Alterations in Mitochondrial and Apoptosis‐regulating Gene Expression in Photodynamic Therapy‐resistant Variants of HT29 Colon Carcinoma Cells<sup>¶</sup>
Bibliographic record
Abstract
ABSTRACT Photodynamic therapy (PDT) is a novel cancer therapy inducing irreversible photodamage to tumor tissue via photosensitizer‐mediated oxidative cytotoxicity. The cellular and molecular responses associated with PDT are only partially understood. We have reported previously the generation of several photosensitizer‐specific PDT‐resistant cell variants of HT29 human colon adenocarcinoma cells by selecting cells from sequential PDT treatment using different photosensitizers. In this report, we describe the use of messenger RNA (mRNA) differential display to identify genes that were differentially expressed in the parental HT29 cells compared with their resistant variants. In comparison with parental HT29 cells, mRNA expression was increased in the PDT‐resistant cell variants for BNIP3, estrogen receptor‐binding fragmentassociated gene 9, Myh‐1c, cytoplasmic dynein light chain 1, small membrane protein I and differential dependent protein. In contrast, expression in the PDT‐resistant variants was downregulated for NNX3, human HepG2 3′region Mbol complementary DNA, glutamate dehydrogenase, hepatomaderived growth factor and the mitochondrial genes coding for 16S ribosomal RNA (rRNA) and nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 4. The reduction for mitochondrial 16S rRNA in the PDT‐resistant variants was confirmed by Northern blotting, and the elevated expression of the proapoptotic BNIP3 in the PDT‐resistant variants was confirmed by Northern and Western blotting analysis. We also examined the expression of some additional apoptosis‐regulating genes using Western blotting. We show an increased expression of Bcl‐2 and heat shock protein 27 and a downregulation of Bax in the PDT‐resistant variants. In addition, the mutant p53 levels in the parental HT29 cells were reduced substantially in the PDT‐resistant variants. We suggest that the altered expression in several mitochondria1 and apoptosisregulating genes contributes to PDT resistance.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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".