NGF/TRKA Promotes ADAM17-Dependent Cleavage of P75 in Ovarian Cells: Elucidating a Pro-Tumoral Mechanism.

Nerve growth factor (NGF) and its high-affinity receptor TRKA are overexpressed in epithelial ovarian cancer (EOC) displaying a crucial role in the disease progression. Otherwise, NGF interacts with its low-affinity receptor P75, activating pro-apoptotic pathways. In neurons, P75 could be cleaved by metalloproteinases (α and γ-secretases), leading to a decrease in P75 signaling. Therefore, this study aimed to evaluate whether the shedding of P75 occurs in EOC cells and whether NGF/TRKA could promote the cleavage of the P75 receptor. The immunodetection of the α-secretase, ADAM17, TRKA, P75, and P75 fragments was assessed by immunohisto/cytochemistry and Western blot in biopsies and ovarian cell lines. The TRKA and secretases' inhibition was performed using specific inhibitors. The results show that P75 immunodetection decreased during EOC progression and was negatively correlated with the presence of TRKA in EOC biopsies. NGF/TRKA increases ADAM17 levels and the fragments of P75 in ovarian cells. This effect is abolished when cells are previously treated with ADAM17, γ-secretase, and TRKA inhibitors. These results indicate that NGF/TRKA promotes the shedding of P75, involving the activation of secretases such as ADAM17. Since ADAM17 has been proposed as a screening marker for early detection of EOC, our results contribute to understanding better the role of ADAM17 and NGF/TRKA in EOC pathogenesis, which includes the NGF/TRKA-mediated cleavage of P75.

Metformin Reduces NGF-Induced Tumour Promoter Effects in Epithelial Ovarian Cancer Cells.

Epithelial ovarian cancer (EOC) is a lethal gynaecological neoplasm characterized by rapid growth and angiogenesis. Nerve growth factor (NGF) and its high affinity receptor tropomyosin receptor kinase A (TRKA) contribute to EOC progression by increasing the expression of c-MYC, survivin and vascular endothelial growth factor (VEGF) along with a decrease in microRNAs (miR) 23b and 145. We previously reported that metformin prevents NGF-induced proliferation and angiogenic potential of EOC cells. In this study, we sought to obtain a better understanding of the mechanism(s) by which metformin blocks these NGF-induced effects in EOC cells. Human ovarian surface epithelial (HOSE) and EOC (A2780/SKOV3) cells were stimulated with NGF and/or metformin to assess the expression of c-MYC, ß-catenin, survivin and VEGF and the abundance of the tumor suppressor miRs 23b and 145. Metformin decreased the NGF-induced transcriptional activity of MYC and ß-catenin/T-cell factor/lymphoid enhancer-binding factor (TCF-Lef), as well as the expression of c-MYC, survivin and VEGF in EOC cells, while it increased miR-23b and miR-145 levels. The preliminary analysis of ovarian biopsies from women users or non-users of metformin was consistent with these in vitro results. Our observations shed light on the mechanisms by which metformin may suppress tumour growth in EOC and suggest that metformin should be considered as a possible complementary therapy in EOC treatment.

Follicle-stimulating hormone promotes nerve growth factor and vascular endothelial growth factor expression in epithelial ovarian cells.

Ovarian cancer is the first cause of death for gynecological malignances in developed countries and around 80% correspond to Epithelial Ovarian Cancer (EOC). Overexpression of Nerve Growth Factor (NGF) and its high affinity receptor TRKA are involved in EOC progression, modulating several oncogenic processes such as angiogenesis by the increase of Vascular Endothelial Growth Factor (VEGF). FSH receptors (FSH-R) are present in EOC, but their changes and contribution during EOC progression are still not thoroughly known. The aims of this study were to evaluate the abundance of FSH receptors during EOC differentiation and to determine whether FSH modulates oncoproteins such as NGF and VEGF in ovarian cells. FSH-R expression in EOC tissues and cell lines (A2780, poorly differentiated EOC cells and HOSE, non-tumoral ovarian surface epithelial cells) were measured by RT-PCR and laser capture of epithelial cells from EOC samples by qPCR. FSH-R protein levels were evaluated by immunohisto/cytochemistry. Additionally, ovarian explants and ovarian cell lines were stimulated with FSH and/or FSH-R inhibitor to assess NGF and VEGF mRNA and protein levels. The results showed that FSH-R levels decreased during EOC progression, nevertheless these receptors are still present in poorly differentiated EOC. FSH increased NGF expression in ovarian cells, which was prevented using a FSH-R inhibitor. Similarly, in ovarian cancer explants, FSH increased NGF and VEGF mRNA, as well as NGF protein levels. These results suggest that FSH would display a key role not only in initial stages of EOC, but also in late stages of this disease, by modulation of NGF and VEGF levels in EOC cells.

NGF-Enhanced Vasculogenic Properties of Epithelial Ovarian Cancer Cells Is Reduced by Inhibition of the COX-2/PGE2 Signaling Axis.

Epithelial ovarian cancer (EOC) is a lethal gynecological neoplasia characterized by extensive angiogenesis and overexpression of nerve growth factor (NGF). Here, we investigated the mechanism by which NGF increases vascular endothelial growth factor (VEGF) expression and the vasculogenic potential of EOC cells, as well as the contribution of the cyclooxygenase 2/prostaglandin E2 (COX-2/PGE2) signaling axis to these events. EOC biopsies and ovarian cell lines were used to determine COX-2 and PGE2 levels, as well as those of the potentially pro-angiogenic proteins c-MYC (a member of the Myc transcription factors family), survivin, and ß-catenin. We observed that COX-2 and survivin protein levels increased during EOC progression. In the EOC cell lines, NGF increased the COX-2 and PGE2 levels. In addition, NGF increased survivin, c-MYC, and VEGF protein levels, as well as the transcriptional activity of c-MYC and ß-catenin/T-cell factor/lymphoid enhancer-binding factor (TCF-Lef) in a Tropomyosin receptor kinase A (TRKA)-dependent manner. Also, COX-2 inhibition prevented the NGF-induced increases in these proteins and reduced the angiogenic score of endothelial cells stimulated with conditioned media from EOC cells. In summary, we show here that the pro-angiogenic effect of NGF in EOC depends on the COX-2/PGE2 signaling axis. Thus, inhibition COX-2/PGE2 signaling will likely be beneficial in the treatment of EOC.

Paraneoplastic cerebellar degeneration in a patient with a primary fallopian tube adenocarcinoma. A case report and brief review.

We describe a 65-year-old woman with subacute cerebellar syndrome expressed as severe ataxia, and the presence of anti Purkinje cell antibodies (Anti-Yo). A small adnexal mass was only evident on PET CT with the pathological feature of fallopian tube adenocarcinoma. Anti-Yo antibodies have been strongly associated with paraneoplastic cerebellar degeneration, and nearly always associated to ovarian adenocarcinomas. Few cases have been reported in which this paraneoplastic syndrome has been related to fallopian tube adenocarcinoma. In this report, we discuss this association and its relation with fallopian tube and ovarian carcinoma.

The nerve growth factor alters calreticulin translocation from the endoplasmic reticulum to the cell surface and its signaling pathway in epithelial ovarian cancer cells.

Ovarian cancer is the seventh most common cancer among women worldwide, causing approximately 120,000 deaths every year. Immunotherapy, designed to boost the body's natural defenses against cancer, appears to be a promising option against ovarian cancer. Calreticulin (CRT) is an endoplasmic reticulum (ER) resident chaperone that, translocated to the cell membrane after ER stress, allows cancer cells to be recognized by the immune system. The nerve growth factor (NGF) is a pro-angiogenic molecule overexpressed in this cancer. In the present study, we aimed to determine weather NGF has an effect in CRT translocation induced by cytotoxic and ER stress. We treated A2780 ovarian cancer cells with NGF, thapsigargin (Tg), an ER stress inducer and mitoxantrone (Mtx), a chemotherapeutic drug; CRT subcellular localization was analyzed by immunofluorescence followed by confocal microscopy. In order to determine NGF effect on Mtx and Tg-induced CRT translocation from the ER to the cell membrane, cells were preincubated with NGF prior to Mtx or Tg treatment and CRT translocation to the cell surface was determined by flow cytometry. In addition, by western blot analyses, we evaluated proteins associated with the CRT translocation pathway, both in A2780 cells and human ovarian samples. We also measured NGF effect on cell apoptosis induced by Mtx. Our results indicate that Mtx and Tg, but not NGF, induce CRT translocation to the cell membrane. NGF, however, inhibited CRT translocation induced by Mtx, while it had no effect on Tg-induced CRT exposure. NGF also diminished cell death induced by Mtx. NGF effect on CRT translocation could have consequences in immunotherapy, potentially lessening the effectiveness of this type of treatment.

Effect of estradiol on the expression of angiogenic factors in epithelial ovarian cancer.

INTRODUCTION: Ovarian cancer presents a high angiogenesis (formation of new blood vessels) regulated by pro-angiogenic factors, mainly vascular endothelial growth factor (VEGF) and nerve growth factor (NGF). An association between endogenous levels of estrogen and increased risk of developing ovarian cancer has been reported. Estrogen action is mediated by the binding to its specific receptors (ERα and ERß), altered ERα/ERß ratio may constitute a marker of ovarian carcinogenesis progression. OBJECTIVE: To determine the effect of estradiol through ERα on the expression of NGF and VEGF in epithelial ovarian cancer (EOC). METHODOLOGY: Levels of phosphorylated estrogen receptor alpha (pERα) were evaluated in well, moderate and poorly differentiated EOC samples (EOC-I, EOC-II, EOC-III). Additionally, ovarian cancer explants were stimulated with NGF (0, 10 and 100 ng/ml) and ERα, ERß and pERα levels were detected. Finally, human ovarian surface epithelial (HOSE) and epithelial ovarian cancer (A2780) cell lines were stimulated with estradiol, where NGF and VEGF protein levels were evaluated. RESULTS: In tissues, ERs were detected being pERα levels significantly increased in EOC-III samples compared with EOC-I (p<0.05). Additionally, ovarian explants treated with NGF increased pERα levels meanwhile total ERα and ERß levels did not change. Cell lines stimulated with estradiol revealed an increase of NGF and VEGF protein levels (p<0.05). CONCLUSIONS: Estradiol has a positive effect on pro-angiogenic factors such as NGF and VEGF expression in EOC, probably through the activation of ERα; generating a positive loop induced by NGF increasing pERα levels in epithelial ovarian cells.

Role of dihydrotestosterone (DHT) on TGF-ß1 signaling pathway in epithelial ovarian cancer cells.

PURPOSE: One of the hypotheses regarding the genesis of epithelial ovarian cancer involves the action of androgens on the proliferation of epithelial ovarian cells, as well as inclusion cysts. The purpose of the present study was to evaluate whether DHT causes changes in the TGF-ß1 pathway that might modify the anti-proliferative effect of the latter. METHODS: The levels of TGF-ß1 protein, of its receptors (TGFBR1 and TGFBR2), of Smad2/3 (canonical signaling pathway protein) and of p21 (cell cycle protein) were assessed in ovarian tissues, epithelial ovarian cancer cell lines (A2780) and control cell lines (HOSE) through the use of immunohistochemistry and immunocytochemistry. Additionally, cell lines were treated with 100 nmol/L DHT, 10 ng/mL of TGF-ß1 and DHT + TGF-ß1 during 72 h in the presence and absence of a siRNA against androgen receptor. After treatment, TGFBR1 and TGFBR2 levels were detected through Western blotting and p21 was assessed through immunocytochemistry. RESULTS: Epithelial ovarian cancer tissues showed a decrease in TGF-ß1 I receptor (p < 0.05) and a change in Smad2/3 protein levels. Additionally, after treatment of cell lines with DHT, protein levels of TGF-ß1 receptors (TGFBR1-TGFBR2) showed a decrease (p < 0.05) that might cause a potential disorder in TGF-ß1 response, represented by the significant decrease in p21 protein levels in the presence of DHT (p < 0.001). CONCLUSIONS: Overall, our results indicate a defect in the canonical TGF-ß signaling pathway in epithelial ovarian cancer caused by androgen action, thus suggesting eventual changes in such tissue proliferation rates.

Tyrosine kinase A receptor (trkA): a potential marker in epithelial ovarian cancer.

OBJECTIVES: To evaluate the role of trkA receptor as a potential tumor marker in serous epithelial ovarian cancer and its relationship with the angiogenic factors expression as vascular endothelial growth factor (VEGF) and nerve growth factor (NGF). Additionally, to examine whether NGF and VEGF secreted by epithelial ovarian cancer (EOC) explants and from epithelial ovarian cancer cell line (A2780) are involved in the process of angiogenesis, such as cellular proliferation, migration and differentiation of the human endothelial cell line (EA.hy926). METHODS: The mRNA levels of VEGF, NGF and trkA receptors were measured using PCR in 60 ovarian samples. Cellular localization and semi-quantitative estimation of VEGF, NGF, total trkA and p-trkA was performed using IHC in epithelial cells. NGF, total trkA and p-trkA protein were also evaluated in endothelial cells from the same tissues. Human endothelial cell line EA.hy926 was cultured with conditioned media obtained from both EOC explants and from the A2780 cell line, with or without NGF stimulus. RESULTS: Significantly higher levels of NGF, total trkA and p-trkA protein expressions were observed in epithelial and endothelial cells in poorly differentiated EOC versus normal ovary. Interestingly, the p-trkA receptor expression level showed the most significant difference and its presence was only found in borderline tumor and EOC samples indicating the importance of trkA receptor in EOC as a potential tumor marker. A significant increase in proliferation, migration and differentiation of EA.hy926 cells was observed with NGF, and this effect was significantly reverted when NGF was immuno-blocked and when a trkA inhibitor was used, showing that NGF is an important angiogenic factor in EOC by activating its trkA receptor. CONCLUSION: These results indicate that p-trkA may be considered as a new potential tumor marker in EOC, and that NGF may also act as a direct angiogenic factor in EOC.

Nerve growth factor and its high-affinity receptor trkA participate in the control of vascular endothelial growth factor expression in epithelial ovarian cancer.

OBJECTIVES: To compare the expression of nerve growth factor (NGF) and its high-affinity receptor trkA in normal ovaries and in epithelial ovarian carcinomas. Given NGF acts as an angiogenic factor through a vascular endothelial growth factor (VEGF)-mediated mechanism in several types of tissues, we examined whether NGF regulates the expression of VEGF isoforms in epithelial ovarian cancer (EOC). METHODS: The expression and localization of NGF and tyrosine kinase receptor A (trkA) in normal ovarian samples and in ovarian cancer samples were analyzed by RT-PCR and immunohistochemistry. NGF regulates the expression of three VEGF isoforms (VEGF(121), VEGF(165) and VEGF(189)); these were examined using RT-PCR in explants of EOC and ELISA in culture media. RESULTS: TrkA mRNA levels were over-expressed in ovarian cancer compared to normal ovarian samples, whereas NGF mRNA levels remained unchanged. NGF and trkA proteins were absent or found in very low levels in normal ovarian surface epithelium (OSE), whereas they were highly expressed in epithelial cells of EOC. Additionally, NGF stimulated the expression of VEGF isoforms in cancer explants. The effect was dose-dependent and inhibited by a NGF antibody and by K(252a), a trk receptor inhibitor. CONCLUSION: The abundance of NGF and trkA receptors in epithelial cells of EOC, together with the ability of NGF to increase VEGF expression strongly suggests an autocrine role of NGF in EOC. These findings suggest that blocking neurotrophin action could be a therapeutic target in treating ovarian cancer.

Surgical management of recurrent cervical cancer.

The majority of patients with recurrent cervical cancer are incurable and treatment is based on the type of primary therapy delivered. Only a very small percentage of the patients with recurrent cervical cancer following primary radiotherapy will have central pelvic recurrences that are amenable to surgical resection and curable by pelvic exenteration. These procedures should be undertaken only after the completion of exhaustive attempts to exclude extrapelvic disease.

Secondary cytoreductive surgery in the patient with recurrent ovarian cancer is often beneficial.

The majority of women with ovarian cancer will present at an advanced stage and ultimately experience a recrudescence of tumor. Recent data indicates that secondary cytoreductive surgery is feasible, well tolerated and associated with significant prolongation of survival in selected patients with recurrent ovarian cancer.