In human malignant keratinocytes, N-nitroso-N-methylurea (NMU; 5 μM) therapy promotes cellular NF-κB activity. I-κBα phosphorylation is also increased by N-nitroso-N-methylurea [5].

Tumor models can be created in animals by using N-nitroso-N-methylurea.

Absorption, Distribution and Excretion
The high chemical reactivity of NMU makes its degradation unlikely to involve enzymatic catalysis. NMU is a direct alkylating agent that can alkylate nucleic acids in vitro and in vivo. This alkylation has been detected in various tissues of multiple animals, including mice, rats, hamsters, and miniature pigs, including the brain, lungs, kidneys, liver, intestines, thymus, and spleen. All three hydrogen atoms in the NMU methyl group are retained in the methylated nucleosides formed after NMU alkylation of nucleic acids. Metabolism/Metabolites The cyanate ions produced by the degradation of NMU under physiological pH conditions can react with proteins via carbonylation. In vivo NMU generation was confirmed by methylation at the N7 position of guanine after administration of the precursor methylurea and sodium nitrite. (Unspecified species) Biological Half-Life NMU was undetectable in rat blood 15 minutes after intravenous injection of 100 mg/kg body weight of NMU.

Toxicity Summary
Identification and Uses: N-Nitrosaminoglycans (NMU) are solids. NMU was once widely used in the laboratory synthesis of diazomethanes, but has been replaced by other reagents. NMU has been studied as a chemotherapeutic agent for cancer treatment, used alone or in combination with cyclophosphamide. Small amounts of NMU have also been used to study its mutagenic effects on plants. Human Studies: Intravenous injection of 4 mg/kg body weight of NMU caused nausea and vomiting in patients. NMU can cause mutations in the human lymphoblastic cell line TK6. Repeated exposure to NMU has been reported to cause malignant transformation of adult prostate epithelial cells. Animal Studies: The main toxic effects of NMU in animals stem from its severe damage to hematopoietic, lymphatic, and other rapidly regenerating tissues. Acute NMU treatment has been shown to inhibit protein and nucleic acid synthesis in tissues. NMU can acutely induce photoreceptor degeneration, primarily rod-cell-based, in the monkey retina, but the photoreceptor function of both rod and cone cells is impaired. Intraperitoneal injection of NMU induced moderate systemic side effects and selective photoreceptor degeneration in mice. Intravitreal injection of NMU also induced photoreceptor degeneration; however, no systemic side effects were observed. In rabbits, intravitreal injection of 3 mg/kg body weight of NMU induced selective but uneven photoreceptor degeneration. In rats, forestomal cancer was observed after administration of 10 mg/kg body weight of NMU every 2 weeks or 20 mg/kg body weight of NMU every 4 weeks for 9 months. Malignant tumors of the brain (sarcoma, glioma) and malignant tumors of the peripheral nervous system (called neurosarcoma) were also observed. Two out of ten rats developed odontogenic tumors after a single gavage administration of 90 mg/kg body weight of NMU. Miniature pigs were treated with 10 mg/kg body weight of NMU every two weeks for 4.5 years. All nine animals that survived 50 months developed benign gastric tumors and some malignant tumors. Three monkey species—rhesus macaques (Macaca mulatta), cynomolgus monkeys (M. fascicularis), and African long-tailed macaques (Cercopithecus aethiops)—developed squamous cell carcinomas in their oropharynx and/or esophagus after oral administration of NMU. In 125 newborn mice, a single dermal application of 50-100 mg/kg body weight of NMU induced primary lymphocytic leukemia in approximately 50% of the tested animals. In rats, applying 1.75 mg (0.5%) of a 0.5% NMU solution three times a week for 30 weeks resulted in multiple squamous cell carcinomas and basal cell carcinomas in nine rats. The first tumor appeared at week 20. In 20 Syrian golden hamsters, applying 0.35 mg (0.5%) of a 0.5% NMU solution three times a week for 13 weeks resulted in squamous cell carcinomas in 18 hamsters, with the first tumor appearing at week 8. Neurological and renal tumors were observed in the offspring of rats treated with NMU in late pregnancy. Mammary tumors also appeared in treated female rats. Offspring of male mice treated with NMU also exhibited congenital defects. A mouse model of retinal degeneration has been established using NMU. In mice, treatment on day 11 of gestation resulted in the primary effect of digit agenesis. Treatment on day 12 particularly induced bilateral microdactylus deformities. The genetic activity of NMU has been demonstrated in bacteriophages, Escherichia coli, Salmonella typhimurium, Saccharomyces cerevisiae, Serratia marcescens, Hamsteria sinensis cells, and Drosophila melanogaster, inducing both forward and reverse mutations and gene conversion.

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Interactions
Rats were pretreated with N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea for several weeks. Subsequently, a single low-dose dose of radiolabeled dimethylnitrosamine was administered to assess the liver's ability to repair O6-methylguanine. ...Pretreatment with N-ethyl-N-nitrosourea for 2 weeks significantly enhanced the repair of O6-methylguanine, with similar effects to pretreatment with diethylnitrosamine, which served as a positive control. The same pretreatment regimen was highly effective for N-ethyl-N-nitrosourea but completely ineffective for N-methyl-N-nitrosourea. When the administration time of N-methyl-nitrosourea was extended from 2 weeks to 8 weeks, a small but statistically significant increase in O6-methylguanine repair was observed. ...There are two reasons for the low efficacy of N-methyl-nitrosourea. First, compared to dimethylnitrosamine, this compound induced a relatively low degree of hepatic DNA methylation. Second, the methylating agent induced the O6-ethylating agent less efficiently. ...The conclusion is that the ability of a substance to enhance the repair of O6-methylguanine in rat liver...reflects the substance's hepatic (co)carcinogenic potential.
Perinatal administration of nicotine significantly reduced tumors following transplacental induced NMU. In F1 generation rats, oral administration of NMU to mothers resulted in an overall tumor incidence of 85%, primarily in the nervous system. Regular injections of nicotine before or after birth reduced malignant tumors by 17% and 22%, respectively. …These findings suggest that nicotine can modulate the expression of chemically induced nervous system tumors in a favorable manner.
Application of MNU to fertilized oocytes of rice (Oryza sativa L.) increased the range of variations in aluminum tolerance in the M2 generation. For the M3 generation, this induced variation in the M2 generation was heritable; 50 variants showed varying degrees of tolerance to aluminum toxicity, some of which did not show growth inhibition even at 30 ppm aluminum concentrations. Tolerance to aluminum toxicity and longer root development were correlated.
Ellagic acid…inhibits the activity of the direct-acting mutagen N-methyl-N-nitrosourea in Salmonella Typhimurium TA100. Ellagic acid at concentrations of 0.10, 0.25, 0.50, and 1.0 mM inhibited the mutagenicity of N-methyl-N-nitrosourea (0.40 mM) by 3%, 13%, 45%, and 60%, respectively… The inhibitory effect of ellagic acid on the mutagenicity induced by N-methyl-N-nitrosourea is due to its specific inhibition of methylation at the guanine O6 site through the ellagic acid-double-stranded DNA affinity binding mechanism. For more complete data on interactions of N-nitrosourea (18 in total), please visit the HSDB record page.

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Non-human toxicity values
Oral LD50 in rats: 110 mg/kg body weight
Intravenous LD50 in rats: 110 mg/kg body weight
Subcutaneous LD50 in hamsters: 110 mg/kg body weight (bw)
LD50 in hamsters (subcutaneous injection): 50 mg/kg (bw)
For more complete non-human toxicity data for N-nitroso-N-methylurea (6 in total), please visit the HSDB records page.

[1]. N-nitrosomethylurea as mammary gland carcinogen in rats. J Natl Cancer Inst. 1975 Feb;54(2):401-14.

[2]. Review: Animal models of N-Methyl-N-nitrosourea-induced mammary cancer and retinal degeneration with special emphasis on therapeutic trials. In Vivo. 2011 Jan-Feb;25(1):11-22.

[3]. Effects of N-nitroso-N-methylurea on enzymatic ontogeny associated with teratogenesis. Teratology. 1968 May;1(2):179-91.

[4]. One-pot synthesis of α-haloketones employing a membrane-based semibatch diazomethane generator. Journal of Flow Chemistry volume 6, pages211-217(2016).

[5]. Moon KY. N-nitroso-N-methylurea and N-nitroso-N-ethylurea induce upregulation of cellular NF-kappa B activity through protein kinase C-dependent pathway in human malignant keratinocytes. Arch Pharm Res. 2010 Jan;33(1):133-9.

[6]. Palliative Role of Aqueous Ginger Extract on N-Nitroso-N-Methylurea-Induced Gastric Cancer. Nutr Cancer. 2020;72(1):157-169.

[7]. Effect of Crocin on Cell Cycle Regulators in N-Nitroso-N-Methylurea-Induced Breast Cancer in Rats. DNA Cell Biol. 2015 Nov;34(11):684-91.

According to an independent committee of scientific and health experts, N-nitroso-N-methylurea may be carcinogenic. N-nitroso-N-methylurea is a pale yellow crystal or a light yellow wet powder. (NTP, 1992) N-methyl-N-nitrosourea belongs to the N-nitrosourea class of compounds, a type of urea in which one nitrogen atom is replaced by a methyl group and a nitrosyl group. It is carcinogenic, mutagenic, teratogenic, and alkylating. N-nitroso-N-methylurea has been used in mutagenic and genetic studies and has been investigated as a chemotherapy drug for cancer. There is currently no commercial use for N-nitroso-N-methylurea. Acute (short-term) exposure to N-nitroso-N-methylurea in humans can cause dermatitis. There is currently no information on the chronic (long-term), reproductive, developmental, or carcinogenic effects of N-nitroso-N-methylurea in humans or animals. There are reports of tumors in the offspring of animals treated with N-nitroso-N-methylurea during pregnancy. Animal studies have shown that oral administration of N-nitroso-N-methylurea can lead to tumors in the brain, spinal cord, nerves, stomach, pancreas, and kidneys. The U.S. Environmental Protection Agency (EPA) has classified N-nitroso-N-methylurea as a Group B2 carcinogen, meaning it is likely carcinogenic to humans. Methylnitrosourea is a pale yellow crystalline nitrosourea that is sensitive to light and moisture and releases toxic nitrogen oxide fumes when heated. Methylnitrosourea is an alkylating agent primarily used in tumor-inducing research and has also been studied as a chemotherapy drug for cancer treatment. Exposure to methylnitrosourea can cause dermatitis. Methylnitrosourea is reasonably expected to be a human carcinogen. (NCI05)
A nitrosourea compound with alkylating, carcinogenic, and mutagenic properties.

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Mechanism of Action
The role of the oncogene ras in carcinogen-induced tumor transformation was studied. N-nitroso-N-methylurea and 7,12-dimethylbenzanthracene-induced rat mammary cancer showed mutations at codons 12 and 61 of the H-ras-1 gene, respectively. The mutation at codon 12 was a transition from guanine-guanine-adenine to guanine-adenine-adenine.

C₂H₅N₃O₂

103.08

103.038

684-93-5

12699

Off-white to light brown solid powder

1.5±0.1 g/cm3

164.3±23.0 °C at 760 mmHg

119-124°C

53.1±22.6 °C

2.0±0.3 mmHg at 25°C

1.545

-0.03

1

3

0

7

90.9

0

ZRKWMRDKSOPRRS-UHFFFAOYSA-N

InChI=1S/C2H5N3O2/c1-5(4-7)2(3)6/h1H3,(H2,3,6)

1-methyl-1-nitrosourea

NNitrosoNmethylurea; N Nitroso N methylurea

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: (1). This product requires protection from light (avoid light exposure) during transportation and storage.  (2). Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~250 mg/mL (~2425.30 mM)` H2O : ~50 mg/mL (~485.06 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (20.18 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (20.18 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (20.18 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 10 mg/mL (97.01 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication (<60°C).

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 (Please use freshly prepared in vivo formulations for optimal results.)