Biology subjects

Guzik, H.

Publications and source records attributed to Guzik, H..

5 recordsLinked to original sources

bioRxiv2024

Intratumoral CXCL12 Gradients Contextualize Tumor Cell Invasion, Migration and Immune Suppression in Breast Cancer

Although the CXCL12/CXCR4 pathway has been prior investigated for its prometastatic and immuno- suppressive roles in the tumor microenvironment, evidence on the spatiotemporal regulation of these hallmarks has been lacking. Here, we demonstrate that CXCL12 forms a gradient specifically around cancer cell intravasation doorways, also known as Tumor Microenvironment of Metastasis (TMEM) doorways, thus facilitating the chemotactic translocation of prometastatic tumor cells expressing CXCR4 toward the perivascular TMEM doorways for subsequent entry into peripheral circulation. Fur- thermore, we demonstrate that the CXCL12-rich micro-environment around TMEM doorways may cre- ate immunosuppressive niches, whereby CD8+ T cells, despite being attracted to these regions, often exhibit reduced effector functions, limiting their efficacy. While the CXCL12/CXCR4 pathway can mini- mally influence the overall composition of immune cell populations, it biases the distribution of CD8+ T cells away from TMEM doorways, justifying its prior-established role as immunosuppressive factor for CD8+ T cells. Our research suggests that the complex interactions between CXCL12 and the various tumor and immune cell types contributes not only to the completion of the initial steps of the metastatic cascade, but also offers an immunological "sanctuary" to prometastatic tumor cells homed around TMEM doorways. Overall, our study enhances our current understanding on the mechanisms, via which CXCL12 orchestrates tumor cell behavior and immune dynamics, potentially guiding future thera- peutic strategies to combat breast cancer metastasis and improve anti-tumor immunity.

cancer biology↗

bioRxiv2024

Unlocking the Potential: FKK6 as a Microbial Mimicry Based Therapy for Chronic Inflammation-Associated Colorectal Cancer in a Murine Model

Chronic intestinal inflammation significantly contributes to the development of colorectal cancer (CRC) and remains a pertinent clinical challenge, necessitating novel therapeutic approaches. Indole-based microbial metabolite mimics FKK6, which is a ligand and agonist of the pregnane X receptor (PXR), was recently demonstrated to have PXR-dependent anti-inflammatory and protective effects in a mouse model of dextran sodium sulfate (DSS)-induced acute colitis. Here, we examined the therapeutic potential of FKK6 in a mouse model (C57BL/6 FVB humanized PXR mice) of colitis-associated colon cancer (CAC) induced by azoxymethane (AOM) and dextran sodium sulfate (DSS). FKK6 (2 mg/kg) displayed substantial anti-tumor activity, as revealed by reduced size and number of colon tumors, improved colon histopathology, and decreased expression of tumor markers (c-MYC, {beta}-catenin, Ki-67, cyclin D) in the colon. In addition, we carried out the chronic toxicity (30 days) assessment of FKK6 (1 mg/kg and 2 mg/kg) in C57BL/6 mice. Histological examination of tissues, biochemical blood analyses, and immunohistochemical staining for Ki-67 and {gamma}-H2AX showed no difference between FKK6-treated and control mice. Comparative metabolomic analyses in mice exposed for 5 days to DSS and administered with FKK6 (0.4 mg/kg) revealed no significant effects on several classes of metabolites in the mouse fecal metabolome. Ames and micronucleus tests showed no genotoxic and mutagenic potential of FKK6 in vitro. In conclusion, anticancer effects of FKK6 in AOM/DSS-induced CAC, together with FKK6 safety data from in vitro tests and in vivo chronic toxicity study, and comparative metabolomic study, are supportive of the potential therapeutic use of FKK6 in the treatment of CAC.

pharmacology and toxicology↗

bioRxiv2024

Morphometric Analysis of the Thymic Epithelial Cell (TEC) Network Using Integrated and Orthogonal Digital Pathology Approaches

The thymus, a central primary lymphoid organ of the immune system, plays a key role in T cell development. Surprisingly, the thymus is quite neglected with regards to standardized pathology approaches and practices for assessing structure and function. Most studies use multispectral flow cytometry to define the dynamic composition of the thymus at the cell population level, but they are limited by lack of contextual insight. This knowledge gap hinders our understanding of various thymic conditions and pathologies, particularly how they affect thymic architecture, and subsequently, immune competence. Here, we introduce a digital pathology pipeline to address these challenges. Our approach can be coupled to analytical algorithms and utilizes rationalized morphometric assessments of thymic tissue, ranging from tissue-wide down to microanatomical and ultrastructural levels. This pipeline enables the quantitative assessment of putative changes and adaptations of thymic structure to stimuli, offering valuable insights into the pathophysiology of thymic disorders. This versatile pipeline can be applied to a wide range of conditions that may directly or indirectly affect thymic structure, ranging from various cytotoxic stimuli inducing acute thymic involution to autoimmune diseases, such as myasthenia gravis. Here, we demonstrate applicability of the method in a mouse model of age-dependent thymic involution, both by confirming established knowledge, and by providing novel insights on intrathymic remodeling in the aged thymus. Our orthogonal pipeline, with its high versatility and depth of analysis, promises to be a valuable and practical toolset for both basic and translational immunology laboratories investigating thymic function and disease.

immunology↗

bioRxiv2022

TMEM106B is increased in Multiple Sclerosis plaques, and deletion causes accumulation of lipid after demyelination

During inflammatory, demyelinating diseases such as multiple sclerosis (MS) axonal damage is prevalent early in the disease course. Axonal damage includes swellings, defects in transport, and failure to clear damaged intracellular proteins, all of which affect recovery and compromise the integrity of neurons and remyelination. Autophagy and the clearance of damaged cell components by the proteasome are important for the maintenance of normal cellular turnover; and the restoration of cellular homeostasis. The gradual accumulation of insoluble proteins in the brain is known to impair recovery from several neurodegenerative diseases. In this study, we used mass spectrometry to identify insoluble proteins within high-speed, mercaptoethanol/sarcosyl-insoluble pellets from purified white matter plaques isolated from the brains of individuals with MS. We determined that insoluble transmembrane protein106B (TMEM106B), expressed in neurons and glia and normally lysosomal-associated, is increased in MS plaques relative to normal-appearing white matter from individuals with Alzheimers disease and non-neurologic controls. We found that decreased TMEM106B protein in mice results in significant axonal damage and lipid droplet accumulation in the spinal cord following chronic myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. When TMEM106Bt/t mice were treated with cuprizone to experimentally induce demyelination, a significant increase in lipid deposition was observed in the corpus callosum of TMEM106Bt/t mice post-cuprizone withdrawal. Our study shows that the brain and spinal cord from challenged TMEM106Bt/t mice accumulate OilRedO+/Perilipin2+ lipid droplets. We postulate that increased insolubility of TMEM106B in MS plaques limits debris clearance by the lysosome which over time contributes to failed remyelination and axonal defects. Abbreviated AbstractTransmembrane protein106B (TMEM106B), a lysosome-associated protein, is significantly less soluble in multiple sclerosis plaques than in white matter controls. Decreased TMEM106B produces significant axonal damage and lipid accumulation in mouse models of demyelinating diseases. TMEM106B insolubility and likely loss of function may limit lysosome transport and contribute to CNS pathology.

neuroscience↗

bioRxiv2021

Reovirus sensitizes microsatellite stable colorectal cancer to anti-PD-1 treatment via cross-talk in innate and adaptive immune systems

BackgroundMicrosatellite stable (MSS) colorectal cancer (CRC) represents ~85% of all CRCs. These tumors are poorly immunogenic and largely resistant to immunotherapy, necessitating a need to develop new immune enhancing strategies. Oncolytic reovirus has a high propensity to replicate in KRAS mutant tumors which account for ~50% of MSS CRCs. Current study explores the ability of reovirus to potentiate the effect of immune checkpoint inhibition in MSS CRC. MethodsEffectiveness of reovirus infection was quantified through MTT assay for cell viability, and expression of immune-response genes by flow cytometry, RT-qPCR, and microarray. Computational analysis of differentially expressed genes was performed by TAC, DAVID and STRING. Combinatorial approach using anti-PD-1 monoclonal antibody was assessed in ex vivo and in vivo models. Live-cell imaging, tumor volume and survival were measured for quantification of anti-tumor activity. Expression of pattern recognition receptors (PRRs), cell surface and activation markers of immune cells, and PD-1/PD-L1 axis were studied using multi-color flow cytometry, immunoblotting, immunohistochemistry, and immunofluorescence. ResultsReovirus infection exerted growth arrest and expression of immune-response genes in CRCs cell lines in a KRAS-dependent manner. However, microsatellite instability, rather than KRAS status determined immune-repose pathways, functionalities and biological processes post-reovirus infection. Furthermore, reovirus significantly enhanced the anti-tumor activity of anti-human PD-1 [nivolumab] treatment in MSS CRC cell lines ex vivo. Similarly, reovirus increased the activity of anti-mouse PD-1 treatment in the CT26 [MSS, KRASMut], but not the MC38 [MSI, KRASWt] syngeneic mouse model of CRC. Combinatorial treatment has reduced the proliferative index, increased apoptosis and differentially altered PD-L1/PD-1 signaling among CT26 and MC38 tumors. Activation of innate immune system and expression of PRRs and antigen presentation markers were observed under reovirus and anti-PD-1 treatment that additionally reduced immunosuppressive macrophages. This led to an increase in T cell subsets, increase in effector T cell activation, and decrease in exhaustion markers specifically within CT26 microenvironment. ConclusionThe current study systematically evaluates immune characteristics and immune microenvironment of CRC under reovirus/anti-PD-1 combination treatment that proves increased effectiveness among MSS compared to MSI CRCs. This is a promising regimen warranting translation into clinical trials. One Sentence SummaryOncolytic reovirus alters innate and adaptive immune system and potentiates MSS type colorectal cancer to checkpoint inhibition therapy.

cancer biology↗