Gene Expression Analysis Uncovers Possible Resistance Mechanisms to Bortezomib in Mantle Cell Lymphoma That Differ from Mechanisms Identified in Other Lymphoid Malignancies.
Bibliographic record
Abstract
Abstract Bortezomib, a potent inhibitor of the 26S proteasome, has remarkable activity against some lymphoid malignancies, particularly multiple myeloma and mantle cell lymphoma (MCL). The observed 30–50% clinical response rate to bortezomib as a single-agent in relapsed MCL is believed to be mediated mainly by inhibition of the NFkB signaling pathway. Recently, Hsp27 has been shown to confer resistance to bortezomib in a lymphoid cell line. However, much less is known about the mechanisms underlying anti-tumor activity of or resistance to bortezomib in MCL. To address these questions we studied 10 MCL cell lines with t(11;14)(q13;q32) as in vitro models. IC50 values were measured by the MTT cytotoxicity assay for both bortezomib and the BAY 11-7082 compound, a specific inhibitor of the NFkB pathway. The cell lines showed different profiles of response to bortezomib and were grouped according to their IC50 values as sensitive (S) (Granta 519, Jeko-1, SP-49, UPN-1), intermediate (In) (HBL-2, JVM-2, Z-138) and resistant (R) (Mino, NCEB-1, SP-53). The mean IC50 for bortezomib in the R group was 3 times higher than the mean IC50 of the S group. The cell lines also showed very different profiles of response to the NFkB-specific inhibitor BAY 11-7082, but grouped differently, suggesting that other mechanisms, in addition to the NFkB pathway, participate in the anti-neoplastic effect of proteasome inhibition in MCL. Resistance to both drugs had no correlation with P-glycoprotein activity as measured by the rodhamine efflux assay. We performed gene expression profiling on Affymetrix U133A 2.0 arrays of all 10 cell lines. Using GeneSpring software (Agilent), we normalized expression to the mean of the S group and identified 79 transcripts that showed a dose response behavior; that is, genes whose mean expression was 1.5x higher in the In versus the S group and 1.5x higher in the R versus the In group. Conversely, 55 transcripts followed the opposite trend, being down-regulated at least 1.5x in both comparisons. This list contained genes important in apoptosis control and in transmembrane transport, but was most notable for an overexpression of stress response genes in the R group. Notably, expression of Hsp70 was almost 10-fold higher in the R versus S group. We therefore analyzed expression of the HSP70 as well as HSP27 and HSP90 proteins by Western blotting. Hsp70 protein was highly expressed in all MCL cell lines and there was no discernable correlation with bortezomib resistance for any of the HSP-proteins analyzed. Other resistance mechanisms appear more important in MCL and we are currently testing further candidate genes for their ability to confer resistance to bortezomib in MCL.
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 | 0.000 | 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) | 0.002 | 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".