Mitomycin C (MC), a commonly used anticancer drug, induces DNA damage via DNA alkylation. Decarbamoyl mitomycin C (DMC), another mitomycin lacking the carbamate at C10, generates similar lesions as MC. Interstrand cross-links (ICLs) are believed to be the lesions primarily responsible for the cytotoxicity of MC and DMC. The major ICL generated by MC (α-ICL) has a trans stereochemistry at the guanine-drug linkage whereas the major ICL from DMC (β-ICL) has the opposite, cis, stereochemistry. In addition, DMC can provoke strong p53-independent cell death. Our hypothesis is that the stereochemistry of the major unique β-ICL generated by DMC is responsible for this p53-independent cell death signaling. p53 gene is inactively mutated in more than half of human cancers. p21WAF1/CIP1 known as a major effector of p53 is involved in p53-dependent and -independent control of cell proliferation and death. This study revealed the role of p21WAF1/CIP1 on MC and DMC triggered cell damage. MCF-7 (p53-proficient) and K562 (p53-deficient) cells were used. Cell cycle distributions were shifted to the G1/S phase in MCF-7 treated with MC and DMC, but were shifted to the S phase in K562. p21WAF1/CIP1 activation was observed in both cells treated with MC and DMC, and DMC triggered more significant activation. Knocking down p53 in MCF-7 did not attenuate MC and DMC induced p21WAF1/CIP1 activation. The α-ICL itself was enough to cause p21WAF1/CIP1 activation.

The aim of this study was to evaluate the outcomes of trabeculectomy with mitomycin C (MMC) in patients with Pseudoexfoliative Glaucoma (PXG) and compare the results with the outcomes of trabeculectomy without MMC in PXG and with MMC in Primary Open Angle Glaucoma (POAG). Ninety eyes (76 patients) submitted to trabeculectomy were included in a one-year retrospective study. Fifty-eight eyes with PXG were divided into group 1 (28 eyes) and group 2 (30 eyes), with and without MMC application respectively. Then, the group 1 results were compared with 32 eyes with POAG that performed trabeculectomy with MMC (group 3). Main outcome measures were intraocular pressure (IOP), number of IOP lowering medications, rate of bleb failure (encapsulation, flattening and/or vascularization) and the number of eyes submitted to surgical procedures after trabeculectomy (needling, 5-fluorouracil (5FU) or 2nd trabeculectomy). Results revealed that compared to trabeculectomy with MMC in POAG and trabeculectomy with MMC in PXG, trabeculectomy without MMC in PXG leads to higher IOP (preoperative mean ± standard deviation [SD] was 28.6 ± 5.4 mmHg in group 1, 32.2 ± 8.2 mmHg in group 2 and 26.1 ± 6.5 mmHg in group 3; and after one year was 13.9 ± 3.9 mmHg in group 1, 16.1 ± 5.9 mmHg in group 2 and 12.5 ± 4.0 mmHg in group 3); higher number of IOP lowering medications (preoperative mean ± SD was 3.1 ± 0.60 in group 1, 2.8 ± 0.81 in group 2 and 3.4 ± 0.76 in group 3; and after one year was 1.1 ± 1.1 in group 1, 1.1 ± 1.0 in group 2 and 0.33 ± 0.89 in group 3); higher prevalence of bleb failure (47% in group 1, 53% in group 2, and 18% in group 3); and increased participation in surgical procedures following trabeculectomy (47% in group 1, 57% in group 2, and 6% in group 3). We concluded that trabeculectomy without MMC in PXG had the worst surgical outcome. Thus, PXG appears to be a potential risk factor for filtration bleb failure. Therefore, it could be considered in surgical protocols of MMC application.

We studied the efficacy and safety of using topical mitomycin C (MMC) as an adjunct to glaucoma filtration surgery. Trabeculectomy was performed in 23 eyes of 19 patients with poor surgical prognosis. After the preparation of a scleral flap, 0.2 mg or 0.4 mg/ml MMC was applied to the exposed tissue for 5 minutes. The wound was then irrigated with 250ml of normal saline. The mean follow-up period was 7.8 months. Preoperative mean intraocular pressure (IOP) was 33.8mmHg, and the mean IOPs on 1, 3, 6, and 12 months after operation were 10.3, 12.5, 12.4 and 12.3mmHg, respectively. At postoperative 12 months, 74.7% achieved an IOP of less than or equal to 20mmHg without any antiglaucoma medication. There were early postoperative complications of aqueous leaking from conjunctival wounds in 3 eyes (13.0%), shallow anterior chamber in 2 eyes, and hyphema in one eye and one eye had long-term hypotony lasting more than 3 months. Although MMC is simple to use, it is a potent adjunct to glaucoma filtration surgery, more work should follow to determine the mechanism of action, indications, dosage and optimal exposure time of MMC.

Several adjuvant therapies to surgery have been used to modulate the healing process of vocal folds, including topic mitomycin (MTC).

Mitomycin treatment induces pulmonary toxicity, and alveolar epithelial cell senescence is crucial in the pathogenesis of the latter. However, the mechanism by which mitomycin induces alveolar epithelial cell senescence has yet to be elucidated. In this work, different doses (37.5-300 nM) of mitomycin induced the senescence of human alveolar type II-like epithelial cells and enhanced the phosphorylation of GSK3β (S9). The GSK3β (S9A) mutant reversed the senescence of mitomycin-treated alveolar epithelial cells. Pharmacological inhibition and gene deletion of Akt1, a kinase that regulates the phosphorylation of GSK3β (S9), suppressed mitomycin-induced alveolar epithelial cell senescence. The knockdown of p53, a downstream effector of GSK3β and an important regulator of cell senescence, repressed mitomycin-induced alveolar epithelial cell senescence. Treatment with baicalein weakened the phosphorylation of GSK3β (S9) and alleviated the senescence of alveolar epithelial cells brought about by mitomycin treatment. GSK3β (S9) phosphorylation appears to be the first signal involved in the mitomycin-induced senescence of alveolar epithelial cells and may present a potential target for attenuating mitomycin-induced pulmonary toxicity.

To evaluate the efficacy and safety of trabeculectomy (Trab) with mitomycin-C (MMC) versus Trab with implant.

To evaluate the relationship between bleb vascularity and surgical outcome one year after mitomycin C (MMC) augmented trabeculectomy.

Mitomycin C (MMC) repair factor A (mrfA) and factor B (mrfB), encode a conserved helicase and exonuclease that repair DNA damage in the soil-dwelling bacterium Bacillus subtilis. Here we have focused on the characterization of MrfB, a DEDDh exonuclease in the DnaQ superfamily. We solved the structure of the exonuclease core of MrfB to a resolution of 2.1 Å, in what appears to be an inactive state. In this conformation, a predicted α-helix containing the catalytic DEDDh residue Asp172 adopts a random coil, which moves Asp172 away from the active site and results in the occupancy of only one of the two catalytic Mg2+ ions. We propose that MrfB resides in this inactive state until it interacts with DNA to become activated. By comparing our structure to an AlphaFold prediction as well as other DnaQ-family structures, we located residues hypothesized to be important for exonuclease function. Using exonuclease assays we show that MrfB is a Mg2+-dependent 3'-5' DNA exonuclease. We show that Leu113 aids in coordinating the 3' end of the DNA substrate, and that a basic loop is important for substrate binding. This work provides insight into the function of a recently discovered bacterial exonuclease important for the repair of MMC-induced DNA adducts.

Although the local application of mitomycin C may prevent epidural adhesion after laminectomy, mitomycin C can induce neurotoxicity in optic and acoustic nerves at high concentrations. To determine the safe concentration range for mitomycin C, cotton pads soaked with mitomycin C at different concentrations (0.1, 0.3, 0.5, and 0.7 mg/mL) were immediately applied for 5 minutes to the operation area of rats that had undergone laminectomy at L1. Rat sciatic nerves, instead of dorsal nerves, were used in this study. The results showed that mitomycin C at 0.1-0.5 mg/mL did not damage the structure and function of the sciatic nerve, while at 0.7 mg/mL, mitomycin C significantly reduced the thickness of the sciatic nerve myelin sheath compared with lower concentrations, though no functional change was found. These experimental findings indicate that the local application of mitomycin C at low concentrations is safe to prevent scar adhesion following laminectomy, but that mitomycin C at high concentrations (> 0.7 mg/mL) has potential safety risks to peripheral nerve structures.

This study aimed at describing an alternative surgical technique to the insertion of a ventilation tube in the tympanic membrane: myringotomy by radiofrequency alone and associated with mitomycin C.

The purpose of this study was to assess the efficacy of verapamil (20 microM) and hyperthermia (42 degrees C) as modifiers of mitomycin C (MMC), used at different concentrations, in inhibiting the growth of human gastric adenocarcinoma (AGS) cells. Combined verapamil and hyperthermia treatment resulted in a significant decrease in cell count by 72.2% as compared with the control value. Verapamil drastically enhanced the growth-inhibitory activity of MMC at high concentration against AGS cells by 67.5% and had no effect at intermediate and low concentrations. Hyperthermia did not enhance the effect of MMC on AGS cells. The modalities analyzed in this study require further investigation and may have potential for in vivo studies on gastric cancer therapy in the near future.

The aim of the study is to assess the outcomes of transconjunctival mitomycin C (MMC)-augmented revision in eyes with failed trabeculectomy.

BACKGROUND Intrauterine adhesion (IUA) is a common reproductive system disease in women, characterized by endometrial stromal cell proliferation, increasing fibroblasts and increasing extracellular matrix secretion. The purpose of this study was to investigate the effect of mitomycin C on reducing endometrial fibrosis for IUA. MATERIAL AND METHODS Firstly, a rat IUA model was constructed by intrauterine mechanical injury. The endometrial stromal cells and fibroblasts were isolated and treated with mitomycin C. After that, Cell Counting Kit-8 (CCK-8) assay was used to investigate the endometrial stromal cell viability. Furthermore, cell cycle and apoptosis assays of endometrial stromal cells and fibroblasts were performed, respectively. Finally, the cell viability of human endometrial cells or human uterus adhesion fibroblasts treated with mitomycin C was determined using CCK-8 assay with or without estradiol. RESULTS Endometrial stromal cells were isolated from a rat IUA model. Cell cycle assay results showed that mitomycin C inhibited cell viability and promoted G1 cell cycle arrest and apoptosis in rat IUA endometrial stromal cells. Fibroblasts were also isolated from the rat IUA model. We found that mitomycin C inhibited the synthesis and secretion of collagen type I by western blotting analysis. Furthermore, mitomycin C promoted G1 cell cycle arrest and apoptosis in IUA rat uterine fibroblasts. We found that estradiol decreased the inhibitory effects of cell viability of human endometrial cells and human uterus adhesion fibroblasts by mitomycin C. CONCLUSIONS Our findings revealed that mitomycin C could reduce endometrial fibrosis for intrauterine adhesion.

To evaluate the surgical outcomes of repeat trabeculectomy augmented with risk factor adjusted mitomycin C (MMC) exposure in eyes with previous failed trabeculectomy.

To determine the safety and efficacy of mitomycin C (MMC) injection versus sponge during trabeculectomy.

To identify functions of the fragile tumour suppressor gene, FHIT, matched pairs of Fhit-negative and -positive human cancer cell clones, and normal cell lines established from Fhit -/- and +/+ mice, were stressed and examined for differences in cell cycle kinetics and survival. A larger fraction of Fhit-negative human cancer cells and murine kidney cells survived treatment with mitomycin C or UVC light compared to matched Fhit-positive cells; approximately 10-fold more colonies of Fhit-deficient cells survived high UVC doses in clonigenic assays. The human cancer cells were synchronised in G1, released into S and treated with UVC or mitomycin C. At 18 h post mitomycin C treatment approximately 6-fold more Fhit-positive than -negative cells had died, and 18 h post UVC treatment 3.5-fold more Fhit-positive cells were dead. Similar results were obtained for the murine -/- cells. After low UVC doses, the rate of DNA synthesis in -/- cells decreased more rapidly and steeply than in +/+ cells, although the Atr-Chk1 pathway appeared intact in both cell types. UVC surviving Fhit -/- cells appear transformed and exhibit >5-fold increased mutation frequency. This increased mutation burden could explain the susceptibility of Fhit-deficient cells in vivo to malignant transformation.

In our previous study, we showed that discarded cardiac tissue from the right atrial appendage and right ventricular myocardium is an available source of functional endothelial and smooth muscle cells for regenerative medicine and tissue engineering. In the study, we aimed to find out what benefits are given by vascular cells from cardiac explants used for seeding on vascular patches engrafted to repair vascular defects in vivo. Additionally, to make the application of these cells safer in regenerative medicine we tested an in vitro approach that arrested mitotic division to avoid the potential tumorigenic effect of dividing cells. A tissue-engineered construction in the form of a patch based on a polycaprolactone-gelatin scaffold and seeded with endothelial and smooth muscle cells was implanted into the abdominal aorta of immunodeficient SCID mice. Aortic patency was assessed using ultrasound, MRI, immunohistochemical and histological staining. Endothelial and smooth muscle cells were treated with mitomycin C at a therapeutic concentration of 10 μg/ml for 2 h with subsequent analysis of cell proliferation and function. The absence of the tumorigenic effect of mitomycin C-treated cells, as well as their angiogenic potential, was examined by injecting them into immunodeficient mice. Cell-containing patches engrafted in the abdominal aorta of immunodeficient mice form the vessel wall loaded with the appropriate cells and extracellular matrix, and do not interfere with normal patency. Endothelial and smooth muscle cells treated with mitomycin C show no tumorigenic effect in the SCID immunodeficient mouse model. During in vitro experiments, we have shown that treatment with mitomycin C does not lead to a decrease in cell viability. Despite the absence of proliferation, mitomycin C-treated vascular cells retain specific cell markers, produce specific extracellular matrix, and demonstrate the ability to stimulate angiogenesis in vivo. We pioneered an approach to arresting cell division with mitomycin C in endothelial and smooth muscle cells from cardiac explant, which prevents the risk of malignancy from dividing cells in vascular surgery. We believe that this approach to the fabrication of tissue-engineered constructs based on mitotically inactivated cells from waste postoperative material may be valuable to bring closer the development of safe cell products for regenerative medicine.

BRCA2 is crucial for repairing DNA double-strand breaks with high fidelity, and loss of BRCA2 increases the risks of developing breast and ovarian cancers. Herein, we show that BRCA2 is inactively mutated in 10% of gastric and 7% of colorectal adenocarcinomas, and that this inactivation is significantly correlated with microsatellite instability. Villin-driven Brca2 depletion promotes mouse gastrointestinal tumor formation when genome instability is increased. Whole-genome screening data showed that these BRCA2 monoallelic and biallelic mutant tumors were selectively inhibited by mitomycin C. Mechanistically, mitomycin C provoked double-strand breaks in cancer cells that often recruit wild-type BRCA2 for repair; the failure to repair double-strand breaks caused cell-cycle arrest at the S phase and p53-mediated cell apoptosis of BRCA2 monoallelic and biallelic mutant tumor cells. Our study unveils the role of BRCA2 loss in the development of gastrointestinal tumors and provides a potential therapeutic strategy to eliminate BRCA2 monoallelic and biallelic mutant tumors through mitomycin C.

Intraabdominal adhesions remain a significant cause of morbidity and mortality. Moreover, intraabdominal adhesions can develop in more than 50% of abdominal operations.

Phellinus linteus is a fungus distributed throughout Japan, Korea and China. Boiled water-soluble extracts from P. linteus (PLW) have shown anti-tumor and immunomodulatory properties in experiments done by intraperitoneal treatment, or in in vitro cell cultures. This is the first investigation on how oral administration of PLW influences immune responses. Here, we established immunodeficient mice by mitomycin C (MMC) and then researched how PLW influenced plaque-forming cell (PFC) production and populations of cytokine [interferon- (IFNgamma-) and interleukin-4 (IL-4)]-producing T lymphocytes. PLW samples were administered orally for 19 days (1, 2 or 4 g/kg/day). PFC assay was followed using Jerne's method. IFN- and IL-4-producing T lymphocyte populations were measured by flow-activated cell sorter (FACS). These assays were conducted the day after the last oral administration. MMC groups were given MMC (1 mg/kg/day) intraperitoneally for 6 days with PLW administration. The number of PFC per 10(6) spleen cells increased significantly in the PLW (2 g/kg/day) group when compared with the MMC-control (P < 0.05) while populations of IFNgamma- and IL-4-producing T lymphocytes decreased by MMC treatment. However, the PLW group tended to increase more than the MMC-control. Our results indicated that PLW augments the immune response of the spleen in MMC-induced immunodeficient mice.