GRANULOCYTE-COLONY-STIMULATING FACTOR-RECEPTOR EXPRESSION ON HUMAN TRANSITIONAL-CELL CARCINOMA OF THE BLADDER

Receptors for granulocyte colony-stimulating factor (G-CSFRs) have bee n confirmed on the cell surfaces of several nonhaematopoietic cell typ es, including bladder cancer cells. This observation has naturally led to the hypothesis that the expression of G-CSFR on these cells may en hance their growth by G-CSF. In this study, the expression of G-CSFR w as determined in both established human bladder cancer cell lines and primary bladder cancers. We studied five different human bladder cance r cell lines (KU-1, KU-7, T-24, NBT-2 and KK) and 26 newly diagnosed b ladder tumours. G-CSFR mRNA expressions on cultured cell lines were de termined using the reverse transcriptase polymerase chain reaction (RT -PCR) method. Furthermore, the G-CSFR binding experiments on the cultu red cell lines were conducted using the (NaI)-I-125-labelled G-CSF lig and-binding assay method. Moreover, the G-CSFR mRNA expressions on pri mary bladder tumour specimens were assessed using the in situ RT-PCR m ethod. Three out of the five cultured cell lines (KU-1, NBT-2 and KK) exhibited G-CSFR mRNA signals when the RT-PGR method was used. The G-C SFR binding experiments showed an equilibrium dissociation constant (K -d) of 490 pM for KU-1, 340 pM for NET-2 and 103 pM for KK cells. With in situ RT-PCR, the tumour cells of 6 out of 26 primary bladder tumou r specimens (23.1%) presented positive G-CSFR mRNA signals. Thus, in t his study, G-CSFR expression was frequently observed on bladder cancer cells. Therefore, the clinical use of G-CSF for patients with bladder cancer should be selected with great care.