A Biotinylated cpFIT-PNA Platform for the Facile Detection of Drug Resistance to Artemisinin in Plasmodium falciparum.

The evolution of drug resistance to many antimalarial drugs in the lethal strain of malaria (Plasmodium falciparum) has been a great concern over the past 50 years. Among these drugs, artemisinin has become less effective for treating malaria. Indeed, several P. falciparum variants have become resistant to this drug, as elucidated by specific mutations in the pfK13 gene. This study presents the development of a diagnostic kit for the detection of a common point mutation in the pfK13 gene of P. falciparum, namely, the C580Y point mutation. FIT-PNAs (forced-intercalation peptide nucleic acid) are DNA mimics that serve as RNA sensors that fluoresce upon hybridization to their complementary RNA. Herein, FIT-PNAs were designed to sense the C580Y single nucleotide polymorphism (SNP) and were conjugated to biotin in order to bind these molecules to streptavidin-coated plates. Initial studies with synthetic RNA were conducted to optimize the sensing system. In addition, cyclopentane-modified PNA monomers (cpPNAs) were introduced to improve FIT-PNA sensing. Lastly, total RNA was isolated from red blood cells infected with P. falciparum (WT strain - NF54-WT or mutant strain - NF54-C580Y). Streptavidin plates loaded with either FIT-PNA or cpFIT-PNA were incubated with the total RNA. A significant difference in fluorescence for mutant vs WT total RNA was found only for the cpFIT-PNA probe. In summary, this study paves the way for a simple diagnostic kit for monitoring artemisinin drug resistance that may be easily adapted to malaria endemic regions.

Drug-induced stress mediates Plasmodium falciparum ring-stage growth arrest and reduces in vitro parasite susceptibility to artemisinin.

During blood-stage infection, Plasmodium falciparum parasites are constantly exposed to a range of extracellular stimuli, including host molecules and drugs such as artemisinin derivatives, the mainstay of artemisinin-based combination therapies currently used as first-line treatment worldwide. Partial resistance of P. falciparum to artemisinin has been associated with mutations in the propeller domain of the Pfkelch13 gene, resulting in a fraction of ring stages that are able to survive exposure to artemisinin through a temporary growth arrest. Here, we investigated whether the growth arrest in ring-stage parasites reflects a general response to stress. We mimicked a stressful environment in vitro by exposing parasites to chloroquine or dihydroartemisinin (DHA). We observed that early ring-stage parasites pre-exposed to a stressed culture supernatant exhibited a temporary growth arrest and a reduced susceptibility to DHA, as assessed by the ring-stage survival assay, irrespective of their Pfkelch13 genotype. These data suggest that temporary growth arrest of early ring stages may be a constitutive, Pfkelch13-independent survival mechanism in P. falciparum.IMPORTANCEPlasmodium falciparum ring stages have the ability to sense the extracellular environment, regulate their growth, and enter a temporary growth arrest state in response to adverse conditions such as drug exposure. This temporary growth arrest results in reduced susceptibility to artemisinin in vitro. The signal responsible for this process is thought to be small molecules (less than 3 kDa) released by stressed mature-stage parasites. These data suggest that Pfkelch13-dependent artemisinin resistance and the growth arrest phenotype are two complementary but unrelated mechanisms of ring-stage survival in P. falciparum. This finding provides new insights into the field of P. falciparum antimalarial drug resistance by highlighting the extracellular compartment and cellular communication as an understudied mechanism.

Augmented drug resistance of osteosarcoma cells within decalcified bone matrix scaffold: The role of glutamine metabolism.

Due to the lack of a precise in vitro model that can mimic the nature microenvironment in osteosarcoma, the understanding of its resistance to chemical drugs remains limited. Here, we report a novel three-dimensional model of osteosarcoma constructed by seeding tumor cells (MG-63 and MNNG/HOS Cl no. 5) within demineralized bone matrix scaffolds. Demineralized bone matrix scaffolds retain the original components of the natural bone matrix (hydroxyapatite and collagen type I), and possess good biocompatibility allowing osteosarcoma cells to proliferate and aggregate into clusters within the pores. Growing within the scaffold conferred elevated resistance to doxorubicin on MG-63 and MNNG/HOS Cl no. 5 cell lines as compared to two-dimensional cultures. Transcriptomic analysis showed an increased enrichment for drug resistance genes along with enhanced glutamine metabolism in osteosarcoma cells in demineralized bone matrix scaffolds. Inhibition of glutamine metabolism resulted in a decrease in drug resistance of osteosarcoma, which could be restored by α-ketoglutarate supplementation. Overall, our study suggests that microenvironmental cues in demineralized bone matrix scaffolds can enhance osteosarcoma drug responses and that targeting glutamine metabolism may be a strategy for treating osteosarcoma drug resistance.

Natural small-molecules reverse Xeroderma Pigmentosum Complementation Group C (XPC) deficient-mediated drug-resistance in renal cell carcinoma.

BACKGROUND: Renal cancer is insensitive to radiotherapy or most chemotherapies. While the loss of the XPC gene was correlated with drug resistance in colon cancer, the expression of XPC and its role in the drug resistance of renal cancer have not yet been elucidated. With the fact that natural small-molecules have been adopted in combinational therapy with classical chemotherapeutic agents to increase the drug sensitivity and reduce adverse effects, the use of herbal compounds to tackle drug-resistance in renal cancer is advocated. PURPOSE: To correlate the role of XPC gene deficiency to drug-resistance in renal cancer, and to identify natural small-molecules that can reverse drug-resistance in renal cancer via up-regulation of XPC. METHODS: IHC was adopted to analyze the XPC expression in human tumor and adjacent tissues. Clinical data extracted from The Cancer Genome Atlas (TCGA) database were further analysed to determine the relationship between XPC gene expression and tumor staging of renal cancer. Two types of XPC-KD renal cancer cell models were established to investigate the drug-resistant phenotype and screen XPC gene enhancers from 134 natural small-molecules derived from herbal plants. Furthermore, the identified XPC enhancers were verified in single or in combination with FDA-approved chemotherapy drugs for reversing drug-resistance in renal cancer using MTT cytotoxicity assay. Drug resistance gene profiling, ROS detection assay, immunocytochemistry and cell live-dead imaging assay were adopted to characterize the XPC-related drug resistant mechanism. RESULTS: XPC gene expression was significantly reduced in renal cancer tissue compared with its adjacent tissue. Clinical analysis of TCGA database also identified the downregulated level of XPC gene in renal tumor tissue of stage IV patients with cancer metastasis, which was also correlated with their lower survival rate. 6 natural small-molecules derived from herbal plants including tectorigenin, pinostilbene, d-pinitol, polygalasaponin F, atractylenolide III and astragaloside II significantly enhanced XPC expression in two renal cancer cell types. Combinational treatment of the identified natural compound with the treatment of FDA-approved drug, further confirmed the up-regulation of XPC gene expression can sensitize the two types of XPC-KD drug-resistant renal cancer cells towards the FDA-approved drugs. Mechanistic study confirmed that GSTP1/ROS axis was activated in drug resistant XPC-KD renal cancer cells. CONCLUSION: XPC gene deficiency was identified in patient renal tumor samples, and knockdown of the XPC gene was correlated with a drug-resistant phenotype in renal cancer cells via activation of the GSTP1/ROS axis. The 6 identified natural small molecules were confirmed to have drug sensitizing effects via upregulation of the XPC gene. Therefore, the identified active natural small molecules may work as an adjuvant therapy for circumventing the drug-resistant phenotype in renal cancer via enhancement of XPC expression.

Insights into the preventive actions of natural compounds against Klebsiella pneumoniae infections and drug resistance.

Klebsiella pneumoniae is a type of Gram-negative bacteria that causes a variety of infections, including pneumonia, bloodstream infections, wound infections, and meningitis. The treatment of K. pneumoniae infection depends on the type of infection and the severity of the symptoms. Antibiotics are generally used to treat K. pneumoniae infections. However, some strains of K. pneumoniae have become resistant to antibiotics. This comprehensive review examines the potential of natural compounds as effective strategies against K. pneumonia infections. The alarming rise in antibiotic resistance underscores the urgent need for alternative therapies. This article represents current research on the effects of diverse natural compounds, highlighting their anti-microbial and antibiofilm properties against K. pneumonia. Notably, compounds such as andrographolide, artemisinin, baicalin, berberine, curcumin, epigallocatechin gallate, eugenol, mangiferin, piperine, quercetin, resveratrol, and thymol have been extensively investigated. These compounds exhibit multifaceted mechanisms, including disruption of bacterial biofilms, interference with virulence factors, and augmentation of antibiotic effectiveness. Mechanistic insights into their actions include membrane perturbation, oxidative stress induction, and altered gene expression. While promising, challenges such as limited bioavailability and varied efficacy across bacterial strains are addressed. This review further discusses the potential of natural compounds as better alternatives in combating K. pneumonia infection and emphasizes the need for continued research to harness their full therapeutic potential. As antibiotic resistance persists, these natural compounds offer a promising avenue in the fight against K. pneumonia and other multidrug-resistant pathogens.

Identification and drug resistance of pathogen of ulcerative skin disease and its immune responses and protective efficacy after vaccination in a giant spiny frog, Quasipaa spinosa.

OBJECTIVE: In order to explore the pathogen of the ulcerative skin disease in giant spiny frog (Quasipaa spinosa), and to provide theoretical basis for the prevention and control of the disease in practical production, this study was carried out to isolate and identify the pathogenic bacteria from the sick frogs suffering from rotting skin disease and to carry out the immunization test of the inactivated vaccine. METHODS: Physiological and biochemical characterization, and molecular biology of the pathogenic bacteria were identified, and drug screening and immunization responses were also carried out. RESULTS: The dominant bacterium QS01 was isolated from the lesions of diseased giant spiny frogs, which was confirmed to be the causative agent of the rotting skin disease of giant spiny frogs by artificial regression infection test. Based on the fact that the pathogen is a gram-negative short bacterium, its phenotypic characteristics and 16S rRNA and gyrB gene sequences were analyzed, and the bacterium was determined to be Citrobacter freundii. The results of the drug sensitivity test showed that the bacterium was sensitive to 11 antibiotics, including Enrofloxacin, Fleroxacin and Ciprofloxacin, including three non-polluting drugs such as Florfenicol, Roxithromycin and Thiamphenicol, as well as three Chinese herbal medicines such as Rheum officinale Baill, Coptis chinensis Franch and Scutellaria baicalensis Georgi. Most non-specific immune responses could go to recovery in 24h. The frogs were vaccinated with QS01 formaldehyde inactivated vaccine by injection, immersion and spraying, and the serum antibody potency of the three immunized groups with the average potency reached the peak at the 20th d after immunization, and the serum antibody potency of the injected immunized group was at the highest ratio of 1:64-128 (101.6), while the immersed group and the spraying group attained the ratio of 1:16-32 (20.2) and 1:16-32 (16) respectively, and lasted until the 30th d. The control group that was not immunized had the highest serum antibody potency of 1:16-32 (20.2) and 1:16-32 (16), and continued until the 30th d. The control group that was not immunized was not immunized. The serum antibody potency of the unimmunized control group was 1:2 to 2(2). The immunoprotection rates after takedown were 100 %, 85.71 % and 71.43 %, respectively. CONCLUSION: C. freundii is the pathogen of the disease in this farm, and the vaccination by immersion and spraying can effectively prevent and control the rotting skin disease in frogs. These results revealed pathogenicity of C. freundii and its activation of host immune response, which will provide a scientific reference for the aquaculture and disease prevention in Q. spinosa culture.

Influence of Rational use of Antibacterial Drugs on Drug Resistance of Pathogenic Bacteria in Nosocomial Infection.

The purpose of this study is to explore the impact of multi-departmental linkage and rational drug use supervision on the drug resistance of pathogenic bacteria in primary hospitals. Use the method of pharmacies and infection control departments to jointly develop hospital antimicrobial usage guidelines and reward and punishment systems to promote the rational use of antimicrobial drugs. In addition, clinicians and clinical pharmacists of the pharmacy department participated in the formulation of anti-infection programs, infection control departments and pharmacy supervision, and compared the rational use of antibacterial drugs, the time of antibacterial drug use, and the detection of drug-resistant bacteria between the two groups before and after the implementation of the mechanism. Our results showed that the rational use rates of medication indications, drug selection, drug dosage, and medication course in the observation group were 97.74%, 96.99%, 98.50%, and 96.24%, respectively, which were higher than 79.71% in the control group, 76.81%, 72.46% and 75.36%, the difference was statistically significant (P < .05); there was no statistically significant difference in the rational utilization rate of drug administration routes between the two groups (P > .05). The antibacterial drug use time of the observation group was (7.39±1.84) d shorter than that of the control group (13.53±2.61) d, and the difference was statistically significant (P < .05). The detection rate of drug-resistant bacteria in the observation group was 24.44%, which was lower than 42.86% in the control group, and the difference was statistically significant (P < .05). This shows that the grassroots multi-department linkage supervision mechanism is in line with the management model of standardizing the rational use of antimicrobial drugs at the grassroots level, and the intervention in the application of antibacterial drugs is conducive to improving the knowledge reserve of drug use among the grassroots people. The economic cost of reducing drug-resistant bacteria is huge. In addition to death and disability, long-term illness can result in longer hospital stays, the need for more expensive medications, and a significant financial burden on those affected. Therefore, improving the rationality of clinicians' medication use will help shorten treatment time and reduce drug-resistant bacteria. It is worthy of clinical promotion and application.

Acori Tatarinowii Rhizoma prevents the fluoxetine-induced multiple-drug resistance of Escherichia coli against antibiotics.

BACKGROUND: In treating depression, the residual anti-depressant in gut interacts with the microbiome, leading to the appearance of multiple drug resistant (MDR) mutants, which poses a challenge for the treatment of infectious complications. Strategy is needed to combat this issue. Acori Tatarinowii Rhizoma (ATR, rhizome of Acorus tatarinowii Schott, Araceae), a traditional Chinese medicine, has been widely used for treatment of neurological disorders and gastrointestinal digestive disease in China. Here, ATR was demonstrated an excellent MDR-preventing effect in fluoxetine-induced Escherichia coli (E. coli). AIM OF THE STUDY: This study aimed to reveal the effective role of ATR and its signaling cascades involved in preventing fluoxetine-induced MDR. MATERIALS AND METHODS: The water extract of ATR was co-applied with sub-minimum inhibitory concentration (100 mg/l) of fluoxetine in E. coli to evaluate its anti-MDR potential. Formation of reactive oxygen species (ROS) and expression of MDR-related genes in bacteria were measured by dichloro-dihydro-fluorescein diacetate assay and real-time PCR, respectively. Two fluorescent dyes, 1-N-phenylnapthylamine and 3,3'-dipropylthiadicarbocyanine were used to analyze the outer membrane permeability and inner membrane depolarization of E. coli. The accumulation of fluoxetine in the treated E. coli was determined via HPLC. The active fraction of ATR was identified. RESULTS: The water extract of ATR significantly decreased the number of MDR mutants induced by fluoxetine and had half effective concentrations (EC50) of 55.5 µg/ml and 16.8 µg/ml for chloramphenicol and tetracycline, respectively. ATR robustly reversed the fluoxetine-induced superoxide response and membrane damage in E. coli. In addition, the inclusion of ATR significantly reduced the accumulation of fluoxetine in E. coli. After further fractionation, the polysaccharide of ATR was demonstrated as the fraction with the most significant anti-MDR activity. CONCLUSIONS: This is the first report to investigate the MDR-preventing effect of ATR. The results of this study proposed ATR as an excellent herbal product to prevent MDR issues, as induced by fluoxetine, with the potential to reduce the side effects during the drug therapy of depression.

Evaluation of the ovicidal activity and fasciolicidal activity of the extract of ethyl acetate from Artemisia ludoviciana Nutt. spp. mexicana and of artemisinin against adult parasites of Fasciola hepatica.

The objective of this work was to evaluate the effect of the ethyl acetate extract from A. ludoviciana (EALM) and artemisinin against adult parasites and eggs of F. hepatica. For the ovicidal assay, cell culture plates with 24 wells were used, and 90 to 110 F. hepatica eggs were placed in each well. The eggs were exposed to concentrations of 100, 200, 300, 400, and 500 mg/L EALM and incubated for 16 days. Additionally, triclabendazole (TCBZ) was used as a reference drug at concentrations of 10 and 50 mg, and the response of artemisinin at concentrations of 10 and 20 mg was simultaneously assessed. Adult flukes were exposed to concentrations of 125, 250, 375, and 500 mg/L EALM. The results of the ovicidal action of EALM on the eggs showed that concentrations greater than 300 mg/L were significant, with ovicidal percentages greater than 60% observed on day 16 of incubation (p < 0.05). The maximum efficiency of EALM on adult flukes was reached 72 h post-exposure at a concentration of 125 mg/L (p < 0.05).

What exactly does the PfK13 C580Y mutation in Plasmodium falciparum influence?

BACKGROUND: The emergence and spread of artemisinin resistance threaten global malaria control and elimination goals, and encourage research on the mechanisms of drug resistance in malaria parasites. Mutations in Plasmodium falciparum Kelch 13 (PfK13) protein are associated with artemisinin resistance, but the unique or common mechanism which results in this resistance is unclear. METHODS: We analyzed the effects of the PfK13 mutation on the transcriptome and proteome of P. falciparum at different developmental stages. Additionally, the number of merozoites, hemozoin amount, and growth of P. falciparum 3D7C580Y and P. falciparum 3D7WT were compared. The impact of iron supplementation on the number of merozoites of P. falciparum 3D7C580Y was also examined. RESULTS: We found that the PfK13 mutation did not significantly change glycolysis, TCA, pentose phosphate pathway, or oxidative phosphorylation, but did reduce the expression of reproduction- and DNA synthesis-related genes. The reduced number of merozoites, decreased level of hemozoin, and slowed growth of P. falciparum 3D7C580Y were consistent with these changes. Furthermore, adding iron supply could increase the number of the merozoites of P. falciparum 3D7C580Y. CONCLUSIONS: These results revealed that the PfK13 mutation reduced hemoglobin ingestion, leading to artemisinin resistance, likely by decreasing the parasites' requirement for haem and iron. This study helps elucidate the mechanism of artemisinin resistance due to PfK13 mutations.

Wnt/ß-catenin signalling pathway in breast cancer cells and its effect on reversing tumour drug resistance by alkaloids extracted from traditional Chinese medicine.

Breast cancer is a high-risk disease with a high mortality rate among women. Chemotherapy plays an important role in the treatment of breast cancer. However, chemotherapy eventually results in tumours that are resistant to drugs. In recent years, many studies have revealed that the activation of Wnt/ß-catenin signalling is crucial for the emergence and growth of breast tumours as well as the development of drug resistance. Additionally, drugs that target this pathway can reverse drug resistance in breast cancer therapy. Traditional Chinese medicine has the properties of multi-target and tenderness. Therefore, integrating traditional Chinese medicine and modern medicine into chemotherapy provides a new strategy for reversing the drug resistance of breast tumours. This paper mainly reviews the possible mechanism of Wnt/ß-catenin in promoting the process of breast tumour drug resistance, and the progress of alkaloids extracted from traditional Chinese medicine in the targeting of this pathway in order to reverse the drug resistance of breast cancer.

The adcA and lmb Genes Play an Important Role in Drug Resistance and Full Virulence of Streptococcus suis.

Streptococcus suis is an recognized zoonotic pathogen of swine and severely threatens human health. Zinc is the second most abundant transition metal in biological systems. Here, we investigated the contribution of zinc to the drug resistance and pathogenesis of S. suis. We knocked out the genes of AdcACB and Lmb, two Zn-binding lipoproteins. Compared to the wild-type strain, we found that the survival rate of this double-mutant strain (ΔadcAΔlmb) was reduced in Zinc-limited medium, but not in Zinc-supplemented medium. Additionally, phenotypic experiments showed that the ΔadcAΔlmb strain displayed impaired adhesion to and invasion of cells, biofilm formation, and tolerance of cell envelope-targeting antibiotics. In a murine infection model, deletion of the adcA and lmb genes in S. suis resulted in a significant decrease in strain virulence, including survival rate, tissue bacterial load, inflammatory cytokine levels, and histopathological damage. These findings show that AdcA and Lmb are important for biofilm formation, drug resistance, and virulence in S. suis. IMPORTANCE Transition metals are important micronutrients for bacterial growth. Zn is necessary for the catalytic activity and structural integrity of various metalloproteins involved in bacterial pathogenic processes. However, how these invaders adapt to host-imposed metal starvation and overcome nutritional immunity remains unknown. Thus, pathogenic bacteria must acquire Zn during infection in order to successfully survive and multiply. The host uses nutritional immunity to limit the uptake of Zn by the invading bacteria. The bacterium uses a set of high-affinity Zn uptake systems to overcome this host metal restriction. Here, we identified two Zn uptake transporters in S. suis, AdcA and Lmb, by bioinformatics analysis and found that an adcA and lmb double-mutant strain could not grow in Zn-deficient medium and was more sensitive to cell envelope-targeting antibiotics. It is worth noting that the Zn uptake system is essential for biofilm formation, drug resistance, and virulence in S. suis. The Zn uptake system is expected to be a target for the development of novel antimicrobial therapies.

Bufalin serves as a pharmaceutic that mitigates drug resistance.

Intrinsic or acquired drug resistance of tumor cells is the main cause of tumor chemotherapy failure and tumor-related death. Bufalin (BF) is the main active monomer component extracted from the Traditional Chinese Medicine Toad venom (secretions of glands behind the ears and epidermis of bufo gargarizans and Bufo Melanostictus Schneider). It is a cardiotonic steroid with broad-spectrum anti-cancer effects and has been widely used against various malignant tumors in clinical practice. Pharmacological studies also found that BF has the effect of reversing drug resistance, which provides a new perspective for the application of Traditional Chinese Medicine as a chemosensitizer in cancer therapy. This article provides an extensive search and summary of published research on mitigating drug resistance to BF and reviews its potential mechanisms.

Evaluation of a combination of Citrus aurantium var. Dulcis essential oil and albendazole for the treatment of sheep gastrointestinal nematodes.

Citrus fruits are consumed all over the world and their by-products are used for animal feed and essential oils production. This study aimed to evaluate the in vitro and in vivo activity of Citrus aurantium var. Dulcis essential oil (CaEO) combined with ABZ against benzimidazole resistant Haemonchus contortus. In vitro egg hatching assays (EHA) were performed using CaEO and ABZ to estimate the effective concentration to achieve 50% egg death (EC50) values and calculate the test essential oil and drug combinations using a simplex-centroid mixture design. These concentrations were used for a second round of EHAs. Sixteen sheep were randomly allocated into two groups and treated with ABZ and the combination of CaEO and ABZ, and faecal egg count reduction tests were performed. In the first round of EHA, CaEO and ABZ showed EC50 values of 0.57 and 0.0048 mg mL-1, respectively. The H. contortus strain used in the study was shown to be highly benzimidazole resistant, with only 1.5% of parasites having susceptible ß-tubulin SNP genotypes. The ABZ reduced the shedding of nematode eggs by 78%, however, its combination with CaEO reduced faecal egg counts by only 9%. The present study is important to highlight the interferences of natural products in anthelmintic metabolism and consequently in drug efficacy.

Synthesis and biological evaluation of ruthenium complexes containing phenylseleny against Gram-positive bacterial infection by damage membrane integrity and avoid drug-resistance.

Compounds modified with selenium atom as potential antibacterial agents have been exploited to combat the nondrug-resistant bacterial infection. In this study, we designed and synthesized four ruthenium complexes retouching of selenium-ether. Fortunately, those four ruthenium complexes shown excellent antibacterial bioactive (MIC: 1.56-6.25 µg/mL) against Staphylococcus aureus (S. aureus), and the most active complex Ru(II)-4 could kill S. aureus by targeting the membrane integrity and avoid the bacteria to evolve drug resistance. Moreover, Ru(II)-4 was found to significantly inhibit the formation of biofilms and biofilm eradicate capacity. In toxicity experiments, Ru(II)-4 exhibited poor hemolysis and low mammalian toxicity. To illustrate the antibacterial mechanism: we conducted scanning electron microscope (SEM), fluorescent staining, membrane rupture and DNA leakage assays. Those results demonstrated that Ru(II)-4 could destroy the integrity of bacterial cell membrane. Furthermore, both G. mellonella wax worms infection model and mouse skin infection model were established to evaluate the antibacterial activity of Ru(II)-4 in vivo, the results indicated that Ru(II)-4 was a potential candidate for combating S. aureus infections, and almost non-toxic to mouse tissue. Thus, all the results indicated that introducing selenium-atom into ruthenium compounds were a promising strategy for developing interesting antibacterial agents.

Effect of liquiritigenin on chloroquine accumulation in digestive vacuole leading to apoptosis-like death of chloroquine-resistant P. falciparum.

BACKGROUND: Malaria remains one of the major health concerns, especially in tropical countries. Although drugs such as artemisinin-based combinations are efficient for treating Plasmodium falciparum, the growing threat from multi-drug resistance has become a major challenge. Thus, there is a constant need to identify and validate new combinations to sustain current disease control strategies to overcome the challenge of drug resistance in the malaria parasites. To meet this demand, liquiritigenin (LTG) has been found to positively interact in combination with the existing clinically used drug chloroquine (CQ), which has become unfunctional due to acquired drug resistance. PURPOSE: To evaluate the best interaction between LTG and CQ against CQ- resistant strain of P. falciparum. Furthermore, the in vivo antimalarial efficacy and possible mechanism of action of the best combination was also assessed. METHODS: The in vitro anti-plasmodial potential of LTG against CQ- resistant strain K1 of P. falciparum was tested using Giemsa staining method. The behaviour of the combinations was evaluated using the fix ratio method and evaluated the interaction of LTG and CQ by calculating the fractional inhibitory concentration index (FICI). Oral toxicity study was carried out in a mice model. In vivo antimalarial efficacy of LTG alone and in combination with CQ was evaluated using a four-day suppression test in a mouse model. The effect of LTG on CQ accumulation was measured using HPLC and the rate of alkalinization of the digestive vacuole. Cytosolic Ca2+ level, mitochondrial membrane potential, caspase-like activity, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and Annexin V Apoptosis assay to assess anti-plasmodial potential. Proteomics analysis was evaluated by LC-MS/MS analysis. RESULTS: LTG possesses anti-plasmodial activity on its own and it showed to be an adjuvant of CQ. In in vitro studies, LTG showed synergy with CQ only in the ratio (CQ: LTG-1:4) against CQ-resistant strain (K1) of P. falciparum. Interestingly, in vivo studies, LTG in combination with CQ showed higher chemo-suppression and enhanced mean survival time at much lower concentrations compared to individual doses of LTG and CQ against CQ- resistant strain (N67) of Plasmodium yoelli nigeriensis. LTG was found to increase the CQ accumulation into digestive vacuole, reducing the rate of alkalinization, in turn increasing cytosolic Ca2+ level, loss of mitochondrial potential, caspase-3 activity, DNA damage and externalization of phosphatidylserine of the membrane (in vitro). These observations indicate the involvement of apoptosis-like death of P. falciparum that might be due to the accumulation of CQ. CONCLUSION: LTG showed synergy with CQ in the ratio LTG: CQ, 4:1) in vitro and was able to curtail the IC50 of CQ and LTG. Interestingly, in vivo in combination with CQ, LTG showed higher chemo-suppression as well as enhanced mean survival time at a much lower concentrations of both the partners as compared to an individual dose of CQ and LTG. Thus, synergistic drug combination offers the possibility to enhance CQ efficacy in chemotherapy.

1550 nm light activatable photothermal therapy on multifunctional CuBi2O4 bimetallic particles for treating drug resistance bacteria-infected skin in the NIR-III biological window.

Nanomaterial mediated phototherapies are believed to be promising candidates to overcome the bacterial drug resistance crisis. However, due to the lack of nanomaterials able to absorb long NIR light, especially in the NIR-III (1500-1850 nm) and -IV (2100-2300 nm) regimes, it was never investigated the utilization of NIR-III and NIR-IV light for in vivo treatments of cancer or bacterial infections. To this end, plasmonic metal-doped transition metal oxides (TMO) are attracting a great attention due to their tunable surface plasmon resonance absorption to the NIR region. Unique features with extendable NIR light absorption of plasmonic metal-doped transition metal oxides make their applications very attractive in several fields, but their utilization for bacterial infection treatments was not yet reported. Moreover, up-to-date bacterial eradication was limited to phototherapies in the NIR-I (700-950 nm) and NIR-II (1000-1350 nm) biological windows (BWs) and has not yet been studied in the NIR-III (1500-1870 nm) BW. To overcome these literature limitations, we engineered NIR-III (1550 nm) light activatable multifunctional plasmonic CuBi2O4 bimetallic particles (i.e., CBO bMPs) with very high molar extinction coefficients (2.75 × 1011 M-1cm-1 @ 808 nm, 2.75 × 1011 M-1cm-1 @ 980 nm, and 3.5 × 1011 M-1cm-1 @1550 nm), able to absorb and convert long NIR (980 and 1550 nm) light energy to thermal heat and generate cytotoxic reactive oxygen species (ROS) for in vivo treatment of drug resistant bacterial infections. Our in vitro and in vivo results reveal that NIR-III (1550 nm) light irradiation of CBO bMPs exerts a remarkable in vivo antibacterial activity via NIR-III photothermal therapy (NIR-III PTT), which is superior than its corresponding NIR-I (808 nm) PTT and NIR-II photodynamic therapy (NIR-II PDT, 980 nm). We observed that hyperthermia-based photothermal therapy is more effective than ROS-based photodynamic therapy in killing multi-drug resistant bacteria. We also show that CBO bMPs also show an enzyme oxidase and peroxidase like activity, which is an additional asset to enhance the therapeutic efficiency.

GPR78 Regulates Autophagy and Drug Resistance in Non-small Cell Lung Cancer.

Context: Lung cancer is one of the most common forms of cancer. Autophagy and apoptosis play an important role in the development of lung cancer. Researchers have found upregulation of GRP78 expression in cancer cells of various types. Objective: The study intended to explore the mechanism of G protein-coupled receptor 78(GPR78) in regulating autophagy and drug resistance in non-small cell lung cancer (NSCLC). Design: The research team performed a laboratory study. Setting: The study took place in the Department of Thoracic Surgery at Hainan General Hospital of the Hainan Affiliated Hospital of Hainan Medical University in Haikou, Hainan, China. Intervention: The research team cultured immortalized, normal, human bronchial epithelial cells C3 (HBEC3) lines and HBEC4 lines in a serum medium without keratinocytes and infected the expression of GPR78 in knockdown A549 cells using lentiviral agents. The team divided the cells into a control group and a shRNA-GPR78 group, the intervention group. The lentiviral silencing vector expressing shRNA targets human GPR78#1 and GPR78 #2aadam10. Outcome Measures: The research team analyzed the mRNA expression of GPR78 in the NSCLC cell lines H1975, H1299, and A549 and in HBEC3 and HBEC4 using a real time-polymerase chain reaction (RT-PCR) and measured the proliferation of A549 cells at 0h, 24h, 48h, 72h, and 96h using yellow tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The team also analyzed the migration and invasion ability of cells using wound healing and Transwell tests as well as measured the protein expression of the autophagy-related factors Beclin-1, microtubule-associated protein light chain 3-I/II (LC3-I/LC3-II), ubiquitin-binding protein p62 and c-Jun N-terminal kinase (JNK) using a Western blot test. The team also analyzed the protein expressions of caspase-9, caspase-3, and caspase-12 related to apoptosis using a Western blot. To detect the cell viability induced by cisplatin, the team used a Cell Counting Kit 8 (CCK-8) at the concentrations of 1µM, 3µM and 10µM. Results: The mRNA expression of GPR78 in the H1975, H1299, and A549 cell lines was significantly higher than that in the HBEC3 and HBEC4 cell lines (P < .05). At 48h, 72h, and 96h, the A549 cell proliferation in the shRNA-GPR78 group was significantly lower than that of the control group (P < .05). The cell migration and invasion of cells in the shRNA-GPR78 group was significantly lower than that in the control group (P < .05), and the cell viability of the shRNA-GPR78 group was significantly lower than that of control group (P < .05). The expression of Beclin-1 and JNK protein in shRNA-GPR78 group was significantly higher than that in the control group (P < .05), and the expression of LC3-I/LC3-II and p62 protein in shRNA-GPR78 group was significantly lower than that in the control group (P < .05). The protein expressions of caspase-9, caspase-3, and caspase-12 in the shRNA-GPR78 group were significantly higher than those of the control group (P < .05), and the protein activities of RhoA and Rac1 in the shRNA-GPR78 group were significantly lower than those in the control group (P < .05). Conclusion: NSCLC upregulated GPR78. The knockdown of GPR78 can attenuate the proliferation, migration, and invasion of NSCLC cells and increase the apoptosis and autophagy of NSCLC cells that cisplatin has induced. Therefore, targeting GPR78 may be a promising treatment strategy for NSCLC patients.

Remodeling tumor microenvironment with natural products to overcome drug resistance.

With cancer incidence rates continuing to increase and occurrence of resistance in drug treatment, there is a pressing demand to find safer and more effective anticancer strategy for cancer patients. Natural products, have the advantage of low toxicity and multiple action targets, are always used in the treatment of cancer prevention in early stage and cancer supplement in late stage. Tumor microenvironment is necessary for cancer cells to survive and progression, and immune activation is a vital means for the tumor microenvironment to eliminate cancer cells. A number of studies have found that various natural products could target and regulate immune cells such as T cells, macrophages, mast cells as well as inflammatory cytokines in the tumor microenvironment. Natural products tuning the tumor microenvironment via various mechanisms to activate the immune response have immeasurable potential for cancer immunotherapy. In this review, it highlights the research findings related to natural products regulating immune responses against cancer, especially reveals the possibility of utilizing natural products to remodel the tumor microenvironment to overcome drug resistance.