American Association for Cancer Research

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Figure S4 from Capping Protein Regulator and Myosin 1 Linker 3 Is Required for Tumor Metastasis

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posted on 2023-04-03, 17:40 authored by Huan Wang, Chao Wang, Guang Peng, Doudou Yu, Xin-Gang Cui, Ying-Hao Sun, Xiaojing Ma

Supplementary Figure 4, EGFP-mCARMI3 localizes at cortical plasma membrane as well as in cytoplasm. Related to Fig. 4. A. HEK293T cells were transfected with empty vector(MSCV-FLAG) or FLAG tag CAR-MIL3(MSCV-FLAG-CARMIL3), followed by immunoprecipitation (IP) with FLAG antibody and Western blot. B. Functional annotation of Gene Ontology (GO) by GeneMANIA with CARMIL3 potential interacting proteins listed is Table 1. C and D. Localization of exogenous EGFP tagged CARMIL3 in HEK293T (C) and 4T1 (D).


Natural Science Foundation of China

Shanghai Medical Guidance (Chinese and Western Medicine) Science and Technology

Clinical Discipline Project of Shanghai Pudong

National Natural Science Foundation of China

Program of Shanghai Academic/Technology Research Leader



Metastasis accounts for 90% of deaths caused by solid tumors, but the multitude of mechanisms underlying tumor metastasis remains poorly understood. CARMIL1 and 2 proteins are capping protein (CP) interactants and multidomain regulators of actin-based mobility. However, CARMIL3′s function has not been explored. Through bioinformatic metadata analysis, we find that high CARMIL3 expression correlates with poor survival of patients with breast and prostate cancer. Functional studies in murine and xenograft tumor models by targeted diminution of CARMIL3 expression or forced expression demonstrate that CARMIL3 is vitally important for tumor metastasis, especially for metastatic colonization. Consistent with a predominantly cell-intrinsic mode of action, CARMIL3 is also crucial for tumor cell migration and invasion in vitro. Coimmunoprecipitation coupled with mass spectrometric analyses identifies a group of CARMIL3-interacting proteins, including capping protein, that are involved in actin cytoskeletal organization, which is required for cell polarization and focal adhesion formation. Moreover, molecular pathway enrichment analysis reveals that lack of CARMIL3 leads to loss of cell adhesions and low CARMIL3 expression in breast cancer patient specimens is implicated in epithelial–mesenchymal transition. We also find that CARMIL3 sustains adherens junction between tumor cells. This is accomplished by CARMIL3 maintaining E-cadherin transcription downstream of HDACs through inhibiting ZEB2 protein level, also via protecting β-catenin from ubiquitination-mediated degradation initiated by the destruction complex. This study uncovers CARMIL3 as a novel and critical regulator of metastatic progression of cancers and suggests therapeutic potentials to target CARMIL3.

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