ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression
Young-Ho Ahn, … , Elsa R. Flores, Jonathan M. Kurie
Young-Ho Ahn, … , Elsa R. Flores, Jonathan M. Kurie
Published August 1, 2012
Citation Information: J Clin Invest. 2012;122(9):3170-3183. https://doi.org/10.1172/JCI63608.
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ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression

Abstract

Metastatic cancer is extremely difficult to treat, and the presence of metastases greatly reduces a cancer patient’s likelihood of long-term survival. The ZEB1 transcriptional repressor promotes metastasis through downregulation of microRNAs (miRs) that are strong inducers of epithelial differentiation and inhibitors of stem cell factors. Given that each miR can target multiple genes with diverse functions, we posited that the prometastatic network controlled by ZEB1 extends beyond these processes. We tested this hypothesis using a mouse model of human lung adenocarcinoma metastasis driven by ZEB1, human lung carcinoma cells, and human breast carcinoma cells. Transcriptional profiling studies revealed that ZEB1 controls the expression of numerous oncogenic and tumor-suppressive miRs, including miR-34a. Ectopic expression of miR-34a decreased tumor cell invasion and metastasis, inhibited the formation of promigratory cytoskeletal structures, suppressed activation of the RHO GTPase family, and regulated a gene expression signature enriched in cytoskeletal functions and predictive of outcome in human lung adenocarcinomas. We identified several miR-34a target genes, including Arhgap1, which encodes a RHO GTPase activating protein that was required for tumor cell invasion. These findings demonstrate that ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression and provide a compelling rationale to develop miR-34a as a therapeutic agent in lung cancer patients.

Authors

Young-Ho Ahn, Don L. Gibbons, Deepavali Chakravarti, Chad J. Creighton, Zain H. Rizvi, Henry P. Adams, Alexander Pertsemlidis, Philip A. Gregory, Josephine A. Wright, Gregory J. Goodall, Elsa R. Flores, Jonathan M. Kurie

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Figure 4

miR-34a regulates multiple biological properties of tumor cells.

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miR-34a regulates multiple biological properties of tumor cells. (A–D) 3...
(A–D) 344SQ_miR-34a cells and 344SQ_vector cells were cultured in the presence or absence of doxycycline (Dox). (A) Q-PCR analysis of miR-34a levels. (B) Cell numbers in monolayer. Migrating (C) and invading (D) cells in Boyden chambers were photographed and counted. Scale bars: 100 μm. (E) Primary tumor weight and total lung metastases from flank tumors in syngeneic mice (mean ± SD, n = 5). P values were determined by 2-tailed Student’s t test. (F) MDA-MB-231 cells were transiently transfected with a random sequence miR precursor molecule control or with pre–miR-34a precursor. Shown are Q-PCR analysis of miR-34a levels, expressed relative to control transfectants (set at 1.0), and migration and invasion assays in Boyden chambers. (G and H) Q-PCR analysis of epithelial (Cdh1 and Scrib) and mesenchymal (Cdh2 and Vim) markers and their transcriptional regulators (Zeb1, Zeb2, Snai1, Snai2, and Twist1) in 344SQ_vector and 344SQ_miR-34a cells (G) and in MDA-MB-231 cells transiently transfected with pre-miR control or pre–miR-34a precursor (H). Results are expressed relative to control transfectants (set at 1.0). Data are mean ± SD (n = 3). *P < 0.01. (I) Kaplan-Meier analysis of 3 independent cohorts of lung cancer patients (33–35), comparing the differences in risk between tumors with high (>0) or low (<0) scores (36), reflecting the presence or absence, respectively, of overlap with the murine miR-34a signature. P values from log-rank (differences between arms) and univariate Cox (gene signature score as a continuous variable) tests are shown.