Publications by authors named "Olga Hrytsenko"

DPX is a novel delivery platform that generates targeted CD8  T cells and drives antigen-specific cytotoxic T cells into tumours. Cancer cells upregulate phosphatidylserine (PS) on the cell surface as a mechanism to induce an immunosuppressive microenvironment. Development of anti-PS targeting antibodies have highlighted the ability of a PS-blockade to enhance tumour control by T cells by releasing immunosuppression.

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Background: Future cancer immunotherapies will combine multiple treatments to generate functional immune responses to cancer antigens through synergistic, multi-modal mechanisms. In this study we explored the combination of three distinct immunotherapies: a class I restricted peptide-based cancer vaccine, metronomic cyclophosphamide (mCPA) and anti-PD-1 treatment in a murine tumor model expressing HPV16 E7 (C3).

Methods: Mice were implanted with C3 tumors subcutaneously.

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Tilapia, a teleost fish, have multiple large anatomically discrete islets which are easy to harvest, and when transplanted into diabetic murine recipients, provide normoglycemia and mammalian-like glucose tolerance profiles. Tilapia insulin differs structurally from human insulin which could preclude their use as islet donors for xenotransplantation. Therefore, we produced transgenic tilapia with islets expressing a humanized insulin gene.

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In clinical trials, metronomic cyclophosphamide (CPA) is increasingly being combined with vaccines to reduce tumor-induced immune suppression. Previous strategies to modulate the immune system during vaccination have involved continuous administration of low dose chemotherapy, studies that have posed unique considerations for clinical trial design. Here, we evaluated metronomic CPA in combination with a peptide vaccine targeting HPV16E7 in an HPV16-induced tumor model, focusing on the cytotoxic T-cell response and timing of low dose metronomic CPA (mCPA) treatment relative to vaccination.

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Facilitative glucose transporters (GLUTs) are responsible for passively transporting monosaccharides across the plasma membrane. We sequenced and characterized the Nile tilapia (Oreochromis niloticus) GLUT-1 (tGLUT-1) cDNA and genomic DNA. Using rapid amplification of the cDNA ends (RACE), two tGLUT-1 transcripts were detected differing in the length of the 3' untranslated region, 2851 and 4577 bp.

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Compared to mammals, little is known about insulin gene expression in fish. Using transient transfection experiments and mammalian insulinoma cell lines we demonstrate that transcription of the Nile tilapia (Oreochromis niloticus) insulin gene is (a) regulated in a beta-cell-specific manner; and (b) not sensitive to the glucose stimulations. Deletion analysis of the 1575 bp 5' insulin gene flanking sequence revealed that cooperative interactions between regulatory elements within the proximal (-1 to -396 bp) and the distal (-396 bp to -1575 bp) promoter regions were necessary for induction of the beta-cell-specific transcription.

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While the presence of immunoreactive insulin in the central nervous system of many vertebrate species is well known, the origin of brain insulin is still debated. In this study, we applied RT-PCR, quantitative RT-PCR (qRT-PCR), and Northern hybridization to examine expression of the insulin gene in different tissues of an adult teleost fish, the Nile Tilapia (Oreochromis niloticus). We found that the insulin gene is transcribed at a high level in Brockmann bodies (pancreatic islet organs) and at a low level in the brain and pituitary gland.

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Background: Tilapia are commercially important tropical fish which, like many teleosts, have anatomically discrete islet organs called Brockmann bodies. When transplanted into diabetic nude mice, tilapia islets provide long-term normoglycemia and mammalian-like glucose tolerance profiles.

Methods: Using site-directed mutagenesis and linker ligation we have "humanized" the tilapia insulin gene so that it codes for [desThrB30] human insulin while maintaining the tilapia regulatory sequences.

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