences.
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Canada.
authors.forename: Xiangling
authors.initials: X
authors.lastname: Yang
authors.forename: Zina Jeyapalan
authors.initials: ZJ
authors.lastname: Rutnam
authors.forename: Chunwei
authors.initials: C
authors.lastname: Jiao
authors.forename: Duo
authors.initials: D
authors.lastname: Wei
authors.forename: Yizhen
authors.initials: Y
authors.lastname: Xie
authors.forename: Jun
authors.initials: J
authors.lastname: Du
authors.forename: Ling
authors.initials: L
authors.lastname: Zhong
authors.forename: Burton B
authors.initials: BB
authors.lastname: Yang
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D002470:Cell Survival; D005260:Female; D014453:Glucuronosyltransferase / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D000076002:Hyaluronan Synthases; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D034622:RNA Interference; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs; D034741:RNA, Small Interfering; C487931:mirnlet7 microRNA, human; D014453:Glucuronosyltransferase; C101754:HAS2 protein, human; D000076002:Hyaluronan Synthases