Identification and Validation of an Aspergillus nidulans Secondary Metabolite Derivative as an Inhibitor of the
Lan Lan1, Jiajun Liu1, Minli Xing2
1Departments of Molecular Biosciences, the University of Kansas, Lawrence, KS 66045, USA.
Abstract:
RNA-binding protein Musashi-1 (MSI1) is a key regulator of several stem cell populations. MSI1 is involved in tumor proliferation and maintenance, and it regulates target mRNAs at the translational level. The known mRNA targets of MSI1 include Numb, APC, and P21, key regulators of Notch/Wnt signaling and cell cycle progression, respectively. In this study, we aim to identify small molecule inhibitors of MSI1-mRNA interactions, which could block the growth of cancer cells with high levels of MSI1. Using a fluorescence polarization (FP) assay, we screened small molecules from several chemical libraries for those that disrupt the binding of MSI1 to its consensus RNA. One cluster of hit compounds is the derivatives of secondary metabolites from Aspergillus nidulans. One of the top hits, Aza-9, from this cluster was further validated by surface plasmon resonance and nuclear magnetic resonance spectroscopy, which demonstrated that Aza-9 binds directly to MSI1, and the binding is at the RNA binding pocket. We also show that Aza-9 binds to Musashi-2 (MSI2) as well. To test whether Aza-9 has anti-cancer potential, we used liposomes to facilitate Aza-9 cellular uptake. Aza-9-liposome inhibits proliferation, induces apoptosis and autophagy, and down-regulates Notch and Wnt signaling in colon cancer cell lines. In conclusion, we identified a series of potential lead compounds for inhibiting MSI1/2 function, while establishing a framework for identifying small molecule inhibitors of RNA binding proteins using FP-based screening methodology.
Insights
Researchers identified Aza-9, a small molecule inhibitor targeting RNA-binding proteins Musashi-1 (MSI1) and Musashi-2 (MSI2). This compound shows potential for blocking cancer cell growth by disrupting MSI1-mRNA interactions and inhibiting key cancer signaling pathways.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Musashi-1 (MSI1) is an RNA-binding protein crucial for stem cell regulation and implicated in cancer proliferation.
- MSI1 controls target mRNAs, including Numb, APC, and P21, which are vital for Notch/Wnt signaling and cell cycle progression.
- Developing inhibitors of MSI1-mRNA interactions is a promising strategy to combat MSI1-driven cancers.
Purpose of the Study:
- To identify small molecules that inhibit MSI1-mRNA interactions.
- To evaluate the anti-cancer potential of identified inhibitors in colon cancer cell lines.
- To establish a screening methodology for RNA-binding protein inhibitors.
Main Methods:
- High-throughput screening using a fluorescence polarization (FP) assay to detect disruption of MSI1-RNA binding.
- Validation of hit compounds using surface plasmon resonance (SPR) and nuclear magnetic resonance (NMR) spectroscopy.
- Assessment of Aza-9's anti-cancer effects using liposome-mediated cellular delivery in colon cancer cell lines.
Main Results:
- Aza-9, a derivative of Aspergillus nidulans secondary metabolites, was identified as a potent inhibitor that binds directly to MSI1's RNA binding pocket.
- Aza-9 also demonstrated binding to Musashi-2 (MSI2).
- Aza-9-liposome effectively inhibited colon cancer cell proliferation, induced apoptosis and autophagy, and downregulated Notch and Wnt signaling.
Conclusions:
- Aza-9 and related compounds represent potential lead molecules for MSI1/2-targeted cancer therapies.
- The study validates FP-based screening as an effective method for discovering small molecule inhibitors of RNA-binding proteins.
- Targeting MSI1/2 interactions offers a novel therapeutic strategy for cancers with high MSI1 expression.
