OC-SLCs were isolated through sphere formation by cultivating the OC2 cell line in defined serum-free medium. Differential expression profiles of cell-surface stemness markers between enriched OC-SLCs and parental OSCC cells were elucidated by flow cytometry. Expression of excision repair cross-complementation group 1 (ERCC1) by OC-SLCs was examined by an RT-PCR and Western blotting.
Initially, significant sphere formation (OC-SLCs) was observed in OC2 cells. Enriched OC-SLCs highly expressed stem-cell surface markers (CD117 and CD133) and the ABC transporter gene (ABCG2). Enhanced chemoresistance to cisplatin was also noted in OC-SLCs. Further, the chemoresistance of OC-SLCs to cisplatin was possibly correlated with ERCC1 upregulation in OC-SLCs.
In summary, these results suggest that OC-SLCs may play a vital role in tumor recurrence due to resistance to cisplatin. Additionally, ERCC1 upregulation might be involved in platinum resistance in oral CSCs.