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Adaptive mitochondrial reprogramming and resistance to PI3K therapy

BACKGROUND: Small molecule inhibitors of phosphatidylinositol-3 kinase (PI3K) have been developed as molecular therapy for cancer, but their efficacy in the clinic is modest, hampered by resistance mechanisms.METHODS: We studied the effect of PI3K therapy in patient-derived tumor organotypic cultures (from five patient samples), three glioblastoma (GBM) tumor cell lines, and an intracranial model

Deletion of the mitochondrial chaperone TRAP-1 uncovers global reprogramming of metabolic networks

Reprogramming of metabolic pathways contributes to human disease, especially cancer, but the regulators of this process are unknown. Here, we have generated a mouse knockout for the mitochondrial chaperone TRAP-1, a regulator of bioenergetics in tumors. TRAP-1(-/-) mice are viable and showed reduced incidence of age-associated pathologies, including obesity, inflammatory tissue degeneration, dyspl

DNA-PK inhibition by NU7441 sensitizes breast cancer cells to ionizing radiation and doxorubicin

DNA-dependent protein kinase (DNA-PK) plays a key role in the repair of DNA double-strand breaks (DSBs) that are probably the most deleterious form of DNA damage. Inhibition of DNA-PK has been considered as an attractive approach to decrease resistance to therapeutically induced DNA DSBs. Ionizing radiation (IR) and doxorubicin, which induce DSBs, are used in the treatment of breast cancer. We det

Cyclophilin D extramitochondrial signaling controls cell cycle progression and chemokine-directed cell motility

Mitochondria control bioenergetics and cell fate decisions, but how they influence nuclear gene expression is understood poorly. Here, we show that deletion or reduction in the levels of cyclophilin D (CypD, also called Ppif), a mitochondrial matrix peptidyl prolyl isomerase and apoptosis regulator, results in increased cell proliferation and enhanced cell migration and invasion. These responses a

Chk2 phosphorylation of survivin-DeltaEx3 contributes to a DNA damage-sensing checkpoint in cancer

Survivin is an oncogene that functions in cancer cell cytoprotection and mitosis. Here we report that differential expression in cancer cells of a C-terminal splice variant of survivin, termed survivin-ΔEx3, is tightly associated with aggressive disease and markers of unfavorable prognosis. In contrast to other survivin variants, survivin-ΔEx3 localized exclusively to nuclei in tumor cells and was

Chemosensitization of cancer cells by KU-0060648, a dual inhibitor of DNA-PK and PI-3K

DNA double-strand breaks (DSB) are the most cytotoxic lesions induced by topoisomerase II poisons. Nonhomologous end joining (NHEJ) is a major pathway for DSB repair and requires DNA-dependent protein kinase (DNA-PK) activity. DNA-PK catalytic subunit (DNA-PKcs) is structurally similar to PI-3K, which promotes cell survival and proliferation and is upregulated in many cancers. KU-0060648 is a dual

Further characterisation of the cellular activity of the DNA-PK inhibitor, NU7441, reveals potential cross-talk with homologous recombination

PURPOSE: Inhibition of DNA repair is emerging as a new therapeutic strategy for cancer treatment. One promising target is DNA-PK, a pivotal kinase in double-strand break repair. The purpose of this study was to further characterise the activity of the DNA-PK inhibitor NU7441, giving some new insights into the biology of DNA-PK.METHODS: We used NU7441, a potent DNA-PK inhibitor, to evaluate potenti

Targeted inhibition of mitochondrial Hsp90 suppresses localised and metastatic prostate cancer growth in a genetic mouse model of disease

BACKGROUND: The molecular chaperone heat shock protein-90 (Hsp90) is a promising cancer drug target, but current Hsp90-based therapy has so far shown limited activity in the clinic.METHODS: We tested the efficacy of a novel mitochondrial-targeted, small-molecule Hsp90 inhibitor, Gamitrinib (GA mitochondrial matrix inhibitor), in the Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model. Th

Antitumor and anti-inflammatory effects of trabectedin on human myxoid liposarcoma cells

Inflammatory mediators present in the tumor milieu may promote cancer progression and are considered promising targets of novel biological therapies. We previously reported that the marine antitumor agent trabectedin, approved in Europe in 2007 for soft tissue sarcomas and in 2009 for ovarian cancer, was able to downmodulate the production of selected cytokines/chemokines in immune cells. Patients

The isothiocyanate produced from glucomoringin inhibits NF-kB and reduces myeloma growth in nude mice in vivo

Glucosinolates (GLs), natural compounds extracted from Brassicaceae and precursors of isothiocyanates (ITCs), have been studied in the last decades mostly due to their chemopreventive activity and, more recently, for their potential use as novel chemotherapeutics. The aim of the present study was to investigate the in vitro and in vivo activity of glucomoringin (GMG), an uncommon member of the GLs

Trabectedin (ET-743) promotes differentiation in myxoid liposarcoma tumors

Differentiation is a complex set of events that can be blocked by rearrangements of regulatory genes producing fusion proteins with altered properties. In the case of myxoid liposarcoma (MLS) tumors, the causative abnormality is a fusion between the CHOP transcription factor and the FUS or EWS genes. CHOP belongs to and is a negative regulator of the large CAAT/enhancer binding protein family whos

The expression of the DeltaNp73beta isoform of p73 leads to tetraploidy

The p73 locus gene has a complex structure encoding a plethora of isoforms. The different DeltaN truncated isoforms of p73 may exert different activities depending on the cellular context. The beta isoform of DeltaNp73 seems to have a particular pattern of action even if its role in cell cycle and mitosis is still under investigation. To gain further knowledge of DeltaNp73beta's function, we inves

Atypical retinoids ST1926 and CD437 are S-phase-specific agents causing DNA double-strand breaks : significance for the cytotoxic and antiproliferative activity

Retinoid-related molecules (RRM) are novel agents with tumor-selective cytotoxic/antiproliferative activity, a different mechanism of action from classic retinoids and no cross-resistance with other chemotherapeutics. ST1926 and CD437 are prototypic RRMs, with the former currently undergoing phase I clinical trials. We show here that ST1926, CD437, and active congeners cause DNA damage. Cellular a

Checkpoint kinase 1 down-regulation by an inducible small interfering RNA expression system sensitized in vivo tumors to treatment with 5-fluorouracil

PURPOSE: After DNA damage, checkpoints pathways are activated in the cells to halt the cell cycle, thus ensuring repair or inducing cell death. To better investigate the role of checkpoint kinase 1 (Chk1) in cellular response to different anticancer agents, Chk1 was knocked down in HCT-116 cell line and in its p53-deficient subline by using small interfering RNAs (siRNA).EXPERIMENTAL DESIGN: Chk1

Role of homologous recombination in trabectedin-induced DNA damage

Trabectedin (ET-743, Yondelis) is a natural marine compound with antitumour activity currently undergoing phase II/III clinical trials. The mechanism of the drug's action is still to be defined, even though it has been clearly demonstrated the key role of Nucleotide Excision Repair (NER). To get further insights into the drug's mode of action, we studied the involvement of the DNA-double strand br

Multi-parametric flow cytometric cell cycle analysis using TO-PRO-3 iodide (TP3) : detailed protocols

TO-PRO-3 iodide (TP3), a monomeric cyanine nucleic acid stain with a peak absorbance at 642 nm and emission at 661 nm, is best excited by a helium-neon (HeNe) laser (633nm). It was tested in monocytes and different cell lines under conditions of different fixatives, dye concentrations, labeling kinetics and RNAse concentrations for mono-, bi- and tri-parametric flow cytometric cell cycle analysis

Dynamics of cell cycle phase perturbations by trabectedin (ET-743) in nucleotide excision repair (NER)-deficient and NER-proficient cells, unravelled by a novel mathematical simulation approach

OBJECTIVES: Trabectedin (ET-743, Yondelis) is a natural marine product, with antitumour activity, currently in phase II/III clinical trials. Previous studies have shown that cells hypersensitive to ultraviolet (UV)-rays because of nucleotide excision repair (NER) deficiency, were resistant to trabectedin. The purpose of this study was to investigate whether this resistance was associated with diff

Modulation of gene transcription by natural products--a viable anticancer strategy

Drug design based on the structure of specific enzymes playing a role in carcinogenesis, e.g. tyrosine kinases, has been successful at identifying novel effective anticancer drugs. In contrast, no success has been achieved in drug design attempts, in which transcription factors or DNA-transcription factor complexes involved in the pathogenesis of human neoplasms were targeted. This failure is like

Antitumor activity of the retinoid-related molecules (E)-3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid (ST1926) and 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) in F9 teratocarcinoma : Role of retinoic acid receptor gamma and retinoid-independent pathways

The retinoid-related molecules (RRMs) ST1926 [(E)-3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid] and CD437 (6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid) are promising anticancer agents. We compared the retinoic acid receptor (RAR) trans-activating properties of the two RRMs and all-trans-retinoic acid (ATRA). ST1926 and CD437 are better RARgamma agonists than ATRA. We

New drugs from the sea

This paper illustrates some biochemical and pharmacological properties of two natural marine products such as trabectedin (ET-743, Yondelis) and aplidine. Trabectedin has shown clinical antitumor activity in refractory soft tissue sarcoma and ovarian cancer. The lack of cross resistance of trabectedin with other chemotherapeutic drugs is presumably related to its peculiar mode of action, that seem