Although immunotherapy has achieved impressive durable clinical responses, many cancers respond only temporarily or not at all to immunotherapy.,To find novel, targetable mechanisms of resistance to immunotherapy, patient-derived melanoma cell lines were transduced with 576 open reading frames, or exposed to arrayed libraries of 850 bioactive compounds, prior to co-culture with autologous tumor-infiltrating lymphocytes (TILs).,The synergy between the targets and TILs to induce apoptosis, and the mechanisms of inhibiting resistance to TILs were interrogated.,Gene expression analyses were performed on tumor samples from patients undergoing immunotherapy for metastatic melanoma.,Finally, the effect of inhibiting the top targets on the efficacy of immunotherapy was investigated in multiple preclinical models.,Aurora kinase was identified as a mediator of melanoma cell resistance to T-cell-mediated cytotoxicity in both complementary screens.,Aurora kinase inhibitors were validated to synergize with T-cell-mediated cytotoxicity in vitro.,The Aurora kinase inhibition-mediated sensitivity to T-cell cytotoxicity was shown to be partially driven by p21-mediated induction of cellular senescence.,The expression levels of Aurora kinase and related proteins were inversely correlated with immune infiltration, response to immunotherapy and survival in melanoma patients.,Aurora kinase inhibition showed variable responses in combination with immunotherapy in vivo, suggesting its activity is modified by other factors in the tumor microenvironment.,These data suggest that Aurora kinase inhibition enhances T-cell cytotoxicity in vitro and can potentiate antitumor immunity in vivo in some but not all settings.,Further studies are required to determine the mechanism of primary resistance to this therapeutic intervention.,The online version of this article (10.1007/s00262-020-02748-9) contains supplementary material, which is available to authorized users.
Down-regulation of the immune system facilitates tumor progression at different stages of cutaneous melanoma.,Sentinel nodes, the first lymph nodes on lymphatics draining directly from a primary melanoma are immune down-regulated by tumor-generated immune-suppressive cytokines including interleukin-10.,To better understand the kinetics of sentinel node suppression, we investigated interleukin-10 expression by melanoma cells and tumor-associated macrophages and lymphocytes at different stages of primary melanoma evolution.,We used reverse transcriptase in situ polymerase chain reaction to identify cellular sources of interleukin-10 mRNA in 39 melanomas.,Interleukin-10 mRNA was identified in tumor cells of 2/6 melanomas in situ (33%), 17/21 invasive melanomas (81%) and 11/12 metastatic melanomas (92%).,Higher interleukin-10 expression correlates with tumor progression, with differences between melanoma in situ, invasive melanoma and metastatic melanoma.,In primary melanomas, the interleukin-10 mRNA content of tumor cells correlates with Clark level.,There was significantly more interleukin-10 mRNA in vertical growth phase melanoma cells than in radial growth phase cells.,In a logistic regression model, moderate to high interleukin-10 mRNA expression by tumor cells was significantly associated with vertical growth phase melanoma.,Interleukin-10 mRNA was detected in melanoma-associated macrophages and lymphocytes.,In invasive melanomas, the interleukin-10 mRNA reactivity of macrophages declined as Clark level increased.,Alterations of immunity by interleukin-10 derived from melanoma cells and melanoma-associated macrophages and lymphocytes potentially facilitate evolution of the primary melanoma and render regional lymph nodes susceptible to metastases.