Biology subjects

Mugarza, E.

Publications and source records attributed to Mugarza, E..

6 recordsLinked to original sources

bioRxiv2024

Spatial proteomic analysis of a lung cancer model reveals regulatory T cells attenuate KRAS-G12C inhibitor-induced immune responses

We recently showed that lung tumor specific KRAS-G12C inhibition causes remodelling of the tumor immune microenvironment from cold to hot. As a result, KRAS-G12C inhibition is able to synergise with anti-PD-1 treatment, but only in tumor models that were already moderately responsive to immune checkpoint blockade at baseline. To investigate mechanisms that restrain immunotherapy sensitivity in non-responsive tumors, we used multiplex imaging mass cytometry to explore spatial patterns in the tumor microenvironment of the highly immune evasive KRAS mutant murine Lewis Lung Cancer model. Clustering of close neighbour information per cell allowed characterisation of spatial patterns or communities in the tissue. We identified a community harbouring features of localised T-cell activation, where CD4+ and CD8+ T cells and dendritic cells were gathered together. KRAS-G12C inhibition led to increased expression of PD-1 on T cells, CXCL9 expression by dendritic cells, together with increased proliferation and potential cytotoxicity of CD8+ T cells, indicating an effector response. However, we also observed a high incidence of regulatory T cells (Tregs) within this community, which had frequent contact with effector T cells, suggesting that Tregs may be able to dampen anti-tumoral immune responses following KRAS-G12C inhibition. Similar communities were detected in human lung adenocarcinoma clinical samples. Depleting Tregs in vivo with anti-CTLA-4 antibody rescued the anti-tumor immune response and led to enhanced tumor control in combination with anti-PD-1 and KRAS-G12C inhibitor. We therefore propose use of KRAS-G12C inhibitor in combination with Treg depletion as a therapeutic opportunity that increases anti-tumoral immune responses and initiates tumor regression. One sentence summarySpatial analysis identified regulatory T cells as potential source of local T cell repression, mediating resistance to KRAS-G12Ci and anti-PD1 therapy.

cancer biology↗

bioRxiv2024

Combining RASG12C(ON) inhibitor with SHP2 inhibition sensitises immune excluded lung tumours to immune checkpoint blockade: a strategy for turning cold tumours hot

Mutant selective drugs targeting the inactive, GDP-bound form of KRASG12C have been approved for use in lung cancer, but responses are short-lived due to rapid development of resistance. In this study we use a novel covalent tri-complex inhibitor, RMC-4998, that targets RASG12C in its active, GTP-bound form to investigate treatment of KRAS mutant lung cancer in various immune competent mouse models. While this RASG12C(ON) inhibitor was more potent than the KRASG12C(OFF) inhibitor adagrasib, rapid pathway reactivation was still observed. This could be delayed using combined treatment with a SHP2 inhibitor, RMC-4550, which not only impacted RAS pathway signalling within the tumour cells but also remodelled the tumour microenvironment (TME) to be less immunosuppressive and promoted interferon responses. In an inflamed, "hot", mouse model of lung cancer, RASG12C(ON) and SHP2 inhibitors in combination drive durable responses by suppressing tumour relapse and inducing development of immune memory, which can also be induced by combination of RASG12C(ON) and PD-1 inhibitors. In contrast, in an immune excluded, "cold", mouse model of lung cancer, combined RASG12C(ON) and SHP2 inhibition does not cause durable responses, but does sensitise tumours to immune checkpoint blockade, enabling efficient tumour rejection, accompanied by significant TME reorganization, including depletion of immunosuppressive innate immune cells and recruitment and activation of T and NK cells. These preclinical results demonstrate the potential of the combination of RASG12C(ON) inhibitors with SHP2 inhibitors to sensitize anti-PD-1 refractory tumours to immune checkpoint blockade by stimulating anti-tumour immunity as well as by targeting KRAS-driven proliferation in tumour cells.

cancer biology↗

bioRxiv2023

In vivo CRISPR screen identifies KRAS-induced COX-2 as a driver of immune evasion and immunotherapy resistance in lung cancer

Oncogenic KRAS impairs anti-tumour immune responses, but effective strategies to combine KRAS inhibitors and immunotherapies have so far proven elusive. In vivo CRISPR-Cas9 screening in an immunogenic murine lung cancer model identifies mechanisms by which oncogenic KRAS promotes immune evasion, most notably expression of immunosuppressive cyclooxygenase-2 (COX-2) in cancer cells. Oncogenic KRAS was a potent inducer of COX-2 in both mouse and human lung cancer which was suppressed using KRAS inhibitors. COX-2 acting via prostaglandin E2 (PGE2) promotes resistance to immune checkpoint blockade (ICB) in both mouse and human lung adenocarcinoma. Targeting COX-2/PGE2 remodelled the tumour microenvironment by inducing pro-inflammatory polarisation of myeloid cells and influx of activated cytotoxic CD8+ T cells, which increased the efficacy of ICB. Restoration of COX-2 expression contributed to tumour relapse after prolonged KRAS inhibition. We propose testing COX-2/PGE2 pathway inhibitors in combination with KRAS G12C inhibition or ICB in patients with KRAS-mutant lung cancer.

cancer biology↗

bioRxiv2021

Therapeutic KRASG12C inhibition drives effective interferon-mediated anti-tumour immunity in immunogenic lung cancers

Recently developed KRASG12C inhibitory drugs are beneficial to lung cancer patients harbouring KRASG12C mutations, but drug resistance frequently develops. Due to the immunosuppressive nature of the signaling network controlled by oncogenic KRAS, these drugs can indirectly affect anti-tumour immunity, providing a rationale for their combination with immune checkpoint blockade. In this study, we have characterised how KRASG12C inhibition reverses immune suppression driven by oncogenic KRAS in a number of pre-clinical lung cancer models with varying levels of immunogenicity. Mechanistically, KRASG12C inhibition upregulates interferon signaling via Myc inhibition, leading to reduced tumour infiltration by immunosuppressive cells, enhanced infiltration and activation of cytotoxic T cells, and increased antigen presentation. However, the combination of KRASG12C inhibitors with immune checkpoint blockade only provides synergistic benefit in the most immunogenic tumour model. KRASG12C inhibition fails to sensitize cold tumours to immunotherapy, with implications for the design of clinical trials combining KRASG12C inhibitors with anti-PD1 drugs. One sentence summaryKRAS inhibition mobilizes anti-tumour immunity in immunogenic lung cancer models through derepressing interferon signaling via repression of Myc.

cancer biology↗

bioRxiv2021

Characterisation of tumour immune microenvironment remodelling following oncogene inhibition in preclinical studies using an optimised imaging mass cytometry workflow

Mouse models are critical in pre-clinical studies of cancer therapy, allowing dissection of mechanisms through chemical and genetic manipulations that are not feasible in the clinical setting. In studies of the tumour microenvironment (TME), multiplexed imaging methods can provide a rich source of information. However, the application of such technologies in mouse tissues is still in its infancy. Here we present a workflow for studying the TME using imaging mass cytometry with a panel of 27 antibodies on frozen mouse tissues. We optimise and validate image segmentation strategies and automate the process in a Nextflow-based pipeline (imcyto) that is scalable and portable, allowing for parallelised segmentation of large multi-image datasets. With these methods we interrogate the remodelling of the TME induced by a KRAS G12C inhibitor in an immune competent mouse orthotopic lung cancer model, highlighting the infiltration and activation of antigen presenting cells and effector cells.

cancer biology↗

bioRxiv2020

APOBEC3B expression generates an immunogenic model of Kras mutant lung cancer

Mutations in oncogenes such as KRAS and EGFR cause a high proportion of lung cancers. Drugs targeting these proteins cause tumour regression but ultimately fail to cure these cancers, leading to intense interest in how best to combine them with other treatments, such as immunotherapies. However, preclinical systems for studying the interaction of lung tumours with the host immune system are inadequate, in part due to the low tumour mutational burden in genetically engineered mouse models. Here we set out to develop mouse models of mutant KRAS-driven lung cancer with an elevated tumour mutational burden by expressing the human DNA cytosine deaminase, APOBEC3B, to mimic the mutational signature seen in human lung cancer. This failed to substantially increase clonal tumour mutational burden and autochthonous tumours remained refractory to immunotherapy. However, by establishing clonal cell lines from these tumours we generated an immunogenic syngeneic transplantation model of KRAS mutant lung adenocarcinoma that was sensitive to immunotherapy. Unexpectedly, we found that anti-tumour immune responses were not directed against neoantigens but instead targeted derepressed endogenous retroviral antigens. The ability of KRASG12C inhibitors to cause regression of KRASG12C-expressing versions of these tumours was markedly potentiated by the adaptive immune system, providing a unique opportunity for the study of combinations of targeted and immunotherapies in immune-hot lung cancer.

cancer biology↗