Flavopiridol Induces Mitochondrial-Mediated Apoptosis in Murine Glioma GL261 Cells via Release of Cytochrome c and Apoptosis Inducing Factor

Newcomb, Elizabeth W.; Tamasdan, Cristina; Entzminger, Yolanda; Alonso, Judith; Friedlander, David R.; Crişan, Diana; Miller, Douglas C.; Zagzag, David

doi:10.4161/cc.2.3.357

Cited by 37 publications

(24 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Flavopiridol can trigger multiple apoptotic pathways depending on the type and stage of the target cell, thus circumventing drug-resistance mechanisms (42)(43)(44). Initial studies demonstrated that flavopiridol induced apoptosis via caspase 8 activation in some tumor cell types (42), whereas more recent evidence indicated that flavopiridol cytotoxic effects involved CytC release in others (33,55,56). Moreover, reports by Alonso et al (44) and Achenbach et al (42) demonstrated that flavopiridol apoptotic activity was exerted independently of both caspase 8 activation and CytC release in a panel of glioma and small-cell lung carcinoma cell lines, suggesting the implication of alternative, unidentified apoptotic mechanisms.…”

Section: Discussionmentioning

confidence: 99%

Induction of Apoptosis by Flavopiridol in Human Neuroblastoma Cells Is Enhanced under Hypoxia and Associated With N-myc Proto-oncogene Down-Regulation

Puppo¹,

Melillo

Pezzolo

et al. 2004

Clinical Cancer Research

View full text Add to dashboard Cite

Purpose: Neuroblastoma is the most common extracranial solid tumor of children that arises from the sympathetic nervous system. Survival rates for neuroblastoma patients is low despite intensive therapeutic intervention, and the identification of new effective drugs remains a primary goal. The cyclin-dependent kinase inhibitor, flavopiridol, has demonstrated growth-inhibitory and cytotoxic activity against various tumor types. Our aim was to investigate flavopiridol effects on advanced-stage, N-myc proto-oncogene (MYCN)-amplified human neuroblastomas and the modulation of its activity by hypoxia, a critical determinant of tumor progression and a major challenge of therapy.Experimental Design: Cell viability was monitored by 3-(4,5 dimethyl-2 thiazolyl)-2,5 diphenyl-2H tetrazolium bromide (MTT) and trypan blue dye exclusion assays; DNA synthesis was assessed with the bromodeoxyuridine pulselabeling technique; apoptosis was studied by Giemsa staining, DNA fragmentation, terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling reaction, flow cytometric determination of hypodiploid DNA content, and evaluation of caspase activity and cytochrome c (CytC) release; MYCN expression was determined by Northern and Western blotting.Results: Flavopiridol caused dose-and time-dependent decreases in neuroblastoma viability by inducing apoptosis, as confirmed by morphologic and biochemical criteria. Cell death was preceded by DNA synthesis inhibition and G 1 -G 2 arrest, reversed by the pancaspase inhibitor, zVAD-fmk, and associated with caspase-3 and -2 activation and CytC increase. Moreover, flavopiridol strongly down-regulated MYCN mRNA and protein expression. Exposure to hypoxia enhanced both the extent of apoptosis and flavopiridol effects on CytC, caspase 3, and MYCN.Conclusions: These results indicate that flavopiridol has growth-inhibitory and apoptotic activity against advancedstage neuroblastomas in vitro and is worthy of further investigation for the treatment of this disease.

show abstract

Section: Discussionmentioning

confidence: 99%

Induction of Apoptosis by Flavopiridol in Human Neuroblastoma Cells Is Enhanced under Hypoxia and Associated With N-myc Proto-oncogene Down-Regulation

Puppo¹,

Melillo

Pezzolo

et al. 2004

Clinical Cancer Research

View full text Add to dashboard Cite

show abstract

“…This agent is also a competitive inhibitor of adenosine triphosphate activity provoking down-expression of Bcl-2, AIF release and caspase-independent PCD. Flavopiridol has demonstrated a potent anti-tumor activity in chronic lymphocytic leukemia and solid tumors (84)(85)(86). A large number of clinical trials using this synthetic flavone are currently in progress.…”

Section: Therapeutic Strategies Targeting Aif-mediated Caspase-indepementioning

confidence: 99%

AIF‐mediated caspase‐independent necroptosis: A new chance for targeted therapeutics

et al. 2011

View full text Add to dashboard Cite

SummaryCell death has been initially divided into apoptosis, in which the cell plays an active role, and necrosis, which is considered a passive cell death program. Intense research performed in the last decades has concluded that ''programmed'' cell death (PCD) is a more complex physiological process than initially thought. Indeed, although in most cases the PCD process is achieved via a family of Cys proteases known as caspases, an important number of regulated PCD pathways do not involve this family of proteases. As a consequence, active forms of PCD are initially referred to as caspase-dependent and caspase-independent. More recent data has revealed that there are also active caspase-independent necrotic pathways defined as necroptosis (programmed necrosis). The existence of necroptotic forms of death was corroborated by the discovery of key executioners such as the kinase RIP1 or the mitochondrial protein apoptosis-inducing factor (AIF). AIF is a Janus protein with a redox activity in the mitochondria and a pro-apoptotic function in the nucleus. We have recently described a particular form of AIF-mediated caspase-independent necroptosis that also implicates other molecules such as PARP-1, calpains, Bax, Bcl-2, histone H2AX, and cyclophilin A. From a therapeutic point of view, the unraveling of this new form of PCD poses a question: is it possible to modulate this necroptotic pathway independently of the classical apoptotic paths? Because the answer is yes, a wider understanding of AIF-mediated necroptosis could theoretically pave the way for the development of new drugs that modulate PCD. To this end, we present here an overview of the current knowledge of AIF and AIF-mediated necroptosis. We also summarize the state of the art in some of the most interesting therapeutic strategies that could target AIF or the AIF-mediated necroptotic pathway.

show abstract

“…Permeabilization of the mitochondria, followed by cytochrome c release has previously been observed for transcriptional inhibitor flavopiridol (Newcomb et al, 2003). For this analysis, we used neuroblastoma cell lines NB-1691 and IMR32 and treated them with either DMSO or 3 mM of ARC.…”

mentioning

confidence: 99%

Proapoptotic compound ARC targets Akt and N-myc in neuroblastoma cells

et al. 2007

View full text Add to dashboard Cite

We have previously described the identification of a nucleoside analog transcriptional inhibitor ARC (4-amino-6-hydrazino-7-b-D-ribofuranosyl-7H-pyrrolo[2,3-d]-pyrimidine-5-carboxamide) that was able to induce apoptosis in cancer cell lines of different origin. Here, we report the characterization of ARC on a panel of neuroblastoma cell lines. We found that these cell lines were more than 10-fold sensitive to ARC than to the well-known nucleoside analog DRB (5,6-dichloro-1-b-Dribofuranosylbenzimidazole), and that ARC-induced apoptosis proceeds through mitochondrial injury. Also, we observed that ARC-mediated cell death was accompanied by caspase-3 cleavage and repression of antiapoptotic proteins such as Mcl-1 and survivin. Conversely, we found that overexpression of Mcl-1-protected neuroblastoma cell line NB-1691 from ARC-induced apoptosis. Furthermore, we found that while ARC inhibited the phosphorylation of Akt Ser-473 in multiple cancer cell lines, forced expression of myristoylated Akt promoted resistance to ARC-induced apoptosis in neuroblastoma cells. In addition, we observed that ARC was able to downregulate the protein levels of N-myc, a commonly amplified oncogene in neuroblastomas, and Akt protected N-myc from ARCinduced downregulation. These data suggest that ARC may antagonize different antiapoptotic pathways and induce apoptosis in neuroblastoma cells via multiple mechanisms. Overall, ARC could represent an attractive candidate for anticancer drug development against neuroblastomas.

show abstract

Flavopiridol Induces Mitochondrial-Mediated Apoptosis in Murine Glioma GL261 Cells via Release of Cytochrome c and Apoptosis Inducing Factor

Cited by 37 publications

References 25 publications

Induction of Apoptosis by Flavopiridol in Human Neuroblastoma Cells Is Enhanced under Hypoxia and Associated With N-myc Proto-oncogene Down-Regulation

Induction of Apoptosis by Flavopiridol in Human Neuroblastoma Cells Is Enhanced under Hypoxia and Associated With N-myc Proto-oncogene Down-Regulation

AIF‐mediated caspase‐independent necroptosis: A new chance for targeted therapeutics

Proapoptotic compound ARC targets Akt and N-myc in neuroblastoma cells

Contact Info

Product

Resources

About