Oncogene-dependent sloppiness in mRNA translation.

Area of Science:

• Molecular Biology
• Cancer Biology
• Immunology

Background:

• mRNA translation is a fundamental, tightly regulated process for protein synthesis.
• Amino acid scarcity in cancer, specifically melanoma, can trigger aberrant protein production via ribosomal frameshifting.
• The mechanisms and prevalence of this frameshifting phenomenon in cancer remain largely unexplored.

Purpose of the Study:

• To investigate the extent and underlying mechanisms of ribosomal frameshifting induced by amino acid depletion in cancer.
• To explore the relationship between this frameshifting event, termed "sloppiness," and oncogenic signaling pathways.
• To determine if sloppiness has functional implications for cancer immunotherapy.

Main Methods:

• Induction of tryptophan depletion in cancer cell lines.
• Analysis of ribosomal frameshifting events.
• Assessment of MAPK pathway activation and inhibition.
• Investigation of RAS signaling.
• Evaluation of aberrant peptide presentation on cell surfaces.
• T lymphocyte-mediated killing assays.

Main Results:

• Tryptophan depletion induces ribosomal frameshifting (sloppiness) across various cancer types.
• Sloppiness is strongly associated with MAPK pathway hyperactivation.
• RAS activation stimulates sloppiness, while MAPK pathway inhibition suppresses it.
• Drug-resistant cancer cells exhibiting sloppiness present aberrant peptides, enabling T cell recognition and killing.

Conclusions:

• Amino acid starvation-induced ribosomal frameshifting (sloppiness) is a widespread cancer mechanism linked to MAPK pathway activation.
• Sloppiness generates aberrant peptides that can be recognized by T lymphocytes, offering a potential therapeutic vulnerability in drug-resistant cancers.
• Oncogenic signaling, while promoting cancer, inadvertently creates targets through the sloppiness-driven production of aberrant peptides.