Nox2-deficient Tregs improve heart transplant outcomes via their increased graft recruitment and enhanced potency.

Nox2 is a ROS-generating enzyme, deficiency of which increases suppression by Tregs in vitro and in an in vivo model of cardiac remodelling. Since Tregs have emerged as a candidate therapy in autoimmunity and transplantation, we hypothesised that Nox2 deficiency in Tregs in recipient mice may improve outcomes in a heart transplant model. A novel B6129 mouse model with Treg-targeted Nox2 deletion (Nox2fl/flFoxP3Cre+) was generated and transplanted with hearts from CB6F1 donors. As compared to littermate controls, Nox2fl/flFoxP3Cre+ mice had lower plasma levels of alloantibodies and troponin-I, reduced levels of IFN-γ in heart allograft homogenates and diminished cardiomyocyte necrosis and allograft fibrosis. Single cell analyses of allografts revealed higher absolute numbers of Tregs and lower CD8+ T cell infiltration in Nox2-deficient recipients compared to Nox2-replete mice. Mechanistically, in addition to a greater suppression of CD8+CD25- T effector cell proliferation and IFN-γ production, Nox2-deficient Tregs expressed higher levels of CCR4 and CCR8, driving cell migration to allografts; this was associated with increased expression of miR214-3p. These data indicate that Nox2 deletion in Tregs enhances their suppressive ability and migration to heart allografts. Therefore, Nox2 inhibition in Tregs may be a useful approach to improve their therapeutic efficacy

Medecine personalisée et recherche des biomarqueurs à une thérapie ciblée dans le cancer du sein : L'exemple des inhibiteurs CDK4/6

L’avènement du séquençage haut débit a mis en lumière l’hétérogénéité des cancers du sein qui peuvent être groupés en fonction d’altérations moléculaires spécifiques qui sont pour certaines à la base de thérapies ciblées dans le cadre de la médecine personnalisée. Néanmoins de nombreuses complications viennent compromettre le succès thérapeutique de ces approches. En effet, l’une des thérapies ciblées les plus efficaces développées récemment, les inhibiteurs de CDK4/6, sont prescrits chez tous les patients HR+/HER aux stades avancés de la maladie alors même qu’aucun biomarqueur n’a pour l’heure été identifié. Ainsi les données pharmacodynamiques et les marqueurs pronostics font cruellement défaut pour ces patients. Afin d’identifier de tels marqueurs, nous avons conduit une étude clinique « fenêtre d’opportunité » incluant 100 patients à un stade précoce de la maladie. L’analyse en IHC et les études de profilage expression génomique des tumeurs a permis de montrer qu’une courte exposition au palbociclib, un inhibiteur de CDK4/6 induisait un arrêt du cycle cellulaire révélé par une diminution de phospho-Rb et Ki67. Cette corrélation entre diminution du phospho-Rb et la diminution de la prolifération suggère d’ailleurs son utilisation comme biomarqueur de la réponse au palbociclib. Une analyse sur puce à cDNA a permis d’identifier un panel de gènes régulateurs de la prolifération (MKI67, TOP2A, BIRC5) et de la machinerie du cycle cellulaire (PLK1, FOXM1) modulé par le palbociclib. Bien que nous n’ayons pu identifier de marqueurs de résistance au palbociclib en condition basale, nous avons observé des niveaux élevés de CCNE chez les patients traités résistants au palbociclib. Cette donnée a été confirmée chez les patients aux stades avancés de la maladie dans le cadre d’une étude menée en collaboration avec un groupe britannique. D’autres données obtenues en collaboration avec une équipe de l’université Vanderbilt, ont par ailleurs permis de suggérer une contribution des inhibiteurs de CDK4/6 à la réversion de la résistances aux hormonothérapie en inhibant l’expression les gènes cibles du facteur de transcription E2F4. Pour finir, les activités biologiques et cliniques des différents inhibiteurs de CDK4/6 disponibles n’étant pas exactement identiques, un second essai clinique « fenêtre d’opportunité » nous a permis de mettre en évidence un profil de toxicité distinct de l’abemaciclib et de montrer que, contrairement au palbociclib, l’abemaciclib montre une efficacité lorsqu’il est utilisé seul. Une des explications possible de ces différentes activités serait un spectre d’action de l’abemaciclib ciblant plus efficacement la CDK9, même si l’impact clinique associé n’a pas été examiné en détail et qu’une comparaison rigoureuse de l’activité de ces deux inhibiteurs de CDK n’a pas encore été réalisée.New sequencing methods have revealed that breast cancer is heterogeneous and characterized by different subgroups harboring specific molecular alterations for which targeted therapies have been developed with the hope of implementing personalized medicine. However, this approach has been proven far too simplistic. Indeed, one of the latest and more efficient targeted therapies to be developed in breast cancer are the CDK4/6 inhibitors, approved for all HR+/HER2- advanced breast cancers. So far, and despite the significant number of patients treated with these drugs, no biomarkers of efficacy have been identified and no clear information about pharmacodynamics have been presented. In order to determine biomarkers of efficacy and pharmacodynamics of palbociclib, the first approved CDK4/6 inhibitor, we conducted a window of opportunity clinical trial in 100 early breast cancer patients. IHC and GE analyses identified that a short period of palbociclib treatment was able to induce cell cycle arrest as determined by decreased phospho-Rb expression and this was accompanied by a profound decrease in proliferation as determined by lnKi67<1 after treatment, with a correlation between changes in proliferation and changes in phospho-Rb, suggesting that early decrease in phospho-Rb could be linked to sensitivity to this drug. Microarray analyses identified that palbociclib modulates genes involved in proliferation (such as MKI67, TOP2A, BIRC5) and cell cycle (such as PLK1, FOXM1). Despite we were not able to identify baseline biomarkers of resistance to this treatment, we observed that levels of CCNE remained high in palbociclib-resistant patients. This finding was further validated in collaboration with an-UK research group who had conducted biomarker research in the advanced setting. Moreover, our data helped also to determine in a different collaboration with Vanderbilt University, that CDK/6 inhibitors might contribute to reverse endocrine resistance generated by activation of genes linked to the E2F4 transcription factor. Finally, as preclinical and clinical data suggest some diversity between different CDK4/6 inhibitors, we decided to conduct a second window of opportunity trial with a second CDK4/6 inhibitor, abemaciclib, who has shown different toxicity profile and, unlike palbociclib, significant efficacy as single-agent. One suggested explanation could be due to a higher impact on CDK9, although its clinical impact has not been determined and no comparison between these two drugs has been performed

Triple-negative breast cancer: are we making headway at least?

The so-called triple-negative breast cancer, as defined by tumors that lack estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (HER2) overexpression, has generated growing interest in recent years despite representing less than 20% of all breast cancers. These tumors constitute an important clinical challenge, as they do not respond to endocrine treatment and other targeted therapies. As a group they harbor an aggressive clinical phenotype with early development of visceral metastases and a poor long-term prognosis. While chemotherapy remains effective in triple-negative disease, research continues to further identify potential new targets based on phenotypical and molecular characteristics of these tumors. In this respect, the presence of a higher expression of different biomarkers including epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptor and Akt activation has led to a proliferation of clinical trials assessing the role of inhibitors to these pathways in triple-negative tumors. Moreover, the described overlap between triple-negative and basal-like tumors, and the similarities with tumors arising in the BRCA1 mutation carriers has offered potential therapeutic avenues for patients with these cancers including poly (ADP-ribose) polymerase inhibitors and a focus on a higher sensitivity to alkylating chemotherapy agents. Results from these trials have shown some benefit in small subgroups of patients, even in single-agent therapy, which reflects the heterogeneity of triple-negative breast cancer and highlights the need for a further subclassification of these types of tumors for better prognosis identification and treatment individualization

Efficacy of antiandrogens in androgen receptor-positive triple-negative metastatic breast cancer: Real-life data

Antiandrogens (AA) have been tested in clinical trials in androgen receptor (AR) + triple-negative breast cancer (TNBC). We aim to assess the clinical benefit rate (CBR) of AA in real life.The primary end-point was CBR at 6 months. Twenty-four patients were assessable and received: abiraterone acetate (62 %), enzalutamide (8 %) and bicalutamide (30 %). CBR at 6 months was 29 % (7/24) with 2 CR, 3 PR and 2 SD. Four patients had a clinical benefit >12 months. Real-life efficacy of AA use in metastatic AR + TNBC are in line with data from published trials

Association between the nuclear to cytoplasmic ratio of p27 and the efficacy of adjuvant polychemotherapy in early breast cancer

Background: The purpose of this study was to evaluate the prognostic and predictive value of p27 expression in patients with early breast cancer. Patients and methods: Quantitative immunofluorescence assays for p27 were done on a tissue microarray that included 823 samples from patients randomized between anthracycline-based chemotherapy and no chemotherapy. Quantification of p27 was done using the AQUA® system (HistoRx, Inc. Branford, CT). Both p27 nuclear expression and the nuclear to cytoplasmic ratio were assessed. Results: Nuclear p27 expression was not predictive for the efficacy of anthracycline-based chemotherapy [adjusted P = 0.18 for disease-free survival (DFS)] nor prognostic [95% confidence interval (CI) 0.99-1.01, P = 0.49]. However, p27 nuclear/cytoplasmic ratio was predictive for the efficacy of adjuvant chemotherapy (adjusted P = 0.016 DFS). The adjusted hazard ratio (HR) for relapse associated with adjuvant chemotherapy was 0.56 (95% CI 0.37-0.84, P = 0.005) and 1.06 (95% CI 0.76-1.47, P = 0.74) for patients with high and low nuclear/cytoplasmic ratio, respectively. p27 N/C ratio was prognostic in patients treated with chemotherapy (HR for relapse or death for a 1 unit increase in p27 N/C ratio was 0.30, 95% CI 0.12-0.77) but not in the untreated arm (HR for relapse or death was 1.27, 95% CI 0.58-2.8). Conclusions: This study did not confirm the role of p27 nuclear expression as a prognostic parameter. However, the p27 nuclear/cytoplasmic ratio was predictive in patients treated with anthracycline-based chemotherapy. © The Author 2012. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cancer of the Breast

info:eu-repo/semantics/publishe

Polymorphisms of CYP19A1 and response to aromatase inhibitors in metastatic breast cancer patients

Single nucleotide polymorphisms (SNPs) in the gene encoding aromatase (CYP19A1) have been associated with differential benefit from letrozole treatment in metastatic breast cancer (mBC) patients, but validation is lacking. The aim was to investigate whether polymorphic variation of CYP19A1 and enzymes involved in estrogen and aromatase inhibitors (AIs) metabolism are associated with efficacy of AIs. 308 Women with estrogen-receptor-positive metastatic mBC treated with a third-generation AI were identified retrospectively. DNA was extracted from archival formalin-fixed paraffin embedded tumors and genotyped for 71 variants in 16 candidate genes, including CYP19A1. Time to treatment failure (TTF) was significantly improved in patients carrying the minor (T) allele of rs4775936 when compared to patients with the reference allele [HR = 0.79 per T allele (0.66-0.95); P = 0.012]. Patients with > 7 TTTA repeats on either allele of CYP19A1 intron 4 had a lower risk of failure than those with a smaller repeat size [HR = 0.84 per > 7 TTTA repeats (0.7-0.99); P = 0.04]. However, importantly in multivariate analysis, adjusting for the number of disease sites; disease-free interval from diagnosis to first recurrence, grade at diagnosis and first recurrence type neither variant maintained independent predictive significance. None of the 56 SNPs analyzed as an exploratory set showed significant association with TTF. Variants in CYP19A1 or other selected genes associated with AI metabolism were not independently associated with improved AI efficacy and emphasize the importance in pharmacogenetic studies of considering genetic biomarkers in the context of relevant prognostic factors