AMPK activators suppress breast cancer cell growth by inhibiting DVL3-facilitated Wnt/beta-catenin signaling pathway activity
MOLECULAR MEDICINE REPORTS
Authors: Zou, Yu-Feng; Xie, Chun-Wei; Yang, Shi-Xin; Xiong, Jian-Ping
Abstract
Adenosine monophosphate-activated protein kinase (AMPK) is a principal regulator of metabolism and the conservation of energy in cells, and protects them from exposure to various stressors. AMPK activators may exhibit therapeutic potential as suppressors of cell growth; however, the molecular mechanism underlying this phenomenon in various cancer cells remains to be fully elucidated. The present study investigated the effects of AMPK activators on breast cancer cell growth and specified the underlying molecular mechanism. In the present study, the AMPK activator metformin impaired breast cancer cell growth by reducing dishevelled segment polarity protein 3 (DVL3) and beta-catenin levels. Western blotting and immunohistochemistry demonstrated that DVL3 was recurrently upregulated in breast cancer cells that were not treated with metformin, and was significantly associated with enhanced levels of beta-catenin, c-Myc and cyclin D1. Overexpression of DVL3 resulted in upregulation of beta-catenin and amplification of breast cancer cell growth, which confirmed that Wnt/beta-catenin activation via DVL3 is associated with breast cancer oncogenesis. To elucidate the underlying mechanism of these effects, the present study verified that metformin resulted in a downregulation of DVL3 and beta-catenin in a dose-dependent manner, and induced phosphorylation of AMPK. Compound C is an AMPK inhibitor, which when administered alongside metformin, significantly abolished the effects of metformin on the reduction of DVL3 and activation of the phosphorylation of AMPK. Notably, the effects of metformin on the mRNA expression levels of DVL3 remain to be fully elucidated; however, a possible interaction with DVL3 at the post-transcriptional level was observed. It has previously been suggested that the molecular mechanism underlying AMPK activator-induced suppression of breast cancer cell growth involves an interaction with, and impairment of, DVL3 proteins. The results of the present study are of future clinical importance and advocate the use of metformin as a potential therapeutic agent against breast cancer.
Investigating Radiotherapy Response in a Novel Syngeneic Model of Prostate Cancer
CANCERS
Authors: Haughey, Charles M.; Mukherjee, Debayan; Steele, Rebecca E.; Popple, Amy; Dura-Perez, Lara; Pickard, Adam; Patel, Mehjabin; Jain, Suneil; Mullan, Paul B.; Williams, Rich; Oliveira, Pedro; Buckley, Niamh E.; Honeychurch, Jamie; McDade, Simon S.; Illidge, Timothy; Mills, Ian G.; Eddie, Sharon L.
Abstract
Simple Summary Pre-clinical models are required to develop new therapeutics to improve patient care. In the prostate cancer field, significant progress has been made in the development of in vivo models but with a predominant focus on transgenics, which are time and cost prohibitive. Conversely, other available models do not closely resemble patient disease and tumour immune microenvironment. In this study, a new graft-based model is described, using a cell-line derived from a transgenic: the DVL3 model. Grafts using the DVL3 cells retain the pathological and immunological features of localized clinical disease, whilst genetically the model is sustained by poor prognosis drivers of disease progression. Irradiating tumours post-engraftment leads to remodeling of the tumour immune microenvironment and increased expression of genes associated with nucleic acid sensing pathways and the type I interferon response. This paper establishes this model as resource for the pre-clinical characterization of new prostate cancer therapies and biological responses to treatment. The prostate cancer (PCa) field lacks clinically relevant, syngeneic mouse models which retain the tumour microenvironment observed in PCa patients. This study establishes a cell line from prostate tumour tissue derived from the Pten(-/-)/trp53(-/-) mouse, termed DVL3 which when subcutaneously implanted in immunocompetent C57BL/6 mice, forms tumours with distinct glandular morphology, strong cytokeratin 8 and androgen receptor expression, recapitulating high-risk localised human PCa. Compared to the commonly used TRAMP C1 model, generated with SV40 large T-antigen, DVL3 tumours are immunologically cold, with a lower proportion of CD8+ T-cells, and high proportion of immunosuppressive myeloid derived suppressor cells (MDSCs), thus resembling high-risk PCa. Furthermore, DVL3 tumours are responsive to fractionated RT, a standard treatment for localised and metastatic PCa, compared to the TRAMP C1 model. RNA-sequencing of irradiated DVL3 tumours identified upregulation of type-1 interferon and STING pathways, as well as transcripts associated with MDSCs. Upregulation of STING expression in tumour epithelium and the recruitment of MDSCs following irradiation was confirmed by immunohistochemistry. The DVL3 syngeneic model represents substantial progress in preclinical PCa modelling, displaying pathological, micro-environmental and treatment responses observed in molecular high-risk disease. Our study supports using this model for development and validation of treatments targeting PCa, especially novel immune therapeutic agents.