(644) Reparixin Slows Cancer Cell Migration and Proliferation in Human Head and Neck Cutaneous SCC

Introduction: Cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers worldwide with the highest disease incidence in the head and neck. Currently, surgery is the mainstay of therapy with addition of adjuvant therapies for aggressive disease. In recent years, there is growing interest in developing targeted treatments; a potential area to target is the tumor microenvironment. Recently, our lab has shown IL-8 is highly secreted by cSCCs, and the addition of recombinant IL-8 promotes cSCC cell proliferation and migration in vitro.

Methods: Two patient-derived head and neck cSCC (HNA07, HNA15) and an established human cSCC (A431) cell lines were cultured. Cytokine array was performed to confirm high expression of IL-8. To study cell proliferation, reparixin (IL-8 receptor inhibitor) was added and CellTiter-Glo viability assays were performed. Two migration assays were performed: for the scratch migration assay, cells were grown to confluency and uniform gaps were made in the cell monolayer. Reparixin was added and the cell-free gap was imaged in a live-imaging microscope. For the transwell migration assay, a monolayer of cells with reparixin was added to transwell inserts, which were fully submerged in media with a chemoattractant. Cells were allowed to migrate, stained with DAPI, and counted.

Results: In all 3 cell lines, IL-8 was highly expressed. The addition of reparixin significantly slowed the rate of gap closure on scratch migration assay and the rate of transwell cell migration when compared to the control. Reparixin had no effect on HNA07 cell viability at 12 and 24 hours, however significantly reduced viability at 48 hours; there was no effect on cell viability in A431 and HNA15 at all tested time points.

Conclusions: IL-8 is highly expressed by HNcSCC cells. In our in vitro model, inhibiting IL-8 signaling with reparixin significantly slowed cancer cell migration in all cell lines and cancer cell proliferation at a later timepoint in HNA07. Further investigation into the role of IL-8 within the tumor microenvironment may lead to a novel therapeutic approach for the treatment of cSCC.