Changes in the urinary proteome in a patient-derived xenograft (pdx) nude mouse model of colorectal tumor

Abstract

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 4318 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.