The isolation, characterisation and role of cancer stem cells in oral cancer progression

Abstract Introduction: Oral cancer has a poor prognosis due to late detection and the high risk of recurrence and development of secondary tumours at distant sites. This may be attributed to the fact that conventional anticancer therapy does not eradicate the cancer stem cells which are a subset of the tumour cell population characterised by unique properties including their capability for indefinite self-renewal, proliferation and differentiation to diverse heterogeneous cell lineages that form the bulk of the tumour. Moreover, they are highly tumourigenic, play a crucial role in invasion and metastasis and also have the ability to resist anticancer therapy. Identifying and isolating CSCs is considered an important step in order to study their biological characteristics accurately with the aim of subsequently targeting and eradicating them. CSCs isolation has previously been mainly based on the expression of specific markers or clonogenicity as well as the rapid adherence of such cells to ECM proteins. Aims: The purpose of this study to develop functional assays (adhesion and chemoresistance) to isolate CSCs from OSCC cell lines and investigate the stem cell characteristics of the sorted cells compared to unsorted cells. Additionally, we aimed to investigate the stability of the isolated phenotypes and determine whether the CSCs signal differently from non-CSCs to stromal cells (fibroblasts)