Estrogenic or antiestrogenic therapies for multiple myeloma?

Multiple myeloma (MM) is a common hematological malignancy which remains incurable due to both intrinsic and acquired resistance to conventional or more novel drugs. Estrogenic and antiestrogenic compounds are very promising drugs for the treatment of MM. Indeed, they inhibit cell proliferation in vitro. They block cell cycle and/or induce apoptosis even in drug-resistant MM cells but not normal B cells. They interfere with survival pathways often deregulated in myelomas. They co-operate with conventional drugs to enhance apoptosis or to overcome resistance. In vivo, they act also on tumoral angiogenesis in xenograft models. As a whole, they possess all the criteria which render them attractive for a new therapeutic strategy. Importantly, they are well-tolerated at the doses tested in vitro or in vivo, encouraging the rapid onset of critical trials

Nanoparticles loaded with ferrocenyl tamoxifen derivatives for breast cancer treatment.

International audienceFor the first time, two organometallic triphenylethylene compounds (Fc-diOH and DFO), with strong antiproliferative activity in breast cancer cells, but insoluble in biological fluids, were incorporated in two types of stealth nanoparticles (NP): PEG/PLA nanospheres (NS) and nanocapsules (NC). Their physicochemical parameters were measured (size, zeta potential, encapsulation and loading efficiency), and their biological activity was assessed. In vitro drug release after high dilution of loaded NPs was measured by estradiol binding competition in MELN cells. The influence of the encapsulated drugs on the cell cycle and apoptosis was studied by flow cytometry analyses. Notwithstanding potential drug adsorption at the NP surface, Fc-diOH and DFO were incorporated efficiently in NC and NS, which slowly released both compounds. They arrested the cell cycle in the S-phase and induced apoptosis, whose activity is increased by loaded NS. A decrease in their antiproliferative activity by the antioxidant alpha-tocopherol indicated that reactive oxygen species (ROS) may be involved. Therefore, nanosystems, containing for the first time a high load of anticancer organometallic triphenylethylenes, have been developed. Their small size and delayed drug release, combined with their enhanced apoptotic potential, are compatible with an increased persistence in the blood and a promising antitumour activity

Anti-oestrogènes dans le myélome multiple (évaluation biologique des potentialités thérapeutiques de liposomes chargés en RU 58668)

Le myélome multiple (MM) est une pathologie multiple des plasmocytes qui aujourd'hui reste encore incurable. Aux États-Unis, cette pathologie présente une prévalence de 50 000 patients en 2005 ainsi qu'une incidence de 15270 nouveaux cas par an. Les stratégies thérapeutiques employées dans le MM font appel, comme dans beaucoup de cancers localisés, à la radiothérapie et à la chimiothérapie, seules ou en association. Depuis quelques années, les protocoles de traitements appliqués au MM ont certes évolués mais rares sont les nouvelles drogues qui ont rejoint l'arsenal thérapeutique. Parmi les nouvelles molécules décrites ces dernières années, on peut noter les anti-œstrogènes (AEs) comme le RU 58668 (RU), dont le rôle est de bloquer l'effet mitogénique des œstrogènes. Si toutes les voies d'action des AEs ont bien été décrites dans des modèles mammaires, on ne connaît pas encore les voies impliquées dans le MM. Après avoir vérifié la présence de recepteurs aux œstrogènes dans des lignées cellulaires de MM, nous avons étudié les potentialités cytotoxiques du RU sur ces mêmes lignées. Afin d'étudier les potentialités thérapeutiques in vivo des AEs pour le MM, et notamment celles du RU, nous l'avons incorporé dans un système de délivrance colloïdal récemment utilisé en clinique dans le traitement du MM : des liposomes pégylés. Ces liposomes composés de phosphatidycholine d'œuf (EPC), de cholestérol (CHOL) et de phosphatidyléthanolamine pégylée (DSPE-PEG2000) ont permis d'incorporer une charge de 1 mM de RU . Leur taille de 100nm est compatible avec une extravasation. In vitro, des analyses en cytométrie de flux montrent que le RU libre induit soit un arrêt en phase G0/G1 soit une apoptose.Multiple myelome (MM) is a pathology of plasma cells wich today still remains incurable. In the united States, this pathology presents a prevalence of 50 000 patients in 2005 as well as an incidence of 15270 new cases per year. As in many located cancers, the therapeutic strategies employedin the MM consists in radiotherapy and chemotherapy, alone or in association. Since few years, the protocols of treatments applied to the MM have certainly evolved but rarer are new drugs wich joined the therapeutic arsenal. Among the new described molecules these last years we can notice the anti-estrogens (AEs) like the RU 58668 (RU), whose role is back to block the mitogenc effects of estrogens. If all the ways of action of AEs were indeed described in mammary models, we do not know yet the way implied in the MM. After having checked the presence of estrogen receptors in cellular lines of MM, we studied the cytotoxic potentialities of RU on these same lines. In order to study in vivo therapeutic potentialities of AEs for the MM, and in particular those of RU, we incorporated it in a colloïdal delivery system recently used in clinic for the treatment of MM : pegylated liposomes. These liposomes composed od egg phosphatidylcholine (EPC), cholesterol (CHOL) and pegylated phophatidylethanolamine (DSPE-PEG2000) render possible to incorporate a load of 1mM RU. Their 100 nm size is compatible with their extravation. In vitro, flow cytometry analyses show that free in RU induced either a G0/G1 phase arrest or apoptosis of MMcells. Ru incorporation in liposomes of EPC/CHOL/DSPE/ PEG 2000 (64 : 30 6) induce the apoptosis of MM cells for a concentration of 1 M RU.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Fonction de la forme beta du récepteur des oestrogènes dans les cellules de cancer du sein (ouverture vers de nouvelles stratégies thérapeutiques)

Le ligand, le promoteur et la lignée cellulaire influencent les capacités transactivatrices des récepteurs aux œstrogènes (ER) a et b. Le contexte cellulaire (expression/acétylation de ER/des corégulateurs) module l activité suppressive de ERb, dépendante de son AF1, envers ERa. Trois approches anticancéreuses ont été testées : l anti-œstrogène pur RU 58668 induit la dégradation protéasomale de ERa, réduit sa capacité de transactivation mais affecte peu ERb, facteur de bon pronostic. Les inhibiteurs d histone-déacétylases, agents pro-apoptotiques et cytostatiques, provoquent la dégradation de ERa mais stabilisent ERb. L association de ces deux agents anticancéreux augmente les effets antiprolifératifs et pro apoptotiques observés sur des cellules MCF-7 ERa+ERb+ avec ces molécules seules. Enfin, les inhibiteurs de la hsp90, chaperon de ER, provoquent sa dégradation protéasomale, inhibent son activité transcriptionnelle, induisent l apoptose des cellules et bloquent leur prolifération.The transactivation capacity of estrogen receptor (ER) a and b was influenced by the ligand, the promoter and the cell line. The cellular background (expression/acetylation of ER/coregulators) modulated the AF-1-dependent suppressive activity of ERb against ERa. Three therapeutic strategies were tested: the pure antiestrogen RU 58668 induced a proteasome-mediated ERa degradation, decreased its transactivation capacity without affecting ERb associated to a good prognostic. Histone deacetylase inhibitors exerted pro-apoptotic and anti-proliferative activities, induced a proteasome-mediated ERa-degradation but stabilized ERb. The association of these two drugs increased the anti-proliferative and pro-apoptotic effects of this agents alone on MCF-7 cells transiently expressing ERb. Finally, inhibitors of the ER chaperone hsp90 induced apoptosis and growth arrest of breast cancer cells associated with proteasomal degradation of both ERs and inhibition of their transcriptional activities.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Potentiel thérapeutique d'une formulation nanoparticulaire d'ARN interférents ciblant la forme alpha du récepteur des oestrogènes dans le cancer du sein

Le cancer du sein est le cancer le plus fréquent chez la femme dans les pays occidentaux. De nombreuses études ont montré l implication de la forme alpha du récepteur des œstrogènes (ERa) dans la tumorigenicité des œstrogènes. Mon travail a été de développer une stratégie thérapeutique innovante basée sur une formulation nanoparticulaire incorporant des siRNA ciblant ERa. In vitro, dans des cellules de cancer du sein MCF-7 œstrogéno-sensibles, les siRNA induisent une réduction de l expression de ERa ainsi que de son activité. In vivo, après incorporation dans des nanocapsules de PEG-PCL/MA, les siRNA ciblant ERa induisent à un ralentissement de la croissance tumorale, une réduction de l expression de ERa et de la vascularisation tumorale. La co-administration avec un anti-œstrogène pur potentialise ces effets. Cette activité pourrait s avérer être une stratégie prometteuse pour potentialiser l activité anti-tumorale d autres agents anti-cancéreux.Breast cancer is the most frequent woman cancer in western countries. Many studies have shown the involvement of the estrogen receptor alpha isotype (ERa) in the estrogen tumorigenicity. My work consisted to develop a therapeutic strategy based on nanoparticular formulation incorporating ERa-targeted siRNA. In vitro, in MCF-7 estrogen-dependent breast cancer cells, siRNA targeting ERa induced a reduced ERa expression and decreased its activity. In vivo, after incorporation in nanocapsules of PEG-PCL/MA, siRNA-ERa leads to slow down tumor growth and to a reduction of ERa expression and tumor vasculature. Co-administration with a pure anti-estrogen potentiated these affects. This could be a promising strategy to potentiate activity of other anti-cancer agents.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Préparation ét évaluation biologique de nanosphères et de nanaocapsules à base de copolymères polyester/polyéthylène-glycol chargées en antioestrogène

L 'hormonothérapie des cancers oestrogéno-dépendants chez les femmes ménopausées restait majoritairement basée sur l'utilisation du Tamoxifène. Récemment, un anti-oestrogène (RU 58668) " pur" a été identifié comme capable de lever la résistance au Tamoxifène. Afin de limiter ses effets secondaires et obtenir une accumulation tumorale, nous avons formulé plusieurs préparations galéniques à base de copolymères biodégradables. Après encapsulation du RU 58668 et du Tamoxifène au sein de nanosphères ou nanocapsules a contenu huileux, les tailles obtenues mesurées par microscopie électroniques après cryofracture, restent toujours compatibles avec une extravasation qui se vérifie in vivo. Le couplage de chaînes de PEG à la surface des formulations diminue l'adsorption des opsonines, un prérequis nécessaire à la prolongation du temps de circulation plasmatique. ln vitro, des expériences utilisant des lignées cellulaires de cancer du sein humain ont montré que l' encapsulation des anti-oestrogènes retardait et prolongeait leurs activités anti-prolifératives. ln vivo, la pegylation des formulations prolonge l'activité anti-utérotrophique des anti-oestrogènes et induit une régression tumorale sur des xénogreffes à cellules de cancers du sein humain oestrogéno-sensibles (MCF-7) ou insensibles (MCF-7/Ras).Ces résultats suggèrent que l'encapsulation d'un anti-oestrogène au sein de nanoparticules constitue un système de " drug delivery " prometteurStealth nanoparticles made of polyester-PEG copolymer, nanospheres or nanocapsules with an oily core were loaded with the mixed antiestrogen 40H- Tamoxifen or the "pure" antiestrogen RU 58668. The nanoparticle size (120 to 250 nm) is compatible with a capacity to cross through the discontinous tumoral endothelium. Pegylation of aIl nanoparticles allows them to resist to the opsonization process and macrophage capture, leading to an increase of blood circulation time. Nanoparticles are characterized in vitro by a prolonged and delayed inhibition of estrogen-induced reporter gene expression in MELN cells. ln vivo, a prolonged antiuterotrophic activity of encapsulated antiestrogen occurs. ln human breast cancer MCF- 7 cells xenografts as weIl as the estradiol insensitive MCF -7/Ras cells tumors, antiestrogen loaded nanoparticles inhibit tumor growth progression. Altogether these data suggest that incorpration of an antiestrogen into long circulating systems enhance its antitumoral activity and may constitute a promising delivery system for breast cancer treatmentCHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Intérêt de la vectorisation des inhibiteurs de kinases dépendantes des cyclines (CDKs) et potentialité dans le traitement du cancer

Les Cdks sont des protéines essentielles dans le déclenchement et le déroulement des étapes du cycle cellulaire. Très fréquemment dérégulées dans les tumeurs humaines, elles sont apparues commes des cibles privilégiées de molécules potentiellemnt anticancéreuses. Plusieurs inhibiteurs puissants et sélectifs de Cdks ont été identifiés. ils inactivent les complexe Cycline/Cdk en interférant avec la liaison de l'ATP à la kinase. Cependant, leur administration nécessite une forte concentration au niveau tumoral. De plus, les effets sur les cellules saines sont responsables de toxicité. La mise au point de vecteurs colloïdaux furtifs représente une stratégie intéressante pour l'administration intraveineuse de ces moléculkes dans le traitement des tumeurs solides.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Estrogen receptor signaling as a target for novel breast cancer therapeutics.: new targets in estradiol receptor-positive breast cancers

International audienceIn breast cancer (BC) epithelial cells, the mitogenic action of estradiol is transduced through binding to two receptors, ERα and ERβ, which act as transcription factors. Anti-estrogens (AEs) and aromatase inhibitors (AIs) are used clinically to arrest the estrogen-dependent growth of BC. In the case of AE or AI resistance, Herceptin or lapatinib may be used to inhibit growth factors. Estrogen effects are mediated not only through nuclear ERs but also through cytoplasmic/membrane ERs and G-protein-coupled ERs. These estrogen-binding systems associate with various proteins that direct cell cycle signaling, proliferation and survival. The partners of nuclear ER include SRC1-3, HDACs and ERβ itself as well as newly identified proteins, such as E6-AP, LKB1, PELP1, PAX-2 and FOXA1. The partners of extra-nuclear ERα include PI3K and the tyrosine kinase Src. These various factors are all potential targets for therapeutic intervention. In addition, BC proliferation is enhanced by insulin and EGF, which stimulate signaling through the MAPK and PI3K/AKT pathways by activation of the IGF-1R and EGFR axes, respectively. These pathways are tightly interconnected with ER-activated signaling, and membrane ERα forms complexes with Src and PI3K. Chemokine-mediated signaling also modulates the estrogen response. Inhibiting these pathways with specific inhibitors or activating some of the pathways by gene manipulation may be therapeutically valuable for arresting BC cell cycle progression and for inducing apoptosis to antagonize hormone-resistance. Here, we review some newly identified putatively targetable ER partners and highlight the need to develop tumor-targeting drug carrier systems affecting both the tumor cells and the tumor environment

Anticancer Drugs in Liposomal Nanodevices: A Target Delivery for a Targeted Therapy

International audienceFor many years, nanocarriers have been investigated to modify pharmacokinetics and biodistribution of various active molecules. In the cancer domain, one of the biggest challenges still remains the improvement of the therapeutic index, often too low, for the majority of antitumor drugs. The application of nanotechnologies for the treatment and the diagnosis of cancers are nowadays currently developed, or under development, and liposomes play an important role in the history of nanodevices. Because of their high degree of biocompatibility, lipid nanosystems have been used to improve pharmacological profiles of various anticancer drugs otherwise discarded because of their low water solubility, poor bioavailability or either fragile and subjected to rapid biotransformations. This review aims at introducing an overview of the last 40 years of liposome researches until the last liposomal formulations commercially available or undergoing clinical trials. Liposome properties will be described, with a particular emphasis over the last generation of carriers appreciated for their active targeting characteristics. Researchers foresee a remarkable impact of nanotechnologies in the field of medicine; this review will try to summarize the main concepts over liposome domain, which can count on encouraging results as target therapy associated with targeted delivery