miR-155, identified as anti-metastatic by global miRNA profiling of a metastasis model, inhibits cancer cell extravasation and colonization in vivo and causes significant signaling alterations

TY - JOUR

T1 - miR-155, identified as anti-metastatic by global miRNA profiling of a metastasis model, inhibits cancer cell extravasation and colonization in vivo and causes significant signaling alterations

AU - Thomsen, Karina G

AU - Terp, Mikkel G

AU - Lund, Rikke R

AU - Søkilde, Rolf

AU - Elias, Daniel

AU - Bak, Martin

AU - Litman, Thomas

AU - Beck, Hans C

AU - Lyng, Maria B

AU - Ditzel, Henrik J

PY - 2015/10/6

Y1 - 2015/10/6

N2 - To gain insight into miRNA regulation in metastasis formation, we used a metastasis cell line model that allows investigation of extravasation and colonization of circulating cancer cells to lungs in mice. Using global miRNA profiling, 28 miRNAs were found to exhibit significantly altered expression between isogenic metastasizing and non-metastasizing cancer cells, with miR-155 being the most differentially expressed. Highly metastatic mesenchymal-like CL16 cancer cells showed very low miR-155 expression, and miR-155 overexpression in these cells lead to significantly decreased tumor burden in lungs when injected intravenously in immunodeficient mice. Our experiments addressing the underlying mechanism of the altered tumor burden revealed that miR-155-overexpressing CL16 cells were less invasive than CL16 control cells in vitro, while miR-155 overexpression had no effect on cancer cell proliferation or apoptosis in established lung tumors. To identify proteins regulated by miR-155 and thus delineate its function in our cell model, we compared the proteome of xenograft tumors derived from miR-155-overexpressing CL16 cells and CL16 control cells using mass spectrometry-based proteomics. >4,000 proteins were identified, of which 92 were consistently differentially expressed. Network analysis revealed that the altered proteins were associated with cellular functions such as movement, growth and survival as well as cell-to-cell signaling and interaction. Downregulation of the three metastasis-associated proteins ALDH1A1, PIR and PDCD4 in miR-155-overexpressing tumors was validated by immunohistochemistry. Our results demonstrate that miR-155 inhibits the ability of cancer cells to extravasate and/or colonize at distant organs and brings additional insight into the complexity of miR-155 regulation in metastatic seeding.

AB - To gain insight into miRNA regulation in metastasis formation, we used a metastasis cell line model that allows investigation of extravasation and colonization of circulating cancer cells to lungs in mice. Using global miRNA profiling, 28 miRNAs were found to exhibit significantly altered expression between isogenic metastasizing and non-metastasizing cancer cells, with miR-155 being the most differentially expressed. Highly metastatic mesenchymal-like CL16 cancer cells showed very low miR-155 expression, and miR-155 overexpression in these cells lead to significantly decreased tumor burden in lungs when injected intravenously in immunodeficient mice. Our experiments addressing the underlying mechanism of the altered tumor burden revealed that miR-155-overexpressing CL16 cells were less invasive than CL16 control cells in vitro, while miR-155 overexpression had no effect on cancer cell proliferation or apoptosis in established lung tumors. To identify proteins regulated by miR-155 and thus delineate its function in our cell model, we compared the proteome of xenograft tumors derived from miR-155-overexpressing CL16 cells and CL16 control cells using mass spectrometry-based proteomics. >4,000 proteins were identified, of which 92 were consistently differentially expressed. Network analysis revealed that the altered proteins were associated with cellular functions such as movement, growth and survival as well as cell-to-cell signaling and interaction. Downregulation of the three metastasis-associated proteins ALDH1A1, PIR and PDCD4 in miR-155-overexpressing tumors was validated by immunohistochemistry. Our results demonstrate that miR-155 inhibits the ability of cancer cells to extravasate and/or colonize at distant organs and brings additional insight into the complexity of miR-155 regulation in metastatic seeding.

KW - Aldehyde Dehydrogenase/genetics

KW - Animals

KW - Apoptosis Regulatory Proteins/genetics

KW - Biomarkers, Tumor/genetics

KW - Carrier Proteins/genetics

KW - Cell Line, Tumor

KW - Cell Movement

KW - Cell Proliferation

KW - Female

KW - Gene Expression Profiling/methods

KW - Gene Expression Regulation, Neoplastic

KW - Genetic Predisposition to Disease

KW - Humans

KW - Immunohistochemistry

KW - Lung Neoplasms/genetics

KW - Mass Spectrometry

KW - Mice

KW - Mice, SCID

KW - MicroRNAs/genetics

KW - Nuclear Proteins/genetics

KW - Oligonucleotide Array Sequence Analysis

KW - Phenotype

KW - Protein Interaction Maps

KW - Proteomics/methods

KW - RNA-Binding Proteins/genetics

KW - Signal Transduction

KW - Time Factors

KW - Transfection

U2 - 10.18632/oncotarget.4942

DO - 10.18632/oncotarget.4942

M3 - Journal article

C2 - 26317550

SN - 1949-2553

VL - 6

SP - 29224

EP - 29239

JO - OncoTarget

JF - OncoTarget

IS - 30

ER -