Elevated levels of peripheral blood and tumor tissue neutrophils are associated with poorer clinical response and therapy resistance in melanoma. The underlying mechanism and the role of neutrophils in targeted therapy is still not fully understood. Serum samples of patients with advanced melanoma were collected and neutrophil-associated serum markers were measured and correlated with response to targeted therapy. Blood neutrophils from healthy donors and patients with advanced melanoma were isolated, and their phenotypes, as well as their in vitro functions, were compared. In vitro functional tests were conducted through nonadherent cocultures with melanoma cells. Protection of melanoma cell lines by neutrophils was assessed under MAPK inhibition. Blood neutrophils from advanced melanoma patients exhibited lower CD16 expression compared to healthy donors. In vitro, both healthy-donor- and patient-derived neutrophils prevented melanoma cell apoptosis upon dual MAPK inhibition. The effect depended on cell–cell contact and melanoma cell susceptibility to treatment. Interference with protease activity of neutrophils prevented melanoma cell protection during treatment in cocultures. The negative correlation between neutrophils and melanoma outcomes seems to be linked to a protumoral function of neutrophils. In vitro, neutrophils exert a direct protective effect on melanoma cells during dual MAPK inhibition. This study further hints at a crucial role of neutrophil-related protease activity in protection.
外周血和肿瘤组织中中性粒细胞水平升高与黑色素瘤患者较差的临床反应和治疗抵抗相关。中性粒细胞在靶向治疗中的潜在作用机制尚未完全阐明。本研究收集晚期黑色素瘤患者血清样本，检测中性粒细胞相关血清标志物，并分析其与靶向治疗反应的相关性。同时分离健康供体与晚期黑色素瘤患者血液中的中性粒细胞，比较其表型特征及体外功能。通过非贴壁共培养体系进行体外功能实验，评估MAPK抑制条件下中性粒细胞对黑色素瘤细胞的保护作用。结果显示，晚期黑色素瘤患者血液中性粒细胞的CD16表达水平低于健康供体。体外实验中，无论是健康供体还是患者来源的中性粒细胞，均能在双重MAPK抑制条件下阻止黑色素瘤细胞凋亡。该保护效应依赖于细胞间直接接触以及黑色素瘤细胞对治疗的敏感性。干扰中性粒细胞的蛋白酶活性可消除共培养体系中黑色素瘤细胞在治疗期间获得的保护作用。中性粒细胞与黑色素瘤不良预后的负相关性可能与其促肿瘤功能相关。体外实验表明，在双重MAPK抑制条件下，中性粒细胞对黑色素瘤细胞具有直接保护作用。本研究进一步提示中性粒细胞相关蛋白酶活性在保护机制中起关键作用。
Susceptibility of Melanoma Cells to Targeted Therapy Correlates with Protection by Blood Neutrophils
肿瘤(癌症)患者之家