STAT3 and MCL-1 associate to cause a mesenchymal epithelial transition

Area of Science:

• Reproductive biology
• Molecular and Cell Biology
• Cancer Biology

Background:

• Embryo implantation involves complex signaling pathways on the embryo-endometrium axis.
• Cellular plasticity, including epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET), is crucial for development and homeostasis.
• STAT3 and MCL-1 are key proteins involved in cellular processes relevant to implantation and cancer.

Purpose of the Study:

• To investigate the interaction between STAT3 and MCL-1 during embryo implantation.
• To determine the regulatory mechanisms of this interaction by hormones.
• To explore the functional consequences of STAT3-MCL-1 association on cellular plasticity and apoptosis.

Main Methods:

• MALDI TOF analysis
• Far-western analysis
• Colocalization studies
• Co-transfection studies in MCF7 cells

Main Results:

• STAT3 and MCL-1 form an interacting complex during embryo implantation.
• Estrogen and progesterone significantly regulate the interaction between STAT3 and MCL-1 in vitro.
• The association of STAT3 with MCL-1 in MCF7 cells increases apoptosis and reduces cellular invasion, disrupting EMT.
• STAT3 binding modulates MCL-1's anti-apoptotic activity, leading to pro-apoptotic effects.

Conclusions:

• The interaction between STAT3 and MCL-1 is a novel finding in embryo implantation.
• Hormonal regulation of STAT3-MCL-1 interaction highlights its role in reproductive processes.
• Understanding STAT3-MCL-1's impact on MET could offer insights into infertility and metastatic tumors.