Correlation between HER-2/neu(erbB-2) expression level and therapeutic effect of combination treatment with HERCEPTIN and chemotherapeutic agents in gastric cancer cell lines.

INTRODUCTION: Although advanced gastric cancer has many limitations and response rate is marginal in chemotherapy. Overexpression of human epidermal growth factor receptor 2(HER-2/neu) gene and its protein are associated with increased cell division and a high rate of tumor growth and have been reported in several malignancies. Especially, approximately 30% of breast cancer patients have overexpression of HER-2/neu protein and the overexpression metastasize faster, induces resistance of the chemotherapy and down-regulate function of estrogen receptor. Recombinant humanized anti-HER2 antibody (Herceptin) inhibits proliferation of HER-2/neu overexpressing tumor cells and the use of that in combination in metastatic breast cancer have increased cytotoxicity of chemotherapeutic agents. METHODS: We evaluated the expression of HER-2/neu protein in gastric cell lines by FACS and then comparing the cytotoxicity in chemotherapeutics (doxorubicin, cisplatin, paclitaxel, 5-FU) alone and in combination with Herceptin according to the expression of HER-2/neu protein by MTT assay. RESULTS: 1. NCI-N87 (88%) gastric cancer cell line and SK-BR-3 (89%) breast cancer cell line with strong positivity of HER-2/neu expression. YBC-2 (55%) and YBC-3 (48%) gastric cancer cell line with intermediated, weak positivity respectively. Negative control U-87 MG (6%) brain cancer cell line were showed low expression of HER-2/neu. 2. Cell growth was dose-dependently inhibited in HER-2/neu positive, control cell line SK-BR-3 by Herceptin treatment but not observed in HER-2/neu negative control cell line U-87 MG. Effective growth inhibition was not observed in gastric cancer cell lines with single treatment of Herceptin, all cell lines observed the dose-dependent growth inhibition to chemotherapeutic agents (doxorubicin, cisplatin, paclitaxel and 5-FU). 3. Combination of Herceptin with doxorubicin observed synergistic effects in all cancer cell lines except YBC-3, combination of Herceptin with cisplatin observed NCI-N87 and SK-BR-3 and combination of Herceptin with paclitaxel observed synergistic effects in YBC-2. Combination of Herceptin with 5-FU observed antagonistic effects in all cancer cell lines. CONCLUSIONS: According to HER-2/neu expression level, effect of anti-cancer agents was observed differently in combination of Herceptin with chemotherapeutic agents. This suggests that HER-2/neu expression level can be applied standard of combination drug selection in combination of Herceptin With chemotherapeutic agents in gastric cancer.

Overexpression of Ubiquitin-Specific Protease15 (USP15) Promotes Tumor Growth and Inhibits Apoptosis and Correlated With Poor Disease-Free Survival in Hepatocellular Carcinoma.

USP15 is a member of ubiquitin-specific proteases (USPs, the largest subfamily of deubiquitinases) and functions as a stabilize factor of target proteins in reversible ubiquitiantion progression. Dysregulated expression of USP15 has been observed in various cancers. However the expression profile and regulatory mechanism of USP15 in hepatocellular carcinoma (HCC) remains largely elusive. To exam the USP15 expression changes in the progression of HCC, we performed IHC analysis to test USP15 expression in a series of cancer-prone diseases including 2 normal liver tissues, 6 liver cirrhosis, 16 primary liver lesions and 15 metastases of hepatocellular carcinoma. The expression of USP15 was upregulated in various liver diseases in compared with normal tissue significantly (p < 0.05). Although no significant different of USP15 expression were discovered between cirrhotic tissue and primary tissue, its expression in HCC metastatic tissue was upregulated. Subsequently, we test the USP15 expression profile in a cohort of 66 HCC patients. USP15 expression was positively correlated with the recurrence of HCC significantly (p = 0.004). HCC patients with high USP15 expression had shorter disease free survival time in compare with those with low USP15 expression (56.9% VS 26.7%, P = 0.012). Subsequently, Cox multivariate analyses of clinical factors associated with disease free survival were performed and USP15 expression (p = 0.008) together with tumor size (p = 0.034) were proved to be independent predict factors in HCC. Then, we silenced USP15 expression in HCC cells and the results showed that downregulated USP15 expression resulting proliferation inhibition and apoptosis induction. In conclusion, our results suppose USP15 to be a potential target in HCC.

Prognostic value of T cell immunoglobulin mucin-3 in prostate cancer.

BACKGROUND: Optimal treatment for prostate cancer remains a challenge worldwide. Recently, T cell immunoglobulin mucin-3 (TIM-3) has been implicated in tumor biology but its contribution prostate cancer remains unclear. The aim of this study was to investigate the role of TIM-3 as a prognostic marker in patients with prostate cancer. METHODS: TIM-3 protein expression was determined by immunohistochemistry and Western blotting in 137 prostate cancer tumor samples and paired adjacent benign tissue. We also performed cell proliferation assays using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl- 2H tetrazolium bromide (MTT) and cell invasion assays. The effects of small interfering RNA (siRNA)-mediated knockdown of TIM-3 (TIM-3 siRNA) in two human prostate cancer cell lines were also evaluated. RESULTS: TIM-3 expression was higher in prostate cancer tissue than in the adjacent benign tissue (P<0.001). High TIM-3 expression was an independent predictor of both recurrence-free survival and progression-free survival. TIM-3 protein was expressed in both prostate cancer cell lines and knockdown suppressed their proliferation and invasion capacity. CONCLUSIONS: TIM-3 expression is associated with a poor prognosis in prostate cancer. Taken together, our results indicate that TIM-3 is a potential prognostic marker in prostate cancer.

Identification of differentially expressed genes in gastric cancer by high density cDNA microarray.

The identification of molecular markers for diagnosis, treatment, and prognosis is a significant issue in the management of patients with gastric cancer. We compared the expression profiles of 23 gastric cancers and 22 normal gastric tissues using cDNA microarrays. We divided the samples into two sets, 11 pairs as a training set and 12 unpaired gastric cancer and 11 unpaired normal gastric tissues as a test set. We selected significant genes in the training set and validated the significance of the genes in the test set. We obtained 238 classifier genes that showed a maximum cross-validation probability and clear hierarchical clustering pattern in the training set, and showed excellent class prediction probability in the independent test set. The classifier genes consisted of known genes related to the biological features of cancer and 28% unknown genes. We obtained genome-wide molecular signatures of gastric cancer, which provides preliminary exploration data for the pathophysiology of gastric cancer.

Genetic analysis of liver metastatic cell lines with different metastatic potential.

Metastasis is the major feature of malignant tumors that causes 90% of cancer deaths. Our laboratory has already established liver metastatic clones with YCC-16, isolated from the blood of a gastric cancer patient and expanded in vitro culture using a repeated orthotopic implantation method, and had reported biologic behaviour of the parental YCC-16, the orthotopic primary S1L0, and S1L1, S2L2 and S3L3 liver metastatic clones. Here, using these cell lines, we screened from chromosomal abnormalities using karyotype analysis and micro-CGH matching. There were 31 genes screened using PCA method which were functionally related to cell adhesion. Also, there were 23 genes selected which were related to the liver specific metastasis but excluded genes related to adhesion. There were 4 genes which demonstrated reduced or increased expression stepwise with passage. In conclusion, our results should contribute to exploring the mechanisms of liver metastasis by gastric cancer.