bims-instec Biomed News
on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration
Issue of 2022‒08‒28
four papers selected by
Maria-Virginia Giolito

  1. Cell Stem Cell. 2022 Aug 19. pii: S1934-5909(22)00338-1. [Epub ahead of print]
      Opposing roles have been proposed for IL-22 in intestinal pathophysiology. We have optimized human small intestinal organoid (hSIO) culturing, constitutively generating all differentiated cell types while maintaining an active stem cell compartment. IL-22 does not promote the expansion of stem cells but rather slows the growth of hSIOs. In hSIOs, IL-22 is required for formation of Paneth cells, the prime producers of intestinal antimicrobial peptides (AMPs). Introduction of inflammatory bowel disease (IBD)-associated loss-of-function mutations in the IL-22 co-receptor gene IL10RB resulted in abolishment of Paneth cells in hSIOs. Moreover, IL-22 induced expression of host defense genes (such as REG1A, REG1B, and DMBT1) in enterocytes, goblet cells, Paneth cells, Tuft cells, and even stem cells. Thus, IL-22 does not directly control the regenerative capacity of crypt stem cells but rather boosts Paneth cell numbers, as well as the expression of AMPs in all cell types.
    Keywords:  IL-22; IL10RB; Paneth cells; anti-microbial proteins; enterocytes; inflammatory bowel disease; intestinal stem cells; mTOR; organoids; regeneration
  2. Br J Cancer. 2022 Aug 23.
      BACKGROUND: Colorectal cancer (CRC), the most common cancer type, causes high morbidity and mortality. Patients who develop drug resistance to oxaliplatin-based regimens have short overall survival. Thus, identifying molecules involved in the development of oxaliplatin resistance is critical for designing therapeutic strategies.METHODS: A proteomic screen was performed to reveal altered protein kinase phosphorylation in oxaliplatin-resistant (OR) CRC tumour spheroids. The function of CHK2 was characterised using several biochemical techniques and evident using in vitro cell and in vivo tumour models.
    RESULTS: We revealed that the level of phospho-CHK2(Thr68) was elevated in OR CRC cells and in ~30% of tumour samples from patients with OR CRC. We demonstrated that oxaliplatin activated several phosphatidylinositol 3-kinase-related kinases (PIKKs) and CHK2 downstream effectors and enhanced CHK2/PARP1 interaction to facilitate DNA repair. A phosphorylation mimicking CHK2 mutant, CHK2T68D, but not a kinase-dead CHK2 mutant, CHK2D347A, promoted DNA repair, the CHK2/PARP1 interaction, and cell growth in the presence of oxaliplatin. Finally, we showed that a CHK2 inhibitor, BML-277, reduced protein poly(ADP-ribosyl)ation (PARylation), FANCD2 monoubiquitination, homologous recombination and OR CRC cell growth in vitro and in vivo.
    CONCLUSION: Our findings suggest that CHK2 activity is critical for modulating oxaliplatin response and that CHK2 is a potential therapeutic target for OR CRC.
  3. Nat Commun. 2022 Aug 20. 13(1): 4913
      The treatment of colorectal cancer (CRC) is an unmet medical need in absence of early diagnosis. Here, upon characterizing cancer-specific transposable element-driven transpochimeric gene transcripts (TcGTs) produced by this tumor in the SYSCOL cohort, we find that expression of the hominid-restricted retrogene POU5F1B through aberrant activation of a primate-specific endogenous retroviral promoter is a strong negative prognostic biomarker. Correlating this observation, we demonstrate that POU5F1B fosters the proliferation and metastatic potential of CRC cells. We further determine that POU5F1B, in spite of its phylogenetic relationship with the POU5F1/OCT4 transcription factor, is a membrane-enriched protein that associates with protein kinases and known targets or interactors as well as with cytoskeleton-related molecules, and induces intracellular signaling events and the release of trans-acting factors involved in cell growth and cell adhesion. As POU5F1B is an apparently non-essential gene only lowly expressed in normal tissues, and as POU5F1B-containing TcGTs are detected in other tumors besides CRC, our data provide interesting leads for the development of cancer therapies.
  4. J Oncol. 2022 ;2022 6367437
      Colorectal cancer (CRC) is significantly correlated with inflammatory bowel disease, which usually manifests as chronic relapsing-remitting colitis. Phosphofructo-2-kinase/fructose-2,6-biophosphatase 3 (PFKFB3) can catalyze to produce fructose-2,6-bisphosphate and function as an oncogene. In this study, we revealed the function of PFKFB3 in colitis-associated CRC (CAC) and the potential mechanism. RT-qPCR and Western blot were utilized to detect the level of PFKFB3 expression. Increased PFKFB3 expression was observed in the mouse CAC model and CAC patient samples. We identified that overexpression of PFKFB3 in intestinal epithelial cells (IECs) could increase the proliferation, migration, and invasion of CRC cells by the coculture system. Mechanistically, overexpression of PFKFB3 induced phospho-p65 and promoted the expression of IL-1β and tumor necrosis factor alpha (TNF-α) in the development of colitis and CAC. In addition, PFK158, the PFKFB3 inhibitor, could reduce the CRC cell viability, migration, and invasion caused by PFKFB3 overexpression. In conclusion, overexpression of PFKFB3 promoted tumorigenesis in CAC by inducing phospho-p65 and expression of IL-1β and TNF-α. Our study suggested that PFKFB3 acted as a potential treatment target for CAC.