Protein Inhibitor Research Articles

Mitochondria and Acute Leukemia: A Clinician's Perspective.

Acute leukemia is a group of aggressive hematological malignancies, with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) being the most common types. The biology of acute leukemia involves complex genetic and epigenetic alterations that lead to uncontrolled cell proliferation and resistance to apoptosis. Mitochondrial dysfunction is a feature of acute leukemia that results in altered energy production, unregulated cell death pathways, and increased cancer cell survival. Apoptosis, particularly via the mitochondrial pathway, is crucial for cellular homeostasis and cancer prevention. In acute leukemia, disruption of apoptosis is pivotal in disease development and progression, with elevated levels of anti-apoptotic proteins conferring a survival advantage to leukemia cells and promoting resistance to conventional therapies. Targeting mitochondrial apoptosis using BH3 mimetics and anti-apoptotic protein inhibitors is a viable therapeutic strategy. Alterations in the mitochondrial membrane potential, metabolism, and dynamics also contribute to the pathogenesis of acute leukemia. Continued research is vital for developing novel therapies and enhancing survival outcomes in patients with acute leukemia while minimizing the long-term adverse effects of treatment. In this narrative review, we provide a birds-eye view of the available scientific literature on the importance of mitochondria in acute leukemia, and discuss the role of BH3 mimetics in targeting the mitochondrial internal apoptotic machinery.

A Novel Rational PROTACs Design and Validation via AI-Driven Drug Design Approach.

The rational design of novel drug candidates presents a formidable challenge in modern drug discovery. Proteolysis-targeting chimeras (PROTACs) drug design is particularly demanding due to their limited crystal structure availability and design of a viable small molecule to bridge the protein of interest (POI) and ubiquitin-protein ligase (E3). An integrated approach that combines superimposition techniques and deep neural networks is demonstrated in this study to leverage the power of deep learning and structural biology to generate structurally diverse molecules with enhanced binding affinities. The superimposition technique ensures the congruence of initial and new protein-ligand pairs, which are evaluated via subsequent comprehensive screening using the root-mean-square deviation (RMSD), binding free energy (BFE), and buried solvent-accessible surface area (SASA). The final candidates are subjected to the incorporation of molecular dynamics (MD) and free energy perturbation (FEP) simulations to provide a quantitative evaluation of relative binding energies, reinforcing the efficacy and reliability of the generated molecules. The outcomes of the generated novel PROTACs molecules exhibit comparable structural attributes while demonstrating superior binding affinities within the binding pockets when contrasted with those of the established cocrystal ternary complexes. To enhance the generalizability of the workflow, we chose the ternary structure of the cellular inhibitor of apoptosis protein 1 (cIAP1) and Bruton's Tyrosine Kinase (BTK) for validating the chemical properties generated from the processes. The new linker molecules additionally showed superior affinity from the simulations. In summary, this methodology serves as an effective workflow to align computational predictions with current limitations, thereby introducing a novel paradigm in AI-driven drug design.

Reversible and effective cell cycle synchronization method for studying stage-specific investigations.

The cell cycle is a crucial process for cell proliferation, differentiation, and development. Numerous genes and proteins play pivotal roles at specific cell cycle stages to regulate these events precisely. Studying the stage-specific functions of the cell cycle requires accumulating cell populations at the desired cell cycle stage. Cell synchronization, achieved through the use of cell cycle kinase and protein inhibitors, is often employed for this purpose. However, suboptimal concentrations of these inhibitors can result in reduced efficiency, irreversibility, and undesirable cell cycle defects. In this study, we have optimized effective and reversible techniques to synchronize the cell cycle at each stage in human RPE1 cells, utilizing both fixed high-precision cell cycle identification methods and high-temporal live-cell imaging. These reproducible synchronization methods are invaluable for investigating the regulatory mechanisms specific to each cell cycle stage.

Stabilization of interdomain closure by a G protein inhibitor.

Inhibitors of heterotrimeric G proteins are being developed as therapeutic agents. Epitomizing this approach are YM-254890 (YM) and FR900359 (FR), which are efficacious in models of thrombosis, hypertension, obesity, asthma, uveal melanoma, and pain, and under investigation as an FR-antibody conjugate in uveal melanoma clinical trials. YM/FR inhibits the Gq/11/14 subfamily by interfering with GDP (guanosine diphosphate) release, but by an unknown biophysical mechanism. Here, we show that YM inhibits GDP release by stabilizing closure between the Ras-like and α-helical domains of a Gα subunit. Nucleotide-free Gα adopts an ensemble of open and closed configurations, as indicated by single-molecule Förster resonance energy transfer and molecular dynamics simulations, whereas GDP and GTPγS (guanosine 5'-O-[gamma-thio]triphosphate) stabilize distinct closed configurations. YM stabilizes closure in the presence or absence of GDP without requiring an intact interdomain interface. All three classes of mammalian Gα subunits that are insensitive to YM/FR possess homologous but degenerate YM/FR binding sites, yet can be inhibited upon transplantation of the YM/FR binding site of Gq. Novel YM/FR analogs tailored to each class of G protein will provide powerful new tools for therapeutic investigation.

Mpox treatment evolution: past milestones, present advances, and future directions.

An underestimated worldwide health concern, Monkeypox (Mpox) is becoming a bigger menace to the world's population. After smallpox was eradicated in 1970, Mpox was found in a rural region of Africa and quickly spread to other African countries. The etiological agent of the Mpox infection, the Mpox virus, is constantly evolving, and its capability for cross-species transmission led to a global outbreak in 2022 which led to several deaths throughout the world. This review aims to showcase the progressive treatment methods and emerging innovations in the diagnostic and prevention strategies for controlling Mpox. The clinical trial data for antiviral drugs were systematically collected and analyzed using statistical tests to determine the most effective antiviral treatment. Emerging viral protein inhibitors that are under investigation for Mpox treatment were also scrutinized in this review. Additionally, modern diagnostic methods, such as the Streamlined CRISPR On Pod Evaluation platform (SCOPE) and graphene quantum rods were reviewed, and the efficacy of mRNA vaccines with traditional smallpox vaccines used for Mpox were compared. The statistical analysis revealed that tecovirimat (TCV) is the most effective antiviral drug among the other evaluated drugs, showing superior efficacy in clinical trials. Similarly, mRNA vaccines offer greater effectiveness compared to conventional smallpox vaccines. Furthermore, emerging nanomedicine and herbal drug candidates were highlighted as potential future treatments for Mpox. The findings underscore the effectiveness of TCV in treating Mpox and highlight significant advancements in preventive treatments. The review also points to innovative approaches in vaccine technology and potential future therapies, including nanomedicine and herbal remedies, which may enhance Mpox management.

Design of linked-domain protein inhibitors of UBE2D as tools to study cellular ubiquitination.

Ubiquitin (Ub) is a post-translational modification that largely controls proteostasis through mechanisms spanning transcription, translation, and notably, protein degradation. Ub conjugation occurs through a hierarchical cascade of three enzyme classes (E1, E2, and E3s) involving >1000 proteins that regulate the ubiquitination of proteins. The E2 Ub-conjugating enzymes are the midpoint, yet their cellular roles remain under-characterized, partly due to a lack of inhibitors. For example, the cellular roles of the promiscuous E2 UBE2D/UBCH5 are not well described. Here, we develop a highly selective, multivalent, engineered protein inhibitor for the UBE2D family that simultaneously targets the RING- and backside-binding sites. In HeLa cells, these inhibitors phenocopy knockdown of UBE2D by reducing the IC50 to cisplatin and whole-cell proteomics reveal an increased abundance of ~20% of the identified proteins, consistent with reduced Ub degradation and proteotoxic stress. These precision tools will enable new studies probing UBE2D's central role in proteome management.

Targeting Death Receptor 5 (DR5) for the imaging and treatment of primary bone and soft tissue tumors: an update of the literature.

Death Receptor 5 (DR5) is expressed on the surface of primary bone and soft tissue sarcoma cells, and its activation induces cell death primarily through apoptosis. The combination of DR5 agonists and commonly used chemotherapeutic agents, such as doxorubicin, can promote cell death. Currently, clinical trials are investigating the effectiveness of DR5 activation using new biological agents, such as bi-specific or tetravalent antibodies, in improving the survival of patients with relapsed or refractory cancers. Furthermore, investigations continue into the use of novel combination therapies to enhance DR5 response, for example, with inhibitor of apoptosis protein (IAP) antagonist agents [such as the second mitochondria-derived activator of caspase (SMAC) mimetics] and with immune checkpoint inhibitor anti-programmed death-ligand 1 (anti-PD-L1) or anti-programmed cell death-1 (anti-PD-1) antibodies. Other therapies include nanoparticle-mediated delivery of TRAIL plasmid DNA or TRAIL mRNA and stem cells as a vehicle for the targeted delivery of anti-cancer agents, such as TRAIL, to the tumor. Scoping review of the literature from November 2017 to March 2024, utilizing PubMed and Google Scholar. New agents under investigation include nanoTRAIL, anti-Kv10.1, multimeric IgM, and humanized tetravalent antibodies. Developments have been made to test novel agents, and imaging has been used to detect DR5 in preclinical models and patients. The models include 3D spheroids, genetically modified mouse models, a novel jaw osteosarcoma model, and patient-derived xenograft (PDX) animal models. There are currently two ongoing clinical trials focusing on the activation of DR5, namely, IGM-8444 and INBRX-109, which have progressed to phase 2. Further modifications of TRAIL delivery with fusion to single-chain variable fragments (scFv-TRAIL), directed against tumor-associated antigens (TAAs), and in the use of stem cells focus on targeted TRAIL delivery to cancer cells using bi-functional strategies. In vitro, in vivo, and clinical trials, as well as advances in imaging and theranostics, indicate that targeting DR5 remains a valid strategy in the treatment of some relapsed and refractory cancers.

Effect of allyl isothiocyanate on 4-HNE induced glucocorticoid resistance in COPD and the underlying mechanism

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition, and its clinical management primarily targets bronchodilation and anti-inflammatory therapy. However, these treatments often fail to directly address the progression of COPD, particularly its associated glucocorticoid (GC) resistance. This study elucidates the mechanisms underlying GC resistance in COPD and explores the therapeutic potential of allyl isothiocyanate (AITC) in modulating MRP1 transport. We assessed the levels of the oxidative stress product 4-HNE, HDAC2 protein, inflammatory markers, and pulmonary function indices using animal and cell models of GC-resistant COPD. The cascade effects of these factors were investigated through interventions involving AITC, protein inhibitors, and dexamethasone (DEX). Cigarette smoke-induced oxidative stress in COPD leads to the accumulation of the lipid peroxidation product 4-HNE, which impairs HDAC2 protein activity and diminishes GC-mediated anti-inflammatory sensitivity due to disrupted histone deacetylation. AITC regulates MRP1, facilitating the effective efflux of 4-HNE from cells, thereby reducing HDAC2 protein degradation and restoring dexamethasone sensitivity in COPD. These findings elucidate the mechanism of smoking-induced GC resistance in COPD and highlight MRP1 as a potential therapeutic target, as well as the enormous potential of AITC for combined GC therapy in COPD, promoting their clinical applications.

Clinical Assessment of Breast Cancer Resistance Protein (BCRP)-Mediated Drug-Drug Interactions of Sepiapterin with Curcumin and Rosuvastatin in Healthy Volunteers.

Sepiapterin, also known as PTC923 and CNSA-001, is a synthetic form of endogenous sepiapterin being developed as a novel oral treatment for phenylketonuria. Sepiapterin is a natural precursor of tetrahydrobiopterin (BH4) and, when orally administered, is converted to BH4 via the pterin salvage pathway. In vitro studies have demonstrated that both sepiapterin and BH4 are both substrates and inhibitors of the breast cancer resistance protein (BCRP) transporter. This phase I study investigated BCRP-mediated drug-drug interactions of sepiapterin as a victim and as a perpetrator. An open-label, fixed-sequence, four-period, crossover, single-dose study was conducted in adult male and female healthy volunteers (18-55 years of age). In a given treatment period, subjects received a single oral dose of sepiapterin (20 mg/kg), sepiapterin (20 mg/kg) plus curcumin (2 g), rosuvastatin (10 mg), or rosuvastatin (10 mg) plus sepiapterin (60 mg/kg). The pharmacokinetics of sepiapterin, its metabolite BH4, and rosuvastatin were studied, and geometric mean ratios of exposures in the presence and absence of the BCRP inhibitor curcumin or sepiapterin were estimated. The presence of the BCRP c.421C>A polymorphism was evaluated in all subjects. A total of 29 subjects were enrolled and included in the safety analysis. Among them, 26 subjects were included in the pharmacokinetic and drug-drug interaction analyses. Following oral administration20 mg/kg sepiapterin, sepiapterin was rapidly and extensively converted to BH4, and BH4 maximum observed concentration (415.0 ng/mL) was observed 4.95 h (time to maximum observed concentration) post-dose. Sepiapterin maximum observed concentration and area under the concentration-time curve from time 0 to time of the last quantifiable measurement or the last sample collection time (AUClast) were <1% of BH4 values. Coadministration of the BCRP inhibitor curcumin (2 g) increased BH4 maximum observed concentration, AUClast, and area under the concentration-time curve from time 0 extrapolated to infinity by 24%, 21%, and 20%, respectively. When sepiapterin was coadministered with the BCRP substrate rosuvastatin, there was no effect on the pharmacokinetics of rosuvastatin. BCRP c.421C/A carriers (n = 4) had higher plasma exposures of BH4 (1.39 × for AUClast) and rosuvastatin (1.61 × for AUClast) than c.421C/C carriers (n = 22). Greater increases in BH4 exposures (1.33 vs 1.18 for AUClast) were observed in c.421C/A carriers compared with c.421C/C carriers when sepiapterin was coadministered with curcumin. All treatments were well tolerated during the study. Oral coadministration of the BCRP inhibitor curcumin slightly increased the plasma exposure of sepiapterin and its metabolite BH4 in healthy volunteers. This modest increase was deemed not clinically meaningful. Sepiapterin did not alter the pharmacokinetics of the BCRP substrate rosuvastatin.

Structure–activity relationship study of small-molecule inhibitor of Atg12-Atg3 protein–protein interaction

Autophagy is a catabolic process that was described to play a critical role in advanced stages of cancer, wherein it maintains tumor cell homeostasis and growth by supplying nutrients. Autophagy is also described to support alternative cellular trafficking pathways, providing a non-canonical autophagy-dependent inflammatory cytokine secretion mechanism. Therefore, autophagy inhibitors have high potential in the treatment of cancer and acute inflammation. In our study, we identified compound 1 as an inhibitor of the ATG12-ATG3 protein–protein interaction. We focused on the systematic modification of the original hit 1, a casein kinase 2 (CK2) inhibitor, to find potent disruptors of ATG12-ATG3 protein–protein interaction. A systematic modification of the hit structure led us to a wide plethora of compounds that maintain its ATG12-ATG3 inhibitory activity, which could act as a viable starting point to design new compounds with diverse therapeutic applications.

Novel inhibitors of bromodomain and extra-terminal domain trigger cell death in breast cancer cell lines

Small molecule inhibitors targeting the bromodomain and extra-terminal domain (BET) family proteins have emerged as a promising class of anti-cancer drugs. Nevertheless, the clinical advancement of these agents has been significantly hampered by challenges related to their potency, oral bioavailability, or toxicity. In this study, virtual screening approaches were employed to discover novel inhibitors of the bromodomain-containing protein 4 (BRD4) by analyzing their comparable chemical structural features to established BRD4 inhibitors. Several of these compounds exhibited inhibitory effects on BRD4 activity ranging from 60 % to 70 % at 100 µM concentrations, while one compound also exhibited an 84 % inhibition of Sirtuin 2 (SIRT2) activity. Furthermore, a subset of structurally diverse compounds from the BRD4 inhibitors was selected to investigate their anti-cancer properties in both 2D and 3D cell cultures. These compounds exhibited varying effects on cell numbers depending on the specific cell line, and some of them induced cell cycle arrest in the G0/G1 phase in breast cancer (MDA-MB-231) cells. Moreover, all the compounds studied reduced the sizes of spheroids, and the most potent compound exhibited a 90 % decrease in growth at a concentration of 10 µM in T47D cells. These compounds hold potential as epigenetic regulators for future studies.

The BDNF-ERK/MAPK axis reduces phosphatase and actin regulator1, 2 and 3 (PHACTR1, 2 and 3) mRNA expressions in cortical neurons.

Actin rearrangement and phosphorylation-dephosphorylation in the nervous system contribute to plastic alteration of neuronal structure and function. Phosphatase and actin regulator (PHACTR) family members are actin- and protein phosphatase 1 (PP1)-binding proteins. Because some family members act as regulators of neuronal morphology, studying the regulatory mechanisms of PHACTR is valuable for understanding the basis of neuronal circuit formation. Although expression patterns of PHACTR family molecules (PHACTR1-4) vary across distinct brain areas, little is known about the extracellular ligands that influence their mRNA levels. In this study, we focused on an important neurotrophin, brain-derived neurotrophic factor (BDNF), and examined its effect on mRNA expression of PHACTR family member in cortical neurons. PHACTR1-3, but not PHACTR4, were affected by stimulation of primary cultured cortical neurons with BDNF; namely, sustained downregulation of their mRNA levels was observed. The observed downregulation was blocked by an inhibitor of the extracellular signal-regulated protein kinase/mitogen-activated protein kinase (ERK/MAPK) pathway, U0126, suggesting that ERK/MAPK plays an inhibitory role for gene induction of PHACTR1-3. These findings aid the elucidation of how BDNF regulates actin- and PP1-related neuronal functions.

Inhibitor of the non-structural protein 2 protease shows promising efficacy in mouse models of chikungunya

Chikungunya virus (CHIKV) is responsible for the most endemic alphavirus infections called Chikungunya. The endemicity of Chikungunya has increased over the past two decades, and it is a pathogen with pandemic potential. There is currently no approved direct-acting antiviral to treat the disease. As part of our antiviral drug discovery program focused on alphaviruses and the non-structural protein 2 protease, we discovered that J12 and J13 can inhibit CHIKV nsP2 protease and block the replication of CHIKV in cell cultures. Both compounds are metabolically stable to human liver microsomal and S9 enzymes. J13 has excellent oral bioavailability in pharmacokinetics studies in mice and ameliorated Chikungunya symptoms in preliminary efficacy studies in mice. J13 exhibited an excellent safety profile in in vitro safety pharmacology and off-target screening assays, making J13 and its analogs good candidates for drug development against Chikungunya.

Insight of the molecular mechanism of inhibitors located at different allosteric sites regulating the activity of wild type and mutant KRAS (G12)

As the important hub of many cellular signaling networks, KRAS (Kirsten rat sarcoma viral oncogene homologue) has been identified as a tumor biomarker. It is the frequently mutated oncogene in human cancers, and KRAS protein activation caused by mutations, such as G12D, has been found in many human tumors tissues. Although, there are two specific allosteric sites (AS1 and AS2) on the KRAS protein that can be used as the targets for inhibitor development, the difference of regulatory mechanisms between two individual allosteric sites still not be reported. Here, using molecular dynamics simulations combined with molecular mechanics generalized born surface area (MM/GBSA) analysis, we found that both of the inhibitors, located at AS1 and AS2, were able to reduce the binding free energy between wild type, mutant KRAS (G12/D/V/S/C) and GTP remarkably, however the effect of inhibitors on the binding free energy between wild type, mutant KRAS and GDP was limited. In addition, the degree of decrease of binding free energy between KRAS and GTP caused by inhibitors at AS2 was significantly greater than that caused by inhibitors at AS1. Further analysis revealed that both inhibitors at AS1 and AS2 were able to regulate the fluctuation of Switch Ⅰ and Switch Ⅱ to expand the pocket of the orthosteric site (GTP binding site), thereby reducing the binding of KRAS to GTP. Noteworthy there was significant differences in the regulatory preferences on Switch Ⅰ and Switch Ⅱ between two type inhibitor. The inhibitor at AS2 mainly regulated Switch Ⅱ to affect the pocket of the orthosteric site, while the inhibitor at AS1 mainly expand the pocket of the orthosteric site by regulating the fluctuation of Switch Ⅰ. Our study compared the differences between two type inhibitors in regulating the KRAS protein activity and revealed the advantages of the AS2 as the small molecule drug target, aiming to provide theoretical guidance for the research of novel KRAS protein inhibitors.

Novel Biomarkers in Early Prediction of Diabetic Nephropathy: A Systematic Review

Diabetes mellitus (DM) is a metabolic illness that is highly prevalent and intricate. Because of the high incidence of diabetic complications and disease mortality, the condition is one of the biggest medical and social issues in the world. Due to its rising prevalence, diabetes mellitus (DM), which raises blood glucose levels, is one of the world's health challenges and is anticipated to impact 495 million people. Diabetic kidney disease, or DKD, is a widespread ailment all over the world. It is the main cause of end-stage kidney disease (ESKD) and one of the most common consequences of diabetes mellitus (DM). Three essential elements play a role in its pathogenesis: the inflammatory, metabolic, and hemodynamic axis. Clinically, DKD is characterized by persistent albuminuria and a gradual reduction in glomerular filtration rate (GFR). These changes, however, are not unique to DKD, emphasizing the necessity to find new biomarkers originating from the disease's pathophysiology to support diagnosis, monitoring, treatment response, and prognosis. Cystatin C, also known as CysC, is a member of the cysteine protein inhibitor family and is a low-molecular-weight protein with 122 amino acids. The CST3 housekeeping gene, which is found on chromosome 20 (20pl1. 2, encodes it. Protein turnover, pro-protein processing, bone remodeling, antigen presentation, and apoptosis are among the physiological processes in which cysteine cathepsins are involved.

Comparative Efficacy of Colchicine and Intensive Low-density Lipoprotein Cholesterol Lowering in Patients with Atherosclerotic Diseases receiving Statins: A Network Meta-analysis of Randomized Controlled Trials.

Adding intensive low-density lipoprotein cholesterol (LDL-C)-lowering agents or colchicine to statin has been shown to result in additional cardiovascular benefits for patients with atherosclerotic cardiovascular diseases (ASCVD). We aimed to compare the efficacy and safety of these supplementary agents in patients with ASCVD receiving statin. We performed a systematic review and frequentist network meta-analysis of randomized controlled trials. The primary efficacy endpoint was the main adverse cardiovascular event (MACE), and the secondary efficacy endpoints were myocardial infarct, stroke, coronary revascularization, cardiovascular death, and all-cause mortality, respectively. The safety endpoints were treatment discontinuation and non-cardiovascular death. We obtained estimates for efficacy outcomes and safety endpoints and presented these estimates as risk ratio (RR) with 95% confidence intervals. We ranked the comparative efficacy and safety of all drugs with P-scores. Seventeen trials totaling 85,823 participants treated with colchicine (5926 participants), intensive LDL-C lowering (37,854 participants) via proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, Niemann-Pick C1-like 1 protein (NPC1L1) inhibitor or ATP citrate lyase (ACL) inhibitor, or statin alone (42,043 participants) were included. Colchicine was associated with a greater reduction in the risk of MACE (RR 0.72, 0.69-0.91), stroke (RR 0.55, 0.33-0.92), and coronary revascularization (RR 0.73, 0.60-0.90) compared with NPC1L1 inhibitor, and it provided a larger reduction in the risk of MACE (RR 0.79, 0.69-0.91) compared to PCSK9 inhibitor. However, colchicine was associated with increased risk of non-cardiovascular death compared with NPC1L1 inhibitor (RR 1.48, 1.04-2.10) and PCSK9 inhibitor (RR 1.57, 1.08-2.27). Although no regimen prolonged survival, colchicine had worse performance on non-cardiovascular death and all-cause mortality. In patients with ASCVD receiving statin, colchicine seems to be more effective than intensive LDL-C-lowering therapy with PCSK9 inhibitor or NPC1L1 inhibitor for cardiovascular prevention. However, using colchicine as an alternative to intensive LDL-C-lowering therapy may need to be weighed against the cardiovascular benefits and the potential harms of higher non-cardiovascular death. PROSPERO Identifier: CRD42023441385.

Evaluation of 68Ga-FAPI PET/CT and 18F-FDG PET/CT for the diagnosis of recurrent colorectal cancers

ObjectiveThe present study aimed to compare the diagnostic value of gallium-68-labeled fibroblast activation protein inhibitor positron emission tomography/computed tomography (68Ga-FAPI PET/CT) and fluorine-18-labeled fluorodeoxyglucose PET/CT (18F-FDG PET/CT) for detecting recurrent colorectal cancers (CRCs). Materials and MethodsFifty-six patients (age: 18–80 years, 31 men and 25 women) with suspected recurrent CRC were enrolled and underwent 18F-FDG PET/CT and 68Ga-FAPI PET/CT sequentially within 1 week. The maximum standard uptake value (SUVmax), tumor-to-background ratio (TBR), and diagnostic accuracy were estimated and compared between the two modalities by using Student’s t-test. The Wilcoxon signed-rank test was used to compare peritoneal carcinoma index (PCI) scores between the two imaging modalities. Results68Ga-FAPI PET/CT showed higher sensitivity for detecting recurrence (93 % vs. 79 %); lymph node metastasis (89 % vs. 78 %), particularly peritoneal lymph node metastasis (92 % vs. 63 %); and metastatic implantation on the intestinal wall (100 % vs. 25 %) compared to 18F-FDG PET/CT. However, 68Ga-FAPI PET/CT showed lower sensitivity for detecting bone metastasis (67 % vs. 100 %). The mean SUVmax values of peritoneal metastases and metastatic implantation on the intestinal wall were 4.28 ± 2.70 and 7.58 ± 1.66 for 18F-FDG PET/CT and 5.66 ± 1.97 and 6.70 ± 0.25 for 68Ga-FAPI PET/CT, respectively. Furthermore, 68Ga-FAPI PET/CT showed significantly higher TBR for peritoneal metastatic lesions (4.22 ± 1.47 vs. 1.41 ± 0.89, p < 0.0001) and metastatic implantation on the intestinal wall (5.63 ± 1.24 vs. 2.20 ± 0.5, p = 0.02) compared to 18F-FDG PET/CT. For the same patient, 68Ga-FAPI PET/CT yielded a more accurate PCI score and a greater area under the curve value for the receiver operating characteristic curve (p < 0.01) than 18F-FDG PET/CT. Conclusion68Ga-FAPI PET/CT was superior to 18F-FDG PET/CT for detecting recurrence and peritoneal metastases. Hence, we propose the combination of these two modalities for better clinical diagnosis and management of patients with CRC.

Is There a Role for FAPI PET in Urological Cancers?

This work aims to investigate the utility of positron emission tomography/computed tomography (PET/CT) with fibroblast activation protein inhibitors (FAPI) in urological neoplasms, including prostate cancer, urothelial carcinoma, and renal cell carcinoma. Although the available data are very preliminary, FAPI PET showed potential for detecting primary prostate cancer with low prostate-specific membrane antigen expression, while prostate-specific membrane antigen PET/CT outperformed FAPI PET/CT in detecting biochemical recurrence. In urothelial carcinoma, FAPI PET/CT demonstrated increased detection rates compared with deoxy-2-[18F]fluoro-D-glucose PET/CT, in particular in small lymph node metastases, whose identification is still an unmet clinical need. Limited data are available for renal cell carcinoma. In conclusion, FAPI PET emerges as a promising imaging modality for urological neoplasms, in particular bladder cancer. Further research is warranted to establish its role in guiding therapeutic decisions and as a potential novel theranostic agent.

High throughput screening for SARS-CoV-2 helicase inhibitors

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for nearly 7 million deaths worldwide since its outbreak in late 2019. Even with the rapid development and production of vaccines and intensive research, there is still a huge need for specific anti-viral drugs that address the rapidly arising new variants. To address this concern, the National Institute of Allergy and Infectious Diseases (NIAID) established nine Antiviral Drug Discovery (AViDD) Centers, tasked with exploring approaches to target pathogens with pandemic potential, including SARS-CoV-2. In this study, we sought inhibitors of SARS-CoV2 non-structural protein 13 (nsP13) as potential antivirals, first developing a HTS-compatible assay to measure SARS-CoV2 nsP13 helicase activity. Here we present our effort in implementing the assay in a 1,536 well-plate format and in identifying nsP13 inhibitor hit compounds from a ∼650,000 compound library. The primary screen was robust (average Z’ = 0.86 ± 0.05) and resulted in 7,009 primary hits. 1,763 of these compounds upon repeated retests were further confirmed, showing consistent inhibition. Following in-silico analysis, an additional orthogonal assay and titration assays, we identified 674 compounds with IC50 <10 μM. We confirmed activity of independent compound batches from de novo powders while also incorporating multiple counterscreen assays. Our study highlights the potential of this assay for use on HTS platforms to discover novel compounds inhibiting SARS-CoV2 nsP13, which merit further development as an effective SARS-CoV2 antiviral.

Extracellular Vesicle (EV) Survivin for Cancer Diagnostics and Therapeutics: A Review.

Survivin, an important inhibitor of apoptosis protein, contributes to cancer cells' resistance to apoptosis, proliferation, and survival. It is a promising biomarker and therapeutic target due to being highly expressed in cancer cells relative to normal cells and universally expressed in almost all cancer types. Cancer cells release survivin to the tumour microenvironment (TME) not only as a free protein but also encapsulated in extracellular vesicles (EVs), especially small EVs (sEVs). The release of encapsulated survivin from cancer cells can be taken up by neighbouring cells, eliciting pathological responses such as tumorigenesis and metastasis. Consequently, EV survivin holds potential as a diagnostic, prognostic, and therapeutic biomarker for several types of cancer, including breast cancer, prostate cancer, pancreatic cancer, and glioblastoma. EV survivin expression is significantly elevated in cancer patients and correlates with unfavourable clinicopathologic parameters. Although no clinical studies have explored EV survivin as a therapeutic target, future research should explore survivin-based therapies in combination with EV-targeting therapies to effectively disrupt its roles in tumorigenesis and metastasis.