Detection of Dysfunctional Telomeres in Oncogene-Induced Senescence

Area of Science:

• Cellular senescence
• DNA damage response
• Telomere biology

Background:

• Oncogene expression in human cells induces cellular senescence.
• This oncogene-induced senescence (OIS) involves a DNA damage response (DDR) due to DNA lesions at telomeric and non-telomeric sequences.
• While non-telomeric DNA damage foci resolve, telomeric foci (dysfunctional telomeres) persist during OIS.

Purpose of the Study:

• To describe a protocol for detecting dysfunctional telomeres.
• To monitor the accumulation of dysfunctional telomeres during OIS.
• To enable detection of dysfunctional telomeres in fixed human tissues.

Main Methods:

• Immunofluorescence microscopy using DDR factors like ϒ-H2AX and 53BP1 to visualize DNA lesions.
• Protocol development for detecting dysfunctional telomeres in cultured cells.
• Adaptation of the protocol for paraffin-embedded, formalin-fixed human tissues.

Main Results:

• Dysfunctional telomeres, visualized as persistent DDR foci, accumulate during OIS.
• The developed protocol effectively detects these dysfunctional telomeres in various cellular and tissue contexts.
• This method allows for temporal monitoring of telomere dysfunction in senescence.

Conclusions:

• Dysfunctional telomeres are persistent markers of oncogene-induced senescence.
• The described protocol provides a robust method for studying telomere dysfunction in OIS.
• This technique is applicable to both cell cultures and clinical tissue samples.