Monticone Massimiliano, Biollo Emanuela, Maffei Massimo, Donadini Alessandra, Romeo Francesco, Storlazzi Clelia Tiziana, Giaretti Walter, Castagnola Patrizio
Centro Biotecnologie Avanzate, Genova, Italy.
Mol Cancer. 2008 Dec 16;7:92. doi: 10.1186/1476-4598-7-92.
KRAS and BRAF mutations appear of relevance in the genesis and progression of several solid tumor types but the co-occurrence and interaction of these mutations have not yet been fully elucidated. Using a microsatellite stable (MSS) colorectal cancer (CRC) cell line (Colo741) having mutated BRAF and KRASWT, we also aimed to investigate the KRAS-BRAF interaction. Gene expression profiles for control KRASWT, KRAS G12V and KRAS G12D transfected cells were obtained after cell clone selection and RT-PCR screening. Extensive qPCR was performed to confirm microarray data.
We found that the KRAS G12V state deregulated several genes associated to cell cycle, apoptosis and nitrogen metabolism. These findings indicated a reduced survival and proliferation with respect to the KRASWT state. The KRAS G12D state was, instead, characterized by several other distinct functional changes as for example those related to chromatin organization and cell-cell adhesion without affecting apoptosis related genes.
These data predict that the G12D mutation may be more likely selected in a BRAF mutated context. At the same time, the presence of the KRAS G12V mutation in the cells escaping apoptosis and inducing angiogenesis via IL8 may confer a more aggressive phenotype. The present results get along with the observations that CRCs with G12V are associated with a worse prognosis with respect to the WT and G12D states and may help identifying novel CRC pathways and biomarkers of clinical relevance.
KRAS和BRAF突变在几种实体瘤类型的发生和发展中似乎具有相关性，但这些突变的共现和相互作用尚未完全阐明。我们使用具有BRAF突变和野生型KRAS的微卫星稳定（MSS）结肠直肠癌（CRC）细胞系（Colo741），旨在研究KRAS - BRAF相互作用。在细胞克隆选择和RT - PCR筛选后，获得了野生型KRAS、KRAS G12V和KRAS G12D转染细胞的基因表达谱。进行了广泛的qPCR以确认微阵列数据。
我们发现KRAS G12V状态失调了几个与细胞周期、细胞凋亡和氮代谢相关的基因。这些发现表明相对于野生型KRAS状态，细胞存活和增殖减少。相反，KRAS G12D状态的特征是其他几个不同的功能变化，例如那些与染色质组织和细胞间粘附相关的变化，而不影响与细胞凋亡相关的基因。
这些数据预测在BRAF突变的背景下，G12D突变可能更易被选择。同时，在通过IL8逃避细胞凋亡并诱导血管生成的细胞中存在KRAS G12V突变可能赋予更具侵袭性的表型。目前的结果与以下观察结果一致，即具有G12V的结肠直肠癌相对于野生型和G12D状态预后更差，并且可能有助于识别新的临床相关的结肠直肠癌途径和生物标志物。
