MiR-31 promotes mammary stem cell expansion and breast tumorigenesis by suppressing Wnt signaling antagonists
Authors: Wei Cui
Yuhua Tian
Baowei Jiao
Yue Zhang
Jianwei Shuai
Xu Feng
Yongli Song
Maksim V Plikus
Cong Lv
Liming Luan
Mingang Xu
Fengyin Li
Zhengquan Yu
Xiaole Sheng
Christopher Lengner
Thomas Andl
Shukai Yuan
Xiang Li
Fazheng Ren
Sarah E Millar
Qingyong Meng
Xing Dai
Journal: Nature Communications (2017)
Discipline: Multidisciplinary
Keywords: MicroRNA; post-transcriptional regulation; stem cell; self-renewal; tumorigenesis
Affiliations: State Key Laboratories for Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China., Department of Biochemistry and Molecular Biology, Hebei Key Laboratory of Chinese Medicine Research on Cardio-Cerebrovascular Disease, Hebei University of Chinese Medicine, Shijiazhuang, Hebei, 050200, China., Department of Biochemistry and Molecular Biology, Basic Medical College, Tianjin Medical University, Tianjin, 300070, China., Vanderbilt University Medical Center, Nashville, TN, 37232, USA., State Key Laboratory of Genetic Resources and Evolution of Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China., Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA., Department of Developmental and Cell Biology, Sue and Bill Gross Stem Cell Research, Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA., Departments of Biological Chemistry and Dermatology, School of Medicine, University of California, Irvine, CA, 92697, USA., Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA., Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA., Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA., Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK., Department of Physics and State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, Xiamen University, Xiamen, 361005, China., State Key Laboratories for Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China. .

Abstract:  MicroRNA-mediated post-transcriptional regulation plays key roles in stem cell self-renewal and tumorigenesis. However, the in vivo functions of specific microRNAs in controlling mammary stem cell (MaSC) activity and breast cancer formation remain poorly understood. Here we show that miR-31 is highly expressed in MaSC-enriched mammary basal cell population and in mammary tumors, and is regulated by NF-κB signaling. We demonstrate that miR-31 promotes mammary epithelial proliferation and MaSC expansion at the expense of differentiation in vivo. Loss of miR-31 compromises mammary tumor growth, reduces the number of cancer stem cells, as well as decreases tumor-initiating ability and metastasis to the lung, supporting its pro-oncogenic function. MiR-31 modulates multiple signaling pathways, including Prlr/Stat5, TGFβ and Wnt/β-catenin. Particularly, it activates Wnt/β-catenin signaling by directly targeting Wnt antagonists, including Dkk1. Importantly, Dkk1 overexpression partially rescues miR31-induced mammary defects. Together, these findings identify miR-31 as the key regulator of MaSC activity and breast tumorigenesis. 

Retracted: No

PubPeer comments:
 Figure 4A. A reader pointed out a concern about the flow cytometry panels and I found some more. Boxes of the same color focus attention on areas that look more similar than expected. ![file] , 
 Thank you very much for your interest in our work! I just noticed this comment. In Figure 4a, we do show the representative images for FACS on mammary epithelial cells in control (TRE-miR-31 and K5-rtTA) and DTG mice, suggesting that miR-31 overexpression increases the number of mammary stem cells. For some reason, some mistakes were shown in the R3 area. Honestly I did not figure out what happen. However, firstly I want to mention that the Figure 4a is the representative images for Figure 4b and that the quantification results are shown in Figure 4b. We do have three replicates for the result. Indeed, another biological replicate result was shown in Figure 8i in this paper. Secondly, I want to point to that the R3 area is not important for our result, they are usually dead cells or cell pieces, and the R8 population is the mammary stem cells that important for our result. Thirdly, we have utilized complete knockout and cKO mice to demonstrate that loss of miR-31 reduced the number of mammary stem cells. Thus, I hope that you agree with us that this mistake does not affect any our conclusion. In addition, we have attached another replicate result for K5-rtTA and DTG mice in this comment. , 
 ![file] Here is the attachment for another replicate. , 
 Dear Dr. Zhengquan Yu, Thank you for your reply. *  *For some reason, some mistakes were shown in the R3 area. Honestly I did not figure out what happen.* - this is a bit of a disappointing answer. Could you please check the original raw data? What type of mistakes happened here? I cannot imagine how an unintentional mistake could explain these repetitive areas. Maybe you can provide some more explanation, please? *  *I want to point to that the R3 area is not important for our result* - this is irrelevant. There appears to be intentional image duplication in the image, therefore casting serious doubt about not just this quadrant or this image, but all figures and other data in this paper. Any figure shown in your paper IS the data, so everything is important. *  *Thirdly, we have utilized complete knockout and cKO mice to demonstrate that loss of miR-31 reduced the number of mammary stem cells.* - is also irrelevant. I am asking for what happened in Figure 4A. * The image you posted in #3 is very low resolution. Could you post something closer to 1 MB (maximum size allowed here). * Posting another flow cytometry image does not take away my concerns about Figure 4A. , 
 Dear Dr. Bik, Thank you very much for your quick response! I will take serious investigation on this mistake and then give a detailed response. , 
 Any updates, Dr. Yu? , 
 Author Correction, October 2020: https: www.nature.com articles s41467-020-19103-2  *The original version of this Article contained an error in Fig. 4. In the original Fig. 4a (shown below), different quadrants within the same FACS plot and between different plots contained similar unexplained groups of data points. The raw data of the original figure are not available as they were deleted at the FACS facility where the analysis was performed. The experiments have several original replicates, for which raw data are available. The experiments have also been repeated for added robustness and the new version of Fig. 4a is shown below. This has been corrected in both the PDF and HTML versions of the Article.* , 
 Could the authors please provide a good explanation for the duplicated areas in the FACS plots? I have only seen these types of duplications as the result of post-instrumental measurement alterations, and I find the authors explanation in combination with the deletion of these original files not very satisfactory. In addition, could the authors please check Supplemental Figure 1J? The two panels appear to look identical. ![file] ,