Selectively Targeting STAT3 Using a Small Molecule Inhibitor is a Potential Therapeutic Strategy for Pancreatic...

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Pancreatic cancer has a poor prognosis, necessitating novel therapeutic strategies.
• Signal transducer and activator of transcription 3 (STAT3) is a validated target in pancreatic cancer.
• Developing selective small molecule inhibitors for STAT3 remains a significant challenge.

Purpose of the Study:

• To identify and characterize a novel, selective small molecule inhibitor of STAT3.
• To evaluate the therapeutic potential of the identified inhibitor in preclinical models of pancreatic cancer.

Main Methods:

• Structure-based virtual screening of over 1.3 million compounds.
• Direct binding assays, molecular docking, and site-directed mutagenesis for target validation.
• In vitro assays (kinase assays, cell viability) and in vivo studies in four animal models.

Main Results:

• WB436B selectively binds to STAT3 with significantly enhanced in vitro potency compared to existing inhibitors.
• WB436B effectively inhibits STAT3 phosphorylation, downstream gene expression, and viability of STAT3-dependent pancreatic cancer cells.
• In vivo studies demonstrated that WB436B suppresses tumor growth and metastasis, prolonging survival in mice.

Conclusions:

• WB436B is the first-in-class selective STAT3 inhibitor identified.
• WB436B demonstrates significant preclinical efficacy and represents a promising therapeutic candidate for pancreatic cancer treatment.