Structure-Based Design of Transport-Specific Multitargeted One-Carbon Metabolism Inhibitors in Cytosol and...

Area of Science:

• Oncology
• Medicinal Chemistry
• Biochemistry

Background:

• Multitargeted agents offer improved cancer treatment by enhancing tumor selectivity and reducing drug resistance and toxicity.
• Previous antifolate compound 1 demonstrated activity against pancreatic tumors but lacked sufficient selectivity.

Purpose of the Study:

• To design and synthesize novel multitargeted antifolate analogues with enhanced tumor selectivity and potency.
• To identify targeted metabolic pathways and mechanisms of selective tumor transport.

Main Methods:

• Structure-based drug design utilizing X-ray crystal structures of key enzymes (SHMT2, GARFTase, ATIC) and receptors (FR α and β).
• Synthesis of 11 novel 6-substituted pyrrolo[3,2-d]pyrimidine analogues.
• Metabolite rescue experiments to identify targeted pathways.
• In vitro enzymatic inhibition assays and cellular transport studies.

Main Results:

• Identified 11 novel antifolate analogues with multitargeted inhibition profiles.
• Achieved enhanced inhibition of SHMT2 (28-fold), SHMT1 (21-fold), and GARFTase (11-fold) compared to compound 1.
• Demonstrated tumor-selective transport mediated by folate receptors (FRs).
• Identified mitochondrial C1 metabolism and de novo purine biosynthesis as key targeted pathways.

Conclusions:

• The novel multitargeted antifolates exhibit significant improvements in tumor selectivity and potency over existing antifolates.
• These agents represent a promising new structural class for targeted cancer therapy.
• The design strategy effectively combined multitargeted inhibition with selective tumor-specific transport.