Akt3 knockdown induces mitochondrial dysfunction in human cancer cells

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• The serine/threonine kinase Akt (also known as Protein Kinase B or PKB) is crucial for cell proliferation and survival.
• The specific roles of Akt isoforms in regulating mitochondrial function remain incompletely understood.

Purpose of the Study:

• To investigate the distinct roles of Akt isoforms in mitochondrial function within human cancer cells.
• To explore the impact of Akt isoform knockdown on mitochondrial mass, structure, and respiration.

Main Methods:

• Stable knockdown of Akt isoforms (Akt1, Akt2, Akt3) in EJ human bladder cancer cells.
• Analysis of mitochondrial mass, mitochondrial transcription factor A (TFAM), and nuclear respiratory factor 1 (NRF1) expression.
• Assessment of mitochondrial structure, doxorubicin-induced senescence, cell proliferation in galactose medium, and mitochondrial oxygen consumption rate.

Main Results:

• Akt1 and Akt3 knockdown led to increased mitochondrial mass, TFAM, and NRF1 levels.
• Akt3 knockdown resulted in mitochondrial structural defects, increased doxorubicin-induced senescence, impaired proliferation in galactose medium, and reduced mitochondrial oxygen consumption.
• Akt2 knockdown did not produce similar effects on mitochondrial parameters.
• Akt3 deficiency impaired mitochondrial respiration in both EJ bladder cancer and A549 lung cancer cells.

Conclusions:

• Akt isoforms exhibit distinct functions in regulating mitochondrial biology.
• Akt3 plays a critical role in maintaining proper mitochondrial respiration and function in human cancer cells.