Bone Metastasis in Renal Cell Carcinoma is Preprogrammed in the Primary Tumor and Caused by AKT and Integrin α5 Signaling

Bone metastasis develops in 30% of all patients with renal cell carcinoma. We elucidated the mechanisms that lead to and predict bone metastasis of renal cell carcinoma.Nine renal cell carcinoma primary cell lines and 30 renal cell carcinoma tissue specimens (normal and tumor tissue) were collected from 3 patients with no metastasis and 10 with lung or bone metastasis within 5 years after nephrectomy. Cell migration was analyzed in a Boyden chamber and proliferation was assessed by bromodeoxyuridine incorporation. Adhesion to fibronectin, and collagen I and IV was determined after cell staining. The expression and/or activity of cellular signaling molecules was quantified by Western blot.Co…