title: Genetic amplification of the NOTCH modulator LNX2 upregulates the WNT/β-catenin pathway in colorectal cancer.
abstract: Chromosomal copy number alterations (aneuploidy) define the genomic landscape of most cancer cells, but identification of the oncogenic drivers behind these imbalances remains an unfinished task. In this study, we conducted a systematic analysis of colorectal carcinomas that integrated genomic copy number changes and gene expression profiles. This analysis revealed 44 highly overexpressed genes mapping to localized amplicons on chromosome 13, gains of which occur often in colorectal cancers (CRC). RNA interference (RNAi)-mediated silencing identified eight candidates whose loss-of-function reduced cell viability 20% or more in CRC cell lines. The functional space of the genes NUPL1, LNX2, POLR1D, POMP, SLC7A1, DIS3, KLF5, and GPR180 was established by global expression profiling after RNAi exposure. One candidate, LNX2, not previously known as an oncogene, was involved in regulating NOTCH signaling. Silencing LNX2 reduced NOTCH levels but also downregulated the transcription factor TCF7L2 and markedly reduced WNT signaling. LNX2 overexpression and chromosome 13 amplification therefore constitutively activates the WNT pathway, offering evidence of an aberrant NOTCH-WNT axis in CRC.
authors: Cancer Genomics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20893, USA. campsj@mail.nih.gov
authors: Jordi
authors: J
authors: Camps
authors: Jason J
authors: JJ
authors: Pitt
authors: Georg
authors: G
authors: Emons
authors: Amanda B
authors: AB
authors: Hummon
authors: Chanelle M
authors: CM
authors: Case
authors: Marian
authors: M
authors: Grade
authors: Tamara L
authors: TL
authors: Jones
authors: Quang T
authors: QT
authors: Nguyen
authors: B Michael
authors: BM
authors: Ghadimi
authors: Tim
authors: T
authors: Beissbarth
authors: Michael J
authors: MJ
authors: Difilippantonio
authors: Natasha J
authors: NJ
authors: Caplen
authors: Thomas
authors: T
authors: Ried
mesh_terms: D002352:Carrier Proteins / Q000502:physiology*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D055028:Comparative Genomic Hybridization; D005434:Flow Cytometry; D006801:Humans; D034622:RNA Interference; D051880:Receptors, Notch / Q000502:physiology*; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000502:physiology*; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D051880:Receptors, Notch; D051153:Wnt Proteins; D051176:beta Catenin; C570847:LNX2 protein, human