Prognostic phenotypic classification for canine mammary tumors

Mammary neoplasms are a heterogeneous form of disease, and in order to determine its course and biological features with more accuracy, investigations based on tumor phenotypes are required. The aim of the present study was to propose and validate a phenotypic classification for canine mammary tumors and to assess any association between clinicopathological characteristics, survival and prognosis. For the immunohistochemistry analysis, the primary antibodies against estrogen receptor-α, progesterone receptor, human epidermal growth factor receptor 2 (HER-2)/neu and E-cadherin were used. A total of 110 canine mammary tumors were investigated; 42 tumors were classified as luminal A, 41 as luminal B, 17 as triple-negative and 10 as HER-2-positive. The luminal A and B phenotypes were associated with improved prognosis, whereas HER-2positive and triple-negative tumors were more aggressive, and exhibited a significant association with the occurrence of metastasis, a worse Tumor-Node-Metastasis classification and shorter survival time (P<0.05). In addition, there were different levels of E-cadherin expression intensity observed among the four tumor profiles investigated. Luminal A and B phenotypes presented an upregulation of E-cadherin compared with the HER-2 positive and triple-negative phenotypes (P<0.05). From the results of the present study, the proposed immunohistochemical panel and phenotypic classification techniques could be useful diagnostic tools with a good technical applicability in veterinary oncology. The analysis of E-cadherin expression in the panel of tumor markers allowed a more accurate classification for determining the biological features of the mammary tumor.

Abstract B25: Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors

Introduction: The angiogenesis process is regulated by numerous factors, especially the hypoxia-inducible factor 1alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF). The HIF-1 is a central regulator of pathophysiologic response of cells to hypoxia conditions, able to activate transcription of the gene that promotes the induction of VEGF, which in turn promotes angiogenesis through its ability to stimulate growth, migration, and invasion of endothelial cells, leading to the formation of new blood vessels and subsequent tumor growth. Metformin has demonstrated its ability to reduce the incidence of cancer in diabetic patients with positive results, especially in breast cancer, inhibiting cell growth by AMPK/Akt/mTOR signaling pathway. Likewise, LY294002, a PI3K signaling pathway inhibitor, has antiangiogenic features. In this context, the aim of this study was to evaluate the effectiveness of metformin and LY294002 inhibitor treatment in angiogenesis as a therapeutic strategy in mammary tumors in an in vitro and in vivo study.

Materials and Methods: In the in vitro study, canine mammary tumor cell line (CF41) was cultured in DMEM high-glucose culture medium, at 37°C in 5% CO2. Cell viability was measured by MTT assay after treatment with different concentrations of metformin and LY294002 inhibitor. Once established the concentration of 5 mM for metformin and 5 µM of LY294002, the protein and gene expression of HIF-1alpha and VEGF were detected by immunocytochemistry and real-time PCR, respectively. For an in vivo study, CF41 were injected in nude athymic female mice and treated with metformin (200 mg/kg i.p.) for 4 weeks and LY294002 (7.5 mg/kg intratumorally) every 3 days for three times. At the end, mice were euthanized and the tumors were collected to determine the protein and gene expression of HIF-1alpha and VEGF and microvessel density by immunohistochemistry for CD31. The immunostaining was quantified by optical densitometry technique, slides were analyzed and photographed in Nikon Eclipse E200 microscope at 40X objective, and proteins were quantified by the ImageJ software analysis. For real-time PCR, the relative expression of the genes of interest was determined by DataAssist v3.0 software, using Ct method.

Results: There was a significant decrease of cell viability after treatment with different concentrations of metformin and LY294002 in 24 hours. Both HIF-1alpha and VEGFA protein and gene expression significantly decreased after treatment with metformin and LY294002 or in combination. Furthermore, in animals, there was a decrease in tumor size, protein and gene expression of HIF-1alpha and VEGFA, in addition to a decrease of CD31 expression after all treatments.

Conclusion: Our results suggest the potential effectiveness of metformin and LY294002 acting in angiogenesis process of mammary tumors.

Financial support: FAPESP.

Citation Format: Marina Gobbe Moschetta, Camila Leonel, Larissa Bazela Maschio-Signorini, Thaiz Ferraz Borin, Gabriela Bottaro Gelaleti, Lívia Carvalho Ferreira, Bruna Victorasso Jardim-Perassi, Nathália Martins Sonehara, Debora Aparecida Pires de Campos Zuccari. Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B25.

Efficacy of melatonin, IL-25 and siIL-17B in tumorigenesis-associated properties of breast cancer cell lines

Mammary tumorigenesis can be modulated by melatonin, which has oncostatic action mediated by multiple mechanisms, including the inhibition of the activity of transcription factors such as NF-κB and modulation of interleukins (ILs) expression. IL-25 is an active cytokine that induces apoptosis in tumor cells due to differential expression of its receptor (IL-17RB). IL-17B competes with IL-25 for binding to IL-17RB in tumor cells, promoting tumorigenesis. This study purpose is to address the possibility of engaging IL-25/IL-17RB signaling to enhance the effect of melatonin on breast cancer cells. Breast cancer cell lines were cultured monolayers and 3D structures and treated with melatonin, IL-25, siIL-17B, each alone or in combination. Cell viability, gene and protein expression of caspase-3, cleaved caspase-3 and VEGF-A were performed by qPCR and immunofluorescence. In addition, an apoptosis membrane array was performed in metastatic cells. Treatments with melatonin and IL-25 significantly reduced tumor cells viability at 1mM and 1ng/mL, respectively, but did not alter cell viability of a non-tumorigenic epithelial cell line (MCF-10A). All treatments, alone and combined, significantly increased cleaved caspase-3 in tumor cells grown as monolayers and 3D structures (p<0.05). Semi-quantitative analysis of apoptosis pathway proteins showed an increase of CYTO-C, DR6, IGFBP-3, IGFBP-5, IGFPB-6, IGF-1, IGF-1R, Livin, P21, P53, TNFRII, XIAP and hTRA proteins and reduction of caspase-3 (p<0.05) after melatonin treatment. All treatments reduced VEGF-A protein expression in tumor cells (p<0.05). Our results suggest therapeutic potential, with oncostatic effectiveness, pro-apoptotic and anti-angiogenic properties for melatonin and IL-25-driven signaling in breast cancer cells.

Melatonin and IL-25 modulate apoptosis and angiogenesis mediators in metastatic (CF-41) and non-metastatic (CMT-U229) canine mammary tumour cells

BACKGROUND

Melatonin has oncostatic actions and IL-25 is active in inflammatory processes that induce apoptosis in tumor cells AIM: The aim of this study was to evaluate melatonin and IL-25 in metastatic (CF-41) and non-metastatic (CMT-U229) canine mammary tumor cells cultured as monolayers and tridimensional structures.

MATERIALS AND METHODS

The cells were treated with melatonin, IL-25 and IL-17B silencing gene and performed cell viability, gene and protein expression of caspase-3 and VEGFA (Vascular endothelial growth factor A) and an apoptosis membrane protein array.

RESULTS

Treatment with 1 mM of melatonin reduced cell viability of both tumor cell lines, all treatments alone and combined significantly increased caspase-3 cleaved and proteins involved in the apoptotic pathway and reduced pro-angiogenic VEGFA, confirming the effectiveness of these potential promising treatments.

CONCLUSION

This is the first study evaluating the potential use of these strategies in CF-41 and CMT-U229 cell lines and together encourages subsequent in vitro and in vivo studies for further exploration of clinical applications.