AKT Inhibition Promotes Nonautonomous Cancer Cell Survival

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Small molecule inhibitors targeting AKT (v-akt murine thymoma viral oncogene homolog) signaling are under investigation for cancer therapy.
• Despite therapeutic potential, AKT inhibitors have yielded disappointing clinical outcomes, with underlying mechanisms poorly understood.

Purpose of the Study:

• To investigate the molecular consequences of subtherapeutic AKT inhibition in cancer cells.
• To model the "AKT(low)" cancer cell state using integrated multi-omics profiling.
• To understand how partial AKT inhibition influences cancer cell survival and intercellular communication.

Main Methods:

• Treatment of cancer cells with subtherapeutic doses of the AKT inhibitor Akti-1/2.
• Application of combined RNA, protein, and metabolite profiling (multi-omics).
• Analysis of extracellular microvesicle production and functional assays under various stress conditions (in vitro and in vivo xenografts).

Main Results:

• AKT inhibition led to suppression of thousands of mRNA transcripts and proteins related to cell cycle and translation.
• Post-transcriptional upregulation of proteins and metabolites involved in the endo-vesiculo-membrane system and inflammatory secretion.
• Elaboration of extracellular microvesicles that conferred resistance to stress conditions (serum deprivation, hypoxia, chemotherapy) and improved xenograft survival.

Conclusions:

• Partial AKT inhibition induces a complex cellular state characterized by suppressed proliferation and enhanced stress resistance via microvesicle release.
• Extracellular microvesicles mediate non-cell autonomous communication, promoting the survival of neighboring cancer cells.
• These findings suggest a novel therapeutic resistance mechanism and highlight the importance of intercellular communication in cancer progression.