Multidrug resistance-associated protein 1 (MRP1/ABCC1) polymorphism: from discovery to clinical application

Circular RNA circ-CD44 regulates chemotherapy resistance by targeting the miR-330-5p/ABCC1 axis in colorectal cancer cells

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor worldwide, ranking fourth for incidence. Recently, circular RNAs (circRNAs) have been demonstrated to play a key role in chemotherapy resistance to CRC treatment. Therefore, the role of circ-CD44 is investigated in CRC.

METHODS

The expression levels of circ-CD44, miR-330-5p, and ATP binding cassette subfamily C member 1 (ABCC1) were quantified by real-time quantitative polymerase chain reaction (RT-qPCR) assay. The sensitivity of CRC cells to oxaliplatin (OXA) was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT) assay. Colony-forming experiment was performed to measure the colony-forming ability of CRC cells. The apoptosis, migration, and invasion of CRC cells were determined by flow cytometry and transwell assays. A xenograft experiment was established to clarify the functional role of circ-CD44 silencing in vivo. The interactional relationship among circ-CD44, miR-330-5p, and ABCC1 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. The protein expression of ABCC1 was quantified by western blot assay.

RESULTS

Circ-CD44 was obviously upregulated in OXA-resistant colorectal cancer tissues and cells. Loss-of-function experiments revealed that inhibition of circ-CD44 suppressed proliferation, migration, and invasion while it increased OXA sensitivity and apoptosis in OXA-resistant colorectal cancer cells, which was overturned by suppression of miR-330-5p; besides, silencing of circ-CD44 also slowed the tumor growth in vivo. Additionally, overexpression of miR-330-5p inhibited chemotherapy resistance, proliferation, migration, and invasion while it induced apoptosis by targeting ABCC1.

CONCLUSION

Mechanistically, circ-CD44 functioned as a miRNA sponge for miR-330-5p to upregulate the expression of ABCC1 and regulate chemotherapy resistance in CRC cells.

Isothiocyanates (ITCs) 1-(Isothiocyanatomethyl)-4-phenylbenzene and 1-Isothiocyanato-3,5-bis(trifluoromethyl)benzene—Aldehyde Dehydrogenase (ALDH) Inhibitors, Decreases Cisplatin Tolerance and Migratory Ability of NSCLC

One of the main treatment modalities for non-small-cell lung cancer (NSCLC) is cisplatin-based chemotherapy. However, the acquisition of cisplatin resistance remains a major problem. Existing chemotherapy regimens are often ineffective against cancer cells expressing aldehyde dehydrogenase (ALDH). As such, there is an urgent need for therapies targeting ALDH-positive cancer cells. The present study compares the anticancer properties of 36 structurally diverse isothiocyanates (ITCs) against NSCLC cells with the ALDH inhibitor disulfiram (DSF). Their potential affinity to ALDH isoforms and ABC proteins was assessed using AutoDockTools, allowing for selection of three compounds presenting the strongest affinity to all tested proteins. The selected ITCs had no impact on NSCLC cell viability (at tested concentrations), but significantly decreased the cisplatin tolerance of cisplatin-resistant variant of A549 (A549CisR) and advanced (stage 4) NSCLC cell line H1581. Furthermore, long-term supplementation with ITC 1-(isothiocyanatomethyl)-4-phenylbenzene reverses the EMT phenotype and migratory potential of A549CisR to the level presented by parental A549 cells, increasing E-Cadherin expression, followed by decreased expression of ABCC1 and ALDH3A1. Our data indicates that the ALDH inhibitors DSF and ITCs are potential adjuvants of cisplatin chemotherapy.

The Impact of the Microbiome on Resistance to Cancer Treatment with Chemotherapeutic Agents and Immunotherapy

Understanding the mechanisms of resistance to therapy in human cancer cells has become a multifaceted limiting factor to achieving optimal cures in cancer patients. Besides genetic and epigenetic alterations, enhanced DNA damage repair activity, deregulation of cell death, overexpression of transmembrane transporters, and complex interactions within the tumor microenvironment, other mechanisms of cancer treatment resistance have been recently proposed. In this review, we will summarize the preclinical and clinical studies highlighting the critical role of the microbiome in the efficacy of cancer treatment, concerning mainly chemotherapy and immunotherapy with immune checkpoint inhibitors. In addition to involvement in drug metabolism and immune surveillance, the production of microbiota-derived metabolites might represent the link between gut/intratumoral bacteria and response to anticancer therapies. Importantly, an emerging trend of using microbiota modulation by probiotics and fecal microbiota transplantation (FMT) to overcome cancer treatment resistance will be also discussed.

Glycyrrhizin as a Nitric Oxide Regulator in Cancer Chemotherapy

Simple Summary

Glycyrrhizin (GL) has anti-cancer, anti-inflammatory, anti-viral, and anti-oxidant activity. In particular, GL reduces multidrug resistance (MDR) in cancer cells, which is a major obstacle to chemotherapy. Nitric oxide (NO) also plays an important role in MDR, and GL affects NO concentration in the tumor microenvironment. However, the effects of GL and NO interaction on MDR have not been reviewed. Here, we review the role of GL as an NO regulator in cancer cells and its subsequent anti-MDR effect and posit that GL is a promising MDR inhibitor for cancer chemotherapy.

Abstract

Chemotherapy is used widely for cancer treatment; however, the evolution of multidrug resistance (MDR) in many patients limits the therapeutic benefits of chemotherapy. It is important to overcome MDR for enhanced chemotherapy. ATP-dependent efflux of drugs out of cells is the main mechanism of MDR. Recent studies have suggested that nitric oxide (NO) can be used to overcome MDR by inhibiting the ATPase function of ATP-dependent pumps. Several attempts have been made to deliver NO to the tumor microenvironment (TME), however there are limitations in delivery. Glycyrrhizin (GL), an active compound of licorice, has been reported to both reduce the MDR effect by inhibiting ATP-dependent pumps and function as a regulator of NO production in the TME. In this review, we describe the potential role of GL as an NO regulator and MDR inhibitor that efficiently reduces the MDR effect in cancer chemotherapy.

The Long-Term DEHP Exposure Confers Multidrug Resistance of Triple-Negative Breast Cancer Cells through ABC Transporters and Intracellular ROS

The characteristics of phthalates had been thought to be similar to endocrine disruptors, which increases cancer risk. The role of phthalates in acquired drug resistance remains unclear. In this study, we investigated the effect of di-(2-ethylhexyl) phthalate (DEHP) on acquired drug resistance in breast cancer. MCF7 and MDA-MB-231 breast cancer cells were exposed to long-term physiological concentration of DEHP for more than three months. Long-exposure DEHP permanently attenuated the anti-proliferative effect of doxorubicin with estrogen receptor-independent activity even after withdrawal of DEHP. Long term DEHP exposure significantly reduced ROS (O2-) level in MDA-MB-231 cells while increased in MCF7 cells. ATP-binding cassette (ABC) transporters possess a widely recognized mechanism of drug resistance and are considered a target for drug therapy. Upregulation of ABC family proteins, ABCB-1 and ABCC-1 observed in DEHP-exposed clones compared to doxorubicin-resistant (DoxR) and parental MDA-MB-231 cells. A viability assay showed enhanced multidrug resistance in DEHP-exposed clones against Dox, topotecan, and irinotecan. Inhibition of ABC transporters with tariquidar, enhanced drug cytotoxicity through increased drug accumulation reversing acquired multidrug resistance in MDA-MB-231 breast cancer cells. Tariquidar enhanced Dox cytotoxicity by increasing intracellular ROS production leading to caspase-3 mediated apoptosis. Activation of PI3K/Akt signaling enhanced proliferation and growth of DEHP-exposed MDA-MB-231 cells. Overall, long-term DEHP exposure resulted in acquired multidrug resistance by upregulating ABCB-1 and ABCC1; apart from proliferation PI3K/Akt may be responsible for acquired drug resistance through ABC transporter upregulation. Targeting ABCB1 and ABCC1 with tariquidar may be a promising strategy for reversing the acquired multidrug resistance of triple-negative breast cancer cells.

Extracellular Vesicles in Chemoresistance

Chemotherapy represents the current mainstay therapeutic approach for most types of cancer. Despite the development of targeted chemotherapeutic strategies, the efficacy of anti-cancer drugs is severely limited by the development of drug resistance. Multidrug resistance (MDR) consists of the simultaneous resistance to various unrelated cytotoxic drugs and is one of the main causes of anticancer treatment failure. One of the principal mechanisms by which cancer cells become MDR involves the overexpression of ATP Binding Cassette (ABC) transporters, such as P-glycoprotein (P-gp), mediating the active efflux of cytotoxic molecules from the cytoplasm. Extracellular vesicles (EVs) are submicron lipid-enclosed vesicles that are released by all cells and which play a fundamental role in intercellular communication in physiological and pathological contexts. EVs have fundamental function at each step of cancer development and progression. They mediate the transmission of MDR through the transfer of vesicle cargo including functional ABC transporters as well as nucleic acids, proteins and lipids. Furthermore, EVs mediate MDR by sequestering anticancer drugs and stimulate cancer cell migration and invasion. EVs also mediate the communication with the tumour microenvironment and the immune system, resulting in increased angiogenesis, metastasis and immune evasion. All these actions contribute directly and indirectly to the development of chemoresistance and treatment failure. In this chapter, we describe the many roles EVs play in the acquisition and spread of chemoresistance in cancer. We also discuss possible uses of EVs as pharmacological targets to overcome EV-mediated drug resistance and the potential that the analysis of tumour-derived EVs offers as chemoresistance biomarkers.

The Structure and Mechanism of Drug Transporters

Drug transporters are integral membrane proteins that play a critical role in drug disposition by affecting absorption, distribution, and excretion. They translocate drugs, as well as endogenous molecules and toxins, across membranes using ATP hydrolysis, or ion/concentration gradients. In general, drug transporters are expressed ubiquitously, but they function in drug disposition by being concentrated in tissues such as the intestine, the kidneys, the liver, and the brain. Based on their primary sequence and their mechanism, transporters can be divided into the ATP-binding cassette (ABC), solute-linked carrier (SLC), and the solute carrier organic anion (SLCO) superfamilies. Many X-ray crystallography and cryo-electron microscopy (cryo-EM) structures have been solved in the ABC and SLC transporter superfamilies or of their bacterial homologs. The structures have provided valuable insight into the structural basis of transport. This chapter will provide particular focus on the promiscuous drug transporters because of their effect on drug disposition and the challenges associated with them.

The role of long non-coding RNAs in mediating chemoresistance by modulating autophagy in cancer

Cancer is a complex process in which protein-coding and non-coding genes play essential roles. Long noncoding RNAs (lncRNAs), as a subclass of noncoding genes, are implicated in various cancer processes including growth, proliferation, metastasis, and angiogenesis. Due to presence in body fluids such as blood and urine, lncRNAs have become novel biomarkers in cancer detection, diagnosis, progression, and therapy response. Remarkably, increasing evidence has verified that lncRNAs play essential roles in chemoresistance by targeting different signalling pathways. Autophagy, a highly conserved process in response to environmental stresses such as starvation and hypoxia, plays a paradoxical role in inducing resistance or sensitivity to chemotherapy agents. In this regard, we reviewed chemoresistance, the role of lncRNAs in cancer, and the role of lncRNAs in chemoresistance by modulating autophagy.

In vitro function and in situ localization of Multidrug Resistance-associated Protein (MRP)1 (ABCC1) suggest a protective role against methyl mercury-induced oxidative stress in the human placenta

Methyl mercury (MeHg) is an organic highly toxic compound that is transported efficiently via the human placenta. Our previous data suggest that MeHg is taken up into placental cells by amino acid transporters while mercury export from placental cells mainly involves ATP binding cassette (ABC) transporters. We hypothesized that the ABC transporter multidrug resistance-associated protein (MRP)1 (ABCC1) plays an essential role in mercury export from the human placenta. Transwell transport studies with MRP1-overexpressing Madin-Darby Canine Kidney (MDCK)II cells confirmed the function of MRP1 in polarized mercury efflux. Consistent with this, siRNA-mediated MRP1 gene knockdown in the human placental cell line HTR-8/SVneo resulted in intracellular mercury accumulation, which was associated with reduced cell viability, accompanied by increased cytotoxicity, apoptosis, and oxidative stress as determined via the glutathione (GSH) status. In addition, the many sources claiming different localization of MRP1 in the placenta required a re-evaluation of its localization in placental tissue sections by immunofluorescence microscopy using an MRP1-specific antibody that was validated in-house. Taken together, our results show that (1) MRP1 preferentially mediates apical-to-basolateral mercury transport in epithelial cells, (2) MRP1 regulates the GSH status of placental cells, (3) MRP1 function has a decisive influence on the viability of placental cells exposed to low MeHg concentrations, and (4) the in situ localization of MRP1 corresponds to mercury transport from maternal circulation to the placenta and fetus. We conclude that MRP1 protects placental cells from MeHg-induced oxidative stress by exporting the toxic metal and by maintaining the placental cells' GSH status in equilibrium.

Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations

The treatment of the posterior-segment ocular diseases, such as age-related eye diseases (AMD) or diabetic retinopathy (DR), present a challenge for ophthalmologists due to the complex anatomy and physiology of the eye. This specialized organ is composed of various static and dynamic barriers that restrict drug delivery into the target site of action. Despite numerous efforts, effective intraocular drug delivery remains unresolved and, therefore, it is highly desirable to improve the current treatments of diseases affecting the posterior cavity. This review article gives an overview of pharmacokinetic and biopharmaceutics aspects for the most commonly-used ocular administration routes (intravitreal, topical, systemic, and periocular), including information of the absorption, distribution, and elimination, as well as the benefits and limitations of each one. This article also encompasses different conventional and novel drug delivery systems designed and developed to improve drug pharmacokinetics intended for the posterior ocular segment treatment.

Identification of Novel Rare ABCC1 Transporter Mutations in Tumor Biopsies of Cancer Patients

The efficiency of chemotherapy drugs can be affected by ATP-binding cassette (ABC) transporter expression or by their mutation status. Multidrug resistance is linked with ABC transporter overexpression. In the present study, we performed rare mutation analyses for 12 ABC transporters related to drug resistance (ABCA2, -A3, -B1, -B2, -B5, -C1, -C2, -C3, -C4, -C5, -C6, -G2) in a dataset of 18 cancer patients. We focused on rare mutations resembling tumor heterogeneity of ABC transporters in small tumor subpopulations. Novel rare mutations were found in ABCC1, but not in the other ABC transporters investigated. Diverse ABCC1 mutations were found, including nonsense mutations causing premature stop codons, and compared with the wild-type protein in terms of their protein structure. Nonsense mutations lead to truncated protein structures. Molecular docking and heat map analyses of ABCC1/MRP1 pointed out that Lys498* appeared in a separate cluster branch due to the large deletion, leading to a massive disruption in the protein conformation. The resulting proteins, which are nonfunctional due to nonsense mutations in tumors, offer a promising chemotherapy strategy since tumors with nonsense mutations may be more sensitive to anticancer drugs than wild-type ABCC1-expressing tumors. This could provide a novel tumor-specific toxicity strategy and a way to overcome drug resistance.

Novel association between heterozygous genotype of single nucleotide polymorphism C218T in drug transporter ABCC1 gene and increased risk of colon cancer

Objectives:

To determine the role of G128C and C218T variants in ABCC1 gene with the risk of developing colon cancer in Jeddah, Kingdom of Saudi Arabia.

Methods:

This case-control study was conducted on 51 colon cancer patients and 65 controls from King Abdulaziz University Hospital and King Abdullah Medical City in the period from January 2015 to April 2017, and was approved by the Unit of Biomedical Ethics (no: 261-15). Experiments were performed in the experimental biochemistry unit at King Fahd Medical Research Center. The genotype distributions and allele frequencies were determined by polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) and DNA sequencing. A Chi-square test was used to determine allele and genotype distributions, odds ratio (OR), risk ratio (RR) and 95% confidence intervals (CI). P-values of <0.05 were considered statistically significant.

Results:

The results showed a novel association between heterozygous (CT) genotype for variant C218T and increased risk of colon cancer [OR=3.4, 95% CI (1.56-7.48), and RR=1.92, 95% CI (1.26-2.93), p=0.002]. These ratios were correlated with high-grade stages (III and IV). In contrast, for variant G128C, there was no significant association with the risk of developing colon cancer.

Conclusion:

The novel findings of the study revealed that the CT genotype of variant C218T in ABCC1 gene may increase the risk of developing colon cancer.

Drug resistance and combating drug resistance in cancer

Cancer is the second leading cause of death in the US. Current major treatments for cancer management include surgery, cytotoxic chemotherapy, targeted therapy, radiation therapy, endocrine therapy and immunotherapy. Despite the endeavors and achievements made in treating cancers during the past decades, resistance to classical chemotherapeutic agents and/or novel targeted drugs continues to be a major problem in cancer therapies. Drug resistance, either existing before treatment (intrinsic) or generated after therapy (acquired), is responsible for most relapses of cancer, one of the major causes of death of the disease. Heterogeneity among patients and tumors, and the versatility of cancer to circumvent therapies make drug resistance more challenging to deal with. Better understanding the mechanisms of drug resistance is required to provide guidance to future cancer treatment and achieve better outcomes. In this review, intrinsic and acquired resistance will be discussed. In addition, new discoveries in mechanisms of drug resistance will be reviewed. Particularly, we will highlight roles of ATP in drug resistance by discussing recent findings of exceptionally high levels of intratumoral extracellular ATP as well as intracellular ATP internalized from extracellular environment. The complexity of drug resistance development suggests that combinational and personalized therapies, which should take ATP into consideration, might provide better strategies and improved efficacy for fighting drug resistance in cancer.

New ABCC2 rs3740066 and rs2273697 Polymorphisms Identified in a Healthy Colombian Cohort

Multidrug resistance-associated proteins (MRP) 1 and 2 belong to the ABC (ATP-Binding Cassette) transporters. These transport proteins are involved in the removal of various drugs and xenobiotics, as well as in multiple physiological, pathological, and pharmacological processes. There is a strong correlation between different polymorphisms and their clinical implication in resistance to antiepileptic drugs, anticancer, and anti-infective agents. In our study, we evaluated exon regions of MRP1 (ABCC1)/MRP2 (ABCC2) in a Colombian cohort of healthy subjects to determine single nucleotide polymorphisms (SNPs) and to determine the allelic and genomic frequency. Results showed there are SNPs in our population that have been previously reported for both MRP1/ABCC1 (rs200647436, rs200624910, rs150214567) and MRP2/ABCC2 (rs2273697, rs3740066, rs142573385, rs17216212). Additionally, 13 new SNPs were identified. Evidence also shows a significant clinical correlation for polymorphisms rs3740066 and rs2273697 in the transport of multiple drugs, which suggests a genetic variability in regards to that reported in other populations.

ABCB1 and ABCC1 single-nucleotide polymorphisms in patients treated with clozapine

Clozapine (CZ) has superior efficacy to other antipsychotic agents in the treatment of schizophrenia and has been extensively used in clinical practice. ATP-binding cassette (ABC) transporter proteins are responsible for the distribution of various molecules as well as drugs across extracellular and intracellular membranes, including the blood-brain barrier. Genetic variations in these proteins can account for differences in treatment response. We investigated the influence of ABCB1 rs1045642 and ABCC1 rs212090 single-nucleotide polymorphisms (SNPs) on CZ serum level, clinical outcome, and changes in body mass index (BMI) in the first year of CZ treatment. These polymorphisms influenced baseline BMI in males (p=0.009 and 0.054, B1 and C1, respectively), changes in BMI in males after 3 (p=0.026, ABCB1) and 12 months (p=0.022, ABCC1) of CZ treatment, and level of diastolic pressure (p=0.002 and 0.051, respectively). The combination of ABCB1 + ABCC1 homozygote SNPs was associated with increased CZ and norclozapine serum levels (p=0.054 and 0.010, respectively). ABC transporter SNPs could be potential biomarkers for CZ-induced weight gain and cardiovascular complications. Further pharmacogenetic research is warranted to help clinicians with their treatment decision, including concomitant use of drugs and prevention of side effects.

Detection approaches for multidrug resistance genes of leukemia

Leukemia is a clonal malignant hematopoietic stem cell disease. It is the sixth most lethal cancer and accounts for 4% of all cancers. The main form of treatment for leukemia is chemotherapy. While some cancer types with a higher incidence than leukemia, such as lung and gastric cancer, have shown a sharp decline in mortality rates in recent years, leukemia has not followed this trend. Drug resistance is often regarded as the main clinical obstacle to effective chemotherapy in patients diagnosed with leukemia. Many resistance mechanisms have now been identified, and multidrug resistance (MDR) is considered the most important and prevalent mechanism involved in the failure of chemotherapy in leukemia. In order to reverse MDR and improve leukemia prognosis, effective detection methods are needed to identify drug resistance genes at initial diagnosis. This article provides a comprehensive overview of published approaches for the detection of MDR in leukemia. Identification of relevant MDR genes and methods for early detection of these genes will be needed in order to treat leukemia more effectively.

miR-7 modulates chemoresistance of small cell lung cancer by repressing MRP1/ABCC1

MicroRNAs (miRNAs) represent a class of small non-coding RNAs and have been shown to play important roles in various biological processes including cell growth, differentiation and apoptosis by regulating the target genes. miR-7 has been described not only as a tumour suppressor gene but also as an oncogene in human cancers. The aim of this study was to investigate the functional roles of miR-7 in chemoresistance of SCLC and its underlying mechanism. By using a bioinformatic assay, we found that MRP1/ABCC1 was a potential target gene of miR-7. Expression of miR-7 and MRP1/ABCC1 was examined in 44 SCLC samples by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry methods. Low-level expression of miR-7 was associated significantly with drug responsiveness and overall survival rate of patients with SCLC, but not with gender, age and stage. There was an inverse relationship between miR-7 and MRP1/ABCC1 expression. Downregulation of MRP1/ABCC1 level was revealed after transfection with a miR-7 mimic in H69 AR cells. Transfection of a miR-7 inhibitor into H69 cells restored MRP1/ABCC1 expression. A dual-luciferase reporter assay confirmed that miR-7 targeted predicted sites in the 3'-untranslated region (3'-UTR) of the MRP1/ABCC1 gene. Our data suggested that miR-7 mediated SCLC chemoresistance by repressing MRP1/ABCC1 and may be a prognostic predictor and potential therapeutic target in human SCLC.

Meta-analysis on pharmacogenetics of platinum-based chemotherapy in non small cell lung cancer (NSCLC) patients

AIM

To determine the pharmacogenetics of platinum-based chemotherapy in Non Small Cell Lung Cancer (NSCLC) patients.

METHODS

Publications were selected from PubMed, Cochrane Library and ISI Web of Knowledge. A meta-analysis was conducted to determine the association between genetic polymorphisms and platinum-based chemotherapy by checking odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Data were extracted from 24 publications, which included 11 polymorphisms in 8 genes for meta-analysis. MDR1 C3435T (OR = 1.97, 95% CI: 1.11-3.50, P = 0.02), G2677A/T (OR = 2.61, 95% CI: 1.44-4.74, P = 0.002) and GSTP1 A313G (OR = 0.32, 95% CI: 0.17-0.58, P = 0.0002) were significantly correlated with platinum-based chemotherapy in Asian NSCLC patients.

CONCLUSION

Attention should be paid to MDR1 C3435T, G2677A/T and GSTP1 A313G for personalized chemotherapy treatment for NSCLC patients in Asian population in the future.