The Role of Cancer Stem Cells in Radiation Resistance

Abstract

Cancer stem cells (CSC) are a distinct subpopulation within a tumor. They are able to self-renew and differentiate and possess a high capability to repair DNA damage, exhibit low levels of reactive oxygen species (ROS), and proliferate slowly. These features render CSC resistant to various therapies, including radiation therapy (RT). Eradication of all CSC is a requirement for an effective antineoplastic treatment and is therefore of utmost importance for the patient. This makes CSC the prime targets for any therapeutic approach. Albeit clinical data is still scarce, experimental data and first clinical trials give hope that CSC-targeted treatment has the potential to improve antineoplastic therapies, especially for tumors that are known to be treatment resistant, such as glioblastoma. In this review, we will discuss CSC in the context of RT, describe known mechanisms of resistance, examine the possibilities of CSC as biomarkers, and discuss possible new treatment approaches.

OSMR controls glioma stem cell respiration and confers resistance of glioblastoma to ionizing radiation

“…OSMR controls BTSC self-renewal and confers resistance to IR. Elevated levels of ROS is shown to sensitize cancer stem cells and tumor response to IR [30][31][32] . Our results demonstrated that inhibition of OSM/OSMR signalling pathway profoundly increased ROS levels, in vitro and in vivo.…”

A Marine Collagen-Based Biomimetic Hydrogel Recapitulates Cancer Stem Cell Niche and Enhances Progression and Chemoresistance in Human Ovarian Cancer

“…Moreover, multicellular spheroids with a diameter larger than approximately 100 μm contain an internal hypoxic zone caused by the limited distribution of oxygen, nutrients, and metabolites and a necrotic core [ 59 , 60 ]. The hypoxic tumor microenvironment is considered a critical component in determining drug resistance through specific cellular signaling pathways and plays a vital role in regulating the resistance of CSCs to chemotherapy and radiotherapy [ 61 , 62 , 63 , 64 , 65 ]. These findings suggest that our MC-B hydrogel provides a suitable milieu for the growth of these OC cell spheroids, which can be applied for the development of diagnostic and therapeutic strategies for OC.…”

MicroRNAs Modulate Drug Resistance-Related Mechanisms in Hepatocellular Carcinoma

“…CSCs are defined as a small proportion of cancer cells with strong self-renewal capacity and multidirectional differentiation potential ( 81 ). Most CSCs are in the G0 phase of cell cycle and are resistant to chemotherapy and radiotherapy, leading to tumor relapse and treatment failure ( 82 , 83 ). Conventional therapies often fail because they do not completely eradicate CSCs, as this subset of cells often evades the treatment via therapy-induced EMT.…”