• Radiation Oncology Journal
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• v.26 no.3
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• pp.166-172
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• 2008

Purpose: The measurement of radiosensitivity of individuals is useful in radiation therapy. Unfortunately, the measurement of radiation survival using a clonogenic assay, which is the established standard, can be difficult and time consuming. The aim of this study is to compare radiosensitivity results obtained from the MTT and clonogenic assays, and to evaluate whether the MTT assay can be used on clinical specimens. Materials and Methods: HCT-8, LoVo, CT-26, and WiDr were the colon cancer cell lines used for this study. The clonogenic assay was performed to obtain the cell survival curves and surviving fractions at a dose of 2 Gy ($SF_2$) as the standard technique for radiosensitivity. Also, the MTT assay was performed for each of the cell lines (in vitro). To simulate clinical specimens, the cell lines were inoculated into nude mice, removed when the tumors reached 1 cm in diameter, and chopped. Next, the tumors were subjected to the same process involved with the MTT assay in vitro. The inhibition rates (IR) of 10 Gy or 20 Gy of irradiation for in vitro and ex vivo were calculated based on the optical density of the MTT assay, respectively. Results: According to $SF_2$ and the cell survival curve, the HCT-8 and WiDr cell lines were more resistant to radiation than LoVo and CT-26 (p<0.05). The IR was measured by in vitro. The MTT assay IR was 17.3%, 21%, 30% and 56.5% for the WiDr, HCT-8, LoVo and CT-26 cell lines, respectively. In addition, the IR measured ex vivo by the MTT assay was 23.5%, 26%, 38% and 53% in the HCT-8, WiDr, LoVo and CT-26 tumors, respectively. Conclusion: The radiosensitivity measured by the MTT assay was correlated with the measures obtained from the clonogenic assay. This result highlights the possibility that the MTT assay could be used in clinical specimens for individual radiosensitivity assays.

• Biomedical Science Letters
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• v.20 no.2
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• pp.85-95
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• 2014

Activation of the epidermal growth factor receptor (EGFR) and downstream signaling pathways have been implicated in causing resistance to EGFR-targeted therapy in solid tumors, including the head and neck tumors. To investigate the mechanism of antiproliferation to EGFR inhibition in oral cancer, we compared EGFR tyrosine kinase inhibitor (Gefitinib, Iressa, ZD1839) with respect to its inhibitory effects on three kinases situated downstream of EGFR: MAPK, Akt, and glycogen synthase kinase-$3{\beta}$ (GSK-$3{\beta}$). We have demonstrated that ZD1839 induces growth arrest and apotosis in oral cancer cell lines by independent of EGFR-mediated signaling. An exposure of oral cancer cells to ZD1839 resulted in a dose dependent up-regulation of the cyclin-dependent kinase inhibitor p21 and p27, down regulation of cyclin D1, inactivation of GSK-$3{\beta}$ and of active MAPK. In resistant cells, GSK-$3{\beta}$ is constitutively active and its activity is negatively regulated primarily through Ser 9 phosphorylation and further enhanced by Tyr216 phosphorylation. These results showed that the resistance to the antiproliferative effects of ZD1839, in vitro was associated with uncoupling between EGFR and MAPK inhibition, and that GSK-$3{\beta}$ activation and degradation of its target cyclin D1 were indicators of high cell sensitivity to ZD1839. In conclusion, our data show that the uncoupling of EGFR with mitogenic pathways can cause resistance to EGFR inhibition in oral cancer.

• Archives of Pharmacal Research
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• v.25 no.4
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• pp.550-555
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• 2002

The discovery and development of the taxane class of antitumor compounds represent significant advances in the treatment of patients with a variety of malignancies. These drugs are effectively used in the treatment of breast cancer. In this study we evaluated the efficacy of fractionated usage of both paclitaxel and docetaxel as a single agent in the breast cancer cell line MCF-7. It has been shown that the cytotoxic effect of paclitaxel was increased when the divided $IC_{50}$ concentrations were used sequentially and in contrast to paclitaxel, cytotoxic effect of docetaxel was decreased with the same schema and the single dose of $IC_{50}$ concentration was optimal. The cause of the difference between the cytotoxic effects of two agents with this schedule is obscure. Demonstrating mechanisms, which are responsible for these differences, will be important for more rational use of taxoids and to provide basis for the following clinical trials.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5023-5028
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• 2014

Sendai virus strain Tianjin is a novel genotype. Here, we investigate the antitumor and proapoptotic effects of ultraviolet-inactivated Sendai virus strain Tianjin (UV-Tianjin) on human breast cancer MDA-MB-231 cells in vitro, as well as the involvement of the apoptotic pathway in the mechanism of UV-Tianjin-induced antitumor effects. MTT assays showed that treatment with UV-Tianjin dose-dependently inhibited the proliferation of MDA-MB-231 cells but not normal MCF 10A breast epithelium cells. Hoechst staining and flow cytometric analysis revealed that UV-Tianjin induced apoptosis of MDA-MB-231 cells in a dose-dependent manner. Moreover, UV-Tianjin treatment resulted in reduction in the mitochondria membrane potential (MMP) and release of cytochrome complex (cyt c) via regulation of Bax and Bcl-2, as well as activation of caspase-9, caspase-3, Fas, FasL and caspase-8 in MDA-MB-231 cells. In summary, our study suggests that UV-Tianjin exhibits anticancer activity in human breast cancer MDA-MB-231 cells through inducing apoptosis, which may involve both the endogenous mitochondrial and exogenous death receptor pathways.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1341-1344
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• 2005

Bioassay-guided fractionation of $CHCl_{3}$ extract from the fermentation broth of a sponge Mycale plumose-derived actinomycete Saccharopolyspora sp. nov., led to the isolation of two known prodigiosin analogs - metacycloprodigiosin (1) and undecylprodigiosin (2). These compounds exhibited significant cytotoxic activities against five cancer cell lines: P388, HL60, A-549, BEL­7402, and SPCA4. This is the first report on the significant cytotoxicity of metacycloprodigiosin (1) against human cancer cell lines.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5659-5665
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• 2014

Background: To investigate the antioxidant value and anticancer functions of mitragynine (MTG) and its silane-reduced analogues (SRM) in vitro. Materials and Methods: MTG and SRM was analyzed for their reducing power ability, ABTS radical inhibition and 1,1-diphenyl-2-picryl hydrazylfree radicals scavenging activities. Furthermore, the antiproliferation efficacy was evaluated using MTT assay on K 562 and HCT116 cancer cell lines versus NIH/3T3 and CCD18-Co normal cell lines respectively. Results: SRM and MTG demonstrate moderate antioxidant value with ABTS assay (Trolox equivalent antioxidant capacity (TEAC): $2.25{\pm}0.02$ mmol trolox / mmol and $1.96{\pm}0.04$ mmol trolox / mmol respectively) and DPPH ($IC_{50}=3.75{\pm}0.04mg/mL$ and $IC_{50}=2.28{\pm}0.02mg/mL$ respectively). Both MTG and SRM demonstrate equal potency ($IC_{50}=25.20{\pm}1.53$ and $IC_{50}=22.19{\pm}1.06$ respectively) towards K 562 cell lines, comparable to control, betulinic acid (BA) ($IC_{50}24.40{\pm}1.26$). Both compounds showed concentration-dependent cytototoxicity effects and exert profound antiproliferative efficacy at concentration > $100{\mu}M$ towards HCT 116 and K 562 cancer cell lines, comparable to those of BA and 5-FU (5-Fluorouracil). Furthermore, both MTG and SRM exhibit high selectivity towards HCT 116 cell lines with selective indexes of 3.14 and 2.93 respectively compared to 5-FU (SI=0.60). Conclusions: These findings revealed that the medicinal and nutitional values of mitragynine obtained from ketum leaves that growth in tropical forest of Southeast Asia and its analogues does not limited to analgesic properties but could be promising antioxidant and anticancer or chemopreventive compounds.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.68-76
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• 2004

Mistletoe lectin has been reported to induce apoptosis in different cancer cell lines in vitro and to show antitumor activity against a variety of tumors in animal models. We previously demonstrated the Korean mistletoe lectin (Viscum album var. coloratum, VCA)-induced apoptosis by down-regulation of Bcl-2 and telomerase activity and by up-regulation of Bax through p53- and p21-independent pathway in hepatoma cells. In the present study, we observed the induction of apoptotic cell death through activation of caspase-3 and the inhibition of telomerase activity through transcriptional down-regulation of hTERT in the VCA-treated A253 cells. We also observed the inhibition of telomerase activity and induction of apoptosis resulted from dephosphorylation of Akt in the survival signaling pathways. In addition, combining VCA with the inhibitors of phosphatidylinositol 3-kinase (PI3-kinase) upstream of Akt, wortmannin and LY294002 showed an additive inhibitory effect of telomerase activity. In contrast, the inhibitor of protein phosphatase 2A (PP2A), okadaic acid inhibited VCA-induced dephosphorylation of Akt and inhibition of telomerase activity. Taken together, VCA induces apoptotic cell death through Akt signaling pathway in correlated with the inhibition of telomerase activity and the activation of caspase-3. From these results, together with our previous studies, we suggest that VCA triggers molecular changes that resulting in the inhibition of cell growth and the induction of apoptotic cell death of cancer cells, which suggest that VCA may be useful as chemotherapeutic agent for cancer cells.

• Journal of Pharmacopuncture
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• v.20 no.3
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• pp.207-212
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• 2017

Objectives: Study of the mechanisms involved in cancer progression suggests that cyclooxygenase enzymes play an important role in the induction of inflammation, tumor formation, and metastasis of cancer cells. Thus, cyclooxygenase enzymes could be considered for cancer chemotherapy. Among these enzymes, cyclooxygenase 2 (COX-2) is associated with liver carcinogenesis. Various COX-2 inhibitors cause growth inhibition of human hepatocellular carcinoma cells, but many of them act in the COX-2 independent mechanism. Thus, the introduction of selective COX-2 inhibitors is necessary to achieve a clear result. The present study was aimed to determine the growth-inhibitory effects of new analogues of chalcone epoxide as selective COX-2 inhibitors on the human hepatocellular carcinoma (HepG2) cell line. Methods: Estimation of both cell growth and the amount of prostaglandin E2 (PGE2) production were used to study the effect of selective COX-2 inhibitors on the hepatocellular carcinoma cell. Cell growth determination has done by MTT assay in 24 h, 48 h and 72 h, and PGE2 production has estimated by using ELYSA kit in 48 h and 72 h. Results: The results showed growth inhibition of the HepG2 cell line in a concentration and time-dependent manner, as well as a reduction in the formation of PGE2 as a product of COX-2 activity. Among the compounds those analogues with methoxy and hydrogen group showed more inhibitory effect than others. Conclusion: The current in-vitro study indicates that the observed significant growth-inhibitory effect of chalcone-epoxide analogues on the HepG2 cell line may involve COX-dependent mechanisms and the PGE2 pathway parallel to the effect of celecoxib. It can be said that these analogues might be efficient compounds in chemotherapy of COX-2 dependent carcinoma specially preventing and treatment of hepatocellular carcinomas.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.79-87
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• 1989

Enzymatic methylation of arginine and lysine residues of several cytochrome c and lysine residue of calmodulin always resulted in lowering of their respective isoelectric points (pI). Employing cytochromes c derived from various sources, we examined a possible relationship between the degree of amino acid sequence degeneracy and the magnitude of change in the pI values by enzymatic methylation, and found that there was no correlation between these two parameters. By constructing space-filling models of oligopeptide fragments adjacent to the potential methylation sites, we have noted that not all the methylatable residues are able to form hydrogen bonds prior to the methylation. Two preparations of yeast apocytochrome c, one chemically prepared by removing heme from holocytochrome c and the other by translating yeast iso-1-cytochrome c mRNA in vitro, exhibited slightly higher Stokes radii than the homologous holocytochrome c, indicating relatively 'relaxed or open' conformation of the protein. However, when the in vitro synthesized methylated apocytochrome c was compared with the unmethylated counter-part, the Stokes radius of the latter was found to be larger.

• Macromolecular Research
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• v.10 no.5
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• pp.246-252
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• 2002

In order to the development of the delivery device of long-acting local anesthetics for postoperative analgesia and control of chronic pain of cancer patient, fentnyl-loaded poly (L-lactide-co-glycolido) (PLGA, molecular weight, 5,000 g/mole; 50 : 50 mole ratio by lactide to glycolide) microspheres (FMS) were studied. FMS were prepared by an emulsion solvent-evaporation method. The influence of several preparation parameters such as initial drug loading, PLGA concentration, emulsifier concentration, oil phase volume, and fabrication temperature has been investigated on the fentanyl release profiles. Generally, the drug showed the biphasic release patterns, with an initial diffusion followed by a lag period before the onset of the degradation phase, but there was no lag time in our system. Fentanyl was slowly released from FMS over 10 days in vitro with a quasi-zero order property. The release rate increased with increasing drug loading as well as decreasing polymer concentration with relatively small initial burst effect. From the results, FMS may be a good formulation to deliver the anesthetic for the treatment of chronic pain.