benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone and Mouth-Neoplasms

Resveratrol is known to be an effective chemo-preventive phytochemical against multiple tumor cells. However, the increasing drug resistance avoids the cancer treatment in oral cavity cancer. In this study, we investigated the oral antitumor activity of resveratrol and its mechanism in cisplatin-resistant human oral cancer CAR cells. Our results demonstrated that resveratrol had an extremely low toxicity in normal oral cells and provoked autophagic cell death to form acidic vesicular organelles (AVOs) and autophagic vacuoles in CAR cells by acridine orange (AO) and monodansylcadaverine (MDC) staining. Either DNA fragmentation or DNA condensation occurred in resveratrol-triggered CAR cell apoptosis. These inhibitors of PI3K class III (3-MA) and AMP-activated protein kinase (AMPK) (compound c) suppressed the autophagic vesicle formation, LC3-II protein levels and autophagy induced by resveratrol. The pan-caspase inhibitor Z-VAD-FMK attenuated resveratrol-triggered cleaved caspase-9, cleaved caspase-3 and cell apoptosis. Resveratrol also enhanced phosphorylation of AMPK and regulated autophagy- and pro-apoptosis-related signals in resveratrol-treated CAR cells. Importantly, resveratrol also stimulated the autophagic mRNA gene expression, including Atg5, Atg12, Beclin-1 and LC3-II in CAR cells. Overall, our findings indicate that resveratrol is likely to induce autophagic and apoptotic death in drug-resistant oral cancer cells and might become a new approach for oral cancer treatment in the near future.

Topics: Amino Acid Chloromethyl Ketones; AMP-Activated Protein Kinases; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Autophagy-Related Protein 12; Autophagy-Related Protein 5; Beclin-1; Caspase 3; Caspase 9; Cell Line, Tumor; Cisplatin; DNA Fragmentation; Drug Resistance, Neoplasm; Humans; Microtubule-Associated Proteins; Mouth Neoplasms; Phosphorylation; Proto-Oncogene Proteins c-akt; Resveratrol; RNA, Messenger; Signal Transduction; Stilbenes; TOR Serine-Threonine Kinases

Licochalcone A (Lico-A) is a natural phenol licorice compound with multiple bioactivities, including anti-inflammatory, anti-microbial, anti-fungal and osteogenesis-inducing properties. In the present study, we investigated the Lico-A-induced apoptotic effects and examined the associated apoptosis pathway in KB human oral cancer cells. Lico-A decreased the number of viable KB oral cancer cells. However, Lico-A did not have an effect on primary normal human oral keratinocytes. In addition, the IC50 value of Lico-A was determined to be ~50 µM following dose-dependent stimulation. KB oral cancer cells stimulated with Lico-A for 24 h showed chromatin condensation by DAPI staining, genomic DNA fragmentation by agarose gel electrophoresis and a gradually increased apoptotic cell population by FACS analysis. These data suggest that Lico-A induces apoptosis in KB oral cancer cells. Additionally, Lico‑A‑induced apoptosis in KB oral cancer cells was mediated by the expression of factor associated suicide ligand (FasL) and activated caspase-8 and -3 and poly(ADP-ribose) polymerase (PARP). Furthermore, in the KB oral cancer cells co-stimulation with a caspase inhibitor (Z-VAD-fmk) and Lico-A significantly abolished the apoptotic phenomena. Our findings demonstrated that Lico‑A-induced apoptosis in KB oral cancer cells involves the extrinsic apoptotic signaling pathway, which involves a caspase-dependent FasL-mediated death receptor pathway. Our data suggest that Lico-A be developed as a chemotherapeutic agent for the management of oral cancer.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; Caspase 3; Caspase 8; Caspase Inhibitors; Cell Line, Tumor; Cell Survival; Chalcones; Chromatin; DNA Fragmentation; Extracellular Signal-Regulated MAP Kinases; Fas Ligand Protein; Flavonoids; Humans; Imidazoles; KB Cells; Keratinocytes; Mouth Neoplasms; p38 Mitogen-Activated Protein Kinases; Poly(ADP-ribose) Polymerases; Protein Kinase Inhibitors; Pyridines; Signal Transduction

Ever since protoporphyrin IX (PpIX) was discovered to accumulate preferentially in cancer cells after 5-aminolevulinic acid (ALA) treatment, photodynamic treatment or therapy (PDT) has been developed as an exciting new treatment option for cancer patients. However, the level of PpIX accumulation in oral cancer is fairly low and insufficient for PDT. Ferrochelatase (FECH) and ATP-binding cassette transporter G2 (ABCG2) are known to regulate PpIX accumulation. In addition, serum enhances PpIX export by ABCG2. We investigated here whether and how inhibitors of FECH and ABCG2 and their combination could improve PpIX accumulation and PDT efficacy in an oral cancer cell line in serum-containing medium. ABCG2 inhibitor and the combination of ABCG2 and FECH inhibitors increased PpIX in the presence of fetal bovine serum (FBS) in an oral cancer cell line. Analysis of ABCG2 gene silencing also revealed the involvement of ABCG2 in the regulation of PpIX accumulation. Inhibitors of FECH and ABCG2, and their combination increased the efficiency of ALA-PDT even in the presence of FBS. ALA-PDT-induced cell death was accompanied by apoptotic events and lipid peroxidation. These results suggest that accumulation of PpIX is determined by the activities of ABCG2 and FECH and that treatment with a combination of their inhibitors improves the efficacy of PDT for oral cancer, especially in the presence of serum.

Topics: Amino Acid Chloromethyl Ketones; Aminolevulinic Acid; Apoptosis; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Blood Proteins; Carcinoma, Squamous Cell; Caspase Inhibitors; Cell Line, Tumor; Deferoxamine; Ferrochelatase; Gene Silencing; Humans; Lipid Peroxidation; Mouth Neoplasms; Neoplasm Proteins; Photochemotherapy; Photosensitizing Agents; Protoporphyrins; Siderophores

15-deoxy-Delta(12,14)-prostaglandin J(2) (15-d-PGJ(2)) and troglitazone have been shown to induce apoptosis in several carcinoma cell lines. However, apoptotic signaling pathways of these agents are poorly understood. We tested the hypothesis that peroxisome proliferator-activated receptor-gamma ligands such as these two agents will induce caspase-mediated apoptosis in human oral squamous cell carcinomas (SCC). Treatment of these cell lines with 15-d-PGJ(2) or troglitazone decreased cell viability in a time- and dose-dependent manner. 15-d-PGJ(2), but not troglitazone, induced apoptosis, and this effect was time-dependent. Exposure of cells to 20 micro M of 15-d-PGJ(2) initiated early cytochrome c release, followed by late caspase activation. Furthermore, co-treatment with caspase inhibitors such as Z-VAD-FMK or Z-DEVD-FMK of oral SCC cells that had been treated with 20 micro M of 15-d-PGJ(2) blocked apoptosis. Our study demonstrates that treatment with 15-d-PGJ(2), but not troglitazone, induces apoptosis in human SCC cell lines, and 15-d-PGJ(2) appears to work through cytochrome c release and caspase activation.

Topics: Amino Acid Chloromethyl Ketones; Analysis of Variance; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Caspase Inhibitors; Caspases; Cell Survival; Chromans; Cysteine Proteinase Inhibitors; Cytochrome c Group; Dose-Response Relationship, Drug; Enzyme Activation; Humans; Immunologic Factors; Mouth Neoplasms; Oligopeptides; Prostaglandin D2; Signal Transduction; Thiazoles; Thiazolidinediones; Time Factors; Troglitazone; Tumor Cells, Cultured