5-Fluorouracil induces apoptosis in rat cardiocytes through intracellular oxidative stress.
BACKGROUND
Cardiotoxicity is a major complication of anticancer drugs, including anthracyclines and 5-fluorouracil(5-FU) and it can have detrimental effects both in patients and workers involved in the preparation of chemotherapy.


METHODS
Specifically, we have assessed the effects of increasing concentrations of 5-FU and doxorubicin (DOXO) on proliferation of H9c2 rat cardiocytes and HT-29 human colon adenocarcinoma cells by MTT assay. Cells were treated for 24, 48 and 72 h with different concentrations of the two drugs alone or with 5-FU in combination with 10(-4) M of levofolene (LF).


RESULTS
5-FU induced a time- and dose-dependent growth inhibition in both cell lines. The 50% growth inhibition (IC:50) was reached at 72 h with concentrations of 4 μM and 400 μM on HT-29 and H9c2, respectively. The addition of LF to 5-FU enhanced this effect. On the other hand, the IC:50 of DOXO was reached at 72 h with concentrations of 0.118 μM on H9c2 and of 0.31 μM for HT-29. We have evaluated the cell death mechanism induced by 50% growth inhibitory concentrations of 5-FU or DOXO in cardiocytes and colon cancer cells. We have found that the treatment with 400 μM 5-FU induced apoptosis in 32% of H9c2 cells. This effect was increased by the addition of LF to 5-FU (38% of apoptotic cells). Apoptosis occurred in only about 10% of HT-29 cells treated with either 5-FU or 5-FU and LF in combination. DOXO induced poor effects on apoptosis of both H9c2 and HT-29 cells (5-7% apoptotic cells, respectively). The apoptosis induced by 5-FU and LF in cardiocytes was paralleled by the activation of caspases 3, 9 and 7 and by the intracellular increase of O(2-) levels.


CONCLUSIONS
These results suggest that cardiotoxic mechanism of chemotherapy agents are different and this disclose a new scenario for prevention of this complication.
Occupational Medicine, Hygiene and Industrial Toxicology Section, Department of Experimental Medicine, Second University of Naples, Naples, Italy.
Monica
M
Lamberti
Stefania
S
Porto
Monica
M
Marra
Silvia
S
Zappavigna
Anna
A
Grimaldi
Daniela
D
Feola
Delia
D
Pesce
Silvio
S
Naviglio
Annamaria
A
Spina
Nicola
N
Sannolo
Michele
M
Caraglia
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology / Q000633:toxicity; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology / Q000633:toxicity; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology* / Q000633:toxicity; D019073:HT29 Cells; D006801:Humans; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats
D000903:Antibiotics, Antineoplastic; D000964:Antimetabolites, Antineoplastic; D004317:Doxorubicin; D053148:Caspase 3; D005472:Fluorouracil