Kim S et al. (2008) Mol Cells "Thymidylate synthase and dihydropyrimidine dehydrogenase levels are associated with response to 5-fluorouracil in Caenorhabditis elegans."

Kim S, Park DH, Shim J

[Mol Cells, 2008]

5-Fluorouracil (5-FU), a pyrimidine antagonist, has a long history in cancer treatment. The targeted pyrimidine biosynthesis pathway includes dihydropyrimidine dehydrogenase (DPD), which converts 5-FU to an inactive metabolite, and thymidylate synthase (TS), which is a major target of 5-FU. Using Caenorhabditis elegans as a model system to study the functional and resistance mechanisms of anti-cancer drugs, we examined these two genes in order to determine the extent of molecular conservation between C. elegans and humans. Overexpression of the worm DPD and TS homologs (DPYD-1 and Y110A7A.4, respectively) suppressed germ cell death following 5-FU exposure. In addition, DPYD-1 depletion by RNAi resulted in 5-FU sensitivity, while treatment with Y110A7A.4 RNAi and 5-FU resulted in similar patterns of embryonic death. Thus, the pathway of 5-FU function appears to be highly conserved between C. elegans and humans at the molecular level.

Kim S et al. (2008) Mol Cells "A forward genetic approach for analyzing the mechanism of resistance to the anti-cancer drug, 5-fluorouracil, using Caenorhabditis elegans."

Shim J, Kim S

[Mol Cells, 2008]

Pyrimidine antagonists including 5-Fluorouracil (5-FU) have been used in chemotherapy for cancer patients for over 40 years. 5-FU, especially, is a mainstay treatment for colorectal cancer. It is a pro-drug that is converted to the active drug via the nucleic acid biosynthetic pathway. The metabolites of 5-FU inhibit normal RNA and DNA function, and induce apoptosis of cancer cells. One of the major obstacles to successful chemotherapy is the resistance of cancer cells to anti-cancer drugs. Therefore, it is important to elucidate resistance mechanisms to improve the efficacy of chemotherapy. We have used C. elegans as a model system to investigate the mechanism of resistance to 5-FU, which induces germ cell death and inhibits larval development in C. elegans. We screened 5-FU resistant mutants no longer arrested as larvae by 5-FU. We obtained 18 mutants out of 72,000 F1 individuals screened, and mapped them into three complementation groups. We propose that C. elegans could be a useful model system for studying mechanisms of resistance to anti-cancer drugs.

(2017) Cancer Discov "Bacterial Metabolism Alters the Efficacy of Chemotherapeutics."

[Cancer Discov, 2017]

Bacteria alter the response to the chemotherapeutics 5-FU, FUDR, capecitabine, and CPT in C. elegans.

Hwang IT et al. (2007) Biochem Biophys Res Commun "Drug resistance to 5-FU linked to reactive oxygen species modulator 1."

Kim HJ, Hwang IT, Kim BS, Kim JJ, Yoo YD, Kim JS, Chung YM, Chung JS

[Biochem Biophys Res Commun, 2007]

While acute oxidative stress triggers cell apoptosis or necrosis, persistent oxidative stress induces genomic instability and has been implicated in tumor progression and drug resistance. In a previous report, we demonstrated that reactive oxygen species modulator 1 (Romo1) expression was up-regulated in most cancer cell lines and suggested that increased Romo1 expression might confer chronic oxidative stress to tumor cells. In this study, we show that enforced Romo1 expression induces reactive oxygen species (ROS) production in the mitochondria leading to massive cell death. However, tumor cells that adapt to oxidative stress by increasing manganese superoxide dismutase (MnSOD), Prx I, and Bcl-2 showed drug resistance to 5-FU. To elucidate the relationship between 5-FU-induced ROS production and Romo1 expression, Romo1 siRNA was used to inhibit 5-FU-triggered Romo1 induction. Romo1 siRNA treatment efficiently blocked 5-FU-induced ROS generation, demonstrating that 5-FU treatment stimulated ROS production through Romo1 induction. Based on these results we suggest that cellular adaptive response to Romo1-induced ROS is another mechanism of drug resistance to 5-FU and Romo1 expression may provide a new clinical implication in drug resistance of cancer chemotherapy.

Kumar S et al. (2010) Reprod Toxicol "Anticancer drug 5-fluorouracil induces reproductive and developmental defects in Caenorhabditis elegans."

Michaux G, Morel F, Kumar S, Aninat C

[Reprod Toxicol, 2010]

In order to examine the chronic effects of anticancer drug 5-fluorouracil (5-FU) on reproduction and development, we exploited Caenorhabditis elegans as a model system. We demonstrate that 5-FU induces cell-cycle arrest and apoptosis of germline cells and reduces by approximately 30-40% the number of mitotic nuclei per gonad arm when compared to untreated worms. This drug also affects vulva development, some animals being vulvaless, as well as dysfunction of vulval and egg laying muscles leading to an 8-10 days delay in reproductive time. Interestingly, 5-FU represses levels of mRNA encoding LIN-29, a transcription factor that affects vulva development and egg laying system. Finally, we demonstrate that RNAi-dependent repression of ung-1 gene, which encodes a uracil-DNA glycosylase, partially abolishes 5-FU effects on embryo hatching. Thus, we proposed that C. elegans could be a useful model system for studying the mechanisms by which 5-FU might affect either embryo, adult or organ development.

Kim S et al. (2009) FEBS J "Functional analysis of pyrimidine biosynthesis enzymes using the anticancer drug 5-fluorouracil in Caenorhabditis elegans."

Hwang M, Park DH, Kim S, Kim TH, Shim J

[FEBS J, 2009]

Pyrimidine biosynthesis enzymes function in many cellular processes and are closely associated with pyrimidine antagonists used in cancer chemotherapy. These enzymes are well characterized from bacteria to mammals, but not in a simple metazoan. To study the pyrimidine biosynthesis pathway in Caenorhabditis elegans, we screened for mutants exhibiting resistance to the anticancer drug 5-fluorouracil (5-FU). In several strains, mutations were identified in ZK783.2, the worm homolog of human uridine phosphorylase (UP). UP is a member of the pyrimidine biosynthesis family of enzymes and is a key regulator of uridine homeostasis. C. elegans UP homologous protein (UPP-1) exhibited both uridine and thymidine phosphorylase activity in vitro. Knockdown of other pyrimidine biosynthesis enzyme homologs, such as uridine monophosphate kinase and uridine monophosphate synthetase, also resulted in 5-FU resistance. Uridine monophosphate kinase and uridine monophosphate synthetase proteins are redundant, and show different, tissue-specific expression patterns in C. elegans. Whereas pyrimidine biosynthesis pathways are highly conserved between worms and humans, no human thymidine phosphorylase homolog has been identified in C. elegans. UPP-1 functions as a key regulator of the pyrimidine salvage pathway in C. elegans, as mutation of upp-1 results in strong 5-FU resistance.

Garcia-Gonzalez AP et al. (2017) Cell "Bacterial Metabolism Affects the C.elegans Response to Cancer Chemotherapeutics."

Yilmaz LS, Shrestha S, Andersen EC, Ritter AD, Walhout AJM, Garcia-Gonzalez AP

[Cell, 2017]

The human microbiota greatly affects physiology and disease; however, the contribution of bacteria to the response to chemotherapeutic drugs remains poorly understood. Caenorhabditis elegans and its bacterial diet provide a powerful system to study host-bacteria interactions. Here, we use this system to study how bacteria affect the C.elegans response to chemotherapeutics. We find that different bacterial species can increase the response to one drug yet decrease the effect of another. We perform genetic screens in two bacterial species using three chemotherapeutic drugs: 5-fluorouracil (5-FU), 5-fluoro-2'-deoxyuridine (FUDR), and camptothecin (CPT). We find numerous bacterial nucleotide metabolism genes that affect drug efficacy in C.elegans. Surprisingly, we find that 5-FU and FUDR act through bacterial ribonucleotide metabolism to elicit their cytotoxic effects in C.elegans rather than by thymineless death or DNA damage. Our study provides a blueprint for characterizing the role of bacteria in the host response to chemotherapeutics.

Scott TA et al. (2017) Cell "Host-Microbe Co-metabolism Dictates Cancer Drug Efficacy in C.elegans."

Clayton PT, Herrera-Dominguez L, Cabreiro F, Wilson MP, Scott TA, Typas A, Quintaneiro LM, Pessia A, Sudiwala S, Norvaisas P, Velagapudi V, Leung KY, Mills PB, Greene NDE, Bryson K, Lui PP

[Cell, 2017]

Fluoropyrimidines are the first-line treatment for colorectal cancer, but their efficacy is highly variablebetween patients. We queried whether gut microbes,a known source of inter-individual variability, impacted drug efficacy. Combining two tractable genetic models, the bacterium E.coli and the nematode C.elegans, we performed three-way high-throughput screens that unraveled the complexity underlying host-microbe-drug interactions. We report that microbes can bolster or suppress the effects of fluoropyrimidines through metabolic drug interconversion involving bacterial vitamin B6, B9, and ribonucleotide metabolism. Also, disturbances in bacterial deoxynucleotide pools amplify 5-FU-induced autophagy and cell death in host cells, an effect regulated by the nucleoside diphosphate kinase ndk-1. Our data suggest a two-way bacterial mediation of fluoropyrimidine effects on host metabolism, which contributes to drug efficacy. These findings highlight the potentialtherapeutic power of manipulating intestinal microbiota to ensure host metabolic health and treat disease.

Kato Y et al. (2016) Genes Genet Syst "FUdR extends the lifespan of the short-lived AP endonuclease mutant in Caenorhabditis elegans in a fertility-dependent manner."

Kato Y, Miyaji M, Zhang-Akiyama QM

[Genes Genet Syst, 2016]

The anticancer drug 5-fluorouracil (5-FU) and its metabolite 5-fluoro-2'-deoxyuridine (FUdR) inhibit thymidylate synthase and induce uracil bases in DNA. FUdR is commonly used for inhibiting fertility when measuring the lifespan of the nematode Caenorhabditis elegans. However, it is not known whether DNA damage induced by FUdR affects lifespan. EXO-3 is an apurinic/apyrimidinic endonuclease in C. elegans, and we reported previously that deletion of the exo-3 gene causes reproductive abnormalities and decreased lifespan. In this study, we found that FUdR extended the lifespan of exo-3 mutants. We measured the lifespan of multiple germline mutants to examine whether this lifespan extension effect was dependent on fertility. In the presence of a fem-1 mutation, which causes a deficiency in sperm production, FUdR did not extend the lifespan of the exo-3 mutant. In glp-1 mutants, which do not develop gonads, the exo-3 mutant was not short-lived, and FUdR did not extend its lifespan. These results suggest that the lifespan extension effect of FUdR depends on fertility and the presence of gonads. fem-3 mutants, which do not produce oocytes had increased lifespan in the presence of FUdR, independent of the exo-3 mutation. It is possible that the fem-3 mutant was susceptible to the lifespan extension effect of FUdR. From these results, we suggest that FUdR affects the lifespan of C. elegans in two ways: by interfering with fertility, which extends lifespan, and by inducing DNA base damage, which reduces lifespan.

Zhang S et al. (2015) Iran J Public Health "The Analysis of Gene Expression on Fertility Decline in Caenorhabditis elegans after the Treatment with 5-Fluorouracil."

Zhang Y, Bao G, Fu X, Wu J, Wang X, Lu Z, Wang M, Liu X, Jing T, Liang H, Zhang S, Chen G

[Iran J Public Health, 2015]

BACKGROUND: 5-Fluorouracil could lead to a decline in fertility in Caenorhabditis elegans. The aim of this study was to describe the mechanisms underlying such an altered fertility phenotype and to illustrate the specific genes and pathways that are involved in the related phenotypic changes in C. elegans. METHODS: We isolated total RNA from the samples and used a new method called Digital Gene Expression (DGE), which can rapidly identify genes with altered transcript levels. The random genes were confirmed by real-time RT-PCR. RESULTS: We analyzed the results of two methods to draw conclusions based on a comparison between C. elegans and other harmful parasites. Compared with controls, 1147 genes were up-regulated, and 1067 were down-regulated. Overall, 101 up-regulated genes had a log2 ratio higher than 8, whereas the log2 ratio of 141 down-regulated genes was higher than 8. After mapping to the reference database, 4 pathways were confirmed to be involved in this phenomenon, with statistically significant participation from 19 genes. CONCLUSION: For the first time, the transcript sequence of 5-Fu-treated worms and controls was detected. We found that 4 possible pathways, i.e., ECM-receptor interaction pathway, TGF-beta signaling pathway, Focal adhesion and Hypertrophic cardiomyopathy, may be involved in the number decline in the embryos of C. elegans. Specifically, the ECM-receptor interaction pathway and Focal adhesion may be very important pathways that alter the reproduction of C. elegans.