naphthoquinones and Tongue-Neoplasms

Deoxyshikonin (DSK), a phytochemical constituent, has been documented to elicit various oncostatic properties alone or in combination with established therapeutics. However, its role in restraining oral squamous cell carcinoma (OSCC) is mostly unclear. Here, we examined the tumor-suppressive effect of DSK and explored the molecular mechanisms underlying DSK's activities on controlling oral cancer. Our results showed that DSK dose-dependently lessened the cell viability of tongue cancer cell lines, involving induction of cell cycle arrest at the sub-G1 phase and apoptotic cell death. Moreover, a unique signature of apoptosis-related proteins, including augmented nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) expression and caspase activation, was observed in DSK-treated tongue cancer cell lines. Furthermore, DSK-mediated upregulation of HO-1 and cleavage of caspase-9 and -3 were significantly inhibited by pharmacological blockage of p38 kinase. Collectively, these data revealed that DSK halted cell cycle progression and elicited cell apoptosis in tongue cancer cell lines, reshaping a p38-dependent profile of apoptotic proteome. Our findings provided novel insights into the therapeutic implications of a natural compound on the management of OSCC.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Carcinoma, Squamous Cell; Cell Line, Tumor; Heme Oxygenase-1; Humans; Mouth Neoplasms; Naphthoquinones; NF-E2-Related Factor 2; p38 Mitogen-Activated Protein Kinases; Tongue Neoplasms

To evaluate the inhibitory effect and mechanism of plumbagin (PLB) against drug-resistant tongue squamous cell carcinoma (TSCC), and whether its antitumour effect is not affected by tumour drug resistance.. TSCC sensitive CAL27 cells and drug-resistant CAL27/RE cells were used to study the cytotoxicity and mechanism of PLB in vitro, including CCK-8 analysis, colony formation, DAPI staining, flow cytometry assay, transmission electron microscopy, western blotting assay, autophagy, apoptosis and ROS fluorescent probes. BALB/c nude mice xenograft models were used to study the growth inhibitory effect of PLB in vivo.. The results showed that the cell viability and proliferation inhibition and apoptosis induction abilities of PLB on drug-resistant cells were more obvious than that on sensitive cells. And PLB induced protective autophagy in TSCC cells. Mechanistically, PLB induced apoptosis and autophagy by generating reactive oxygen species to mediate JNK and AKT/mTOR pathways. Finally, the growth inhibitory effect of PLB against drug-resistant TSCC was also confirmed in vivo.. PLB will be a promising anticancer agent to overcome drug-resistant TSCC without being affected by its drug resistance properties.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Resistance, Neoplasm; Male; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Phytotherapy; Plant Extracts; Tongue; Tongue Neoplasms; TOR Serine-Threonine Kinases

The purpose of this study was to investigate the clinical and histopathological characteristics of GLUT1 in human tongue squamous cell carcinoma (TSCC) and the role of plumbagin (PLB)-mediating GLUT1 in the growth of TSCC.. Forty-five cases of TSCC samples were collected and the expression and location of GLUT1 was analyzed. The role and mechanism of PLB meditating GLUT1 in the inhibitory growth of human TSCC cell line CAL27 were investigated in vitro and vivo.. The expression of GLUT1 was observed in all samples of human TSCC by immunohistochemical staining. GLUT1 expression was significantly correlated with lymph node metastasis and clinical stage in TSCC. PLB treatment decreased cell viability and colony formation, and increased cell apoptosis in association with the downregulation of GLUT1 via inhibiting PI3K/Akt pathway in vitro and PLB suppressed tumor growth in correlation with downregulation of GLUT1, compared with control group in vivo.. The findings demonstrated a novel anti-cancer mechanism of PLB, inhibitory TSCC growth via suppressing PI3K/Akt/GLUT1 pathway, which will supply a theoretical basis for PLB to treat TSCC.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Female; Glucose Transporter Type 1; Humans; Ki-67 Antigen; Male; Matrix Metalloproteinase 2; Mice; Middle Aged; Naphthoquinones; Platelet Endothelial Cell Adhesion Molecule-1; Tongue Neoplasms; Tumor Stem Cell Assay

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone; PLB), a naturally occurring naphthoquinone isolated from the roots of Plumbaginaceae plants, has been reported to possess anticancer activities in both in vitro and in vivo studies, but the effect of PLB on tongue squamous cell carcinoma (TSCC) is not fully understood. This study aimed to investigate the effects of PLB on cell cycle distribution, apoptosis, and autophagy, and the underlying mechanisms in the human TSCC cell line SCC25. The results have revealed that PLB exerted potent inducing effects on cell cycle arrest, apoptosis, and autophagy in SCC25 cells. PLB arrested SCC25 cells at the G2/M phase in a concentration- and time-dependent manner with a decrease in the expression level of cell division cycle protein 2 homolog (Cdc2) and cyclin B1 and increase in the expression level of p21 Waf1/Cip1, p27 Kip1, and p53 in SCC25 cells. PLB markedly induced apoptosis and autophagy in SCC25 cells. PLB decreased the expression of the anti-apoptotic proteins B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xl) while increasing the expression level of the pro-apoptotic protein Bcl-2-associated X protein (Bax) in SCC25 cells. Furthermore, PLB inhibited phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), glycogen synthase kinase 3β (GSK3β), and p38 mitogen-activated protein kinase (p38 MAPK) pathways as indicated by the alteration in the ratio of phosphorylation level over total protein expression level, contributing to the autophagy inducing effect. In addition, we found that wortmannin (a PI3K inhibitor) and SB202190 (a selective inhibitor of p38 MAPK) strikingly enhanced PLB-induced autophagy in SCC25 cells, suggesting the involvement of PI3K- and p38 MAPK-mediated signaling pathways. Moreover, PLB induced intracellular reactive oxygen species (ROS) generation and this effect was attenuated by l-glutathione (GSH) and n-acetyl-l-cysteine (NAC). Taken together, these results indicate that PLB promotes cellular apoptosis and autophagy in TSCC cells involving p38 MAPK- and PI3K/Akt/mTOR-mediated pathways with contribution from the GSK3β and ROS-mediated pathways.

Topics: Apoptosis; Autophagy; Carcinoma, Squamous Cell; Cell Division; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; G2 Phase Cell Cycle Checkpoints; Humans; M Phase Cell Cycle Checkpoints; MAP Kinase Signaling System; Molecular Structure; Naphthoquinones; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Structure-Activity Relationship; Tongue Neoplasms; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Tongue squamous cell carcinoma (TSCC) is the most common malignancy in oral and maxillofacial tumors with highly metastatic characteristics. Plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone; PLB), a natural naphthoquinone derived from the roots of Plumbaginaceae plants, exhibits various bioactivities, including anticancer effects. However, the potential molecular targets and underlying mechanisms of PLB in the treatment of TSCC remain elusive. This study employed stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomic approach to investigate the molecular interactome of PLB in human TSCC cell line SCC25 and elucidate the molecular mechanisms. The proteomic data indicated that PLB inhibited cell proliferation, activated death receptor-mediated apoptotic pathway, remodeled epithelial adherens junctions pathway, and manipulated nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response signaling pathway in SCC25 cells with the involvement of a number of key functional proteins. Furthermore, we verified these protein targets using Western blotting assay. The verification results showed that PLB markedly induced cell cycle arrest at G2/M phase and extrinsic apoptosis, and inhibited epithelial to mesenchymal transition (EMT) and stemness in SCC25 cells. Of note, N-acetyl-l-cysteine (NAC) and l-glutathione (GSH) abolished the effects of PLB on cell cycle arrest, apoptosis induction, EMT inhibition, and stemness attenuation in SCC25 cells. Importantly, PLB suppressed the translocation of Nrf2 from cytosol to nucleus, resulting in an inhibition in the expression of downstream targets. Taken together, these results suggest that PLB may act as a promising anticancer compound via inhibiting Nrf2-mediated oxidative stress signaling pathway in SCC25 cells. This study provides a clue to fully identify the molecular targets and decipher the underlying mechanisms of PLB in the treatment of TSCC.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Line, Tumor; Dose-Response Relationship, Drug; Epithelial-Mesenchymal Transition; G2 Phase Cell Cycle Checkpoints; Head and Neck Neoplasms; Humans; Naphthoquinones; Neoplastic Stem Cells; NF-E2-Related Factor 2; Oxidative Stress; Protein Interaction Maps; Protein Transport; Proteomics; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; Time Factors; Tongue Neoplasms

Plumbagin, a quinonoid constituent isolated from the root of Plumbago zeylanica L., has been proven to possess anti-tumor activity both in vitro and in vivo. However, its anti-tumor properties for human tongue carcinoma have not been reported. This study aimed to investigate the inhibitory effect and the underlying mechanism of plumbagin on the growth of human tongue carcinoma cells.. Cell proliferation ability was detected by EdU incorporation assay and colony formation assay. Cell-cycle distribution was determined by flow cytometric analysis using propidium iodide (PI) staining. Cellular apoptosis was then evaluated by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Western blotting was applied to assay the expression of Bax and Bcl-2.. Plumbagin inhibited the growth and proliferation of Tca8113 cells in vitro in a concentration- and time-dependent manner. The cell cycles of plumbagin-treated Tca8113 cells were arrested at the G2/M phase. Cells treated with plumbagin presented the characteristic morphological changes of apoptosis. The ratio of Bax/Bcl-2 was raised by plumbagin in a concentration-dependent manner.. These results indicate that plumbagin induces the apoptosis of Tca8113 cells through mitochondria-mediated pathway.

Topics: Apoptosis; bcl-2-Associated X Protein; Cell Line, Tumor; Cell Proliferation; Cell Shape; Cell Survival; Deoxyuridine; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; G2 Phase Cell Cycle Checkpoints; Humans; Mitochondria; Mitosis; Naphthoquinones; Signal Transduction; Time Factors; Tongue Neoplasms; Tumor Stem Cell Assay