• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.243-251
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• 2006

Dideoxypetrosynol A, a polyacetylene from the marine sponge Petrosia sp., is known to exhibit significant selective cytotoxic activity against a small panel of human tumor cell lines, however, the mechanisms of which are poorly understood. In the present study, it was investigated the further possible mechanisms by which dideoxytetrosynol A exerts its anti-proliferative action in cultured human leukemia cell line U937. We observed that the proliferation-inhibitory effect of dideoxypetrosynol A was due to the induction of G1 arrest of the cell cycle and apoptosis, which effects were associated with up-regulation of cyclin D1 and down-regulation of cyclin E without any change in cyclin-dependent-kinases (Cdks) expression. Dideoxypetrosynol A markedly induced the levels of Cdk inhibitor p16/INK4a expression. Furthermore, down-regulation of phosphorylation of retinoblastoma protein (pRB) by this compound was associated with enhanced binding of pRB and the transcription factor E2F-1. The increase in apoptosis was associated with a dose-dependent up-regulation in pro-apoptotic Bax expression and activation of caspase-3 and caspase-9. Dideoxytetrosynol A decreased the levels of cyclooxygenase (COX)-2 mRNA and protein expression without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E2 (PGE2) synthesis. Furthermore, dideoxytetrosynol A treatment markedly inhibited the activity of telomerase, and the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, was progressively down-regulated by dideoxytetrosynol A treatment in a dose-dependent fashion. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of dideoxytetrosynol A.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3093-3097
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• 2014

Background: Cancer is a major threat to the public health whether in developed or in developing countries. As the most common primary malignant tumor, the morbidity and mortality rate of lung cancer continues to rise in recent ten years worldwide. Chemotherapy is one of the main methods in the treatment of lung cancer, but this is hampered by chemotherapy drug resistance, especially MDR. As a component of the 60S large ribosomal subunit, ribosomal protein L39-L gene was reported to be expressed specifically in the human testis and human cancer samples of various tissue origins. Materials and Methods: Total RNA of cultured drug-resistant and susceptible A549 cells was isolated, and real time quantitative RT-PCR were used to indicate the transcribe difference between amycin resistant and susceptible strain of A549 cells. Viability assay were used to show the amycin resistance difference in RPL39-L transfected A549 cell line than control vector and null-transfected A549 cell line. Results: The ribosomal protein L39-L transcription level was 8.2 times higher in drug-resistant human lung cancer A549 cell line than in susceptible A549 cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells showed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions and Implications for Practice: The ribosomal protein L39-L gene may have effects on the drug resistance mechanism of lung cancer A549 cells.

• Journal of Yeungnam Medical Science
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• v.9 no.1
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• pp.75-89
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• 1992

The development of multi drug-resistant tumor cell population is a major problem in the chemotherapy of human cancer. These cells are often cross resistant to unrelated drugs and the precise mechanisms of multidrug resistant phenotype of tumor cells has not been fully elucidated. Cisplatin resistant tumor cell(SNU-1/$Cis_5$) was induced from human stomach cancer cell line(SNU-1) in vitro. Growth profiles of survival cells were observed during 5 days by thiazolyl blue (MTT) assay. To investigate the cross resistance of various anticancer drugs in SNU-1 and SNU-1/$Cis_5$, We compared the value of $IC_{50}$ - drug concentration at 50% survival of control and gained relative resistances (RR). The RR for SNU-1/$Cis_5$ were as follows; vinblastine, > 43.0 ; epirubicin, 22.9 ; dactinomycin, 16.0 ; etoposide, 15.0 ; vincristine, 9.2 ; adriamycin, 5.7 ; aclarubicin, 5.3. But 5-fluorouracil, methotrexate, daunorubicin have not cross resistance with cisplatin. Resistant inhibition values of $10{\mu}M$ verapamil for SNU-1/$Cis_5$ were as follows; vincristine, 13.1 ; epirubicin, 10.0 ; etoposide, 6.3 ; vinblastine, 4.4 ; dactinomycin, 3.6 ; daunorubicin, 2.4. Membrane proteins of 51,400 and 81,300 daltons were identified by radioiodination with SDS-PAGE, which might represented the drug resistance.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3175-3178
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• 2014

Background: Gastric cancer is a common malignant tumor. Our previous study demonstrated inhibitory effects of 3-bromopyruvate (3-BrPA) on pleural mesothelioma. Moreover, we found that 3-BrPA could inhibit human gastric cancer cell line SGC-7901 proliferation in vitro, but whether similar effects might be exerted in vivo have remained unclear. Aim: To investigate the effect of 3-BrPA to human gastric cancer implant tumors in nude mice. Materials and Methods: Animals were randomly divided into 6 groups: 3-BrPA low, medium and high dose groups, PBS negative control group 1 (PH7.4), control group 2 (PH 6.8-7.8) and positive control group receiving 5-FU. The TUNEL method was used to detect apoptosis, and cell morphology and structural changes of tumor tissue were observed under transmission electron microscopy (TEM). Results: 3-BrPA low, medium, high dose group, and 5-FU group, the tumor volume inhibition rates were 34.5%, 40.2%, 45.1%, 47.3%, tumor volume of experimental group compared with 2 PBS groups (p<0.05), with no significant difference between the high dose and 5-FU groups (p>0.05). TEM showed typical characteristics of apoptosis. TUNEL demonstrated apoptosis indices of 28.7%, 39.7%, 48.7% for the 3-BrPA low, medium, high dose groups, 42.2% for the 5-FU group and 5% and 4.3% for the PBS1 (PH7.4) and PBS2 (PH6.8-7.8) groups. Compared each experimental group with 2 negative control groups, there was significant difference (p<0.05); there was no significant difference between 5-FU group and medium dose group (p>0.05), but there was between the 5-FU and high dose groups (p<0.05). Conclusions: This study indicated that 3-BrPA in vivo has strong inhibitory effects on human gastric cancer implant tumors in nude mice.

• BMB Reports
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• v.39 no.2
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• pp.171-177
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• 2006

Nonsteroidal anti-inflammatory drugs such as indomethacin (IN) can exert anti-colorectal cancer (CRC) activity through cyclooxygenase independent mechanism, but the exactly biological mechanism is not completely known. Here we use proteomic tools to investigate the molecular mechanism of this action. First, nude mice bearing tumors derived from subcutaneous injection with human CRC cell line HCT116 were randomly allocated to groups treated with or without indomethacin. Later, tumor lumps were incised and then total proteins extracted. After separated with two-dimensional electrophoresis, thirty-one differently expressed spots were found between IN-treated and non-IN-treated groups, of which 25 spots decreased and 6 spots increased in abundance in IN-treated group. Through matrix-assisted laser desorption ionization time of flight mass spectrometry and then NCBInr and SWISS-PROT databases searching, 12 protein spots were finally identified including galectin-1, annexin A1, annexin IV, trancription factor BTF3A, calreticulin. Most of the identified proteins are correlated with tumor's biological prosperities of proliferation, invasion, apoptosis and immunity, or take part in cell's signal transduction. From above we thought that indomethacin can exert its effect on colorectal cancer through regulating several proteins' expression directly or indirectly. Further study of these proteins may be helpful in founding new targets of drugs for cancer chemotherapy.

• BMB Reports
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• v.51 no.6
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• pp.296-301
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• 2018

Mitochondrial DNA (mtDNA) mutations are often observed in various cancer types. Although the correlation between mitochondrial dysfunction and cancer malignancy has been demonstrated by several studies, further research is required to elucidate the molecular mechanisms underlying accelerated tumor development and progression due to mitochondrial mutations. We generated an mtDNA-depleted cell line, ${\rho}^0$, via long-term ethidium bromide treatment to define the molecular mechanisms of tumor malignancy induced by mitochondrial dysfunction. Mitochondrial dysfunction in ${\rho}^0$ cells reduced drug-induced cell death and decreased the expression of pro-apoptotic proteins including p53. The p53 expression was reduced by activation of nuclear $factor-{\kappa}B$ that depended on elevated levels of free calcium in $HCT116/{\rho}^0$ cells. Overall, these data provide a novel mechanism for tumor development and drug resistance due to mitochondrial dysfunction.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5463-5468
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• 2014

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

• YAKHAK HOEJI
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• v.48 no.3
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• pp.189-196
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• 2004

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) playa key role in tumor invasion and metastasis. As an inhibitor of MMP-2, TIMP-2 is known to block both the invasive and metastatic behavior of cancer cells, and decrease tumor growth activity. We performed this study to investigate the effects of TIMP-2 over-expression induced by retroviral mediated gene transfer in vitro and in vivo. The human colon cancer cell line SW480 was transfected with the retroviral vector encoding TIMP-2. The effects of TIMP-2 over-expression were analyzed by invasion assay and gelatinase activity test in colon cancer cells and tumorigencity in nude mice. In evaluation of the transfection efficiency of the retroviral vector encoding TIMP-2 in colon cancer cells, we confirmed up-regulation of TIMP-2 expression dependent on the time of cell culture. In addition, inhibition of MMP-2 expression in SW480/TIMP-2 was shown by gelatin zymography. In the in vitro invasion assay SW480/TIMP-2 inhibited the invasiveness on matrigel coated with collagen. To determine whether TIMP-2 can modulate in vivo tumorigenicity and metastasis, SW480/TIMP-2 cells were injected subcutaneously in nude mice. The tumor mass formation of SW480/TIMP-2 cells in nude mice was markedly decreased compared to nontransfected cancer cells. These results showed that colon cancer cells transfected with the retroviral vector encoding TIMP-2 inhibits the invasiveness in vitro and tumorigenicity in vivo.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2837-2840
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• 2012

We investigated whether IFN-${\beta}$ inhibits the growth of human malignant glioma and induces glioma cell apoptosis using the human IFN-${\beta}$ gene transfected into glioma cells. A eukaryonic expression vector ($pSV2IFN{\beta}$) for IFN-${\beta}$ was transfected into the glioma cell line SHG44 using liposome transfection. Stable transfection and IFN-${\beta}$ expression were confirmed using an enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was also assessed by Hoechst staining and electron microscopy. In vivo experiments were used to establish a SHG44 glioma model in nude mice. Liposomes containing the human IFN-${\beta}$ gene were injected into the SHG44 glioma of nude mice to observe glioma growth and calculate tumor size. Fas expression was evaluated using immunohistochemistry. The IFN-${\beta}$ gene was successfully transfected and expressed in the SHG44 glioma cells in vitro. A significant difference in the number of apoptotic cells was observed between transfected and non-transfected cells. Glioma growth in nude mice was inhibited in vivo, with significant induction of apoptosis. Fas expression was also elevated. The IFN-${\beta}$ gene induces apoptosis in glioma cells, possibly through upregulation of Fas. The IFN-${\beta}$ gene modulation in the Fas pathway and apoptosis in glioma cells may be important for the treatment of gliomas.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.490-495
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• 2011

Introduction: Development of carcinoma on oral tongue may cause bilateral cervical lymph node metastasis, rapid invasion and growth of the cancer cells due to rich blood supply in muscle tissues. It is not only difficult to develop an animal experimental model, but also to proceed follow-up research after the development of such model as the induction of cancer lead to difficulty in taking nutrition for the experimental animals that often causes early death. Materials and Methods: IIn this study, author have transplanted YD-$10B_{mod}$ cells into nude mouse oral tongues with different cells number ($5{\times}10^4$, $5{\times}10^5$, $5{\times}10^6$ cells/mouse) and observed the development aspect of oral tongue cancers. Results: The cancer developed from orthotopic transplantation of YD-$10B_{mod}$ cells into nude mouse oral tongue show invasion and central necrosis of the tumor, similar to the cancers developed human oral tongue cancer. The difference in tumor size and the time of central necrosis development depending on the number of transplanted tumor cells shows the feasibility of extending the survival period of the nude mouse by limiting the transplanted tumor cells to < $5{\times}10^4$ cells/mouse or under per nude mouse. Conclusion: This nude mouse model could be used effectively in developing effective chemotheray agent and establishing an animal experimental model that can be used to study the mechanism of cervical lymph node metastasis of the oral tongue cancer.