Dynamic changes of urine proteome in a Walker 256 tumor-bearing rat model

Urinary protein changes during the short-term growth and development of rats

Can the urine proteome reflect short-term changes in the growth and development of animals? Do short-term developmental effects on urinary protein need to be considered when performing urine marker studies using model animals with faster growing periods? In this study, urine samples were collected from 10 Wistar rats aged 6-8 weeks 3 and 6 days apart. The results showed that the urine proteome could sensitively reflect short-term growth and development in rats. For example, comparing the urine proteome of Day 0 and Day 6, 195 differential proteins were identified after screening (FC ≥ 1.5 or ≤ 0.67, P < 0.05), and verified by randomization, the average number of randomly generated differential proteins was 17.99. At least 90.77 % of the differential proteins were not randomly generated. This finding demonstrates that the differential proteins identified in the samples collected at different time points were not randomly generated. A large number of biological processes and pathways related to growth and development were enriched, which shows that the urine proteome reflects the short-term growth and development of rats, and provides a means for in-depth and meticulous study of growth and development. Moreover, an interfering factor in animal experiments using 6- to 8-week-old rats to construct models was identified. The results of this study demonstrated that there were differences in the urinary proteome in rats aged 6-8 weeks only 3-6 days apart, which suggests that the sensitivity of urinary proteomics is high and shows the sensitive and precise response of the urinary proteome to body changes.

L-glutamine supplementation reduced morphological damage in the renal glomerulus of rats with Walker-256 tumor

PURPOSE

To evaluate the effects of the experimental subcutaneous Walker-256 tumor and L-glutamine supplementation, an antioxidant, on the glomerular morphology of rats.

METHODS

Twenty Wistar rats were distributed into four groups (n = 5): control (C); control treated with 2% L-glutamine (CG); rats with Walker-256 tumor (WT); and rats with Walker-256 tumor treated with 2% L-glutamine (WTG). Renal histological samples were submitted to periodic acid-Schiff and Masson's Trichrome staining to analyze glomerular density, morphometry of glomerular components and glomerulosclerosis; and to immunohistochemistry for fibroblast growth factor-2 (FGF-2).

RESULTS

WT showed 50% reduction in body mass gain and cachexia index > 10%, while WTG demonstrated reduction in cachexia (p < 0.05). WT revealed reduction of glomerular density, increase in the glomerular tuft area, mesangial area, matrix in the glomerular tuft, decrease in the urinary space and synechia, and consequently higher glomerulosclerosis (p < 0.05). L-glutamine supplementation in the WTG improved glomerular density, and reduced glomerular tuft area, urinary space, mesangial area, and glomerulosclerosis compared to WT(p < 0.05). WT showed higher collagen area and FGF-2 expression compared to C (p < 0.05). WTG presented lower collagen fibers and FGF-2 expression compared to WT (p < 0.05).

CONCLUSIONS

L-glutamine supplementation reduced cachexia and was beneficial for glomerular morphology of the rats, as well as it reduced kidney damage and improved the remaining glomeruli morphology.

Urine proteomic analysis of the rat e-cigarette model

Background

We were curious if the urinary proteome could reflect the effects of e-cigarettes on the organism.

Methods

Urine samples were collected from a rat e-cigarette model before, during, and after two weeks of e-cigarette smoking. Urine proteomes before and after smoking of each rat were compared individually, while the control group was set up to rule out differences caused by rat growth and development.

Results

Fetuin-B, a biomarker of chronic obstructive pulmonary disease (COPD), and annexin A2, which is recognized as a multiple tumour marker, were identified as differential proteins in five out of six smoking rats on day 3. To our surprise, odourant-binding proteins expressed in the olfactory epithelium were also found and were significantly upregulated. Pathways enriched by the differential proteins include the apelin signalling pathway, folate biosynthesis pathway, arachidonic acid metabolism, chemical carcinogenesis-DNA adducts and chemical carcinogenesis-reactive oxygen species. They have been reported to be associated with immune system, cardiovascular system, respiratory system, etc.

Conclusions

Urinary proteome could reflect the effects of e-cigarettes in rats.

Comparison of urine proteomes from tumor-bearing mice with those from tumor-resected mice

Objective

This study aimed to address on the most important concern of surgeons-whether to completely resect tumor. Urine can indicate early changes associated with physiological or pathophysiological processes. Based on these ideas, we conducted experiments to explore changes in the urine proteome between tumor-bearing mice and tumor-resected mice.

Method

The tumor-bearing mouse model was established with MC38 mouse colon cancer cells, and the mice were divided into the control group, tumor-resected group, and tumor-bearing group. Urine was collected 7 and 30 days after tumor resection. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was used to identify the urine proteome, which was analyzed for differentially expressed proteins and functional annotation.

Results

(1) Seven days after tumor resection, 20 differentially expressed proteins distinguished the tumor-resected group and the tumor-bearing group. The identified biological processes included circadian rhythm, Notch signaling pathway, leukocyte cell-cell adhesion, and heterophilic cell-cell adhesion via plasma membrane cell adhesion molecules. (2) Thirty days after tumor resection, 33 differentially expressed proteins distinguished the tumor-resected group and the tumor-bearing group. The identified biological processes included cell adhesion; complement activation, the alternative pathway; the immune system process; and angiogenesis. (3) The difference in the urine proteome between the tumor-resected group and the healthy control group was smaller 30 days after tumor resection.

Conclusion

Changes in the urinary proteome can reflect the complete resection of MC38 tumors.

Changes in the urinary proteome in rats with regular swimming exercise

Purpose

Urine can sensitively reflect early pathophysiological changes in the body. The purpose of this study was to explore the changes of urine proteome in rats with regular swimming exercise.

Methods

In this study, experimental rats were subjected to daily moderate-intensity swimming exercise for 7 weeks. Urine samples were collected at weeks 2, 5, and 7 and were analyzed by using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS).

Results

Unsupervised clustering analysis of all urinary proteins identified at week 2 showed that the swimming group was distinctively different from the control group. Compared to the control group, a total of 112, 61 and 44 differential proteins were identified in the swimming group at weeks 2, 5 and 7, respectively. Randomized grouping statistical analysis showed that more than 85% of the differential proteins identified in this study were caused by swimming exercise rather than random allocation. According to the Human Protein Atlas, the differential proteins that have human orthologs were strongly expressed in the liver, kidney and intestine. Functional annotation analysis revealed that these differential proteins were involved in glucose metabolism and immunity-related pathways.

Conclusion

Our results revealed that the urinary proteome could reflect significant changes after regular swimming exercise. These findings may provide an approach to monitor the effects of exercise of the body.

Early disease biomarkers can be found using animal models urine proteomics

INTRODUCTION

Early disease detection is a prerequisite for early intervention. Urine is not subjected to homeostatic control, and therefore, it accumulates very early changes associated with disease processes, some of which may be used as biomarkers. Animal models must be used to identify urinary changes associated with very early stages of diseases to avoid potential interfering factors and obtain urine samples at a sufficiently early time point before pathological or clinical manifestations occur.

AREAS COVERED

We reviewed recent (from 2009-2020) urine proteome studies using animal models of many diseases. We focused on early changes in urine proteome of animal models, particularly changes occurring prior to alterations in blood tests, light microscopy observations and clinical manifestations. Additional studies relevant to the topic were also extracted from the references of the cited papers. Changes in the urine proteome at different disease stages and the ability of the urine proteome to differentiate among different animal models are also discussed in this review.

EXPERT COMMENTARY

Urine proteomes of animal models may reflect early changes that occur even before changes in blood parameters, light microscopy observations and clinical manifestations, suggesting the potential use of urinary biomarkers for the very early detection of human diseases.

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

Urine can accumulate systemic changes with no mechanism to be stable, which may reflect early changes associated with physiological or pathophysiological processes. To explore the potential value of the urine proteome, two rat models were established by intrahepatic injection of two different hepatoma cell lines, CBRH-7919 and RH-35. Urine samples were collected and analyzed. Compared with controls, the two models exhibited different numbers and types of differentially expressed urinary proteins despite having similar histological results. The results were compared with the urine proteome of a Walker 256 (W-256) liver tumor model. The differentially expressed urinary protein patterns in the three models were different. These findings demonstrate that changes in the urine proteomes of the two models can be detected at early stages and that the patterns of differentially expressed urinary proteins can differ even when the histological results are similar. Urinary proteins have potential utility for distinguishing among different tumor cells grown in the same organ.

Early urinary protein changes during tumor formation in a NuTu-19 tail vein injection rat model

Early detection of cancer is essential for effective intervention. Urine has been used to reflect early changes in various tumor-bearing models. However, urine has not been used to predict whether tumors will form in animal models. In this study, a cancer model was established by tail vein injection of 2 million NuTu-19 tumor cells. Urine samples were randomly selected from tumor-forming and non-tumor-forming rats on day 0/12/27/39/52 and were analyzed by label-free and parallel reaction monitoring targeted proteomic quantitative analyses. In tumor-forming rats, differential proteins were associated with tumor cell migration, TGF-β signaling and the STAT3 pathway. A total of 9 urinary proteins showed significant changes in the early phase of lung tumor formation in all eight tumor-bearing rats. Differential proteins in non-tumor-forming rats were associated with glutathione biosynthesis, IL-12 signaling and vitamin metabolism. A total of 12 urinary proteins changed significantly in the early phase in all seven non-tumor-forming rats. Our small-scale pilot study indicated that (1) the urinary proteome reflects early changes during lung tumor formation and that (2) the urinary proteome can distinguish early tumor-forming rats from non-tumor-forming rats.

Early urine proteome changes in an implanted bone cancer rat model

In this study, Walker 256 cells were implanted into rat tibiae. Urine samples were then collected on days 3, 5, 7, and 13 and were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). With label-free quantification, 25 proteins were found to change significantly in the urine of the tumor group rats compared with the proteins in the urine of the control group rats; this was even the case when there were no significant lesions identified in the Computed Tomography (CT) examination. Among these differentially proteins, 7 were reported to be associated with tumor bone metastasis. GO analysis shows that the differential proteins on day 3 were involved in several responses, including the acute phase response, the adaptive immune response and the innate immune response. The differentially proteins on day 7 were involved in the mineral absorption pathway. The differentially proteins on day 13 were involved in vitamin D binding and calcium ion binding. These processes may be associated with bone metastasis. Our results demonstrate that urine could sensitively reflect the changes in the early stage of implanted bone cancer; this provides valuable clues for future studies of urine biomarkers for tumor bone metastasis.

Urinary biomarker discovery in gliomas using mass spectrometry-based clinical proteomics

Background

Gliomas are the most common primary malignant brain tumors and have a poor prognosis. Early detection of gliomas is crucial to improve patient outcomes. Urine accumulates systematic body changes and thus serves as an excellent early biomarker source.

Methods

At the biomarker discovery phase, we performed a self-controlled proteomics analysis by comparing urine samples collected from five glioma patients at the time of tumor diagnosis and after surgical removal of the tumor. At the biomarker validation phase, we further validated some promising proteins using parallel reaction monitoring (PRM)-based targeted proteomics in another cohort, including glioma, meningioma, and moyamoya disease patients as well as healthy controls.

Results

Using label-free proteome quantitation (LFQ), we identified twenty-seven urinary proteins that were significantly changed after tumor resection, many of which have been previously associated with gliomas. The functions of these proteins were significantly enriched in the autophagy and angiogenesis, which are associated with glioma development. After targeted proteomics validation, we identified a biomarker panel (AACT, TSP4, MDHM, CALR, LEG1, and AHSG) with an area under the curve (AUC) value of 0.958 for the detection of gliomas. Interestingly, AACT, LEG1, and AHSG are also potential cerebrospinal fluid or blood biomarkers of gliomas.

Conclusions

Using LFQ and PRM proteome quantification, we identified candidate urinary protein biomarkers with the potential to detect gliomas. This study will also provide clues for future biomarker studies involving brain diseases.

Early changes in the urine proteome in a rat liver tumour model

BACKGROUND

Urine, as a potential biomarker source among body fluids, can accumulate many early changes in the body due to the lack of mechanisms to maintain a homeostatic state. This study aims to detect early changes in the urinary proteome in a rat liver tumour model.

METHODS

The tumour model was established with the Walker-256 carcinosarcoma cell line (W256). Urinary proteins at days 3, 5, 7 and 11 were profiled by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Compared with controls, differential proteins were selected. Associations of differential proteins with cancer were retrieved.

RESULTS

At days 3, 5, 7 and 11, five, fifteen, eleven and twelve differential proteins were identified, respectively. Some of the differential proteins were reported to be associated with liver cancer. This differential urinary protein pattern was different from the patterns in W256 subcutaneous, lung metastasis and intracerebral tumour models.

CONCLUSIONS

This study demonstrates that (1) early changes in urinary proteins can be found in the rat liver tumour model; (2) urinary proteins can be used to differentiate the same tumour cells grown in different organs.

Regional Differences of the Urinary Proteomes in Healthy Chinese Individuals

Objective Urine is a promising biomarker source for clinical proteomics studies. Regional physiological differences are common in multi-center clinical studies. In this study, we investigate whether significant differences are present in the urinary proteomes of individuals from different regions in China. Methods In this study, morning urine samples were collected from healthy urban residents in three regions of China (Haikou, Xi'an and Xining) and urinary proteins were preserved using a membrane-based method (Urimem). The urine proteomes of 27 normal samples were analyzed using LC-MS/MS and compared among three regions. Functional annotation of the differential proteins among the three areas was analyzed using the DAVID online database, and pathway enrichment of the differential urinary proteins was analyzed using KEGG. Results We identified 1898 proteins from Urimem samples using label-free proteome quantification, of which 56 urine proteins were differentially expressed among the three regions (P < 0.05). Hierarchical clustering analysis showed that inter-regional differences caused less significant changes in the urine proteome than inter-sex differences. After gender stratification, 16 differential proteins were identified in male samples and 84 differential proteins were identified in female samples. Among these differential proteins, several proteins have been previously reported as urinary disease biomarkers. Conclusions Urimem will facilitate urinary protein storage for large-scale urine sample collection. Regional differences are a confounding factor influencing the urine proteome and should be considered in future multi-center biomarker studies.

Early urine proteome changes in the Walker-256 tail-vein injection rat model

Detection of cancer at its early stage is important for treatment. Urine, which is not regulated by homeostatic mechanisms, reflects early systemic changes throughout the whole body and can be used for the early detection of cancer. In this study, the Walker-256 tail-vein injection rat model was established to find whether the urine proteome could reflect early changes if tumor grown in lung. Urine samples from the control group (n = 7) and Walker-256 tail-vein injection group (n = 7) on days 2, 4, 6 and 9 were analyzed by label-free proteomic quantitative methods. On day 2, when lung tumor nodules did not appear, 62 differential proteins were identified. They were associated with epithelial cell differentiation, regulation of immune system processes and the classical complement activation pathway. On day 4, when lung tumor nodules appeared, 72 differential proteins were identified. They were associated with the innate immune response and positive regulation of phagocytosis. On day 6, when body weight began to decrease, 117 differential proteins were identified. On day 9, the identified 125 differential proteins were associated with the B cell receptor signaling pathway and the positive regulation of B cell activation. Our results indicate that (1) the urine proteome changed even on the second day after tail-vein injection of Walker-256 cells and that (2) compared to previous studies, the urine proteomes were different when the same cancer cells were grown in different organs.

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

Background

Biomarkers are changes associated with the disease. Urine is not subject to homeostatic control and therefore accumulates very early changes, making it an ideal biomarker source. Usually, we have performed urinary biomarker studies involving at least thousands of tumor cells. However, no tumor starts from a thousand tumor cells. We therefore examined urine proteome changes in rats subcutaneously inoculated with approximately ten tumor cells.

Methods

Here, we serially diluted Walker-256 carcinosarcoma cells to a concentration of 10²/mL and subcutaneously inoculated 0.1 mL of these cells into nine rats. The urine proteomes on days 0, 13 and 21 were analyzed by liquid chromatography coupled with tandem mass spectrometry.

Results

Hierarchical clustering analysis showed that the urine proteome of each sample at three time points were clustered into three clusters, indicating the good consistency of these nine rats when inoculated with the same limited tumor cells. Differential proteins on days 13 and 21 were mainly associated with cell adhesion, autophagic cell death, changes in extracellular matrix organization, angiogenesis, and the pentose phosphate pathway. All of these enriched functional processes were reported to contribute to tumor progression and could not be enriched through random allocation analysis.

Conclusions

Our results indicated that (1) the urine proteome reflects changes associated with cancer even with only approximately ten tumor cells in the body and that (2) the urine proteome reflects pathophysiological changes in the body with extremely high sensitivity and provides potential for a very early screening process of clinical patients.

Dynamic urinary proteomic analysis in a Walker 256 intracerebral tumor model

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.

Changes in the Urinary Proteome in a Patient-Derived Xenograft (PDX) Nude Mouse Model of Colorectal Tumor

In this report, the urinary proteome from a patient-derived xenograft (PDX) model was examined at the peptide level to study the origins of urinary proteins in tumor-bearing nude mice. Urine was collected from PDX mice before and after colorectal tumor implantation. A total of 4,318 unique peptides were identified, and 78 unambiguous human-origin peptides were discerned in the PDX model urine. Unlike the differential urinary protein composition of tumor-bearing immunocompetent rat models, the differential urinary proteins in the PDX model did not include host immune-response proteins. This study demonstrates that tumor-secreted proteins can be observed in the urine proteome of the PDX model. However, immune-response proteins, which are very early candidate tumor biomarkers, are not present in the urine of PDX model mice; this absence is due to immune deficiency. Therefore, immunodeficient animals may not be suitable models for searching for early immunity-associated tumor biomarkers in the urine.

Dynamic changes of urine proteome in a Walker 256 tumor-bearing rat model

Despite advances in cancer treatments, early diagnosis of cancer is still the most promising way to improve outcomes. Without homeostatic control, urine reflects systemic changes in the body and can potentially be used for early detection of cancer. In this study, a tumor-bearing rat model was established by subcutaneous injection of Walker 256 cells. Urine samples from tumor-bearing rats were collected at five time points during cancer development. Dynamic urine proteomes were profiled using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Several urine proteins that changed at multiple time points were selected as candidate cancer biomarkers and were further validated by multiple reaction monitoring (MRM) analysis. It was found that the urinary protein patterns changed significantly with cancer development in a tumor-bearing rat model. A total of 10 urinary proteins (HPT, APOA4, CO4, B2MG, A1AG, CATC, VCAM1, CALB1, CSPG4, and VTDB) changed significantly even before a tumor mass was palpable, and these early changes in urine could also be identified with differential abundance at late stages of cancer. Our results indicate that urine proteins could enable early detection of cancer at an early onset of tumor growth and monitoring of cancer progression.