Translational Control of TOP2A Influences Doxorubicin Efficacy

Abstract

The cellular abundance of topoisomerase II␣ (TOP2A) critically maintains DNA topology after replication and determines the efficacy of TOP2 inhibitors in chemotherapy. Here, we report that the RNA-binding protein HuR, commonly overexpressed in cancers, binds to the TOP2A 3-untranslated region (3UTR) and increases TOP2A translation. Reducing HuR levels triggered the recruitment of TOP2A transcripts to RNA-induced silencing complex (RISC) components and to cytoplasmic processing bodies. Using a novel MS2-tagged RNA precipitation method, we identified microRNA miR-548c-3p as a mediator of these effects and further uncovered that the interaction of miR-548c-3p with the TOP2A 3UTR repressed TOP2A translation by antagonizing the action of HuR. Lowering TOP2A by silencing HuR or by overexpressing miR-548c-3p selectively decreased DNA damage after treatment with the chemotherapeutic agent doxorubicin. In sum, HuR enhances TOP2A translation by competing with miR-548c-3p; their combined actions control TOP2A expression levels and determine the effectiveness of doxorubicin.

Transformer 2β and miR-204 regulate apoptosis through competitive binding to 3′ UTR of BCL2 mRNA

“…For instance, HuR binds to the 3′ UTR of Topoisomerase IIα mRNA and increases its translation by antagonizing the binding of miR-548-3p. 33 In contrast, HuR downregulates c-Myc expression by recruiting let-7-loaded RISC to the MYC 3′ UTR. 34 Thus, when miRNA-binding sites overlap with or present near binding sites for RNA-binding proteins, RNA-binding proteins could either compete or cooperate with miRNAs via their physical interactions.…”

Systematic Screening Identifies Dual PI3K and mTOR Inhibition as a Conserved Therapeutic Vulnerability in Osteosarcoma

“…Although not strongly powered to detect loss of function alleles involved in resistance to doxorubicin, several candidates were identified ( Fig. 2A), including siRNA, against topoisomerase 2a (Top2a), the cellular target of doxorubicin (21,22), and a number of proapoptotic genes such as Bid (Fig. 1B, Supplementary Fig.…”

Induction of VEGFA mRNA translation by CoCl2 mediated by HuR

“…5A). 28 To study this interaction in live cells, the VEGFA mRNA was tagged by adding MS2 hairpins, as described in Srikantan et al 29 We constructed plasmids pMS2-RL-3 0 UTR-I and pMS2-RL-3 0 UTR-II, derived from pSL-MS2 (24X), which expressed the Renilla luciferase (RL) coding region fused to the proximal (I) and distal (II) regions of the VEGFA 3 0 UTR, respectively, along with 24 tandem MS2 RNA hairpins; a control plasmid (pMS2-RL) expressed only the RL coding region fused to MS2 hairpins (Fig. 5B, left panels).…”