Nickel-induced alterations in human renal epithelial cells

Area of Science:

• Oncology
• Cell Biology
• Environmental Toxicology

Background:

• Cellular malignancy involves accumulating genetic damage in regulatory genes.
• Immortalization, or escaping senescence, is a critical early step in cancer development.
• Nickel compounds are known environmental carcinogens.

Purpose of the Study:

• To investigate the role of nickel (Ni2+) in the immortalization and malignant transformation of normal human kidney epithelial (NHKE) cells.
• To identify specific genetic alterations associated with nickel-induced cellular changes.
• To explore alterations in growth factor signaling during malignant progression.

Main Methods:

• In vitro culture of NHKE cells with Ni2+ exposure.
• Co-treatment with v-Ha-ras oncogene to assess tumorigenicity.
• DNA sequencing to analyze mutations in key genes, specifically p53.
• Analysis of cellular responses and receptor expression for epidermal growth factor (EGF) and transforming growth factor-beta (TGF-β).

Main Results:

• Ni2+ treatment successfully immortalized NHKE cells (designated IHKE cells).
• Combined Ni2+ and v-Ha-ras treatment induced full tumorigenicity in athymic nude mice.
• Sequence analysis revealed a point mutation (T-->C transition at codon 238) in the p53 gene of IHKE cells.
• Significant changes in cellular responses and receptor expression for EGF and TGF-β were observed during malignant progression.

Conclusions:

• Nickel-induced p53 gene mutation is implicated in the immortalization of NHKE cells.
• The study demonstrates a pathway for nickel-induced malignant transformation involving p53 mutation and oncogene cooperation.
• Alterations in EGF and TGF-β signaling pathways are associated with in vitro malignant progression.