thiourea and Mouth-Neoplasms

An oral squamous cell carcinoma Ca9-22 cell line was treated with 11-dehydrosinulariolide, an active compound isolated from the soft coral Sinularia leptoclados, in order to evaluate the effect of this compound on cell growth and protein expression. Cell proliferation was strongly inhibited by 11-dehydrosinulariolide treatment. The 2-DE master maps of control and treated Ca9-22 cells were generated by analysis with the PDQuest software. The comparison between such maps showed up- and down-regulation of 23 proteins, of which 14 were upregulated and 9 were downregulated. The proteomic studies described here have identified some proteins, which are involved in the mitochondrial dysfunction and ER-stress pathway and imply that 11-dehydrosinulariolide induces cell apoptosis through either mitochondrial dysfunction-related or ER stress pathway. Based on this observation, several proteins related to apoptosis pathway were explored for the potential roles involved in this drug-induced cytotoxicity. Furthermore, Salubrinal, an ER stress inhibitor, is able to protect the cell from 11-dehydrosinulariolide-induced apoptosis in a physiological dosage. The significance of these studies illustrates the potential development of anticancer drugs from the natural derivatives of soft coral.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cinnamates; Diterpenes; Electrophoresis, Gel, Two-Dimensional; Endoplasmic Reticulum Stress; Humans; Mouth Neoplasms; Proteomics; Thiourea

Diindolylmethane (DIM), an isothiocyanate found in cruciferous vegetables, has been shown to have cancer chemopreventive effects. A series of synthetic C-substituted DIMs (C-DIMs) analogs was developed, including DIM-C-pPhtBu and DIM-C-pPhC6H5, which exhibited better inhibitory activity in cancer cells than DIM. This study examined the effects of C-DIMs on the growth of human oral cancer cells. DIM-C-pPhtBu and DIM-C-pPhC6H5 decreased the number of viable KB cells and induced caspase-dependent apoptosis. The apoptotic cell death was accompanied by a change in Bax/Bcl-2 ratio and damage to mitochondrial membrane potential through the induction of death receptor 5 and the cleavage of Bid and caspase 8. Studies on the mechanism of action showed that the apoptotic cell death induced by DIM-C-pPhtBu and DIM-C-pPhC6H5 was mediated by endoplasmic reticulum stress. In addition, C-DIMs inhibited cell proliferation and induced PARP cleavage through death receptor 5 and CHOP in HEp-2 and HN22 cells. This provides the first evidence that synthetic C-DIMs originating from cruciferous vegetables induce apoptosis in human oral cancer cells through the endoplasmic reticulum stress pathway.

Topics: Anticarcinogenic Agents; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 8; Cell Proliferation; Cinnamates; Endoplasmic Reticulum; Humans; Indoles; Membrane Potential, Mitochondrial; Mouth Neoplasms; Poly(ADP-ribose) Polymerases; PPAR gamma; Receptors, TNF-Related Apoptosis-Inducing Ligand; Thiourea; Transcription Factor CHOP; Tumor Cells, Cultured; Vegetables

The histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), enhances cisplatin [cis-diammine dichloroplatinum (II)] (CDDP)-induced apoptosis in the oral squamous cell carcinoma (OSCC) cell line by complex, multifunctional mechanisms. We investigated the role of endoplasmic reticulum (ER) stress in the enhancing effect of SAHA on CDDP, compared with the ER stressor thapsigargin.. We chose OSCC cell line HSC-3 to ascertain the mechanism of SAHA-enhanced cytotoxicity among various cell lines. HSC-3 cells were incubated with CDDP/SAHA for 48 h, followed by the assessment of cell chemosensitivity to CDDP with MTT and TUNEL assays. Western blot analysis was used to detect the expressions of ER-related molecules, and flow cytometry was used to monitor caspase activity.. Treatment with CDDP/SAHA potently induced apoptosis in HSC-3 cells with a significant increase in caspase-4 and -12 functions. For example, 60% of cells became apoptotic after 48 h of treatment with CDDP/SAHA. In addition, SAHA alone rapidly induced sustained phosphorylation of eukaryotic translation initiation factor-2 (eIF2)alpha, which is up-regulated during ER stress. Inhibition of ER stress by salubrinal, an inhibitor of eIF2alpha dephosphorylation, abrogated SAHA's enhancement of CDDP cytotoxicity. Levels of phospho-Akt are decreased in SAHA-treated cells, and this is in turn associated with increased activity of protein phosphatase 1 (PP1) by SAHA, the phosphatase upstream of Akt.. These data indicate that up-regulation of specific-ER stress-associated events is an integral part of the mechanism by which SAHA enhances CDDP-induced apoptosis, and PP1 up-regulation followed by Akt dephosphorylation plays an important role in SAHA-enhanced CDDP apoptosis.

Topics: Apoptosis; Carcinoma, Squamous Cell; Caspase 12; Caspase Inhibitors; Caspases, Initiator; Cell Line, Tumor; Cinnamates; Cisplatin; Drug Synergism; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Enzyme Inhibitors; Eukaryotic Initiation Factor-2; Female; Heat-Shock Proteins; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; In Situ Nick-End Labeling; Membrane Glycoproteins; Mouth Neoplasms; Phosphorylation; Protein Phosphatase 1; Proto-Oncogene Proteins c-akt; Thapsigargin; Thiourea; Tunicamycin; Valproic Acid; Vorinostat

Topics: Carcinoma; Cell Line; Culture Techniques; Humans; Mouth Neoplasms; Poliovirus; Thiourea