title: High-throughput RNAi screening for novel modulators of vimentin expression identifies MTHFD2 as a regulator of breast cancer cell migration and invasion.
abstract: Vimentin is an intermediate filament protein, with a key role in the epithelial to mesenchymal transition as well as cell invasion, and it is often upregulated during cancer progression. However, relatively little is known about its regulation in cancer cells. Here, we performed an RNA interference screen followed by protein lysate microarray analysis in bone metastatic MDA-MB-231(SA) breast cancer cells to identify novel regulators of vimentin expression. Out of the 596 genes investigated, three novel vimentin regulators EPHB4, WIPF2 and MTHFD2 were identified. The reduced vimentin expression in response to EPHB4, WIPF2 and MTHFD2 silencing was observed at mRNA and protein levels. Bioinformatic analysis of gene expression data across cancers indicated overexpression of EPHB4 and MTHFD2 in breast cancer and high expression associated with poor clinical characteristics. Analysis of 96 cDNA samples derived from both normal and malignant human tissues suggested putative association with metastatic disease. MTHFD2 knockdown resulted in impaired cell migration and invasion into extracellular matrix as well as decreased the fraction of cells with a high CD44 expression, a marker of cancer stem cells. Furthermore, MTHFD2 expression was induced in response to TGF-β stimulation in breast cancer cells. Our results show that MTHFD2 is overexpressed in breast cancer, associates with poor clinical characteristics and promotes cellular features connected with metastatic disease, thus implicating MTHFD2 as a potential drug target to block breast cancer cell migration and invasion.
authors.affiliation: Medical Biotechnology, VTT Technical Research Centre of Finland and Turku Centre for Biotechnology, University of Turku, Turku, Finland. lauleh@utu.fi
authors.forename: Laura
authors.initials: L
authors.lastname: Lehtinen
authors.forename: Kirsi
authors.initials: K
authors.lastname: Ketola
authors.forename: Rami
authors.initials: R
authors.lastname: Mäkelä
authors.forename: John-Patrick
authors.initials: JP
authors.lastname: Mpindi
authors.forename: Miro
authors.initials: M
authors.lastname: Viitala
authors.forename: Olli
authors.initials: O
authors.lastname: Kallioniemi
authors.forename: Kristiina
authors.initials: K
authors.lastname: Iljin
mesh_terms: D000619:Aminohydrolases / Q000235:genetics* / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP) / Q000235:genetics* / Q000378:metabolism; D008840:Microfilament Proteins; D018613:Microscopy, Confocal; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D034622:RNA Interference; D036224:Receptor, EphB4 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014746:Vimentin / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C497483:CD44 protein, human; D015820:Cadherins; D002352:Carrier Proteins; D018960:Hyaluronan Receptors; D008840:Microfilament Proteins; D009097:Multienzyme Complexes; D016212:Transforming Growth Factor beta; D014746:Vimentin; C465744:WIPF2 protein, human; C055342:methylene tetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP); D036224:Receptor, EphB4; D000619:Aminohydrolases