ABCC2 induces metabolic vulnerability and cellular ferroptosis via enhanced glutathione efflux in gastric cancer.

BACKGROUND: Although it is traditionally believed that ATP binding cassette subfamily C member 2 (ABCC2) is a multidrug resistance-associated protein correlated with a worse prognosis, our previous and several other studies demonstrated the contrary to be true in gastric cancer (GC). We aim to explore the underlying mechanism of this discovery. METHODS: Our study utilized whole-exome sequencing (WES), RNA sequencing, and droplet digital PCR (ddPCR) analysis of 80 gastric cancer samples, along with comprehensive immunohistochemical (IHC) analysis of 1044 human GC tissue samples.By utilizing CRISPRCas9 to genetically modify cell lines with the ABCC2-24C > T (rs717620) point mutation and conducting dual-luciferase reporter assays, we identified that transcription factors SOX9 and ETS1 serve as negative regulators of ABCC2 expression. Seahorse assay and mass spectrometry were used to discover altered metabolic patterns. Gain and loss-of-function experiments in GC cell lines and preclinical models were carried out to validate ABCC2 biological function. RESULTS: ABCC2 high expression correlated with better prognosis, and rs717620 can influence ABCC2 expression by disrupting the binding of ETS1 and SOX9. Gain and loss-of-function experiments in GC cell lines demonstrated amino acid deprivation reduces proliferation, migration, and drug resistance in ABCC2-high GC cells. ABCC2 leads to reduced intracellular amino acid pools and disruption of cellular energy metabolism. This phenomenon depended on ABCC2-mediated GSH extrusion, resulting in alterations in redox status, thereby increasing the cell's susceptibility to ferroptosis. Furthermore, patient-derived organoids and patient-derived tumor-like cell clusters were used to observe impact of ABCC2 on therapeutic effect. In the xenograft model with high ABCC2 expression, we observed that constricting amino acid intake in conjunction with GPX4 inactivation resulted in notable tumor regression. CONCLUSIONS: Our findings demonstrate a significant role of ABCC2 in amino acid metabolism and ferroptosis by mediating GSH efflux in GC. This discovery underlines the potential of combining multiple ferroptosis targets as a promising therapeutic strategy for GC with high ABCC2 expression. HIGHLIGHTS: ABCC2 plays a crucial role in inducing metabolic vulnerability and ferroptosis in gastric cancer through enhanced glutathione efflux. The ABCC2 24C > T polymorphism is a key factor influencing its expression. These results highlight the potential of ABCC2 as a predictive biomarker and therapeutic target in gastric cancer.

Case Report: A case of Dubin-Johnson syndrome in a newborn.

Background: Dubin-Johnson Syndrome (DJS) is a rare autosomal recessive genetic disorder, with most cases presenting in adolescence, but rare in newborns. Objective: To investigate the clinical characteristics and treatment outcomes of DJS in a newborn. Methods: We present the clinical features of a newborn diagnosed with DJS through molecular genetic testing. Results: The patient was a male newborn who developed jaundice and scleral icterus on the 6th day of life. Both direct and indirect bilirubin levels were elevated. After treatment with phototherapy, indirect bilirubin levels decreased, but direct bilirubin remained unchanged, and the stool color gradually lightened. At 56 days of age, the patient underwent laparoscopic cholecystostomy, which revealed viscous bile plugs in the bile ducts. Following the surgery, the patient received oral ursodeoxycholic acid, compound glycyrrhizin, and methylprednisolone. Follow-up until one year post-surgery showed a gradual reduction in direct bilirubin levels to the normal range. Molecular genetic testing revealed three heterozygous mutations in the ABCC2 gene on chromosome 10, with one pathogenic variant inherited from the father and two from the mother, confirming the diagnosis of DJS. Conclusion: DJS is a benign condition with a favorable prognosis. In newborns, it should be differentiated from other causes of cholestasis, and compared to cholestasis, jaundice in newborns with DJS responds more slowly to treatment.

In silico and biological analyses of missense variants of the human biliary efflux transporter ABCC2: effects of novel rare missense variants.

BACKGROUND AND PURPOSE: The ATP-dependent biliary efflux transporter ABCC2, also known as multidrug resistance protein 2 (MRP2), is essential for the cellular disposition and detoxification of various xenobiotics including drugs as well as endogenous metabolites. Common functionally relevant ABCC2 genetic variants significantly alter drug responses and contribute to side effects. The aim of this study was to determine functional consequences of rare variants identified in subjects with European ancestry using in silico tools and in vitro analyses. EXPERIMENTAL APPROACH: Targeted next-generation sequencing of the ABCC2 gene was used to identify novel variants in European subjects (n = 143). Twenty-six in silico tools were used to predict functional consequences. For biological validation, transport assays were carried out with membrane vesicles prepared from cell lines overexpressing the newly identified ABCC2 variants and estradiol ß-glucuronide and carboxydichlorofluorescein as the substrates. KEY RESULTS: Three novel rare ABCC2 missense variants were identified (W227R, K402T, V489F). Twenty-five in silico tools predicted W227R as damaging and one as potentially damaging. Prediction of functional consequences was not possible for K402T and V489F and for the common linked variants V1188E/C1515Y. Characterisation in vitro showed increased function of W227R, V489F and V1188E/C1515Y for both substrates, whereas K402T function was only increased for carboxydichlorofluorescein. CONCLUSION AND IMPLICATIONS: In silico tools were unable to accurately predict the substrate-dependent increase in function of ABCC2 missense variants. In vitro biological studies are required to accurately determine functional activity to avoid misleading consequences for drug therapy.

Contemporary review of papillary renal cell carcinoma-current state and future directions.

Historically, papillary renal cell carcinoma (PRCC) was divided into two types, type 1 and type 2, based solely on morphology. However, it is apparent that PRCC is far more complex and represents a histological, clinical, and molecular spectrum. There has been a significant evolution in our understanding of PRCC, highlighted by the recognition of new and molecularly defined entities that were previously included in PRCC type 2. This contemporary review addresses the evolving concepts regarding the PRCC, including why it is no longer needed to subtype PRCC, the current molecular landscape, prognostic parameters, and PRCC variants, including biphasic PRCC, papillary renal neoplasm with reverse polarity, and Warthin-like PRCC. Pathologists should also be aware of the potential mimickers of both low-grade and high-grade PRCCs as well as some new and emerging entities that may show papillary growth that should be excluded in the diagnostic workup. The evolving knowledge of PRCC biomarkers, morphologic patterns, and PRCC variants could also have important implications for clinical management. Lastly, the heterogeneity within the PRCC spectrum needs to be further studied, aiming to better stratify PRCC for appropriate clinical management and systemic therapy.

Distinguishing Molecular Properties of OAT, OATP, and MRP Drug Substrates by Machine Learning.

The movement of organic anionic drugs across cell membranes is partly governed by interactions with SLC and ABC transporters in the intestine, liver, kidney, blood-brain barrier, placenta, breast, and other tissues. Major transporters involved include organic anion transporters (OATs, SLC22 family), organic anion transporting polypeptides (OATPs, SLCO family), and multidrug resistance proteins (MRPs, ABCC family). However, the sets of molecular properties of drugs that are necessary for interactions with OATs (OAT1, OAT3) vs. OATPs (OATP1B1, OATP1B3) vs. MRPs (MRP2, MRP4) are not well-understood. Defining these molecular properties is necessary for a better understanding of drug and metabolite handling across the gut-liver-kidney axis, gut-brain axis, and other multi-organ axes. It is also useful for tissue targeting of small molecule drugs and predicting drug-drug interactions and drug-metabolite interactions. Here, we curated a database of drugs shown to interact with these transporters in vitro and used chemoinformatic approaches to describe their molecular properties. We then sought to define sets of molecular properties that distinguish drugs interacting with OATs, OATPs, and MRPs in binary classifications using machine learning and artificial intelligence approaches. We identified sets of key molecular properties (e.g., rotatable bond count, lipophilicity, number of ringed structures) for classifying OATs vs. MRPs and OATs vs. OATPs. However, sets of molecular properties differentiating OATP vs. MRP substrates were less evident, as drugs interacting with MRP2 and MRP4 do not form a tight group owing to differing hydrophobicity and molecular complexity for interactions with the two transporters. If the results also hold for endogenous metabolites, they may deepen our knowledge of organ crosstalk, as described in the Remote Sensing and Signaling Theory. The results also provide a molecular basis for understanding how small organic molecules differentially interact with OATs, OATPs, and MRPs.

The Impact of ABCC2 -24C>T Gene Polymorphism on Graft Survival in Kidney Transplant Recipients.

Personalized medicine in kidney transplantation has the potential to improve outcomes and reduce complications. The aim of this study was to investigate the influence of single nucleotide polymorphisms in genes encoding metabolizing enzymes (CYP3A5) and transporters (ABCC2) on clinical outcomes (acute graft failure and/or acute tubular necrosis (ATN)) in kidney transplant recipients (KTR). This was a multicenter, retrospective cohort study where adult KTR who had undergone kidney transplantation between 2020 and 2021 and received tacrolimus-mycophenolate treatment were enrolled in the study. DNA was extracted from collected blood samples using a commercially available kit. CYP3A5*3, ABCC2 -24C>T and ABCC2 3972C>T SNP were determined by polymerase chain reaction. Of the total 39 patients included, nine (23.1%) KTR had an incidence of acute graft failure and/or ATN. A multiple logistic regression showed wildtype ABCC2 -24C>T C allele had a higher risk of developing acute graft rejection and/or ATN compared to the variant allele carriers (adjusted Odd Ratios [aOR]: 27.675, p = 0.038). Recipients who had delayed graft function (aOR: 49.214, p = 0.012) and a history of CMV infection (aOR: 18.097, p = 0.009) were at 49.2 and 18.1-times increased risk for acute graft failure and/or ATN, respectively. The large aOR was inevitable due to the small sample size and required cautious interpretation. This is the first study to determine the effect of the ABCC2 -24C>T genetic polymorphism on clinical outcomes in Malaysian KTR and forms the basis for further work on ABCC2 -24C>T effects in long-term KTR.

Throwing Brazilian strains into the melting pot of P. xylostella resistance to Bacillus thuringiensis.

The resistance of pest insects to biopesticides based on the bacterium Bacillus thuringiensis (Bt) is normally associated with changes to the receptors involved in the mechanism of action of the pesticidal proteins produced by Bt. In some strains of Plutella xylostella (the diamondback moth) resistance has evolved through a signalling mechanism in which the genes encoding the receptor proteins are downregulated whereas in others it has been linked to structural changes in the receptors themselves. One such well characterized mutation is in the ABCC2 gene indicating that changes to this protein can result in resistance. However other studies have found that knocking out this protein does not result in a significant level of resistance. In this study we wanted to test the hypothesis that constitutive receptor downregulation is the major cause of Bt resistance in P. xylostella and that mutations in the now poorly expressed receptor genes may not contribute significantly to the phenotype. To that end we investigated the expression of a receptor (ABCC2) and the major regulator of the signalling pathway (MAP4K4) in two resistant and four susceptible strains. No correlation was found between expression levels and susceptibility; however, a frameshift mutation was identified in the ABCC2 receptor in a newly characterized resistant strain.

Extracellular Vesicles as Surrogates for the Regulation of the Drug Transporters ABCC2 (MRP2) and ABCG2 (BCRP).

Drug efflux transporters of the ATP-binding-cassette superfamily play a major role in the availability and concentration of drugs at their site of action. ABCC2 (MRP2) and ABCG2 (BCRP) are among the most important drug transporters that determine the pharmacokinetics of many drugs and whose overexpression is associated with cancer chemoresistance. ABCC2 and ABCG2 expression is frequently altered during treatment, thus influencing efficacy and toxicity. Currently, there are no routine approaches available to closely monitor transporter expression. Here, we developed and validated a UPLC-MS/MS method to quantify ABCC2 and ABCG2 in extracellular vesicles (EVs) from cell culture and plasma. In this way, an association between ABCC2 protein levels and transporter activity in HepG2 cells treated with rifampicin and hypericin and their derived EVs was observed. Although ABCG2 was detected in MCF7 cell-derived EVs, the transporter levels in the vesicles did not reflect the expression in the cells. An analysis of plasma EVs from healthy volunteers confirmed, for the first time at the protein level, the presence of both transporters in more than half of the samples. Our findings support the potential of analyzing ABC transporters, and especially ABCC2, in EVs to estimate the transporter expression in HepG2 cells.

Papillary renal neoplasm with reverse polarity is biologically and clinically distinct from eosinophilic papillary renal cell carcinoma.

Papillary renal neoplasm with reverse polarity (PRNRP) is a recently described indolent entity with distinct features and its recognition from other oncocytic/eosinophilic papillary renal cell carcinoma (ePRCC) has important prognostic implications. ABCC2, a renal drug transporter, is overexpressed in aggressive PRCCs. In this study, we compared the clinicopathological parameters and the biological ABCC2 expression between PRNRP and ePRCC. PRNRP (n = 8) and ePRCC (n = 21) cases were selected from resection specimens and corresponding clinicopathological data were collected. ABCC2 immunohistochemical (IHC) staining was performed and ABCC2 staining patterns were classified as negative, cytoplasmic, and brush-border. RNA in-situ hybridization (ISH) was used to assess ABCC2 transcript levels. All eight PRNRP cases had weak cytoplasmic ABCC2 IHC reactivity; however, they showed no detectable ABCC2 transcripts on RNA ISH. In comparison, 76% (16/21) of ePRCCs showed ABCC2 IHC brush-border expression and significantly higher ABCC2 RNA ISH transcript levels (p < 0.001). Additionally, the ePRCC group showed a significantly larger tumor size (p = 0.004), higher WHO/ISUP grade (p < 0.001), and stage (p = 0.044). None of the PRNRP cases showed disease progression, while 9.5% (2/21) ePRCCs had disease progression. PRNRP is clinically and biologically distinct from ePRCC. Hence, it is crucial to differentiate between these two entities, particularly in needle core biopsies.

Mutation in PgABCC2 confers low-level resistance to Cry1Ac in pink bollworm.

BACKGROUND: With the increasing incidence of pest resistance to transgenic crops producing Bacillus thuringiensis (Bt) proteins in the field, elucidating the molecular basis of resistance is important for monitoring, delaying and countering pest resistance. Previous work revealed that mutation or down-regulated expression of the cadherin gene (PgCad1) is associated with pink bollworm (Pectinophora gossypiella) resistance to Cry1Ac, and 20 mutant PgCad1 alleles (r1-r20) were characterized. Here, we tested the hypothesis that the ABC transporter PgABCC2 is a functional receptor for the Bt toxin Cry1Ac and that a mutation is associated with resistance. RESULTS: We identified and characterized the first resistance allele (rC2) of PgABCC2 in the laboratory-selected Cry1Ac-resistant strain AQ-C2 of pink bollworm. The rC2 allele had a one-base deletion in exon20, resulting in a frameshift and the introduction of a premature stop codon. This resulting PgABCC2 protein had a truncated C-terminus, including the loss of the NBD2 domain. AQ-C2 exhibited 20.2-fold greater resistance to Cry1Ac than the susceptible strain, and its inheritance of Cry1Ac resistance was recessive and genetically linked to PgABCC2. When produced in cultured insect cells, recombinant wild-type and rC2 mutant PgABCC2 proteins localized within the cell plasma membrane, although substantial cytoplasmic retention was also observed for the mutant protein, while the mutant PgABCC2 caused a 13.9-fold decrease in Cry1Ac toxicity versus the wild-type PgABCC2. CONCLUSIONS: PgABCC2 is a functional receptor of Cry1Ac and the loss of its carboxyl terminus (including its NBD2 domain) confers low-level resistance to Cry1Ac in both larvae and in cultured cells. © 2024 Society of Chemical Industry.

A Six-gene Prognostic Model Based on Neutrophil Extracellular Traps (NETs)-related Gene Signature for Lung Adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is one of the most common malignant cancers. Neutrophil extracellular traps (NETs) have been discovered to play a crucial role in the pathogenesis of LUAD. We aimed to establish an innovative prognostic model for LUAD based on the distinct expression patterns of NETs-related genes. METHODS: The TCGA LUAD dataset was utilized as the training set, while GSE31210, GSE37745, and GSE50081 were undertaken as the verification sets. The patients were grouped into clusters based on the expression signature of NETs-related genes. Differentially expressed genes between clusters were identified through the utilization of the random forest and LASSO algorithms. The NETs score model for LUAD prognosis was developed by multiplying the expression levels of specific genes with their corresponding LASSO coefficients and then summing them. The validity of the model was confirmed by analysis of the survival curves and ROC curves. Additionally, immune infiltration, GSEA, mutation analysis, and drug analysis were conducted. Silencing ABCC2 in A549 cells was achieved to investigate its effect. RESULTS: We identified six novel NETs-related genes, namely UPK1B, SFTA3, GGTLC1, SCGB3A1, ABCC2, and NTS, and developed a NETs score signature, which exhibited a significant correlation with the clinicopathological and immune traits of the LUAD patients. High-risk patients showed inhibition of immune-related processes. Mutation patterns exhibited variability among the different groups. AZD3759, lapatinib, and dasatinib have been identified as potential candidates for LUAD treatment. Moreover, the downregulation of ABCC2 resulted in the induction of apoptosis and suppression of migration and invasion in A549 cells. CONCLUSION: Altogether, this study has identified a novel NET-score signature based on six novel NET-related genes to predict the prognosis of LUAD and ABCC2 and has also explored a new method for personalized chemo-/immuno-therapy of LUAD.

Integrative analysis of rs717620 polymorphism in therapeutic response to anti-seizure medications.

Background: Previous studies have shown that the rs717620 polymorphism in ABCC2, the gene encoding multidrug resistance protein 2, influences the therapeutic response to anti-seizure medications (ASMs). However, this result is not consistent, and the mechanism by which rs717620 influences ASM responses is unclear. Aims: The present study evaluated the association between rs717620 genotype and ASM efficacy, and examined the potential mechanisms. Main: methods: We conducted a literature search of five electronic databases, Embase, Medline, Web of Science, China National Knowledge Infrastructure, and Wanfang, to identify relevant studies on response to ASM therapy among rs717620 genotypes. Expression quantitative trait loci analysis and drug-gene interaction analysis were also performed to assess the underlying mechanisms. Key findings: The pooled results for 18 studies revealed a significant association between rs717620 genotype and ASM resistance under the recessive model (TT vs. CT + CC: OR = 1.68, 95 % CI = 1.27-2.21, I2 = 3.1 %). A significant association was also found in the Asian population under the recessive model (TT vs. CT + CC: OR = 1.70, 95 % CI = 1.26-2.29, I2 = 29.3 %). Further analysis revealed that rs717620 regulates the expression of ABCC2 in human brain, while drug-gene interaction analysis suggested that ABCC2 interacts with oxcarbazepine and carbamazepine. Significance: The rs717620 polymorphism influences ASM therapeutic responses by altering brain expression levels of ABCC2.

Gene Expression of Abcc2 and Its Regulation by Chicken Xenobiotic Receptor.

Membrane transporter multidrug resistance-associated protein 2 (MRP2/Abcc2) exhibits high pharmaco-toxicological relevance because it exports multiple cytotoxic compounds from cells. However, no detailed information about the gene expression and regulation of MRP2 in chickens is yet available. Here, we sought to investigate the expression distribution of Abcc2 in different tissues of chicken and then determine whether Abcc2 expression is induced by chicken xenobiotic receptor (CXR). The bioinformatics analyses showed that MRP2 transporters have three transmembrane structural domains (MSDs) and two highly conserved nucleotide structural domains (NBDs), and a close evolutionary relationship with turkeys. Tissue distribution analysis indicated that Abcc2 was highly expressed in the liver, kidney, duodenum, and jejunum. When exposed to metyrapone (an agonist of CXR) and ketoconazole (an antagonist of CXR), Abcc2 expression was upregulated and downregulated correspondingly. We further confirmed that Abcc2 gene regulation is dependent on CXR, by overexpressing and interfering with CXR, respectively. We also demonstrated the induction of Abcc2 expression and the activity of ivermectin, with CXR being a likely mediator. Animal experiments demonstrated that metyrapone and ivermectin induced Abcc2 in the liver, kidney, and duodenum of chickens. Together, our study identified the gene expression of Abcc2 and its regulation by CXR in chickens, which may provide novel targets for the reasonable usage of veterinary drugs.

PFKP confers chemoresistance by upregulating ABCC2 transporter in non-small cell lung cancer.

Background: Chemoresistance is a significant factor contributing to tumor recurrence and treatment failure in non-small cell lung cancer (NSCLC). The phosphofructokinase, platelet (PFKP) is highly expressed in NSCLC and is associated with a poor prognosis. Exploring the molecular mechanism and identifying effective strategies to overcome chemoresistance will have important clinical significance in improving the diagnosis and treatment of NSCLC. Methods: The correlation between PFKP and cisplatin resistance in NSCLC patients was assessed by organoids and immunohistochemistry. The impact of PFKP on the prognosis of NSCLC patients was analyzed using The Cancer Genome Atlas (TCGA) database. In NSCLC cell lines, the expression of PFKP was modulated using lentivirus, and cisplatin sensitivity was assessed by flow cytometry. Subsequently, the therapeutic effect of cisplatin was tested in BALB/c nude mice implanted subcutaneously with tumor cells. We performed luciferase assay and immunohistochemistry (IHC) to investigate the correlation between PFKP and ABCC2 (ATP-binding cassette sub-family C member 2). Results: Overexpression of PFKP was correlated with poorer survival rates in NSCLC patients who received platinum-based chemotherapy. Using NSCLC organoid, we found that the expression of PFKP was elevated in cisplatin (CDDP)-resistant patients with NSCLC. Overexpression of PFKP decreased the sensitivity of NSCLC cells to CDDP, while genetic inhibition of PFKP enhanced CDDP sensitivity both in vitro and in vivo. Furthermore, we found that PFKP upregulated ABCC2 by increasing the levels of phosphorylation of IκBα and nuclear p65 NF-κB subunit protein. Conclusions: PFKP can regulate the expression of ABCC2 through the activation of NF-κB, which in turn promotes chemoresistance in NSCLC. PFKP has the potential to be a personalized therapeutic target for NSCLC patients with chemoresistance.

ABCC2 brush-border expression predicts outcome in papillary renal cell carcinoma: a multi-institutional study of 254 cases.

AIMS: Papillary renal cell carcinoma (PRCC) histologic subtyping is no longer recommended in the 2022 WHO classification. Currently, WHO/ISUP nucleolar grade is the only accepted prognostic histologic parameter for PRCC. ABCC2, a renal drug transporter, has been shown to significantly predict outcomes in PRCC. In this study we evaluated the prognostic significance of ABCC2 IHC staining patterns in a large, multi-institutional PRCC cohort and assessed the association of these patterns with ABCC2 mRNA expression. METHODS AND RESULTS: We assessed 254 PRCCs for ABCC2 IHC reactivity patterns that were stratified into negative, cytoplasmic, brush-border <50%, and brush-border ≥50%. RNA in situ hybridization (ISH) was used to determine the transcript level of each group. Survival analysis was performed with SPSS and GraphPad software. RNA-ISH showed that the ABCC2 group with any brush-border staining was associated with a significant increase in the transcript level, when compared to the negative/cytoplasmic group (P = 0.034). Both ABCC2 groups with brush-border <50% (P = 0.024) and brush-border ≥50% (P < 0.001) were also associated with worse disease-free survival (DFS) in univariate analysis. Multivariate analysis showed that only ABCC2 IHC brush-border (<50% and ≥50%) reactivity groups (P = 0.037 and P = 0.003, respectively), and high-stage disease (P < 0.001) had a DFS of prognostic significance. In addition, ABCC2 brush-border showed significantly worse DFS in pT1a (P = 0.014), pT1 (P = 0.013), ≤4 cm tumour (P = 0.041) and high stage (P = 0.014) groups, while a similar analysis with high WHO/ISUP grade in these groups was not significant. CONCLUSION: ABCC2 IHC brush-border expression in PRCC correlates with significantly higher gene expression and also independently predicts survival outcomes.

Overexpression of MRP1/ABCC1, Survivin and BCRP/ABCC2 Predicts the Resistance of Diffuse Large B-Cell Lymphoma to R-CHOP Treatment.

BACKGROUND: Approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL) experience treatment resistance to the first-line R-CHOP regimen. ATP binding cassette (ABC) transporters and survivin might play a role in multidrug resistance (MDR) in various tumors. The aim was to investigate if the coexpression of ABC transporters and survivin was associated with R-CHOP treatment response. METHODS: The expression of Bcl-2, survivin, P-glycoprotein/ABCB1, MRP1/ABCC1, and BCRP/ABCC2 was analyzed using immunohistochemistry in tumor specimens obtained from patients with DLBCL, and classified according to the treatment response as Remission, Relapsed, and (primary) Refractory groups. All patients received R-CHOP or equivalent treatment. RESULTS: Bcl-2 was in strong positive correlation with clinical parameters and all biomarkers except P-gp/ABCB1. The overexpression of MRP1/ABCC1, survivin, and BCRP/ABCC2 presented as high immunoreactive scores (IRSs) was detected in the Refractory and Relapsed groups (p < 0.05 vs. Remission), respectively, whereas the IRS of P-gp/ABCB1 was low. Significant correlations were found among either MRP1/ABCC1 and survivin or BCRP/ABCC2 in the Refractory and Relapsed groups, respectively. In multiple linear regression analysis, ECOG status along with MRP1/ABCC1 or survivin and BRCP/ABCG2 was significantly associated with the prediction of the R-CHOP treatment response. CONCLUSIONS: DLBCL might harbor certain molecular signatures such as MRP1/ABCC1, survivin, and BCRP/ABCC2 overexpression that can predict resistance to R-CHOP.

Helicoverpa armigera GATAe transcriptional factor regulates the expression of Bacillus thuringiensis Cry1Ac receptor gene ABCC2 by its interplay with additional transcription factors.

Helicoverpa armigera is a worldwide pest that has been efficiently controlled by transgenic plants expressing Bt Cry toxins. To exert toxicity, Cry toxins bind to different receptors located in larval midgut cells. Previously, we reported that GATA transcription factor GATAe activates the expression of multiple H. armigera Cry1Ac receptors in different insect cell lines. Here, the mechanism involved in GATAe regulation of HaABCC2 gene expression, a key receptor of Cry1Ac, was analyzed. HaGATAe gene silencing by RNAi in H. armigera larvae confirmed the activation role of HaGATAe on the expression of HaABCC2 in the midgut. The contribution of all potential GATAe-binding sites was analyzed by site-directed mutagenesis using Hi5 cells expressing a reporter gene under regulation of different modified HaABCC2 promoters. DNA pull-down assays revealed that GATAe bound to different predicted GATA-binding sites and mutations of the different GATAe-binding sites identified two binding sites responsible for the promoter activity. The binding site B9, which is located near the transcription initiator site, has a major contribution on HaABCC2 expression. Also, DNA pull-down assays revealed that all other members of GATA TF family in H. armigera, besides GATAe, HaGATAa, HaGATAb, HaGATAc and HaGATAd also bound to the HaABCC2 promoter and decreased the GATAe dependent promoter activity. Finally, the potential participation in the regulation of HaABCC2 promoter of several TFs other than GATA TFs expressed in the midgut cells was analyzed. HaHR3 inhibited the GATAe dependent activity of the HaABCC2 promoter, while two other midgut-related TFs, HaCDX and HaSox21, also bound to the HaABCC2 promoter region and increased the GATAe dependent promoter activity. All these data showed that GATAe induces HaABCC2 expression by binding to HaGATAe binding sites in the promoter region and that additional TFs participate in modulating the HaGATAe-driven expression of HaABCC2.

Excessive vincristine exposure in a child being treated for acute lymphoblastic leukaemia with underlying Dubin-Johnson syndrome: a case report.

BACKGROUND: Dubin-Johnson syndrome is a rare benign autosomal recessive condition that causes an isolated increase of conjugated bilirubin in the serum. Impaired biliary excretion is due to mutation in the multiple drug-resistance protein 2 gene (MRP2). CASE PRESENTATION: We describe the case of a 4-year-old girl being treated for acute lymphoblastic leukaemia who had a history of conjugated hyperbilirubinaemia and persistently elevated bilirubin levels on initiation of chemotherapy. During treatment for leukaemia, she was diagnosed with Dubin-Johnson syndrome for the underlying condition. Following administration of vincristine at the recommended dose of 1.5 mg/m2, an abnormally high vincristine exposure was observed (AUC > 200 µg/L*h), approximately 3 times higher than previously reported exposures in a comparable clinical setting. Vincristine dose reductions were applied on subsequent cycles of treatment and resulted in markedly reduced drug exposures, within the normal target range. CONCLUSION: This case provided a rare opportunity to assess the impact of MRP2 mutations associated with Dubin-Johnson syndrome on the pharmacokinetics of vincristine and strongly indicates that a marked dose reduction should be recommended. Clinicians should be made aware of the potential for altered drug disposition for agents such as vincristine in patients with this rare genetic condition.

Bixin and Fuxoxanthin Alone and in Combination with Cisplatin Regulate ABCC1 and ABCC2 Transcription in A549 Lung Cancer Cells.

Background: The ATP-Binding Cassette (ABC) transporter has long been studied to confer drug resistance in human tumors and play important role in metabolic processes and cellular signaling. The overexpression of ABCB1, ABCC1, ABCC2, ABCC3, and ABCG2 leads to decreased sensitivity of lung cancer to cisplatin. At the transcription level, the expression of ABC transporters is highly regulated and requires the complex interplay of factors involved in differentiation and development, cell survival and apoptosis upon intrinsic and environmental stress. The p53 regulation of drug-resistance genes is also complex yet not well understood. Previously, we demonstrated the synergistic interaction between bixin or fucoxanthin with cisplatin in A549 lung cancer cells. Objectives: Current study aims to identify whether carotenoids enhancing therapeutic effect of Cisplatin due to the ability to reverse drug resistance associated proteins, such as ABC transporter and regulating the tumor suppressor corresponding gene, p53. Methods: Real-Time Quantitative-Polymerase Chain Reaction (RT-qPCR) was performed to estimate the expression level of ABCC1 and ABCC2, and p53 of A549 cell lines in response to carotenoids alone and in combination with cisplatin. Results and Conclusion: The administration of bixin or fucoxanthin decreases the expression of ABCC1 and ABCC2. Both carotenoids, either alone or in combination with cisplatin, upregulated p53 gene expression indicating the mechanism of proliferation inhibition and apoptosis occurs via the p53 caspase-independent pathway.

Urinary coproporphyrins as a diagnostic biomarker of Dubin-Johnson syndrome in neonates: A diagnostic pathway is proposed.

Background: Dubin-Johnson syndrome (DJS) presents during the neonatal period with a phenotype that overlaps with a broad list of causes of neonatal cholestasis (NC), which makes the identification of DJS challenging for clinicians. We conducted a case-controlled study to investigate the utility of urinary coproporphyrins (UCP) I% as a potential diagnostic biomarker. Methods: We reviewed our database of 533 cases of NC and identified 28 neonates with disease-causing variants in ATP-binding cassette-subfamily C member 2 (ABCC2) gene "Cases" (Study period 2008-2019). Another 20 neonates with cholestasis due to non-DJS diagnoses were included as "controls." Both groups underwent UCP analysis to measure CP isomer I percentage (%). Results: Serum alanine aminotransferase (ALT) levels were within the normal range in 26 patients (92%) and mildly elevated in 2 patients. ALT levels were significantly lower in neonates with DJS than in NC from other causes (P < 0.001). The use of normal serum ALT levels to predict DJS among neonates with cholestasis had a sensitivity of 93%, specificity 90%, positive predictive value (PPV) 34%, and negative predictive value (NPV) 99.5%. The median UCPI% was significantly higher in DJS patients [88%, interquartile range (IQR) 1-IQR3, 84.2%-92.7%] than in NC from other causes [67%, (IQR1-IQR3, 61%-71.5%; Confidence interval 0.18-0.28; P< 0.001)]. The use of UCPI% >80% to predict DJS had a sensitivity, specificity, PPV, and NPV of 100%. Conclusion: Based on the results from our study, we propose sequencing of the ABCC2 gene in neonates with normal ALT, presence of cholestasis and UCP1% >80%.