RNA Binding of GAPDH Controls Transcript Stability and Protein Translation in Acute Myeloid Leukemia

Area of Science:

• Molecular Biology
• Cancer Research
• Hematology

Background:

• Dysregulation of RNA binding proteins (RBPs) is a hallmark of cancer, particularly in acute myeloid leukemia (AML), where they regulate tumor proliferation.
• While canonical RBPs are well-studied, the roles of non-canonical RBPs (ncRBPs) in AML remain largely unknown.
• Targeting AML broadly is complex, necessitating the identification of novel therapeutic targets like ncRBPs.

Purpose of the Study:

• To identify novel non-canonical RNA binding protein candidates crucial for acute myeloid leukemia survival.
• To investigate the RNA binding functions and targets of identified ncRBPs in AML.
• To elucidate the mechanisms by which ncRBPs contribute to AML cell proliferation and survival.

Main Methods:

• CRISPR/Cas-based screening was employed to identify potential ncRBPs in AML.
• Cross-linking and immunoprecipitation (CLIP) was used to define the global RNA targetome of identified ncRBPs.
• Knockdown experiments were performed to assess the functional impact of ncRBPs on AML cell pathways.

Main Results:

• Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic enzyme, was identified as a pro-proliferative factor in AML cells.
• CLIP analysis revealed novel RNA targets of GAPDH, primarily in 5'UTRs, including GAPDH, RPL13a, and PKM transcripts.
• GAPDH knockdown affected genetic pathways involved in ribosome biogenesis, translation initiation, and regulation.
• GAPDH binding to target transcripts, including its own mRNA, demonstrated a stabilizing effect.

Conclusions:

• GAPDH functions as a non-canonical RNA binding protein that promotes proliferation in acute myeloid leukemia.
• GAPDH regulates key cellular processes in AML through binding to specific RNA targets, influencing translation and ribosome biogenesis.
• These findings offer new insights into the multifaceted roles of GAPDH in AML, highlighting its potential as a therapeutic target.