Genomic profiling of mycosis fungoides identifies patients at high risk of disease progression.

ABSTRACT: Mycosis fungoides (MF) is the most prevalent primary cutaneous T-cell lymphoma, with an indolent or aggressive course and poor survival. The pathogenesis of MF remains unclear, and prognostic factors in the early stages are not well established. Here, we characterized the most recurrent genomic alterations using whole-exome sequencing of 67 samples from 48 patients from Lille University Hospital (France), including 18 sequential samples drawn across stages of the malignancy. Genomic data were analyzed on the Broad Institute's Terra bioinformatics platform. We found that gain7q, gain10p15.1 (IL2RA and IL15RA), del10p11.22 (ZEB1), or mutations in JUNB and TET2 are associated with high-risk disease stages. Furthermore, gain7q, gain10p15.1 (IL2RA and IL15RA), del10p11.22 (ZEB1), and del6q16.3 (TNFAIP3) are coupled with shorter survival. Del6q16.3 (TNFAIP3) was a risk factor for progression in patients at low risk. By analyzing the clonal heterogeneity and the clonal evolution of the cohort, we defined different phylogenetic pathways of the disease with acquisition of JUNB, gain10p15.1 (IL2RA and IL15RA), or del12p13.1 (CDKN1B) at progression. These results establish the genomics and clonality of MF and identify potential patients at risk of progression, independent of their clinical stage.

[Lethal AML? Calcium signalling to the rescue!] / LAM fatale ? - La signalisation calcique à la rescousse !

Acute myeloid leukemia (AML) is characterized by genetic aberrations in hematopoietic precursors of the myeloid lineage which lead to their defective maturation/function. While intensive chemotherapy protocols result in complete remission in 50 % to 80 % of AML patients, relapse occurs in the majority of cases. While calcium signalling is a well-known contributor to cancer hallmarks, few AML related studies have focused on relevant calcium targets. Our purpose here is to highlight calcium channels and associated signalling pathways involved in AML, in order to promote the development of treatments specifically targeting these pathways.

Title: LAM fatale ? - La signalisation calcique à la rescousse ! Abstract: La leucémie aiguë myéloïde (LAM) est une hémopathie maligne caractérisée par des aberrations génétiques de certains précurseurs hématopoïétiques de la lignée myéloïde qui entraînent un défaut de maturation et/ou de fonctionnement. Malgré une chimiothérapie intensive entraînant une rémission complète chez 50 à 80 % des patients, la rechute survient dans la majorité des cas. Bien que la signalisation calcique soit bien décrite dans les cancers solides, l'étude de cibles pertinentes dépendant du calcium a retenu peu d'attention dans la LAM jusqu'à aujourd'hui. L'objectif de cette revue est d'offrir une piste de réflexion sur l'identification de canaux calciques spécifiques et de voies de signalisation associées impliquées dans la LAM, et ainsi de promouvoir la recherche de nouvelles approches thérapeutiques efficaces ciblant spécifiquement ces voies.

Preclinical Study of Radiation on Fat Flap Regeneration under Tissue-engineering Chamber: Potential Consequences for Breast Reconstruction.

Use of a tissue-engineering chamber (TEC) for growth of fat flap is a promising approach for breast reconstruction. Here, we evaluated in a preclinical model the effects of radiation on adipose tissue growth either before or after 3D-printed bioresorbable TEC implantation. Methods: Twenty-eight female Wistar rats were distributed into three groups: TEC implantation as nonirradiated controls (G1), TEC insertion followed by irradiation 3 weeks later (G2), and irradiation 6 weeks before TEC insertion (G3). G2 and G3 received 33.3 Gy in nine sessions of 3.7 Gy. Growth of the fat flap was monitored via magnetic resonance imaging. At 6 months after implantation, fat flaps and TECs were harvested for analysis. Results: Irradiation did not alter the physicochemical features of poly(lactic-co-glycolic acid)-based TECs. Compared with G1, fat flap growth was significantly reduced by 1.6 times in irradiated G2 and G3 conditions. In G2 and G3, fat flaps consisted of mature viable adipocytes sustained by CD31+ vascular cells. However, 37% (3 of 8) of the G2 irradiated adipose tissues presented a disorganized architecture invaded by connective tissues with inflammatory CD68 + cells, and the presence of fibrosis was observed. Conclusions: Overall, this preclinical study does not reveal any major obstacle to the use of TEC in a radiotherapy context. Although irradiation reduces the growth of fat flap under the TEC by reducing adipogenesis and inducing inconsistent fibrosis, it does not impact flap survival and vascularization. These elements must be taken into account if radiotherapy is proposed before or after TEC-based breast reconstruction.

Involvement of ORAI1/SOCE in Human AML Cell Lines and Primary Cells According to ABCB1 Activity, LSC Compartment and Potential Resistance to Ara-C Exposure.

Acute myeloid leukemia (AML) is a hematological malignancy with a high risk of relapse. This issue is associated with the development of mechanisms leading to drug resistance that are not yet fully understood. In this context, we previously showed the clinical significance of the ATP binding cassette subfamily B-member 1 (ABCB1) in AML patients, namely its association with stemness markers and an overall worth prognosis. Calcium signaling dysregulations affect numerous cellular functions and are associated with the development of the hallmarks of cancer. However, in AML, calcium-dependent signaling pathways remain poorly investigated. With this study, we show the involvement of the ORAI1 calcium channel in store-operated calcium entry (SOCE), the main calcium entry pathway in non-excitable cells, in two representative human AML cell lines (KG1 and U937) and in primary cells isolated from patients. Moreover, our data suggest that in these models, SOCE varies according to the differentiation status, ABCB1 activity level and leukemic stem cell (LSC) proportion. Finally, we present evidence that ORAI1 expression and SOCE amplitude are modulated during the establishment of an apoptosis resistance phenotype elicited by the chemotherapeutic drug Ara-C. Our results therefore suggest ORAI1/SOCE as potential markers of AML progression and drug resistance apparition.

Put in a "Ca2+ll" to Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a clonal disorder characterized by genetic aberrations in myeloid primitive cells (blasts) which lead to their defective maturation/function and their proliferation in the bone marrow (BM) and blood of affected individuals. Current intensive chemotherapy protocols result in complete remission in 50% to 80% of AML patients depending on their age and the AML type involved. While alterations in calcium signaling have been extensively studied in solid tumors, little is known about the role of calcium in most hematologic malignancies, including AML. Our purpose with this review is to raise awareness about this issue and to present (i) the role of calcium signaling in AML cell proliferation and differentiation and in the quiescence of hematopoietic stem cells; (ii) the interplay between mitochondria, metabolism, and oxidative stress; (iii) the effect of the BM microenvironment on AML cell fate; and finally (iv) the mechanism by which chemotherapeutic treatments modify calcium homeostasis in AML cells.

Antimetabolic cooperativity with the clinically approved l-asparaginase and tyrosine kinase inhibitors to eradicate CML stem cells.

OBJECTIVE: Long-term treatment with tyrosine kinase inhibitors (TKI) represents an effective cure for chronic myeloid leukemia (CML) patients and discontinuation of TKI therapy is now proposed to patient with deep molecular responses. However, evidence demonstrating that TKI are unable to fully eradicate dormant leukemic stem cells (LSC) indicate that new therapeutic strategies are needed to control LSC and to prevent relapse. In this study we investigated the metabolic pathways responsible for CML surviving to imatinib exposure and its potential therapeutic utility to improve the efficacy of TKI against stem-like CML cells. METHODS: Using complementary cell-based techniques, metabolism was characterized in a large panel of BCR-ABL+ cell lines as well as primary CD34+ stem-like cells from CML patients exposed to TKI and L-Asparaginases. Colony forming cell (CFC) assay and flow cytometry were used to identify CML progenitor and stem like-cells. Preclinical models of leukemia dormancy were used to test the effect of treatments. RESULTS: Although TKI suppressed glycolysis, compensatory glutamine-dependent mitochondrial oxidation supported ATP synthesis and CML cell survival. Glutamine metabolism was inhibited by L-asparaginases such as Kidrolase or Erwinase without inducing predominant CML cell death. However, clinically relevant concentrations of TKI render CML cells susceptible to Kidrolase. The combination of TKI with Lasparaginase reactivates the intinsic apoptotic pathway leading to efficient CML cell death. CONCLUSION: Targeting glutamine metabolism with the FDA-approved drug, Kidrolase in combination with TKI that suppress glycolysis represents an effective and widely applicable therapeutic strategy for eradicating stem-like CML cells.

p65/RelA NF-κB fragments generated by RIPK3 activity regulate tumorigenicity, cell metabolism, and stemness characteristics.

Receptor-interacting protein kinase 3 (RIPK3) can induce necroptosis, apoptosis, or cell proliferation and is silenced in several hematological malignancies. We previously reported that RIPK3 activity independent of its kinase domain induces caspase-mediated p65/RelA cleavage, resulting in N-terminal 1-361 and C-terminal 362-549 fragments. We show here that a noncleavable p65/RelA D361E mutant expressed in DA1-3b leukemia cells decreases mouse survival times and that coexpression of p65/RelA fragments increases the tumorigenicity of B16F1 melanoma cells. This aggressiveness in vivo did not correlate with NF-κB activity measured in vitro. The fragments and p65/RelA D361E mutant induced different expression profiles in DA1-3b and B16F1 cells. Stemness markers were affected: p65/RelA D361E increased ALDH activity in DA1-3b cells, and fragment expression increased melanoma sphere formation in B16/F1 cells. p65/RelA fragments and the D361E noncleavable mutant decreased oxidative or glycolytic cell metabolism, with differences observed between models. Thus, p65/RelA cleavage initiated by kinase-independent RIPK3 activity in cancer cells is not neutral and induces pleiotropic effects in vitro and in vivo that may vary across tumor types.

Metabolic rewiring in cancer cells overexpressing the glucocorticoid-induced leucine zipper protein (GILZ): Activation of mitochondrial oxidative phosphorylation and sensitization to oxidative cell death induced by mitochondrial targeted drugs.

Cancer cell metabolism is largely controlled by oncogenic signals and nutrient availability. Here, we highlighted that the glucocorticoid-induced leucine zipper (GILZ), an intracellular protein influencing many signaling pathways, reprograms cancer cell metabolism to promote proliferation. We provided evidence that GILZ overexpression induced a significant increase of mitochondrial oxidative phosphorylation as evidenced by the augmentation in basal respiration, ATP-linked respiration as well as respiratory capacity. Pharmacological inhibition of glucose, glutamine and fatty acid oxidation reduced the activation of GILZ-induced mitochondrial oxidative phosphorylation. At glycolysis level, GILZ-overexpressing cells enhanced the expression of glucose transporters in their plasmatic membrane and showed higher glycolytic reserve. 1H NMR metabolites quantification showed an up-regulation of amino acid biosynthesis. The GILZ-induced metabolic reprograming is present in various cancer cell lines regardless of their driver mutations status and is associated with higher proliferation rates persisting under metabolic stress conditions. Interestingly, high levels of OXPHOS made GILZ-overexpressing cells vulnerable to cell death induced by mitochondrial pro-oxidants. Altogether, these data indicate that GILZ reprograms cancer metabolism towards mitochondrial OXPHOS and sensitizes cancer cells to mitochondria-targeted drugs with pro-oxidant activities.

Melanoma dormancy in a mouse model is linked to GILZ/FOXO3A-dependent quiescence of disseminated stem-like cells.

Metastatic cancer relapses following the reactivation of dormant, disseminated tumour cells; however, the cells and factors involved in this reactivation are just beginning to be identified. Using an immunotherapy-based syngeneic model of melanoma dormancy and GFP-labelled dormant cell-derived cell lines, we determined that vaccination against melanoma prevented tumour growth but did not prevent tumour cell dissemination or eliminate all tumour cells. The persistent disseminated melanoma tumour cells were quiescent and asymptomatic for one year. The quiescence/activation of these cells in vitro and the dormancy of melanoma in vivo appeared to be regulated by glucocorticoid-induced leucine zipper (GILZ)-mediated immunosuppression. GILZ expression was low in dormant cell-derived cultures, and re-expression of GILZ inactivated FOXO3A and its downstream target, p21CIP1. The ability of dormancy-competent cells to re-enter the cell cycle increased after a second round of cellular dormancy in vivo in association with shortened tumour dormancy period and faster and more aggressive melanoma relapse. Our data indicate that future cancer treatments should be adjusted according to the stage of disease progression.

GILZ overexpression attenuates endoplasmic reticulum stress-mediated cell death via the activation of mitochondrial oxidative phosphorylation.

The Glucocorticoïd-induced leucine zipper (GILZ) protein has profound anti-inflammatory activities in haematopoietic cells. GILZ regulates numerous signal transduction pathways involved in proliferation and survival of normal and neoplastic cells. Here, we have demonstrated the potential of GILZ in alleviating apoptosis induced by ER stress inducers. Whereas the glucocorticoid, dexamethasone, protects from tunicamycin-induced cell death, silencing endogeneous GILZ in dexamethasone-treated cancer cells alter the capacity of glucocorticoids to protect from tunicamycin-mediated apoptosis. Under ER stress conditions, overexpression of GILZ significantly reduced activation of mitochondrial pathway of apoptosis by maintaining Bcl-xl level. GILZ protein affects the UPR signaling shifting the balance towards pro-survival signals as judged by down-regulation of CHOP, ATF4, XBP1s mRNA and increase in GRP78 protein level. Interestingly, GILZ sustains high mitochondrial OXPHOS during ER stress and cytoprotection mediated by GILZ is abolished in cells depleted of mitochondrial DNA, which are OXPHOS-deficient. These findings reveal a new role of GILZ, which acts as a cytoprotector against ER stress through a pathway involving mitochondrial OXPHOS.

The level of Ets-1 protein is regulated by poly(ADP-ribose) polymerase-1 (PARP-1) in cancer cells to prevent DNA damage.

Ets-1 is a transcription factor that regulates many genes involved in cancer progression and in tumour invasion. It is a poor prognostic marker for breast, lung, colorectal and ovary carcinomas. Here, we identified poly(ADP-ribose) polymerase-1 (PARP-1) as a novel interaction partner of Ets-1. We show that Ets-1 activates, by direct interaction, the catalytic activity of PARP-1 and is then poly(ADP-ribosyl)ated in a DNA-independent manner. The catalytic inhibition of PARP-1 enhanced Ets-1 transcriptional activity and caused its massive accumulation in cell nuclei. Ets-1 expression was correlated with an increase in DNA damage when PARP-1 was inhibited, leading to cancer cell death. Moreover, PARP-1 inhibitors caused only Ets-1-expressing cells to accumulate DNA damage. These results provide new insight into Ets-1 regulation in cancer cells and its link with DNA repair proteins. Furthermore, our findings suggest that PARP-1 inhibitors would be useful in a new therapeutic strategy that specifically targets Ets-1-expressing tumours.

Exploiting mitochondrial dysfunction for effective elimination of imatinib-resistant leukemic cells.

Challenges today concern chronic myeloid leukemia (CML) patients resistant to imatinib. There is growing evidence that imatinib-resistant leukemic cells present abnormal glucose metabolism but the impact on mitochondria has been neglected. Our work aimed to better understand and exploit the metabolic alterations of imatinib-resistant leukemic cells. Imatinib-resistant cells presented high glycolysis as compared to sensitive cells. Consistently, expression of key glycolytic enzymes, at least partly mediated by HIF-1α, was modified in imatinib-resistant cells suggesting that imatinib-resistant cells uncouple glycolytic flux from pyruvate oxidation. Interestingly, mitochondria of imatinib-resistant cells exhibited accumulation of TCA cycle intermediates, increased NADH and low oxygen consumption. These mitochondrial alterations due to the partial failure of ETC were further confirmed in leukemic cells isolated from some imatinib-resistant CML patients. As a consequence, mitochondria generated more ROS than those of imatinib-sensitive cells. This, in turn, resulted in increased death of imatinib-resistant leukemic cells following in vitro or in vivo treatment with the pro-oxidants, PEITC and Trisenox, in a syngeneic mouse tumor model. Conversely, inhibition of glycolysis caused derepression of respiration leading to lower cellular ROS. In conclusion, these findings indicate that imatinib-resistant leukemic cells have an unexpected mitochondrial dysfunction that could be exploited for selective therapeutic intervention.

Genomic characterization of Imatinib resistance in CD34+ cell populations from chronic myeloid leukaemia patients.

To ascertain genomic alterations associated with Imatinib resistance in chronic myeloid leukaemia, we performed high resolution genomic analysis of CD34(+) cells from 25 Imatinib (IM) resistant and 11 responders CML patients. Using patients' T-cells as reference, we found significant association between number of acquired cryptic copy number alterations (CNA) and disease phase (p=0.036) or loss of IM response for patients diagnosed in chronic phase (CP) (p=0.04). Recurrent cryptic losses were identified on chromosomes 7, 12 and 13. On chromosome 7, recurrent deletions of the IKZF1 locus were detected, for the first time, in 4 patients in CP.

Humulane and germacrane sesquiterpenes from Ferula lycia.

Five new juniferol esters (1-5), along with six known humulane derivatives (6-11), were isolated from the roots of Ferula lycia, an endemic Turkish species. The fruits of the same species were also investigated and led to the isolation of these same compounds, as well as two known germacrane esters (12 and 13). All isolated sesquiterpenes were assayed for cytotoxicity against two tyrosine kinase inhibitor-resistant cell lines, K562R and DA1-3b/M2(BCR-ABL). The two most active compounds, juniferinin (7) and 6-beta-p-hydroxybenzoyloxygermacra-1(10),4-diene (12), were moderately active against Raji lymphoma cells but also displayed some toxicity against healthy bone marrow cells.

Activity of ladanein on leukemia cell lines and its occurrence in Marrubium vulgare.

Three methoxylated flavones isolated from Marrubium peregrinum - ladanein, scutellarein-5,7,4'-trimethyl ether, and scutellarein-5,6,7,4'-tetramethyl ether - were assayed for their cytotoxicity towards a recently developed dasatinib-resistant murine leukemia cell line (DA1-3b/M2 (BCR-ABL)), together with the structurally related non-methylated flavone scutellarein. The most active compound, ladanein, was looked for in 20 common Lamiaceae species by a quick HPLC screening. Among the possible positive results, the most interesting source was found to be Marrubium vulgare, which led to the isolation and identification of ladanein for the first time in this species. Ladanein also displayed moderate (20-40 microM) activities against K562, K562R (imatinib-resistant), and 697 human leukemia cell lines but was toxic neither to MOLM13 nor to human peripheral blood mononuclear cells. This work provides a common natural source for the hemi-synthesis of future ladanein-derived flavones and the study of their antileukemic activity.

Activity of elaeochytrin A from Ferula elaeochytris on leukemia cell lines.

Phytochemical investigation of the roots of Ferula elaeochytris made it possible to isolate two sesquiterpene esters, 6-anthraniloyljaeschkeanadiol (elaeochytrin A) and 4beta-hydroxy-6alpha-(p-hydroxybenzoyloxy)dauc-9-ene (elaeochytrin B), as well as eight known compounds: 6-angeloyljaeschkeanadiol, teferidin, ferutinin, 6-(p-hydroxybenzoyl)epoxyjaeschkeanadiol, 6-(p-hydroxybenzoyl)lancerotriol, 5-caffeoylquinic acid, 1,5-dicaffeoylquinic acid and sandrosaponin IX. The cytotoxic activities of all compounds were investigated on K562R (imatinib-resistant) human chronic myeloid leukaemia and DA1-3b/M2(BCR-ABL) (dasatinib-resistant) mouse leukemia cell line. Elaeochytrin A was the most active compound on both cell lines (IC(50)=12.4 and 7.8microM, respectively). It was also tested on non-resistant human promyelocytic leukemia cells (HL60, IC(50)=13.1microM) and was not toxic to normal peripheral blood mononuclear cells up to 100microM.

Candida albicans phospholipomannan promotes survival of phagocytosed yeasts through modulation of bad phosphorylation and macrophage apoptosis.

The surface of the pathogenic yeast Candida albicans is coated with phospholipomannan (PLM), a phylogenetically unique glycolipid composed of beta-1,2-oligomannosides and phytoceramide. This study compared the specific contribution of PLM to the modulation of signaling pathways linked to the survival of C. albicans in macrophages in contrast to Saccharomyces cerevisiae. C. albicans endocytosis by J774 and disregulation of the ERK1/2 signal transduction pathway was associated downstream with a reduction in Bad Ser-112 phosphorylation and disappearance of free Bcl-2. This suggested an apoptotic effect, which was confirmed by staining of phosphatidylserine in the macrophage outer membrane. The addition of PLM to macrophages incubated with S. cerevisiae mimicked each of the disregulation steps observed with C. albicans and promoted the survival of S. cerevisiae. Externalization of membranous phosphatidylserine, loss of mitochondrial integrity, and DNA fragmentation induced by PLM showed that this molecule promoted yeast survival by inducing host cell death. These findings suggest strongly that PLM is a virulence attribute of C. albicans and that elucidation of the relationship between structure and apoptotic activity is an innovative field of research.

Role of phospholipomannan in Candida albicans escape from macrophages and induction of cell apoptosis through regulation of bad phosphorylation.

Candida albicans, the most common opportunistic fungal pathogen of humans is a part of the normal microbial flora. To investigate host-parasite interaction related to the commensal-pathogen switch of this yeast we compared the response of macrophages to C. albicans and to the non-pathogenic yeast Saccharomyces cerevisiae. In contrast to S. cerevisiae, C. albicans survived within macrophages. This escape from macrophages was associated with qualitative differences in the sequential phosphorylation of MEK, ERK1/2, and p90RSK during phagocytosis. Decreased activation of this pathway was observed with C. albicans and was associated with a species-specific overexpression of the MEK phosphatase, MKP-1. Dysregulation of the ERK1/2/p90RSK signal transduction pathway by C. albicans was associated downstream with reduction in Bad phosphorylation, specifically at Ser-112, and disappearance of free Bcl-2. This ended at apoptosis of cells that have ingested C. albicans, as revealed by staining of phosphatidylserine exposure in the macrophage outer membrane. The role of phospholipomannan (PLM), a phylogenetically unique glycolipid with a phytoceramide moiety expressed at the surface of and shed by C. albicans, was examined. Addition of PLM to macrophages led to dysregulation similar to that observed with live C. albicans and promoted the survival of the sensitive S. cerevisiae within the cells. Evidence of externalization of membranous phosphatidylserine, loss of mitochondrial integrity, and DNA fragmentation after incubation of macrophages with PLM suggest that this molecule supported the activities observed with C. albicans yeast cells.