A new system for regulated functional gene expression for gene therapy applications: nuclear delivery of a p16INK4A-estrogen receptor carboxy terminal fusion protein only in the presence of estrogen.

The clinical use of gene therapy requires tight regulation of the gene of interest and functional expression only when it is needed. Thus, it is necessary to develop ways of regulating functional gene expression with exogenous stimuli. Many regulatable systems are currently under development. For example, the tetracycline-dependent transcriptional switch has been successfully employed for in vivo preclinical applications. However, there are no examples of regulatable systems that have been employed in human clinical trials. In the present study, we established an adenovirus-delivered functional gene expression system that is regulated by estrogen. This system uses p16INK4A fused at its C-terminus to the ligand-binding domain of the estrogen receptor (DeltaERalpha). We were able to establish cell lines expressing this gene wherein the functional expression of p16INK4A is estrogen-dependent and causes the arrest of several ovarian cancer cell lines. This inducible and adenovirus-mediated gene transfer system may allow gene therapy using nuclear functioning genes in postmenopausal or ovariectomized women.

Expression of an activated mammalian target of rapamycin in adenocarcinoma of the cervix: A potential biomarker and molecular target therapy.

Alterations of the Akt/mTOR pathway have been observed in numerous types of cancer, thus this pathway represents an exciting new target for molecular therapeutics. We investigated the expression of activated Akt (p-Akt) and mTOR (p-mTOR) in patients with adenocarcinoma of the cervix and the involvement of the p-Akt/p-mTOR pathway in response to combination of inhibitor agents, rapamycin and LY294002, with conventional therapy, cisplatin, in vitro. Immunohistochemistry analysis of p-Akt and p-mTOR was conducted in 26 patients with adenocarcinoma of the cervix. Western blot analysis was performed to determine the protein expression involved in response to chemotherapy in cervical cancer cell lines. The results showed that p-Akt and p-mTOR were identified in 50% and 53.8% of adenocarcinoma of the cervix. The expression of p-mTOR was a significant independent marker for prognosis. A significant correlation between p-Akt and p-mTOR was observed. There was no correlation between their expressions with any of clinicopathological factors. In the in vitro study, cisplatin at CPI(50) targets both the apoptosis and survival pathway by activating the caspase-cascade; inhibiting Akt, mTOR, p70S6K, and 4EBP1. Combination of rapamycin with cisplatin induced synergistic interaction. On the other hand, combination with LY294002 resulted in either synergistic or antagonistic effect depending on the doses given. Rapamycin pretreatment potentiated cisplatin-induced apoptosis cell death and enhanced blocking of the survival pathway. Overall, the expression of p-mTOR is a significant prognostic marker of adenocarcinoma of the cervix and a potential molecular target for the treatment of cervical cancer. Inhibition of the mTOR pathway contributes to cisplatin-induced apoptosis in cervical cancer cell lines.

Clinical and prognostic significance of RhoA and RhoC gene expression in esophageal squamous cell carcinoma.

BACKGROUND: Rho GTPases are involved in the organization of a microfilament network, cell-to-cell interaction, and malignant transformation. To elucidate the role of Rho GTPases in esophageal squamous cell carcinoma (ESCC), we compared the levels of RhoA and RhoC mRNA from ESCC with the corresponding normal tissue originating from the same patients. METHODS: Real-time reverse transcriptase-polymerase chain reaction was performed to observe rhoA and rhoC in esophageal cell lines. Next, the mRNA levels of rhoA and rhoC were evaluated from 50 patients. RESULTS: The rhoA and rhoC were higher in ESCC cell lines than in noncancerous esophageal cell. rhoC was overexpressed in TTn, which was obtained directly from a surgical specimen of a metastatic lesion of ESCC in the mandible. rhoA and rhoC were significantly higher in ESCC patient than in the normal counterparts (P = .0022 and P < .0001, respectively). rhoA correlated with tumor differentiation and rhoC correlated with an advanced tumor, node, metastasis system classifications. rhoA and rhoC in ESCC showed a positive correlation (P = .008). Patients with rhoA overexpression showed a significantly poorer prognosis than those with rhoA underexpression (P = .044). CONCLUSIONS: To our knowledge, this study is the first in which the expression of RhoA and RhoC at the mRNA level in ESCC was examined and compared with its normal counterpart. Our results suggest that rhoA and rhoC are involved in ESCC progression and useful as prognostic markers. Further study will be needed to examine the therapeutic potential of the Rho GTPase inhibitor as a promising anticancer therapy, especially in ESCC.

Chemically synthesized sugar-cholestanols possess a preferential anticancer activity involving promising therapeutic potential against human esophageal cancer.

The understanding of the cell signaling pathways and the molecular events leading to cell death of cancer cells will provide in-depth perspective into the identification and development of potent anticancer agents. A balance between cell proliferation and cell death has been raised as a rational target for the management of malignant tumors. In the present study, the authors demonstrated that chemically synthesized sugar-cholestanols consisting of GlcNAcbeta-, Galbeta- and GlcNAcbeta1,3Galbeta-cholestanols exerted a strong inhibiting activity against cell proliferation of esophageal cancer cells, but cholestanol itself did not show such an activity against the same cancer cells at all. In addition to their predominant role as an antiproliferation agent, evidence based on the molecular analyses suggested that sugar-cholestanols played a regulatory role in multiple signal transduction pathways inducing apoptosis through both the death signal-extrinsic and the mitochondria-intrinsic pathways. Sugar-cholestanols seemed to be more susceptible to esophageal cancer cells than to non-cancerous esophageal cells at the very early event of their exposure and, further, to suppress specifically the expression of vascular endothelial growth factor. Taken together, these novel functions of sugar-cholestanols indicate that they could have promising therapeutic potential against human esophageal cancer.

Expression of carbohydrate antigens in human esophageal squamous cell carcinoma: prognostic application and its diagnostic implications.

BACKGROUND: Tumor markers whose antigenic determinants have been demonstrated to consist of carbohydrates are probably one of the most extensive tools that have been used in routine cancer diagnosis. In this study, the relevance of carbohydrate antigen expression profile was examined in esophageal squamous cell carcinoma together with prognosis in 130 patients. METHODS: The expression of carbohydrate antigens was estimated immunohistochemically by anti-sialyl Lewis a (sialyl Le(a)) and anti-sialyl Lewis x (sialyl Le(x)) monoclonal antibodies, and correlation between their staining and clinicopathological status was examined. In addition, the correlation of both carbohydrate antigens expression was evaluated with microvessel density (MVD). RESULTS: Expressions of sialyl Lewis antigens and MVD were associated with several clinicopathological features that reflect the tumor aggressiveness in esophageal cancer. The 5-year survival rate of patients was found to be associated with expression of sialyl Le(a) and sialyl Le(x) antigens and with MVD; thus, all of them were revealed to be independent prognostic factors. CONCLUSIONS: Combination of these factors offered a better prediction of prognosis of esophageal squamous cell carcinoma. Further, carbohydrate antigens represent a promising target for therapeutic approaches against the disease.

Predictive and prognostic role of activated mammalian target of rapamycin in cervical cancer treated with cisplatin-based neoadjuvant chemotherapy.

The present study was designed to clarify the expression and prognostic significance of activated Akt and mTOR in cervical cancer and their correlation with response to neoadjuvant chemotherapy (NAC). Immunohistochemical analysis for p-Akt and p-mTOR expression was performed on paraffin-embedded biopsy specimens from 25 patients with advanced cervical cancer (stage Ib2-IIb). We correlated this finding with various clinicopathological variables and prognosis by uni- and multivariate analyses. All patients received cisplatin-based NAC, and primary tumor response was evaluated by RECIST criteria and then classified as a positive or negative response. Activation of Akt was detected in the cytoplasm and nucleus of the cancer cells in 12 patients (48%), whereas p-mTOR was detected in the cytoplasm and membrane of the cancer cells in 13 patients (52%). Post NAC evaluation of the primary tumor revealed 68% (17/25) responsive tumors. The expression of p-mTOR and distant metastasis significantly correlated with the response to NAC (p = 0.0101 and p = 0.0107); however, there was no significant correlation between p-Akt and p-mTOR expression and any of the clinicopathological characteristics of the patients. In the univariate analysis, activated Akt and mTOR were found to be significant prognostic indicators (p < 0.05). In multivariate analysis, p-mTOR expression retained its significance as an independent poor prognostic marker (p = 0.0178). In summary, our present study showed that cervical cancer expressed Akt and mTOR activation. Moreover, the expression of phosphorylated mTOR may have a role as a marker to predict response to chemotherapy and survival of cervical cancer patients who are treated with cisplatin-based neoadjuvant chemotherapy. Our results suggest that the mTOR cascade may be a promising target for therapeutic intervention in cervical cancer.

Differential sensitivity of paclitaxel-induced apoptosis in human esophageal squamous cell carcinoma cell lines.

PURPOSE: Paclitaxel is a highly effective chemotherapy agent against adenocarcinomas and squamous cell carcinomas of the esophagus. However, its precise effects in human esophageal cancer cells are not well understood. This study was designed to examine the relationship between cell-cycle phases of paclitaxel-activated checkpoints and to elucidate the molecular pathway of the effect of paclitaxel in human esophageal squamous cell carcinoma (ESCC) cell lines. METHODS: The three human ESCC cell lines--TE-2, TE-13 and TE-14--were examined for their response to paclitaxel. ESCC cells were treated with various concentrations of paclitaxel for 1-3 days using MTT assay. The cell-cycle progression and apoptosis were examined by flow cytometry. DNA fragmentation assay was carried out to confirm the fragmented cells as hallmark for apoptotic cells. In additional, the expression of apoptosis-related proteins in ESCC-treated cells was then examined by Western blot analysis. RESULTS: TE-14 cells demonstrated the highest sensitivity among all cells. G2/M cell-cycle arrest occurs prior to paclitaxel-induced apoptosis in ESCC cells. The fragmentation of chromatin was observed in drug treated TE-13 and TE-14 cells by flow cytometry and DNA ladder formation. In contrast, the measurement for TE-2 cells was more suggestive of phenotype a resistant in response to paclitaxel treatment. Western blot analysis results showed that the mitochondrial pathway might be involved in paclitaxel-induced apoptosis in ESCC cell lines. CONCLUSION: Differential sensitivity was observed in human ESCC cell lines in response to paclitaxel treatment. G2/M arrest occurs with a prior to paclitaxel-induced apoptosis and might be mediated by the mitochondrial (intrinsic) apoptosis pathway in human ESCC cells.