[A case of papillary adenocarcinoma of the ovary that responded favorably to irinotecan hydrochloride and cisplatin after the administration of paclitaxel and carboplatin].

Recently, the standard treatment for advanced ovarian cancer has changed from CP therapy (cyclophosphamide, cisplatin (CDDP)) to TJ therapy (paclitaxel (TXL), carboplatin (CBDCA)). Irinotecan (CPT-11) is one of the derivatives of camptotecin and has been reported to have a high efficacy for ovarian cancer. In one case of ovarian cancer, chemotherapy was applied with CBDCA and TXL. However, after 2 months of six courses of the chemotherapy, CA-125 was elevated. The elevation of tumor marker levels in serum without the recurrent focus forced us to treat the patient with CPT-11 and CDDP for the second line chemotherapy. Tumor marker levels improved at the beginning of the therapy. In conclusion, CPT-11 and CDDP was effective against the recurrence of ovarian cancer treated with TJ therapy.

Suicide gene therapy for human uterine adenocarcinoma cells using herpes simplex virus thymidine kinase.

In gene therapy, the herpes simplex virus thymidine kinase (HSV-tk) gene is widely used as a suicide agent. Tumor cells expressing HSV-tk are sensitive to nucleoside analogs such as ganciclovir (GCV). An advantage of this system is the bystander killing effect whereby HSV-tk-positive cells exposed to GCV are lethal to surrounding HSV-tk-negative cells. We transfected the HSV-tk gene into a human cervical adenocarcinoma cell line, BU25TK-, and a human endometrial adenocarcinoma cell line, HHUA, by the Lipofectine method. The sensitivity of HSV-tk-positive cells to GCV and bystander killing effect on HSV-tk-negative cells were examined in vitro. HSV-tk-positive cells were sensitive to GCV at concentrations of 1 to 100 microg/ml in a dose- and time-dependent manner. The growth of HSV-tk-negative cells was inhibited when the population of cultured cells contained more than about 3% HSV-tk-positive cells. Moreover, for BU25TK- cells, HSV-tk-positive cells were injected into SCID mice subcutaneously and the effects of GCV therapy and bystander killing at a daily concentration of 25 mg/kg for 14 days were examined. HSV-tk-positive tumors transduced into SCID mice almost disappeared upon GCV treatment. Furthermore, tumor reduction was observed when mixtures of HSV-tk-negative cells containing more than 20% HSV-tk-positive cells were injected into SCID mice. In conclusion, the HSV-tk/GCV system might be applied to both cervical and endometrial adenocarcinoma.

cAMP stimulates the bystander effect in suicide gene therapy of human choriocarcinoma.

In gene therapy, tumor cells expressing herpes simplex virus thymidine kinase (HSV-tk) are sensitive to ganciclovir (GCV) and HSV-tk positive cells exposed to GCV are lethal to adjacent HSV-tk negative cells. This phenomenon has been called the bystander effect, and the gap junction is thought to mediate it. In this study, sensitivity to GCV and bystander effect in a human choriocarcinoma cell line, BeWo, transfected with HSV-tk were investigated. Furthermore, the effect of 8-bromo-cAMP on bystander effect and connexin40 gene transcription were examined. HSV-tk positive cells were sensitive to GCV at the concentration of 10 micrograms/ml in a time-dependent manner. The growth of HSV-tk negative cells was inhibited when the population of cultured cells contained more than 10% HSV-tk positive cells and 8-bromo-cAMP enhanced bystander effect. 8-bromo- cAMP increased connexin40 mRNA expression and gap junctional intercellular communication.