New 8-nitroquinolinone derivative displaying submicromolar in vitro activities against both Trypanosoma brucei and cruzi

International audienceAn antikinetoplastid pharmacomodulation study was conducted at position 6 of the 8-nitroquinolin-2(1H)-one pharmacophore. Fifteen new derivatives were synthesized and evaluated in vitro against L. infantum, T. brucei brucei, and T. cruzi, in parallel with a cytotoxicity assay on the human HepG2 cell line. A potent and selective 6-bromo-substituted antitrypanosomal derivative 12 was revealed, presenting EC50 values of 12 and 500 nM on T. b. brucei trypomastigotes and T. cruzi amastigotes respectively, in comparison with four reference drugs (30 nM ≤ EC50 ≤ 13 μM). Moreover, compound 12 was not genotoxic in the comet assay and showed high in vitro microsomal stability (half life >40 min) as well as favorable pharmacokinetic behavior in the mouse after oral administration. Finally, molecule 12 (E° = −0.37 V/NHE) was shown to be bioactivated by type 1 nitroreductases, in both Leishmania and Trypanosoma, and appears to be a good candidate to search for novel antitrypanosomal lead compounds

Régulation et implication de la signalisation de la chimiokine CXCL12 dans la progression du cancer mammaire

RENNES1-BU Santé (352382103) / SudocSudocFranceF

Estrogen represses CXCR7 gene expression by inhibiting the recruitment of NFκB transcription factor at the CXCR7 promoter in breast cancer cells.

International audienceAlthough many studies reported mechanisms involved in the positive regulation of estrogens (E2) target genes, very little is known concerning the repressive effect of E2. In this study, we explored the molecular mechanisms by which E2 regulates CXCR7 expression in breast cancer cells. Our results show that E2-mediated down-regulation of CXCR7 occurs at the transcriptional level as demonstrated using actinomycin D and requires estrogen receptor alpha (ERα). In addition, CXCR7 is a primary ERα-target gene because the effect of E2 does not require the synthesis of an intermediary protein as revealed by the translational inhibitor cycloheximide treatment. Using an inhibitor of the NFκB pathway and chromatin immunoprecipitation assays, we demonstrated that NFκB is necessary for the high expression of CXCR7 gene and is recruited to the proximal promoter of the CXCR7 gene. Interestingly, the chromatin immunoprecipitation analyses also showed that E2-treatment significantly prevented the recruitment of NFκB to the promoter. Altogether, our results demonstrate that E2, through ERα, directly down-regulates CXCR7 expression by interfering with NFκB transcription factor at the promoter level

Involvement of COUP-TFs in Cancer Progression

International audienceThe orphan receptors COUP-TFI and COUP-TFII are members of the nuclear receptor superfamily that play distinct and critical roles in vertebrate organogenesis, as demonstrated by loss-of-function COUP-TFI and/or COUP-TFII mutant mice. Although COUP-TFs are expressed in a wide range of tissues in adults, little is known about their functions at later stages of development or in organism homeostasis. COUP-TFs are expressed in cancer cell lines of various origins and increasing studies suggest they play roles in cell fate determination and, potentially, in cancer progression. Nevertheless, the exact roles of COUP-TFs in these processes remain unclear and even controversial. In this review, we report both in vitro and in vivo data describing known and suspected actions of COUP-TFs that suggest that these factors are involved in modification of the phenotype of cancer cells, notably of epithelial origin

Development and validation of a test for environmental estrogens: Checking xeno-estrogen activity by CXCL12 secretion in BREAST CANCER CELL LINES (CXCL-test).

International audienceSeveral methods have been developed to evaluate and quantify the effects of Endocrine disruptor chemicals (EDC). Nevertheless, most of these methods are time-consuming or not enough sensitive to detect EDC at the environmental range. To link the biological effect of tested EDC to natural protein secretion, we have developed a new screening method based on the secretion of the cytokine CXCL12 (or SDF-1, Stroma-cell Derived Factor 1), which plays a capital role in cell survival and migration. We have demonstrated that CXCL12 secretion is regulated by estrogenic compounds in a dose-dependent way in ER-positive breast cancer cell lines (MCF-7 and T47D). By combining cell culture and ELISA test, we used this up-regulation of CXCL12 secretion to test several major environmental contaminants. Our results showed that 17β-estradiol (from 10(-11) M), 17α-ethynylestradiol (from 10(-12) M), genistein (from 10(-8) M) and bisphenol A (from 10(-6) M) dose-regulate CXCL12 secretion in T47D. In contrast, antiestrogens, raloxifen and 4-hydroxytamoxifen, had no effect on the CXCL12 secretion, but were able to inhibit E2 effect. Moreover, we used cell proliferation assays to evaluate the effect of these different compounds on the growth of T47D cells. We found strong correlation (P = 0.7) between proliferation and CXCL12 secretion. However CXCL12 secretion was as sensitive as cell proliferation assays but appeared more rapid. Thus, this bioassay named CXCL-test (for Checking Xeno-estrogen activity by CXCL12 secretion in breast cancer cell Lines) constitutes a fast and sensitive method for the detection of estrogenic compounds allowing in 14 h to achieve a detection limit of 10(-11) M of E2 (2.7 ng/L)

Development and validation of a testfor environmental estrogens based on the secretion of SDF-1 in breast cancer cells

PosterEndocrine disruptor chemicals (EDC) are exogenous substances that act like hormones and disrupt the physiological functions of endogenous hormones. It constitutes a real focus in environmental concern. Several methods have been developed to evaluate the EDC effects and to quantify them in the environment. Nevertheless, most of them are time consuming and not very sensitive. The detection levels of these methods are frequently not compatible with the environmental range and need a pre-concentration step. In order to link the biological effect of tested compounds to natural protein secretion, we have developed a new EDC screening method based on SDF-1 secretion. SDF-1 (Stroma-cell derived factor 1) is a small cytokine that plays a capital role in cell survival and migration during embryonic development and in adult. We have demonstrated that SDF-1 secretion is regulated by estrogenic compounds in a dose-dependent way in ER-positive breast cancer cell lines (MCF-7 and T47D). By combining cell culture and Elisa test, we used this up-regulation of SDF-1 secretion to screen several major environmental contaminants. Our results show that 17 β estradiol, 17 α ethinylestradiol and genistein dose-regulate SDF-1 secretion. In contrast, antiestrogens, raloxifene and 4 hydroxytamoxifen, have no effect on the SDF-1 secretion. So, this bioassay constitutes a fast and sensitive method for the detection of estrogenic compounds allowing in 24 hours to achieve a detection limit of 10-11 M of E2 (2,7 ng/l) without pre-concentration step

Activation of the MKL1/actin signaling pathway induces hormonal escape in estrogen-responsive breast cancer cell lines.

International audienceEstrogen receptor alpha (ERα) is generally considered to be a good prognostic marker because almost 70% of ERα-positive tumors respond to anti-hormone therapies. Unfortunately, during cancer progression, mammary tumors can escape from estrogen control, resulting in resistance to treatment. In this study, we demonstrate that activation of the actin/megakaryoblastic leukemia 1 (MKL1) signaling pathway promotes the hormonal escape of estrogen-sensitive breast cancer cell lines. The actin/MKL1 signaling pathway is silenced in differentiated ERα-positive breast cancer MCF-7 and T47D cell lines and active in ERα-negative HMT-3522 T4-2 and MDA-MB-231 breast cancer cells, which have undergone epithelial-mesenchymal transition. We showed that MKL1 activation in MCF-7 cells, either by modulating actin dynamics or using MKL1 mutants, down-regulates ERα expression and abolishes E2-dependent cell growth. Interestingly, the constitutively active form of MKL1 represses PR and HER2 expression in these cells and increases the expression of HB-EGF, TGFβ, and amphiregulin growth factors in an E2-independent manner. The resulting expression profile (ER-, PR-, HER2-) typically corresponds to the triple-negative breast cancer expression profile

Estrogen-regulation of CXCL12 axis and involvement in breast cancer cell proliferation

PosterBreast cancer accounts for one-third of cancer diagnoses and is a primary cause of cancer death among women in Western countries. About 70% of breast cancers express estrogen receptor alpha (ERα). Considerable data showed a mitogenic action of estrogen (E2) through ERα in these hormone-dependent cancers. Notably, the regulation of cytokine CXCL12 seems to be a key mediator of the growth effect of E2 in breast cancer. This cytokine is also known to play an important role in cell survival and migration during embryonic development and in adult. Two G protein-coupled receptors, CXCR4 and CXCR7, are known to bind CXCL12. The first one, CXCR4, has been widely studied in cell migration and in metastatic potential of tumor cells that over-express this chemokine receptor. In contrast, involvement of the second receptor, CXCR7, which was discovered more recently as a target of CXCL12, remains unclear in carcinogenesis. The aim of our study was to examine the regulation of the CXCL12 axis components by E2 and selective ER modulators including agonists and antagonists. For this purpose, we have analysed E2-regulation of CXCL12, CXCR4 and CXCR7 mRNA and protein levels by quantitative real-time PCR, Western-blot, ELISA or FACS analysis in ER-positive MCF-7 breast cancer cells. Interestingly, our data showed, for the first time, that CXCR4 and CXCR7 chemokine receptors are differentially regulated by E2, in a dose- and time-dependent manner. While the expression of CXCL12 and CXCR4 transcripts and proteins are positively regulated by E2 and xeno-estrogens, the expression of CXCR7 is negatively regulated. Surprisingly, at low concentrations, anti-estrogens increased the expression of CXCR4 transcript but not those of CXCL12 and CXCR7. Furthermore, the importance of CXCL12 axis was evaluated on basal and E2-dependent MCF-7 cell proliferation by using specific siRNA directed against CXCL12, CXCR4 and CXCR7. This analysis demonstrated that the E2-regulation of CXCL12 axis contributes to the effect of E2 in breast cancer cell proliferation

Engineering Functionality Gradients by Dip Coating Process in Acceleration Mode

International audienceIn this work, unique functional devices exhibiting controlled gradients of properties are fabricated by dip-coating process in acceleration mode. Through this new approach, thin films with ``on-demand'' thickness graded profiles at the submillimeter scale are prepared in an easy and versatile way, compatible for large-scale production. The technique is adapted to several relevant materials, including sol-gel dense and mesoporous metal oxides, block copolymers, metal-organic framework colloids, and commercial photoresists. In the first part of the Article, an investigation on the effect of the dip coating speed variation on the thickness profiles is reported together with the critical roles played by the evaporation rate and by the viscosity on the fluid draining-induced film formation. In the second part, dip-coating in acceleration mode is used to induce controlled variation of functionalities by playing on structural, chemical, or dimensional variations in nano- and microsystems. In order to demonstrate the full potentiality and versatility of the technique, original graded functional devices are made including optical interferometry mirrors with bidirectional gradients, one-dimensional photonic crystals with a stop-band gradient, graded microfluidic channels, and wetting gradient to induce droplet motion