Indirubin-3-monooxime induced cell cycle arrest and apoptosis in Hep-2 human laryngeal carcinoma cells
The commercially available analogue of indirubin, indirubin-3-oxime, is known for its antitumor activities. To further establish its role in anticancer activity, we tested its potential against human laryngeal carcinoma cell line (Hep-2). We investigated the molecular mechanisms of indirubin-induced apoptosis and growth arrest in human laryngeal carcinoma cells. Upon treatment with indirubin-3-monooxime, a time dependent inhibition of cell growth was observed and cells developed many hallmark features of apoptosis. The increase of chromatin condensation after treatment with indirubin-3-oxime identified by staining with chromatin stain Hoechst 333258 indicates apoptosis. The observed increase in DNA fragmentation after indirubin-3-oxime in DNA gel electrophoresis indicates the apoptotic feature exhibited by the drug. Flow cytometric analysis confirmed that indirubin increased populations of apoptotic phase G1. Indirubin-3-oxime-induced growth inhibition was associated with induction of Cdk inhibitor p21, inhibition of cyclin D1 and activation of caspase-3. We conclude that indirubin-3-oxime induces cell death and apoptosis in human laryngeal carcinoma cells.
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Available from: Yaohong Tan
- "Resistance to cell cycle arrest is another way P-gp helps MDR cancer cells survive the conventional chemo-agents . Previous studies have demonstrated that certain indirubin derivatives are capable of inducing cell cycle arrest in cancer cells –. Our data indicate that PH II-7 substantially inhibited the cell cycles of not only K562 but also K562/A02 cells in S phase (Fig. 5A,B). Physiologically, by ensuring that the onset of mitosis is dependent on the completion of DNA replication, the S phase checkpoint prevents the generation of aneuploid daughter cells that are not viable. "
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ABSTRACT: Multidrug resistance mediated by P-glycoprotein in cancer cells has been a major issue that cripples the efficacy of chemotherapy agents. Aimed for improved efficacy against resistant cancer cells, we designed and synthesized 25 oxindole derivatives based on indirubin by structure-activity relationship analysis. The most potent one was named PH II-7, which was effective against 18 cancer cell lines and 5 resistant cell lines in MTT assay. It also significantly inhibited the resistant xenograft tumor growth in mouse model. In cell cycle assay and apoptosis assay conducted with flow cytometry, PH II-7 induced S phase cell cycle arrest and apoptosis even in resistant cells. Consistently revealed by real-time PCR, it modulates the expression of genes related to the cell cycle and apoptosis in these cells, which may contributes to its efficacy against them. By side-chain modification and FITC-labeling of PH II-7, we were able to show with confocal microscopy that not only it was not pumped by P-glycoprotein, it also attenuated the efflux of Adriamycin by P-glycoprotein in MDR tumor cells. Real-time PCR and western blot analysis showed that PH II-7 down-regulated MDR1 gene via protein kinase C alpha (PKCA) pathway, with c-FOS and c-JUN as possible mediators. Taken together, PH II-7 is a dual-functional compound that features both the cytotoxicity against cancer cells and the inhibitory effect on P-gp mediated drug efflux.
Available from: John A Beutler
- "Indirubin-3′-oxime was synthesized with a condensation reaction between hydroxylamine and indirubin, an indole-type alkaloid that could be easily isolated from the leaves of several plants, such as Polygonum tinctorium (Polygonaceae), Isatis indigotica (Brassicaceae), Indigofera suffruticosa (Fabaceae), Indigofera tinctoria (Fabaceae), and Strobilanthes cusia (Acanthaceae) (Cuong et al., 2010a,b). Recently, indirubin-3′-oxime was found to induce cell cycle arrest and apoptosis in Hep-2 human laryngeal carcinoma cells (Kameswaran and Ramanibai, 2009). In the effects on RNase H activity , indirubin-3′-oxime exhibited inhibition of 82% at the concentration of 50 μg/mL. "
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ABSTRACT: Acquired immune deficiency syndrome (AIDS) is a severe pandemic disease especially prevalent in poor and developing countries. Thus, developing specific, potent antiviral drugs that restrain infection by human immunodeficiency virus type 1 (HIV-1), a major cause of AIDS, remains an urgent priority.
This study evaluated 32 extracts and 23 compounds from Vietnamese medicinal plants for their inhibitory effects against HIV-1 ribonuclease H (RNase H) and their role in reversing the cytopathic effects of HIV.
The plants were air-dried and extracted in different solvent systems to produce plant extracts. Natural compounds were obtained as previously published. Samples were screened for RNase H inhibition followed by a cytopathic assay. Data were analyzed using the Microsoft Excel.
At 50 μg/mL, 11 plant extracts and five compounds inhibited over 90% of RNase H enzymatic activity. Methanol extracts from Phyllanthus reticulatus and Aglaia aphanamixis leaves inhibited RNase H activity by 99 and 98%, respectively, whereas four extracts showed modest protection against the cytopathic effects of HIV.
The screening results demonstrated that the butanol (BuOH) extract of Celastrus orbiculata leaves, methanol (MeOH) extracts of Glycosmis stenocarpa stems, Eurya ciliata leaves, and especially P. reticulatus leaves showed potential RNase H inhibition and protection against the viral cytopathic effects of HIV-1. Further chemical investigations should be carried out to find the active components of these extracts and compounds as potential anti-HIV drug candidates.
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ABSTRACT: 5'-Nitro-indirubinoxime (5'-NIO) is a derivative of the bis-indole indirubin that exhibits anticancer activities. The present study investigated the anti-invasive action of 5'-NIO in salivary gland ductal adenocarcinoma, SGT cells.
The wound-scratch, migration, and invasion assays were applied to determine the effect of 5'-NIO on the migration capacity and invasiveness of SGT cells. Reverse-transcriptase-polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate the impacts of 5'-NIO on the expression of beta1 integrin and matrix metalloproteinases MMP-2 (gelatinase-A) and MMP-9 (gelatinase-B).
The viability of SGT cells was decreased by 5'-NIO in a dose-dependent manner, but not significant at the concentrations of 0.5 and 1 microM. Under the concentrations showing little cytotoxic effect, 5'-NIO exhibited a dose-dependent inhibitory effect on the invasion and migration of SGT cells. Furthermore, 5'-NIO suppressed the mRNA and protein expression of beta1 integrin and MMP-2 and MMP-9.
Taken together, these results suggest that 5'-NIO, even at low concentrations, may effectively inhibit the invasion and migration of SGT cells by suppressing beta1 integrin-mediated signaling.
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