Background: Ferroptosis, a distinct iron-dependent
form of regulated cell death, is induced by severe lipid peroxidation due to
reactive oxygen species (ROS) generation. Breast cancer patient survival is
correlated with the tumor-suppressing properties of Rho guanosine triphosphatase hydrolase enzyme (GTPase)-activating protein
6 (ARHGAP6). This study investigates the impact and mechanisms of ARHGAP6 on
ferroptosis in breast cancer. Methods: Using quantitative
RT-PCR, Western blotting, and immunofluorescence staining, ARHGAP6 expression was
detected in a gene expression dataset, cancer tissue samples, and cells. ARHGAP6
was overexpressed or silenced in breast cancer cell lines. Cell proliferation was
measured using 5-ethynyl-2-deoxyuridine (EdU) assay, and cell death rate was
determined using LDH cytotoxicity assay. As indicators of ferroptosis, Fe
ion content, lipid ROS, glutathione peroxidase 4 (GPX4), ChaC glutathione
specific gamma-glutamylcyclotransferase 1 (CHAC1), prostaglandin-endoperoxide
synthase 2 (PTGS2), solute carrier family 7 member 11 (SLC7A11), and acyl-CoA
synthetase long chain family member 4 (ACSL4) levels were evaluated.
Results: ARHGAP6 was obviously downregulated in cancer tissues and
cells. ARHGAP6 overexpression decreased cell proliferation, elevated cell death
and lipid ROS, decreased GPX4 and SLC7A11, increased PTGS2, ACSL4, and CHAC1, and
inhibited RhoA/ROCK1 and p38 MAPK signaling in cancer cells. ARHGAP6 knockdown
exerted opposite effects to those of ARHGAP6 overexpression. p38 signaling
suppression reversed the effect of ARHGAP6 knockdown on ferroptosis, while
RhoA/ROCK1 signaling inhibition compromised the effect of ARHGAP6 on p38 MAPK
signaling. In mice models, ARHGAP6 together with the ferroptosis inducer RSL3
cooperatively enhanced ferroptosis and inhibited tumor growth of cancer cells.
ARHGAP6 mRNA level was positively correlated with that of ferroptosis indicators
in tumor tissues. Conclusions: This study revealed that ARHGAP6
inhibited tumor growth of breast cancer by inducing ferroptosis via
RhoA/ROCK1/p38 MAPK signaling. Integrating ARHGAP6 with ferroptosis-inducing
agents may be a promising therapeutic strategy for breast cancer treatment.