Ismail Adam Arbab

Dentatin Induces Apoptosis in Prostate Cancer Cells via Bcl-2, Bcl-xL, Survivin Downregulation, Caspase-9, -3/7 Activation, and NF-κB Inhibition

This study was set to investigate antiproliferative potential of dentatin (a natural coumarin isolated from Clausena excavata Burm. F) against prostate cancer and to delineate the underlying mechanism of action. Treatment with dentatin dose-dependently inhibited cell growth of PC-3 and LNCaP prostate cancer cell lines, whereas it showed less cytotoxic effects on normal prostate epithelial cell line (RWPE-1). The inhibitory effect of dentatin on prostate cancer cell growth was due to induction of apoptosis as evidenced by Annexin V staining and cell shrinkage. We found that dentatin-mediated accumulation of reactive oxygen species (ROS) and downregulated expression levels of antiapoptotic molecules (Bcl-2, Bcl-xL, and Survivin), leading to disruption of mitochondrial membrane potential (MMP), cell membrane permeability, and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-9, -3/7 activities, and subsequent DNA fragmentation. In addition, we found that dentatin inhibited TNF-α-induced nuclear translocation of p65, suggesting dentatin as a potential NF-κB inhibitor. Thus, we suggest that dentatin may have therapeutic value in prostate cancer treatment worthy of further development.

Dentatin isolated from Clausena excavata induces apoptosis in MCF-7 cells through the intrinsic pathway with involvement of NF-κB signalling and G0/G1 cell cycle arrest: a bioassay-guided approach.

ETHNOPHARMACOLOGICAL RELEVANCE Clausena excavata Burm. f. has been used in folk medicines in eastern Thailand for the treatment of cancer. MATERIALS AND METHODS To investigate the apoptosis mechanism, we isolated dentatin (DTN) from this plant using a bioassay-guided approach. DTN-induced cytotoxicity was observed with the MTT assay. Acridine orange/propidium iodide staining was used to detect cells in early apoptosis and high content screening (HCS) to observe nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and cytochrome c release. Apoptosis was confirmed with a clonogenic assay, DNA laddering and caspase 3/7 and 9 assays. Reactive oxygen species (ROS) formation, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. The involvement of nuclear factor-kappa B (NF-κB) was analysed with the HCS assay. RESULTS A significant increase in chromatin condensation in the cell nucleus was observed by fluorescence analysis. Apoptosis was confirmed by the reduced number of colonies in the clonogenic assay and the increased number of cellular DNA breaks in treated cells observed as a DNA ladder. Treatment of MCF-7 cells with DTN encouraged apoptosis with cell death-transducing signals that reduced MMP by down-regulation of Bcl-2 and up-regulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase 9 followed by the executioner caspase 3/7. DTN treatment significantly arrested MCF-7 cells at the G0/G1 phase (p<0.05) and ROS was significantly elevated. Moreover, DTN significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus. CONCLUSION Together, the results demonstrated that the DTN isolated from Clausena excavata inhibited the proliferation of MCF-7 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to occur through the mitochondrial pathway with involvement of the NF-κB signalling pathway.

Induction of apoptosis in cancer cells by NiZn ferrite nanoparticles through mitochondrial cytochrome C release

The long-term objective of the present study was to determine the ability of NiZn ferrite nanoparticles to kill cancer cells. NiZn ferrite nanoparticle suspensions were found to have an average hydrodynamic diameter, polydispersity index, and zeta potential of 254.2 ± 29.8 nm, 0.524 ± 0.013, and −60 ± 14 mV, respectively. We showed that NiZn ferrite nanoparticles had selective toxicity towards MCF-7, HepG2, and HT29 cells, with a lesser effect on normal MCF 10A cells. The quantity of Bcl-2, Bax, p53, and cytochrome C in the cell lines mentioned above was determined by colorimetric methods in order to clarify the mechanism of action of NiZn ferrite nanoparticles in the killing of cancer cells. Our results indicate that NiZn ferrite nanoparticles promote apoptosis in cancer cells via caspase-3 and caspase-9, downregulation of Bcl-2, and upregulation of Bax and p53, with cytochrome C translocation. There was a concomitant collapse of the mitochondrial membrane potential in these cancer cells when treated with NiZn ferrite nanoparticles. This study shows that NiZn ferrite nanoparticles induce glutathione depletion in cancer cells, which results in increased production of reactive oxygen species and eventually, death of cancer cells.

Inclusion Complex of Zerumbone with Hydroxypropyl-β-Cyclodextrin Induces Apoptosis in Liver Hepatocellular HepG2 Cells via Caspase 8/BID Cleavage Switch and Modulating Bcl2/Bax Ratio

Zerumbone (ZER) isolated from Zingiber zerumbet was previously encapsulated with hydroxypropyl-β-cyclodextrin (HPβCD) to enhance ZERs solubility in water, thus making it highly tolerable in the human body. The anticancer effects of this new ZER-HPβCD inclusion complex via apoptosis cell death were assessed in this study for the first time in liver hepatocellular cells, HepG2. Apoptosis was ascertained by morphological study, nuclear stain, and sub-G1 cell population accumulation with G2/M arrest. Further investigations showed the release of cytochrome c and loss of mitochondrial membrane potential, proving mitochondrial dysfunction upon the ZER-HPβCD treatment as well as modulating proapoptotic and anti-apototic Bcl-2 family members. A significant increase in caspase 3/7, caspase 9, and caspase 8 was detected with the depletion of BID cleaved by caspase 8. Collectively, these results prove that a highly soluble inclusion complex of ZER-HPβCD could be a promising anticancer agent for the treatment of hepatocellular carcinoma in humans.

α-Mangostin from Cratoxylum arborescens demonstrates apoptogenesis in MCF-7 with regulation of NF-κB and Hsp70 protein modulation in vitro, and tumor reduction in vivo.

Cratoxylum arborescens is an equatorial plant belonging to the family Guttiferae. In the current study, α-Mangostin (AM) was isolated and its cell death mechanism was studied. HCS was undertaken to detect the nuclear condensation, mitochondrial membrane potential, cell permeability, and the release of cytochrome c. An investigation for reactive oxygen species formation was conducted using fluorescent analysis. To determine the mechanism of cell death, human apoptosis proteome profiler assay was conducted. In addition, using immunofluorescence and immunoblotting, the levels of Bcl-2-associated X protein (Bax) and B-cell lymphoma (Bcl)-2 proteins were also tested. Caspaces such as 3/7, 8, and 9 were assessed during treatment. Using HCS and Western blot, the contribution of nuclear factor kappa-B (NF-κB) was investigated. AM had showed a selective cytotoxicity toward the cancer cells with no toxicity toward the normal cells even at 30 μg/mL, thereby indicating that AM has the attributes to induce cell death in tumor cells. The treatment of MCF-7 cells with AM prompted apoptosis with cell death-transducing signals. This regulated the mitochondrial membrane potential by down-regulation of Bcl-2 and up-regulation of Bax, thereby causing the release of cytochrome c from the mitochondria into the cytosol. The liberation of cytochrome c activated caspace-9, which, in turn, activated the downstream executioner caspace-3/7 with the cleaved poly (ADP-ribose) polymerase protein, thereby leading to apoptotic alterations. Increase of caspace 8 had showed the involvement of an extrinsic pathway. This type of apoptosis was suggested to occur through both extrinsic and intrinsic pathways and prevention of translocation of NF-κB from the cytoplasm to the nucleus. Our results revealed AM prompt apoptosis of MCF-7 cells through NF-κB, Bax/Bcl-2 and heat shock protein 70 modulation with the contribution of caspaces. Moreover, ingestion of AM at (30 and 60 mg/kg) significantly reduced tumor size in an animal model of breast cancer. Our results suggest that AM is a potentially useful agent for the treatment of breast cancer.

Clausena excavata Burm. f. (Rutaceae): A review of its traditional uses, pharmacological and phytochemical properties

The present review describes the morphological, traditional, phytochemical and pharmacological aspects of Clausena excavata ( Burm. f., Rutaceae). The plant grows wild in the tropical and subtropical parts of Asia and represents one of the richest sources of medicinal natural products. It is intensively used currently in traditional medicine for treatment of different illnesses. One part or a mixture of two or more parts of the plant in the form of powder or liquid doze is usually given to the patient. Phytochemically, many pure compounds from several secondary metabolite groups of C. excavata have been isolated from different parts of the plant including leaves, stems, stem barks, roots, root barks, rhizomes and flowers. Their chemical structures however, have been elucidated using several spectroscopic techniques. Pharmacologically, many secondary metabolites including alkaloids and coumarins have been tested for their biological activities. Anticancer, immunomodulatory, anti-HIV-1, antioxidant, antibacterialial, insecticidal, antifungal, antinociceptive, anti-malarial and antiplatelet activities of this plant have been detailed here. This paper enumerates an overview of its phytochemical and pharmacological properties, which may provide assistance to researchers to determine further, the efficacy and potency of C. excavata as medicinal plant.

Dentatin from Clausena excavata Induces Apoptosis in HepG2 Cells via Mitochondrial Mediated Signaling.

Hepatocellular carcinoma (HCC) is a primary liver cancer with high global incidence and mortality rates. Current candidate drugs to treat HCC remain lacking and those in use possess undesirable side effects. In this investigation, the antiproliferative effects of dentatin (DTN), a natural coumarin, were evaluated on HepG2 cells and DTNs probable preliminary molecular mechanisms in apoptosis induction were further investigated. DTN significantly (p<0.05) suppressed proliferation of HepG2 cells with an IC50 value of 12.0 μg/mL, without affecting human normal liver cells, WRL-68 (IC50>50 μg/mL) causing G0/G1 cell cycle arrest via apoptosis induction. Caspase colorimetric assays showed markedly increased levels of caspase-3 and caspase-9 activities throughout the treatment period. Western blotting of treated HepG2 cells revealed inhibition of NF-κB that triggers the mitochondrial-mediated apoptotic signaling pathway by up-regulating cytoplasmic cytochrome c and Bax, and down-regulating Bcl-2 and Bcl-xL. The current findings suggest DTN has the potential to be developed further as an anticancer compound targeting human HCC.

Anti-ulcerogenic activity of dentatin from Clausena excavata Burm.f. against ethanol-induced gastric ulcer in rats: possible role of mucus and anti-oxidant effect

BACKGROUND Clausena excavata Burm.f. (Rutaceae) has been used for the treatment of stomach disorders including peptic ulcer. PURPOSE In this study, we aimed to investigate dentatin isolated from C. excavata Burm.f., for anti-ulcer activity against ethanol ulcer model in rats. METHODS Gastric acid output, ulcer index, serum profile, histological evaluation using Hematoxylin and eosin (HE), periodic acid Schiff base stainings and immunohistochemical localization for heat shock proteins 70 (HSP70) were all investigated. Possible involvement of reduced glutathione (GSH), lipid peroxidation, prostaglandin E2 (PGE2), superoxide dismutase (SOD) enzymes, radical scavenging, and anti-Helicobacter pylori activity were investigated. RESULTS Dentatin showed anti-secretory activity against the pylorus ligature model and protected the gastric mucosa from ethanol ulceration, as revealed by the improved macroscopic and histological appearance. Dentatin significantly increased the gastric homogenate content of PGE2 GSH and SOD. Dentatin inhibited the lipid peroxidation as revealed by the reduced gastric content of malondialdehyde (MDA). Moreover, dentatin up-regulated HSP70 expression. However, dentatin showed insignificant anti-H. pylori activity. CONCLUSION Dentatin possesses gastro-protective activity, which could be attributed to the anti-secretory, mucus production, anti-oxidant, and HSP70 activities.

Dentatin induces apoptosis in PC3 and LNCaP prostate cancer cells via Bcl- 2, Bcl-xL, Survivin downregulation, Caspase-9, −3/7 activation, and NF-κB inhibition

Abstract Introduction Prostate cancer is one of the major causes of deaths in men worldwide with considerable rate due to progressive behavior of androgen-independent cells which become insensitive to hormone ablation therapy. Researchers are in continuous and serious efforts to discover new anticancer drugs as recent therapeutic regimens sometimes ineffective against prostate cancer. Medicinal plants are considered one of the hopeful options providing new bioactive compounds for the treatment of cancer. Objective This study was established to demonstrate antiproliferative prospect of dentatin, the natural secondary metabolite belongs to coumarins against prostate cancer and to investigate the underlying mechanism of apoptosis. Methods Treatment with dentatin inhibited cell growth of PC-3 and LNCaP prostate cancer cell lines dose-dependently, whereas it exerted less cytotoxic effects on normal prostate epithelial cell line (RWPE-1). The inhibitory effect of dentatin on prostate cancer cell growth was due to induction of apoptosis as manifested by Annexin V staining and cell shrinkage. Results & Discussion We found that dentatin-mediated aggregation of reactive oxygen species (ROS) and downregulated expression levels of antiapoptotic molecules (Bcl-2, Bcl-xL, and Survivin), leading to disruption of mitochondrial membrane potential (MMP), cell membrane permeability, and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-9, −3/7 activities, and subsequent DNA fragmentation. Moreover, we found that dentatin inhibited TNF-α-induced nuclear translocation of p65, suggesting dentatin as a potential NF-κB inhibitor. Conclusion Therefore, we propose that dentatin may have therapeutic value in prostate cancer treatment worthy of further development.

Dentatin Isolated from Clausena Excavata Induces Apoptosis in MCF-7, PC-3 and LNCaP Cells: an Evaluation by the Bioactivity Assay GuidedFractionation

UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, University Putra Malaysia, Serdang, Selangor, Malaysia; Department of Chemistry, Faculty of Science, University Putra Malaysia, Serdang, Selangor, Malaysia; Department of Veterinary Pathology and Microbiology, Faculty of Veterinary, University Putra Malaysia, Serdang, Selangor, Malaysia; Department of Microbiology, Faculty of Veterinary Science, University of Nyala, Nyala, Sudan; Department of Pharmacy, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; Medical Research Centre, Jazan University, P.O. Box 114 Jazan, Kingdom of Saudi Arabia; E-mails: arbabismailadam@yahoo.com; ismailupm2011@gmail.com