A Network of 17 Microtubule-Related Genes Highlights Functional Deregulations in Breast Cancer.

A wide panel of microtubule-associated proteins and kinases is involved in coordinated regulation of the microtubule cytoskeleton and may thus represent valuable molecular markers contributing to major cellular pathways deregulated in cancer. We previously identified a panel of 17 microtubule-related (MT-Rel) genes that are differentially expressed in breast tumors showing resistance to taxane-based chemotherapy. In the present study, we evaluated the expression, prognostic value and functional impact of these genes in breast cancer. We show that 14 MT-Rel genes (KIF4A, ASPM, KIF20A, KIF14, TPX2, KIF18B, KIFC1, AURKB, KIF2C, GTSE1, KIF15, KIF11, RACGAP1, STMN1) are up-regulated in breast tumors compared with adjacent normal tissue. Six of them (KIF4A, ASPM, KIF20A, KIF14, TPX2, KIF18B) are overexpressed by more than 10-fold in tumor samples and four of them (KIF11, AURKB, TPX2 and KIFC1) are essential for cell survival. Overexpression of all 14 genes, and underexpression of 3 other MT-Rel genes (MAST4, MAPT and MTUS1) are associated with poor breast cancer patient survival. A Systems Biology approach highlighted three major functional networks connecting the 17 MT-Rel genes and their partners, which are centered on spindle assembly, chromosome segregation and cytokinesis. Our studies identified mitotic Aurora kinases and their substrates as major targets for therapeutic approaches against breast cancer.

[Mitochondrial transport: How does it impact cancer?] / Le transport mitochondrial - Quel impact dans le cancer ?

Cancer cells are characterized by a deregulation of their metabolic activity, which allows them to meet a high energy demand. Mitochondria are key organelles that control several metabolic processes and represent the main source of energy in the form of ATP. Intracellular transport of mitochondria is essential for addressing these organelles to the right place at the right time according to energy requirement. Mitochondrial transport in cancer cells involves mitochondria-associated Miro/TRAK complexes that bind to motor proteins (kinesins, dyneins and myosins) to promote mitochondrial displacement along microtubules or actin filaments. This review focuses on the molecular players of intracellular mitochondrial transport along microtubules during cell migration and mitosis, and their deregulation in tissues from cancer patients. Intercellular mitochondrial transport upon cancer cell exposure to hypoxia or chemotherapy is also presented. This field of investigation opens new interesting perspectives in oncology, as targeting mitochondrial transport may represent an innovative strategy for treating cancer.

Title: Le transport mitochondrial - Quel impact dans le cancer ? Abstract: La reprogrammation métabolique est l'un des marqueurs de la carcinogenèse. Au cœur de cette reprogrammation se trouvent les mitochondries qui produisent l'énergie sous forme de molécules d'ATP. La régulation spatio-temporelle de la production d'ATP, indispensable pour fournir l'énergie au bon endroit et au bon moment, est assurée par le transport intracellulaire des mitochondries. Les complexes Miro/TRAK présents à la surface des mitochondries se lient aux protéines motrices de la cellule (dynéine, kinésine, myosine) pour transporter les mitochondries le long du cytosquelette. Ces acteurs du transport mitochondrial sont souvent dérégulés dans le cancer. Nous présentons dans cette revue les mécanismes par lesquels le transport mitochondrial contribue à la migration, à la division cellulaire et à la réponse au stress des cellules cancéreuses. Décrypter ces mécanismes pourrait ouvrir la voie à de nouvelles approches thérapeutiques en oncologie.

Mitochondrial Metabolism in Carcinogenesis and Cancer Therapy.

Carcinogenesis is a multi-step process that refers to transformation of a normal cell into a tumoral neoplastic cell. The mechanisms that promote tumor initiation, promotion and progression are varied, complex and remain to be understood. Studies have highlighted the involvement of oncogenic mutations, genomic instability and epigenetic alterations as well as metabolic reprogramming, in different processes of oncogenesis. However, the underlying mechanisms still have to be clarified. Mitochondria are central organelles at the crossroad of various energetic metabolisms. In addition to their pivotal roles in bioenergetic metabolism, they control redox homeostasis, biosynthesis of macromolecules and apoptotic signals, all of which are linked to carcinogenesis. In the present review, we discuss how mitochondria contribute to the initiation of carcinogenesis through gene mutations and production of oncometabolites, and how they promote tumor progression through the control of metabolic reprogramming and mitochondrial dynamics. Finally, we present mitochondrial metabolism as a promising target for the development of novel therapeutic strategies.

Preimplantation factor modulates trophoblastic invasion throughout the decidualization of human endometrial stromal cells.

BACKGROUND: Successful human embryo implantation requires the differentiation of endometrial stromal cells (ESCs) into decidual cells during a process called decidualization. ESCs express specific markers of decidualization, including prolactin, insulin-like growth factor-binding protein-1 (IGFBP-1), and connexin-43. Decidual cells also control of trophoblast invasion by secreting various factors, such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases. Preimplantation factor (PIF) is a recently identified, embryo-derived peptide with activities at the fetal-maternal interface. It creates a favorable pro-inflammatory environment in human endometrium and directly controls placental development by increasing the human trophoblastic cells' ability to invade the endometrium. We hypothesized that PIF's effects on the endometrium counteract its pro-invasive effects. METHODS: We tested sPIF effect on the expression of three decidualization markers by RT-qPCR and/or immunochemiluminescence assay. We examined sPIF effect on human ESC migration by performing an in vitro wound healing assay. We analyzed sPIF effect on endometrial control of human trophoblast invasion by performing a zymography and an invasion assay. RESULTS: Firstly, we found that a synthetic analog of PIF (sPIF) significantly upregulates the mRNA expression of IGFBP-1 and connexin-43, and prolactin secretion in ESCs - suggesting a pro-differentiation effect. Secondly, we showed that the HTR-8/SVneo trophoblastic cell line's invasive ability was low in the presence of conditioned media from ESCs cultured with sPIF. Thirdly, this PIF's anti-invasive action was associated with a specifically decrease in MMP-9 activity. CONCLUSION: Taken as a whole, our results suggest that PIF accentuates the decidualization process and the production of endometrial factors that limit trophoblast invasion. By controlling both trophoblast and endometrial cells, PIF therefore appears to be a pivotal player in the human embryo implantation process.

Predicting and Overcoming Taxane Chemoresistance.

Taxanes are microtubule-targeting drugs used as cytotoxic chemotherapy to treat most solid tumors. The development of resistance to taxanes is a major cause of therapeutic failure and overcoming chemoresistance remains an important challenge to improve patient's outcome. Extensive efforts have been made recently to identify predictive biomarkers to select populations of patients who will benefit from taxane-based chemotherapy and avoid inefficient treatment of patients with innate resistance. This, together with the discovery of new mechanisms of resistance that include metabolic reprogramming and dialogue between tumor and its microenvironment, pave the way to a new era of personalized medicine. In this review, we recapitulate recent insights into taxane resistance and present promising emerging strategies to overcome chemoresistance in the future.

Improving breast cancer sensitivity to paclitaxel by increasing aneuploidy.

Predictive biomarkers for tumor response to neoadjuvant chemotherapy are needed in breast cancer. This study investigates the predictive value of 280 genes encoding proteins that regulate microtubule assembly and function. By analyzing 3 independent multicenter randomized cohorts of breast cancer patients, we identified 17 genes that are differentially regulated in tumors achieving pathological complete response (pCR) to neoadjuvant chemotherapy. We focused on the MTUS1 gene, whose major product, ATIP3, is a microtubule-associated protein down-regulated in aggressive breast tumors. We show here that low levels of ATIP3 are associated with an increased pCR rate, pointing to ATIP3 as a predictive biomarker of breast tumor chemosensitivity. Using preclinical models of patient-derived xenografts and 3-dimensional models of breast cancer cell lines, we show that low ATIP3 levels sensitize tumors to the effects of taxanes but not DNA-damaging agents. ATIP3 silencing improves the proapoptotic effects of paclitaxel and induces mitotic abnormalities, including centrosome amplification and multipolar spindle formation, which results in chromosome missegregation leading to aneuploidy. As shown by time-lapse video microscopy, ATIP3 depletion exacerbates cytokinesis failure and mitotic death induced by low doses of paclitaxel. Our results favor a mechanism by which the combination of ATIP3 deficiency and paclitaxel treatment induces excessive aneuploidy, which in turn results in elevated cell death. Together, these studies highlight ATIP3 as an important regulator of mitotic integrity and a useful predictive biomarker for a population of chemoresistant breast cancer patients.

Adiponectin limits differentiation and trophoblast invasion in human endometrial cells.

Successful human embryo implantation requires a proper differentiation of endometrial stromal cells (ESCs) into decidual cells, during a process called decidualization. ESCs express specific molecules, such as prolactin, insulin-like growth factor-binding protein-1 (IGFBP-1) and connexin-43. Decidual cells are also involved in the control of trophoblast invasion, by secreting various factors, such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Adiponectin is an adipokine with insulin-sensitizing, anti-inflammatory and anti-proliferative effects. At the embryo-maternal interface, adiponectin promotes differentiation and invasion of human trophoblastic cells. We hypothesize that the effects of adiponectin on endometrium could counteract its pro-invasive effects previously described in the human trophoblast. In this context, we have firstly demonstrated that adiponectin downregulates IGFBP-1 and connexin-43 mRNA expressions, as well as prolactin secretion in ESCs, suggesting an anti-differentiative effect of adiponectin. Secondly, we found that invasive capacities of trophoblastic cell line HTR-8/SVneo are reduced in the presence of conditioned media from ESC cultured in the presence of adiponectin. Adiponectin's anti-invasive action is associated with a decreased activity of MMP-2 and MMP-9, and an increased TIMP-3 mRNA expression in ESCs. Finally, adiponectin receptors (ADIPOR1 and ADIPOR2) knockdown abolishes the anti-differentiative and anti-invasive effects of adiponectin in human ESCs. Altogether, our results suggest that adiponectin reduces the decidualization process and inversely induces the production of endometrial factors that limit trophoblast invasion. Thus, through a dual control in trophoblast and endometrial cells, adiponectin appears as a pivotal actor of the embryo implantation process.

Preimplantation factor is an anti-apoptotic effector in human trophoblasts involving p53 signaling pathway.

From the earliest stages of gestation, embryonic-maternal interaction has a key role in a successful pregnancy. Various factors present during gestation may significantly influence this type of juxta/paracrine interaction. PreImplantation Factor (PIF) is a recently identified factor with activity at the fetomaternal interface. PIF is secreted by viable embryos and directly controls placental development by increasing the invasive capacity of human extravillous trophoblasts (EVTs). To further specify PIF's role in the human placenta, we analyzed the genome-wide expression profile of the EVT in the presence of a synthetic PIF analog (sPIF). We found that sPIF exposure altered several pathways related to p53 signaling, survival and the immune response. Functional assays revealed that sPIF acts through the p53 pathway to reduce both early and late trophoblast apoptosis. More precisely, sPIF (i) decreases the phosphorylation of p53 at Ser-15, (ii) enhances the B-cell lymphoma-2 (BCL2) expression and (iii) reduces the BCL2-associated X protein (BAX) and BCL2 homologous antagonist killer (BAK) mRNA expression levels. Furthermore, invalidation experiments of TP53 allowed us to demonstrate that PIF's effects on placental apoptosis seemed to be essentially mediated by this gene. We have clearly shown that p53 and sPIF pathways could interact in human trophoblast and thus promotes cell survival. Furthermore, sPIF was found to regulate a gene network related to immune tolerance in the EVT, which emphasizes the beneficial effect of this peptide on the human placenta. Finally, the PIF protein levels in placentas from pregnancies affected by preeclampsia or intra-uterine growth restriction were significantly lower than in gestational age-matched control placentas. Taken as a whole, our results suggest that sPIF protects the EVT's functional status through a variety of mechanisms. Clinical application of sPIF in the treatment of disorders of early pregnancy can be envisioned.

Involvement of estrogen-related receptor-γ and mitochondrial content in intrauterine growth restriction and preeclampsia.

OBJECTIVE: To measure mitochondrial content and the expression of estrogen-related receptor-γ (ERRγ, a major inducer of mitochondrial biogenesis) in placentas from women with intrauterine growth restriction (IUGR) associated or not with pre-eclampsia (PE), relative to control placentas. DESIGN: Case-control study. SETTING: Teaching hospital and university research laboratory. PATIENT(S): Thirty-nine placentas from women with IUGR, 8 IUGR+PE, and 30 controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Mitochondrial DNA and protein content, gene and protein expression. RESULT(S): We observed significantly lower placental mitochondrial DNA and protein contents (associated with down-regulation of ERRγ expression) in IUGR and IUGR+PE placentas, relative to control placentas. Our results also revealed that the placental mitochondrial DNA content was directly correlated with fetal weight. Moreover, we observed significantly lower peroxisome proliferator-activated receptor-γ coactivator-1α and sirtuin 1 messenger RNA expression levels in IUGR+PE placentas, relative to control placentas. CONCLUSION(S): The low mitochondrial DNA and protein contents observed in IUGR placentas are probably due to down-regulation of ERRγ expression. This finding suggests that ERRγ has a major role in the control of placental development.

Preimplantation factor (PIF) promotes human trophoblast invasion.

Preimplantation factor (PIF) is a peptide secreted by viable mammalian embryos. Moreover, it can be detected in the circulation of pregnant women. Recently, it was shown that PIF promotes invasion in trophoblast cell lines in vitro. Successful human embryo implantation depends on a deep and highly controlled invasion of extravillous trophoblast (EVT) in the maternal endometrium. Trophoblast invasion is regulated in part by matrix metalloproteinase (MMP) activity and integrin expression. The present study demonstrates the presence of PIF in early pregnancy and characterizes its effects on primary human trophoblast invasion. At the fetomaternal interface, intense PIF labeling by immunohistochemistry was present during early gestation in villous trophoblasts and EVTs. A decrease of labeling was observed at term. Furthermore, PIF significantly promoted invasion of human EVT isolated from first-trimester placenta. The proinvasive regulatory effect of PIF in EVT was associated with 1) increased MMP9 activity and 2) reduced tissue inhibitor of metalloproteinase-1 (TIMP1) mRNA expression. PIF also regulated alpha v and alpha 1 integrin mRNA expressions. Last, the proinvasive effect of PIF appeared to be mediated by the mitogen-activated protein kinase (MAPK), phosphoinositide-3-kinase (PI3K), and Janus-kinase signal transducer and activator of transcription (JAK-STAT) signaling pathways. In summary, this work describes the direct, positive effect of PIF on the control of human trophoblastic cell invasion by modulation of MMP/TIMP balance and integrin expression. Moreover, these results suggest that PIF is involved in pathological pregnancies characterized by insufficient or excessive trophoblast invasion.

Anti-Müllerian hormone recruits BMPR-IA in immature granulosa cells.

Anti-Müllerian hormone (AMH) is a member of the TGF-ß superfamily secreted by the gonads of both sexes. This hormone is primarily known for its role in the regression of the Müllerian ducts in male fetuses. In females, AMH is expressed in granulosa cells of developing follicles. Like other members of the TGF-ß superfamily, AMH transduces its signal through two transmembrane serine/threonine kinase receptors including a well characterized type II receptor, AMHR-II. The complete signalling pathway of AMH involving Smads proteins and the type I receptor is well known in the Müllerian duct and in Sertoli and Leydig cells but not in granulosa cells. In addition, few AMH target genes have been identified in these cells. Finally, while several co-receptors have been reported for members of the TGF-ß superfamily, none have been described for AMH. Here, we have shown that none of the Bone Morphogenetic Proteins (BMPs) co-receptors, Repulsive guidance molecules (RGMs), were essential for AMH signalling. We also demonstrated that the main Smad proteins used by AMH in granulosa cells were Smad 1 and Smad 5. Like for the other AMH target cells, the most important type I receptor for AMH in these cells was BMPR-IA. Finally, we have identified a new AMH target gene, Id3, which could be involved in the effects of AMH on the differentiation of granulosa cells and its other target cells.