Lack of class I H-2 antigens in cells transformed by radiation leukemia virus is associated with methylation and rearrangement of H-2 DNA

Transformation of murine thymocytes by radiation leukemia virus is associated with reduced expression of the class I antigens encoded in the major histocompatibility complex (MHC) and increased methylation and altered restriction enzyme patterns of MHC DNA. These changes may play a role in host susceptibility to virus-induced leukemogenesis and accord with the notion that viral genomes play a regulatory function when they integrate adjacent to histocompatibiity genes

Interaction of human laminin receptor with Sup35, the [PSI⁺] prion-forming protein from S. cerevisiae: a yeast model for studies of LamR interactions with amyloidogenic proteins.

The laminin receptor (LamR) is a cell surface receptor for extracellular matrix laminin, whereas the same protein within the cell interacts with ribosomes, nuclear proteins and cytoskeletal fibers. LamR has been shown to be a receptor for several bacteria and viruses. Furthermore, LamR interacts with both cellular and infectious forms of the prion protein, PrP(C) and PrP(Sc). Indeed, LamR is a receptor for PrP(C). Whether LamR interacts with PrP(Sc) exclusively in a capacity of the PrP receptor, or LamR specifically recognizes prion determinants of PrP(Sc), is unclear. In order to explore whether LamR has a propensity to interact with prions and amyloids, we examined LamR interaction with the yeast prion-forming protein, Sup35. Sup35 is a translation termination factor with no homology or functional relationship to PrP. Plasmids expressing LamR or LamR fused with the green fluorescent protein (GFP) were transformed into yeast strain variants differing by the presence or absence of the prion conformation of Sup35, respectively [PSI⁺] and [psi⁻]. Analyses by immunoprecipitation, centrifugal fractionation and fluorescent microscopy reveal interaction between LamR and Sup35 in [PSI⁺] strains. The presence of [PSI⁺] promotes LamR co-precipitation with Sup35 as well as LamR aggregation. In [PSI⁺] cells, LamR tagged with GFP or mCherry forms bright fluorescent aggregates that co-localize with visible [PSI⁺] foci. The yeast prion model will facilitate studying the interaction of LamR with amyloidogenic prions in a safe and easily manipulated system that may lead to a better understanding and treatment of amyloid diseases

Sindbis Virus Vaccine Platform: A Promising Oncolytic Virus-Mediated Approach for Ovarian Cancer Treatment

This review article provides a comprehensive overview of a novel Sindbis virus vaccine platform as potential immunotherapy for ovarian cancer patients. Ovarian cancer is the most lethal of all gynecological malignancies. The majority of high-grade serous ovarian cancer (HGSOC) patients are diagnosed with advanced disease. Current treatment options are very aggressive and limited, resulting in tumor recurrences and 50–60% patient mortality within 5 years. The unique properties of armed oncolytic Sindbis virus vectors (SV) in vivo have garnered significant interest in recent years to potently target and treat ovarian cancer. We discuss the molecular biology of Sindbis virus, its mechanisms of action against ovarian cancer cells, preclinical in vivo studies, and future perspectives. The potential of Sindbis virus-based therapies for ovarian cancer treatment holds great promise and warrants further investigation. Investigations using other oncolytic viruses in preclinical studies and clinical trials are also presented

LamR co-localizes with visible Sup35 prion aggregates in yeast cells.

<p>pSUP35-GFP and pLamR-mCherry were co-expressed in weak [<i>PSI⁺</i>][<i>pin</i>⁻] and [<i>psi</i>⁻][<i>PIN⁺</i>] cells. Panels show GFP and mCherry fluorescence and their merged images. Brightfield (BF) images of the cells are shown in the far right panel. Two sets of images (A and B) are shown from independent transformants. Images were taken using a100× oil immersion lens. The images were visualized and merged using Adobe photoshop CS4.</p

Immunofluorescence of LamR-GFP and Sup35-GFP fusion proteins reveals aggregation of LamR in [<i>PSI</i>⁺] cells.

<p>Late-log cultures of (A) [<i>PSI⁺</i>][<i>PIN⁺</i>], (B) [<i>PSI⁺</i>][<i>pin</i>⁻], (C) [<i>psi</i>⁻][<i>PIN⁺</i>] and (D) [<i>psi</i>⁻ ][<i>pin</i>⁻] were examined with 100× oil immersion lens of a fluorescent microscope using a 488_ex, 507_em filter. Representative images from two independent transformants of each yeast strain are displayed.</p

Potent and Targeted Sindbis Virus Platform for Immunotherapy of Ovarian Cancer

Our laboratory has been developing a Sindbis viral (SV) vector platform for treatments of ovarian and other types of cancers. In this study we show that SV.IL-12 combined with an agonistic OX40 antibody can eliminate ovarian cancer in a Mouse Ovarian Surface Epithelial Cell Line (MOSEC) model and further prevent tumors in mice rechallenged with tumor cells after approximately 5 months. Treatment efficacy is shown to be dependent upon T-cells that are transcriptionally and metabolically reprogramed. An influx of immune cells to the tumor microenvironment occurs. Combination of sequences encoding both IL-12 and anti-OX40 into a single SV vector, SV.IgGOX40.IL-12, facilitates the local delivery of immunoregulatory agents to tumors enhancing the anti-tumor response. We promote SV.IgGOX40.IL-12 as a safe and effective therapy for multiple types of cancer

Human LamR is expressed in yeast cells.

<p>A. LamR protein (right panel) or LamR-GFP fusion (left panel) expressed in the [<i>PSI</i>⁺][<i>PIN⁺</i>] yeast prion strain grown in synthetic media either supplemented with 25 µM CuSO₄ (right panel and lane 2 of left panel) or containing no excess copper (lane1 of left panel). B. Expression of GPF (27 kDa), and LamR-GFP and Sup35-GFP fusion proteins (64 kDa and 104 kDa, respectively) in [<i>psi</i>⁻][<i>PIN⁺</i>] (−) and [<i>PSI⁺</i>][<i>PIN⁺</i>] (+) yeast strains. Anti-LamR (A) and anti-GFP (B) antibodies were used to detect LamR expression in yeast lysates (25 ug). Numbers in the middle (A) and right (B) refer to protein size markers (kDa). Similar expression levels were observed in [<i>pin</i>⁻] strains (not shown).</p

Centrifugation assay demonstrates aggregation of exogenous human LamR in the presence of the [<i>PSI</i>⁺] prion.

<p>(A) Total lysate (T), supernatant (S), and resuspended pellet (P) (20 µg per sample) of pCUP1-LamR::GFP and pCUP1-LamR transformants of yeast [<i>psi</i>⁻][<i>pin</i>⁻] and [<i>PSI⁺</i>][<i>PIN⁺</i>] strains were analyzed by western blot using the indicated antibodies. pCUP1-GFP was expressed in the [<i>PSI</i>⁺] strain as a control (bottom panel), and anti-yeast hexokinase antibody (anti-HK) was used to ensure pellets were free of cytoplasmic proteins (fifth panel from top). Shown are representative experiments out of 3 independent experiments. (B) Corresponding densitometric quantitation of percent distribution between supernatant and pellet fractions was determined from three independent experiments. Bars show standard error of the mean.</p