Gene expression analysis of gallium-resistant and gallium-sensitive lymphoma cells reveals a role for metal-responsive transcription factor-1, metallothionein-2A, and zinc transporter-1 in modulating the antineoplastic activity of gallium nitrate
Bibliographic record
Abstract
Several clinical trials have shown gallium nitrate to be an active agent in the treatment of lymphoma. Whereas gallium is known to target cellular iron homeostasis, the basis for lymphoma cell resistance to gallium is not known. Understanding mechanisms of resistance may suggest strategies to enhance the clinical efficacy of gallium. In the present study, we used a focused DNA microarray to compare the expression of genes related to metal metabolism in gallium-resistant and gallium-sensitive lymphoma cell lines developed by us. Gallium-resistant cells were found to display a marked increase in gene expression for metallothionein-2A and the zinc transporter ZnT-1. Cells exposed to gallium nitrate displayed an increase in the binding of metal-responsive transcription factor-1 to metal response element sequences involved in the transcriptional regulation of metallothionein and ZnT-1 genes. Gallium nitrate induced metallothionein-2A and ZnT-1 expression in cells. A role for metallothionein in modulating the antineoplastic activity of gallium was confirmed by showing that the induction of metallothionein expression by zinc provided partial protection against the cytotoxicity of gallium and by showing that the level of endogenous metallothionein in lymphoma cell lines correlated with their sensitivity to gallium nitrate. Immunohistochemical staining of lymphomatous tissues revealed metallothionein protein to be variably expressed in different lymphomas. Our studies show for the first time that gallium acts on pathways related to zinc metabolism and that metal-responsive transcription factor-1 activity and metallothionein expression contribute to the development of gallium drug resistance. Furthermore, the endogenous level of metallothionein in lymphoma may be an important determinant of clinical response to gallium nitrate.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".