RNAi-induced K-Ras gene silencing suppresses growth of EC9706 cells and enhances chemotherapy sensitivity of esophageal cancer

Biodegradable nanoparticles as siRNA carriers for in vivo gene silencing and pancreatic cancer therapy

Biodegradable charged polyester-based vectors (BCPVs) were utilized for efficiently delivering mutatedK-Ras-targeting siRNA and successfully inhibiting tumor growth in a pancreatic xenograft modelin vivo.

MiR-622 functions as a tumor suppressor and directly targets E2F1 in human esophageal squamous cell carcinoma

PURPOSE

MicroRNA-622 has been proven down-regulated in many human malignancies and correlated with tumor progression. However, its role in esophageal squamous cell carcinoma (ESCC) is still unclear. The aim of this study was to explore the expression and function of miR-622 in ESCC.

METHODS

Using quantitative RT-PCR, we detected miR-622 expression in ESCC cell lines and primary tumor tissues. The association of miR-622 expression with clinicopathological factors and prognosis was also analyzed. Then, the effects of miR-622 on the biological behavior of ESCC cells were investigated. At last, the potential regulatory function of miR-622 on E2F1 expression was confirmed.

RESULTS

miR-622 was found to be down-regulated in ESCC tissues and cell lines. Decreased miR-622 expression was closely correlated with aggressive clinicopathological features and poor overall survival. Multivariate regression analysis corroborated that low level of miR-622 expression was an independent unfavourable prognostic factor for patients with ESCC. Up-regulation of miR-622 could significantly reduce ESCC cell proliferation, enhance cell apoptosis, and impair cell invasion and migration in vitro, while down-regulation of miR-622 showed opposite effects. Further, E2F1 was confirmed as a direct target of miR-622 by using Luciferase Reporter Assay.

CONCLUSIONS

These findings indicate that miR-622 may act as a tumor suppressor in ESCC and would serve as a potential therapy target for this disease.

HMGCR is necessary for the tumorigenecity of esophageal squamous cell carcinoma and is regulated by Myc

Hydroxymethylglutaryl coenzyme A reductase (HMGCR), the rate-limiting enzyme of mevalonate pathway, has been involved in the tumorigenesis of several tumor types. Our previous study has showed that statin, the inhibitor of HMGCR, inhibited the tumorigenecity of esophageal squamous cell carcinoma (ESCC) in vitro and in vivo. However, the function of HMGCR in the carcinogenesis of ESCC cells remains unknown. In this study, we have observed the up-regulation of HMGCR in ESCC tissues compared with the paired normal tissues. Over-expression of HMGCR in ESCC cells promoted cell growth and migration, while knockdown of the expression of HMGCR inhibited the growth, migration and colony formation of ESCC cells in vitro and in vivo. Furthermore, we found that oncogene Myc positively regulated the expression of HMGCR. Taken together, our study revealed the pivotal function of HMGCR and mevalonate pathway in the progression of ESCC and supported the clinical application of statin.