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To evaluate the correlation of the expression of homeodomain-interacting protein kinase 2 (HIPK2) with human papillomavirus (HPV) infection and apoptosis in cervical cancer.Formalin-fixed, paraffin embedded tissue samples from 50 cervical cancers and 15 normal uterine cervix cases were obtained. Apoptosis was quantified by TdT-mediated dUTP nick end labeling (TUNEL) assay and the expression of HIPK2 as well as HPV by immunohistochemical staining.HIPK2 protein expression was detected in 88.0% (44/50) of cervical cancers and 6.7% (1/15) of normal cervical tissues. HPV was found in 78.0% (39/50) of cervical cancers and 20.0% (3/15) of normal cervical tissue samples. The expression of HIPK2 protein was significantly and positively correlated with HPV presence (r=0.467, P0.01), but negatively with apoptotic index (r=-0.370, P0.05).HIPK2 protein expression is positively correlated with HPV infection, but negatively with apoptotic index in cervical cancers. Therefore, HIPK2 may be involved in the mechanism of apoptosis in cervical cancer and may play an important role in cervical carcinogenesis.

To study the anti-tumor immunotherapeutic effect induced by the suicidalcancer vaccine FC/TK, and to evaluate the safety of this vaccine.The suicidal cancer vaccine, named FC/TK, was prepared by fusion of suicide gene (HSVI,-TK gene) -modified ovarian carcinoma NuTu-19 cells with rat bone marrow-derived dendritic cells (DCs). The morphology of FC/TK was evaluated by scanning electron microscopy. The stimulatory effect of FC/TK on T cells was determined by T cell proliferation assay. In immunotherapeutic studies in vivo, Fischer344 rats were injected subcutaneously with NuTu-19 cells, followed by treatment of FC/TK on days 7 and 14, compared to controls treated with irradiated FC/TK, FC or PBS, respectively. Tumor incidence and volume were measured in 90 days after challenge. To determine the killing effect of FC/TK in vivo, TUNEL assays were applied to detect apoptotic cell death in spleen of vaccinated rats with prodrug ganciclovir administration.FC/TK cells were of irregular shape with surface membrane processes. Compared to the control groups, FC/TK significantly promoted T cell proliferation (P0.01). The rats vaccinated with FC/TK and FC significantly inhibited the tumor growth compared to rats vaccinated with irradiated FC/TK (P0.05) or with PBS ( P0.01). The immunotherapeutic effect induced by FC/TK was similar to that using FC. Fluorescence microscopy showed that fluorescein-stained FC/TK cells migrated into spleen also showed to be TUNEL-positive, suggesting that the FC/TK cells were killed by ganciclovir in vivo.Our data indicate that suicidal cancer vaccine is an effective and safe therapy for ovarian carcinoma and may serve as a broadly applicable approach for other cancer vaccines in the future.

Live tumor vaccines could achieve better immunotherapeutic effects than irradiated tumor vaccines; however, the tumorigenicity is the crucial drawback incurred by the current procedures for vaccine preparation. This study was to explore the application of herpes simplex virus type 1 thymidine kinase/ganciclovir (HSV1-TK/GCV) system as "in vivo death switch" to control the survival status of cancer vaccines under certain circumstances.Suicide gene HSV(1)-TK was transferred into ovarian cancer cell line NuTu-19 with a retrovirus vector, followed by G418 selection to obtain HSV(1)-TK-transfected NuTu-19 cells (NuTu-19/TK). Dendritic cells (DCs) derived from Fischer344 rat bone marrow were fused with NuTu-19/TK cells to construct live tumor vaccine FC/TK. The expression of HSV(1)-TK in FC/TK cells was determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The cytotoxic efficacy of GCV on FC/TK cells was evaluated by XTT assay. The apoptosis of FC/TK cells was analyzed by flow cytometry and Hoechst33258 staining after GCV treatment. Rats were vaccinated with FC/TK cells and divided into 2 groups: GCV group (5 rats) were intraperitoneally treated with GCV for 7 days, control group (5 rats) were treated with normal saline. The tumorigenesis and tumor metastasis in the rats were observed 90 days after inoculation.HSV1-TK was specifically expressed in FC/TK cells. GCV showed in vitro cytotoxicity to FC/TK cells in a dose-dependent manner, and 86.25% of the FC/TK cells were killed by GCV at a concentration of 100 microg/ml; the apoptosis rate of FC/TK cells was over 80%, and apoptotic morphology, including cell shrinkage, chromatin condensation, was observed. In the rat models, the tumor was developed at the injection site in 3 rats of control group, while no tumor was observed in the rats of GCV group.HSV(1)-TK/GCV could act as the "death switch" of tumor vaccines by triggering apoptosis of tumor vaccines both in vitro and in vivo.