Project description:The lack of a cure for metastatic prostate cancer (PCa) highlights the urgent need for more efficient drugs to fight this disease. Here, we report the molecular mechanism of action of the natural product 6-acetoxy-anopterine (6-AA) in malignant cells of the prostate. This potent cytotoxic alkaloid from the endemic Australian tree Anopterus macleayanus induced at low nanomolar doses a strong accumulation of LNCaP and PC3 PCa cells in mitosis, severe mitotic spindle defects and asymmetric cell divisions, ultimately leading to mitotic catastrophe accompanied by cell death through apoptosis. DNA microarray of 6-AA treated LNCaP cells combined with pathway analysis identified very similar transcriptional changes when compared to vinblastine, highlighting pathways involved in mitosis, microtubule spindle organisation and microtubule binding. Like vinblastine, 6-AA inhibited microtubule polymerization in a cell-free system and reduced microtubule polymer mass in vitro. Yet, microtubule alterations that are associated with resistance to microtubule-destabilizing drugs like vinca alkaloids or 2-methoxyestradiol did not confer cross-resistance to 6-AA, suggesting a different mechanism of microtubule interaction. Finally, 6-AA is the first-in-class microtubule inhibitor that features the unique anopterine scaffold. Altogether, this study provides a strong rationale to further develop this novel structure class of microtubule inhibitor for the treatment of malignant disease.
Project description:NF1 is a tumor suppressor widely mutated across several cancers. Its best characterized function is the inhibition of RAS signaling through its GTPase-Activating Protein (GAP) domain. Additional functions have been proposed but not deeply investigated, due to its large size and complex domain structure. Here, combining patient data, in vitro/in vivo models and protein biochemistry, we show that NF1 is a novel Microtubule-Associated Protein (MAP) that modulates microtubular dynamics and intra-tubular repair. NF1 loss results in mitotic defects such as prolonged mitosis, supranumerary centrosomes and chromosome missegregation, leading to low-grade aneuploidy in cell lines and patients. Loss of NF1-mediated intratubular repair creates a liability specifically targetable by maytansinoids, a class of microtubule-depolymerizing agents widely used as payloads in Antibody-Drug Conjugates such as Trastuzumab-Emtansine (T-DM1). Our results directly imply loss of intratubular repair as a driver of tumorigenesis, and NF1 as the first ADC payload-associated biomarker.
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 27 breast cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included. for eribulin , paclitaxel and untreated cell lines.
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 19 endometrial cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included. for eribulin , paclitaxel and untreated cell lines.
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 21 ovarian cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included for eribulin , paclitaxel and untreated cell lines.
Project description:Introduction: Castrate resistant prostate cancer in men shares several characteristics with late-stage canine prostate cancer. Consequently, dogs became a model organism for the study of the human disease. Due to current insufficient therapies, evaluation of novel therapeutic agents for late-stage prostate cancer is of considerable interest for both species. Methods: In this interdisciplinary study we characterized the influence of two indolylmaleimides (PDA-66 and PDA-377) on human and canine prostate carcinoma cell lines. For this purpose, we analyzed morphology, proliferation and apoptosis, recorded live cell imaging movies and performed whole transcriptome sequencing. Results: While PDA-377 showed only weak growth inhibition on the human prostate cancer cell lines, PDA-66 inhibited proliferation and induced apoptosis in all prostate carcinoma cell lines with concentrations in the low micromolar range. Morphological characterization and whole transcriptome sequencing revealed that PDA-66 induces mitotic death through its microtubule-depolymerizing ability. Discussion: PDA-66 appears to be a worthwhile anti-mitotic agent for further evaluation. The similarities in cellular and molecular response observed in the cell lines of both origins form a solid basis for the use of canine PCa in vivo models to provide valuable transferable findings to the benefit of both species.
Project description:In a genome-wide CRISPR-Cas9 resistance drug screen, we identified the master osmostress regulator WNK1 kinase as a modulator of the response to the mitotic drug rigosertib. Osmotic stress and WNK1 inactivation lead to an altered response not only to rigosertib but also to other microtubule-related drugs, minimizing the prototypical mitotic arrest produced by these drugs. This effect is due to an alteration in microtubule stability and polymerization dynamics, likely maintained by fluctuations in intracellular molecular crowding upon WNK1 inactivation. This promotes resistance to microtubule depolymerizing drugs, and increased sensitivity to microtubule stabilizing drugs. In summary, our data proposes WNK1 osmoregulation activity as a biomarker for microtubule-associated chemotherapy response.
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro.
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro.