bims-instec 2024-11-10 papers

Issue of 2024‒11‒10
two papers selected by
Maria-Virginia Giolito, Université Catholique de Louvain

Development. 2024 Nov 05. pii: dev.202941. [Epub ahead of print]

Lgr5+ intestinal stem cells are required for organoid survival after genotoxic injury.

Joseph Lee, Antoine Gleizes, Nicolas V Janto, Lito L Appell, Siyang Sun, Felipe Takaesu, Sarah F Webster, Taylor Hailstock, Nick Barker, Adam D Gracz.

Progenitors and mature cells can maintain the intestinal epithelium by dedifferentiation and facultative intestinal stem cell (fISC) function when active ISCs (aISCs) are lost to damage. Here, we modeled fISC activation in intestinal organoids with doxorubicin (DXR), a chemotherapeutic known to ablate Lgr5+ aISCs in vivo. Similar fISC gene activation was observed between organoids treated with low vs high DXR, despite significantly decreased survival at the higher dose. aISCs exhibit dose-dependent loss after DXR but survive at doses compatible with organoid survival. We ablated residual aISCs after DXR using a Lgr52A-DTR allele and observed that aISC survival of the initial genotoxic insult is required for organoid survival following DXR. These results suggest that while typical fISC genes are activated by DXR injury in organoids, functional stemness remains dependent on the aISC pool. Finally, we show that human intestinal organoids require higher doses of DXR to induce loss of survival and downregulation of LGR5. Our data establish a reproducible model of DXR injury in intestinal organoids and reveal differences in in vitro responses to an established in vivo damage modality.

Keywords: Doxorubicin; Intestinal stem cells; Organoids; Regeneration

DOI: https://doi.org/10.1242/dev.202941

Nat Cancer. 2024 Nov 01.

Recapitulating the adenoma-carcinoma sequence by selection of four spontaneous oncogenic mutations in mismatch-repair-deficient human colon organoids.

Tomohiro Mizutani, Matteo Boretto, Sangho Lim, Jarno Drost, Diego Montiel González, Rurika Oka, Maarten H Geurts, Harry Begthel, Jeroen Korving, Johan H van Es, Ruben van Boxtel, Hans Clevers.

Carcinogenesis results from the sequential acquisition of oncogenic mutations that convert normal cells into invasive, metastasizing cancer cells. Colorectal cancer exemplifies this process through its well-described adenoma-carcinoma sequence, modeled previously using clustered regularly interspaced short palindromic repeats (CRISPR) to induce four consecutive mutations in wild-type human gut organoids. Here, we demonstrate that long-term culture of mismatch-repair-deficient organoids allows the selection of spontaneous oncogenic mutations through the sequential withdrawal of Wnt agonists, epidermal growth factor (EGF) agonists and the bone morphogenetic protein (BMP) antagonist Noggin, while TP53 mutations were selected through the addition of Nutlin-3. Thus, organoids sequentially acquired mutations in AXIN1 and AXIN2 (Wnt pathway), TP53, ACVR2A and BMPR2 (BMP pathway) and NRAS (EGF pathway), gaining complete independence from stem cell niche factors. Quadruple-pathway (Wnt, EGF receptor, p53 and BMP) mutant organoids formed solid tumors upon xenotransplantation. This demonstrates that carcinogenesis can be recapitulated in a DNA repair-mutant background through in vitro selection that targets four consecutive cancer pathways.

DOI: https://doi.org/10.1038/s43018-024-00841-x