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Aim: The current phase II clinical study was conducted to evaluate the efficacy and safety of weekly docetaxel alone, and weekly docetaxel-plus-oxaliplatin, as a second-line chemotherapy in patients with cisplatin-refractory advanced gastric cancer., Patients and Methods: We enrolled patients with histologically confirmed gastric adenocarcinoma whose disease had progressed after cisplatin-based regimens. Patients were randomly assigned to receive docetaxel alone (36 mg/m(2), days 1 and 8) or docetaxel (36 mg/m(2), days 1 and 8) and oxaliplatin (80 mg/m(2), day 1) combination therapy every three weeks., Results: This trial was terminated early due to poor patient accrual rate. From January 2009 to January 2012, a total of 52 patients were enrolled in the current study from six centers: 27 patients in the docetaxel monotherapy arm and 25 patients in the docetaxel/oxaliplatin combination arm. Fifty-two patients were assessable for efficacy, and response rates as follows (response rate: 14.8% in the monotherapy arm, 24.0% in the combination arm; disease control rate: 48.1% in the monotherapy arm, 76.0% in the combination arm. The median progression-free survival was 2.0 (95% confidence interval=1.2-2.9) months in the monotherapy arm and 4.9 (95% confidence interval=3.6-6.6) months in the combination arm (p=0.002). The most common grade 3 or 4 adverse event was neutropenia (14% for monotherapy versus 32% for combination). No treatment-related mortality was observed., Conclusion: Weekly docetaxel and weekly docetaxel-plus-oxalipaltin regimens were found to be well-tolerated and effective as a second-line chemotherapy for patients with advanced gastric cancer., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

RhoGDP dissociation inhibitor 2 (RhoGDI2) has been identified as a regulator of tumor metastasis; however, its role in cancer remains controversial. The aims of this study were to analyze RhoGDI2 in gastric cancer growth and metastasis, and to determine its possible signaling pathway. The level of expression of RhoGDI2 was further confirmed by real time RT-RCR and Western blot analysis. Transfection of cells with RhoGDI2 shRNA resulted in no effects of cell proliferation, as determined with MTT assays. In an in vitro invasion assay, significantly fewer cells transfected with RhoGDI2 shRNA, compared with control cells, were able to invade across a Matrigel membrane barrier. The role of RhoGDI2 in the level of HGF-induced up-regulation of vascular endothelial growth factor (VEGF) was measured by knockdown of RhoGDI2 with RhoGDI2 shRNA and a chromatic immuno-precipitation assay. The levels of RhoGDI2 and VEGF were up-regulated in cells treated with HGF in a dose-dependent manner. HGF-induced up-regulation of VEGF was repressed by RhoGDI2 knockdown. HGF-induced upregulation of phosphorylated ERK and P38 levels was inhibited in RhoGDI2 knockdown cells. HGF enhanced the binding activity of RhoGDI2 to the VEGF promoter in control cells, but not in RhoGDI2-shRNA cells. Findings of this study also showed a statistically significant difference in the mean RhoGDI2 level before and after surgery (p < 0.01) and the mean level of RhoGDI2 before surgery showed a statistically significant difference depending on lymphatic, neural invasion and stage (p < 0.05). In conclusion, RhoGDI2 might play an important role in up-regulation of VEGF induced by HGF and contributes to HGF-mediated tumor invasion and metastasis, which may serve as a promising target for gastric cancer therapy.

The potential of hepatocyte growth factor (HGF) to regulate the expression of urokinase plasminogen activator (uPA) in a gastric cancer cell is not widely acknowledged. To identify the genes associated with the plasminogen activator proteolytic axis by HGF, we used cDNA microarray technology and selected genes upregulated or downregulated in two gastric cell lines (NUGC-3 and MKN-28). First, IL-1β RNA and protein were confirmed to be upregulated. Then, we investigated the effect of IL-1β induced by HGF on the uPA system, facilitating the migration and invasion of cancer cells in the metastatic process. The role for IL-1β in HGF-induced upregulation of uPA was determined by knockdown of IL-1β with IL-1β shRNA and a chromatin immune precipitation assay. The levels of IL-1β and uPA were upregulated in cells treated with HGF in a dose-dependent manner. HGF-induced upregulation of uPA was suppressed by IL-1β knockdown. HGF enhanced the binding activity of NF-κB to the uPA promoter in control cells, but not in the IL-1β shRNA cells. We confirmed the functional role of HGF inactivation of the uPA promoter by a reporter gene assay. Downregulation of IL-1β using IL-1β shRNA also decreased cell proliferation and in vitro cell invasion. IL-1β stimulated uPA expression through ERK and NF-κB in gastric cancer, which may therefore be promising targets for gastric cancer therapy.

Survivin, a member of the inhibitors of apoptosis protein family, is expressed during development and in various human cancers. However, the clinical relevance of survivin in cancer is still a matter of debate. Genes induced by hepatocyte growth factor (HGF) were screened using cDNA microarray technology in the stomach cancer cell lines, NUGC3 and MKN28. The levels of JunB, survivin, and uro-plasminogen activator (uPA) were up-regulated in cells treated with HGF in a dose-dependent manner. HGF-induced up regulation of JunB, survivin, and uPA was inhibited by pre-treatment with a MEK inhibitor (PD 98059). HGF-induced up-regulation of uPA was repressed by survivin knockdown. HGF enhanced the binding activity of JunB to the survivin promoter in control cells, but not in the JunB-shRNA cells. Transfection with survivin- shRNA resulted in a decrement of cell proliferation, as determined with MTT assays. In an in vitro invasion assay, significantly fewer cells transfected with survivin shRNA than control cells were able to invade across a Matrigel membrane barrier. In conclusion, survivin appeared to play an important role in the up-regulation of uPA induced by HGF via JunB and might contribute to HGF-mediated tumor invasion and metastasis, which may serve as a promising target for gastric cancer therapy.

Objective: The present study was conducted to evaluate the efficacy and safety of a combination regimen of S-1, paclitaxel plus cisplatin in patients with advanced gastric cancer., Methods: Patients with previously untreated metastatic or recurrent, measurable gastric cancer received intravenous paclitaxel 80 mg/m² plus cisplatin 30 mg/m² on days 1, 8 and S-1 35 mg/m² orally twice daily on days 1-14 based on a 3-week cycle., Results: Forty-four patients were enrolled in the current study, among whom 38 were assessable for efficacy and all assessable for toxicity. Two complete response and 24 partial responses were confirmed, giving an overall response rate of 59.1%. At a median follow-up of 11.4 months, the median time to progression and median overall survival was 9.4 (95% CI 6.8-12.1) months and 11.2 (95% CI 7.6-14.8) months, respectively. Grade 3/4 neutropenia occurred in 45 events (20.9%) and febrile neutropenia was observed in five events (2.3%). The common non-hematologic toxicity was nausea (grade 1/2, 27.2%) and diarrhea (grade 1/2, 9.0%)., Conclusion: The combination of S-1, paclitaxel and cisplatin was found to be well tolerated and effective in patients with advanced gastric cancer.

Histone acetylation and deacetylaion play important roles in chromatin remodeling and gene expression. An imbalance of these reactions leads to aberrant behavior of the cells in the cell cycle, which in turn contributes to carcinogenesis. Histone deacetylase (HDAC) inhibitors have been shown to have anti-tumor effects in clinical trials. However, the exact mechanisms by which HDAC inhibitors exert anti-tumor effects and modulate gene expression are not completely understood, and remain a subject of intense investigation. In the current study, we determined whether HDACs regulate urokinase plasminogen activator (uPA), matrix metalloproteinase-9 (MMP-9), and tumor invasion. Using cDNA microarray analysis, we found that hepatocyte growth factor (HGF) induced HDAC5 expression in gastric cancer cell lines, NUGC-3 and MKN-28. TSA, a HDAC inhibitor, decreased HGF-induced HADC-5 expression and also repressed uPA and MMP-9 expression. TSA inhibited cell proliferation in both cell lines. In vitro Matrigel invasion assays showed that the HDAC inhibitor decreased cancer cell invasion. Furthermore, GO6976, a PKC inhibitor, significantly inhibited not only HGF-induced HDAC5 expression but also cell invasion. These results demonstrated that HDACs regulate HGF-induced uPA and MMP-9 expression through a PKC-dependent signal pathway in gastric cancer cells. Our data probably suggest that such activities serve as anti-tumor mechanisms of the HDAC inhibitor.

Hepatoma-derived growth factor (HDGF) is highly expressed in tumor cells and may play an important role in the development and progression of carcinomas. However, the molecular mechanism by which HDGF participates in gastric carcinomatosis requires further analysis. In this study, we determined the role of HDGF in tumorigenesis and elucidated the mechanisms of action. To determine aggressive biological behavior, we knocked down HDGF expression with HDGF-specific shRNA in two gastric cancer cell lines. First, using cDNA microarrary, we showed that hepatocyte growth factor (HGF) induced HDGF and confirmed this by Western blotting. HGF increased HDGF in a dose-dependent manner. We also determined whether HDGF induces angiogenic factor, and found the vascular endothelial growth factor (VEGF) was induced by HDGF. Downregulation of HDGF resulted in a decrement of VEGF. HDGF knock-down was found to induce the expression of the proapoptotic protein, Bad, and also inactivate ERK, which in turn led to dephosphorylation of Bad at ser112 and ser136, and induced apoptosis. Transfection with HDGF-siRNA resulted in a decrement of cell proliferation, as determined with a MMT assay. In an in vitro invasion assay, significantly fewer cells transfected with HDGF-siRNA than control cells were able to invade across a Matrigel membrane barrier. Our results suggest that HDGF is involved in cell growth, cell invasion, and apoptosis. These qualities may contribute to the HDGF-associated aggressive biological behavior of gastric cancer and thus serve as a potential target for cancer therapy.

Purpose: The present study analyzed the polymorphisms of apoptosis-related genes and their impact on the response to chemotherapy and survival of patients with advanced gastric cancer., Patients and Methods: Fifty-seven patients with advanced gastric cancer treated with paclitaxel and cisplatin combination chemotherapy were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue, and the single nucleotide polymorphisms (SNPs) of ten apoptosis-related genes [LTA, TP53, BCL2L11, BID, FASL, caspase 3, caspase 6, caspase 7, and caspase 9] determined using a polymerase chain reaction-restriction fragment length polymorphism assay., Results: The Arg/Pro and Pro/Pro genotypes of TP53 codon 72 were significantly correlated with a lower response rate to the combination chemotherapy when compared to the Arg/Arg genotype (35.7 vs. 66.7%, P-value 0.019) in a logistic regression analysis. A multivariate survival analysis also showed that the time to progression for the patients with the Arg/Pro and Pro/Pro genotypes of TP53 codon 72 was worse than for the patients with the Arg/Arg genotype (Hazard ratio = 3.056, P-value = 0.047), whereas the overall survival was not significantly different., Conclusion: The TP53 codon 72 SNP was found to be predictive of the response to chemotherapy and correlate with the time to progression in patients with advanced gastric cancer treated with paclitaxel and cisplatin chemotherapy.

The proteasome plays a pivotal role in controlling cell proliferation, apoptosis, and differentiation in a variety of tumor cells. Bortezomib is a boronic acid dipeptide derivative, which is a selective and potent inhibitor of the proteasome and has prominent effects in vitro and in vivo against several solid tumors. We examined the anti-proliferative and apoptotic effects of bortezomib in three gastric cancer cell lines (SNU638, MUGC-3 and MKN-28), along with its antitumor combination effects with other chemotherapeutic agents. Tumor cell growth inhibition and apoptosis was measured by MTT assay and FACS analysis, respectively. Apoptosis- and cell cycle-associated protein expression levels were measured by Western blot assay. Bortezomib induced the suppression of tumor cell growth and apoptosis in a dose-dependent manner with an inhibitory dose (ID)50 of approximately 0.5 microg/ml in all gastric cancer cell lines tested. Further combination treatment with cisplatin and docetaxel, in particular with docetaxel displayed dramatically increased tumor cell growth suppression in all three gastric cancer cell lines, as compared to single drug treatment alone. This was concomitant with the induction patterns of apoptotic cells. Bortezomib treatment increased the Bax protein expression. Moreover, combination treatment of bortezomib plus docetaxel resulted in a dramatic increase in the Bax expression. In contrast, Bcl-2 expression was decreased by combination treatment with bortezomib plus docetaxel in SNU638 cells. Finally, bortezomib, docetaxel and to a greater degree bortezomib plus docetaxel increased the expression levels of p27 proteins even without influencing p53 expression levels. Bortezomib has profound effects on tumor cell growth inhibition and induction of apoptosis in human gastric cancer cells, suggesting that bortezomib may be an effective therapeutic drug for patients with gastric cancer. Further combination studies with other chemotherapeutic drugs, in particular docetaxel showing more tumor cell growth inhibition and apoptosis suggest that combining bortezomib with docetaxel might be more effective for displaying tumor cell growth inhibitory effects in gastric cancer cells through regulation of Bcl-2, Bax and p27 proteins in vitro.

Hepatocyte growth factor (HGF) is one of the survival factors with a potent ability to promote cell survival by inhibiting apoptosis. However, the mechanism by which HGF inhibits apoptosis is not completely understood. To explore the genes associated with stomach cancer cell survival by HGF, we used cDNA microarray technology and selected 26 genes up- or downregulated in NUGC-3 cells during HGF treatment. Among them, BAD was confirmed to be upregulated at the RNA and protein levels by HGF treatment. We investigated the effect of BAD induced by HGF on cell survival. HGF treatment inhibited apoptosis induced by BAD overexpression and enhanced BAD phosphorylation. Pretreatment of NUGC-3 cells with PI3K inhibitors, LY 294002, decreased HGF-induced BAD phosphorylation on Ser136 whereas an MEK inhibitor, PD 98059, decreased BAD phosphorylation on Ser112. In conclusion, increases in BAD levels as well as BAD phosphoryation by HGF might contribute to HGF-mediated cell survival in NUGC-3 cells.

We investigated whether the abnormal expression of E-cadherin (ECD), in conjunction with the overexpression of matrix metalloproteinase-7 (MMP-7), is correlated with clinicopathological parameters such as metastasis and the prognosis for human gastric carcinoma. Using RT-PCR, we examined the expression of ECD and MMP-7 mRNA in 42 gastric carcinoma tissues and in the surrounding non-neoplastic mucosa. The macroscopic and histopathological tumor findings and the survival rates were obtained from the patient records. The level of ECD mRNA expression was lower in most of the neoplasms as compared to the corresponding non-neoplastic tissues (50 vs. 80.9%, respectively). The abnormal expression of ECD mRNA was significantly correlated to the microscopic classification and lymph node metastases (p<0.05), and its stage (p<0.05). The level of MMP-7 mRNA expression was higher in most neoplasms compared to the corresponding non-neoplastic tissues (66.6 vs. 50%, respectively). The overexpression of MMP-7 mRNA was significantly correlated with the microscopic classification, lymph node metastases (p<0.05), and its stage (p<0.01). However, a correlation between the abnormal expression of ECD and the overexpression of MMP-7 was not obtained. The survival rate of the patients with an ECD mRNA expression was longer than that of the patients without this expression, but this finding was not statistically significant (p=0.2162). The survival rates of patients with MMP-7 mRNA expression was significantly shorter than that of the patients without MMP-7 mRNA expression (p=0.0025). Overexpression of MMP-7 may be considered as a useful marker for determining metastasis and the prognosis of human gastric carcinoma rather than the abnormal expression of E-cadherin.

The regulatory mechanisms for the proliferation and the particular invasive phenotypes of stomach cancers are not still fully understood. Up-regulations of hepatocytes growth factor (HGF), its receptor (c-Met), and urokinase-type plasminogen activator (uPA) are correlated with the development and metastasis of cancers. In order to investigate roles of HGF/c-Met signaling in tumor progression and metastasis in stomach cancers, we determined effects of a specific MEK1 inhibitor (PD098059) and a p38 kinase inhibitor (SB203580) on HGF-mediated cell proliferation and uPA expression in stomach cancer cell lines (NUGC-3 and MKN-28). HGF treatment induced the phosphorylations of ERK and p38 kinase in time- and dose- dependent manners. Pre-treatment with PD098059 reduced HGF-mediated cell proliferation and uPA secretion. In contrast, SB203580 pre-treatment enhanced cell proliferation and uPA secretion due to induction of ERK phosphorylation. Stable expression of dominant negative-MEK1 in NUGC-3 cells showed a decrease in HGF-mediated uPA secretion. These results suggest that interaction of a MEK/ERK and a p38 kinase might play an important role in proliferation and invasiveness of stomach cancer cells.

The current phase II study was conducted to evaluate the response rate and safety of a combination regimen of biweekly irinotecan plus cisplatin in pretreated patients with advanced gastric cancer. Patients with previously treated metastatic or recurrent gastric cancer received intravenous irinotecan 70 mg/m2 and cisplatin 30 mg/m2 on day 1 and 15 every 4-week cycle. Thirty-two patients were enrolled in the current study. Of these, 31 patients were assessable for efficacy and all for toxicity. No complete response and 5 partial responses were confirmed, giving an overall response rate of 15.6% (95% CI; 2.3-28.9%). The median time to progression and median overall survival for all patients was 113 days and 184 days, respectively. Grade 3/4 neutropenia occurred in 6 patients (18.8%), yet no febrile neutropenia was observed. In addition, grade 3 anorexia was observed in 4 patients (12.5%) and grade 3 diarrhea occurred in 2 patients (6.2%). The combination chemotherapy of biweekly irinotecan and cisplatin was found to be moderately effective and well tolerated in pretreated patients with advanced gastric cancer. Accordingly, this regimen can be regarded as an important second-line treatment option for advanced gastric cancer.

Background: Although many treatments for advanced gastric cancer have been developed, only poor treatment results have generally been obtained. We performed a prospective study on the combination chemotherapy of paclitaxel and cisplatin (PC). The primary objectives of the study were elucidating the disease response and evaluating the drug regimen's safety., Methods: Patients with metastatic or recurrent gastric cancer received intravenous paclitaxel 175 mg/m2, and cisplatin 70 mg/m2 on day 1. This cycle was repeated every 3 weeks., Results: From January 2000 to March 2004, 37 patients from 3 different hospitals were enrolled in this study. A total of 135 treatment cycles (median: 3 cycles) were administered. The responses were evaluable in 34 patients; 24 patients received this regimen as their first-line treatment for metastatic cancer and the other patients received it as their second-line treatment for recurrent cancer. The objective response rate (RR) was 26.5% (95% CI: 11.7-41.3) with two complete responses, and stable disease was observed in 41.1% of the patients. Importantly, an RR of 33.3% (95% CI: 0.6-66.0) was achieved for the eight patients who received this regimen as a first-line treatment. The median follow up duration was 14 months for all the patients, and the median time to progression was 6 months (95% CI: 1.9-10.2). The overall survival time was 8.9 months (95% CI: 7.0-11.0) with a 1-year survival rate of 18.7% (95% CI: 5.6-31.8). The most common toxicity was neutropenia., Conclusion: PC exhibited promising activity against gastric cancer for the previously untreated patients as a first-line treatment with an acceptable toxicity profile.