levoleucovorin and Disease-Models--Animal

Late detection, compromised immune system, and chemotherapy resistance underlie the poor patient prognosis for pancreatic ductal adenocarcinoma (PDAC) patients, making it the 3

Topics: Adaptive Immunity; Animals; Antineoplastic Agents, Immunological; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow; Cancer Vaccines; Carcinoma, Pancreatic Ductal; Chemotherapy, Adjuvant; Clinical Trials as Topic; Combined Modality Therapy; Disease Models, Animal; Disease-Free Survival; Fluorouracil; Humans; Immunity, Innate; Immunotherapy; Irinotecan; Leucovorin; Lymph Node Excision; Lymph Nodes; Mice; Mice, Transgenic; Neoadjuvant Therapy; Oxaliplatin; Pancreas; Pancreatectomy; Pancreatic Neoplasms; Spleen; Splenectomy; T-Lymphocytes; Transplantation, Autologous; Tumor Escape; Tumor Microenvironment; United States

The results from preclinical studies using murine tumor models show that the combination of docetaxel (Taxotere) and fluorouracil (5-FU) is highly synergistic. Phase I studies in patients with advanced solid tumors indicate that 60 mg/m2 of docetaxel administered as a 1-hour intravenous infusion followed by a daily intravenous bolus of 300 mg/m2 of 5-FU on days 1 through 5 is the recommended dose for phase II studies. Preliminary results from another phase I study using a continuous infusion regimen for 5-FU suggest that 85 mg/m2 of docetaxel administered as a 1-hour intravenous infusion followed by continuous infusion of 750 mg/m2 per day of 5-FU on days 1 through 5 may be the recommended dose for phase II studies. As expected, dose-limiting toxicities included neutropenia and mucositis. Ongoing phase I/II and II studies are investigating the combination of docetaxel with continuous infusion of 5-FU in patients with metastatic breast cancer and with cisplatin (Platinol) and continuous infusion of 5-FU, with and without leucovorin, in patients with head and neck cancer. Preliminary results are encouraging and warrant further study.

Topics: Adult; Aged; Animals; Antidotes; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Disease Models, Animal; Docetaxel; Dose-Response Relationship, Drug; Drug Synergism; Female; Fluorouracil; Head and Neck Neoplasms; Humans; Infusions, Intravenous; Leucovorin; Mice; Middle Aged; Mucous Membrane; Neoplasms; Neutropenia; Paclitaxel; Taxoids

In vitro results have clearly demonstrated that leucovorin (LV) can enhance the growth inhibitory effects of 5-fluorouracil (5FU) but in vivo potentiation of the antitumor effect of 5FU by LV has not yet been defined in animal models. The antitumor effect and the toxicity of the LV-5FU combination was studied in mice bearing the colon carcinomas, Colon 26 and Colon 38. Mice were treated weekly with 5FU at the maximum tolerated dose (100 mg/kg) alone or with LV at different doses and schedules. Pretreatment with LV followed 1 hr later by a second LV injection together with 5FU clearly potentiated the antitumor effect of 5FU in both murine tumor lines. Comparable results were obtained with total LV doses of 100 and 200 mg/kg. The effect of 5FU pretreatment was studied by randomization of 5FU pretreated Colon 38-bearing mice in 2 groups, one treated with 5FU and the other with LV-LV + 5FU. Again, LV potentiated the effect of 5FU. Also in a Colon 38 tumor which had developed resistance against 5FU and which was reimplanted, LV potentiated the antitumor activity of 5FU. Weight loss of the combination was slightly higher than for 5FU alone. A moderate leukopenia (nadir 40%) and mild anemia were observed, which were less than for 5FU alone. The combination did not cause thrombocytopenia. In conclusion, LV can potentiate the therapeutic efficacy of 5FU in murine colon carcinoma.

Topics: Adenocarcinoma; Animals; Carcinoma; Colonic Neoplasms; Disease Models, Animal; Drug Synergism; Female; Fluorouracil; Humans; Leucovorin; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL

Previously published work has demonstrated that combining gemcitabine with irreversible electroporation (IRE) results in increased drug delivery to pancreatic adenocarcinoma cells in vivo. This study assessed the efficacy of IRE + gemcitabine and IRE + FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin), the impact of the superior regimen on survival, and the safety of electrochemotherapy in human subjects.. Histologic analysis was performed after in vitro and in vivo treatment of S2013 and Panc-1 pancreatic cancer cells and S2013 orthotopic tumors, respectively, and levels of apoptotic machinery and cell cycle proteins were evaluated using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot.. Electrochemotherapy (ECT) with IRE and FOLFIRINOX resulted in increased tumor cells apoptosis compared with gemcitabine, gemcitabine + IRE, and FOLFIRINOX alone, and significantly improved overall survival when compared with mice treated with IRE or FOLFIRINOX. Increased tumor cell apoptosis, caspase-3 mRNA, active caspase-3 protein, and decreased cell proliferation were noted at the time of death or euthanasia in the ECT group compared with folinic acid alone. In five patients, ECT with either FOLFIRINOX or gemcitabine was well-tolerated and resulted in no dose-limiting toxicities.. ECT thus results in synergistic antitumor activity compared with either treatment modality used alone, resulting in increased tumor cell apoptosis as well as decreased tumor cell proliferation and improved overall survival. Pilot data suggest that ECT represents a promising modality for the treatment of patients with locally advanced pancreatic cancer.. The human subject portion of this work was conducted as part of an investigator-initiated clinical trial at the University of Louisville (NCT03484299).

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Deoxycytidine; Disease Models, Animal; Electrochemotherapy; Fluorouracil; Gemcitabine; Humans; Irinotecan; Leucovorin; Mice; Oxaliplatin; Pancreatic Neoplasms; Treatment Outcome

Chemotherapy-induced diarrhea occurs secondary to mucosal inflammation and may be cyclooxygenase-2 mediated. Cyclooxygenase-2 inhibitors may ameliorate chemotherapy-induced mucosal toxicity and enhance its antitumor effect. We investigated this hypothesis in the Ward colorectal cancer rat model and in a phase I clinical study.. In the Ward rat model, irinotecan was given daily x 3 or weekly x 4 with or without celecoxib. In the phase I clinical study, we planned to escalate the dose of irinotecan in the FOLFIRI regimen (irinotecan, 5-fluorouracil, and leucovorin) with a fixed dose of celecoxib. Irinotecan was escalated in four dose levels: 180, 200, 220, and 260 mg/m2. Celecoxib was administered as 400 mg, twice daily starting on day 2 of cycle 1. Pharmacokinetics of irinotecan, SN-38, and SN-38G were obtained on days 1 and 14. A standard 3+3 dose escalation scheme was used. Plasma concentrations of irinotecan, SN-38, and SN-38G were measured using high-pressure liquid chromatography.. Celecoxib ameliorated diarrhea, weight loss, and lethality and resulted in synergistic antitumor effect in the rat model. Twelve patients with advanced cancers were enrolled and evaluable for dose-limiting toxicity (DLT). Diarrhea was the cause for discontinuation in one. Grade 2 and 3 diarrhea occurred in three and two patients, respectively. One patient had DLT at dose level 2 (grade 3 diarrhea). Two had a DLT at DL3 (G3 emesis and myocardial infarct). Celecoxib had limited influence on the pharmacokinetics of irinotecan in this data set.. Maximum tolerated dose of irinotecan in FOLFIRI schedule with celecoxib is 200 mg/m2.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Celecoxib; Colorectal Neoplasms; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Fluorouracil; Glucuronates; Humans; Intestinal Mucosa; Irinotecan; Leucovorin; Male; Maximum Tolerated Dose; Mucositis; Neoplasm Transplantation; Neoplasms, Experimental; Pyrazoles; Rats; Rats, Inbred F344; Sulfonamides

Both modified FOLFIRINOX (mFFX) and gemcitabine/nab-paclitaxel chemotherapy regimens have been shown to improve clinical outcomes in patients with pancreatic cancer, and are often used interchangeably as the standard of care. Preclinical studies often do not use these regimens, since administering these multiagent approaches can be difficult. In this study, we assessed the feasibility of administering these two chemotherapy regimens in spontaneous pancreatic tumors using KPC mice with the ultimate goal of advancing preclinical studies.. In total, 92 mice were included. The median OS in the FFX X2 group was slightly longer that the median OS in the FFX X1 group (15 days vs 11 days, P = 0.003). Mice in the GEM/AB X2 group had longer OS when compared to mice in the GEM/AB X1 group (33.5 vs 13 days, P = 0.001). Mice treated with chemotherapy survived longer than untreated control animals (median OS: 6.5 days, P < 0.001). Moreover, in mice treated with chemotherapy, mice that received 2 cycles of GEM/AB X2 had the longest survival, while the FFX X1 group had the poorest OS (P < 0.001). The addition of chemotherapy was associated with reduced number of myeloid and lymphoid cell types, except for CD4 + cells whose levels were largely unaltered only in tumors treated with gemcitabine/nab-paclitaxel. Lastly, chemotherapy followed by consolidative SBRT trended towards increased local control and survival.. We demonstrate the utility and feasibility of clinically relevant mFOLFIRINOX and gemcitabine/nab-paclitaxel in preclinical models of pancreatic cancer.

Topics: Albumins; Animals; Antineoplastic Combined Chemotherapy Protocols; Deoxycytidine; Disease Models, Animal; Feasibility Studies; Fluorouracil; Gemcitabine; Humans; Irinotecan; Leucovorin; Mice; Oxaliplatin; Paclitaxel; Pancreatic Neoplasms

Some clinical studies have indicated the patients with Alzheimer's disease (AD) display an increased risk of cardiovascular disease (CVD). Here, to examine the relationship between AD and CVDs, we investigated the changes in heart function in triple-transgenic late-stage AD model mice (3× Tg-AD; APPSwe, PS1M146V, and tauP301L). We fed the AD mice folic acid (FA) or folinic acid (FN) and analyzed the protective effects of the compounds on the heart; specifically, 20-month-old triple-transgenic AD mice, weighing 34-55 g, were randomly allocated into three groups-the AD, AD + FA, and AD + FN groups-and subject to gastric feeding with FA or FN once daily at 12 mg/kg body weight (BW) for 3 months. Mouse BWs were assessed throughout the trial, at the end of which the animals were sacrificed using carbon dioxide suffocation. We found that BW, whole-heart weight, and left-ventricle weight were reduced in the AD + FA and AD + FN groups as compared with the measurements in the AD group. Furthermore, western blotting of excised heart tissue revealed that the levels of the hypertrophy-related protein markers phospho(p)-p38 and p-c-Jun were markedly decreased in the AD + FA group, whereas p-GATA4, and ANP were strongly reduced in the AD + FN group. Moreover, the fibrosis-related proteins uPA, MMP-2, MEK1/2 and SP-1 were decreased in the heart in both AD + FN group. In summary, our results indicate that FA and FN can exert anti-cardiac hypertrophy and fibrosis effects to protect the heart in aged triple-transgenic AD model mice, particular in FN.

Topics: Aged; Alzheimer Disease; Animals; Cardiomegaly; Disease Models, Animal; Fibrosis; Folic Acid; Humans; Leucovorin; Mice; Mice, Transgenic

Pancreatic cancer is one of the most recalcitrant cancers, and more effective therapy is needed. Pre-clinical studies have shown that patient-derived orthotopic xenograft (PDOX) mouse models of pancreatic cancer are effectively treated with oral recombinant methioninase (o-rMETase).. A 62-year-old woman diagnosed with stage IV pancreatic cancer was treated with the combination of 5-fluorouracil/leucovorin, irinotecan, and oxaliplatinum (FOLFIRINOX) every two weeks and o-rMETase twice a day as a supplement. The patient was also on a low-methionine diet. Disease progression was monitored by CA19-9 and computed tomography. The patient initially responded to FOLFIRINOX, shown by a great reduction in CA19-9 levels, with tumor shrinkage shown by computed tomography. The patient began taking o-rMETase and went on a low-methionine diet one year after diagnosis which she has maintained without side effects for 7 months. The patient's CA19-9 level and tumor size remain stable 19 months after diagnosis. The patient is alive and has maintained a high performance status. Historical data show that less than 5% of stage IV pancreatic-cancer patients on FOLFIRINOX have stable disease 1.5 years after diagnosis.. The combination of o-rMETase and FOLFIRINOX may be synergistic in stage IV pancreatic cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; CA-19-9 Antigen; Carbon-Sulfur Lyases; Disease Models, Animal; Female; Fluorouracil; Humans; Irinotecan; Leucovorin; Methionine; Mice; Mice, Nude; Oxaliplatin; Pancreatic Neoplasms; Xenograft Model Antitumor Assays

FOLFOX is a combinational regimen of folinic acid (FnA, FOL), fluorouracil (5-Fu, F) and oxaliplatin (OxP, OX), and has been long considered as the standard treatment of colorectal cancer (CRC) and hepatocellular carcinoma (HCC). Recent developments of nano delivery systems have provided profound promise for improving anticancer efficacy and alleviating side effects of FOLFOX. Previously, a nanoformulation (termed Nano-Folox) containing OxP derivative and FnA was developed in our laboratory using nanoprecipitation technique. Nano-Folox induced OxP-mediated immunogenic cell death (ICD)-associated antitumor immunity, which significantly suppressed tumor growth in the orthotopic CRC mouse model when administrated in combination with free 5-Fu.. A nanoformulation (termed Nano-FdUMP) containing FdUMP (5-Fu active metabolite) was newly developed using nanoprecipitation technique and used in combination with Nano-Folox for CRC and HCC therapies.. Synergistic efficacy was achieved in orthotopic CRC and HCC mouse models. It resulted mainly from the fact that Nano-FdUMP mediated the formation of reactive oxygen species (ROS), which promoted the efficacy of ICD elicited by Nano-Folox. In addition, combination of Nano-Folox/Nano-FdUMP and anti-PD-L1 antibody significantly inhibited CRC liver metastasis, leading to long-term survival in mice.. This study provides proof of concept that combination of two nano delivery systems can result in successful FOLFOX-associated CRC and HCC therapies. Further optimization in terms of dosing and timing will enhance clinical potential of this combination strategy for patients.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; B7-H1 Antigen; Carcinoma, Hepatocellular; Cell Line, Tumor; Colorectal Neoplasms; Disease Models, Animal; Drug Compounding; Drug Synergism; Female; Fluorodeoxyuridylate; Fluorouracil; Immunogenic Cell Death; Immunotherapy; Leucovorin; Liver Neoplasms; Mice, Inbred BALB C; Mice, Nude; Nanoparticles; Neoplasm Metastasis; Organoplatinum Compounds; Reactive Oxygen Species; Tissue Distribution

FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin), a 5-fluorouracil (5-FU)-based chemotherapy regimen, is one of most common therapeutic regimens for colorectal cancer. However, intestinal mucositis is a common adverse effect for which no effective preventive strategies exist. Moreover, the efficacy and the safety of fecal microbiota transplants (FMT) in cancer patients treated with anti-neoplastic agents are still scant. We investigated the effect of FMT on FOLFOX-induced mucosal injury. BALB/c mice implanted with syngeneic CT26 colorectal adenocarcinoma cells were orally administered FMT daily during and two days after five-day injection of FOLFOX regimen for seven days. Administration of FOLFOX significantly induced marked levels of diarrhea and intestinal injury. FMT reduced the severity of diarrhea and intestinal mucositis. Additionally, the number of goblet cells and zonula occludens-1 decreased, while apoptotic and NF-κB-positive cells increased following FOLFOX treatment. The expression of toll-like receptors (TLRs), MyD88, and serum IL-6 were upregulated following FOLFOX treatment. These responses were attenuated following FMT. The disrupted fecal gut microbiota composition was also restored by FMT after FOLFOX treatment. Importantly, FMT did not cause bacteremia and safely alleviated FOLFOX-induced intestinal mucositis in colorectal cancer-bearing mice. The putative mechanism may involve the gut microbiota TLR-MyD88-NF-κB signaling pathway in mice with implanted colorectal carcinoma cells.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Colorectal Neoplasms; Disease Models, Animal; Fecal Microbiota Transplantation; Fluorouracil; Gastrointestinal Microbiome; Gene Expression Regulation, Neoplastic; Heterografts; Humans; Intestinal Diseases; Intestines; Leucovorin; Mice; Organoplatinum Compounds; Oxaliplatin; Toll-Like Receptors

Toxoplasma gondii is a protozoan that has great genetic diversity and is prevalent worldwide. In 2018, an outbreak of toxoplasmosis occurred in Santa Maria, Brazil, which was considered the largest outbreak ever described in the world. This paper describes the isolation and molecular characterization of Toxoplasma gondii from the placenta of two pregnant women with acute toxoplasmosis who had live births and were receiving treatment for toxoplasmosis during the outbreak. For this, placental tissue samples from two patients underwent isolation by mice bioassay, conventional PCR and genotyping using PCR-RFLP with twelve markers. Both samples were positive in isolation in mice. The isolate was lethal to mice, suggesting high virulence. In addition, the samples were positive in conventional PCR and isolates submitted to PCR-RFLP genotyping presented an atypical genotype, which had never been described before. This research contributes to the elucidation of this great outbreak in Brazil.

Topics: Animals; Brazil; Coccidiostats; Disease Models, Animal; Disease Outbreaks; Female; Genotype; Humans; Leucovorin; Live Birth; Mice; Placenta; Polymorphism, Restriction Fragment Length; Pregnancy; Pregnancy Complications, Infectious; Pyrimethamine; Sulfadiazine; Toxoplasma; Toxoplasmosis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies. TGF-β is strongly expressed in both the epithelial and stromal compartments of PDAC, and dysregulation of TGF-β signalling is a frequent molecular disturbance in PDAC progression and metastasis. In this study, we investigated whether blockade of TGF-β signalling synergizes with nal-IRI/5-FU/LV, a chemotherapy regimen for malignant pancreatic cancer, in an orthotopic pancreatic tumour mouse model. Compared to nal-IRI/5-FU/LV treatment, combining nal-IRI/5-FU/LV with vactosertib, a TGF-β signalling inhibitor, significantly improved long-term survival rates and effectively suppressed invasion to surrounding tissues. Through RNA-sequencing analysis, we identified that the combination treatment results in robust abrogation of tumour-promoting gene signatures and positive enrichment of tumour-suppressing and apoptotic gene signatures. Particularly, the expression of tumour-suppressing gene Ccdc80 was induced by vactosertib and further induced by vactosertib in combination with nal-IRI/5-FU/LV. Ectopic expression of CCDC80 suppressed migration and colony formation concomitant with decreased expression of epithelial-to-mesenchymal transition (EMT) markers in pancreatic cancer cells. Collectively, these results indicate that combination treatment of vactosertib with nal-IRI/5-FU/LV improves overall survival rates in a mouse model of pancreatic cancer by suppressing invasion through CCDC80. Therefore, combination therapy of nal-IRI/5-FU/LV with vactosertib could provide clinical benefits to pancreatic cancer patients.

Topics: Aniline Compounds; Animals; Antineoplastic Combined Chemotherapy Protocols; Carcinogenesis; Cell Line, Tumor; Cell Movement; Disease Models, Animal; Drug Synergism; Epithelial-Mesenchymal Transition; Fluorouracil; Gene Expression Regulation, Neoplastic; Irinotecan; Leucovorin; Liposomes; Mice, Inbred C57BL; Nanoparticles; Neoplasm Invasiveness; Pancreatic Neoplasms; Signal Transduction; Survival Analysis; Transcriptome; Transforming Growth Factor beta; Triazoles; Tumor Stem Cell Assay; Up-Regulation

FOLFOX chemotherapy (CTx) is used for the treatment of colorectal liver metastasis (CRLM). Side effects include rare cardiotoxicity, which may limit the application of FOLFOX. Currently, there is no effective strategy to prevent FOLFOX-induced cardiotoxicity. Glycine has been shown to protect livers from CTx-induced injury and oxidative stress, and it reduces platelet aggregation and improves microperfusion. This study tested the hypothesis of glycine being cardioprotective in a rat model of FOLFOX in combination with CRLM.. The effect of glycine was tested in vitro on human cardiac myocytes (HCMs). To test glycine in vivo Wag/Rij rats with induced CRLM were treated with FOLFOX ±5% dietary glycine. Left ventricle ejection fraction (LVEF), myocardial fibrosis, and apoptosis, also heart fatty acid binding protein (h-FABP) and brain natriuretic peptide levels were monitored. PCR analysis for Collagen type I, II, and brain natriuretic peptide (BNP) in the heart muscle was performed.. In vitro glycine had no effect on HCM cell viability. Treatment with FOLFOX resulted in a significant increase of h-FABP levels, increased myocardial fibrosis, and apoptosis as well as increased expression of type I Collagen. Furthermore, FOLFOX caused a decrease of LVEF by 10% (. Data presented here demonstrate for the first time that dietary glycine protects the heart against FOLFOX-induced injury during treatment for CRLM.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Colorectal Neoplasms; Diet; Disease Models, Animal; Fluorouracil; Glycine; Heart Injuries; Leucovorin; Liver Neoplasms; Male; Organoplatinum Compounds; Rats

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Disease Models, Animal; Electrochemotherapy; Electroporation; Fluorouracil; Humans; Irinotecan; Leucovorin; Mice; Oxaliplatin; Pancreatic Neoplasms

Mitochondrial folate enzyme ALDH1L2 (aldehyde dehydrogenase 1 family member L2) converts 10-formyltetrahydrofolate to tetrahydrofolate and CO. We generated Aldh1l2 knockout (KO) mouse model, characterized its phenotype, tissue histology, and levels of reduced folate pools and applied untargeted metabolomics to determine metabolic changes in the liver, pancreas, and plasma caused by the enzyme loss. We have also used NanoString Mouse Inflammation V2 Code Set to analyze inflammatory gene expression and evaluate the role of ALDH1L2 in the regulation of inflammatory pathways.. Both male and female Aldh1l2 KO mice were viable and did not show an apparent phenotype. However, H&E and Oil Red O staining revealed the accumulation of lipid vesicles localized between the central veins and portal triads in the liver of Aldh1l2. The ALDH1L2 function is important for CoA-dependent pathways including β-oxidation, TCA cycle, and bile acid biosynthesis. The role of ALDH1L2 in the lipid metabolism explains why the loss of this enzyme is associated with neuro-cutaneous diseases. On a broader scale, our study links folate metabolism to the regulation of lipid homeostasis and the energy balance in the cell.

Topics: Adenosine Triphosphate; Animals; Disease Models, Animal; Female; Humans; Leucovorin; Lipid Metabolism; Male; Metabolomics; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; NADP; Oxidoreductases Acting on CH-NH Group Donors; Sjogren-Larsson Syndrome; Tetrahydrofolates

Colorectal cancer (CRC) is one of the most common forms of cancer worldwide. The tumor microenvironment plays a key role in promoting the occurrence of chemoresistance in solid cancers. Effective targets to overcome resistance are necessary to improve the survival and prognosis of CRC patients. This study aimed to evaluate the molecular mechanisms of the tumor microenvironment that might be involved in chemoresistance in patients with CRC.. We evaluated the effects of CCL20 on chemoresistance of CRC by recruitment of regulatory T cells (Tregs) in vitro and in vivo.. We found that the level of CCL20 derived from tumor cells was significantly higher in Folfox-resistant patients than in Folfox-sensitive patients. The high level of CCL20 was closely associated with chemoresistance and poor survival in CRC patients. Among the drugs in Folfox chemotherapy, we confirmed that 5-FU increased the expression of CCL20 in CRC. Moreover, CCL20 derived from 5-FU-resistant CRC cells promoted recruitment of Tregs. Tregs further enhanced the chemoresistance of CRC cells to 5-FU. FOXO1/CEBPB/NF-κB signaling was activated in CRC cells after 5-FU treatment and was required for CCL20 upregulation mediated by 5-FU. Furthermore, CCL20 blockade suppressed tumor progression and restored 5-FU sensitivity in CRC. Lastly, the expression of these signaling molecules mediating chemoresistance was closely correlated with poor survival of CRC patients.. CRC cell-secreted CCL20 can recruit Tregs to promote chemoresistance via FOXO1/CEBPB/NF-κB signaling, indicating that the FOXO1/CEBPB/NF-κB/CCL20 axis might provide a promising target for CRC treatment.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; CCAAT-Enhancer-Binding Protein-beta; Cell Line, Tumor; Cell Proliferation; Chemokine CCL20; Colorectal Neoplasms; Disease Models, Animal; Drug Resistance, Neoplasm; Female; Fluorouracil; Forkhead Box Protein O1; HCT116 Cells; Humans; Leucovorin; Male; Mice; Mice, SCID; Middle Aged; NF-kappa B; Organoplatinum Compounds; Signal Transduction; T-Lymphocytes, Regulatory; Transfection; Xenograft Model Antitumor Assays

Topics: Adenocarcinoma; Allografts; Animals; Antineoplastic Combined Chemotherapy Protocols; Autografts; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Drug Combinations; Fluorouracil; Humans; Irinotecan; Kinetics; Leucovorin; Male; Mice, Inbred C57BL; Organometallic Compounds; Oxaliplatin; Pancreatic Neoplasms; Phenotype; Transplantation, Heterotopic

Folic acid is an essential vitamin participating in DNA synthesis and repair. Recently folic acid has been shown to stimulate DNA-repair capacity in dermal fibroblasts in response to injury. Thus, the present study aimed to investigate the effects of topical folinic acid, a 5-formyl derivative of tetrahydrofolic acid, on wound healing using rat wound model.. A rat wound model was established, and the wound healing was evaluated by macroscopic and histological analyses among vehicle control, 2.5% folinic acid, 1% folinic acid, and dexpanthenol treatment groups. While an image-analysis program was used to evaluate macroscopic wound closure, connective tissue properties, mast cell numbers, and the expressions of matrix metalloproteinase 1 (MMP-1) and 9 (MMP-9) were evaluated by microscopy.. The 2.5% folinic acid-treated group exhibited enhanced wound healing by increased reepithelialization, neo-vessel formation, inflammatory cell migration, collagen deposition and progressive mast cell increase. Furthermore, 2.5% folinic acid induced higher expressions of MMP-1 and MMP-9.. Folinic acid enhances both macroscopic and microscopic wound healing in rat wound model.

Topics: Administration, Topical; Animals; Dermis; Disease Models, Animal; Leucovorin; Male; Mast Cells; Matrix Metalloproteinase 1; Matrix Metalloproteinase 9; Rats, Sprague-Dawley; Wound Healing

Colorectal cancer is a major cancer type worldwide. 5-fluorouracil, often given with leucovorin, is the most commonly used drug in colorectal cancer chemotherapy, yet development of drug resistance to 5-fluorouracil in colorectal cancer cells is the primary cause of chemotherapy failure. Most patients receiving intravenous 5-fluorouracil develop side effects. Leucovorin, due to its vitamin-like profile, has few side-effects. Drug repurposing is the application of approved drugs to treat new indications. In this study, we performed a novel drug-repurposing screening to identify Food and Drug Administration-approved chemotherapeutic compounds possessing synergistic activity with leucovorin against colorectal cancer cells. We found that the combination of bortezomib and leucovorin enhanced caspase activation and increased apoptosis in colorectal cancer cells better than either agent alone. Further, the synergistic induction of apoptosis and inhibition of tumor growth were also observed in mouse colorectal cancer xenografts. These data support leucovorin enhances the anti-cancer effect of bortezomib and present this novel combinatorial treatment against colorectal cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Bortezomib; Caspases; Cell Line, Tumor; Cell Survival; Colorectal Neoplasms; Disease Models, Animal; DNA Damage; Drug Synergism; G2 Phase Cell Cycle Checkpoints; Humans; Leucovorin; Mice; Proteasome Inhibitors; Signal Transduction

The combination of folinate salts to 5-fluoruracil (5-FU)-based schedules is an established clinical routine in the landscape of colorectal cancer treatment. The aim of this study was to investigate the pharmacological differences between the sequential administration of folinate salts (1 h before, as in clinical routine) followed by 5-FU and the simultaneous administration of both drugs. Proliferation and apoptotic assays were performed on human colon cancer cells exposed to 5-FU, calcium (CaLV), or disodium (NaLV) levofolinate or their simultaneous and sequential combination for 24 and 72 h. TYMS and SLC19A1 gene expression was performed with real-time PCR. In vivo experiments were performed in xenografted nude mice, which were treated with 5-FU escalating doses and CaLV or NaLV alone or in simultaneous and sequential combination. The simultaneous combination of folinate salts and 5-FU was synergistic (NaLV) or additive (CaLV) in a 24-h treatment in both cell lines. In contrast, the sequential combination of both folinate salts and 5-FU was antagonistic at 24 and 72 h. The simultaneous combination of 5-FU and NaLV or CaLV inhibited TYMS gene expression at 24 h, whereas the sequential combination reduced SLC19A1 gene expression. In vivo experiments confirmed the enhanced antitumor activity of the 5-FU + NaLV simultaneous combination with a good toxicity profile, whereas the sequential combination with CaLV failed to potentiate 5-FU activity. In conclusion, only the simultaneous, but not the consecutive, in vitro and in vivo combination of 5-FU and both folinate salt formulations potentiated the antiproliferative effects of the drugs.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Fluorouracil; Humans; Leucovorin; Male; Mice; Reduced Folate Carrier Protein; Thymidylate Synthase; Time Factors; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Cetuximab is a monoclonal antibody that is effective in the treatment of metastatic colorectal cancer (mCRC). Cetuximab blocks epidermal growth factor receptor (EGFR)-ligand interaction and inhibits downstream RAS-ERK activation. However, only some activating mutations in RAS affect cetuximab efficacy, and it is not clear what else mediates treatment success. Here we hypothesized that cetuximab induces immunogenic cell death (ICD) that activates a potent antitumor response. We found that cetuximab, in combination with chemotherapy, fostered ICD in CRC cells, which we measured via the endoplasmic reticulum (ER) stress response and an increase in phagocytosis by dendritic cells. ICD induction depended on the mutational status of the EGFR signaling pathway and on the inhibition of the splicing of X-box binding protein 1 (XBP1), an unfolded protein response (UPR) mediator. We confirmed the enhanced immunogenicity elicited by cetuximab in a mouse model of human EGFR-expressing CRC. Overall, we demonstrate a new, immune-related mechanism of action of cetuximab that may help to tailor personalized medicine.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Calreticulin; Camptothecin; Cell Death; Cell Line, Tumor; Cetuximab; Colorectal Neoplasms; Dendritic Cells; Disease Models, Animal; Endoplasmic Reticulum Stress; Fluorouracil; HCT116 Cells; HT29 Cells; Humans; Indoles; Irinotecan; Leucovorin; Mice; Panitumumab; Phagocytosis; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Pyridones; Pyrimidinones; Sulfonamides; Unfolded Protein Response; Vemurafenib; X-Box Binding Protein 1

To assess intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for monitoring early efficacy of chemotherapy in a human gastric cancer mouse model.. IVIM-DWI was performed with 12 b-values (0-800 s/mm(2)) in 25 human gastric cancer-bearing nude mice at baseline (day 0), and then they were randomly divided into control and 1-, 3-, 5- and 7-d treatment groups (n = 5 per group). The control group underwent longitudinal MRI scans at days 1, 3, 5 and 7, and the treatment groups underwent subsequent MRI scans after a specified 5-fluorouracil/calcium folinate treatment. Together with tumor volumes (TV), the apparent diffusion coefficient (ADC) and IVIM parameters [true water molecular diffusion coefficient (D), perfusion fraction (f) and pseudo-related diffusion coefficient (D(*))] were measured. The differences in those parameters from baseline to each measurement (ΔTV%, ΔADC%, ΔD%, Δf% and ΔD(*)%) were calculated. After image acquisition, tumor necrosis, microvessel density (MVD) and cellular apoptosis were evaluated by hematoxylin-eosin (HE), CD31 and terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining respectively, to confirm the imaging findings. Mann-Whitney test and Spearman's correlation coefficient analysis were performed.. The observed relative volume increase (ΔTV%) in the treatment group were significantly smaller than those in the control group at day 5 (ΔTVtreatment% = 19.63% ± 3.01% and ΔTVcontrol% = 83.60% ± 14.87%, P = 0.008) and day 7 (ΔTVtreatment% = 29.07% ± 10.01% and ΔTVcontrol% = 177.06% ± 63.00%, P = 0.008). The difference in ΔTV% between the treatment and the control groups was not significant at days 1 and 3 after a short duration of treatment. Increases in ADC in the treatment group (ΔADC%treatment, median, 30.10% ± 18.32%, 36.11% ± 21.82%, 45.22% ± 24.36%) were significantly higher compared with the control group (ΔADC%control, median, 4.98% ± 3.39%, 6.26% ± 3.08%, 9.24% ± 6.33%) at days 3, 5 and 7 (P = 0.008, P = 0.016, P = 0.008, respectively). Increases in D in the treatment group (ΔD%treatment, median 17.12% ± 8.20%, 24.16% ± 16.87%, 38.54% ± 19.36%) were higher than those in the control group (ΔD%control, median -0.13% ± 4.23%, 5.89% ± 4.56%, 5.54% ± 4.44%) at days 1, 3, and 5 (P = 0.032, P = 0.008, P = 0.016, respectively). Relative changes in f were significantly lower in the treatment group compared with the control group at days 1, 3, 5 and 7 follow-up (median, -34.13% ± 16.61% vs 1.68% ± 3.40%, P = 0.016; -50.64% ± 6.82% vs 3.01% ± 6.50%, P = 0.008; -49.93% ± 6.05% vs 0.97% ± 4.38%, P = 0.008, and -46.22% ± 7.75% vs 8.14% ± 6.75%, P = 0.008, respectively). D* in the treatment group decreased significantly compared to those in the control group at all time points (median, -32.10% ± 12.22% vs 1.85% ± 5.54%, P = 0.008; -44.14% ± 14.83% vs 2.29% ± 10.38%, P = 0.008; -59.06% ± 19.10% vs 3.86% ± 5.10%, P = 0.008 and -47.20% ± 20.48% vs 7.13% ± 9.88%, P = 0.016, respectively). Furthermore, histopathologic findings showed positive correlations with ADC and D and tumor necrosis (r s = 0.720, P < 0.001; r s = 0.522, P = 0.007, respectively). The cellular apoptosis of the tumor also showed positive correlations with ADC and D (r s = 0.626, P = 0.001; r s = 0.542, P = 0.005, respectively). Perfusion-related parameters (f and D(*)) were positively correlated to MVD (r s = 0.618, P = 0.001; r s = 0.538, P = 0.006, respectively), and negatively correlated to cellular apoptosis of the tumor (r s = -0.550, P = 0.004; r s = -0.692, P < 0.001, respectively).. IVIM-DWI is potentially useful for predicting the early efficacy of chemotherapy in a human gastric cancer mouse model.

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Fluorouracil; Humans; Image Processing, Computer-Assisted; In Situ Nick-End Labeling; Leucovorin; Mice; Mice, Nude; Microvessels; Necrosis; Neoplasm Transplantation; Stomach Neoplasms; Transplantation, Heterologous; Xenograft Model Antitumor Assays

Tumor hypoxia activates hypoxia-inducible factors (Hifs), which induce a range of malignant changes including vascular abnormalities. Here, we determine whether inhibition of the hypoxic tumor response through myo-inositol trispyrophosphate (ITPP), a compound with antihypoxic properties, is able to cause prolonged vascular normalization that can be exploited to improve standard-of-care treatment.. We tested ITPP on two syngeneic orthotopic mouse models of lethal colorectal cancer liver metastasis. Tumors were monitored by MRI and analyzed for the hypoxic response and their malignant potential. A Hif activator and in vitro assays were used to define the working mode of ITPP. Hypoxic response and vasculature were re-evaluated 4 weeks after treatment. Finally, we determined survival following ITPP monotherapy, FOLFOX monotherapy, FOLFOX plus Vegf antibody, and FOLFOX plus ITPP, both overlapping and sequential.. ITPP reduced tumor load, efficiently inhibited the hypoxic response, and improved survival. These effects were lost when mice were pretreated with a Hif activator. Its immediate effects on the hypoxic response, including an apparent normalization of tumor vasculature, persisted for at least 4 weeks after treatment cessation. Compared with FOLFOX alone, Vegf antibody combined with FOLFOX prolonged survival by <30%, whereas ITPP combined with FOLFOX extended survival by >140%, regardless of whether FOLFOX was given in overlap or after ITPP exposure.. Our findings reveal a truly antihypoxic mechanism for ITPP and demonstrate the capacity of this nontoxic compound to potentiate the efficacy of existing anticancer treatment in a way amenable to clinical translation. Clin Cancer Res; 22(23); 5887-97. ©2016 AACR.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line; Colonic Neoplasms; Disease Models, Animal; Fluorouracil; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Inositol Phosphates; Leucovorin; Liver; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Organoplatinum Compounds; Oxygen; Tumor Burden; Vascular Endothelial Growth Factor A

Copy number variations (CNVs) are thought to act as an important genetic mechanism underlying phenotypic heterogeneity. Impaired folate metabolism can result in neural tube defects (NTDs). However, the precise nature of the relationship between low folate status and NTDs remains unclear. Using an array-comparative genomic hybridization (aCGH) assay, we investigated whether CNVs could be detected in the NTD embryonic neural tissues of methotrexate (MTX)-induced folate dysmetabolism pregnant C57BL/6 mice and confirmed the findings with quantitative real-time PCR (qPCR). The CNVs were then comprehensively investigated using bioinformatics methods to prioritize candidate genes. We measured dihydrofolate reductase (DHFR) activity and concentrations of folate and relevant metabolites in maternal serum using enzymologic method and liquid chromatography/tandem mass spectrometry (LC/MS/MS). Three high confidence CNVs on XqA1.1, XqA1.1-qA2, and XqE3 were found in the NTD embryonic neural tissues. Twelve putative genes and three microRNAs were identified as potential susceptibility candidates in MTX-induced NTDs and possible roles in NTD pathogenesis. DHFR activity and 5-methyltetrahydrofolate (5-MeTHF), 5-formyltetrahydrofolate (5-FoTHF), and S-adenosylmethionine (SAM) concentrations of maternal serum decreased significantly after MTX injection. These findings suggest that CNVs caused by defects in folate metabolism lead to NTD, and further support the hypothesis that folate dysmetabolism is a direct cause for CNVs in MTX-induced NTDs.

Topics: Animals; Chromatography, Liquid; Comparative Genomic Hybridization; Disease Models, Animal; DNA Copy Number Variations; Folic Acid; Gene Expression Profiling; Genetic Predisposition to Disease; Leucovorin; Methotrexate; Mice, Inbred C57BL; MicroRNAs; Neural Tube Defects; Real-Time Polymerase Chain Reaction; S-Adenosylmethionine; Tandem Mass Spectrometry; Tetrahydrofolate Dehydrogenase; Tetrahydrofolates

Sinusoidal obstruction syndrome (SOS) following oxaliplatin based chemotherapy can have a significant impact on post-operative outcome following resection of colorectal liver metastases. To date no relevant experimental models of oxaliplatin induced SOS have been described. The aim of this project was to establish a rodent model which could be utilised to investigate mechanisms underlying SOS to aid the development of therapeutic strategies.. C57Bl/6 mice, maintained on a purified diet, were treated with intra-peritoneal FOLFOX (n=10), or vehicle (n=10), weekly for five weeks and culled one week following final treatment. Sections of the liver and spleen were fixed in formalin and paraffin embedded for histological analysis. The role of oxidative stress on experimental-induced SOS was determined by dietary supplementation with butylated hydroxyanisole and N-acetylcysteine.. FOLFOX treatment was associated with the development of sinusoidal dilatation and hepatocyte atrophy on H&E stained sections of the liver in keeping with SOS. Immunohistochemistry for p21 demonstrated the presence of replicative senescence within the sinusoidal endothelium. FOLFOX induced endothelial damage leads to a pro-thrombotic state within the liver associated with upregulation of PAI-1 (p<0.001), vWF (p<0.01) and Factor X (p<0.001), which may contribute to the propagation of liver injury. Dietary supplementation with the antioxidant BHA prevented the development of significant SOS.. We have developed the first reproducible model of chemotherapy induced SOS that reflects the pathogenesis of this disease in patients. It appears that the use of antioxidants alongside oxaliplatin based chemotherapy may be of value in preventing the development of SOS in patients with colorectal liver metastases.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Cell Cycle; Colorectal Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; Cytokines; Disease Models, Animal; Fluorouracil; Hepatic Veno-Occlusive Disease; Humans; Inflammation Mediators; Leucovorin; Liver Cirrhosis; Liver Neoplasms; Mice; Mice, Inbred C57BL; Neovascularization, Pathologic; Organoplatinum Compounds; Oxaliplatin; Oxidative Stress; Serpin E2; Thrombosis

Here we bioengineered a metastatic pancreatic tumor model with homogenous human CD133(+)CXCR4(+) cancer stem cells (CSC) and a polyglyconate/gelatin electrospun scaffold. The scaffold sported a highly porous microstructure with the majority of fibers possessing a diameter between 500μm and 1500μm. The scaffold supported the growth of tumor cells without provoking apoptosis. The homogeneous CD133(+)CXCR4(+) CSC was transplanted with the scaffold into the pancreas of nude mice to establish a metastatic pancreatic tumor. After 8 weeks, the tumor volume and weight in the scaffold model were 40.52% and 51.49% greater than the traditional model, respectively. The scaffold also increased the incidence of tumor formation and readily induced a hepatic metastasis. In this model we found that FOLFIRINOX possessed a superior capability of preventing the hepatic metastasis of pancreatic tumor cells than gemcitabine. A mechanistic study attributed this superiority to the fact that FOLFIRINOX could induce a greater apoptosis of CD133(+)CXCR4(+) CSC, thus depriving the driving force of hepatic metastasis. This metastatic tumor model showed an increased incidence of tumor formation, an accelerated tumorigenesis and a significant hepatic metastasis, therefore offering scientists a proven platform to study chemotherapeutic drugs.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bioengineering; Camptothecin; Cell Line, Tumor; Deoxycytidine; Disease Models, Animal; Female; Fluorouracil; Gemcitabine; Humans; Leucovorin; Liver Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Metastasis; Organoplatinum Compounds; Pancreatic Neoplasms; Tissue Scaffolds; Xenograft Model Antitumor Assays

Dengue virus has emerged as a global health threat to over one-third of humankind. As a positive-strand RNA virus, dengue virus relies on the host cell metabolism for its translation, replication, and egress. Therefore, a better understanding of the host cell metabolic pathways required for dengue virus infection offers the opportunity to develop new approaches for therapeutic intervention. In a recently described screen of known drugs and bioactive molecules, we observed that methotrexate and floxuridine inhibited dengue virus infections at low micromolar concentrations. Here, we demonstrate that all serotypes of dengue virus, as well as West Nile virus, are highly sensitive to both methotrexate and floxuridine, whereas other RNA viruses (Sindbis virus and vesicular stomatitis virus) are not. Interestingly, flavivirus replication was restored by folinic acid, a thymidine precursor, in the presence of methotrexate and by thymidine in the presence of floxuridine, suggesting an unexpected role for thymidine in flavivirus replication. Since thymidine is not incorporated into RNA genomes, it is likely that increased thymidine production is indirectly involved in flavivirus replication. A possible mechanism is suggested by the finding that p53 inhibition restored dengue virus replication in the presence of floxuridine, consistent with thymidine-less stress triggering p53-mediated antiflavivirus effects in infected cells. Our data reveal thymidine synthesis pathways as new and unexpected therapeutic targets for antiflaviviral drug development.

Topics: Animals; Antiviral Agents; Cell Line; Chlorocebus aethiops; Dengue Virus; Disease Models, Animal; DNA Viruses; Flavivirus; Flavivirus Infections; Floxuridine; HEK293 Cells; HeLa Cells; Humans; Leucovorin; Methotrexate; Mice; Mice, 129 Strain; Mice, Inbred C57BL; RNA Viruses; Thymidine; Tumor Suppressor Protein p53; Vero Cells; Virus Replication; West Nile virus

Advanced and recurrent diseases are the major causes of death in colon cancer. No standard preclinical model addresses advanced disease and spontaneous metastasis after orthotopic tumour growth. In this study, the authors report the establishment of such standardised orthotopic mouse models of colon cancer and their use in evaluating metronomic topotecan alone or in combination with standard chemotherapy.. Human colon cancer cell lines, transfected with human chorionic gonadotropin and luciferase, were injected orthotopically into the caecal wall of severe combined immunodeficient mice, intrasplenically or subcutaneously. For adjuvant therapy, caecal resections were performed 3-5 weeks after tumour cell injection. Chemotherapy drugs tested included uracil/tegafur, folinic acid, oxaliplatin, topotecan, pazopanib and various combinations.. Subcutaneous tumours showed exaggerated sensitivity to treatment by delayed tumour growth (p=0.002) and increased survival (p=0.0064), but no metastatic spread. Intrasplenic cell injection resulted in rapid and extensive but artefactual metastasis without treatment effect. Intracaecal cell injection with tumour take rates of 87.5-100% showed spontaneous metastases at clinically relevant rates. Metronomic topotecan significantly polonged survival and reduced metastasis. In the adjuvant setting, metronomic maintenance therapy (after FOLFOX-like induction) prolonged survival compared with vehicle controls (p=0.0003), control followed by topotecan (p=0.0161) or FOLFOX-like therapy (p=0.0003).. The refined orthotopic implantation technique proved to be a clinically relevant model for metastasis and therapy studies. Furthermore, metronomic therapy with oral topotecan may be promising to consider for clinical trials of metastatic colon cancer and long-term adjuvant maintenance therapy of colon cancer.

Topics: Administration, Metronomic; Administration, Oral; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Chemotherapy, Adjuvant; Colonic Neoplasms; Disease Models, Animal; Female; Fluorouracil; HT29 Cells; Humans; Immunohistochemistry; Injections; Leucovorin; Liver Neoplasms; Mice; Mice, SCID; Organoplatinum Compounds; Survival Rate; Topotecan

Mutations in the DNA mismatch repair (MMR) gene MSH2 cause Lynch syndromes I and II and sporadic colorectal cancers. Msh2(null) mice predominantly develop lymphoma and do not accurately recapitulate the colorectal cancer phenotype.. We generated and examined mice with a conditional Msh2 disruption (Msh2(LoxP)), permitting tissue-specific gene inactivation. ECMsh2(LoxP/LoxP) mice carried an EIIa-Cre transgene, and VCMsh2(LoxP/LoxP) mice carried a Villin-Cre transgene. We combined the VCMsh2(LoxP) allele with either Msh2(Delta7null) (VCMsh2(LoxP/null)) or Msh2(G674D) mutations (VCMsh2(LoxP/G674D)) to create allelic phase mutants. These mice were given cisplatin or 5-fluorouracil/leucovorin and oxaliplatin (FOLFOX), and their tumors were measured by magnetic resonance imaging.. Embryonic fibroblasts from ECMsh2(LoxP/LoxP) mice do not express MSH2 and are MMR deficient. Reverse transcription, polymerase chain reaction, and immunohistochemistry from VCMsh2(LoxP/LoxP) mice demonstrated specific loss of Msh2 messenger RNA and protein from epithelial cells of the intestinal tract. Microsatellite instability was observed in all VCMsh2 strains and limited to the intestinal mucosa. Resulting adenomas and adenocarcinomas had somatic truncation mutations to the adenomatous polyposis coli (Apc) gene. VCMsh2(LoxP/LoxP) mice did not develop lymphoma. Comparison of allelic phase tumors revealed significant differences in multiplicity and size. When treated with cisplatin or FOLFOX, tumor size was reduced in VCMsh2(LoxP/G674D) but not VCMsh2(LoxP/null) tumors. The apoptotic response to FOLFOX was partially sustained in the intestinal mucosa of VCMsh2(LoxP/G674D) animals.. Msh2(LoxP/LoxP) mice in combination with appropriate Cre recombinase transgenes have excellent potential for preclinical modeling of Lynch syndrome, MMR-deficient tumors of other tissue types, and use in drug development.

Topics: Adenocarcinoma; Adenoma; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cisplatin; Colorectal Neoplasms, Hereditary Nonpolyposis; Disease Models, Animal; Drug Resistance, Neoplasm; Fluorouracil; Gene Expression Regulation, Neoplastic; Gene Silencing; Genes, APC; Genotype; Immunohistochemistry; Integrases; Intestinal Neoplasms; Leucovorin; Magnetic Resonance Imaging; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins; Microsatellite Instability; Mutation; MutS Homolog 2 Protein; Organoplatinum Compounds; Phenotype; Reverse Transcriptase Polymerase Chain Reaction; Time Factors; Tumor Burden

The aim of this study was to determine the antimetastatic efficacy of the combination of 5-fluorouracil (5-FU), leucovorin (LV), and irinotecan (CPT-11) (FOLFIRI) in an orthotopic nude mouse model of GFP-HCT-116 human colon cancer-expressing green fluorescent protein (GFP). The mice were randomly divided into four groups: Group 1: saline control; Group 2: 30 mg/kg 5-FU + 90 mg/kg LV; Group 3: 5-FU + LV + 16 mg/kg CPT-11 (FOLFIRI); and Group 4: 5-FU + LV + 24 mg/kg CPT-11. 5-FU and LV were administered on days 11, 16 and 21, and CPT-11 on days 12, 18 and 22. Survival in Groups 3 and 4 was significantly longer than that in Groups 1 and 2, although no dose-dependency on CPT-11 was observed. Analysis of the primary and metastatic tumors by GFP imaging, as well as that of oncogene expression in mesentery lymph nodes, demonstrated that tumor growth and metastasis were significantly inhibited or even prevented by FOLFIRI. Pathological evaluation also demonstrated that metastasis was also inhibited by FOLFIRI. The results of the present study suggest FOLFIRI prolongs survival by inhibiting metastasis.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Cell Line, Tumor; Colonic Neoplasms; Disease Models, Animal; Disease Progression; Fluorouracil; Green Fluorescent Proteins; Humans; Leucovorin; Lymphatic Metastasis; Mice; Mice, Nude; Survival Rate; Treatment Outcome; Whole Body Imaging; Xenograft Model Antitumor Assays

The very early chemotherapeutic effects of the FOLFOX (fluorouracil, folinic acid, oxaliplatin) protocol were assessed in mice implanted with a human colorectal cell line. The aim of this study was to identify changes in gene expression patterns and to detect combinations of PET parameters that may be helpful in identifying treated tumours early after chemotherapy using dynamic PET studies.. A human colorectal cell line (HCT 116) was used in nude mice. Dynamic PET studies were performed in untreated (n = 13) and treated (n = 12) animals. The data were assessed using compartmental and noncompartmental analysis. The removed tumour specimens were assessed by gene array analysis to obtain quantitative information on gene expression.. One chemotherapeutic treatment using the FOLFOX protocol resulted in an upregulation of 2,078 gene probes by more than 25%, while 2,254 probes were downregulated following treatment. The gene array data demonstrated primarily an enhancement of genes related to apoptosis. In particular, the apoptosis antigen 1 (APO-1), p21 and the G protein-coupled receptor 87 (G-87) were 2.6- to 3.3-fold upregulated as compared to the expression in untreated animals. There was a 100% separation of untreated and treated animals on the basis of these three genes. The SUV and the FDG kinetic parameters obtained by compartmental and noncompartmental fitting were not significantly different when individual parameters were compared between groups. However, classification analysis of the combination of the PET parameters VB, K1, k3, and influx revealed an overall accuracy of 84%. We were able to identify 91.7% (11/12) of the treated animals and 76.9% (10/13) of the untreated animals correctly using the classification analysis of PET data.. Even one chemotherapeutic treatment using FOLFOX has an impact on gene expression and significantly modulates FDG kinetics. Quantitative assessment of the tracer kinetics and the application of classification analysis to the data are promising tools to identify those tumours that demonstrate a chemotherapeutic effect very early following treatment.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Colorectal Neoplasms; Disease Models, Animal; Fluorodeoxyglucose F18; Fluorouracil; Gene Expression Regulation, Neoplastic; Humans; Kinetics; Leucovorin; Mice; Mice, Nude; Neoplasm Transplantation; Organoplatinum Compounds; Positron-Emission Tomography

Fetal-onset hydrocephalus (HC), which affects between 1:500 and 1:5000 live human births, results from unequal production and drainage of cerebrospinal fluid (CSF) and is associated with abnormal development of the cerebral cortex leading to severe neurological deficits. We previously found that in the hydrocephalic Texas rat, the CSF of affected fetuses induced a cell cycle arrest in neural progenitor cells. Here, we show that alterations in folate metabolism in the CSF of the developing cerebrum are likely responsible for this effect. We identified 3 folate enzymes in the CSF and demonstrate that low levels of one of these, 10-formyltetrahydrofolate dehydrogenase, are associated with HC in the hydrocephalic Texas rat. Therefore, we tested whether supplementation with specific folate species would improve developmental outcome. After daily administration of a combination of tetrahydrofolic and 5-formyltetrahydrofolic acids to pregnant dams, there was a significant reduction in the incidence of HC and improved brain development. By contrast, supplementation with folic acid increased the incidence of congenital HC in this model. These results indicate the complexities of folate metabolism in the developing brain and suggest that folate imbalance leading to HC in the hydrocephalic Texas rat fetuses can be treated with maternal folate supplementation using specific folate metabolites and combinations thereof.

Topics: Age Factors; Animals; Bromodeoxyuridine; Cell Movement; Cell Proliferation; Cells, Cultured; Cerebral Cortex; Cerebrospinal Fluid; Chi-Square Distribution; Disease Models, Animal; Drug Combinations; Embryo, Mammalian; Female; Folic Acid; Hydrocephalus; Leucovorin; Maternal-Fetal Exchange; Pregnancy; Rats; Rats, Mutant Strains; Rats, Sprague-Dawley; Stem Cells; Tetrahydrofolates; Vitamin B Complex

Toxoplasma gondii is a widely distributed obligatory intracellular parasite that causes severe disease to the fetus when transmitted during pregnancy. Drugs used to avoid congenital transmission have shown side effects, and their efficacy is controversial. The most widely used treatment for acute toxoplasmosis during pregnancy is pyrimethamine plus sulfadiazine, which has several side effects. In this work, we tested the efficacy of azithromycin in reducing congenital transmission of T. gondii in the large vesper mouse, Calomys callosus, a rodent. Females of C callosus were inoculated perorally with 20 cysts of ME49 strain of T. gondii on the day of fertilization, and fetuses were collected from the 15th to the 19th day of gestation. Azithromycin (300 mg/kg), in association with pyrimethamine (100 or 50 mg/kg) plus sulfadiazine (100 or 75 mg/kg) and folinic acid (15 mg/kg) (SPAf), or vehicle, were administered orally on different days after infection. Brain and ocular tissues were removed and processed for immunohistochemistry using a polyclonal antibody against T. gondii, or were processed for parasite DNA quantification. Toxoplasma gondii was detected in the brains of all females and in fetuses' eyes of C. callosus treated with SPAf. On the other hand, in females treated with azithromycin, there was a reduction of T. gondii in the brains of mothers, and no parasites were detected in eyes of fetuses, indicating that azithromycin may represent an alternative treatment for toxoplasmosis during pregnancy.

Topics: Animals; Anti-Infective Agents; Antiprotozoal Agents; Azithromycin; Brain; Disease Models, Animal; DNA, Protozoan; Drug Therapy, Combination; Eye; Female; Fetus; Immunohistochemistry; Infectious Disease Transmission, Vertical; Leucovorin; Male; Polymerase Chain Reaction; Pregnancy; Pregnancy Complications, Parasitic; Pyrimethamine; Sigmodontinae; Sulfadiazine; Toxoplasma; Toxoplasmosis, Ocular; Vitamin B Complex

We evaluated the therapeutic effect of TS-1, a novel oral fluoropyrimidine, in combination with leucovorin with in vivo experiments using a murine tumor xenograft model fed a low folate diet. The reduced folate levels in the tumors of mice fed a low folate diet were significantly lower than those in the tumors of mice fed a normal diet. In addition, the basal reduced folate levels in the tumors of mice fed a low folate diet were comparable to those in human colorectal cancer tissues. Furthermore, when leucovorin was orally administered, the reduced folate levels in the tumors of mice fed a low folate diet were more than two-fold higher than those of mice fed the normal diet. The leucovorin-induced potentiation of TS-1 antitumor activity was obviously higher in COL-1 tumor-bearing mice fed a low folate diet than in mice fed a normal diet. The remarkable increase in reduced folate levels following the administration of leucovorin contributed to the leucovorin-induced potentiation of TS-1 antitumor activity in this low-folate-diet animal model. These results suggest that rodent models fed a low folate diet are suitable for in vivo evaluation of reduced folate drugs like leucovorin. In this model, the combination of leucovorin with TS-1 resulted in a higher antitumor efficacy than TS-1 alone or the combination of UFT and leucovorin, suggesting that TS-1 and leucovorin combination therapy may be an effective regimen for patients with colorectal cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Colorectal Neoplasms; Diet; Disease Models, Animal; Drug Combinations; Drug Evaluation; Folic Acid; Humans; Leucovorin; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Oxonic Acid; Tegafur

We evaluated the antitumor effect of combined therapy with tegafur/uracil (UFT) plus leucovorin (LV) (UFT/LV) and protein-bound polysaccharide, PSK, in three mouse models of transplantable tumors. UFT/LV showed antitumor effect against Meth A sarcoma, and the antitumor effect was enhanced when PSK given concomitantly. UFT/LV showed antitumor effect to Lewis lung carcinoma and PSK alone also showed antitumor effect at high dose, but a combination of UFT/LV and PSK resulted in no enhanced antitumor effect. Colon 26 carcinoma was weakly responsive to UFT/LV, and no enhancement of antitumor effect was found even PSK was used in combination. In conclusion, while the effect of PSK varies depending on tumor, combined use of UFT/LV and PSK may be expected to augment the antitumor effect.

Topics: Animals; Antineoplastic Agents; Carcinoma, Lewis Lung; Colonic Neoplasms; Disease Models, Animal; Drug Therapy, Combination; Female; Leucovorin; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Proteoglycans; Sarcoma; Tegafur; Uracil; Xenograft Model Antitumor Assays

Human colon cancer cells were implanted s.c. in nude mice. After 6 days, the mice were divided into four groups, 10 in each. During the first 5 days, the first and second groups were injected i.p. with leucovorin (LV)/5-fluorouracil (FU), and the third and fourth groups with sterile saline solution. During the subsequent 14 days, groups 1 and 4 received continuous i.p. infusion with sterile saline solution, while groups 2 and 3 received octreotide, galanin and serotonin via an implanted osmotic pump. Tumour volumes diminished significantly in mice treated with both LV/FU and LV/FU-triple therapy, as compared with controls. Both volume and weight of the tumours in mice given LV/FU-triple therapy were less than in those received LV/FU. The volume and weight of the tumours in animals treated with triple therapy was reduced as compared with controls, though not statistically significantly. The proliferation index, and the number of tumour blood vessels were both reduced, while the apoptotic index was increased in the mice treated with both LV/FU-triple therapy, and with triple therapy only as compared with LV/FU-treated mice. The present study has shown that the anti-tumour efficacy and therapeutic efficacy of triple therapy with octreotide, galanin and serotonin is equivalent to LV/FU and that sequential treatment with both could be beneficial.

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Division; Colonic Neoplasms; Disease Models, Animal; Female; Fluorouracil; Galanin; Humans; Leucovorin; Mice; Mice, Inbred C57BL; Mice, Nude; Neovascularization, Pathologic; Octreotide; Serotonin; Transplantation, Heterologous

Bent tail is a mouse model for X-linked neural tube defects (NTDs) that is characterized by the presence of exencephaly, a delayed posterior neuropore closure, and a tail phenotype. In addition, Bent tail shows laterality defects and increased prenatal mortality. The congenital malformations of this mouse are caused by a submicroscopic deletion that completely encompasses the gene coding for the zinc finger transcription factor Zic3. In this study we investigated the sensitivity of the phenotype of Bent tail to the nutrients folinic acid, myo-inositol, and zinc. These nutrients are thought to be involved in the etiology of NTDs, in combination with a genetic predisposition.. The most penetrant phenotype of the Bent tail mouse, the tail malformation, was used as a marker for the nutrient sensitivity of the neural phenotype. The size of the litters and the survival of the offspring, subdivided according to genotype, were analyzed as markers for the nutrient sensitivity of other phenotypic features of Bent tail.. In confirmation of earlier studies, we observed the prenatal loss of a number of homozygous females and hemizygous males, as well as the effect of genotype on the tail phenotype of Bent tail. However, periconceptional supplementation of the maternal diet with folinic acid, myo-inositol, or zinc produced no significant effects on either the tail phenotype of the offspring or the size and genotypic composition of the litters.. Bent tail appears to be a folinic acid-, myo-inositol-, and zinc-insensitive mouse model for NTDs.

Topics: Animals; Diet; Disease Models, Animal; DNA; Embryo Loss; Female; Genotype; Inositol; Leucovorin; Litter Size; Male; Mice; Mice, Mutant Strains; Morphogenesis; Neural Tube Defects; Pregnancy; Tail; Zinc

Folic acid (FA) supplementation reduces neural tube defects (NTDs) by 70%. However, the cause of most NTDs cannot be attributed to folate deficiency, to mutations of genes that encode folate pathway enzymes, and folate receptors (FRs) that mediate cellular folate uptake. Mouse embryos nullizygous for the ortholog of the FRalpha gene have lethal congenital abnormalities that are preventable by administration of folinic acid to the dams. To determine whether antibodies to FRs are similarly teratogenic, we studied a rat model.. Immunohistochemistry with an antiserum to rat FRs was used to identify the receptors on reproductive tissues and embryos. Gestation day (GD) 8 rats received intraperitoneal injections of antiserum to the FRs, and their embryos were examined 2-9 days later. Some rats received pharmacologic doses of folinic acid or dexamethasone before the antiserum was administered.. The FRs are present on oocytes, the oviduct, and uterine epithelial cells, and in the embryo at all stages examined between GD4 and GD15. The antiserum has a dose-related effect on embryo viability and organogenesis. Folinic acid prevented teratogenicity resulting from smaller doses of antiserum, but not that caused by larger doses. Resorption of embryos with the larger doses of the antiserum was prevented by dexamethasone.. FRs are expressed on oocytes, epithelial cells of reproductive organs, and embryonic and extraembryonic tissues. Antiserum to FRs administered to pregnant rats causes embryonic damage. Embryo lethality with smaller doses of antiserum is preventable by administration of folinic acid, while larger doses cause embryo damage by immune-mediated cell lysis, which can be prevented by dexamethasone.

Topics: Animals; Antibodies, Blocking; Antibody Specificity; Autoantibodies; Carrier Proteins; Dexamethasone; Disease Models, Animal; Dose-Response Relationship, Immunologic; Drug Therapy, Combination; Embryonic and Fetal Development; Female; Folate Receptors, GPI-Anchored; Folic Acid; Injections, Intraperitoneal; Leucovorin; Pregnancy; Rats; Rats, Sprague-Dawley; Receptors, Cell Surface

The biochemical basis for modulation of fluorouracil (FU) activity by leucovorin is elevation of the metabolite methylenetetrahydrofolate, which stabilizes the inhibitory ternary complex formed between thymidylate synthase and the active metabolite of FU, 5-fluorodeoxyuridylate. Folic acid, because it can also potentially be metabolized to methylenetetrahydrofolate, was evaluated for its ability to potentiate FU antitumor activity in a dietary folic acid restricted murine model. The plasma pharmacokinetics and tissue distribution of folic acid and all stable metabolites thereof were determined in the model to establish administration schedules. FU was administered to mice implanted subcutaneously with a mammary adenocarcinoma 4 hr after folic acid administration, when the metabolites, methylenetetrahydrofolate and tetrahydrofolate, were elevated maximally in both plasma and tumor tissue. While FU alone suppressed growth 25%, folic acid in combination with FU increased growth suppression to over 70%. These results indicate that folic acid is a potent modulator of FU activity and could be considered as an alternative to leucovorin in the clinical setting.

Topics: Animals; Antidotes; Antimetabolites, Antineoplastic; Diet; Disease Models, Animal; Drug Synergism; Fluorouracil; Folic Acid; Folic Acid Deficiency; Leucovorin; Mice; Mice, Inbred C3H; Neoplasms, Experimental

The effects of the two diastereoisomers of 5-formyltetrahydrofolate on tumour growth, thymidylate synthase (TS, EC 2.1.1.45) levels, and potentiation of 5-fluorouracil cytotoxicity were studied in an in vivo rat colon carcinoma model, transplanted to liver. The animals were randomized into eight groups, treated with daily i.v. tail vein injections of racemic (d,l)-5-formyltetrahydrofolate (5-CHO-FH4), 15 mg/kg, (1)-5-CHO-FH4 7.5 mg/kg, and (d)-5-CHO-FH4 7.5 mg/kg, 5-fluorouracil (FUra) 30 mg/kg, (d,l)-5-CHO-FH4 15 mg/kg+FUra 30 mg/kg, (l) 5-CHO-FH4 7.5 mg/kg+FUra 30 mg/kg, and (d)-5-CHO-FH4 7.5 mg/kg+FUra 30 mg/kg, and a sham-treated control group. The average tumour size of the groups was equal at the start of treatment. After six days' treatment the average tumour sizes were at laparotomy 3.3 +/- 1.0 g in the (d/l)-5-CHO-FH4 treated group, compared to 2.0 +/- 0.1 g in the FUra treated group and 7.1 +/- 3.1 g in the controls. Natural (l)-5-CHO-FH4 promoted tumour growth (average tumour weight 10.8 +/- 4.0 g), whereas the unnatural (d)-5-CHO-FH4 alone retarded it (average tumour weight 1.2 +/- 0.40 g). (l)-5-CHO-FH4 induced a significant increase in tumour tissue TS levels by [3H]FdUMP radioligand assay (27.5 +/- 8.4 pmol/g tumour tissue) compared to controls (16.8 +/- 6.1 pmol/g tumour tissue). Increases in 5,10-methylenetetrahydrofolate and tetrahydrofolate occurred with FUra alone, with a further statistically significant increase in both folates with the addition of (d)-5-CHO-FH4 to FUra.

Topics: Animals; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Cell Division; Colonic Neoplasms; Disease Models, Animal; Enzyme Inhibitors; Fluorouracil; Leucovorin; Liver Neoplasms, Experimental; Male; Neoplasm Transplantation; Random Allocation; Rats; Rats, Wistar; Stereoisomerism; Thymidylate Synthase

This study was designed to determine the effects of 5-fluorouracil and leucovorin on the healing of colonic anastomoses and assess the safety of conducting a colonic resection and anastomosis during and shortly after a course of this chemotherapy in a rat model.. Fifty-six male Wistar rats, weighing 200 to 250 gm, were divided into four groups, each consisting of 14 animals. Animals in Group I (control group) underwent colon resection and primary anastomosis. Animals in Group II received 10 mg/kg intravenous 5-fluorouracil and 10 mg/kg leucovorin once a week for four weeks and then underwent the same operation. Animals in Groups III and IV received the same drug dosage for six weeks and were operated at different intervals: Group III at one week and Group IV at two weeks after completion of chemotherapy. Within each group, one-half of the animals were sacrificed on the third postoperative day and one-half on the seventh postoperative day, and anastomotic bursting pressure measurements were performed.. At three and seven days, mean bursting pressure of the anastomoses were determined: 98 mmHg and 180.7 mmHg in Group I, 95 and 197.8 in Group II, 85.7 and 189.2 in Group III, and 98.6 and 179.2 in Group IV, respectively. There was no significant difference in bursting pressure between treated animals and controls by the third postoperative day or by the seventh day. The burst occurred at the anastomosis in all specimens tested on the third postoperative day and in the bowel wall adjacent to the anastomosis in all specimens tested on the seventh postoperative day.. This study demonstrates that the above regimen of chemotherapy has no effect on the healing of colonic anastomoses and that surgery can be performed safely during and shortly after this regimen of chemotherapy.

Topics: Anastomosis, Surgical; Animals; Colectomy; Colon; Disease Models, Animal; Fluorouracil; Injections, Intravenous; Leucovorin; Male; Pressure; Rats; Rats, Wistar; Rupture; Wound Healing

A study was performed in 110 rats to investigate the effect of an LD50 dose of MTX, rescued with leucovorin treatment in 24 hours, on the ability of surgical wounds to tolerate bacterial contamination. The results of this study would indicate that the optimal time to ensure normal wound healing would be an interval of 10 to 14 days following the administration of large doses of this drug. This information would suggest that the use of methotrexate as a preoperative adjuvant, and radiation therapy following the surgical removal of the tumor, might be a reasonable approach to the adjuvant treatment of head and neck cancer without increasing the risk of wound infections.

Topics: Animals; Disease Models, Animal; Head and Neck Neoplasms; Humans; Lethal Dose 50; Leucovorin; Leukocyte Count; Male; Methotrexate; Preoperative Care; Radiotherapy, High-Energy; Rats; Staphylococcal Infections; Surgical Wound Infection; Time Factors; Wound Healing

An analysis of dose and schedule dependence of calcium leucovorin rescue during high-dose methotrexate therapy of ascitic forms of l1210 leukemia and Sarcoma 180 is reported. Schedules with very delayed "low-dose" leucovorin rescue following lethal doses of methotrexate were highly effective in preventing toxicity and achieved a pronounced antitumor effect in both ascites tumor models. Best results were obtained on a schedule of methotrexate (400 mg/kg s.c.) followed 16 to 20 hr later by calcium leucovorin (12 mg/kg s.c.) given once every 2 hr for a total of 5 doses. Progressive increases in the calcium leucovorin dosage on any schedule reduced both toxicity and the antitumor effect of methotrexate in each model. Following a single course of therapy, essentially no toxicity was observed, and the antitumor effects were 2-fold (L1210 leukemia) and 4-fold (Sarcoma 180) greater than a single, maximally tolerated dose (24/kg s.c.) methotrexate alone. An increase in the methotrexate dosage to 800 mg/kg s.c. with or without an increase in calcium leucovorin dosages on the same schedule did not appreciably increase the antitumor effect observed. Two courses of high-dose methotrexate (400 mg/kg s.c.) with leucovorin rescue (24 mg/kg s.c. 16, 20, and 24 hr after drug) given with an 8-day interval between courses doubled the total antitumor effect in each model with no substantial increase in toxicity and gave long-term survivors with Sarcoma 180. The results, overall, are in close agreement with prior prediction for schedule and dose dependence made on the basis of related pharmacokinetic and biochemical studies in murine tumor models reported from this laboratory.

Topics: Animals; Calcium; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Female; Leucovorin; Leukemia L1210; Methotrexate; Mice; Mice, Inbred Strains; Sarcoma 180; Time Factors

Topics: Animals; Antibody Formation; Antilymphocyte Serum; Azathioprine; Cells, Cultured; Dactinomycin; Disease Models, Animal; Female; Hot Temperature; Immunity, Cellular; Immunosuppressive Agents; Kidney; Kidney Transplantation; Leucovorin; Male; Methotrexate; Methylprednisolone; Radiation Effects; Rats; Thoracic Duct; Transplantation Immunology