title: Silver nanoparticles protect human keratinocytes against UVB radiation-induced DNA damage and apoptosis: potential for prevention of skin carcinogenesis.
abstract: Ultraviolet (UV)-B radiation from the sun is an established etiological cause of skin cancer, which afflicts more than a million lives each year in the United States alone. Here, we tested the chemopreventive efficacy of silver-nanoparticles (AgNPs) against UVB-irradiation-induced DNA damage and apoptosis in human immortalized keratinocytes (HaCaT). AgNPs were synthesized by reduction-chemistry and characterized for their physicochemical properties. AgNPs were well tolerated by HaCaT cells and their pretreatment protected them from UVB-irradiation-induced apoptosis along with significant reduction in cyclobutane-pyrimidine-dimer formation. Moreover, AgNPs pre-treatment led to G1-phase cell-cycle arrest in UVB-irradiated HaCaT cells. AgNPs were efficiently internalized in UVB-irradiated cells and localized into cytoplasmic and nuclear compartments. Furthermore, we observed an altered expression of various genes involved in cell-cycle, apoptosis and nucleotide-excision repair in HaCaT cells treated with AgNPs prior to UVB-irradiation. Together, these findings provide support for potential utility of AgNPs as novel chemopreventive agents against UVB-irradiation-induced skin carcinogenesis.
  
  
  BACKGROUND
  Excessive exposure to the sun is known to increase the risk of skin cancer due to DNA damage. In this work, the authors tested the use of silver nanoparticles as protective agents against ultraviolet radiation. The positive results may open a door for the use of silver nanoparticle as novel agents in the future.
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
authors: Sumit
authors: S
authors: Arora
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
authors: Nikhil
authors: N
authors: Tyagi
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
authors: Arun
authors: A
authors: Bhardwaj
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA; Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL, USA.
authors: Lilia
authors: L
authors: Rusu
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
authors: Rohan
authors: R
authors: Palanki
authors: Alabama State University, Montgomery, AL, USA.
authors: Komal
authors: K
authors: Vig
authors: Alabama State University, Montgomery, AL, USA.
authors: Shree R
authors: SR
authors: Singh
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA; Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA.
authors: Ajay P
authors: AP
authors: Singh
authors: Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL, USA.
authors: Srinivas
authors: S
authors: Palanki
authors: Auburn University Research Instrumentation Facility - Advanced Microscopy and Imaging Laboratory, Auburn, AL, USA.
authors: Michael E
authors: ME
authors: Miller
authors: Department of Pathology, College of Medicine, University of South Alabama, Mobile, AL, USA.
authors: James E
authors: JE
authors: Carter
authors: Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA. Electronic address: seemasingh@health.southalabama.edu.
authors: Seema
authors: S
authors: Singh
mesh_terms: D016588:Anticarcinogenic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D012878:Skin Neoplasms / Q000517:prevention & control; D014466:Ultraviolet Rays
chemical_list: D016588:Anticarcinogenic Agents; D012834:Silver
keywords: Apoptosis; Cyclobutane pyrimidine dimers (CPDs); DNA damage; Keratinocytes; Nucleotide excision repair (NER); Silver nanoparticles; Ultraviolet radiations