Decreased Expression of the Host Long-Noncoding RNA-GM Facilitates Viral Escape by Inhibiting the Kinase activity TBK1 via S-glutathionylation.

Viruses have evolved multiple strategies to evade elimination by the immune system. Here we examined the contribution of host long noncoding RNAs (lncRNAs) in viral immune evasion. By functional screening of lncRNAs whose expression decreased upon viral infection of macrophages, we identified a lncRNA (lncRNA-GM, Gene Symbol: AK189470.1) that promoted type I interferon (IFN-I) production and inhibited viral replication. Deficiency of lncRNA-GM in mice increased susceptibility to viral infection and impaired IFN-I production. Mechanistically, lncRNA-GM bound to glutathione S-transferase M1 (GSTM1) and blocked GSTM1 interaction with the kinase TBK1, reducing GSTM1-mediated S-glutathionylation of TBK1. Decreased S-glutathionylation enhanced TBK1 activity and downstream production of antiviral mediators. Viral infection reprogrammed intracellular glutathione metabolism and furthermore, an oxidized glutathione mimetic could inhibit TBK1 activity and promote viral replication. Our findings reveal regulation of TBK1 by S-glutathionylation and provide insight into the viral mediated metabolic changes that impact innate immunity and viral evasion.

Targeting NPM1 Epigenetically Promotes Postinfarction Cardiac Repair by Reprogramming Reparative Macrophage Metabolism.

BACKGROUND: Reparative macrophages play a crucial role in limiting excessive fibrosis and promoting cardiac repair after myocardial infarction (MI), highlighting the significance of enhancing their reparative phenotype for wound healing. Metabolic adaptation orchestrates the phenotypic transition of macrophages; however, the precise mechanisms governing metabolic reprogramming of cardiac reparative macrophages remain poorly understood. In this study, we investigated the role of NPM1 (nucleophosmin 1) in the metabolic and phenotypic shift of cardiac macrophages in the context of MI and explored the therapeutic effect of targeting NPM1 for ischemic tissue repair. METHODS: Peripheral blood mononuclear cells were obtained from healthy individuals and patients with MI to explore NPM1 expression and its correlation with prognostic indicators. Through RNA sequencing, metabolite profiling, histology, and phenotype analyses, we investigated the role of NPM1 in postinfarct cardiac repair using macrophage-specific NPM1 knockout mice. Epigenetic experiments were conducted to study the mechanisms underlying metabolic reprogramming and phenotype transition of NPM1-deficient cardiac macrophages. The therapeutic efficacy of antisense oligonucleotide and inhibitor targeting NPM1 was then assessed in wild-type mice with MI. RESULTS: NPM1 expression was upregulated in the peripheral blood mononuclear cells from patients with MI that closely correlated with adverse prognostic indicators of MI. Macrophage-specific NPM1 deletion reduced infarct size, promoted angiogenesis, and suppressed tissue fibrosis, in turn improving cardiac function and protecting against adverse cardiac remodeling after MI. Furthermore, NPM1 deficiency boosted the reparative function of cardiac macrophages by shifting macrophage metabolism from the inflammatory glycolytic system to oxygen-driven mitochondrial energy production. The oligomeric NPM1 recruited histone demethylase KDM5b to the promoter of Tsc1 (TSC complex subunit 1), the mTOR (mechanistic target of rapamycin kinase) complex inhibitor, reduced histone H3K4me3 modification, and inhibited TSC1 expression, which then facilitated mTOR-related inflammatory glycolysis and antagonized the reparative function of cardiac macrophages. The in vivo administration of antisense oligonucleotide targeting NPM1 or oligomerization inhibitor NSC348884 substantially ameliorated tissue injury and enhanced cardiac recovery in mice after MI. CONCLUSIONS: Our findings uncover the key role of epigenetic factor NPM1 in impeding postinfarction cardiac repair by remodeling metabolism pattern and impairing the reparative function of cardiac macrophages. NPM1 may serve as a promising prognostic biomarker and a valuable therapeutic target for heart failure after MI.

Allele-specific activation, enzyme kinetics, and inhibitor sensitivities of EGFR exon 19 deletion mutations in lung cancer.

Oncogenic mutations within the epidermal growth factor receptor (EGFR) are found in 15 to 30% of all non-small-cell lung carcinomas. The term exon 19 deletion (ex19del) is collectively used to refer to more than 20 distinct genomic alterations within exon 19 that comprise the most common EGFR mutation subtype in lung cancer. Despite this heterogeneity, clinical treatment decisions are made irrespective of which EGFR ex19del variant is present within the tumor, and there is a paucity of information regarding how individual ex19del variants influence protein structure and function. Herein, we identified allele-specific functional differences among ex19del variants attributable to recurring sequence and structure motifs. We built all-atom structural models of 60 ex19del variants identified in patients and combined molecular dynamics simulations with biochemical and biophysical experiments to analyze three ex19del mutations (E746_A750, E746_S752 > V, and L747_A750 > P). We demonstrate that sequence variation in ex19del alters oncogenic cell growth, dimerization propensity, enzyme kinetics, and tyrosine kinase inhibitor (TKI) sensitivity. We show that in contrast to E746_A750 and E746_S752 > V, the L747_A750 > P variant forms highly active ligand-independent dimers. Enzyme kinetic analysis and TKI inhibition experiments suggest that E746_S752 > V and L747_A750 > P display reduced TKI sensitivity due to decreased adenosine 5'-triphosphate Km. Through these analyses, we propose an expanded framework for interpreting ex19del variants and considerations for therapeutic intervention.

MOF-Derived ZrO2-Supported Bimetallic Pd-Ni Catalyst for Selective Hydrogenation of 1,3-Butadiene.

A series of MOF-derived ZrO2-supported Pd-Ni bimetallic catalysts (PdNi/UiO-67-CTAB(n)-A500) were prepared by co-impregnation and pyrolysis at 500 °C under air atmosphere using UiO-67-CTAB(n) (CTAB: cetyltrimethylammonium bromide; n: the concentration of CTAB; n = 0, 3, 8, 13, 18) as a sacrificial template. The catalytic activity of PdNi/UiO-66-CTAB(n)-A500 in 1,3-butadiene hydrogenation was found to be dependent on the crystal morphology of the UiO-67 template. The highest activity was observed over the PdNi/UiO-67-CTAB(3)-A500 catalyst which was synthesized using UiO-67-CTAB(3) with uniform octahedral morphology as the template for the 1,3-butadiene selective hydrogenation. The 1,3-butadiene conversion and total butene selectivity were 98.4% and 44.8% at 40 °C within 1 h for the PdNi/UiO-67-CTAB(3)-A500 catalyst, respectively. The catalyst of PdNi/UiO-67-CTAB(3)-A500 can be regenerated in flowing N2 at 200 °C. Carbon deposited on the surface of the catalyst was the main reason for its deactivation. This work is valuable for the high-efficiency bimetallic catalyst's development on the selective hydrogenation of 1,3-butadiene.

Single-cell transcriptome atlas reveals protective characteristics of COVID-19 mRNA vaccine.

Messenger RNA (mRNA) vaccines are promising alternatives to conventional vaccines in many aspects. We previously developed a lipopolyplex (LPP)-based mRNA vaccine (SW0123) that demonstrated robust immunogenicity and strong protective capacity against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in mice and rhesus macaques. However, the immune profiles and mechanisms of pulmonary protection induced by SW0123 remain unclear. Through high-resolution single-cell analysis, we found that SW0123 vaccination effectively suppressed SARS-CoV-2-induced inflammatory responses by inhibiting the recruitment of proinflammatory macrophages and increasing the frequency of polymorphonuclear myeloid-derived suppressor cells. In addition, the apoptotic process in both lung epithelial and endothelial cells was significantly inhibited, which was proposed to be one major mechanism contributing to vaccine-induced lung protection. Cell-cell interaction in the lung compartment was also altered by vaccination. These data collectively unravel the mechanisms by which the SW0123 protects against lung damage caused by SARS-CoV-2 infection.

Peptidoglycan recognition protein MsPGRP in largemouth bass (Micropterus salmoides) mediates immune functions with broad nonself recognition ability.

Peptidoglycan (PGN) recognition proteins (PGRPs) are important immune factors in innate immunity that function in recognising pathogens and activating the immune system. These ubiquitous proteins are conserved in invertebrates and vertebrates. In this study, a PGRP gene (MsPGRP) from largemouth bass (Micropterus salmoides) was identified and characterised, and its transcription distribution was explored. Recombinant protein (rMsPGRP) exhibited dose-dependent binding to PGN and glucan (GLU), but weak binding to lipopolysaccharide (LPS). MsPGRP exhibited agglutinating activity against several Gram-negative bacteria, Gram-positive bacteria and fungi, and it promoted phagocytosis activity of leukocytes against Micrococcus luteus and Aeromonas hydrophila. The protein also possessed amidase activity in the presence of Zn2+, degraded PGN, and disrupted the M. luteus cell wall. The results suggest that MsPGRP plays an important role in pathogen recognition, and acts as a opsonin during immune system responses and elimination of invading pathogens.

Application of Skeleton Data and Long Short-Term Memory in Action Recognition of Children with Autism Spectrum Disorder.

The recognition of stereotyped action is one of the core diagnostic criteria of Autism Spectrum Disorder (ASD). However, it mainly relies on parent interviews and clinical observations, which lead to a long diagnosis cycle and prevents the ASD children from timely treatment. To speed up the recognition process of stereotyped actions, a method based on skeleton data and Long Short-Term Memory (LSTM) is proposed in this paper. In the first stage of our method, the OpenPose algorithm is used to obtain the initial skeleton data from the video of ASD children. Furthermore, four denoising methods are proposed to eliminate the noise of the initial skeleton data. In the second stage, we track multiple ASD children in the same scene by matching distance between current skeletons and previous skeletons. In the last stage, the neural network based on LSTM is proposed to classify the ASD children's actions. The performed experiments show that our proposed method is effective for ASD children's action recognition. Compared to the previous traditional schemes, our scheme has higher accuracy and is almost non-invasive for ASD children.

Novel Marine Secondary Metabolites Worthy of Development as Anticancer Agents: A Review.

Secondary metabolites from marine sources have a wide range of biological activity. Marine natural products are promising candidates for lead pharmacological compounds to treat diseases that plague humans, including cancer. Cancer is a life-threatening disorder that has been difficult to overcome. It is a long-term illness that affects both young and old people. In recent years, significant attempts have been made to identify new anticancer drugs, as the existing drugs have been useless due to resistance of the malignant cells. Natural products derived from marine sources have been tested for their anticancer activity using a variety of cancer cell lines derived from humans and other sources, some of which have already been approved for clinical use, while some others are still being tested. These compounds can assault cancer cells via a variety of mechanisms, but certain cancer cells are resistant to them. As a result, the goal of this review was to look into the anticancer potential of marine natural products or their derivatives that were isolated from January 2019 to March 2020, in cancer cell lines, with a focus on the class and type of isolated compounds, source and location of isolation, cancer cell line type, and potency (IC50 values) of the isolated compounds that could be a guide for drug development.

Antibiotics Development and the Potentials of Marine-Derived Compounds to Stem the Tide of Multidrug-Resistant Pathogenic Bacteria, Fungi, and Protozoa.

As the search for new antibiotics continues, the resistance to known antimicrobial compounds continues to increase. Many researchers around the world, in response to antibiotics resistance, have continued to search for new antimicrobial compounds in different ecological niches such as the marine environment. Marine habitats are one of the known and promising sources for bioactive compounds with antimicrobial potentials against currently drug-resistant strains of pathogenic microorganisms. For more than a decade, numerous antimicrobial compounds have been discovered from marine environments, with many more antimicrobials still being discovered every year. So far, only very few compounds are in preclinical and clinical trials. Research in marine natural products has resulted in the isolation and identification of numerous diverse and novel chemical compounds with potency against even drug-resistant pathogens. Some of these compounds, which mainly came from marine bacteria and fungi, have been classified into alkaloids, lactones, phenols, quinones, tannins, terpenes, glycosides, halogenated, polyketides, xanthones, macrocycles, peptides, and fatty acids. All these are geared towards discovering and isolating unique compounds with therapeutic potential, especially against multidrug-resistant pathogenic microorganisms. In this review, we tried to summarize published articles from 2015 to 2019 on antimicrobial compounds isolated from marine sources, including some of their chemical structures and tests performed against drug-resistant pathogens.

Voruciclib, a Potent CDK4/6 Inhibitor, Antagonizes ABCB1 and ABCG2-Mediated Multi-Drug Resistance in Cancer Cells.

BACKGROUND/AIMS: The overexpression of ATP-Binding Cassette (ABC) transporters has known to be one of the major obstacles impeding the success of chemotherapy in drug resistant cancers. In this study, we evaluated voruciclib, a CDK 4/6 inhibitor, for its chemo-sensitizing activity in ABCB1- and ABCG2- overexpressing cells. METHODS: Cytotoxicity and reversal effect of voruciclib was determined by MTT assay. The intracellular accumulation and efflux of ABCB1 and ABCG2 substrates were measured by scintillation counter. The effects on expression and intracellular localization of ABCB1 and ABCG2 proteins were determined by Western blotting and immunofluorescence, respectively. Vanadate-sensitive ATPase assay was done to determine the effect of voruciclib on the ATPase activity of ABCB1 and ABCG2. Flow cytometric analysis was done to determine the effect of voruciclib on apoptosis of ABCB1 and ABCG2-overexpressing cells and docking analysis was done to determine the interaction of voruciclib with ABCB1 and ACBG2 protein. RESULTS: Voruciclib significantly potentiated the effect of paclitaxel and doxorubicin in ABCB1-overexpressing cells, as well as mitoxantrone and SN-38 in ABCG2-overexpressing cells. Voruciclib moderately sensitized ABCC10- overexpressing cells to paclitaxel, whereas it did not alter the cytotoxicity of substrates of ABCC1. Furthermore, voruciclib increased the intracellular accumulation and decreased the efflux of substrate anti-cancer drugs from ABCB1- or ABCG2-overexpressing cells. However, voruciclib did not alter the expression or the sub-cellular localization of ABCB1 or ABCG2. Voruciclib stimulated the ATPase activity of both ABCB1 and ABCG2 in a concentration-dependent manner. Lastly, voruciclib exhibited a drug-induced apoptotic effect in ABCB1- or ABCG2- overexpressing cells. CONCLUSION: Voruciclib is currently a phase I clinical trial drug. Our findings strongly support its potential use in combination with conventional anti-cancer drugs for cancer chemotherapy.

Patterned Synthesis of ZnO Nanorod Arrays for Nanoplasmonic Waveguide Applications.

We report the patterned synthesis of ZnO nanorod arrays of diameters between 50 nm and 130 nm and various spacings. This was achieved by patterning hole arrays in a polymethyl methacrylate layer with electron beam lithography, followed by chemical synthesis of ZnO nanorods in the patterned holes using the hydrothermal method. The fabrication of ZnO nanorod waveguide arrays is also demonstrated by embedding the nanorods in a silver film using the electroplating process. Optical transmission measurement through the nanorod waveguide arrays is performed and strong resonant transmission of visible light is observed. We have found the resonance shifts to a longer wavelength with increasing nanorod diameter. Furthermore, the resonance wavelength is independent of the nanowaveguide array period, indicating the observed resonant transmission is the effect of a single ZnO nanorod waveguide. These nanorod waveguides may be used in single-molecule imaging and sensing as a result of the nanoscopic profile of the light transmitted through the nanorods and the controlled locations of these nanoscale light sources.

A novel chemotherapeutic sensitivity-testing system based on collagen gel droplet embedded 3D-culture methods for hepatocellular carcinoma.

BACKGROUND: Patients suffering from advanced stage hepatocellular carcinoma (HCC) often exhibit a poor prognosis or dismal clinical outcomes due to ineffective chemotherapy or a multi-drug resistance (MDR) process. Thus, it is urgent to develop a new chemotherapeutic sensitivity testing system for HCC treatment. The presence study investigated the potential application of a novel chemotherapeutic sensitivity-testing system based on a collagen gel droplet embedded 3D-culture system (CD-DST). METHODS: Primary cells were separating from surgical resection specimens and then tested by CD-DST. To identify whether HCC cell lines or cells separating from clinical specimens contain MDR features, the cells were treated with an IC 50 (half maximal inhibitory concentration) or IC max (maximal inhibitory concentration) concentration of antitumor agents, e.g., 5-furuolouracil (5-FU), paclitaxel (PAC), cisplatin (CDDP), epirubicin (EPI), or oxaliplatin (L-OHP), and the inhibitory rates (IRs) were calculated. RESULTS: HepG2 cells were sensitive to 5-FU, PAC, CDDP, EPI, or L-OHP; the IC 50 value is 0.83 ± 0.45 µg/ml, 0.03 ± 0.02 µg/ml, 1.15 ± 0.75 µg/ml, 0.09 ± 0.03 µg/ml, or 1.76 ± 0.44 µg/ml, respectively. Only eight (8/26), nine (9/26), or five (5/26) patients were sensitive to the IC max concentration of CDDP, EPI, or L-OHP; whereas only three (3/26), four (4/26), or two (2/26) patients were sensitive to the IC 50 concentration of CDDP, EPI, or L-OHP. No patients were sensitive to 5-FU or PAC. CONCLUSIONS: The in vitro drug sensitivity exanimation revealed the MDR features of HCC and examined the sensitivity of HCC cells from clinical specimens to anti-tumor agents. CD-DST may be a useful method to predict the potential clinical benefits of anticancer agents for HCC patients.

Modulating the function of ATP-binding cassette subfamily G member 2 (ABCG2) with inhibitor cabozantinib.

Cabozantinib (XL184) is a small molecule tyrosine kinase receptor inhibitor, which targets c-Met and VEGFR2. Cabozantinib has been approved by the Food and Drug Administration to treat advanced medullary thyroid cancer and renal cell carcinoma. In the present study, we evaluated the ability of cabozantinib to modulate the function of the ATP-binding cassette subfamily G member 2 (ABCG2) by sensitizing cells that are resistant to ABCG2 substrate antineoplastic drugs. We used a drug-selected resistant cell line H460/MX20 and three ABCG2 stable transfected cell lines ABCG2-482-R2, ABCG2-482-G2, and ABCG2-482-T7, which overexpress ABCG2. Cabozantinib, at non-toxic concentrations (3 or 5µM), sensitized the ABCG2-overexpressing cells to mitoxantrone, SN-38, and topotecan. Our results indicate that cabozantinib reverses ABCG2-mediated multidrug resistance by antagonizing the drug efflux function of the ABCG2 transporter instead of downregulating its expression. The molecular docking analysis indicates that cabozantinib binds to the drug-binding site of the ABCG2 transporter. Overall, our findings demonstrate that cabozantinib inhibits the ABCG2 transporter function and consequently enhances the effect of the antineoplastic agents that are substrates of ABCG2. Cabozantinib may be a useful agent in anticancer treatment regimens for patients who are resistant to ABCG2 substrate drugs.

Osimertinib (AZD9291), a Mutant-Selective EGFR Inhibitor, Reverses ABCB1-Mediated Drug Resistance in Cancer Cells.

In recent years, tyrosine kinase inhibitors (TKIs) have been shown capable of inhibiting the ATP-binding cassette (ABC) transporter-mediated multidrug resistance (MDR). In this study, we determine whether osimertinib, a novel selective, irreversible EGFR (epidermal growth factor receptor) TKI, could reverse ABC transporter-mediated MDR. The results showed that, at non-toxic concentrations, osimertinib significantly sensitized both ABCB1-transfected and drug-selected cell lines to substrate anticancer drugs colchicine, paclitaxel, and vincristine. Osimertinib significantly increased the accumulation of [³H]-paclitaxel in ABCB1 overexpressing cells by blocking the efflux function of ABCB1 transporter. In contrast, no significant alteration in the expression levels and localization pattern of ABCB1 was observed when ABCB1 overexpressing cells were exposed to 0.3 µM osimertinib for 72 h. In addition, ATPase assay showed osimertinib stimulated ABCB1 ATPase activity. Molecular docking and molecular dynamic simulations showed osimertinib has strong and stable interactions at the transmembrane domain of human homology ABCB1. Taken together, our findings suggest that osimertinib, a clinically-approved third-generation EGFR TKI, can reverse ABCB1-mediated MDR, which supports the combination therapy with osimertinib and ABCB1 substrates may potentially be a novel therapeutic stategy in ABCB1-positive drug resistant cancers.

Esters of the marine-derived triterpene sipholenol A reverse P-GP-mediated drug resistance.

Our previous studies showed that several sipholane triterpenes, sipholenol A, sipholenone E, sipholenol L and siphonellinol D, have potent reversal effect for multidrug resistance (MDR) in cancer cells that overexpressed P-glycoprotein (P-gp/ABCB1). Through comparison of cytotoxicity towards sensitive and multi-drug resistant cell lines, we identified that the semisynthetic esters sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate potently reversed P-gp-mediated MDR but had no effect on MRP1/ABCC1 and BCRP/ABCG2-mediated MDR. The results from [3H]-paclitaxel accumulation and efflux studies suggested that these two triterpenoids were able to increase the intracellular accumulation of paclitaxel by inhibiting its active efflux. In addition, western blot analysis revealed that these two compounds did not alter the expression levels of P-gp when treated up to 72 h. These sipholenol derivatives also stimulated the ATPase activity of P-gp membranes, which suggested that they might be substrates of P-gp. Moreover, in silico molecular docking studies revealed the virtual binding modes of these two compounds into human homology model of P-gp. In conclusion, sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate efficiently inhibit the P-gp and may represent potential reversal agents for the treatment of multidrug resistant cancers.

The reversal of antineoplastic drug resistance in cancer cells by ß-elemene.

Multidrug resistance (MDR), defined as the resistance of cancer cells to compounds with diverse structures and mechanisms of actions, significantly limits the efficacy of antitumor drugs. A major mechanism that mediates MDR in cancer is the overexpression of adenosine triphosphate (ATP)-binding cassette transporters. These transporters bind to their respective substrates and catalyze their efflux from cancer cells, thereby lowering the intracellular concentrations of the substrates and thus attenuating or even abolishing their efficacy. In addition, cancer cells can become resistant to drugs via mechanisms that attenuate apoptosis and cell cycle arrest such as alterations in the p53, check point kinase, nuclear factor kappa B, and the p38 mitogen-activated protein kinase pathway. In this review, we discuss the mechanisms by which ß-elemene, a compound extracted from Rhizoma zedoariae that has clinical antitumor efficacy, overcomes drug resistance in cancer.

ARRY-334543 reverses multidrug resistance by antagonizing the activity of ATP-binding cassette subfamily G member 2.

ARRY-334543 is a small molecule inhibitor of ErbB1 and ErbB2 tyrosine kinases. We conducted this study to determine whether ARRY-334543 can enhance the efficacy of conventional anticancer drugs through interaction with ABC transporters. Lung cancer cell line NCI-H460 and its ABCG2-overexpressing NCI-H460/MX20, as well as the ABCG2-, ABCB1-, and ABCC10-overexpressing transfected cell lines were used for the reversal study. Our results demonstrated that ARRY-334543 (1.0 µM) significantly reversed ABCG2-mediated multidrug resistance (MDR) by directly inhibiting the drug efflux function of ABCG2, resulting in the elevated intracellular accumulation of chemotherapeutic drugs in the ABCG2-overexpressing cell lines. In addition, in isolated membranes, ARRY-334543 stimulated ATPase activity and inhibited photolabeling of ABCG2 with [(125)I]-iodoarylazidoprazosin in a concentration-dependent manner indicating that this drug directly interacts at the drug-binding pocket of this transporter. ARRY-334543 (1.0 µM) only slightly reversed ABCB1- and partially reversed ABCC10-mediated MDR suggesting that it exhibits high affinity toward ABCG2. Moreover, homology modeling predicted the binding conformation of ARRY-334543 at Arg482 centroid-based grid of ABCG2. However, ARRY-334543 at reversal concentrations did not affect the expression level of ABCG2, AKT and ERK1/2 and regulate the re-localization of ABCG2. We conclude that ARRY-334543 significantly reverses drug resistance mediated by ABCG2.

WHI-P154 enhances the chemotherapeutic effect of anticancer agents in ABCG2-overexpressing cells.

ATP-binding cassette (ABC) transmembrane proteins evidently decrease the intracellular accumulation of substrate chemotherapeutic drugs by extruding them against a concentration gradient, thereby inducing drug resistance. Here we reported the effect of WHI-P154, an irreversible inhibitor of Janus kinase 3 and epidermal growth factor receptor tyrosine kinases, on reversing ABC transporters-mediated drug resistance. We found that WHI-P154 significantly enhanced the sensitivity of ABCG2-overexpressing cells to its substrates. WHI-P154 moderately sensitized ABCB1-overexpressing KB-C2 cells to its substrates whereas showed no sensitizing effect on ABCC1-, ABCC2 or ABCC10-mediated drug resistance. Moreover, WHI-P154 produced a significant increase in the intracellular accumulation of [³H]-mitoxantrone in ABCG2-overexpressing cells. The expression levels nor the localization of the ABCG2 protein was altered after treatment of ABCG2-overexpressing cells with WHI-P154. Further studies indicated that WHI-P154 enhanced the ATPase activity of ABCG2 at low concentrations (<10 µM). Additionally, a docking model predicted the binding conformation of WHI-P154 within the transmembrane region of homology-modeled human ABCG2 transporter. Collectively, these findings highlighted WHI-P154 could significantly reverse ABCG2-mediated multidrug drug resistance by directly blocking the efflux function.

Lamellarin O, a pyrrole alkaloid from an Australian marine sponge, Ianthella sp., reverses BCRP mediated drug resistance in cancer cells.

ATP binding cassette (ABC) transporters, such as P-gp, BCRP and MRP1, can increase efflux of clinical chemotherapeutic agents and lead to multi-drug resistance (MDR) in cancer cells. While the discovery and development of clinically useful inhibitors has proved elusive to date, this molecular target nevertheless remains a promising strategy for addressing and potentially overcoming MDR. In a search for new classes of inhibitor, we used fluorescent accumulation and efflux assays supported by cell flow cytometry and MDR reversal assays, against a panel of sensitive and MDR human cancer cell lines, to evaluate the marine sponge co-metabolites 1-12 as inhibitors of P-gp, BCRP or MRP1 initiated MDR. These studies identified and characterized lamellarin O (11) as a selective inhibitor of BCRP mediated drug efflux. A structure-activity relationship analysis inclusive of the natural products 1-12 and the synthetic analogues 13-19, supported by in silico docking studies, revealed key structural requirements for the lamellarin O (11) BCRP inhibitory pharmacophore.

Expression and mechanism of regulation of PP2A/Pr65 in ameloblastoma.

OBJECTIVE: This study aimed to investigate the expression of PP2A/PR65 protein in ameloblastoma and the molecular mechanisms underlying the regulation of PP2A/PR65. The association between PP2A/PR65 and the clinicopathological characteristics of tumor specimens in ameloblastoma were to provide a theoretical basis for the diagnosis, therapy and prognosis of ameloblastoma. STUDY DESIGN: Streptavidin-peroxidase (S-P) immunohistochemical staining was used to detect PP2A/Pr65 expression changes in a total of 68 cases of ameloblastoma, six ameloblastic carcinomas, 21 squamous cell carcinomas and seven normal oral mucosas. Western blot was used to analyze PP2A/PR65 protein expression in 15 cases of ameloblastoma and three cases of normal oral mucosa. RESULTS: Of the 68 cases analyzed, four cases were negative, 25 cases were weakly positive, 20 cases were moderately positive and 19 cases were strongly positive. In six cases of ameloblastic carcinoma, three cases were weak positive, one case was positive, two cases were strongly positive and none were negative. In 21 cases of squamous cell carcinomas, three cases were negative, 17 cases were weakly positive, one case was moderately positive and none were strongly positive. Western blot analysis showed that, PP2A/Pr65 protein expression was lower in ameloblastoma tissue compared with normal oral mucosa. CONCLUSIONS: Reduced expression of PP2A/PR65 in ameloblastoma compared with normal oral mucosa indicates that PP2A/PR65 is involved in the occurrence and development of ameloblastoma.