Selective HDAC6 Inhibitors for Lower-Toxicity Cancer Sensitization
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Solution Overview
Problem
Current HDAC inhibitors lack selectivity for HDAC6, limiting their effectiveness in treating conditions like cancer and neurological diseases, and there is a need for enhancing the sensitivity of cancer cells to radiotherapy and chemotherapy.
Innovation Solution
Development of selective HDAC6 inhibitors, such as phenylhydroxamic acids, which are administered in combination with anti-PD1 immunotherapy to modulate immune responses and enhance the cytotoxic effects of radiotherapy and chemotherapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If panobinostat or other HDAC inhibitors are used to treat cancer, then anti-cancer activity is achieved, but selective inhibition of HDAC6 is not obtained leading to increased side effects
Solution Approach 1:
The patent applies local quality by designing inhibitors with specific molecular structures (e.g., hydroxamic acid derivatives with particular substituents at R1, R2, R3 positions) that selectively bind to HDAC6's active site while excluding other HDAC isoforms. This structural differentiation enables selective inhibition at the molecular level, targeting only the desired enzyme variant.
Solution Approach 2:
The patent employs parameter changes by systematically varying chemical parameters of the inhibitor molecules (substituent types, positions, and configurations) to modulate selectivity toward HDAC6. By adjusting these chemical parameters, the invention achieves differential binding affinity across HDAC isoforms, enabling selective inhibition.
2Reliability
If non-selective HDAC inhibitors are used, then broad anti-cancer activity is achieved, but toxicity increases due to off-target effects
Solution Approach 1:
The patent applies local quality by incorporating specific structural features (such as particular substituent patterns on the aromatic ring system) that confer selective recognition by HDAC6. This localized structural differentiation ensures that only HDAC6 is inhibited while other isoforms remain unaffected, improving the therapeutic index.
Solution Approach 2:
The patent uses the hydroxamic acid group as an intermediary that mediates selective binding to HDAC6. This functional group acts as a bridge between the inhibitor molecule and the zinc ion in HDAC6's active site, providing both potency and selectivity through specific coordination chemistry.
3Productivity
If existing HDAC inhibitors like vorinostat or panobinostat are administered, then cancer cell growth inhibition is achieved, but selective HDAC6 inhibition is not realized
Solution Approach 1:
The patent applies local quality by introducing specific substituent patterns (such as fluorine atoms at particular positions, or specific alkyl groups) that create a unique molecular fingerprint recognized only by HDAC6. This localized structural optimization maintains anti-cancer efficacy while achieving isoform selectivity.
Solution Approach 2:
The patent employs parameter changes by systematically modifying chemical parameters including substituent electronegativity, steric bulk, and hydrogen bonding capacity to fine-tune selectivity for HDAC6 while preserving anti-proliferative activity against cancer cells.
Data Source
Figure 1A~1F
Figure 2
Figure 3A~3B
AI summary
The present disclosure provides methods, pharmaceutical compositions, and kits comprising histone deacetylase (HD AC) inhibitors of formula I, or a pharmaceutically acceptable salt thereof, wherein R1, R2, L1, L2, m, n, p, X, Y, and Z are as defined in the specification, including methods of increasing the sensitivity of cancer cells to the cytotoxic effects of radiotherapy and/or chemotherapy in a subject.