Role of atypical chemokine receptor ACKR2 in experimental oral squamous cell carcinogenesis.

Background: Chemokines and chemokine receptors are critical in oral tumourigenesis. The atypical chemokine receptor ACKR2 is a scavenger of CC chemokines controlling the availability of these molecules at tumour sites, but the role of ACKR2 in the context of oral carcinogenesis is unexplored.

Methods: In this study, wild-type (WT) and ACKR2 deficient mice (ACKR2) were treated with chemical carcinogen 4-nitroquinoline-1-oxide (4NQO) for induction of oral carcinogenesis. Tongues were collected for macro and microscopic analysis and to evaluate the expression of ACKRs, CC chemokines and its receptors, inflammatory cytokines, angiogenic factors, adhesion molecules and extracellular matrix components.

Results: An increased expression of ACKR2 in squamous cell carcinoma (SCC) lesions of 4NQO-treated WT mice was observed. No significant differences were seen in the ACKR1, ACKR3 and ACKR4 mRNA expression comparing SCC lesions from WT and ACKR2 treated mice. Significantly higher expression of CCL2, IL-6 and IL-17 was detected in ACKR2 treated mice. In contrast, the expression of other CC-chemokines, and receptors, angiogenic factors, adhesion molecules and extracellular matrix components were similarly increased in SCC lesions of both groups. Clinical and histopathological analysis revealed no differences in inflammatory cell recruitment and in the SCC incidence comparing WT and ACKR2 treated mice.

Conclusion: The results suggest that ACKR2 expression regulates inflammation in tumour-microenvironment but the absence of ACKR2 does not impact chemically-induced oral carcinogenesis.