Tumor-hepatocyte crosstalk drives a hepatic lactate-TGF-β axis of CD8⁺ T cell exhaustion and immunotherapy resistance in small-cell lung cancer liver metastases

Kazi, A.; Cao, Y.; Mohindroo, C.; Joshi, A.; Zhang, Y.; Huang, Y.; Tabe, C.; Schroeder, B.; Andresson, T.; Sharma, A. K.; Thomas, A.

doi:10.64898/2026.07.30.741857

bioRxiv · 10.64898/2026.07.30.741857

Tumor-hepatocyte crosstalk drives a hepatic lactate-TGF-β axis of CD8⁺ T cell exhaustion and immunotherapy resistance in small-cell lung cancer liver metastases

Kazi, A.·Cao, Y.·Mohindroo, C.·Joshi, A.·Zhang, Y.·Huang, Y.·Tabe, C.·Schroeder, B.·Andresson, T.·Sharma, A. K.·Thomas, A.

View original source ↗Export metadata ↓

Abstract

PurposeLiver metastases confer poor outcomes and attenuate the benefit of immunotherapy across solid tumors. This study investigated how the hepatic metastatic niche promotes CD8 T cell dysfunction and immunotherapy resistance in small-cell lung cancer (SCLC). Experimental DesignClinical outcomes and tumor gene expression were integrated with multi-region single-cell RNA sequencing of T cells from rapid-autopsy SCLC metastases, together with spatial transcriptomics. SCLC-hepatocyte conditioned-media models were combined with stable-isotope tracing, mass spectrometry, functional and metabolic assays, and ChIP-qPCR to define mechanisms of CD8 T cell suppression. ResultsLiver metastases were associated with inferior survival and reduced benefit from immune checkpoint blockade. Multi-region single-cell analysis showed that CD8 T cells from liver metastases exhibited an exhaustion-associated state enriched for hypoxia, lactate, and TGF-{beta} programs. SCLC-hepatocyte crosstalk generated a lactate- and TGF-{beta}-rich microenvironment that reduced CD8 T cell effector function, proximal T cell receptor signaling, glycolytic fitness, viability, and proliferation. Stable-isotope tracing demonstrated transfer and accumulation of co-culture-derived lactate in recipient CD8 T cells, with limited entry into downstream pyruvate-linked pathways. Lactate accumulation was accompanied by increased H3K18 lactylation at the PDCD1, LAG3, and TGFB1 regulatory loci. In parallel, SCLC-hepatocyte crosstalk increased paracrine TGF-{beta} and activated canonical SMAD2 signaling in CD8 T cells. TGF-{beta} receptor inhibition restored CD8 T cell proliferation. In the phase III IMpower133 cohort, a combined lactate-TGF-{beta} transcriptional program was associated with inferior survival, most strongly in patients with liver metastases. ConclusionsTumor-hepatocyte crosstalk generates convergent lactate and TGF-{beta} signals that drive CD8 T cell dysfunction in liver metastases. This hepatic immune-metabolic circuit provides a potential mechanism for immunotherapy resistance and supports therapeutic strategies targeting TGF-{beta} signaling in liver-metastatic SCLC. Translational RelevancePatients with SCLC liver metastases have poor outcomes and derive limited benefit from immune checkpoint blockade, but actionable mechanisms of hepatic immune resistance remain undefined. We identify an immune-metabolic circuit in which SCLC-hepatocyte crosstalk generate lactate and TGF-{beta} signals that converge on CD8 T cells. Stable-isotope tracing demonstrates the transfer and accumulation of tumor-hepatocyte-derived lactate in recipient T cells, which causes H3K18 lactylation at exhaustion- and TGFB1-associated loci. In parallel, paracrine TGF-{beta} activates canonical SMAD signaling and reinforces proliferative dysfunction. TGF-{beta} receptor inhibition restores CD8 T cell proliferation. In the phase III IMpower133 cohort, a combined lactate-TGF-{beta} program is associated with inferior survival, particularly among patients with liver metastases. These findings provide a mechanistic and biomarker framework for testing TGF-{beta}-directed strategies in liver-metastatic SCLC, a population with substantial unmet clinical need.

Explore related subjects

cancer biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Kazi, A., Cao, Y., Mohindroo, C., Joshi, A., Zhang, Y., Huang, Y., Tabe, C., Schroeder, B., Andresson, T., Sharma, A. K., Thomas, A.. 2026-07-31. Tumor-hepatocyte crosstalk drives a hepatic lactate-TGF-β axis of CD8⁺ T cell exhaustion and immunotherapy resistance in small-cell lung cancer liver metastases. https://doi.org/10.64898/2026.07.30.741857

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Tissue resident CD4+ memory T-cells mark response to immune checkpoint inhibition in high-grade glioma

Background: Immune checkpoint inhibitors (ICI) are efficacious in many solid tumors, but response in glioma is restricted to a small subgroup. The determinants of response and resistance to ICI remain poorly understood. Methods: Here we exploit a syngeneic hypermutated high-grade glioma model with dichotomous response to combined PD-1 and CTLA-4 inhibition to unravel determinants of tumor-infiltrating T-cells driving response. Tumor-infiltrating T-cells from ICI-responsive and non-responsive tumors were analyzed by single-cell RNA and T-cell receptor sequencing and tumor-reactive T-cell receptor clonotypes were functionally validated to characterize their transcriptional phenotypes. We verify our findings in IDH1 wildtype glioblastoma patients treated with neoadjuvant pembrolizumab. Results: ICI response was associated with intratumoral clonal expansion of tumor-reactive cytotoxic T-cells and increased infiltration of CXCR6+ CD4+ tissue resident memory T-cells (Trm). CD4 stem-like memory T-cells in responding tumors demonstrated elevated interferon responses, following trajectories toward clonally expanded Trm, versus trajectories toward exhaustion in non-responsive tumors. In responsive tumors, CD4+ Trm interacted with infiltrating CXCR3+ tumor-reactive and clonally expanded, yet transcriptionally versatile cytotoxic T-cells. Probing the post neoadjuvant ICI high-grade glioma patient tissue dataset, we confirmed increased CXCR6 expression in CD4+ T cells and the association of CD4+ Trm with prolonged overall survival. Conclusion: These findings identify CD4 tissue-resident memory T-cells as determinants of ICI response in IDH1 wildtype high-grade glioma and warrant their further investigation to improve immunotherapy outcomes.

cancer biology↗

bioRxiv2026

Circadian gene-network distortion in high-risk neuroblastoma across multiple biological reference contexts

Background: The circadian clock regulates cellular homeostasis, and its disruption has been implicated in aggressive neuroblastoma, particularly in tumours harbouring MYCN- amplification. However, it remains unclear whether alterations are restricted to individual clock genes or extend to circadian gene network coordination. We therefore examined circadian clock network disruption in adverse neuroblastoma across multiple biological contexts. Methods: We estimated circadian gene network dysregulation using Delta-CCD in tumours from two neuroblastoma cohorts (SEQC n=498 and Kocak n=649), comparing clinical features associated with outcome across canonical, adrenal-tissue matched, and developmental references. Robustness was assessed by cross-cohort meta-analysis and leave-one-gene-out analyses. Cox proportional hazards models adjusted for clinical covariates assessed association between individual clock gene expression patient outcome. Results: Delta-CCD was highest in tumours classified as high-risk (study-specific definition) across reference contexts in both cohorts. MYCN-amplified tumours showed a more reference-dependent pattern, strongest in adrenal context, while stage 4 tumours showed a similar but weaker pattern. Additional analyses supported the high-risk signal as a distributed network-level alteration rather than a single-gene phenomenon. Conclusions: High-risk neuroblastoma is characterised by robust disruption of coordinated clock gene network organisation across canonical and tissue-matched references, extending beyond individual clock genes. The extent of circadian dysregulation depends on the reference state used.

cancer biology↗

bioRxiv2026

BAP1 loss and PRAME expression converge to remodel the tumor-immune ecosystem during uveal melanoma progression

Uveal melanoma (UM) is characterized by a small number of recurrent genetic alterations that determine metastatic propensity. BAP1 loss and PRAME expression define the dominant prognostic axes in UM, yet how they promote malignant progression remains unclear. We profiled 190,535 cells from normal uvea, uveal nevus, primary and metastatic UM using single-cell transcriptomics, T cell receptor sequencing, spatial transcriptomics and isogenic perturbation models. Normal melanocytes, nevus cells and UM cells formed a transcriptional continuum marked by loss of differentiation and emergence of neural crest-like, stress-responsive, hypoxic-glycolytic and immune-interacting states. BAP1 loss and PRAME expression imposed distinct but convergent immunoregulatory programs, inducing interferon and TNF-NFkB signaling and MHC-I expression, with HLA-E showing the strongest response. These alterations were accompanied by macrophage and CD8+ T cell remodeling. PRAME-enriched tumor regions formed spatially organized niches enriched for macrophages and plasma cells. These findings define BAP1 loss and PRAME expression as distinct but convergent axes of tumor-immune coevolution and nominate HLA-E as a candidate mediator of immune resistance.

cancer biology↗