John Joseph Powers

Accessibility of immune cells to the tumor microenvironment (TME) in many solid tumors can be influenced by extracellular matrix (ECM) deposition, organization, and remodeling within tumor stroma. Specifically, lysyl hydroxylase-2 (LH2)-catalyzed lysine hydroxylation in type-I collagen telopeptides leads to formation of intermolecular collagen cross-links creating a stiffened and proteolytically resistant, stable ECM. Advanced head and neck squamous cell carcinomas (HNSCC) frequently exhibit desmoplasia with elevated LH2 expression, and Immune-checkpoint (ICI) therapy is effective in only <20% patients, suggesting that ECM remodeling mechanistically governs the composition and function of TME infiltrates. We show that elevated LH2 and collagen alignment promotes stromal accumulation of CD8⁺ T-cells, and poor response to ICI in HPV-HNSCCs. Integration of clinical biopsies, transcriptomic datasets, and an immunocompetent syngeneic mouse model revealed that aligned collagen spatially restricts adhesion G protein–coupled receptor positive (ADGRG1⁺) CD8⁺ T-cells to activate a non-canonical GPCR-mediated mechanosensory program that drives dysfunction and exhaustion. Statement of significance: Desmoplasia is common in solid tumors, and immune checkpoint inhibitors benefit only some patients. Current biomarkers like PD-L1 and TMB have limited value. Our findings reveal a previously unrecognized collagen-ADGRG1 mechanosensory immune checkpoint, offering a clinically tractable, spatially resolved biomarker to better stratify patients for immunotherapy.

Cellular plasticity plays essential roles in development including organogenesis and tissue homeostasis. The epithelial-to-mesenchymal transition (EMT) is no longer considered a binary switch but rather a dynamic process characterized by a continuum of metastable intermediates having unique features. This epithelial-mesenchymal (E/M) plasticity can be co-opted by cancer cells to promote dedifferentiation that results in hybrid E/M states which increase tumor heterogeneity and generate distinct molecular and phenotypic adaptations that promote drug resistance, dormancy, recurrence, and/or cell invasion and metastasis. The mechanisms that coordinate and maintain metastable hybrid E/M states are poorly understood, and here we report they are controlled by the master transcription factor CREB which regulates adaptive response genes necessary for E/M plasticity. Specifically, a CREB-dependent head and neck cancer model validated the role of CREB in cancer cell plasticity and revealed that it controls a non-canonical EMT gene signature. Moreover, analyses of this signature across cancer types identified the transcriptional regulators VGLL3 and KLF3 as core PanCancer mediators of hybrid E/M states, and gain- and loss-of-function studies established that CREB regulates E/M plasticity by coordinating VGLL3 and KLF3 to drive metastasis.

Chronic lymphocytic leukemia (CLL) presents challenges in treatment despite advancements in targeted therapies, often facing resistance or relapse. Chronic inflammation plays a significant role in CLL biology, with heightened inflammatory responses and immune dysfunction. Elevated levels of inflammatory cytokines support this notion. Activating signaling pathways such as NF-κB, Phosphoinositide 3-kinase delta (PI3Kδ), and MAPK via B-cell receptors and CD40 confers advantages to leukemic lymphocytes. Our research focuses on the proinflammatory protein S100A9 in CLL progression. We previously described that patients with CLL release exosomes containing S100A9 during disease progression, correlating with NF-κB activation. S100A9, known for its role in autoimmune diseases and cancers, modulates the antitumor immune response by influencing myeloid-derived suppressor cells. Receptors for S100A9 include Toll-like receptor 4, receptor for advanced glycation end products, and extracellular matrix metalloproteinase inducer (EMMPRIN). We identified a novel molecular mechanism involving the S100A9-EMMPRIN interaction in CLL using primary cells and an in vivo CLL mouse model (Eμ-TCL1). Additionally, we developed an Eμ-TCL1/S100A9–/– mouse model and explored pharmacological targeting of S100A9 in a patient-derived xenograft model, highlighting S100A9 as a promising therapeutic target in CLL with potential clinical applications.

An unmet clinical need in chronic lymphocytic leukemia (CLL) is emerging due to the rapidly expanding group of patients with double refractory (Bruton's tyrosine kinase- and B-cell lymphoma 2-inhibitor) disease. So far, autologous T-cell–based therapies, including chimeric antigen receptor (CAR) T cells, have limited success in CLL, which has been attributed to an acquired CLL-mediated T-cell dysfunction and subset skewing toward effector cells at the expense of memory formation. T-cell responses rely on dynamic metabolic processes, particularly mitochondrial fitness. Although mitochondrial disruptions have been observed in solid tumor–infiltrating lymphocytes, their impact on T-cell immunity in lymphoproliferative disorders is unknown. Recent findings indicate that mitochondrial mass in CAR T cells correlates with CLL clinical outcomes. This prompted our investigation into the mitochondrial fitness in CLL T cells. Integrated metabolic and functional analyses revealed impaired, depolarized mitochondria across all T-cell subsets in untreated patients with CLL, leading to further ex vivo and in vivo mouse studies on the underlying signaling alterations. Multiomics profiling of transcriptome and epigenome revealed significant alterations in mitochondrial signaling, diminished adenosine monophosphate-activated protein kinase and autophagy activity, and upregulated glycolysis coupled with hyperactivation of Akt. Inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway during CLL T-cell culture induced metabolic reprogramming, enhancing mitochondrial activity, expression of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha, and memory differentiation. Underscoring clinical relevance, supplementation with the PI3Kδ inhibitor idelalisib during CAR T-cell manufacturing improved persistence and long-term leukemia-free remissions in an immunocompetent murine model. Our study suggests that modulating the abnormal CLL T-cell metabolism can enhance the efficacy of autologous T-cell therapies.

There is a critical unmet need for safe and efficacious neoadjuvant treatment for cisplatin-ineligible patients with muscle invasive bladder cancer. We launched a Phase 1b study using the combination of intravesical cretostimogene grenadenorepvec (oncolytic serotype 5 adenovirus encoding granulocyte-macrophage colony stimulating factor) with systemic nivolumab in cisplatin-ineligible patients with cT2-4aN0-1M0 muscle invasive bladder cancer. The primary objective was to measure safety and the secondary objective to assess the antitumor efficacy of the combination. No dose limiting toxicity was encountered in 21 patients enrolled and treated. Combination treatment achieved a pathologic complete response rate of 42.1%, which was associated with baseline free E2F activity and tumor mutational burden. Although T cell infiltration was broadly induced following intravesical oncolytic virotherapy, the formation and maturation of tertiary lymphoid structures was specifically associated with complete response, emphasizing the importance of adaptive humoral immune responses. Together, these results highlight the potential of this combination regimen to enhance therapeutic efficacy in cisplatin-ineligible patients with muscle invasive bladder cancer, warranting additional study as a neoadjuvant therapeutic option. ClinicalTrials.gov identifier: NCT04610671.

The pathogenesis of cutaneous T-cell lymphoma (CTCL) remains unclear. Using single-cell RNA or T-cell receptor (TCR) sequencing of 32 619 CD3+CD4+ and CD26+/CD7+ and 29 932 CD3+CD4+ and CD26−/CD7− lymphocytes from the peripheral blood of 7 patients with CTCL, coupled to single-cell ATAC-sequencing of 26,411 CD3+CD4+ and CD26+/CD7+ and 33 841 CD3+CD4+ and CD26−/CD7− lymphocytes, we show that tumor cells in Sézary syndrome and mycosis fungoides (MF) exhibit different phenotypes and trajectories of differentiation. When compared to MF, Sézary cells exhibit narrower repertoires of TCRs and exhibit clonal enrichment. Surprisingly, we identified ≥200 mutations in hematopoietic stem cells from multiple patients with Sézary syndrome. Mutations in key oncogenes were also present in peripheral Sézary cells, which also showed the hallmarks of recent thymic egression. Together our data suggest that CTCL arises from mutated lymphocyte progenitors that acquire TCRs in the thymus, which complete their malignant transformation in the periphery.

Supplementary Data from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors

Supplementary Figure from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors

Supplementary Data from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors