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Journal of Thrombosis and Haemostasis :... Jul 2024
Topics: Humans; Vitamin K; Perioperative Care; Anticoagulants; Blood Coagulation
PubMed: 38945667
DOI: 10.1016/j.jtha.2024.04.012 -
Methods in Enzymology 2024Prenyltransferases are terpene synthases that combine 5-carbon precursor molecules into linear isoprenoids of varying length that serve as substrates for terpene...
Prenyltransferases are terpene synthases that combine 5-carbon precursor molecules into linear isoprenoids of varying length that serve as substrates for terpene cyclases, enzymes that catalyze fascinating cyclization reactions to form diverse terpene natural products. Terpenes and their derivatives comprise the largest class of natural products and have myriad functions in nature and diverse commercial uses. An emerging class of bifunctional terpene synthases contains both prenyltransferase and cyclase domains connected by a disordered linker in a single polypeptide chain. Fusicoccadiene synthase from Phomopsis amygdali (PaFS) is one of the most well-characterized members of this subclass and serves as a model system for the exploration of structure-function relationships. PaFS has been structurally characterized using a variety of biophysical techniques. The enzyme oligomerizes to form a stable core of six or eight prenyltransferase domains that produce a 20-carbon linear isoprenoid, geranylgeranyl diphosphate (GGPP), which then transits to the cyclase domains for the generation of fusicoccadiene. Cyclase domains are in dynamic equilibrium between randomly splayed-out and prenyltransferase-associated positions; cluster channeling is implicated for GGPP transit from the prenyltransferase core to the cyclase domains. In this chapter, we outline the methods we are developing to interrogate the nature of cluster channeling in PaFS, including enzyme activity and product analysis assays, approaches for engineering the linker segment connecting the prenyltransferase and cyclase domains, and structural analysis by cryo-EM.
Topics: Alkyl and Aryl Transferases; Dimethylallyltranstransferase; Diterpenes; Enzyme Assays; Polyisoprenyl Phosphates; Cyclization
PubMed: 38942517
DOI: 10.1016/bs.mie.2023.11.003 -
Methods in Enzymology 2024Coral terpenes are important molecules with numerous applications. Here, we describe a robust and simple method to produce coral terpene scaffolds at scale. As an...
Coral terpenes are important molecules with numerous applications. Here, we describe a robust and simple method to produce coral terpene scaffolds at scale. As an example of the approach, here we discover, express, and characterize further klysimplexin R synthases, expanding the known enzymology of soft coral terpene cyclases. We hope that the underlying method described will enable widespread basic research into the functions of coral terpenes and their biosynthetic genes, as well as the commercial development of biomedically and technologically important molecules.
Topics: Anthozoa; Terpenes; Animals; Saccharomyces cerevisiae; Escherichia coli; Alkyl and Aryl Transferases
PubMed: 38942511
DOI: 10.1016/bs.mie.2024.03.023 -
Methods in Enzymology 2024Terpenes comprise the largest class of natural products and are used in applications spanning the areas of medicine, cosmetics, fuels, flavorings, and more. Copalyl...
Terpenes comprise the largest class of natural products and are used in applications spanning the areas of medicine, cosmetics, fuels, flavorings, and more. Copalyl diphosphate synthase from the Penicillium genus is the first bifunctional terpene synthase identified to have both prenyltransferase and class II cyclase activities within the same polypeptide chain. Prior studies of bifunctional terpene synthases reveal that these systems achieve greater catalytic efficiency by channeling geranylgeranyl diphosphate between the prenyltransferase and cyclase domains. A molecular-level understanding of substrate transit phenomena in these systems is highly desirable, but a long disordered polypeptide segment connecting the prenyltranferase and cyclase domains thwarts the crystallization of full-length enzymes. Accordingly, these systems are excellent candidates for structural analysis using cryo-electron microscopy (cryo-EM). Notably, these systems form hexameric or octameric oligomers, so the quaternary structure of the full-length enzyme may influence substrate transit between catalytic domains. Here, we describe methods for the preparation of bifunctional hexameric copalyl diphosphate synthase from Penicillium fellutanum (PfCPS). We also outline approaches for the preparation of cryo-EM grids, data collection, and data processing to yield two-dimensional and three-dimensional reconstructions.
Topics: Penicillium; Alkyl and Aryl Transferases; Cryoelectron Microscopy; Diterpenes; Fungal Proteins; Dimethylallyltranstransferase
PubMed: 38942500
DOI: 10.1016/bs.mie.2023.11.002 -
Cell Biochemistry and Function Jul 2024Multidrug resistance (MDR) during clinical chemotherapy for cancer has been considered a major obstacle to treatment efficacy. The involvement of adenosine...
Multidrug resistance (MDR) during clinical chemotherapy for cancer has been considered a major obstacle to treatment efficacy. The involvement of adenosine triphosphate-binding cassette (ABC) transporters in the MDR mechanism significantly reduces the efficacy of chemotherapeutics. This study investigates the potential of morin, a dietary bioflavonoid, to overcome colchicine resistance in KBChR-8-5 MDR cells. The P-gp inhibitory activity by morin was measured by calcein-AM drug efflux assay. Western blot analysis was employed to evaluate P-gp messenger RNA and protein expressions following morin treatment. Flow cytometry analysis and acridine orange/ethidium bromide fluorescence staining were utilised to investigate the induction of apoptosis and cell cycle arrest upon treatment with morin and paclitaxel in combination. Additionally, polymerase chain reaction (PCR) array analysis was conducted to study the gene expression profiles related to MDR, apoptosis and cell cycle arrest during treatment with morin, paclitaxel or their combination. Morin exhibited a strong binding interaction with human P-gp. This was corroborated by drug efflux assays, which showed a reduction in P-gp efflux function with increasing morin concentration. Furthermore, morin and paclitaxel combination potentiated the induction of apoptosis and G2/M phase cell cycle arrest. Morin treatment significantly downregulated the gene expression of ABCB1 and P-gp membrane expressions in MDR cells. Additionally, PCR array gene expression analysis revealed that the combination treatment with morin and paclitaxel upregulated proapoptotic and cell cycle arrest genes while downregulating ABCB1 gene and antiapoptotic genes. Thus, morin effectively reversed paclitaxel resistance in KBChR-8-5 drug-resistant cancer cells and concluded that morin resensitized the paclitaxel resistance in KBChR8-5 drug-resistant cancer cells.
Topics: Humans; Flavonoids; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Apoptosis; Paclitaxel; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Line, Tumor; Cell Cycle Checkpoints; ATP Binding Cassette Transporter, Subfamily B; Antineoplastic Agents; Flavones
PubMed: 38938150
DOI: 10.1002/cbf.4083 -
BMC Cancer Jun 2024Evaluation publications typically summarize the results of studies to demonstrate the effectiveness of an intervention, but little is shared concerning any changes... (Randomized Controlled Trial)
Randomized Controlled Trial
Process evaluation protocol plan for a home-based physical activity intervention versus educational intervention for persistent taxane-induced peripheral neuropathy (B-HAPI study): a randomized controlled trial.
BACKGROUND
Evaluation publications typically summarize the results of studies to demonstrate the effectiveness of an intervention, but little is shared concerning any changes implemented during the study. We present a process evaluation protocol of a home-based gait, balance, and resistance exercise intervention to ameliorate persistent taxane-induced neuropathy study according to 7 key elements of process evaluation.
METHODS
The process evaluation is conducted parallel to the longitudinal, randomized control clinical trial examining the effects of the home-based gait, balance, and resistance exercise program for women with persistent peripheral neuropathy following treatment with taxanes for breast cancer (IRB approval: Pro00040035). The flowcharts clarify how the intervention should be implemented in comparable settings, fidelity procedures help to ensure the participants are comfortable and identify their individual needs, and the process evaluation allows for the individual attention tailoring and focus of the research to avoid protocol deviation.
CONCLUSIONS
The publication of the evaluation protocol plan adds transparency to the findings of clinical trials and favors process replication in future studies. The process evaluation enables the team to systematically register information and procedures applied during recruitment and factors that impact the implementation of the intervention, thereby allowing proactive approaches to prevent deviations from the protocol. When tracking an intervention continuously, positive or negative intervention effects are revealed early on in the study, giving valuable insight into inconsistent results. Furthermore, a process evaluation adds a participant-centered element to the research protocols, which allows a patient-centered approach to be applied to data collection.
TRIAL REGISTRATION
ClinicalTrials.gov NCT04621721, November 9, 2020, registered prospectively.
PROTOCOL VERSION
April 27, 2020, v2.
Topics: Humans; Peripheral Nervous System Diseases; Female; Breast Neoplasms; Taxoids; Exercise Therapy; Patient Education as Topic; Exercise; Bridged-Ring Compounds; Longitudinal Studies; Research Design; Randomized Controlled Trials as Topic
PubMed: 38937667
DOI: 10.1186/s12885-024-12444-x -
In Vivo (Athens, Greece) 2024Treatment options are limited, and the prognosis is poor for patients with platinum-resistant recurrent metastatic (R/M) head and neck squamous cell carcinoma (HNSCC)....
BACKGROUND
Treatment options are limited, and the prognosis is poor for patients with platinum-resistant recurrent metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). This study evaluated the efficacy and safety of a paclitaxel and ifosfamide (TI) regimen in patients with R/M HNSCC whose disease had progressed following platinum-based therapy.
PATIENTS AND METHODS
In this retrospective study, we included 53 patients with R/M HNSCC who underwent at least one cycle of TI-based therapy, post platinum failure, between February 2020 and August 2023. Some patients received the TI regimen in combination with immunotherapy and/or cetuximab. Key metrics assessed included the objective response rate (ORR), disease control rate, and progression-free as well as overall survival.
RESULTS
The study observed an ORR of 15.8% and a disease control rate of 36.8%. The median progression-free survival for the entire cohort was 3.3 months, and the median overall survival was 9.6 months. Notably, the combination of TI with immunotherapy yielded a higher ORR of 30.8%, compared to 14.3% with TI alone. The most prevalent grade 1-2 adverse events were anemia (81%), weight loss (68%) and hypernatremia (55%).
CONCLUSION
The TI-based regimen demonstrated favorable efficacy and safety profile in treating R/M HNSCC. Enhanced outcomes may be attainable when combining it with immunotherapy. This study suggests that TI-based therapy could serve as a potential salvage option for this specific patient group.
Topics: Humans; Male; Female; Middle Aged; Aged; Salvage Therapy; Head and Neck Neoplasms; Drug Resistance, Neoplasm; Paclitaxel; Antineoplastic Combined Chemotherapy Protocols; Neoplasm Recurrence, Local; Adult; Ifosfamide; Retrospective Studies; Squamous Cell Carcinoma of Head and Neck; Platinum; Neoplasm Metastasis; Aged, 80 and over; Treatment Outcome
PubMed: 38936932
DOI: 10.21873/invivo.13644 -
In Vivo (Athens, Greece) 2024Treatment with taxanes can result in chemotherapy-induced peripheral neuropathy (CIPN). We investigated the efficacy and safety of mirogabalin for the treatment of CIPN...
BACKGROUND/AIM
Treatment with taxanes can result in chemotherapy-induced peripheral neuropathy (CIPN). We investigated the efficacy and safety of mirogabalin for the treatment of CIPN in patients who had been administered perioperative chemotherapy including taxane-based agents for breast cancer.
PATIENTS AND METHODS
We retrospectively analyzed the case of 43 patients with early breast cancer who received a taxane as perioperative chemotherapy and were administered mirogabalin at the diagnosis of CIPN.
RESULTS
Thirty-six patients (83.7%) had grade 1 CIPN and the other seven patients (16.3%) had grade 2 CIPN. The median mirogabalin dose was 10 mg (5-30 mg). CIPN improved from grade 1 to 0 in 12 patients (27.9%) and from grade 2 to 1 in one patient (2.3%); 13 (30.2%) patients thus had an objective therapeutic response. There were no cases in which chemotherapy was reduced or discontinued due to CIPN. Adverse events were evaluated by Common Terminology Criteria for Adverse Events and included five cases of dizziness (11.7%), three of somnolence (7.0%), and two of nausea (4.7%), all of which were grade ≤2. There were no cases of serious (grade ≥3) adverse effects.
CONCLUSION
Mirogabalin may be effective and safe for treating CIPN of patients who receive a taxane in a perioperative breast cancer setting.
Topics: Humans; Female; Breast Neoplasms; Peripheral Nervous System Diseases; Middle Aged; Taxoids; Aged; Adult; Treatment Outcome; Antineoplastic Combined Chemotherapy Protocols; Retrospective Studies; Bridged Bicyclo Compounds; Neoplasm Staging; Perioperative Care; Antineoplastic Agents; Bridged-Ring Compounds
PubMed: 38936921
DOI: 10.21873/invivo.13649 -
PloS One 2024Mucosal-delivered drugs have to pass through the mucus layer before absorption through the epithelial cell membrane. Although there has been increasing interest in...
Mucosal-delivered drugs have to pass through the mucus layer before absorption through the epithelial cell membrane. Although there has been increasing interest in polymeric mucins, a major structural component of mucus, potentially acting as important physiological regulators of mucosal drug absorption, there are no reports that have systematically evaluated the interaction between mucins and drugs. In this study, we assessed the potential interaction between human polymeric mucins (MUC2, MUC5B, and MUC5AC) and various drugs with different chemical profiles by simple centrifugal method and fluorescence analysis. We found that paclitaxel, rifampicin, and theophylline likely induce the aggregation of MUC5B and/or MUC2. In addition, we showed that the binding affinity of drugs for polymeric mucins varied, not only between individual drugs but also among mucin subtypes. Furthermore, we demonstrated that deletion of MUC5AC and MUC5B in A549 cells increased the cytotoxic effects of cyclosporin A and paclitaxel, likely due to loss of mucin-drug interaction. In conclusion, our results indicate the necessity to determine the binding of drugs to mucins and their potential impact on the mucin network property.
Topics: Humans; Paclitaxel; Mucin 5AC; A549 Cells; Drug Interactions; Mucin-5B; Mucins; Mucin-2; Rifampin; Cyclosporine; Protein Binding
PubMed: 38935605
DOI: 10.1371/journal.pone.0306058 -
Natural Product Research Jun 2024One previously undescribed abietane diterpene alkaloid containing an oxazole ring (), one unreported abietane diterpene (), and nine known abietane diterpenes () were...
One previously undescribed abietane diterpene alkaloid containing an oxazole ring (), one unreported abietane diterpene (), and nine known abietane diterpenes () were isolated from the roots and rhizomes of Diels. Their structures and absolute configurations were elucidated by a combination of HRESIMS, 1D and 2D NMR, and ECD. All compounds were evaluated for their cytotoxic activity against several human cancer cell lines (HepG2, A549, H460, MCF7, PC3, and Hela). The results showed that exhibited a moderate cytotoxic effect on HepG2 cells (IC: 14.22 ± 1.05 μM) and was able to inhibit the cell growth of MCF7 and Hela cells by 35.08% and 47.26% respectively, at a concentration of 20 μM, while other compounds showed low cytotoxic activity.
PubMed: 38934460
DOI: 10.1080/14786419.2024.2372829