Identification of glucocorticoid-induced leucine zipper as a key regulator of tumor cell proliferation in epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Little is known about the molecules that contribute to tumor progression of epithelial ovarian cancer (EOC), currently a leading cause of mortality from gynecological malignancies. Glucocorticoid-Induced Leucine Zipper (GILZ), an intracellular protein widely expressed in immune tissues, has been reported in epithelial tissues and controls some of key signaling pathways involved in tumorigenesis. However, there has been no report on GILZ in EOC up to now. The objectives of the current study were to examine the expression of GILZ in EOC and its effect on tumor cell proliferation.</p> <p>Results</p> <p>GILZ expression was measured by immunohistochemical staining in tissue sections from 3 normal ovaries, 7 benign EOC and 50 invasive EOC. GILZ was not detected on the surface epithelium of normal ovaries and benign tumors. In contrast, it was expressed in the cytoplasm of tumor cells in 80% EOC specimens. GILZ immunostaining scores correlated positively to the proliferation marker Ki-67 (Spearman test in univariate analysis, <it>P </it>< 0.00001, r = 0.56). They were also higher in tumor cells containing large amounts of phosphorylated protein kinase B (p-AKT) (unpaired t test, <it>P </it>< 0.0001). To assess the effect of GILZ on proliferation and AKT activation, we used the BG-1 cell line derived from ovarian tumor cells as a cellular model. GILZ expression was either enhanced by stable transfection or decreased by the use of small interfering (si) RNA targeting GILZ. We found that GILZ increased cell proliferation, phospho-AKT cellular content and AKT kinase activity. Further, GILZ upregulated cyclin D1 and phosphorylated retinoblastoma (p-Rb), downregulated cyclin-dependent kinase inhibitor p21, and promoted the entry into S phase of cell cycle.</p> <p>Conclusion</p> <p>The present study is the first to identify GILZ as a molecule produced by ovarian cancer cells that promotes cell cycle progression and proliferation. Our findings clearly indicate that GILZ activates AKT, a crucial signaling molecule in tumorigenesis. GILZ thus appears as a potential key molecule in EOC.</p

CXCL12 expression by healthy and malignant ovarian epithelial cells

<p>Abstract</p> <p>Background</p> <p>CXCL12 has been widely reported to play a biologically relevant role in tumor growth and spread. In epithelial ovarian cancer (EOC), CXCL12 enhances tumor angiogenesis and contributes to the immunosuppressive network. However, its prognostic significance remains unclear. We thus compared CXCL12 status in healthy and malignant ovaries, to assess its prognostic value.</p> <p>Methods</p> <p>Immunohistochemistry was used to analyze CXCL12 expression in the reproductive tracts, including the ovaries and fallopian tubes, of healthy women, in benign and borderline epithelial tumors, and in a series of 183 tumor specimens from patients with advanced primary EOC enrolled in a multicenter prospective clinical trial of paclitaxel/carboplatin/gemcitabine-based chemotherapy (GINECO study). Univariate COX model analysis was performed to assess the prognostic value of clinical and biological variables. Kaplan-Meier methods were used to generate progression-free and overall survival curves.</p> <p>Results</p> <p>Epithelial cells from the surface of the ovary and the fallopian tubes stained positive for CXCL12, whereas the follicles within the ovary did not. Epithelial cells in benign, borderline and malignant tumors also expressed CXCL12. In EOC specimens, CXCL12 immunoreactivity was observed mostly in epithelial tumor cells. The intensity of the signal obtained ranged from strong in 86 cases (47%) to absent in 18 cases (<10%). This uneven distribution of CXCL12 did not reflect the morphological heterogeneity of EOC. CXCL12 expression levels were not correlated with any of the clinical parameters currently used to determine EOC prognosis or with HER2 status. They also had no impact on progression-free or overall survival.</p> <p>Conclusion</p> <p>Our findings highlight the previously unappreciated constitutive expression of CXCL12 on healthy epithelia of the ovary surface and fallopian tubes, indicating that EOC may originate from either of these epithelia. We reveal that CXCL12 production by malignant epithelial cells precedes tumorigenesis and we confirm in a large cohort of patients with advanced EOC that CXCL12 expression level in EOC is not a valuable prognostic factor in itself.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00052468">NCT00052468</a></p

Rôle du Glucocorticoid-induced Leucine Zipper (GILZ) dans le cancer épithélial de l'ovaire

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

Etude de deux chimiokines cxcl12/sdf-1 et fractalkine (fkn)/cx3cl1 dans le cancer epithelial des ovaires

Le cancer épithélial de l ovaire (CEO) est une cause majeure de mortalité parcancer gynécologique. Il est associé à un mauvais pronostic car il est souventdécouvert à un stade tardif. Mieux comprendre les causes et les mécanismesmoléculaires et cellulaires associés à la progression de ce cancer représente unenjeu majeur.Les deux chimiokines CXCL12/SDF-1 et fractalkine (FKN)/CX3CL1 ont étéimpliquées dans diverses tumeurs. La chimiokine SDF-1, a un effetimmunosuppresseur dans le CEO. Elle est aussi impliquée dans l angiogenèsetumorale. L effet de SDF-1 médié par CXCR4 est également impliqué dans larégulation de la prolifération, la survie, la migration et l'invasion des cellulescancéreuses. La FKN, a largement été mise en évidence dans les tissusépithéliaux et dans divers cancers où elle peut avoir soit un rôle anti-tumoral soitun rôle pro-tumoral. Jusqu à présent la FKN n a pas été étudié dans le CEO.Dans notre étude, nous avons démontré l expression de SDF-1 et de la FKNdans l épithélium de surface de l ovaire sain et dans les tumeurs bénignes etmalignes. Ces résultats montrent que l expression de SDF-1 et de la FKNpréexiste à la tumorigenèse. Nous avons démontré une expression hétérogènedes deux chimiokines dans les cellules du CEO. Les niveaux d expression deSDF-1 dans les cellules tumorales sur une cohorte de 183 patientes n ont aucunevaleur pronostique sur la survie globale et sur la survie sans progressiontumorale des patientes atteintes par le CEO. L étude de la corrélation del expression de la FKN avec les deux marqueurs de prolifération, Ki-67 etGILZ, sur une autre cohorte de 54 patientes, complétée par des expériences invitro, a montré que GILZ augmente l expression de la FKN et d autre part que laFKN elle-même augmente la prolifération. Cette étude contribue à élucider lerôle de SDF-1 et de la FKN dans le CEO.Little is known about the molecules that contribute to tumor growth ofepithelial ovarian carcinomas (EOC) that remains the most lethal gynecologicalneoplasm in women.The two chemokines CXCL12/SDF-1 and fractalkine (FKN)/CX3CL1 havebeen widely studied in tumorigenesis. In epithelial ovarian cancer (EOC), SDF-1enhances tumor angiogenesis and contributes to the immunosuppressivenetwork. SDF-1 also acts on tumor cell proliferation and survival and, throughits main receptor CXCR4, governs the migration of malignant cells and theirinvasion of the peritoneum. The chemokine FKN has been documented inepithelial tissues and in various cancers. FKN have paradoxical effects intumors: anti-tumoral effect in some tumor entities and pro-tumoral effect inother tumor entities.In our study, we demonstrated the expression of SDF-1 and FKN on thesurface epithelium of normal ovaries and benign and malignant tumors,suggesting that the expression of these chemokines preexists to tumorigenesis.We also demonstrated an heterogeneous expression of both chemokines in EOC.In our large and homogeneous cohort (183 specimens of EOC), SDF-1expression levels had no effect on overall survival or progression-free survival.Thus, SDF-1 expression by tumor epithelial cells is not in itself a valuableprognostic factor in patients with advanced EOC. FKN immunostaining scores(in 54 specimens of EOC) correlated positively with the two proliferationmarkers: Ki-67 and GILZ. In vitro, we demonstrated that GILZ increases theexpression of FKN and that FKN itself increased proliferation. This studycontributes in elucidating the role of the two chemokines SDF-1 and FKN inEOC.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Effets de la progestérone sur la migration des matocytes HMC-1(560) en réponse à la chimiokine CXCL12 et sur leur prolifération spontanée

Les mastocytes sont des cellules du système immunitaire impliquées dans les réactions inflammatoires. Ils sont associés à différentes pathologies caractérisées par une augmentation locale de leur nombre. Les hormones ovariennes jouent un rôle sur les fonctions et le recrutement des mastocytes. La chimiokine SDF-1/CXCL12 est un facteur clé du recrutement des cellules du système immunitaire. Sur la lignée HMC-1560 de mastocytes humains, nous avons montré que la progestérone (1nM-1 M) diminue la migration des HMC-1560 en réponse à CXCL12 parallèlement à une diminution des signaux induit par CXCL12 et à la diminution de l expression de CXCR4, récepteur de CXCL12. La progestérone réduit aussi la prolifération spontanée des HMC-1560 consécutivement à un blocage des cellules en phase G0/G1 du cycle cellulaire. Enfin, nous avons mis en évidence une augmentation par la progestérone de l expression de Csk Homologous Kinase (CHK).The presence of mast cells in tissues implicated in many physiological functions and their accumulation is associated with several diseases. Mast cells recruitment in tissues depends on microenvironmental factors and hormones. On HMC-1560 human mast cells, progesterone significantly reduced cell migration towards CXCL12, a chemokine. Cells incubated with progesterone showed no rearrangment of actin filaments following the addition of CXCL12. The hormone also reduced the calcium response to CXCL12 and Akt phosphorylation. The amount of CXCR4 (mRNA, total protein) and the amount of membrane-bound protein were about reduced by progesterone. The spontaneous proliferation of HMC-1560 mast cells was also diminished up to 50%, with arrest in G1. This inhibition was accompanied by down regulation of phosphorylated Raf-1 and p42/44 MAPKs, and in parallel Csk Homolgous Kinase (CHK), an inhibitor for the Src-family members, was increased.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Identification of the chemokine CX3CL1 as a new regulator of malignant cell proliferation in epithelial ovarian cancer.

BACKGROUND:Little is known about the molecules that contribute to the growth of epithelial ovarian carcinomas (EOC), which remain the most lethal gynecological cancer in women. The chemokine Fractalkine/CX(3)CL1 has been widely reported to play a biologically relevant role in tumor growth and spread. We report here the first investigation of the expression and role of CX(3)CL1 in EOC. RESULTS:Epithelial cells from the surface of the ovary and the Fallopian tubes and from benign, borderline and malignant tumors all stained positive for CX(3)CL1. In tumor specimens from 54 women who underwent surgical treatment for EOC diagnosis, CX(3)CL1 immunoreactivity was unevenly distributed in epithelial tumor cells, and ranged from strong (33%) to absent (17%). This uneven distribution of CX(3)CL1 did not reflect the morphological heterogeneity of EOC. It was positively correlated with the proliferation index Ki-67 and with GILZ (glucocorticoid-induced leucine zipper), previously identified as an activator of the proliferation of malignant EOC cells. Hierarchical clustering analysis, including age at diagnosis, tumor grade, FIGO stage, Ki-67 index, CX(3)CL1, SDF-1/CXCL12 and GILZ immunostaining scores, distinguished two major clusters corresponding to low and high levels of proliferation and differing in terms of GILZ and CX(3)CL1 expression. GILZ overexpression in the carcinoma-derived BG1 cell line resulted in parallel changes in CX(3)CL1 products. Conversely, CX(3)CL1 promoted through its binding to CX(3)CR1 AKT activation and proliferation in BG1 cells. In a mouse subcutaneous xenograft model, the overexpression of GILZ was associated with higher expression of CX(3)CL1 and faster tumor growth. CONCLUSION:Our findings highlight the previously unappreciated constitutive expression of CX(3)CL1 preceding tumorigenesis in ovarian epithelial cells. Together with GILZ, this chemokine emerges as a regulator of cell proliferation, which may be of potential clinical relevance for the selection of the most appropriate treatment for EOC patients