PI3K-AKT, JAK2-STAT3 pathways and cell-cell contact regulate maspin subcellular localization

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• Maspin (SERPINB5) is a tumor suppressor gene involved in cell growth, death, and adhesion.
• Nuclear localization of maspin is crucial for its tumor suppressor activity.
• EGFR activation promotes maspin nuclear localization in MCF-10A cells.

Purpose of the Study:

• To identify EGFR downstream signaling molecules regulating maspin nuclear localization.
• To investigate the influence of cell-cell contact on maspin nuclear localization.

Main Methods:

• MCF-10A cells were treated with EGFR pathway inhibitors and EGF.
• Maspin subcellular localization was assessed using immunofluorescence.
• Proteomic and interactome analyses identified maspin-binding proteins.
• Cell-cell contact effects were studied using chelating agents and varying cell densities.

Main Results:

• PI3K-Akt and JAK2-STAT3 pathways, not MAPK, mediate EGF-induced maspin nuclear accumulation.
• Maspin is nuclear in sparse cells but cytoplasmic in confluent cells, even with EGF.
• Proteomics suggest maspin's role in post-transcriptional regulation, protein folding, and cell adhesion.

Conclusions:

• Maspin nuclear accumulation is regulated by an interplay between EGFR signaling (PI3K-Akt, JAK2-STAT3) and cell-cell contact.
• Cell-cell adhesion influences maspin's subcellular localization, impacting its function.