title: Differential expression of filamin B splice variants in giant cell tumor cells.
abstract: Giant cell tumor of bone (GCT) is the most commonly reported non-malignant bone tumor in Hong Kong. This kind of tumor usually affects people aged 20-40 years. Also, it is well known for recurrence locally, especially when the tumor cannot be removed completely. Filamins are actin-binding proteins which contain three family members, filamin A, B and C. They are the products of three different genes, FLNA, FLNB and FLNC, which can generate various transcript variants in different cell types. In this study, we focused on the effects of FLNBv2 and FLNBv4 toward GCT cells. The only difference between FLNBv2 and FLNBv4 is that FLNBv4 does not contain hinge 1 region. We found that the relative abundance of FLNBv4 varies among different GCT cell lines while the expression level of FLNBv4 in normal osteoblasts was only marginally detectable. In the functional aspect, overexpression of FLNBv4 led to upregulation of RANKL, OCN, OPG and RUNX2, which are closely related to GCT cell survival and differentiation. Moreover, FLNBv4 can have a negative effect on cell viability of GCT cells when compare with FLNBv2. In conclusion, splicing variants of FLNB are differentially expressed in GCT cells and may play a role in the proliferation and differentiation of tumor cells.
authors: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Joseph Chi-Ching
authors: JC
authors: Tsui
authors: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Carol Po-Ying
authors: CP
authors: Lau
authors: School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Alex Chun
authors: AC
authors: Cheung
authors: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Kwok-Chuen
authors: KC
authors: Wong
authors: Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Lin
authors: L
authors: Huang
authors: School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Stephen Kwok-Wing
authors: SK
authors: Tsui
authors: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, P.R. China.
authors: Shekhar Madhukar
authors: SM
authors: Kumta
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism*; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D005260:Female; D064448:Filamins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D018212:Giant Cell Tumor of Bone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D050659:Core Binding Factor Alpha 1 Subunit; D064448:Filamins; D020033:Protein Isoforms; C493709:RUNX2 protein, human