CAMSAP3-mediated regulation of HMGB1 acetylation and subcellular localization in lung cancer cells: Implications for cell death modulation

BACKGROUND

Deregulation of cell death is a common characteristic of cancer, and resistance to this process often occurs in lung cancer. Understanding the molecular mechanisms underlying an aberrant cell death is important. Recent studies have emphasized the involvement of calmodulin-regulated spectrin-associated protein 3 (CAMSAP3) in lung cancer aggressiveness, its influence on cell death regulation remains largely unexplored.

METHODS

CAMSAP3 was knockout in lung cancer cells using CRISPR-Cas9 system. Cell death and autophagy were evaluated using MTT and autophagic detection assays. Protein interactions were performed by proteomic analysis and immunoprecipitation. Protein expressions and their cytoplasmic localization were analyzed through immunoblotting and immunofluorescence techniques.

RESULTS

This study reveals a significant correlation between low CAMSAP3 expression and poor overall survival rates in lung cancer patients. Proteomic analysis identified high mobility group box 1 (HMGB1) as a candidate interacting protein involved in the regulation of cell death. Treatment with trichostatin A (TSA), an inhibitor of histone deacetylases (HDACs) resulted in increased HMGB1 acetylation and its translocation to the cytoplasm and secretion, thereby inducing autophagic cell death. However, this process was diminished in CAMSAP3 knockout lung cancer cells. Mechanistically, immunoprecipitation indicated an interaction between CAMSAP3 and HMGB1, particularly with its acetylated form, in which this complex was elevated in the presence of TSA.

CONCLUSIONS

CAMSAP3 is prerequisite for TSA-mediated autophagic cell death by interacting with cytoplasmic acetylated HMGB1 and enhancing its release.

SIGNIFICANT

This finding provides molecular insights into the role of CAMSAP3 in regulating cell death, highlighting its potential as a therapeutic target for lung cancer treatment.

Pharmacological Ascorbate Elicits Anti-Cancer Activities against Non-Small Cell Lung Cancer through Hydrogen-Peroxide-Induced-DNA-Damage

Non-small cell lung cancer (NSCLC) poses a significant global health burden with unsatisfactory survival rates, despite advancements in diagnostic and therapeutic modalities. Novel therapeutic approaches are urgently required to improve patient outcomes. Pharmacological ascorbate (P-AscH-; ascorbate at millimolar concentration in plasma) emerged as a potential candidate for cancer therapy for recent decades. In this present study, we explore the anti-cancer effects of P-AscH- on NSCLC and elucidate its underlying mechanisms. P-AscH- treatment induces formation of cellular oxidative distress; disrupts cellular bioenergetics; and leads to induction of apoptotic cell death and ultimately reduction in clonogenic survival. Remarkably, DNA and DNA damage response machineries are identified as vulnerable targets for P-AscH- in NSCLC therapy. Treatments with P-AscH- increase the formation of DNA damage and replication stress markers while inducing mislocalization of DNA repair machineries. The cytotoxic and genotoxic effects of P-AscH- on NSCLC were reversed by co-treatment with catalase, highlighting the roles of extracellular hydrogen peroxide in anti-cancer activities of P-AscH-. The data from this current research advance our understanding of P-AscH- in cancer treatment and support its potential clinical use as a therapeutic option for NSCLC therapy.

Ca-EDTA restores the activity of ceftazidime-avibactam or aztreonam against carbapenemase-producing Klebsiellapneumoniae infections

Developing an effective therapy to overcome carbapenemase-positive Klebsiella pneumoniae (CPKp) is an important therapeutic challenge that must be addressed urgently. Here, we explored a Ca-EDTA combination with aztreonam or ceftazidime-avibactam in vitro and in vivo against diverse CPKp clinical isolates. The synergy testing of this study demonstrated that novel aztreonam-Ca-EDTA or ceftazidime-avibactam-Ca-EDTA combination was significantly effective in eliminating planktonic and mature biofilms in vitro, as well as eradicating CPKp infections in vivo. Both combinations revealed significant therapeutic efficacies in reducing bacterial load in internal organs and protecting treated mice from mortality. Conclusively, this is the first in vitro and in vivo study to demonstrate that novel aztreonam-Ca-EDTA or ceftazidime-avibactam-Ca-EDTA combinations provide favorable efficacy and safety for successful eradication of carbapenemase-producing Klebsiella pneumoniae planktonic and biofilm infections.

mTORC2 interactome and localization determine aggressiveness of high-grade glioma cells through association with gelsolin

mTOR complex 2 (mTORC2) has been implicated as a key regulator of glioblastoma cell migration. However, the roles of mTORC2 in the migrational control process have not been entirely elucidated. Here, we elaborate that active mTORC2 is crucial for GBM cell motility. Inhibition of mTORC2 impaired cell movement and negatively affected microfilament and microtubule functions. We also aimed to characterize important players involved in the regulation of cell migration and other mTORC2-mediated cellular processes in GBM cells. Therefore, we quantitatively characterized the alteration of the mTORC2 interactome under selective conditions using affinity purification-mass spectrometry in glioblastoma. We demonstrated that changes in cell migration ability specifically altered mTORC2-associated proteins. GSN was identified as one of the most dynamic proteins. The mTORC2-GSN linkage was mostly highlighted in high-grade glioma cells, connecting functional mTORC2 to multiple proteins responsible for directional cell movement in GBM. Loss of GSN disconnected mTORC2 from numerous cytoskeletal proteins and affected the membrane localization of mTORC2. In addition, we reported 86 stable mTORC2-interacting proteins involved in diverse molecular functions, predominantly cytoskeletal remodeling, in GBM. Our findings might help expand future opportunities for predicting the highly migratory phenotype of brain cancers in clinical investigations.

CAMSAP3 negatively regulates lung cancer cell invasion and angiogenesis through nucleolin/HIF-1α mRNA complex stabilization

AIMS

Cancer metastasis is a major cause of lung cancer-related mortality, so identification of related molecular mechanisms is of interest. Calmodulin-regulated spectrin-associated protein 3 (CAMSAP3) has been implicated in lung cancer malignancies; however, its role in metastatic processes, including invasion and angiogenesis, is largely unknown.

MAIN METHOD

The clinical relevance of CAMSAP3 expression in lung cancer was evaluated. The relevance of CAMSAP3 expression to in vitro cell invasion and angiogenesis was assessed in human lung cancer cells and endothelial cells, respectively. The molecular mechanism was identified by qRT-PCR, immunoprecipitation, mass spectrometry, and RNA immunoprecipitation. The in vivo metastatic and angiogenic activities of lung cancer cells were assessed.

KEY FINDINGS

Low CAMSAP3 expression was found in malignant lung tissues and strongly correlated with a poor prognosis in lung adenocarcinoma (LUAD). CAMSAP3-knockout NSCLC exhibited high invasive ability, and CAMSAP3 knockout induced HUVEC proliferation and tube formation; these effects were significantly attenuated by reintroduction of exogenous wild-type CAMSAP3. Mechanistically, in the absence of CAMSAP3, the expression of hypoxia-inducible factor-1α (HIF-1α) was upregulated, which increased the levels of downstream HIF-1α targets such as vascular endothelial growth factor A (VEGFA) and matrix metalloproteinases (MMPs) 2 and 9. Proteomic analysis revealed that nucleolin (NCL) bound to CAMSAP3 to regulate HIF-1α mRNA stabilization. In addition, CAMSAP3-knockout lung cancer cells displayed highly aggressive behavior in metastasis and angiogenesis in vivo.

SIGNIFICANCE

This study reveals that CAMSAP3 plays a negative regulatory role in lung cancer cell metastatic behavior both in vitro and in vivo through NCL/HIF-1α mRNA complex stabilization.

Inhibition of histone deacetylase 6 destabilizes ERK phosphorylation and suppresses cancer proliferation via modulation of the tubulin acetylation-GRP78 interaction

BACKGROUND

The leading cause of cancer-related mortality worldwide is lung cancer, and its clinical outcome and prognosis are still unsatisfactory. The understanding of potential molecular targets is necessary for clinical implications in precision diagnostic and/or therapeutic purposes. Histone deacetylase 6 (HDAC6), a major deacetylase enzyme, is a promising target for cancer therapy; however, the molecular mechanism regulating cancer pathogenesis is largely unknown.

METHODS

The clinical relevance of HDAC6 expression levels and their correlation with the overall survival rate were analyzed based on the TCGA and GEO databases. HDAC6 expression in clinical samples obtained from lung cancer tissues and patient-derived primary lung cancer cells was evaluated using qRT-PCR and Western blot analysis. The potential regulatory mechanism of HDAC6 was identified by proteomic analysis and validated by immunoblotting, immunofluorescence, microtubule sedimentation, and immunoprecipitation-mass spectrometry (IP-MS) assays using a specific inhibitor of HDAC6, trichostatin A (TSA) and RNA interference to HDAC6 (siHDAC6). Lung cancer cell growth was assessed by an in vitro 2-dimensional (2D) cell proliferation assay and 3D tumor spheroid formation using patient-derived lung cancer cells.

RESULTS

HDAC6 was upregulated in lung cancer specimens and significantly correlated with poor prognosis. Inhibition of HDAC6 by TSA and siHDAC6 caused downregulation of phosphorylated extracellular signal-regulated kinase (p-ERK), which was dependent on the tubulin acetylation status. Tubulin acetylation induced by TSA and siHDAC6 mediated the dissociation of p-ERK on microtubules, causing p-ERK destabilization. The proteomic analysis demonstrated that the molecular chaperone glucose-regulated protein 78 (GRP78) was an important scaffolder required for p-ERK localization on microtubules, and this phenomenon was significantly inhibited by either TSA, siHDAC6, or siGRP78. In addition, suppression of HDAC6 strongly attenuated an in vitro 2D lung cancer cell growth and an in vitro 3D patient derived-lung cancer spheroid growth.

CONCLUSIONS

HDAC6 inhibition led to upregulate tubulin acetylation, causing GRP78-p-ERK dissociation from microtubules. As a result, p-ERK levels were decreased, and lung cancer cell growth was subsequently suppressed. This study reveals the intriguing role and molecular mechanism of HDAC6 as a tumor promoter, and its inhibition represents a promising approach for anticancer therapy.

cGAS deficiency enhances inflammasome activation in macrophages and inflammatory pathology in pristane-induced lupus

Introduction

Type I interferon (IFN) plays a vital role in the pathogenesis of systemic lupus erythematosus. Cyclic GMP AMP synthase (cGAS) is a cytosolic DNA sensor that recognizes dsDNA and creates cGAMP to activate STING-mediated type I IFN production. The activation of STING induces lupus disease in Fcgr2b deficient mice through the differentiation of dendritic cells. In contrast, Cgas-deficient mice could be generated more autoantibody production and proteinuria in pristane-induced lupus (PIL). These data suggested that the other dsDNA sensors could be involved in lupus development mechanisms.

Methods

This study aimed to identify the cGAS-mediated mechanisms contributing to lupus pathogenesis in PIL. The Cgas-deficient and WT mice were induced lupus disease with pristane and subsequently analyzed autoantibody, histopathology, and immunophenotypes. The lung tissues were analyzed with the expression profiles by RT-PCR and western blot. The bone marrow-derived macrophages were stimulated with inflammasome activators and observed pyroptosis.

Results

The Cgas-/- mice developed more severe pulmonary hemorrhage and autoantibody production than WT mice. The activated dendritic cells, IFN-g-, and IL-17a-producing T helper cells, and infiltrated macrophages in the lung were detected in Cgas-/- mice higher than in WT mice. We observed an increase in expression of Aim2, Casp11, and Ifi16 in the lung and serum IL-1a but IL-1b in pristane-injected Cgas-/- mice. The rise of Caspase-11 in the lung of pristane-injected Cgas-/- mice suggested noncanonical inflammasome activation. The activation of AIM2 and NLRP3 inflammasomes in bone marrow-derived macrophages (BMDMs) enhanced the number of dead cells in Cgas-/- mice compared with WT mice. Activation of the inflammasome significantly induced pyroptosis in Cgas-/- BMDMs. The dsDNA level, but not mitochondrial DNA, increased dramatically in pristane-injected Cgas-/- mice suggesting the dsDNA could be a ligand activating inflammasomes. The cGAS agonist-induced BMDM activation in the Cgas-/- mice indicated that the activation of DNA sensors other than cGAS enhanced activated macrophages.

Conclusion

These findings suggested that cGAS hampers the unusual noncanonical inflammasome activation through other DNA sensors.

Phosphoproteomic Analysis Defines BABAM1 as mTORC2 Downstream Effector Promoting DNA Damage Response in Glioblastoma Cells

Glioblastoma (GBM) is a devastating primary brain cancer with a poor prognosis. GBM is associated with an abnormal mechanistic target of rapamycin (mTOR) signaling pathway, consisting of two distinct kinase complexes: mTORC1 and mTORC2. The complexes play critical roles in cell proliferation, survival, migration, metabolism, and DNA damage response. This study investigated the aberrant mTORC2 signaling pathway in GBM cells by performing quantitative phosphoproteomic analysis of U87MG cells under different drug treatment conditions. Interestingly, a functional analysis of phosphoproteome revealed that mTORC2 inhibition might be involved in double-strand break (DSB) repair. We further characterized the relationship between mTORC2 and BRISC and BRCA1-A complex member 1 (BABAM1). We demonstrated that pBABAM1 at Ser29 is regulated by mTORC2 to initiate DNA damage response, contributing to DNA repair and cancer cell survival. Accordingly, the inactivation of mTORC2 significantly ablated pBABAM1 (Ser29), reduced DNA repair activities in the nucleus, and promoted apoptosis of the cancer cells. Furthermore, we also recognized that histone H2AX phosphorylation at Ser139 (γH2AX) could be controlled by mTORC2 to repair the DNA. These results provided a better understanding of the mTORC2 function in oncogenic DNA damage response and might lead to specific mTORC2 treatments for brain cancer patients in the future.

Helicene-Hydrazide Encapsulated Ethyl Cellulose as a Potential Fluorescence Sensor for Highly Specific Detection of Nonanal in Aqueous Solutions and a Proof-of-Concept Clinical Study in Lung Fluid

Over the past years, lung cancer has been one of the vital cancer-related mortalities worldwide and has inevitably exhibited the highest death rate with the subsequent need for facile and convenient diagnosis approaches to identify the severity of cancer. Previous research has reported long-chain aldehyde compounds such as hexanal, heptanal, octanal, and nonanal as potential biomarkers of lung cancer. Herein, the helicene dye-encapsulated ethyl cellulose (EC@dye-NH) nanosensors have been applied for the potentially sensitive and specific detection of long-chain aldehydes in aqueous media. The sensors contain the intrinsic hydrazide group of dye-NH, which is capable of reacting an aldehyde group via imine formation and the EC backbone. This offers the synergistic forces of hydrophobic interactions with alkyl long-chain aldehydes, which could induce self-assembly encapsulation of EC@dye-NH nanosensors and strong fluorescence responses. The addition of long-chain aldehyde would induce the complete micellar-like nanoparticle formation within 15 min in acetate buffer pH 5.0. The limit of detection (LOD) values of EC@dye-NH nanosensors toward heptanal, octanal, and nonanal were 40, 100, and 10 μM, respectively, without interference from the lung fluid matrices and short-chain aldehydes. For practical applicability, this sensing platform was developed for quantification of the long-chain aldehydes in lung fluid samples with 98-101% recoveries. This EC@dye-NH nanosensor was applied to quantify nonanal contents in lung fluid samples. The results of this method based on EC@dye-NH nanosensors were then validated using standard gas chromatography-mass spectrometry (GC-MS), which gave results consistent with the proposed method. With intracellular imaging application, the EC@dye-NH nanosensors demonstrated excellent intracellular uptake and strong green fluorescence emission upon introducing the nonanal into the lung cancer cells (A549). Thus, the developed nanosensing approach served as the potential fluorescent probes in medical and biological fields, especially for lung cancer disease diagnosis based on highly selective and sensitive detection of long-chain aldehydes.

IRF7-deficient MDCK cell based on CRISPR/Cas9 technology for enhancing influenza virus replication and improving vaccine production

The influenza virus is a cause of seasonal epidemic disease and enormous economic injury. The best way to control influenza outbreaks is through vaccination. The Madin-Darby canine kidney cell line (MDCK) is currently approved to manufacture influenza vaccines. However, the viral load from cell-based production is limited by host interferons (IFN). Interferon regulating factor 7 (IRF7) is a transcription factor for type-I IFN that plays an important role in regulating the anti-viral mechanism and eliminating viruses. We developed IRF7 knock-out MDCK cells (IRF7^-/ - MDCK) using CRISPR/Cas9 technology. The RNA expression levels of IRF7 in the IRF7^-/ - MDCK cells were reduced by 94.76% and 95.22% under the uninfected and infected conditions, respectively. Furthermore, the IRF7 protein level was also significantly lower in IRF7^-/ - MDCK cells for both uninfected (54.85% reduction) and viral infected conditions (32.27% reduction) compared to WT MDCK. The differential expression analysis of IFN-related genes demonstrated that the IRF7^-/ - MDCK cell had a lower interferon response than wildtype MDCK under the influenza-infected condition. Gene ontology revealed down-regulation of the defense response against virus and IFN-gamma production in IRF7^-/ - MDCK. The evaluation of influenza viral titers by RT-qPCR and hemagglutination assay (HA) revealed IRF7^-/ - MDCK cells had higher viral titers in cell supernatant, including A/pH1N1 (4 to 5-fold) and B/Yamagata (2-fold). Therefore, the IRF7^-/ - MDCK cells could be applied to cell-based influenza vaccine production with higher capacity and efficiency.

MicroRNA-223 Suppresses Human Hepatic Stellate Cell Activation Partly via Regulating the Actin Cytoskeleton and Alleviates Fibrosis in Organoid Models of Liver Injury

MicroRNAs (miRNAs) are small, non-coding RNAs that negatively regulate target mRNA expression, and altered expression of miRNAs is associated with liver pathological conditions. Recent studies in animal models have shown neutrophil/myeloid-specific microRNA-223 (miR-223) as a key regulator in the development of various liver diseases including fibrosis, where hepatic stellate cells (HSCs) are the key player in pathogenesis. However, the precise roles of miR-223 in human HSCs and its therapeutic potential to control fibrosis remain largely unexplored. Using primary human HSCs, we demonstrated that miR-223 suppressed the fibrogenic program and cellular proliferation while promoting features of quiescent HSCs including lipid re-accumulation and retinol storage. Furthermore, induction of miR-223 in HSCs decreased cellular motility and contraction. Mechanistically, miR-223 negatively regulated expression of smooth muscle α-actin (α-SMA) and thus reduced cytoskeletal activity, which is known to promote amplification of fibrogenic signals. Restoration of α-SMA in miR-223-overexpressing HSCs alleviated the antifibrotic effects of miR-223. Finally, to explore the therapeutic potential of miR-233 in liver fibrosis, we generated co-cultured organoids of HSCs with Huh7 hepatoma cells and challenged them with acetaminophen (APAP) or palmitic acid (PA) to induce hepatotoxicity. We showed that ectopic expression of miR-223 in HSCs attenuated fibrogenesis in the two human organoid models of liver injury, suggesting its potential application in antifibrotic therapy.

COVID-19 active case findings based on self-collected saliva samples with CRISPR-Cas12a detection

COVID-19 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus affecting the world population. Early detection has become one of the most successful strategies to alleviate the epidemic and pandemic of this contagious coronavirus. Surveillance testing programs have been initiated in many countries worldwide to prevent the outbreak of COVID-19. In this study, we demonstrated that our previously established clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a-based assay could detect variants of concern during 2021 in Thailand, including Alpha, Beta, and Delta strains as well as Omicron strain in early 2022. In combination with the newly designed saliva collection funnel, we established a safe, simple, economical, and efficient self-collection protocol for the COVID-19 screening process. We successfully utilized the assay in an active case finding with a total number of 578 asymptomatic participants to detect the SARS-CoV-2 in saliva samples. We finally demonstrated that the validation and evaluation in a large-scale setting could provide valuable information and elaborate the practicality of the test in real-world settings. Our optimized protocol yielded effective results with high sensitivity, specificity, and diagnostic accuracy (96.86%). In addition, this study demonstrates COVID-19 active case findings in low-resource settings, which would be feasible and attractive for surveillance and outbreak prevention in the future.

Abstract 3906: Characterization of mTORC2 interactome reveals association with microtubules in glioblastoma and neuroblastoma cells

The Mechanistic Target of Rapamycin Complex 2 (mTORC2) is a multiprotein complex representing one of the key players in the mTOR signaling pathway. This signal transduction is essential for the regulation of various cellular activities, including proper cell growth, proliferation, differentiation, survival, cell motility, and metabolism. Aberration of the mTOR cascade can be found in several types of disorders, including cancers and neurodegenerative diseases. It has been reported to correlate with acquired aggressive characteristics promoting metastasis, drug resistance, and recurrence in cancer cells and more progressive phenotypes in other diseased cells. More specifically, mTORC2 signaling promotes actin cytoskeleton reorganization, cell motility, cell survival, and has been recently reported to be responsible for DNA damage control. Unlike mTORC1 that has been more thoroughly studied, molecular mechanisms of mTORC2 are yet to be elaborated. Therefore, characterization of the mTORC2 signaling pathway will provide further information needed for better understandings of the biology of diseases. Previously, we have identified multiple cytoskeleton regulators, including actin-binding and microtubule-associated proteins as binding partners of mTORC2 in glioblastoma cells by affinity purification-mass spectrometry (AP-MS). In this work, we provided extensive characterization of mTORC2 interactome in both neuronal and non-neuronal cells focusing on microtubule-associated proteins. Interestingly, apart from many MAP proteins found in non-neuronal cells (glioblastoma), we identified Tau isoforms and their regulatory proteins such as Tau kinases from affinity-purified mTORC2 in neuroblastoma cells. The quantitative proteomic analyses of mTORC2-interacting proteins in various cellular conditions were performed to help determine the dynamics of the mTORC2-associated microtubule network. These novel protein-protein interactions acquired from this study suggested additional mTORC2 functions in different types of brain cells, which might also be beneficial to the understandings of neurodegenerative diseases in addition to cancers.

Citation Format: Narawit Pacharakullanon, Piriya Wongkongkathep, Fuyuhiko Tamanoi, Joseph A. Loo, Trairak Pisitkun, Naphat Chantaravisoot. Characterization of mTORC2 interactome reveals association with microtubules in glioblastoma and neuroblastoma cells [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 3906.

1355. Cluster of Multi-drug Resistance Neisseria gonorrhoeae Isolates with Reduce Ceftriaxone Susceptibility, First Report in Thailand

Background

Rapid emergence of global azithromycin resistance, with ceftriaxone reduce susceptibility/resistant strains, threatens the current recommends dual therapy with ceftriaxone and azithromycin for gonorrhea to ensure effective treatment. Thailand is a major risk area for gonorrhea because it as a key destination for sex tourism industry, where antibiotic resistance gonorrhea can spread easily and quickly across the region. Here, we identified a first cluster of Neisseria gonorrhoeae isolates with decreased ceftriaxone susceptibility in Thailand.

Methods

A 134 N. gonorrhoeae isolates collected from Thai Red Cross Anonymous Clinic, Bangkok, during 2016–2018 were studied. Broth micro-dilution and plate dilution methods to define resistance or decreased susceptibilityaccording to CLSI guidelines. Select isolates were subjected to whole genome sequencing with an Illumina MiSeq V2 instrument and analysis using CLCBio Genomics Workbench v6.5. Molecular docking studies were carried out to understand binding mode analysis and orientation of ceftriaxone in the active site of PBP2. Biofilm formation measured by confocal laser scanning microscopy.

Results

Among the N. gonorrhoeae clinical isolates, two isolates had significant reduced susceptibility to ceftriaxone (MICs of 0.125 mg/L), which were isolated from urethral swab in male heterosexual patients. Both were multidrug resistance and strong biofilm producers with ceftriaxone tolerance (MBEC > 128 mg/L). One isolate was resistant to azithromycin (MIC of 1 mg/L), and other one remained susceptible (MIC of 0.5 mg/L). Reduced susceptibility to ceftriaxone associated with alterations in PBP2, PBP1, PorB, MtrR, and mtrR promoter region with one belonged to ST7235 and second one had new allele number of tbpB with new sequence type (ST). Ceftriaxone weakly occupy the active site of mosaic XXXIV penicillin-binding protein 2 (PBP2) variant in both. Molecular epidemiology results reviled that both isolates display similarities with isolates from UK, USA, and Netherlands.

Conclusion

This first cluster of genetically related gonococcal isolates with decreased ceftriaxone susceptibility may bring threat of treatment failure in Thailand. Also highlighted the importance of maintaining surveillance for antimicrobial resistance.

Disclosures

All Authors: No reported disclosures

Novel colistin-EDTA combination for successful eradication of colistin-resistant Klebsiella pneumoniae catheter-related biofilm infections

Development of an effective therapy to overcome colistin resistance in Klebsiella pneumoniae, a common pathogen causing catheter-related biofilm infections in vascular catheters, has become a serious therapeutic challenge that must be addressed urgently. Although colistin and EDTA have successful roles for eradicating biofilms, no in vitro and in vivo studies have investigated their efficacy in catheter-related biofilm infections of colistin-resistant K. pneumoniae. In this study, colistin resistance was significantly reversed in both planktonic and mature biofilms of colistin-resistant K. pneumoniae by a combination of colistin (0.25-1 µg/ml) with EDTA (12 mg/ml). This novel colistin-EDTA combination was also demonstrated to have potent efficacy in eradicating colistin-resistant K. pneumoniae catheter-related biofilm infections, and eliminating the risk of recurrence in vivo. Furthermore, this study revealed significant therapeutic efficacy of colistin-EDTA combination in reducing bacterial load in internal organs, lowering serum creatinine, and protecting treated mice from mortality. Altered in vivo expression of different virulence genes indicate bacterial adaptive responses to survive in hostile environments under different treatments. According to these data discovered in this study, a novel colistin-EDTA combination provides favorable efficacy and safety for successful eradication of colistin-resistant K. pneumonia catheter-related biofilm infections.

Multidrug-resistant Neisseria gonorrhoeae infection in heterosexual men with reduced susceptibility to ceftriaxone, first report in Thailand

The global rapid emergence of azithromycin/ceftriaxone resistant Neisseria gonorrhoeae threatens current recommend azithromycin/ceftriaxone dual therapy for gonorrhea to ensure effective treatment. Here, we identified the first two N. gonorrhoeae isolates with decreased ceftriaxone susceptibility in Thailand. Among 134 N. gonorrhoeae isolates collected from Thai Red Cross Anonymous Clinic, Bangkok, two isolates (NG-083 and NG-091) from urethral swab in male heterosexual patients had reduced susceptibility to ceftriaxone (MICs of 0.125 mg/L). Both were multidrug resistant and strong biofilm producers with ceftriaxone tolerance (MBEC > 128 mg/L). NG-083 and NG-091 remained susceptible to azithromycin (MIC of 1 mg/L and 0.5 mg/L, respectively). Reduced susceptibility to ceftriaxone was associated with alterations in PBP2, PBP1, PorB, MtrR, and mtrR promoter region. NG-083 belonged to sequence type (ST) 7235 and NG-091 has new allele number of tbpB with new ST. Molecular docking revealed ceftriaxone weakly occupied the active site of mosaic XXXIV penicillin-binding protein 2 variant in both isolates. Molecular epidemiology results revealed that both isolates display similarities with isolates from UK, USA, and The Netherlands. These first two genetically related gonococcal isolates with decreased ceftriaxone susceptibility heralds the threat of treatment failure in Thailand, and importance of careful surveillance.

CAMSAP3 depletion induces lung cancer cell senescence-associated phenotypes through extracellular signal-regulated kinase inactivation

Background

Cellular senescence is an aging‐related process found in cancer cells that contributes to irreversible growth arrest and tumor aggressiveness. Recently, calmodulin‐regulated spectrin‐associated protein 3 (CAMSAP3), a minus‐end microtubule‐stabilizing protein, has received increasing attention in cancer cell biology. However, the biological role of CAMSAP3 on senescence in human lung cancer remains incompletely understood.

Methods

The function of CAMSAP3 on the regulation of cellular senescence‐associated phenotypes in human non‐small cell lung cancer H460 cells were determined in CAMSAP3 deletion (H460/C3ko) cells. The effects of CAMSAP3 on cell proliferation were investigated using MTT and colony formation assays. The cell cycle activity was evaluated by flow cytometry and the senescence‐associated phenotypes were observed by SA‐β‐Gal staining. Quantitative RT‐PCR and westen blot were used to evaluate the expression of cell cycle and senescence markers. Moreover, the interaction of CAMSAP3‐ERK1/2 and possible partner protein was quantified using immunoprecipitation/mass spectrometry and immunofluorescence. Lastly, an xenograft model were performed.

Results

CAMSAP3 knockout promotes lung cancer cell senescence‐associated phenotypes and induces G1 cell cycle arrest. Mechanistic investigation revealed that phosphorylated ERK (p‐ERK) was markedly downregulated in CAMSAP3‐deleted cells, suppressing cyclin D1 expression levels, and full‐length CAMSAP3 abrogated these phenotypes. Proteomic analysis demonstrated that vimentin, an intermediate filament protein, is required as a scaffold for CAMSAP3‐modulating ERK signaling. Furthermore, an in vivo tumor xenograft experiment showed that tumor initiation is potentially delayed in CAMSAP3 knockout tumors with the downregulation of p‐ERK and cyclin D1, resulting in a senescence‐like phenotype.

Conclusion

This study is the first to report an intriguing role of CAMSAP3 in lung carcinoma cell senescence‐associated phenotypes via the modulation of p‐ERK/cyclin D1 signaling.

Machine Learning-Driven and Smartphone-Based Fluorescence Detection for CRISPR Diagnostic of SARS-CoV-2

Rapid, accurate, and low-cost detection of SARS-CoV-2 is crucial to contain the transmission of COVID-19. Here, we present a cost-effective smartphone-based device coupled with machine learning-driven software that evaluates the fluorescence signals of the CRISPR diagnostic of SARS-CoV-2. The device consists of a three-dimensional (3D)-printed housing and low-cost optic components that allow excitation of fluorescent reporters and selective transmission of the fluorescence emission to a smartphone. Custom software equipped with a binary classification model has been developed to quantify the acquired fluorescence images and determine the presence of the virus. Our detection system has a limit of detection (LoD) of 6.25 RNA copies/μL on laboratory samples and produces a test accuracy of 95% and sensitivity of 97% on 96 nasopharyngeal swab samples with transmissible viral loads. Our quantitative fluorescence score shows a strong correlation with the quantitative reverse transcription polymerase chain reaction (RT-qPCR) Ct values, offering valuable information of the viral load and, therefore, presenting an important advantage over nonquantitative readouts.

Erratum: STING Mediates Lupus via the Activation of Conventional Dendritic Cell Maturation and Plasmacytoid Dendritic Cell Differentiation

[This corrects the article DOI: 10.1016/j.isci.2020.101530.].

Detection of severe acute respiratory syndrome coronavirus 2 and influenza viruses based on CRISPR-Cas12a

Due to the common symptoms of COVID-19, patients are similar to influenza-like illness. Therefore, the detection method would be crucial to discriminate between SARS-CoV-2 and influenza virus-infected patients. In this study, CRISPR-Cas12a-based detection was applied for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus, and influenza B virus which would be a practical and attractive application for screening of patients with COVID-19 and influenza in areas with limited resources. The limit of detection for SARS-CoV-2, influenza A, and influenza B detection was 10, 10³, and 10³ copies/reaction, respectively. Moreover, the assays yielded no cross-reactivity against other respiratory viruses. The results revealed that the detection of influenza virus and SARS-CoV-2 by using RT-RPA and CRISPR-Cas12a technology reaches 96.23% sensitivity and 100% specificity for SARS-CoV-2 detection. The sensitivity for influenza virus A and B detections was 85.07% and 94.87%, respectively. In addition, the specificity for influenza virus A and B detections was approximately 96%. In conclusion, the RT-RPA with CRISPR-Cas12a assay was an effective method for the screening of influenza viruses and SARS-CoV-2 which could be applied to detect other infectious diseases in the future.

STING Mediates Lupus via the Activation of Conventional Dendritic Cell Maturation and Plasmacytoid Dendritic Cell Differentiation

Signaling through stimulator of interferon genes (STING) leads to the production of type I interferons (IFN-Is) and inflammatory cytokines. A gain-of-function mutation in STING was identified in an autoinflammatory disease (STING-associated vasculopathy with onset in infancy; SAVI). The expression of cyclic GMP-AMP, DNA-activated cGAS-STING pathway, increased in a proportion of patients with SLE. The STING signaling pathway may be a candidate for targeted therapy in SLE. Here, we demonstrated that disruption of STING signaling ameliorated lupus development in Fcgr2b-deficient mice. Activation of STING promoted maturation of conventional dendritic cells and differentiation of plasmacytoid dendritic cells via LYN interaction and phosphorylation. The inhibition of LYN decreased the differentiation of STING-activated dendritic cells. Adoptive transfer of STING-activated bone marrow-derived dendritic cells into the FCGR2B and STING double-deficiency mice restored lupus phenotypes. These findings provide evidence that the inhibition of STING signaling may be a candidate targeted treatment for a subset of patients with SLE.

A rapid and simple method for routine determination of antibiotic sensitivity to biofilm populations of Pseudomonas aeruginosa

Treatment of infections by Pseudomonas aeruginosa forming biofilms after antimicrobial testing on planktonic bacteria can result in substantial failure. Therefore, we offer a robust and simple experimental platform to test the impact of antimicrobials on biofilms. Antibiotic response patterns varied uniquely within biofilm formation capacity and minimal biofilm eradication concentrations (MBECs) has a significantly better discriminatory power than minimum inhibitory concentrations (MICs) to differentiate the overall efficiency of antibiotics to eradicate biofilm. Our resazurin-based 96-well-plate platform is able to emulate bacterial responses to antibiotics under biofilm conditions in a fast, simple, and cost-effective screening method adaptable to automation, and warrants trials in the clinic.

Abstract 4535: The mTOR complex 2 promotes glioblastoma migration via the interactions with multiple actin-binding and microtubule-associated proteins

The mechanistic target of rapamycin complex 2 (mTORC2) is one of the two multiprotein complexes in the mTOR signaling pathway. It regulates several cellular activities such as cell survival, lipid metabolism, DNA damage control, and cell motility. The mTORC2 has been reported to be involved in the promotion of metabolic reprogramming, cancer migration, and cancer invasiveness in glioblastoma. However, underlying mechanisms and roles of this particular complex in glioblastoma migration has not been completely elucidated. Previously, we characterized the mTORC2-associated interactome by affinity purification-mass spectrometry (AP-MS) technique, identifying new RICTOR-interacting partners. In addition, we also investigated the localization of RICTOR under different culture conditions and found that it correlates with migration ability of the cancer cells. When mTORC2 activity is high resulting in increased migration, RICTOR tends to localize around the cell membrane. In this work, we further determined crucial players that interact with mTORC2 to control actin cytoskeleton and microtubule dynamics to promote migration. The results from quantitative proteomic analysis of mTORC2-associated interactome suggested that the amount of certain actin-binding proteins and microtubule-associated proteins significantly changed depending on mTORC2 activity level including Gelsolin, Myosin-9, Plectin, and MAP1B. When mTORC2 signaling was inhibited resulting in reduced migration, these proteins were found to be less interacting with mTORC2. Moreover, the results also indicated that active mTORC2 links both actin cytoskeleton and microtubules together to promote migration in glioblastoma cells. Depletion of RICTOR and inhibition of mTORC2 disrupted the connection between microtubules and cell membrane. Taken together, this work provided a plausible mechanism underlying the regulation of enhanced migration in brain cancer cells.

Citation Format: Naphat Chantaravisoot, Piriya Wongkongkathep, Narawit Pacharakullanon, Fuyuhiko Tamanoi, Joseph A. Loo, Trairak Pisitkun. The mTOR complex 2 promotes glioblastoma migration via the interactions with multiple actin-binding and microtubule-associated proteins [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4535.

Abstract 2702: The mTOR complex 2-associated interactome and cell migration ability determination in brain cancers

The mechanistic target of rapamycin complex 2 (mTORC2) is a multiprotein complex driving several cellular processes to promote metabolic activities, cell survival, cell proliferation, DNA damage control, and cell motility. It has been implicated as a critical player in tumorigenesis, metabolic reprogramming, and promotion of cancer aggressiveness. Since the functions of this particular complex have not been well understood, the characterization of mTORC2 and its signaling pathway is necessary for better understanding of known mTORC2-mediated function, to define new roles, and to identify more mTORC2 interacting partners in cancers, particularly ones with hyperactivated mTORC2 such as glioblastoma multiforme. GBM has been claimed as one of the most aggressive type cancers. In GBM cells, mTORC2 was reported to be regulating glioblastoma migration and invasion through the control of actin cytoskeleton reorganization and filamin A. Previously, we characterized mTORC2 by proteomic analysis using affinity purification coupled to mass spectromytry (AP-MS) technique. We were able to identify protein-protein interactions between RICTOR, a specific component of mTORC2, and associated proteins and revealed a number of mTORC2 interacting partners that have never been reported. These proteins include low-abundance proteins and less-characterized proteins. In this work, we further investigated more insights about the differences of mTORC2-associated interactomes under various conditions affecting cancer cell migration. We found the comparison between low-grade and high-grade glioma cell lines shows distinct groups of RICTOR-bound proteins. In addition, we have carried out migration assays and immunofluorescence staining experiments to determine cancer cell migration and localization of RICTOR and some of identified proteins under each culture condition. The results suggested that the information from proteomic analysis correlated with intracellular RICTOR localization and cell migration ability. EMT proteins and more cytoskeletal proteins were found in more motile and more invasive cells while nuclear proteins were identified when using low-grade glioma cells. Furthermore, we were able to use this approach to investigate cancer cell lines from other organs and found some relevance between mTORC2 complex localization and cell migration. Ultimately, these results will be analyzed together with the expression of other potential cancer markers to help determine the characteristics of brain cancers.

Citation Format: Naphat Chantaravisoot, Piriya Wongkongkathep, Narawit Pacharakullanon, Fuyuhiko Tamanoi, Joseph A. Loo, Trairak Pisitkun. The mTOR complex 2-associated interactome and cell migration ability determination in brain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2702.

52 Difference of Seminal Plasma Proteins in Good- and Poor-Freezability Boar Ejaculates

Seminal plasma is the semen components that maintain sperm metabolism, pH and osmolality. Fibronectin (FN1) and glutathione peroxidase (GPX5) are the seminal plasma proteins that play an important role on the boar sperm functions. The purpose of the present study was to determine the differences in GPX5 and FN1 contents in the boar semen having good, moderate, and poor freezability. A total of 38 ejaculates from 25 boars with proven fertility were included in the experiment. All the ejaculates included in the study had >70% subjective motility, >75% normal morphology, >75% sperm viability, and volume >100 mL per ejaculate. The semen was collected through semen collection bag with filter and split into 2 portions. The first portion was prepared for the evaluation of seminal plasma proteins (i.e. GPX5 and FN1) and the second portion was cryopreserved and evaluated for post-thaw semen qualities. The seminal plasma samples were collected in cryotube and plug into liquid nitrogen. The samples was stored at –80°C before protein extraction. After thawing, the ejaculates were classified into 3 groups according to their post-thawed sperm motility: poor (14.6 ± 3.9%), modersate (28.5 ± 4.1%), and good (64.0 ± 8.7%) freezability. The amounts of GPX5 and FN1 proteins were evaluated through Western blot analysis. The normalized quantity of proteins was compared among groups by one-way ANOVA. The normalized level of FN1 in seminal plasma was higher in good- than in poor-freezability groups (8.0 ± 0.8% v. 5.7 ± 0.7%, respectively; P < 0.05), but did not differ significantly compared with that of the moderate-freezability group (7.5 ± 0.8%; P > 0.05). The levels of GPX5 in good-, moderate-, and poor-freezability groups were 14.7 ± 3.0%, 16.8 ± 3.2%, and 10.9 ± 3.0%, respectively (P > 0.05). The level of FN1 in seminal plasma was significantly correlated with the post-thaw sperm progressive motility (r = 0.38, P = 0.01), total motility (r = 0.37, P = 0.02), and the proportion of bent tail sperm (r = –0.33, P = 0.04). The level of GPX5 was not correlated with any of the post-thaw sperm qualities (P > 0.05). However, the levels of GPX5 was positively correlated with FN1 (r = 0.40, P = 0.01, n = 38). It can be concluded that FN1 in seminal plasma can be used as a marker of sperm freezability in boar.

Abstract 219: Identification of the mechanistic target of rapamycin complex 2-associated interactome involved in brain cancer cell motility by affinity purification-mass spectrometry

The Mechanistic Target of Rapamycin Complex 2 (mTORC2), a multiprotein complex with serine-threonine kinase activity, drives several cellular processes of normal cells to promote proper metabolic activity, survival, proliferation, differentiation and movement. On the other hand, mTORC2 has been implicated as a critical player in tumorigenesis, stimulation of cell growth, cancer metabolic reprogramming, and development of highly migratory and invasive capabilities of cancers. Therefore, characterization of mTORC2 is necessary not only for better understandings of known mTORC2-mediated functions, but also for the discovery of new roles and more interacting partners of mTORC2 signaling network in cancers, particularly ones with hyperactivated mTORC2 such as glioblastoma. However, until now mTORC2 is still partially characterized. Previously, mTORC2 was reported to be associated with Filamin A and Myosin-9 which have been known to play important roles in cellular activities requiring locomotion, including cancer migration and invasion. The complex participates in regulating glioblastoma migration and invasion, and Filamin A acts as a physiological downstream target of mTORC2. Currently, proteomics has emerged as a powerful tool to identify, quantify, and examine a large number of proteins. Therefore, in order to extensively unravel mTORC2 signaling pathway, the use of proteomics is necessary.

We characterized mTORC2 by proteomic analysis based on affinity purification coupled to mass spectrometry (AP-MS) using antibodies against RICTOR, a specific component of mTORC2. The protein-protein interactions between RICTOR and other associated proteins were assessed. In addition to canonical components of mTORC2, the study has revealed more insights into a number of mTORC2 interacting partners which can be categorized and related to the main functions previously identified such as actin cytoskeleton reorganization, fatty acid metabolism, protein translation. Interestingly, we also found other types of cytoskeletal proteins, nucleotide metabolism, less-characterized and low abundance proteins associated with mTORC2 such as Hornerin and Desmoplakin. In addition, we have carried out the identification of condition-specific interactions for a dynamic view of mTORC2 interactome and found changes in the mTORC2-associated proteins from different conditions. Furthermore, proteomic approaches can also be relevant to investigation and prediction of mTORC2 upstream regulators, downstream targets, and complex localization. Ultimately, this project will uncover some unknown molecular mechanisms, and result in a significant impact on the field of signal transduction machinery in cancers.

Citation Format: Naphat Chantaravisoot, Piriya Wongkongkathep, Fuyuhiko Tamanoi, Trairak Pisitkun. Identification of the mechanistic target of rapamycin complex 2-associated interactome involved in brain cancer cell motility by affinity purification-mass spectrometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 219. doi:10.1158/1538-7445.AM2017-219

Significance of filamin A in mTORC2 function in glioblastoma

Background

Glioblastoma multiforme (GBM) is one of the most highly metastatic cancers. GBM has been associated with a high level of the mechanistic target of rapamycin complex 2 (mTORC2) activity. We aimed to observe roles of mTORC2 in GBM cells especially on actin cytoskeleton reorganization, cell migration and invasion, and further determine new important players involved in the regulation of these cellular processes.

Methods

To further investigate the significance of mTORC2 in GBM, we treated GBM cells with PP242, an ATP-competitive inhibitor of mTOR, and used RICTOR siRNA to knock down mTORC2 activity. Effects on actin cytoskeleton, focal adhesion, migration, and invasion of GBM cells were examined. To gain insight into molecular basis of the mTORC2 effects on cellular cytoskeletal arrangement and motility/invasion, we affinity purified mTORC2 from GBM cells and identified proteins of interest by mass spectrometry. Characterization of the protein of interest was performed.

Results

In addition to the inhibition of mTORC2 activity, we demonstrated significant alteration of actin distribution as revealed by the use of phalloidin staining. Furthermore, vinculin staining was altered which suggests changes in focal adhesion. Inhibition of cell migration and invasion was observed with PP242. Two major proteins that are associated with this mTORC2 multiprotein complex were found. Mass spectrometry identified one of them as Filamin A (FLNA). Association of FLNA with RICTOR but not mTOR was demonstrated. Moreover, in vitro, purified mTORC2 can phosphorylate FLNA likewise its known substrate, AKT. In GBM cells, colocalization of FLNA with RICTOR was observed, and the overall amounts of FLNA protein as well as phosphorylated FLNA are high. Upon treatments of RICTOR siRNA or PP242, phosphorylated FLNA levels at the regulatory residue (Ser2152) decreased. This treatment also disrupted colocalization of Actin filaments and FLNA.

Conclusions

Our results support FLNA as a new downstream effector of mTORC2 controlling GBM cell motility. This new mTORC2-FLNA signaling pathway plays important roles in motility and invasion of glioblastoma cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0396-z) contains supplementary material, which is available to authorized users.

Activating mutations of TOR (target of rapamycin)

Mammalian target of rapamycin (mTOR) is a key regulator of eukaryotic cell growth. In particular, mTORC1, one of the two complexes that contain mTOR, is involved in the regulation of protein synthesis, proliferation, cell cycle and autophagy. Hyperactivation of the mTOR signaling pathway is observed in human cancer. A variety of approaches including deletion analysis, yeast genetic screens and mining of human cancer genome databases were taken that resulted in the identification of activating mutations of TOR. These studies suggest that the FAT, FRB and kinase domains are the three regions of TOR where activating mutations can be identified. Within the kinase domain, the mutations are clustered in three hot spots that are all located in the kinase active site that was deduced by the alignment with PI3K. One of the hot spots corresponds to the region where PI3K oncogenic mutations have been identified. These results are beginning to provide important insights into the mechanism of activation of mTOR.