A new approach for the quantification of mitochondrial DNA damage and repair in prostate cancer cells
Bibliographic record
Abstract
126 As a gold standard for quantification of starting amounts of nucleic acids, real-time PCR is increasingly used in quantitative analysis of mtDNA copy number in medical research. However, the effect of supercoiling on real-time PCR has not been reported. Using supercoiled plasmid DNA and mtDNA modified both in vitro and in cancer cells, we demonstrated that conformational changes in supercoiled DNA have profound influence on real-time PCR quantification. We showed that real-time PCR signal is a positive function of the relaxed forms (open circular and/or linear) rather than the supercoiled form of DNA, and that the conformation transitions mediated by DNA strand breaks are the main basis for sensitive detection of the relaxed DNA. This new finding was then used for sensitive detection of structure-mediated mtDNA damage and repair in stressed prostate cancer cells, and for accurate quantification of total mtDNA copy number when all supercoiled DNA is converted into the relaxed forms using a prior heat-denaturation step. The new approach demonstrated a dynamic mtDNA response to oxidative stress in prostate cancer cells, which involves not only early structural damage and repair but also sustained copy number reduction induced by hydrogen peroxide (H 2 O 2 ). Further analysis of two isogenic prostate cancer cell lines with increasing metastatic potential ( i.e. LNCaP versus C4-2) revealed differential responses to oxidative damage. The C4-2 cell, an androgen-independent and highly metastatic variant, exhibited increased sensitive to H 2 O 2 -induced mtDNA damage than its parental LNCaP cells. The new findings support the notion that invasive prostate cancers are more susceptible to further oxidative injury probably due to a compromised antioxidant defense or an enhanced level of endogenous ROS production, and may offer new strategies for prostate cancer detection and therapy.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".