Aldehyde Dehydrogenase 1 (ALDH1) Is a Potential Marker for Cancer Stem Cells in Embryonal Rhabdomyosarcoma.

Cancer stem cells (CSCs) are defined as a small population of cancer cells with the properties of high self-renewal, differentiation, and tumor-initiating functions. Recent studies have demonstrated that aldehyde dehydrogenase 1 (ALDH1) is a marker for CSCs in adult cancers. Although CSCs have been identified in some different types of pediatric solid tumors, there have been no studies regarding the efficacy of ALDH1 as a marker for CSCs. Therefore, in order to elucidate whether ALDH1 can be used as a marker for CSCs of pediatric sarcoma, we examined the characteristics of a population of cells with a high ALDH1 activity (ALDH1high cells) in rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children. We used the human embryonal RMS (eRMS) cell lines RD and KYM-1, and sorted the cells into two subpopulations of ALDH1high cells and cells with a low ALDH1 activity (ALDH1low cells). Consequently, we found that the ALDH1high cells comprised 3.9% and 8.2% of the total cell population, respectively, and showed a higher capacity for self-renewal and tumor formation than the ALDH1low cells. With regard to chemoresistance, the survival rate of the ALDH1high cells was found to be higher than that of the ALDH1low cells following treatment with chemotherapeutic agents for RMS. Furthermore, the ALDH1high cells exhibited a higher degree of pluripotency and gene expression of Sox2, which is one of the stem cell markers. Taken together, the ALDH1high cells possessed characteristics of CSCs, including colony formation, chemoresistance, differentiation and tumor initiation abilities. These results suggest that ALDH1 is a potentially useful marker of CSCs in eRMS.

Increased expression of survivin in hepatoblastoma after chemotherapy.

BACKGROUND: Survivin, an inhibitor of apoptosis, has been reported to be associated with a worse prognosis in some malignancies. However, its expression in hepatoblastoma (HB) remains to be elucidated. We assessed the survivin expression in HB specimens collected before and after chemotherapy to elucidate the impact of survivin on the outcome of HB therapy. METHODS: HB specimens were collected before and after 2 to 4 cycles of cisplatin-based chemotherapy from 16 patients. The survivin expression level was assessed by immunohistochemical staining and real-time polymerase chain reaction. RESULTS: Out of 16, 12 HB sections collected before chemotherapy were positive for survivin as determined by immunohistochemical staining. The intensity of survivin expression was found to significantly increase after chemotherapy. Surprisingly, all of the HB specimens obtained after chemotherapy were positive for survivin. The expression of survivin messenger ribonucleic acid from a human HB cell line, Huh-6 was significantly higher when the cells were cultured with cis-diamminedichloroplatinum(II) than when the cells were cultured without the drug. CONCLUSION: Our results indicate that most of the primary HB tissue specimens express survivin, and its expression increased after chemotherapy, thus suggesting that survivin may concern with the survival of tumor cells, therefore be a candidate for the target of the treatment of HB.