title: Cten is targeted by Kras signalling to regulate cell motility in the colon and pancreas.
abstract: CTEN/TNS4 is an oncogene in colorectal cancer (CRC) which enhances cell motility although the mechanism of Cten regulation is unknown. We found an association between high Cten expression and KRAS/BRAF mutation in a series of CRC cell lines (p = 0.03) and hypothesised that Kras may regulate Cten. To test this, Kras was knocked-down (using small interfering (si)RNA) in CRC cell lines SW620 and DLD1 (high Cten expressors and mutant for KRAS). In each cell line, Kras knockdown was mirrored by down-regulation of Cten Since Kras signals through Braf, we tested the effect of Kras knockdown in CRC cell line Colo205 (which shows high Cten expression and is mutant for BRAF but wild type for KRAS). Cten levels were unaffected by Kras knockdown whilst Braf knockdown resulted in reduced Cten expression suggesting that Kras signals via Braf to regulate Cten. Quantification of Cten mRNA and protein analysis following proteasome inhibition suggested that regulation was of Cten transcription. Kras knockdown inhibited cell motility. To test whether this could be mediated through Cten, SW620 cells were co-transfected with Kras specific siRNAs and a Cten expression vector. Restoring Cten expression was able to restore cell motility despite Kras knockdown (transwell migration and wounding assay, p<0.001 for both). Since KRAS is mutated in many cancers, we investigated whether this relationship could be demonstrated in other tumour models. The experiments were repeated in the pancreatic cancer cell lines Colo357 & PSN-1(both high Cten expressors and mutant for KRAS). In both cell lines, Kras was shown to regulate Cten and forced expression of Cten was able to rescue loss of cell motility following Kras knockdown in PSN-1 (transwell migration assay, p<0.001). We conclude that, in the colon and pancreas, Cten is a downstream target of Kras and may be a mechanism through which Kras regulates of cell motility.
authors.affiliation: Division of Pathology, Nottingham University, Nottingham, United Kingdom.
authors.forename: Saleh
authors.initials: S
authors.lastname: Al-Ghamdi
authors.forename: Abdulkader
authors.initials: A
authors.lastname: Albasri
authors.forename: Julien
authors.initials: J
authors.lastname: Cachat
authors.forename: Salih
authors.initials: S
authors.lastname: Ibrahem
authors.forename: Belal A
authors.initials: BA
authors.lastname: Muhammad
authors.forename: Darryl
authors.initials: D
authors.lastname: Jackson
authors.forename: Abdolrahman S
authors.initials: AS
authors.lastname: Nateri
authors.forename: Karin B
authors.initials: KB
authors.lastname: Kindle
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ilyas
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D002465:Cell Movement; D003106:Colon / Q000166:cytology / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005434:Flow Cytometry; D055785:Gene Knockdown Techniques; D011905:Genes, ras; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D000070876:Tensins
chemical_list: D008840:Microfilament Proteins; D034741:RNA, Small Interfering; C000603371:TNS4 protein, human; D000070876:Tensins