GABARAPL1 Inhibits EMT Signaling through SMAD-Tageted Negative Feedback

Area of Science:

• Molecular Biology
• Cell Biology
• Cancer Research

Background:

• Selective autophagy, mediated by ATG8 proteins, is implicated in Epithelial-mesenchymal transition (EMT).
• The precise molecular mechanisms of selective autophagy in EMT remain largely uncharacterized.
• Understanding these mechanisms is crucial for cancer etiology and progression.

Purpose of the Study:

• To investigate the role of ATG8 proteins, specifically GABARAPL1, in regulating EMT.
• To elucidate the molecular interplay between GABARAPL1, SMAD signaling, and EMT in lung adenocarcinoma.

Main Methods:

• Transcriptome analysis and immunohistochemistry on lung adenocarcinoma tumors.
• EMT induction in A549 cells using TGF-β/TNF-α.
• CRISPR/Cas9-mediated GABARAPL1 depletion in A549 and ACHN cell lines.

Main Results:

• ATG8 gene expression correlates with EMT markers; GABARAPL1 protein is upregulated in EMT+ tumors.
• EMT induction increases GABARAPL1 expression via SMAD transcription factors.
• GABARAPL1 depletion promotes EMT by impairing SMAD protein degradation.

Conclusions:

• GABARAPL1 plays a regulatory role in EMT, potentially through a feedback loop involving SMAD signaling.
• Increased GABARAPL1 levels during EMT lead to SMAD degradation, suggesting an inhibitory effect on EMT.
• GABARAPL1 represents a potential therapeutic target for modulating EMT in cancer.