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. Author manuscript; available in PMC: 2022 Mar 8.
Published in final edited form as: Sci Transl Med. 2021 Sep 8;13(610):eabd4811. doi: 10.1126/scitranslmed.abd4811

Fig. 1. Clinically relevant concentrations of paclitaxel cause multipolar spindles without mitotic arrest in breast cancer patients and cells.

Fig. 1.

A) Schematic showing trial design. Research biopsies were obtained prior to paclitaxel treatment and 20 hours after the first dose of paclitaxel. AC = Adriamycin and cyclophosphamide. **indicates that surgery could occur before or after AC, per physician recommendation. B) Representative images of bipolar (top) and multipolar (bottom) mitotic cells in patient tumors before and after paclitaxel treatment. Mitotic cells were identified based on DNA morphology and the presence of a mitotic spindle, labeled by Nuclear Mitotic Apparatus protein (NuMA), which localizes to spindle poles. Pan-cytokeratin was used to discriminate between breast epithelial (tumor) cells and stroma. Scale bar, 5 μm. C-D) Mitotic effects of 80 mg/m2 paclitaxel treatment in primary breast cancer patients. Quantification of (C) multipolar mitotic spindles, defined as containing >2 NuMA foci, and (D) mitotic index before (open circle) and after (arrowhead; the direction indicates increase or decrease) paclitaxel treatment. D, n≥500 cells. For assessment of multipolar spindles in C, mitotic cell sample sizes for patients are 113, 41, 100, 101, 106, 79, 75, 35, 6, 24, 106, 86, and 116 cells, respectively, pre-treatment and 109, 100, 104, 103, 108, 103, 27, 63, 11, 30, 110, 102 and 101 cells, respectively, after treatment. Samples from patients 5 and 10 could not be analyzed due to insufficient tumor tissue collected by biopsy and withdrawal of consent, respectively. E) Images of mitotic spindles with the indicated number of poles in MDA-MB-231 cells after treatment with 10 nM paclitaxel. F) Quantification of mean mitotic index +/− SEM. n≥300 cells from each of 3 independent experiments. G) Quantification of multipolar spindles (mean +/− SD) in Cal51 and MDA-MB-231 cells prior to anaphase onset (n≥100 cells in each of 3 replicates) and in anaphase and telophase (n≥50 cells in each of 3 replicates) in response to 10 nM paclitaxel. H) Quantification of percent daughter cell death from long term timelapse microscopy. n≥50 daughter cells in each of 2 replicates. *P<0.05.