The hidden switches underlying RORα-mediated circuits that critically regulate uncontrolled cell proliferation.

Area of Science:

• Oncology
• Molecular Biology
• Systems Biology

Background:

• Prostaglandin E2 (PGE2) plays a complex role in colorectal cancer development, exhibiting both tumor-promoting and tumor-suppressive functions.
• The precise molecular mechanisms underlying PGE2's contrasting effects in tumorigenesis remain incompletely understood.

Purpose of the Study:

• To elucidate the signaling pathways responsible for PGE2's dual roles in colorectal cancer.
• To identify key molecular regulators that control Wnt signaling in response to PGE2 stimulation.

Main Methods:

• Literature review and meta-analysis of previous experiments.
• Biochemical experimentation and mathematical simulations.
• Investigation of signal transduction pathways involving Prostaglandin E2 (PGE2) and retinoic acid receptor-related orphan receptor (ROR)α.

Main Results:

• A novel pathway was identified where PGE2/PKCα-dependent phosphorylation of RORα inhibits Wnt target gene expression in colon cancer cells.
• RORα mediates a biphasic response of Wnt target genes to PGE2 via an incoherent feedforward loop, explaining PGE2's contrasting roles.
• RORα forms feedback loops regulating Wnt signaling hysteresis, converting proliferative to anti-proliferative states.

Conclusions:

• RORα acts as a central regulator, orchestrating complex signaling switches that control cancer cell proliferation.
• RORα represents a promising therapeutic target for colorectal cancer intervention due to its critical role in regulating cancer cell growth.