Characterisation of a subpopulation of CD133(+) cancer stem cells from Chinese patients with oral squamous cell carcinoma

Cancer stem cells (CSCs) play a critical role in cancer development and growth. The aim of this study was to identify and isolate CSCs from populations of primary oral squamous cell carcinoma (OSCC) cells, which were obtained from OSCC specimens and identified by cell morphology and immunohistochemical staining for keratin. CD133(+) cells detected by flow cytometry comprised 0.41 ± 0.06% of primary OSCC cells and were isolated from primary OSCC cell populations using magnetic-activated cell sorting, revealing that 93.39% of high-purity CD133(+) cells were in the G0/G1 phase of the cell cycle. Additionally, the growth rate of CD133(+) cells was higher than that of CD133(−) cells, and in vivo tumourigenesis experiments showed that the tumourigenic ability of CD133(+) cells was markedly stronger than that of CD133(−) cells. Moreover, CD133(+) cells showed increased chemotherapeutic resistance to cisplatin and higher self-renewal ability according to sphere-formation assay, as well as higher mRNA levels of stemness-associated genes, including NANOG, SOX2, ALDH1A1, and OCT4. These results indicated that OSCC cells, which share certain characteristics of CSCs, harbour CD133(+) cells potentially responsible for OSCC aggressiveness, suggesting CD133 as a potential prognostic marker and therapeutic target.