Patient-derived osteosarcoma cells are resistant to methotrexate

Area of Science:

• Oncology
• Cancer Biology
• Biomedical Research

Background:

• Osteosarcoma is the most common bone cancer in young people.
• Survival rates for osteosarcoma have stagnated since the 1990s despite chemotherapy.
• Cancer stem cells (CSCs) contribute to chemotherapy resistance in osteosarcoma.

Purpose of the Study:

• To investigate the impact of chemotherapy on cancer stem cell markers in osteosarcoma.
• To evaluate chemotherapy's effect on patient-derived osteosarcoma cells in vitro and in vivo.

Main Methods:

• Utilized low-passage patient-derived osteosarcoma cells and cells directly from patients.
• Assessed in vitro sensitivity to methotrexate, cisplatin, and doxorubicin.
• Monitored expression of stem cell markers (OCT4, SOX2, SSEA4) post-chemotherapy.
• Evaluated in vivo tumor growth in mice using combination chemotherapy regimens.

Main Results:

• Osteosarcoma cells showed resistance to methotrexate but sensitivity to cisplatin and doxorubicin in vitro.
• Cisplatin and doxorubicin decreased SOX2 and OCT4 expression; methotrexate increased SSEA4 expression.
• Combination of cisplatin and doxorubicin inhibited tumor growth in vivo, but adding methotrexate did not.

Conclusions:

• Chemotherapy differentially affects stem cell markers in osteosarcoma.
• Methotrexate's effect on SSEA4 may contribute to treatment resistance.
• Current therapeutic strategies for osteosarcoma may require reevaluation.