Depletion of mitochondrial protease OMA1 alters proliferative properties and promotes metastatic growth of breast cancer cells

Authors

Amita Daverey, University of Nebraska–LincolnFollow
Roman M. Levytskyy, University of Nebraska - Lincoln
Kimberly M. Stanke, University of Nebraska - LincolnFollow
Martonio Ponte Viana, University of Nebraska - LincolnFollow
Samantha Swenson, University of Nebraska - LincolnFollow
Stephen Hayward, University of Nebraska - Lincoln
Madhusudhanan Narasimhan, Texas Tech University Health Sciences Center
Oleh Khalimonchuk, University of Nebraska-LincolnFollow
Srivatsan Kidambi, University of Nebraska - LincolnFollow

ORCID IDs

Oleh Khalimonchuk

Srivatsan Kidambi

Date of this Version

2019

Document Type

Article

Citation

Scientific Reports | (2019) 9:14746

Comments

© The Author(s) 2019

Open access

https://doi.org/10.1038/s41598-019-49327-2

Abstract

Metastatic competence of cancer cells is influenced by many factors including metabolic alterations and changes in mitochondrial biogenesis and protein homeostasis. While it is generally accepted that mitochondria play important roles in tumorigenesis, the respective molecular events that regulate aberrant cancer cell proliferation remain to be clarified. Therefore, understanding the mechanisms underlying the role of mitochondria in cancer progression has potential implications in the development of new therapeutic strategies. We show that low expression of mitochondrial quality control protease OMA1 correlates with poor overall survival in breast cancer patients. Silencing OMA1 in vitro in patientderived metastatic breast cancer cells isolated from the metastatic pleural effusion and atypical ductal hyperplasia mammary tumor specimens (21MT-1 and 21PT) enhances the formation of filopodia, increases cell proliferation (Ki67 expression), and induces epithelial-mesenchymal transition (EMT). Mechanistically, loss of OMA1 results in alterations in the mitochondrial protein homeostasis, as reflected by enhanced expression of canonic mitochondrial unfolded protein response genes. These changes significantly increase migratory properties in metastatic breast cancer cells, indicating that OMA1 plays a critical role in suppressing metastatic competence of breast tumors. Interestingly, these results were not observed in OMA1-depleted non-tumorigenic MCF10A mammary epithelial cells. This newly identified reduced activity/levels of OMA1 provides insights into the mechanisms leading to breast cancer development, promoting malignant progression of cancer cells and unfavorable clinical outcomes, which may represent possible prognostic markers and therapeutic targets for breast cancer treatment.