MiR-9 is overexpressed in spontaneous canine osteosarcoma and promotes a metastatic phenotype including invasion and migration in osteoblasts and osteosarcoma cell lines.

BACKGROUND: MicroRNAs (miRNAs) regulate the expression of networks of genes and their dysregulation is well documented in human malignancies; however, limited information exists regarding the impact of miRNAs on the development and progression of osteosarcoma (OS). Canine OS exhibits clinical and molecular features that closely resemble the corresponding human disease and it is considered a well-established spontaneous animal model to study OS biology. The purpose of this study was to investigate miRNA dysregulation in canine OS. METHODS: We evaluated miRNA expression in primary canine OS tumors and normal canine osteoblast cells using the nanoString nCounter system. Quantitative PCR was used to validate the nanoString findings and to assess miR-9 expression in canine OS tumors, OS cell lines, and normal osteoblasts. Canine osteoblasts and OS cell lines were stably transduced with pre-miR-9 or anti-miR-9 lentiviral constructs to determine the consequences of miR-9 on cell proliferation, apoptosis, invasion and migration. Proteomic and gene expression profiling of normal canine osteoblasts with enforced miR-9 expression was performed using 2D-DIGE/tandem mass spectrometry and RNA sequencing and changes in protein and mRNA expression were validated with Western blotting and quantitative PCR. OS cell lines were transduced with gelsolin (GSN) shRNAs to investigate the impact of GSN knockdown on OS cell invasion. RESULTS: We identified a unique miRNA signature associated with primary canine OS and identified miR-9 as being significantly overexpressed in canine OS tumors and cell lines compared to normal osteoblasts. Additionally, high miR-9 expression was demonstrated in tumor-specific tissue obtained from primary OS tumors. In normal osteoblasts and OS cell lines transduced with miR-9 lentivirus, enhanced invasion and migration were observed, but miR-9 did not affect cell proliferation or apoptosis. Proteomic and transcriptional profiling of normal canine osteoblasts overexpressing miR-9 identified alterations in numerous genes, including upregulation of GSN, an actin filament-severing protein involved in cytoskeletal remodeling. Lastly, stable downregulation of miR-9 in OS cell lines reduced GSN expression with a concomitant decrease in cell invasion and migration; concordantly, cells transduced with GSN shRNA demonstrated decreased invasive properties. CONCLUSIONS: Our findings demonstrate that miR-9 promotes a metastatic phenotype in normal canine osteoblasts and malignant OS cell lines, and that this is mediated in part by enhanced GSN expression. As such, miR-9 represents a novel target for therapeutic intervention in OS.

Biologic activity of the novel small molecule STAT3 inhibitor LLL12 against canine osteosarcoma cell lines.

BACKGROUND: STAT3 [1] has been shown to be dysregulated in nearly every major cancer, including osteosarcoma (OS). Constitutive activation of STAT3, via aberrant phosphorylation, leads to proliferation, cell survival and resistance to apoptosis. The present study sought to characterize the biologic activity of a novel allosteric STAT3 inhibitor, LLL12, in canine OS cell lines. RESULTS: We evaluated the effects of LLL12 treatment on 4 canine OS cell lines and found that LLL12 inhibited proliferation, induced apoptosis, reduced STAT3 phosphorylation, and decreased the expression of several transcriptional targets of STAT3 in these cells. Lastly, LLL12 exhibited synergistic anti-proliferative activity with the chemotherapeutic doxorubicin in the OS lines. CONCLUSION: LLL12 exhibits biologic activity against canine OS cell lines through inhibition of STAT3 related cellular functions supporting its potential use as a novel therapy for OS.

Serological study of selected vector-borne diseases in shelter dogs in central Spain using point-of-care assays.

We evaluated the prevalence of selected vector-borne diseases in 131 dogs in an animal shelter in central Spain using point-of-care assays (SNAP 4DX and SNAP Leishmania; IDEXX Laboratories, Westbrook, ME). The SNAP 4DX detects Dirofilaria immitis (Di) antigen and antibodies against Ehrlichia canis (Ec), Borrelia burgdorferi (Bb), and Anaplasma phagocytophylum (Aph); the SNAP Leishmania kit detects antibodies against Leishmania infantum (Li). Dogs were classified as healthy or sick based on physical examination, complete blood counts, and serum chemistry profiles. The prevalence of positive test results was as follows: Ec, 5.3% (n = 7); Aph, 19.0% (n = 25); Bb, 0%; Di, 0%; and Li, 5.3% (n = 7). Four dogs (3%) were coexposed to Ec and Aph, and three dogs (2.3%) were coexposed to Aph and Li. There was no statistically significant correlation between positive serology and clinical status (sick vs. healthy) or hematologic/biochemical abnormalities. The prevalence of Aph was the highest and is in agreement with a recent report in a dog shelter in northwestern Spain. These point-of-care assays may be more valuable as epidemiologic than as clinical tools.