Boosting Oxidative Stress with Hydroxyethyl Starch Smart Nanomedicines to Eliminate Cancer Stem Cells

The significance of cancer stem cells (CSCs), a rare population of cells in tumor tissues, in biology and the treatment of solid malignancies has been widely appreciated for more than two decades. Due to a peculiar self-renewal capability, even one single cancer stem cell can grow into a bulk tumor mass. For this reason, CSCs have long been blamed as the major culprit of tumor initiation, tumor progression, treatment resistance, metastasis, and recurrence. Therefore, it has been postulated that targeting CSCs could provide tremendous clinical benefits for patients with solid tumors. Accumulating studies corroborated that CSCs maintained a tight regulation of redox homeostasis and that the fate of CSCs was extremely sensitive to elevated oxidative stress. Accordingly, a plethora of therapeutic drugs that can generate reactive oxygen species (ROS) have been leveraged to target CSCs. Nonetheless, few drugs or formulations that are capable of elevating oxidative stress have achieved clinical success for eliminating CSCs thus far.