Inhibitory effect of a Ras homologue member I on pancreatic cancer and its modulation on epithelium growth factor receptor-Ras-Raf-mitogen-activated protein kinase/extracellular regulated protein kinase/1/2 pathway.

OBJECTIVE: To investigate the regulation of epithelium growth factor receptor (EGFR), pan-Ras, and extracellular regulated protein kinase (ERK) with both a ras homologue member I (ARHI) suppression and epithelium growth factor (EGF) stimulation. METHODS: After identification and implication, the constructed plasmid pIRES2-EGFP-ARHI was transfected into Panc-1. The untransfected cell was also explored as controls. The growth curve was drawn to indicate the proliferation effect of ARHI. EGFR-ELISA was performed to investigate the expression of EGFR. Western blot analysis was used to investigate the expression of protein MAPK/ERK1/2, pan-Ras in Panc-1. RESULTS: The proliferation rate of Panc-1 was inhibited by ARHI compared with both empty plasmid and untransfected cell. The amount of EGFR was parallel in both transfected and untransfected cell but affected by EGF stimulation. The amount of pan-Ras was decreased after ARHI transfection. The optimum concentration of EGF effect on P-ERK was 50 ng/ml. CONCLUSION: Both ARHI and EGF play roles in the EGF-EGFR-Ras-Raf-MAPK/ERK1/2 pathway.

Imprinted tumor suppressor gene ARHI induces apoptosis correlated with changes in DNA methylation in pancreatic cancer cells.

Aplesia Ras homologue member I (ARHI, DIRAS3) is a Ras-related imprinted growth inhibitory gene whose expression is down-regulated in the majority of breast and ovarian cancers. This study investigated the inhibitory function of ARHI in pancreatic cancer. Six pancreatic cancer cell lines, tumor xenografts in nude mice and 20 pancreatic cancer tissue sections were analyzed. ARHI is widely expressed in ductal and acinar cells of normal pancreatic tissue, but is down-regulated or lost in approximately 50% of pancreatic cancers. Aberrant methylation of the ARHI locus was found in five pancreatic cancer cell lines, which exhibited down-regulation or loss of ARHI expression. Hypermethylation was detected in five cell lines (5/5, 100%) at CpG island I, in two cell lines (2/5, 40%) at CpG island II and in four cell lines (4/5, 80%) at CpG island III. Re-expression of ARHI significantly inhibited the growth of pancreatic cancer cells. This inhibition was associated with the induction of apoptosis. Treatment with the demethylating agent 5-aza-2'deoxycytidine (5-aza-dC) restored ARHI mRNA expression, inhibited cell growth and induced apoptosis in PANC-1 and P3 human pancreatic cancer cells in culture. In nu/nu mice, 5-aza-dC also inhibited the growth of PANC-1 xenografts and induced apoptosis, as observed by TUNEL staining. These effects were associated with the re-expression of ARHI protein. Therefore, ARHI may serve as a growth inhibitory gene in a significant fraction of pancreatic cancers. Re-expression of ARHI significantly induced the apoptosis of pancreatic cancer cells. A demethylation agent reduced human pancreatic cancer cell line growth in conjunction with ARHI re-expression.

Combining multiple serum tumor markers improves detection of stage I epithelial ovarian cancer.

OBJECTIVE: Currently available tumor markers for ovarian cancer are still inadequate in both sensitivity and specificity to be used for population-based screening. Artificial neural network (ANN) as a modeling tool has demonstrated its ability to assimilate information from multiple sources and to detect subtle and complex patterns. In this paper, an ANN model was evaluated for its performance in detecting early stage epithelial ovarian cancer using multiple serum markers. METHODS: Serum specimens collected at four institutions in the US, The Netherlands and the United Kingdom were analyzed for CA 125II, CA 72-4, CA 15-3 and macrophage colony stimulating factor (M-CSF). The four tumor marker values were then used as inputs to an ANN derived using a training set from 100 apparently healthy women, 45 women with benign conditions arising from the ovary and 55 invasive epithelial ovarian cancer patients (including 27 stage I/II cases). A separate validation set from 27 apparently healthy women, 56 women with benign conditions and 35 women with various types of malignant pelvic masses was used to monitor the ANN's performance during training. An independent test data set from 98 apparently healthy women and 52 early stage epithelial ovarian cancer patients (38 stage I and 4 stage II invasive cases and 10 stage I borderline ovarian tumor cases) was used to evaluate the ANN. RESULTS: ROC analysis confirmed the overall superiority of the ANN-derived composite index over CA 125II alone (p=0.0333). At a fixed specificity of 98%, the sensitivities for ANN and CA 125II alone were 71% (37/52) and 46% (24/52) (p=0.047), respectively, for detecting early stage epithelial ovarian cancer, and 71% (30/42) and 43% (18/42) (p=0.040), respectively, for detecting invasive early stage epithelial ovarian cancer. CONCLUSIONS: The combined use of multiple tumor markers through an ANN improves the overall accuracy to discern healthy women from patients with early stage ovarian cancer. Analysis of multiple markers with an ANN may be a better choice than the use of CA 125II alone in a two-step approach for population screening in which a secondary test such as ultrasound is used to keep the overall specificity at an acceptable level.

Preoperative sensitivity and specificity for early-stage ovarian cancer when combining cancer antigen CA-125II, CA 15-3, CA 72-4, and macrophage colony-stimulating factor using mixtures of multivariate normal distributions.

PURPOSE: In CA-125-based ovarian cancer screening trials, overall specificity and screening sensitivity of ultrasound after an elevated CA-125 exceeded 99.6% and 70%, respectively, thereby yielding a positive predictive value (PPV) exceeding 10%. However, sensitivity for early-stage disease was only 40%. This study aims to increase preoperative sensitivity for early-stage ovarian cancer while maintaining the annual referral rate to ultrasound at 2% by combining information across CA-125II, CA 15-3, CA 72-4, and macrophage colony-stimulating factor (M-CSF). For direct comparisons between marker panels, all sensitivity results correspond to a 98% fixed first-line specificity (referral rate 2%). PATIENTS AND METHODS: Logistic regression, classification tree, and mixture discriminant analysis (MDA) models were fit to a training data set of preoperative serum measurements (63 patients, 126 healthy controls) from one center. Estimates from the training set applied to an independent validation set (60 stage I to II patients, 98 healthy controls) from two other centers provided unbiased estimates of sensitivity. RESULTS: Preoperative sensitivities for early-stage disease of the optimal panels were 45% for CA-125II; 67% for CA-125II and CA 72-4; 70% for CA-125II, CA 72-4, and M-CSF; and 68% for all four markers (latter two results using MDA). CONCLUSION: Efficiently combining information on CA-125II, CA 72-4, and M-CSF significantly increased preoperative early-stage sensitivity from 45% with CA-125II alone to 70%, while maintaining 98% first-line specificity. Screening trials with these markers using MDA followed by referral to ultrasound may maintain previously high levels of specificity and PPV, while significantly increasing early-stage screening sensitivity. MDA is a useful, biologically justified method for combining biomarkers.