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A spatially resolved atlas of gastric cancer characterises a lymphocyte aggregated region [bulk RNA-seq]

ABSTRACT: The tumour microenvironment (TME) is a focal point in cancer immunotherapy: its cellular composition and spatial organisation, especially the distribution of lymphocytes, can affect the clinical outcomes of cancer patients. In addition, the function of a cell differs depending on its spatial location and interaction with neighbouring cells. Here, by integrating single-cell transcriptomics with spatial transcriptomics, we survey how the spatial distribution of different cell types varies across diverse histological regions of gastric cancer. Notably, tertiary lymphoid structures (TLSs), a tissue architecture harbouring lymphocytes more than any other region within the TME, possess great potential in modulating anti-tumorigenic immunity by elevating an array of genes (FDCSP and CCL19) principally involved in lymphocyte recruitment and activation. Our findings advance the understanding of TLSs in contributing to anti-tumorigenic immunity in a spatially resolved context, which could be further leveraged as a predictive marker for immunotherapy response.

ORGANISM(S): Homo sapiens

PROVIDER: GSE270679 | GEO | 2025/12/03

REPOSITORIES: GEO

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Project description:Background and aims: Tertiary lymphoid structures (TLSs) are formed in many cancer types and have been correlated with better prognosis and response to immunotherapy. In liver cancer, TLSs have been reported to be pro-tumorigenic as they harbor tumor progenitor cells and nurture their growth. The processes involved in TLS development and the acquisition of a pro- or anti-tumorigenic phenotype in cancer are largely unknown. RORc expressing immune cells have been previously implicated in TLS formation, however, their role in TLS development in the context of inflammation-associated liver cancer remains unexplored. Methods: IKKβ(EE)Hep mice, exhibiting chronic liver inflammation and TLS formation followed by liver cancer, were crossed with RORc knockout mice to explore the effect of RORc on TLS and tumor formation. Transcriptional, proteomic and immunohistochemical techniques were used to analyze TLS phenotypes. CD4, CD8 and B cell depletions were used to analyze their contribution to liver TLS and tumor formation. Results: RORc expressing cells were detected within TLSs of both human patients and mice which develop intrahepatic cholangiocarcinoma. In mice, RORc expressing cells negatively regulate TLS formation, since in their absence TLSs form in excess. CD4 cells are essential for liver TLS formation whereas B cells are required for TLS formation specifically in the absence of RORc expressing cells. Importantly, in chronically inflamed livers lacking RORc expressing cells, TLSs become anti-tumorigenic, resulting in reduced tumor load. Comparing liver pro- and anti-tumorigenic TLSs, revealed enrichment of exhausted CD8 cells that retained effector functions, as well as germinal center B cells and plasma cells in anti-tumorigenic TLSs. Cell depletion experiments revealed a role mainly for B cells in limiting tumor development, possibly via tumor-directed antibodies. Conclusions: RORc expressing cells negatively regulate B cell responses, and facilitate the pro-tumorigenic functions of hepatic TLSs.

Project description:Immunotherapy provides an alternative approach for cancer treatment. However, in-depth analyses of the effects of immunotherapy on the tumor microenvironment (TME) have not been conducted in non-melanoma tumors. Here we describe changes in the pancreatic ductal adenocarcinoma (PDAC) TME following immunotherapy treatment, and show for the first time that vaccine-based immunotherapy directly alters the TME, inducing neogenesis of tertiary lymphoid structures that convert immunologically quiescent tumors into immunologically active tumors. Alterations in five pathways important for immune modulation and lymphoid structure development (TH17/Treg, NFkB, Ubiquitin-proteasome, Chemokines/chemokine receptors, and Integrins/adhesion molecules) in vaccine-induced intratumoral lymphoid aggregates were associated with improved post-vaccination responses. Additional studies in other cancers and patients treated with other forms of immunotherapy are warranted to further develop signatures defined in intratumoral lymphoid structures into biomarkers that predict effective anti-tumor immune responses. These signatures may also expose therapeutic targets for promoting more robust antitumor immune responses in the TME. Between July 2008 and September 2012, 59 patients were enrolled into an ongoing study of an irradiated, allogeneic GM-CSF-secreting pancreatic tumor vaccine (GVAX) administered intradermally either alone or in combination with immune modulatory doses of cyclophophamide (Cy) as neoadjuvant and adjuvant treatment for patients with resectable pancreatic ductal adenocarcinoma (PDAC). Patients were randomized 1:1:1 to 3 treatment arms. In Arm A, patients received GVAX alone; in Arm B, patients received GVAX plus a single intravenous dose of Cy at 200 mg/m2 1 day prior to each vaccination; in Arm C, patients received GVAX plus oral Cy at 100 mg once daily for 1 week on and 1 week off. Up to 6 GVAX treatments were administered and all of the patients remained in their initial treatment arms throughout the duration of the study. All 59 of the patients received the 1st GVAX treatment 2 weeks +/-4 days prior to surgery. Formalin-fixed paraffin-embedded (FFPE) tissue blocks of surgically resected PDAC were obtained from the pathology archive. FFPE tissue blocks from each subject were stained by H&E immediately before the vaccine therapy-induced lymphoid aggregates were microdissected . To better understand the functional status of these vaccine therapy induced lymphoid aggregate structures, gene microarray analysis on RNA isolated from microdissected lymphoid aggregates was performed. Gene expression was compared among samples grouped according to patient overall survival, post-vaccination induction of enhanced mesothelin-specific T cell responses in peripheral blood lymphocytes (PBL), and the intratumoral CD8+ T effector to FoxP3+ Treg ratio. Post-vaccination induction of enhanced mesothelin-specific T cell responses has been reported to correlate with longer survival in patients treated with Panc GVAX.

Project description:Immunotherapeutics represent highly promising agents with the potential to improve patient outcomes in a variety of cancer types. Unfortunately, single-agent immunotherapy has achieved limited clinical benefit to date in patients suffering from pancreatic ductal adenocarcinoma (PDAC). This may be due to the presence of a uniquely immunosuppressive tumor microenvironment (TME) present in PDACs, which creates a barrier to effective immune surveillance. Critical obstacles to immunotherapy in PDAC tumors include the dense desmoplastic stroma that acts as a barrier to T-cell infiltration and the high numbers of tumor-associated immunosuppressive cells. We have identified hyperactivated focal adhesion kinase (FAK) activity in neoplastic PDAC cells as a significant regulator of the fibrotic and immunosuppressive TME. We found that FAK activity was elevated in human PDAC tissues and correlates with high levels of fibrosis and poor CD8+ cytotoxic T-cell infiltration. Single-agent FAK inhibition (VS-4718) dramatically limited tumor progression, resulting in a doubling of survival in the p48-Cre/LSL-KrasG12D/p53Flox/+ (KPC) mouse model of human PDAC. This alteration in tumor progression was associated with dramatically reduced tumor fibrosis, decreased numbers of tumor-infiltrating immature myeloid cells and immunosuppressive macrophages. We postulated that these desirable effects of FAK inhibition on the TME might render PDAC tumors more sensitive to immunotherapy. Accordingly, we found that VS-4718 rendered the previously unresponsive KPC mouse model responsive to anti-PD1 and anti-CTLA4 antagonists leading to a nearly tripling of survival times. These data suggest that FAK inhibition increases immune surveillance by overcoming the fibrotic and immunosuppressive PDAC TME thus rendering tumors more responsive to immunotherapy. We treated KP orthotopic tumor-bearing mice with vehicle and FAK inhibitor (FAKi) for 14 days, then extracted total RNA from tumor tissues.

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A spatially resolved atlas of gastric cancer characterises a lymphocyte aggregated region [bulk RNA-seq]

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