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Therapeutic Targeting of P53: A Comparative Analysis of APR-246 and COTI-2 in Human Tumor Primary Culture 3-D
Adam J Nagourney1, Joshua B Gipoor1, Steven S Evans1
1Nagourney Cancer Institute, 750 E. 29th Street, Long Beach, CA 90806, USA.
Abstract:
Background:TP53 is the most commonly mutated gene in human cancer with loss of function mutations largely concentrated in "hotspots" affecting DNA binding. APR-246 and COTI-2 are small molecules under investigation in P53 mutated cancers. APR binds to P53 cysteine residues, altering conformation, while COTI-2 showed activity in P53 mutant tumors by a computational platform. We compared APR-246 and COTI-2 activity in human tumor explants from 247 surgical specimens. Methods: Ex vivo analyses of programmed cell death measured drug-induced cell death by delayed-loss-of-membrane integrity and ATP content. The LC50s were compared by Z-Score. Synergy was conducted by the method of Chou and Talalay, and correlations were performed by Pearson moment. Results: APR-246 and COTI-2 activity favored hematologic neoplasms, but solid tumor activity varied by diagnosis. COTI-2 and APR-246 activity did not correlate (R = 0.1028) (NS). COTI-2 activity correlated with nitrogen mustard, cisplatin and gemcitabine, doxorubicin and selumetinib, with a trend for APR-246 with doxorubicin. For ovarian cancer, COTI-2 showed synergy with cisplatin at 25%. Conclusions: COTI-2 and APR-246 activity differ by diagnosis. A lack of correlation supports distinct modes of action. Cisplatin synergy is consistent with P53's role in DNA damage. Different mechanisms of action may underlie disease specificity and offer better disease targeting.
Insights
The small molecules APR-246 and COTI-2 show varied effectiveness in TP53-mutated cancers. COTI-2 demonstrated synergy with cisplatin in ovarian cancer, suggesting distinct mechanisms of action for targeted therapies.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- TP53 is the most frequently mutated gene in human cancers, with mutations often affecting DNA binding.
- APR-246 and COTI-2 are investigational small molecules targeting P53-mutated cancers.
- APR-246 binds P53 cysteine residues, altering its conformation; COTI-2's activity in P53 mutant tumors was predicted computationally.
Purpose of the Study:
- To compare the activity of APR-246 and COTI-2 in human tumor explants.
- To investigate potential synergistic effects and correlations with other chemotherapeutics.
- To explore disease-specific activity patterns of these novel agents.
Main Methods:
- Ex vivo analysis of programmed cell death using delayed membrane integrity loss and ATP content assays.
- Determination of lethal concentrations 50 (LC50s) and comparison via Z-Score.
- Synergy assessment using the Chou and Talalay method and correlation analysis by Pearson moment.
Main Results:
- Both APR-246 and COTI-2 showed activity favoring hematologic neoplasms, with variable solid tumor responses.
- No significant correlation was found between APR-246 and COTI-2 activity (R = 0.1028).
- COTI-2 activity correlated with nitrogen mustard, cisplatin, gemcitabine, doxorubicin, and selumetinib; a trend was observed for APR-246 with doxorubicin. Synergy between COTI-2 and cisplatin was observed in ovarian cancer (25%).
Conclusions:
- The distinct activity profiles of COTI-2 and APR-246 suggest different mechanisms of action.
- Lack of correlation supports separate modes of action, potentially enabling targeted therapeutic strategies.
- Observed synergy with cisplatin aligns with TP53's role in DNA damage response, indicating potential for combination therapies.
