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The identification of novel therapeutic strategies is an important urgent requirement for the clinical management of ovarian cancer, which remains the leading cause of death from gynecologic cancer. Several studies have shown that the antiapoptotic proteins Bcl-xL and Mcl-1, as well as the proapoptotic protein Bim, are key elements to be modulated to kill ovarian cancer cells. Pharmacologic inhibition of Bcl-xL is possible by using BH3-mimetic molecules like ABT-737. However, inhibition of Mcl-1 and/or promotion of its BH3-only partners (including Bim, Puma, and Noxa) remains a challenge that may be achieved by modulating the signaling pathways upstream. This study sought whether AZD8055-induced mTOR inhibition and/or trametinib-induced MEK inhibition could modulate Mcl-1 and its partners to decrease the Mcl-1/BH3-only ratio and thus sensitize various ovarian cancer cell lines to ABT-737. AZD8055 treatment inhibited Mcl-1 and increased Puma expression but did not induce massive apoptosis in combination with ABT-737. In contrast, trametinib, which decreased the Mcl-1/BH3-only protein ratio by upregulating Puma and dephosphorylated active Bim, sensitized IGROV1-R10 and OVCAR3 cells to ABT-737. Adding AZD8055 to trametinib further reduced the Mcl-1/BH3-only protein ratio and triggered apoptosis without ABT-737 in IGROV1-R10 cells. Moreover, the AZD8055/trametinib association highly sensitized all cell lines including SKOV3 to ABT-737, the induced dephosphorylated Bim being crucial in this sensitization. Finally, the three-drug combination was also very efficient when replacing AZD8055 by the pan-Akt inhibitor MK-2206. This study thus proposes original multitargeted strategies and may have important implications for the design of novel approaches for ovarian cancer treatment. Mol Cancer Ther; 16(1); 102–15. ©2016 AACR.

The identification of novel therapeutic strategies is an important urgent requirement for the clinical management of ovarian cancers, which remain the leading cause of death from gynecologic cancer. Our previous studies have shown that the anti-apoptotic proteins Bcl-xL and Mcl-1 cooperate to protect resistant ovarian cancer cells from apoptosis as their concomitant inhibition results in massive apoptotic cell death. Moreover, their BH3-only pro-apoptotic partners Bim and Puma are crucial actors in the induced cell death. This suggests that ovarian cancer cell apoptosis can be triggered by inhibiting Bcl-xL and Mcl-1 and/or by promoting their BH3-only partners, especially Bim and Puma. The expression of these Bcl-2 family proteins has been reported to be modulated by HDAC (histone deacetylases) inhibitors in various cancer models. The objective of the present study was to evaluate the efficacy of the FDA-approved pan-HDAC inhibitor belinostat (i) to reduce the [Bcl-xL and Mcl-1] / BH3-only proteins ratio and (ii) to trigger apoptosis in chemoresistant ovarian cancer cell lines, alone or in combination with other pharmacological molecules that modulate these Bcl-2 family proteins. HDAC inhibition by belinostat led to a G2/M blockade and consequently reduced cell proliferation. Moreover, belinostat used at high concentrations (from 1000 to 2000 nM) efficiently triggered apoptosis in chemoresistant ovarian cancer cells. This cytotoxic effect was associated with both an up-regulation of Bim and Puma protein expression and an inhibition of Bcl-xL protein expression. Used at sub-toxic concentrations, belinostat also up-regulated Bim and Puma proteins but failed to down-regulate Bcl-xL and Mcl-1 protein expression. We therefore investigated whether Bcl-xL or Mcl-1 inhibition could sensitize ovarian cancer cells to sub-toxic concentrations of belinostat. Interestingly, the combination of belinostat with the BH3-mimetic ABT-737, that inhibits Bcl-xL, induced massive apoptosis. Moreover, Mcl-1 direct or indirect inhibition was also very efficient to sensitize ovarian cancer cells to belinostat. These results suggest that belinostat, alone or in association with pharmacological molecules that inhibit Mcl-1 or Bcl-xL, represents a promising approach for the treatment of chemoresistant ovarian cancers. Citation Format: Charlène Duboc, Edwige Abeilard, Anne Sophie Voisin-Chiret, Pascal Gauduchon, Laurent Poulain, Marie Villedieu. The sensitivity of ovarian cancer cells to the HDAC inhibitor belinostat is improved by inhibiting Bcl-xL or Mcl-1 anti-apoptotic proteins [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1921.

Objective. Emergence of chemoresistance in the course of treatments with platinum drugs remains a major hurdle to ovarian carcinoma therapy. We have previously shown that acquisition of cisplatin resistance by OAW42-R ovarian carcinoma cells was associated with the loss of ERK activation in response to cisplatin. To try to sensitize this cell line by restoring ERK activation, we tested a new synthetic compound, 2[[3-(2,3-dichlorophenoxy)propyl]amino]ethanol (2,3-DCPE), which was described to induce ERK activation and to display anticancer properties. Methods. We treated four ovarian carcinoma cell lines with 2,3-DCPE, alone or combined with cisplatin. We characterized its effects on apoptosis induction and proliferation and correlated them with molecular modulations. Results. We showed that 2,3-DCPE induced cell death and ERK phosphorylation in a time- and concentration-dependent manner in OAW42-R cells. 2,3-DCPE-triggered apoptosis was also associated with the inhibition of Bcl-2 expression and, to a less extent, with that of Bcl-x L . Treatment with 2,3-DCPE also elicited a strong G0/G1 cell cycle arrest, accompanied with p21 WAF1/CIP1 up-regulation. All of these effects revealed to be irreversible. Moreover, 2,3-DCPE exerted a cytostatic effect on OAW42, IGROV1-R10 and SKOV3 ovarian carcinoma cells, the sensitivity to 2,3-DCPE appearing in particular linked with a low basal level of P-ERK. Finally, we showed that 2,3-DCPE increased the cytotoxic effect of cisplatin in OAW42-R resistant cells. Conclusion. Our results emphasized the potential interest of 2,3-DCPE, used alone or combined with cisplatin, for ovarian carcinoma treatment. The absence of basal P-ERK may constitute a predictive marker of response to this novel therapy.

Objective. Recurrence and cisplatin resistance that progressively develops in the course of treatments are major impediments in ovarian cancer therapy. We investigated the involvement of alterations of different signaling pathways in this acquired chemoresistance. Methods. We studied the activation of these pathways in a model of progressive acquisition of resistance that we established, by discontinuously exposing a sensitive ovarian carcinoma cell line, OAW42, to increasing concentrations of cisplatin. Results. OAW42-T1 and -T2 variants, which emerged after the first two treatments of OAW42 cells with 5 μg/ml cisplatin, showed enhanced but transient resistance. OAW42-R cells, obtained following successive reiterations of the treatment, displayed both a stronger resistance to cisplatin-induced apoptosis and an increased capacity to recover a normal proliferation after treatment. The measurement of DNA adducts demonstrated that the mechanisms leading to a decreased DNA platination could not explain the level of resistance of OAW42-R cells. The simultaneous study of activation pattern of key proteins of different signaling pathways revealed that cisplatin induced both activation of ERK and p38 and inhibition of P-FAK in the sensitive cells, whereas it progressively failed to elicit such a response in the resistant variants. In contrast, STAT3 and Akt did not seem to be involved in the acquired chemoresistance in our model. Conclusions. Our results suggested that emergence of chemoresistance was accompanied with the progressive loss of ERK and p38 activation and with the maintenance of FAK activation in response to cisplatin, and they demonstrated that these alterations were early events in the course of treatments.

Introduction Increasing evidence indicates that microRNAs (miRNAs) are important players in oncogenesis. Considering the widespread use of aromatase inhibitors (AIs) in endocrine therapy as a first-line treatment for postmenopausal estrogen receptor α–positive breast cancer patients, identifying deregulated expression levels of miRNAs in association with AI resistance is of utmost importance. Methods To gain further insight into the molecular mechanisms underlying the AI resistance, we performed miRNA microarray experiments using a new model of acquired resistance to letrozole (Res-Let cells), obtained by long-term exposure of aromatase-overexpressing MCF-7 cells (MCF-7aro cells) to letrozole, and a model of acquired anastrozole resistance (Res-Ana cells). Three miRNAs (miR-125b, miR-205 and miR-424) similarly deregulated in both AI-resistant cell lines were then investigated in terms of their functional role in AI resistance development and breast cancer cell aggressiveness and their clinical relevance using a cohort of 65 primary breast tumor samples. Results We identified the deregulated expression of 33 miRNAs in Res-Let cells and of 18 miRNAs in Res-Ana cells compared with the sensitive MCF-7aro cell line. The top-ranked Kyoto Encyclopedia of Genes and Genomes pathways delineated by both miRNA signatures converged on the AKT/mTOR pathway, which was found to be constitutively activated in both AI-resistant cell lines. We report for the first time, to our knowledge, that ectopic overexpression of either miR-125b or miR-205, or the silencing of miR-424 expression, in the sensitive MCF-7aro cell line was sufficient to confer resistance to letrozole and anastrozole, to target and activate the AKT/mTOR pathway and to increase the formation capacity of stem-like and tumor-initiating cells possessing self-renewing properties. Increasing miR-125b expression levels was also sufficient to confer estrogen-independent growth properties to the sensitive MCF-7aro cell line. We also found that elevated miR-125b expression levels were a novel marker for poor prognosis in breast cancer and that targeting miR-125b in Res-Let cells overcame letrozole resistance. Conclusion This study highlights that acquisition of specific deregulated miRNAs is a newly discovered alternative mechanism developed by AI-resistant breast cancer cells to achieve constitutive activation of the AKT/mTOR pathway and to develop AI resistance. It also highlights that miR-125b is a new biomarker of poor prognosis and a candidate therapeutic target in AI-resistant breast cancers. Electronic supplementary material The online version of this article (doi:10.1186/s13058-015-0515-1) contains supplementary material, which is available to authorized users.

We previously showed that Bcl-xL and Mcl-1 cooperatively protect platinum-resistant ovarian cancer cells from apoptosis. Here we assessed the anticancer potential of combining ABT-737-induced inhibition of Bcl-xL with Mcl-1 inhibition via PI3K/Akt/mTOR pathway disruption using NVP-BEZ235. NVP-BEZ235 inhibited cell proliferation without inducing apoptosis. It strongly repressed Mcl-1 expression and induced Puma expression in both cell lines tested while differentially modulating Bim between the two. Interestingly, NVP-BEZ235 efficiently sensitized ovarian carcinoma cells to ABT-737, provided that Bim expression was induced. Moreover, inhibiting the ERK1/2 pathway restored Bim expression and sensitized low Bim-expressing cancer cells to the BEZ235/ABT-737 treatment.

Acquisition of resistance to aromatase inhibitors (AIs) remains a major drawback in the treatment of estrogen receptor alpha (ERα)-positive breast cancers. The Res-Ana cells, a new model of acquired resistance to anastrozole, were established by long-term exposure of aromatase-overexpressing MCF-7 cells to this drug. These resistant cells developed ER-independent mechanisms of resistance and decreased sensitivity to the AI letrozole or to ERα antagonists. They also displayed a constitutive activation of the PI3K/Akt/mTOR pathway and a deregulated expression of several ErbB receptors. An observed increase in the phospho-Akt/Akt ratio between primary and matched recurrent breast tumors of patients who relapsed under anastrozole adjuvant therapy also argued for a pivotal role of the Akt pathway in acquired resistance to anastrozole. Ectopic overexpression of constitutively active Akt1 in control cells was sufficient to induce de novo resistance to anastrozole. Strikingly, combining anastrozole with the highly selective and allosteric Akt inhibitor MK-2206 or with the mTOR inhibitor rapamycin increased sensitivity to this AI in the control cells and was sufficient to overcome resistance and restore sensitivity to endocrine therapy in the resistant cells. Our findings lead to us proposing a model of anastrozole-acquired resistance based on the selection of cancer-initiating-like cells possessing self-renewing properties, intrinsic resistance to anastrozole and sensitivity to MK-2206. Altogether, our work demonstrated that the Akt/mTOR pathway plays a key role in resistance to anastrozole and that combining anastrozole with Akt/mTOR pathway inhibitors represents a promising strategy in the clinical management of hormone-dependent breast cancer patients.

Background ZNF217 is a candidate oncogene located at 20q13, a chromosomal region frequently amplified in breast cancers. The precise mechanisms involved in ZNF217 pro-survival function are currently unknown, and utmost importance is given to deciphering the role of ZNF217 in cancer therapy response. Results We provide evidence that stable overexpression of ZNF217 in MDA-MB-231 breast cancer cells conferred resistance to paclitaxel, stimulated cell proliferation in vitro associated with aberrant expression of several cyclins, and increased tumor growth in mouse xenograft models. Conversely, siRNA-mediated silencing of ZNF217 expression in MCF7 breast cancer cells, which possess high endogenous levels of ZNF217, led to decreased cell proliferation and increased sensitivity to paclitaxel. The paclitaxel resistance developed by ZNF217-overexpressing MDA-MB-231 cells was not mediated by the ABCB1/PgP transporter. However, ZNF217 was able to counteract the apoptotic signals mediated by paclitaxel as a consequence of alterations in the intrinsic apoptotic pathway through constitutive deregulation of the balance of Bcl-2 family proteins. Interestingly, ZNF217 expression levels were correlated with the oncogenic kinase Aurora-A expression levels, as ZNF217 overexpression led to increased expression of the Aurora-A protein, whereas ZNF217 silencing was associated with low Aurora-A expression levels. We showed that a potent Aurora-A kinase inhibitor was able to reverse paclitaxel resistance in the ZNF217-overexpressing cells. Conclusion Altogether, these data suggest that ZNF217 might play an important role in breast neoplastic progression and chemoresistance, and that Aurora-A might be involved in ZNF217-mediated effects.

In ovarian carcinomas, recurrence and acquired chemoresistance are the first leading causes of therapeutic failure and are responsible for the poor overall survival rate. Cisplatin exposure of sensitive cells has been previously associated with a down-regulation of Bcl-X(L) expression and apoptosis, whereas recurrence was systematically observed when Bcl-X(L) expression was maintained. Bcl-X(L) down-regulation could thus constitute an interesting chemosensitizing strategy. We showed that a Bcl-X(L)targeted RNA interference strategy efficiently sensitized chemoresistant ovarian carcinoma cells to cisplatin, but some of them were still able to re-proliferate. Considering the possible cooperation between Bcl-X(L)and MCL-1, we investigated the possibility to avoid recurrence in vitro using a multi-targeted RNAi strategy directed against these two anti-apoptotic proteins. We showed that their concomitant inhibition lead to massive apoptosis in absence of cisplatin, this multi-targeted RNAi approach being much more efficient than conventional chemotherapy. We thus demonstrated that Bcl-X(L) and MCL-1 cooperate to constitute together a strong molecular "bolt", which elimination could be sufficient to allow chemoresistant ovarian carcinoma cells apoptosis. Moreover, we demonstrated that in presence of a low concentration of cisplatin, the concomitant down-regulation of Bcl-X(L) and MCL-1 allowed a complete annihilation of tumour cells population thus avoiding subsequent recurrence in vitro in cell lines highly refractory to any type of conventional chemotherapy. Therefore, Bcl-X(L) and MCL-1 targeted strategies could constitute an efficient therapeutic tool for the treatment of chemoresistant ovarian carcinoma, in association with conventional chemotherapy.

2-Deoxy-D-glucose (2-DG) is an analog of glucose that is preferentially captured by tumors and is accumulated in transformed cells, because the phosphorylated molecule (2-DG-6P) cannot be metabolized or diffused outside the cells. Targeted with a fluorine atom, 18F-DG is currently used to visualize malignant tumors (PET scan). Although cancer cells have been reported to be strongly dependent on glycolysis (Warburg effect), very few reports have studied the inhibitory effects of 2-DG on cancer.Our objective was to study, in a large panel of human malignant cells of various origins (ovarian, squamous, cerebral, hepatic, colonic and mesothelial), if the inhibitory activity of 2DG against tumor growth could be considered a general phenomenon and to determine its effect on the cell cycle.Four types of response in the different cell lines were observed when cells were cultured in the presence of 2-DG (5 mM) continuous exposure: proliferation slow down; proliferation arrest without signs of apoptosis; strong cell cycle arrest accompanied by moderate apoptosis induction; massive apoptosis.2-DG appears as an interesting new therapeutic agent against cancer in vitro, and should be tested in in vivo studies.

Objective Recurrence and subsequent acquired chemoresistance to platinum-based treatments constitute major hurdles to ovarian carcinoma therapy. Our objective was to examine the involvement of Bcl-x L anti-apoptotic protein in resistance to cisplatin. Methods We described the effect of cisplatin on cell cycle and apoptosis induction in sensitive (IGROV1 and OAW42) and resistant (IGROV1-R10 and SKOV3) ovarian carcinoma cell lines. We correlated it with Bcl-x L mRNA and protein expression after exposure to cisplatin. We then used bcl - x S gene transfer to impede Bcl-x L activity. Results Our study showed that Bcl-x L basal expression was high in both sensitive and resistant cell lines, as well as in all the studied ovarian tumor samples. Thus, Bcl-x L basal expression could not allow to predict sensitivity. Wondering whether variation of Bcl-x L level in response to cisplatin could be a better determinant of sensitivity, we investigated the expression of this protein in the cell lines after treatment. Cisplatin-induced down-regulation of Bcl-x L was strictly associated with apoptosis and absence of recurrence in vitro. Conversely, the maintenance of Bcl-x L expression in response to cisplatin appeared as a sine qua non condition to escape to treatment. To try to sensitize SKOV3 cells by impeding anti-apoptotic activity of Bcl-x L , we transfected bcl-x S gene in these cells. Bcl-x S exogenous expression was only slightly cytotoxic on its own, but highly sensitized SKOV3 resistant cells to cisplatin-induced apoptosis, and delayed recurrence. Conclusion This work thus provides one more argument to put Bcl-x L forward as a pertinent target of inhibition to overcome chemoresistance of epithelial ovarian carcinoma.

Colorectal cancer is now the second (or first depending on sex) source of death before age 70. This cancer is a particularly interesting model because it has long been proven that its incidence is largely due to environmental factors. It is also one of the only cancers to be systematically screened today. This pharmacy thesis details all the techniques used for this screening, from biological tests to all the imaging techniques. Also it describe the different treatments and treatment protocols for colorectal cancer (CRC). A second part details the energy metabolism of CRC and its implication in tumor development. The focus is particularly made on dicarbonyl stress (DS) as a side product of glycolysis and mainly represented by methylglyoxal. The impact of this stress is put side to side with the mutation of the KRAS gene very frequently present in CRC at advanced stages. This mutation constitutes a obstacle to the targeted therapies currently used, and a possible sensitivity of KRAS mutated CRCs to alterations of DS could constitute an interesting avenue for circumventing the therapeutic obstacle which the KRAS mutation constitutes today. The results obtained during a 6-month research internship carried out as part of a Master 2 within the Laboratory for Research on Metastases in Liège are presented and analyzed at the end of the document as an illustration of the potential interest of DS as a lever to control the survival of mutated KRAS CCR tumor cells.; Le cancer colorectal constitue aujourd'hui la deuxième (ou première selon le sexe) source de décès avant 70 ans. Ce cancer constitue un modèle particulièrement intéressant car il est depuis longtemps avéré que son incidence est largement due à des facteurs environnementaux. Il est également l'un des seuls cancers à aujourd'hui faire l'objet d'un dépistage systématique. Cette thèse d'exercice fait le point sur l'ensemble des techniques utilisées pour ce dépistage, des tests biologiques aux différentes techniques d'imagerie, et sur les différents traitements et protocoles de soin du cancer colorectal (CCR). Une seconde partie détaille le métabolisme énergétique du CCR et son implication dans le développement tumoral. Le focus est plus particulièrement fait sur le stress dicarbonyle (SD) comme produit annexe de la glycolyse et majoritairement représenté par le methylglyoxal. L'impact de ce stress est mis en regard de la mutation du gène KRAS très fréquemment présente dans les CCR à des stades avancés. Cette mutation constituent un frein aux thérapies ciblées habituellement utilisées, et une éventuelle sensibilité des CCR mutés KRAS aux altérations du SD pourrait constituer une piste intéressante pour contourner l'obstacle thérapeutique que constitue aujourd'hui la mutation de KRAS. Les résultats obtenus au cours d'un stage de recherche de 6 mois effectué dans le cadre d'un Master 2 au sein du Laboratoire de recherche sur les métastases à Liège sont présentés et analysés à la fin du document comme illustration de l'intérêt potentiel du SD comme levier pour contrôler la survie des cellules tumorales de CCR KRAS mutés.

In a context of more and more ambulatory care for patients suffering from cancer, the oral antineoplastic therapies have grown significantly in the recent years. At present, 20 to 25% of these antineoplastic treatments in studies are oral administration. One of the reasons of this choice is to simplify ambulatory care of the patients to improve their quality of life and comfort. These treatments lengthen the response time and making cancer as a chronic disease in an increasing number of indications. Even if these therapies offer many advantages, they show inconvenience as well: the occurrence of side effects at home, specific handling and administration and also risk of nonadherence. The pharmacist dispenses these therapies and definitely plays a key role for the administration, the onset of side effects and the adherence of the treatment. The adherence has been revealed as similar as other chronic diseases, namely 50%. A poor observance leads to a loss of chance of recovery for the patient. Many factors will influence the therapeutic adherence, they can be categorized into five categories: therapy, patient, disease, healthcare system and socio-economic characteristics. Strategies must be developed to improve the adherence. There are tools which can help the patient: the therapy action notebook and the dose plan. However the development of the therapeutic patient education seems to be an essential work to minimise the risks of the therapy and maximise its accomplishment.; Dans un contexte de prise en charge de plus en plus ambulatoire des patients atteints de cancer, les thérapies anticancéreuses orales ont connu un essor important ces dernières années. Actuellement, 20 à 25 % des traitements anticancéreux en étude sont administrés par voie orale. Une des raisons du choix de cette voie d’administration est de simplifier la prise en charge des patients dans le but d’améliorer leur qualité de vie et leur confort. Ces traitements allongent le temps de réponse faisant du cancer une pathologie de plus en plus chronique dans un nombre croissant d’indication. Même si ces thérapies offrent de nombreux avantages elles présentent aussi des inconvénients : survenue d’effets indésirables au domicile du patient, manipulation et administration particulière et risque de non observance. Le pharmacien d’officine dispense ces thérapies, il va jouer un rôle essentiel dans la gestion du traitement, la survenue des effets indésirables et l’observance du traitement. L’observance de ces thérapies s’est révélée similaire à celle des autres traitements des pathologies chroniques à savoir 50 %. La mauvaise observance entraîne notamment une perte de chance de guérison pour le patient. Un certain nombre de facteurs vont influencer l’adhésion thérapeutique, ils peuvent être classés en cinq catégories : la thérapie, le patient, la maladie, le système de santé et les caractéristiques socio-économiques. Des stratégies doivent être développées afin d’améliorer l’adhésion thérapeutique. Des outils comme le carnet de suivi et le plan de prise peuvent aider le patient à suivre son traitement. Néanmoins, le développement de l’éducation thérapeutique du patient semble incontournable afin de minimiser les risques du traitement et d’optimiser sa réussite.