# Disrupting Lipid Raft Microdomains to Block Polyploid Giant Cancer Cell Budding and Enhance Radiotherapy Response

## TL;DR

Blocking lipid raft structures in cancer cells can prevent tumor regrowth after radiation therapy and improve treatment outcomes.

## Contribution

The discovery of a SNCG–FLOT2–CHMP4B signaling axis in lipid rafts regulating PGCC budding and its disruption to enhance radiotherapy.

## Key findings

- PGCCs regenerate tumors via budding regulated by a SNCG–FLOT2–CHMP4B axis in lipid rafts.
- Disrupting lipid rafts with statins or anti-PCSK9 antibodies blocks budding and improves radiotherapy response.
- Lipid raft disruption suppresses tumor repopulation and increases radiosensitivity in models.

## Abstract

Radiotherapy failure often arises from tumor repopulation by treatment‐resistant cancer cells. Following irradiation, cancer cells can undergo endoreplication to form polyploid giant cancer cells (PGCCs)—radiation‐persistent cells capable of generating progeny through a virus‐like asymmetric budding process. While such membrane budding is evolutionarily conserved across archaea, viruses, and eukaryotic cells, its molecular mechanism in cancer remains poorly defined. Here, a radiation‐induced SNCG–FLOT2–CHMP4B signaling axis is identified as a key regulator of PGCC budding. Mechanistically, ASAH1 and SMPD2 maintain sphingolipid metabolic balance, while FLOT2 drives germination at lipid raft–enriched membrane microdomains, followed by CHMP4B‐dependent abscission to release daughter cells. Disrupting these lipid raft structures—via statins or anti‐PCSK9 antibodies—impairs budding, suppresses PGCC‐derived tumor repopulation, and enhances radiosensitivity in vitro and in vivo. This findings uncover a conserved membrane remodeling program underlying PGCC budding and establish lipid raft disruption as a promising therapeutic approach to prevent tumor recurrence after radiotherapy. Clinically available lipid‐lowering agents may thus serve as innovative radiosensitizers to improve radiotherapy outcomes.

Radiation induces polyploid giant cancer cells (PGCCs) that regenerate tumors through virus‐like budding. This process depends on a SNCG–FLOT2–CHMP4B signaling axis functioning in lipid raft microdomains. Disrupting these domains using statins or anti‐PCSK9 antibodies blocks PGCC budding, suppresses tumor repopulation, and enhances radiotherapy efficacy in vitro and in vivo.