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ABSTRACT: Andrographolide is a diterpenoid lactone isolated from Andrographis paniculata (King of Bitters), an herbal medicine used in Asia. It has been reported to have anti-inflammatory, antihypertensive, antiviral, and immune-stimulant properties. Furthermore, it has been shown to inhibit cancer cell proliferation and induce apoptosis in leukemia and solid tumor cell lines.
We studied the Burkitt p53-mutated Ramos cell line, the mantle cell lymphoma (MCL) line Granta, the follicular lymphoma (FL) cell line HF-1, and the diffuse large B-cell lymphoma (DLBCL) cell line SUDHL4, as well as primary cells from patients with FL, DLBCL, and MCL.
We found that andrographolide resulted in dose- and time-dependent cell death as measured by MTT. Andrographolide significantly increased reactive oxygen species (ROS) production in all cell lines. To determine mechanism of cell death, we measured apoptosis by Annexin V/propidium iodide in the presence and absence of the antioxidant N-acetyl-l-cysteine (NAC), the glutathione (GSH)-depleting agent buthionine sulfoxamine (BSO), or caspase inhibitors. We found that apoptosis was greatly enhanced by BSO, blocked by NAC, and accompanied by poly(ADP-ribose) polymerase cleavage and activation of caspase-3, caspase-8, and caspase-9. We measured BAX conformational change and mitochondrial membrane potential, and using mouse embryonic fibroblast (MEF) Bax/Bak double knockouts (MEF(Bax-/-/Bak-/-)), we found that apoptosis was mediated through mitochondrial pathways, but dependent on caspases in both cell lines and patient samples.
Andrographolide caused ROS-dependent apoptosis in lymphoma cell lines and in primary tumor samples, which was enhanced by depletion of GSH and inhibited by NAC or the pan-caspase inhibitor Z-VAD-FMK. Further studies of diterpenoid lactones in lymphoma are warranted.
Clinical Cancer Research 10/2010; 16(19):4755-68. · 7.74 Impact Factor
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Savita Bhalla,
Leo I Gordon, Kevin David,
Sheila Prachand,
Amareshwar T K Singh,
Shuo Yang,
Jane N Winter,
Dongsheng Guo,
Thomas O'Halloran,
Leonidas C Platanias,
Andrew M Evens
British Journal of Haematology 08/2010; 150(3):365-9. · 4.94 Impact Factor
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Sonali Joshi,
Surinder Kaur,
Amanda J Redig,
Katy Goldsborough, Kevin David,
Takeshi Ueda,
Rie Watanabe-Fukunaga,
Darren P Baker,
Eleanor N Fish,
Rikiro Fukunaga,
Leonidas C Platanias
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ABSTRACT: We provide evidence for the existence of an IFN-regulated cellular pathway involving the mitogen-activated protein kinase (MAPK)-integrating kinase (Mnk) 1. Our data demonstrate that type I (alpha, beta) IFNs induce phosphorylation/activation of Mnk1, which, in turn, regulates phosphorylation of the eukaryotic initiation factor 4E (eIF4E) on Ser-209. Such Mnk activation depends on upstream engagement of Jak1, and requires downstream activation of the Mek/Erk MAPK pathway. In studies using double Mnk1-/-Mnk2-/- knockout mouse embryonic fibroblasts (MEFs), we found that engagement of Mnk kinases is essential for mRNA translation of the Isg15 and Isg54 genes, suggesting an important role for this pathway in mRNA translation of IFN-stimulated genes (ISGs). Importantly, our data demonstrate that pharmacological inhibition of Mnk kinases or siRNA-mediated knockdown of Mnk1 and Mnk2 results in partial reversal of the suppressive effects of IFNalpha on normal and leukemic hematopoietic progenitors, establishing a key role for this pathway in the generation of the growth inhibitory effects of type I IFNs. Together, our findings establish that the Mnk/eIF4E kinase pathway is activated in an IFN-inducible manner and plays important roles in mRNA translation for ISGs and generation of IFN-inducible anti-proliferative responses.
Proceedings of the National Academy of Sciences 08/2009; 106(29):12097-102. · 9.68 Impact Factor
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ABSTRACT: We investigated the cytotoxicity and mechanisms of cell death of the broad-spectrum histone deacetylase (HDAC) inhibitor PCI-24781, alone and combined with bortezomib in Hodgkin lymphoma and non-Hodgkin lymphoma cell lines and primary lymphoproliferative (CLL/SLL) cells.
Apoptosis, mitochondrial membrane potential, cell cycle analysis, and reactive oxygen species (ROS) were measured by flow cytometry, whereas caspase activation was determined by Western blot. Nuclear factor kappaB (NF-kappaB)-related mRNAs were quantified by reverse transcription-PCR, NF-kappaB-related proteins by Western blotting, and NF-kappaB DNA-binding activity by electromobility shift assay. Finally, gene expression profiling was analyzed.
PCI-24781 induced concentration-dependent apoptosis that was associated with prominent G(0)/G(1) arrest, decreased S-phase, increased p21 protein, and increased ROS in Hodgkin lymphoma and non-Hodgkin lymphoma cell lines. Dose-dependent apoptosis with PCI-24781 was also seen among primary CLL/SLL cells. PCI-24781-induced apoptosis was shown to be ROS- and caspase-dependent. Combined PCI-24781/bortezomib treatment resulted in strong synergistic apoptosis in all non-Hodgkin lymphoma lines (combination indices, 0.19-0.6) and was additive in Hodgkin lymphoma and primary CLL/SLL cells. Further, PCI-24781/bortezomib resulted in increased caspase cleavage, mitochondrial depolarization, and histone acetylation compared with either agent alone. Gene expression profiling showed that PCI-24781 alone significantly down-regulated several antioxidant genes, proteasome components, and NF-kappaB pathway genes, effects that were enhanced further with bortezomib. Reverse transcription-PCR confirmed down-regulation of NF-kappaB1 (p105), c-Myc, and IkappaB-kinase subunits, where NF-kappaB DNA binding activity was decreased.
We show that PCI-24781 results in increased ROS and NF-kappaB inhibition, leading to caspase-dependent apoptosis. We also show that bortezomib is synergistic with PCI-24781. This combination or PCI-24781 alone has potential therapeutic value in lymphoma.
Clinical Cancer Research 06/2009; 15(10):3354-65. · 7.74 Impact Factor
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ABSTRACT: We investigated the cytotoxicity and biology of the novel broad-spectrum hydroxamic acid-based histone deacetylase inhibitor (HDACi), PCI-24781. PCI-24781 was studied alone and combined with bortezomib in Hodgkin lymphoma (L428) and non-Hodgkin's lymphoma cell lines (Ramos, HF1, SUDHL4). PCI-24781 induced dose-dependent apoptosis that was associated with prominent G0/G1 arrest, decreased S-phase, increased p21 protein expression, and production of reactive oxygen species (ROS). Furthermore, PCI-24781-induced apoptosis was shown to be ROS- and caspase-dependent. Combined PCI-24781 and bortezomib exposure resulted in strong synergistic apoptosis in all cell lines (combination indices 0.19-0.6). Furthermore, compared to either agent alone, PCI-24781/bortezomib resulted in increased caspase cleavage, mitochondrial depolarization, and histone hyperacetylation. Microarray analyses showed that PCI-24781 alone significantly downregulated several antioxidant genes, proteasome components, and NF-kappaB pathway genes, effects which were enhanced further with bortezomib. RT-PCR confirmed downregulation of NF-kappaB targets NF-kappaB1 (p105), c-Myc, and IkappaB-kinase subunits, while gel-shift showed decreased NF-kappaB DNA-binding activity. Taken together, these results suggest that increased oxidative stress and NF-kappaB inhibition, leading to caspase activation and apoptosis, are likely responsible for the activity of PCI-24781 as well as the observed synergy with bortezomib. These data indicate that PCI-24781 has potential therapeutic value in lymphoma as a single-agent and combined with bortezomib.
Nature Precedings.
