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Nature Microbiology Mar 2020The microbiota has been shown to promote intestinal tumourigenesis, but a possible anti-tumourigenic effect has also been postulated. Here, we demonstrate that changes...
The microbiota has been shown to promote intestinal tumourigenesis, but a possible anti-tumourigenic effect has also been postulated. Here, we demonstrate that changes in the microbiota and mucus composition are concomitant with tumourigenesis. We identified two anti-tumourigenic strains of the microbiota-Faecalibaculum rodentium and its human homologue, Holdemanella biformis-that are strongly under-represented during tumourigenesis. Reconstitution of Apc or azoxymethane- and dextran sulfate sodium-treated mice with an isolate of F. rodentium (F. PB1) or its metabolic products reduced tumour growth. Both F. PB1 and H. biformis produced short-chain fatty acids that contributed to control protein acetylation and tumour cell proliferation by inhibiting calcineurin and NFATc3 activation in mouse and human settings. We have thus identified endogenous anti-tumourigenic bacterial strains with strong diagnostic, therapeutic and translational potential.
Topics: Adult; Aged; Animals; Cell Proliferation; Colonic Neoplasms; DNA, Bacterial; Fatty Acids, Volatile; Female; Firmicutes; Gastrointestinal Microbiome; Humans; In Situ Hybridization, Fluorescence; Intestinal Neoplasms; Intestines; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Middle Aged; RNA, Bacterial
PubMed: 31988379
DOI: 10.1038/s41564-019-0649-5 -
Microbiome May 2021Successful chemoprevention or chemotherapy is achieved through targeted delivery of prophylactic agents during initial phases of carcinogenesis or therapeutic agents to...
BACKGROUND
Successful chemoprevention or chemotherapy is achieved through targeted delivery of prophylactic agents during initial phases of carcinogenesis or therapeutic agents to malignant tumors. Bacteria can be used as anticancer agents, but efforts to utilize attenuated pathogenic bacteria suffer from the risk of toxicity or infection. Lactic acid bacteria are safe to eat and often confer health benefits, making them ideal candidates for live vehicles engineered to deliver anticancer drugs.
RESULTS
In this study, we developed an effective bacterial drug delivery system for colorectal cancer (CRC) therapy using the lactic acid bacterium Pediococcus pentosaceus. It is equipped with dual gene cassettes driven by a strong inducible promoter that encode the therapeutic protein P8 fused to a secretion signal peptide and a complementation system. In an inducible CRC cell-derived xenograft mouse model, our synthetic probiotic significantly reduced tumor volume and inhibited tumor growth relative to the control. Mice with colitis-associated CRC induced by azoxymethane and dextran sodium sulfate exhibited polyp regression and recovered taxonomic diversity when the engineered bacterium was orally administered. Further, the synthetic probiotic modulated gut microbiota and alleviated the chemically induced dysbiosis. Correlation analysis demonstrated that specific bacterial taxa potentially associated with eubiosis or dysbiosis, such as Akkermansia or Turicibacter, have positive or negative relationships with other microbial members.
CONCLUSIONS
Taken together, our work illustrates that an effective and stable synthetic probiotic composed of P. pentosaceus and the P8 therapeutic protein can reduce CRC and contribute to rebiosis, and the validity and feasibility of cell-based designer biopharmaceuticals for both treating CRC and ameliorating impaired microbiota. Video abstract.
Topics: Animals; Azoxymethane; Colitis; Colorectal Neoplasms; Dextran Sulfate; Disease Models, Animal; Gastrointestinal Microbiome; Mice; Mice, Inbred C57BL; Probiotics
PubMed: 34039418
DOI: 10.1186/s40168-021-01071-4 -
Gastroenterology Sep 2020Alterations in the intestinal microbiota affect development of colorectal cancer and drug metabolism. We studied whether the intestinal microbiota affect the ability of...
BACKGROUND & AIMS
Alterations in the intestinal microbiota affect development of colorectal cancer and drug metabolism. We studied whether the intestinal microbiota affect the ability of aspirin to reduce colon tumor development in mice.
METHODS
We performed studies with APC mice and mice given azoxymethane and dextran sulfate sodium to induce colorectal carcinogenesis. Some mice were given antibiotics to deplete intestinal microbes, with or without aspirin, throughout the entire experiment. Germ-free mice were studied in validation experiments. Colon tissues were collected and analyzed by histopathology, quantitative reverse-transcription polymerase chain reaction, and immunoblots. Blood samples and gut luminal contents were analyzed by liquid chromatography/mass spectrometry and an arylesterase activity assay. Fecal samples were analyzed by 16S ribosomal RNA gene and shotgun metagenome sequencing.
RESULTS
Administration of aspirin to mice reduced colorectal tumor number and load in APC mice and mice given azoxymethane and dextran sulfate sodium that had been given antibiotics (depleted gut microbiota), but not in mice with intact microbiota. Germ-free mice given aspirin developed fewer colorectal tumors than conventionalized germ-free mice given aspirin. Plasma levels of aspirin were higher in mice given antibiotics than in mice with intact gut microbiota. Analyses of luminal contents revealed that aerobic gut microbes, including Lysinibacillus sphaericus, degrade aspirin. Germ-free mice fed L sphaericus had lower plasma levels of aspirin than germ-free mice that were not fed this bacterium. There was an inverse correlation between aspirin dose and colorectal tumor development in conventional mice, but this correlation was lost with increased abundance of L sphaericus. Fecal samples from mice fed aspirin were enriched in Bifidobacterium and Lactobacillus genera, which are considered beneficial, and had reductions in Alistipes finegoldii and Bacteroides fragili, which are considered pathogenic.
CONCLUSIONS
Aspirin reduces development of colorectal tumors in APC mice and mice given azoxymethane and dextran sulfate sodium, depending on the presence of intestinal microbes. L sphaericus in the gut degrades aspirin and reduced its chemopreventive effects in mice. Fecal samples from mice fed aspirin were enriched in beneficial bacteria, with reductions in pathogenic bacteria.
Topics: Adenomatous Polyposis Coli Protein; Animals; Anti-Bacterial Agents; Anticarcinogenic Agents; Aspirin; Azoxymethane; Bacillaceae; Bacteroides fragilis; Bacteroidetes; Biological Availability; Carcinogenesis; Colitis; Colon; Colorectal Neoplasms; DNA, Bacterial; Dextran Sulfate; Disease Models, Animal; Dose-Response Relationship, Drug; Feces; Gastrointestinal Microbiome; Germ-Free Life; Humans; Intestinal Mucosa; Male; Mice; Mice, Transgenic; RNA, Ribosomal, 16S
PubMed: 32387495
DOI: 10.1053/j.gastro.2020.05.004 -
Theranostics 2022The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil...
The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil (5FU). Although there is mounting evidence that commensal gut microbiota is essential for effective colon cancer treatment, the detailed molecular mechanisms and the role of gut microbial metabolites remain elusive. The goal of this study is to decipher the impact and mechanisms of gut microbial metabolite, urolithin A (UroA) and its structural analogue, UAS03 on reversal of 5FU-resistant (5FUR) colon cancers. We have utilized the SW480 and HCT-116 parental (5FU-sensitive) and 5FUR colon cancer cells to examine the chemosensitization effects of UroA or UAS03 by using both and models. The effects of mono (UroA/UAS03/5FU) and combinatorial therapy (UroA/UAS03 + 5FU) on cell proliferation, apoptosis, cell migration and invasion, regulation of epithelial mesenchymal transition (EMT) mediators, expression and activities of drug transporters, and their regulatory transcription factors were examined using molecular, cellular, immunological and flowcytometric methods. Further, the anti-tumor effects of mono/combination therapy (UroA or UAS03 or 5FU or UroA/UAS03 + 5FU) were examined using pre-clinical models of 5FUR-tumor xenografts in NRGS mice and azoxymethane (AOM)-dextran sodium sulfate (DSS)-induced colon tumors. Our data showed that UroA or UAS03 in combination with 5FU significantly inhibited cell viability, proliferation, invasiveness as well as induced apoptosis of the 5FUR colon cancer cells compared to mono treatments. Mechanistically, UroA or UAS03 chemosensitized the 5FUR cancer cells by downregulating the expression and activities of drug transporters (MDR1, BCRP, MRP2 and MRP7) leading to a decrease in the efflux of 5FU. Further, our data suggested the UroA or UAS03 chemosensitized 5FUR cancer cells to 5FU treatment through regulating FOXO3-FOXM1 axis. Oral treatment with UroA or UAS03 in combination with low dose i.p. 5FU significantly reduced the growth of 5FUR-tumor xenografts in NRGS mice. Further, combination therapy significantly abrogated colonic tumors in AOM-DSS-induced colon tumors in mice. In summary, gut microbial metabolite UroA and its structural analogue UAS03 chemosensitized the 5FUR colon cancers for effective 5FU chemotherapy. This study provided the novel characteristics of gut microbial metabolites to have significant translational implications in drug-resistant cancer therapeutics.
Topics: ATP Binding Cassette Transporter, Subfamily G, Member 2; Animals; Antimetabolites, Antineoplastic; Azoxymethane; Cell Line, Tumor; Colonic Neoplasms; Coumarins; Drug Resistance, Neoplasm; Fluorouracil; Forkhead Box Protein M1; Forkhead Box Protein O3; Gastrointestinal Microbiome; Humans; Mice; Neoplasm Proteins
PubMed: 35910798
DOI: 10.7150/thno.70754 -
ELife Sep 2021Emerging evidence suggests that the nervous system is involved in tumor development in the periphery, however, the role of the central nervous system remains largely...
Emerging evidence suggests that the nervous system is involved in tumor development in the periphery, however, the role of the central nervous system remains largely unknown. Here, by combining genetic, chemogenetic, pharmacological, and electrophysiological approaches, we show that hypothalamic oxytocin (Oxt)-producing neurons modulate colitis-associated cancer (CAC) progression in mice. Depletion or activation of Oxt neurons could augment or suppress CAC progression. Importantly, brain treatment with celastrol, a pentacyclic triterpenoid, excites Oxt neurons and inhibits CAC progression, and this anti-tumor effect was significantly attenuated in Oxt neuron-lesioned mice. Furthermore, brain treatment with celastrol suppresses sympathetic neuronal activity in the celiac-superior mesenteric ganglion (CG-SMG), and activation of β2 adrenergic receptor abolishes the anti-tumor effect of Oxt neuron activation or centrally administered celastrol. Taken together, these findings demonstrate that hypothalamic Oxt neurons regulate CAC progression by modulating the neuronal activity in the CG-SMG. Stimulation of Oxt neurons using chemicals, for example, celastrol, might be a novel strategy for colorectal cancer treatment.
Topics: Animals; Azoxymethane; Colitis; Colorectal Neoplasms; Dextran Sulfate; Hypothalamus; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Oxytocin; Pentacyclic Triterpenes; Mice
PubMed: 34528509
DOI: 10.7554/eLife.67535 -
Gastroenterology Sep 2019Many genetic and environmental factors, including family history, dietary fat, and inflammation, increase risk for colon cancer development. Peroxisome...
BACKGROUND & AIMS
Many genetic and environmental factors, including family history, dietary fat, and inflammation, increase risk for colon cancer development. Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear receptor that regulates systemic lipid homeostasis. We explored the role of intestinal PPARα in colon carcinogenesis.
METHODS
Colon cancer was induced in mice with intestine-specific disruption of Ppara (Ppara), Ppara (control), and mice with disruption of Ppara that express human PPARA (human PPARA transgenic mice), by administration of azoxymethane with or without dextran sulfate sodium (DSS). Colons were collected from mice and analyzed by immunoblots, quantitative polymerase chain reaction, and histopathology. Liquid chromatography coupled with mass spectrometry-based metabolomic analyses were performed on urine and colons. We used molecular biology and biochemical approaches to study mechanisms in mouse colons, primary intestinal epithelial cells, and colon cancer cell lines. Gene expression data and clinical features of patients with colorectal tumors were obtained from Oncomine, and human colorectal-tumor specimens and adjacent normal tissues were collected and analyzed by immunohistochemistry.
RESULTS
Levels of Ppara messenger RNA were reduced in colon tumors from mice. Ppara mice developed more and larger colon tumors than control mice following administration of azoxymethane, with or without DSS. Metabolomic analyses revealed increases in methylation-related metabolites in urine and colons from Ppara mice, compared with control mice, following administration of azoxymethane, with or without DSS. Levels of DNA methyltransferase 1 (DNMT1) and protein arginine methyltransferase 6 (PRMT6) were increased in colon tumors from Ppara mice, compared with colon tumors from control mice. Depletion of PPARα reduced the expression of retinoblastoma protein, resulting in increased expression of DNMT1 and PRMT6. DNMT1 and PRMT6 decreased expression of the tumor suppressor genes Cdkn1a (P21) and Cdkn1b (p27) via DNA methylation and histone H3R2 dimethylation-mediated repression of transcription, respectively. Fenofibrate protected human PPARA transgenic mice from azoxymethane and DSS-induced colon cancer. Human colon adenocarcinoma specimens had lower levels of PPARA and retinoblastoma protein and higher levels of DNMT1 and PRMT6 than normal colon tissues.
CONCLUSIONS
Loss of PPARα from the intestine promotes colon carcinogenesis by increasing DNMT1-mediated methylation of P21 and PRMT6-mediated methylation of p27 in mice. Human colorectal tumors have lower levels of PPARA messenger RNA and protein than nontumor tissues. Agents that activate PPARα might be developed for chemoprevention or treatment of colon cancer.
Topics: Adenocarcinoma; Animals; Anticarcinogenic Agents; Case-Control Studies; Cell Cycle Proteins; Cell Transformation, Neoplastic; Colon; Colonic Neoplasms; DNA (Cytosine-5-)-Methyltransferase 1; DNA Methylation; Databases, Genetic; Disease Models, Animal; Fenofibrate; Gene Expression Regulation, Neoplastic; Humans; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Nuclear Proteins; PPAR alpha; Protein-Arginine N-Methyltransferases; Signal Transduction
PubMed: 31154022
DOI: 10.1053/j.gastro.2019.05.057 -
Cancer Immunology Research Sep 2021Chronic inflammation is a key driver for colitis-associated colorectal cancer. 5-hydroxytryptamine (5-HT), a neurotransmitter, has been reported to promote inflammation...
Chronic inflammation is a key driver for colitis-associated colorectal cancer. 5-hydroxytryptamine (5-HT), a neurotransmitter, has been reported to promote inflammation in the gastrointestinal tract. However, the mechanism behind this remains unclear. In this study, we found that 5-HT levels, as well as the expression of tryptophan hydroxylase 1 (TPH1), the 5-HT biosynthesis rate-limiting enzyme, were significantly upregulated in colorectal tumor tissues from patients with colorectal cancer, colorectal cancer mouse models, and colorectal cancer cell lines when compared with normal colorectal tissues or epithelial cell lines. Colorectal cancer cell-originated 5-HT enhanced NLRP3 inflammasome activation in THP-1 cells and immortalized bone marrow-derived macrophages (iBMDM) via its ion channel receptor, HTR3A. Mechanistically, HTR3A activation led to Ca influx, followed by CaMKIIα phosphorylation (Thr286) and activation, which then induced NLRP3 phosphorylation at Ser198 (mouse: Ser194) and inflammasome assembling. The NLRP3 inflammasome mediated IL1β maturation, and release upregulated 5-HT biosynthesis in colorectal cancer cells by inducing transcription, revealing a positive feedback loop between 5-HT and NLRP3 signaling. Silencing TPH1 or HTR3A by short hairpin RNA slowed down tumor growth in an established CT26 and iBMDM coimplanted subcutaneous allograft colorectal cancer mouse model, whereas treatment with TPH1 inhibitor 4-chloro-DL-phenylalanine or HTR3A antagonist tropisetron alleviated tumor progression in an azoxymethane/dextran sodium sulfate-induced colorectal cancer mouse model. Addressing the positive feedback loop between 5-HT and NLRP3 signaling could provide potential therapeutic targets for colorectal cancer.
Topics: Animals; Azoxymethane; Cell Line, Tumor; Colitis-Associated Neoplasms; Dextran Sulfate; Gastrointestinal Tract; Humans; Inflammasomes; Inflammation; Interleukin-1beta; Macrophages; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Serotonin; Signal Transduction; Tryptophan Hydroxylase
PubMed: 34285037
DOI: 10.1158/2326-6066.CIR-20-1043 -
EBioMedicine Jul 2023Obesity is a risk factor for colorectal cancer (CRC). The role of gut microbiota in mediating the cancer-promoting effect of obesity is unknown.
BACKGROUND
Obesity is a risk factor for colorectal cancer (CRC). The role of gut microbiota in mediating the cancer-promoting effect of obesity is unknown.
METHODS
Azoxymethane (AOM)-treated, Apc and germ-free mice were gavaged with feces from obese individuals and control subjects respectively. The colonic tumor load and number were recorded at the endpoint in two carcinogenic models. The gut microbiota composition and colonic transcriptome were assessed by metagenomic sequencing and RNA sequencing, respectively. The anticancer effects of bacteria depleted in fecal samples of obese individuals were validated.
FINDINGS
Conventional AOM-treated and Apc mice receiving feces from obese individuals showed significantly increased colon tumor formation compared with those receiving feces from control subjects. AOM-treated mice receiving feces from obese individuals showed impaired intestinal barrier function and significant upregulation of pro-inflammatory cytokines and activation of oncogenic Wnt signaling pathway. Consistently, transferring feces from obese individuals to germ-free mice led to increased colonic cell proliferation, intestinal barrier function impairment, and induction of oncogenic and proinflammatory gene expression. Moreover, germ-free mice transplanted with feces from obese human donors had increased abundance of potential pathobiont Alistipes finegoldii, and reduced abundance of commensals Bacteroides vulgatus and Akkermansia muciniphila compared with those receiving feces from human donors with normal body mass index (BMI). Validation experiments showed that B. vulgatus and A. muciniphila demonstrated anti-proliferative effects in CRC, while A. finegoldii promoted CRC tumor growth.
INTERPRETATION
Our results supported the role of obesity-associated microbiota in colorectal carcinogenesis and identified putative bacterial candidates that may mediate its mechanisms. Microbiota modulation in obese individuals may provide new approaches to prevent or treat obesity-related cancers including CRC.
FUNDING
This work was funded by National Key Research and Development Program of China (2020YFA0509200/2020YFA0509203), National Natural Science Foundation of China (81922082), RGC Theme-based Research Scheme Hong Kong (T21-705/20-N), RGC Research Impact Fund Hong Kong (R4632-21F), RGC-CRF Hong Kong (C4039-19GF and C7065-18GF), RGC-GRF Hong Kong (14110819, 14111621), and NTU Start-Up Grant (021337-00001).
Topics: Humans; Mice; Animals; Gastrointestinal Microbiome; Colonic Neoplasms; Carcinogenesis; Obesity; Azoxymethane; Colorectal Neoplasms; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 37343363
DOI: 10.1016/j.ebiom.2023.104670 -
Gastroenterology Aug 2021The metabolic features and function of intratumoral regulatory T cells (Tregs) are ambiguous in colorectal cancer. Tumor-infiltrating Tregs are reprogrammed to exhibit...
BACKGROUND & AIMS
The metabolic features and function of intratumoral regulatory T cells (Tregs) are ambiguous in colorectal cancer. Tumor-infiltrating Tregs are reprogrammed to exhibit high glucose-depleting properties and adapt to the glucose-restricted microenvironment. The glucose-responsive transcription factor MondoA is highly expressed in Tregs. However, the role of MondoA in colorectal cancer-infiltrating Tregs in response to glucose limitation remains to be elucidated.
METHODS
We performed studies using mice, in which MondoA was conditionally deleted in Tregs, and human colorectal cancer tissues. Seahorse and other metabolic assays were used to assess Treg metabolism. To study the role of Tregs in antitumor immunity, we used a subcutaneous MC38 colorectal cancer model and induced colitis-associated colorectal cancer in mice by azoxymethane and dextran sodium sulfate.
RESULTS
Our analysis of single-cell RNA sequencing data of patients with colorectal cancer revealed that intratumoral Tregs featured low activity of the MondoA-thioredoxin-interacting protein (TXNIP) axis and increased glucose uptake. Although MondoA-deficient Tregs were less immune suppressive and selectively promoted T-helper (Th) cell type 1 (Th1) responses in a subcutaneous MC38 tumor model, Treg-specific MondoA knockout mice were more susceptible to azoxymethane-DSS-induced colorectal cancer. Mechanistically, suppression of the MondoA-TXNIP axis promoted glucose uptake and glycolysis, induced hyperglycolytic Th17-like Tregs, which facilitated Th17 inflammation, promoted interleukin 17A-induced of CD8 T-cell exhaustion, and drove colorectal carcinogenesis. Blockade of interleukin 17A reduced tumor progression and minimized the susceptibility of MondoA-deficient mice to colorectal carcinogenesis.
CONCLUSIONS
The MondoA-TXNIP axis is a critical metabolic regulator of Treg identity and function in the colorectal cancer microenvironment and a promising target for cancer therapy.
Topics: Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Carrier Proteins; Cell Line, Tumor; Colitis-Associated Neoplasms; Colorectal Neoplasms; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Glycolysis; Humans; Lymphocytes, Tumor-Infiltrating; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Signal Transduction; T-Lymphocytes, Regulatory; Th17 Cells; Thioredoxins; Tumor Microenvironment; Mice
PubMed: 33901495
DOI: 10.1053/j.gastro.2021.04.041 -
Journal of Immunology Research 2020Colorectal cancer (CRC) is the fourth leading cause of tumor-related deaths worldwide. In this study, we explored the in vivo effects of quercetin, a plant flavonol from...
Colorectal cancer (CRC) is the fourth leading cause of tumor-related deaths worldwide. In this study, we explored the in vivo effects of quercetin, a plant flavonol from the flavonoid group of polyphenols with antioxidant effects, on colon carcinogenesis induced by azoxymethane/dextran sodium sulfate (AOM/DSS). Thirty mice were randomly assigned into three groups: the control group, the AOM/DSS group, and the quercetin+AOM/DSS group. CRC was induced by AOM injection and a solution of 2% DSS in the drinking water. In the AOM/DSS-induced colon cancer mice model, quercetin treatment dramatically reduced the number and size of colon tumors. In addition, quercetin significantly restored the leukocyte counts by decreasing the inflammation caused by AOM/DSS. We also observed that the expression of oxidative stress markers, such as lipid peroxide (LPO), nitric oxide (NO), superoxide dismutase (SOD), glucose-6-phosphate (G6PD), and glutathione (GSH), could be reduced by quercetin, suggesting that the anti-inflammatory function of quercetin comes from its antioxidant effect. Moreover, potential biomarkers were identified with serum metabolite profiling. Increased levels of 2-hydroxybutyrate, 2-aminobutyrate, and 2-oxobutyrate and decreased levels of gentian violet, indole-3-methyl acetate, N-acetyl-5-hydroxytryptamine, indoxyl sulfate, and indoxyl were also found in the AOM/DSS-treated mice. However, quercetin treatment successfully decreased the levels of 2-hydroxybutyrate, 2-aminobutyrate, 2-oxobutyrate, endocannabinoids, and sphinganine and increased the levels of gentian violet, N-acetyl-5-hydroxytryptamine, indoxyl sulfate, and indoxyl. Together, our data demonstrated that quercetin could maintain relatively potent antitumor activities against colorectal cancer in vivo through its anti-inflammation effect.
Topics: Animals; Antineoplastic Agents; Azoxymethane; Biomarkers, Tumor; Carcinogenesis; Colon; Colorectal Neoplasms; Dextran Sulfate; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Gentian Violet; Humans; Hydroxybutyrates; Mice; Mice, Inbred C57BL; Oxidative Stress; Quercetin; Tumor Burden
PubMed: 32537472
DOI: 10.1155/2020/9242601