Chapter 3 - Cancer stem cell research: a phosphoproteomic approach

Abstract

Cancer stem cells (CSCs) occur in tumors with self-renewal properties, play an important role in the initiation, metastasis, and relapse of cancer, and are resistant to chemotherapy. The CSCs were first reported in leukemia and later in several cancers, including breast cancer, melanoma, and colon cancer. The inadequacy of comprehensive eradication of tumor-initiating CSCs is still the biggest challenge. Untreated CSCs are responsible for relapse in several cancers, as CSCs were successfully able to initiate the cancer and are resistant to chemotherapy and radiotherapy. The CSCs have become competent targets for cancer therapeutics, and understanding the signaling processes of the CSCs will help in cancer therapeutics. The posttranslational modification, specifically phosphorylation, regulates a myriad of inter and intracellular signaling processes in CSCs during the initiation, progression, and relapse of cancer. Phosphoproteomics may help to decipher the complex signaling processes of CSCs, including the activation and deactivation of kinases and phosphatases, which can provide novel targets for cancer therapeutics.