bims-instec Biomed News
on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration
Issue of 2022‒04‒10
nine papers selected by
Maria-Virginia Giolito

  1. Sci Rep. 2022 Apr 02. 12(1): 5569
      The intestinal epithelium is one of the fastest renewing tissues in mammals. It shows a hierarchical organisation, where intestinal stem cells at the base of crypts give rise to rapidly dividing transit amplifying cells that in turn renew the pool of short-lived differentiated cells. Upon injury and stem-cell loss, cells can also de-differentiate. Tissue homeostasis requires a tightly regulated balance of differentiation and stem cell proliferation, and failure can lead to tissue extinction or to unbounded growth and cancerous lesions. Here, we present a two-compartment mathematical model of intestinal epithelium population dynamics that includes a known feedback inhibition of stem cell differentiation by differentiated cells. The model shows that feedback regulation stabilises the number of differentiated cells as these become invariant to changes in their apoptosis rate. Stability of the system is largely independent of feedback strength and shape, but specific thresholds exist which if bypassed cause unbounded growth. When dedifferentiation is added to the model, we find that the system can recover faster after certain external perturbations. However, dedifferentiation makes the system more prone to losing homeostasis. Taken together, our mathematical model shows how a feedback-controlled hierarchical tissue can maintain homeostasis and can be robust to many external perturbations.
  2. Stem Cell Reports. 2022 Apr 06. pii: S2213-6711(22)00140-0. [Epub ahead of print]
      NOTCH signaling is a key regulator involved in maintaining intestinal stem cell (ISC) homeostasis and for balancing differentiation. Using single-cell transcriptomics, we observed that OLFM4, a NOTCH target gene present in ISCs, is first expressed at 13 weeks post-conception in the developing human intestine and increases over time. This led us to hypothesize that the requirement for NOTCH signaling is acquired across human development. To test this, we established a series of epithelium-only organoids (enteroids) from different developmental stages and used γ-secretase inhibitors (dibenzazepine [DBZ] or DAPT) to functionally block NOTCH signaling. Using quantitative enteroid-forming assays, we observed a decrease in enteroid forming efficiency in response to γ-secretase inhibition as development progress. When DBZ was added to cultures and maintained during routine passaging, enteroids isolated from tissue before 20 weeks had higher recovery rates following single-cell serial passaging. Finally, bulk RNA sequencing (RNA-seq) analysis 1 day and 3 days after DBZ treatment showed major differences in the transcriptional changes between developing or adult enteroids. Collectively, these data suggest that ISC dependence on NOTCH signaling increases as the human intestine matures.
    Keywords:  NOTCH; enteroid; intestinal stem cell; intestine; organoid
  3. BMC Cancer. 2022 Apr 04. 22(1): 363
      Radio-chemotherapy with 5-flu orouracil (5-FU) is the standard of care treatment for patients with colorectal cancer, but it is only effective for a third of them. Despite our understanding of the mechanism of action of 5-FU, drug resistance remains a significant limitation to the clinical use of 5-FU, as both intrinsic and acquired chemoresistance represents the major obstacles for the success of 5-FU-based chemotherapy. In order to identify the mechanism of acquired resistance, 5-FU chemoresistance was induced in CRC cell lines by passaging cells with increasing concentrations of 5-FU. To study global molecular changes, quantitative proteomics and transcriptomics analyses were performed on these cell lines, comparing the resistant cells as well as the effect of chemo and radiotherapy. Interestingly, a very high proportion of downregulated genes were annotated as transcription factors coding for Krüppel-associated box (KRAB) domain-containing zinc-finger proteins (KZFPs), the largest family of transcriptional repressors. Among nearly 350 KRAB-ZFPs, almost a quarter were downregulated after the induction of a 5-FU-resistance including a common one between the three CRC cell lines, ZNF649, whose role is still unknown. To confirm the observations of the proteomic and transcriptomic approaches, the abundance of 20 different KZFPs and control mRNAs was validated by RT-qPCR. In fact, several KZFPs were no longer detectable using qPCR in cell lines resistant to 5-FU, and the KZFPs that were downregulated only in one or two cell lines showed similar pattern of expression as measured by the omics approaches. This proteomic, transcriptomic and genomic analysis of intrinsic and acquired resistance highlights a possible new mechanism involved in the cellular adaptation to 5-FU and therefore identifies potential new therapeutic targets to overcome this resistance.
    Keywords:  5-fluorouracil; Cancer omics; Chemotherapy; Colorectal cancer; DNA damage; Drug resistance mechanisms; Radiation therapy
  4. Mol Cancer Res. 2022 Apr 08. pii: molcanres.MCR-21-0994-A.2021. [Epub ahead of print]
      KRAS mutation in colorectal cancer (CRC) is associated with aggressive tumor behavior through increased invasiveness and higher rates of lung metastases, but the biological mechanisms behind these features are not fully understood. In this study, we show that KRAS mutant CRC upregulates integrin α6β4 through ERK/MEK signaling. Knocking-out integrin β4 specifically depleted the expression of integrin α6β4 and this resulted in a reduction in the invasion and migration ability of the cancer cells. We also observed a reduction in the number and area of lung metastatic foci in mice that were injected with integrin β4 knock-out KRAS mutant CRC cells compared to the mice injected with integrin β4 wild-type KRAS mutant CRC cells, while no difference was observed in liver metastases. Inhibiting integrin α6β4 in KRAS mutant CRC could be a potential therapeutic target to diminish the KRAS invasive phenotype and associated pulmonary metastasis rate. Implications: Knocking-out Integrin β4 (ITGB4), which is overexpressed in KRAS mutant colorectal cancer and promotes tumor aggressiveness, diminishes local invasiveness and rates of pulmonary metastasis.
  5. Cancer Cell Int. 2022 Apr 02. 22(1): 142
      PURPOSE: 5-fluorouracil (5-FU), an effective chemotherapy drug, is commonly applied for colorectal cancer treatment. Nevertheless, its toxicity to normal tissues and the development of tumor resistance are the main obstacles to successful cancer chemotherapy and hence, its clinical application is limited. The use of resveratrol can increase 5-FU-induced cytotoxicity and mitigate the unwanted adverse effects. This study aimed to review the potential therapeutic effects of resveratrol in combination with 5-FU against colorectal cancer.METHODS: According to the PRISMA guideline, a comprehensive systematic search was carried out for the identification of relevant literature in four electronic databases of PubMed, Web of Science, Embase, and Scopus up to May 2021 using a pre-defined set of keywords in their titles and abstracts. We screened 282 studies in accordance with our inclusion and exclusion criteria. Thirteen articles were finally included in this systematic review.
    RESULTS: The in vitro findings showed that proliferation inhibition of colorectal cancer cells in the groups treated by 5-FU was remarkably higher than the untreated groups and the co-administration of resveratrol remarkably increased cytotoxicity induced by 5-FU. The in vivo results demonstrated a decrease in tumor growth of mice treated by 5-FU than the untreated group and a dramatic decrease was observed following combined treatment of resveratrol and 5-FU. It was also found that 5-FU alone and combined with resveratrol could regulate the cell cycle profile of colorectal cancer cells. Moreover, this chemotherapeutic agent induced the biochemical and histopathological changes in the cancerous cells/tissues and these alterations were synergized by resveratrol co-administration (for most of the cases), except for the inflammatory mediators.
    CONCLUSION: The results obtained from this systematic review demonstrated that co-administration of resveratrol could sensitize the colorectal cancer cells to 5-FU treatment via various mechanisms, including regulation of cell cycle distribution, oxidant, apoptosis, anti-inflammatory effects.
    Keywords:  5-fluorouracil; Chemotherapy; Colorectal cancer; Resveratrol; Systemic review
  6. Cell Death Dis. 2022 Apr 05. 13(4): 303
      Oxaliplatin resistance is a major challenge in the treatment of colorectal cancer (CRC). Many molecular targeted drugs for refractory CRC have been developed to solve CRC drug resistance, but their effectiveness and roles in the progression of CRC and oxaliplatin resistance remain unclear. Here, we successfully constructed CRC PDOs and selected the Kruppel-like factor 5 (KLF5) inhibitor ML264 as the research object based on the results of the in vitro drug screening assay. ML264 significantly restored oxaliplatin sensitivity in CRC PDOs by restoring the apoptotic response, and this effect was achieved by inhibiting the KLF5/Bcl-2/caspase3 signaling pathway. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays verified that KLF5 promoted the transcription of Bcl-2 in CRC cells. KLF5 inhibition also overcame oxaliplatin resistance in xenograft tumors. Taken together, our study demonstrated that ML264 can restore oxaliplatin sensitivity in CRC PDOs by restoring the apoptotic response. KLF5 may be a potential therapeutic target for oxaliplatin-resistant CRC. PDOs have a strong potential for evaluating inhibitors and drug combination therapy in a preclinical environment.
  7. Biochem Biophys Res Commun. 2022 Mar 27. pii: S0006-291X(22)00484-3. [Epub ahead of print]607 81-88
      Vacuolar protein sorting-associated protein 16 homolog (VPS16) is a central member of the VPS core complex (VPS-C) and is reported to function as a tether protein involved in membrane fusion. However, a biological role for VPS16 in tumors remains largely unknown. Herein, we demonstrated that VPS16 was overexpressed in colorectal cancer (CRC) as revealed by qRT-PCR, western blotting, and immunohistochemical analyses. Elevated expression of VPS16 was positively correlated with tumor size and TNM stage, and Kaplan-Meier analysis showed an association between VPS16 and survival in CRC patients. Downregulation of endogenous VPS16 significantly suppressed CRC cell viability both in vitro and vivo; and while our mechanistic analysis showed that VPS16 depletion induced autophagy, but the autophagic flow was deficient as reflected by the inhibition of autolysosomal maturation. Overexpression of VPS16 also mediated oxaliplatin (OX) resistance by promoting the maturation of autolysosomes in CRC. VPS16 may therefore promote cell survival and thus serve as a useful target for cancer therapy in CRC.
    Keywords:  Autolysosomal maturation; Chemoresistance; Colorectal cancer; VPS16
  8. Nat Commun. 2022 Apr 05. 13(1): 1827
      The aryl hydrocarbon receptor (AHR) is an environmental sensor that integrates microbial and dietary cues to influence physiological processes within the intestinal microenvironment, protecting against colitis and colitis-associated colorectal cancer development. Rapid tissue regeneration upon injury is important for the reinstatement of barrier integrity and its dysregulation promotes malignant transformation. Here we show that AHR is important for the termination of the regenerative response and the reacquisition of mature epithelial cell identity post injury in vivo and in organoid cultures in vitro. Using an integrative multi-omics approach in colon organoids, we show that AHR is required for timely termination of the regenerative response through direct regulation of transcription factors involved in epithelial cell differentiation as well as restriction of chromatin accessibility to regeneration-associated Yap/Tead transcriptional targets. Safeguarding a regulated regenerative response places AHR at a pivotal position in the delicate balance between controlled regeneration and malignant transformation.
  9. Nat Commun. 2022 Apr 04. 13(1): 1798
      The evolutionary dynamics of tumor initiation remain undetermined, and the interplay between neoplastic cells and the immune system is hypothesized to be critical in transformation. Colorectal cancer (CRC) presents a unique opportunity to study the transition to malignancy as pre-cancers (adenomas) and early-stage cancers are frequently resected. Here, we examine tumor-immune eco-evolutionary dynamics from pre-cancer to carcinoma using a computational model, ecological analysis of digital pathology data, and neoantigen prediction in 62 patient samples. Modeling predicted recruitment of immunosuppressive cells would be the most common driver of transformation. As predicted, ecological analysis reveals that progressed adenomas co-localized with immunosuppressive cells and cytokines, while benign adenomas co-localized with a mixed immune response. Carcinomas converge to a common immune "cold" ecology, relaxing selection against immunogenicity and high neoantigen burdens, with little evidence for PD-L1 overexpression driving tumor initiation. These findings suggest re-engineering the immunosuppressive niche may prove an effective immunotherapy in CRC.