Positive Selection Screen for Natural Product β-Catenin Inactivators.

Area of Science:

• Natural product discovery
• Cell-based assays
• Oncogene research

Background:

• Cell-based phenotypic screening of natural products offers insights but faces challenges with mixture complexity and toxicity.
• Traditional screening methods often struggle with deconvoluting complex natural product mixtures.
• Toxins in natural products can interfere with cellular assays, leading to unreliable results.

Purpose of the Study:

• To mitigate challenges in natural product screening by using prefractionated mixtures in cell-based "up" assays.
• To identify natural products that can modulate oncogenic pathways.
• To explore novel therapeutic strategies targeting cancer.

Main Methods:

• High-throughput screening of 326,304 natural product samples (extracts and fractions).
• Utilized mammalian cells engineered to express an oncogenic β-catenin (β-cat) fusion protein.
• Assayed for degradation or compartmentalization of the β-cat fusion protein.

Main Results:

• Identified multiple natural product fractions that degraded the oncogenic β-cat fusion protein.
• Discovered fractions that relocated the β-cat fusion protein to inactive compartments.
• Isolated a compound that activates novel protein kinase Cs (PKCs), relocating β-cat to juxtamembrane vacuolar structures.

Conclusions:

• Prefractionation and cell-based "up" assays can overcome limitations in natural product screening.
• Natural products can provide novel mechanisms for targeting oncogenic proteins like β-catenin.
• This approach highlights the potential of natural products in drug discovery and cancer therapy.