Jakob, B. | bioRxiv Science

bioRxiv2024

Induction of cytoplasmic dsDNA and cGAS-STING immune signaling after exposure of breast cancer cells to X-rays or high energetic carbon ions

Radiotherapy can trigger activation of the cGAS-STING axis via cytoplasmic dsDNA fragment induction. The activation of cGAS-STING initiates innate immune signaling mediated by interferon type-I that can contribute to eradicate the malignancy. The effect was shown to depend on the fractionation scheme employed. We hypothesized that the innate immune response can also depend on radiation quality because densely ionizing radiation, such as carbon ions, have different effects on DNA lesion quality. We show here that carbon ions induced a significantly higher yield of cytosolic dsDNA fragments per unit dose as compared to photons in an in vitro 4T1 breast cancer model. The higher efficiency also translated in expression and release of interferon-{beta} by the tumor cells. Cytoplasmic dsDNA fragments as well as interferon-{beta} release increased with doses up to 24 Gy and no differences for a fractionation scheme (3x8 Gy) were found as compared to the single high doses of photons. In conclusion, we found that the release of interferon-{beta} after radiation is increasing with the radiation dose up to 20 Gy and that carbon ions have the potential to elicit a strong innate immune signaling.

biophysics↗

bioRxiv2020

X-ray Irradiation activates immune response in human T-lymphocytes by eliciting a Ca2+ signaling cascade

Radiation therapy is efficiently employed for eliminating cancer cells and reducing tumor growth. To further improving its therapeutic application it is mandatory to unravel the molecular effects of ionizing irradiation and to understand whether they support or counteract tumor therapy. Here we examine the impact of X-ray irradiation on immune activation of human T cells with single doses typically employed in tumor therapy. We discover that exposing cells to radiation triggers in a population of leukemic Jurkat T cells and in peripheral blood mononuclear cells (PBMCs) a canonical Ca2+ signaling cascade, which elicits immune activation of these cells. An early step in the signaling cascade is the initiation of sustained oscillations of the cytosolic Ca2+ concentration, an event mediated by store operated Ca2+ entry (SOCE) via an X-ray induced clustering of the Calcium Release-Activated Calcium Modulator 1 with the stromal interaction molecule 1 (Oari1/STIM1). A functional consequence of the Ca2+ signaling cascade is the translocation of the transcription factor nuclear factor of activated T cells (NFAT) from the cytosol into the nucleus where it elicits the expression of genes required for immune activation. These data imply that a direct activation of blood immune cells by ionizing irradiation has an impact on toxicity and therapeutic effects of radiation therapy.

biophysics↗