Abstract
Abstract
Background:
Bladder cancer (BCa) is the most common genitourinary malignancy and causes substantial economic losses worldwide. Recent studies suggest overexpression of
circCD2AP
in BCa, but its mechanistic contributions to carcinogenesis and ferroptosis regulation remain unclear.
Methods:
From August 2021 to January 2024, 98 pairs of BCa and adjacent normal tissue samples were collected from the Third Xiangya Hospital, Central South University. Gene/protein expression, lipid reactive oxygen species (ROS) levels, and cell viability were analyzed. Interactions among
circCD2AP
/YTH domain-containing protein 1 (YTHDC1), circCD2AP, insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), and IGF2BP3/forkhead box C1 (FOXC1) were validated, along with
circCD2AP
-IGF2BP3 colocalization. FOXC1 binding sites in the Parkinson’s disease protein 7 (PARK7) promoter were mapped. N6-methyladenosine (m6A) modifications on
circCD2AP
were quantified via methylated RNA immunoprecipitation polymerase chain reaction.
Results:
circCD2AP was significantly upregulated in BCa and positively correlated with PARK7 expression (
R
2
= 0.1357,
P
= 0.0002). Patients with high
circCD2AP
expression showed poorer survival rates.
CircCD2AP
knockdown sensitized BCa cells to ferroptosis inducers (erastin and Ras-selective lethal small molecule 3). Methyltransferase-like 3 (
METTL3
) knockdown inhibited
circCD2AP
m6A modification and relative expression. YTHDC1 mediated m6A-dependent cytoplasmic export of circCD2AP (2.8-fold increase). Besides,
circCD2AP
stabilized
FOXC1
messenger RNA (mRNA), and FOXC1 bound the
PARK7
promoter to enhance its expression. Knockdown of
FOXC1
or
PARK7
blocked the antiferroptotic effect of
circCD2AP
overexpression in BCa cells. Knockdown of
METTL3
or
circCD2AP
reduced tumor burden in mice, decreasing both volume (approximately 48.3% or 56.4%) and weight (approximately 65.3% or 58.7%) through FOXC1/PARK7-mediated ferroptosis.
Conclusions:
METTL3-mediated m6A modification drives
circCD2AP
overexpression, which is subsequently exported to the cytoplasm with enhanced efficiency mediated by YTHDC1. Cytoplasmic
circCD2AP
stabilizes
FOXC1
mRNA, enabling FOXC1-dependent transcriptional activation of
PARK7
. This axis suppresses ferroptosis and promotes BCa progression, revealing a novel therapeutic target.