[gammadelta T cells stimulated by zoledronate kill osteosarcoma cells]

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Osteosarcoma is a primary bone malignancy with limited treatment options.
• Gamma delta T (γδT) cells are a distinct subset of T lymphocytes with innate and adaptive immune functions.
• Zoledronate is a bisphosphonate used in treating bone diseases and has shown immunomodulatory effects.

Purpose of the Study:

• To investigate the in vitro and in vivo cytotoxicity of human γδT cells, stimulated by zoledronate, against the HOS osteosarcoma cell line.
• To elucidate the mechanisms underlying γδT cell-mediated cytotoxicity against osteosarcoma.
• To evaluate the therapeutic potential of γδT cell therapy in a preclinical osteosarcoma model.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) from healthy donors were stimulated with zoledronate and cultured with IL-2 to expand γδT cells.
• Cytotoxicity was assessed using the lactate dehydrogenase (LDH) release assay against the HOS cell line.
• Mechanisms were explored by blocking γδT cell receptor (γδTCR) and NKG2D pathways.
• In vivo efficacy was evaluated in a murine model by comparing tumor growth in untreated and γδT cell-treated groups.

Main Results:

• Zoledronate stimulation yielded a high percentage (95±3%) of γδT cells.
• γδT cells demonstrated dose-dependent cytotoxicity against HOS cells in vitro.
• Blocking NKG2D significantly reduced γδT cell-mediated killing, indicating its crucial role.
• In vivo, γδT cell therapy resulted in a 42.78% tumor inhibition rate.

Conclusions:

• Zoledronate effectively generates pure human γδT cells with potent anti-osteosarcoma activity.
• These γδT cells exhibit significant in vitro and in vivo cytotoxicity against osteosarcoma.
• γδT cell therapy represents a promising approach for osteosarcoma treatment.