Stastna, M. | bioRxiv Science

bioRxiv2022

Terminal differentiation of enterocytes is governed by distinct members of Tgfβ superfamily

The protective and absorptive functions of the intestinal epithelium rely on differentiated enterocytes in the villi. The differentiation of enterocytes is orchestrated by sub-epithelial mesenchymal cells producing distinct ligands along the villus axis, in particular Bmps and Tgf{beta}. Here we show that individual Bmp ligands and Tgf{beta} drive distinct enterocytic programs specific to villus zonation. Bmp4 is expressed mainly from the center to the upper part of the villus, and it activates preferentially genes connected to lipid uptake and metabolism. In contrast, Bmp2 is produced by villus-tip mesenchymal cells, and it influences the adhesive properties of villus-tip epithelial cells and the expression of immunomodulators. Hence, Bmp2 promotes the terminal enterocytic differentiation at the villus-tip. Additionally, Tgf{beta} induces epithelial gene expression programs similar to that triggered by Bmp2. The inhibition of Bmp receptor type I in vivo and using intestinal organoids lacking Smad4 revealed that Bmp2-driven villus-tip program is activated by a canonical Smad-dependent mechanism. Finally, we established an organoid cultivation system that enriches for villus-tip enterocytes and thereby better mimics the cellular composition of the intestinal epithelium. Altogether our data suggest that not only Bmp gradient, but also the activity of individual Bmp drives specific enterocytic programs.

cell biology↗

bioRxiv2022

TROP2 represents a negative prognostic factor in colorectal adenocarcinoma and its expression is associated with features of epithelial-mesenchymal transition and invasiveness

Trophoblastic cell surface antigen 2 (TROP2) is a membrane glycoprotein overexpressed in many solid tumors with poor prognosis, including intestinal neoplasms. In our study, we show that TROP2 is expressed in preneoplastic lesions and its expression is maintained in most colorectal cancer (CRC). High TROP2 positivity correlated with lymph node metastases and poor tumor differentiation and was a negative prognostic factor. To investigate the role of TROP2 in intestinal tumors, we analyzed two mouse models with conditional disruption of the adenomatous polyposis coli (Apc) tumor suppressor gene, human adenocarcinoma samples, patient-derived organoids, and TROP2-deficient tumor cells. We found that Trop2 is produced early after Apc inactivation and its expression is associated with transcription of genes involved in epithelial-mesenchymal transition, regulation of migration, invasiveness, and extracellular matrix remodeling. A functionally similar group of genes was also enriched in TROP2-positive cells from human CRC samples. To decipher the driving mechanism of TROP2 expression, we analyzed its promoter. In human cells, this promoter was activated by {beta}-catenin and additionally by Yes1-associated transcriptional regulator (YAP). The regulation of TROP2 expression by active YAP was verified by YAP knockdown in CRC cells. Our results suggest a possible link between aberrantly activated Wnt/{beta}-catenin signaling, YAP, and TROP2 expression. Simple SummaryColorectal cancer (CRC) is one of the most common cancers worldwide. While systemic treatment of CRC is based on chemotherapy, subsequent therapeutic options are far less effective. Trophoblast cell surface antigen 2 (TROP2) is highly expressed in many carcinomas, including CRC, where its expression correlates with poor prognosis. Anti-TROP2-targeted therapy was approved for the treatment of breast and urothelial carcinomas. We aimed to determine whether TROP2 is a suitable target for the treatment of CRC. We demonstrated that TROP2 expression in CRC correlates with lymph node metastasis and poor tumor differentiation. Analysis of mouse tumor models, patient-derived organoids, and tumor cells revealed that TROP2 expression is associated with features related to epithelial-mesenchymal transition and invasiveness. Our results suggest that TROP2 targeting may be a promising approach, especially in the early phase of treatment.

cancer biology↗