Protein kinase C blockade inhibits differentiation of myeloid blasts into dendritic cells by calcium ionophore A23187.
Direct differentiation of myeloid leukemia blasts into antigen-presenting dendritic cells (DCs) for use as cellular vaccines is unique in that identification of tumor-specific antigens may not be necessary because the antigens should already be endogenously expressed. We hypothesized that signaling through protein kinase C (PKC) is required for differentiation of HL-60 promyeloblasts into DCs upon stimulation with calcium ionophore A23187. To demonstrate the inhibitory effect of PKC blockade, we pretreated HL-60 myeloid blasts with the protein kinase inhibitor bisindolylmaleimide I (Bis-1) for 24 hours and then treated the cells with calcium ionophore A23187 for an additional 24 hours. Controls consisted of HL-60 blasts treated with A23187, Bis-1 alone, or media. We noted that blasts cultured in media, Bis-1, or Bis-1 then A23187 did not develop the morphologic and phenotypic DC characteristics, up-regulate Rel B, or activate allogeneic T-cells. Our findings suggested that PKC blockade inhibits morphologic, phenotypic, and functional differentiation of HL-60 promyeloblasts into antigen-presenting DCs. Our findings supported the role of PKC as an obligatory pathway for calcium ionophore A23187-induced differentiation of HL-60 myeloblasts into antigen-presenting DCs.
Li
Qian
Q
Section of Hematology-Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
Ozer
Howard
H
Lindner
Inna
I
Lee
Kelvin P
KP
Kharfan-Dabaja
Mohamed A
MA
D000938:Antigen-Presenting Cells; D000001:Calcimycin / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D003713:Dendritic Cells / Q000166:cytology* / Q000276:immunology; D018922:HL-60 Cells; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods; D007211:Indoles / Q000494:pharmacology; D015470:Leukemia, Myeloid, Acute; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology*; D008301:Maleimides / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology; D051841:Transcription Factor RelB; D014157:Transcription Factors / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
D007211:Indoles; D008301:Maleimides; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D014157:Transcription Factors; D051841:Transcription Factor RelB; D000001:Calcimycin; D011493:Protein Kinase C; C070515:bisindolylmaleimide I