Ion channels and apoptosis in cancer

Abstract

Humans maintain a constant cell number throughout their lifespan. This equilibrium of cell number is accomplished when cell proliferation and cell death are kept balanced, achieving a steady-state cell number. Abnormalities in cell growth or cell death can lead to an overabundance of cells known as neoplasm or tumours. While the perception of cancer is often that of an uncontrollable rate of cell growth or increased proliferation, a decrease in cell death can also lead to tumour formation. Most cells when detached from their normal tissue die. However, cancer cells evade cell death, tipping the balance to an overabundance of cell number. Therefore, overcoming this resistance to cell death is a decisive factor in the treatment of cancer. Ion channels play a critical role in cancer in regards to cell proliferation, malignant angiogenesis, migration and metastasis. Additionally, ion channels are also known to be critical components of apoptosis. In this review, we discuss the modes of cell death focusing on the ability of cancer cells to evade apoptosis. Specifically, we focus on the role ion channels play in controlling and regulating life/death decisions and how they can be used to overcome resistance to apoptosis in the treatment of cancer.

Keywords: apoptosis; cancer; cell death; ion channels.

Figure 1.

Modes of cell death. Apoptosis and necrosis comprise opposite ends of a continuum of programmable and non-programmable modes of cell death. Autophagy, pyroptosis and oncosis (ischaemic cell death) represent a range of cellular demise that retain some characteristics of either apoptosis or necrosis, but define a unique mode of cell death. (Online version in colour.)