Solid tumours are innervated by nerve fibres that arise from the autonomic and sensory peripheral nervous systems1–5. Whether the neo-innervation of tumours by pain-initiating sensory neurons affects cancer immunosurveillance remains unclear. Here we show that melanoma cells interact with nociceptor neurons, leading to increases in their neurite outgrowth, responsiveness to noxious ligands and neuropeptide release. Calcitonin gene-related peptide (CGRP)—one such nociceptor-produced neuropeptide—directly increases the exhaustion of cytotoxic CD8+ T cells, which limits their capacity to eliminate melanoma. Genetic ablation of the TRPV1 lineage, local pharmacological silencing of nociceptors and antagonism of the CGRP receptor RAMP1 all reduced the exhaustion of tumour-infiltrating leukocytes and decreased the growth of tumours, nearly tripling the survival rate of mice that were inoculated with B16F10 melanoma cells. Conversely, CD8+ T cell exhaustion was rescued in sensory-neuron-depleted mice that were treated with local recombinant CGRP. As compared with wild-type CD8+ T cells, Ramp1−/− CD8+ T cells were protected against exhaustion when co-transplanted into tumour-bearing Rag1-deficient mice. Single-cell RNA sequencing of biopsies from patients with melanoma revealed that intratumoral RAMP1-expressing CD8+ T cells were more exhausted than their RAMP1-negative counterparts, whereas overexpression of RAMP1 correlated with a poorer clinical prognosis. Overall, our results suggest that reducing the release of CGRP from tumour-innervating nociceptors could be a strategy to improve anti-tumour immunity by eliminating the immunomodulatory effects of CGRP on cytotoxic CD8+ T cells.

Diabetes is a common condition characterized by persistent hyperglycemia. High blood sugar primarily affects cells that have a limited capacity to regulate their glucose intake. These cells include capillary endothelial cells in the retina, mesangial cells in the renal glomerulus, Schwann cells, and neurons of the peripheral and central nervous systems. As a result, hyperglycemia leads to largely intractable complications such as retinopathy, nephropathy, hypertension, and neuropathy. Diabetic pain neuropathy is a complex and multifactorial disease that has been associated with poor glycemic control, longer diabetes duration, hypertension, advanced age, smoking status, hypoinsulinemia, and dyslipidemia. While many of the driving factors involved in diabetic pain are still being investigated, they can be broadly classified as either neuron -intrinsic or -extrinsic. In neurons, hyperglycemia impairs the polyol pathway, leading to an overproduction of reactive oxygen species and reactive nitrogen species, an enhanced formation of advanced glycation end products, and a disruption in Na+/K+ ATPase pump function. In terms of the extrinsic pathway, hyperglycemia leads to the generation of both overactive microglia and microangiopathy. The former incites a feed-forward inflammatory loop that hypersensitizes nociceptor neurons, as observed at the onset of diabetic pain neuropathy. The latter reduces neurons' access to oxygen, glucose and nutrients, prompting reductions in nociceptor terminal expression and losses in sensation, as observed in the later stages of diabetic pain neuropathy. Overall, microglia can be seen as potent and long-lasting amplifiers of nociceptor neuron activity, and may therefore constitute a potential therapeutic target in the treatment of diabetic pain neuropathy.

Phenotypic screening is an ideal strategy for the discovery of novel bioactive molecules. Using a customized high-throughput screening (HTS) assay employing primary T lymphocytes, we screened a small library of 4,398 compounds with unknown biological function/target to identify compounds eliciting immunomodulatory properties and discovered a sulfonyl-containing hit, we named InhiTinib. This compound inhibited interferon (IFN)-gamma production and proliferation of primary CD3 + T cells without inducing cell death. In contrast, InhiTinib triggered apoptosis in several murine and human cancer cell lines. Besides, the compound was well tolerated by immunocompetent mice, triggered tumor regression in animals with pre-established EL4 T-cell lymphomas, and prolonged the overall survival of mice harboring advanced tumors. Altogether, our data demonstrate the anti-cancer properties of InhiTinib, which can henceforth bridge to wider-scale biochemical and clinical tests following further in-depth pharmacodynamic studies.

Solid tumors are innervated by nerve fibers that arise from the autonomic and sensory peripheral nervous systems. In prostate cancer, doublecortin-expressing neural progenitors initiate autonomic adrenergic neurogenesis1 which facilitates tumor development and dissemination2, via an angiogenic switch that fuels cancer growth3,4. Similarly, a loss of TP53 drives the reprogramming of tumor-innervating sensory nerves into adrenergic neurons in head and neck tumors, which promotes tumor growth5. However, the impact of tumor neo-innervation by pain-initiating sensory neurons remains unclear. We show that melanoma cells interact with nociceptors, increasing neurite outgrowth, responsiveness to noxious ligands, and neuropeptide release. In turn, CGRP, a nociceptor-produced neuropeptide, directly increases exhaustion of cytotoxic CD8+ T-cells (PD1+Lag3+Tim3+IFNγ-), limiting their capacity to eliminate melanoma. Genetic NaV1.8 or TRPV1 lineage ablation, local pharmacological silencing or blockade of neuropeptide release from tumor-innervating nociceptors, and the antagonism of the CGRP receptor RAMP1, all blunt tumor-infiltrating leukocyte exhaustion, and tumor growth, nearly tripling survival of B16F10-inoculated mice. Inversely, CD8+ T-cell exhaustion increased following optogenetic activation of tumor-innervating NaV1.8 neurons+ and was rescued in sensory neuron depleted mice treated with recombinant CGRP. In comparison to wild-type CD8+ T-cells, RAMP1-/- CD8+ T-cells were protected from undergoing exhaustion when co-transplanted into tumor-bearing Rag1 deficient mice. Single-cell RNA sequencing of patient tumors revealed that intratumoral RAMP1-expressing CD8+ T-cells are more exhausted than their RAMP1 negative counterparts. RAMP1 expression in intratumoral CD8+ T-cells was also associated with resistance to immune checkpoint inhibitor treatment, while RAMP1 overexpression within the tumor correlated with a worse clinical prognosis. We conclude that reducing CGRP release from tumor-innervating nociceptors, by eliminating its immunomodulatory action on cytotoxic CD8+ T-cells, constitutes a useful strategy to safeguard anti-tumor immunity.

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