Inhibition of HSP47 during the transition from solid to ascitic form of Sarcoma 180 in vivo.

HSP47, a collagen-binding stress protein, has transformation-sensitivity; that is, the synthesis of HSP47 decreases after malignant transformation. We examined the expression of HSP47 in transplanted tumours by Western blotting. While HSP47 was not detected in ascites tumours including Ehrlich, P388 and Sarcoma 180, marked expression of HSP47 was observed in solid tumours such as B16, B16-BL6 and Sarcoma 180. The expression of HSP47 in Sarcoma 180 cells disappeared completely after these solid tumour cells were dispersed and inoculated intraperitoneally. These findings suggested an important role of HSP47 as a marker for tumour malignancy.