Establishment of three cisplatin-resistant endometrial cancer cell lines using two methods of cisplatin exposure.

Using the endometrial cancer cell line EI established in our department, we attempted to establish cisplatin (CDDP)-resistant cell lines by incremental exposure and high concentration exposure methods. Three CDDP-resistant cell lines were isolated, which could be distinguished by morphological differences. 1. Upon acquiring CDDP resistance, the cells tended to become small and grow in a floating state. This tendency was especially marked when using incremental exposure method. Using the incremental exposure method, a cell line obtained by isolating and culturing only adherent cells was designated EICR-Ia, and a cell line established by culturing only floating cells was designated EICR-If. A cell line obtained by the high concentration exposure method was designated EICR-II. 2. Upon acquiring CDDP resistance, tumor markers such as TPA and LDH increased, while proliferative capability of the cells was lowered. 3. The invasion capability was diminished in EICR-If cells, but was increased in EICR-Ia and EICR-II cells. 4. Following exposure to CDDP, the intracellular platinum concentrations were markedly elevated in EI and EICR-If cells, whereas the increase was mild in EICR-Ia and EICR-II cells and the concentration was lower than that in parent EI cells. 5. Studies of drug resistance gene expression revealed increased expression of MDR1, GSTπ, and Topo-II in EICR-If cells; increased expression of GSTπ in EICR-II cells; but no expression of any of the genes in EICR-Ia cells. 6. Analyses of cancer- and apoptosis-related genes showed increased expressions of Bcl-2, c-Myc, p53, and ICE in EICR-If cells. 7. Upon acquiring CDDP resistance, sensitivity to mitomycin and adriamycin decreased, but sensitivity to etoposide and 5-fluorouracil increased. The findings indicate that the mechanisms of CDDP resistance are different in the three cell lines.

Induction of apoptosis in human choriocarcinoma cell lines by treatment with 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone (vesnarinone).

Induction of apoptosis is an attractive strategy in cancer therapy but it clinical practice is not yet sufficient in choriocarcinoma. The quinolinone derivative, vesnarinone, is a novel inotropic agent used for treating congestive heart failure and may also have a potential anticancer activity. It induces apoptosis and differentiation in some tumor cell lines. We examined the antitumor effect of vesnarinone in eight cell lines established from human choriocarcinoma and hydatidiform mole using MTT assay and also analyzed the nuclear fragmentation of tumor cells by DNA electrophoresis assay. Vesnarinone inhibited the proliferation of choriocarcinoma cell lines in a dose-dependent manner and induced DNA fragmentation in cells. However, the BM cell line prepared by subcultivation from hydatidiform mole showed no growth suppression or DNA fragmentation in response to vesnarinone. On the other hand, PCR-SSCP analysis and direct DNA sequencing have shown that a human choriocarcinoma cell line, SCH, has a mutant p53 gene at codon 249. When SCH cells were treated with vesnarinone cellular proliferation was significantly inhibited. Vesnarinone suppressed the proliferation of all choriocarcinoma cell lines and induced apoptosis, regardless of the existence of p53 mutation. In addition, it has been found by RT-PCR that expression of c-Myc mRNA is upregulated by treating choriocarcinoma cells with vesnarinone. The finding suggests that vesnarinone might induce expression of c-Myc gene in choriocarcinoma cells, the product of which may be associated with the inhibition of cell growth and induce apoptosis. These results suggest that vesnarinone is a useful reagent for the treatment of choriocarcinoma.

Dysgerminoma in a patient with a tumor of the neck. Empiric treatment of stage IV dysgerminoma.

The evolution of therapy for malignant ovarian germ cell tumors is one of the true success stories in oncology. Treatment outcome has improved greatly thanks to cisplatin-based combination chemotherapy. According to the well-established treatment guidelines for advanced cases, we treated a case of stage IV undifferentiated germ cell tumor in which we were able to preserve the patient's fertility. We concluded that the PEP regimen is an effective treatment for the patient with metastatic germ cell tumor.