Olaparib hydroxamic acid derivatives as dual PARP and HDAC inhibitors for cancer therapy

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Oncology

Background:

• Olaparib, a PARP inhibitor, is FDA-approved for BRCA-mutated ovarian cancer.
• Combining olaparib with HDAC inhibitors enhances anticancer effects.
• Rational drug design can create novel hybrid molecules targeting multiple pathways.

Purpose of the Study:

• To design and synthesize novel hydroxamic acid derivatives of olaparib as dual PARP and HDAC inhibitors.
• To evaluate the inhibitory activities and antiproliferative effects of these hybrid compounds.
• To investigate the underlying mechanisms of action for potential cancer therapy.

Main Methods:

• Synthesis of olaparib-based hydroxamic acid derivatives.
• In vitro enzymatic assays to determine IC50 values for PARP1/2 and HDAC1/6 inhibition.
• Antiproliferative assays in various human cancer cell lines and normal cells.
• Western blot analysis to assess protein expression and DNA damage markers.
• Flow cytometry to analyze apoptosis pathways.

Main Results:

• Synthesized hybrid compounds demonstrated potent inhibition of PARP1/2 and HDAC1/6 in the nanomolar range.
• Compound P1 exhibited broad-spectrum antiproliferative activity against cancer cell lines, outperforming olaparib and SAHA.
• P1 showed significantly lower cytotoxicity to normal cells compared to SAHA.
• Mechanism studies revealed P1 induces PARP cleavage, histone hyperacetylation, and DNA damage (γ-H2AX), while downregulating BRCA1 and RAD51.
• P1 modulates both mitochondrial and death receptor-mediated apoptosis pathways.

Conclusions:

• Novel dual PARP and HDAC inhibitors based on olaparib were successfully designed and synthesized.
• Compound P1 represents a promising therapeutic candidate with potent anticancer efficacy and improved safety profile.
• Concurrent targeting of PARP and HDAC pathways offers a viable strategy for developing effective cancer treatments.