Absence of c-kit receptor and absent proliferative response to stem cell factor in childhood Burkitt's lymphoma cells.
The cytokine stem cell factor (SCF) synergizes with interleukin-7 (IL-7) to enhance the proliferation of pre-B cells. To examine the role of SCF and its receptor, c-kit, in the pathogenesis of pediatric Burkitt's lymphomas (BL), we investigated the expression of SCF and c-kit in BL cells and the mitogenic activity of SCF on BL cells. A panel of 13 BL cell lines and 7 fresh biopsy tumors was investigated. BL cells were stimulated either by Epstein-Barr virus (EBV) infection or by different reagents and cytokines, and expression of SCF and c-kit was studied on the mRNA level by Northern blot analysis and reverse-transcriptase polymerase chain reaction (RT-PCR), followed by Southern blotting. c-kit expression was also studied by fluorescence-activated cell sorting and by crosslinking of digoxigenin-labeled recombinant human SCF to the cell surface. Proliferation of BL cell lines was measured by 3H-thymidine incorporation. Low-level expression of c-kit mRNA was detected in 2 of 13 unstimulated BL cell lines and in 1 fresh BL tumor. One cell line showed upregulation of c-kit mRNA with A23187 and downregulation with phorbol myristate acetate. Neither c-kit nor SCF could be detected in any other cell line under any condition of stimulation as analyzed by Northern blot analysis, RT-PCR followed by Southern blot analysis, crosslinking, and immunofluorescence. No response to SCF was seen in 3H-thymidine incorporation assays. We conclude that most BL cells express neither SCF nor c-kit and that the low-level expression of c-kit in some BL cells most likely has no biologic significance.
Tomeczkowski
J
J
Department of Pediatric Hematology and Oncology, Medical School Hannover, Germany.
Beilken
A
A
Frick
D
D
Wieland
B
B
König
A
A
Falk
M H
MH
Reiter
A
A
Welte
K
K
Sykora
K W
KW
D000293:Adolescent; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006133:Growth Substances; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D019009:Proto-Oncogene Proteins c-kit; D012333:RNA, Messenger / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D016184:Receptors, Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D006133:Growth Substances; D016298:Hematopoietic Cell Growth Factors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016184:Receptors, Colony-Stimulating Factor; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases; D005634:Fructose-Bisphosphate Aldolase