P-glycoprotein Research Articles

Dual Deletion of Keap1 and Rbpjκ Genes in Liver Leads to Hepatomegaly and Hypercholesterolemia.

The hepatic deletion of Rbpjκ (RbpjF/F::AlbCre) in the mouse leads to exhibition of the Alagille syndrome phenotype during early postnatal liver development with hyperlipidemia and cholestasis due to attenuated disruption of NOTCH signaling. Given the roles of NRF2 signaling in the regulation of lipid metabolism and bile ductal formation, it was anticipated that these symptoms could be alleviated by enhancing NRF2 signaling in the RbpjF/F::AlbCre mouse by hepatic deletion of Keap1 in compound Keap1F/F::RbpjF/F::AlbCre mice. Unexpectedly, these mice developed higher hepatic and plasma cholesterol levels with more severe cholestatic liver damage during the pre-weaning period than in the RbpjF/F::AlbCre mice. In addition, hypercholesterolemia and hepatic damage were sustained throughout the growth period unlike in the RbpjF/F::AlbCre mouse. These enhanced abnormalities in lipid metabolism appear to be due to NRF2-dependent changes in gene expression related to cholesterol synthetic and subsequent bile acid production pathways. Notably, the hepatic expression of Cyp1A7 and Abcb11 genes involved in bile acid homeostasis was significantly reduced in Keap1F/F::RbpjF/F::AlbCre compared to RbpjF/F::AlbCre mice. The accumulation of liver cholesterol and the weakened capacity for bile excretion during the 3 pre-weaning weeks in the Keap1F/F::RbpjF/F::AlbCre mice may aggravate hepatocellular damage level caused by both excessive cholesterol and residual bile acid toxicity in hepatocytes. These results indicate that a tuned balance of NOTCH and NRF2 signaling is of biological importance for early liver development after birth.

Influence of Genetic Polymorphisms in CYP3A5, CYP3A4, and MDR1 on Tacrolimus Metabolism after kidney transplantation

Kidney transplantation stands as the ultimate recourse for restoring vital organ functions, particularly in cases of end-stage kidney disease where alternative treatments, such as dialysis, prove less effective. With over 102,000 kidney transplants conducted globally in 2022, the demand for organ transplantation is ever-increasing, fueled by a rising incidence of end-stage renal disease attributed to causes like diabetes and hypertension.<br /> Despite significant advancements in kidney transplantation, immunosuppressive therapy remains crucial to preventing graft rejection. Tacrolimus (TAC), a calcineurin inhibitor, plays a pivotal role in this regard. Discovered in 1984, TAC inhibits T-lymphocyte activation, preventing acute rejection by disrupting the transcription of crucial genes involved in early T-cell activation. However, the use of TAC is not without challenges. The drug exhibits serious side effects, a narrow therapeutic index, and unpredictable pharmacokinetics. Therapeutic drug monitoring (TDM) becomes imperative in daily practice to maintain TAC blood concentrations within the therapeutic range. This literature review delves into the genetic aspects influencing TAC metabolism, focusing on key polymorphisms in CYP3A5, CYP3A4, and ABCB1 genes. Genetic variations in CYP3A5, a major enzyme in TAC metabolism, impact enzyme activity, necessitating personalized dosing strategies. CYP3A4 polymorphisms, especially CYP3A4*22, demonstrate associations with altered TAC clearance and dose requirements. The ABCB1 gene, encoding P-glycoprotein, another player in TAC pharmacokinetics, also exhibits polymorphisms influencing drug absorption and distribution. The ABCB1 3435C>T variant, in particular, shows potential implications on Tacrolimus bioavailability. Understanding these genetic variations aids in the development of personalized dosing regimens. Studies suggest that tailoring TAC doses based on CYP3A5 genotypes significantly improves the proportion of patients achieving therapeutic concentrations. Additionally, incorporating genetic information, particularly CYP3A4*22, into dosing strategies enhances the precision of TAC therapy, reducing the risk of adverse effects.

Spontaneous fermentation mitigates the frequency of genes encoding antimicrobial resistance spreading from the phyllosphere reservoir to the diet

The phyllosphere microbiome of vegetable products constitutes an important reservoir for multidrug resistant bacteria and Antibiotic Resistance Genes (ARG). Vegetable products including fermented products such as Paocai therefore may serve as a shuttle for extrinsic microorganisms with ARGs into the gut of consumers. Here we study the effect of fermentation on Paocai ARG dissemination by metagenomic analysis. Microbial abundance and diversity of the Paocai microbiome were diminished during fermentation, which correlated with the reduction of abundance in ARGs. Specifically, as fermentation progressed, Enterobacterales overtook Pseudomonadales as the predominant ARG carriers, and Lactobacillales and Enterobacteriales became the determinants of Paocai resistome variation. Moreover, the dual effect of microbes and metal resistance genes (MRGs) was the major contributor driving Paocai resistome dynamics. We recovered several metagenome-assembled genomes (MAGs) carrying acquired ARGs in the phyllosphere microbiome. ARGs of potential clinical and epidemiological relevance such as tet M and emrB-qacA, were mainly hosted by non-dominant bacterial genera. Overall, our study provides evidence that changes in microbial community composition by fermentation aid in constraining ARG dispersal from raw ingredients to the human microbiome but does not eliminate them.

A Genome-Wide Comparative Analysis of AUX1/LAX, PIN, and ABCB Genes Reveals Their Roles in Cucumber Fruit Curving

Auxin transport is regulated by the AUX1/LAX, PIN, and ABCB gene families, controlling the distribution of auxin and ultimately fruit curving in cucumbers. However, studies on the differential expression of these auxin transporters and their roles in fruit curving are limited. In this study, we identified 36 auxin transporters from cucumber, including CsLAX1–7, CsPIN1–10, and CsABCB1–19. Basic characteristic analysis revealed that all CsLAX proteins were conservative, and a C-terminal NPNTY motif was found in CsPIN1–4/7–10. CsABCB1/5/11/14/17 were categorized as half-size transporters. Phylogenetic analysis revealed a genetic relationship between auxin transporters in Arabidopsis and cucumber. Exogenous auxin treatment on fruits and qPCR analysis indicated that differential expression patterns of auxin transporters control cucumber fruit curving. Co-expression analysis indicated that CsPIN1 and CsLAX2 were substantially negatively correlated, and they displayed opposite expression patterns in curved fruits. A proposed model suggested that CsLAX2 transports extracellular auxin to the convex side of the fruit; however, CsPIN1 inhibits auxin efflux at the same location. This leads to uneven auxin distribution that results in cucumber fruit curving.

Plastiome: Plastisphere-enriched mobile resistome in aquatic environments

Aquatic microplastics (MPs) act as reservoirs for microbial communities, fostering the formation of a mobile resistome encompassing diverse antibiotic (ARGs) and biocide/metal resistance genes (BMRGs), and mobile genetic elements (MGEs). This collective genetic repertoire, referred to as the “plastiome,” can potentially perpetuate environmental antimicrobial resistance (AMR). Our study examining two Japanese rivers near Tokyo revealed that waterborne MPs are primarily composed of polyethylene and polypropylene fibers and sheets of diverse origin. Clinically important genera like Exiguobacterium and Eubacterium were notably enriched on MPs. Metagenomic analysis uncovered a 3.46-fold higher enrichment of ARGs on MPs than those in water, with multidrug resistance genes (MDRGs) and BMRGs prevailing, particularly within MPs. Specific ARG and BMRG subtypes linked to resistance to vancomycin, beta-lactams, biocides, arsenic, and mercury showed selective enrichment on MPs. Network analysis revealed intense associations between host genera with ARGs, BMRGs, and MGEs on MPs, emphasizing their role in coselection. In contrast, river water exhibited weaker associations. This study underscores the complex interactions shaping the mobile plastiome in aquatic environments and emphasizes the global imperative for research to comprehend and effectively control AMR within the One Health framework.

Population characteristics of pathogenic Escherichia coli in puerperal metritis of dairy cows in Ningxia region of China: a systemic taxa distribution of virulence factors and drug resistance genes.

Escherichia coli (E. coli) is closely associated with the occurrence of puerperal metritis in dairy cows. E. coli carries some the virulence and multi-drug resistant genes, which pose a serious threat to the health of postpartum cows. In this study, E. coli was isolated and identified from the uterine contents of postpartum cows with puerperal metritis in the Ningxia region of China, and its phylogenetic subgroups were determined. Meanwhile, virulence and drug resistance genes carried by E. coli and drug sensitivity were detected, and the characteristics of virulence and drug resistance genes distribution in E. coli phylogroups were further analyzed. The results showed that the isolation rate of E. coli in puerperal metritis samples was 95.2%. E. coli was mainly divided into phylogroups B2 and D, followed by groups A and B1, and was more connected to O157:H7, O169:H4, and ECC-1470 type strains. The virulence genes were mainly dominated by ompF (100%), traT (100%), fimH (97%), papC (96%), csgA (95%), Ang43 (93.9%), and ompC (93%), and the resistance genes were dominated by TEM (99%), tetA (71.7%), aac(3)II (66.7%), and cmlA (53.5%). Additionally, it was observed that the virulence and resistance gene phenotypes could be divided into two subgroups, with subgroup B2 and D having the highest distributions. Drug sensitivity tests also revealed that the E. coli was most sensitive to the fluoroquinolones enrofloxacin, followed by macrolides, aminoglycosides, tetracyclines, β-lactams, peptides and sulfonamides, and least sensitive to lincosamides. These results imply that pathogenic E. coli, which induces puerperal metritis of dairy cows in the Ningxia region of China, primarily belongs to the group B2 and D, contains multiple virulence and drug resistance genes, Moreover, E. coli has evolved resistance to several drugs including penicillin, lincomycin, cotrimoxazole, and streptomycin. It will offer specific guidelines reference for the prevention and treatment of puerperal metritis in dairy cows with E. coli infections in the Ningxia region of China.

Association of CYP3A4-392A/G, CYP3A5-6986A/G, and ABCB1-3435C/T Polymorphisms with Tacrolimus Dose, Serum Concentration, and Biochemical Parameters in Mexican Patients with Kidney Transplant.

Forty-six kidney transplant recipients (KTR) receiving immunosuppressive treatment with TAC in different combinations were included. CYP3A4, CYP3A5, and ABCB1 gene polymorphisms were genotyped using qPCR TaqMan. Serum TAC concentration (as measured) and intervening variables were assessed. Logistic regression analyses were performed at baseline and after one month to assess the extent of the association between the polymorphisms, intervening variables, and TAC concentration. The GG genotype of CYP3A5-6986 A/G polymorphism is associated with TAC pharmacokinetic variability OR 4.35 (95%CI: 1.13-21.9; p = 0.0458) at one month of evolution; in multivariate logistic regression, CYP3A5-6986GG genotype OR 9.32 (95%CI: 1.54-93.08; p = 0.028) and the use of medications or drugs that increase serum TAC concentration OR 9.52 (95%CI: 1.79-88.23; p = 0.018) were strongly associated with TAC pharmacokinetic variability. The findings of this study of the Mexican population showed that CYP3A5-6986 A/G GG genotype is associated with a four-fold increase in the likelihood of encountering a TAC concentration of more than 15 ng/dL. The co-occurrence of the CYP3A5-6986GG genotype and the use of drugs that increase TAC concentration correlates with a nine-fold increased risk of experiencing a TAC at a level above 15 ng/mL. Therefore, these patients have an increased susceptibility to TAC-associated toxicity.

Metagenomic and transcriptomic analysis revealing the impact of oxytetracycline and ciprofloxacin on gut microbiota and gene expression in the Chinese giant salamander (Andrias davidianus)

Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on amphibian populations remain unclear. We investigated the impact of oxytetracycline (OTC) and ciprofloxacin (CIP) on Chinese giant salamanders (Andrias davidianus), focusing on gut microbiota, ARGs, and gene expression by performing metagenome and transcriptome sequencing. A. davidianus were given OTC (20 or 40 mg/kg) or CIP (50 or 100 mg/kg) orally for 7 days. The results revealed that oral administration of OTC and CIP led to distinct changes in microbial composition and functional potential, with CIP treatment having a greater impact than OTC. Antibiotic treatment also influenced the abundance of ARGs, with an increase in fluoroquinolone and multi-drug resistance genes observed post-treatment. The construction of metagenome-assembled genomes (MAGs) accurately validated that CIP intervention enriched fish-associated potential pathogens Aeromonas hydrophila carrying an increased number of ARGs. Additionally, mobile genetic elements (MGEs), such as phages and plasmids, were implicated in the dissemination of ARGs. Transcriptomic analysis of the gut revealed significant alterations in gene expression, particularly in immune-related pathways, with differential effects observed between OTC and CIP treatments. Integration of metagenomic and transcriptomic data highlighted potential correlations between gut gene expression and microbial composition, suggesting complex interactions between the host gut and its gut microbiota in response to antibiotic exposure. These findings underscore the importance of understanding the impact of antibiotic intervention on the gut microbiome and host health in amphibians, particularly in the context of antibiotic resistance and immune function.

Hyaluronic Acid Prevents Fusion of Brain Tumor-Derived Spheroids and Selectively Alters Their Gene Expression Profile.

Hyaluronic acid (HA), a major glycosaminoglycan of the brain extracellular matrix, modulates cell behaviors through binding its receptor, Cd44. In this study, we assessed the influence of HA on high-grade brain tumors in vitro. The model comprised cell cultures derived from six rodent carcinogen-induced brain tumors, forming 3D spheroids prone to spontaneous fusion. Supplementation of the standard culture medium with 0.25% HA significantly inhibited the fusion rates, preserving the shape and size uniformity of spheroids. The 3D cultures were assigned to two groups; a Cd44lo group had a tenfold decreased relative expression of Cd44 than another (Cd44hi) group. In addition, these two groups differed by expression levels of Sox2 transcription factor; the correlation analysis revealed a tight negative association for Cd44 and Sox2. Transcriptomic responses of spheroids to HA exposure also depended on Cd44 expression levels, from subtle in Cd44lo to more pronounced and specific in Cd44hi, involving cell cycle progression, PI3K/AKT/mTOR pathway activation, and multidrug resistance genes. The potential HA-induced increase in brain tumor 3D models' resistance to anticancer drug therapy should be taken into account when designing preclinical studies using HA scaffold-based models. The property of HA to prevent the fusion of brain-derived spheroids can be employed in CNS regenerative medicine and experimental oncology to ensure the production of uniform, controllably fusing neurospheres when creating more accurate in vitro brain models.

Factors Influencing Mortality in Children with Central Nervous System Tumors: A Cohort Study on Clinical Characteristics and Genetic Markers.

Multidrug resistance (MDR) commonly leads to cancer treatment failure because cancer cells often expel chemotherapeutic drugs using ATP-binding cassette (ABC) transporters, which reduce drug levels within the cells. This study investigated the clinical characteristics and single nucleotide variant (SNV) in ABCB1, ABCC1, ABCC2, ABCC4, and ABCG2, and their association with mortality in pediatric patients with central nervous system tumors (CNST). Using TaqMan probes, a real-time polymerase chain reaction genotyped 15 SNPs in 111 samples. Patients were followed up until death or the last follow-up day using the Cox proportional hazards model. An association was found between the rs1045642 (ABCB1) in the recessive model (HR = 2.433, 95% CI 1.098-5.392, p = 0.029), and the ICE scheme in the codominant model (HR = 9.810, 95% CI 2.74-35.06, p ≤ 0.001), dominant model (HR = 6.807, 95% CI 2.87-16.103, p ≤ 0.001), and recessive model (HR = 6.903, 95% CI 2.915-16.544, p = 0.038) significantly increased mortality in this cohort of patients. An association was also observed between the variant rs3114020 (ABCG2) and mortality in the codominant model (HR = 5.35, 95% CI 1.83-15.39, p = 0.002) and the dominant model (HR = 4.421, 95% CI 1.747-11.185, p = 0.002). A significant association between the ICE treatment schedule and increased mortality risk in the codominant model (HR = 6.351, 95% CI 1.831-22.02, p = 0.004, HR = 9.571, 95% CI 2.856-32.07, p ≤ 0.001), dominant model (HR = 6.592, 95% CI 2.669-16.280, p ≤ 0.001), and recessive model (HR = 5.798, 95% CI 2.411-13.940, p ≤ 0.001). The genetic variants rs3114020 in the ABCG2 gene and rs1045642 in the ABCB1 gene and the ICE chemotherapy schedule were associated with an increased mortality risk in this cohort of pediatric patients with CNST.

SiRNA-Mediated Knockdown of ABCB1 Enhances the Efficacy of Doxorubicin and Vinorelbine in Breast Cancer Cells.

Breast cancer remains a leading cause of cancer-related deaths among women, primarily attributed to the formidable challenge of multidrug resistance, often driven by the overexpression of the ABCB1 gene. This study aimed to assess the synergistic effects of siRNA, doxorubicin, and vinorelbine on ABCB1 gene expression and cell viability in doxorubicin-resistant MCF-7/ADR breast cancer cells, with siRNA targeting ABCB1 to reduce its expression and doxorubicin/ vinorelbine to eradicate cancer cells. Our methodology involved culturing MCF-7 and MCF-7/ADR cells in standard cell culture conditions. The synthesized siRNA sequences transfected cells with siRNA at final concentrations of 10, 20, and 30 nM and assessed cell viability using the MTT assay was performed. Real-time PCR was employed to quantify ABCB1 mRNA expression levels. Results indicated that MCF-7/ADR cells exhibited substantial resistance to vinorelbine and doxorubicin compared to MCF-7 cells, displaying resistance at 12.50 μM and 25.00 μM for vinorelbine and 6.25 μM and 25.00 μM for doxorubicin. Remarkably, siRNA treatment effectively reversed drug resistance in MCF-7/ADR cells across all concentrations of vinorelbine and doxorubicin tested. When combined, siRNA, doxorubicin, and vinorelbine yielded a significantly greater reduction in cell viability compared to individual drug treatments, particularly at a 20 μM siRNA concentration. This combination therapy also significantly suppressed ABCB1 gene expression by a factor of 41.48 in MCF-7 cells relative to MCF-7/ADR cells. these findings suggest that combining siRNA, doxorubicin, and vinorelbine holds promise as a therapeutic strategy to overcome ABCB1-mediated multidrug resistance in breast cancer. Further investigations and clinical trials are warranted to evaluate its clinical efficacy rigorously.

Variations in antimicrobial resistance genes present in the rectal faeces of seals in Scottish and Liverpool Bay coastal waters

Antibiotic resistance genes originating from human activity are considered important environmental pollutants. Wildlife species can act as sentinels for coastal environmental contamination and in this study we used qPCR array technology to investigate the variety and abundance of antimicrobial resistance genes (ARGs), mobile genetic elements (MGEs) and integrons circulating within seal populations both near to and far from large human populations located around the Scottish and northwest English coast. Rectal swabs were taken from 50 live grey seals and nine live harbour seals. Nucleic acids were stabilised upon collection, enabling extraction of sufficient quality and quantity DNA for downstream analysis. 78 ARG targets, including genes of clinical significance, four MGE targets and three integron targets were used to monitor genes within 22 sample pools. 30 ARGs were detected, as well as the integrons intl1 and intl2 and tnpA transposase. Four β-lactam, nine tetracycline, two phenicol, one trimethoprim, three aminoglycoside and ten multidrug resistance genes were detected as well as mcr-1 which confers resistance to colistin, an important drug of last resort. No sulphonamide, vancomycin, macrolide, lincosamide or streptogramin B (MLSB) resistance genes were detected. Resistance genes were detected in all sites but the highest number of ARGs (n = 29) was detected in samples derived from grey seals on the Isle of May, Scotland during the breeding season, and these genes also had the highest average abundance in relation to the 16S rRNA gene. This pilot study demonstrates the effectiveness of a culture-independent workflow for global analysis of ARGs within the microbiota of live, free-ranging, wild animals from habitats close to and remote from human habitation, and highlights seals as a valuable indicator species for monitoring the presence, abundance and land-sea transference of resistance genes within and between ecosystems.

Development of an orally bioavailable mSWI/SNF ATPase degrader and acquired mechanisms of resistance in prostate cancer

Mammalian switch/sucrose nonfermentable (mSWI/SNF) ATPase degraders have been shown to be effective in enhancer-driven cancers by functioning to impede oncogenic transcription factor chromatin accessibility. Here, we developed AU-24118, an orally bioavailable proteolysis-targeting chimera (PROTAC) degrader of mSWI/SNF ATPases (SMARCA2 and SMARCA4) and PBRM1. AU-24118 demonstrated tumor regression in a model of castration-resistant prostate cancer (CRPC) which was further enhanced with combination enzalutamide treatment, a standard of care androgen receptor (AR) antagonist used in CRPC patients. Importantly, AU-24118 exhibited favorable pharmacokinetic profiles in preclinical analyses in mice and rats, and further toxicity testing in mice showed a favorable safety profile. As acquired resistance is common with targeted cancer therapeutics, experiments were designed to explore potential mechanisms of resistance that may arise with long-term mSWI/SNF ATPase PROTAC treatment. Prostate cancer cell lines exposed to long-term treatment with high doses of a mSWI/SNF ATPase degrader developed SMARCA4 bromodomain mutations and ABCB1 (ATP binding cassette subfamily B member 1) overexpression as acquired mechanisms of resistance. Intriguingly, while SMARCA4 mutations provided specific resistance to mSWI/SNF degraders, ABCB1 overexpression provided broader resistance to other potent PROTAC degraders targeting bromodomain-containing protein 4 and AR. The ABCB1 inhibitor, zosuquidar, reversed resistance to all three PROTAC degraders tested. Combined, these findings position mSWI/SNF degraders for clinical translation for patients with enhancer-driven cancers and define strategies to overcome resistance mechanisms that may arise.

Spatiotemporal variations in the occurrence of Campylobacter species in the Bloukrans and Swartkops rivers, Eastern Cape, South Africa

An increase in the incidence of Campylobacter species in rivers raises concerns on the safety of river water for humans who get exposed to river water. This study examines the spatiotemporal dynamics of Campylobacter species in the Bloukrans and Swartkops rivers, analysing patterns of its occurrence in relation to meteorological conditions, physicochemical parameters, seasons, and sampling sites. Physico-chemical parameters and meteorological conditions were measured during water sampling from various sites along the rivers over a year, while Polymerase Chain Reaction (PCR) was utilised to detect Campylobacter genus-specific genes and selected antibiotic-resistant genes. Campylobacter was detected in 66.67% (Bloukrans River) and 58.33% (Swartkops River). In the Bloukrans River, multi-drug resistance genes cmeA (20%), cmeB (65%), cmeC (10%), were detected while and tetO was detected at 70%. In the Swartkops River, the corresponding prevalence were 28%, 66.67%, 28.56%, and 76%. The study indicates that sampling season did not significantly impact Campylobacter prevalence. However, variation in Campylobacter occurrence exists among different sites along the rivers, reflecting the influence of site proximity to potential contamination sources. The study suggests that Campylobacter infection may be endemic in South Africa, with rivers serving as potential sources of exposure to humans, thereby contributing to the epidemiology of campylobacteriosis.

Influence of ABCB1 3435C>T Polymorphism on Methotrexate Safety in Patients with Psoriasis — A Secondary Publication

Background: Methotrexate is a highly effective systemic treatment for moderate to severe psoriasis, but drug toxicity may limit its use. Recent evidence suggests that it is necessary to take into account the individual characteristics of methotrexate pharmacokinetics, which are determined by the presence of polymorphisms of genes encoding methotrexate carrier proteins, to predict the risk of methotrexate-induced toxicity. Aim: The research aims to assess the associations of ABCB1 rs1045642 (3435C>T) polymorphism with methotrexate safety for patients with moderate and severe psoriasis. Methods: The study included 75 psoriasis patients treated with methotrexate with 21 days of follow-up duration. Data on adverse drug reactions (ADR) were collected using a clinically structured questionnaire, and complete and biochemical blood tests, and urinalysis were performed. The severity of ADR was assessed using visual analog scales and the CTCAE toxicity scale. The severity of gastrointestinal ADR was assessed using the GSRS questionnaire. Genotyping was carried out by real-time PCR. Results: Gastrointestinal toxicity was detected in 38 patients (50.67%). The mean GSRS score was 7.97 ± 9.18. Analysis of differences in the ADR incidence showed the presence of statistically significant differences in the frequency of ADR in the gastrointestinal tract: the toxic effect of methotrexate was more often observed in carriers of the T allele of the ABCB1 rs1045642 polymorphism (3435C>T), (CC: 2 (14.3%), TC: 18 (52.9%), TT: 18 (66.7%), P = 0.006). Binomial regression demonstrated the presence of a statistically significant effect of the rs1045642 single-nucleotide polymorphism of the ABCB1 gene on the incidence of ADR from the gastrointestinal tract (OR = 8.64, P = 0.008). Conclusion: An association of ABCB1 rs1045642 single-nucleotide polymorphism with the safety of methotrexate therapy in patients with moderate and severe psoriasis was revealed. The data obtained can be used to personalize the prescription of methotrexate to psoriasis patients.

Antibiotic resistome in landfill leachate and impact on groundwater

Landfill leachate is a hotspot in antibiotic resistance development. However, little is known about antibiotic resistome and host pathogens in leachate and their effects on surrounding groundwater. Here, metagenomic sequencing was used to explore profiles, host bacteria, environmental risks and influencing factors of antibiotic resistome in raw and treated leachate and surrounding groundwater of three landfills. Results showed detection of a total of 324 antibiotic resistance genes (ARGs). The ARGs conferring resistance to multidrug (8.8 %–25.7 %), aminoglycoside (13.1 %–39.2 %), sulfonamide (10.0 %–20.9 %), tetracycline (5.7 %–34.4 %) and macrolide-lincosamide-streptogramin (MLS, 5.3 %–29.5 %) were dominant in raw leachate, while multidrug resistance genes were the major ARGs in treated leachate (64.1 %–83.0 %) and groundwater (28.7 %–76.6 %). Source tracking analysis suggests non-negligible influence of leachate on the ARGs in groundwater. The pathogens including Acinetobacter pittii, Pseudomonas stutzeri and P. alcaligenes were the major ARG-carrying hosts. Variance partitioning analysis indicates that the microbial community, abiotic variables and their interaction contributed most to the antibiotic resistance development. Our results shed light on the dissemination and driving mechanisms of ARGs from leachate to the groundwater, indicating that a comprehensive risk assessment and efficient treatment approaches are needed to deal with ARGs in landfill leachate and nearby groundwater. Environmental implicationsAntibiotic resistance genes are found abundant in the landfill sites, and these genes could be disseminated into groundwater via leaching of wastewater and infiltration of leachate. This results in deterioration of groundwater quality and human health risks posed by these ARGs and related pathogens. Thus measures should be taken to minimize potential negative impacts of landfills on the surrounding environment.

Personalized approach to outpatient management of patients taking tamoxifen by gynecologists

BACKGROUND: 30% of women with luminal breast cancer receiving adjuvant tamoxifen experience disease recurrence within 15 years. This demonstrates the wide variability in clinical response to tamoxifen. Both nongenetic (age, gender, body mass index, duration of drug use) and genetic factors have been described to influence the high variability of response to tamoxifen. Differences in the genes encoding the enzymes CYP2D6, CYP2C, and CYP3A (CYP2D6*4, CYP3A5*3, CYP2C9*2, CYP2C9*3, CYP2C19*2, CYP2C19*3) and the ABCB1 gene (C3435T) may also be the main factors of susceptibility to the occurrence of undesirable effects when taking tamoxifen, which in turn may lead to decreased patient adherence to therapy.
 AIM: The aim of this study was to create a concept and an algorithm for a personalized approach to outpatient management of patients taking tamoxifen by a gynecologist in connection with the carriage of polymorphisms of cytochrome P450 and drug transporter genes.
 MATERIALS AND METHODS: In 2017–2018, the outpatient records of 230 patients with breast cancer were analyzed retrospectively. A single-stage pharmacogenetic study of 120 women with stage I–III luminal breast cancer taking tamoxifen was conducted prospectively for the presence of cytochrome P450 gene polymorphisms using the polymerase chain reaction method and assessing associations with adverse drug reactions, and 54 patients were interviewed after five-year follow-up to assess adherence and satisfaction with medical supervision.
 RESULTS: The likelihood of developing endometrial hyperplasia has been shown to increase while taking tamoxifen with increasing average age, body mass index, duration of tamoxifen use, and postmenopause. Significant associations have been identified between the carriage of the CYP2D6, CYP2C9, CYP2C19, CYP3A5, and ABCB1 gene polymorphisms and the development of adverse drug reactions. Predictive models have been developed to determine the risk of adverse drug reactions. All studied adverse drug reactions associated with various genetic polymorphisms predominated in the group of patients who stopped taking tamoxifen due to poor intolerance. Gynecologists regularly observed 57.4% of patients. Moreover, the higher the adherence to therapy was, the higher was the regularity of observation by a gynecologist.
 CONCLUSIONS: A plan for outpatient management of patients receiving adjuvant endocrine therapy with tamoxifen by a gynecologist has been developed.

Glyphosate and aminomethylphosphonic acid metabolite (AMPA) modulate the phenotype of murine melanoma B16-F1 cells

Pesticides are contaminants run-offs from agricultural areas with a global concern due to their toxicity for non-target organisms. The Brazilian Health Surveillance Agency reported about 63% of the food contain pesticide residues. Glyphosate is a herbicide used worldwide but its toxicity is not a consensus among specialists around the world. AMPA (aminomethylphosphonic acid) is a glyphosate metabolite that can be more toxic than the parental molecule. Melanoma murine B16-F1 cells were exposed to glyphosate and AMPA to investigate the cell profile and possible induction to a more malignant phenotype. Glyphosate modulated the multi-drug resistance mechanisms by ABCB5 gene expression, decreasing cell attachment, increasing cell migration and inducing extracellular vesicles production, and the cells exposed to AMPA revealed potential damages to DNA. The present study observed that AMPA exhibits high cytotoxicity, which suggests a potential impact on non-tumor cells, which are, in general, more susceptible to chemical exposure. Conversely, glyphosate favored a more metastatic and chemoresistant behavior in cancer cells, highlighting the importance of additional research in this area.

Pharmacogenetic Approaches in Personalized Medicine for Postoperative Pain Management.

Despite technical and pharmacological advancements in recent years, including optimized therapies and personalized medicine, postoperative pain management remains challenging and sometimes undertreated. This review aims to summarize and update how genotype-guided therapeutics within personalized medicine can enhance postoperative pain management. Several studies in the area have demonstrated that genotype-guided therapy has the ability to lower opioid consumption and improve postoperative pain. Gene mutations, primarily OPRM1, CYP2D6, CYP2C9, COMT and ABCB1, have been shown to exert nuanced influences on analgesic response and related pharmacological outcomes. This review underscores the integration of pharmacogenetic-guided personalized medicine into perioperative care, particularly when there is uncertainty regarding opioid prescriptions. This approach leads to superior outcomes in terms of postoperative pain relief and reduced morbidity for numerous patients.

Abstract 1998: ABCB1 promotes uveal melanoma cell resistance to FR900359 and identifies a tumor cell subpopulation with a distinct gene expression signature

Abstract Uveal melanoma (UM) is the leading form of intraocular cancer in adults and the second most common form of melanoma. Although rare, UM has a median survival rate of ~1 year after metastasis occurs. Metastatic UM is largely refractory to treatment and there are no effective pharmacological therapies, resulting in poor overall survival. In >90% UM cases, the oncogenic initiator proteins are constitutively active mutant GNAQ or GNA11 proteins (GNAQ/11). FR900359 (FR) is a natural compound that inhibits GNAQ/11 and has anti-proliferative effects on UM cells. To identify key oncogenic mechanisms downstream of mutant GNAQ/11, we performed a Sleeping Beauty (SB) transposon forward genetic screen to identify drivers of FR resistance. The SB screen identified ATP-binding cassette sub-family B member 1 (ABCB1) as one of the top genes upregulated by SB in FR-resistant UM cell populations. We determined that although ABCB1 does not provide immediate resistance to FR, the overexpression of ABCB1 leads to emergence of resistant colonies at a much higher rate than spontaneous resistance, validating ABCB1 as contributors to FR resistance. Unexpectedly, immunofluorescence revealed that a relatively small fraction of UM cells strongly expresses the transgenes after stable transfection. Immunoblotting confirmed that ABCB1 expression was initially modest in ABCB1-transfected populations but increased in the cells that developed resistance to FR. To examine the kinetics of FR resistance, population doubling versus time (PDVT) assays were performed in UM cells expressing ABCB1 or empty vector control treated with FR or vehicle. FR potently suppressed the proliferation of vector control cells. Drug-naïve ABCB1-transfected cells developed resistance to FR over time but accomplished fewer population doublings than vehicle-treated cells in the same time interval. Once transgenic populations emerged as resistant populations in FR, they grew similarly in drug or vehicle. Ongoing RNA-sequencing analysis from PDVT samples has identified distinct gene expression signatures associated with FR treatment and ABCB1 expression. These findings are expected to illuminate tumor cell heterogeneity amongst UM cell populations that may be related to drug resistance and metastasis. Citation Format: Sarina Dion Murray, Jesse D. Riordan, Eric R. Anderson, Michael D. Onken, Kendall J. Blumer, Adam J. Dupuy, Christopher S. Stipp. ABCB1 promotes uveal melanoma cell resistance to FR900359 and identifies a tumor cell subpopulation with a distinct gene expression signature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1998.