Development and evaluation of human AP endonuclease inhibitors in melanoma and glioma cell lines

TY - JOUR

T1 - Development and evaluation of human AP endonuclease inhibitors in melanoma and glioma cell lines

AU - Mohammed, M Z

AU - Vyjayanti, V N

AU - Laughton, C A

AU - Dekker, L V

AU - Fischer, P M

AU - Wilson, D M

AU - Abbotts, R

AU - Shah, S

AU - Patel, P M

AU - Hickson, I D

AU - Madhusudan, S

PY - 2011/2/15

Y1 - 2011/2/15

N2 - Aims:Modulation of DNA base excision repair (BER) has the potential to enhance response to chemotherapy and improve outcomes in tumours such as melanoma and glioma. APE1, a critical protein in BER that processes potentially cytotoxic abasic sites (AP sites), is a promising new target in cancer. In the current study, we aimed to develop small molecule inhibitors of APE1 for cancer therapy.Methods:An industry-standard high throughput virtual screening strategy was adopted. The Sybyl8.0 (Tripos, St Louis, MO, USA) molecular modelling software suite was used to build inhibitor templates. Similarity searching strategies were then applied using ROCS 2.3 (Open Eye Scientific, Santa Fe, NM, USA) to extract pharmacophorically related subsets of compounds from a chemically diverse database of 2.6 million compounds. The compounds in these subsets were subjected to docking against the active site of the APE1 model, using the genetic algorithm-based programme GOLD2.7 (CCDC, Cambridge, UK). Predicted ligand poses were ranked on the basis of several scoring functions. The top virtual hits with promising pharmaceutical properties underwent detailed in vitro analyses using fluorescence-based APE1 cleavage assays and counter screened using endonuclease IV cleavage assays, fluorescence quenching assays and radiolabelled oligonucleotide assays. Biochemical APE1 inhibitors were then subjected to detailed cytotoxicity analyses.Results:Several specific APE1 inhibitors were isolated by this approach. The IC 50 for APE1 inhibition ranged between 30 nM and 50 M. We demonstrated that APE1 inhibitors lead to accumulation of AP sites in genomic DNA and potentiated the cytotoxicity of alkylating agents in melanoma and glioma cell lines.Conclusions:Our study provides evidence that APE1 is an emerging drug target and could have therapeutic application in patients with melanoma and glioma.

AB - Aims:Modulation of DNA base excision repair (BER) has the potential to enhance response to chemotherapy and improve outcomes in tumours such as melanoma and glioma. APE1, a critical protein in BER that processes potentially cytotoxic abasic sites (AP sites), is a promising new target in cancer. In the current study, we aimed to develop small molecule inhibitors of APE1 for cancer therapy.Methods:An industry-standard high throughput virtual screening strategy was adopted. The Sybyl8.0 (Tripos, St Louis, MO, USA) molecular modelling software suite was used to build inhibitor templates. Similarity searching strategies were then applied using ROCS 2.3 (Open Eye Scientific, Santa Fe, NM, USA) to extract pharmacophorically related subsets of compounds from a chemically diverse database of 2.6 million compounds. The compounds in these subsets were subjected to docking against the active site of the APE1 model, using the genetic algorithm-based programme GOLD2.7 (CCDC, Cambridge, UK). Predicted ligand poses were ranked on the basis of several scoring functions. The top virtual hits with promising pharmaceutical properties underwent detailed in vitro analyses using fluorescence-based APE1 cleavage assays and counter screened using endonuclease IV cleavage assays, fluorescence quenching assays and radiolabelled oligonucleotide assays. Biochemical APE1 inhibitors were then subjected to detailed cytotoxicity analyses.Results:Several specific APE1 inhibitors were isolated by this approach. The IC 50 for APE1 inhibition ranged between 30 nM and 50 M. We demonstrated that APE1 inhibitors lead to accumulation of AP sites in genomic DNA and potentiated the cytotoxicity of alkylating agents in melanoma and glioma cell lines.Conclusions:Our study provides evidence that APE1 is an emerging drug target and could have therapeutic application in patients with melanoma and glioma.

KW - Brain Neoplasms

KW - Cell Line, Tumor

KW - DNA-(Apurinic or Apyrimidinic Site) Lyase

KW - Drug Discovery

KW - Drug Evaluation, Preclinical

KW - Enzyme Inhibitors

KW - Glioma

KW - Hela Cells

KW - High-Throughput Screening Assays

KW - Humans

KW - Inhibitory Concentration 50

KW - Melanoma

KW - Models, Biological

KW - Models, Molecular

KW - Structure-Activity Relationship

U2 - 10.1038/sj.bjc.6606058

DO - 10.1038/sj.bjc.6606058

M3 - Journal article

C2 - 21266972

SN - 1744-3865

VL - 104

SP - 653

EP - 663

JO - British Journal of Cancer Management

JF - British Journal of Cancer Management

IS - 4

ER -