sc-236 and Adenocarcinoma

Telomerase activation, which is observed in most human cancers, plays an important role in carcinogenesis. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activity. The aim of the study was to investigate whether nonsteroidal antiinflammatory drugs (NSAIDs) inhibit telomerase activity and hTERT.. Four colon carcinoma cell lines, HT-29, COLO205, CRL-2134, and SW1116, were used in the experiments. Polymerase chain reaction-based telomeric repeat amplification (TRAP) enzyme-linked immunosorbent assay (ELISA) was used to measure telomerase activity in the cells after treatment with aspirin, indomethacin, or SC-236 (a specific cyclooxygenase-2 [COX-2] inhibitor). Expression of hTERT mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The dual luciferase reporter assay was performed to identify the potential cis-response elements to NSAIDs in the promoter region of hTERT.. Aspirin, indomethacin, and SC-236 inhibited telomerase activity in HT-29, COLO205, and CRL-2134 cell lines, but not in the SW1116 cell line. NSAIDs inhibited hTERT mRNA and protein expression through suppression of hTERT transcriptional activity. The hTERT promoter fragment -145 to -330 basepairs (bp) upstream of the ATG starting site was sufficient to respond to the NSAID-induced inhibitory effect and the inhibition was COX-2-independent.. NSAIDs inhibit telomerase activity at hTERT transcriptional, mRNA, and protein levels in colon carcinoma cells. The hTERT promoter fragment -145 to -330 bp may be the cis-response element to NSAIDs.

Topics: Adenocarcinoma; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Blotting, Western; Colonic Neoplasms; Cyclooxygenase 2; Cyclooxygenase Inhibitors; DNA-Binding Proteins; Gene Expression Regulation, Neoplastic; Humans; Indomethacin; Luciferases; Promoter Regions, Genetic; Pyrazoles; Response Elements; RNA, Messenger; RNA, Neoplasm; Sulfonamides; Telomerase; Transcription, Genetic; Tumor Cells, Cultured

Inhibition of cyclooxygenase-2 has been proposed to be a potential mechanism for the chemoprevention of gastrointestinal tumors by nonsteroidal anti-inflammatory drugs. This study investigates the mechanisms by which the cyclooxygenase-2 inhibitor SC236 induces apoptosis of gastric cancer cell lines and its downstream signaling pathway.. Two gastric cancer cell lines, AGS and MKN28, were treated with SC236 and assessed for cell growth and apoptosis. The involvement of mitogen-activated protein kinase and Akt kinase/protein kinase B (Akt/PKB) pathways and their downstream signalings were studied in the AGS cell line.. SC236 treatment induced apoptosis in gastric cancer cells and caused activation of p38 and stress-activated protein kinase/jun kinase, but down-regulated Akt/PKB. The specific p38 inhibitor SB203580 and the dominant-negative stress-activated protein kinase/jun kinase both failed, while the constitutively active form of Akt/PKB was able to block SC236-induced apoptosis. SC236-induced apoptosis was coupled with release of cytochrome c and activation of caspases.. One of the pathways involved in SC-236-induced apoptosis in gastric cancer cells is through downregulation of Akt and then release of cytochrome c.

Topics: Acridine Orange; Adenocarcinoma; Apoptosis; Blotting, Western; Caspases; Cyclooxygenase 2 Inhibitors; Cytochromes c; Down-Regulation; Enzyme Activation; Humans; Mitogen-Activated Protein Kinases; Proto-Oncogene Proteins c-akt; Pyrazoles; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Stomach Neoplasms; Sulfonamides; Transfection; Tumor Cells, Cultured

To investigate the underlying mechanism of apoptosis-inducing effect of a specific COX-2 inhibitor SC236 in gastric cancer cells.. Western blot analysis was used to measure apoptosis-related proteins, cytochrome c, and caspase-3. The catalytic activity of the caspases was measured using a colorimetric assay.. Treatment of AGS gastric cancer cells with SC236 caused a significant elevation of the pro-apoptotic protein Bak, release of cytochrome c to the cytosol, and activation of caspase-3. A specific caspase-3 inhibitor, z-DEVD-fmk, blocked SC236-induced apoptosis.. SC236 inhibits cell growth and induces apoptosis in gastric cancer cells at least partly through the up-regulation of Bak, stimulation of cytochrome c release, and activation of caspase-3.

Topics: Adenocarcinoma; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Caspase 3; Caspases; Cell Line, Tumor; Cyclooxygenase 2 Inhibitors; Cytochromes c; Humans; Oligopeptides; Poly(ADP-ribose) Polymerases; Pyrazoles; Stomach Neoplasms; Sulfonamides

Cyclooxygenase-2 (COX-2) expression is increased in breast cancer and surgery has been shown to increase the growth of metastatic tumours. We investigated the effect of selective COX-2 inhibition on the growth of metastases in either an experimental metastasis model or following excision of a murine primary breast tumour. 50,000 4T1 mammary carcinoma cells were injected into the mammary fat pad of female BALB/c mice. When the mean TD reached 8+/-0.4 mm, tumours were excised and the mice were randomised into two groups (n=12 per group) to receive daily intraperitoneal injections of the selective COX-2 inhibitor, SC-236 or drug vehicle for 14 days. Alternatively, experimental metastases were established by tail-vein injection of 50,000 4T1 cells. Mice received either the selective COX-2 inhibitor, SC-236 or drug vehicle for 14 days (n=12 per group). SC-236 treatment significantly reduced tumour burden, the number and size of spontaneous metastases following primary tumour excision. SC-236 treatment also reduced tumour burden, the number and size of experimental metastases. Immunohistochemical staining demonstrated that COX-2 inhibition reduced microvessel density and increased apoptosis within both spontaneous and experimental metastases. These data clearly demonstrate that the selective COX-2 inhibitor, SC-236, has potent antimetastatic activity against both spontaneous metastases arising following primary tumour excision and experimental metastases.

Topics: Adenocarcinoma; Animals; Apoptosis; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Female; Isoenzymes; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Neovascularization, Pathologic; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Sulfonamides

The effect of selective and non-selective cyclo-oxygenase inhibition on tumour growth and metastasis in an orthotopic model of breast cancer was investigated. 4T1 mammary adenocarcinoma cells were injected into the mammary fat pad of female BALB/c mice. When tumours reached a mean tumour diameter of 8.4+/-0.4 mm, mice were randomised into three groups (n=6 per group) and received daily intraperitoneal injections of the selective cyclo-oxygenase-2 inhibitor, SC-236, the non selective cyclo-oxygenase inhibitor, Indomethacin, or drug vehicle. Tumour diameter was recorded on alternate days. From 8 days after initiation of treatment, tumour diameter in animals treated with either SC-236 or indomethacin was significantly reduced relative to controls. Both primary tumour weight and the number of lung metastases were significantly reduced in the SC-236 and indomethacin treated mice. Microvessel density was reduced and tumor cell apoptosis increased in the primary tumour of mice treated with either the selective or non-selective cyclo-oxygenase inhibitor. In vitro, cyclo-oxygenase inhibition decreased vascular endothelial growth factor production and increased apoptosis of tumour cells. Our results suggest that cyclo-oxygenase inhibitors will be of value in the treatment of both primary and metastatic breast cancer.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Apoptosis; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Drug Screening Assays, Antitumor; Endothelial Growth Factors; Female; Gene Expression Regulation, Neoplastic; Humans; Indomethacin; Isoenzymes; Lung Neoplasms; Lymphokines; Mammary Neoplasms, Experimental; Membrane Proteins; Mice; Mice, Inbred BALB C; Neoplasm Proteins; Neoplasm Transplantation; Neovascularization, Pathologic; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Random Allocation; Substrate Specificity; Sulfonamides; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors