Abstract Inhibition of KRASG12C (G12Ci) has shown promising clinical activity in several cancers; however, emergence of resistance is a major limitation to long-term benefit. It remains unknown how G12Ci affects the tumor-immune microenvironment and its association with resistance. We investigated the immune-modulatory impact of the G12Ci sotorasib in KrasG12C/Trp53−/− lung and colon carcinoma models. Single-cell RNA sequencing of tumors in both models demonstrated sotorasib-induced loss of proliferative tumor cells and the enrichment of immune-active tumor cells with elevated NF-κB and IFN signaling and elevated MHC-I expression. These changes led to an increased proportion of effector T cells and MHC-IIhigh macrophages in the tumors and a reduced proportion of regulatory myeloid cells. Furthermore, sotorasib-resistant tumors exhibited a marked reduction of MHC-Ihigh immune-active tumor cells and immune cell type changes. Enrichment of immune-active tumor cells was associated directly with sotorasib-induced activation of NF-κB and STAT1, leading to heightened responsiveness to inflammatory cytokines and upregulation of MHC-I and chemokine expression. These findings indicate that modulation of immune-active tumor cell populations is a key mechanism associated with G12Ci therapeutic efficacy and the development of resistance. Watch first author Mohammed L. Ibrahim, B. Pharm, PhD, from California Northstate University College of Medicine describe this article: https://vimeo.com/showcase/12408339?video=1227805308.
Abstract Adoptive cell therapy using tumor-infiltrating lymphocytes (TIL) is effective for treating advanced melanoma but requires surgical tumor resection. Malignant pleural effusions (MPE) may provide a more accessible source of tumor-reactive T cells. Synchronously collected MPE, lung metastasis, and blood from a patient with metastatic melanoma were analyzed using high-dimensional flow cytometry, and single-cell RNA/T cell receptor (TCR) sequencing. TCR reactivity to autologous tumor was tested in vitro. The proliferative and cytotoxic capacity of ex vivo expanded T cells was assessed in vitro. MPE contained a higher fraction of CD3+ T cells compared with tumor and was enriched for effector CD8+ T cells and effector memory CD4+ T cells. Compared with TIL, MPE T cells exhibited lower features of T cell exhaustion and higher cytotoxicity signatures. The clonal repertoire of MPE and tumor highly overlapped, including 62.2% of predicted neoantigen-specific (NeoTCR) clonotypes. MHC class I-restricted reactivity was functionally confirmed in two of four selected NeoTCR clonotypes. MPE T cells demonstrated higher proliferative capacity under high-dose IL-2 expansion relative to TIL and achieved comparable MHC class I-dependent tumor killing. Overall, MPE contains polyclonal, tumor-reactive T cells with favorable functional features, supporting MPE as an accessible source for TIL therapy.
Abstract The spatial arrangement of immune cells in the tumor microenvironment (TME) varies widely, from dispersed to clustered and tumor excluded to infiltrating. Multiplexed spatial profiling is an effective means of characterizing tumor-infiltrating lymphocytes (TILs) and immune complexes such as tertiary lymphoid structures (TLS) in the TME. However, few approaches have been described for objectively parametrizing patterns of immune organization and assessing their association with biological or clinical variables. This makes it difficult to evaluate whether a set of tumors is relatively immunologically cold or hot. Here we describe an intuitive set of statistical tools (available in the R package, tlsR) for characterizing lymphocyte patterns in the TME of solid cancers. We applied tlsR to primary prostate cancer (PCa), which is often described as immunologically ‘cold’. Using a cohort of 29 radical prostatectomy specimens stratified into low Gleason-grade (LGG; n=15) and high Gleason-grades (HGG; n =14) we showed that HGG PCa is significantly more infiltrated than LGG PCa with lymphocytes organized into B cell or T cell enriched immune clusters (BICs and TICs). A subset of these ICs had the B and T cell zonation and follicular dendritic cells characteristic of a bona fide TLS. HGGs were also enriched with ICs containing precursor exhausted T cells (Tpex) and proliferating B cells and their tumor compartments harbor granzyme-B+ cytotoxic T cells in contact with cancer cells. Thus, far from being cold, a subset of HGG PCa has features associated with active immune surveillance, a finding with implications for emerging PCa immunotherapies.
Myeloid checkpoint blockade as monotherapy often yields limited benefit, suggesting that multiple inhibitory pathways cooperatively sustain myeloid immunosuppression in the tumor microenvironment (TME). However, strategies to concurrently target multiple myeloid checkpoints remain challenging. Leukocyte immunoglobulin-like receptor A3 (LILRA3) is a soluble LILRA/B family member with unclear immunoregulatory function. Here, we show that LILRA3 is significantly reduced in the serum and tumor tissues of cancer patients, and its systemic levels positively correlate with cytotoxic T cell infiltration and improved survival. LILRA3 suppresses immunosuppressive myeloid cells, enhances pro-inflammatory cytokine production, and inhibits M2 macrophage polarization, thereby indirectly promoting T cell proliferation. Mechanistically, LILRA3 binds to LILRB4 and multiple endogenous LILRB ligands, blocking downstream inhibitory signaling. LILRA3 restrains tumor growth in myeloid-specific LILRB2- and LILRB4-transgenic mice and in humanized mouse models. These findings identify LILRA3 as a natural multi-LILRB signaling antagonist that counteracts myeloid-driven immunosuppression and highlight its potential as a therapeutic immune modulator.
Chimeric antigen receptor (CAR) T-cell therapies have shown limited promise in solid tumors owing to the immunosuppressive tumor microenvironment. TAK-102 is a next-generation, glypican-3 (GPC3)-targeted CAR T-cell therapy engineered to co-express interleukin-7 (IL-7) and chemokine ligand 19 (CCL19), enhancing T-cell survival and trafficking. In this first-in-human, open-label, phase 1, dose-escalation study (ClinicalTrials.gov: NCT04405778), we evaluated a single TAK-102 infusion in 11 patients with GPC3+ advanced solid tumors refractory or intolerant to standard therapies. Patients received TAK-102 at one of three dose levels following leukapheresis and lymphodepletion chemotherapy. The primary endpoints were the incidences of dose-limiting toxicities, treatment-emergent adverse events, and adverse events of special interest. No dose-limiting toxicities were observed. The most common treatment-emergent adverse events were hematologic, including neutropenia and leukopenia (81.8%), and cytokine release syndrome (54.5%), all grade 1-2. No objective responses were observed; however, five patients achieved stable disease (disease control rate, 45.5%). One patient had a 26.1% reduction in tumor size lasting 9 months, accompanied by a 51.6% decline in serum alpha-fetoprotein. Cellular kinetics showed dose-dependent expansion, with the highest exposure at 5 × 10⁸ CAR+ cells/body. Post-treatment biopsies revealed increased CD8+ T-cell infiltration and activation markers, although CAR+ cells were undetectable in tumor tissue. Serum CCL19 levels increased with dose, suggesting immune priming. These findings support a manageable safety profile for TAK-102 and provide early evidence of biological activity in solid tumors. Further studies are warranted to optimize dosing, improve CAR T-cell persistence, and evaluate efficacy in larger patient cohorts.
