In vitro analysis of the relationships between metallothionein expression and cisplatin sensitivity of non-small cellular lung cancer cells.

BACKGROUND Cisplatin-based therapy is a pivotal type of chemotherapy for non-small cell lung cancer (NSCLC) and chemoresistance to cisplatin represents one of the most significant barriers to improving long-term clinical outcomes. MATERIALS AND METHODS The present study aimed at examining metallothionein (MT) expression in six NSCLC cell lines as well as examining effects of exposure to cisplatin on MT expression in the most cisplatin-resistant (97/97) and the cisplatin-sensitive (DV90) cell lines. RESULTS The most cisplatin-resistant NSCLC cell line [97/97; (IC50)=4.659 μM] exposed to the highest concentration of cisplatin (10 μM) exhibited decreased nuclear MT expression (MTn=6) compared to cells cultured in medium with a lower concentration of cisplatin (0, 1 and 5 μM) (MTn=12). A higher cytoplasmic metallothionein expression (MTc=6) was found in the 97/97 cell line exposed to the highest concentration of cisplatin (10 μM), compared to cells cultured in the medium with lower concentrations of cisplatin (0, 1 and 5 μM) (MTc=3). The most cisplatin-sensitive NSCLC cell line (DV90; IC50=0.184 μM) was characterized by a significant decrease of both nuclear and cytoplasmic MT expression with increasing cisplatin concentrations (5 vs. 10 μM). CONCLUSION Nuclear and cytoplasmic expression of MT has no significant impact on the development of cisplatichemoresistance in NSCLC cell lines. The present study suggests that cisplatin resistance in NSCLC is metallothionein-independent.