Metastasis is the most lethal attribute of human malignancy. High-level expression of survivin is involved in both carcinogenesis and angiogenesis in cancer. Previous studies indicate that a mutation of the threonine residue at position 34 (Thr34Ala) of survivin generates a dominant-negative mutant that induces apoptosis, inhibits angiogenesis, and suppresses highly metastatic breast carcinoma in mouse models. We investigated the efficacy of gene therapy with a survivin dominant-negative mutant and possible factors related to lymph node metastasis. The metastasis rate was compared between each group in order to find a survivin-targeted therapy against lymphangiogenesis in its earliest stages. We established lymph node metastasis models and treated animals with H22 tumors with Lip-mSurvivinT34A (Lip-mS), Lip-plasmid (Lip-P), or normal saline (NS). Eight days after the last dose, five randomly chosen mice from each group were sacrificed. We detected the apoptotic index, microvessel density (MVD), lymphatic microvessel density (LMVD), and the expression of VEGF-D with immunohistochemistry. After the remaining animals were sacrificed, we compared the tumor-infiltrated lymph nodes in each group. Administration of mSurvivinT34A plasmid complexed with cationic liposome (DOTAP/chol) resulted in the efficacious inhibition of tumor growth and lymph node metastasis within the mouse H22 tumor model. These responses were associated with tumor cell apoptosis, and angiogenesis and lymphangiogenesis inhibition. Our results suggested that Lip-mSurvivinT34A induced apoptosis and inhibited tumor angiogenesis and lymphangiogenesis, thus suppressing tumor growth and lymphatic metastasis. The mSurvivinT34A survivin mutant is a promising strategy of gene therapy to inhibit lymphatic metastasis.

Purpose Patients with localized prostate cancer can usually achieve initial response to conventional treatment. However, most of them will inevitably progress to advanced disease stage. There is a clear need to develop innovative and effective therapeutics for prostate cancer. Mouse survivin T34A (mS-T34A) is a phosphorylation-defective Thr34 → Ala dominant negative mutant, which represents a potential promising target for cancer gene therapy. This study was designed to determine whether mS-T34A plasmid encapsuled by DOTAP-chol liposome (Lip-mS) has the anti-tumor activity against prostate cancer, if so, to further investigate the possible mechanisms. Methods In vitro, TRAMP-C1 cells were transfected with Lip-mS and examined for apoptosis by PI staining and flow cytometric analysis. In vivo, subcutaneous prostate cancer models were established in C57BL/6 mice, which were randomly assigned into three groups to receive i.v. administrations of Lip-mS, pVITRO2-null plasmid complexed with DOTAP-chol liposome (Lip-null) or normal saline every 2 days for eight doses. Tumor volume was measured. Tumor tissues were inspected for apoptosis by TUNEL assay. Microvessel density (MVD) was determined by CD31 immunohistochemistry. Alginate-encapsulated tumor cell test was conducted to evaluate the treatment effect on angiogenesis. Results Administration of Lip-mS resulted in significant inhibition in the growth of mouse TRAMP-C1 tumors. The anti-tumor response was associated with increased tumor cell apoptosis and decreased microvessel density. Conclusions The present study may be of importance in the exploration of the potential application of Lip-mS in the treatment of a broad spectrum of tumors.

OBJECTIVETo investigate the effect of Survivin-T34A mutant on murine prostate cancer and its apoptosis-inducing efficacy in vivo and in vitro.METHODSIn vitro, prostate cancer cells TRAMP-C1 were transfected with Survivin-T34A plasmid encapsulated by cationic liposome. The apoptosis of TRAMP-C1 was evaluated with flow cytometry. C57BL/6 mice model with TRAMP-C1 prostate cancer was established. Twenty four male mice with TRAMP-C1 prostate cancers were divided randomly into three groups, which were intravenously injected with normal saline, empty vector PORF-9-null encapsulated by cationic liposome and Survivin-T34A plasmid encapsulated by cationic liposome respectively twice a week for eight doses. The size of tumors was measured and the tumor sections of each group were stained with TUNEL reagent for apoptosis detection.RESULTSAn apoptotic index of 46% of TRAMP-C1 transfected with Survivin-T34A plasmid encapsulated by cationic liposome was observed. The tumor volume of Survivin-T34A group of C57BL/6 mice with TRAMP-C1 prostate cancer was far smaller than those in the control groups (P < 0.05) and the tumors treated with Survivin-T34A showed significant increase of apoptosis compared with those of control groups (P < 0.05).CONCLUSIONSurvivin-T34A mutant efficiently inhibits the growth of prostate cancer, which is based on the mechanism of Survivin-T34A mutant inducing apoptosis of tumor cells.

Anti-apoptosis plays an important role in tumour formation and development. Survivin is a member of the inhibitor of apoptosis (IAP) family, which is a target for anti-cancer drug exploitation was replaced as development. We investigated the role of the homo dominant-negative mutant Survivin-T34A in suppressing human lung adenocarcinomas (A549). The anti-tumour activity of HSurvivinT34A plasmid was evaluated in the A549 cell line and nude mice bearing A549 subcutaneous tumours. Low-dose systemic administration was continuously used. The HSurvivinT34A plasmid (5 µg/one) complexed with a cationic liposome (DOTAP/Chol) significantly inhibited tumour growth in our model. We observed microvessel density degradation by CD31 immunohistochemistry and apoptotic cell increase by TUNEL assay, PI staining and flow cytometric analysis in the treated group. The present findings suggest that the HSurvivinT34A plasmid complexed with a cationic liposome may provide an effective approach to inhibit the growth of human lung adenocarcinomas in vitro and in vivo.