-
Research (Washington, D.C.) 2024Poly (adenosine 5'-diphosphate-ribose) polymerase inhibitors (PARPi) are increasingly important in the treatment of ovarian cancer. However, more than 40% of deficient...
Poly (adenosine 5'-diphosphate-ribose) polymerase inhibitors (PARPi) are increasingly important in the treatment of ovarian cancer. However, more than 40% of deficient patients do not respond to PARPi, and wild-type cases do not show obvious benefit. In this study, we demonstrated that progesterone acted synergistically with niraparib in ovarian cancer cells by enhancing niraparib-mediated DNA damage and death regardless of status. This synergy was validated in an ovarian cancer organoid model and in vivo experiments. Furthermore, we found that progesterone enhances the activity of niraparib in ovarian cancer through inducing ferroptosis by up-regulating palmitoleic acid and causing mitochondrial damage. In clinical cohort, it was observed that progesterone prolonged the survival of patients with ovarian cancer receiving PARPi as second-line maintenance therapy, and high progesterone receptor expression combined with low glutathione peroxidase 4 (GPX4) expression predicted better efficacy of PARPi in patients with ovarian cancer. These findings not only offer new therapeutic strategies for PARPi poor response ovarian cancer but also provide potential molecular markers for predicting the PARPi efficacy.
PubMed: 38798714
DOI: 10.34133/research.0371 -
Microorganisms May 2024In cyanobacteria and chloroplasts (in algae and plants), ATP synthase plays a pivotal role as a photosynthetic membrane complex responsible for producing ATP from... (Review)
Review
In cyanobacteria and chloroplasts (in algae and plants), ATP synthase plays a pivotal role as a photosynthetic membrane complex responsible for producing ATP from adenosine diphosphate and inorganic phosphate, utilizing a proton motive force gradient induced by photosynthesis. These two ATP synthases exhibit similarities in gene organization, amino acid sequences of subunits, structure, and functional mechanisms, suggesting that cyanobacterial ATP synthase is probably the evolutionary precursor to chloroplast ATP synthase. In this review, we explore the precise synthesis and assembly of ATP synthase subunits to address the uneven stoichiometry within the complex during transcription, translation, and assembly processes. We also compare the regulatory strategies governing ATP synthase activity to meet varying energy demands in cyanobacteria and chloroplasts amid fluctuating natural environments. Furthermore, we delve into the role of ATP synthase in stress tolerance and photosynthetic carbon fixation efficiency in oxygenic photosynthetic organisms (OPsOs), along with the current researches on modifying ATP synthase to enhance carbon fixation efficiency under stress conditions. This review aims to offer theoretical insights and serve as a reference for understanding the functional mechanisms of ATP synthase, sparking innovative ideas for enhancing photosynthetic carbon fixation efficiency by utilizing ATP synthase as an effective module in OPsOs.
PubMed: 38792770
DOI: 10.3390/microorganisms12050940 -
International Journal of Molecular... May 2024The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic...
The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic cell death. Overactivation also occurs spontaneously, albeit at a low frequency, in natural populations of spawned frog eggs. Currently, the cytological and biochemical events of the spontaneous process have not been characterized. In the present study, we demonstrate that the spontaneous overactivation of frog eggs, similarly to oxidative stress- and mechanical stress-induced overactivation, is characterized by the fast and irreversible contraction of the egg's cortical layer, an increase in egg size, the depletion of intracellular ATP, a drastic increase in the intracellular ADP/ATP ratio, and the degradation of M phase-specific cyclin B2. These events manifest in eggs in the absence of caspase activation within one hour of triggering overactivation. Importantly, substantial amounts of ATP and ADP leak from the overactivated eggs, indicating that plasma membrane integrity is compromised in these cells. The rupture of the plasma membrane and acute depletion of intracellular ATP explicitly define necrotic cell death. Finally, we report that egg overactivation can occur in the frog's genital tract. Our data suggest that mechanical stress may be a key factor promoting egg overactivation during oviposition in frogs.
Topics: Animals; Adenosine Triphosphate; Ovum; Necrosis; Xenopus laevis; Female; Oxidative Stress; Adenosine Diphosphate; Cell Death; Cell Membrane; Stress, Mechanical
PubMed: 38791359
DOI: 10.3390/ijms25105321 -
Toxins Apr 2024Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR ("NAD- and ADP-ribose"-associated) enzymes reverse guanine ADP-ribosylation...
Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR ("NAD- and ADP-ribose"-associated) enzymes reverse guanine ADP-ribosylation and serve as antitoxins in the DarT-NADAR operon. Although NADARs are widespread across prokaryotes, eukaryotes, and viruses, their specificity and broader physiological roles remain poorly understood. Using phylogenetic and biochemical analyses, we further explore de-ADP-ribosylation activity and antitoxin functions of NADAR domains. We demonstrate that different subfamilies of NADAR proteins from representative strains and an -infecting phage retain biochemical activity while displaying specificity in providing protection from toxic guanine ADP-ribosylation in cells. Furthermore, we identify a myxobacterial enzyme within the YbiA subfamily that functions as an antitoxin for its associated DarT-unrelated ART toxin, which we termed YarT, thus presenting a hitherto uncharacterised ART-YbiA toxin-antitoxin pair. Our studies contribute to the burgeoning field of DNA ADP-ribosylation, supporting its physiological relevance within and beyond bacterial toxin-antitoxin systems. Notably, the specificity and confinement of NADARs to non-mammals infer their potential as highly specific targets for antimicrobial drugs with minimal off-target effects.
Topics: ADP-Ribosylation; Escherichia coli; Escherichia coli Proteins; Bacterial Toxins; Adenosine Diphosphate Ribose; Phylogeny; Toxin-Antitoxin Systems; DNA, Bacterial; DNA
PubMed: 38787060
DOI: 10.3390/toxins16050208 -
Chinese Clinical Oncology May 2024Pancreatic cancer is an aggressive malignancy with high mortality. At the time of diagnosis, majority of patients (80-90%) present with either locally advanced...
BACKGROUND AND OBJECTIVE
Pancreatic cancer is an aggressive malignancy with high mortality. At the time of diagnosis, majority of patients (80-90%) present with either locally advanced unresectable disease or metastatic disease. Even after curative resection, the recurrence rate remains quite high. This article aimed at reviewing the updated management of pancreatic cancer.
METHODS
We identified literature by searching Medline and PubMed from January 2010 to June 2023 using the keywords.
KEY CONTENT AND FINDINGS
A multidisciplinary approach is essential to optimize the outcomes for both curable and advanced diseases. Management of pancreatic cancer divided into resectable, borderline resectable, locally advanced, and metastatic diseases. Surgery and adjuvant chemotherapy is a standard treatment approach for resectable pancreatic cancer. The recommended adjuvant chemotherapy regimen for patients with good functional status is modified FOLFIRINOX (5-fluorouracil, folinic acid, irinotecan, and oxaliplatin). The recommended adjuvant chemotherapy regimen for patients with suboptimal functional status is gemcitabine plus capecitabine or monotherapy gemcitabine. The optimal treatment strategy for borderline resectable pancreatic cancer is still uncertain. Traditionally, upfront surgery is the choice of treatment. There is increasing evidence showing benefits of neoadjuvant therapy in borderline resectable pancreatic cancer. However, the optimal neoadjuvant treatment regimen was not certain yet. Advancement of chemotherapy has a positive impact for the survival of advanced disease. For patients with good functional status, the recommended first-line systemic chemotherapy for unresectable locally advanced disease or metastatic disease is combination chemotherapy regimens such as FOLFIRINOX, gemcitabine plus nabpaclitaxel. For patients with suboptimal functional status, the recommended first-line systemic chemotherapy for unresectable locally advanced disease or metastatic disease is gemcitabine plus capecitabine or monotherapy gemcitabine. Recently, more researches showed promising results in the use of nanoliposomal irinotecan, targeted agents such as a poly [adenosine diphosphate (ADB)-ribose] polymerase inhibitor, tyrosine receptor kinase (TRK) inhibitors, and immune checkpoint-inhibitors.
CONCLUSIONS
Pancreatic cancer is a challenging disease for management. Radical surgery itself is not enough for prolong survival. The improvement of chemotherapy, target agents and immunotherapy with multidisciplinary approach will be the only solution for improvement of survival outcome and quality of life for patients with pancreatic cancer.
PubMed: 38769794
DOI: 10.21037/cco-23-94 -
PLoS Computational Biology May 2024The self-organization of cells relies on the profound complexity of protein-protein interactions. Challenges in directly observing these events have hindered progress...
The self-organization of cells relies on the profound complexity of protein-protein interactions. Challenges in directly observing these events have hindered progress toward understanding their diverse behaviors. One notable example is the interaction between molecular motors and cytoskeletal systems that combine to perform a variety of cellular functions. In this work, we leverage theory and experiments to identify and quantify the rate-limiting mechanism of the initial association between a cargo-bound kinesin motor and a microtubule track. Recent advances in optical tweezers provide binding times for several lengths of kinesin motors trapped at varying distances from a microtubule, empowering the investigation of competing models. We first explore a diffusion-limited model of binding. Through Brownian dynamics simulations and simulation-based inference, we find this simple diffusion model fails to explain the experimental binding times, but an extended model that accounts for the ADP state of the molecular motor agrees closely with the data, even under the scrutiny of penalizing for additional model complexity. We provide quantification of both kinetic rates and biophysical parameters underlying the proposed binding process. Our model suggests that a typical binding event is limited by ADP state rather than physical search. Lastly, we predict how these association rates can be modulated in distinct ways through variation of environmental concentrations and physical properties.
Topics: Kinesins; Protein Binding; Kinetics; Microtubules; Computational Biology; Adenosine Diphosphate; Computer Simulation; Models, Biological; Diffusion
PubMed: 38768214
DOI: 10.1371/journal.pcbi.1012158 -
Plant Molecular Biology May 2024Pyruvate kinase (Pyk, EC 2.7.1.40) is a glycolytic enzyme that generates pyruvate and adenosine triphosphate (ATP) from phosphoenolpyruvate (PEP) and adenosine...
Pyruvate kinase (Pyk, EC 2.7.1.40) is a glycolytic enzyme that generates pyruvate and adenosine triphosphate (ATP) from phosphoenolpyruvate (PEP) and adenosine diphosphate (ADP), respectively. Pyk couples pyruvate and tricarboxylic acid metabolisms. Synechocystis sp. PCC 6803 possesses two pyk genes (encoded pyk1, sll0587 and pyk2, sll1275). A previous study suggested that pyk2 and not pyk1 is essential for cell viability; however, its biochemical analysis is yet to be performed. Herein, we biochemically analyzed Synechocystis Pyk2 (hereafter, SyPyk2). The optimum pH and temperature of SyPyk2 were 7.0 and 55 °C, respectively, and the K values for PEP and ADP under optimal conditions were 1.5 and 0.053 mM, respectively. SyPyk2 is activated in the presence of glucose-6-phosphate (G6P) and ribose-5-phosphate (R5P); however, it remains unaltered in the presence of adenosine monophosphate (AMP) or fructose-1,6-bisphosphate. These results indicate that SyPyk2 is classified as PykA type rather than PykF, stimulated by sugar monophosphates, such as G6P and R5P, but not by AMP. SyPyk2, considering substrate affinity and effectors, can play pivotal roles in sugar catabolism under nonphotosynthetic conditions.
Topics: Synechocystis; Pyruvate Kinase; Phosphoenolpyruvate; Glucose-6-Phosphate; Ribosemonophosphates; Substrate Specificity; Hydrogen-Ion Concentration; Bacterial Proteins; Kinetics; Temperature
PubMed: 38758412
DOI: 10.1007/s11103-023-01401-0 -
Biochemical and Biophysical Research... Aug 2024Poly(ADP-ribose) polymerases (PARPs) are critical to regulating cellular activities, such as the response to DNA damage and cell death. PARPs catalyze a reversible...
Poly(ADP-ribose) polymerases (PARPs) are critical to regulating cellular activities, such as the response to DNA damage and cell death. PARPs catalyze a reversible post-translational modification (PTM) in the form of mono- or poly(ADP-ribosyl)ation. This type of modification is known to form a ubiquitin-ADP-ribose (Ub-ADPR) conjugate that depends on the actions of Deltex family of E3 ubiquitin ligases (DTXs). In particular, DTXs add ubiquitin to the 3'-OH of adenosine ribose' in ADP-ribose, which effectively sequesters ubiquitin and impedes ubiquitin-dependent signaling. Previous work demonstrates DTX function for ubiquitination of protein-free ADPR, mono-ADP-ribosylated peptides, and ADP-ribosylated nucleic acids. However, the dynamics of DTX-mediated ubiquitination of poly(ADP-ribosyl)ation remains to be defined. Here we show that the ADPR ubiquitination function is not found in other PAR-binding E3 ligases and is conserved across DTX family members. Importantly, DTXs specifically target poly(ADP-ribose) chains for ubiquitination that can be cleaved by PARG, the primary eraser of poly(ADP-ribose), leaving the adenosine-terminal ADPR unit conjugated to ubiquitin. Our collective results demonstrate the DTXs' specific ubiquitination of the adenosine terminus of poly(ADP-ribosyl)ation and suggest the unique Ub-ADPR conjugation process as a basis for PARP-DTX control of cellular activities.
Topics: Ubiquitin-Protein Ligases; Ubiquitination; Humans; Adenosine Diphosphate Ribose; Poly ADP Ribosylation; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerases; Ubiquitin; ADP-Ribosylation; HEK293 Cells
PubMed: 38749191
DOI: 10.1016/j.bbrc.2024.150101 -
Experimental and Clinical... Apr 2024Splenectomy during liver transplant can affect platelet function. In this study, our primary aim was to assess the perioperative platelet function by rotational...
Effect of Splenectomy on Coagulation and Platelet Function in Adult Liver Transplant Recipients Assessed With Rotational Thromboelastometry and Standard Coagulation Tests.
OBJECTIVES
Splenectomy during liver transplant can affect platelet function. In this study, our primary aim was to assess the perioperative platelet function by rotational thromboelastometry and the effects of splenectomy on platelet function.
MATERIALS AND METHODS
We studied 40 consecutive liver transplant recipients with end-stage liver disease (50% as a result of hepatitis C). Patients with splenectomy were compared with patients without splenectomy (n = 20/group). Three platelet function parameters by rotational thromboelastometry were studied: platelet activation with arachidonic acid, platelet activation with adenosine diphosphate, and platelet activation with thrombin receptor-activating peptide 6. Patients were monitored perioperatively and until postoperative day 21. Heparin was infused for 2 days postoperatively (60-180 U/kg/day), followed by administration of subcutaneous low-molecular-weight heparin (40 mg/24 h) on postoperative days 2 and 3 and oral acetylsalicylic acid when platelet count was >50 × 103/μL.
RESULTS
Liver disease contributed to low perioperative platelet count and function. Patients showed significant improvement by postoperative day 14 and day 21, particularly after splenectomy. Platelet count was significantly correlated with the 3 platelet function parameters by rotational thromboelastometry (P < .001). Acetyl salicylic acid was required earlier (postoperative day 3) for patients with splenectomy (8/20) but only affected the platelet function represented by platelet activation with arachidonic acid, whereas other platelet activation pathways were less affected. Patients received no transfusions of platelet units.
CONCLUSIONS
End-stage liver disease significantly contributed to low platelet function and counts before transplant. Two weeks were required for recovery of patients posttransplant, with further enhancement by splenectomy. Some recipients showed recovery that exceeded the normal reference range, which warranted monitoring. Acetyl salicylic acid only affected 1 platelet activation receptor.
Topics: Humans; Thrombelastography; Liver Transplantation; Male; Female; Middle Aged; Splenectomy; Treatment Outcome; Blood Coagulation; Adult; End Stage Liver Disease; Time Factors; Blood Platelets; Predictive Value of Tests; Platelet Activation; Platelet Function Tests; Platelet Aggregation Inhibitors; Anticoagulants; Platelet Count; Blood Coagulation Tests; Aspirin; Prospective Studies
PubMed: 38742319
DOI: 10.6002/ect.2023.0329 -
Science Bulletin Apr 2024Ion channel activation upon ligand gating triggers a myriad of biological events and, therefore, evolution of ligand gating mechanism is of fundamental importance....
Ion channel activation upon ligand gating triggers a myriad of biological events and, therefore, evolution of ligand gating mechanism is of fundamental importance. TRPM2, a typical ancient ion channel, is activated by adenosine diphosphate ribose (ADPR) and calcium and its activation has evolved from a simple mode in invertebrates to a more complex one in vertebrates, but the evolutionary process is still unknown. Molecular evolutionary analysis of TRPM2s from more than 280 different animal species has revealed that, the C-terminal NUDT9-H domain has evolved from an enzyme to a ligand binding site for activation, while the N-terminal MHR domain maintains a conserved ligand binding site. Calcium gating pattern has also evolved, from one Ca-binding site as in sea anemones to three sites as in human. Importantly, we identified a new group represented by olTRPM2, which has a novel gating mode and fills the missing link of the channel gating evolution. We conclude that the TRPM2 ligand binding or activation mode evolved through at least three identifiable stages in the past billion years from simple to complicated and coordinated. Such findings benefit the evolutionary investigations of other channels and proteins.
PubMed: 38734586
DOI: 10.1016/j.scib.2024.04.052