Epigenetic biomarkers in epithelial ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy and the 5th leading cause of cancer death in women. Women with ovarian cancer are typically diagnosed at late stage, when the cancer has spread into the peritoneal cavity and complete surgical removal is difficult. The 5-year survival time for patients diagnosed at this stage is 30%, in contrast to a 5-year survival of 90% for patients diagnosed at early stage. Cancer screening and early detection have the potential to greatly decrease the mortality and morbidity from cancer. The emerging field of epigenetics offers a valuable opportunity to identify cancer-specific DNA methylation changes that can be used in the clinic to improve early-stage diagnosis and better predict response in treated patients.     

Lysophospholipids are potential biomarkers of ovarian cancer.

OBJECTIVE: To determine whether lysophosphatidic acid (LPA) and other lysophospholipids (LPL) are useful markers for diagnosis and/or prognosis of ovarian cancer in a controlled setting. METHOD: Plasma samples were collected from ovarian cancer patients and healthy control women in Hillsborough and Pinellas counties, Florida, and processed at the University of South Florida H. Lee Moffitt Cancer Center and Research Institute (Moffitt). Case patients with epithelial ovarian cancer (n = 117) and healthy control subjects (n = 27) participated in the study. Blinded LPL analysis, including 23 individual LPL species, was performed at the Cleveland Clinic Foundation using an electrospray ionization mass spectrometry-based method. LPL levels were transmitted to Moffitt, where clinical data were reviewed and statistical analyses were performed. RESULTS: There were statistically significant differences between preoperative case samples (n = 45) and control samples (n = 27) in the mean levels of total LPA, total lysophosphatidylinositol (LPI), sphingosine-1-phosphate (S1P), and individual LPA species as well as the combination of several LPL species. The combination of 16:0-LPA and 20:4-LPA yielded the best discrimination between preoperative case samples and control samples, with 93.1% correct classification, 91.1% sensitivity, and 96.3% specificity. In 22 cases with both preoperative and postoperative samples, the postoperative levels of several LPL, including S1P, total LPA, and lysophosphatidylcholine (LPC) levels and some individual species of LPA and LPC, were significantly different from preoperative levels. CONCLUSION: LPA, LPI, LPC, and S1P appear useful as diagnostic and prognostic biomarkers of ovarian cancer.     

KLK6 and KLK13 predict tumor recurrence in epithelial ovarian carcinoma

Background:

The human kallikrein-related peptidase family consists of 15 genes. Twelve of these genes are overexpressed in ovarian cancer and may represent potential markers for diagnosis, prognosis, and/or response to treatment. The aim of this study was to determine the prognostic significance of kallikrein-related peptidase 6 (KLK6) and kallikrein-related peptidase 13 (KLK13) in epithelial ovarian cancer by quantifying gene expression levels with tumour pathology and patient survival data.

Methods:

Total RNA was isolated from 106 patients diagnosed with primary ovarian cancer, as well as 8 normal ovary controls. Samples were analysed by quantitative real-time PCR for KLK6 and KLK13 expression. Correlation between kallikrein gene expression and clinical characteristics was evaluated with the χ²-test. Survival analysis was performed using Kaplan–Meier and Cox proportional hazards regression models.

Results:

Expression levels of both KLK6 and KLK13 mRNA were significantly increased in invasive cancers relative to normal ovaries (P=0.002 and 0.039 respectively). High KLK6 and KLK13 expression was an indicator of poor prognosis, with patients having a shorter recurrence-free survival (P=0.002 and 0.027 respectively). High KLK6 expression was also significantly associated with lower overall survival (P=0.011). When subjected to multivariate analysis, patients with either high KLK6 or KLK13 were 3- and 2.2-fold, respectively, more likely to have a recurrence than patients with low kallikrein expression.

Conclusion:

These data show increased mRNA expression of KLK6 and KLK13 in ovarian cancer compared to normal ovarian tissues. High KLK6 or KLK13 expression in primary ovarian tumours can significantly predict prognosis in terms of recurrence-free survival and overall survival. In all, this study shows KLK6 and KLK13 as potential biomarkers and may be therapeutic targets for treatment of ovarian cancer.     

Sphingosine kinase 1 as a potential therapeutic target in epithelial ovarian cancer

Sphingosine kinase 1 (SK1) is over‐expressed in multiple types of human cancer. SK1 has growth‐promoting effects and has been proposed as a potential therapeutic target. We investigated the therapeutic effects of SK1 inhibition in epithelial ovarian carcinoma (EOC). SK1 siRNA or inhibitors were tested in EOC cell lines, including A2780, SKOV3ip1, A2780‐CP20, SKOV3‐TR, ES2 and RMG2. Cells were treated with SK inhibitor or FTY720, and cell proliferation, apoptosis, angiogenesis and invasion were examined by MTT, FACS, ELISA and wound‐healing assays, respectively. In vivo experiments were performed to test the effects of FTY720 on tumor growth in orthotopic mouse xenografts of EOC cell lines A2780 or SKOV3ip1 and a patient‐derived xenograft (PDX) model of clear cell ovarian carcinoma (CCC). Blocking SK1 with siRNA or inhibitors significantly reduced proliferation, angiogenesis and invasion, and increased apoptosis in chemosensitive (A2780 and SKOV3ip1) and chemoresistant (A2780‐CP20, SKOV3‐TR, ES2 and RMG2) EOC cells. SK1 inhibitors also decreased the intracellular enzymatic activity of SK1. Furthermore, FTY720 treatment significantly decreased the in vivo tumor weight in xenograft models of established cell lines (A2780 and SKOV3ip1) and a PDX model for CCC compared to control (p < 0.05). These results support therapeutic targeting of SK1 as a potential new strategy for EOC.     

MicroRNAs in colorectal cancer: Function, dysregulation and potential as novel biomarkers

Background

MicroRNAs (miRNAs) are short non-coding segments of RNA which are involved in normal cellular development and proliferation. Recent studies have identified altered miRNA expression in both tumour tissues and circulation in the presence of colorectal cancer. These altered expression patterns may serve as novel biomarkers for colorectal cancer. This review explores recent developments in this rapidly evolving field.

Methods

A thorough literature search was performed to identify studies describing miRNA expression in colorectal cancer. Specific areas of interest included miRNA expression patterns in relation to development, diagnosis, progression and recurrence of disease, and potential future therapeutic applications.

Results

MiRNAs are associated with the development and progression of colorectal cancer. These may be either overexpressed or underexpressed (depending on the specific miRNA). Although there are fewer published studies regarding circulating miRNAs, these appear to be reflective of alterations in tissue expression and may have a potential role as minimally invasive biomarkers.

Conclusion

MiRNAs have immense potential for refinement of the current processes for diagnosis, staging and prognostic prediction. They may also provide potential future therapeutic targets in the management of colorectal cancer.     

High-dose 5-fluorouracil and leucovorin as second-line chemotherapy in patients with platinum-resistant epithelial ovarian cancer

A total of 14 patients with platinum-resistant advanced epithelial ovarian cancer were treated with a continuous infusion of high-dose 5-fluorouracil (5-FU, 1200 mg/m² per day) for 2 consecutive days weekly for 4 weeks and, thereafter, every 2 weeks in combination with a push injection of folinic acid (20 mg/m²) given just before 5-FU and after 24 h. No objective response was documented, and only five patients showed stable disease. The median survival was 6.5 months. There was minimal toxicity. This schedule of 5-FU in combination with folinic acid is not effective as second-line chemotherapy in advanced ovarian cancer.     

Human kallikrein gene 11 (KLK11) mRNA overexpression is associated with poor prognosis in patients with epithelial ovarian cancer.

PURPOSE: The purpose of this study was to examine expression levels of the human tissue kallikrein 11 gene (KLK11) in epithelial ovarian tumors and to identify the relationship between KLK11 expression and patient survival. EXPERIMENTAL DESIGN: KLK11 mRNA expression was examined by semiquantitative PCR in 64 epithelial ovarian tumors (7 adenomas, 6 low malignant potential tumors, and 51 adenocarcinomas) and in 10 normal ovaries. Semiquantitative PCR results were correlated with clinicopathologic variables and overall survival. cDNA from human normal tissues and tumor tissues was also analyzed. RESULTS: KLK11 mRNA expression was detected in various human cancer tissues including breast, lung, colon, prostate, pancreas, and ovarian carcinoma. The mean value of relative KLK11 expression ratio was significantly higher in ovarian tumor samples than in normal ovary samples (compared with normal samples: adenoma, P = 0.0006; low malignant potential tumor, P = 0.0049; and carcinoma, P < 0.0001). No statistically significant associations between KLK11 mRNA expression level and clinical stage, histological type, or histological grade were observed. The log-rank test showed that high KLK11 mRNA expression and advanced clinical stage significantly correlated with poor patient survival (P = 0.0185 and P = 0.0043, respectively). High KLK11 mRNA expression and clinical stage remained significantly associated with overall survival (P = 0.0225 and P = 0.0202, respectively) after multivariate analysis. CONCLUSIONS: KLK11 expression may play an important role in ovarian cancer development and act as an independent prognostic marker in ovarian cancer patients.     

Serum sErbB1 and epidermal growth factor levels as tumor biomarkers in women with stage III or IV epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) has a high mortality rate, which is due primarily to the fact that early clinical symptoms are vague and nonspecific; hence, this disease often goes undetected and untreated until in its advanced stages. Sensitive and reliable methods for detecting earlier stages of EOC are, therefore, urgently needed. Epidermal growth factor (EGF) is a ligand for EGF receptor (ErbB1); this receptor is the product of the c-erbB1 proto-oncogene. ErbB1 overexpression is common in human ovarian carcinoma-derived cell lines and tumors, in which overexpression is thought to play a critical role in tumor etiology and progression. Furthermore, ErbB1 overexpression is associated with disease recurrence and decreased patient survival. Recently, we have developed an acridinium-linked immunosorbent assay that detects a approximately 110-kDa soluble analogue of ErbB1, ie., sErbB1, in serum samples from healthy men and women (A. T. Baron, et al., J. Immunol. Methods, 219: 23-43, 1998). Here, we demonstrate that serum p110 sErbB1 levels are significantly lower in EOC patients with stage III or IV disease prior to (P < 0.0001) and shortly after (P < 0.0001) cytoreductive staging laparotomy than in healthy women of similar ages, whereas EGF levels are significantly higher than those of age-matched healthy women only in serum samples collected shortly after tumor debulking surgery (P < 0.0001). We observe that the preoperative serum sErbB1 concentration range of advanced stage EOC patients barely overlaps with the serum sErbB1 concentration range of healthy women. In addition, we show that serum sErbB1 and EGF levels changed temporally for some EOC patients who were surgically debulked of tumor and who provided a second serum sample during the course of combination chemotherapy. Finally, we observe a significant positive association between sErbB1 and EGF levels only in serum samples of EOC patients collected prior to cytoreductive surgery (correlation coefficient = 0.61968; P = 0.0027). These data suggest that epithelial ovarian tumors concomitantly affect serum sErbB1 and EGF levels. In conclusion, these data indicate that serum sErbB1 and EGF (postoperative only) levels are significantly different between EOC patients and healthy women and that altered and/or changing serum sErbB1 and EGF levels may provide important diagnostic and/or prognostic information useful for the management of patients with EOC.     

卵巢癌组织中KLK9基因的表达及其临床意义

目的:探讨KLK9基因mRNA及其蛋白在卵巢癌组织中的表达及其临床意义。方法:采用半定量RT-PCR和免疫组化SP法检测55例卵巢癌组织KLK9mR-NA及蛋白的表达。结果:KLK9蛋白表达位于细胞质,KLK9mRNA及其蛋白表达水平与临床分期有关;早期卵巢癌(Ⅰ、Ⅱ期)KLK9mRNA及蛋白表达水平明显高于晚期(Ⅲ、Ⅳ期),χ2值分别为7·33及8·69,P值分别为0·006及0·0032。但KLK9mRNA及其蛋白表达水平与病理分级及组织学类型无关。结论:KLK9基因表达可能与卵巢癌的恶性度有关,可作为一项检测卵巢癌预后的指标。