Checkpoint kinase inhibitor AZD7762 strongly sensitises urothelial carcinoma cells to gemcitabine.

Abstract

BACKGROUND:

More effective chemotherapies are urgently needed for bladder cancer, a major cause of morbidity and mortality worldwide. We therefore explored the efficacy of the combination of gemcitabine and AZD7762, a checkpoint kinase 1/2 (CHK1/2) inhibitor, for bladder cancer.

METHODS:

Viability, clonogenicity, cell cycle distribution and apoptosis were assessed in urothelial cancer cell lines and various non-malignant urothelial cells treated with gemcitabine and AZD7762. DNA damage was assessed by γH2A.X and 53-BP1 staining and checkpoint activation was followed by Western blotting. Pharmacological inhibition of CHK1 and CHK2 was compared to downregulation of either CHK1 or CHK2 using siRNAs.

RESULTS:

Combined use of gemcitabine and AZD7762 synergistically reduced urothelial carcinoma cell viability and colony formation relative to either single treatment. Non-malignant urothelial cells were substantially less sensitive to this drug combination. Gemcitabine plus AZD7762 inhibited cell cycle progression causing cell accumulation in S-phase. Moreover, the combination induced pronounced levels of apoptosis as indicated by an increase in the fraction of sub-G1 cells, in the levels of cleaved PARP, and in caspase 3/7 activity. Mechanistic investigations showed that AZD7762 treatment inhibited the repair of gemcitabine-induced double strand breaks by interference with CHK1, since siRNA-mediated depletion of CHK1 but not of CHK2 mimicked the effects of AZD7762.

CONCLUSIONS:

AZD7762 enhanced sensitivity of urothelial carcinoma cells to gemcitabine by inhibiting DNA repair and disturbing checkpoints. Combining gemcitabine with CHK1 inhibition holds promise for urothelial cancer therapy.

• Authors: Makoto Isono, Michèle J Hoffmann, Maria Pinkerneil, Akinori Sato, Martin Michaelis, Jindrich Cinatl Jr, Günter Niegisch, Wolfgang A Schulz
• Journal: Journal of experimental & clinical cancer research : CR (J Exp Clin Cancer Res) Vol. 36 Issue 1 Pg. 1 (01 03 2017) ISSN: 1756-9966 [Electronic] England
• PMID: 28049532 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 3-(carbamoylamino)-5-(3-fluorophenyl)-N-(3-piperidyl)thiophene-2-carboxamide
• Antimetabolites, Antineoplastic
• Protein Kinase Inhibitors
• RNA, Small Interfering
• Thiophenes
• Deoxycytidine
• Urea
• Poly(ADP-ribose) Polymerases
• Checkpoint Kinase 2
• CHEK1 protein, human
• CHEK2 protein, human
• Checkpoint Kinase 1
• Caspases
• Gemcitabine

Topics

• Antimetabolites, Antineoplastic (pharmacology)
• Carcinoma, Transitional Cell (drug therapy, genetics, metabolism)
• Caspases (metabolism)
• Cell Cycle (drug effects)
• Cell Line, Tumor
• Cell Survival (drug effects)
• Checkpoint Kinase 1 (genetics, metabolism)
• Checkpoint Kinase 2 (genetics, metabolism)
• DNA Damage
• Deoxycytidine (analogs & derivatives, pharmacology)
• Drug Screening Assays, Antitumor
• Drug Synergism
• Gene Expression Regulation, Neoplastic (drug effects)
• Humans
• Poly(ADP-ribose) Polymerases (metabolism)
• Protein Kinase Inhibitors (pharmacology)
• RNA, Small Interfering
• Thiophenes (pharmacology)
• Urea (analogs & derivatives, pharmacology)
• Urinary Bladder Neoplasms (drug therapy, genetics, metabolism)
• Gemcitabine