The development of nanotechnology has allowed the identification of unique properties in nanomaterials that
have, in turn, led to the development of commercial applications in many fields, such as chemical catalysis,
semiconductors, water purification, cosmetics, microelectrodes, biosensors, the food industry, biomedicine,
etc. In 2009, developers generated more than $1 billion from the sale of nanomaterials, and the market for
nanotechnology is expected to grow to 75.8 billion by 2020 with several hundreds of thousands of jobs. Thus
the levels of human exposure to anthropogenic nanoparticles will substantially increase. As an important
transition metal, nickel nanoparticles (Nano-Ni) have wide ranging applications in the fields of batteries,
electrical conductors, permanent magnets, magnetic fluids, magnetic recording media, solar energy
absorption, fuel cell electrodes, and catalysts. In addition, due to structural and inherent chemical and physical
properties, nickel alloy nanomaterials have received special interest in biomedical applications. In this
proposal, we selected Nano-Ni as a model metal nanoparticle because of its wide industrial interest and
biological and medical applications. Based on our preliminary data, our working hypothesis is that Nano-Ni
can cause oxidative stress and DNA damage in lung epithelial cells, and long-term exposure to Nano-
Ni results in DNA repair deficiency by down-regulating Rad52, increased genomic instability and cell
transformation through up-regulation of miR-210, and nuclear accumulation of the hypoxia inducible
factor 1a (HIF-1a). The following two Specific Aims will be pursued. Specific Aim 1. Examine the role of
HIF-1a pathway in Nano-Ni-induced genotoxic effects in vitro and in vivo. We will first examine whether
exposure to Nano-Ni will induce DNA damage in normal human lung epithelial cells BEAS-2B and in mice by
measuring the phosphorylation level of ataxia telangiectasia mutated (ATM) at Ser1981 and p53 at Ser15, and
expression level of Rad52 and phosphorylated histone H2AX (¿-H2AX). We will then investigate the role of
HIF-1a in Nano-Ni-induced DNA damage by using: (1) HIF-1a - specific siRNA; and (2) HIF-1a knock-out
cells. Specific Aim 2. Examine whether exposure to Nano-Ni causes down-regulation of Rad52 through
up-regulation of miR-210 induced by HIF-1¿ activation during Nano-Ni-induced cell transformation. We
will first determine whether long-term exposure to low doses of Nano-Ni will induce normal BEAS-2B cells to
transform. We will then measure the levels of Rad52, miR-210 and HIF-1a in cells with long-term exposure to
Nano-Ni and in Nano-Ni-transformed cells. Finally, we will explore the role of Rad52 in Nano-Ni-induced cell
transformation through overexpression or knockout of Rad52.