Carson Craig C, Moschos Stergios J, Edmiston Sharon N, Darr David B, Nikolaishvili-Feinberg Nana, Groben Pamela A, Zhou Xin, Kuan Pei Fen, Pandey Shaily, Chan Keefe T, Jordan Jamie L, Hao Honglin, Frank Jill S, Hopkinson Dennis A, Gibbs David C, Alldredge Virginia D, Parrish Eloise, Hanna Sara C, Berkowitz Paula, Rubenstein David S, Miller C Ryan, Bear James E, Ollila David W, Sharpless Norman E, Conway Kathleen, Thomas Nancy E
Department of Dermatology, The University of North Carolina, Chapel Hill, North Carolina.
Department of Medicine, The University of North Carolina, Chapel Hill, North Carolina. Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina.
Clin Cancer Res. 2015 May 1;21(9):2167-76. doi: 10.1158/1078-0432.CCR-14-1826.
IL2 inducible T-cell kinase (ITK) promoter CpG sites are hypomethylated in melanomas compared with nevi. The expression of ITK in melanomas, however, has not been established and requires elucidation.
An ITK-specific monoclonal antibody was used to probe sections from deidentified, formalin-fixed paraffin-embedded tumor blocks or cell line arrays and ITK was visualized by IHC. Levels of ITK protein differed among melanoma cell lines and representative lines were transduced with four different lentiviral constructs that each contained an shRNA designed to knockdown ITK mRNA levels. The effects of the selective ITK inhibitor BI 10N on cell lines and mouse models were also determined.
ITK protein expression increased with nevus to metastatic melanoma progression. In melanoma cell lines, genetic or pharmacologic inhibition of ITK decreased proliferation and migration and increased the percentage of cells in the G0-G1 phase. Treatment of melanoma-bearing mice with BI 10N reduced growth of ITK-expressing xenografts or established autochthonous (Tyr-Cre/Pten(null)/Braf(V600E)) melanomas.
We conclude that ITK, formerly considered an immune cell-specific protein, is aberrantly expressed in melanoma and promotes tumor development and progression. Our finding that ITK is aberrantly expressed in most metastatic melanomas suggests that inhibitors of ITK may be efficacious for melanoma treatment. The efficacy of a small-molecule ITK inhibitor in the Tyr-Cre/Pten(null)/Braf(V600E) mouse melanoma model supports this possibility.
与痣相比，白细胞介素 2 诱导型 T 细胞激酶（ITK）启动子 CpG 位点在黑色素瘤中呈低甲基化状态。然而，ITK 在黑色素瘤中的表达尚未明确，需要进一步阐明。
使用 ITK 特异性单克隆抗体检测来自身份不明的福尔马林固定石蜡包埋肿瘤块或细胞系阵列的切片，通过免疫组化观察 ITK。黑色素瘤细胞系中 ITK 蛋白水平存在差异，选用代表性细胞系用四种不同的慢病毒构建体进行转导，每个构建体都包含一个设计用于敲低 ITK mRNA 水平的短发夹 RNA。还测定了选择性 ITK 抑制剂 BI 10N 对细胞系和小鼠模型的影响。
随着从痣到转移性黑色素瘤的进展，ITK 蛋白表达增加。在黑色素瘤细胞系中，ITK 的基因或药物抑制降低了细胞增殖和迁移，并增加了处于 G0-G1 期的细胞百分比。用 BI 10N 处理荷黑色素瘤小鼠可减少表达 ITK 的异种移植瘤或已建立的原位（Tyr-Cre/Pten(null)/Braf(V600E)）黑色素瘤的生长。
我们得出结论，ITK 以前被认为是一种免疫细胞特异性蛋白，在黑色素瘤中异常表达并促进肿瘤发展和进展。我们发现 ITK 在大多数转移性黑色素瘤中异常表达，这表明 ITK 抑制剂可能对黑色素瘤治疗有效。小分子 ITK 抑制剂在 Tyr-Cre/Pten(null)/Braf(V600E)小鼠黑色素瘤模型中的疗效支持了这一可能性。
