Development and biological evaluation of AzoBGNU: A novel hypoxia-activated DNA crosslinking prodrug with AGT-inhibitory activity

Liu, Qi; Wang, Xiaoli; Li, Jun; Wang, Jiaojiao; Sun, Guizhi; Zhang, Na; Zhao, Lu; Zhong, Rugang

doi:10.1016/j.biopha.2021.112338

Cited by 6 publications

(6 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The above results indicated that the formation of dG-dC cross-link induced by CENUs would ultimately be blocked by AGT owing to the repair of N 1, O 6 -EtG and its precursor O 6 -ClEtG. This is in accordance with the results of several cytotoxicity assays, in which CENUs exhibited considerably potent drug resistance to the AGT high-expressing cancer cells with IC 50 > 1000 μM. − Consequently, the application of AGT inhibitors is crucial for ensuring the anticancer efficacy of CENUs by eliminating AGT-mediated drug resistance.…”

Section: Resultssupporting

confidence: 76%

Mechanism of AGT-Mediated Repair of dG-dC Cross-Links in the Drug Resistance to Chloroethylnitrosoureas: Molecular Docking, MD Simulation, and ONIOM (QM/MM) Investigation

Wang,

Ren,

Sun

et al. 2024

J. Chem. Inf. Model.

Self Cite

View full text Add to dashboard Cite

Chloroethylnitrosoureas (CENUs) are important chemotherapies applied in the treatment of cancer. They exert anticancer activity by inducing DNA interstrand cross-links (ICLs) via the formation of two O 6 -alkylguanine intermediates, O 6chloroethylguanine (O 6 -ClEtG) and N1,O 6 -ethanoguanine (N1,O 6 -EtG). However, O 6 -alkylguanine-DNA alkyltransferase (AGT), a DNA-repair enzyme, can restore the O 6 -alkylguanine damages and thereby obstruct the formation of ICLs (dG-dC cross-link). In this study, the inhibitory mechanism of ICL formation was investigated to elucidate the drug resistance of CENUs mediated by AGT in detail. Based on the structures of the substrate-enzyme complexes obtained from docking and MD simulations, two ONIOM (QM/MM) models with different sizes of the QM region were constructed. The model with a larger QM region, which included the substrate (O 6 -ClEtG or N1,O 6 -EtG), a water molecule, and five residues (Tyr114, Cys145, His146, Lys165, and Glu172) in the active pocket of AGT, accurately described the repairing reaction and generated the results coinciding with the experimental outcomes. The repair process consists of two sequential steps: hydrogen transfer to form a thiolate anion on Cys145 and alkyl transfer from the O 6 site of guanine (the rate-limiting step). The repair of N1,O 6 -EtG was more favorable than that of O 6 -ClEtG from both kinetics and thermodynamics aspects. Moreover, the comparison of the repairing process with the formation of dG-dC cross-link and the inhibition of AGT by O 6 -benzylguanine (O 6 -BG) showed that the presence of AGT could effectively interrupt the formation of ICLs leading to drug resistance, and the inhibition of AGT by O 6 -BG that was energetically more favorable than the repair of O 6 -ClEtG could not prevent the repair of N1,O 6 -EtG. Therefore, it is necessary to completely eliminate AGT activity before CENUs medication to enhance the chemotherapeutic effectiveness. This work provides reasonable explanations for the supposed mechanism of AGT-mediated drug resistance of CENUs and will assist in the development of novel CENU chemotherapies and their medication strategies.

show abstract

Section: Resultssupporting

confidence: 76%

Mechanism of AGT-Mediated Repair of dG-dC Cross-Links in the Drug Resistance to Chloroethylnitrosoureas: Molecular Docking, MD Simulation, and ONIOM (QM/MM) Investigation

Wang,

Ren,

Sun

et al. 2024

J. Chem. Inf. Model.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In our previous study, an azobenzene-based combi-nitrosourea prodrug, named AzoBGNU, was synthesized to selectively sensitize the oxygen-deficient tumor cells to the chloroethylating agent by achieving hypoxia-targeting inhibition of AGT. As expected, AzoBGNU showed higher proliferation inhibition against DU145 cells with high levels of AGT expression than free nimustine under hypoxic conditions [ 10 ]. However, the in vivo application of the combi-molecular prodrugs might be limited by its poor solubility as a result of the complicated chemical modification [ 25 ].…”

Section: Introductionsupporting

confidence: 61%

“…The cell-cultured samples were fixed by 2.5% Karnovsky’s fixative overnight at 4 ℃ and dehydrated in a graded series of ethanol (0%, 30%, 50%, 75%, 95%, 100%). After that, the samples were critical-point dried and sputter-coated with gold before imaging with a SU3500 SEM (Hitachi, Tokyo, Japan) [ 10 ].…”

Section: Methodsmentioning

confidence: 99%

“…O 6 -Alkylguanine-DNA alkyltransferase (AGT), a DNA-repair enzyme, can restore the BCNU-induced DNA damage by transferring the alkyl groups from the O 6 -position of guanine to the cysteine 145 (Cys145) residue in the active site [ 8 , 9 ]. This repair of the O 6 -alkylated guanine blocks the formation of ICLs, resulting in resistance of cells to BCNU, especially in the tumor tissues with high expression levels of AGT [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A multi-functional hypoxia/esterase dual stimulus responsive and hyaluronic acid-based nanomicelle for targeting delivery of chloroethylnitrosouea

Li,

Ren,

et al. 2023

J Nanobiotechnol

Self Cite

View full text Add to dashboard Cite

Carmustine (BCNU), a vital type of chloroethylnitrosourea (CENU), inhibits tumor cells growth by inducing DNA damage at O6 position of guanine and eventually forming dG-dC interstrand cross-links (ICLs). However, the clinical application of BCNU is hindered to some extent by the absence of tumor selectivity, poor stability and O6-alkylguanine-DNA alkyltransferase (AGT) mediated drug resistance. In recent years, tumor microenvironment has been widely utilized for advanced drug delivery. In the light of the features of tumor microenvironment, we constructed a multifunctional hypoxia/esterase-degradable nanomicelle with AGT inhibitory activity named HACB NPs for tumor-targeting BCNU delivery and tumor sensitization. HACB NPs was self-assembled from hyaluronic acid azobenzene AGT inhibitor conjugates, in which O6-BG analog acted as an AGT inhibitor, azobenzene acted as a hypoxia-responsive linker and carboxylate ester bond acted as both an esterase-sensitive switch and a connector with hyaluronic acid (HA). The obtained HACB NPs possessed good stability, favorable biosafety and hypoxia/esterase-responsive drug-releasing ability. BCNU-loaded HACB/BCNU NPs exhibited superior cytotoxicity and apoptosis-inducing ability toward the human uterine cervix carcinoma HeLa cells compared with traditional combined medication of BCNU plus O6-BG. In vivo studies further demonstrated that after a selective accumulation in the tumor site, the micelles could respond to hypoxic tumor tissue for rapid drug release to an effective therapeutic dosage. Thus, this multifunctional stimulus-responsive nanocarrier could be a new promising strategy to enhance the anticancer efficacy and reduce the side effects of BCNU and other CENUs.

show abstract

“…The molecular mechanisms underlying azo dyes cytotoxicity in cancer cells has been extremely little studied. Qi Liu et al recently proved that azobenzene-based prodrug possesses desirable targeting ability against tumor-hypoxia and can eliminate chemoresistance when compared with the conventional chemotherapy drugs as chloroethylnitrosoureas ( Liu et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

The effect of Azo-dyes on glioblastoma cells in vitro

Sevastre

Baloi

Alexandru

et al. 2023

Saudi Journal of Biological Sciences

View full text Add to dashboard Cite

Development and biological evaluation of AzoBGNU: A novel hypoxia-activated DNA crosslinking prodrug with AGT-inhibitory activity

Cited by 6 publications

References 66 publications

Mechanism of AGT-Mediated Repair of dG-dC Cross-Links in the Drug Resistance to Chloroethylnitrosoureas: Molecular Docking, MD Simulation, and ONIOM (QM/MM) Investigation

Mechanism of AGT-Mediated Repair of dG-dC Cross-Links in the Drug Resistance to Chloroethylnitrosoureas: Molecular Docking, MD Simulation, and ONIOM (QM/MM) Investigation

A multi-functional hypoxia/esterase dual stimulus responsive and hyaluronic acid-based nanomicelle for targeting delivery of chloroethylnitrosouea

The effect of Azo-dyes on glioblastoma cells in vitro

Contact Info

Product

Resources

About