Highly immunogenic "tum-" (non-tumorigenic in normal syngeneic hosts) clonal variants can be selected from a variety of poorly immunogenic and highly tumorigenic mouse cell lines at very high frequencies (e.g., greater than 80%) after treatment in vitro with chemical mutagens such as ethyl methanesulfonate (EMS) or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). We herein demonstrate that the same...

Four types of phytoncide solution (A-Type, AB-Type, D-Type and G-Type) were evaluated as antimutagenic agents with suppressive effects on the SOS-inducing activity of the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (furylfuramide) using Salmonella typhimurium TA1535/pSK1002 umu test. The A-Type, AB-Type, D-Type and G-Type of phytoncide solution suppressed the SOS-inducing activity on fur...

Mesenchymal stem cells (MSCs) are a critical component of the tumor microenvironment. Upon distinct pathological stimulus, MSCs show phenotypic and functional changes. Gastric cancer is one of the leading causes of cancer‑related deaths worldwide. The roles and mechanisms of MSCs in gastric cancer have not been well characterized. In the present study, we investigated the roles of MSCs in the m...

There is considerable uncertainty of the potential biological effects of extremely low frequency magnetic fields (ELF-MF or EMF) because of mixed results in epidemiological and laboratory studies. In the present study, exponentially growing human-hamster hybrid A(L) cells were treated with a 100 microT alternating EMF powered at 60 Hz for either 24 h or 7 days. Exposure to EMF was conducted eit...

The phenomenon of alkylation tolerance has been observed in cells that are deficient in some component of the DNA mismatch repair (MMR) system. An alkylation-induced cell cycle arrest had been reported previously in one MMR-proficient cell line, whereas a MMR-defective clone derived from this line escapes from this arrest. We examined human cancer cell lines to determine if the cell cycle arres...

cytotoxicity of MNNG. Shown in Figure 1B is a schematic incorporating the DCD1related findings reported here and those from a previous report [2]. The MMR-dependent response to Sn1-type methylating agents most likely involves additional proteins besides those normally associated with MMR-dependent spellchecking (for a review, see [1]). Our study has uncovered one such protein, Dcd1, which modul...

The effect of calcium carbonate (CaCO3) on the initiation of gastroduodenal carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was examined under the conditions with and without sodium chloride. Male Wistar rats were given drinking water containing MNNG (100 mg/liter) and one of the following diets during the first 20 weeks ad libitum. Group 1 was given basal diet; group 2, d...

Programmed necrosis induced by DNA alkylating agents, such as MNNG, is a caspase-independent mode of cell death mediated by apoptosis-inducing factor (AIF). After poly(ADP-ribose) polymerase 1, calpain, and Bax activation, AIF moves from the mitochondria to the nucleus where it induces chromatinolysis and cell death. The mechanisms underlying the nuclear action of AIF are, however, largely unkn...

Alkylation chemotherapy has been a long-standing treatment protocol for human neoplasia. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a direct-acting monofunctional alkylator. Temozolomide is a clinical chemotherapeutic equivalent requiring metabolic breakdown to the alkylating agent. Both chemicals have similar mechanistic efficacy against DNA mismatch repair-proficient tumor cells that lack...