MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer
Mick D. Edmonds, Kelli L. Boyd, Tamara Moyo, Ramkrishna Mitra, Robert Duszynski, Maria Pia Arrate, Xi Chen, Zhongming Zhao, Timothy S. Blackwell, Thomas Andl, Christine M. Eischen
Mick D. Edmonds, Kelli L. Boyd, Tamara Moyo, Ramkrishna Mitra, Robert Duszynski, Maria Pia Arrate, Xi Chen, Zhongming Zhao, Timothy S. Blackwell, Thomas Andl, Christine M. Eischen
View: Text | PDF
Research Article Oncology

MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer

Abstract

MicroRNA (miR) are important regulators of gene expression, and aberrant miR expression has been linked to oncogenesis; however, little is understood about their contribution to lung tumorigenesis. Here, we determined that miR-31 is overexpressed in human lung adenocarcinoma and this overexpression independently correlates with decreased patient survival. We developed a transgenic mouse model that allows for lung-specific expression of miR-31 to test the oncogenic potential of miR-31 in the lung. Using this model, we observed that miR-31 induction results in lung hyperplasia, followed by adenoma formation and later adenocarcinoma development. Moreover, induced expression of miR-31 in mice cooperated with mutant KRAS to accelerate lung tumorigenesis. We determined that miR-31 regulates lung epithelial cell growth and identified 6 negative regulators of RAS/MAPK signaling as direct targets of miR-31. Our study distinguishes miR-31 as a driver of lung tumorigenesis that promotes mutant KRAS-mediated oncogenesis and reveals that miR-31 directly targets and reduces expression of negative regulators of RAS/MAPK signaling.

Authors

Mick D. Edmonds, Kelli L. Boyd, Tamara Moyo, Ramkrishna Mitra, Robert Duszynski, Maria Pia Arrate, Xi Chen, Zhongming Zhao, Timothy S. Blackwell, Thomas Andl, Christine M. Eischen

×

Figure 7

miR-31 directly targets multiple negative regulators of the RAS/MAPK pathway.

Options: View larger image (or click on image) Download as PowerPoint
miR-31 directly targets multiple negative regulators of the RAS/MAPK pat...
(A) Shared putative miR-31 target mRNA identified from 3 prediction algorithms are listed. Asterisks denote mRNA that were manually aligned and determined to have a putative miR-31–binding region. Schematic of the RAS/MAPK signaling pathway. (B and C) qRT-PCR (performed in triplicate) for putative miR-31 target mRNA of (B) Beas-2B cells transfected with miR-31 mimic or RNA control or (C) A549 cells transfected with miR-31 inhibitor or inhibitor control. Values are normalized to β-actin levels. *P < 0.04, t tests. Data are representative of 3 independent experiments. (D) Beas-2B cells infected with miR-31–encoded (31) lentivirus or an empty lentivirus (–) and A549 cells transfected with miR-31 inhibitor (31 inh) or inhibitor control (–) were Western blotted. Densitometry results are shown in Supplemental Figure 7C. The data presented are representative of at least 2 independent experiments, and the data for both Beas-2B and A549 cells were from 3 separate experiments run on different gels. (E) 293T cells were transfected with luciferase vectors encoding all or a region of the 3′-UTR from each gene indicated (two parts of SPRED1 3′-UTR) and miR-31 mimic, miR-17-5p mimic, or RNA control. Luciferase assays were performed (performed in triplicate); expression is relative to β-galactosidase activity. *P < 0.03, t tests. Data are representative of 4 independent experiments. (F) MTT assays of H1993 cells infected with a miR-31–encoded retrovirus or empty retrovirus (vector) and transfected with vectors encoding the indicated miR-31 target cDNA. Experiments are representatives of 2 independent experiments. Error bars represent SEM.