Hutvagner, G. | bioRxiv Science

bioRxiv2026

Lipid nanoparticle-mediated RNAi targeting of KRAS mutants sensitises colorectal cancer cells to chemotherapy

KRAS mutations, including G12D, G12V and G13D, are major oncogenic drivers in colorectal cancer (CRC) and are associated with therapeutic resistance. However, approved KRAS inhibitors remain focused on G12C subtype, leaving these prevalent variants without approved targeted therapies. Here, we developed a lipid nanoparticle (LNP)-based RNA interference (RNAi) strategy to target these three KRAS variants using a single small interfering RNA (siRNA) sequence. The developed siRNA-LNPs reduced KRAS mRNA and protein expression in HCT116 (G13D), SW620 (G12V) and LS180 (G12D) cells, but not in KRAS wild-type HT29 cells, suppressing the cellular proliferation, clonogenic survival and migration. Transcriptomic profiling revealed changes in KRAS associated signalling, including suppression of cell-cycle and DNA repair programmes, providing a rationale for combining siRNA silencing with the fluoropyrimidine chemotherapeutic agent 5-fluorouracil (5-FU). The combination produced synergistic effects across all three KRAS-mutant CRC cell models and enhanced the apoptosis in both monolayer cultures and 3D spheroids. Collectively, these findings provide proof of concept for this combination strategy and support its further investigation as a potential therapeutic approach for KRAS-mutant CRC.

molecular biology↗

bioRxiv2018

A cell cycle-coordinated nuclear compartment for Polymerase II transcription encompasses the earliest gene expression before global genome activation

Most metazoan embryos commence development with rapid cleavages without zygotic gene expression and their genome activation is delayed until the mid-blastula transition (MBT). However, a set of genes escape global repression during the extremely fast cell cycles, which lack gap phases and their transcription is activated before the MBT. Here we describe the formation and the spatio-temporal dynamics of a distinct transcription compartment, which encompasses the earliest detectable transcription during the first wave of genome activation. Simultaneous 4D imaging of expression of pri-miR430 and zinc finger genes by a novel, native transcription imaging approach reveals a pair of shared transcription compartments regulated by homolog chromosome organisation. These nuclear compartments carry the majority of nascent RNAs and transcriptionally active Polymerase II, are depleted of compact chromatin and represent the main sites for detectable transcription before MBT. We demonstrate that transcription occurs in the S-phase of the cleavage cycles and that the gradual slowing of these cell cycles are permissive to transcription before global genome activation. We propose that the demonstrated transcription compartment is part of the regulatory architecture of nucleus organisation, and provides a transcriptionally competent, supporting environment to facilitate early escape from the general nuclear repression before global genome activation.

developmental biology↗