bims-instec 2022-06-26 papers

bims-instec

Biomed News

on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration

Issue of 2022–06–26
fiveteen papers selected by
Maria-Virginia Giolito, IRFAC/UMR-S1113 INSERM

Lymphatics act as a signaling hub to regulate intestinal stem cell activity.
Cell and chromatin transitions in intestinal stem cell regeneration.
Patient-Derived Organoid Serves as a Platform for Personalized Chemotherapy in Advanced Colorectal Cancer Patients.
Glutathione Peroxidase 4 as a Therapeutic Target for Anti-Colorectal Cancer Drug-Tolerant Persister Cells.
Tissue-Specific Downregulation of Fatty Acid Synthase Suppresses Intestinal Adenoma Formation via Coordinated Reprograming of Transcriptome and Metabolism in the Mouse Model of Apc-Driven Colorectal Cancer.
Drug Resistance in Colorectal Cancer: From Mechanism to Clinic.
Identification of a neural development gene expression signature in colon cancer stem cells reveals a role for EGR2 in tumorigenesis.
Multidrug Resistance in Cancer Cells: Focus on a Possible Strategy Plan to Address Colon Carcinoma Cells.
HOXA9 Overexpression Contributes to Stem Cell Overpopulation That Drives Development and Growth of Colorectal Cancer.
Adoptive NK Cell Transfer as a Treatment in Colorectal Cancer Patients: Analyses of Tumour Cell Determinants Correlating With Efficacy In Vitro and In Vivo.
Integrative Analysis Revealed Stemness Features and a Novel Stemness-Related Classification in Colorectal Cancer Patients.
Human 2D Crypt Model for Assaying Intestinal Stem Cell Proliferation and Differentiation.
Cancer stem cell marker expression and methylation status in patients with colorectal cancer.
Molecular mechanisms underlying the resistance of BRAF V600E-mutant metastatic colorectal cancer to EGFR/BRAF inhibitors.
Single-cell analyses define a continuum of cell state and composition changes in the malignant transformation of polyps to colorectal cancer.

Cell Stem Cell. 2022 Jun 15. pii: S1934-5909(22)00207-7. [Epub ahead of print]

Lymphatics act as a signaling hub to regulate intestinal stem cell activity.

Rachel E Niec, Tinyi Chu, Marina Schernthanner, Shiri Gur-Cohen, Lynette Hidalgo, Hilda Amalia Pasolli, Kathleen A Luckett, Zhong Wang, Sohni R Bhalla, Francesco Cambuli, Raghu P Kataru, Karuna Ganesh, Babak J Mehrara, Dana Pe'er, Elaine Fuchs.

  Barrier epithelia depend upon resident stem cells for homeostasis, defense, and repair. Epithelial stem cells of small and large intestines (ISCs) respond to their local microenvironments (niches) to fulfill a continuous demand for tissue turnover. The complexity of these niches and underlying communication pathways are not fully known. Here, we report a lymphatic network at the intestinal crypt base that intimately associates with ISCs. Employing in vivo loss of function and lymphatic:organoid cocultures, we show that crypt lymphatics maintain ISCs and inhibit their precocious differentiation. Pairing single-cell and spatial transcriptomics, we apply BayesPrism to deconvolve expression within spatial features and develop SpaceFold to robustly map the niche at high resolution, exposing lymphatics as a central signaling hub for the crypt in general and ISCs in particular. We identify WNT-signaling factors (WNT2, R-SPONDIN-3) and a hitherto unappreciated extracellular matrix protein, REELIN, as crypt lymphatic signals that directly govern the regenerative potential of ISCs.

Keywords:  REELIN; RSPO3; WNTs; intestinal stem cells; lymphatic:stem cell interactome; lymphatics; organoids; spatial deconvolution; spatial transcriptomics of murine large and small intestine; stem cell niches

DOI:  https://doi.org/10.1016/j.stem.2022.05.007
Genes Dev. 2022 Jun 23.

Cell and chromatin transitions in intestinal stem cell regeneration.

Pratik N P Singh, Shariq Madha, Andrew B Leiter, Ramesh A Shivdasani.

  The progeny of intestinal stem cells (ISCs) dedifferentiate in response to ISC attrition. The precise cell sources, transitional states, and chromatin remodeling behind this activity remain unclear. In the skin, stem cell recovery after injury preserves an epigenetic memory of the damage response; whether similar memories arise and persist in regenerated ISCs is not known. We addressed these questions by examining gene activity and open chromatin at the resolution of single Neurog3-labeled mouse intestinal crypt cells, hence deconstructing forward and reverse differentiation of the intestinal secretory (Sec) lineage. We show that goblet, Paneth, and enteroendocrine cells arise by multilineage priming in common precursors, followed by selective access at thousands of cell-restricted cis-elements. Selective ablation of the ISC compartment elicits speedy reversal of chromatin and transcriptional features in large fractions of precursor and mature crypt Sec cells without obligate cell cycle re-entry. ISC programs decay and reappear along a cellular continuum lacking discernible discrete interim states. In the absence of gross tissue damage, Sec cells simply reverse their forward trajectories, without invoking developmental or other extrinsic programs, and starting chromatin identities are effectively erased. These findings identify strikingly plastic molecular frameworks in assembly and regeneration of a self-renewing tissue.

Keywords:  chromatin dynamics of dedifferentiation; intestinal secretory lineage; stem cell recovery after injury

DOI:  https://doi.org/10.1101/gad.349412.122
Front Oncol. 2022 ;12 883437

Patient-Derived Organoid Serves as a Platform for Personalized Chemotherapy in Advanced Colorectal Cancer Patients.

Khamushavalli Geevimaan, Jing-You Guo, Chia-Ning Shen, Jeng-Kai Jiang, Cathy S J Fann, Ming-Jing Hwang, Jr-Wen Shui, Hsiu-Ting Lin, Mei-Jung Wang, Hsuan-Cheng Shih, Anna Fen-Yau Li, Shih-Ching Chang, Shung-Haur Yang, Jeou-Yuan Chen.

   Background: Addition of oxaliplatin to adjuvant 5-FU has significantly improved the disease-free survival and served as the first line adjuvant chemotherapy in advanced colorectal cancer (CRC) patients. However, a fraction of patients remains refractory to oxaliplatin-based treatment. It is urgent to establish a preclinical platform to predict the responsiveness toward oxaliplatin in CRC patients as well as to improve the efficacy in the resistant patients.
Methods: A living biobank of organoid lines were established from advanced CRC patients. Oxaliplatin sensitivity was assessed in patient-derived tumor organoids (PDOs) in vitro and in PDO-xenografted tumors in mice. Based on in vitro oxaliplatin IC50 values, PDOs were classified into either oxaliplatin-resistant (OR) or oxaliplatin-sensitive (OS) PDOs. The outcomes of patients undergone oxaliplatin-based treatment was followed. RNA-sequencing and bioinformatics tools were performed for molecular profiling of OR and OS PDOs. Oxaliplatin response signatures were submitted to Connectivity Map algorithm to identify perturbagens that may antagonize oxaliplatin resistance.
Results: Oxaliplatin sensitivity in PDOs was shown to correlate to oxaliplatin-mediated inhibition on PDO xenograft tumors in mice, and parallelled clinical outcomes of CRC patients who received FOLFOX treatment. Molecular profiling of transcriptomes revealed oxaliplatin-resistant and -sensitive PDOs as two separate entities, each being characterized with distinct hallmarks and gene sets. Using Leave-One-Out Cross Validation algorithm and Logistic Regression model, 18 gene signatures were identified as predictive biomarkers for oxaliplatin response. Candidate drugs identified by oxaliplatin response signature-based strategies, including inhibitors targeting c-ABL and Notch pathway, DNA/RNA synthesis inhibitors, and HDAC inhibitors, were demonstrated to potently and effectively increase oxaliplatin sensitivity in the resistant PDOs.
Conclusions: PDOs are useful in informing decision-making on oxaliplatin-based chemotherapy and in designing personalized chemotherapy in CRC patients.

Keywords:  colorectal cancer; connectivity map; oxaliplatin sensitivity assessment; patient-derived organoids (PDOs); personalized chemotherapy

DOI:  https://doi.org/10.3389/fonc.2022.883437
Front Oncol. 2022 ;12 913669

Glutathione Peroxidase 4 as a Therapeutic Target for Anti-Colorectal Cancer Drug-Tolerant Persister Cells.

Xiaoli Zhang, Yiming Ma, Jianhui Ma, Lan Yang, Qingzhi Song, Hongying Wang, Guoqing Lv.

   Background: Despite the effectiveness of chemotherapy and targeted therapy for colorectal cancer, drug resistance drives therapy failure and tumor relapse. Increasing evidence has suggested that cancer cells can enter a reversible drug-tolerant persister state to survive chemotherapy or targeted agents. However, the traits and treatable vulnerabilities of anti-colorectal cancer drug-tolerant persister cells is not yet known.
Methods: In this study, we established 5-fluorouracil and AZ628-tolerant persister cell models in two colorectal cancer cell lines, namely HCT116 and SW620, and revealed the characteristics of colorectal cancer persister cells by cell viability assay and flow cytometry. We investigated the efficacy and mechanism of ferroptosis inducers RSL3 and FIN56 on persister cells, which are glutathione peroxidase 4 inhibitors. In the xenograft mouse model, we further evaluated the inhibitory effect of RSL3 on tumor regrowth.
Results: Colorectal cancer persister cells, which were enriched in the residual cancer cell population, exhibited reduced drug sensitivity, were largely quiescent and expressed high levels of stem cell-related genes and mesenchymal markers but not epithelial markers. The persister cells were more sensitive and underwent ferroptosis induced by glutathione peroxidase 4 inhibitors. Mechanistically, glutathione peroxidase 4 and ferrous iron, which are pivotal ferroptosis regulators, were upregulated in residual cells or tumors, and were hence potential therapeutic targets of persister cells. In the xenograft model, we confirmed that inhibition of glutathione peroxidase 4 restrained tumor regrowth after discontinuation of anti-cancer drug treatment. Moreover, biopsies obtained from patients with colorectal cancer undergoing neoadjuvant chemoradiotherapy revealed upregulated glutathione peroxidase 4 and ferritin heavy chain 1. High glutathione peroxidase 4 expression correlates with a worse prognosis in colorectal cancer patients.
Conclusions: Our work reveals that the upregulated glutathione peroxidase 4 and ferrous iron in anti-colorectal cancer drug-tolerant persister cells were potential therapeutic targets. Glutathione peroxidase 4 inhibition combined with chemotherapy or targeted therapy may be a promising therapy for colorectal cancer.

Keywords:  colorectal cancer; drug tolerance; ferroptosis; ferrous iron; glutathione peroxidase 4 (GPX4)

DOI:  https://doi.org/10.3389/fonc.2022.913669
Int J Mol Sci. 2022 Jun 10. pii: 6510. [Epub ahead of print]23(12):

Tissue-Specific Downregulation of Fatty Acid Synthase Suppresses Intestinal Adenoma Formation via Coordinated Reprograming of Transcriptome and Metabolism in the Mouse Model of Apc-Driven Colorectal Cancer.

James Drury, Lyndsay E A Young, Timothy L Scott, Courtney O Kelson, Daheng He, Jinpeng Liu, Yuanyan Wu, Chi Wang, Heidi L Weiss, Teresa Fan, Matthew S Gentry, Ramon Sun, Yekaterina Y Zaytseva.

  Altered lipid metabolism is a potential target for therapeutic intervention in cancer. Overexpression of Fatty Acid Synthase (FASN) correlates with poor prognosis in colorectal cancer (CRC). While multiple studies show that upregulation of lipogenesis is critically important for CRC progression, the contribution of FASN to CRC initiation is poorly understood. We utilize a C57BL/6-Apc/Villin-Cre mouse model with knockout of FASN in intestinal epithelial cells to show that the heterozygous deletion of FASN increases mouse survival and decreases the number of intestinal adenomas. Using RNA-Seq and gene set enrichment analysis, we demonstrate that a decrease in FASN expression is associated with inhibition of pathways involved in cellular proliferation, energy production, and CRC progression. Metabolic and reverse phase protein array analyses demonstrate consistent changes in alteration of metabolic pathways involved in both anabolism and energy production. Downregulation of FASN expression reduces the levels of metabolites within glycolysis and tricarboxylic acid cycle with the most significant reduction in the level of citrate, a master metabolite, which enhances ATP production and fuels anabolic pathways. In summary, we demonstrate the critical importance of FASN during CRC initiation. These findings suggest that targeting FASN is a potential therapeutic approach for early stages of CRC or as a preventive strategy for this disease.

Keywords:  Apc mutation; colorectal cancer; colorectal cancer initiation; fatty acid synthase; lipid metabolism

DOI:  https://doi.org/10.3390/ijms23126510
Cancers (Basel). 2022 Jun 14. pii: 2928. [Epub ahead of print]14(12):

Drug Resistance in Colorectal Cancer: From Mechanism to Clinic.

Qianyu Wang, Xiaofei Shen, Gang Chen, Junfeng Du.

  Colorectal cancer (CRC) is one of the leading causes of death worldwide. The 5-year survival rate is 90% for patients with early CRC, 70% for patients with locally advanced CRC, and 15% for patients with metastatic CRC (mCRC). In fact, most CRC patients are at an advanced stage at the time of diagnosis. Although chemotherapy, molecularly targeted therapy and immunotherapy have significantly improved patient survival, some patients are initially insensitive to these drugs or initially sensitive but quickly become insensitive, and the emergence of such primary and secondary drug resistance is a significant clinical challenge. The most direct cause of resistance is the aberrant anti-tumor drug metabolism, transportation or target. With more in-depth research, it is found that cell death pathways, carcinogenic signals, compensation feedback loop signal pathways and tumor immune microenvironment also play essential roles in the drug resistance mechanism. Here, we assess the current major mechanisms of CRC resistance and describe potential therapeutic interventions.

Keywords:  chemotherapeutic agents; colorectal cancer; drug resistance; immunotherapy; molecularly targeted therapy; reversal strategies

DOI:  https://doi.org/10.3390/cancers14122928
iScience. 2022 Jul 15. 25(7): 104498

Identification of a neural development gene expression signature in colon cancer stem cells reveals a role for EGR2 in tumorigenesis.

Joseph L Regan, Dirk Schumacher, Stephanie Staudte, Andreas Steffen, Ralf Lesche, Joern Toedling, Thibaud Jourdan, Johannes Haybaeck, Nicole Golob-Schwarzl, Dominik Mumberg, David Henderson, Balázs Győrffy, Christian R A Regenbrecht, Ulrich Keilholz, Reinhold Schäfer, Martin Lange.

  Recent evidence demonstrates that colon cancer stem cells (CSCs) can generate neurons that synapse with tumor innervating fibers required for tumorigenesis and disease progression. Greater understanding of the mechanisms that regulate CSC driven tumor neurogenesis may therefore lead to more effective treatments. RNA-sequencing analyses of ALDHPositive CSCs from colon cancer patient-derived organoids (PDOs) and xenografts (PDXs) showed CSCs to be enriched for neural development genes. Functional analyses of genes differentially expressed in CSCs from PDO and PDX models demonstrated the neural crest stem cell (NCSC) regulator EGR2 to be required for tumor growth and to control expression of homebox superfamily embryonic master transcriptional regulator HOX genes and the neural stem cell and master cell fate regulator SOX2. These data support CSCs as the source of tumor neurogenesis and suggest that targeting EGR2 may provide a therapeutic differentiation strategy to eliminate CSCs and block nervous system driven disease progression.

Keywords:  Cancer; Stem cells research; Transcriptomics

DOI:  https://doi.org/10.1016/j.isci.2022.104498
Life (Basel). 2022 May 30. pii: 811. [Epub ahead of print]12(6):

Multidrug Resistance in Cancer Cells: Focus on a Possible Strategy Plan to Address Colon Carcinoma Cells.

Chenmala Karthika, Raman Sureshkumar, Mehrukh Zehravi, Rokeya Akter, Faraat Ali, Sarker Ramproshad, Banani Mondal, Milton Kumar Kundu, Abhijit Dey, Md Habibur Rahman, Angela Antonescu, Simona Cavalu.

  Even though various treatment methods are available for cancer, the death curve is not reducing. The diagnosis of cancer at the fourth stage and drug resistance are the leading reasons for treatment failure and lower survival rates. In this review article, we summarize the possible pitfalls during cancer treatment in general, which mainly include multidrug resistance, and propose a hypothesis for colorectal cancer specifically. We also evaluate multidrug resistance in cancer in general and colorectal cancer in particular and hypothesize a concept based on combination therapy with 5-fluorouracil, curcumin, and lipids for the possible management of colorectal cancer. In addition, a hypothetical approach, combining a synthetic agent and a natural chemotherapeutic agent, to treating colorectal cancer is also discussed. This hypothesis could improve the management of colorectal cancer.

Keywords:  5-fluorouracil; P-glycoprotein; cancer; colon cancer; curcumin; lipids; multidrug resistance

DOI:  https://doi.org/10.3390/life12060811
Int J Mol Sci. 2022 Jun 18. pii: 6799. [Epub ahead of print]23(12):

HOXA9 Overexpression Contributes to Stem Cell Overpopulation That Drives Development and Growth of Colorectal Cancer.

Brian Osmond, Caroline O B Facey, Chi Zhang, Bruce M Boman.

  HOX proteins are transcription factors that regulate stem cell (SC) function, but their role in the SC origin of cancer is under-studied. Aberrant expression of HOX genes occurs in many cancer types. Our goal is to ascertain how retinoic acid (RA) signaling and the regulation of HOXA9 expression might play a role in the SC origin of human colorectal cancer (CRC). Previously, we reported that aldehyde dehydrogenase (ALDH) and other RA pathway components are co-expressed in colonic cancer SCs (CSCs) and that overpopulation of ALDH-positive CSCs occurs during colon tumorigenesis. Our hypothesis is RA signaling regulates HOXA9 expression, and dysregulated RA signaling results in HOXA9 overexpression, which contributes to CSC overpopulation in CRC. Immunostaining showed that HOXA9 was selectively expressed in ALDH-positive SCs, and HOXA9 expression was increased in CRCs compared to normal epithelium. Modulating RA signaling in CRC cells (HT29 and SW480) with ATRA and DEAB decreased cell proliferation and reduced HOXA9 expression. Bioinformatics analyses identified a network of proteins that functionally interact with HOXA9, and the genes that encode these proteins, as well as HOXA9, contain RA receptor binding sites. These findings indicate that the expression of HOXA9 and its functional network is regulated by RA signaling in normal colonic SCs, and, when dysregulated, HOXA9 may contribute to CSC overpopulation that drives CRC development and growth. Our study provides a regulatory mechanism that might be useful in developing treatments against CSC overpopulation in CRC.

Keywords:  HOX genes; cancer stem cells; colon cancer; retinoic acid signaling

DOI:  https://doi.org/10.3390/ijms23126799
Front Immunol. 2022 ;13 890836

Adoptive NK Cell Transfer as a Treatment in Colorectal Cancer Patients: Analyses of Tumour Cell Determinants Correlating With Efficacy In Vitro and In Vivo.

Pilar M Lanuza, M Henar Alonso, Sandra Hidalgo, Iratxe Uranga-Murillo, Sandra García-Mulero, Raquel Arnau, Cristina Santos, Xavier Sanjuan, Llipsy Santiago, Laura Comas, Sergio Redrado, Roberto Pazo-Cid, M Jose Agustin-Ferrández, Paula Jaime-Sánchez, Cecilia Pesini, Eva M Gálvez, Ariel Ramírez-Labrada, Maykel Arias, Rebeca Sanz-Pamplona, Julián Pardo.

   Background: Colorectal cancer (CRC) is a heterogeneous disease with variable mutational profile and tumour microenvironment composition that influence tumour progression and response to treatment. While chemoresistant and poorly immunogenic CRC remains a challenge, the development of new strategies guided by biomarkers could help stratify and treat patients. Allogeneic NK cell transfer emerges as an alternative against chemoresistant and poorly immunogenic CRC.
Methods: NK cell-related immunological markers were analysed by transcriptomics and immunohistochemistry in human CRC samples and correlated with tumour progression and overall survival. The anti-tumour ability of expanded allogeneic NK cells using a protocol combining cytokines and feeder cells was analysed in vitro and in vivo and correlated with CRC mutational status and the expression of ligands for immune checkpoint (IC) receptors regulating NK cell activity.
Results: HLA-I downmodulation and NK cell infiltration correlated with better overall survival in patients with a low-stage (II) microsatellite instability-high (MSI-H) CRC, suggesting a role of HLA-I as a prognosis biomarker and a potential benefit of NK cell immunotherapy. Activated allogeneic NK cells were able to eliminate CRC cultures without PD-1 and TIM-3 restriction but were affected by HLA-I expression. In vivo experiments confirmed the efficacy of the therapy against both HLA+ and HLA- CRC cell lines. Concomitant administration of pembrolizumab failed to improve tumour control.
Conclusions: Our results reveal an immunological profile of CRC tumours in which immunogenicity (MSI-H) and immune evasion mechanisms (HLA downmodulation) favour NK cell immunosurveillance at early disease stages. Accordingly, we have shown that allogeneic NK cell therapy can target tumours expressing mutations conferring poor prognosis regardless of the expression of T cell-related inhibitory IC ligands. Overall, this study provides a rationale for a new potential basis for CRC stratification and NK cell-based therapy.

Keywords:  HLA-I; NK cell immunotherapy; cancer biomarker; colorectal cancer; immune checkpoints; tumour immune microenvironment

DOI:  https://doi.org/10.3389/fimmu.2022.890836
Front Cell Dev Biol. 2022 ;10 817509

Integrative Analysis Revealed Stemness Features and a Novel Stemness-Related Classification in Colorectal Cancer Patients.

Meng-Ling Ye, Si-Qi Li, Yi-Xin Yin, Ke-Zhi Li, Ji-Lin Li, Bang-Li Hu.

  Cancer stem cells play crucial roles in colorectal cancer (CRC) tumorigenesis and treatment response. This study aimed to determine the value of the mRNA stemness index (mRNAsi) in CRC and introduce a stemness-related classification to predict the outcome of patients. mRNAsi scores and RNA sequence data of CRC patients were analyzed. We found that high mRNAsi scores were related to early-stage CRC and a better patient prognosis. Two stemness-based subtypes (subtype I and II) were identified. Patients in subtype I presented a significantly better prognosis than those in subtype II. Patients in these two subtype groups presented significantly different tumor immunity scores and immune cell infiltration patterns. Genomic variations revealed that patients in subtype I had a lower tumor mutation burden than those in subtype II. A three-gene stemness subtype predictor was established, showing good diagnostic value in discriminating patients in different subtypes. A prognostic signature based on five stemness-related genes was established and validated in two independent cohorts and clinical samples, showing a better predictive performance than other clinical parameters. We concluded that mRNAsi scores were associated with the clinical outcome in CRC patients. The stemness-related classification was a promising prognostic predictor for CRC patients.

Keywords:  cancer stemness; colorectal cancer; immunotherapy; prognosis; tumor microenvironment

DOI:  https://doi.org/10.3389/fcell.2022.817509
Anal Chem. 2022 Jun 23.

Human 2D Crypt Model for Assaying Intestinal Stem Cell Proliferation and Differentiation.

Yuli Wang, Christopher E Sims, Nancy L Allbritton.

Intestine is a common site of adverse drug effects in clinical trials; thus, improved in vitro models for preclinical screening of pharmaceutical compounds are sought. A planar, self-renewing human intestinal monolayer platform based on primary adult gastrointestinal stem cells, termed the 2D crypt model, has been developed to screen for the effects of various compounds on the intestinal epithelium. The 2D crypt platform is based on a standard 12-well plate format and consists of cell culture inserts with a collagen film overlaying an impermeable film patterned with an array of micron-scale holes. This two-chamber format enables a gradient of growth factors to be applied such that the tissue self-organizes into spatially segregated stem and differentiated cell compartments. The patterned monolayer mimics a gut epithelium in possessing a stem cell niche, migrating proliferative and differentiated cells. Once established, the 2D crypts replicate many aspects of in vivo physiology, including cell migration, maturation, and apoptotic cell death. The planar geometry of the system simplifies dosing, sampling, and imaging during assay. An immunofluorescence-based assay was established to quantitatively assess cell density, proliferation, migration, viability, and the abundance and localization of postmitotic lineages as a function of time. The model was used to perform a small-scale screen of compounds, including signaling molecules, endogenous hormones/cytokines, and microbial metabolites, on tissue homeostasis. Hit compounds that significantly impacted proliferation and/or differentiation were readily identified. The 2D crypt platform represents a significant innovation in the development of microphysiological systems for emulating the gut epithelium for compound screens.

DOI: https://doi.org/10.1021/acs.analchem.2c00905
Oncol Lett. 2022 Jul;24(1): 231

Cancer stem cell marker expression and methylation status in patients with colorectal cancer.

Sandra Mersakova, Katarina Janikova, Michal Kalman, Juraj Marcinek, Marian Grendar, Martin Vojtko, Roman Kycina, Miroslav Pindura, Jan Janik, Peter Mikolajcik, Eva Gabonova, Ludovit Laca, Ester Mejstrikova, Erika Halasova, Jan Strnadel, Zora Lasabova.

  The number of individuals diagnosed with colorectal cancer (CRC) has been on an alarming upward trajectory over the past decade. In some countries, this cancer represents one of the most frequently diagnosed types of neoplasia. Therefore, it is an important demand to study the pathology underlying this disease to gain insights into the mechanism of resistance to treatment. Resistance of tumors to chemotherapy and tumor aggressiveness have been associated with a minor population of neoplastic cells, which are considered to be responsible for tumor recurrence. These types of neoplastic cells are known as cancer stem cells, which have been previously reported to serve an important role in pathogenesis of this malignant disease. Slovakia has one of the highest incidence rates of CRC worldwide. In the present study, the aim was to classify the abundance of selected stem cell markers (CD133, CD166 and Lgr5) in CRC tumors using flow cytometry. In addition, the methylation status of selected genomic regions of CRC biomarkers (ADAMTS16, MGMT, PROM1 (CD133), LGR5 and ALCAM) was investigated by pyrosequencing in a cohort of patients from Martin University Hospital, Martin, Slovakia. Samples from both primary tumors and metastatic tumors were tested. Analysis of DNA methylation in the genomic regions of indicated five CRC biomarkers was also performed, which revealed the highest levels of methylation in the A disintegrin and metalloproteinase with thrombospondin motifs 16 and O6-methyguanine-DNA methyl transferase genes, whereas the lowest levels of methylation were found in genes expressing prominin-1, leucine-rich repeat-containing G-protein-coupled receptor 5 and activated leukocyte cell adhesion molecule. Furthermore, tumor tissues from metastases showed significantly higher levels of CD133+ cells compared with that in primary tumors. Higher levels of CD133+ cells correlated with TNM stage and the invasiveness of CRC into the lymphatic system. Although relatively small number of samples was processed, CD133 marker was consider to be important marker in pathology of CRC.

Keywords:  CD surface markers; cancer stem cells; colorectal cancer; flow cytometry; pyrosequencing and DNA methylation

DOI:  https://doi.org/10.3892/ol.2022.13352
Ther Adv Med Oncol. 2022 ;14 17588359221105022

Molecular mechanisms underlying the resistance of BRAF V600E-mutant metastatic colorectal cancer to EGFR/BRAF inhibitors.

Ting Xu, Xicheng Wang, Zhenghang Wang, Ting Deng, Changsong Qi, Dan Liu, Yanyan Li, Congcong Ji, Jian Li, Lin Shen.

   Background: Combinatorial inhibition of epidermal growth factor receptor (EGFR) and BRAF shows remarkable clinical benefits in patients with BRAF V600E-mutant metastatic colorectal cancer (mCRC). However, the tumor may inevitably develop resistance to the targeted therapy, thereby limiting the response rate and durability. This study aimed to determine the genetic alterations associated with intrinsic and acquired resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC.
Methods: Targeted sequencing of 520 cancer-related genes was performed in tumor tissues and in plasma samples collected from patients with BRAF V600E-mutant mCRC, who were treated with EGFR/BRAF ± MEK inhibitors, before and after the targeted treatment. Clinical benefit was defined as an objective response or a stable disease lasting longer than the median progression-free survival (PFS).
Results: In all, 25 patients with BRAF V600E-mutant mCRC were included in this study. Those with RNF43 mutations (n = 8) were more likely to achieve clinical benefit from EGFR/BRAF inhibitors than those with wild-type RNF43 (87.5% versus 37.5%, p = 0.034). Genetic alterations in receptor tyrosine kinase genes (n = 6) were associated with worse PFS (p = 0.005). Among the 23 patients whose disease progressed after the EGFR/BRAF-targeted therapy, at least one acquired resistance-related mutation was detected in 12 patients. Acquired mutations were most frequently observed in the mitogen-activated protein kinase pathway-related genes (n = 9), including KRAS (G12D and Q61H/R), NRAS (Q61L/R/K and amplification), BRAF (amplification), and MEK1 (K57T). MET amplification and PIK3R1 Q579fs mutation emerged in three patients and one patient, respectively, after disease progression.
Conclusion: Multiple genetic alterations are associated with clinical benefits and resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC. Our findings provide novel insights into strategies for overcoming resistance to EGFR/BRAF inhibitors in patients with BRAF V600E-mutant mCRC.

Keywords:  BRAF mutation; colorectal cancer; drug resistance; predictive biomarker; targeted therapy

DOI:  https://doi.org/10.1177/17588359221105022
Nat Genet. 2022 Jun 20.

Single-cell analyses define a continuum of cell state and composition changes in the malignant transformation of polyps to colorectal cancer.

Winston R Becker, Stephanie A Nevins, Derek C Chen, Roxanne Chiu, Aaron M Horning, Tuhin K Guha, Rozelle Laquindanum, Meredith Mills, Hassan Chaib, Uri Ladabaum, Teri Longacre, Jeanne Shen, Edward D Esplin, Anshul Kundaje, James M Ford, Christina Curtis, Michael P Snyder, William J Greenleaf.

To chart cell composition and cell state changes that occur during the transformation of healthy colon to precancerous adenomas to colorectal cancer (CRC), we generated single-cell chromatin accessibility profiles and single-cell transcriptomes from 1,000 to 10,000 cells per sample for 48 polyps, 27 normal tissues and 6 CRCs collected from patients with or without germline APC mutations. A large fraction of polyp and CRC cells exhibit a stem-like phenotype, and we define a continuum of epigenetic and transcriptional changes occurring in these stem-like cells as they progress from homeostasis to CRC. Advanced polyps contain increasing numbers of stem-like cells, regulatory T cells and a subtype of pre-cancer-associated fibroblasts. In the cancerous state, we observe T cell exhaustion, RUNX1-regulated cancer-associated fibroblasts and increasing accessibility associated with HNF4A motifs in epithelia. DNA methylation changes in sporadic CRC are strongly anti-correlated with accessibility changes along this continuum, further identifying regulatory markers for molecular staging of polyps.

DOI: https://doi.org/10.1038/s41588-022-01088-x