Mutant p53–associated myosin-X upregulation promotes breast cancer invasion and metastasis
Antti Arjonen, … , Heikki Joensuu, Johanna Ivaska
Antti Arjonen, … , Heikki Joensuu, Johanna Ivaska
Published February 3, 2014
Citation Information: J Clin Invest. 2014;124(3):1069-1082. https://doi.org/10.1172/JCI67280.
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Research Article Oncology

Mutant p53–associated myosin-X upregulation promotes breast cancer invasion and metastasis

Abstract

Mutations of the tumor suppressor TP53 are present in many forms of human cancer and are associated with increased tumor cell invasion and metastasis. Several mechanisms have been identified for promoting dissemination of cancer cells with TP53 mutations, including increased targeting of integrins to the plasma membrane. Here, we demonstrate a role for the filopodia-inducing motor protein Myosin-X (Myo10) in mutant p53–driven cancer invasion. Analysis of gene expression profiles from 2 breast cancer data sets revealed that MYO10 was highly expressed in aggressive cancer subtypes. Myo10 was required for breast cancer cell invasion and dissemination in multiple cancer cell lines and murine models of cancer metastasis. Evaluation of a Myo10 mutant without the integrin-binding domain revealed that the ability of Myo10 to transport β1 integrins to the filopodia tip is required for invasion. Introduction of mutant p53 promoted Myo10 expression in cancer cells and pancreatic ductal adenocarcinoma in mice, whereas suppression of endogenous mutant p53 attenuated Myo10 levels and cell invasion. In clinical breast carcinomas, Myo10 was predominantly expressed at the invasive edges and correlated with the presence of TP53 mutations and poor prognosis. These data indicate that Myo10 upregulation in mutant p53–driven cancers is necessary for invasion and that plasma-membrane protrusions, such as filopodia, may serve as specialized metastatic engines.

Authors

Antti Arjonen, Riina Kaukonen, Elina Mattila, Pegah Rouhi, Gunilla Högnäs, Harri Sihto, Bryan W. Miller, Jennifer P. Morton, Elmar Bucher, Pekka Taimen, Reetta Virtakoivu, Yihai Cao, Owen J. Sansom, Heikki Joensuu, Johanna Ivaska

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Figure 7

Myo10 is necessary for mutant p53–driven invasion.

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Myo10 is necessary for mutant p53–driven invasion. (A) Western blot of M...
(A) Western blot of MCF10A and MDA-MB-231 cells treated 16 hours with DMSO or MEK inhibitor (UO126, 10 μM). NT, non-treated. (B)TaqMan qRT-PCR of MYO10 and EGR1 mRNA levels in MDA-MB-231 cells silenced with 2 different p53 targeting oligos. n = 2 (sip53_13); n = 4 (sip53_3). (C) Western blot and TaqMan qRT-PCR showing Myo10 expression upon silencing of EGR1 for 48 hours. (D) ChIP analysis of mutant p53 or EGR1 binding to MYO10 promoter by PCR using Myo10 promoter–specific primers. IgG antibody was used as negative control. (E) Matrigel invasion of shMyo10 cells upon silencing of TP53 (areas of invasion, n = 10, ×20 objective). (F) Invasion of murine PDAC cells transfected with siMyo10 or siArpc2 (Arp2/3 component, positive control) into Matrigel-overlaid wounds. (G) MCF-7 cells were transfected as indicated, and invasion was analyzed as in E. (H) Invasion of p53-silenced MDA-MB-231 cells transfected as indicated (percentage of invaded/all GFP-positive cells; n = 9–14; ×20 objective. (I) Model of mutant p53–driven, integrin-dependent invasion. (a) Mutant p53 induces Myo10 that contributes to mutant p53–driven invasion by transporting integrin to filopodia tips. (b) Mutant p53 increases integrin and EGFR recycling to the plasma membrane (19) providing integrins to be transported to filopodia tips by Myo10. (c) Mutant p53 drives Myo10 by increasing EGR1 transcription directly and via MAPK/ERK signaling. (d) Increased integrin-EGFR recycling elevates PIP3 levels via PI3K/Akt pathway (19) and activates Myo10 (48). Mean ± SEM and Mann-Whitney test P values are shown.