1Vimentin, a type III intermediate filament, is highly expressed in aggressive epithelial 2 cancers and is associated with increased rates of metastasis. We show that vimentin is causally 3 required for lung cancer metastasis using a genetic mouse model of lung adenocarcinoma (LSL-4 Kras G12D ;Tp53 fl/fl , termed KPV +/+ ) crossed with vimentin-null mice (thereby creating KPV −/− mice).
5Both KPV +/+ and KPV −/− mice developed lung tumors, yet KPV −/− mice had delayed tumorigenesis 6 and prolonged survival. KPV +/+ cells implanted in the flank metastasized to the lung while KPV −/− 7 cells did not, providing additional evidence that vimentin is required for metastasis. Differential 8 expression analysis of RNA-seq data demonstrated that KPV −/− cells had suppressed expression 9 of genes that drive epithelial-to-mesenchymal transition, migration, and invasion, processes that 10 are critical to the metastatic cascade. Integrative metabolomic and transcriptomic analysis 11 revealed altered glutaminolysis, with KPV −/− cells accumulating glutathione, leading to impaired 12 cell motility in response to oxidative stress. Together, these results show that loss of vimentin 13 impairs epithelial-to-mesenchymal transition and regulation of the oxidative stress response, 14 resulting in decreased metastasis in murine lung adenocarcinoma. 15 16 17 18Non-small-cell lung cancers (NSCLCs) represent 80% of all lung cancers and are often 20 diagnosed at more advanced stages of the disease resulting in high rates of mortality (1).
21Adenocarcinoma is the most common subtype of NSCLC and is characterized by activating 22 mutations in the Kras proto-oncogene in up to 30% of diagnoses and by inactivating mutations in 23 the tumor suppressor gene Tp53 in up to 60% of diagnoses (2)(3)(4)(5). Despite the prevalence of lung 24 adenocarcinoma, the metastatic mechanisms that drive lung cancer progression are incompletely 25 understood.
26The type III intermediate filament vimentin is associated with increased metastatic spread 27 and lower rates of survival in patients with NSCLC (6-8). Vimentin is a canonical marker of 28 epithelial-to-mesenchymal transition (EMT), an initiating event of the metastatic cascade (9). EMT 29 is the process by which epithelial cells remodel cell-cell and cell-extracellular-matrix (ECM) 30 contacts, lose their apical-basal polarity, and adopt the spindle-shaped morphology associated 31 with a mesenchymal cell phenotype (10). During EMT, cells undergo a downregulation of 32 epithelial cell associated genes, including E-cadherin and cytokeratins, and an upregulation of 33 mesenchymal cell associated genes, including N-cadherin and vimentin. In addition to acting as 34 a marker of EMT, vimentin is functionally involved in EMT. Structurally, vimentin intermediate 35 filaments control cell shape, and thus facilitate the transition toward a mesenchymal phenotype
36(11). Twist1, a transcription factor critical to EMT, upregulates vimentin expression (12). Vimentin 37 also serves as a scaffold for Slug, another transc...