Related Experiment Videos
Selective toxicity of rhodamine 123 in carcinoma cells in vitro
Abstract:
The study of mitochondria in situ has recently been facilitated through the use of rhodamine 123, a mitochondrial-specific fluorescent dye. It has been found to be nontoxic when applied for short periods to a variety of cell types and has thus become an invaluable tool for examining mitochondrial morphology and function in the intact living cell. In this report, however, we demonstrate that with continuous exposure, rhodamine 123 selectively kills carcinoma as compared to normal epithelial cells grown in vitro. At doses of rhodamine 123 which were toxic to carcinoma cells, the conversion of mitochondrial-specific to cytoplasmic-nonspecific localization of the drug was observed prior to cell death. At 10 microgram/ml, greater than 50% cell death occurred within 7 days in all nine of the carcinoma cell types and lines of different origin studied, while six of six normal epithelial cell types and lines remained unaffected. Cotreating carcinoma cells with 2-deoxyglucose and rhodamine 123 enhanced the inhibition of growth by rhodamine 123 alone in clonogenic survival assays. The observation of the selective toxicity of rhodamine 123 appears to be unique in view of the absence of selective toxicity reported in vitro for the various antitumor agents currently in clinical use. Preliminary results with rhodamine 123 in animal tumor systems indicate antitumor activity for carcinomas.
Insights
Rhodamine 123, a mitochondrial dye, selectively kills carcinoma cells with continuous exposure, unlike normal cells. This finding offers potential for novel cancer therapies targeting mitochondria.
Area of Science:
- Mitochondrial biology
- Cellular toxicology
- Cancer research
Background:
- Rhodamine 123 is a fluorescent dye used to study mitochondria in living cells.
- It is generally considered non-toxic for short-term applications.
- Its utility in visualizing mitochondrial morphology and function is well-established.
Purpose of the Study:
- To investigate the effects of continuous exposure to rhodamine 123 on different cell types.
- To determine if rhodamine 123 exhibits selective toxicity towards cancer cells.
- To explore potential therapeutic applications of rhodamine 123 in cancer treatment.
Main Methods:
- In vitro cell culture of various carcinoma and normal epithelial cell lines.
- Continuous exposure of cells to rhodamine 123 at specific concentrations.
- Monitoring of cell viability, localization of rhodamine 123, and growth inhibition using clonogenic survival assays.
- Co-treatment experiments with 2-deoxyglucose and rhodamine 123.
Main Results:
- Continuous exposure to rhodamine 123 selectively killed nine different carcinoma cell types and lines.
- Normal epithelial cells remained unaffected at toxic doses for carcinoma cells.
- Drug localization shifted from mitochondria to cytoplasm before cell death in carcinoma cells.
- Co-treatment with 2-deoxyglucose enhanced rhodamine 123's growth inhibition.
- Preliminary animal studies suggest antitumor activity against carcinomas.
Conclusions:
- Rhodamine 123 demonstrates selective toxicity against carcinoma cells in vitro, a unique property among current antitumor agents.
- The observed selective toxicity and preliminary in vivo antitumor activity suggest rhodamine 123 as a potential lead for novel cancer therapeutics.
- Further research into the mechanisms of selective toxicity and in vivo efficacy is warranted.