Isoliquiritigenin(ISL), a calchone flavonoid, has cancer-preventing properties and is often used in Chinese medicine. In the present study, the authors use ISL to determine its effect on cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. Cell viability and cell proliferation assays were conducted. Flow cytometry, annexin V apoptosis assay, and DNA fragmentation assay were performed to determine the effect of ISL on cell cycle and apoptosis. The expression of cell cycle regulatory-related proteins was evaluated by Western blot. The cell viability and proliferation of uterine leiomyoma cells were significantly reduced by ISL treatment in a dose-dependent manner. Flow cytometry results showed that ISL induced subG1 and G2/M arrest. DNA fragmentation assay and annexin V apoptosis assays revealed apoptosis induction. ISL-induced growth inhibition in uterine leiomyoma cells was associated with increased p21(Cip1/) Waf1 expression in a p53-dependent manner. Activation of caspase-3 and downregulation of Bcl-2, cdk 2/4, and E2F, with a concomitant increase in dephosphorylation of Rb and poly-ADP-ribose polymerase cleavage, were observed. This study demonstrates that ISL inhibits cell proliferation by initiating apoptosis in human uterine leiomyoma cells coupled with increased cell cycle arrest. These results indicate that ISL could prove to be a promising chemopreventive and therapeutic agent against human uterine leiomyoma.

No abstract

The nuclear receptors PPARs (peroxisome proliferator-activated receptors) are transcription factors that play important roles in multiple disease conditions. The activation of PPARs by specific ligands is associated with growth suppression of several different types of human cancer, but the molecular mechanism responsible for this growth suppressive effect remains elusive. The aim of this study was to determine the distribution of PPARgamma protein/mRNA expression in uterine leiomyomas and to identify the PPARgamma induced signaling pathways responsible for the growth inhibition induced by treatment with ciglitizone, a synthetic ligand of PPARgamma, in view of identifying targets that could possibly affect the viability and proliferation of uterine leiomyoma cells. Dose-response studies on proliferation found that uterine leiomyoma was more sensitive to inhibition by ciglitizone treatments than normal myometrium. We also found that ciglitizone significantly stimulated gene expression driven by a PPAR-responsive element in cultured leiomyoma cells and reduced the survival of leiomyoma cells relative to the control cells. The reduced survival of ciglitizone treated leiomyoma cells resulted from a mechanism that involved the Fas receptor-mediated apoptosis signaling cascade. These results suggest that uterine leiomyomas growth and differentiation might be modulated through PPARgamma receptors and that PPARgamma ligands may be of potential use for uterine leiomyoma treatment.

Medulloblastomas occurring in children represent a histological spectrum of varying anaplasia and nodularity. In order to determine whether immunohistochemical markers might be useful parameters in subclassifying these tumors, 17 pediatric medulloblastomas, including nine diffuse/non-anaplastic, four diffuse/anaplastic, three nodular/non-anaplastic and one nodular/anaplastic subtypes, were studied. In the present report, we investigate the expression of neural cell adhesion molecule (NCAM), nerve growth factor receptor (NGFR), neurofilament (NF), synaptophysin (SYN), glial fibrillary acidic protein (GFAP), S100, Bcl-2, and Ki-67 by using the immunohistochemistry against specific antibodies. This study showed that NGFR, NF, GFAP and S100 were not detected in anaplastic subtypes of medulloblastomas (0/5), while non-anaplastic subtypes were mainly expressed within the nodules. All 17 tumors were reactive for NCAM, SYN and Bcl-2. In addition, Ki-67 labeling indices for anaplastic subtypes (39.0 +/- 7.42%) were significantly higher than that of non-anaplastic medulloblastomas (11.4 +/- 8.04%; P < 0.0001). These results suggest that immunohistochemical markers are a useful adjunct in characterizing subtypes of pediatric medulloblastomas.

Observations from the authors' laboratory suggest a physiological role for increased cyclin G1 protein levels in human uterine leiomyoma. The hypothesis of the present study is that the strategic modulation of cyclin G1 by antisense technology will inhibit the survival of in vitro-grown uterine leiomyoma cells. Cultured uterine leiomyoma cells were transfected with cyclin G1 ribbon-type antisense oligonucleotide (cyclin G1 RiAS) to effectively reduce cyclin G1 expression. Cell viability, in situ terminal deoxyuridine nick end-labeling (TUNEL) assay, flow cytometry, DNA fragmentation, and expression of cell cycle regulatory-related proteins were evaluated by Western blot. Antisense oligonucleotides compromised uterine leiomyoma cell viability and inducted apoptosis in a caspase-independent mechanism. In situ TUNEL and DNA fragmentation revealed apoptosis induction, and fluorescent-activated cell sorting analysis showed increased sub-G1-phase cells. Furthermore, abrogation of cyclin G1 enhanced p53 accumulation, phosphorylation of p53 at Ser-15 residue, and increased expression of cyclin-dependent kinase inhibitors p21 and p27. These data imply that cyclin G1 expression is associated with growth promotion and the potential utility and novelty of using ribbon-type antisense oligonucleotides as a gene therapy strategy to treat human uterine leiomyoma.