Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States of America.
Department of Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Health Science Campus, Toledo, OH, United States of America.
PLoS One. 2019 Apr 17;14(4):e0204387. doi: 10.1371/journal.pone.0204387. eCollection 2019.
Recent high-throughput-sequencing of cancer genomes has identified oncogenic mutations in the B-Raf genetic locus as one of the critical events in melanomagenesis. B-Raf encodes a serine/threonine kinase that regulates the MAPK/ERK kinase (MEK) and extracellular signal-regulated kinase (ERK) protein kinase cascade. In normal cells, the activity of B-Raf is tightly regulated and is required for cell growth and survival. B-Raf gain-of-function mutations in melanoma frequently lead to unrestrained growth, enhanced cell invasion and increased viability of cancer cells. Although it is clear that the invasive phenotypes of B-Raf mutated melanoma cells are stringently dependent on B-Raf-MEK-ERK activation, the downstream effector targets that are required for oncogenic B-Raf-mediated melanomagenesis are not well defined. miRNAs have regulatory functions towards the expression of genes that are important in carcinogenesis. We observed that miR-10b expression correlates with the presence of the oncogenic B-Raf (B-RafV600E) mutation in melanoma cells. While expression of miR-10b enhances anchorage-independent growth of B-Raf wild-type melanoma cells, miR-10b silencing decreases B-RafV600E cancer cell invasion in vitro. Importantly, the expression of miR-10b is required for B-RafV600E-mediated anchorage independent growth and invasion of melanoma cells in vitro. Taken together our results suggest that miR-10b is an important mediator of oncogenic B-RafV600E activity in melanoma.
最近对癌症基因组的高通量测序已经确定，B-Raf 基因座中的致癌突变是黑色素瘤发生过程中的关键事件之一。B-Raf 编码一种丝氨酸/苏氨酸激酶，它调节 MAPK/ERK 激酶（MEK）和细胞外信号调节激酶（ERK）蛋白激酶级联。在正常细胞中，B-Raf 的活性受到严格调控，是细胞生长和存活所必需的。黑色素瘤中的 B-Raf 功能获得性突变常导致不受控制的生长、增强的细胞侵袭和癌细胞活力增加。尽管很明显，B-Raf 突变黑色素瘤细胞的侵袭表型严格依赖于 B-Raf-MEK-ERK 激活，但对于致癌性 B-Raf 介导的黑色素瘤发生所需的下游效应靶标尚未明确定义。miRNAs 对在致癌作用中重要的基因的表达具有调节功能。我们观察到 miR-10b 的表达与黑色素瘤细胞中致癌性 B-Raf（B-RafV600E）突变的存在相关。虽然 miR-10b 的表达增强了 B-Raf 野生型黑色素瘤细胞的无锚定生长，但 miR-10b 的沉默减少了 B-RafV600E 癌细胞在体外的侵袭。重要的是，miR-10b 的表达是 B-RafV600E 介导的黑色素瘤细胞体外无锚定生长和侵袭所必需的。综上所述，我们的研究结果表明，miR-10b 是黑色素瘤中致癌性 B-RafV600E 活性的重要介质。
