ABCG2

Background

Creative Biolabs provides an extensive selection of top-notch aptamers targeting ABCG2 to help researchers improve their experiments and research. Our standards for excellence are upheld, and we are dedicated to supporting your research in biology.

Introduction

The gene ABC subfamily G subtype 2 (ABCG2) encodes the breast cancer resistance protein (BCRP or ABCG2). It is found on chromosome 4q22 and comprises 16 exons and 15 introns, covering a distance of 66 kb. ABCG2 protein is an ATP-binding cassette (ABC) efflux transporter with a protein size of 72 kDa and 655 amino acids, which plays an important role in drug response. Excessive activity and increased production of the ABCG2 protein have been linked to resistance to chemotherapy, which includes tyrosine kinase inhibitors.

Fig.1 The transmembrane ABCG2 channel. Distributed under CC BY-SA 4.0, from Wiki, without modification.

The ABCG2 protein, functioning as an efflux transporter, plays a role in safeguarding tissues from xenobiotics and harmful metabolites. It is found on the apical cell membranes in various parts of the body such as the placenta, brain, prostate, gastrointestinal tract, testes, ovaries, hepatocytes, renal tubules, stem cells, adrenal glands, uterus, bile ducts, gallbladder, central nervous system, and venous and capillary endothelial cells, facilitating the absorption, distribution, and elimination of substrates. The highest expression of ABCG2 is in brain tissue, uterus, cervix, and small intestine. The efflux function of ABCG2 acts as a protective barrier in tissues that are the center of substrate absorption and elimination.

Function

ABCG2 also plays some important physiological functions in normal tissues, such as serving as the first line of defense to protect organisms from environmental aggressions. In the placenta, ABCG2 is considered to be part of the maternal-fetal barrier. There is also a theory that it helps transport steroid hormones produced in the placenta. ABCG2 expression is present on the luminal surface of the brain microvascular endothelium, indicating that it plays a role in the blood-brain barrier. It is an important barrier for drugs to enter the brain, protecting the brain from the invasion of xenobiotic toxicity. The therapeutic drugs are also impeded in reaching their targets in the brain. In the gastrointestinal tract, the expression of ABCG2 suggests that it plays an important role in limiting the absorption of drugs and toxins.

ABCG2 in Multidrug Resistance

ABCG2 is associated with multidrug resistance in cancer, and the latter is a major barrier to successful cancer treatment. One way cells can become resistant to chemotherapy is by expressing ABC transporters. These transporters can use the energy from ATP hydrolysis to transport a wide range of substrates across the cell membrane. ABCG2 is one of three human ABC transporters implicated in the phenomenon of multidrug resistance, the other two being P-gp (P-glycoprotein) and MRP1 (Multidrug Resistance Protein 1). Substrates of ABCG2 include mitoxantrone, methotrexate, topotecan, flavonoids, and irinotecan.

ABCG2 Aptamer Analysis

Creative Biolabs provides aptamers specifically targeting ABCG2, renowned for their accuracy in binding to the ABCG2 protein. These aptamers are instrumental in propelling research and innovation in aptamer-based therapeutic and diagnostic strategies. In addition, we offer functional assays for anti-ABCG2 aptamers to assist our clients further.

Fig.2 Anti-ABCG2 aptamer-based cancer stem cells-targeted therapeutic strategies.¹

Evaluating ABCG2 aptamer assays encompasses several stages, including the use of SELEX to select aptamers that bind to the ABCG2 protein. Subsequently, confirming the specific binding of anti-ABCG2 aptamers to ABCG2 is conducted through FACS analysis and fluorescence microscopy. To analyze functional activity, the inhibitory effect of anti-ABCG2 aptamers on cancer cell proliferation and growth can be tested over time using a colony formation assay. Additionally, cell proliferation is assessed by performing an MTT assay on cells treated with the aptamers.

Creative Biolabs is dedicated to maintaining exceptional quality and driving forward innovations in its aptamer offerings. By utilizing cutting-edge technologies and enforcing rigorous quality controls, we deliver dependable and effective anti-ABCG2 aptamers customized to fulfill client needs. These anti-ABCG2 aptamers can concurrently bind to both monomers of ABCG2 dimers, effectively obstructing the ABCG2-mediated drug-efflux channel, and leading to enhanced intracellular retention of substrate drugs. This research paves the way for developing affinity reagents aimed at targeting cancer stem cells and overcoming multidrug resistance, presenting promising opportunities in cancer diagnosis and therapy.

Reference

1. Liu, Biao, et al. "Recent advances in aptamer-based therapeutic strategies for targeting cancer stem cells." Materials Today Bio 19 (2023): 100605. Distributed under Open Access license CC BY 4.0, without modification.