3'-Phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1) knockdown sensitizes non-small cell lung cancer cells to...

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Standard platinum-based chemotherapy for advanced non-small cell lung cancer (NSCLC) has limited efficacy, with response rates around 30-33%.
• There is a critical need for novel therapeutic targets to improve treatment outcomes in NSCLC patients lacking known driver mutations.

Purpose of the Study:

• To identify novel targets that can sensitize NSCLC cells to platinum-based chemotherapy.
• To investigate the role of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthase 1 (PAPSS1) as a potential therapeutic target in NSCLC.

Main Methods:

• An siRNA screen was employed to identify genes involved in platinum resistance.
• PAPSS1 knockdown was performed in NSCLC cells, followed by treatment with cisplatin (IC10 dose).
• Assays were conducted to measure clonogenicity, DNA damage, cell cycle progression, apoptosis, and sensitivity to various DNA-damaging agents.

Main Results:

• PAPSS1 knockdown in NSCLC cells, combined with low-dose cisplatin, reduced clonogenicity by 98.7%, increased DNA damage, and induced G1/S cell cycle arrest and apoptosis.
• PAPSS1 silencing sensitized NSCLC cells to DNA crosslinking agents, radiation, and topoisomerase I inhibitors, but not topoisomerase II inhibitors.
• Chemo-sensitization was specific to cancer cells, as normal epithelial cells did not exhibit increased sensitivity.

Conclusions:

• PAPSS1 is a novel platinum-sensitizing target in NSCLC, and its inhibition can significantly enhance the efficacy of multiple anticancer agents.
• Targeting PAPSS1 offers a promising strategy to improve the therapeutic activity of existing treatments for advanced NSCLC.
• The sensitization mechanism likely involves sulfation reactions critical for DNA damage response or cellular stress adaptation, rather than general sulfate bioavailability.