Subcellular localization of MCM2 correlates with the prognosis of ovarian clear cell carcinoma.

Highly malignant tumors overexpress the minichromosome maintenance 2 (MCM2) protein in the nucleus, which is associated with advanced tumor grade, advanced stage, and poor prognosis. In this study, we showed that MCM2 is highly expressed in clinical samples of ovarian clear cell carcinoma. Although MCM2 expression was mainly localized to the nuclei as in other cancers, a few cases exhibited cytoplasmic localization of MCM2. Surprisingly, tumor samples with cytoplasmic MCM2 demonstrated excellent prognosis, showing 100% survival during the observation period of more than 200 months. However, cases with nuclear expression of MCM2 exhibited approximately 78% 5-year-survival rate. In a previous study, we showed that Friend leukemia virus (FLV) envelope protein gp70 bound to MCM2, impaired its nuclear translocation, and enhanced DNA damage-induced apoptosis in FLV-infected hematopoietic cells with high levels of MCM2. As expected, clear cell carcinoma cells with cytoplasmic expression of MCM2 exhibited significantly higher apoptotic cell ratio than that of cells with nuclear MCM2 expression. In vitro experiments using ovarian cancer cells with cytoplasmic expression of MCM2 demonstrated that transfection of MCM2-ΔN enhanced DNA damage-induced apoptosis. Therefore, cytoplasmic localization of MCM2 significantly correlated with increased apoptosis in clear cell carcinoma cells, resulting in improved prognosis.

Preparation of (103)Pd brachytherapy seeds by electroless plating of (103)Pd onto carbon bars.

A method for preparing (103)Pd brachytherapy seeds is reported. The key of the method was to deposit (103)Pd onto carbon bars by electroless plating so as to prepare source cores. After each carbon bar with (103)Pd was sealed in a titanium capsule, the (103)Pd seeds were fabricated. This paper provides valuable experiences and data for the preparation of (103)Pd brachytherapy seeds.

[Therapeutic effect of 125I-103Pd hybrid radioactive seeds on pulmonary carcinomas in BALB/c-nu mice].

OBJECTIVE: To prepared (125)I-(103)Pd hybrid radioactive seeds and to explore their therapeutic effect on pulmonary carcinomas. METHODS: The (125)I-(103)Pd hybrid radioactive seeds were prepared by a chemical method of step-by-step coat plating. Pulmonary adenocarcinoma of GLC-82 cells and pulmonary large cell carcinoma of H460 cells were cultured in vitro and then were exposed directly to (125)I, (103)Pd and (125)I-(103)Pd seeds for 48 hours to observe the killing effects of radiation. GLC-82 and H460 tumor models were established and 20 mice chosen randomly for each model. For each tumor model, there were 4 groups (n = 5 each). Then (125)I-(103)Pd, (125)I, (103)Pd and nonradioactive seeds were implanted into the tumors. Tumor sizes and weights of mice were measured and recorded every 5 days for a 2-month observation. RESULTS: The (125)I-(103)Pd hybrid radioactive seeds were prepared successfully. After a 48-hour radiation from radioactive seeds, the GLC-82 cells within one particulate around (125)I, (103)Pd or (125)I-(103)Pd seeds were inhibited so as to become swollen and transfiguring. The H460 cells around (125)I seeds showed no obvious abnormality while those within one particulate around (103)Pd or (125)I-(103)Pd seeds were much fewer. No mouse died during the observation period. The radioactive seeds could inhibit the tumors. The radiotherapeutic effects were similar in two tumor modes: (125)I-(103)Pd seeds > (103)Pd seeds ≈ (125)I seeds > non-radioactive seeds. H460 tumors grew much faster than GLC-82 tumors. Meanwhile the seeds with the same nuclide were much more effective for GLC-82 tumors than for H460 tumors. CONCLUSION: The (125)I-(103)Pd hybrid radioactive seeds are clinically applicable due to their effective inhibitions of tumor growth.