TY - JOUR AB - Cancer stem cells are a sub‑population of cancer cells with self‑renewal activity that play key roles in tumor resistance to chemotherapy and radiation. Several cancer stem cell markers have been identified to correlate with clinical prognosis. However, which marker is associated with which cancer stem cell characteristic is unclear. The present study aimed to clarify the relationship between cancer stem cell markers associated with drug resistance acquisition and the characteristics of cancer stem cells. We generated cisplatin‑resistant head and neck squamous cell carcinoma cells by culturing cells in increasing concentrations of cisplatin. The cisplatin‑resistant head and neck squamous cell carcinoma cells also acquired multidrug resistance and were named resistant HSC‑3 (R HSC‑3) cells. R HSC‑3 showed no differences in cell proliferation or cell cycle distributions compared with parental cells. R HSC‑3 cells showed increased drug excretion ability and elevated expression of ATP‑binding cassette subfamily G member 2 (ABCG2), a drug excretion pump. R HSC‑3 cells also highly expressed CD44, a cancer stem cell marker, and exhibited enhanced cell invasion and spheroid formation abilities. Furthermore, the stem cell‑related factor SRY‑box transcription factor 9 (SOX9) was identified as increased in R HSC‑3 cells by microarray analysis. Knockdown experiments showed that SOX9 and ABCG2 were involved in the drug excretion ability of R HSC3 cells and ABCG2 was involved in the spheroid formation ability of R HSC‑3 cells. These results indicate that CD44, SOX9 and ABCG2 expression levels were enhanced in head and neck squamous cell carcinoma cells that acquired multidrug resistance and that these molecules are important for maintaining cancer stem cell characteristics. Overall, regulating CD44, SOX9 and ABCG2 may be a strategy to inhibit cancer stem cells. AD - Department of Natural Products Chemistry, Faculty of Pharmaceutical Sciences Aomori University, Aomori, Aomori 030‑0943, Japan Department of Oral Biochemistry, Asahi University School of Dentistry, Mizuho, Gifu 501‑0296, Japan Department of Oral and Maxillofacial Surgery, Nagoya Tokushukai General Hospital, Kasugai, Aichi 487‑0016, Japan AU - Murakami,Koichi AU - Umemura,Naoki AU - Adachi,Makoto AU - Motoki,Masahiro AU - Ohkoshi,Emika DA - 2022/12/01 DO - 10.3892/etm.2022.11658 IS - 6 JO - Exp Ther Med KW - ABCG2 CD44 antigen cisplatin resistance chemotherapeutic drug head and neck squamous cell carcinoma SRY‑box transcription factor 9 PY - 2022 SN - 1792-0981 1792-1015 SP - 722 ST - ABCG2, CD44 and SOX9 are increased with the acquisition of drug resistance and involved in cancer stem cell activities in head and neck squamous cell carcinoma cells T2 - Experimental and Therapeutic Medicine TI - ABCG2, CD44 and SOX9 are increased with the acquisition of drug resistance and involved in cancer stem cell activities in head and neck squamous cell carcinoma cells UR - https://doi.org/10.3892/etm.2022.11658 VL - 24 ER -