FLT3 Expression Is Increased by MEIS1 and Collaborates with NUP98-HOX Fusion Genes in the Induction of Acute Myeloid Leukemia.
Bibliographic record
Abstract
Abstract The TALE family member and HOX cofactor MEIS1 is important in leukemic transformation. MEIS1 has, although non-leukemogenic on its own, been shown to strongly collaborate with several HOX genes and NUP98-HOX fusions to induce acute myeloid leukemia (AML). We have recently described a novel in vitro culture system of cell lines established from murine primary bone marrow cells transduced with the AML-associated fusion gene NUP98-HOXD13 or an engineered NUP98-HOXA10 fusion. These pre-leukemic NUP98-HOX cell lines are transplantable and can efficiently be converted into AML-inducing cells upon MEIS1 transduction. Conveniently, the MEIS1 transduced cells can be purified and preserve their leukemogenic potential even after extensive in vitro expansion. Thus, the availability of the NUP98-HOX cell lines system provided the opportunity to investigate and characterize the mechanism of MEIS1-mediated AML-conversion. Potentially interesting target or candidate genes were screened for expression changes between the parental pre-leukemic lines and AML-inducing MEIS1 transduced cell lines with quantitative RT-PCR and Western blotting. Aberrant expression or mutations of the receptor tyrosine kinase FLT3 gene is a common finding in human AML. Interestingly, Flt3 was found induced 5 to 10 fold in MEIS1 transduced cell lines compared to the parental cell lines. The observed increase in Flt3 expression provided the MEIS1 transduced cells with Flt3 ligand driven growth. This was not seen in the parental cell lines, which could not proliferate with Flt3 ligand as single cytokine or with a MEIS1-homeodomain mutant expressing cell line. Importantly, the Flt3 inhibitor AG1295 could block the proliferative effect of the Flt3 ligand in the MEIS1 transduced cell lines. To test whether Flt3 could substitute for MEIS1-mediated induction of AML in NUP98-HOX pre-leukemic cells, a NUP98-HOXA10 cell line was transduced with an MSCV-Flt3-IRES-YFP construct. The resulting Flt3-transduced cells were shown to express Flt3 at levels similar to that of MEIS1 transduced cells without any significant increase in endogenous Meis1 expression. Transplantation of these cells into mice led to lethal and transplantable AML with a median disease onset of 116 days (n=8) compared to 59 days for MEIS1 (n=4), whereas control transplants remained healthy (n=2). In conclusion, this study demonstrates that MEIS1 can induce Flt3 expression and that Flt3 can collaborate with NUP98-HOX fusion genes in the induction of acute myeloid leukemia. Furthermore, theses results suggest a model in which the leukemogenic synergism of MEIS1 on HOX-mediated leukemia might in part be mediated through FLT3-dependent pathways.
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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".