AKT-1, -2, and -3 are expressed in both normal and tumor tissues of the lung, breast, prostate, and colon

Area of Science:

• Molecular biology
• Oncology
• Gene expression analysis

Background:

• The AKT/PKB kinase pathway regulates critical cellular processes, including apoptosis, anoikis, and cell cycle progression, which are often dysregulated in human cancers.
• Three AKT isoforms (AKT-1, -2, and -3) have been identified, with AKT-3 RNA expression previously suggested to be selectively upregulated in hormone-independent breast and prostate cancer cell lines, implying a role in tumor progression.

Purpose of the Study:

• To investigate whether AKT-3 RNA expression is selectively upregulated in human cancers.
• To determine if AKT RNA expression patterns change during tumor development.
• To examine AKT isoform expression across various human cancer cell lines, primary cancers, and normal tissues.

Main Methods:

• Reverse transcription polymerase chain reaction (RT-PCR) was employed to assess AKT-1, -2, and -3 RNA expression.
• Semiquantitative RT-PCR was specifically used to analyze AKT-3 expression levels in matched normal and tumor tissue pairs from colon, breast, prostate, and lung cancers.

Main Results:

• All three AKT isoforms (AKT-1, -2, and -3) were found to be expressed in the vast majority of both normal and tumor tissues examined.
• Semiquantitative RT-PCR analysis of matched normal/tumor pairs revealed comparable AKT-3 RNA expression levels between normal and cancerous tissues.

Conclusions:

• The findings indicate that tumorigenesis does not involve a substantial alteration in the RNA expression patterns of the three AKT isoforms.
• Both normal and tumor tissues consistently express all three AKT isoforms, suggesting a ubiquitous role for these genes rather than specific upregulation in cancer progression.