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Analysis of organ selectivity in the metastatic behavior of Dunn osteosarcoma
Hideto Obata1, Shigeyuki Kuratsu, Atsumasa Uchida
1Department of Orthopaedic Surgery, Osaka University Medical School, Suita, Osaka, Japan.
Abstract:
In the current study, the authors established a novel metastatic model to analyze organ selective metastasis by osteosarcoma, using a murine cell line, Dunn osteosarcoma. The lung, liver, kidney, and spleen were resected from syngeneic donor mice, and a tissue fragment of the respective organs was transplanted subcutaneously into a recipient mouse. Two weeks later, tumor cells were injected intravenously and the formation of metastatic deposits in the ectopic transplants was examined. Ectopic lung transplants had a significantly higher incidence of metastasis than either liver or kidney transplants. When enzymatically dispersed organ cells that were embedded in agar gel were transplanted, intravenous injection of tumor cells also resulted in a higher metastatic rate in lung transplants than in either liver or kidney transplants. Photomicrographs and microangiographs of the transplants showed equivalent revascularization of the different organs. Radiolabeled tumor cells were deposited in equivalent amounts in the ectopic transplants of the different organs after intravenous injection. In addition, in vitro growth of tumor cells was stimulated by medium conditioned with lung tissue in a dose-dependent manner. These results suggest that organ selective metastasis by osteosarcoma is not defined anatomically or hemodynamically, but may be caused by tumor cells responding to possible paracrine factors emanating from the lung.
Insights
Osteosarcoma lung metastasis is not due to anatomical or blood flow factors. Instead, lung tissue may release factors that promote osteosarcoma tumor cell growth and metastasis.
Area of Science:
- Oncology
- Cancer Metastasis Research
Background:
- Organ-selective metastasis is a complex process in cancer progression.
- Osteosarcoma, a primary bone cancer, frequently metastasizes to the lungs.
Purpose of the Study:
- To establish a novel murine model for analyzing organ-selective metastasis of osteosarcoma.
- To investigate the underlying mechanisms driving lung metastasis in osteosarcoma.
Main Methods:
- A novel ectopic organ transplant model was developed using Dunn osteosarcoma cells in mice.
- Tissue fragments of lung, liver, and kidney were subcutaneously transplanted, followed by intravenous tumor cell injection.
- Tumor formation in ectopic transplants was assessed, alongside in vitro cell growth assays using conditioned media.
Main Results:
- Ectopic lung transplants exhibited a significantly higher incidence of osteosarcoma metastasis compared to liver or kidney transplants.
- Both intact tissue and dispersed organ cell transplants showed enhanced lung metastasis.
- Tumor cell deposition and revascularization were similar across ectopic organs, but lung-conditioned media dose-dependently stimulated tumor cell growth.
Conclusions:
- Osteosarcoma's organ selectivity for lung metastasis is not determined by anatomical or hemodynamic factors.
- Paracrine factors released by lung tissue likely play a crucial role in promoting osteosarcoma metastasis to the lungs.