An HDAC8-selective fluorescent probe for imaging in living tumor cell lines and tissue slices

Area of Science:

• Biochemistry and Molecular Biology
• Chemical Biology
• Cancer Research

Background:

• Histone deacetylase 8 (HDAC8) is highly expressed in neuroblastoma and breast cancer cells, making it a significant therapeutic target.
• The development of selective fluorescent probes for HDAC8 is crucial for cancer research and diagnostics.
• Existing therapeutic agents targeting HDAC8 require complementary imaging tools for effective application.

Purpose of the Study:

• To design and synthesize novel fluorescent probes with high selectivity for HDAC8.
• To evaluate the imaging capabilities of these probes in cancer cells and tissues.
• To explore their potential applications in HDAC8-targeted drug screening and pathological diagnosis.

Main Methods:

• Conjugation of 1,8-naphthalimide with PCI-34051, a selective HDAC8 inhibitor, to create NP-C6-PCI and AM-C6-PCI.
• Affinity determination using dissociation constants (K_D) to assess selectivity for HDAC8.
• Fluorescence spectroscopy to analyze emission intensity and Stokes shift.
• Cellular and tissue imaging experiments using SH-SY5Y and MDA-MB-231 tumor models.

Main Results:

• NP-C6-PCI and AM-C6-PCI exhibited significantly higher selectivity for HDAC8 compared to PCI-34051, with K_D values in the 10^-6 M range.
• Both probes displayed strong fluorescence intensity at 450 nm excitation and a large Stokes shift of 100 nm.
• NP-C6-PCI successfully targeted and imaged HDAC8 expression in SH-SY5Y and MDA-MB-231 tumor cells.
• NP-C6-PCI effectively visualized HDAC8 levels in SH-SY5Y tumor tissue slices.

Conclusions:

• Novel HDAC8-selective fluorescent probes, NP-C6-PCI and AM-C6-PCI, have been successfully developed.
• These probes offer enhanced selectivity and fluorescence properties for HDAC8 detection.
• NP-C6-PCI demonstrates significant potential for applications in HDAC8-targeted drug screening and pathological diagnosis of cancers.