Project description:We transfected HEK-293T cells to express RfA1. The RNA-Seq results indicates that Genes evolved in biological processes such as “regulation of microtubule cytoskeleton organization”, “microtubule polymerization or depolymerization”, “microtubule nucleation” were found to respond to RfA1 expression. Correspondingly, these microtubule relevant genes were also sorted to cellular component items, including “spindle microtubule”, “spindle pole centrosome”, “mitotic spindle”, “spindle” , which indicates the tight relationship between RfA1 and microtubules.
Project description:RNAseq analysis of suprabasal cells in the epidermis of control and K10rtTA;TRESpastin (which depolymerize microtubules) at E16.5 were performed. We observed the premature differentiation of the barrier and increased actomyosin contractility in suprabasal differentiated cells upon microtubule disruption compared to control, and proved the increased actomyosin contractility caused by microtubule depolymerization leads to basal stem cell hyperproliferation during epidermal development.
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:BET inhibitors are promising therapeutic agents for the treatment of triple-negative breast cancer (TNBC), but the rapid emergence of resistance necessitates investigation of combination therapies and their effects on tumor evolution. Here, we show that palbociclib, a CDK4/6 inhibitor, and paclitaxel, a microtubule inhibitor, synergize with the BET inhibitor JQ1 in TNBC lines. High-complexity DNA barcoding and mathematical modeling indicate a high rate of de novo acquired resistance to these drugs relative to pre-existing resistance. We demonstrate that the combination of JQ1 and palbociclib induces cell division errors, which can increase the chance of developing aneuploidy. Characterizing acquired resistance to combination treatment at single cell level shows heterogeneous mechanisms including activation of G1-S and senescence pathways. Our results establish a rationale for further investigation of combined BET and CDK4/6 inhibition in TNBC and suggest novel mechanisms of action for these drugs, and new vulnerabilities in cells after emergence of resistance.
Project description:BET inhibitors are promising therapeutic agents for the treatment of triple-negative breast cancer (TNBC), but the rapid emergence of resistance necessitates investigation of combination therapies and their effects on tumor evolution. Here, we show that palbociclib, a CDK4/6 inhibitor, and paclitaxel, a microtubule inhibitor, synergize with the BET inhibitor JQ1 in TNBC lines. High-complexity DNA barcoding and mathematical modeling indicate a high rate of de novo acquired resistance to these drugs relative to pre-existing resistance. We demonstrate that the combination of JQ1 and palbociclib induces cell division errors, which can increase the chance of developing aneuploidy. Characterizing acquired resistance to combination treatment at single cell level shows heterogeneous mechanisms including activation of G1-S and senescence pathways. Our results establish a rationale for further investigation of combined BET and CDK4/6 inhibition in TNBC and suggest novel mechanisms of action for these drugs, and new vulnerabilities in cells after emergence of resistance.
Project description:This model is built by COPASI 4.24(Build 197), based on paper:
Mathematical Approach to Differentiate Spontaneous and Induced Evolution to Drug Resistance During Cancer Treatment.
Author:
James M. Greene, Jana L. Gevertz, Eduardo D. sontag
Abstract:
PURPOSE:Drug resistance is a major impediment to the success of cancer treatment. Resistance is typically thought to arise from random genetic mutations, after which mutated cells expand via Darwinian selection. However, recent experimental evidence suggests that progression to drug resistance need not occur randomly, but instead may be induced by the treatment itself via either genetic changes or epigenetic alterations. This relatively novel notion of resistance complicates the already challenging task of designing effective treatment protocols. MATERIALS AND METHODS:To better understand resistance, we have developed a mathematical modeling framework that incorporates both spontaneous and drug-induced resistance. RESULTS:Our model demonstrates that the ability of a drug to induce resistance can result in qualitatively different responses to the same drug dose and delivery schedule. We have also proven that the induction parameter in our model is theoretically identifiable and propose an in vitro protocol that could be used to determine a treatment's propensity to induce resistance.
Project description:Swift and complete spindle disassembly in late mitosis is essential for cell survival, yet how it happens is largely unknown in mammalian cells. Here we used real-time live cell microscopy and biochemical assays to show that the primordial dwarfism (PD)-related cysteine-rich protein CRIPT dictates the spindle disassembly in a redox-dependent manner in human cells. This previously reported cytoplasmic protein was found to have a confined nuclear localization with a nucleolar concentration during interphase but was distributed to spindles and underwent redox modifications to form disulfide bonds in CXXC pairs during mitosis. Then, it directly interacted with, and might transfer a redox response to, tubulin subunits via a putative redox exchange among cysteine residues to induce microtubule depolymerization. Expression of CRIPT proteins with mutations of these cysteine residues blocked spindle disassembly, generating two cell types with long-lasting metaphase spindles or spindle remnants. Live-cell recordings of a disease-relevant mutant (CRIPTC3Y) revealed that microtubule depolymerization at spindle ends during anaphase and the entire spindle dissolution during telophase might share a common CRIPT-bearing redox-controlled mechanism.
Project description:Two conditions experiment, ChIP-chip anti-Sir3 comparing Sir3 occupancy in exponentially growing S.cerevisiae cells to Sir3 occupancy in the dense fraction of 7 days YPD culture of S.cerevisiae
Project description:A chimeric fusion between the RNA binding protein EWS and the ETS family transcription factor FLI1 (EWS-FLI1), created from a chromosomal translocation, is implicated in driving the majority of Ewing sarcomas (ES) by modulation of transcription and alternative splicing. The small molecule YK-4-279 inhibits EWS-FLI1 function and induces apoptosis. We tested 69 anti-cancer drugs in combination with YK-4-279 and found that vinca alkaloids exhibited synergy with YK-4-279 in five ES cell lines. The combination of YK-4-279 and vincristine reduced tumor burden and increased survival in mice bearing ES xenografts. We determined that independent drug-induced events converged to cause this synergistic therapeutic effect. YK-4-279 rapidly induced G2/M arrest, increased the abundance of cyclin B1, and decreased EWS-FLI1–mediated expression of microtubule-associated proteins, which rendered cells more susceptible to microtubule depolymerization by vincristine. YK-4-279 reduced the expression of the EWS-FLI1 target gene encoding ubiquitin ligase UBE2C, and this in part contributed to the increase in cyclin B1. Biochemical assays revealed that YK-4-279 also increased the abundance of proapoptotic isoforms of MCL1 and BCL2, presumably through inhibition of alternative splicing by EWS-FLI1, thus promoting cell death in response to vincristine. Thus a combination of vincristine and YK-4-279 might be therapeutically effective in ES patients.