Alterations in metal toxicity and metal-induced metallothionein gene expression elicited by growth medium calcium concentration

Abstract

The calcium content of the growth medium has been shown to influence the growth and differentiation of primary epithelial cells in culture. The goal of the present study was to determine if growth medium calcium concentration could influence the susceptibility to metal toxicity and metallothionein gene expression of an immortalized human prostate-derived epithelial cell line (RWPE-1). The RWPE-1 cell line was grown in medium containing either 0.1 or 1.4 mM calcium. Confluent cells were exposed to either Zn(+2) (50, 100, or 150 microM) or Cd(+2) (3, 6, or 12 microM) for 13 days, and cell toxicity and MT gene expression were determined along the time course of exposure. It was demonstrated that the calcium content of the growth medium had a marked influence on Zn(+2) toxicity and a lesser but significant effect on Cd(+2) toxicity to the RWPE-1 cells. Calcium concentration of the growth medium was also shown to alter the accumulation of MT-1/2 protein and MT-1E, MT-1X, and MT-2A mRNAs. It was shown that MT-1/2 protein was markedly increased for metal-exposed cells grown in medium containing 0.1 mM calcium; however, the increased expression did not cause an increase in the resistance of the cells to Zn(+2) or Cd(+2) exposure. These observations show that growth medium calcium concentration can influence metal toxicity and the pattern of expression of the MT mRNAs and protein for RWPE-1 cells. The results suggest that caution should be exercised when comparing toxicological responses between cell lines that may be grown in growth formulations differing in calcium concentration.

Large-scale chromatin structure of inducible genes: transcription on a condensed, linear template

“…For the MT gene cluster, we observed 4-50-fold increases in MT2A transgene expression with 2-16 h Zn induction, respectively (Table II). This increase is comparable to reported increases for the endogenous MT2A gene in human prostate epithelial cells and in CHO cells after gene amplification Singh et al, 2008). Differences in primer efficiency prevented an accurate normalization to endogenous gene expression levels.…”

Citrullinated vimentin mediates development and progression of lung fibrosis

“…As smoking is known to be associated with IPF (2,13,14), and both Cd and CB are present in CS, we first investigated the accumulation of Cd and CB in subjects with IPF. MT has been considered as an indicator of metal exposure, including Cd (34,35). Both MT-1E and MT-2A mRNA were increased in lung macrophages from subjects with IPF (fig.…”

Investigating on the influence mechanism of sausage of sea bass on calcium absorption and transport based on Caco-2 cell monolayer model

“…The concentration of calcium affected the expression of MT-2. In keratinocyte serum-free medium (K-SFM), 4 mM Ca 2+ significantly decreased the expression of MT-1/2 proteins in RWPE-1 cells exposed to Cd 2+ ( 51 ). The expression of MT-2 in the positive control and fish sausage groups was down-regulated, which may be due to the decrease in MT-2 expression due to the increased calcium concentration.…”

“…The enrichment pathways included hypoxia-inducible factor-1 (HIF-1) signaling pathway, ubiquitin-mediated protein hydrolysis, endocytosis, and Janus kinase-signal transducer, an activator of the transcription (JAK-STAT) signaling pathway. The HIF-1 signaling pathway plays an important role in autoimmune diseases (51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63). Endocytosis and ubiquitinmediated proteolysis belong to the cellular immune pathway (64).…”