Characterization of pulmonary intimal sarcoma cells isolated from a surgical specimen: In vitro and in vivo study

Pulmonary intimal sarcoma (PIS) constitutes a rare sarcoma originating from the intimal cells of pulmonary arteries. The pathogenesis of PIS remains to be elucidated and specific treatments have not been established; therefore, prognosis is generally poor. The purpose of our study was to isolate and characterize PIS cells from a specimen resected from a patient with PIS. The surgical specimen was minced and incubated, and spindle-shaped and small cells were successfully isolated and designated as PIS-1. PIS-1 cells at passages 8-9 were used for all in vitro and in vivo experiments. Immunocytochemistry showed that PIS-1 cells were positive for vimentin, murine double minute 2, and CD44 and negative for α-smooth muscle actin, CD31, von Willebrand factor, and desmin. PIS-1 cells exhibited the hallmarks of malignant cells including the potential for autonomous proliferation, anchorage-independent growth, invasion, genetic instability, and tumorigenicity in severe combined immunodeficiency mice. The PIS-1 cells highly expressed tyrosine kinase receptors such as platelet-derived growth factor receptor, and vascular endothelial growth factor receptor 2. Pazopanib, a multi-targeted tyrosine kinase inhibitor, suppressed the proliferation of PIS-1 cells in vitro and the growth of tumors formed from xenografted PIS-1 cells. A PIS cell line was thus successfully established. The PIS-1 cells highly expressed tyrosine kinase receptors, which may be a target for treatment of PIS.