Cellular senescence limits translational readthrough

Area of Science:

• Molecular Biology
• Cancer Biology
• Genetics

Background:

• Cancer development is primarily linked to DNA mutations.
• The role of translation errors in cancer remains unclear.
• Caretaker tumor suppressors prevent DNA mutations and promote repair.

Purpose of the Study:

• Investigate if caretaker genes prevent translation errors during oncogenic stress.
• Determine the effect of cellular senescence on translational readthrough (TR).
• Elucidate the role of TR in cancer cell proliferation and escape from senescence.

Main Methods:

• Utilized reporter assays to measure translational readthrough (TR).
• Induced cellular senescence using oncogenes, tumor suppressors, and chemotherapy.
• Analyzed the RB tumor suppressor pathway's role in regulating TR during senescence.
• Assessed TR levels in cells escaping senescence and in breast cancer cells.

Main Results:

• Cellular senescence significantly reduces both basal and aminoglycoside-stimulated TR.
• The RB tumor suppressor pathway mechanistically controls TR reduction during senescence.
• Cells evading oncogene- or chemotherapy-induced senescence exhibit increased TR.
• Breast cancer cells that escape therapy-induced senescence overexpress AGO1x, a TR isoform linked to progression.

Conclusions:

• Senescence and the RB pathway suppress TR, limiting proteome diversity.
• Reduced TR may prevent the expression of TR proteins essential for cancer cell proliferation.
• Increased TR in senescence-escaped cells could contribute to cancer progression.