Activation Of Intrinsic Pathway Research Articles

Lupus anticoagulant testing for patients on direct oral anticoagulants

Abstract As use of direct factor Xa inhibitor (direct oral anticoagulant; DOAC) therapy increases, a modified lupus anticoagulant (LAC) testing method was studied to remove interfering DOACs, allowing clinicians to evaluate patients for antiphospholipid syndrome (APS) without altering anticoagulation treatment. We evaluated the use of DOAC-StopTM on our LAC testing panel with two assays: dilute Russell viper venom time (dRVVT), a factor X activator, and Silica Clotting Time (SCT), an intrinsic coagulation pathway activator. The plasma specimens were pretreated with DOAC-STOPTM beads by mixing on a rocking platform for 5 minutes and centrifugation at 5000 rpm for 5 minutes. The treated plasma supernatant was used for each step of the assay including the screen, confirm (addition of phospholipid), 50:50 mix (addition of reagent plasma with coagulation factors) and confirm 50:50 mix. The total ratio (ratio between screen and confirm ratios relative to mean of normal ranges) was calculated and used per the package insert in the positive or negative interpretation of each LAC testing panel. The study included patients with one or more of the following characteristics identified during coagulation sign-out and chart review: no evidence of a LAC (NELAC), evidence of a LAC, and whether on apixaban or rivaroxaban therapy. The effectiveness of DOAC removal was characterized with an apixaban spiking experiment for NELAC and LAC patient specimens which showed no change in LAC testing panel interpretation before and after DOAC-STOPTM treatment. A second experiment with apixaban-spiked NELAC samples demonstrated removal of anti-factor Xa activity upon comparison of pre- and post-treatment with DOAC-STOPTM. Of 10 patients taking rivaroxaban, nine had positive dRVVT interpretations; eight of these specimens changed to negative interpretations after DOAC-STOPTM treatment. For SCT, two positive interpretations remained positive, while two of the remaining eight negatives became positive after treatment. Of nine patients taking apixaban, two had positive dRVVT interpretations, one of which became negative post-treatment. Of the seven negative interpretations, one became positive post-treatment. For SCT, three were positive pre-treatment and seven were negative with no change post-treatment. Providing a LAC testing option for patients on DOACs may be of benefit to patients and clinicians in APS assessment, eliminating the risk of suspending anticoagulation therapy. Our study shows DOAC-STOPTM effectively removes DOAC interference in the majority of patient specimens studied, though LAC testing and interpretation in the setting of a high-complexity patient population on DOAC therapy remains challenging with occasional false positives and false negatives.

Toll-like receptor 2 orchestrates a tumor suppressor response in non-small cell lung cancer.

Targeting early-stage lung cancer is vital to improve survival. However, the mechanisms and components of the early tumor suppressor response in lung cancer are not well understood. In this report, we study the role of Toll-like receptor 2 (TLR2), a regulator of oncogene-induced senescence, which is a key tumor suppressor response in premalignancy. Using human lung cancer samples and genetically engineered mouse models, we show that TLR2 is active early in lung tumorigenesis, where it correlates with improved survival and clinical regression. Mechanistically, TLR2 impairs early lung cancer progression via activation of cell intrinsic cell cycle arrest pathways and the proinflammatory senescence-associated secretory phenotype (SASP). The SASP regulates non-cell autonomous anti-tumor responses, such as immune surveillance of premalignant cells, and we observe impaired myeloid cell recruitment to lung tumors after Tlr2 loss. Last, we show that administration of a TLR2 agonist reduces lung tumor growth, highlighting TLR2 as a possible therapeutic target.

LACTB induces cancer cell death through the activation of the intrinsic caspase-independent pathway in breast cancer

BackgroundLACTB was recently identified as a mitochondrial tumour suppressor that negatively affects cancer cell proliferation by inducing cell death and/or differentiation, depending on the cell type and tissue. However, the detailed mechanism underlying the LACTB-induced cancer cell death is largely unknown.MethodsWe used cell-based, either in 2D or 3D conditions, and in vivo experiments to understand the LACTB mechanisms. In this regard, protein array followed by an enrichment analysis, cell proliferation assays using different compounds, western blot analysis, flow cytometry and immunofluorescence were performed. Differences between quantitative variables following normal distribution were valuated using Student t test for paired or no-paired samples according to the experiment. For in vivo experiments differences in tumour growth were analyzed by 2-way ANOVA.ResultsWe show, that LACTB expression leads to cell cycle arrest in G1 phase and increase of DNA oxidation that leads to activation of intrinsic caspase-independent cell death pathway. This is achieved by an increase of mitochondrial reactive oxygen species since early time points of LACTB induction.ConclusionOur work provides a deeper mechanistic insight into LACTB-mediated cancer-cell death and shows the dynamics of the cellular responses a particular tumor suppressive stimulus might evoke under different genetic landscapes.

Differential impact of milvexian, an investigational oral FXIa inhibitor vs apixaban and dabigatran on thrombin generation in human donor plasma in vitro

Abstract Introduction All approved anticoagulants including the direct oral anticoagulants have been associated with an increased risk of bleeding in a dose-dependent manner when used either as monotherapy and/or on top of antiplatelet drugs. Literature reports have suggested that the extrinsic pathway of coagulation is important for haemostasis while the intrinsic pathway of coagulation along with thrombin feedback activation of FXI are primarily responsible for pathological thrombus formation and propagation. Recent clinical trials with several FXI/FXIa inhibitors in development including milvexian (BMS-986177/ JNJ-70033093) have demonstrated robust antithrombic efficacy without any increase in bleeding compared with standard of care in the settings of total knee arthroplasty. Milvexian inhibits FXIa upstream in the intrinsic pathway of coagulation while approved anticoagulants including warfarin, heparin, bivalirudin, and DOACs inhibit FXa and/or thrombin, which are components of the final common pathway of coagulation that lies in the interface of the intrinsic and extrinsic pathways. Purpose To evaluate the impact of milvexian, apixaban and dabigatran on thrombin generation (TG) initiated by the intrinsic vs extrinsic pathway activators in human plasma in vitro. Methods Platelet-poor plasma prepared from citrated whole blood collected from consenting, healthy adult volunteers (n=6) was spiked with 0.1–10 μM milvexian, apixaban, or dabigatran. TG via the extrinsic pathway (5 pM tissue factor, PPP Reagent, Stago) and intrinsic pathway (1:100 dilution of STA®-PTT Automate) was measured using using the Thrombinoscope method (Stago) and included peak thrombin, lag time and the endogenous thrombin potential (ETP). Results All compounds tested demonstrated robust (>70%) to complete inhibition of the ETP initiated by the intrinsic pathway activator (STA®-PTT Automate reagent, Fig. 1A). Apixaban and dabigatran also completely inhibited ETP initiated by the extrinsic pathway activator (PPP Reagent, Fig. 1B). In contrast, milvexian only had a modest inhibition (<20%) of ETP when initiated by the extrinsic pathway activator. Conclusions By inhibiting the final common pathway of coagulation, apixaban and dabigatran inhibit TG initiated via both, intrinsic and extrinsic pathways, in a concentration-dependent manner. In contrast, by inhibiting FXIa upstream in the intrinsic pathway, milvexian predominantly inhibits TG initiated by the intrinsic pathway activator but only has a minimal impact on TG initiated by the extrinsic pathway that is deemed critical for haemostasis. These findings with milvexian are consistent with observations of TG in FXI immunodepleted plasma reported previously by our group (ISTH 2021). The potential haemostasis sparing effect of milvexian and perhaps of other FXI/FXIa inhibitors may explain in part the low rate of bleeding observed to date with this new class of experimental anticoagulant drugs in clinical development. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Janssen Research & Development

Antithrombotic potential of Lippia alba: A mechanistic approach

Ethnopharmacological relevanceLippia alba (Mill.) N.E.Br. ex Britton & P. Wilson is traditionally used in Brazil as an adjunct in the relief of mild anxiety, as an antispasmodic, and as an antidyspeptic. This medicinal species was included in the Phytotherapeutic Form of the Brazilian Pharmacopeia 2nd edition (2021) and has already been described as the most used medicinal plant in a study with patients from an Anticoagulation Clinic in Brazil. Meanwhile, no studies were found that support the safety of the use of L. alba in patients using anticoagulants, a drug with several safety limitations. Aim of the studyProvide scientific evidence to ensure the safety of the concomitant use of L. alba and warfarin and support the management of these patients by evaluating its in vitro anticoagulant effect and chemical composition. And, as a timely complementation, evaluate the potential of this medicinal species in the development of new antithrombotics. MethodsThe chemical profile of L. alba derivatives was analyzed by chromatographic methods such as Ultra-Performance Liquid Chromatography (UPLC) coupled with electrospray ionization mass spectrometry (ESI-MS), qualitative UPLC using Diode-Array Detection, and Thin Layer Chromatography. The anticoagulant activity was evaluated by the innovative Thrombin Generation Assay by Calibrated Automated Thrombogram method and using traditional coagulometric tests: prothrombin time, activated partial thromboplastin time, and plasma fibrinogen measurement. ResultsExtracts and fractions prolonged the coagulation time in all the tests and reduced thrombin formation in thrombin generation assay. Coagulation times with the addition of ethanloic extract (2.26 mg/mL) was 17.78s, 46.43s and 14.25s respectively in prothrombin time, activated partial thromboplastin time and fibrinogren plasma measurement. In thrombin generation test, this same extract showed ETP as 323 nM/min compared to control (815 nM/min) with high tissue factor and 582 nM/min compared to control (1147 nM/min) using low tissue factor. Presence of flavonoids, phenylpropanoids, and triterpenes were confirmed by chromatographic methods and 13 compounds were identified by UPLC-ESI-MS. Based on these results and on the scientific literature, it is possible to propose that phenylpropanoids and flavonoids are related to the anticoagulant activity observed. ConclusionThe results demonstrate the in vitro anticoagulant activity of L. alba, probably due to the activation of intrinsic and extrinsic pathways. It is concluded, then, that there is a potential for interaction, which needs to be further studied, between L. alba and warfarin. Also, this medicinal species shows a great potential for use in the development of new antithrombotics.

In Vitro and In Vivo Relevant Antineoplastic Activity of Platinum(II) Complexes toward Triple-Negative MDA-MB-231 Breast Cancer Cell Line.

Two platinum complexes [Pt(HL3)Cl]·H2O (3) and [Pt(HL4)Cl]·H2O (4) containing α- and β-naphthyl groups, respectively, were investigated in more detail in vitro and in vivo for antineoplastic activity. The cytotoxicity activity induced by these platinum(II) compounds against breast cancer (MDA-MB-231 and MCF-7), lung (A549), prostate (PC3), pancreas (BXPC-3), and normal peripheral blood mononuclear (PBMC) cells were evaluated by MTT assay. The cell viability MTT assay showed that complex (4) was more cytotoxic to all cancer cell lines tested and less cytotoxic against human PBMC. Therefore, complex (4) was selected to further investigate the mechanism of cytotoxic effects involved against MDA-MB-231 cell line (human triple-negative breast cancer). Sub-G1 analysis of the cell cycle showed that this complex induces cell death by apoptosis due to the cell loss of DNA content detected in flow cytometry. The cytotoxic effect induced by complex (4) was associated with the capability of the complex to induce mitochondrial membrane depolarization, as well as increase ROS levels and caspase activation, as a result of the activation of both extrinsic and intrinsic apoptosis pathways. Ultrastructural alterations were observed using scanning and transmission electron microscopy (SEM and TEM), such as membrane blebbing, filopodia reduction, empty mitochondrial matrix, and DNA fragmentation. Furthermore, complex (4) was tested in an MDA-MB-231 tumor nodule xenograft murine model and demonstrated a remarkable reduction in tumor size in BALB/c nude mice, when compared to the control animals.

Determination of Apoptotic Mechanism of Action of Tetrabromobisphenol A and Tetrabromobisphenol S in Human Peripheral Blood Mononuclear Cells: A Comparative Study.

Background: Tetrabromobisphenol A (TBBPA) is the most commonly used brominated flame retardant (BFR) in the industry. TBBPA has been determined in environmental samples, food, tap water, dust as well as outdoor and indoor air and in the human body. Studies have also shown the toxic potential of this substance. In search of a better and less toxic BFR, tetrabromobisphenol S (TBBPS) has been developed in order to replace TBBPA in the industry. There is a lack of data on the toxic effects of TBBPS, while no study has explored apoptotic mechanism of action of TBBPA and TBBPS in human leukocytes. Methods: The cells were separated from leucocyte-platelet buffy coat and were incubated with studied compounds in concentrations ranging from 0.01 to 50 µg/mL for 24 h. In order to explore the apoptotic mechanism of action of tested BFRs, phosphatidylserine externalization at cellular membrane (the number of apoptotic cells), cytosolic calcium ion and transmembrane mitochondrial potential levels, caspase-8, -9 and -3 activation, as well as PARP-1 cleavage, DNA fragmentation and chromatin condensation in PBMCs were determined. Results: TBBPA and TBBPS triggered apoptosis in human PBMCs as they changed all tested parameters in the incubated cells. It was also observed that the mitochondrial pathway was mainly involved in the apoptotic action of studied compounds. Conclusions: It was found that TBBPS, and more strongly TBBPA, triggered apoptosis in human PBMCs. Generally, the mitochondrial pathway was involved in the apoptotic action of tested compounds; nevertheless, TBBPS more strongly than TBBPA caused intrinsic pathway activation.

Apoptotic and Anti-metastatic Effects of Atractylodes lancea (Thunb.) DC. in a Hamster Model of Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a highly aggressive tumor with a greater risk of distant metastasis. The promising anti-CCA activity and safety profile of Atractylodes lancea (AL) have previously been reported in a series of in vitro, in vivo and clinical studies. The present study investigated the effect of AL extract on apoptosis and metastasis signaling pathways in the Opisthorchis viverrini/dimethylnitrosamine (OV/DMN)-induced CCA hamster model. Hamster liver tissues were obtained from the four groups (n = 5 per group), i.e., (i) 5-FU treated CCA (40 µg/mL); (ii) CCA; (iii) AL-treated CCA (5,000 mg/kg), and (iv) normal hamsters. Total RNA was isolated, and the expression levels of apoptosis-related and metastasis-related genes were determined by qRT-PCR analysis. The expression levels of p16, caspase-3, caspase-8, caspase-9, Apaf-1, p53 and Eef1a1 were downregulated, while that of the remaining genes were upregulated in CCA hamsters compared with normal hamsters. AL treatment increased the expression of p16, caspase-9, caspase-3, Apaf-1, p53 and E-cadherin and decreased the expression of cyclin D1, cdk4, Bax, Akt/PKB, Bcl-2, Mfge-8, Lass4, S100A6, TGF-β, Smad-2, Smad-3, Smad-4, MMP-9, and N-cadherin. The expression of Eef1a1 was unchanged. The anti-CCA activity of AL in OV/DMN-induced CCA hamsters could be due to the induction of cell cycle arrest at the G1 phase and activation of the apoptosis pathway, resulting in cancer cell death. The activation of the apoptosis pathway mainly involved the intrinsic pathway (activation of caspase-3 and caspase-9 through p53 and Mfge-8 modulation and downregulation of anti-apoptotic genes Akt and Bcl-2). In addition, AL could also inhibit the canonical TGF-β signaling pathway, MMP-9 and N-cadherin to suppress tumor metastasis.

Evaluation of anticancer activity of ferrocene based benzothiazole and β-ketooxothioacetal

Ferrocene-based compounds have recently gained widespread importance in cancer treatment becuase of their lower toxicity and cost-effective synthesis. However, ferrocene-based compounds do not exist in nature. Moreover, the synthesis of thianes containing ferrocene is quite rare. In the recent past, our group has reported iodine catalyzed synthesis of ferrocenated benzothiazole and β-ketooxothioacetal by the thermal reaction of ferrocenated β-chlorocinnamaldehyde with 2-aminothiophenol and 2-mercaptoethanol respectively.The molecular structure of both the compounds is quite interesting due to the presence of ferrocene which makes them highly important from an anticancer point of view. In this script, the synergistic effect of ferrocene and thiol has been observed in ferrocene functionalized thiols (Fenton reagents) for tumour growth suppression. The anticancer properties of both the compounds separately as well as in combination show a significant anticancer effect on cancer cell lines HCT116 (Colon), A549 (lung cancer), and MCF7 (Breast cancer). Both compounds and their combinations reflect cell death by generating ROS and depolarization of mitochondrial membrane potential. Gene expression profiling and protein expression studies of apoptosis-related genes (cleaved caspase 9, cleaved caspase 3, cleaved PARP and Bcl-2) were also evaluated. Results indicated that ferrocenated benzothiozole and β-ketooxothioacetal induced apoptosis through oxidative stress-mediated activation of intrinsic apoptosis pathway by generating intracellular ROS, loss of MMP, and alteration of expression of genes related to apoptosis. In addition, the anti-metastatic activity of benzothiozole and β-ketooxothioacetal was seen by wound healing assay showing anti-migratory properties. The properties like anti metastatic activity, cytotoxicity and showing synergistic effect when used in combination make benzothiozole and β-ketooxothioacetal potent platforms for the development of new anticancer agents. Benzothiazole and β-ketooxothioacetal can replace existing organometallic compounds with rare metals like platinum, due to their higher stability, lower cost, and lower toxicity.

The molecular mechanisms of vulpinic acid induced programmed cell death in melanoma.

Malignant melanoma is an aggressive skin tumor with a rapidly increasing incidence and there is not yet a successful treatment strategy. Vulpinic acid (VA) is derived from secondary metabolites from lichen species. In the current study, we, for the first time, investigated the anti-cancer effects of VA and the underlying mechanism VA induced programmed cell death in melanoma. The anti-cancer effects of VA on melanoma cells were evaluated by the xCELLigence system, flow cytometry, caspase-3 activity and RT-PCR analysis. Our results showed that VA had a strong anti-proliferative effect on A-375 melanoma cells without damaging human epidermal melanocyte cells. Additionally, VA promoted apoptotic cell death through G2/M arrest and the activation of both intrinsic and extrinsic apoptosis pathways according to the analysis of 88 genes associated with apoptosis by qRT-PCR. Our findings suggest that VA could become an alternative topical and transdermal treatment strategy in the treatment of maligned melanoma cancer. However, further investigations are needed to assess the underlying molecular mechanism of VA mediated apoptotic cell death in the treatment of melanoma.

Preparation and blood compatibility of polyethersulfone dialysis membrane modified by apixaban as coagulation factor Xa inhibitor.

Blood purification therapy is widely used in the treatment of critically ill patients. However, most dialysis membranes are prone to thrombosis. Activated coagulation factor X (FXa) functions at the intersection of intrinsic, extrinsic, and common coagulation pathways and plays a central role in thrombogenesis. To date, few dialysis membranes that directly inhibit FXa have been reported. We modified a polyethersulfone(PES) membrane using apixaban as an FXa inhibitor and investigated the performance of this membrane (AMPES). The contact angle of the modified membrane was reduced. PWF and retention rates of BSA were increased, demonstrating good hydrophilicity and dialysis performance. Albumin adsorption was reduced from 141.8±15.5 to 114.1±6.9μgcm-2. Reduced protein adsorption, especially targeted anti-FXa effect, inhibited the activation of intrinsic, extrinsic, and common coagulation pathways, as evidenced by significant prolongations of activated partial thromboplastin time, prothrombin time, and thrombin time by 145.04, 46.84 and 11.46s, respectively. Furthermore, we determined the FXa concentration of each group, and found that the modified membrane had better anticoagulant performance through the inhibition of FXa. Favorable antiplatelet activity was also demonstrated. Thromboelastogram was used to comprehensively evaluate the anticoagulant and antithrombotic activities of the modified membrane. The R value was increased by 43.1min, while the reduction in α angle was 42.5°. The coagulation comprehensive index reduction was 34.3. In addition, C3a and C5a were decreased by 15.3% and 30.4%, respectively. Furthermore, in vitro cytotoxicity and erythrocyte stability testing as well as in vivo murine experiments demonstrated the biosafety of the modified membrane. These results indicate that the AMPES dialysis membrane has an excellent potential for clinical applications.

Isolation and characterization of neurotoxic astrocytes derived from adult triple transgenic Alzheimer's disease mice

Alzheimer's disease has been considered mostly as a neuronal pathology, although increasing evidence suggests that glial cells might play a key role in the disease onset and progression. In this sense, astrocytes, with their central role in neuronal metabolism and function, are of great interest for increasing our understanding of the disease. Thus, exploring the morphological and functional changes suffered by astrocytes along the course of this disorder has great therapeutic and diagnostic potential.In this work we isolated and cultivated astrocytes from symptomatic 9-10-months-old adult 3xTg-AD mice, with the aim of characterizing their phenotype and exploring their pathogenic potential. These “old” astrocytes occurring in the 3xTg-AD mouse model of Alzheimer's Disease presented high proliferation rate and differential expression of astrocytic markers compared with controls. They were neurotoxic to primary neuronal cultures both, in neuronal-astrocyte co-cultures and when their conditioned media (ACM) was added into neuronal cultures. ACM caused neuronal GSK3β activation, changes in cytochrome c pattern, and increased caspase 3 activity, suggesting intrinsic apoptotic pathway activation. Exposure of neurons to ACM caused different subcellular responses. ACM application to the somato-dendritic domain in compartmentalised microfluidic chambers caused degeneration both locally in soma/dendrites and distally in axons. However, exposure of axons to ACM did not affect somato-dendritic nor axonal integrity.We propose that this newly described old 3xTg-AD neurotoxic astrocytic population can contribute towards the mechanistic understanding of the disease and shed light on new therapeutical opportunities.

Abstract 3008: Induction of necroptosis through caspase-independent mechanisms in MCF-7 breast cancer cells following HDAC inhibition

Abstract Cell proliferation and cell death are essential for maintaining homeostatic balance in eukaryotic organisms. Many diseases develop when cellular homeostasis is disturbed. Currently, several anti-cancer drugs are known to induce apoptosis through activation of intrinsic or extrinsic pathways. However, many types of cancer cells have acquired resistance due to quick adaptation to resist pro-apoptotic mechanisms. Therefore, simultaneous induction of other forms of cell deaths such as necroptosis, autophagy, etc., in addition to apoptosis, is becoming an attractive strategy for controlling tumor growth and metastasis. For this purpose, we have explored the role of XIAP in caspase-independent mechanisms of cell death during HDAC (Histone Deacetylase) inhibition. Our experiments with HDAC inhibitor SAHA (Suberoylanilide hydroxamic acid) have revealed that the anti-apoptotic biomarkers, including survivin and XIAP, exhibit important regulatory functions for inducing necroptosis in cancer cells. Interestingly, many of the signal adaptors of apoptosis and necroptosis are known to show dual functions during drug-induced cancer cell death. For example, the formation of the survivin-XIAP complex prevents XIAP from undergoing proteasomal degradation and polyubiquitination, thereby stabilizing XIAP in cancer cells. When the survivin level is increased, it is also known to stop the inhibition of XIAP by Smac. In addition, since XIAP can inhibit caspase -9 and the executioner caspases -3 and -7, the apoptosis mechanisms will be blocked, and cell proliferation will continue to promote cell survival and tumorigenesis. Our western blot data revealed that the caspase -9, -3, -7, and -8 levels were significantly downregulated in MCF-7 breast cancer cells following SAHA treatment. Furthermore, SAHA treatment also increased the levels of necroptosis inducers such as phospho-RIP3 and MLKL in MCF-7 cells. However, treatment of the same MCF-7 cells with other drugs such as RG-7388, an MDM2 inhibitor, was able to induce apoptosis through activation of caspases. Our current results show that MCF-7 cells may switch to the necroptosis pathway due to the inhibition of caspases and increased levels of survivin and XIAP. (This research was supported by the Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida). Citation Format: Umamaheswari Natarajan, Grace Waldron, Thiagarajan Venkatesan, Appu Rathinavelu. Induction of necroptosis through caspase-independent mechanisms in MCF-7 breast cancer cells following HDAC inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3008.

Sulforaphane inhibits histone deacetylase causing cell cycle arrest and apoptosis in oral squamous carcinoma cells

BackgroundBiologic compounds have recently generated interest in cancer chemoprevention. Sulforaphane (SFN), an isothiocyanate from cruciferous vegetables, has profound epigenetic actions. Since epigenetic aetiology is crucial for oral cancer, this study evaluated the role of SFN in oral cancer prevention. MethodsOral squamous cell carcinoma cells (UPCI-SCC-172) were treated with SFN in three concentrations: 10 μM, 20 μM and 30 μM for two time periods: 24 h and 48 h. MTT assay assessed cell proliferation. Histone deacetylase (HDAC) enzyme activity was colorimetrically estimated in the nuclear extracts. Flow cytometry determined cell cycle stages, reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) changes. Extrinsic and intrinsic apoptotic pathways were evaluated from caspase enzyme assays. ResultsCell proliferation and HDAC activity (44% in 24 h and 40% in 48 h) were significantly inhibited (p < 0.01). For 10 μM concentration, G2/M cell cycle arrest was found with a reduction in G1 phase cell population at 24 h and 48 h. Concentrations of 20 μM and 30 μM SFN presented cells in apoptosis marked by increased sub G1 cells at 48 h. Concentrations of 10 μM and 20 μM SFN showed a 1.3 to 2.8-fold increase in ROS generation at 24 h and 48 h. The concentration of 30 μM SFN showed a drop in ROS production, denoting cells already in apoptosis. Fall in MMP was also dose- and time-dependent. Caspase enzyme assays (p < 0.001) demonstrated activation of both extrinsic and intrinsic apoptotic pathways. ConclusionInhibitory action of SFN on oral cancer cell proliferation and HDAC activity led to cell cycle arrest and apoptosis. These effects marked by increase in ROS, a decrease in MMP and activation of apoptotic pathways offer exciting therapeutic options.

Spatial transcriptomics unravels novel signaling patterns at the leading edge of oral squamous cell carcinoma.

e18043 Background: Head and neck cancer is the 6th most common cancer worldwide. Oral squamous cell carcinoma (OSCC) is the most prevalent head and neck cancer that is characterized by aggressive local invasion and metastasis. Despite the leading edge (invasive front) of the tumor being a driver of OSCC pathophysiology, its biology and clinical relevance have not been fully characterized. We used spatial transcriptomics to explore signaling patterns within the leading edge and tumor core. Methods: Fresh-frozen, surgically resected OSCC samples from three HPV-negative OSCC patients were profiled using the 10x Genomics Visium Spatial Gene Expression platform. Leading edge and tumor core regions were defined by pathologist annotations and expression of previously identified edge and core gene signatures from the literature. Spatial differential gene expression (DGE) analysis and pathway analysis was performed using the Seurat package and Ingenuity Pathway Analysis (IPA), respectively. Cell-cell interaction networks were reconstructed using the CellChat package. Results: The leading edge and tumor core displayed unique transcriptional and signaling profiles that were conserved across all three OSCC patient samples. DEG analysis revealed 31 genes enriched in the leading edge and 62 genes enriched in the tumor core with a log2FC &gt; 0.58 and adjusted p-value &lt; 0.01. The top genes upregulated in the leading edge were FN1, COL1A1, COL1A2, IFITM3, and SPARC. Top tumor-core genes included CRCT1, LCE3D, DEFB4A, SPRR2A, and CNFN. IPA analysis of upregulated DEGs in the leading edge and tumor core predicted the activation of wound healing and GP6 signaling pathways, and activation of intrinsic prothrombin activation and MSP-RON signaling pathways, respectively. Cell communication analysis revealed that the leading edge had higher intercellular signaling than the tumor core. Upregulated leading edge cell signaling modules included collagen, CD99, CSPG4, and non-canonical WNT pathways, which have been linked to tumor invasion, metastasis, and adhesion. COL1A1 and COL1A2 ligands and CD44 and SDC1 receptors were upregulated in leading edge signaling. The tumor core was enriched for ANGPTL and PERIOSTIN cell signaling modules. Conclusions: This is the first study to characterize the tumor core and leading edge of OSCC tumors using spatial transcriptomics. Further investigation of the therapeutic potential of identified signaling pathways may improve OSCC outcomes.

A near-infrared fluorescent probe was used to evaluate the role of histone deacetylase in pulmonary fibrosis cells and mice

Idiopathic pulmonary fibrosis (IPF) is a common and serious pulmonary fibrosis disease, the pathogenesis of IPF is closely related to a variety of biological small molecules and proteins, Histone deacetylases (HDACs) play an important role in inhibiting apoptosis and promoting pulmonary fibrosis. Here, we propose Cy-HDAC, (a HDACs fluorescent probe), which is selective and sensitive to HDACs and can be used to detect real-time fluctuations in HDACs activity in cells and mouse models. Our results suggest that HDAC inhibitors suberoylanilide hydroxamic acid (SAHA) treatment in the model group of pulmonary fibrosis leads to enhanced acetylation of histone H3, which allows increased transcription of some apoptosis-related proteins, promoting the activation of apoptotic protein Bak and mitochondria intrinsic apoptotic pathways, while the reduction of anti-apoptotic protein Bcl-xL promotes fibroblast apoptosis. In the bleomycin-induced pulmonary fibrosis mouse model, we found that pulmonary fibrosis severity was reduced in the SAHA-treated group, and SAHA combined with pirfenidone was superior to pirfenidone alone. Therefore, HDACs levels in IPF may provide a new detection possibility for IPF diagnosis, and HDACs may provide a novel alternative for the treatment of IPF.

Novel interaction of properdin and coagulation factor XI: Crosstalk between complement and coagulation

BackgroundEvidence of crosstalk between the complement and coagulation cascades exists, and dysregulation of either pathway can lead to serious thromboinflammatory events. Both the intrinsic pathway of coagulation and the alternative pathway of complement interact with anionic surfaces, such as glycosaminoglycans. Hitherto, there is no evidence for a direct interaction of properdin (factor P [FP]), the only known positive regulator of complement, with coagulation factor XI (FXI) or activated FXI (FXIa). ObjectivesThe aim was to investigate crosstalk between FP and the intrinsic pathway and the potential downstream consequences. MethodsChromogenic assays were established to characterize autoactivation of FXI in the presence of dextran sulfate (DXS), enzyme kinetics of FXIa, and the downstream effects of FP on intrinsic pathway activity. Substrate specificity changes were investigated using SDS‐PAGE and liquid chromatography–mass spectrometry (LC‐MS). Surface plasmon resonance (SPR) was used to determine direct binding between FP and FXIa. Results/ConclusionsWe identified a novel interaction of FP with FXIa resulting in functional consequences. FP reduces activity of autoactivated FXIa toward S‐2288. FXIa can cleave FP in the presence of DXS, demonstrated using SDS‐PAGE, and confirmed by LC‐MS. FXIa can cleave factor IX (FIX) and FP in the presence of DXS, determined by SDS‐PAGE. DXS alone modulates FXIa activity, and this effect is further modulated by FP. We demonstrate that FXI and FXIa bind to FP with high affinity. Furthermore, FX activation downstream of FXIa cleavage of FIX is modulated by FP. These findings suggest a novel intercommunication between complement and coagulation pathways.

Targeting Myc-driven stress vulnerability in mutant KRAS colorectal cancer

Mutant KRAS is a key driver in colorectal cancer (CRC) and promotes Myc translation and Myc-dependent stress adaptation and proliferation. Here, we report that the combination of two FDA-approved drugs Bortezomib and Everolimus (RAD001) (BR) is highly efficacious against mutant KRAS CRC cells. Mechanistically, the combination, not single agent, rapidly depletes Myc protein, not mRNA, and leads to GCN2- and p-eIF2α-dependent cell death through the activation of extrinsic and intrinsic apoptotic pathways. Cell death is selectively induced in mutant KRAS CRC cells with elevated basal Myc and p-eIF2α and is characterized by CHOP induction and transcriptional signatures in proteotoxicity, oxidative stress, metabolic inhibition, and immune activation. BR-induced p-GCN2/p-eIF2α elevation and cell death are strongly attenuated by MYC knockdown and enhanced by MYC overexpression. The BR combination is efficacious against mutant KRAS patient derived organoids (PDO) and xenografts (PDX) by inducing p-eIF2α/CHOP and cell death. Interestingly, an elevated four-gene (DDIT3, GADD45B, CRYBA4 and HSPA1L) stress signature is linked to shortened overall survival in CRC patients. These data support that Myc-dependent stress adaptation drives the progression of mutant KRAS CRC and serves as a therapeutic vulnerability, which can be targeted using dual translational inhibitors.

The targeted SMAC mimetic SW IV-134 augments platinum-based chemotherapy in pre-clinical models of ovarian cancer

BackgroundOvarian cancer is initially responsive to frontline chemotherapy. Unfortunately, it often recurs and becomes resistant to available therapies and the survival rate for advanced and recurrent ovarian cancer is unacceptably low. We thus hypothesized that it would be possible to achieve more durable treatment responses by combining cisplatin chemotherapy with SW IV-134, a cancer-targeted peptide mimetic and inducer of cell death. SW IV-134 is a recently developed small molecule conjugate linking a sigma-2 ligand with a peptide analog (mimetic) of the intrinsic death pathway activator SMAC (second-mitochondria activator of caspases). The sigma-2 receptor is overexpressed in ovarian cancer and the sigma-2 ligand portion of the conjugate facilitates cancer selectivity. The effector portion of the conjugate is expected to synergize with cisplatin chemotherapy and the cancer selectivity is expected to reduce putative off-target toxicities.MethodsOvarian cancer cell lines were treated with cisplatin alone, SW IV-134 alone and a combination of the two drugs. Treatment efficacy was determined using luminescent cell viability assays. Caspase-3/7, − 8 and − 9 activities were measured as complementary indicators of death pathway activation. Syngeneic mouse models and patient-derived xenograft (PDX) models of human ovarian cancer were studied for response to SW IV-134 and cisplatin monotherapy as well as combination therapy. Efficacy of the therapy was measured by tumor growth rate and survival as the primary readouts. Potential drug related toxicities were assessed at necropsy.ResultsThe combination treatment was consistently superior in multiple cell lines when compared to the single agents in vitro. The expected mechanism of tumor cell death, such as caspase activation, was confirmed using luminescent and flow cytometry-based assay systems. Combination therapy proved to be superior in both syngeneic and PDX-based murine models of ovarian cancer. Most notably, combination therapy resulted in a complete resolution of established tumors in all study animals in a patient-derived xenograft model of ovarian cancer.ConclusionsThe addition of SW IV-134 in combination with cisplatin chemotherapy represents a promising treatment option that warrants further pre-clinical development and evaluation as a therapy for women with advanced ovarian cancer.

Contact and intrinsic coagulation pathways are activated and associated with adverse clinical outcomes in COVID-19

AbstractCoagulation activation is a prominent feature of severe acute respiratory syndrome coronavirus 2 (COVID-19) infection. Activation of the contact system and intrinsic pathway has increasingly been implicated in the prothrombotic state observed in both sterile and infectious inflammatory conditions. We therefore sought to assess activation of the contact system and intrinsic pathway in individuals with COVID-19 infection. Baseline plasma levels of protease:serpin complexes indicative of activation of the contact and intrinsic pathways were measured in samples from inpatients with COVID-19 and healthy individuals. Cleaved kininogen, a surrogate for bradykinin release, was measured by enzyme-linked immunosorbent assay, and extrinsic pathway activation was assessed by microvesicle tissue factor–mediated factor Xa (FXa; MVTF) generation. Samples were collected within 24 hours of COVID-19 diagnosis. Thirty patients with COVID-19 and 30 age- and sex-matched controls were enrolled. Contact system and intrinsic pathway activation in COVID-19 was demonstrated by increased plasma levels of FXIIa:C1 esterase inhibitor (C1), kallikrein:C1, FXIa:C1, FXIa:α1-antitrypsin, and FIXa:antithrombin (AT). MVTF levels were also increased in patients with COVID-19. Because FIXa:AT levels were associated with both contact/intrinsic pathway complexes and MVTF, activation of FIX likely occurs through both contact/intrinsic and extrinsic pathways. Among the protease:serpin complexes measured, FIXa:AT complexes were uniquely associated with clinical indices of disease severity, specifically total length of hospitalization, length of intensive care unit stay, and extent of lung computed tomography changes. We conclude that the contact/intrinsic pathway may contribute to the pathogenesis of the prothrombotic state in COVID-19. Larger prospective studies are required to confirm whether FIXa:AT complexes are a clinically useful biomarker of adverse clinical outcomes.