Double strand RNA-guided endogeneous E-cadherin up-regulation induces the apoptosis and inhibits proliferation of breast carcinoma cells in vitro and in vivo.

E-cadherin plays a crucial role in epithelial cell-cell adhesion and in the maintenance of tissue architecture. Down-regulation of E-cadherin expression correlates with a strong invasive potential, resulting in poor prognosis in many human carcinomas, including breast cancer. Restoration of E-cadherin can inhibit cell invasion and metastasis in many types of tumors. It has been demonstrated that promoter hypermethylation causes transcriptional down-regulation of E-cadherin. Here, using an RNAa technique specifically activating the expression of E-cadherin through transcriptional regulation, we assessed the phenotype changes of a breast carcinoma cell line with transfection of small-activating RNAs (saRNAs). We observed cell apoptosis, proliferation inhibition and reduction in human breast cancer migration in vitro. Animal experiment results showed that saRNA could inhibit tumor growth in vivo compared with scramble double-small RNA (dsRNA).This study provides a new potential strategy for breast cancer therapy, and also demonstrates the potential for saRNA as a therapeutic option for enhancing tumor suppressor gene expression in breast cancer. (Cancer Sci 2010).

Gene therapy with RNAi targeting UHRF1 driven by tumor-specific promoter inhibits tumor growth and enhances the sensitivity of chemotherapeutic drug in breast cancer in vitro and in vivo.

UHRF1, also known as ICBP90 (inverted CCAAT box binding protein 90) in human, is a nuclear protein that acts as a fundamental regulator in cell proliferation and maintains DNA methylation. It is reported that UHRF1 is obviously upregulated in various human malignancies, but unchanged in differentiated tissues, suggesting that UHRF1 plays a crucial role in carcinogenesis and can be a useful anticancer drug target. In this study, we explored whether UHRF1 can be a therapeutic target for human breast carcinoma. We successfully constructed the tumor-specific shRNA expression vector driven by survivin promoter targeting UHRF1 gene. The tumor-specific RNA interference system efficiently and specifically knocked down UHRF1 expression, induced the apoptosis of tumor cells, and enhanced chemosensitivity of tumor cells to cisplatinum, but not in normal cells in vitro and in vivo. Therefore, the survivin promoter-driving shRNA expression system targeting UHRF1 may play a vital and potential role for the treatment of specificity and high efficacy in human breast carcinomas.

Long-term and stable correction of uremic anemia by intramuscular injection of plasmids containing hypoxia-regulated system of erythropoietin expression

Relative deficiency in production of glycoprotein hormone erythropoietin (Epo) is a major cause of renal anemia. This study planned to investigate whether the hypoxia-regulated system of Epo expression, constructed by fusing Epo gene to the chimeric phosphoglycerate kinase (PGK) hypoxia response elements (HRE) in combination with cytomegalovirus immediate-early (CMV IE) basal gene promoter and delivered by plasmid intramuscular injection, might provide a long-term physiologically regulated Epo secretion expression to correct the anemia in adenine-induced uremic rats. Plasmid vectors (pHRE-Epo) were synthesized by fusing human Epo cDNA to the HRE/CMV promoter. Hypoxia-inducible activity of this promoter was evaluated first in vitro and then in vivo in healthy and uremic rats (n = 30 per group). The vectors (pCMV-Epo) in which Epo expression was directed by a constitutive CMV gene promoter served as control. ANOVA and Student's t-test were used to analyze between-group differences. A high-level expression of Epo was induced by hypoxia in vitro and in vivo. Though both pHRE-Epo and pCMV-Epo corrected anemia, the hematocrit of the pCMV-Epo-treated rats exceeded the normal (P < 0.05), but that of the pHRE-Epo-treated rats didn't. Hypoxia-regulated system of Epo gene expression constructed by fusing Epo to the HRE/CMV promoter and delivered by plasmid intramuscular injection may provide a long-term and stable Epo expression and secretion in vivo to correct the anemia in adenine-induced uremic rats.