c-myc expression correlates with suppression of c-kit protooncogene expression in small cell lung cancer cell lines.
The mRNAs encoding the c-kit protooncogene tyrosine kinase receptor and its ligand, hemopoietic stem cell factor, are coexpressed in the majority of small cell lung cancer cell lines, suggesting that an autocrine growth loop may exist. Functional c-kit protein levels correspond well with mRNA levels in these cells. We have observed that those cell lines which express the c-kit gene also express either the L- and N-myc genes; those cell lines which express the c-myc gene do not express the c-kit gene. We have determined, by analyzing several small lung cancer cell lines transfected with a c-myc expression vector, that heterologous expression of c-myc correlates with a marked down-regulation of c-kit expression. Regulation of c-kit expression by the myc gene family may be partly responsible for the differing biological properties of cell lines and tumors which express N- and L-myc versus those that express c-myc.
Plummer
H
H
Department of Medicine, Medical College of Virginia, Richmond.
Catlett
J
J
Leftwich
J
J
Armstrong
B
B
Carlson
P
P
Huff
T
T
Krystal
G
G
D018288:Carcinoma, Small Cell / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012334:RNA, Neoplasm / Q000032:analysis / Q000235:genetics; D019089:Stem Cell Factor; D014407:Tumor Cells, Cultured
D016298:Hematopoietic Cell Growth Factors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D019089:Stem Cell Factor; D019009:Proto-Oncogene Proteins c-kit