Autocrine Growth of Transitional Cell Carcinoma of the Bladder Induced by Granulocyte-Colony Stimulating Factor
Cancer Research. 55(15):3438-3443.
- Abstract
- Granulocyte-colony stimulating factor (G-CSF) produced by nonhematopoietic malignant cells has been reported to be capable of inducing a leukemoid reaction in the host through intense stimulation of leukocyte production. Furthermore, this is frequently associated with aggressive tumor cell growth and a detrimental clinical outcome. In this study, we identified bladder cancer cells producing G-CSF with the expression of the functional receptor, which provides direct evidence of autocrine growth of bladder cancer cells induced by G-CSF. The cancer cells used in this study were obtained from a 76-year-old man who had a metastatic transitional cell carcinoma of the bladder and who demonstrated marked leukocytosis; his peripheral blood leukocyte count was 94,900 leukocytes/ mm3, and his serum G-CSF level was 103 pg/ml. The culture medium in which the cancer cells were grown exclusively contained a significant amount of G-CSF (5560 pg/ml). Significant G-CSF inKN A expression and G-CSF receptor mRNA expression in the cultured cells were demon strated by the reverse transcription-PCR method. In addition, binding studies with the use of radiolabeled recombinant G-CSF demonstrated the presence of high-affinity G-CSF binding receptors on the cultured cancer cells. Finally, the proliferation of the cultured cancer cells was stimulated by exogenous G-CSF administration, and this stimulation was inhibited by adding anti-G-CSF antibody, as demonstrated by both the flow cytometric bromodeoxyuridine incorporation technique and the | 'lI |lh\miilinc incor poration assay. These results strongly suggest that G-CSF production by the bladder cancer cells studied augments autocrine growth. Therefore, we recommend exercising caution in the clinical use of G-CSF for bladder cancer patients.
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