Nuclear localizing sequences promote nuclear translocation and enhance the radiotoxicity of the anti-CD33 monoclonal antibody HuM195 labeled with 111In in human myeloid leukemia cells.
Why this work is in the frame
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Bibliographic record
Abstract
UNLABELLED: Our objective was to evaluate the toxicity of the anti-CD33 monoclonal antibody HuM195 modified with peptides (CGYGPKKKRKVGG) harboring the nuclear localizing sequence (NLS; underlined) of simian virus 40 large T antigen and labeled with (111)In against acute myeloid leukemia (AML) cells. METHODS: HuM195 was derivatized with sulfosuccinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (sulfo-SMCC) to introduce maleimide groups for reaction with NLS-peptides and then conjugated with diethylenetriaminepentaacetic acid for labeling with (111)In. The immunoreactivity of NLS-HuM195 was evaluated by its ability to displace the binding of (111)In-HuM195 to HL-60 leukemia cells. Nuclear localization was measured in HL-60 cells by subcellular fractionation. The antiproliferative effects of (111)In-NLS-HuM195 and (111)In-HuM195 on HL-60, U937, or K562 cells with high, intermediate, or minimal CD33 expression, respectively, were studied. The survival of HL-60 cells or patient AML specimens treated with (111)In-NLS-HuM195 or (111)In-HuM195 was studied. Normal tissue toxicity was evaluated in BALB/c mice injected intravenously with of 3.7 MBq (22 microg) of (111)In-NLS-HuM195 or (111)In-HuM195. RESULTS: NLS-HuM195 exhibited relatively preserved CD33 binding affinity (dissociation constant [K(d)] = 4.3 +/- 1.7 x 10(-9) mol/L to 6.9 +/- 1.3 x 10(-9) mol/L). Nuclear uptake increased from 10.5% +/- 0.5% for (111)In-HuM195 to 28.5% +/- 4.1% or 65.9% +/- 1.5% for (111)In-HuM195 substituted with 4 or 8 NLS-peptides, respectively. The inhibitory concentrations of 50% (IC(50)) and 90% (IC(90)) for HL-60 cells treated with (111)In-NLS-HuM195 were 37 kBq per 10(3) cells and 77-81 kBq per 10(3) cells, respectively. The IC(50) and IC(90) values for (111)In-HuM195 were 92 kBq per 10(3) cells and 203 kBq per 10(3) cells. Growth inhibition was correlated with the level of CD33 expression. The survival of HL-60 cells was reduced from 232 +/- 22 colonies (control) to 7 +/- 1 colonies with 1.48 mBq per cell of (111)In-NLS-HuM195; no colonies were found at 3.33 mBq per cell. The surviving fraction decreased >2-fold in 7 of 9 AML specimens treated with an excess of (111)In-NLS-HuM195 and >10-fold in 2 of these specimens. There were no decreases in body weight or hematologic parameters or increases in alanine aminotransferase or creatinine in mice administered 3.7 MBq (22 microg) of (111)In-NLS-HuM195 or (111)In-HuM195. There was no morphologic damage to the liver or kidneys. CONCLUSION: We conclude that NLS-peptides routed (111)In-HuM195 to the nucleus of AML cells, where the emitted Auger electrons were lethal. (111)In-NLS-HuM195 is a promising targeted radiotherapeutic agent for AML.
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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) | 0.000 | 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) | 0.000 | 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 it