Context-Specific Metabolic Alterations in HPRT1 Knockout Cells Within a 3D Culture System

Area of Science:

• Metabolic reprogramming in cancer
• 3D cell culture models
• Cancer metabolism

Background:

• Cancer cells alter metabolism for proliferation, but in vitro findings differ from in vivo due to varying environments.
• 3D culture models mimic in vivo conditions, improving translational research accuracy.
• Investigating hypoxanthine-guanine phosphoribosyltransferase 1 (HPRT1) in small cell lung cancer (SCLC) using 2D and 3D models.

Purpose of the Study:

• To investigate the impact of HPRT1 on SCLC proliferation and metabolism.
• To identify context-specific metabolic regulations missed by 2D cultures.
• To compare HPRT1's role in SCLC across 2D, 3D, and in vivo models.

Main Methods:

• Evaluated cell proliferation in HPRT1-knockout (KO) SCLC cells across 2D, 3D, and xenograft models.
• Performed metabolomic profiling using CE-TOFMS and pathway analysis.
• Assessed beta-alanine (β-Ala) metabolism gene expression (CARNS1) via RNA-seq/RT-PCR and analyzed public lung cancer datasets.

Main Results:

• HPRT1 KO significantly reduced proliferation in 3D/in vivo, with minimal effect in 2D.
• Metabolomic analysis revealed extensive alterations in amino acid and purine metabolism.
• HPRT1 KO increased carnosine and CARNS1 expression in 3D cultures; high CARNS1 correlated with better prognosis and lower HPRT1 in lung cancer patients.

Conclusions:

• 3D culture systems reveal context-specific metabolic regulation, like HPRT1's suppression of carnosine production.
• Metabolic phenotypes in 2D cultures may not reflect in vivo complexity.
• 3D models uncover overlooked regulatory pathways, including HPRT1's context-dependent regulation of carnosine metabolism.