FGFR3 is expressed and is important for survival in INA-6, a human myeloma cell line without a t(4;14)

• Published in: European journal of haematology 2009-11, Vol.83 (5), p.471-476
• Main Authors: Våtsveen, Thea K., Brenne, Anne-Tove, Dai, Hong Y., Waage, Anders, Sundan, Anders, Børset, Magne
• Format: Article
• Language: English
• Subjects: 14; Cell Line, Tumor; Cell Proliferation; Cell Survival - genetics; Chromosomes, Human, Pair 14; Chromosomes, Human, Pair 4; fibroblast growth factor receptor 3; Gene Dosage - genetics; Gene Expression Regulation, Neoplastic; Humans; IH-1; In Situ Hybridization, Fluorescence; INA-6; Multiple Myeloma - genetics; Multiple Myeloma - metabolism; Multiple Myeloma - pathology; multiple myeloma SET-domain; OH-2; PD173074; Quantitative Trait Loci - genetics; Receptor, Fibroblast Growth Factor, Type 3 - biosynthesis; Receptor, Fibroblast Growth Factor, Type 3 - genetics; Reverse Transcriptase Polymerase Chain Reaction; SU5402; t(4; 14); Translocation, Genetic
• ISSN: 0902-4441; 1600-0609
• DOI: 10.1111/j.1600-0609.2009.01312.x

Objectives:  Fibroblast growth factor receptor 3 (FGFR3) is a proto‐oncogene that is often dysregulated together with multiple myeloma SET‐domain (MMSET) by the immunoglobulin heavy chain (IGH) gene in t(4;14)pos multiple myeloma (MM) cells, and which is usually not expressed in MM cells without this translocation. Whether FGFR3 may play a role in MM cells without t(4;14) and the IGH‐MMSET fusion protein is unclear and is the focus of this report. Methods:  FGFR3 expression was explored in cell lines with and without t(4;14) by fluorescence in situ hybridization (FISH), RT‐PCR and Western Blot. FGFR3 inhibitors SU5402 and PD173074 were used to explore the role of FGFR3 in these cells. Results:  We discovered an amplification of the FGFR3 locus in INA‐6, a human MM cell line. We also demonstrated expression of FGFR3 mRNA and protein in the cells, probably caused by the extra copy of the gene. INA‐6 cells did not have t(4;14) and neither was there any involvement of the other IG loci in translocations with the FGFR3 gene. The FGFR3 inhibitors decreased the proliferation of INA‐6. Conclusion:  The decreased viability and proliferation in INA‐6, following inhibition with FGFR3 inhibitors, indicates that FGFR3 may play a role also in cells without t(4;14) – and hence without high expression of MMSET, the ubiquitous oncoprotein in MM cells with t(4;14). This gives further credibility to the notion that FGFR3 expression is not just an epiphenomenon in t(4;14) MM, but an important part of the malignant phenotype.