Biology subjects

Baulies, A.

Publications and source records attributed to Baulies, A..

4 recordsLinked to original sources

bioRxiv2024

SOX2 drives fetal reprogramming and reversible dormancy in colorectal cancer

Cellular plasticity plays critical roles in tissue regeneration, tumour progression and therapeutic resistance. However, the mechanism underlying this cell state transition remains elusive. Here, we show that the transcription factor SOX2 induces fetal reprogramming and reversible dormancy in colorectal cancer (CRC). SOX2 expression correlates with fetal reprogramming and poor prognosis in human primary and metastatic colorectal adenocarcinomas. In mouse CRC models, rare slow-cycling SOX2+SCA1+ cells are detected in early Apc-deleted mouse tumours that undergo slow clonal expansion over time. In contrast, the SOX2+ clones were found proliferative in advanced Apc-/-;KrasG12D/+;p53-/-;Tgfbr2-/-(AKPT) tumours, accompanied by dynamic cell state reprogramming from LGR5+ to LGR5-SCA1+ cells. Using transgenic mouse models, we demonstrate that ectopic expression of SOX2 inhibits intestinal lineage differentiation and induces fetal reprogramming. SOX2+ cells adopt dynamic cell cycle states depending on its expression level. High SOX2 expression results in hyperproliferation, whereas low SOX2 levels induce senescence-mediated dormancy. We find that loss of p53 can reverse SOX2-induced senescence, in line with the dormant cell state exit of the SOX2+ cells observed in advanced tumours. Finally, SOX2 expression is induced by 5-FU treatment in CRC. SOX2-expressing organoids exhibit increased tolerance to chemotherapy treatment, whilst deletion of SOX2 in AKPT tumour organoids sensitises drug responses. We propose that SOX2-induced plasticity and reversible dormancy promotes tumour progression and drug tolerance in CRC.

cancer biology↗

bioRxiv2023

ARID3A coordinates the proliferation-differentiation switch of transit-amplifying cells in the intestine

Intestinal stem cells (ISCs) at the crypt base divide and give rise to progenitor cells that have the capacity to proliferate and differentiate into various mature epithelial cell types in the transit-amplifying (TA) zone. Here, we identified the transcription factor ARID3A as a novel regulator of intestinal epithelial cell proliferation and differentiation at the TA compartment. We show that ARID3A forms an expression gradient from villus tip to the early progenitors at the crypts mediated by TGF-{beta} and WNT signalling. Intestinal epithelial-specific deletion of Arid3a reduces proliferation of TA cells. Bulk and single cell transcriptomic analysis shows increased enterocyte differentiation and reduced secretory cells in the Arid3a cKO intestine. Interestingly, upper-villus gene signatures of both enterocytes and secretory cells are enriched in the mutant intestine. We find that the enhanced enterocyte differentiation in the Arid3a cKO intestine is caused by increased binding of HNF1 and HNF4. Finally, we show that loss of Arid3a impairs irradiation-induced regenerative process by altering the dynamics of proliferation and apoptosis. Our findings imply that ARID3A may play a gatekeeping role in the TA compartment to maintain the "just-right" proliferation-to-differentiation ratio for tissue homeostasis and plasticity.

developmental biology↗

bioRxiv2022

USP7 inactivation suppresses APC-mutant intestinal hyperproliferation and tumor development

Truncating mutation of the tumor suppressor gene adenomatous polyposis coli (APC) is the hallmark of colorectal cancer (CRC), resulting in constitutive WNT activation. Despite decades of research, targeting WNT signaling in cancer remains challenging due to its essential role in normal stem cell maintenance. We have previously shown that the deubiquitinating enzyme USP7 is a tumor-specific WNT activator in APC-truncated cells by deubiquitinating and stabilizing {beta}-catenin, but its role in gut tumorigenesis is unknown. Here we show in vivo that deletion of Usp7 in Apc-truncated mice inhibits crypt hyperproliferation and intestinal tumor development. Importantly, intestine-specific Usp7 mutation does not yield any phenotype in wildtype animals, indicating that its loss is well tolerated. Unexpectedly, prolonged deletion of Usp7 in Apc+/- intestine induces varying degrees of colitis. Treatment with a USP7 inhibitor suppresses growth of patient-derived cancer organoids in vitro and of xenografts carrying APC truncations. We propose that USP7 inhibition may be efficacious for tumor-specific therapy of sporadic APC-mutated CRC, while patients with germline APC mutations should not receive such treatment. HighlightsO_LIUsp7 deletion in Apc-truncated mice reduces intestinal tumor development. C_LIO_LIIntestine-specific Usp7 mutation mutation has no phenotype in wildtype animals. C_LIO_LITreatment with Usp7 inhibitor suppresses growth of patient-derived cancer organoids carrying Apc truncations in vitro and of xenografts. C_LI

cancer biology↗

bioRxiv2019

Engineering transplantable jejunal mucosal grafts using primary patient-derived organoids from children with intestinal failure

Intestinal failure (IF), following extensive anatomical or functional loss of small intestine (SI), has debilitating long-term effects on infants and children with this condition. Priority of care is to increase the childs length of functional intestine, jejunum in particular, to improve nutritional independence. Here we report a robust protocol for reconstruction of autologous intestinal mucosal grafts using primary IF patient materials. Human jejunal intestinal organoids derived from paediatric IF patients can be expanded efficiently in vitro with region-specific markers preserved after long-term culture. Decellularized human intestinal matrix with intact ultrastructure is used as biological scaffolds. Proteomic and Raman spectroscopic analyses reveal highly analogous biochemical composition of decellularized human SI and colon matrix, implying that they can both be utilised as scaffolds for jejunal graft reconstruction. Indeed, seeding of primary human jejunal organoids to either SI or colonic scaffolds in vitro can efficiently reconstruct functional jejunal grafts with persistent disaccharidase activity as early as 4 days after seeding, which can further survive and mature after transplantation in vivo. Our findings pave the way towards regenerative medicine for IF patients.

bioengineering↗