miR-210 Regulates ISCU Figure 5. ISCU suppression is associated to miR-210 over-expression and relapse-free survival in breast cancer and HNSCC. A, miR- 210 qPCR expression (DDCT) plotted as a function of ISCU mRNA expression (Illumina arrays) in the Oxford breast cancer series (left), and, relapse free survival for samples with high ISCU and low ISCU split by median in the Oxford breast cancer series (right). B, mRNA expression of the transcript hosting the miR-210 precursor plotted as a function of ISCU mRNA expression measure by Affymetrix U133b and U133a respectively in the Uppsala breast cancer series (left), and relapse free survival for samples with high ISCU and low ISCU split by median in the Uppsala breast cancer series (right). C, miR-210 qPCR expression (DDCT) plotted as a function of ISCU mRNA expression (Affymetrix arrays) in the Oxford-Manchester HNSCC cancer series where ISCU was initially found to be associated to hypoxia (left), and relapse free survival for samples with high ISCU and low ISCU split by median value in the Chung et al. HNSCC series (right). doi:10.1371/journal.pone.0010345.g005 Discussion Our studies clearly show miR-210 regulates the expression of ISCU RNA and protein using the mimic in normoxia in cancer cell lines. ISCU mRNA and protein were suppressed under hypoxia and this effect was significantly reversed by anti-210. The incomplete reversal implies other mechanisms are also involved in ISCU downregulation and it is well recognised that RNA translation is reduced by hypoxia via the unfolded protein response [29]. A decrease in ISCU would impair the ability of cells to generate Fe-S clusters and would subsequently impact on the activity of enzymes that require these co-factor moieties. We showed that PLoS ONE | www.plosone.org 7 April 2010 | Volume 5 | Issue 4 | e10345