Cell Line-Specific Direct Irradiation and Bystander Responses are Influenced by Fetal Bovine Serum Serotonin Concentrations
Bibliographic record
Abstract
The radiation-induced bystander effect is mechanistically complex, involving many different signaling components. Serotonin, present in fetal bovine serum (FBS), has been implicated in the modulation of cellular responses to radiation. However, the role of this ubiquitous signaling molecule has yet to be elucidated with regard to cell line-specific radiation responses. In this study, cell survival was measured in HCT116 p53 wild-type (HCT116+/+) and HaCaT cell cultures treated with media containing serotonin-depleted FBS and compared to our standard FBS-supplemented media, using clonogenic assays. We utilized an enzyme-linked immunosorbent assay to quantify the difference (4.3 ± 1.3 ng/ml) in serotonin concentrations among the media. Serotonin-depleted media significantly reduced survival in both nonirradiated cell lines. Furthermore, we sought to determine the effects to cells in this media exposed to direct irradiation as well as bystander media from irradiated cells. Cell survival was significantly increased when HCT116+/+ cells were directly irradiated in serotonin-depleted media, while HaCaT cells showed no significant difference in survival between the media. Bystander investigations demonstrated that HCT116+/+ cells were only able to generate a bystander effect when cultured in standard media conditions containing greater serotonin levels. Conversely, HaCaT cells were unaffected by the different media in terms of producing a bystander response, generating bystander effects irrespective of the media. Previous research linking serotonin receptors to the bystander effect, together with our results, indicate that receptor heterogeneity among cell types may underlie serotonin sensitivity in direct irradiation and bystander responses through serotonin receptor-mediated cell signaling cascades.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".