Hedgehog Signaling Regulates Hypoxia-Associated Metabolic Adaptation in Myeloid Leukemia In Vitro Cell Models

Area of Science:

• Oncology
• Molecular Biology
• Cancer Metabolism

Background:

• Hedgehog (Hh) signaling is crucial for cell survival and responses to microenvironmental cues in various cancers.
• Its specific role in metabolic adaptation within the hypoxic bone marrow microenvironment of myeloid malignancies is not well understood.

Purpose of the Study:

• To investigate the role of Hedgehog (Hh) signaling, specifically Smoothened (Smo) activity, in metabolic adaptation to hypoxia in myeloid malignancy cell models.
• To elucidate the functional link between Smo activity, cellular metabolism, and the AMPK-mTOR signaling axis.

Main Methods:

• Cultured myeloid malignancy cell lines (K562, KU812, U937) under normoxic and hypoxic conditions.
• Treated cells with Smo antagonist (Cyclopamine) or agonist (SAG).
• Assessed cell proliferation, apoptosis, autophagy, glycolysis-associated proteins, and metabolic parameters using viability assays, Western blotting, immunofluorescence, and biochemical assays; utilized CRISPR/Cas9 for Smo knockout validation.

Main Results:

• Smo inhibition decreased cell proliferation and increased apoptosis markers (PARP cleavage) while decreasing BNIP3 expression under both oxygen conditions.
• Smo inhibition downregulated key glycolytic proteins including GLUT1, HK2, LDH, MCT1, CAIX, and CAXII.
• Metabolic analyses showed reduced glucose consumption, lactate production, and ATP levels following Smo inhibition, linked to AMPK-mTOR pathway modulation.

Conclusions:

• Hedgehog signaling plays a significant role in hypoxia-driven metabolic adaptation in myeloid malignancy cell models.
• Smo activity is functionally linked to glycolytic remodeling and influences the AMPK-mTOR signaling pathway, offering potential therapeutic targets.