The effective concentration and exposure time of mitomycin-C for the inhibition of lens epithelial cell proliferation in rabbit eyes

You, Yong Sung; Lim, Seong Jung; Chung, Ho Seok; Lee, Young Gee; Kim, Chan Yun; Hong, Young Jae

doi:10.3349/ymj.2000.41.2.185

Cited by 9 publications

(6 citation statements)

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“…The area of the wound was determined using NIH Image 1.6 (public domain image processing and analysis program for the Macintosh developed at the National Institutes of health and available on the Internet at rsb.info.nih.gov/nih-image/), and the percentage of wound healing was calculated by dividing the area of the wound at time X by the area of the wound at time 0 and multiplying by 100. In some experiments, to prevent cell proliferation, which could confound the analysis of cell migration into the wound, cells were preincubated with mitomycin C (10 g/ml) for 1 h at 37°C (50). To confirm that the observed reduction in keratinocyte migration induced by ISO was due to ␤ 2 -AR activation, in some experiments, human keratinocytes were preincubated for 15 min at 37°C in the presence or absence of timolol (20 M), a ␤ 2 -AR antagonist.…”

Section: Methodsmentioning

confidence: 99%

PP2A Activation by β2-Adrenergic Receptor Agonists

Pullar

Chen

Isseroff

2003

Journal of Biological Chemistry

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Understanding the mechanisms that regulate cell migration is important for devising novel therapies to control metastasis or enhance wound healing. Previously, we demonstrated that ␤ 2 -adrenergic receptor (␤ 2 -AR) activation in keratinocytes inhibited their migration by decreasing the phosphorylation of a critical promigratory signaling component, the extracellular signal-related kinase (ERK). Here we demonstrate that ␤ 2 -ARinduced inhibition of migration is mediated by the activation of the serine/threonine phosphatase PP2A. Pretreating human keratinocytes with the PP2A inhibitor, okadaic acid, prevented the ␤ 2 -AR-induced inhibition of migration, either as isolated cells or as a confluent sheet of cells repairing an in vitro "wound" and also prevented the ␤ 2 -AR-induced reduction in ERK phosphorylation. Similar results were obtained with human corneal epithelial cells. In keratinocytes, immunoprecipitation studies revealed that ␤ 2 -AR activation resulted in the rapid association of ␤ 2 -AR with PP2A as well as a 37% increase in association of PP2A with ERK2. Finally, ␤ 2 -AR activation resulted in a rapid and transient 2-fold increase in PP2A activity. Thus, we provide the first evidence that ␤ 2 -AR activation in keratinocytes modulates migration via a novel pathway utilizing PP2A to alter the promigratory signaling cascade. Exploiting this pathway may result in novel therapeutic approaches for control of epithelial cell migration.When skin is wounded, keratinocytes within the epidermis must migrate from the wound edges to re-epithelialize the wound surface (1). One of the best characterized mediators of keratinocyte migration is the epidermal growth factor receptor (EGFR) 1 (2-4). The mitogen-activated protein (MAP) kinases, extracellular signal-related kinase 1 (ERK1) and ERK2, are activated upon EGF binding to its cognate receptor (reviewed in Ref. 5). They are activated by phosphorylation on both conserved threonine and tyrosine residues and inactivated upon dephosphorylation by dual specificity phosphatases, tyrosine phosphatases, and serine/threonine-specific phosphatases (5-9). The activation of ERK is tightly controlled. The MAP kinase pathway is usually only transiently activated, and its constitutive activation is sufficient to cause the oncogenic transformation of some cell types (10). Inhibiting ERK phosphorylation and activation prevents growth factor-induced keratinocyte migration (11), demonstrating the pivotal role of ERK in the keratinocyte promigratory signaling pathways (11-13).In addition to the EGFR, keratinocytes also express high levels of the G-protein-coupled receptor, the ␤ 2 -adrenergic receptor, (␤ 2 -AR) (14, 15), whose functional role in the epidermis has not yet been elucidated. Keratinocytes do not express the ␤ 1 -AR (16). Earlier studies have investigated the role of ␤-ARs in epithelial wound healing and migration, but the results have been paradoxical. ␤-Antagonists have been reported to either delay (17, 18) or enhance (19) corneal epithelial wound healing, and ␤-agon...

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Section: Methodsmentioning

confidence: 99%

PP2A Activation by β2-Adrenergic Receptor Agonists

Pullar

Chen

Isseroff

2003

Journal of Biological Chemistry

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“…[ 13 14 15 16 17 ] To date, only mechanical removal of the LECs by anterior lens capsule (ALC) polishing has been used clinically and other physical or pharmacological methods have not found application due to lack of sensitivity and specificity. [ 18 19 20 21 ] The ultrasound irrigation and aspiration tip was found to be the most effective instrument for mechanical polishing. [ 22 ]…”

Section: Discussionmentioning

confidence: 99%

Impact of anterior capsular polishing on capsule opacification rate in eyes undergoing femtosecond laser-assisted cataract surgery

Sachdev¹,

Soundarya²,

Ramamurthy³

et al. 2020

Indian J Ophthalmol

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Purpose: To evaluate the impact of anterior capsular polishing on capsule opacification and contraction in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS). Methods: This prospective interventional comparative analysis included patients undergoing FLACS between August 2016 and May 2017. The eyes were subdivided into three groups based on the extent of intraoperative anterior capsular polishing performed: complete 360-degree polishing; inferior 180-degree polishing; and no polishing. Visual acuity, posterior capsular opacification (PCO) score, anterior capsular opacification (ACO) grade, and capsulorhexis diameter were evaluated at 1-week, 6-months, and 1-year postoperative visits. Results: The study included 99 eyes of 90 patients. No significant differences were observed between the three groups in ACO grade and capsulorhexis contraction at all follow-up visits. There was a statistically significant difference in PCO grade among the groups at 6-month and 1-year follow-up but it was found to be clinically insignificant. One eye in the no polishing group underwent neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy at the 1-year follow-up visit. Conclusion: A lower incidence of PCO was demonstrated in the 360-degree polishing group, although it was visually insignificant. No significant difference in postoperative capsular contraction was demonstrated between the cohorts up to one-year follow-up.

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“…It has been reported that the efficacy of MMC on the inhibition of rabbit lens epithelial cells in vitro is positively related in a dose-and time-dependent manner [18]. However, the characteristics of MMC-induced lens cell death and the mode of action of MMC on LEC death have not been studied in detail.…”

Section: Introductionmentioning

confidence: 96%

“…To determine cell viability, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used [18]. ·-TN4 cells (5 !…”

Section: Determination Of Cell Viabilitymentioning

confidence: 99%

Mitomycin C-Induced Cell Death in Mouse Lens Epithelial Cells

et al. 2002

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The mode of action of mitomycin C (MMC)-induced cell death in lens epithelia was investigated using cell culture system. The cytotoxicity of MMC on α-TN4 mouse lens epithelial cells (LECs) was measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)-based assay. To determine the type of cell death induced by MMC, we stained LECs with acridine orange and ethidium bromide, and performed TUNEL assay and electron microscopic examination. The activation of MMC was also investigated with N-acetly-L-cystein (NAC), a free radical scavenger, and dicumarol, an inhibitor of DT-diaphorase, to analyze one- and two-electron reduction pathways involved in the activation of MMC. MTT assay showed that 400 µg/ml of MMC decreased the cell viability of the control cells to 45%, and the cytotoxicity of MMC on α-TN4 cells was increased in a dose-dependent manner. Based on the results obtained from acridine orange and ethidium bromide staining, the TUNEL assay, and transmission electron microscopic examination, we confirmed that MMC-induced cell death, at 400 µg/ml of MMC, occurs with necrosis as well as apoptotis. The treatment of cells with 2 mM NAC for 1 h or 20 µM dicumarol for 30 min, prior to 5 min of MMC (400 µg/ml) treatment, restored the growth suppression to 76 and 80% of the control level, respectively. In addition, the cotreatment of cells with NAC and dicumarol restored cell viability to 90% of the control level. The cellular death in MMC-treated LECs showed the involvement of oxidative stress in this apoptosis accounting for 22% of the observed cell death at 400 µg/ml of MMC.

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The effective concentration and exposure time of mitomycin-C for the inhibition of lens epithelial cell proliferation in rabbit eyes

Cited by 9 publications

References 0 publications

PP2A Activation by β2-Adrenergic Receptor Agonists

PP2A Activation by β2-Adrenergic Receptor Agonists

Impact of anterior capsular polishing on capsule opacification rate in eyes undergoing femtosecond laser-assisted cataract surgery

Mitomycin C-Induced Cell Death in Mouse Lens Epithelial Cells

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