Publications by authors named "Bommireddy Ramireddy"

Liver cancer represents a substantial global health challenge, contributing significantly to worldwide morbidity and mortality. It has long been understood that tumors are not composed solely of cancerous cells, but also include a variety of normal cells within their structure. These tumor-associated normal cells encompass vascular endothelial cells, fibroblasts, and various inflammatory cells, including neutrophils, monocytes, macrophages, mast cells, eosinophils, and lymphocytes.

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Head and neck squamous cell carcinoma (HNSCC) is a spectrum of heterogeneous malignancies. A variety of genetic, environmental, and lifestyle factors contribute to the development of HNSCC. Carcinogenesis is a multistep process in which cell proliferation-associated oncogenes and cell-cycle regulation-associated tumor suppressor genes are dysregulated, resulting in premalignant lesions.

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Triple-negative breast cancer (TNBC) is an aggressive and highly metastatic type of tumor. TNBC is often enriched in tumor-infiltrating neutrophils (TINs), which support cancer growth in part by counteracting tumor-infiltrating lymphocytes (TILs). Prior studies identified the enhancer of zeste homolog 2 (EZH2) as a pro-tumor methyltransferase in primary and metastatic TNBCs.

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Article Synopsis
  • Current influenza vaccines work well for younger people but are less effective for the elderly due to age-related immune decline (immunosenescence).
  • Research on GPI-anchored cytokine-adjuvants combined with influenza hemagglutinin virus-like particles (HA-VLP) showed improved immune responses and reduced viral replication in aged mice compared to standard HA-VLP vaccines.
  • The study concludes that using cytokine-adjuvanted HA-VLP vaccines could potentially improve protection against influenza A virus for older adults, even without the presence of neutralizing antibodies.
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In the past decades, advances in the use of adoptive cellular therapy to treat cancer have led to unprecedented responses in patients with relapsed/refractory or late-stage malignancies. However, cellular exhaustion and senescence limit the efficacy of FDA-approved T-cell therapies in patients with hematologic malignancies and the widespread application of this approach in treating patients with solid tumors. Investigators are addressing the current obstacles by focusing on the manufacturing process of effector T cells, including engineering approaches and expansion strategies to regulate T-cell differentiation.

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Several approaches have produced an effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since millions of people are exposed to influenza virus and SARS-CoV-2, it is of great interest to develop a two-in-one vaccine that will be able to protect against infection of both viruses. We have developed a hybrid vaccine for SARS-CoV-2 and influenza viruses using influenza virus-like particles (VLP) incorporated by protein transfer with glycosylphosphatidylinositol (GPI)-anchored SARS-CoV-2 RBD fused to GM-CSF as an adjuvant.

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Background: PD-L1 is one of the major immune checkpoints which limits the effectiveness of antitumor immunity. Blockade of PD-L1/PD-1 has been a major improvement in the treatment of certain cancers, however, the response rate to checkpoint blockade remains low suggesting a need for new therapies. Metformin has emerged as a potential new drug for the treatment of cancer due to its effects on PD-L1 expression, T cell responses, and the immunosuppressive environment within tumors.

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Dendritic cells (DCs) are the most effective antigen presenting cells for the development of T cell responses. The only FDA approved DC-based immunotherapy to date is Sipuleucel-T, which utilizes a fusion protein to stimulate DCs ex vivo with GM-CSF and simultaneously deliver the antigen PAP for prostate cancer. This approach is restricted by the breadth of immunity elicited to a single antigen, and to cancers that have a defined tumor associated antigen.

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Imaging techniques based on fluorescence and bioluminescence have been important tools in visualizing tumor progression and studying the effect of drugs and immunotherapies on tumor immune microenvironment in animal models of cancer. However, transgenic expression of foreign proteins may induce immune responses in immunocompetent syngeneic tumor transplant models and augment the efficacy of experimental drugs. In this study, we show that the growth rate of Lewis lung carcinoma (LL/2) tumors was reduced after transduction of tdTomato and luciferase (tdTomato/Luc) compared to the parental cell line.

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Triple-negative breast cancer (TNBC) afflicts women at a younger age than other breast cancers and is associated with a worse clinical outcome. This poor clinical outcome is attributed to a lack of defined targets and patient-to-patient heterogeneity in target antigens and immune responses. To address such heterogeneity, we tested the efficacy of a personalized vaccination approach for the treatment of TNBC using the 4T1 murine TNBC model.

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Immune checkpoint inhibitor (ICI) immunotherapy improved the survival of head and neck squamous cell carcinoma (HNSCC) patients. However, more than 80% of the patients are still resistant to this therapy. To test whether the efficacy of ICI therapy can be improved by vaccine-induced immunity, we investigated the efficacy of a tumor membrane-based vaccine immunotherapy in murine models of HNSCC.

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The development of colorectal cancer in the azoxymethane-induced mouse model can be observed by using a miniaturized optical coherence tomography (OCT) imaging system. This system is uniquely capable of tracking disease development over time, allowing for the monitoring of morphological changes in the distal colon due to tumor development and the presence of lymphoid aggregates. By using genetically engineered mouse models deficient in Interleukin 6 (IL-6) and Smad family member 3 (Smad3), the role of inflammation on tumor development and the immune system can be elucidated.

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Optical coherence tomography (OCT) is a high-resolution, nondestructive imaging modality that enables time-serial assessment of adenoma development in the mouse model of colorectal cancer. In this study, OCT was utilized to evaluate the effectiveness of interventions with the experimental antitumor agent α-difluoromethylornithine (DFMO) and a nonsteroidal anti-inflammatory drug sulindac during early [chemoprevention (CP)] and late stages [chemotherapy (CT)] of colon tumorigenesis. Biological endpoints for drug interventions included OCT-generated tumor number and tumor burden.

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Calcineurin (CN) is a phosphatase that activates nuclear factor of activated T cells (NFAT). While the CN inhibitors cyclosporine A (CsA) and tacrolimus (FK506) can prevent graft rejection, they also cause inflammatory diseases. We investigated the role of calcineurin using mice deficient in the CN catalytic subunit Aβ (CNAβ).

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Transforming growth factor beta1 (TGFbeta1) is a multifunctional growth factor involved in wound healing, tissue fibrosis, and in the pathogenesis of many syndromic diseases (e.g., Marfan syndrome, Camurati-Engelmann disease) and muscular, neurological, ophthalmic, cardiovascular and immunological disorders, and cancer.

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Nonclassical MHC Class 1b antigens differ from classical MHC class 1a antigens in having a restricted polymorphism as well as varied surface expression in different cell types. They have been hypothesized to play a role in bridging adaptive and innate immune responses. We examined the effects of JEV infection on the expression of classical MHC class 1a and nonclassical MHC class 1b genes in five different cell lines.

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TGFbeta1 is considered to be required for peripheral maintenance of CD4(+)CD25(+)FOXP3(+) T(reg) cells. However, we demonstrate no reduction in the percentage of such T cells in the spleens and thymi of Tgfb1(-/-) mice. Although putative T(reg) cells, characterized as CD4(+)CD25(+)FOXP3(+)CD62L(+) T cells, are increased in Tgfb1(-/-) mice, they may be inadequate to control activated T cells since the ratio of activated T cells:putative T(reg) cells is several-fold higher in Tgfb1(-/-) mice than in control mice.

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Ample evidence suggests a role of TGF-beta in preventing autoimmunity. Multiorgan inflammatory disease, spontaneous activation of self-reactive T cells, and autoantibody production are hallmarks of autoimmune diseases, such as lupus. These features are reminiscent of the immunopathology manifest in TGF-beta1-deficient mice.

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Transforming growth factor beta1 (TGFbeta1), an important pleiotropic, immunoregulatory cytokine, uses distinct signaling mechanisms in lymphocytes to affect T-cell homeostasis, regulatory T (Treg)-cell and effector-cell function and tumorigenesis. Defects in TGFbeta1 expression or its signaling in T cells correlate with the onset of several autoimmune diseases. TGFbeta1 prevents abnormal T-cell activation through the modulation of Ca2+-calcineurin signaling in a Caenorhabditis elegans Sma and Drosophila Mad proteins (SMAD)3 and SMAD4-independent manner; however, in Treg cells, its effects are mediated, at least in part, through SMAD signaling.

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To investigate whether the multifocal inflammatory disease in TGFbeta1-deficient mice is caused by self-antigen (self-Ag)-specific autoreactive T cells, or whether it is caused by antigen independent, spontaneous hyperactivation of T cells, we have generated Tgfb1(-/-) and Tgfb1(-/-) Rag1(-/-) mice expressing the chicken OVA-specific TCR transgene (DO11.10). On a Rag1-sufficient background, Tgfb1(-/-) DO11.

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Transforming growth factor beta1 (TGFbeta1) is a potent negative immunoregulatory molecule. We have previously shown that the autoimmune-mediated weaning-age lethality of Tgfb1-/- mice is reversed upon genetic combination with Scid or Rag null alleles. Here, we show that elimination of T but not B cells is sufficient for the reversal, but elimination of either CD4+ or CD8+ cells is not.

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Recent studies by Chatenoud and co-workers suggest that non-mitogenic F(ab′) fragments of anti-CD3 antibodies, which cannot bind the Fc receptor, induce a prolonged period of tolerance and prevent diabetes in nonobese diabetic (NOD) mice. Tolerance is established by regulatory T cells through the production of transforming growth factor-β1 (TGF-β1), but the mechanism by which TGF-β1 confers this activity is unclear. Analysis of mice deficient in TGF-β1 suggests that TGF-β1 raises the threshold at which intracellular calcium activates T cells to a level that prevents an autoimmune response.

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TGF-beta1 plays an important role in the maintenance of immune homeostasis and self-tolerance. To determine the mechanism by which TGF-beta1 prevents autoimmunity we have analyzed T cell activation in splenic lymphocytes from TGF-beta1-deficient mice. Here we demonstrate that unlike wild-type splenic lymphocytes, those from Tgfb1(-/-) mice are hyporesponsive to receptor-mediated mitogenic stimulation, as evidenced by diminished proliferation and reduced IL-2 production.

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TGFbeta1 is a polypeptide growth modulatory and differentiation factor involved in many biological processes including immune homeostasis and self-tolerance. Tgfb1 knockout mice die around weaning age due to severe inflammation in most major organ systems, but the mechanism underlying this disease is not understood. In this study we demonstrate that Tgfb1(-/-) CD4(+)CD8(+) and CD4(+)CD8(-) thymocytes are hyperresponsive to receptor-mediated and receptor-independent mitogenic stimulation.

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