【摘要】 目的 探讨MerTK抑制剂UNC2250对黑素瘤小鼠肿瘤生长的影响，并初步阐明其作用机制。方法 将16只健康C57BL/6小鼠随机分为对照组及低、中、高剂量UNC2250治疗组，每组4只。构建黑素瘤皮下肿瘤模型后，对照组每日灌胃生理盐水，低、中、高剂量UNC2250治疗组分别给予25、50、75 mg/(kg·d) UNC2250灌胃，每日1次，连续干预20 d。监测小鼠肿瘤生长、瘤重及体质量变化。通过免疫荧光染色和流式细胞术检测肿瘤相关巨噬细胞(TAMs)的浸润情况，并在体外培养小鼠骨髓来源的巨噬细胞(BMDMs),利用IL-4诱导M2型巨噬细胞，采用RT-PCR检测UNC2250对巨噬细胞表型极化的影响。结果 UNC2250显著抑制黑素瘤小鼠的肿瘤生长，且呈剂量依赖性(F=298.50,均P<0.001)。与对照组相比，低、中、高剂量UNC2250治疗组小鼠的瘤重均显著降低(F=194.20,均P<0.001),肿瘤体积随剂量增加而减小。UNC2250对小鼠体质量无显著影响。肿瘤微环境中，UNC2250干预后，肿瘤组织中TAMs的浸润显著减少。进一步分析发现，TAMs中M1型巨噬细胞比例增多(F=31.95,对照组与低、中、高剂量组比较的P值分别为0.120、0.008、<0.001),而M2型巨噬细胞比例减少(F=45.27,对照组与低、中、高剂量组比较的P值分别为0.034、<0.001、<0.001)。体外实验结果显示，UNC2250能够抑制BMDMs向免疫抑制性M2表型极化，表现为M2型巨噬细胞标志物Arg1和Mgl1的mRNA表达水平显著下调。结论 MerTK抑制剂UNC2250呈剂量依赖性抑制黑素瘤小鼠肿瘤生长且安全性良好，其干预与肿瘤微环境中TAMs浸润减少、M1/M2型巨噬细胞表型转换相关。更多还原

【Abstract】 Objective To investigate the effect of the MerTK inhibitor UNC2250 on tumor growth in melanoma mice and to preliminarily elucidate its mechanism of action. Methods Sixteen healthy C57BL/6 mice were randomly divided into a control group and low-, medium-, and high-dose UNC2250 treatment groups, with 4 mice per group. After establishing a subcutaneous melanoma tumor model, the control group received daily oral gavage of saline, while the treatment groups were administered UNC2250 at doses of 25, 50 and 75 mg/(kg·d), respectively, once daily for 20 consecutive days. Tumor growth, tumor weight, and body weight changes were monitored. The infiltration of tumor-associated macrophages(TAMs) in the tumor microenvironment was detected by immunofluorescence staining and flow cytometry. Additionally, bone marrow-derived macrophages(BMDMs) were cultured in vitro, and M2 macrophages were induced using IL-4. RT-PCR was used to evaluate the effect of UNC2250 on macrophage phenotype polarization. Results UNC2250 significantly inhibited tumor growth in melanoma mice in a dose-dependent manner(F=298.50, all P<0.001). Compared with the control group, tumor weight in the low-, medium-, and high-dose UNC2250 treatment groups was significantly reduced(F=194.20, all P<0.001), and tumor volume decreased with increasing doses. UNC2250 had no significant effect on body weight. Within the tumor microenvironment, UNC2250 intervention markedly reduced the infiltration of TAMs. Further analysis showed an increased proportion of M1-type macrophages among TAMs(F=31.95, P-values for comparisons with control group were 0.120, 0.008, and <0.001 for low, medium, and high doses, respectively), and a decreased proportion of M2-type macrophages(F=45.27; P-values were 0.034, <0.001, and <0.001, respectively). In vitro experiment showed that UNC2250 inhibited the polarization of bone marrow-derived macrophages(BMDMs) toward the immunosuppressive M2 phenotype, as evidenced by significantly downregulated mRNA expression of M2 macrophage markers Arg1 and Mgl1. Conclusions The MerTK inhibitor UNC2250 suppresses tumor growth in melanoma mice in a dose-dependent manner with good safety, and its intervention is associated with reduced infiltration of tumor-associated macrophages(TAMs) and a shift in macrophage polarization from the M2 to M1 phenotype in the tumor microenvironment.更多还原