Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
Nat Genet. 2011 Dec 25;44(2):165-9. doi: 10.1038/ng.1041.
We sequenced eight melanoma exomes to identify new somatic mutations in metastatic melanoma. Focusing on the mitogen-activated protein (MAP) kinase kinase kinase (MAP3K) family, we found that 24% of melanoma cell lines have mutations in the protein-coding regions of either MAP3K5 or MAP3K9. Structural modeling predicted that mutations in the kinase domain may affect the activity and regulation of these protein kinases. The position of the mutations and the loss of heterozygosity of MAP3K5 and MAP3K9 in 85% and 67% of melanoma samples, respectively, together suggest that the mutations are likely to be inactivating. In in vitro kinase assays, MAP3K5 I780F and MAP3K9 W333* variants had reduced kinase activity. Overexpression of MAP3K5 or MAP3K9 mutants in HEK293T cells reduced the phosphorylation of downstream MAP kinases. Attenuation of MAP3K9 function in melanoma cells using siRNA led to increased cell viability after temozolomide treatment, suggesting that decreased MAP3K pathway activity can lead to chemoresistance in melanoma.
我们对 8 个黑色素瘤外显子组进行测序，以鉴定转移性黑色素瘤中的新体细胞突变。我们专注于丝裂原活化蛋白激酶激酶激酶（MAP3K）家族，发现 24%的黑色素瘤细胞系在 MAP3K5 或 MAP3K9 的蛋白编码区域存在突变。结构建模预测激酶结构域的突变可能会影响这些蛋白激酶的活性和调节。突变的位置以及 MAP3K5 和 MAP3K9 的杂合性缺失分别在 85%和 67%的黑色素瘤样本中，这表明这些突变可能是失活的。在体外激酶实验中，MAP3K5 I780F 和 MAP3K9 W333* 变体的激酶活性降低。在 HEK293T 细胞中过度表达 MAP3K5 或 MAP3K9 突变体可降低下游 MAP 激酶的磷酸化水平。使用 siRNA 减弱黑色素瘤细胞中的 MAP3K9 功能会导致替莫唑胺治疗后细胞活力增加，这表明 MAP3K 通路活性降低可能导致黑色素瘤的化疗耐药性。
