Molecular signalling pathways in canine gliomas

Abstract

In this study, we determined the expression of key signalling pathway proteins TP53, MDM2, P21, AKT, PTEN, RB1, P16, MTOR and MAPK in canine gliomas using western blotting. Protein expression was defined in three canine astrocytic glioma cell lines treated with CCNU, temozolamide or CPT-11 and was further evaluated in 22 spontaneous gliomas including high and low grade astrocytomas, high grade oligodendrogliomas and mixed oligoastrocytomas. Response to chemotherapeutic agents and cell survival were similar to that reported in human glioma cell lines. Alterations in expression of key human gliomagenesis pathway proteins were common in canine glioma tumour samples and segregated between oligodendroglial and astrocytic tumour types for some pathways. Both similarities and differences in protein expression were defined for canine gliomas compared to those reported in human tumour counterparts. The findings may inform more defined assessment of specific signalling pathways for targeted therapy of canine gliomas.

Evaluation of P16 expression in canine appendicular osteosarcoma

“…No evidence of P16 protein expression was observed in negative control lanes 4–6 representing a different canine GBM (G4), a canine high grade oligodendroglioma (O5), and normal canine cerebrum (NB). These results were consistent with previous results using a different P16 antibody [24].

Fig.

…”

“…Control human and canine tissues were obtained from cell culture, surgical biopsy or necropsy as previously described [24]. Tissues know to express P16 (positive controls) included the SAOS2 human osteosarcoma cell line, a canine high grade oligodendroglioma (O8) and a canine grade IV astrocytoma/glioblastoma (GBM, G2); canine tissues previously demonstrated to not express P16 (negative controls) included a different canine GBM (G4), a high grade oligodendroglioma (O5) and normal canine cerebrum (NB) [24].…”

“…In order to test this hypothesis, the identification of a P16 antibody that reliably binds canine P16 protein in immunoblot and immunohistochemistry (IHC) assays was needed. Utilizing a set of control human and canine tissues with known P16 expression patterns [24], we identified an anti-P16 antibody with appropriate binding affinity in both immunoblot and IHC assays. In addition, we developed a set of canine tissue microarrays comprised of retrospective case material from 33 dogs with appendicular OSA with known treatment regimens and long-term outcomes.…”

Maximizing Local Access to Therapeutic Deliveries in Glioblastoma. Part V: Clinically Relevant Model for Testing New Therapeutic Approaches

“…These analyses have led to evolutions in the classification and prognostic stratification of human brain tumors, and are fundamental to the rational translational application of molecularly targeted therapies (38)(39)(40). The characterization of the molecular and genomic landscapes of canine brain tumors has been facilitated by the increasing availability of canine-specific reagents and advancements in high-throughput sequencing platforms (25).…”

“…The characterization of the molecular and genomic landscapes of canine brain tumors has been facilitated by the increasing availability of canine-specific reagents and advancements in high-throughput sequencing platforms (25). To date, studies in dogs have demonstrated that hallmark alterations in proteins involved in cellular proliferation, apoptosis, and cell-cycle regulation, such as the RTK, p53, and RB1 pathways that participate in tumorigenesis, parallel those seen in human gliomas (31,38,(40)(41)(42). Also similar to humans, overexpression of alpha3-beta1integrin, c-Met, EGFR, EphA2, IGFBP2, IL-13RA2, MMP-2, and-9, PDGFRa, uPAR, and VEGF/VEGFR1/2 have been observed in canine gliomas (43)(44)(45)(46)(47)(48)(49)(50)(51).…”