Circulating monocytes associated with anti-PD-1 resistance in human biliary cancer induce T cell paralysis

Suppressive myeloid cells can contribute to immunotherapy resistance, but their role in response to checkpoint inhibition (CPI) in anti-PD-1 refractory cancers, such as biliary tract cancer (BTC), remains elusive. We use multiplexed single-cell transcriptomic and epitope sequencing to profile greater than 200,000 peripheral blood mononuclear cells from advanced BTC patients (n = 9) and matched healthy donors (n = 8). Following anti-PD-1 treatment, CD14+ monocytes expressing high levels of immunosuppressive cytokines and chemotactic molecules (CD14CTX) increase in the circulation of patients with BTC tumors that are CPI resistant. CD14CTX can directly suppress CD4+ T cells and induce SOCS3 expression in CD4+ T cells, rendering them functionally unresponsive. The CD14CTX gene signature associates with worse survival in patients with BTC as well as in other anti-PD-1 refractory cancers. These results demonstrate that monocytes arising after anti-PD-1 treatment can induce T cell paralysis as a distinct mode of tumor-mediated immunosuppression leading to CPI resistance.

676 Altered circulating myeloid states associated with anti-PD-1 resistance induce T cell paralysis in human biliary cancer

Background

Advanced biliary cancers (ABC) have a poor prognosis and low rates of response to immune checkpoint inhibition (CPI), with overall response rates ranging from 3–13%.1–3 Although suppressive myeloid cells have been proposed as a mechanism of resistance to immunotherapy in general, their relationship to response to CPI is unknown.

Methods

We used multiplexed simultaneous single cell RNA sequencing and cell surface proteomics (CITE-seq) to profile circulating immune cells in ABC patients receiving anti-PD-1 at longitudinal timepoints pre-immunotherapy and on treatment, as well as from healthy donors. We also performed single cell RNA sequencing on resected biliary tumors.

Results

We identified a novel population of circulating cancer-enriched myeloid cells (CEM) characterized by chemokines and extracellular matrix digestion-related gene expression, which were present pre-treatment. Anti-PD-1 treatment drove the CEMs into two diverging states that were associated with response or resistance to treatment. CEM induced in non-responders constituted over 40% of the circulating myeloid cells and expressed immunosuppressive programs, including the upregulation of suppressive cytokines and chemokines. The frequency of these myeloid cells were correlated with the abundance of SOCS3-expressing CD4+ T cells. These SOCS3+CD4+ T cells also colocalized with tumor-infiltrating myeloid cells that share CEM gene expression signatures in the biliary cancer microenvironment. Moreover, CEM can directly induce SOCS3-expressing T cells, which despite their naïve phenotype are functionally unresponsive. Finally, expression signatures of CEM and of SOCS3+CD4+ T cells are associated with worse survival in a larger cohort of ABC patients.

Conclusions

These results demonstrate the capacity of CEM to induce T cell paralysis as an alternate mode of tumor-mediated immunosuppression. A deeper understanding of immune cell biology in ABC provides insights for developing novel therapeutics that can overcome immunotherapy resistance in biliary cancer as well as other tumor types.

Trial Registration

NCT02703714

References

Ueno M, et al. Nivolumab alone or in combination with cisplatin plus gemcitabine in Japanese patients with unresectable or recurrent biliary tract cancer: a non-randomised, multicentre, open-label, phase 1 study. Lancet Gastroenterol Hepatol 2019;4:611–621.

Piha-Paul SA, et al. Efficacy and safety of pembrolizumab for the treatment of advanced biliary cancer: results from the KEYNOTE-158 and KEYNOTE-028 studies. Int J Cancer 2020.

Kim RD, et al. A Phase 2 Multi-institutional study of nivolumab for patients with advanced refractory biliary tract cancer. JAMA Oncol 2020;6:888–894.

Ethics Approval

Informed consent was obtained from all patients for participation in the listed trial and for use of blood and tumor samples in research studies.

Abstract 4063: Single cell immune profiling of patients with advanced biliary cancers treated with combination checkpoint inhibition and GM-CSF reveals diverse T cell and myeloid cell mechanisms of action

Background: Advanced biliary cancers (ABC) including cholangiocarcinoma and gallbladder adenocarcinoma are rising in incidence with limited standard treatment options. While checkpoint inhibition (CPI) achieves durable tumor responses in subsets of patients across many malignancies, less than 10% of ABC patients respond to single agent PD-1-targeted therapy. Combination immunotherapy aims to overcome pre-existing and adaptive resistance to immunotherapy. GM-CSF is a cytokine that activates and matures antigen-presenting cells, suggesting the potential to enhance immune responses. The exact mechanisms of action of this cytokine have not been defined in cancer patients. The combination of GM-CSF and anti-CTLA-4 CPI demonstrated safety along with inducing clinical responses in melanoma and prostate cancer. We conducted a phase II trial of the novel combination of GM-CSF and pembrolizumab (Pembro) in patients with ABC which has resulted in durable clinical responses in greater proportion than previously reported with anti-PD-1 monotherapy.

Methods: We assessed peripheral blood mononuclear cells (PBMC) from patients on Pembro monotherapy and combined Pembro/GM-CSF by mass cytometry (CyTOF) and T cell receptor (TCR) sequencing. We explored for the differences between clinical responders versus non-responders.

Results: We find that the addition of GM-CSF to Pembro leads to a higher frequency of myeloid cells overall; however, certain sub-populations of classical monocytes and conventional dendritic cells decreased in peripheral blood following upfront Pembro followed by GM-CSF. GM-CSF did not seem to change the phenotypes or relative frequencies of circulating T cell subsets. We also find that clinical responders possess specific circulating populations of classical monocyte and conventional dendritic cells prior to treatment. Responders also had higher percentages of CD8+ T cells expressing CD39 following Pembro treatment compared to non-responders. Combination therapy with Pembro/GM-CSF led to different effects on the T cell repertoire compared to Pembro alone.

Conclusions: The addition of GM-CSF to Pembro leads to dynamic shifts in myeloid cell subsets in the peripheral blood of ABC patients treated with immunotherapy, whereas Pembro alone led to changes in the activation states of T cell subsets. The TCR repertoire shifts reflect distinct mechanisms of action for Pembro monotherapy versus Pembro/GM-CSF. Future studies will explore the mechanisms driving the increased response rate seen with combination immunotherapy in comparison to Pembro alone in ABC patients, both through the study of peripheral immune responses as well as via immune-profiling of tumors from sequential biopsies of patients on Pembro monotherapy versus combined Pembro/GM-CSF.

Citation Format: Bridget P. Keenan, Whitney Tamaki, Eric Liu, Brandon Chen, Alexander Cheung, John D. Gordan, Brenna Sheldon, Li Zhang, Robin K. Kelley, Lawrence Fong. Single cell immune profiling of patients with advanced biliary cancers treated with combination checkpoint inhibition and GM-CSF reveals diverse T cell and myeloid cell mechanisms of action [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4063.

Insulin analogues: an example of applied medical science

Insulin analogues were developed to try and achieve more physiological insulin replacement from injection in the subcutaneous site. Their pharmacokinetics and pharmacodynamics differ from human insulin when injected subcutaneously because of alterations in the amino acid sequence of the insulin molecule. The rapid-acting insulin analogues, lispro, aspart and glulisine, have a rapid onset of action and shorter duration of action because of changes to the B26-30 portion of insulin inhibiting formation of dimers and hexamers. They appear to improve postprandial glucose, incidence of hypoglycaemia and patient satisfaction and, when used in combination with basal insulin analogues, improve glycosylated haemoglobin in comparison to conventional insulin therapy. Additionally, they have been successfully used in children, pregnant women, in pump therapy and as part of premixed biphasic regimens. The two basal insulin analogues, glargine and detemir, developed by adjusting the isoelectric point and adding a fatty acid residue, respectively, have a protracted duration of action and a relatively smooth profile. Their pharmacokinetic and pharmacodynamic profiles have been assessed using euglycaemic clamp protocols. Both analogues have a longer duration of action, less of a peak of activity and a reduced variability with repeated injection. There is some evidence to suggest that detemir may have a slight hepatoselective effect. Clinical studies have shown a lower relative risk of hypoglycaemia and detemir appears to have a weight-sparing action. Insulin analogues represent a successful example of applied medical science.

Transcripts of the MHM region on the chicken Z chromosome accumulate as non-coding RNA in the nucleus of female cells adjacent to the DMRT1 locus

The male hypermethylated (MHM) region, located near the middle of the short arm of the Z chromosome of chickens, consists of approximately 210 tandem repeats of a BamHI 2.2-kb sequence unit. Cytosines of the CpG dinucleotides of this region are extensively methylated on the two Z chromosomes in the male but much less methylated on the single Z chromosome in the female. The state of methylation of the MHM region is established after fertilization by about the 1-day embryonic stage. The MHM region is transcribed only in the female from the particular strand into heterogeneous, high molecular-mass, non-coding RNA, which is accumulated at the site of transcription, adjacent to the DMRT1 locus, in the nucleus. The transcriptional silence of the MHM region in the male is most likely caused by the CpG methylation, since treatment of the male embryonic fibroblasts with 5-azacytidine results in hypo-methylation and active transcription of this region. In ZZW triploid chickens, MHM regions are hypomethylated and transcribed on the two Z chromosomes, whereas MHM regions are hypermethylated and transcriptionally inactive on the three Z chromosomes in ZZZ triploid chickens, suggesting a possible role of the W chromosome on the state of the MHM region.

Host-parasite evolution: general principles and avian models

edited by D.H. Clayton and J. Moore, Oxford University Press, 1997. pound60.00 (hbk)/ pound25.00 (pbk) (xi+473 pages) ISBN 0 19 854893 1/0 19 854892/3.

Community care services for the mentally ill: consumers' views

In this study a broadly representative sample of clients in the City of Westminster, receiving Care in the Community for reasons of mental ill-health, were interviewed regarding their experiences of, and levels of satisfaction with, services provided. The results reveal the vulnerability of services users, the benefits of community care, the high regard the majority have for their helpers, the limitations imposed by scarce resources, and the negative effects of only loose co-ordination between health and social services. Respondents also provide a rich source of data on how services might be improved.