Nanomedicine in cancer stem cell therapy

It is now well established that most of the tumors are heterogeneous in nature that comprise a population of cancer stem cells (CSCs) and differentiated cancer cells. Like normal stem cells, CSCs have also self-renewal, proliferation, and differentiation capacities that are responsible for the development of drug resistance and relapse. Therefore, targeting CSCs is essential for the elimination of tumor recurrence condition. Although several anti-CSC therapeutics have been used in clinics, they are found to have limited efficacy due to poor solubility, lesser stability, and short circulation time in the blood. Therefore, tools in nanomedicines are being used to tackle these limitations. Recently, nanodrug carriers have been used to target CSCs and somewhat eliminate drug resistance by targeting CSC metabolism, inhibiting drug transporters, disturbing CSC survival pathways, etc. Even with these progress, the challenges for targeting CSCs by nanomedicines still remain and open up plenty of space for further development and improvement in synthesizing drug carriers with higher efficacy. In this chapter, we summarize about CSCs and their biological characterization toward resistance, then discuss several anti-CSC therapeutic approaches based on nanomedicines in the current state of research and development, and finally overview their future directions.