Novel dual action PARP and microtubule polymerization inhibitor AMXI-5001 powerfully inhibits growth of esophageal carcinoma both alone and in combination with radiotherapy
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SUBMITTER: Brand N
PROVIDER: S-EPMC10839305 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:Poly (ADP-ribose) polymerase (PARP) has recently emerged as a central mediator in cancer resistance against numerous anticancer agents to include chemotherapeutic agents such as microtubule targeting agents and DNA damaging agents. Here, we describe AMXI-5001, a novel, highly potent dual PARP1/2 and microtubule polymerization inhibitor with favorable metabolic stability, oral bioavailability, and pharmacokinetic properties. The potency and selectivity of AMXI-5001 were determined by biochemical assays. Anticancer activity either as a single-agent or in combination with other antitumor agents was evaluated in vitro. In vivo antitumor activity as a single-agent was assessed in a triple-negative breast cancer (TNBC) model. AMXI-5001 demonstrates comparable IC50 inhibition against PARP and microtubule polymerization as clinical PARP inhibitors (Olaparib, Rucaparib, Niraparib, and Talazoparib) and the potent polymerization inhibitor (Vinblastine), respectively. In vitro, AMXI-5001 exhibited selective antitumor cytotoxicity across a wide variety of human cancer cells with much lower IC50s than existing clinical PARP1/2 inhibitors. AMXI-5001 is highly active in both BRCA mutated and wild type cancers. AMXI-5001 is orally bioavailable. AMXI-5001 elicited a remarkable In vivo preclinical anti-tumor activity in a BRCA mutated TNBC model. Oral administration of AMXI-5001 induced complete regression of established tumors, including exceedingly large tumors. AMXI-5001 resulted in superior anti-tumor effects compared to either single agent (PARP or microtubule) inhibitor or combination with both agents. AMXI-5001 will enter clinical trial testing soon and represents a promising, novel first in class dual PARP1/2 and microtubule polymerization inhibitor that delivers continuous and synchronous one-two punch cancer therapy with one molecule.
| S-EPMC7471353 | biostudies-literature
Project description:Purpose: The reported data of elderly ESCC are rather limited and there is a lack of information to guide treatment decisions for elderly patients with esophageal cancer. This study aims to identify the efficacy and factors for optimal treatment approaches for elderly esophageal squamous cell carcinoma (ESCC) treated with radiotherapy (RT) alone or concurrent chemoradiation (CCRT). Methods: This study included 184 I-III elderly ESCC patients aged ≥70 years treated by oral single agent CCRT (sCCRT) or double agents CCRT (dCCRT) or RT alone at a single institution in China. RT was delivered with Intensity Modulated Irradiation Therapy (IMRT) or Volumetric-Modulated Arc Therapy (VMAT). Sequential or simultaneous integrated boost (SIB) approach was applied for GTV dose escalation. Toxicities were evaluated by criteria of Radiation Therapy Oncology Group. Statistical analyses were performed on survival and failure patterns. Results: At a median follow-up time of 15.5 months, the 2- and 3-year estimated overall survival (OS) were 43.5% and 35.2%, respectively. T and N stage, GTV dose (cutoff value 56Gy), simultaneous integrated boost (SIB) technique and CCRT were significant predictors for the outcomes. sCCRT was significantly associated with higher OS, LRFS, and DFS when compared with RT alone and no difference was observed between sCCRT and dCCRT. 44% patients experienced treatment failure, among whom 65.4% developed local failure. 81.3% local failure occurred in GTV and 70.6% regional failures occurred out of radiation field. dCCRT was the only independent prediction factor for grade ≥ 2 neutropenia and gastrointestinal reactions compared with sCCRT and RT alone. No significant difference of toxicities was observed between sCCRT and RT alone. Conclusions: Our results demonstrated that CCRT in elderly patients had significant survival benefit compared to RT alone, especially using Single oral agent. sCCRT had less toxicities compared to dCCRT, and the toxicity was similar to RT alone. GTV dose ≥ 56 Gy and SIB technique were optimal approaches for radiotherapy.
| S-EPMC5665040 | biostudies-literature
Project description:ImportancePalliative radiotherapy (RT) is generally recommended for older patients with esophageal squamous cell carcinoma (ESCC) with poor prognosis. A new combination treatment is therefore needed.ObjectiveTo assess the efficacy and toxicity of RT plus icotinib vs RT alone in older patients with ESCC.Design, setting, and participantsThis randomized, multicenter, open-label, phase II clinical trial was conducted in China, with enrollment between January 1, 2015, and October 31, 2016. Patients aged 70 years or older with clinical stage T2 to T4, N0/1, M0/1a unresectable (because of comorbidities, T4 disease, unresectable lymph node, or refused surgery) ESCC were randomized 1:1 to receive RT plus icotinib or RT alone. Radiation was prescribed at 60 Gy in 30 fractions in both groups, and icotinib was administered at a dosage of 125 mg 3 times a day in the RT plus icotinib group. The last follow-up was completed on June 30, 2019, and data were analyzed from July 1 to September 30, 2019.InterventionsPatients were randomized to either RT plus icotinib or RT alone.Main outcomes and measuresThe primary end point was overall survival (OS). Treatment-related toxic effects were evaluated. Immunohistochemistry was performed to analyze epidermal growth factor receptor (EGFR) expression if available.ResultsA total of 127 patients (median age, 76 years [range, 70-91 years]; 76 men [59.8%]) were enrolled and were eligible for survival analysis. Median OS was 24.0 (95% CI, 22.2-25.8) months in the RT plus icotinib group vs 16.3 (95% CI, 13.8-18.8) months in the RT group (hazard ratio, 0.53; 95% CI, 0.33-0.87; P = .008). No difference was observed in grades 3 or 4 adverse events. Patients with EGFR overexpression had a significantly better median overall survival (not reached vs 16.3 months [range, 2.6-45.1 months]; P = .03) in the RT plus icotinib group.Conclusions and relevanceIn this randomized clinical trial, icotinib plus RT was well tolerated and improved OS in older patients with ESCC relative to RT alone. Patients with EGFR overexpression benefitted more from icotinib with RT.Trial registrationClinicalTrials.gov Identifier: NCT02375581.
| S-EPMC7542309 | biostudies-literature
Project description:Tau is an intrinsically disordered protein with a central role in the pathology of a number of neurodegenerative diseases. Tau normally functions to stabilize neuronal microtubules, although the mechanism underlying this function is not well understood. Of note is that the interaction between tau and soluble tubulin, which has implications both in understanding tau function as well as its role in disease, is underexplored. Here we investigate the relationship between heterogeneity in tau-tubulin complexes and tau function. Specifically, we created a series of truncated and scrambled tau constructs and characterized the size and heterogeneity of the tau-tubulin complexes formed under nonpolymerizing conditions. Function of the constructs was verified by tubulin polymerization assays. We find that, surprisingly, the pseudo-repeat region of tau, which flanks the core microtubule-binding domain of tau, contributes largely to the formation of large, heterogeneous tau tubulin complexes; additional independent tubulin binding sites exist in repeats two and three of the microtubule binding domain. Of particular interest is that we find positive correlation between the size and heterogeneity of the complexes and rate of tau-promoted microtubule polymerization. We propose that tau-tubulin can be described as a "fuzzy" complex, and our results demonstrate the importance of heterogeneous complex formation in tau function. This work provides fundamental insights into the functional mechanism of tau, and more broadly underscores the relevance of heterogeneous and dynamic complexes in the functions of intrinsically disordered proteins.
| S-EPMC5479049 | biostudies-literature
Project description:As a new subtype of breast cancer, molecular apocrine breast cancer (MABC) is estrogen receptor (ER) and progesterone receptor (PR) negative expression, but androgen receptor (AR) positive expression. The prognostic significance and clinical biological behavior of MABC have remained unclear up to now. This study aimed to analysis the distant metastasis behavior and response to adjuvant radiotherapy and chemotherapy of MABC subgroup. The report showed that there were significant differences between early and late distant metastasizing tumors with respect to Ki67, epidermal growth factor receptor 2 (HER2) and vascular endothelial growth factor (VEGF) expressions by a retrospective analysis consisting of 410 invasive breast cancer patients, which included 205 MABC and 205 nonMABC cases. MABC subgroup metastasized earlier than nonMABC subgroup, and MABC showed a tendency for a higher metastasis rate in lung, liver and brain, but lower in bone. HER2-positive or VEGF-positive tumors were more inclined to develop bone metastasis within MABC subgroup. The survival rate was superior for patients undergone both adjuvant radiotherapy and chemotherapy than those undergone chemotherapy alone in nonMABC subgroup, but there was no significant difference in MABC subgroup. Our data suggested that MABC subgroup seemed to develop distant metastasis earlier than nonMABC subgroup, and patients with MABC indicated poor prognosis. This study might also provide a foundation for helping patients receive reasonable treatments according to molecular subtype.
| S-EPMC5226479 | biostudies-literature
Project description:BackgroundTo investigate the survival benefit of concurrent chemoradiotherapy (CCRT) for patients with locally advanced esophageal squamous cell carcinoma (ESCC) during the years of intensity-modulated radiotherapy (IMRT).MethodsMedical records of 1089 patients with ESCC who received IMRT from January 2005 to December 2017 were retrospectively reviewed. A total of 617 patients received CCRT, 472 patients received radiotherapy (RT) alone. Propensity score matching (PSM) method was used to eliminate baseline differences between the two groups. Survival and toxicity profile were evaluated afterward.ResultsAfter a median follow-up time of 47.9 months (3.2-149.8 months), both overall survival (OS) and progression-free survival (PFS) of the CCRT group were better than those of the RT alone group, either before or after PSM. After PSM, the 1-, 3-, and 5-year OS of RT alone and CCRT groups were 59.0% versus 70.2%, 27.7% versus 40.5% and 20.3% versus 33.1%, respectively (p < 0.001). The 1-, 3-, and 5-year PFS were 39.4% versus 49.0%, 18.3% versus 30.4% and 10.5% versus 25.0%, respectively (p < 0.001). The rates of ≥ grade 3 leukopenia and radiation esophagitis in the CCRT group were higher than that of RT alone group (p < 0.05). There was no significant difference in the probability of radiation pneumonitis between the two groups (p = 0.167). Multivariate Cox analysis indicated that female, EQD2 ≥60 Gy and concurrent chemotherapy were favorable prognostic factors for both OS and PFS.ConclusionsConcurrent chemotherapy can bring survival benefits to patients with locally advanced ESCC receiving IMRT. For patients who cannot tolerate concurrent chemotherapy, RT alone is an effective alternative with promising results.
| S-EPMC8201542 | biostudies-literature
Project description:Kinesins are microtubule-dependent motor proteins, some of which moonlight as microtubule polymerases, such as the yeast protein Kip2. Here, we show that the CLIP-170 ortholog Bik1 stabilizes Kip2 at microtubule ends where the motor domain of Kip2 promotes microtubule polymerization. Live-cell imaging and mathematical estimation of Kip2 dynamics reveal that disrupting the Kip2-Bik1 interaction aborts Kip2 dwelling at microtubule ends and abrogates its microtubule polymerization activity. Structural modeling and biochemical experiments identify a patch of positively charged residues that enables the motor domain to bind free tubulin dimers alternatively to the microtubule shaft. Neutralizing this patch abolished the ability of Kip2 to promote microtubule growth both in vivo and in vitro without affecting its ability to walk along microtubules. Our studies suggest that Kip2 utilizes Bik1 as a cofactor to track microtubule tips, where its motor domain then recruits free tubulin and catalyzes microtubule assembly.
| S-EPMC10130750 | biostudies-literature
Project description:Microtubules (MTs) govern actin network remodeling in a wide range of biological processes, yet the mechanisms underlying this cytoskeletal cross-talk have remained obscure. We used single-molecule fluorescence microscopy to show that the MT plus-end-associated protein CLIP-170 binds tightly to formins to accelerate actin filament elongation. Furthermore, we observed mDia1 dimers and CLIP-170 dimers cotracking growing filament ends for several minutes. CLIP-170-mDia1 complexes promoted actin polymerization ~18 times faster than free-barbed-end growth while simultaneously enhancing protection from capping proteins. We used a MT-actin dynamics co-reconstitution system to observe CLIP-170-mDia1 complexes being recruited to growing MT ends by EB1. The complexes triggered rapid growth of actin filaments that remained attached to the MT surface. These activities of CLIP-170 were required in primary neurons for normal dendritic morphology. Thus, our results reveal a cellular mechanism whereby growing MT plus ends direct rapid actin assembly.
| S-EPMC5179141 | biostudies-literature
Project description:PARP was an enzyme found in the nucleus of eukaryotic cells that played a crucial role in repairing damaged DNA. Recently, PARP inhibitors have demonstrated great potential in cancer treatment. Thus, the FDA has approved several small-molecule PARP inhibitors for cancer maintenance therapy. The combination of PARP inhibitors and radiotherapy relies on synthetic lethality, taking advantage of the flaws in DNA repair pathways to target cancer cells specifically. Studies conducted prior to clinical trials have suggested that the combination of PARP inhibitors and radiotherapy can enhance the sensitivity of cancer cells to radiation, intensify DNA damage, and trigger cell death. Combining radiotherapy with PARP inhibitors in clinical trials has enhanced the response rate and progression-free survival of diverse cancer patients. The theoretical foundation of PARP inhibitors combined with radiotherapy is explained in detail in this article, and the latest advances in preclinical and clinical research on these inhibitors for tumor radiotherapy are summarized. The problems in the current field are recognized in our research and potential therapeutic applications for tumors are suggested. Nevertheless, certain obstacles need to be tackled when implementing PARP inhibitors and radiotherapies in clinical settings. Factors to consider when using the combination therapy are the most suitable schedule and amount of medication, identifying advantageous candidates, and the probable adverse effects linked with the combination. The combination of radiotherapy and PARP inhibitors can greatly enhance the effectiveness of cancer treatment.
| S-EPMC10637512 | biostudies-literature
Project description:Thiol oxidation is a probable outcome of cellular oxidative stress and is linked to degenerative disease progression. In addition, protein thiol redox reactions are increasingly identified as a mechanism to regulate protein structure and function. We assessed the effect of hypothiocyanous acid on the cytoskeletal protein tubulin. Total cysteine oxidation by hypothiocyanous and hypochlorous acids was monitored by labeling tubulin with 5-iodoacetamidofluorescein and by detecting higher molecular weight inter-chain tubulin disulfides by Western blot under nonreducing conditions. Hypothiocyanous acid induced nearly stoichiometric oxidation of tubulin cysteines (1.9 mol cysteine/mol oxidant) and no methionine oxidation was observed. Because disulfide reducing agents restored all the polymerization activity that was lost due to oxidant treatment, we conclude that cysteine oxidation of tubulin inhibits microtubule polymerization. Hypothiocyanous acid oxidation of tubulin cysteines was markedly decreased in the presence of 4% glycerol, a component of the tubulin purification buffer. Due to its instability and buffer- and pH-dependent reactivity, hypothiocyanous acid studies require careful consideration of reaction conditions.
| S-EPMC3885989 | biostudies-literature