circRNA basic information
circBase ID: hsa_circ_0078310
Name: hsa_circ_ESR1
Synonym: circESR1
Host Gene: ESR1
Genomic location(hg19): chr6:152201789-152265643:+
Genomic location(hg38): chr6:151880654-151944508:+
Subcellular localization: nucleus and cytoplasm
 
 
 
 
 
 
 
Disease basic information
MONDO ID:
 0006512
MONDO name: estrogen-receptor positive breast cancer
Disease details: ER-positive breast cancer
Disease DO ID:
 0060075
Disease MeSH ID:
 -
Disease NCIt ID:
 -
Disease ICD11 ID:
 -
Disease OMIM ID:
 -
Species: Human
Species details: Homo sapiens
Tissue specimen:

tumor tissues; matched adjacent normal tissues; paraffin-embedded ER+ BC specimens; breast hyperplasia (benign)
Cell lines:

MCF-7; T-47D; CAMA-1; MCF-10A; HMEC-hTERT; 293T; HCC1937; MDA-MB-231; SUM159PT
In vivo animal model:

cell line-derived xenograft
circRNA-disease information
Expression pattern:
UP
Associated gene: HNRNPAB, CDK1 mRNA, CDK6 mRNA
Associated microRNA: -
Biological function: promotes cell viability; promotes cell cycle progression/transition; inhibits apoptosis; promotes antiestrogen resistance; enhances sensitivity to CDK4/6 inhibitors upon depletion
Molecular mechanism: circESR1 binds HNRNPAB and increases HNRNPAB stability by reducing ubiquitination; forms a positive feedback loop where HNRNPAB promotes circESR1 back-splicing by binding Alu elements of ESR1 pre-mRNA; circESR1 facilitates HNRNPAB recruitment/stabilization of CDK1 and CDK6 mRNAs to promote cell cycle progression
Biological pathway or process:

cell cycle (promotes); proliferation (promotes); apoptosis (inhibits); drug resistance (promotes)
Detected method:
Q
B
H
S
Validation methods:

Back-Splice Junction PCR / divergent primers PCR; RNase R Treatment; Sanger Sequencing; Actinomycin D / DRB Stability Assay; RT-qPCR; RNA-seq; Northern Blot; FISH / smFISH; ISH (In Situ Hybridization); Nuclear-Cytoplasmic Fractionation; Clinical Sample Validation; RNA Pull-Down; RIP (RNA Immunoprecipitation); CLIP; Luciferase Reporter Assay; Transfection; MTT; Colony Formation Assay; Annexin V/PI Flow Cytometry; Cell Cycle Assay; In Vivo Animal Model; H&E Staining; IHC (Immunohistochemistry); Survival Analysis; Bioinformatics Analysis
Clinical significance:

Higher circESR1 expression correlated with advanced stage and worse overall survival in ER+ BC patients.
Description:

circESR1 (hsa_circ_0078310), derived from ESR1, is up-regulated in ER+ breast cancer and further increased in tamoxifen-resistant cells. It binds the RBP HNRNPAB, stabilizing HNRNPAB via reduced ubiquitination and forming a positive feedback loop in which HNRNPAB promotes circESR1 biogenesis by binding Alu elements of ESR1 pre-mRNA. Through this circESR1-HNRNPAB complex, CDK1 and CDK6 mRNAs are stabilized, promoting cell-cycle progression, proliferation and endocrine resistance; high circESR1 levels associate with advanced stage and poor survival.
Confidence score:

0.8982
Other information
Title:

The Interaction of CircESR1 and HNRNPAB Regulates Cell Cycle Transition of Breast Cancer Cell.

Journal: International journal of biological sciences
Published: 2026
PubMed ID: 41608617
Study type:

combined biological and clinical study
Data availability: -
Code availability: -