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Molecular Cell Jul 2020We recently used CRISPRi/a-based chemical-genetic screens and cell biological, biochemical, and structural assays to determine that rigosertib, an anti-cancer agent in...
We recently used CRISPRi/a-based chemical-genetic screens and cell biological, biochemical, and structural assays to determine that rigosertib, an anti-cancer agent in phase III clinical trials, kills cancer cells by destabilizing microtubules. Reddy and co-workers (Baker et al., 2020, this issue of Molecular Cell) suggest that a contaminating degradation product in commercial formulations of rigosertib is responsible for the microtubule-destabilizing activity. Here, we demonstrate that cells treated with pharmaceutical-grade rigosertib (>99.9% purity) or commercially obtained rigosertib have qualitatively indistinguishable phenotypes across multiple assays. The two formulations have indistinguishable chemical-genetic interactions with genes that modulate microtubule stability, both destabilize microtubules in cells and in vitro, and expression of a rationally designed tubulin mutant with a mutation in the rigosertib binding site (L240F TUBB) allows cells to proliferate in the presence of either formulation. Importantly, the specificity of the L240F TUBB mutant for microtubule-destabilizing agents has been confirmed independently. Thus, rigosertib kills cancer cells by destabilizing microtubules, in agreement with our original findings.
Topics: Antineoplastic Agents; Cell Proliferation; Cells, Cultured; Crystallography, X-Ray; Drug Contamination; Glycine; Humans; Microtubules; Mutation; Neoplasms; Pharmaceutical Preparations; Protein Conformation; Sulfones; Tubulin
PubMed: 32619469
DOI: 10.1016/j.molcel.2020.06.008 -
Molecular Cell Jul 2020Rigosertib is a styryl benzyl sulfone that inhibits growth of tumor cells and acts as a RAS mimetic by binding to Ras binding domains of RAS effectors. A recent study...
Rigosertib is a styryl benzyl sulfone that inhibits growth of tumor cells and acts as a RAS mimetic by binding to Ras binding domains of RAS effectors. A recent study attributed rigosertib's mechanism of action to microtubule binding. In that study, rigosertib was obtained from a commercial vendor. We compared the purity of clinical-grade and commercially sourced rigosertib and found that commercially sourced rigosertib contains approximately 5% ON01500, a potent inhibitor of tubulin polymerization. Clinical-grade rigosertib, which is free of this impurity, does not exhibit tubulin-binding activity. Cell lines expressing mutant β-tubulin have also been reported to be resistant to rigosertib. However, our study showed that these cells failed to proliferate in the presence of rigosertib at concentrations that are lethal to wild-type cells. Rigosertib induced a senescence-like phenotype in the small percentage of surviving cells, which could be incorrectly scored as resistant using short-term cultures.
Topics: Antineoplastic Agents; Cell Proliferation; Drug Contamination; Drug Resistance, Neoplasm; Glycine; Humans; Lung Neoplasms; Mutation; Sulfones; Tubulin; Tumor Cells, Cultured
PubMed: 32619468
DOI: 10.1016/j.molcel.2020.05.024 -
Leukemia Research Jul 2020Phase 1 results from a Phase 1/2 study comprise 18 patients with myelodysplastic syndromes (MDS; n = 9), acute myeloid leukemia (AML; n = 8), and chronic myelomonocytic...
Phase 1 results from a Phase 1/2 study comprise 18 patients with myelodysplastic syndromes (MDS; n = 9), acute myeloid leukemia (AML; n = 8), and chronic myelomonocytic leukemia (CMML; n = 1) who were either hypomethylating agent naïve (n = 10) or relapsed/refractory following prior hypomethylating agent therapy (n = 8) (NCT01926587). Patients received oral rigosertib, an inhibitor of Ras-effector pathways, in 3 successive cohorts (140 mg twice daily, 280 mg twice daily, or 840 mg/day [560 mg morning/280 mg evening]) for 3 weeks of a 4-week cycle. Patients received parenteral azacitidine (75 mg/m/day × 7 days) during the second week; the cycle repeated every 4 weeks. The combination was well tolerated for a median of 4 (range 1-41) cycles, with 72% of patients experiencing ≥1 serious adverse events. No dose-limiting toxicities were observed. Thus, no maximum tolerated dose was reached. The most frequently reported adverse events were diarrhea (50%), constipation, fatigue, and nausea (each 44%), and pneumonia and back pain (each 33%). Sequential administration demonstrated an overall response rate of 56% in evaluable patients, with responses observed in 7/9 MDS/CMML patients (78%) and 2/7 AML patients (29%). Further clinical studies are warranted to investigate this doublet therapy in patients with myeloid malignancies.
Topics: Adult; Aged; Aged, 80 and over; Azacitidine; Female; Glycine; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Male; Middle Aged; Myelodysplastic Syndromes; Sulfones
PubMed: 32442785
DOI: 10.1016/j.leukres.2020.106369 -
European Journal of Medicinal Chemistry May 2020RAS-RAF pathway presents a valuable target for the cancer treatment due to its important roles in the regulation of tumor proliferation, apoptosis and the obtained...
RAS-RAF pathway presents a valuable target for the cancer treatment due to its important roles in the regulation of tumor proliferation, apoptosis and the obtained resistance. To explore such target a RAS/CRAF interference agent, was therefore conjugated with Pt(IV) prodrugs via ester bond, resulting in total eleven multifunctional Pt(IV) complexes. The complexes could target genomic DNA and disrupt the signaling transduction from RAS protein to CRAF so that block the mitogen-activated protein kinase (MAPK) signaling pathway. Experiments in vitro indicated that all of the Pt(IV) complexes showed potent anti-tumor activity with IC values ranged from 8 nM to 22.55 μM, which were significantly improved as compared with cisplatin (CDDP) whose IC values ranged from 5.45 μM to 9.05 μM. Among them, 26 exerted the best anti-tumor activity in vitro, which not only exhibited excellent cytotoxicity against normal tumor cells, but also against CDDP-resistance cell lines (e.g. A549/CDDP and SKOV-3/CDDP). Importantly, 26 only showed little effect on normal cell lines such as HUEVC and LO2. Besides, the following biological mechanisms studies demonstrated that 26 could efficiently enter. A549 cells, significantly arrest cell cycle at G2/M phase, disrupt the signaling pathway and trigger endogenous caspase apoptosis pathway. Furthermore, results of a xenograft subcutaneous model of A549 tumor showed that 26 could effectively decrease tumor growth rates without causing loss of bodyweight.
Topics: Antineoplastic Agents; Apoptosis; Cell Cycle Checkpoints; Cell Proliferation; Cells, Cultured; Cisplatin; DNA Damage; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Glycine; Humans; Membrane Potential, Mitochondrial; Molecular Structure; Organoplatinum Compounds; Reactive Oxygen Species; Signal Transduction; Structure-Activity Relationship; Sulfones; raf Kinases; ras Proteins
PubMed: 32248002
DOI: 10.1016/j.ejmech.2020.112269 -
Life Sciences May 2020Rigosertib (RGS) is a PI3K inhibitor that exerts protective effects against tumor progression and cancer-related inflammation. This study was aimed to explore the...
AIMS
Rigosertib (RGS) is a PI3K inhibitor that exerts protective effects against tumor progression and cancer-related inflammation. This study was aimed to explore the regulatory effects of RGS on proliferative, pro-fibrotic and inflammatory factors in DSS- induced colitis mice model.
MATERIALS AND METHODS
The present study integrates systems and molecular biology approaches to investigate the therapeutic potency of RGS in an experimental model of colitis specifically examining its effects on the PI3K/AKT and NF-κB signaling pathways.
KEY FINDINGS
Analysis of time-resolved proteome profiling showed that PI3K-AKT inhibitors regulate expression of many proteins in all stages of inflammation, fibrogenesis and extracellular matrix remodeling. Consistent with our in-silico findings, RGS improved colitis disease activity as assessed by changes in body weight, degree of stool consistency, rectal bleeding and prolapse. RGS also reduced oxidative stress markers and colon histopathological score by decreasing inflammatory responses in colon tissues. Moreover, expression of pro-fibrotic and pro-inflammatory factors including Acta 2, Col 1a1, Col 1a2, IL-1β, TNF-α, INF-γ, and MCP-1 were suppressed in the mice treated with RGS compared to the control group. The protective effects of RGS were mediated by inactivation of PI3K/AKT and NF-kB signaling pathways.
SIGNIFICANCE
This study clearly demonstrates the anti-proliferative, anti-inflammatory and anti-fibrotic effects of RGS in colitis that may have implications for the treatment of colitis and colitis-associated cancer.
Topics: Animals; Antineoplastic Agents; Colitis; Enzyme Inhibitors; Fibrosis; Glycine; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sulfones
PubMed: 32135184
DOI: 10.1016/j.lfs.2020.117470 -
Journal of Medicinal Chemistry Jan 2020Inhibiting/disturbing the RAS/RAF pathway may benefit the treatment of cancer and overcome the resistance. Utilizing such a pathway as the target, nine...
Platinum-Based Modification of Styrylbenzylsulfones as Multifunctional Antitumor Agents: Targeting the RAS/RAF Pathway, Enhancing Antitumor Activity, and Overcoming Multidrug Resistance.
Inhibiting/disturbing the RAS/RAF pathway may benefit the treatment of cancer and overcome the resistance. Utilizing such a pathway as the target, nine styrylbenzylsulfone derivatives generated from the platinum-based modification of the side chain of Rigosertib were designed. Among them, compound showed the most potent antitumor activity in vitro with IC values at the nanomolar level against the tested tumor cell lines and 1000-fold higher than cisplatin against the multidrug resistant cells (A549/CDDP, A549/DOX, and SKOV-3/CDDP cells), while it showed only moderate cytotoxicity against normal cells (HEUVC cells). Compound could clearly disturb signaling transduction between RAS and CRAF by directly bonding to CRAF and inhibit CRAF activation. Besides, the enhanced intracellular platinum level made more potent than cisplatin in DNA damage, reactive oxygen species accumulation, and mitochondrial membrane potential decrease. Moreover, induced apoptosis by the endogenous pathway and efficiently inhibited tumor growth in the A549 xenograft model without side effects.
Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Coordination Complexes; DNA Damage; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; G2 Phase Cell Cycle Checkpoints; Glycine; Human Umbilical Vein Endothelial Cells; Humans; Mice, Inbred BALB C; Neoplasms; Platinum; Proto-Oncogene Proteins c-raf; Reactive Oxygen Species; Signal Transduction; Sulfones; Xenograft Model Antitumor Assays; ras Proteins
PubMed: 31820986
DOI: 10.1021/acs.jmedchem.9b01223 -
Annals of Hematology Sep 2019Rigosertib is a novel multi-kinase inhibitor, which has clinical activity towards leukemic progenitor cells of patients with high-risk myelodysplastic syndromes (MDS)...
Rigosertib is a novel multi-kinase inhibitor, which has clinical activity towards leukemic progenitor cells of patients with high-risk myelodysplastic syndromes (MDS) after failure or progression on hypomethylating agents. Since the bone marrow microenvironment plays an important role in MDS pathogenesis, we investigated the impact of rigosertib on cellular compartments within the osteo-hematopoietic niche. Healthy C57BL/6J mice treated with rigosertib for 3 weeks showed a mild suppression of hematopoiesis (hemoglobin and red blood cells, both - 16%, p < 0.01; white blood cells, - 34%, p < 0.05; platelets, - 38%, p < 0.05), whereas there was no difference in the number of hematopoietic stem cells in the bone marrow. Trabecular bone mass of the spine was reduced by rigosertib (- 16%, p = 0.05). This was accompanied by a lower trabecular number and thickness (- 6% and - 10%, respectively, p < 0.05), partly explained by the increase in osteoclast number and surface (p < 0.01). Milder effects of rigosertib on bone mass were detected in an MDS mouse model system (NHD13). However, rigosertib did not further aggravate MDS-associated cytopenia in NHD13 mice. Finally, we tested the effects of rigosertib on human mesenchymal stromal cells (MSC) in vitro and demonstrated reduced cell viability at nanomolar concentrations. Deterioration of the hematopoietic supportive capacity of MDS-MSC after rigosertib pretreatment demonstrated by decreased number of colony-forming units, especially in the monocytic lineage, further supports the idea of disturbed crosstalk within the osteo-hematopoietic niche mediated by rigosertib. Thus, rigosertib exerts inhibitory effects on the stromal components of the osteo-hematopoietic niche which may explain the dissociation between anti-leukemic activity and the absence of hematological improvement.
Topics: Animals; Glycine; Hematopoiesis; Hematopoietic Stem Cells; Mesenchymal Stem Cells; Mice; Mice, Transgenic; Myelodysplastic Syndromes; Stem Cell Niche; Sulfones
PubMed: 31312928
DOI: 10.1007/s00277-019-03756-1 -
Molecular Pharmaceutics Aug 2019The unbiased cytotoxicity and blood-brain barrier (BBB) impermeability render common chemotherapeutics nonviable for treating glioblastoma (GBM) patients. Although...
The unbiased cytotoxicity and blood-brain barrier (BBB) impermeability render common chemotherapeutics nonviable for treating glioblastoma (GBM) patients. Although rigosertib (RGS), a RAS effector protein inhibitor, has shown low toxicity to healthy cells and high efficacy toward various cancer cells by inactivating PI3K-Akt, it hardly overcomes the BBB barricade. Here, we report that RGS loaded in apolipoprotein E derived peptide (ApoE)-targeted chimaeric polymersomes (ApoE-CP) is safe and highly potent against human GBM in vivo. ApoE-CP exhibited stable loading of RGS in its lumen, giving RGS nanoformulations (ApoE-CP-RGS) with a size of 60 nm and reduction-triggered drug release behavior. Notably, ApoE-CP-RGS induction markedly enhanced the G2/M cell cycle arrest and inhibitory effect in U-87 MG glioblastoma cells compared with the nontargeted CP-RGS and free RGS. The therapeutic outcomes in orthotopic U-87 MG GBM models demonstrated that ApoE-CP-RGS brought about effective GBM inhibition, greatly prolonged survival time, and depleted adverse effects. Rigosertib formulated in ApoE-targeted chimaeric polymersomes has emerged as a novel, highly specific, efficacious, and nontoxic treatment for glioblastoma.
Topics: Animals; Antineoplastic Agents; Apolipoproteins E; Blood-Brain Barrier; Brain Neoplasms; Cell Line, Tumor; Drug Carriers; Drug Liberation; Female; Glioblastoma; Glycine; Humans; Mice; Nanoparticles; Oncogene Proteins; Peptide Fragments; Polymers; Sulfones; Xenograft Model Antitumor Assays
PubMed: 31299161
DOI: 10.1021/acs.molpharmaceut.9b00691 -
Clinical Cancer Research : An Official... Jun 2019Squamous cell carcinoma (SCC) of the skin is the leading cause of death in patients with the severe generalized form of the genetic disease recessive dystrophic...
PURPOSE
Squamous cell carcinoma (SCC) of the skin is the leading cause of death in patients with the severe generalized form of the genetic disease recessive dystrophic epidermolysis bullosa (RDEB). Although emerging data are identifying why patients suffer this fatal complication, therapies for treatment of RDEB SCC are in urgent need. We previously identified polo-like kinase 1 (PLK1) as a therapeutic target in skin SCC, including RDEB SCC. Here, we undertake a screen of 6 compounds originally designated as PLK1 inhibitors, and detail the efficacy of the lead compound, the multipathway allosteric inhibitor ON-01910, for targeting RDEB SCC and .
RESULTS
ON-01910 (or rigosertib) exhibited significant specificity for RDEB SCC: in culture rigosertib induced apoptosis in 10 of 10 RDEB SCC keratinocyte populations while only slowing the growth of normal primary skin cells at doses 2 orders of magnitude higher. Furthermore, rigosertib significantly inhibited the growth of two RDEB SCC in murine xenograft studies with no apparent toxicity. Mechanistically, rigosertib has been shown to inhibit multiple signaling pathways. Comparison of PLK1 siRNA with MEK inhibition, AKT inhibition, and the microtubule-disrupting agent vinblastine in RDEB SCC shows that only PLK1 reduction exhibits a similar sensitivity profile to rigosertib.
CONCLUSIONS
These data support a "first in RDEB" phase II clinical trial of rigosertib to assess tumor targeting in patients with late stage, metastatic, and/or unresectable SCC.
Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle Proteins; Epidermolysis Bullosa Dystrophica; Gene Knockdown Techniques; Genes, Recessive; Glycine; Humans; Keratinocytes; Molecular Targeted Therapy; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; RNA, Messenger; RNA, Small Interfering; Skin Neoplasms; Sulfones; Polo-Like Kinase 1
PubMed: 30846478
DOI: 10.1158/1078-0432.CCR-18-2661 -
Stem Cells and Development Apr 2019Spinal muscular atrophy (SMA) is caused by the mutation or deletion of the survival motor neuron 1 (SMN1) gene. Only ∼10% of the products of SMN2, a paralogue of SMN1,...
Spinal muscular atrophy (SMA) is caused by the mutation or deletion of the survival motor neuron 1 (SMN1) gene. Only ∼10% of the products of SMN2, a paralogue of SMN1, are functional full-length SMN (SMN-FL) proteins, whereas SMN2 primarily produces alternatively spliced transcripts lacking exon 7. Reduced SMN protein levels in SMA patients lead to progressive degeneration of spinal motor neurons (MNs). In this study, we report an advanced platform based on an SMN2 splicing-targeting approach for SMA drug screening and validation using an SMN2 splicing reporter cell line and an in vitro human SMA model through induced pluripotent stem cell (iPSC) technology. Through drug screening using a robust cell-based luciferase assay to quantitatively measure SMN2 splicing, the small-molecule candidate compound rigosertib was identified as an SMN2 splicing modulator that led to enhanced SMN protein expression. The therapeutic potential of the candidate compound was validated in MN progenitors differentiated from SMA patient-derived iPSCs (SMA iPSC-pMNs) as an in vitro human SMA model, which recapitulated the biochemical and molecular phenotypes of SMA, including lower levels of SMN-FL transcripts and protein, enhanced cell death, and reduced neurite length. The candidate compound exerted strong splicing correction activity for SMN2 and potently alleviated the disease-related phenotypes of SMA iPSC-pMNs by modulating various cellular and molecular abnormalities. Our combined screening platform representing a pMN model of human SMA provides an efficient and reliable drug screening system and is a promising resource for drug evaluation and the exploration of drug modes of action.
Topics: Alternative Splicing; Animals; Cell Line; Glycine; Humans; Mice; Mice, Transgenic; Models, Neurological; Muscular Atrophy, Spinal; Sulfones; Survival of Motor Neuron 2 Protein
PubMed: 30667343
DOI: 10.1089/scd.2018.0181