Biology subjects

Lotze, M. T.

Publications and source records attributed to Lotze, M. T..

4 recordsLinked to original sources

bioRxiv2026

Tumor-to-endothelium mitochondrial transfer licenses endothelial cells for CD8+ T cell recognition via mitochondrial neoantigen presentation

Renal cell carcinoma (RCC) frequently exhibits resistance to immune checkpoint blockade, highlighting the need for strategies that enhance tumor-specific T cell priming and improve immune access to the tumor microenvironment. Here we show that vaccination targeting tumor-associated mitochondrial antigens (TAMAs), derived from tumor-specific mitochondrial DNA (mtDNA) missense mutations, synergizes with PD-1/PD-L1 blockade to overcome checkpoint refractoriness in the RENCA RCC model. TAMAs vaccination elicits antigen-specific T cell responses, increases intratumoral CD8+ T cell infiltration, and reduces immunosuppressive myeloid populations, resulting in delayed tumor progression and improved survival when combined with checkpoint inhibition. In parallel, TAMAs + checkpoint blockade induces vascular remodeling characterized by increased pericyte coverage, reduced vascular leakage, improved perfusion and reduced hypoxia. Mechanistically, vascular remodeling is driven by CD8+ T cell-dependent, IFN{gamma}-associated immune activity and is associated with endothelial apoptosis and diminished intratumoral CD31 signal. We further identify tumor-to-endothelium mitochondrial transfer as a mechanism linking mitochondrial neoantigens to the tumor vascular compartment: tumor-derived mitochondria enter human and mouse endothelial cells in vitro and in vivo, and tumor-associated mtDNA mutations are detectable in endothelial fractions from murine tumors and human RCC specimens. Human endothelial cells can present mitochondrial neoantigens via MHC class I and become targets of TAMAs-specific CD8+ T cell cytotoxicity, including following mitochondrial acquisition from tumor cells. Together, these findings establish mitochondrial neoantigen immunity as a tractable approach to enhance checkpoint responses and reveal mitochondrial transfer as an antigenic bridge that expands immune targeting to the tumor vasculature.

cancer biology↗

bioRxiv2024

Systemic and local chronic inflammation and hormone disposition promote a tumor-permissive environment for breast cancer in older women

Estrogen receptor positive (ER+) breast cancer is the most common subtype of breast cancer and is an age-related disease. The peak incidence of diagnosis occurs around age 70, even though these post-menopausal patients have low circulating levels of estradiol (E2). Despite the hormone sensitivity of age-related tumors, we have a limited understanding of the interplay between systemic and local hormones, chronic inflammation, and immune changes that contribute to the growth and development of these tumors. Here, we show that aged F344 rats treated with the dimethylbenz(a)anthracene / medroxyprogestrone acetate (DMBA/MPA) carcinogen develop more tumors at faster rates than their younger counterparts, suggesting that the aged environment promotes tumor initiation and impacts growth. Single-nuclei RNA-seq (snRNA-seq) of the tumors showed broad local immune dysfunction that was associated with circulating chronic inflammation. Across a broad cohort of specimens from patients with ER+ breast cancer and age-matched donors of normal breast tissue, we observe that even with an estrone (E1)-predominant estrogen disposition in the systemic circulation, tumors in older patients increase HSD17B7 expression to convert E1 to E2 in the tumor microenvironment (TME) and have local E2 levels similar to pre-menopausal patients. Concurrently, trackable increases in several chemokines, defined most notably by CCL2, promote a chronically inflamed but immune dysfunctional TME. This unique milieu in the aged TME, characterized by high local E2 and chemokine-enriched chronic inflammation, promotes both accumulation of tumor-associated macrophages (TAMs), which serve as signaling hubs, as well as polarization of TAMs towards a CD206+/PD-L1+, immunosuppressive phenotype. Pharmacologic targeting of estrogen signaling (either by HSD17B7 inhibition or with fulvestrant) and chemokine inflammation both decrease local E2 and prevent macrophage polarization. Overall, these findings suggest that chronic inflammation and hormonal disposition are critical contributors to the age-related nature of ER+ breast cancer development and growth and offer potential therapeutic insight to treat these patients. Translational SummaryWe uncover the unique underpinnings establishing how the systemic host environment contributes to the aged breast tumor microenvironment, characterized by high local estradiol and chronic inflammation with immune dysregulation, and show that targeting avenues of estrogen conversion and chronic inflammation work to restore anti-tumor immunity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/616978v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@1ecd90borg.highwire.dtl.DTLVardef@9d7ac8org.highwire.dtl.DTLVardef@e7fb74org.highwire.dtl.DTLVardef@2da524_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

Computational modeling of cell signaling and mutations in pancreatic cancer

Published research articles are rich sources of data when the knowledge is incorporated into models. Complex biological systems benefit from computational modelings ability to elucidate dynamics, explain data and address hypotheses. Modeling of pancreatic cancer could guide treatment of this devastating disease that has a known mutational profile disrupting signaling pathways but no reliable therapies. The approach described here is to utilize discrete modeling of the major signaling pathways, metabolism and the tumor microenvironment including macrophages. This modeling approach allows for abstraction in order to assemble large networks to capture numerous facets of the biological system under investigation. The Hallmarks of Cancer are represented as the processes of apoptosis, autophagy, cell cycle progression, inflammation, immune response, oxidative phosphorylation and proliferation. The model is initialized with pancreatic cancer receptors and mutations and simulated in time. The model portrays the hallmarks of cancer and suggests combinations of inhibitors as therapies.

systems biology↗

bioRxiv2021

Adoptive transfer of allogeneic gamma delta T cells promotes HIV replication in a humanized mouse model

Gamma-delta ({gamma}{delta}) T cells recognize antigens in an MHC-independent manner, with demonstrable cytotoxicity against cancer and virally infected cells. Human immunodeficiency virus (HIV) infection severely depletes the V{gamma}9V{delta}2 (V{delta}2) subset of these T cells in most infected individuals, with the exception of elite controllers. The capacity of V{delta}2 cells to kill HIV-infected targets has been demonstrated in vitro, but this has not been verified in vivo. Here, we examined the immunotherapeutic potential of V{delta}2 cells in controlling HIV replication in vivo and provide the first characterization of reconstituted {gamma}{delta} T cell subsets in the peripheral blood and lymphoid tissue in a humanized mouse model. We demonstrate the depletion of V{delta}2 cells and increase in V{delta}1 cells in the blood following HIV infection, similar to that observed in HIV-infected humans. The functionality of human V{delta}2 cells isolated from humanized mice was confirmed via ex vivo expansion in response to zoledronate and IL-2 treatment. The adoptive transfer of activated V{delta}2 cells failed to control HIV infection in vivo but instead exacerbated viremia by serving as early targets for HIV infection. Our findings suggest that V{delta}2 cells play a critical and unappreciated role as early HIV targets of infection to promote viral dissemination.

immunology↗