Oropharyngeal carcinomas induce circulating monocytes to express a TAM-like pro-tumor expression profile that suppresses T-cell proliferation

Christopher Papayannakos ^1* Mohd Israr ¹ James Allan Devoti ^1,2 Fung Lam ¹ Arnon Arazi ¹ Douglas K. Frank ^1,3 Dev Kamdar ³ Lucio M. Pereira ³ Nagashree Seetharamu ⁴ Bettie M Steinberg ^1,3,5 Vincent R. Bonagura ^1,2*

• ¹ Institute of Molecular Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, United States
• ² Department of Pediatrics, Steven and Alexandra Cohen Children’s Medical Center of New York, Barbara and Donald Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States
• ³ Department of Otolaryngology, Long Island Jewish Medical Center, Barbara and Donald Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States
• ⁴ Department of Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States
• ⁵ Department of Molecular Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States

Tumor-associated macrophages (TAMs) are recruited from circulating monocytes. TAMs drive tumor-growth and establish an immunosuppressive tumor microenvironment. Initial events in transition from resting monocytes to TAMs are poorly understood. Most oropharyngeal cancers (OPC) are caused by HPV16. Here, we report that monocytes from OPC patients and control monocytes treated with OPC conditioned media express a repertoire of pro-tumor mediators that is characteristic of TAMs. Single-cell RNAseq of patient and control monocytes stimulated with conditioned media from OPC cell lines showed induction of multiple protumor genes including CXCL1, CXCL5, CXCL8, SPP1, IL1B, GPNMB, and FABP5. Induction of these genes was confirmed using a cohort of patients and control circulating monocytes. Patient monocytes had higher baseline levels or achieved higher levels after stimulation than control monocytes. We also observed a subset of patient monocytes with high baseline levels of CXCL9/-10/-11 expression that resisted downregulation in response to stimulation, a potential sign of a more favorable TME. CXCL9/-10/-11 expression in OPC tumor biopsies compared to clinically normal tissue correlated with patient outcome. We used OPC cell line spheroids as a tumor model to assess TAM expression phenotype and impact on T-cell proliferation. Spheroid TAMs derived from control monocytes maintained the pro-tumor repertoire seen with control monocytes stimulated by tumor line-conditioned media. These TAMs suppress T-cell proliferation. Inhibition of COX-2 or IL1 signaling during differentiation into TAMs partially blocked the suppression of T-cell proliferation. Targeting the early transition of monocytes into pro-tumor TAMs could be used to develop new therapies for OPC.