The Evolutionarily Conserved Cassette Exon 7b Drives ERG's Oncogenic Properties

Area of Science:

• Molecular Biology
• Cancer Research
• Evolutionary Biology

Background:

• The ERG oncogene, encoding an ETS transcription factor, is vital for development and implicated in various cancers.
• Alternative splicing of ERG, particularly exon 7b inclusion, correlates with increased cell proliferation and advanced prostate cancer.
• Exon 7b's encoded 24 amino acids are evolutionarily conserved, suggesting functional significance.

Purpose of the Study:

• To investigate the functional role of ERG exon 7b in cancer.
• To determine if targeting ERG exon 7b can inhibit cancer progression.

Main Methods:

• Designed splice-switching oligonucleotides (morpholino chemistry) to induce ERG exon 7b skipping.
• Tested the effects of exon 7b skipping in MG63 osteosarcoma and VCaP prostate cancer cells in vitro and in vivo (xenografts).
• Assessed cell proliferation, invasion, apoptosis, and xenograft growth.

Main Results:

• Exon 7b skipping significantly reduced cell proliferation and invasion.
• Induction of apoptosis was observed in vitro following exon 7b skipping.
• Reduced tumor growth in vivo was achieved by skipping ERG exon 7b.
• ERG exon 7b was found to be necessary for inducing tissue nonspecific alkaline phosphatase.

Conclusions:

• The evolutionarily conserved ERG exon 7b is a key driver of oncogenic properties.
• Targeting ERG exon 7b splicing represents a potential therapeutic strategy for ERG-driven cancers.
• Exon 7b plays a critical role in ERG-mediated oncogenesis and cancer progression.