Lanthanide-based peptide biosensor to monitor CDK4/cyclin D kinase activity

We describe a lanthanide biosensor that responds to CDK4 kinase activity in melanoma cell extracts through a significant and dose dependent increase in luminescence, thanks to sensitization of a DOTA[Tb3+] complex incorporated into a CDK4 substrate peptide by a unique tryptophan residue in an adjacent phosphoaminoacid binding moietyThis work was funded by the CNRS (Centre National de la Recherche Scientifique) and a Marie-Curie fellowship EC-FP7 Framework (PIEF-GA-2013-623151) supporting JAGV. CB was funded by the INCA (PRTK-2014). Financial support from the Spanish MINECO (CTQ2015-70698-R), the Xunta de Galicia (Centro singular de investigacio´n de Galicia accreditation 2016–2019), and the European Union (European Regional Development Fund – ERDF), are gratefully acknowledgedS

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

Inhibitors of the Cellular Trafficking of Ricin

Throughout the last decade, efforts to identify and develop effective inhibitors of the ricin toxin have focused on targeting its N-glycosidase activity. Alternatively, molecules disrupting intracellular trafficking have been shown to block ricin toxicity. Several research teams have recently developed high-throughput phenotypic screens for small molecules acting on the intracellular targets required for entry of ricin into cells. These screens have identified inhibitory compounds that can protect cells, and sometimes even animals against ricin. We review these newly discovered cellular inhibitors of ricin intoxication, discuss the advantages and drawbacks of chemical-genetics approaches, and address the issues to be resolved so that the therapeutic development of these small-molecule compounds can progress

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

Coadministration of nanosystems of short silencing RNAs targeting oestrogen receptor α and anti-oestrogen synergistically induces tumour growth inhibition in human breast cancer xenografts

International audienceThe suppression of oestrogen receptor α (ERα) functions by silencing RNAs in association with or not with anti-oestrogens (AEs) both in vitro and in breast cancer cell xenografts was assessed. In vitro, a prolonged decrease in ERα protein expression and an enhanced AE-induced inhibition of ERα-mediated transcription, together with antiproliferative activity, were observed. Incorporation of ERα-siRNAs in pegylated nanocapsules (NC) was achieved; and their intravenous injections in MCF-7 xenografts, in contrast to scramble siRNA containing NCs, lead to decrease in ERα protein content and Ki67 labelling in tumour cells. The pure AE RU58668 (RU) both free and entrapped in stealth nanospheres (NS) at very low concentration (8 μg/kg/week) had no effect on tumour growth evolution. However, coinjection of the two nanocarriers potentiated the decrease in ERα protein, concomitantly with decreasing tumour vasculature and glucose transporter-1. These data support that the targeted delivery of ERα-siRNA in breast tumours potentiates the inhibition of E-induced proliferative activity by encapsulated AE through enhanced anti-vascular activity. In the hormone-independent MDA-MB-231 xenograft model, RU-NS at 4 mg/kg/week induce also a strong tumour vascular normalisation. Together, these findings suggest that the anti-oestrogen activity of RU as well as that of targeted ERα-siRNA leads to anti-angiogenic activity. Their delivery in stealth nanocarriers may constitute a new anti-cancer therapeutic strategy in solid tumours

Estrogen receptor α and β subtype expression and transactivation capacity are differentially affected by receptor-, hsp90- and immunophilin-ligands in human breast cancer cells

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The health status alters the pituitary function and reproduction of mice in a Cxcr2 -dependent manner

International audienceMicrobiota and chronic infections can affect not only immune status, but also the overall physiology of animals. Here, we report that chronic infections dramatically modify the phenotype of Cxcr2 KO mice, impairing in particular, their reproduction ability. We show that exposure of Cxcr2 KO females to multiple types of chronic infections prevents their ability to cycle, reduces the development of the mammary gland and alters the morphology of the uterus due to an impairment of ovary function. Mammary gland and ovary transplantation demonstrated that the hormonal contexture was playing a crucial role in this phenomenon. This was further evidenced by alterations to circulating levels of sex steroid and pituitary hormones. By analyzing at the molecular level the mechanisms of pituitary dysfunction, we showed that in the absence of Cxcr2, bystander infections affect leukocyte migration, adhesion, and function, as well as ion transport, synaptic function behavior, and reproduction pathways. Taken together, these data reveal that a chemokine receptor plays a direct role in pituitary function and reproduction in the context of chronic infections

IL-1β produced by aggressive breast cancer cells is one of the factors that dictate their interactions with mesenchymal stem cells through chemokine production

International audienceThe aim of this work was to understand whether the nature of breast cancer cells could modify the nature of the dialog of mesenchymal stem cells (MSCs) with cancer cells. By treating MSCs with the conditioned medium of metastatic Estrogen-receptor (ER)-negative MDA-MB-231, or non-metastatic ER-positive MCF-7 breast cancer cells, we observed that a number of chemokines were produced at higher levels by MSCs treated with MDA-MB-231 conditioned medium (CM). MDA-MB-231 cells were able to induce NF-κB signaling in MSC cells. This was shown by the use of a NF-kB chemical inhibitor or an IκB dominant negative mutant, nuclear translocation of p65 and induction of NF-κB signature. Our results suggest that MDA-MB-231 cells exert their effects on MSCs through the secretion of IL-1β, that activates MSCs and induces the same chemokines as the MDA-MB-231CM. In addition, inhibition of IL-1β secretion in the MDA-MB-231 cells reduces the induced production of a panel of chemokines by MSCs, as well the motility of MDA-MB-231 cells. Our data suggest that aggressive breast cancer cells secrete IL-1β, which increases the production of chemokines by MSCs

Stapled peptide targeting the CDK4/Cyclin D interface combined with Abemaciclib inhibits KRAS mutant lung cancer growth

Celine Bouclier and Matthieu Simon contributed equally ; Amandine Hurbin and May C. Morris contributed equally.International audienceCDK4/cyclin D kinase constitutes an attractive pharmacological target for development of anticancer therapeutics, in particular in KRAS-mutant lung cancer patients, who have a poor prognosis and no targeted therapy available yet. Although several ATP-competitive inhibitors of CDK4 have been developed for anticancer therapeutics, they suffer from limited specificity and efficacy. Methods: As an alternative to ATP-competitive inhibitors we have designed a stapled peptide to target the main interface between CDK4 and cyclin D, and have characterized its physico-chemical properties and affinity to bind cyclin D1. Results: We have validated a positive correlation between CDK4/cyclin D level and KRAS mutation in lung cancer patients. The stapled peptide enters cells rapidly and efficiently, and inhibits CDK4 kinase activity and proliferation in lung cancer cells. Its intrapulmonary administration in mice enables its retention in orthotopic lung tumours and complete inhibition of their growth when co-administered with Abemaciclib. Conclusion: The stapled peptide targeting the main interface between CDK4 and cyclin D provides promising therapeutic perspectives for patients with lung cancer