The earwax-associated SNP c.538G>A (G180R) in ABCC11 is not associated with breast cancer risk in Europeans

Pleiotropic Roles of ABC Transporters in Breast Cancer

Chemotherapeutics are the mainstay treatment for metastatic breast cancers. However, the chemotherapeutic failure caused by multidrug resistance (MDR) remains a pivotal obstacle to effective chemotherapies of breast cancer. Although in vitro evidence suggests that the overexpression of ATP-Binding Cassette (ABC) transporters confers resistance to cytotoxic and molecularly targeted chemotherapies by reducing the intracellular accumulation of active moieties, the clinical trials that target ABCB1 to reverse drug resistance have been disappointing. Nevertheless, studies indicate that ABC transporters may contribute to breast cancer development and metastasis independent of their efflux function. A broader and more clarified understanding of the functions and roles of ABC transporters in breast cancer biology will potentially contribute to stratifying patients for precision regimens and promote the development of novel therapies. Herein, we summarise the current knowledge relating to the mechanisms, functions and regulations of ABC transporters, with a focus on the roles of ABC transporters in breast cancer chemoresistance, progression and metastasis.

A functional single nucleotide polymorphism in ABCC11, rs17822931, is associated with the risk of breast cancer in Japanese

The adenosine triphosphate-binding cassette (ABC) transporter superfamily consists of membrane proteins which translocate various substrates across membranes. Because ABCC11, a member ABC transporter, is highly expressed in breast cancer tissue, it may be involved in the efflux of conjugated estrogen metabolites. rs17822931, a functional single nucleotide polymorphism (SNP) in ABCC11, may play a role in the carcinogenesis of breast cancer via estrogen. Here, we aimed to evaluate the association between ABCC11 rs17822931 and breast cancer risk in a Japanese population. We conducted a case-control study in 697 patients with breast cancer and 1394 age- and menopausal status-matched controls within the framework of the Hospital-based Epidemiological Research Program at Aichi Cancer Center II (HERPACC II). The association was evaluated with odds ratios (ORs) and 95% confidence intervals (CIs) calculated using a conditional logistic model adjusted for potential confounders. In the per allele model, compared with the A allele, the G allele was inversely associated with breast cancer: OR, 0.77, 95% CI, 0.62-0.95 and P = 0.013. The stratified analyses showed that this polymorphism had a high impact on estrogen receptor (ER)-positive breast cancer risk and conditions assumed to correlate with high exposure to estrogen, namely no lactation and low soy intake. Our data showed that a significant association between rs17822931 and the risk of breast cancer, especially ER-positive breast cancer, in Japanese women. Compared to women with low estrogen efflux activity with the A allele, those with high efflux activity with the G allele may have a lower risk of breast cancer, particularly women with high estrogen exposure.

Advancements in Non-Invasive Biological Surface Sampling and Emerging Applications

Biological surfaces such as skin and ocular surface provide a plethora of information about the underlying biological activity of living organisms. However, they pose unique problems arising from their innate complexity, constant exposure of the surface to the surrounding elements, and the general requirement of any sampling method to be as minimally invasive as possible. Therefore, it is challenging but also rewarding to develop novel analytical tools that are suitable for in vivo and in situ sampling from biological surfaces. In this context, wearable extraction devices including passive samplers, extractive patches, and different microextraction technologies come forward as versatile, low-invasive, fast, and reliable sampling and sample preparation tools that are applicable for in vivo and in situ sampling. This review aims to address recent developments in non-invasive in vivo and in situ sampling methods from biological surfaces that introduce new ways and improve upon existing ones. Directions for the development of future technology and potential areas of applications such as clinical, bioanalytical, and doping analyses will also be discussed. These advancements include various types of passive samplers, hydrogels, and polydimethylsiloxane (PDMS) patches/microarrays, and other wearable extraction devices used mainly in skin sampling, among other novel techniques developed for ocular surface and oral tissue/fluid sampling.

Clioquinol: To harm or heal

Clioquinol, one of the first mass-produced drugs, was considered safe and efficacious for many years. It was used as an antifungal and an antiprotozoal drug until it was linked to an outbreak of subacute myelo-optic neuropathy (SMON), a debilitating disease almost exclusively confined to Japan. Today, new information regarding clioquinol targets and its mechanism of action, as well as genetic variation (SNPs) in efflux transporters in the Japanese population, provide a unique interpretation of the existing phenomena. Further understanding of clioquinol's role in the inhibition of cAMP efflux and promoting apoptosis might offer promise for the treatment of cancer and/or neurodegenerative diseases. Here, we highlight recent developments in the field and discuss possible connections, hypotheses and perspectives in clioquinol-related research.

ABC Family Transporters

The transport of specific molecules across lipid membranes is an essential function of all living organisms. The processes are usually mediated by specific transporters. One of the largest transporter families is the ATP-binding cassette (ABC) family. More than 40 ABC transporters have been identified in human, which are divided into 7 subfamilies (ABCA to ABCG) based on their gene structure, amino acid sequence, domain organization, and phylogenetic analysis. Of them, at least 11 ABC transporters including P-glycoprotein (P-GP/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs), and breast cancer resistance protein (BCRP/ABCG2) are involved in multidrug resistance (MDR) development. These ABC transporters are expressed in various tissues such as the liver, intestine, kidney, and brain, playing important roles in absorption, distribution, and excretion of drugs. Some ABC transporters are also involved in diverse cellular processes such as maintenance of osmotic homeostasis, antigen processing, cell division, immunity, cholesterol, and lipid trafficking. Several human diseases such as cystic fibrosis, sitosterolemia, Tangier disease, intrahepatic cholestasis, and retinal degeneration are associated with mutations in corresponding transporters. This chapter will describe function and expression of several ABC transporters (such as P-GP, BCRP, and MRPs), their substrates and inhibitors, as well as their clinical significance.

Diagnosis of Human Axillary Osmidrosis by Genotyping of the Human ABCC11 Gene: Clinical Practice and Basic Scientific Evidence

The importance of personalized medicine and healthcare is becoming increasingly recognized. Genetic polymorphisms associated with potential risks of various human genetic diseases as well as drug-induced adverse reactions have recently been well studied, and their underlying molecular mechanisms are being uncovered by functional genomics as well as genome-wide association studies. Knowledge of certain genetic polymorphisms is clinically important for our understanding of interindividual differences in drug response and/or disease risk. As such evidence accumulates, new clinical applications and practices are needed. In this context, the development of new technologies for simple, fast, accurate, and cost-effective genotyping is imperative. Here, we describe a simple isothermal genotyping method capable of detecting single nucleotide polymorphisms (SNPs) in the human ATP-binding cassette (ABC) transporter ABCC11 gene and its application to the clinical diagnosis of axillary osmidrosis. We have recently reported that axillary osmidrosis is linked with one SNP 538G>A in the ABCC11 gene. Our molecular biological and biochemical studies have revealed that this SNP greatly affects the protein expression level and the function of ABCC11. In this review, we highlight the clinical relevance and importance of this diagnostic strategy in axillary osmidrosis therapy.

Multidrug Resistance Proteins (MRPs) and Cancer Therapy

The ATP-binding cassette (ABC) transporters are members of a protein superfamily that are known to translocate various substrates across membranes, including metabolic products, lipids and sterols, and xenobiotic drugs. Multidrug resistance proteins (MRPs) belong to the subfamily C in the ABC transporter superfamily. MRPs have been implicated in mediating multidrug resistance by actively extruding chemotherapeutic substrates. Moreover, some MRPs are known to be essential in physiological excretory or regulatory pathways. The importance of MRPs in cancer therapy is also implied by their clinical insights. Modulating the function of MRPs to re-sensitize chemotherapeutic agents in cancer therapy shows great promise in cancer therapy; thus, multiple MRP inhibitors have been developed recently. This review article summarizes the structure, distribution, and physiological as well as pharmacological function of MRP1-MRP9 in cancer chemotherapy. Several novel modulators targeting MRPs in cancer therapy are also discussed.

ABCC11/MRP8 polymorphisms affect 5-fluorouracil-induced severe toxicity and hepatic expression

AIM

Because 5-fluorodeoxyuridine monophosphate (5-FdUMP), an anabolic active metabolite of 5-fluorouracil (5-FU), is a substrate of MRP8 (encoded by ABCC11), we investigated whether ABCC11 polymorphisms play a role in severe toxicity of 5-FU.

PATIENTS & METHODS

Genomic DNA from 672 cancer patients treated with 5-FU monotherapy and with documented toxicity according to WHO criteria was genotyped for 12 ABCC11 tag SNPs. Functional impact of polymorphisms was assessed in a Caucasian human liver cohort (n = 150) and by recombinant expression of MRP8 protein variants.

RESULTS

Univariate and multivariate analysis identified rs17822471 (G>A, T546M) as risk factor of severe leukopenia (p = 0.021, odds ratio [95%CI]: 3.31 [1.26-8.66]) but not of other toxicity types. MRP8 protein expression in human liver was 1.7-fold lower in carriers compared with wild-type (p = 0.02). Recombinant expression confirmed the effect of T546M on protein expression.

CONCLUSION

Since MRP8 is expressed in bone marrow blasts and leukocytes, lower expression may lead to intracellular accumulation of 5-FdUMP and increased risk of leukopenia.

High throughput volatile fatty acid skin metabolite profiling by thermal desorption secondary electrospray ionisation mass spectrometry

Global VOC skin metabolite profiling. Thermal desorption secondary electrospray ionisation time-of-flight mass spectrometry classifies skin odour phenotypes by targeted volatile fatty analysis. Examination of the mass spectra reveals the potential for global metabolic studies.

High expression of ATP-binding cassette transporter ABCC11 in breast tumors is associated with aggressive subtypes and low disease-free survival

ATP-binding cassette (ABC) transporters are membrane proteins that efflux various compounds from cells, including chemotherapeutic agents, and are known to affect multidrug resistance. Recent reports disagree on whether ABCC11 is a risk factor for breast tumorigenesis, but its expression in breast cancer is poorly investigated. We hypothesized that both frequency and expression levels of ABC transporters in breast tumors would vary by cancer subtype, and be associated with prognosis. Here, we constructed a tissue microarray breast tumor samples from 281 patients, and analyzed expressions of ABCB1, ABCC1, ABCC11, and ABCG2 immunohistochemically. Breast cancer subtypes were determined by immunohistochemistry of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). Protein expression was correlated to clinicopathological characteristics, clinical follow-up, and pathological complete response to neoadjuvant chemotherapy. The tissue microarray comprised 191 luminal A (68.0 %), 17 luminal B (6.0 %), 27 HER2 (9.6 %), and 46 triple-negative (16.4 %) samples. ABCC1 and ABCC11 expressions were associated with significantly shorter disease-free survival (P = 0.027 and P = 0.003, respectively). ABCC1, ABCC11, and ABCG2, but not ABCB1, were expressed significantly more, and more frequently, in aggressive subtypes. Patients with HER2+ and triple-negative tumor subtypes that expressed high levels of ABCC11 had significantly worse disease-free survival (P = 0.017 and P < 0.001, respectively). We have shown, for the first time, that ABCC1, ABCC11, and ABCG2 are highly expressed in aggressive breast cancer subtypes, and that tumor ABCC11 expression is associated with poor prognosis.

Pharmacogenetics of human ABC transporter ABCC11: new insights into apocrine gland growth and metabolite secretion

Cell secretion is an important physiological process that ensures smooth metabolic activities and tissue repair as well as growth and immunological functions in the body. Apocrine secretion occurs when the secretory process is accomplished with a partial loss of cell cytoplasm. The secretory materials are contained within secretory vesicles and are released during secretion as cytoplasmic fragments into the glandular lumen or interstitial space. The recent finding that the non-synonymous single nucleotide polymorphisms (SNP) 538G > A (rs17822931; Gly180Arg) in the ABCC11 gene determines the type of earwax in humans has shed light on the novel function of this ABC (ATP-binding cassette) transporter in apocrine glands. The wild-type (Gly180) of ABCC11 is associated with wet-type earwax, axillary osmidrosis, and colostrum secretion from the mammary gland as well as the potential risk of mastopathy. Furthermore, the SNP (538G > A) in the ABCC11 gene is suggested to be a clinical biomarker for the prediction of chemotherapeutic efficacy. The aim of this review article is to provide an overview on the discovery and characterization of genetic polymorphisms in the human ABCC11 gene and to explain the impact of ABCC11 538G > A on the apocrine phenotype as well as the anthropological aspect of this SNP in the ABCC11 gene and patients’ response to nucleoside-based chemotherapy.