A novel small molecule hydroxamate preferentially inhibits HDAC6 activity and tumour growth

Area of Science:

• Oncology
• Pharmacology
• Molecular Biology

Background:

• Solid tumors represent a significant challenge in cancer treatment.
• Histone deacetylase subtype 6 (HDAC6) is a potential therapeutic target.
• Developing novel inhibitors for solid tumors is crucial.

Purpose of the Study:

• To investigate the therapeutic potential of a novel HDAC6 inhibitor, C1A, for solid tumors.
• To evaluate C1A's efficacy in inhibiting cancer cell growth and tumor progression.
• To assess the utility of [(18)F]fluorothymidine positron emission tomography ([(18)F]FLT-PET) for monitoring treatment response.

Main Methods:

• Biochemical assays to assess C1A's effect on HDAC6 activity.
• In vitro studies on human tumor cell lines to evaluate cell growth inhibition and apoptosis.
• In vivo studies using colon tumor models to determine C1A's efficacy.
• [(18)F]FLT-PET imaging to monitor tumor proliferation and treatment response.

Main Results:

• C1A demonstrated sustained acetylation of HDAC6 substrates (α-tubulin, HSP90) compared to SAHA.
• C1A inhibited proliferation and induced apoptosis in various human tumor cell lines at low micromolar concentrations.
• Systemic C1A administration reduced colon tumor growth by 78% in vivo.
• C1A treatment led to a 1.7-fold reduction in tumor [(18)F]FLT uptake at 48 hours, indicating potential for imaging therapy response.

Conclusions:

• C1A selectively inhibits HDAC6, leading to downstream target modulation and significant cancer cell growth inhibition.
• The compound exhibits favorable pharmacokinetics and in vivo efficacy.
• C1A is a promising candidate for further preclinical and clinical development in solid tumor treatment.