Biology subjects

The, S.

Publications and source records attributed to The, S..

5 recordsLinked to original sources

bioRxiv2025

Spatial analysis reveals a novel inflammatory tumor transition state which promotes a macrophage-driven induction of sarcomatoid renal cell carcinoma

Sarcomatoid renal cell carcinoma (sRCC) is an aggressive transdifferentiation of epithelioid clear cell RCC (ccRCC) tumors that shows heightened response to immunotherapy. The underlying biology leading to sarcomatoid transformation and mechanisms contributing to immunotherapy response are not well understood. Novel single cell spatial techniques were used in ccRCC and sRCC tumors from 40 patients to understand the spatial sRCC transformation and corresponding immune changes. A transcriptional transition state in epithelioid ccRCC cells along a continuum to mesenchymal sRCC was identified which expresses high levels of pro-inflammatory cytokines and an immune infiltrate. In vitro studies demonstrated that M2-like macrophages, recruited to the tumor by the transition state, induce full transition to the sarcomatoid state. A combination of increased PD-L1 expression and T-cells recruited by the transition state was observed, consistent with the increased immunotherapy response. This study enriches our understanding of the mechanisms leading to development and immune responsiveness of sRCC paving the way for novel approaches to diminish RCC progression.

cancer biology↗

bioRxiv2024

H3K27M diffuse midline glioma is homologous recombination defective and sensitized to radiotherapy and NK cell-mediated antitumor immunity by PARP inhibition

BackgroundRadiotherapy (RT) is the primary treatment for diffuse midline glioma (DMG), a lethal pediatric malignancy defined by histone H3 lysine 27-to-methionine (H3K27M) mutation. Based on the loss of H3K27 trimethylation producing broad epigenomic alterations, we hypothesized that H3K27M causes a functional double-strand break (DSB) repair defect that could be leveraged therapeutically with PARP inhibitor and RT for selective radiosensitization and antitumor immune responses. MethodsH3K27M isogenic DMG cells and orthotopic brainstem DMG tumors in immune deficient and syngeneic, immune competent mice were used to evaluate the efficacy and mechanisms of PARP1/2 inhibition by olaparib or PARP1 inhibition by AZD9574 with concurrent RT. ResultsH3K27M mutation caused an HRR defect characterized by impaired RT-induced K63-linked polyubiquitination of histone H1 and inhibition of HRR protein recruitment. H3K27M DMG cells were selectively radiosensitized by olaparib in comparison to isogenic controls, and this effect translated to efficacy in H3K27M orthotopic brainstem tumors. Olaparib and RT induced an innate immune response and induction of NK cell (NKG2D) activating ligands leading to increased NK cell-mediated lysis of DMG tumor cells. In immunocompetent syngeneic orthotopic DMG tumors, either olaparib or AZD9574 in combination with RT enhanced intratumoral NK cell infiltration and activity in association with NK cell-mediated therapeutic responses and favorable activity of AZD9574. ConclusionsThe HRR deficiency in H3K27M DMG can be therapeutically leveraged with PARP inhibitors to radiosensitize and induce an NK cell-mediated antitumor immune response selectively in H3K27M DMG, supporting the clinical investigation of best-in-class PARP inhibitors with RT in DMG patients. Key pointsO_LIH3K27M DMG are HRR defective and selectively radiosensitized by PARP inhibitor. C_LIO_LIPARP inhibitor with RT enhances NKG2D ligand expression and NK cell-mediated lysis. C_LIO_LINK cells are required for the therapeutic efficacy of PARP inhibitor and RT. C_LI Importance of the StudyRadiotherapy is the cornerstone of H3K27M-mutant diffuse midline glioma treatment, but almost all patients succumb to tumor recurrence with poor overall survival, underscoring the need for RT-based precision combination therapy. Here, we reveal HRR deficiency as an H3K27M-mediated vulnerability and identify a novel mechanism linking impaired RT-induced histone H1 polyubiquitination and the subsequent RNF168/BRCA1/RAD51 recruitment in H3K27M DMG. This model is supported by selective radiosensitization of H3K27M DMG by PARP inhibitor. Notably, the combination treatment results in NKG2D ligand expression that confers susceptibility to NK cell killing in H3K27M DMG. We also show that the novel brain penetrant, PARP1-selective inhibitor AZD9574 compares favorably to olaparib when combined with RT, prolonging survival in a syngeneic orthotopic model of H3K27M DMG. This study highlights the ability of PARP1 inhibition to radiosensitize and induce an NK cell-mediated antitumor immunity in H3K27M DMG and supports future clinical investigation.

cancer biology↗

bioRxiv2024

Complement C3d enables protective immunity capable of distinguishing spontaneously transformed from non-transformed cells

Immune-surveillance depends in part on the recognition of peptide variants by T cell antigen receptors. Given that both normal B cells and malignant B cells accumulate mutations we chose a murine model of multiple myeloma to test conditions to induce cell-mediated immunity targeting malignant plasma cell (PC) clones but sparing of normal PCs. Revealing a novel function for intracellular C3d, we discovered that C3d engaged T cell responses against malignant plasma cells in the bone marrow of mice that had developed multiple myeloma spontaneously. Our results show that C3d internalized by cells augments immune surveillance by several mechanisms. In one, C3d induces a master transcription regulator, E2f1, to increase the expression of long non-coding (lnc) RNAs, to generate peptides for MHC-I presentation and increase MHC-I expression. In another, C3d increases expression of RNAs encoding ribosomal proteins linked to processing of defective ribosomal products (DRiPs) that arise from non-canonical translation and known to promote immunosurveillance. Cancer cells are uniquely susceptible to increased expression and presentation of mutant peptides given the extent of protein misfolding and accumulation of somatic mutations. Accordingly, although C3d can be internalized by any cell, C3d preferentially targets malignant clones by evoking specific T cell mediated immunity (CMI) and sparing most non-transformed polyclonal B cells and plasma cells with lower mutation loads. Malignant plasma cell deletion was blocked by cyclosporin or by CD8 depletion confirming that endogenous T cells mediated malignant clone clearance. Besides the potential for therapeutic application our results highlight how intracellular C3d modifies cellular metabolism to augment immune surveillance. One Sentence SummaryWe show that intracellular soluble fragment 3d of complement (C3d) induces regression of spontaneous multiple myeloma in mice reducing tumor burden by 10 fold, after 8 weeks. C3d enables cell-mediated immunity to target multiple myeloma clones sparing non-transformed polyclonal B cells and plasma cells with lower mutation loads. We show that C3d increases the expression of ribosomal subunits associated with the translation of defective ribosomal products (DRiPs). C3d also decreases expression of protein arginine methyl transferase (PRMT) 5 which in turn relieves E2f1 repression increasing the expression of Lnc RNAs and derived peptides that evoke anti-tumor cellular immunity. The approach increases MHC-I expression by tumor cells and generates a CMI response that overcomes tumor immune-evasion strategies. SignificanceTumors are immunogenic in part because of somatic mutations that originate novel peptides that once presented on MHC engage cell-mediated immunity (CMI). However, in spite of the higher mutation load most tumors evade immunity. We discovered that a component of the complement system (C3d) overcomes tumor immune evasion by augmenting expression of ribosomal proteins and lncRNAs linked to the presentation of novel peptides by tumor cells. C3d induced CMI targets cancer cells sparing non transformed cells uncovering a novel function for complement in immune surveillance.

immunology↗

bioRxiv2023

Analysis of donor pancreata defines the transcriptomic signature and microenvironment of early pre-neoplastic pancreatic lesions

The adult healthy human pancreas has been poorly studied given lack of indication to obtain tissue from the pancreas in the absence of disease and rapid postmortem degradation. We obtained pancreata from brain dead donors thus avoiding any warm ischemia time. The 30 donors were diverse in age and race and had no known pancreas disease. Histopathological analysis of the samples revealed PanIN lesions in most individuals irrespective of age. Using a combination of multiplex immunohistochemistry, single cell RNA sequencing, and spatial transcriptomics, we provide the first ever characterization of the unique microenvironment of the adult human pancreas and of sporadic PanIN lesions. We compared healthy pancreata to pancreatic cancer and peritumoral tissue and observed distinct transcriptomic signatures in fibroblasts, and, to a lesser extent, macrophages. PanIN epithelial cells from healthy pancreata were remarkably transcriptionally similar to cancer cells, suggesting that neoplastic pathways are initiated early in tumorigenesis. Statement of significanceThe causes underlying the onset of pancreatic cancer remain largely unknown, hampering early detection and prevention strategies. Here, we show that PanIN are abundant in healthy individuals and present at a much higher rate than the incidence of pancreatic cancer, setting the stage for efforts to elucidate the microenvironmental and cell intrinsic factors that restrain, or, conversely, promote, malignant progression.

cancer biology↗

bioRxiv2021

Extrinsic KRAS signaling shapes the pancreatic microenvironment through fibroblast reprogramming.

Oncogenic KRAS is the hallmark mutation of human pancreatic cancer and a driver of tumorigenesis in genetically engineered mouse models of the disease. While the tumor cell-intrinsic effects of oncogenic Kras expression have been widely studied, its role in regulating the extensive pancreatic tumor microenvironment is less understood. Using a genetically engineered mouse model of inducible and reversible oncogenic Kras expression and a combination of approaches that include mass cytometry and single cell RNA sequencing, we have discovered that non-cell autonomous (i.e., extrinsic) oncogenic KRAS signaling reprograms pancreatic fibroblasts, activating an inflammatory gene expression program. As a result, fibroblasts become a hub of extracellular signaling, mediating the polarization and function of pro-tumorigenic myeloid cells while also preventing tissue repair. Our study provides fundamental new knowledge on the mechanisms underlying the formation of the fibroinflammatory stroma in pancreatic cancer and highlights stromal pathways with the potential to be exploited therapeutically.

cancer biology↗