MicroRNA-21 in pancreatic ductal adenocarcinoma tumor-associated fibroblasts promotes metastasis

• Published in: PloS one 2013-08, Vol.8 (8), p.e71978-e71978
• Main Authors: Kadera, Brian E, Li, Luyi, Toste, Paul A, Wu, Nanping, Adams, Curtis, Dawson, David W, Donahue, Timothy R
• Format: Article
• Language: English
• Subjects: Actin; Adenocarcinoma; Adenocarcinoma - genetics; Adenocarcinoma - metabolism; Adenocarcinoma - pathology; Aged; Alcohol; Animals; Base Sequence; Biology; Cancer; Carcinoma, Pancreatic Ductal - genetics; Carcinoma, Pancreatic Ductal - metabolism; Carcinoma, Pancreatic Ductal - pathology; Cell Line; Cell Line, Tumor; Cell Movement - genetics; Cell survival; Chemoresistance; Correlation; DNA microarrays; Female; Fibroblasts; Fibroblasts - metabolism; Fibroblasts - pathology; Gene expression; Gene Expression Regulation, Neoplastic; Genes; Genetic aspects; Health aspects; Humans; Immunofluorescence; In Situ Hybridization; Kaplan-Meier Estimate; Kinases; Laboratories; Lung cancer; Lymph; Lymph nodes; Lymphatic Metastasis; Male; Medical prognosis; Medicine; Mesenchyme; Metastases; Metastasis; Mice; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; MicroRNA; MicroRNAs; MicroRNAs - genetics; Middle Aged; miRNA; Muscles; Pancreas; Pancreatic cancer; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleic acid; RNA; Rodents; Smooth muscle; Stroma; Surgery; Survival; Tumor cells; Tumor Cells, Cultured; Tumors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0071978

Pancreatic ductal adenocarcinoma (PDAC) is projected to rise to the second leading cause of U.S. cancer-related deaths by 2020. Novel therapeutic targets are desperately needed. MicroRNAs (miRs) are small noncoding RNAs that function by suppressing gene expression and are dysregulated in cancer. miR-21 is overexpressed in PDAC tumor cells (TC) and is associated with decreased survival, chemoresistance and invasion. Dysregulation of miR regulatory networks in PDAC tumor-associated fibroblasts (TAFs) have not been previously described. In this study, we show that miR-21 expression in TAFs promotes TC invasion. In-situ hybridization for miR-21 was performed on the 153 PDAC patient UCLA tissue microarray and 23 patient-matched lymph node metastases. Stromal and TC histoscores were correlated with clinicopathologic parameters by univariate and multivariate Cox regression. miR-21 positive cells were further characterized by immunofluorescence for mesenchymal/epithelial markers. For in vitro studies, TAFs were isolated from freshly resected human PDAC tumors by the outgrowth method. miR-21 was overexpressed/inhibited in fibroblasts and then co-cultured with GFP-MiaPaCa TCs to assess TC invasion in modified Boyden chambers. miR-21 was upregulated in TAFs of 78% of tumors, and high miR-21 significantly correlated with decreased overall survival (P = 0.04). Stromal miR-21 expression was also significantly associated with lymph node invasion (P = 0.004), suggesting that it is driving TC spread. Co-immunofluorescence revealed that miR-21 colocalized with peritumoral fibroblasts expressing α-smooth muscle actin. Moreover, expression of miR-21 in primary TAFs correlated with miR-21 in TAFs from patient-matched LN metastases; evidence that PDAC tumor cells induce TAFs to express miR-21. miR-21 expression in TAFs and TCs promotes invasion of TCs and is inhibited with anti-miR-21. miR-21 expression in PDAC TAFs is associated with decreased overall survival and promotes TC invasion. Anti-miR-21 may represent a novel therapeutic strategy for dual targeting of both tumor and stroma in PDAC.