Functional neuronal circuits promote disease progression in cancer

The molecular and functional contributions of intratumoral nerves to disease remain largely unknown. We localized synaptic markers within tumors suggesting that these nerves form functional connections. Consistent with this, electrophysiological analysis shows that malignancies harbor significantly higher electrical activity than benign disease or normal tissues. We also demonstrate pharmacologic silencing of tumoral electrical activity. Tumors implanted in transgenic animals lacking nociceptor neurons show reduced electrical activity. These data suggest that intratumoral nerves remain functional at the tumor bed. Immunohistochemical staining demonstrates the presence of the neuropeptide, Substance P (SP), within the tumor space. We show that tumor cells express the SP receptor, NK1R, and that ligand/receptor engagement promotes cellular proliferation and migration. Our findings identify a mechanism whereby intratumoral nerves promote cancer progression.

Nociceptor neurons affect cancer immunosurveillance

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.

Characterization of the Immune Response to PD-1 Blockade during Chemoradiotherapy for Head and Neck Squamous Cell Carcinoma

BACKGROUND

Chemoradiotherapy is a standard treatment for HNSCC. Blockade of the PD-1/L1-2 interaction may represent a target to overcome immune escape during this treatment.

METHODS

Utilizing a HNSCC mEERL C57BL/6 mouse model, we evaluated a PD-1 blockade alone or in combination with cisplatin-based chemoradiotherapy. Next, we evaluated peripheral blood mononuclear cells (PBMCs) with relative PD-1, TIM-3, and LAG-3 expression, and myeloid-derived suppressor-like (MDSC-like) populations from a clinical trial evaluating PD-1 blockade with chemoradiotherapy in HNSCC. Finally, we analyzed the effect of therapy on human T-cell clonality through T-cell Receptor (TCR) sequencing.

RESULTS

Anti-PD-1 monotherapy induced no response in the mEERL model; however, combination with chemoradiotherapy improved tumor clearance and survival. PBMCs from patients treated with this combination therapy demonstrate a decline in circulating T-cell populations with knockdown of PD-1 expressing CD3+CD4+ and CD3+CD8+ T cells during treatment. However, TIM-3, LAG-3 expressing T-cell and MDSC-like populations concordantly rose. During treatment, the TCR repertoire demonstrates overall clonal expansion, with both unique and previously reported T-cell clones.

CONCLUSIONS

Our murine HNSCC model demonstrates efficacy of PD-1 blockade during chemoradiotherapy. However, while PD-1-expressing T cells decreased with this therapy, human PBMC findings also identified an increase in populations contributing to immune exhaustion. These findings further characterize PD-1 blockade during chemoradiotherapy for HNSCC and highlight potential competing mechanisms of immune evasion.

Abstract P019: Intra-tumoral nerves regulate the local immune response at the tumor bed

Patients with highly innervated tumors have a worse prognosis than those with less innervated disease. However, the process by which intra-tumoral nerves contribute to poor outcomes remains unclear. Previously, we identified that head and neck squamous cell carcinomas (HNSCCs) are infiltrated by sensory (TRPV1+) nerves. To map the source of these tumor infiltrating nerves, we intra-tumorally injected the fluorescently tagged nerve tracer lectin, wheat germ agglutinin (WGA), in our hind limb placed HNSCC tumors. Similar to other nerve tracers, WGA is taken up at nerve terminals and retrogradely transported to the neural somas. WGA labeled the somas of dorsal root ganglia (DRG), identifying them as the source of intra-tumoral nerves. Traced nerves were further characterized by immunostaining and identified as TRPV1+ (sensory), consistent with our initial findings. To test the contributions of tumor innervation to tumor growth and survival, wildtype and TRPV1-DTA (genetically deleted of TRPV1+ neurons) mice were implanted with a mouse model of human papillomavirus-induced (HPV+) HNSCC, mEERL cells. The absence of TRPV1 nerves results in slower tumor growth and improves survival. To mechanistically define how depletion of intra-tumoral nerves reduce tumor growth, we first collected tumors 25 days after injection in the hind limb and stained with a 12-color antibody panel. Stained tumors were then analyzed with flow cytometry to identify differences in the infiltrative immune cell populations between tumors grown in C57Bl/6 control mice and our TRPV1-DTA mouse model. Flow cytometry analysis indicated a decrease in the infiltrative myeloid derived suppressor cell (MDSC) population following ablation of TRPV1+ nerves. To understand how loss of TRPV1+ nerves mediate changes in the infiltrative immune cell population we conducted cytokine array analysis of condition media from cancer cells alone and in co-culture with DRG. Results indicate a shift in secreted cytokines following co-culture with DRG. These data indicate that intra-tumoral sensory nerves are recruited from loco-regional DRG to tumors injected in the hind limb. Our data also suggest that ablation of TRPV1+ nerves alter the intra-tumoral MDSC population and, in this way, potentially contributes to tumor growth. Finally, co-culture of mEERL cells with DRG in vitro results in changes in secreted cytokines, potentially explaining the change in the infiltrative immune cell populations. Together, these data indicate a potential role for sensory nerves to regulate the local immune response in developing tumors.

Citation Format: Anthony C. Restaino, Christopher T. Lucido, Jeffrey Barr, Paola D. Vermeer. Intra-tumoral nerves regulate the local immune response at the tumor bed [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P019.

Serum Sickness-Like Reaction in an Adolescent Taking Minocycline for Acne

We report a case of serum sickness-like reaction (SSLR) in a 14-year-old male taking minocycline for acne. The patient presented with urticarial rash, arthralgia/arthritis, and tender lymphadenopathy. Symptoms resolved with discontinuation of minocycline and treatment with prednisone, cetirizine, and ibuprofen. SSLR is a rare complication of minocycline treatment that may go unrecognized and underreported.

Innervation of cervical carcinoma is mediated by cancer-derived exosomes

OBJECTIVE

Recently, our laboratory identified sensory innervation within head and neck squamous cell carcinomas (HNSCCs) and subsequently defined a mechanism whereby HNSCCs promote their own innervation via the release of exosomes that stimulate neurite outgrowth. Interestingly, we noted that exosomes from human papillomavirus (HPV)-positive cell lines were more effective at promoting neurite outgrowth than those from HPV-negative cell lines. As nearly all cervical tumors are HPV-positive, we hypothesized that these findings would extend to cervical cancer.

METHODS

We use an in vitro assay with PC12 cells to quantify the axonogenic potential of cervical cancer exosomes. PC12 cells are treated with cancer-derived exosomes, stained with the pan-neuronal marker (β-III tubulin) and the number of neurites quantified. To assess innervation in cervical cancer, we immunohistochemically stained cervical cancer patient samples for β-III tubulin and TRPV1 (sensory marker) and compared the staining to normal cervix.

RESULTS

Here, we show the presence of sensory nerves within human cervical tumors. Additionally, we show that exosomes derived from HPV-positive cervical cancer cell lines effectively stimulate neurite outgrowth.

CONCLUSIONS

These data identify sensory nerves as components of the cervical cancer microenvironment and suggest that tumor- derived exosomes promote their recruitment.

Cancer exosomes induce tumor innervation

Patients with densely innervated tumors suffer with increased metastasis and decreased survival as compared to those with less innervated tumors. We hypothesize that in some tumors, nerves are acquired by a tumor-induced process, called axonogenesis. Here, we use PC12 cells as an in vitro neuronal model, human tumor samples and murine in vivo models to test this hypothesis. When appropriately stimulated, PC12 cells extend processes, called neurites. We show that patient tumors release vesicles, called exosomes, which induce PC12 neurite outgrowth. Using a cancer mouse model, we show that tumors compromised in exosome release are less innervated than controls. Moreover, in vivo pharmacological blockade of exosome release similarly attenuates tumor innervation. We characterize these nerves as sensory in nature and demonstrate that axonogenesis is potentiated by the exosome-packaged axonal guidance molecule, EphrinB1. These findings indicate that tumor released exosomes induce tumor innervation and exosomes containing EphrinB1 potentiate this activity.

β2-Adrenergic receptor modulates mitochondrial metabolism and disease progression in recurrent/metastatic HPV(+) HNSCC

The incidence of human papillomavirus-associated head and neck squamous cell carcinoma (HPV[ + ] HNSCC) is rapidly increasing. Although clinical management of primary HPV( + ) HNSCC is relatively successful, disease progression, including recurrence and metastasis, is often fatal. Moreover, patients with progressive disease face limited treatment options and significant treatment-associated morbidity. These clinical data highlight the need to identify targetable mechanisms that drive disease progression in HPV( + ) HNSCC to prevent and/or treat progressive disease. Interestingly, β-adrenergic signaling has recently been associated with pro-tumor processes in several disease types. Here we show that an aggressive murine model of recurrent/metastatic HPV( + ) HNSCC upregulates β₂-adrenergic receptor (β2AR) expression, concordant with significantly heightened mitochondrial metabolism, as compared with the parental model from which it spontaneously derived. β-Adrenergic blockade effectively inhibits in vitro proliferation and migratory capacity in this model, effects associated with an attenuation of hyperactive mitochondrial respiration. Importantly, propranolol, a clinically available nonselective β-blocker, significantly slows primary tumor growth, inhibits metastatic development, and shows additive benefit alongside standard-of-care modalities in vivo. Further, via CRISPR/Cas9 technology, we show that the hyperactive mitochondrial metabolic profile and aggressive in vivo phenotype of this recurrent/metastatic model are dependent on β2AR expression. These data implicate β2AR as a modulator of mitochondrial metabolism and disease progression in HPV( + ) HNSCC, and warrant further investigation into the use of β-blockers as low cost, relatively tolerable, complementary treatment options in the clinical management of this disease.

CD137 enhancement of HPV positive head and neck squamous cell carcinoma tumor clearance

Standard-of-care cisplatin and radiation therapy (CRT) provides significant tumor control of human papillomavirus (HPV)-mediated head and neck squamous cell carcinomas (HNSCCs); this effectiveness depends on CRT-mediated activation of the patient's own immune system. However, despite good survival, patients suffer significant morbidity necessitating on-going studies to define novel therapies that alleviate this burden. Given the role of the immune system in tumor clearance, immune modulation may further potentiate the CRT-activated response while potentially decreasing morbidity. CD137, an inducible cell surface receptor found on activated T cells, is involved in differentiation and survival signaling in T cells upon binding of its natural partner (CD137L). A number of studies have shown the effectiveness of targeting this immune-stimulatory pathway in regards to tumor clearance. Here we test its role in HPV+ HNSCC tumor clearance using a previously characterized mouse model. We show that amplification of this stimulatory pathway synergizes with CRT for enhanced tumor clearance. Interestingly, tumor clearance is further potentiated by local tumor cell expression of CD137L.