ESTRO 2025 - Abstract Book

S3991

Radiobiology - Tumour radiobiology

ESTRO 2025

2241

Digital Poster Carbon-ion radiotherapy inhibits lung cancer cell intravasation by regulating PGF methylation level Rui Li, Wei Chen, Mingying Xiao, Xuan Li, Ming Chen Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China Purpose/Objective: Compare to photon radiotherapy, carbon-ion radiotherapy has a better biological effectiveness, however the molecular mechanisms remain largely undiscovered. Material/Methods: We established a subcutaneous transplanted tumor model in C57BL/6J mice and treated with photon and carbon ion radiotherapy on the tumors. These tumor samples were collected and performed single cell RNA and TCR sequencing (scRNA-seq/scTCR-seq). By integrating analysis, we investigated the interactions between tumor cells and endothelial cells. Additionally, we performed bulk RNA sequencing and methylated RNA immunoprecipitation sequencing (MeRIP-seq) to explore the function of m 6 A on carbon-ion radiotherapy. Results: Integrative analyses of epithelial cells reveal a cancer cell cluster with high protein placental growth factor (PGF) expression was significantly decreased upon carbon-ion therapy, the hypoxic cancer cell cluster was known as PGF Overexpressing Hypoxic Cells (POHCs). POHCs had strong interactions with endothelial cells in the control samples and samples treated with photon radiotherapy, permitting intravasation into the bloodstream. The interaction between POHCs and endothelial cells in the samples with carbon-ion radiotherapy was significantly decreased. Mechanically, carbon-ion radiotherapy effectively killed POHCs and regulated the mRNA level of PGF in an m 6 A dependent manner. Conclusion: We have revealed the excellent killing effect of carbon-ion radiotherapy on hypoxic cancer cells and its huge potential for clinical application.

Keywords: Carbon-ion, lung cancer, PGF methylation level

2334

Proffered Paper A pan-cancer characterisation of the hypoxic extracellular matrix identifies a gene signature predictive of radiotherapy benefit Conrado Guerrero Quiles 1 , Julia Gonzalez Abalos 2 , A. S. Foussat 3 , Mark Reardon 1 , taha lodhi 1 , Vicky Smith 1 , Rekaya Shabbir 1 , Sapna Lunj 1 , Kim Reeves 1 , Alex Baker 4 , Michael Eyers 5 , Gayle Marshall 5 , Tim Smith 1 , Peter Hoskin 1 , Nicholas James 6 , Robert Huddart 6 , Emma Hall 6 , Nuria Porta 6 , Jonathan Humphries 7 , Martin Humphries 8 , Ananya Choudhury 1 , Catharine West 1 1 Cancer Sciences, University of Manchester, Manchester, United Kingdom. 2 immunity and cancer, Institute Curie, Paris, France. 3 Phonetics and Phonology, Sorbonne Nouvelle, Paris, France. 4 Manchester Institute, Cancer Research UK, Manchester, United Kingdom. 5 Medicines Discovery Catapult, Alderley Park, Manchester, United Kingdom. 6 Prostate and bladder cancer researc, The Institute of Cancer Research, London, United Kingdom. 7 Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom. 8 Welcome Centre for Matrix Research, University of Manchester, Manchester, United Kingdom