Nrf2 mediates mitochondrial and NADPH oxidase-derived ROS during mild heat stress at 40 °C
Bibliographic record
Abstract
Hyperthermia is an adjuvant to chemotherapy and radiotherapy and sensitizes tumors to these treatments. However, repeated heat treatments result in acquisition of heat resistance (thermotolerance) in tumors. Thermotolerance is an adaptive survival response that appears to be mediated by upregulated cellular defenses. However, the mechanisms of activation remain unclear. When HeLa cells were exposed to mild heat shock at 40 °C for 3 h, levels of superoxide and peroxides increased. Cells were treated with mitochondrial antioxidant MitoQ and NADPH oxidase (NOX) inhibitor apocynin to characterize the contribution of these two sources to the total reactive oxygen species (ROS) pool. We found that both mitochondria and NOX are sources of ROS during mild heat shock at 40 °C. Heat-derived ROS are thought to activate the adaptive survival response at 40 °C. Nrf2, the master regulator of the cellular antioxidant response, is thought to play a pivotal role in establishing the adaptive survival response. Nrf2 was overexpressed or knocked down to assess its role. Moreover, Nrf2 levels correlate with the cellular redox state, and do so via scavenging of mitochondria- and NOX-derived ROS. Knockdown of Nrf2 markedly increased levels of ROS that were scavenged by either apocynin or MitoQ. Finally, critical defense proteins such as DJ-1 and PGAM5 seemed to require a two-key activation system mediated by Nrf2 and mitochondrial ROS. Our study characterized mitochondrial and NOX-derived ROS as being essential in activating cellular defenses alongside Nrf2 and underlines potential therapeutic targets that may contribute to the acquisition of thermotolerance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".