Inhibition of PKCalpha activation in human bone and soft tissue sarcoma cells by the selective PKC inhibitor PKC412.
BACKGROUND
PKC412, formerly CGP41251, N-benzoylstaurosporine, was initially developed as a selective protein kinase C (PKC) inhibitor, and it preferentially inhibits conventional PKC family members. In this study, the expression of PKCa was examined in human osteosarcoma and MFH cell lines, and the inhibitory effect of PKC412 on the proliferation of the cell lines was evaluated.


METHODS
Three human osteosarcoma cell lines (KTHOS, MG63 and KHOS) and four human MFH cell lines (TNMY1, GBS-1, Nara-F and Nara-H) were used. The expression of PKCalpha and phosphorylated PKCalpha were analyzed using both Western blotting analysis and immunocytochemical analysis. The effect of PKC412 on cell proliferation was evaluated using the MTS assay technique.


RESULTS
PKC412 inhibited cell proliferation of all seven cell lines in a dose- and time-dependent manner. Both Western blotting analysis and immunocytochemical analysis revealed that not only PKCalpha but also phosphorylated PKCalpha were expressed in all cell lines incubated with the culture medium without any stimuli. PKC412 suppressed phosphorylation of PKCalpha in all cell lines at a concentration of 1 microM.


CONCLUSIONS
The inhibition of cell proliferation of the human osteosarcoma and MFH cell lines by PKC412 might be due to reduced PKCalpha activity. This suggests PKC412 might be a potent chemotherapeutic agent for human sarcomas.
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Chuo-ku, Kobe, Hyogo, Japan.
Teruya
T
Kawamoto
Toshihiro
T
Akisue
Kenta
K
Kishimoto
Hitomi
H
Hara
Masaya
M
Imabori
Takuya
T
Fujimoto
Masahiro
M
Kurosaka
Toshiaki
T
Hitora
Yoji
Y
Kawaguchi
Tetsuji
T
Yamamoto
D001859:Bone Neoplasms / Q000201:enzymology* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D012509:Sarcoma / Q000201:enzymology* / Q000473:pathology; D019311:Staurosporine / Q000031:analogs & derivatives* / Q000494:pharmacology
D047428:Protein Kinase Inhibitors; D011493:Protein Kinase C; D019311:Staurosporine; C059539:midostaurin