Suppression of human MDA-MB-435S tumor by U6 promoter-driven short hairpin RNAs targeting focal adhesion kinase

SurvivinT34A increases the therapeutic efficacy of arsenic trioxide in mouse hepatocellular carcinoma models

Arsenic trioxide (ATO) has demonstrated clinical efficacy in acute promyelocytic leukemia (APL) and in vitro activity in various solid tumors. As2O3 as single agent exhibits poor efficacy for treatment of hepatocellular carcinoma (HCC) in phase II trial, suggesting that new modalities of treatment with enhanced therapeutic effect and alleviated toxicity are needed for application of As2O3 on patients with HCC. Survivin is the strongest inhibitor of apoptosis protein over-expressed in tumors, which has been proposed as an attractive target for new anticancer interventions. Disruption of survivin by the plasmid encoding the phosphorylation-defective mouse survivin threonine 34→alanine mutant (Msurvivin T34A plasmid) has proved a promising strategy for suppressing a variety of murine cancer. In the present study, we attempted to test Msurvivin T34A and arsenic trioxide (ATO) on a cell line and mice bearing subcutaneous tumors, with regard to their effects and mechanisms. We observed that the co-treatment with surivinT34A and ATO significantly enhanced the antitumor activity by induction of apoptosis in Hepa1-6 tumor cells in vitro, compared with control groups. The synergistic apoptosis-inducing effect of combination of these two drugs resulted in elevation of reactive oxygen species (ROS) level which could be antagonized by the antioxidant N-acetyl-l-cysteine. The combination treatment induced ROS-dependent collapse of the mitochondrial membrane potential. Moreover, the tumor growth in vivo was also remarkably inhibited by combination of surivinT34A and ATO when compared with control groups. Our findings demonstrate that the combination of surivinT34A and ATO exerted synergistic antitumor effects, providing a new perspective for clinical treatment of HCC.

The effects of focal adhesion kinase on the motility, proliferation and apoptosis of Caco2 and SMMC-7721 cells

Focal adhesion kinase (FAK) plays important roles in cancer development. However, the significance of FAK expression in colorectal carcinoma and hepatocellular carcinoma has not been clarified. This study aims to explore the roles FAK played in the progression of colorectal carcinoma and hepatocellular carcinoma. RNAi method was used to inhibit the expression of FAK in Caco2 and SMMC-7721 cells. Reverse transcriptase polymerase chain reaction analysis and Western blot analysis were used to examine mRNA and protein expression of FAK. Then, the proliferation, motility and apoptosis of both types of cells were detected using MTT assay, wound healing/transwell assay and nuclear staining assay. The microstructure changes (F-actin, β-tubulin and lamin B1) of SMMC-7721 cells were visualized by immunofluorescence. FAK was overexpressed in both cell lines and down-regulation of FAK resulted in suppression of cell proliferation, inhibition of cell migration and invasion. The apoptosis of cells was increased significantly following the FAK expression inhibition. Moreover, actin polymerization, β-tubulin and lamin B1 expression of cells were significantly decreased. The results highlight the role of FAK in the progression of cancers. These findings suggest FAK serve as a potential therapeutic target for cancer therapy.

Involvement of focal adhesion kinase in cellular proliferation, apoptosis and prognosis of laryngeal squamous cell carcinoma

OBJECTIVE

This study aimed to investigate the relationship between focal adhesion kinase expression and clinicopathological factors, cell apoptosis and proliferation, and overall survival, in laryngeal squamous cell carcinoma.

METHODS

Immunohistochemical staining was used to detect the expression of focal adhesion kinase and proliferating cell nuclear antigen in tissue samples. Apoptotic cells were assessed using the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling ('TUNEL') method.

RESULTS

The proportion of focal adhesion kinase expression was 73.26 per cent in tumour tissues, significantly greater than in normal tissues (p < 0.05), and was significantly related to laryngeal cancer clinical stage, lymph node metastasis and overall survival (p < 0.05). In the tumour cases assessed, up-regulation of focal adhesion kinase expression was significantly associated with decreased cell apoptosis and increased proliferation (p < 0.05).

CONCLUSION

These findings suggest that focal adhesion kinase may affect laryngeal squamous cell carcinoma progression through regulation of cell apoptosis and proliferation. Focal adhesion kinase expression is a major prognostic factor in laryngeal cancer patients.