bims-instec Biomed News
on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration
Issue of 2022‒04‒17
nine papers selected by
Maria-Virginia Giolito

  1. Arch Biochem Biophys. 2022 Apr 11. pii: S0003-9861(22)00101-1. [Epub ahead of print] 109216
      BACKGROUND: FAM98A is a microtubule-associated protein involved in cell proliferation and migration, and is frequently dysregulated in epithelial cancers. But its role in the development of colorectal cancer (CRC) cancer remains unknown.METHODS: Immunohistochemical analysis was performed to examine the expression of FAM98A in CRC samples. We also investigated the effects of abnormal expression on the biological behavior of colorectal cancer cells in vitro and in vivo. Immunoblotting and immunoprecipitation were used to screen FAM98A-related signalling pathways and downstream factors.
    RESULTS: FAM98A was upregulated in CRC tissues and CRC cell lines. Overexpression of FAM98A promoted cell proliferation and recovered 5-FU suppressed CRC cell proliferation both in vitro and in vivo. In addition, the Enhanced expression of FAM98A inhibited ferroptosis in CRC cells by activating the translation of xCT in stress granules (SGs). Furthermore, we identified that metformin could reverse FAM98A-mediated 5-FU resistance in CRC cells.
    CONCLUSIONS: Our results for the first time indicate that FAM98A plays a critical role in promoting CRC progression, which provides a novel target for clinical drug resistance of colorectal cancer. And metformin may sensitize 5-FU in the treatment of colorectal cancer.
    Keywords:  5-FU; Colorectal cancer; FAM98A; Ferroptosis
  2. Front Oncol. 2022 ;12 855674
      The drug 5-fluorouracil (5-Fu) is the critical composition of colorectal cancer (CRC) treatments. Prognostic and predictive molecular biomarkers for CRC patients (CRCpts) treated with 5-Fu-based chemotherapy can provide assistance for tailoring treatment approach. Here, we established a molecular biomarker of 5-Fu resistance derived from colorectal cancer organoids (CRCOs) for predicting the survival of CRCpts. Forty-one CRCO cultures were generated from 50 CRC tumor tissues after surgery (82%). The following experiments revealed a great diversity in drug sensitivity for 10 μM 5-Fu treatment tested by using organoid size change. Fourteen cases (34.1%) were 5-Fu sensitive and the other 27 (65.9%) were resistant. Then, differentially expressed genes (DEGs) associated with 5-Fu resistance were outputted by transcriptome sequencing. In particular, DEGs were generated in two comparison groups: 1) 5-Fu sensitive and resistant untreated CRCOs; 2) CRCOs before 5-Fu treatment and surviving CRCOs after 5-Fu treatment. Some molecules and most of the pathways that have been reported to be involved in 5-Fu resistance were identified in the current research. By using DEGs correlated with 5-Fu resistance and survival of CRCpts, the gene signature and drug-resistant score model (DRSM) containing five molecules were established in The Cancer Genome Atlas (TCGA)-CRC cohort by least absolute shrinkage and selection operator (LASSO) regression analysis and 5-fold cross-validation. Multivariate analysis revealed that drug-resistant score (DRS) was an independent prognostic factor for overall survival (OS) in CRCpts in TCGA-CRC cohort (P < 0.001). Further validation results from four Gene Expression Omnibus (GEO) cohorts elucidated that the DRSM based on five genes related to 5-Fu chemosensitivity and developed from patient-derived organoids can predict survival of CRCpts. Meanwhile, our model could predict the survival of CRCpts in different subgroups. Besides, the difference of molecular pathways, tumor mutational burden (TMB), immune response-related pathways, immune score, stromal score, and immune cell proportion were dissected between DRS-high and DRS-low patients in TCGA-CRC cohort.
    Keywords:  5-fluorouracil; colorectal cancer; drug resistance; molecular biomarker; organoids; predict; survival
  3. Am J Cancer Res. 2022 ;12(3): 1393-1408
      Although oxaliplatin-based chemotherapy is the current standard adjuvant therapy for colorectal cancer (CRC), the molecular mechanisms underlying oxaliplatin resistance remain unclear. Here, we examined the molecular mechanisms underlying SLC22A18-associated oxaliplatin resistance and strategies for overcoming oxaliplatin resistance. We evaluated the association between SLC22A18 and prognosis in 337 patients with CRC and its functional significance and studied the mechanisms through which SLC22A18 affects oxaliplatin resistance development in CRC cells, using CRC cell lines and patient-derived cells (PDCs). SLC22A18 downregulation was positively correlated with worse survival in patients with CRC. Low SLC22A18-expressing cells showed relatively lower sensitivity to oxaliplatin than high SLC22A18-expressing cells. In addition, ERK activation was found to be involved in the mechanisms underlying SLC22A18-related oxaliplatin resistance. To confirm ERK pathway dependence, we used an ERK inhibitor and found that combined treatment with oxaliplatin and the ERK inhibitor overcame oxaliplatin resistance in the low SLC22A18-expressing cells. Ex vivo approaches using PDC confirmed the correlation between SLC22A18 expression and oxaliplatin resistance. Results of the in vivo study showed that SLC22A18 expression regulated oxaliplatin efficacy, and that combined treatment with an ERK inhibitor could be a useful therapeutic strategy when SLC22A18 is downregulated. Together, our findings indicate that SLC22A18 could serve as a biomarker for the prediction of oxaliplatin resistance. In cases of oxaliplatin resistance due to low SLC22A18 expression, resistance can be overcome by combined treatment with an ERK inhibitor.
    Keywords:  ERK; Oxaliplatin-resistance; SLC22A18; colorectal cancer; combined treatment
  4. Cancer Sci. 2022 Apr 11.
      The cetuximab gene expression signature and DNA methylation status of colorectal cancer (CRC) are predictive of the therapeutic effects of anti-epidermal growth factor receptor (EGFR) antibody therapy. Since DNA methylation is a means of regulating gene expression, it may play an important role in the expression of cetuximab signature genes. This study aims to determine the effects of aberrant DNA methylation on the regulation of cetuximab signature gene expression. Comprehensive DNA methylation and gene expression data were retrieved from CRC patients in three tumor tissue (TT) cohorts and three normal colorectal mucosa/tumor tissue paired (NCM-TT) cohorts. Of the 231 cetuximab signature genes, 57 exhibited an inverse correlation between the methylation of promoter CpG sites and gene expression level in multiple cohorts. About two-thirds of the promoter CpG sites associated with the 57 genes exhibited this correlation. In all 57 gene promoter regions, the methylation levels in NCMs did not differ according to comparisons based on cetuximab signature or DNA methylation status classification of matched TTs. Thus, the altered expression of 57 genes was caused by aberrant DNA methylation during carcinogenesis. Analysis of the association between cetuximab signature or DNA methylation status and progression-free survival (PFS) of anti-EGFR antibody agents in the same cohort showed that DNA methylation status was most associated with PFS. In conclusion, we found that aberrant DNA methylation regulates specific gene expression in cetuximab signature during carcinogenesis, suggesting that it is one of the important determinants of sensitivity to anti-EGFR antibody agents.
    Keywords:  Colorectal neoplasms; DNA methylation; ErbB Receptors; Genetic Promoter Regions; Transcriptomes
  5. Nat Commun. 2022 Apr 12. 13(1): 1968
      The Pleiotropic Drug Resistance (PDR) network is central to the drug response in fungi, and its overactivation is associated with drug resistance. However, gene regulation of the PDR network is not well understood. Here, we show that the histone chaperone Rtt106 and the chromatin remodeller SWI/SNF control expression of the PDR network genes and confer drug resistance. In Saccharomyces cerevisiae, Rtt106 specifically localises to PDR network gene promoters dependent on transcription factor Pdr3, but not Pdr1, and is essential for Pdr3-mediated basal expression of the PDR network genes, while SWI/SNF is essential for both basal and drug-induced expression. Also in the pathogenic fungus Candida glabrata, Rtt106 and SWI/SNF regulate drug-induced PDR gene expression. Consistently, loss of Rtt106 or SWI/SNF sensitises drug-resistant S. cerevisiae mutants and C. glabrata to antifungal drugs. Since they cooperatively drive PDR network gene expression, Rtt106 and SWI/SNF represent potential therapeutic targets to combat antifungal resistance.
  6. Cancer Discov. 2022 Apr 14. OF1-OF18
      FGFR inhibitors are approved for the treatment of advanced cholangiocarcinoma harboring FGFR2 fusions. However, the response rate is moderate, and resistance emerges rapidly due to acquired secondary FGFR2 mutations or due to other less-defined mechanisms. Here, we conducted high-throughput combination drug screens, biochemical analysis, and therapeutic studies using patient-derived models of FGFR2 fusion-positive cholangiocarcinoma to gain insight into these clinical profiles and uncover improved treatment strategies. We found that feedback activation of EGFR signaling limits FGFR inhibitor efficacy, restricting cell death induction in sensitive models and causing resistance in insensitive models lacking secondary FGFR2 mutations. Inhibition of wild-type EGFR potentiated responses to FGFR inhibitors in both contexts, durably suppressing MEK&sol;ERK and mTOR signaling, increasing apoptosis, and causing marked tumor regressions in vivo. Our findings reveal EGFR-dependent adaptive signaling as an important mechanism limiting FGFR inhibitor efficacy and driving resistance and support clinical testing of FGFR&sol;EGFR inhibitor therapy for FGFR2 fusion-positive cholangiocarcinoma.SIGNIFICANCE: We demonstrate that feedback activation of EGFR signaling limits the effectiveness of FGFR inhibitor therapy and drives adaptive resistance in patient-derived models of FGFR2 fusion-positive cholangiocarcinoma. These studies support the potential of combination treatment with FGFR and EGFR inhibitors as an improved treatment for patients with FGFR2-driven cholangiocarcinoma.
  7. Int J Cancer. 2022 Apr 16.
      Gut microbiota is involved in immune modulation and immune checkpoint inhibitors (ICIs) efficacy. Single arm phase II CAVE-mCRC and CAVE-LUNG clinical trials investigated cetuximab+avelumab combination in RAS wild-type (WT) metastatic colorectal cancer (mCRC) and chemo-refractory non-small cell lung cancer (NSCLC) patients, respectively. A comprehensive gut microbiota genetic analysis was done in basal fecal samples of 14 patients from CAVE-mCRC trial with circulating tumor DNA (ctDNA) RAS/BRAF WT and microsatellite stable (MSS) disease. Results were validated in a cohort of 10 patients from CAVE-Lung trial. 16S rRNA sequencing revealed 23 027 bacteria species in basal fecal samples of 14 patients from CAVE-mCRC trial. In 5 long-term responding patients (PFS, 9-24 months) significant increases in two butyrate-producing bacteria, Agathobacter M104/1 (P = 0.018) and Blautia SR1/5 (P = 0.023) were found compared to 9 patients with shorter PFS (2-6 months). A significantly better progression free survival (PFS) was also observed according to presence or absence of these species in basal fecal samples. For Agathobacter M104/1, median PFS (mPFS) was 13.5 months (95% Confidence Interval, CI, 6.5-20.5 months) vs 4.6 months (95% CI, 1.8-7.4 months); P = 0.006. For Blautia SR1/5, mPFS was 5.9 months (95% CI, 2.2-9.7 months) vs 3.6 months (95% CI, 3.3-4.0 months); P = 0.021. Similarly, in CAVE-Lung validation cohort, Agathobacter M104/1 and Blautia SR1/5 expression was associated with PFS according to their presence or absence in basal fecal samples. Agathobacter and Blautia species could be potential biomarkers of outcome in mCRC, and NSCLC patients treated with cetuximab+avelumab. These findings deserve further investigation. This article is protected by copyright. All rights reserved.
    Keywords:  NSCLC; avelumab; cetuximab; gut microbiota; mCRC
  8. Cell Death Discov. 2022 Apr 14. 8(1): 200
      Small nucleolar RNAs (snoRNAs) are a class of non-coding RNAs that play indispensable roles in cancers, including colorectal cancer (CRC). However, the role of SNORD1C in CRC is unclear. In the current study, SNORD1C expression was measured in CRC tissues using quantitative real-time PCR. A series of in vivo and in vitro experiments were performed to examine the functional role of SNORD1C in CRC. Quantitative real-time PCR, western blotting, sphere formation assay, and chemotherapy resistance analysis were conducted to illustrate the SNORD1C molecular mechanism. SNORD1C was upregulated in CRC and that high SNORD1C expression was related to poor prognosis. After knocking down SNORD1C in CRC cell lines, cell proliferation, colony formation, cell migration, and invasion were alleviated, while apoptosis was increased. Transcriptional RNA-sequencing analysis revealed that following SNORD1C knockdown, β-catenin was downregulated, as was the transcription factor TCF7, which inhibited the Wnt/β-catenin pathway. Meanwhile, levels of the stem cell-related factors were reduced, diminishing cell stemness and tumorigenesis. Our findings suggest that SNORD1C functions via the Wnt/β-catenin pathway to enhance cancer cell stemness in CRC and could be a predictive biomarker for the prognosis ad aggressiveness of this malignancy. Additionally, targeting SNORD1C may be a novel therapeutic strategy for CRC.
  9. J Biol Chem. 2022 Apr 08. pii: S0021-9258(22)00358-1. [Epub ahead of print] 101918
      Protein phosphatase 2A (PP2A) is a serine/threonine dephosphorylating enzyme complex that plays numerous roles in biological processes, including cell growth and metabolism. However, its specific actions in many of these critical pathways are unclear. To explore mechanisms underlying metabolic enzyme regulation in the liver, we investigated the key pathways involved in regulation of xenobiotic metabolizing enzymes in a mouse model with hepatocyte-specific deletion of Ppp2r1a, encoding the Aα subunit of PP2A. We performed transcriptome and phosphoproteome analysis in mouse livers at the age of 3 months and identified 2695 differentially expressed genes (DEGs) and 549 upregulated phosphoproteins in homozygous knockout (HO) mouse livers compared to wild type (WT) littermates. In particular, the expression of metabolic enzymes Cyp2e1, Cyp1a1, Cyp1a2, Mdr1a, and Abcg2 was dramatically altered in HO mouse livers. We also demonstrated that activation of PP2A reversed the decline of metabolic enzyme expression in primary mouse hepatocytes. We found specific PP2A holoenzymes were involved in metabolic enzyme induction through dephosphorylation of transcription factors, nuclear receptors, or the target enzymes themselves, leading to dysregulation of xenobiotic metabolism or drug-induced hepatotoxicity. Notably, we confirmed that a regulatory axis, PP2A B56α-AHR-Cyp1a1 was involved in benzo(a)pyrene-induced cytotoxicity through dephosphorylation of the metabolic nuclear receptor AHR at Ser36. In addition, we showed that PP2A B56δ complexes directly dephosphorylated the multi-drug efflux pump MDR1, contributing to drug resistance against the chemotherapeutic 5-fluorouracil. Taken together, these novel findings demonstrate the involvement of PP2A in the regulation of liver metabolism.
    Keywords:  drug resistance; hepatotoxicity; metabolic enzymes; protein phosphatase 2A; regulatory mode; xenobiotic metabolism