The Transcription Axes ERK-Elk1, JNK-cJun, and JAK-STAT Promote Autophagy Activation and Proteasome Inhibitor...

Area of Science:

• Oncology
• Cancer Biology
• Pharmacology

Background:

• Proteasome inhibitors are effective against hematological cancers but face resistance in solid tumors.
• Mechanisms of resistance to proteasome inhibitors in solid tumors are complex and not fully understood.
• Prostate cancer, particularly with high metastatic potential, serves as a relevant model for studying resistance.

Purpose of the Study:

• To create and characterize a Bortezomib-resistant prostate cancer cell line (PC-3).
• To investigate the biochemical and signaling pathway alterations associated with acquired resistance.
• To identify potential therapeutic targets for overcoming proteasome inhibitor resistance in solid tumors.

Main Methods:

• Development of a Bortezomib-resistant prostate cancer cell line (PC-3).
• Analysis of apoptosis evasion, autophagy induction, and epithelial-to-mesenchymal transition markers.
• Broad-spectrum signaling pathway analysis, including transcription factor activation (Nf-κB, STAT3, cJun, Elk1).
• Measurement of intracellular reactive oxygen species (ROS) levels.

Main Results:

• Resistant cells exhibited apoptosis evasion, increased autophagy (compensating for proteasome inhibition), and enhanced aggressiveness.
• Upregulation and activation of transcription factors Nf-κB, STAT3, cJun, and Elk1 were observed in resistant cells.
• Resistant cells showed downregulated intracellular ROS, potentially due to metabolic shifts and increased autophagy.

Conclusions:

• Acquired resistance to proteasome inhibitors involves complex adaptations including apoptosis evasion and autophagy.
• Specific transcription factors (Nf-κB, STAT3, cJun, Elk1) are key players in mediating resistance.
• Targeting resistance-specific pathways presents a promising strategy to re-sensitize solid tumors to proteasome inhibitors.