OBJECT: Chordoma is a rare type of malignant bone tumor and is known to arise 
from the remnants of the notochord. Resistance to chemotherapy makes the 
treatment of chordoma difficult; therefore, new approaches need to be developed 
to cure this disease. Differentiation therapy, using various differentiating 
agents, is attracting oncologists as a common therapeutic method to treat other 
tumors. Based on forcing cells to mature into other lineages, differentiation 
therapy might be an available method to treat chordomas in addition to 
conventional therapies.
METHODS: In this study a chordoma cell line, U-CH1, was exposed to several 
chemotherapeutic agents including vincristine, doxorubicin, cisplatin, 
etoposide, fludarabine, methotrexate, nilotinib, and imatinib mesylate under 
appropriate conditions. The first group of U-CH1 cells was exposed to drugs only 
and the second group of cells was exposed to the simultaneous treatment of 1 μM 
all-trans retinoic acid (ATRA) and chemotherapeutic agents in differentiation 
therapy. The efficacy of the differentiation method was assessed by measuring 
the viability of U-CH1 cells.
RESULTS: Vincristine, doxorubicin, etoposide, cisplatin, and fludarabine, each 
at a concentration of 10 μM, decreased the number of chordoma cells when given 
alone down to 11%, 0%, 30%, 67%, and 3%, respectively. Etoposide and cisplatin, 
each at a concentration of 10 μM, reduced the percentage of viable chordoma 
cells in a more effective way when given with 1 μM ATRA simultaneously, reducing 
the number of viable cells to 14% and 9%, respectively. On the other hand, 
imatinib and nilotinib, each at a concentration of 3 μM, as well as 10 μM 
methotrexate, showed no decrease in the number of cancer cells.
CONCLUSIONS: The results suggest that chordoma cells may be treated using the 
differentiation method in a more effective way than when they are treated with 
chemotherapeutic agents alone. This new approach may be an alternative method to 
conventional therapies in the treatment of chordoma.