Insulin receptor overexpression in a human pre-B acute lymphocytic leukemia cell line with a t(1;19) chromosome translocation near the INSR locus.
Human pre-B acute lymphocytic leukemia (ALL) cell line 697 contains a disease-specific chromosomal translocation, t(1;19), near the insulin receptor locus (INSR). Insulin binding, insulin receptor kinase and cell surface immunofluorescence experiments all show that 697 cells express more surface insulin receptors than 207 cells, a line of pre-B ALL cells that lack the t(1;19). Northern blot analysis confirms that 697 cells have increased levels of mRNA for the insulin receptor. Gene dosage and in situ hybridization analysis indicate that only two copies of the INSR locus are present in 697 cells, one on the translocation chromosome and one on the normal chromosome 19. The results described here demonstrate that transcriptional up-regulation of the INSR locus is correlated with the t(1;19) translocation found in human pre-B ALL cell line 697.