Decreased Expression by a Chemically Modified siRNA to PTBP1 Seriously Affects Warburg Effect in Colorectal Cancer...

Area of Science:

• Molecular Biology
• Cancer Metabolism
• RNA Therapeutics

Background:

• Cancer cells utilize aerobic glycolysis (Warburg effect) for growth.
• PTBP1 maintains PKM2 dominance, sustaining the Warburg phenotype.
• PTBP1 suppression shifts cancer metabolism, enhancing oxidative phosphorylation and apoptosis.

Purpose of the Study:

• To investigate the therapeutic potential of targeting PTBP1 using chemically modified siRNAs.
• To evaluate the efficacy of siRNAs targeting different regions of PTBP1 mRNA in colorectal cancer cells.
• To assess the metabolic consequences and cytotoxicity induced by PTBP1 suppression.

Main Methods:

• Synthesis and evaluation of thirteen chemically modified siR-PTBP1 derivatives.
• Assessment of cytotoxicity, protein expression, oxidative stress, and metabolic alterations in colorectal cancer cell lines.
• Evaluation of siRNA stability against nuclease degradation and quantification via TaqMan RT-qPCR.

Main Results:

• 3'-UTR targeting siRNAs were more effective in suppressing PTBP1 and increasing the PKM1/PKM2 ratio than coding-region targeting siRNAs.
• Derivative 2-6 demonstrated potent cytotoxicity, inducing oxidative stress and apoptosis, with enhanced resistance to nucleases.
• Metabolomic analysis revealed altered glycolytic flux, elevated TCA cycle metabolites, and activated redox responses without energy collapse.

Conclusions:

• Chemically modified siR-PTBP1, particularly derivative 2-6, effectively targets PTBP1, inducing a metabolically vulnerable state and apoptosis in cancer cells.
• PTBP1 is a key regulator of the Warburg effect, making it a viable target for cancer therapy.
• siRNA-based metabolic targeting represents a promising therapeutic strategy for colorectal cancer.