Molecular insights into traditional and innovative therapies for canine and human cancer

Cancer is a health concern for both the human and canine species. In this panorama, comparative oncology aims to address common questions by leveraging progress made in both species to reduce time and effort. Indeed, dogs represent a valuable model for several human malignancies, sharing clinical, pathological, immunological, environmental, and genomic characteristics. From this comparison, new insights into tumor biology and potential therapeutic approaches can emerge. In a context in which chemoresistance is a concerning problem and precision oncology becomes a mandatory choice, the design and development of new synthetic or natural compounds with anti-cancer properties could take great advantage of this mutual inter-species communication. The avenue of high-throughput technologies helps to investigate cancer biology more deeply and identify new therapeutic targets, thanks to genomics, transcriptomics, epigenomics, and proteomics. In this thesis, pairing RNA-sequencing (RNA-seq) with cellular and molecular biology techniques, the effects of conventional, targeted, natural-derived therapies in different canine tumor types were investigated. The whole transcriptomic effects of radiotherapy (RT) were evaluated in vivo in canine oral melanoma, while PARPi (Olaparib) and an extract derived from the red alga Sphaerococcus coronopifolius were tested in vitro in canine lymphoma/leukemia and mastocytoma, respectively. RNA-seq helps identify possible pathways associated with overall survival in canine oral melanoma, beyond highlighting the systemic and local effects of RT on the immune system, glycosylation, cell adhesion, and cell cycle. Moreover, it shows alternative cell death mechanisms (i.e., apoptosis vs pyroptosis) and the potential contribution of p53 SNVs in Olaparib mechanism of action and chemoresistance in hematological malignancies; additionally, transcriptomic investigations highlight the main involvement of mevalonate pathways in Sphaerococcus coronopifolius anti-cancer activity on mastocytoma-derived cells. Being aware that cancer phenotype is not defined just by the genome and transcriptome, in the fourth chapter, a wider multi-omics approach was applied to an EMT-induced human mammary adenocarcinoma cell model. RNA-seq, Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq), and Cleavage Under Targets and Tagmentation (CUT&Tag) were performed on the BT-474 cell line to define the role of vimentin and lamin B1 in the regulation of epithelial plasticity. Intermediate filaments could be considered hard-to-target proteins, and in recent years, their involvement in biological processes, different from their traditional structural function, has become more evident. Particularly, in the present study, their role in the nuclear compartment, in the DNA-binding, and in transcriptional and chromatin remodeling activity was investigated. Overall, in this thesis, new insights into human and canine oncology were obtained thanks to the application of -omics techniques. The effects of conventional, targeted, or natural-derived therapies and the biological role of hard-to-target proteins were explored to help define new therapeutic strategies. These could be considered as preliminary, but mandatory steps to address common questions in both species and clarify the direction of next efforts from both sides.