LncRNA TMEM99 Complexes with IGF2BP2 to Inhibit Autophagy in Lung Adenocarcinoma

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Lung adenocarcinoma (LUAD) has a poor prognosis, with long noncoding RNAs (lncRNAs) implicated in its progression.
• The specific role of lncRNA TMEM99 in LUAD remains largely unknown, particularly its involvement in cellular processes like autophagy.

Purpose of the Study:

• To investigate the biological function and molecular mechanisms of lncRNA TMEM99 in lung adenocarcinoma.
• To determine TMEM99's role in regulating autophagy and its impact on LUAD progression.

Main Methods:

• RNA sequencing and quantitative reverse transcription PCR (qRT-PCR) to assess TMEM99 expression.
• In vivo and in vitro assays to evaluate TMEM99's effects on cell proliferation, migration, invasion, and autophagy.
• Mechanistic studies involving protein-RNA interactions and m6A-dependent regulation.

Main Results:

• TMEM99 was found to be upregulated in LUAD tissues and cell lines, correlating with poorer patient outcomes.
• TMEM99 overexpression promoted LUAD cell proliferation, migration, and invasion while inhibiting autophagy.
• TMEM99 stabilizes FUBP3 protein by binding to its KH1 and KH4 domains, forming a complex that enhances p21 mRNA stability and translation via IGF2BP2 in an m6A-dependent manner.

Conclusions:

• lncRNA TMEM99 plays a significant role in promoting LUAD progression by inhibiting autophagy.
• A novel cytoplasmic regulatory mechanism involving TMEM99, FUBP3, p21 mRNA, and IGF2BP2 (m6A-dependent) contributes to LUAD pathogenesis.