1. SK4 channels modulate Ca2+ signalling and cell cycle progression in murine breast cancer
- Author
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Sandra Beer-Hammer, Andrea Barnert, Corinna J. Mohr, Pierre Koch, Werner Schroth, Benjamin Stegen, Peter Ruth, Robert Lukowski, Wing-Yee Lo, Stephan M. Huber, Hiltrud Brauch, Reiner Hoppe, Friederike A. Steudel, Hoang Y. Nguyen, and Marc Steinle
- Subjects
0301 basic medicine ,Male ,Cancer Research ,medicine.medical_specialty ,Time Factors ,polyoma virus middle T‐antigen (PyMT) ,Intracellular Space ,Endogeny ,Ca2+‐activated K+ channels of intermediate conductance (SK4, KCa3.1, IK, KCNN4) ,Kaplan-Meier Estimate ,Biology ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Breast cancer ,breast cancer ,In vivo ,Internal medicine ,Cell Line, Tumor ,Genetics ,medicine ,Animals ,Epidermal growth factor receptor ,Calcium Signaling ,Research Articles ,Cell Proliferation ,Oncogene ,Cell growth ,Cell Cycle ,Cancer ,Mammary Neoplasms, Experimental ,General Medicine ,medicine.disease ,Intermediate-Conductance Calcium-Activated Potassium Channels ,mouse mammary tumour virus (MMTV) ,Transplantation ,Disease Models, Animal ,030104 developmental biology ,Endocrinology ,Oncology ,Mammary Tumor Virus, Mouse ,030220 oncology & carcinogenesis ,Cancer research ,biology.protein ,Molecular Medicine ,Calcium ,Female ,epidermal growth factor receptor 2 (Her2/cNeu) ,Research Article - Abstract
Oncogenic signalling via Ca2+-activated K+ channels of intermediate conductance (SK4, also known as KCa3.1 or IK) has been implicated in different cancer entities including breast cancer. Yet, the role of endogenous SK4 channels for tumourigenesis is unclear. Herein, we generated SK4-negative tumours by crossing SK4-deficient (SK4 KO) mice to the polyoma middle T-antigen (PyMT) and epidermal growth factor receptor 2 (cNeu) breast cancer models in which oncogene expression is driven by the retroviral promotor MMTV. Survival parameters and tumour progression were studied in cancer-prone SK4 KO in comparison to wildtype (WT) mice and in a syngeneic orthotopic mouse model following transplantation of SK4-negative or WT tumour cells. SK4 activity was modulated by genetic or pharmacological means using the SK4 inhibitor TRAM-34 in order to establish the role of breast tumour SK4 for cell growth, electrophysiological signalling, and [Ca2+]i oscillations. Ablation of SK4 and TRAM-34 treatment reduced the SK4-generated current fraction, growth factor-dependent Ca2+ entry, cell cycle progression and the proliferation rate of MMTV-PyMT tumour cells. In vivo, PyMT oncogene-driven tumourigenesis was only marginally affected by the global lack of SK4, whereas tumour progression was significantly delayed after orthotopic implantation of MMTV-PyMT SK4-KO breast tumour cells. However, overall survival and progression-free survival time in the MMTV-cNeu mouse model were significantly extended in the absence of SK4. Collectively, our data from murine breast cancer models indicate that SK4 activity is crucial for cell cycle control. Thus, the modulation of this channel should be further investigated towards a potential improvement of existing anti-tumour strategies in human breast cancer.
- Published
- 2017