Pretreatment Chromosomal Instability Correlates With Radiation Sensitivity in Squamous Cell Cancers.

Area of Science:

• Oncology
• Cancer Biology
• Radiation Oncology

Background:

• Chromosomal instability (CIN) is a hallmark of cancer, often linked to treatment resistance and poor prognosis.
• Elevated CIN can lead to cell death, but its role in radiation response is complex.
• Radiation therapy itself can induce CIN, suggesting a potential interplay.

Purpose of the Study:

• To investigate whether pre-existing CIN sensitizes tumor cells to radiation therapy.
• To explore the mechanisms by which CIN affects radiation sensitivity.
• To evaluate the potential of modulating CIN for enhancing radiation efficacy.

Main Methods:

• Engineered isogenic cancer cell lines (FaDu, HeLa) with manipulated Mad1 expression to induce CIN.
• Clonogenic assays and patient-derived xenografts to assess radiation sensitivity in vitro and in vivo.
• MTT assays for drug sensitivity and immunofluorescence microscopy for mitotic error quantification.
• FISH analysis to quantify CIN in patient tumors treated with radiation.

Main Results:

• Higher rates of chromosome missegregation were found to sensitize cells to ionizing radiation.
• Anaphase defects in head and neck cancer xenografts correlated with radiation response.
• Pre-treatment CIN levels in laryngeal cancer predicted improved response to radiation therapy.
• Docetaxel induced radiosensitization by promoting multipolar spindles, not mitotic arrest.

Conclusions:

• CIN mechanistically contributes to radiation response in cancer.
• Increasing CIN is a viable strategy to enhance tumor cell sensitivity to radiation.
• These findings have significant implications for developing personalized radiation therapy approaches.