Targeting Cancer Stem Cells: Implications in Health and Disease

Cancer is a serious global health concern as it accounts for about 9.6 million deaths worldwide. Despite striking breakthroughs made in understanding, prevention, and treatment of cancer, the mortality rate is still high and no permanent cure has been found. The major concern is the lack of effective therapies against advanced metastasis. Thus, there is a dire need to implement new treatment approaches to combat this dreadful disease. Cancer stem cells (CSCs), being critical players of tumors can be the potential target for therapy. Currently, cancer stem cell therapy is gaining much attention from researchers because of its ability to target the CSCs, which are responsible for tumor initiation, progression, metastasis, therapeutic resistance, and recurrence. While most conventional treatment strategies target fast-growing tumor cells, CSCs may remain in the latent stage for extended periods thereby escaping the traditional therapies and leading to treatment resistance. Hence, specific targeting of the tumor-initiating cells has become the heart of cancer research, aiming at the complete elimination of malignancies. Major strategies against CSCs include targeting surface CSC biomarkers, blockage of self-renewal signaling pathways (Wnt, Nanog, Hippo/YAP, Notch, PTEN, Hedgehog, and/or STAT3), genetic targeting of CSCs, cell therapy, RNA interference utilizing miRNAs. Based on this concept, the present chapter summarizes the current strategies and the lead molecules which have found their route to preclinical and clinical studies. Since the evolution of clinical trials targeting CSCs holds a sanguine promise of affecting cancer medicine. This chapter will further throw light on rapid advancement made in this field, shortcomings faced in targeting CSCs, and several critical issues that are yet to be resolved.

Keywords: Apoptosis, Angiogenesis, Cancer recurrence, Cancer stem cells, CSC biomarkers, CSC niche, CSC origin, Differentiation, Immunotherapy, Metastasis, Mutation, Oncogenic signaling, Plasticity, Self renewal, Stemness, Targeted therapy, Transformation, Treatment resistance, Tumorigenesis, VSELs.