Salivary proteomics in monitoring the therapeutic response of canine oral melanoma

Abstract

Saliva biomarkers are suitable for monitoring the therapeutic response of canine oral melanoma (COM), because saliva directly contacts the tumor, and saliva collection is non-invasive, convenient and cost effective. The present study aimed to investigate novel biomarkers from the salivary proteome of COM treated with surgery and a chemotherapy drug, carboplatin, 1–6 times, using a liquid chromatography–tandem mass spectrometry approach. The expression of a potential salivary biomarker, ubiquitin D (UBD), was observed and verified by western blot analysis. A significantly increased ratio of free UBD (fUBD) to conjugated UBD (cUBD) was shown in the pre-surgery stage (PreS) in OM dogs with short-term survival (STS) (less than 12 months after surgery) compared with that with long-term survival (more than 12 months after surgery). In dogs with STS, the ratio was also shown to be augmented in PreS compared with that after surgery, followed by treatment with carboplatin twice, 4 and 5 times [After treatment (AT)2, AT4 and AT5]. In addition, the expression of fUBD was enhanced in PreS compared with that of AT2 in the STS group. In conclusion, this study revealed that a ratio of fUBD to cUBD in PreS was plausibly shown to be a potential prognostic biomarker for survival in dogs with OM.

Mass spectrometry-based proteomics profiling of dogs with and without oral diseases: a systematic review

“…Eventually, 13 articles were included in the present systematic review (Fig. 1) [17][18][19][20][21][22][23][48][49][50][51][52][53].…”

“…MS-based proteomics studies of dogs with and without oral diseases were published between 2015 [52] and 2022 [22,48], of which most of the investigations were Fig. 1 Literature search outcomes following the PRISMA guidelines [39] performed in Thailand (n = 6) [17,[19][20][21][22]49], followed by the United Kingdom (n = 3) [18,48,51], Portugal (n = 2) [52,53], Canada (n = 1) [23], and the United States (n = 1) [18]. Overall, 439 dogs (range: 1-53; mean: 13) were utilized in the included studies, of which 172 were males and 154 were females.…”

“…Saliva was the most frequently used sample biofluid with 8 studies using unstimulated whole saliva (UWS; 500-1000 µL) [19][20][21][48][49][50][51][52], 1 used stimulated whole saliva (SWS; 100-1000 µL) [23], and 1 used both UWS and SWS [53]. Blood serum (500 µL) [22] and GCF [18] were used as the sample biofluid in one study each, while one study did not report any sample biofluid utilized [17].…”

“…, while 9 studies reported the duration of sample collection, i.e., 30 s [18,48,51], 1 min [50], 2 min [53], 4 min [52], and 5 to 10 min [19,20,23]. Varying methods were used to measure the total protein content of the sample biofluid including bicinchoninic acid (BCA) assay [48,50,51], micro-BCA (µBCA) [23], Bradford assay [49,52,53], and Lowry assay [17,[19][20][21][22] (Table 1).…”

“…Later, the same group [20] examined salivary biomarkers for oral tumors, emphasizing PTPN5 and p53. Similarly, Ploypetch et al [21] explored salivary biomarkers for monitoring therapeutic response in canine oral melanoma, discovering a potential prognostic biomarker. Recently in 2022, Ploypetch et al [22] investigated the composition of acquired enamel pellicle on canine teeth, revealing proteins involved in bacterial colonization.…”