CG7379/ING1 in cancer progression. A study of migration and invasion in in vivo and in vitro epithelial systems. CG7379/ING1 in cancer progression. A study of migration and invasion in in vivo and in vitro epithelial systems

Metastasis is the leading cause of death for cancer patients. Consequently it is imperative that we improve our understanding of the molecular mechanisms that underlie progression of tumour growth towards malignancy. A large-scale genetic screen was carried out to identify genes that affect tumour progression in the living fly. This screen identified CG7379 as promoting cancer cell invasion when gene expression was knocked down in epithelial tumours in the dorsal thorax of the fly. The uncharacterised CG7379 Drosophila gene shows high homology with the human ING (inhibitor of growth) gene family. ING proteins are known to be involved in the control of cell proliferation, senescence and apoptosis. However, their potential role in cell migration and invasion is yet to be properly documented. Homeostasis of epithelial tissues relies on the control of cell polarity and architecture, and our results strongly suggest that CG7379 and ING1 play an important role in cell-cell junction integrity maintenance. The knockdown of both the Drosophila and human gene increases invasion in the living animal and in in vitro invasion assays respectively and gene knock-down led to severe disruption of cell-cell junction integrity. We used Clariom™ S Assay arrays to detail the global programme of gene expression following ING1 KD to detect DEG involved in regulation of cell motility and cell-cell junction assembly and maintenance. Overall design: In order to assess the role of ING1 in invasion, ING1 was transiently knocked down by siRNA in MCF-7 cells 48h prior to RNA extraction and hybridization on Affymetrix microarrays. 3 independent experiments were performed, each including un-treated cells, cells treated with mock siRNA and cells treated with ING1 siRNA. The microarray analysis was further conducted in triplicate for each sample.

转移是癌症患者死亡的首要诱因。因此，加深对肿瘤向恶性表型进展背后的分子机制的理解，已是当务之急。本研究通过大规模遗传筛选，在活体果蝇体内鉴定出可影响肿瘤进展的基因。该筛选鉴定出CG7379：当在果蝇背侧胸部的上皮肿瘤中敲低该基因的表达时，其可促进癌细胞侵袭。功能尚未明确的果蝇CG7379基因，与人类ING（inhibitor of growth，生长抑制因子）基因家族具有高度同源性。已知ING蛋白参与调控细胞增殖、衰老与凋亡过程，但它们在细胞迁移与侵袭中潜在的作用尚未得到充分的研究证实。上皮组织的稳态依赖于细胞极性与结构的调控，本研究结果表明，CG7379与ING1在维持细胞间连接完整性方面发挥着重要作用。分别敲低果蝇与人类的该基因，可分别在活体动物与体外侵袭实验中增强侵袭能力；而基因敲低会严重破坏细胞间连接的完整性。本研究使用Clariom™ S检测芯片，对ING1敲低后的全局基因表达谱进行分析，以筛选参与调控细胞运动、细胞间连接组装与维持的差异表达基因（differentially expressed gene, DEG）。实验整体设计：为评估ING1在侵袭过程中的作用，本研究采用siRNA在MCF-7细胞中瞬时敲低ING1，于RNA提取及Affymetrix微阵列杂交前48小时完成转染。本研究共开展3次独立实验，每组均包含未处理细胞、阴性对照siRNA处理细胞与ING1 siRNA处理细胞三个组别；每个样本的微阵列分析均进行三次重复实验。