Gene Summary

Gene:ABCA1; ATP binding cassette subfamily A member 1
Summary:The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intracellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the ABC1 subfamily. Members of the ABC1 subfamily comprise the only major ABC subfamily found exclusively in multicellular eukaryotes. With cholesterol as its substrate, this protein functions as a cholesteral efflux pump in the cellular lipid removal pathway. Mutations in this gene have been associated with Tangier's disease and familial high-density lipoprotein deficiency. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:phospholipid-transporting ATPase ABCA1; ATP-binding cassette sub-family A member 1
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
Show (50)
Pathways:What pathways are this gene/protein implicaed in?
Show (2)

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: ABCA1 (cancer-related)

Boulate G, Amazit L, Naman A, et al.
Potentiation of mitotane action by rosuvastatin: New insights for adrenocortical carcinoma management.
Int J Oncol. 2019; 54(6):2149-2156 [PubMed] Related Publications
Mitotane (also termed o,p'‑DDD) is the most effective therapy for advanced adrenocortical carcinoma (ACC). Mitotane‑induced dyslipidemia is treated with statins. Mitotane and statins are known to exert anti‑proliferative effects in vitro; however, the effects of statins have never been directly evaluated in patients with ACC and ACC cells, at least to the best of our knowledge. Thus, in this study, we aimed to examine the effects of the rosuvastatin on ACC cells. It has been shown that the combined use of mitotane and statins significantly increases the tumor control rate in patients with ACC; however, it would be of interest to elucidate the molecular mechanisms involved in this potentiation. In this study, we examined the effects of mitotane, rosuvastatin and their combination in NCI‑H295R human ACC cells using proliferation assays, gene expression analyses and free intracellular cholesterol measurements. The results revealed that mitotane dose‑dependently reduced cell viability, induced apoptosis and increased intracellular free cholesterol levels, considered as one of the key features of mitotane action, while rosuvastatin alone reduced cell viability and increased apoptosis at high concentrations. We also demonstrated that rosuvastatin potentiated the effects of mitotane by reducing cell viability, inducing apoptosis, increasing intracellular free cholesterol levels, and by decreasing the expression of 3‑hydroxy‑3‑methylglutaryl‑CoA reductase (HMGCR) and ATP binding cassette subfamily a member 1 (ABCA1), genes involved in cholesterol metabolism, and inhibiting steroidogenesis. Collectively, potentiating the effects of mitotane with the use of rosuvastatin may provide novel therapeutic strategies for ACC, given that the combination of these drugs, pending clinical validation, may lead to the better management of ACC.

Torres-Adorno AM, Vitrac H, Qi Y, et al.
Eicosapentaenoic acid in combination with EPHA2 inhibition shows efficacy in preclinical models of triple-negative breast cancer by disrupting cellular cholesterol efflux.
Oncogene. 2019; 38(12):2135-2150 [PubMed] Free Access to Full Article Related Publications
Triple-negative breast cancer (TNBC), the most aggressive breast cancer subtype, currently lacks effective targeted therapy options. Eicosapentaenoic acid (EPA), an omega-3 fatty acid and constituent of fish oil, is a common supplement with anti-inflammatory properties. Although it is not a mainstream treatment, several preclinical studies have demonstrated that EPA exerts anti-tumor activity in breast cancer. However, against solid tumors, EPA as a monotherapy is clinically ineffective; thus, we sought to develop a novel targeted drug combination to bolster its therapeutic action against TNBC. Using a high-throughput functional siRNA screen, we identified Ephrin type-A receptor 2 (EPHA2), an oncogenic cell-surface receptor tyrosine kinase, as a therapeutic target that sensitizes TNBC cells to EPA. EPHA2 expression was uniquely elevated in TNBC cell lines and patient tumors. In independent functional expression studies in TNBC models, EPHA2 gene-silencing combined with EPA significantly reduced cell growth and enhanced apoptosis compared with monotherapies, both in vitro and in vivo. EPHA2-specific inhibitors similarly enhanced the therapeutic action of EPA. Finally, we identified that therapy-mediated apoptosis was attributed to a lethal increase in cancer cell membrane polarity due to ABCA1 inhibition and subsequent dysregulation of cholesterol homeostasis. This study provides new molecular and preclinical evidence to support a clinical evaluation of EPA combined with EPHA2 inhibition in patients with TNBC.

Stokes E, Shuang T, Zhang Y, et al.
Efflux inhibition by H
Life Sci. 2018; 213:116-125 [PubMed] Related Publications
AIMS: Hydrogen sulfide (H
MATERIALS AND METHODS: Human primary hepatocellular carcinoma cell line (HepG2) and doxorubicin (Dox)-resistant cells were used in this study. Cell survival was analyzed by MTT, Annexin V-FITC/propidium iodide staining and clonogenic assay. Western blotting was used for analysis of protein expression, and immunoprecipitation was used to determine interactions of LXR/RXR.
KEY FINDINGS: The expression of H
SIGNIFICANCE: Our study provides a novel solution for reversing drug resistance in cancer cells by targeting H

Pattanayak SP, Bose P, Sunita P, et al.
Bergapten inhibits liver carcinogenesis by modulating LXR/PI3K/Akt and IDOL/LDLR pathways.
Biomed Pharmacother. 2018; 108:297-308 [PubMed] Related Publications
Oxysterol receptors LXRs (α and β) are recently reported to be one of the novel and potential therapeutic targets in reducing cell proliferation and tumor growth in different system model. Activation of LXRs is correlated with modification of PI3K/Akt pathway. LXRs are also found to play a critical role in maintaining lipid homeostatais by regulating ABCA1, IDOL, SREBP1, LDLR and also certain lipogenic genes such as FASN and SCD1. In the present study a potential furanocoumarin, Bergapten (BeG) has been evaluated for its anticancer property on Hepatocellular Carcinoma (HCC) on LXR axis. The molecular docking analysis was carried out for BeG on LXR (α & β) using Maestro tool and compared with reference ligands. This was followed by in vitro (HepG2 cell lines) and in vivo (on NDEA induced HCC in Wistar albino rats) anticancer evaluation of BeG. The docking results revealed polar and hydrophobic interactions of BeG with LXR (α,β). The in vitro studies revealed the potential of BeG in lowering the accumulation of lipid droplets in HepG2 cells which was correlated with increase in LXR (α,β) protein expressions. Furthermore, the in vivo studies demonstrated the potential of BeG in ameliorating the cancer induced alterations in body weight, liver weight and significant restoration of the changes in mRNA and protein expressions of LXR(α,β), ABCA1, IDOL, SREBP1 and LDLR. BeG also modulated the expressions of PI3K, Akt and certain lipogenic genes like FASN and SCD1 and reduced the lipid droplets level in liver cancer cells. These results provide evidence and validates the critical role of BeG in maintaining the lipid homeostasis and justifies its anticancer potential against NDEA-induced HCC.

Aguirre-Portolés C, Feliu J, Reglero G, Ramírez de Molina A
ABCA1 overexpression worsens colorectal cancer prognosis by facilitating tumour growth and caveolin-1-dependent invasiveness, and these effects can be ameliorated using the BET inhibitor apabetalone.
Mol Oncol. 2018; 12(10):1735-1752 [PubMed] Free Access to Full Article Related Publications
At the time of diagnosis, 20% of patients with colorectal cancer present metastasis. Among individuals with primary lesions, 50% of them will develop distant tumours with time. Therefore, early diagnosis and prediction of aggressiveness is crucial for therapy design and disease prognosis. Tumoral cells must undergo significant changes in energy metabolism to meet increased structural and energetic demands for cell proliferation, and metabolic alterations are considered to be a hallmark of cancer. Here, we present the ATP-binding cassette transporter (ABCA1), a regulator of cholesterol transport, as a new marker for invasion and colorectal cancer survival. ABCA1 is significantly overexpressed in patients at advanced stages of colorectal cancer, and its overexpression confers proliferative advantages together with caveolin-1 dependent-increased migratory and invasive capacities. Thus, intracellular cholesterol imbalances mediated by ABCA1 overexpression may contribute to primary tumour growth and dissemination to distant locations. Furthermore, we demonstrate here that increased levels of apolipoprotein A1 (APOA1), a protein involved in cholesterol efflux and high-density lipoprotein constitution, in the extracellular compartment modulates expression of ABCA1 by regulating COX-2, and compensate for ABCA1-dependent excessive export of cholesterol. APOA1 emerges as a new therapeutic option to inhibit the promotion of colorectal cancer to metastasis by modulating intracellular cholesterol metabolism. Furthermore, we propose apabetalone, an orally available small molecule that is currently being evaluated in clinical trials for the treatment of atherosclerosis, as a new putative therapeutic option to prevent colorectal cancer progression by increasing APOA1 expression and regulating reverse transport of cholesterol.

Wittkowski KM, Dadurian C, Seybold MP, et al.
Complex polymorphisms in endocytosis genes suggest alpha-cyclodextrin as a treatment for breast cancer.
PLoS One. 2018; 13(7):e0199012 [PubMed] Free Access to Full Article Related Publications
Most breast cancer deaths are caused by metastasis and treatment options beyond radiation and cytotoxic drugs, which have severe side effects, and hormonal treatments, which are or become ineffective for many patients, are urgently needed. This study reanalyzed existing data from three genome-wide association studies (GWAS) using a novel computational biostatistics approach (muGWAS), which had been validated in studies of 600-2000 subjects in epilepsy and autism. MuGWAS jointly analyzes several neighboring single nucleotide polymorphisms while incorporating knowledge about genetics of heritable diseases into the statistical method and about GWAS into the rules for determining adaptive genome-wide significance. Results from three independent GWAS of 1000-2000 subjects each, which were made available under the National Institute of Health's "Up For A Challenge" (U4C) project, not only confirmed cell-cycle control and receptor/AKT signaling, but, for the first time in breast cancer GWAS, also consistently identified many genes involved in endo-/exocytosis (EEC), most of which had already been observed in functional and expression studies of breast cancer. In particular, the findings include genes that translocate (ATP8A1, ATP8B1, ANO4, ABCA1) and metabolize (AGPAT3, AGPAT4, DGKQ, LPPR1) phospholipids entering the phosphatidylinositol cycle, which controls EEC. These novel findings suggest scavenging phospholipids as a novel intervention to control local spread of cancer, packaging of exosomes (which prepare distant microenvironment for organ-specific metastases), and endocytosis of β1 integrins (which are required for spread of metastatic phenotype and mesenchymal migration of tumor cells). Beta-cyclodextrins (βCD) have already been shown to be effective in in vitro and animal studies of breast cancer, but exhibits cholesterol-related ototoxicity. The smaller alpha-cyclodextrins (αCD) also scavenges phospholipids, but cannot fit cholesterol. An in-vitro study presented here confirms hydroxypropyl (HP)-αCD to be twice as effective as HPβCD against migration of human cells of both receptor negative and estrogen-receptor positive breast cancer. If the previous successful animal studies with βCDs are replicated with the safer and more effective αCDs, clinical trials of adjuvant treatment with αCDs are warranted. Ultimately, all breast cancer are expected to benefit from treatment with HPαCD, but women with triple-negative breast cancer (TNBC) will benefit most, because they have fewer treatment options and their cancer advances more aggressively.

Phelan JD, Young RM, Webster DE, et al.
A multiprotein supercomplex controlling oncogenic signalling in lymphoma.
Nature. 2018; 560(7718):387-391 [PubMed] Free Access to Full Article Related Publications
B cell receptor (BCR) signalling has emerged as a therapeutic target in B cell lymphomas, but inhibiting this pathway in diffuse large B cell lymphoma (DLBCL) has benefited only a subset of patients

Lai SC, Phelps CA, Short AM, et al.
Thyroid transcription factor 1 enhances cellular statin sensitivity via perturbing cholesterol metabolism.
Oncogene. 2018; 37(24):3290-3300 [PubMed] Free Access to Full Article Related Publications
We have discovered an unexpected connection between a critical lung development and cancer gene termed thyroid transcription factor 1 (TTF-1 also known as NKX2-1) and cholesterol metabolism. Our published work implicates that TTF-1 positively regulates miR-33a which is known to repress ATP-binding cassette transporter 1 (ABCA1) and thus its cholesterol efflux activity. We set out to demonstrate that a higher TTF-1 expression would presumably inhibit cholesterol efflux and consequently raise intracellular cholesterol level. Surprisingly, raising TTF-1 expression actually lowers intracellular cholesterol level, which, we believe, is attributed to a direct transactivation of ABCA1 by TTF-1. Subsequently, we show that lung cancer cells primed with a TTF-1-driven decrease of cholesterol were more vulnerable to simvastatin, a frequently prescribed cholesterol biosynthesis inhibitor. In view of the fact that pathologists routinely interrogate human lung cancers for TTF-1 immunopositivity to guide diagnosis and the prevalent use of statins, TTF-1 should be further investigated as a putative biomarker of lung cancer vulnerability to statins.

Scott DW, King RL, Staiger AM, et al.
High-grade B-cell lymphoma with
Blood. 2018; 131(18):2060-2064 [PubMed] Free Access to Full Article Related Publications
High-grade B-cell lymphoma with

Phelps CA, Lai SC, Mu D
Roles of Thyroid Transcription Factor 1 in Lung Cancer Biology.
Vitam Horm. 2018; 106:517-544 [PubMed] Related Publications
Thyroid transcription factor 1 (TTF-1 or NKX2-1) is a transcription factor of fundamental importance in driving lung maturation and morphogenesis. In the last decade, scientists began to appreciate the functional roles of TTF-1 in lung tumorigenesis. This movement was triggered by the discoveries of genetic alterations of TTF-1 in the form of gene amplification in lung cancer. Many downstream target genes of TTF-1 relevant to the lung cancer biology of TTF-1 have been documented. One of the most surprising findings was that TTF-1 may exhibit either pro- or antitumorigenic activities, an outcome with the complexity exceeding the original anticipation purely based on the fact that TTF-1 undergoes gene amplification in lung cancer. In the coming decade, we believe, we will witness additional surprises as the research exploring the cancer roles of TTF-1 progresses.

Akhter MZ, Sharawat SK, Kumar V, et al.
Aggressive serous epithelial ovarian cancer is potentially propagated by EpCAM
Oncogene. 2018; 37(16):2089-2103 [PubMed] Related Publications
Epithelial ovarian carcinoma (EOC) patients often acquire resistance against common chemotherapeutic drugs like paclitaxel and cisplatin. The mechanism responsible for the same is ambiguous. We have identified a putative drug-resistant tumour cell phenotype (EpCAM

Furfari A, Wan BA, Ding K, et al.
Genetic biomarkers associated with changes in quality of life and pain following palliative radiotherapy in patients with bone metastases.
Ann Palliat Med. 2017; 6(Suppl 2):S248-S256 [PubMed] Related Publications
BACKGROUND: Patients with bone metastases undergoing palliative radiation therapy (RT) may experience changes in both the functional and symptomatic aspects of quality of life (QOL). The European Organization of Cancer Research and Treatment (EORTC) QOL Questionnaire Core-15 Palliative (QLQ-C15-PAL) is a validated questionnaire employed to assess QOL specifically in palliative patients. Our study aimed to identify single-nucleotide variant (SNV) genetic biomarkers associated with changes in QOL and pain.
METHODS: Fifty-two patients who received a single 8-Gy RT for painful bone metastases completed the EORTC QOL-C15-PAL questionnaire prior to randomization and at 42-day post RT. Saliva samples obtained at day of RT were sequenced, and SNVs from genes involved in inflammation, radiation response, immune response, DNA damage, or QOL were assessed for association with changes in global QOL or the pain scale items using the Cochran-Armitage trend test. The penalized LASSO method with minimum Bayesian information criterion was used to select a multi-SNV model out of significant SNVs (P<0.005) and to produce prognostic scores for patients that categorized them into risk groups of low, middle, and high.
RESULTS: The multivariable model predicting global QOL included 14 SNVs, of which HS1BP3 rs35579164 G:C and ABCA1 rs2230805 C>T had the largest positive and negative effect sizes, respectively (HS1BP3: 8.21, ABCA1: -3.44). The model for the response of QOL pain item included 8 SNVs, of which PLAUR rs4760 A>G and ELAC2rs11545302 had the largest positive and negative effect sizes, respectively (PLAUR: 5.23; ELAC: -3.84). The patients' risk groups were highly predictive of QOL response (P<0.0001) and pain item response (P<0.0001). In logistic regression analysis accounting for baseline factors of gender and primary cancer site, the global QOL risk group predicts pain response after RT [OR: 2.1, 95% confidence interval (CI): 1.2-3.9, P=0.015], but the QOL pain item risk group did not (OR: 0.93; 95% CI: 0.5-1.6, P=0.79). The multi-SNVs model included SNVs from genes involved in metabolism, membrane transport, cell cycle control, ciliary structure, and gene expression regulation.
CONCLUSIONS: SNVs were significantly associated with changes in global QOL of global domain and pain item in patients with bone metastases. Identification of genetic biomarkers predictive of QOL items may allow patients and health care providers anticipate and better address the needs of the palliative cancer patient population.

Bobin-Dubigeon C, Chauvin A, Brillaud-Meflah V, et al.
Liver X Receptor (LXR)-regulated Genes of Cholesterol Trafficking and Breast Cancer Severity.
Anticancer Res. 2017; 37(10):5495-5498 [PubMed] Related Publications
BACKGROUND: Liver X receptor [LXR; nuclear receptor subfamily 1, group H, member 2 (NR1H2, alias LXRB)] can inhibit proliferation and induce apoptosis of cancer cells. Its relationship with disease severity is not known.
MATERIALS AND METHODS: Expression of LXRB, ATP binding cassette subfamily A member 1 (ABCA1), ATP binding cassette subfamily G member 1 (ABCG1), apolipoprotein E (APOE) and paraoxonase 2 (PON2) were determined in 69 breast tumors and were related to clinical stages of the disease and tumor characteristics, as well as time to recurrence.
RESULTS: ABCG1 expression differed with the tumor Scarff Bloom and Richardson (SBR) status (p=0.02), with a lower expression in SBRIII than in SBRII and SBRI. ABCG1 expression was significantly higher in estrogen receptor-positive tumors (N=63) (p=0.02). APOE expression was significantly lower in progesterone receptor-positive tumors (N=55) (p=0.03). No relationship with time to recurrence was observed.
CONCLUSION: Expression of some LXR-dependent genes is related to breast tumor characteristics, but not time to recurrence. This may be due to a lack of study power or too short a follow-up time.

Stopsack KH, Gerke TA, Andrén O, et al.
Cholesterol uptake and regulation in high-grade and lethal prostate cancers.
Carcinogenesis. 2017; 38(8):806-811 [PubMed] Free Access to Full Article Related Publications
Lethal prostate cancers have higher expression of squalene monooxygenase (SQLE), the second rate-limiting enzyme of cholesterol synthesis. Preclinical studies suggested that aberrant cholesterol regulators, receptors and transporters contribute to cholesterol accumulation uniformly. We assessed their association with features of aggressive cancers. In the prospective prostate cancer cohorts within the Health Professional Follow-up Study, the Physicians' Health Study and the Swedish Watchful Waiting Study, tumor mRNA expression profiling was performed. Lethal disease was defined as mortality or metastases from prostate cancer (n = 266) in contrast to non-lethal disease without metastases after >8 years of follow-up (n = 476). Associations with Gleason grade were additionally assessed using The Cancer Genome Atlas primary prostate cancer dataset (n = 333). Higher Gleason grade was associated with lower LDLR expression, lower SOAT1 and higher SQLE expression. Besides high SQLE expression, cancers that became lethal despite primary treatment were characterized by low LDLR expression (odds ratio for highest versus lowest quintile, 0.37; 95% CI 0.18-0.76) and by low SOAT1 expression (odds ratio, 0.41; 95% CI 0.21-0.83). The association of LDLR expression and lethality was not present in tumors with high IDOL expression. ABCA1, PCSK9 or SCARB1 expressions were not associated with Gleason grade or lethal cancer. In summary, prostate cancers that progress to lethal disease rely on de novo cholesterol synthesis (via SQLE), rather than transcellular uptake (via LDLR) or cholesterol esterification (via SOAT1). These results may help design pharmacotherapy for high-risk patients.

Moazzeni H, Najafi A, Khani M
Identification of direct target genes of miR-7, miR-9, miR-96, and miR-182 in the human breast cancer cell lines MCF-7 and MDA-MB-231.
Mol Cell Probes. 2017; 34:45-52 [PubMed] Related Publications
Some microRNAs have carcinogenic or tumor suppressive effects in breast cancer, which is the most common cancer in women worldwide. MiR-7 and miR-9 are tumor suppressor microRNAs, which induce apoptosis and inhibit proliferation in breast cancer cells. Moreover, miR-96 and miR-182 are onco-microRNAs that increase proliferation, migration, and tumorigenesis in breast cancer cells. This study aimed to identify the direct target genes of these four microRNAs in the human breast cancer cell lines MCF-7 and MDA-MB-231. Initially, bioinformatics tools were used to identify the target genes that have binding sites for miR-7, MiR-9, MiR-96, and miR-182 and are also associated with breast cancer. Subsequently, the findings of the bioinformatics analysis relating to the effects of these four microRNAs on the 3'-UTR activity of the potential target genes were confirmed using the dual luciferase assay in MCF-7 and MDA-MB-231 cells co-transfected with the vectors containing 3'-UTR segments of the target genes downstream of a luciferase coding gene and each of the microRNAs. Finally, the effects of microRNAs on the endogenous expression of potential target genes were assessed by the overexpression of each of the four microRNAs in MCF-7 and MDA-MB-231 cells. Respectively, three, three, three, and seven genes were found to have binding sites for miR-7, miR-9, miR-96, and miR-182 and were associated with breast cancer. The results of empirical studies including dual luciferase assays and real-time PCR confirmed that miR-7 regulates the expression of BRCA1 and LASP1; MiR-9 regulates the expression of AR; miR-96 regulates the expression of ABCA1; and miR-182 regulates the expression of NBN, TOX3, and LASP1. Taken together, our results suggest that the tumor suppressive effects of miR-7 may be mediated partly by regulating the expression of BRCA1 as a tumor suppressor gene in breast cancer. In addition, this microRNA and miR-182 may have effects on the nodal-positivity and tumor size of breast carcinoma through the regulation of LASP1. The tumor suppressive functions of miR-9 may be mediated partly by suppressing the expression of AR-an oncogene in breast cancer. Moreover, miR-96 may play an oncogenic role in breast cancer by suppressing the apoptosis through the regulation of ABCA1.

Wu X, Cheng J, Wang X
Dietary Antioxidants: Potential Anticancer Agents.
Nutr Cancer. 2017 May-Jun; 69(4):521-533 [PubMed] Related Publications
There are several extrinsic and intrinsic factors involving reactive oxygen species that play critical roles in tumor development and progression by inducing DNA mutations, genomic instability, and aberrant pro-tumorigenic signaling. There are various essential micronutrients including minerals and vitamins in the diet, which play pivotal roles in maintaining and reinforcing antioxidant performance, affecting the complex network of genes (nutrigenomic approach) and encoding proteins for carcinogenesis. A lot of these antioxidant agents are available as dietary supplements and are predominant worldwide. However, the best antioxidant micronutrient (or a combination of micronutrients) for reducing cancer risks is unknown. The purpose of this review is to survey the literature on modern biological theories of cancer and the roles of dietary antioxidants in cancer. The roles and functions of antioxidant micronutrients, such as vitamin C (ascorbate), vitamin E (alpha-tocopherol), selenium, and vitamin A, provided through diet for the prevention of cancer are discussed in the present work.

Onishi H, Suyama K, Yamasaki A, et al.
CD24 Modulates Chemosensitivity of MCF-7 Breast Cancer Cells.
Anticancer Res. 2017; 37(2):561-565 [PubMed] Related Publications
The role of cluster of differentiation (CD) 24 in breast cancer remains unclear; previously, we showed that CD24 suppresses malignant phenotypes by inactivating Hedgehog signaling through signal transducer and activator of transcription (STAT) 1 inhibition. In this study, we examined how CD24 affects chemosensitivity in breast cancer cells. The CD44

Gadaleta F, Bessonov K, Van Steen K
Integration of gene expression and methylation to unravel biological networks in glioblastoma patients.
Genet Epidemiol. 2017; 41(2):136-144 [PubMed] Related Publications
The vast amount of heterogeneous omics data, encompassing a broad range of biomolecular information, requires novel methods of analysis, including those that integrate the available levels of information. In this work, we describe Regression2Net, a computational approach that is able to integrate gene expression and genomic or methylation data in two steps. First, penalized regressions are used to build Expression-Expression (EEnet) and Expression-Genomic or Expression-Methylation (EMnet) networks. Second, network theory is used to highlight important communities of genes. When applying our approach, Regression2Net to gene expression and methylation profiles for individuals with glioblastoma multiforme, we identified, respectively, 284 and 447 potentially interesting genes in relation to glioblastoma pathology. These genes showed at least one connection in the integrated networks ANDnet and XORnet derived from aforementioned EEnet and EMnet networks. Although the edges in ANDnet occur in both EEnet and EMnet, the edges in XORnet occur in EMnet but not in EEnet. In-depth biological analysis of connected genes in ANDnet and XORnet revealed genes that are related to energy metabolism, cell cycle control (AATF), immune system response, and several cancer types. Importantly, we observed significant overrepresentation of cancer-related pathways including glioma, especially in the XORnet network, suggesting a nonignorable role of methylation in glioblastoma multiforma. In the ANDnet, we furthermore identified potential glioma suppressor genes ACCN3 and ACCN4 linked to the NBPF1 neuroblastoma breakpoint family, as well as numerous ABC transporter genes (ABCA1, ABCB1) suggesting drug resistance of glioblastoma tumors.

Vargas T, Moreno-Rubio J, Herranz J, et al.
3'UTR Polymorphism in ACSL1 Gene Correlates with Expression Levels and Poor Clinical Outcome in Colon Cancer Patients.
PLoS One. 2016; 11(12):e0168423 [PubMed] Free Access to Full Article Related Publications
Strong evidence suggests that lipid metabolism (LM) has an essential role in tumor growth to support special energetic and structural requirements of tumor cells. Recently, overexpression of LM-related genes, apolipoproteins related to metabolic syndrome, and ACSL/SCD network involved in fatty acid activation have been proposed as prognostic markers of colon cancer (CC). Furthermore, activation of this latter lipid network has been recently demonstrated to confer invasive and stem cell properties to tumor cells promoting tumor aggressiveness and patient relapse. With the aim of elucidating whether any genetic variation within these genes could influence basal expression levels and consequent susceptibility to relapse, we genotype, in 284 CC patients, 57 polymorphisms located in the 7 genes of these lipid networks previously associated with worse clinical outcome of CC patients (ABCA1, ACSL1, AGPAT1, APOA2, APOC1, APOC2 and SCD), some of them related to CC aggressiveness. After adjusting with clinical confounding factors and multiple comparisons, an association between genotype and disease-free survival (DFS) was shown for rs8086 in 3'-UTR of ACSL1 gene (HR 3.08; 95% CI 1.69-5.63; adjusted p = 0.046). Furthermore, the risk T/T genotype had significantly higher ACSL1 gene expression levels than patients carrying C/T or C/C genotype (means = 5.34; 3.73; 2.37 respectively; p-value (ANOVA) = 0.019), suggesting a functional role of this variant. Thus, we have identified a "risk genotype" of ACSL1 gene that confers constitutive high levels of the enzyme, which is involved in the activation of fatty acids through conversion to acyl-CoA and has been recently related to increased invasiveness of tumor cells. These results suggest that rs8086 of ACSL1 could be a promising prognostic marker in CC patients, reinforcing the relevance of LM in the progression of CC.

Hou H, Kang Y, Li Y, et al.
miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via ABCA1.
Neoplasma. 2017; 64(1):81-91 [PubMed] Related Publications
Cancer stem cells (CSCs) are responsible for the unrestrained cell growth and chemo-resistance of malignant tumors. Reports about miR-33a in different type of cancer are limited, and it remains elusive whether there is a link between miR-33a and chemo-resistance of CSCs. Here we report that Lgr5+ hepatocellular carcinoma (HCC) cells from primary tissues and cell lines behave similarly to CSCs and are chemo-resistant to doxorubicin. Significantly, reduced miR-33a expression is associated with the chemo-resistance of Lgr5+ HCC-CSCs, accompanied by an overexpression of ABCA1 which is identified as target of miR-33a by mainly using miRNA luciferase assay and western-blotting. We demonstrate that down-regulation of miR-33a expression directly contributes to chemo-resistance of Lgr5+ HCC-CSCs, and restoring miR-33a expression sensitizes them to doxorubicin via apoptosis by mainly using TUNEL assay, soft agar colony formation assay and xenograft assay. Additionally, reduced miR-33a expression in HCC tissues is associated with chemo-response and poor patient survival, which suggests the therapeutic potential of miR-33a. In conclusion, our work indicates that ectopic miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via direct targeting ABCA1, which sheds new light on understanding the mechanism of chemo-resistance in HCC-CSCs and contributes to development of potential therapeutics against HCC.

Derkaoui T, Bakkach J, Mansouri M, et al.
Triple negative breast cancer in North of Morocco: clinicopathologic and prognostic features.
BMC Womens Health. 2016; 16(1):68 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Triple Negative Breast Cancer (TNBC) is defined by a lack of estrogen and progesterone receptor gene expression and by the absence of overexpression on HER2. It is associated to a poor prognosis. We propose to analyze the clinicopathologic and prognostic characteristics of this breast cancer subtype in a Mediterranean population originated or resident in the North of Morocco.
METHODS: We conducted a retrospective study of 279 patients diagnosed with breast cancer between January 2010 and January 2015. Clinicopathologic and prognostic features have been analyzed. Disease-Free Survival (DFS) and Overall Survival (OS) have been estimated.
RESULTS: Of all cases, forty-nine (17.6 %) were identified as having triple negative breast cancer with a median age of 46 years. The average tumor size was 3.6 cm. The majority of patients have had invasive ductal carcinoma (91.8 %) and 40.4 % of them were grade III SBR. Nodal metastasis was detected in 38.9 % of the patients and vascular invasion was found in 36.6 % of them. About half of the patients had an early disease (53.1 %) and 46.9 % were diagnosed at an advanced stage. Patients with operable tumors (61.2 %) underwent primary surgery and adjuvant chemotherapy. Patients with no operable tumors (26.5 %) received neoadjuvant chemotherapy followed by surgery, and patients with metastatic disease (12.2 %) were treated by palliative chemotherapy. DFS and OS at 5 years were respectively 83.7 and 71.4 %. Among 49, twelve had recurrences, found either when diagnosing them or after a follow-up. Local relapse was 6.1 %. Lung and liver metastases accounted consecutively for 8.2 and 10.2 %. Bone metastases were found in 4.1 % and brain metastases in 2.1 % of the cases.
CONCLUSION: Our results are in accordance with literature data, particularly what concerning young age and poor prognosis among TNBC phenotype. Therefore, the identification of BRCA mutations in our population seems to be essential in order to better adapt management options for this aggressive form of breast cancer.

Ceroi A, Masson D, Roggy A, et al.
LXR agonist treatment of blastic plasmacytoid dendritic cell neoplasm restores cholesterol efflux and triggers apoptosis.
Blood. 2016; 128(23):2694-2707 [PubMed] Free Access to Full Article Related Publications
Blastic plasmacytoid dendritic cell (PDC) neoplasm (BPDCN) is an aggressive hematological malignancy with a poor prognosis that derives from PDCs. No consensus for optimal treatment modalities is available today and the full characterization of this leukemia is still emerging. We identified here a BPDCN-specific transcriptomic profile when compared with those of acute myeloid leukemia and T-acute lymphoblastic leukemia, as well as the transcriptomic signature of primary PDCs. This BPDCN gene signature identified a dysregulation of genes involved in cholesterol homeostasis, some of them being liver X receptor (LXR) target genes. LXR agonist treatment of primary BPDCN cells and BPDCN cell lines restored LXR target gene expression and increased cholesterol efflux via the upregulation of adenosine triphosphate-binding cassette (ABC) transporters, ABCA1 and ABCG1. LXR agonist treatment was responsible for limiting BPDCN cell proliferation and inducing intrinsic apoptotic cell death. LXR activation in BPDCN cells was shown to interfere with 3 signaling pathways associated with leukemic cell survival, namely: NF-κB activation, as well as Akt and STAT5 phosphorylation in response to the BPDCN growth/survival factor interleukin-3. These effects were increased by the stimulation of cholesterol efflux through a lipid acceptor, the apolipoprotein A1. In vivo experiments using a mouse model of BPDCN cell xenograft revealed a decrease of leukemic cell infiltration and BPDCN-induced cytopenia associated with increased survival after LXR agonist treatment. This demonstrates that cholesterol homeostasis is modified in BPDCN and can be normalized by treatment with LXR agonists which can be proposed as a new therapeutic approach.

Bollschweiler E, Hölscher AH, Herbold T, et al.
Molecular Markers for the Prediction of Minor Response to Neoadjuvant Chemoradiation in Esophageal Cancer: Results of the Prospective Cologne Esophageal Response Prediction (CERP) Study.
Ann Surg. 2016; 264(5):839-846 [PubMed] Related Publications
OBJECTIVE: The aim of this study was to evaluate the predictive value of a single or combination of biomarker(s) for histopathologic non-response to neoadjuvant chemoradiation in esophageal cancer.
SUMMARY OF BACKGROUND DATA: Patients without response to neoadjuvant chemoradiation for esophageal cancer have no prognostic benefits, but experience time delays and risk side effects.
METHODS: Inclusion criteria for this prospective diagnostic study were patients with cT3,Nx,M0, esophageal squamous cell or adenocarcinoma and planned neoadjuvant chemoradiation (5- fluorouracil, cisplatin, 40Gy) followed by 2-field transthoracic esophagectomy. From pretherapeutic endoscopic tumor biopsies, ERCC1 rs11615 single-nucleotide polymorphism (ERCC1-SNP) and a combination of gene expression marker mRNA (ERCC1, DPYD, ERBB2) were analyzed. ERCC1-SNP was subdifferentiated into homozygous C-allele (CC) and T-allele (TT), and heterozygous C/T carriers. The primary endpoint was the prediction of histopathological minor response (≥10% vital tumor cells in the primary tumor) relative to marker levels.
RESULTS: From 2009 until 2013, 320 patients were screened, and 85 patients (SCC n = 29, AC n = 56) were included in the study. Forty-one patients (48%) had major response with 3-year survival rate (3-YSR) of 57% compared with 44 patients with minor response and 3-YSR of 25% (P = 0.001). Patients with ERCC1-SNP CC (n = 8) and TT (n = 37) had similar rates of minor response of 70% and 75%, and a positive predictive value (PPV) of 71% [95% confidence interval (CI 56%-84%)]. PPV increased to 89% (95% CI 73%-96%) when ERCC1-SNP was combined with mRNA markers.
CONCLUSION: ERCC1-SNP in combination with mRNA ERCC1, DPYD, and ERBB2 from pretherapeutic endoscopic biopsies can predict minor response to chemoradiation, as a basis for individualized therapy of advanced esophageal cancer.

Shukla A, Moussa A, Singh TR
DREMECELS: A Curated Database for Base Excision and Mismatch Repair Mechanisms Associated Human Malignancies.
PLoS One. 2016; 11(6):e0157031 [PubMed] Free Access to Full Article Related Publications
DNA repair mechanisms act as a warrior combating various damaging processes that ensue critical malignancies. DREMECELS was designed considering the malignancies with frequent alterations in DNA repair pathways, that is, colorectal and endometrial cancers, associated with Lynch syndrome (also known as HNPCC). Since lynch syndrome carries high risk (~40-60%) for both cancers, therefore we decided to cover all three diseases in this portal. Although a large population is presently affected by these malignancies, many resources are available for various cancer types but no database archives information on the genes specifically for only these cancers and disorders. The database contains 156 genes and two repair mechanisms, base excision repair (BER) and mismatch repair (MMR). Other parameters include some of the regulatory processes that have roles in these disease progressions due to incompetent repair mechanisms, specifically BER and MMR. However, our unique database mainly provides qualitative and quantitative information on these cancer types along with methylation, drug sensitivity, miRNAs, copy number variation (CNV) and somatic mutations data. This database would serve the scientific community by providing integrated information on these disease types, thus sustaining diagnostic and therapeutic processes. This repository would serve as an excellent accompaniment for researchers and biomedical professionals and facilitate in understanding such critical diseases. DREMECELS is publicly available at

Motazacker MM, Pirhonen J, van Capelleveen JC, et al.
A loss-of-function variant in OSBPL1A predisposes to low plasma HDL cholesterol levels and impaired cholesterol efflux capacity.
Atherosclerosis. 2016; 249:140-7 [PubMed] Related Publications
BACKGROUND AND AIMS: Among subjects with high-density-lipoprotein cholesterol (HDL-C) below the 1st percentile in the general population, we identified a heterozygous variant OSBPL1A p.C39X encoding a short truncated protein fragment that co-segregated with low plasma HDL-C.
METHODS: We investigated the composition and function of HDL from the carriers and non-carriers and studied the properties of the mutant protein in cultured hepatocytes.
RESULTS: Plasma HDL-C and apolipoprotein (apo) A-I were lower in carriers versus non-carriers, whereas the other analyzed plasma components or HDL parameters did not differ. Sera of the carriers displayed a reduced capacity to act as cholesterol efflux acceptors (p < 0.01), whereas the cholesterol acceptor capacity of their isolated HDL was normal. Fibroblasts from a p.C39X carrier showed reduced cholesterol efflux to lipid-free apoA-I but not to mature HDL particles, suggesting a specific defect in ABCA1-mediated efflux pathway. In hepatic cells, GFP-OSBPL1A partially co-localized in endosomes containing fluorescent apoA-I, suggesting that OSBPL1A may regulate the intracellular handling of apoA-I. The GFP-OSBPL1A-39X mutant protein remained in the cytosol and failed to interact with Rab7, which normally recruits OSBPL1A to late endosomes/lysosomes, suggesting that this mutation represents a loss-of-function.
CONCLUSIONS: The present work represents the first characterization of a human OSBPL1A mutation. Our observations provide evidence that a familial loss-of-function mutation in OSBPL1A affects the first step of the reverse cholesterol transport process and associates with a low HDL-C phenotype. This suggests that rare mutations in OSBPL genes may contribute to dyslipidemias.

Bi DP, Yin CH, Zhang XY, et al.
MiR-183 functions as an oncogene by targeting ABCA1 in colon cancer.
Oncol Rep. 2016; 35(5):2873-9 [PubMed] Related Publications
Colon cancer remains the second most common cause of cancer-related death, indicating that a proportion of cancer cells are not eradicated by current therapies. Investigation of the molecular mechanisms involved in the development and progression of the disease will aid in the further understanding of the pathogenesis and progression and offer new targets for effective therapies. In the present study, we initially confirmed that ABCA1 was aberrantly expressed in colon cancer tissues and colon cancer cells. Its overexpression inhibited the proliferation of colon cancer HCT116 cells while silencing of ABCA1 promoted the proliferation and inhibited the apoptosis of colon cancer LDL1 cells. Upregulation of specific miRNAs can contribute to the downregulation of tumor-suppressive genes. Thus, we aimed to ascertain whether ABCA1 is downregulated by overexpression of a specific miRNA in colon cancer. We screened microRNAs that may target ABCA1 by miRanda which is a commonly used prediction algorithm. We found that miR-183 targets the 3'UTR of ABCA1 mRNA. Subsequent experiments confirmed that miR-183 degraded ABCA1 mRNA in the colon cancer cells. Finally, we demonstrated that miR-183 promoted the proliferation and inhibited the apoptosis of colon cancer cells. Thus, we conclude that miR-183 promotes proliferation and inhibits apoptosis by degrading ABCA1 in colon cancer.

Ye P, Xing H, Lou F, et al.
Histone deacetylase 2 regulates doxorubicin (Dox) sensitivity of colorectal cancer cells by targeting ABCB1 transcription.
Cancer Chemother Pharmacol. 2016; 77(3):613-21 [PubMed] Related Publications
PURPOSE: Histone deacetylases (HDACs) have been shown to regulate cell cycle, differentiation, and apoptosis of colorectal cancer (CRC) cells, while their roles in drug sensitivity remain unclear. The objectives of the present study were to investigate the effects of HDAC2 on drug resistance of CRC cells.
METHODS: We measured the expression of class I HDACs (HDAC1, 2, 3, 8) in CRC and human normal colonic epithelial cells. Additionally, we inhibited HDAC2 via siRNA or overexpressed it via pcDNA/HDAC2 transfection to evaluate its roles in doxorubicin (Dox) sensitivity.
RESULTS: Our present study showed HDAC2 was significantly increased in CRC cell lines as compared to human normal colonic epithelial cells. Silencing of HDAC2 can obviously enhance the sensitivity of HCT-116 and SW480 cells to dDox. Further, knockdown of HDAC2 can significantly (p < 0.05) downregulate the expression of ABCB1, while not ABCG2, ABCC1, ABCA1, or ABCC2. Inhibition of HDAC2 decreased ABCB1 promoter activities and the phosphorylation of c-fos and c-Jun, which can directly interact with the ABCB1 promoter and then promote its transcription. Overexpression of HDAC2 by pcDNA/HDAC2 transfection significantly increased the sensitivity of CRC cells to Dox and upregulated the levels of P-gp, p-c-fos, and p-c-Jun.
CONCLUSIONS: Our data revealed that HDAC2 can regulate Dox sensitivity of CRC cells by targeting ABCB1 transcription. It suggested that HDAC2 might be an important target for CRC therapy. Further, the combination of HDAC2-specific inhibitor and anticancer drugs including Dox might be an efficiency approach to elevate the treatment outcome of CRC.

Zhao W, Prijic S, Urban BC, et al.
Candidate Antimetastasis Drugs Suppress the Metastatic Capacity of Breast Cancer Cells by Reducing Membrane Fluidity.
Cancer Res. 2016; 76(7):2037-49 [PubMed] Related Publications
Despite the high mortality from metastatic cancer, therapeutic targets to prevent metastasis are limited. Efforts to identify genetic aberrations that predispose tumors to metastasis have been mostly unsuccessful. To understand the nature of candidate targets for metastatic disease, we performed an in silico screen to identify drugs that can inhibit a gene expression signature associated with epithelial-mesenchymal transition (EMT). Compounds discovered through this method, including those previously identified, appeared to restrict metastatic capacity through a common mechanism, the ability to modulate the fluidity of cell membranes. Treatment of breast cancer cell lines with the putative antimetastasis agents reduced membrane fluidity, resulting in decreased cell motility, stem cell-like properties, and EMT in vitro, and the drugs also inhibited spontaneous metastasis in vivo When fluidity was unchanged, the antimetastasis compounds could no longer restrict metastasis, indicating a causal association between fluidity and metastasis. We further demonstrate that fluidity can be regulated by cellular cholesterol flux, as the cholesterol efflux channel ABCA1 potentiated metastatic behaviors in vitro and in vivo The requirement for fluidity was further supported by the finding in breast cancer patients that ABCA1 was overexpressed in 41% of metastatic tumors, reducing time to metastasis by 9 years. Collectively, our findings reveal increased membrane fluidity as a necessary cellular feature of metastatic potential that can be controlled by many currently available drugs, offering a viable therapeutic opportunity to prevent cancer metastasis. Cancer Res; 76(7); 2037-49. ©2016 AACR.

Sharma M, Tuaine J, McLaren B, et al.
Chemotherapy Agents Alter Plasma Lipids in Breast Cancer Patients and Show Differential Effects on Lipid Metabolism Genes in Liver Cells.
PLoS One. 2016; 11(1):e0148049 [PubMed] Free Access to Full Article Related Publications
Cardiovascular complications have emerged as a major concern for cancer patients. Many chemotherapy agents are cardiotoxic and some appear to also alter lipid profiles, although the mechanism for this is unknown. We studied plasma lipid levels in 12 breast cancer patients throughout their chemotherapy. Patients received either four cycles of doxorubicin and cyclophosphamide followed by weekly paclitaxel or three cycles of epirubicin, cyclophosphamide and 5'-fluorouracil followed by three cycles of docetaxel. Patients demonstrated a significant reduction (0.32 mmol/L) in high density lipoprotein cholesterol (HDL-C) and apolipoprotein A1 (apoA1) levels (0.18 g/L) and an elevation in apolipoprotein B (apoB) levels (0.15 g/L) after treatment. Investigation of the individual chemotherapy agents for their effect on genes involved in lipoprotein metabolism in liver cells showed that doxorubicin decreased ATP binding cassette transporter A1 (ABCA1) via a downregulation of the peroxisomal proliferator activated receptor γ (PPARγ) and liver X receptor α (LXRα) transcription factors. In contrast, ABCA1 levels were not affected by cyclophosphamide or paclitaxel. Likewise, apoA1 levels were reduced by doxorubicin and remained unaffected by cyclophosphamide and paclitaxel. Doxorubicin and paclitaxel both increased apoB protein levels and paclitaxel also decreased low density lipoprotein receptor (LDLR) protein levels. These findings correlate with the observed reduction in HDL-C and apoA1 and increase in apoB levels seen in these patients. The unfavourable lipid profiles produced by some chemotherapy agents may be detrimental in the longer term to cancer patients, especially those already at risk of cardiovascular disease (CVD). This knowledge may be useful in tailoring effective follow-up care plans for cancer survivors.

Wu TC, Lin YC, Chen HL, et al.
The enhancing effect of genistein on apoptosis induced by trichostatin A in lung cancer cells with wild type p53 genes is associated with upregulation of histone acetyltransferase.
Toxicol Appl Pharmacol. 2016; 292:94-102 [PubMed] Related Publications
Genistein has been shown to enhance the antitumor activity of trichostatin A (TSA) in human lung carcinoma A549 cells. However, whether the combined treatment exerts the same effect in other lung cancer cells is unclear. In the present study we first compared the enhancing effect of genistein on the antitumor effect of TSA in ABC-1, NCI-H460 (H460) and A549 cells. Second, we investigated whether the effects of genistein are associated with increased histone/non-histone protein acetylation. We found that the enhancing effect of genistein on cell-growth-arrest in ABC-1 cells (p53 mutant) was less than in A549 and H460 cells. Genistein enhanced TSA induced apoptosis in A549 and H460 cells rather than in ABC-1 cells. After silencing p53 expression in A549 and H460 cells, the enhancing effect of genistein was diminished. In addition, genistein increased TSA-induced histone H3/H4 acetylation in A549 and H460 cells. Genistein also increased p53 acetylation in H460 cells. The inhibitor of acetyltransferase, anacardic acid, diminished the enhancing effect of genistein on all TSA-induced histone/p53 acetylation and apoptosis. Genistein in combination with TSA increased the expression of p300 protein, an acetyltransferase, in A549 and NCI-H460 cells. Furthermore, we demonstrated that genistein also enhanced the antitumor effect of genistein in A549-tumor-bearing mice. Taken together, these results suggest that the enhancing effects of genistein on TSA-induced apoptosis in lung cancer cells were p53-dependent and were associated with histone/non-histone protein acetylation.

Disclaimer: This site is for educational purposes only; it can not be used in diagnosis or treatment.

Cite this page: Cotterill SJ. ABCA1, Cancer Genetics Web: Accessed:

Creative Commons License
This page in Cancer Genetics Web by Simon Cotterill is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Note: content of abstracts copyright of respective publishers - seek permission where appropriate.

 [Home]    Page last revised: 31 August, 2019     Cancer Genetics Web, Established 1999