Dataset Information

A UBE2O-AMPKα2 axis that promotes tumor initiation and progression offers opportunities for therapy

ABSTRACT: UBE2O is localized in the 17q25 locus, which is known to be amplified in human cancers, but its role in tumorigenesis remains undefined. Here we show that Ube2o deletion in MMTV-PyVT or TRAMP mice profoundly impairs tumor initiation, growth and metastasis, while switching off the metabolic reprogramming of tumor cells. Mechanistically, UBE2O specifically targets AMPKα2 for ubiquitination and degradation, and thereby promotes activation of the mTOR-HIF1α pathway. Notably, inactivation of AMPKα2, but not AMPKα1, abrogates the tumor attenuation caused by UBE2O-loss, while treatment with rapamycin or inhibition of HIF1α ablates UBE2O-dependent tumor biology. Finally, pharmacological blockade of UBE2O inhibits tumorigenesis through the restoration of AMPKα2, suggesting the UBE2O-AMPKα2 axis as a potential cancer therapeutic target.

ORGANISM(S): Mus musculus

PROVIDER: GSE92919 | GEO | 2017/09/08

SECONDARY ACCESSION(S): PRJNA358834

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Background: More than 90% mortality of triple negative breast cancer (TNBC) patients are attributed to cancer metastasis with organotropism. Lung is the frequent site of TNBC metastasis. However, the precise mechanism of lung-specific metastasis of TNBC, particularly the driving factors, is not well understood. Methods: RNA sequencing was performed to identify patterns of gene expression associated with lung metastatic behavior using 4T1-LM3, 231-LM3 and their parental cells (4T1-P, 231-P). Expressions of RGCC, encoding the completion 32 protein response protein, were detected in TNBC cells and tissues by qRT-PCR, western blotting and IHC. Kinase activity assay were performed to evaluated PLK1 kinase activity and the amount of phosphorylated AMP-activated protein kinase α2 (AMPKα2). RGCC-mediated metabolism was determined by UHPLC system. Oxidative phosphorylation was evaluated by JC-1 staining and oxygen consumption rate (OCR) assay. Fatty acid oxidation assay, NADPH and ROS was applied to measure the status of RGCC-mediated fatty acid oxidation. The chemical sensitivity of cells was evaluated by CCK8 assay. Results: RGCC is aberrantly upregulated in pulmonary metastatic cells. High level of RGCC is significantly related with lung metastasis rather than other organ metastases. RGCC can effectively promote the kinase activity of PLK1, and activated PLK1 phosphorylates AMPKα2 to facilitate TNBC lung metastasis. Mechanistically, Survival and colonization of TNBC cells in the lungs by upregulating oxidative phosphorylation of mitochondria to obtain more energy and promoting fatty acid oxidation to produce abundant NADPH and sustains redox homeostasis, thus prevents excessive accumulation of potentially detrimental ROS in metastatic tumor cells, ultimately establishing metastases. Importantly, targeting RGCC in combination with paclitaxel/carboplatin effectively suppresses pulmonary metastases of TNBC in a mouse model. Conclusions: The enhanced RGCC is closely associated with lung-specific metastasis of TNBC. RGCC leads to activation of AMPKα2 and downstream signaling through RGCC-driven PLK1 activity to facilitate TNBC lung metastasis, which may determine a potential value of RGCC-driven OXPHOS and fatty acid oxidation as an important therapeutic target.

Project description:Purpose: Mutations in STK11 (LKB1) occur in 17% of lung adenocarcinoma (LUAD) and drive a suppressive (cold) tumor immune microenvironment (TME) and resistance to immunotherapy. The mechanisms underpin the establishment and maintenance of a cold TME in LKB1 mutant LUAD remain poorly understood and the identification of downstream effectors is critical to inform therapeutic strategies to invigorate antitumor immunity. In this study, we investigated the association between inactivation of AMPK, one of the downstream substrates of LKB1, and immune evasion in human LUAD as well as the causal role of AMPK on TME in genetically engineered mouse model (GEMM) of LUAD. Experimental Design: We modeled AMPK inactivation in vivo using GEMM by deleting both AMPKα1 (Prkaa1) and AMPKα2 (Prkaa2) in KrasG12D-driven LUAD (KAA). Furthermore, we investigated the impact of AMPK inactivation on immune cell infiltration and global gene-expression programs of murine LUAD. Gene expression signature from AMPK-deficient murine LUAD was further compared to that of Lkb1 deficient murineLUAD as well as human LUAD with either LKB1 mutation or attenuated AMPK phosphorylation. Results: Inactivation of both AMPKα1 and AMPKα2 accelerates KrasG12D-driven LUAD. AMPK-deficient tumors are characterized with reduced infiltration of CD8+/CD4+ T cells and gene signatures associated with compromised immune microenvironment, which resembles LKB1-deficient murine and human LUAD (KL) as well as LKB1-wildtype LUAD with reduced AMPK phosphorylation. Attenuation of the MHC Class 1 component ß2 microglobulin (ß2M) was identified as a shared feature in KL and KAA murine LUAD as well as in human LUAD with either LKB1 mutations or reduced AMPK phosphorylation. Furthermore, reactivation of AMPK by expression of constitutive active form of AMPKα1 leads to restoration of ß2M level in LKB1 mutant LUAD cells. Conclusions: The results identify attenuation of the LKB1 substrate AMPK as an important mechanism for decreased MHC Class 1 expression and immune evasion in LKB1 mutant LUAD. Translational relevance: LKB1 loss-of-function mutations rank as the third most common genetic alterations found in lung adenocarcinoma and associated with immune evasion. In the current study, on the basis of GEMM of LUAD we established the causal relationship between inactivation of the LKB1 substrate AMPK and immune evasion. Furthermore we find that the status of AMPK phosphorylation is more sensitive than LKB1 mutation in predicting impaired tumor immune microenvironment and likely also for the resistance to immunotherapy. The results also suggest that restoration of AMPK activity could increase the number of patients benefiting from immunotherapy.

Dataset Information

A UBE2O-AMPKα2 axis that promotes tumor initiation and progression offers opportunities for therapy

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure