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Human embryonic stem (hES) cells can be guided to differentiate into ventral midbrain-type neural precursor (NP) cells that proliferate in vitro by specific mitogens. We investigated the potential of these NP cells derived from hES cells (hES-NP) for the large-scale generation of human dopamine (DA) neurons for functional analyses and therapeutic applications. To address this, hES-NP cells were expanded in vitro for 1.5 months with six passages, and their proliferation and differentiation properties determined over the NP passages. Interestingly, the total hES-NP cell number was increased by > 2 × 104-folds over the in vitro period without alteration of phenotypic gene expression. They also sustained their differentiation capacity toward neuronal cells, exhibiting in vitro pre-synaptic DA neuronal functionality. Furthermore, the hES-NP cells can be cryopreserved without losing their proliferative and developmental potential. Upon transplantation into a Parkinson’s disease rat model, the multi-passaged hES-NP cells survived, integrated into the host striatum, and differentiated toward the neuronal cells expressing DA phenotypes. A significant reduction in the amphetamine-induced rotation score of Parkinson’s disease rats was observed by the cell transplantation. Taken together, these findings indicate that hES-NP cell expansion is exploitable for a large-scale generation of experimental and transplantable DA neurons of human-origin. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to investigate the mechanisms involved in the antiproliferative and apoptotic effects of MCS-C2, a novel analog of the pyrrolo[2,3- d]pyrimidine nucleoside toyocamycin and sangivamycin, in human prostate cancer LNCaP cells. MCS-C2, a selective inhibitor of cyclin-dependent kinase, was found to inhibit cell growth in a time- and dose-dependent manner, and inhibit cell cycle progression by inducing the arrest of the G1 phase and apoptosis in LNCaP cells. When treated with 3 µM MCS-C2, inhibited proliferation associated with apoptotic induction was found in the LNCaP cells in a concentration and time-dependent manner, and nuclear DAPI staining revealed the typical nuclear features of apoptosis. Furthermore, MCS-C2 induced cell cycle arrest in the G1 phase through the upregulated phosphorylation of the p53 protein at Ser-15 and activation of its downstream target gene p21WAF1/CIP1. Accordingly, these results suggest that MCS-C2 inhibits the proliferation of LNCaP cells by way of G1-phase arrest and apoptosis in association with the regulation of multiple molecules in the cell cycle progression. ( Cancer Sci 2006; 97: 430 –436) [ABSTRACT FROM AUTHOR]

Cerebellum plays an important role in integration of sensory perception and motor coordination. Although it constitutes only 10 % of total brain volume, cerebellum contains nearly 50 % of all neurons in the brain. To investigate the roles of cells in cerebellum during physiological and pathological processes in a model system in vitro, we established and characterized a cerebellar cell line (CRBL) isolated from mice lacking expression of a gene involved in cell cycle. Unlike the culture of cerebellar cells from wild type animals that undergoes senescence, the CRBL cells immortally survived in vitro. They were resistant to G418 treatments due to the expression of a neo-cassette inserted in the middle of the target gene open reading frame. Their growth was greatly influenced by the different levels of serum in the media. Karyotype analysis of the cell line revealed hypotetraploidy. The changes in the numbers of chromosomes varied. The CRBL cells were morphologically heterogeneous displaying the cells of variable sizes and shapes. By flow cytometry and Western blotting analysis we found CRBL cells express a neuronal cell marker protein beta-III tubulin, a glial cell marker protein glial fibrillary acidic protein, and cellular prion protein. This newly established cell line will be a valuable tool to understand cerebellar functions and neuropathological mechanisms in cerebellum. [ABSTRACT FROM AUTHOR]