title: Phenotypic changes associated with DYNACTIN-2 (DCTN2) over expression characterise SJSA-1 osteosarcoma cells.
abstract: DYNACTIN-2 (DCTN2) localises to chromosome 12q13-q15, a region prone to stable amplification in several cancers. Transient DCTN2 overexpression has a significant impact on cellular phenotype primarily due to disruption of the DYNEIN-dynactin motor. Changes reported include alterations of microtubule-directed movement of molecular (e.g. TP53) and organelle (e.g. Golgi) cargoes towards the nucleus, centrosome biology, cellular movement and mitosis with a potential predisposition to mitotic block and polyploidy. These changes would be expected to be of relevance to carcinogenesis. To investigate this, we report the first study of DCTN2 genomic amplification and sustained DCTN2 overexpression in cancer cells. QFMPCR was employed to characterise the extent of chromosome 12q13-q15 amplicons in SJSA-1, SJRH30, U373MG and CCF-STTG1 cancer cells. DCTN2 amplification was present in SJSA-1, U373MG and SJRH30 cells, yet was incomplete at the 5'-end in SJRH30 cells. Only SJSA-1 cells were characterised by DCTN2 overexpression on Western blot analyses. Microscopy studies distinguished SJSA-1 cells by greater DCTN2 immunofluorescence and diminished centrosome and 58K protein Golgi-marker focus compared to SJRH30 cells. Indirect evidence derived from the published work of others indicated that TP53 transport into the nucleus was unimpaired. Furthermore, we observed that SJSA-1 cells were easy to propagate. In conclusion, persistent DCTN2 overexpression can be tolerated in SJSA-1 cancer cells despite phenotypic abnormalities predicted from transient overexpression studies. This preliminary study does not support a major role for DCTN2 overexpression in carcinogenesis, although further studies would be necessary to confirm this.
authors.affiliation: Molecular Medicine Unit, The University of Leeds, St. James's University Hospital, Leeds, United Kingdom.
authors.forename: Kieran L
authors.initials: KL
authors.lastname: Bransfield
authors.forename: Jon M
authors.initials: JM
authors.lastname: Askham
authors.forename: Jack P
authors.initials: JP
authors.lastname: Leek
authors.forename: Philip A
authors.initials: PA
authors.lastname: Robinson
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Mighell
mesh_terms: D000230:Adenocarcinoma; D001859:Bone Neoplasms / Q000235:genetics; D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D000072159:Dynactin Complex; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D012516:Osteosarcoma / Q000235:genetics; D010641:Phenotype; D012004:Rectal Neoplasms
chemical_list: C000606361:DCTN2 protein, human; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins