bims-instec Biomed News
on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration
Issue of 2022‒09‒18
24 papers selected by
Maria-Virginia Giolito
Free University of Brussels

  1. J Exp Med. 2022 Nov 07. pii: e20212405. [Epub ahead of print]219(11):
      Intestinal epithelium regenerates rapidly through proliferation of intestinal stem cells (ISCs), orchestrated by potent mitogens secreted within the crypt niche. However, mechanisms regulating these mitogenic factors remain largely unknown. Here, we demonstrate that transit-amplifying (TA) cells, marked by unconventional prefoldin RPB5 interactor (URI), control R-spondin production to guide ISC proliferation. Genetic intestinal URI ablation in mice injures TA cells, reducing their survival capacity, leading to an inflamed tissue and subsequently decreasing R-spondin levels, thereby causing ISC quiescence and disruption of intestinal structure. R-spondin supplementation or restoration of R-spondin levels via cell death inhibition by c-MYC elimination or the suppression of inflammation reinstates ISC proliferation in URI-depleted mice. However, selective c-MYC and p53 suppression are required to fully restore TA cell survival and differentiation capacity and preserve complete intestinal architecture. Our data reveal an unexpected role of TA cells, which represent a signaling platform instrumental for controlling inflammatory cues and R-spondin production, essential for maintaining ISC proliferation and tissue regeneration.
  2. Front Genet. 2022 ;13 962575
      Colorectal cancer (CRC) is one of the most common malignant tumors with a high incidence rate and mortality. LncRNA is an important regulator of the immune system. It is of great significance to study immune-related lncRNAs (IR-lncRNAs) for CRC. In this study, we screened IR-lncRNAs differentially expressed in normal and CRC tissues, and Univariate Cox regression and the Least Absolute Shrinkage and Selection Operator were applied to construct IR-lncRNA prognostic signature in TCGA training dataset, and its predictive capability for the prognosis of CRC patients was verified in GSE39582 validation dataset. The novel signature was identified as an independent predictor of prognosis in CRC patients. In addition, the signature could accurately predict the feature of the immune microenvironment and therapeutic response in CRC patients. The CMap database was adopted to screen for small molecule candidate drugs that can reverse and treat high-risk CRC patients. Finally, the expression of six IR-lncRNAs were verified by qRT-PCR in clinical specimens from our patient cohort. In conclusion, we construct an IR-lncRNA prognostic signature, which is a powerful biomarker of CRC and can accurately predict the prognosis, immune microenvironment feature, and therapeutic response of CRC patients.
    Keywords:  candidate drugs; colorectal cancer; immune signature; long non-coding RNA; prognosis; qRT-PCR; therapeutic response; tumor immune microenvironment
  3. ACS Pharmacol Transl Sci. 2022 Sep 09. 5(9): 724-734
      Drug resistance is a leading cause for the failure of cancer treatments. Plasticity of cancer cells to acquire stem cell-like properties enables them to escape drug toxicity through different adaptive mechanisms. Eliminating cancer stem cells (CSCs) can potentially improve treatment outcomes for patients. To determine the role of CSCs in resistance of colorectal cancer cells to targeted therapies and identify treatment strategies, we treated spheroids of BRAFmut and KRASmut colorectal cancer cells with inhibitors of the mitogen-activated protein kinase pathway and studied resistance mechanisms through gene and protein expression analyses. We found that treatments activated several oncogenic pathways and expression of CSC markers CD166 and ALDH1A3. We identified a specific combination treatment using trametinib and mithramycin A to simultaneously inhibit the CSC phenotype and activities of several pathways in cancer cells. This study demonstrates the feasibility of therapeutic targeting of CSCs as a strategy to block tumorigenic activities of cancer cells.
  4. Elife. 2022 Sep 12. pii: e78837. [Epub ahead of print]11
      The establishment and maintenance of different cellular compartments in tissues is a universal requirement across all metazoans. Maintaining the correct ratio of cell types in time and space allows tissues to form patterned compartments and perform complex functions. Patterning is especially evident in the human colon, where tissue homeostasis is maintained by stem cells in crypt structures that balance proliferation and differentiation. Here, we developed a human 2D patient derived organoid (PDO) screening platform to study tissue patterning and kinase pathway dynamics in single cells. Using this system, we discovered that waves of ERK signaling induced by apoptotic cells play a critical role in maintaining tissue patterning and homeostasis. If ERK is activated acutely across all cells instead of in wavelike patterns, then tissue patterning and stem cells are lost. Conversely, if ERK activity is inhibited, then stem cells become unrestricted and expand dramatically. This work demonstrates that the colonic epithelium requires coordinated ERK signaling dynamics to maintain patterning and tissue homeostasis. Our work reveals how ERK can antagonize stem cells while supporting cell replacement and the function of the gut.
    Keywords:  cell biology; developmental biology; human
  5. JCI Insight. 2022 Sep 13. pii: e148309. [Epub ahead of print]
      High-fat diet (HFD) contributes to the increased incidence of colorectal cancer; but the mechanisms are unclear. We found that R-spondin 3 (Rspo3), a ligand for LGR4 and LGR5, was the major subtype and produced by myofibroblasts beneath the crypts in the intestine; HFD upregulated colonic Rspo3, LGR4, LGR5 and β-catenin gene expressions in specific pathogen free rodents, but not in germfree mice, and the upregulations were prevented by bile acids (BA) binder, cholestyramine (CHO) or antibiotic treatment, indicating mediating by both BA and gut microbiota. CHO or antibiotic treatments prevented HFD-induced enrichment of Lachnospiraceae and Rumincoccaceae, which are capable of transforming 10 into 20 BA. Oral administration of deoxycholic acid (DCA), or inoculation of a combination of BA deconjugator Lactobacillus plantarum and 7-α-dehydroxylase-containing Clostridium scindens with HFD to germfree mice increased colonic Rspo3 mRNA, indicating that formation of 20 BA by gut microbiota is responsible for HFD-induced upregulation of Rspo3. In primary myofibroblasts DCA increased Rpso3 mRNA via TGR5. Finally, we showed that CHO or conditional deletion of Rspo3 prevented HFD- or DCA- induced intestinal proliferation. We conclude that secondary BA is responsible for HFD-induced upregulation of Rspo3, which in turn mediates HFD-induced intestinal epithelial proliferation.
    Keywords:  Colorectal cancer; Gastroenterology; Mouse stem cells
  6. Front Immunol. 2022 ;13 988071
      T-cell exhaustion plays a pivotal role in the resistance of microsatellite-stable colorectal cancer (CRC) to immunotherapy. Identifying and targeting T-cell exhaustion-activating mechanisms is a promising strategy to augment the effects of immunotherapy. Here, we found that thymidine phosphorylase (TYMP) plays a decisive role in inducing systemic T-cell exhaustion and abrogating the efficacy of dendritic cell (DC) therapy in a CRC model. Targeting TYMP with tipiracil hydrochloride (TPI) induces immunological cell death (ICD). The combined effects of TPI and imiquimod-activated DCs turn CT26 tumors into immunologically 'hot' tumors by inducing ICD in vivo. High-dimensional cytometry analysis revealed T-cell and IFN-γ dependency on the therapeutic outcome. In addition, chemoimmunotherapy converts intratumoral Treg cells into Th1 effector cells and eliminates tumor-associated macrophages, resulting in higher cytotoxic T lymphocyte infiltration and activation. This effect is also associated with the downregulation of PD-L1 expression in tumors, leading to the prevention of T-cell exhaustion. Thus, cooperative and cognitive interactions between dendritic cells and immunogenic cell death induced by therapy with TPI promote the immune response and tumoricidal activities against microsatellite stable colorectal cancer. Our results support TYMP targeting to improve the effects of DC immunotherapy and outcomes in CRC.
    Keywords:  T-cell exhaustion; colorectal cancer; dendritic cell (DC) vaccine; immunogenic cell death (ICD); thymidine phosphorylase (TP); tumor immune microenvironment (TIM)
  7. Nat Med. 2022 Sep 12.
      Anti-BRAF/EGFR therapy was recently approved for the treatment of metastatic BRAFV600E colorectal cancer (mCRCBRAF-V600E). However, a large fraction of patients do not respond, underscoring the need to identify molecular determinants of treatment response. Using whole-exome sequencing in a discovery cohort of patients with mCRCBRAF-V600E treated with anti-BRAF/EGFR therapy, we found that inactivating mutations in RNF43, a negative regulator of WNT, predict improved response rates and survival outcomes in patients with microsatellite-stable (MSS) tumors. Analysis of an independent validation cohort confirmed the relevance of RNF43 mutations to predicting clinical benefit (72.7% versus 30.8%; P = 0.03), as well as longer progression-free survival (hazard ratio (HR), 0.30; 95% confidence interval (CI), 0.12-0.75; P = 0.01) and overall survival (HR, 0.26; 95% CI, 0.10-0.71; P = 0.008), in patients with MSS-RNF43mutated versus MSS-RNF43wild-type tumors. Microsatellite-instable tumors invariably carried a wild-type-like RNF43 genotype encoding p.G659fs and presented an intermediate response profile. We found no association of RNF43 mutations with patient outcomes in a control cohort of patients with MSS-mCRCBRAF-V600E tumors not exposed to anti-BRAF targeted therapies. Overall, our findings suggest a cross-talk between the MAPK and WNT pathways that may modulate the antitumor activity of anti-BRAF/EGFR therapy and uncover predictive biomarkers to optimize the clinical management of these patients.
  8. Front Immunol. 2022 ;13 927213
      Recently, Toll-like receptors (TLRs) have been extensively studied in radiation damage, but the inherent defects of high toxicity and low efficacy of most TLR ligands limit their further clinical transformation. CRX-527, as a TLR4 ligand, has rarely been reported to protect against radiation. We demonstrated that CRX-527 was safer than LPS at the same dose in vivo and had almost no toxic effect in vitro. Administration of CRX-527 improved the survival rate of total body irradiation (TBI) to 100% in wild-type mice but not in TLR4-/- mice. After TBI, hematopoietic system damage was significantly alleviated, and the recovery period was accelerated in CRX-527-treated mice. Moreover, CRX-527 induced differentiation of HSCs and the stimulation of CRX-527 significantly increased the proportion and number of LSK cells and promoted their differentiation into macrophages, activating immune defense. Furthermore, we proposed an immune defense role for hematopoietic differentiation in the protection against intestinal radiation damage, and confirmed that macrophages invaded the intestines through peripheral blood to protect them from radiation damage. Meanwhile, CRX-527 maintained intestinal function and homeostasis, promoted the regeneration of intestinal stem cells, and protected intestinal injury from lethal dose irradiation. Furthermore, After the use of mice, we found that CRX-527 had no significant protective effect on the hematopoietic and intestinal systems of irradiated TLR4-/- mice. in conclusion, CRX-527 induced differentiation of HSCs protecting the intestinal epithelium from radiation damage.
    Keywords:  TLR4 activation; hematopoiesis; intestinal stem cells; irradiation damage; macrophage activation
  9. Adv Exp Med Biol. 2022 ;1390 155-167
      Vitamin D is a conditionally required nutrient that can either be obtained from skin synthesis following UVB exposure from the diet. Once in the body, it is metabolized to produce the endocrine hormone, 1,25 dihydroxyvitamin D (1,25(OH)2D), that regulates gene expression in target tissues by interacting with a ligand-activated transcription factor, the vitamin D receptor (VDR). The first, and most responsive, vitamin D target tissue is the intestine. The classical intestinal role for vitamin D is the control of calcium metabolism through the regulation of intestinal calcium absorption. However, studies clearly show that other functions of the intestine are regulated by the molecular actions of 1,25(OH)2 D that are mediated through the VDR. This includes enhancing gut barrier function, regulation of intestinal stem cells, suppression of colon carcinogenesis, and inhibiting intestinal inflammation. While research demonstrates that there are both classical, calcium-regulating and non-calcium regulating roles for vitamin D in the intestine, the challenge facing biomedical researchers is how to translate these findings in ways that optimize human intestinal health.
    Keywords:  Absorption; Calcium; Cancer; Inflammation; Stem cell; Tight junction; VDR; Vitamin D
  10. Nat Rev Gastroenterol Hepatol. 2022 Sep 12.
      The intestinal tract faces numerous challenges that require several layers of defence. The tight epithelium forms a physical barrier that is further protected by a mucus layer, which provides various site-specific protective functions. Mucus is produced by goblet cells, and as a result of single-cell RNA sequencing identifying novel goblet cell subpopulations, our understanding of their various contributions to intestinal homeostasis has improved. Goblet cells not only produce mucus but also are intimately linked to the immune system. Mucus and goblet cell development is tightly regulated during early life and synchronized with microbial colonization. Dysregulation of the developing mucus systems and goblet cells has been associated with infectious and inflammatory conditions and predisposition to chronic disease later in life. Dysfunctional mucus and altered goblet cell profiles are associated with inflammatory conditions in which some mucus system impairments precede inflammation, indicating a role in pathogenesis. In this Review, we present an overview of the current understanding of the role of goblet cells and the mucus layer in maintaining intestinal health during steady-state and how alterations to these systems contribute to inflammatory and infectious disease.
  11. iScience. 2022 Sep 16. 25(9): 105004
      Glucose, the critical energy source in the human body, is considered a potential risk factor in various autoimmune diseases when consumed in high amounts. However, the roles of glucose at moderate doses in the regulation of autoimmune inflammatory diseases and CD4+ T cell responses are controversial. Here, we show that while glucose at a high concentration (20% w/v) promotes intestinal inflammation, it suppresses colitis at a moderate dose (6% w/v), which increases the proportion of intestinal regulatory T (Treg) cells but does not affect effector CD4+ T cells. Glucose treatment promotes Treg cell differentiation but it does not affect Treg stability. Feeding glucose alters gut microbiota compositions, which are not involved in the glucose induction of Treg cells. Glucose promotes aryl hydrocarbon receptor (AhR) activation to induce Treg polarization. These findings reveal the different effects of glucose at different doses on the intestinal immune response.
    Keywords:  Biological sciences; Cell biology; Components of the immune system; Immunology
  12. Front Oncol. 2022 ;12 953321
      Background: Tumor-infiltrating immune cells (TIICs) are associated with chemotherapy response. This study aimed to explore the prognostic value of a TIIC-related tumor microenvironment score (TMEscore) in patients with colorectal cancer (CRC) who underwent chemotherapy and construct a TMEscore-related gene signature to determine its predictive value.Methods: Gene profiles of patients who underwent fluoropyrimidine-based chemotherapy were collected, and their TIIC fractions were calculated and clustered. Differentially expressed genes (DEGs) between clusters were used to calculate the TMEscore. The association between the TMEscore, chemotherapy response, and survival rate was analyzed. Machine learning methods were used to identify key TMEscore-related genes, and a gene signature was constructed to verify the predictive value.
    Results: Two clusters based on the TIIC fraction were identified, and the TMEscore was calculated based on the DEGs of the two clusters. The TMEscore was higher in patients who responded to chemotherapy than in those who did not, and was associated with the survival rate of patients who underwent chemotherapy. Three machine learning methods, support vector machine (SVM), decision tree (DT), and Extreme Gradient Boosting (XGBoost), identified three TMEscore-related genes (ADH1C, SLC26A2, and NANS) associated with the response to chemotherapy. A TMEscore-related gene signature was constructed, and three external cohorts validated that the gene signature could predict the response to chemotherapy. Five datasets and clinical samples showed that the expression of the three TMEscore-related genes was increased in tumor tissues compared to those in control tissues.
    Conclusions: The TIIC-based TMEscore was associated with the survival of CRC patients who underwent fluoropyrimidine-based chemotherapy, and predicted the response to chemotherapy. The TMEscore-related gene signature had a better predictive value for response to chemotherapy than for survival.
    Keywords:  TMEscore; chemotherapy; colorectal cancer; gene signature; machine learning; tumor-infiltrating immune cells
  13. Cell Mol Gastroenterol Hepatol. 2022 Sep 08. pii: S2352-345X(22)00194-1. [Epub ahead of print]
      Neutrophils are the most abundant leukocyte population in the human circulatory system and are rapidly recruited to sites of inflammation. Neutrophils play a multifaceted role in intestinal inflammation, as they contribute to the elimination of invading pathogens. Recently, their role in epithelial restitution has been widely recognized; however, they are also associated with bystander tissue damage. The intestinal epithelium provides a physical barrier to prevent direct contact of luminal contents with subepithelial tissues, which is extremely important for the maintenance of intestinal homeostasis. Numerous studies have demonstrated that transepithelial migration of neutrophils is closely related to disease symptoms and disruption of crypt architecture in inflammatory bowel disease (IBD) and experimental colitis. There has been growing interest in how neutrophils interact with the epithelium under inflammatory conditions. Most studies focus on the effects of neutrophils on intestinal epithelial cells (IECs); however, the effects of IECs on neutrophils during intestinal inflammation need to be well established. Based on these data, we have summarized recent articles on the role of neutrophil-epithelial interactions in intestinal inflammation, particularly highlighting the epithelium-derived molecular regulators that mediate neutrophil recruitment, transepithelial migration, and detachment from the epithelium, as well as the functional consequences of their crosstalk. A better understanding of these molecular events may help develop novel therapeutic targets for mitigating the deleterious effects of neutrophils in IBD.
    Keywords:  Inflammatory bowel disease; intestinal epithelium; neutrophil–epithelial interactions
  14. Biochim Biophys Acta Rev Cancer. 2022 Sep 10. pii: S0304-419X(22)00122-6. [Epub ahead of print] 188797
      Colorectal cancer (CRC) is one of the most common cancers worldwide, which ranks third in terms of incidence and the second leading cause of cancer-related mortality. Metabolic reprogramming within the tumor microenvironment (TME) has been proved intimately involved in the initiation and malignant progression of CRC. Signal messengers, including cytokines, metabolites, and exosomes among others, derived from cancer cells can be utilized by the surrounding cells within the TME to induce metabolic alteration and cancer-associated transformation. In turn, the cargos secreted from cancer-associate cells further provide the nutrition and energy supply for cancer cells, supporting their metabolic reprogramming to promote proliferation, migration, metastasis, and radiochemoresistance. In this review, we focus on the main cellular components in the TME: CAFs, TAMs, lymphocytes and neutrophils, and enumerate and integrate how the metabolic interactions between these components and cancer cells reshape TME to foster CRC malignancy.
    Keywords:  Colorectal cancer; Metabolic reprogramming; Tumor microenvironment
  15. Clinics (Sao Paulo). 2022 ;pii: S1807-5932(22)02958-1. [Epub ahead of print]77 100070
      BACKGROUND: Relapse and metastasis of patients with Colorectal Cancer (CRC) is the major obstacle to the long-term life of patients. Its mechanisms remain defined.METHODS: A total of 48 CRC patients were enrolled and 68 samples were obtained from the peripheral blood of patients before or after treatments in this study. Twenty non-cancer patients were also detected as a negative control. Circulating Tumor Cells (CTCs), including Epithelial CTCs (eCTCs), Mesenchymal (MCTCs), and epithelial/mesenchymal mixed phenotypes (mixed CTCs), were identified by CanPatrolTM CTC enrichment and RNA in situ hybridization. The relationship between CTCs number and Progression-Free Survival (PFS) or Overall Survival (OS) was evaluated.
    RESULTS: Thirty-four of 48 patients (70.8%) were found to have positive CTCs. Total CTCs and MCTCs in the post-treatment had a significant correlation PFS and OS. When total CTCs or MCTCs in 5 mL blood of patients were more than 6 CTCs or 5 MCTCs, PFS of the patients was significantly shorter (p < 0.05) than that in patients with less than 6 CTCs or 5 MCTCs. The patients with > 5 CTCs count changes were found to exhibit poor PFS and OS rates (p < 0.05).
    CONCLUSION: Total CTCs and MCTCs number detection in patients with colorectal cancer was very useful biomarker for predicting the prognosis of patients. Higher CTCs or MCTCs had poorer PFS and OS rates.
    Keywords:  Circulating tumour cells; Colon cancer; Metastasis; Overall survival; Relapse
  16. J Immunother Cancer. 2022 Sep;pii: e004219. [Epub ahead of print]10(9):
      BACKGROUND: Onco-immunogenic molecule CD155 is overexpressed in various tumor microenvironments (TME) including in colorectal cancer (CRC). Tumor-associated macrophages (TAMs) are the most abundant immune cells in CRC TME and play a vital role in CRC progression and metastasis. Most studies have focused on investigating the role of CRC cell-specific CD155 on CRC progression, while the contribution of TAMs-specific CD155 is still unknown. Here, we sought to investigate the expression pattern of CD155 in CRC TAMs and its role in tumor immunity and progression.METHODS: CD155 expression patterns in CRC TAMs and macrophages in paratumor or adjacent normal tissue were analyzed in 50 patients with CRC using flow cytometry and in 141 patients with CRC using immunohistochemistry. The correlation of CD155 expression level in TAMs with M1 and M2 phenotypic transition was analyzed. The role of macrophage-specific CD155 in CRC progression and tumor immune response was investigated in vitro and in vivo. We further analyzed the effect of CRC cells on the regulation of CD155 expression in macrophages.
    RESULTS: CRC TAMs from clinical samples showed robustly higher expression of CD155 than macrophages from paratumor and adjacent normal tissues. The CD155 expression level was higher in TAMs of CRC at III/IV stages compared with the I/II stages and was negatively associated with the survival of patients with CRC. CD155+ TAMs showed an M2 phenotype and higher expression of interleukin (IL)-10 and transforming growth factor (TGF)-β. CD155+ macrophages promoted CRC cell migration, invasion, and tumor growth supporting the findings from the clinical tissue analysis. This effect was mainly regulated by TGF-β-induced STAT3 activation-mediated release of matrix metalloproteinases (MMP)2 and MMP9 in CRC cells. CD155-⁄- bone marrow transplantation in wild-type mice, as well as CD155- macrophages treatment, promoted the antitumor immune response in the mice ectopic CRC model. Additionally, CRC cells released IL-4 to trigger CD155 expression in macrophages indicating the regulatory role of CRC cells in the development of CD155+ TAMs.
    CONCLUSIONS: These findings indicated that CD155+ TAMs are responsible for the M2-phenotype transition, immunosuppression, and tumor progression in CRC. The specific localization of CD155+ TAMs in CRC tissue could turn into a potential therapeutic target for CRC treatment.
    Keywords:  immunity; tumor escape; tumor microenvironment
  17. PLoS One. 2022 ;17(9): e0274390
      Spleen tyrosine kinase (Syk) expression have been both positively and negatively associated with tumorigenesis. Our goal was to evaluate the contribution of Syk and its two splice variants, full length Syk (L) and short isoform Syk (S), in the tumor biology of colorectal cancer cells (CRC). The analysis of Syk expression in primary human colorectal tumors, as well as the analysis of TCGA database, revealed a high Syk mRNA expression score in colorectal cancer tumors, suggesting a tumor promotor role of Syk in CRC. Our analysis showed that Syk (L) isoform is highly expressed in the majority of the tumor tissues and that it remains expressed in tumors in which global Syk expression is downregulated, suggesting the dependence of tumors to Syk (L) isoform. We also identified a small cluster of tumor tissues, which express a high proportion of Syk (S) isoform. This specific cluster is associated with overexpressed genes related to translation and mitochondria, and down regulated genes implicated in the progression of mitosis. For our functional studies, we used short hairpin RNA tools to target the expression of Syk in CRC cells bearing the activating K-Ras (G13D) mutation. Our results showed that while global Syk knock down increases cell proliferation and cell motility, Syk (L) expression silencing affects the viability and induces the apoptosis of the cells, confirming the dependence of cells on Syk (L) isoform for their survival. Finally, we report the promising potential of compound C-13, an original non-enzymatic inhibitor of Syk isolated in our group. In vitro studies showed that C-13 exerts cytotoxic effects on Syk-positive CRC cells by inhibiting their proliferation and their motility, and by inducing their apoptosis, while Syk-negative cell lines viability was not affected. Moreover, the oral and intraperitoneal administration of C-13 reduced the tumor growth of CRC DLD-1 cells xenografts in Nude mice in vivo.
  18. Hum Cell. 2022 Sep 14.
      Although PYCR1 is a well-recognized oncogenic gene for malignant tumors, the causal relationship of its expression with malignant growth and cytotoxic chemotherapeutics remains unclear. Therefore, this study aimed to clarify the role of PYCR1 and its interaction with SLC25A10 in a chemotherapeutic agent 5-fluorouracil (5-FU)'s toxicity to colorectal cancer cells. PYCR1 and SLC25A10 expressions were detected in The Cancer Genome Atlas database and colon adenocarcinoma (COAD) clinical samples. PYCR1 upregulation was associated with SLC25A10 expression and poor prognosis, and its high expression indicated decreased survival rates in patients with COAD. PYCR1 overexpression inhibited lipid reactive oxygen species production and promoted SLC25A10 expression in colorectal cancer cells. PYCR1 silencing enhanced the antitumor effects of 5-FU. Ferroptosis inhibitor deferoxamine suppressed the antitumor effects of PYCR1 silencing, whereas ferroptosis inducer erastin inhibited the protumor effects of PYCR1 overexpression. SLC25A10 overexpression reversed the antitumor effects of PYCR1 silencing in vitro and inhibited the antitumor effects of erastin in vivo. Therefore, PYCR1 is an oncogenic gene that promotes colorectal tumor growth and desensitizes colorectal cancer cells to 5-FU cytotoxicity by preventing apoptosis and ferroptosis.
    Keywords:  Apoptosis; Colorectal cancer; Ferroptosis; PYCR1; Proliferation; SLC25A10
  19. Am J Transl Res. 2022 ;14(8): 5455-5465
      BACKGROUND: Previous studies have revealed the overexpression of Notch receptor 1 (NOTCH1) and pyruvate kinase M2 (PKM2) in colorectal cancer (CRC) tissue and their relationship to disease development. However, whether there is synergy between PKM2 and NOTCH1 needs to be verified. This study aims to analyze the mechanism and relationship between NOTCH1 and PKM2 in CRC.METHODS: Immunohistochemistry was used to measure the expression of NOTCH1 and PKM2 in colorectal cancer, and the correlation between them was analyzed by Pearson test. The protein and mRNA expressions in CRC cell lines were determined by western blot (WB) and real-time quantitative reverse transcription PCR (qRT-PCR). Compound 3K and tangeretin (TGN) were used to inhibit the expressions of PKM2 and NOTCH1, respectively. The wound healing assay and CCK-8 assay were applied to measure the migration and proliferation of cancer cells.
    RESULTS: Immunohistochemical analysis showed that NOTCH1 and PKM2 were overexpressed in patients with colorectal cancer, and patients with overexpression showed a higher number of lymph node metastases and high tumor stage (III+IV) (P<0.05). In addition, Pearson test showed that the level of NOTCH1 was positively correlated with the level of PKM2 (P<0.05). WB and qRT-PCR showed that the protein and mRNA levels of NOTCH1 and PKM2 in colorectal cancer cells were significantly up-regulated (P<0.05). The inhibition of PKM2 and NOTCH1 had a synergistic effect on reducing the invasion and proliferation of CRC cells.
    CONCLUSION: NOTCH1 and PKM2 are highly expressed in CRC patients. Inhibiting the expression of NOTCH1 and PKM2 can inhibit the growth and metastasis of CRC cells, providing therapeutic targets for the treatment of CRC.
    Keywords:  NOTCH1; colorectal cancer; compound 3k; pyruvate kinase M2; synergistic impact; tangeretin
  20. Front Immunol. 2022 ;13 988246
      Colorectal cancer (CRC) has a high incidence rate and poor prognosis, and the available treatment approaches have limited therapeutic benefits. Therefore, understanding the underlying mechanisms of occurrence and development is particularly crucial. Increasing attention has been paid to the pathophysiological role of cancer-associated fibroblasts (CAFs) in the heterogeneous tumour microenvironment. CAFs play a crucial role in tumorigenesis, tumour progression and treatment response. However, routine tissue sequencing cannot adequately reflect the heterogeneity of tumours. In this study, single-cell sequencing was used to examine the fibroblast population in CRC. After cluster analysis, the fibroblast population was divided into four subgroups. The distribution and role of these four subgroups in CRC were found to be different. Based on differential gene expression and lasso regression analysis of the main marker genes in these subgroups, four representative genes were obtained, namely, TCF7L1, FLNA, GPX3 and MMP11. Patients with CRC were divided into the low- and high-risk groups using the prognostic risk model established based on the expression of these four genes. The prognosis of patients in different risk groups varied significantly; patients with low-risk scores had a greater response to PDL1 inhibitors, significant clinical benefits and significantly prolonged overall survival. These effects may be attributed to inhibition of the function of T cells in the immune microenvironment and promotion of the function of tumour-associated macrophages.
    Keywords:  FLNA; GPX3; MMP11; TCF7L1; cancer-associated fibroblasts; colorectal cancer; prognostic risk model; single-cell sequencing
  21. Cell Discov. 2022 Sep 14. 8(1): 92
      Small bowel adenocarcinomas (SBAs) are rare malignant tumors with a high mortality rate, and their molecular characteristics are still largely unexplored. Here we performed single-cell RNA sequencing for tumor samples from 12 SBA patients and predicted drug candidates for SBA. We identified four prevalent subtypes of malignant cells with distinct signatures including cell cycle program, mitochondria program, metabolism program and epithelial-mesenchymal transition (EMT) program. The progression relationships of these four subtypes of malignant cells were also revealed, which started from the cell cycle program, through the mitochondria program and then progressing into either the metabolism program or the EMT program. Importantly, ligand-receptor interaction pairs were found to be specifically enriched in pairs of EMT-program malignant cells and highly exhausted CD8+ T cells, suggesting that cancer cell subpopulations with EMT features may contribute most to the exhaustion of T cells. We also showed that the duodenal subtype of SBA exhibited molecular features more similar to gastric cancer whereas jejunal subtype of SBA more similar to colorectal cancer. Especially, we predicted specific drugs for SBA based on differential gene expression signatures between malignant cells and normal epithelial cells of SBA, and verified more potent inhibitory effects of volasertib and tozasertib for SBA cancer cells than conventional drugs of SBA at the same concentration, which provides new clues for treatments of SBA. In summary, our study provides a blueprint of the molecular signatures of both tumor cells and tumor microenvironment cells in SBA and reveals potential targets and drug candidates for its clinical treatments.
  22. Biology (Basel). 2022 Jun 30. pii: 997. [Epub ahead of print]11(7):
      We investigated the effects of PPARα activators fenofibrate and WY-14643 as well as the PPARα inhibitor GW6471 on the PI3K/Akt/PTEN pathway of intestinal cell differentiation. Our previous study showed that all these compounds increased the expression of villin, a specific marker of intestinal cell differentiation in HT-29 and Caco2 cells. Our current results confirmed the central role of lipid messenger phosphatidylinositol-4,5-bisphosphate (PIP2), a known player in brush border formation, in mediating the effects of tested PPARα ligands. Although all tested compounds increased its levels, surprisingly, each of them affected different PIP2-metabolizing enzymes, especially the levels of PIP5K1C and PTEN. Moreover, we found a positive relationship between the expression of PPARα itself and PIP2 as well as PIP5K1C. By contrast, PPARα was negatively correlated with PTEN. However, the expression of antigens of interest was independent of PPARα subcellular localization, suggesting that it is not directly involved in their regulation. In colorectal carcinoma tissues we found a decrease in PTEN expression, which was accompanied by a change in its subcellular localization. This change was also observed for the regulatory subunit of PI3K. Taken together, our data revealed that fenofibrate, WY-14643, and GW6471 affected different members of the PI3K/Akt/PTEN pathway. However, these effects were PPARα-independent.
    Keywords:  carcinogenesis; fibrates; intestinal cell differentiation; phosphatidylinositol-4,5-bisphosphate
  23. Trends Cancer. 2022 Sep 08. pii: S2405-8033(22)00189-3. [Epub ahead of print]
      In a study in Science, Reis et al. describe a temporal segregation of γδ T cell activities in colorectal cancer (CRC). Initially tumor surveillance is orchestrated by interferon-γ (IFN-γ)-producing and cytotoxic γδ T cell subsets, but once the tumor thrives, it becomes infiltrated by interleukin (IL)-17+ γδ T cell subsets that promote its growth.