Taurine Enhances Anticancer Activity of Cisplatin in Human Cervical Cancer Cells - Advances in Experimental Medicine and Biology - page 176

chemotherapy, combined treatment of natural resources was investigated (Saif et al.
2009 ; Ghavami et al. 2011 ; Suganuma et al. 2011 ) .
Taurine is a sulfur-containing amino acid. It is a low molecular weight amino
acid and forms zwitterions. Taurine is one of the most abundant free amino acids in
animal tissues and biological fluids (Barbeau 1975 ). 20 to 30 years ago, taurine has
not been known to any other physiological activity except for conjugation of bile
acids (Danielsson and Sjövall 1975 ). Recently several studies reported that taurine
has a variety of biological functions including antioxidant activity, brain develop-
ment, activation of retinal photoreceptor, contraction of the heart muscle, regulation
of osmotic pressure, and maintenance of the immune system (Huxtable 1992 ) .
Some recent researches show the protective effects of taurine against anticancer
drugs in vivo. Taurine prevents cardiotoxicity induced by doxorubicin in chick and
mice (Hamaguchi et al. 1988 ; Hamaguchi et al. 1989 , Ito et al. 2009 ) . In addition,
taurine has protective effects against cisplatin-induced renal interstitial fibrosis and
nephrotoxicity (Saad and Al-Rikabi 2002 ; Sato et al. 2002 ). But antitumor effect of
taurine has rarely been investigated. Therefore, the present study was conducted to
investigate the anticancer effects and mechanisms of single treatment of taurine or
co-treatment of cisplatin with taurine in HeLa cells.

19.2 Methods

19.2.1 Cell Culture

Human cervical cancer HeLa cells were purchased from KCLB (Korea Cell Line
Bank; Seoul, South Korea). Cells were cultured in RPMI1640 (Welgene, Daegu,
South Korea) supplemented with 100 U/ml penicillin, 100 m g/ml streptomycin
(Welgene, Daegu, South Korea), and heat-inactivated 10%FBS (fetal bovine serum;
Welgene, Daegu, South Korea) in 5% CO 2 atmosphere at 37°C. Cells were routinely
subcultured when about 80% confluent.

19.2.2 Measurement of Cell Viability

Cell viability was measured by the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetra-
zolium bromide (MTT) assay. Cells were plated into 96-well plates at 3,000 cells
per well. Cisplatin and taurine were treated with different concentrations for 24, 48,
and 72 h. At the end of the treatment, 20 ml MTT solution (5 mg/ml in PBS; Sigma,
St. Louis, MO, USA) was added in each well and incubated at 37°C for 4 h. Formed
formazan crystals were dissolved in 200 ml dimethyl sulfoxide (DMSO) and mea-
sured by a microplate reader (EL800, BioTEK Instruments Inc., Winooski, VT,
USA) at a wavelength of 540 nm.