Cancer stem cells and radioresistance

Abstract

Purpose: Radiation therapy has made significant contributions to cancer treatment. However, despite continuous improvements, tumor recurrence and therapy resistance still occur in a high proportion of patients. One underlying reason for this radioresistance might be attributable to the presence of cancer stem cells (CSC). The purpose of this review is to discuss CSC-specific mechanisms that confer radiation resistance.

Conclusions: We focus our discussions on breast cancer and glioblastoma multiforme (GBM) and conclude that both CSC-intrinsic and CSC-extrinsic factors as well as adaptive responses in CSC caused by irradiation and microenvironmental changes all make contributions to CSC-mediated radioresistance. Our discussions emphasize CSC as novel therapeutic targets in order to potentiate radiotherapy efficacy.

Keywords::

• Cancer stem cells
• radiation therapy
• radiosensitivity
• radioresistance
• plasticity
• microenvironment
• hypoxia

Acknowledgements

The work in the authors’ lab was supported, in part, by grants from NIH (R01-CA155693), Department of Defense (W81XWH-13-1-0352), CPRIT (RP120380), and the MDACC Center for Cancer Epigenetics and RNA Center-Laura & John Arnold Foundation grant (D.G.T). K.R was supported in part by an NIH post-doctoral fellowship.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.