scholarly journals FLTX2: A Novel Tamoxifen Derivative Endowed with Antiestrogenic, Fluorescent, and Photosensitizer Properties

2021 ◽  
Vol 22 (10) ◽  
pp. 5339
Author(s):  
Mario Díaz ◽  
Fernando Lobo ◽  
Dácil Hernández ◽  
Ángel Amesty ◽  
Catalina Valdés-Baizabal ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Design ◽  
Apoptotic Cell ◽  
Irradiation Time ◽  
Covalent Binding ◽  
Breast Tumour ◽  
Time Dependent ◽  
Tamoxifen Treatment ◽  
Binding Core ◽  
Er Positive

Tamoxifen is the most widely used selective modulator of estrogen receptors (SERM) and the first strategy as coadjuvant therapy for the treatment of estrogen-receptor (ER) positive breast cancer worldwide. In spite of such success, tamoxifen is not devoid of undesirable effects, the most life-threatening reported so far affecting uterine tissues. Indeed, tamoxifen treatment is discouraged in women under risk of uterine cancers. Recent molecular design efforts have endeavoured the development of tamoxifen derivatives with antiestrogen properties but lacking agonistic uterine tropism. One of this is FLTX2, formed by the covalent binding of tamoxifen as ER binding core, 7-nitrobenzofurazan (NBD) as the florescent dye, and Rose Bengal (RB) as source for reactive oxygen species. Our analyses demonstrate (1) FLTX2 is endowed with similar antiestrogen potency as tamoxifen and its predecessor FLTX1, (2) shows a strong absorption in the blue spectral range, associated to the NBD moiety, which efficiently transfers the excitation energy to RB through intramolecular FRET mechanism, (3) generates superoxide anions in a concentration- and irradiation time-dependent process, and (4) Induces concentration- and time-dependent MCF7 apoptotic cell death. These properties make FLTX2 a very promising candidate to lead a novel generation of SERMs with the endogenous capacity to promote breast tumour cell death in situ by photosensitization.

Serum deprivation induces apoptotic cell death in a subset of Balb/c 3T3 fibroblasts

1994 ◽  
Vol 107 (5) ◽  
pp. 1169-1179 ◽  
Author(s):  
G.V. Kulkarni ◽  
C.A. McCulloch
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Time Dependent ◽  
Cell Diameter ◽  
Adherent Cells ◽  
Serum Withdrawal ◽  
3T3 Fibroblasts ◽  
Mean Diameter

Little is known about the regulation of apoptosis in fibroblasts although several model systems including serum deprivation and treatment with staurosporine or topoisomerase inhibitors have been used to induce apoptosis in vitro. To validate a reproducible in vitro model for the study of apoptosis in fibroblasts, we cultured density-inhibited monolayer cultures of Balb/c 3T3 fibroblasts in Dulbecco's modified essential medium plus 15% fetal calf serum and then withdrew serum. Time-lapse video microscopy demonstrated that within minutes of serum withdrawal, cells lost substrate attachment and floated to the top of the liquid growth medium. There was a time-dependent increase in the number of non-adherent cells. Some of these cells regained attachment and spread momentarily, but they eventually rounded up and lost attachment permanently. In contrast to serum-containing cultures in which similar morphological changes were followed by mitosis, in serum-free cultures repeated attempts at mitosis were followed by permanent attachment loss and presumably cell death. To assess whether all the non-adherent cells were in fact dead, the percentages of cells that continued to proliferate upon return to serum-supplemented conditions was computed. After various periods of serum starvation a decreasing proportion (approx. 75% at 30 minutes; < 2% at 24 hours) of the non-adherent cells could be rescued by addition of serum. Transmission electron microscopy of cells 3 hours after serum withdrawal showed that the majority (approximately 60%) of non-adherent cells exhibited marked intranuclear chromatin condensation but maintained integrity of cell and nuclear membranes and cell organelles, morphological changes consistent with those of apoptotic cell death. Scanning electron microscopy of cultures 3 hours following serum withdrawal showed rounded cells with marked surface blebbing. Fluorescence and confocal microscopy revealed increased intensity of nuclear staining with DAPI while actin filaments became indistinct or collapsed around the nucleus. After cycloheximide treatment to inhibit protein synthesis, there was no reduction of apoptosis. Gel electrophoresis of DNA from both control and 3 hour-serum-deprived cells showed intact DNA with no oligonucleosomal length fragmentation. After serum withdrawal, intracellular calcium was reduced by about 32% over 5 minutes as measured by fura2 ratio fluorimetry in single cells. Serum-starved cells showed a time-dependent shrinkage in mean cell diameter compared to trypsinized, adherent control cells (at 0 hours, mean diameter = 18.0 microns--viable; at 4 hours, mean diameter = 15.5 microns--apoptotic). Flow cytometric analysis showed increased propidium iodide staining and reduced fluorescein diacetate uptake over 3 hours, changes that were contemporaneous with the reduction of cell diameter.(ABSTRACT TRUNCATED AT 400 WORDS)

Progressive apoptotic cell death triggered by transient oxidative insult in H9c2 rat ventricular cells: a novel pattern of apoptosis and the mechanisms

2004 ◽  
Vol 286 (6) ◽  
pp. H2169-H2182 ◽  
Author(s):  
Hong Han ◽  
Hong Long ◽  
Huizhen Wang ◽  
Jingxiong Wang ◽  
Yiqiang Zhang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Time Dependent ◽  
Ros Production ◽  
Cytochrome C Release ◽  
Ventricular Cells ◽  
Mitochondrial Death Pathway ◽  
Oxidative Insult

Many pathophysiological processes are associated with oxidative stress and progressive cell death. Oxidative stress is an apoptotic inducer that is known to cause rapid cell death. Here we show that a brief oxidative insult (5-min exposure to 400 μM H2O2), although it did not kill H9c2 rat ventricular cells during the exposure, triggered an intracellular death cascade leading to delayed time-dependent cell death starting from 1 h after the insult had been withdrawn, and this post-H2O2 cell death cumulated gradually, reaching a maximum level 8 h after H2O2 withdrawal. By comparison, sustained exposure to H2O2 caused complete cell death within a narrow time frame (2 h). The time-dependent post-H2O2 cell death was typical of apoptosis, both morphologically (cell shrinkage and nuclear condensation) and biochemically (DNA fragmentation, extracellular exposure of phosphatidylserines, and caspase-3 activation). A dichlorofluorescein fluorescent signal showed a time-dependent endogenous increase of reactive oxygen species (ROS) production, which was almost abolished by inhibition of the mitochondrial electron transport chain. Application of antioxidants (vitamin E or DTT) before H2O2 addition or after H2O2 withdrawal prevented the H2O2-triggered progressive ROS production and apoptosis. Sequential appearance of events associated with activation of the mitochondrial death pathway was found, including progressive dissipation of mitochondrial membrane potential, cytochrome c release, and late activation of caspase-3. In conclusion, transient oxidative stress triggers an intrinsic program leading to self-sustained apoptosis in H9c2 cells via cumulative production of mitochondrial ROS and subsequent activation of the mitochondrial death pathway. This pattern of apoptosis may contribute to the progressive and long-lasting cell loss in some degenerative diseases.

Dose- and time-dependent effects of TNFα and actinomycin D on cell death incidence and embryo growth in mouse blastocysts

Zygote ◽  
2007 ◽  
Vol 15 (3) ◽  
pp. 241-249 ◽  
Author(s):  
D. Fabian ◽  
S. Juhás ◽  
G. Il'ková ◽  
J. Koppel
Keyword(s):  
Cell Death ◽  
Caspase 3 ◽  
Actinomycin D ◽  
Culture Media ◽  
Apoptotic Cell ◽  
Cell Damage ◽  
Time Dependent ◽  
Preimplantation Embryos ◽  
Induced Apoptosis

SummaryThis study was undertaken to obtain information about characteristics of different types of induced apoptosis in preimplantation embryos. Freshly isolated mouse blastocysts were cultured in vitro with the addition of two apoptotic inductors – TNFα and actinomycin D – at various doses and times. The average number of nuclei and the percentage of dead cells were evaluated in treated embryos. Classification of dead cells was based on morphological assessment of their nuclei evaluated by fluorescence microscopy, the detection of specific DNA degradation (TUNEL assay), the detection of active caspase-3 and cell viability assessed by propidium iodide staining. The addition of both apoptotic inductors into culture media significantly increased cell death incidence in blastocysts. Their effects were dose and time dependent. Lower concentrations of inductors increased cell death incidence, usually without affecting embryo growth after 24 h culture. Higher concentrations of inductors caused wider cell damage and also retarded embryo development. In all experiments, the negative effect of actinomycin D on blastomere survival and blastocyst growth was greater than the effect of TNFα. Furthermore, the addition of actinomycin D into culture media increased cell death incidence even after 6 h culture. Differences resulted probably from diverse specificity of apoptotic inductors. The majority of dead cells in treated blastocysts were of apoptotic origin. Morphological and biochemical features of apoptotic cell death induced by both TNFα and actinomycin D were similar and had homologous profile. In blastomeres, similarly to somatic cells, the biochemical pathways of induced apoptosis included activation of caspase-3 and internucleosomal DNA fragmentation.

scholarly journals Photo-Functionalized Magnetic Nanoparticles as a Nanocarrier of Photodynamic Anticancer Agent for Biomedical Theragnostics

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 571 ◽  
Author(s):  
Ki Chang Nam ◽  
Yong Soo Han ◽  
Jong-Min Lee ◽  
Si Chan Kim ◽  
Guangsup Cho ◽  
...  
Keyword(s):  
Cell Death ◽  
Cancer Cell ◽  
Quantitative Methods ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Irradiation Time ◽  
Dependent Manner ◽  
Anticancer Activities ◽  
Qualitative And Quantitative Methods

Various theragnostic agents have been devised and developed as cancer treatments; however, existing agents are often limited by their specific functions and complexities. Here, we report multifunctional magnetite (Fe3O4) nanoparticles functionalized with chlorin e6 (Ce6) and folic acid (FA) using a simple fabrication process to be used as theragnostic agents in photodynamic therapy (PDT). The effectiveness of cellular uptake of Fe3O4-Ce6-FA nanoparticles (FCF NPs) and its visualization as well as the photodynamic anticancer activities were evaluated. The mechanism of cancer cell death by the FCF NPs was also verified with qualitative and quantitative methods. Results indicate that FCF NPs have good penetration efficacy, resulting in excellent in vitro fluorescence and magnetic resonance imaging in cancer cells. FCF NPs exhibited promising anticancer activity in an irradiation time- and FCF NPs-dose-dependent manner in various cancer cell lines, leading to apoptotic cell death via morphological changes in cell membrane, nuclear, and DNA damage, and via overexpression of apoptosis-related genes, such as ZFP36L1, CYR61, GADD45G, caspases-2, -3, -9, 10, and -14. This study suggests that FCF NPs may be safely used in cancer therapy via PDT and could be a versatile therapeutic tool and biocompatible theragnostic agent, which may be used in diagnostic imaging.

scholarly journals The proapoptotic gene interferon regulatory factor-1 mediates the antiproliferative outcome of paired box 2 gene and tamoxifen

Oncogene ◽  
2020 ◽  
Vol 39 (40) ◽  
pp. 6300-6312
Author(s):  
Shixiong Wang ◽  
Venkata S. Somisetty ◽  
Baoyan Bai ◽  
Igor Chernukhin ◽  
Henri Niskanen ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Growth ◽  
Interferon Regulatory Factor ◽  
Estrogen Signaling ◽  
Tamoxifen Treatment ◽  
Dependent Manner ◽  
Breast Cancer Patients ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 1 ◽  
Er Positive

Abstract Tamoxifen is the most prescribed selective estrogen receptor (ER) modulator in patients with ER-positive breast cancers. Tamoxifen requires the transcription factor paired box 2 protein (PAX2) to repress the transcription of ERBB2/HER2. Now, we identified that PAX2 inhibits cell growth of ER+/HER2− tumor cells in a dose-dependent manner. Moreover, we have identified that cell growth inhibition can be achieved by expressing moderate levels of PAX2 in combination with tamoxifen treatment. Global run-on sequencing of cells overexpressing PAX2, when coupled with PAX2 ChIP-seq, identified common targets regulated by both PAX2 and tamoxifen. The data revealed that PAX2 can inhibit estrogen-induced gene transcription and this effect is enhanced by tamoxifen, suggesting that they converge on repression of the same targets. Moreover, PAX2 and tamoxifen have an additive effect and both induce coding genes and enhancer RNAs (eRNAs). PAX2–tamoxifen upregulated genes are also enriched with PAX2 eRNAs. The enrichment of eRNAs is associated with the highest expression of genes that positivity regulate apoptotic processes. In luminal tumors, the expression of a subset of these proapoptotic genes predicts good outcome and their expression are significantly reduced in tumors of patients with relapse to tamoxifen treatment. Mechanistically, PAX2 and tamoxifen coexert an antitumoral effect by maintaining high levels of transcription of tumor suppressors that promote cell death. The apoptotic effect is mediated in large part by the gene interferon regulatory factor 1. Altogether, we conclude that PAX2 contributes to better clinical outcome in tamoxifen treated ER-positive breast cancer patients by repressing estrogen signaling and inducing cell death related pathways.

scholarly journals A small-molecule inhibitor of the BRCA2-RAD51 interaction modulates RAD51 assembly and potentiates DNA damage-induced cell death

2020 ◽  
Author(s):  
Duncan E. Scott ◽  
Nicola J. Francis-Newton ◽  
May E. Marsh ◽  
Anthony G. Coyne ◽  
Gerhard Fischer ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Molecular Design ◽  
Apoptotic Cell ◽  
Dna Recombination ◽  
Binding Pocket ◽  
Protein Protein Interaction ◽  
Cycle Arrest ◽  
Molecule Inhibitor ◽  
Molecular Clustering

SUMMARYBRCA2 controls RAD51 recombinase during homologous DNA recombination (HDR) through eight evolutionarily-conserved BRC repeats, which individually engage RAD51 via the motif Phe-x-x-Ala. Using structure-guided molecular design, templated on a monomeric thermostable chimera between human RAD51 and archaeal RadA, we identify CAM833, a 529 Da orthosteric inhibitor of RAD51:BRC with a Kd of 366 nM. The quinoline of CAM833 occupies a hotspot, the Phe-binding pocket on RAD51 and the methyl of the substituted α-methylbenzyl group occupies the Ala-binding pocket. In cells, CAM833 diminishes formation of damage-induced RAD51 nuclear foci; inhibits RAD51 molecular clustering, suppressing extended RAD51 filament assembly; potentiates cytotoxicity by ionising radiation, augmenting 4N cell-cycle arrest and apoptotic cell death and works with poly-ADP ribose polymerase (PARP)1 inhibitors to suppress growth in BRCA2-wildtype cells. Thus, chemical inhibition of the protein-protein interaction between BRCA2 and RAD51 disrupts HDR and potentiates DNA damage-induced cell death, with implications for cancer therapy.

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