title: Proliferation of IL-6-independent multiple myeloma does not require the activity of extracellular signal-regulated kinases (ERK1/2).
abstract: The evolutionarily conserved Ras/Raf/MEK/ERK pathway is thought to be essential for proliferation of eukaryotic cells. The human multiple myeloma (MM) cell line 8226 encodes an activated K-ras allele and proliferates without requirement for the main MM growth and survival factor IL-6. Surprisingly, the addition of the MEK1/2 inhibitors PD98059 or U0126 to 8226 cultures at doses that block virtually all ERK1/2 activity had minimal effects on the rapid proliferation of this cell line. In contrast, proliferation of the IL-6-dependent MM cell line, ANBL-6 was blocked by PD98059. Levels of activated forms of the other classical MAP kinases (JNK and p38) were very low during MM cell proliferation and, therefore, do not substitute for the mitogenic activities normally regulated by ERK kinases. These data demonstrate that proliferation of 8226 cells does not require ERK1/2 activity, and suggest that IL-6-independent growth of MM may correlate with independence from a requirement for ERK activity. Other signal transduction pathways that appear to regulate cell cycle progression in these cells were examined.
authors.affiliation: Greenebaum Cancer Center, University of Maryland Medical System, Baltimore, Maryland 21201, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Robert G
authors.initials: RG
authors.lastname: Fenton
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D011905:Genes, ras; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000201:enzymology* / Q000235:genetics; D009570:Nitriles / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000903:Antibiotics, Antineoplastic; D002070:Butadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D015850:Interleukin-6; D009025:Morpholines; D009570:Nitriles; D011518:Proto-Oncogene Proteins; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D020123:Sirolimus