Epithelial-to-mesenchymal transition drives a pro-metastatic Golgi compaction process through scaffolding protein PAQR11
Xiaochao Tan, … , Yanzhuang Wang, Jonathan M. Kurie
Xiaochao Tan, … , Yanzhuang Wang, Jonathan M. Kurie
Published November 21, 2016
Citation Information: J Clin Invest. 2017;127(1):117-131. https://doi.org/10.1172/JCI88736.
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Research Article Cell biology Oncology

Epithelial-to-mesenchymal transition drives a pro-metastatic Golgi compaction process through scaffolding protein PAQR11

Abstract

Tumor cells gain metastatic capacity through a Golgi phosphoprotein 3–dependent (GOLPH3-dependent) Golgi membrane dispersal process that drives the budding and transport of secretory vesicles. Whether Golgi dispersal underlies the pro-metastatic vesicular trafficking that is associated with epithelial-to-mesenchymal transition (EMT) remains unclear. Here, we have shown that, rather than causing Golgi dispersal, EMT led to the formation of compact Golgi organelles with improved ribbon linking and cisternal stacking. Ectopic expression of the EMT-activating transcription factor ZEB1 stimulated Golgi compaction and relieved microRNA-mediated repression of the Golgi scaffolding protein PAQR11. Depletion of PAQR11 dispersed Golgi organelles and impaired anterograde vesicle transport to the plasma membrane as well as retrograde vesicle tethering to the Golgi. The N-terminal scaffolding domain of PAQR11 was associated with key regulators of Golgi compaction and vesicle transport in pull-down assays and was required to reconstitute Golgi compaction in PAQR11-deficient tumor cells. Finally, high PAQR11 levels were correlated with EMT and shorter survival in human cancers, and PAQR11 was found to be essential for tumor cell migration and metastasis in EMT-driven lung adenocarcinoma models. We conclude that EMT initiates a PAQR11-mediated Golgi compaction process that drives metastasis.

Authors

Xiaochao Tan, Priyam Banerjee, Hou-Fu Guo, Stephen Ireland, Daniela Pankova, Young-ho Ahn, Irodotos Michail Nikolaidis, Xin Liu, Yanbin Zhao, Yongming Xue, Alan R. Burns, Jonathon Roybal, Don L. Gibbons, Tomasz Zal, Chad J. Creighton, Daniel Ungar, Yanzhuang Wang, Jonathan M. Kurie

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Figure 1

EMT leads to the formation of compact Golgi with improved ribbon linking and cisternal stacking.

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EMT leads to the formation of compact Golgi with improved ribbon linking...
(A) The scatter plot shows Golgi organelle areas normalized to nuclear areas in epithelial and mesenchymal KP cells. Each dot represents Golgi organelle area in a single cell. (B) Confocal micrographs of Golgi (GM130, green) and nuclei (DAPI, magenta) in representative epithelial (393P) and mesenchymal (344SQ) KP cells. A compact Golgi structure is indicated (arrow). Scale bars: 3 μm. (C) Confocal micrographs of a flank tumor formed by subcutaneous injection of 344SQ cells into a syngeneic, immunocompetent mouse. Nuclei were counterstained with DAPI (blue) and merged with GM130 (green) and vimentin (red) in an overlaid image (right); the magnified images show compact and dispersed Golgi morphologies in areas of high and low vimentin, respectively. Scale bars: 30 μm. The scatter plot to the right of the images shows normalized fluorescence intensities of cells (dots) measured radially inward from the tumor periphery. The curve fits for vimentin, GM130, and DAPI (red, green, and blue lines, respectively) were obtained from nonlinear regression using a 1-phase exponential decay equation. (D) Pseudocolored images of the Golgi enzyme GalNAcT in 344SQ cells and 393P cells at indicated time points during FRAP assays. The bleached regions of interest are indicated by arrowheads, and intensity levels are indicated by a lookup table (LUT) bar. Scale bars: 3 μm. (E) The scatter plot shows the intensity recovery profile (%) after photobleaching (n = 20 cells per group). (F) Electron micrographs of representative cisternal stacks (arrows) in 393P cells (left) and 344SQ cells (right). Scale bar: 1 μm. Bar graphs show the mean numbers of cisternae per stack (left) and cisternal lengths (right). n ≥ 10 cells per group. P values indicated (2-tailed Student’s t test). Results were replicated (n ≥ 2 experiments).