N4-acetylcytidine modifies primary microRNAs for processing in cancer cells

Area of Science:

• Molecular Biology
• Epigenetics
• Cancer Research

Background:

• N4 acetylcytidine (ac4C) modification is crucial for genetic information expression, primarily on tRNA, rRNA, and mRNA.
• The role of ac4C modification in microRNAs (miRNAs) and its physiological/pathological functions remain largely unknown.

Purpose of the Study:

• To investigate whether microRNAs undergo ac4C modification.
• To elucidate the role of NAT10/THUMPD1 in pri-miRNA ac4C modification.
• To explore the impact of pri-miRNA ac4C on miRNA biogenesis and cancer progression.

Main Methods:

• Identification of NAT10/THUMPD1 as enzymes responsible for ac4C modification in pri-miRNAs.
• Experimental manipulation (knockdown) of NAT10 to assess its effects on pri-miRNA and mature miRNA expression levels.
• Molecular mechanism studies to analyze the interaction between pri-miRNA, DGCR8, and the processing of pre-miRNA.
• Analysis of NAT10 expression in clinical cancer samples and its correlation with patient prognosis.

Main Results:

• NAT10/THUMPD1 was identified as the enzyme that acetylates primary microRNAs (pri-miRNAs) with ac4C.
• NAT10 knockdown led to decreased mature miRNA and increased pri-miRNA levels.
• ac4C modification on pri-miRNA enhances its processing into precursor miRNA (pre-miRNA) by improving pri-miRNA-DGCR8 interaction, boosting mature miRNA biogenesis.
• NAT10 knockdown reduced the oncogenic characteristics of lung cancer cells via miRNA production regulation.
• NAT10 is highly expressed in various cancers and associated with poor prognosis.

Conclusions:

• NAT10 plays a critical role in cancer initiation and progression by modulating ac4C modification of pri-miRNAs, thereby affecting miRNA production.
• Targeting NAT10 offers a potential therapeutic strategy for cancers by influencing miRNA biogenesis.