Dynamic urinary proteomic analysis in a Walker 256 intracerebral tumor model

Abstract

Background Patients with primary and metastatic brain cancer have an extremely poor prognosis, mostly due to the late diagnosis of disease. Urine, which lacks homeostatic mechanisms, is an ideal biomarker source that accumulates early and highly sensitive changes to provide information about the early stage of disease. Methods A rat model mimicking the local tumor growth process in the brain was established with intracerebral Walker 256 (W256) cell injection. Urine samples were collected on days 3, 5, and 8 after injection, and then analyzed by liquid chromatography coupled with tandem mass spectrometry. Results In the intracerebral W256 model, no obvious clinical manifestations or abnormal magnetic resonance imaging (MRI) signals were found on days 3 or 5; at these time points, 9 proteins were changed significantly in the urine of all eight tumor rats. On day 8, when tumors were detected by MRI, 25 differential proteins were identified, including 10 that have been reported to be closely related to brain metastasis or primary tumors. The differential urinary proteome was compared with those from the subcutaneous W256 model and the intracerebral C6 model. Few differential proteins overlapped, and specific differential protein patterns were observed among the three models. Conclusions These findings demonstrate that early changes in the urine proteome can be detected in the intracerebral W256 model. The urinary proteome can reflect the difference when tumor cells with different growth characteristics are inoculated into the brain and when identical tumor cells are inoculated into different areas, specifically, the subcutis and the brain.

Urine proteome changes in rats subcutaneously inoculated with approximately ten tumor cells

“…When comparing differential proteins identified in our research to W256 subcutaneously tumor-bearing model (Wu, Guo & Gao, 2017a) and intracerebral W256 tumor model (Zhang et al, 2019), we found that the proportion of overlapping proteins was small, and more than half of the differential proteins in each of the three tumor models were unique (Fig. S2).…”

“…In addition, the urine proteome has been applied to detect tumors in various tumor-bearing animals. For example, (i) in W256 subcutaneously tumor-bearing rats, a total of ten differential urinary proteins were identified before a tumor mass was palpable (Wu, Guo & Gao, 2017a); (ii) in the intracerebral W256 tumor model, nine urinary proteins changed significantly before any obvious clinical manifestations or abnormal magnetic resonance imaging (MRI) signals (Zhang et al, 2019); (iii) in the glioma rat model, a total of thirty differential proteins were identified before MRI (Ni et al, 2018a); (iv) a total of seven urinary proteins changed in both lung tumor-bearing mice and lung cancer patients, indicating their potential roles in the early detection of lung cancer (Zhang et al, 2015); (v) in a urothelial carcinoma rat model, differential urinary proteins from upregulated biological processes might be seen as candidate biomarkers (Ferreira et al, 2015). All of these studies were performed involving thousands of tumor cells; however, no tumor starts from a thousand tumor cells.…”

Dynamic Changes of Urine Proteome in Rat Models Inoculated with Two Different Hepatoma Cell Lines

“…Specifically, animal models can minimize the influences of confounding factors and can be used to monitor whole processes from disease onset, which will be helpful for discovery of early biomarker candidates and future clinical validation. Animal models such as myocarditis [ 5 ], Alzheimer's [ 6 ], liver fibrosis [ 7 ], glioma [ 8 ], pulmonary fibrosis [ 9 ], intracerebral W-256 [ 10 ], and chronic pancreatitis models [ 11 ] have been widely used to research different diseases. The related studies have indicated that animal models are effective tools for identification of early urinary protein biomarkers, which can help elucidate the starting point of a disease and the dynamic changes in the urine proteome that occur throughout disease development.…”

“…Recent studies have shown that the urine proteome has great potential not only for discovering early biomarker candidates but also for distinguishing some subtle differences, such as the differences between the same types of tumor cells grown in different organs [ 12 ]. Different animal models have been established by injection of W-256 carcinosarcoma cells into different organs, including the W-256 subcutaneous model [ 2 ], the W-256 intracerebral tumor model [ 10 ], the W-256 liver tumor model [ 12 ], and the W-256 lung metastasis model [ 13 ]. For these four models, changes in the urinary proteome can be identified at early stages, even before histological examination or magnetic resonance imaging (MRI) reveals changes.…”

Changes in the urinary proteome in rats with regular swimming exercise

“…Recent studies have also shown that the urine proteome has potential for differential diagnosis. For example, early urinary proteins were different when the same tumor cells were grown in different organs [6, 11–14] and when different cells were injected into the same organ [12, 15]. Furthermore, several clinical studies performed urine proteomics to discover diagnostic biomarkers, such as for gastric cancer [16] and familial Parkinson’s disease [17].…”