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Systematic inhibitor selectivity between PARP1 and PARP2 enzymes: Molecular implications for ovarian cancer
Xueqian Zuo1, Haibo Zhao1, Dan Li1
1Department of Gynaecology, Cangzhou People's Hospital Affiliated to Cangzhou Medical College, Cangzhou, China.
Abstract:
Human poly(ADP-ribose) polymerases (PARPs) are a class of nuclear enzymes involved in the pathogenesis of diverse gynecologic tumors. The PARP1 and PARP2 are the two most documented members in PARP family, which have been approved as the druggable targets of ovarian and cervical cancers. Selective targeting of the two enzymes with small-molecule inhibitors is a great challenge due to the high conservation in catalytic domain and active site. Here, we investigate the systematic selectivity profile of sophisticated PARP inhibitors between the two enzymes. Computational methods are used to model/optimize the complex structures of inhibitor ligands with PARP1/2 catalytic domains and then to estimate the theoretical Fenzymatic assays exhibit a good consistence with theoretical selectivity over six tested inhibitor samples (rc2 = 0.857). It is revealed that the inhibitor selectivity is conferred from the exquisite difference in the residue composition and structural architecture of both the local activity sites and the whole catalytic domains of the two enzymes. In particular, the TMZ50 and ME0328 show strong selectivity between PARP1 and PARP2, but only the former has a potent activity on the two enzymes, whereas the latter can only inhibit the enzymes moderately. These compounds can be considered as potential lead molecular entities to develop new specific PARP-selective inhibitor drugs for personalized therapy combating gynecologic cancers.
Insights
Researchers explored poly(ADP-ribose) polymerase (PARP) inhibitor selectivity between PARP1 and PARP2 enzymes. Computational modeling and enzymatic assays identified specific inhibitors like TMZ50 and ME0328 for gynecologic cancer therapy.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- Human poly(ADP-ribose) polymerases (PARPs) are key nuclear enzymes implicated in gynecologic tumor development.
- PARP1 and PARP2 are validated drug targets for ovarian and cervical cancers, but selective inhibition is challenging due to conserved active sites.
Purpose of the Study:
- To systematically investigate the selectivity profiles of PARP inhibitors between PARP1 and PARP2.
- To identify novel small-molecule inhibitors with high selectivity for potential use in gynecologic cancer treatment.
Main Methods:
- Utilized computational methods to model and optimize inhibitor-PARP1/2 catalytic domain complexes.
- Estimated theoretical selectivity and validated findings with in vitro enzymatic assays.
- Analyzed structural differences in catalytic domains and active sites conferring selectivity.
Main Results:
- Computational predictions showed good correlation with experimental selectivity data (rc2 = 0.857).
- Identified significant structural and residue composition differences between PARP1 and PARP2 active sites and catalytic domains.
- TMZ50 and ME0328 demonstrated strong selectivity; TMZ50 exhibited potent activity, while ME0328 showed moderate inhibition.
Conclusions:
- Inhibitor selectivity is driven by subtle structural variations between PARP1 and PARP2.
- TMZ50 and ME0328 represent promising lead compounds for developing PARP-selective drugs.
- These selective inhibitors could advance personalized therapy strategies for gynecologic cancers.
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