2657 - tRNA-Derived Fragments and Radioresistance in Cervical Squamous Cell Carcinoma via SLC31A1 Mediated Cuproptosis
Presenter(s)
N. Wu1, and S. Jin2; 1Department of Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China, 2School of Public Health, NHC Key Laboratory of Radiobiology, Jilin University, Changchun, China
Purpose/Objective(s): Radiotherapy is a primary treatment for cervical squamous cell carcinoma (CSCC). However, the emergence of acquired radioresistance remains a major clinical obstacle that compromises therapeutic efficacy. tRNA-derived fragments (tRFs) have recently been recognized as functional non-coding RNAs involved in cancer progression and therapy resistance, while cuproptosis represents a newly defined copper-dependent form of regulated cell death. Whether and how tRFs regulate copper homeostasis and cuproptosis to influence radiosensitivity in CSCC remains unknown.
Materials/Methods: A radioresistant CSCC cell line (SiHa-RR) was established from parental SiHa cells through fractionated X-ray irradiation. Differentially expressed tRFs were identified by RNA sequencing. Cell viability, clonogenic survival, apoptosis, and radioresistance were evaluated using CCK-8 assays, colony formation assays, flow cytometry, and live–dead staining. Molecular mechanisms were investigated by qRT-PCR, Western blotting, dual-luciferase reporter assays, immunofluorescence, and intracellular copper and reactive oxygen species (ROS) measurements. The in vivo function of a candidate tRF was further validated using a nude mouse xenograft model.
Results: The SiHa-RR cells exhibited enhanced survival capacity, reduced apoptosis, and an attenuated DNA damage response following irradiation. Among dysregulated tRFs, AS-tDR-001098 (tRF-1098) was markedly upregulated in radioresistant cells. Mechanistically, tRF-1098 directly bound to and suppressed SLC31A1, which encodes the copper transporter 1 (CTR1). Ionizing radiation induced intracellular copper accumulation and activated cuproptosis in parental SiHa cells, as evidenced by increased ferredoxin 1 (FDX1) expression, dihydrolipoyl transacetylase (DLAT) lipoylation, and DLAT oligomerization, but these effects were blunted in SiHa-RR cells. Overexpression of tRF-1098 inhibited radiation-induced CTR1 upregulation and cuproptosis, thereby promoting radioresistance. Conversely, SLC31A1 overexpression sensitized CSCC cells to irradiation, an effect that was partially rescued by tRF-1098 co-overexpression. Consistently, tRF-1098 overexpression attenuated the antitumor efficacy of radiotherapy in vivo.
Conclusion: This study identifies tRF-1098 as a critical mediator of radioresistance in CSCC. By targeting the SLC31A1/CTR1, tRF-1098 suppresses copper influx and inhibits radiation-induced cuproptosis, thereby enabling tumor cell survival under radiotherapeutic stress. The tRF-1098/SLC31A1/cuproptosis pathway represents a previously unrecognized regulatory mechanism of radioresistance and provides potential molecular targets for improving radiotherapy efficacy in cervical cancer.