Defining targets of modulation of human tumor cell response to cisplatin

Area of Science:

• Cancer research
• Molecular biology
• Drug resistance mechanisms

Background:

• Cisplatin is a widely used chemotherapy drug.
• Understanding cisplatin resistance is crucial for improving cancer treatment.
• Yeast studies revealed cisplatin activates stress response pathways.

Purpose of the Study:

• Investigate cisplatin's modulation of drug response genes in human tumor cells.
• Determine if these responses differ in cisplatin-resistant cell lines.
• Explore potential therapeutic strategies targeting stress response pathways.

Main Methods:

• Utilized human tumor cell lines (sensitive and cisplatin-resistant sublines).
• Analyzed gene expression related to stress response pathways (glutathione-S-transferase, proteasome, checkpoint control, recombinational repair).
• Pharmacologically targeted specific pathways (glutathione, proteasome, heat shock protein 90) to assess chemosensitization.

Main Results:

• Cisplatin upregulated stress response factors in both sensitive and resistant human tumor cells.
• Targeting glutathione or proteasome sensitized both sensitive and resistant cells to cisplatin.
• In specific resistant cells (IGROV-1/Pt1), targeting heat shock protein 90 (HSP90) sensitized cells, indicating a protective role of stress response.
• HSP70 and HSP90 were upregulated by cisplatin in IGROV-1/Pt1 cells.

Conclusions:

• Stress response pathways are activated by cisplatin in human tumor cells, partly mirroring yeast responses.
• Pharmacological targeting of glutathione and proteasome can overcome cisplatin resistance.
• Interfering with heat shock protein response, particularly HSP90, shows potential for increasing cisplatin efficacy in resistant cancers.