Comparative analysis of the surface exposed proteome of two canine osteosarcoma cell lines and normal canine osteoblasts

BACKGROUND: Osteosarcoma (OSA) is the most common primary bone tumor of dogs and carries a poor prognosis despite aggressive treatment. An improved understanding of the biology of OSA is critically needed to allow for development of novel diagnostic, prognostic, and therapeutic tools. The surface-exposed proteome (SEP) of a cancerous cell includes a multifarious array of proteins critical to cellular processes such as proliferation, migration, adhesion, and inter-cellular communication. The specific aim of this study was to define a SEP profile of two validated canine OSA cell lines and a normal canine osteoblast cell line utilizing a biotinylation/streptavidin system to selectively label, purify, and identify surface-exposed proteins by mass spectrometry (MS) analysis. Additionally, we sought to validate a subset of our MS-based observations via quantitative real-time PCR, Western blot and semi-quantitative immunocytochemistry. Our hypothesis was that MS would detect differences in the SEP composition between the OSA and the normal osteoblast cells. RESULTS: Shotgun MS identified 133 putative surface proteins when output from all samples were combined, with good consistency between biological replicates. Eleven of the MS-detected proteins underwent analysis of gene expression by PCR, all of which were actively transcribed, but varied in expression level. Western blot of whole cell lysates from all three cell lines was effective for Thrombospondin-1, CYR61 and CD44, and indicated that all three proteins were present in each cell line. Semi-quantitative immunofluorescence indicated that CD44 was expressed at much higher levels on the surface of the OSA than the normal osteoblast cell lines. CONCLUSIONS: The results of the present study identified numerous differences, and similarities, in the SEP of canine OSA cell lines and normal canine osteoblasts. The PCR, Western blot, and immunocytochemistry results, for the subset of proteins evaluated, were generally supportive of the mass spectrometry data. These methods may be applied to other cell lines, or other biological materials, to highlight unique and previously unrecognized differences between samples. While this study yielded data that may prove useful for OSA researchers and clinicians, further refinements of the described techniques are expected to yield greater accuracy and produce a more thorough SEP analysis

Pedicle ties provide a rapid and safe method for feline ovariohysterectomy

OBJECTIVES: The specific objectives of the present study were to 1) evaluate the rate of hemorrhage-related complications across a large number of feline pedicle tie procedures and 2) evaluate for a difference in surgical time between traditional pedicle double-ligation and pedicle tie procedures. METHODS: In the initial phase of the study 2136 intact female cats underwent an ovariohysterectomy using the pedicle tie technique. Hemorrhagic complications not detected intra-operatively were to be confirmed via exploratory surgery or necropsy. The second phase of the study recorded the duration of surgery for 4 groups: kittens undergoing pedicle ties (n=50), kittens undergoing pedicle double ligation (n=49), adult cats undergoing pedicle ties (n=50), and adult cats undergoing pedicle double ligation (n=54). Kittens were defined as a cat 4 months old or younger. Statistical comparisons of age, body weight, and surgical times between the pedicle tie and pedicle double ligation groups were performed within, but not between, kitten and adult cat categories. RESULTS: Six of 2136 cats (0.281%) experienced a hemorrhage-related complication associated with the ovarian pedicle. Five of the 6 ovarian pedicle hemorrhage-related complications were recognized and corrected intra-operatively, with the remaining hemorrhagic event being detected post-operatively. Surgical times were significantly shorter in pedicle tie kittens compared to pedicle double ligature kittens (4.7 ± 0.1 minutes and 6.7 ± 0.1 minutes, respectively) and pedicle tie adult cats compared to pedicle double ligature adult cats (5.0 ± 0.2 minutes and 7.0 ± 0.2 minutes, respectively). CONCLUSIONS AND RELEVANCE: The present study demonstrates that the pedicle tie technique is associated with a very low risk for hemorrhage-related complications and is significantly faster than double ligating the ovarian pedicle in both kittens and adult cats. Use of the pedicle tie technique has the potential to be of significant economic benefit in institutions that are performing large numbers of feline ovariohysterectomies

Antiproliferative effects of masitinib and imatinib against canine oral fibrosarcoma in vitro

Background: Canine oral fibrosarcoma (COF) is one of the most common oral tumors in dogs and carries a guarded prognosis due to a lack of effective systemic therapeutic options. Mastinib and imatinib are two commonly used tyrosine kinase inhibitors (TKIs) in veterinary oncology but their potential efficacy against COF is uncharacterized. To begin investigating the rationale for use of these TKIs against COF, the present study tested for the presence TKI targets PDGFR-α, PDGFR-β, Kit, and VEGFR-2 and examined the in vitro effects on cell viability after TKI treatment alone or with doxorubicin. Immunohistochemistry for PDGFR-α, PDGFR-β, Kit, and VEGFR-2 was performed in 6 COF tumor biopsies. Presence of these same receptors within 2 COF cell lines was probed by reverse transcription-polymerase chain reaction and, for those with mRNA detected, confirmed via western blot. Effects on cell viability were assessed using an MTS assay after masitinib or imatinib treatment alone (0-100 μM), or in combination with doxorubicin (0-3000 nM doxorubicin). Anti-PDGFRB siRNA knockdown was performed and the effect on cell viability quantified. Results: Expression of the TKI targets evaluated was similar between the 2 COF cell lines and the 6 COF tumor biopsies: PDGFR-α and PDGFR-β were detected in neoplastic cells from most COF tumor biopsies (5/6 and 6/6, respectively) and were present in both COF cell lines; KIT and KDR were not detected in any sample. Masitinib and imatinib IC50 values ranged from 7.9–33.4 μM, depending on the specific TKI and cell line tested. The addition of doxorubicin resulted in synergistic cytotoxicity with both TKIs. Anti-PDGFRB siRNA transfection reduced PDGFR-β protein expression by 77 % and 67 % and reduced cell viability by 24 % (p < 0.0001) and 28 % (0 = 0.0003) in the two cell lines, respectively. Conclusions: These results provide rationale for further investigation into the use of TKIs, possibly in combination with doxorubicin, as treatment options for COF.Keywords: Masitinib, Oral fibrosarcoma, Imatinib, Platelet-derived growth factor receptor, Do

A Multiplex Biomarker Approach for the Diagnosis of Transitional Cell Carcinoma from Canine Urine

Transitional cell carcinoma (TCC), the most common cancer of the urinary bladder in dogs, is usually diagnosed at an advanced disease stage with limited response to chemotherapy. Commercial screening tests lack specificity and current diagnostic procedures are invasive. A proof of concept pilot project for analyzing the canine urinary proteome as a non-invasive diagnostic tool for TCC identification was conducted. Urine was collected from 12 dogs in three cohorts (healthy, urinary tract infection, TCC) and analyzed using liquid chromatography tandem mass spectrometry. The presence of four proteins (macrophage capping protein, peroxiredoxin 5, heterogeneous nuclear ribonucleoproteins A2/B, and apolipoprotein A1) was confirmed via immunoblot. Of the total 379 proteins identified, 96 were unique to the TCC group. A statistical model, designed to evaluate the accuracy of this multiplex biomarker approach for diagnosis of TCC, predicted the presence of disease with 90% accuracy.Keywords: Liquid chromatography, Biomarkers, Tandem mass spectrometry, Canine, Transitional cell carcinom

Naphthalocyanine-Based Biodegradable Polymeric Nanoparticles for Image-Guided Combinatorial Phototherapy

Image-guided phototherapy is extensively considered as a promising therapy for cancer treatment. To enhance translational potential of this modality, we developed a single agent-based biocompatible nanoplatform that provides both real time near-infrared (NIR) fluorescence imaging and combinatorial phototherapy with dual photothermal and photodynamic therapeutic mechanisms. The developed theranostic nanoplatform consists of two building blocks: (1) silicon naphthalocyanine (SiNc) as NIR fluorescence imaging and phototherapeutic agent and (2) a copolymer, poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) as the biodegradable SiNc carrier. Our simple, highly reproducible and robust approach results in preparation of spherical, monodisperse SiNc-loaded PEG-PCL polymeric nanoparticles (SiNc-PNP) with a hydrodynamic size of 37.66 ± 0.26 nm (polydispersity index = 0.06) and surface charge of -2.76 ± 1.83 mV. The SiNc-loaded nanoparticles exhibit a strong NIR light absorption with an extinction coefficient of 2.8 x 10⁵ M⁻¹cm⁻¹ and efficiently convert the absorbed energy into fluorescence emission (Φ[subscript F] = 11.8%), heat (ΔT ~ 25 °C) and reactive oxygen species. Moreover, the SiNc-PNP are characterized by superior photostability under extensive photoirradiation and structure integrity during storage at room temperature over a period of 30 days. Following intravenous injection, the SiNc-PNP accumulated selectively in tumors and provided high lesion-to-normal tissue contrast for sensitive fluorescence detection. Finally, Adriamycin-resistant tumors treated with a single intravenous dose of SiNc-PNP (1.5 mg/kg) combined with 10 min of a 785 nm light irradiation (1.3 W/cm²) were completely eradicated from the mice without cancer recurrence or side effects. The reported characteristics make the developed SiNc-PNP a promising platform for future clinical application.This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society and can be found at: https://doi.org/10.1021/acs.chemmater.5b0312

Canine CT sternal lymph node data

<p>Canine sternal lymph node CT appearance data annotated to patient disease data</p

Metastasis of a Prostatic Carcinoma along an Omental Graft in a Dog

An 11-year-old male American Bulldog was presented for hematuria and tenesmus. It had been treated for chronic bacterial prostatitis with abscessation two years earlier and underwent castration and a prostatic omentalization procedure. There was no histologic evidence of prostatic neoplasia at that time. On physical examination, an enlarged prostate was found by rectal palpation, and it was characterized with ultrasonography and computed tomography. Surgical biopsies were obtained, and histopathology identified prostatic adenocarcinoma. It received carprofen and mitoxantrone chemotherapy in addition to palliative radiation therapy; it was euthanized six weeks later due to a progression of clinical signs. Necropsy findings included marked localized expansion of the prostatic tumor and dissemination of prostatic carcinoma cells throughout the peritoneal cavity along the omental graft with infiltration onto the serosal surfaces of most abdominal viscera and fat. This case represents a previously unreported potential complication of the omentalization procedure wherein carcinoma cells from a prostatic tumor that independently arose after omentalization may have metastasized along the surgically created omental graft