Early urinary protein changes in the tumor-forming process of the NuTu-19 lung metastasis

Abstract

The early detection of cancer is essential for effective intervention. Urine, which lacks homeostatic control, has been used to reflect early systemic changes in subcutaneous cancer models. However, urine has not been used to predict whether tumors will be formed in animal models. In this study, a cancer model was established by the tail-vein injection of 2 million NuTu-19 tumor cells. Approximately half of the rats formed lung metastatic carcinoma tumors. Urine samples were randomly selected from 4 tumor-forming rats and 4 non-tumor-forming rats on day 0/12/27/39/52 and analyzed by label-free proteomic quantitative analysis. Compared to day 0, a total of 180 and 118 urinary proteins in tumor-forming and non-tumor-forming rats, respectively, showed significant changes. Functional enrichment analysis of the differential proteins in tumor-forming rats revealed similar events during cancer metastasis cascades and tumor progression, such as the migration of tumor cell lines, coagulation system, TGF-β signaling, the STAT3 pathway and the adhesion of myeloid cells and alveolar macrophages. The differential proteins in non-tumor-forming rats were associated with agranulocyte/granulocyte adhesion and diapedesis, glutathione biosynthesis, IL-12 signaling and vitamin metabolism. After validation by parallel reaction monitoring (PRM) targeted proteomics quantitative analysis, a total of 22 urinary proteins showed significant changes in the early phase of the lung tumor formation process, 5 of which have been associated with the mechanisms of lung cancer, while 3 have been suggested as lung cancer biomarkers. Another 14 urinary proteins showed significant changes in the early phase in non-tumor-forming rats. Our results indicate that urine proteins could differentiate early tumor-forming and non-tumor-forming status.

Early urine proteome changes in an implanted bone cancer rat model

“…In the model of focal segmental glomerulosclerosis induced by doxorubicin, the urinary proteins were continuously changing with disease progression [7]. There are other models of organ diseases as follows: bleomycin-induced pulmonary fibrosis model [8], experimental autoimmune myocarditis model [9], rat model of bacterial meningitis [10], glioblastoma animal model [11], tumor model of the subcutaneous implantation of Walker 256 cells [12], rat model of chronic pancreatitis induced by diethyldithiocarbamate [13], rat model of NuTu-19 lung metastasis [14], Walker 256 intracerebral tumor model [15], and Walker 256 lung metastasis rat model [16]. The urinary proteome changes significantly before the clinical signs and histopathological changes have occurred.…”