Bone metastases are widespread among advanced cancer patients, but a curative treatment is still unavailable. Beyond specializing in storing energy as fat, adipocytes can support tumor growth and metastasis in bone marrow and other organs1,2,3,4,5,6. Moreover, adipocytes play an essential role in regulating cancer cell biology7,8,9,10 and metabolism4,11,12,13,14,15,16, as well as in bone metastasis1,4,12. In the bone marrow niche, adipocytes can also affect the biological behavior of cancer cells4,6,17. The interplay between bone marrow adipocytes and cancer cells with osteotropism is significant for an understanding of bone metastasis. However, little is known.
Based on the current studies, various methods are applied to adipocytes, including two- or three-dimensional (2/3D) and ex vivo cultures17,18,19,20,21. Recently, Herroon et al. designed a new 3D-culture approach to study interactions of bone marrow adipocytes with cancer cells22. Although the 3D coculture is optimal for mimicking physiological interactions between adipocytes and cancer cells in vivo, it suffers from poor reproducibility22,23. In comparison to a 2D coculture system, a 3D coculture system may provide different cellular phenotypes, such as cell morphology21,22,24,25,26. Moreover, the ex vivo culture of isolated cancellous bone tissue fragments can lead to a robust outgrowth of adipocytes from cultured bone marrow cells17.
In contrast to these previous models, however, the 2D cell culture model remains a classic, reliable, and easy technique for quickly scanning candidate molecules and the phenotypes changed in either adipocytes or cancer cells in vitro1,4,6,12,15,27. To better understand the crosstalk between bone marrow adipocytes and melanoma cells, we provide a detailed protocol for a 2D coculture system of bone marrow adipocytes with melanoma cells.