Anticancer effect of adenosine on gastric cancer via diverse signaling pathways

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Oncology

Background:

• Extracellular adenosine induces apoptosis in various cancer cells through intrinsic and extrinsic pathways.
• Adenosine's role in gastric cancer cell apoptosis involves cellular uptake and receptor-mediated signaling.
• Mechanisms differ based on gastric cancer cell subtypes, necessitating a nuanced understanding.

Purpose of the Study:

• To elucidate the distinct mechanisms by which extracellular adenosine induces apoptosis in different gastric cancer cell lines.
• To investigate the roles of adenosine transporters, adenosine kinase, AMP-activated protein kinase (AMPK), and adenosine receptors in apoptosis.
• To identify downstream molecular targets for developing targeted gastric cancer chemotherapy.

Main Methods:

• Analysis of adenosine uptake and intracellular conversion to AMP.
• Assessment of AMP-activated protein kinase (AMPK) activation.
• Investigation of adenosine receptor (A3) signaling pathways, including G protein coupling and downstream effectors like phospholipase Cγ and protein kinase C.
• Comparative analysis of apoptosis induction in GT3-TKB, MKN28, and MKN45 gastric cancer cells.

Main Results:

• Extracellular adenosine induces caspase-independent apoptosis in GT3-TKB cells via AMPK activation.
• Extracellular adenosine induces caspase-dependent apoptosis in MKN28 and MKN45 cells through both AMPK-independent AMP signaling and A3 adenosine receptor activation.
• A3 receptor signaling involves Gi/Gq proteins, phospholipase Cγ, and protein kinase C activation.

Conclusions:

• The mechanisms of adenosine-induced apoptosis in gastric cancer are cell-type specific.
• Distinct intracellular pathways (AMPK-dependent vs. independent) and receptor-mediated signaling contribute to apoptosis.
• Understanding these varied molecular mechanisms is crucial for developing personalized gastric cancer chemotherapy strategies.