Identification of Akt-selective cytotoxic compounds that enhance cytotoxic responses to rapamycin

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Akt and Bcl-xL are key regulators of cell survival pathways implicated in cancer.
• Targeting Akt-dependent survival offers a potential therapeutic strategy.
• Developing selective compounds is crucial to minimize off-target effects.

Purpose of the Study:

• To identify compounds that selectively induce apoptosis in Akt-expressing cells.
• To develop a screening method that accurately reflects cell viability based on survival pathways.
• To find compounds that enhance the efficacy of existing chemotherapeutics.

Main Methods:

• High-throughput screening (HTS) was employed to identify bioactive compounds.
• Alamar Blue assay was initially used but found to underrepresent Bcl-xL-dependent cell viability.
• Plasma membrane integrity assay was developed as a more accurate screening strategy.
• Compounds were tested for their ability to target Akt-dependent survival and enhance rapamycin cytotoxicity.

Main Results:

• The plasma membrane integrity assay successfully identified compounds selective for Akt-expressing cells.
• Two compounds were identified that counteract Akt-dependent cell survival without affecting Bcl-xL-dependent survival.
• These compounds demonstrated synergistic effects when combined with rapamycin, enhancing its cytotoxic potential.

Conclusions:

• A novel, reliable screening method for identifying selective apoptosis-inducing compounds was developed.
• Two promising compounds were discovered that selectively target Akt-dependent survival pathways.
• These findings pave the way for developing more targeted and effective cancer therapies.