title: Dissociation of cellular transformation from platelet-derived growth factor independence.
abstract: ST2-3T3, a spontaneously transformed BALB/c-3T3 cell line which does not require platelet-derived growth factor (PDGF) for growth, was fused to THO2, a PDGF-responsive non-transformed BALB/c-3T3 cell line, in order to learn whether transformation is expressed coordinately with PDGF independence. Hybrid cells were selected and grown in medium containing both HAT (hypoxanthine-aminopterin-thymidine) and ouabain; unfused cells of each parental type were killed in HAT-ouabain medium. Five independently isolated ST2-3T3xTHO2 hybrid cell lines were established and characterized for both transformation and PDGF responsiveness. All five were transformed, having a disorganized growth pattern and achieving a final cell density similar to that of ST2-3T3 cells. Two of these lines did not respond to a brief treatment with PDGF: the mitogen neither induced the synthesis of a PDGF-modulated lysosomal protein (termed MEP), nor stimulated the cells to enter the S phase; one line responded to PDGF by synthesizing both MEP and DNA, whereas two others synthesized MEP but not DNA. In contrast, four independently isolated cell lines obtained by fusing PDGF-responsive non-transformed BALB/c-3TC cells to the THO2 line were all PDGF-responsive for both MEP and DNA synthesis and were not transformed. It appears that PDGF independence is not required for the transformation of BALB/c-3T3 cells.
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002469:Cell Separation; D002472:Cell Transformation, Viral / Q000187:drug effects*; D003470:Culture Media; D004261:DNA Replication / Q000187:drug effects; D005434:Flow Cytometry; D006822:Hybrid Cells / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D014176:Protein Biosynthesis; D011506:Proteins
chemical_list: D003470:Culture Media; D010982:Platelet-Derived Growth Factor; D011506:Proteins; C018589:lysosomal proteins