Registered report: the microRNA miR-34a inhibits prostate cancer stem cells and metastasis by directly repressing CD44

The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altimetric scores (Errington et al., 2014). This Registered report describes the proposed replication plan of key experiments from 'The microRNA miR-34a inhibits prostate cancer stem cells and metastasis by directly repressing CD44' by Liu and colleagues published in Nature Medicine in 2011 (Liu et al., 2011). Liu and colleagues first demonstrated that miR-34a levels were reduced in CD44+ prostate cancer cells (Figure 1B). They then showed that xenograft tumors from cells expressing exogenous miR-34a were smaller in size than control tumors (Supplemental Figure 5C). Tumors with exogenous miR-34a showed reduced levels of CD44 expression (Figure 4A), and mutation of two putative miR-34a binding sites in the CD33 3' UTR partially abrogated signal repression in a luciferase assay (Figure 4D). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published by eLife.