Adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colon cancer at high risk of peritoneal carcinomatosis; the COLOPEC randomized multicentre trial

Background: The peritoneum is the second most common site of recurrence in colorectal cancer. Early detection of peritoneal carcinomatosis (PC) by imaging is difficult. Patients eventually presenting with clinically apparent PC have a poor prognosis. Median survival is only about five months if untreated and the benefit of palliative systemic chemotherapy is limited. Only a quarter of patients are eligible for curative treatment, consisting of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CR/HIPEC). However, the effectiveness depends highly on the extent of disease and the treatment is associated with a considerable complication rate. These clinical problems underline the need for effective adjuvant therapy in high-risk patients to minimize the risk of outgrowth of peritoneal micro metastases. Adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) seems to be suitable for this purpose. Without the need for cytoreductive surgery, adjuvant HIPEC can be performed with a low complication rate and short hospital stay. Methods/Design: The aim of this study is to determine the effectiveness of adjuvant HIPEC in preventing the development of PC in patients with colon cancer at high risk of peritoneal recurrence. This study will be performed in the nine Dutch HIPEC centres, starting in April 2015. Eligible for inclusion are patients who underwent curative resection for T4 or intra-abdominally perforated cM0 stage colon cancer. After resection of the primary tumour, 176 patients will be randomized to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy in the experimental arm, or to systemic chemotherapy only in the control arm. Adjuvant HIPEC will be performed simultaneously or shortly after the primary resection. Oxaliplatin will be used as chemotherapeutic agent, for 30 min at 42-43 degrees C. Just before HIPEC, 5-fluorouracil and leucovorin will be administered intravenously. Primary endpoint is peritoneal disease-free survival at 18 months. Diagnostic laparoscopy will be performed routinely after 18 months postoperatively in both arms of the study in patients without evidence of disease based on routine follow-up using CT imaging and CEA. Discussion: Adjuvant HIPEC is assumed to reduce the expected 25 % absolute risk of PC in patients with T4 or perforated colon cancer to a risk of 10 %. This reduction is likely to translate into a prolonged overall survival

Integrated analysis of DNA methylation and gene expression reveals specific signaling pathways associated with platinum resistance in ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Cisplatin and carboplatin are the primary first-line therapies for the treatment of ovarian cancer. However, resistance to these platinum-based drugs occurs in the large majority of initially responsive tumors, resulting in fully chemoresistant, fatal disease. Although the precise mechanism(s) underlying the development of platinum resistance in late-stage ovarian cancer patients currently remains unknown, CpG-island (CGI) methylation, a phenomenon strongly associated with aberrant gene silencing and ovarian tumorigenesis, may contribute to this devastating condition.</p> <p>Methods</p> <p>To model the onset of drug resistance, and investigate DNA methylation and gene expression alterations associated with platinum resistance, we treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After several cycles of drug selection, the isogenic drug-sensitive and -resistant pairs were subjected to global CGI methylation and mRNA expression microarray analyses. To identify chemoresistance-associated, biological pathways likely impacted by DNA methylation, promoter CGI methylation and mRNA expression profiles were integrated and subjected to pathway enrichment analysis.</p> <p>Results</p> <p>Promoter CGI methylation revealed a positive association (Spearman correlation of 0.99) between the total number of hypermethylated CGIs and GI₅₀values (<it>i.e</it>., increased drug resistance) following successive cisplatin treatment cycles. In accord with that result, chemoresistance was reversible by DNA methylation inhibitors. Pathway enrichment analysis revealed hypermethylation-mediated repression of cell adhesion and tight junction pathways and hypomethylation-mediated activation of the cell growth-promoting pathways PI3K/Akt, TGF-beta, and cell cycle progression, which may contribute to the onset of chemoresistance in ovarian cancer cells.</p> <p>Conclusion</p> <p>Selective epigenetic disruption of distinct biological pathways was observed during development of platinum resistance in ovarian cancer. Integrated analysis of DNA methylation and gene expression may allow for the identification of new therapeutic targets and/or biomarkers prognostic of disease response. Finally, our results suggest that epigenetic therapies may facilitate the prevention or reversal of transcriptional repression responsible for chemoresistance and the restoration of sensitivity to platinum-based chemotherapeutics.</p

Cyclooxygenase-2 is an essential mediator of gonadotropins-induced apoptosis of human ovarian surface epithelial cells

Objective: To investigate the signaling mechanism underlying gonadotropins-mediated apoptosis of human ovarian surface epithelial (OSE) cells. Methods: OSE cells were treated with surge concentrations of gonadotropins (FSH and LH/hCG), membrane, cytosolic, and nuclear fractions were prepared by differential centrifugation. Expression of N-cadherin, b-catenin, and cyclooxygnease-2 (COX-2) were examined by immunoblot analysis. b-catenin/T-cell factor (TCF) transcriptional activity was measured in a luiferase reporter gene assay. Results: We demonstrated that disruption of N-cadherin-mediated cell-cell adhesion by gonadotropins is an important molecular event in the apoptosis in human OSE. This downregulation of N-cadherin was correlated with a redistribution of b-catenin from the plasma membrane to the nucleus, resulting in the activation of b-catenin/T Cell Factor (TCF) transcription. These events were mediated via a phosphatidylinositol 3-kinase (PI3K)-dependent phosphorylation of the inhibitory serine 9 residue of glycogen synthase kinase-3b (GSK3-b). In addition, we showed that COX-2, a target of b-catenin/TCF, is an important mediator of the gonadotropins-induced apoptosis of OSE. Conclusion: These findings shed new light on the molecular mechanism underlying OSE survival and death, a process that is anticipated to have important implication in the ovulation and ovarian cancer risk

Gonadotropin and its role in the β-catenin/T-cell factor signaling pathway

Gonadotropins, follicle-stimulating hormone and luteinizing hormone are key regulators in ovarian function, acting in an endocrine manner to regulate gametogenesis and steroidogenesis. In addition to normal tissue, gonadotropin receptors have also been demonstrated in ovarian carcinoma cell lines and primary tumors, suggesting that the gonadotropins may play a role in the pathophysiology of ovarian cancer. Thus, understanding mechanisms involved in signaling transduction by the gonadotropin receptors are of considerable interest and potential significance. In the ovary, gonadotropins initiate their cellular responses by binding to their G-protein-coupled receptors and activation of specific downstream intracellular effectors and signal pathways, including those of protein kinases A and C and mitogen-activated protein kinase. Recently, gonadotropins were shown to stimulate nuclear accumulation of β-catenin, which controls lymphoid-enhancing factor/ T-cell factor family-sensitive gene expression. β-catenin has a pivotal function in the control of cell fate. The ability of gonadotropins to regulate β-catenin provides a new dimension of knowledge linking pituitary hormones to the β-catenin signaling in normal ovarian physiology and demonstrating how its dysregulation can contribute to the development of ovarian cancer. © 2007 Future Drugs Ltd.link_to_subscribed_fulltex

p70S6K induces epithelial to mesenchymal transition in human ovarian cancer cells through upregulation of Snail

Background: Epithelial ovarian cancer is the most lethal gynecological malignancy and is a highly metastatic cancer characterized by widespread peritoneal dissemination and ascites. The 70 kDa S6 kinase (p70S6K) is a downstream effector of the phosphatidylinositol 3-kinase/AKT/mTOR pathway, which is frequently activated in human ovarian cancer. We recently demonstrated a novel role of p70S6K in the invasion of ovarian cancer cells. Since epithelial-to-mesenchymal transition (EMT) is a critical step contributing to tumor invasiveness, we hypothesized that p70S6K activation induced molecular alterations that mediate EMT. Materials and Methods: To examine the roles of p70S6K, constitutively active forms of p70S6K were transfected into the ovarian cancer cell lines, and the consequence of their transfection was investigated. Optical microscopy was used to assess changes in cell morphology and behavior. Western blot, reverse transcription (RT)-PCR, and reporter gene assays were employed to measure the expression and activity of epithelial and mesenchymal markers. Results: We showed that ovarian cancer cells expressed constitutively active p70S6K underwent phenotypic changes consistent with EMT: the cells lost epithelial cell morphology, acquired fibroblast-like properties, and showed reduced intercellular adhesion. Western blot and RT-PCR revealed strong reduction of the epithelial marker E-cadherin expression and activation of mesenchymal markers vimentin and N-cadherin in p70S6Kexpressing cells. Consistently, p70S6K downregulation by small interfering RNA (siRNA) or the specific mTOR/p70S6K inhibitor rapamycin caused the reversion to an epithelial phenotype, in which E-cadherin was relocalized to the plasma membrane. In addition, active p70S6K induced upregulation of Snail, a repressor of E-cadherin and an inducer of the EMT, which could be reverted by siRNA-mediated repression of p70S6K, indicating that p70S6K-induced EMT depends on Snail. We also showed that p70S6K enhanced Snail activity through inactivation of glycogen synthase kinase 3beta (GSK3b), as expression of constitutively active GSK3b blocked p70S6K-dependent Snail activation. Conclusion: Our study indicates, for the first time, that activation of p70S6K mediates EMT through upregulation of Snail via GSK3b. These findings not only expand the spectrum of biological activities of p70S6K but also suggest that therapeutic inhibition of p70S6K may be a useful strategy to control ovarian tumor invasion and metastasis (supported by RGC HKU7599/05M).link_to_OA_fulltex