Antitumor activity of UCN-01 in carcinomas of the head and neck is associated with altered expression of cyclin D3 and p27(KIP1).
Altered and deregulated cyclin-dependent kinase (cdk) activity is now believed to play a major role in the pathogenesis of head and neck squamous cell carcinomas (HNSCC), thus providing a suitable cellular target for therapeutic intervention. UCN-01 (7-hydroxy-staurosporine), a known protein kinase C and cdk modulator, demonstrates antiproliferative and antitumor properties in many experimental tumor models and may represent a potential candidate to test in HNSCC. In this study, UCN-01 displayed potent antiproliferative properties (IC50 of approximately 17-80 nM) in HNSCC cells. Cell cycle analysis revealed that UCN-01 treatment of HNSCC cells for 24 h leads to a G1 block with a concomitant loss of cells in S and G2-M and the emerging sub-G1 cell population, confirmed to be apoptotic by terminal deoxynucleotidyl transferase-mediated nick end labeling analysis. Additional in vitro studies demonstrated a G1 arrest that was preceded by depletion in cyclin D3, elevation of p21(WAF1) and p27(KIP1) leading to a loss in activity of G1 cdks (cdk2, cdk4), and reduction in pRb phosphorylation. Antitumor properties of UCN-01 were also assessed in vivo by treating HN12 xenografts (7.5 mg/kg/i.p./daily) with UCN-01 for 5 consecutive days. Total sustained abolition of tumor growth (P < 0.00001) was obtained with only one cycle of UCN-01 treatment. Terminal deoxynucleotidyl transferase-mediated nick end labeling staining of xenograft samples revealed a higher incidence of apoptosis in treated tissues when compared with control. Additional tissue analysis demonstrated that elevated p27(KIP1) with minimal increase in p21(WAF1) and reduced cyclin D3 levels were readily detected in those animals treated with UCN-01, similar to those observed in HNSCC cells. Thus, UCN-01 exhibits both in vitro and in vivo antitumor properties in HNSCC models, and these effects are associated with a decrease in cyclin D3 and an increase in p27(KIP1) protein levels, thus providing appropriate surrogate markers to follow treatment efficacy in vivo and, therefore, a suitable drug candidate for treating HNSCC patients.
Patel
Vyomesh
V
Oral & Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
Lahusen
Tyler
T
Leethanakul
Chidchanok
C
Igishi
Tadashi
T
Kremer
Marcus
M
Quintanilla-Martinez
Leticia
L
Ensley
John F
JF
Sausville
Edward A
EA
Gutkind
J Silvio
JS
Senderowicz
Adrian M
AM
D016475:3T3 Cells; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D042846:CDC2-CDC28 Kinases; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D056743:Cyclin D3; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000096:biosynthesis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D016193:G1 Phase; D006258:Head and Neck Neoplasms / Q000188:drug therapy*; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D020128:Inhibitory Concentration 50; D007700:Kinetics; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011379:Prognosis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D016196:S Phase; D019311:Staurosporine / Q000031:analogs & derivatives; D013997:Time Factors; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis*
D000470:Alkaloids; D000970:Antineoplastic Agents; C534696:CCND3 protein, human; C493956:CDKN1A protein, human; C534697:Ccnd3 protein, mouse; C493957:Cdkn1a protein, mouse; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D056743:Cyclin D3; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; C054852:7-hydroxystaurosporine; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; C495893:Cdk2 protein, mouse; C495902:Cdk4 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D019311:Staurosporine