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ABSTRACT: Uterine leiomyomas are the most common gynecological benign tumors and greatly affect reproductive health and wellbeing. Metformin is the most widely used antidiabetic drug in the world, and there is increasing evidence of a potential efficacy of this agent as an anticancer drug. In order to understand metformin's anti-tumorigenic potential better, in this study, we investigated the inhibitory effect of metformin and expression of key targets of metformin cell signaling in leiomyoma cells. Cell proliferation was assessed after exposure to metformin. Apoptosis was assessed by western blotting for cleaved-PARP and TUNEL staining. The expressions of phosphorylated AMPK and phosphorylated S6 were determined by western blotting. Metformin potently inhibited ELT-3 cell proliferation in a dose-dependent manner. Western blotting analysis demonstrated that metformin induced phosphorylation of AMPK and the inhibitory effect was attenuated with AMPK inhibitor, compound C. In parallel, treatment with metformin decreased phosphorylation of S6 protein. These experimental findings show that metformin is a potent inhibitor of cell proliferation in leiomyoma cells. This effect is mediated by AMPK activation and subsequent inhibition of the mTOR pathway. Thus, this study provides a possible mechanism of the action of metformin in the inhibition of leiomyoma cell growth.
Gynecological Endocrinology 07/2012; · 1.58 Impact Factor
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ABSTRACT: To investigate the diagnostic significance of Golgi membrane protein 1 (GOLM1) expression in prostate cancer.
The localization of GOLM1 in prostate cancer cells was detected by immunofluorescence. The GOLM1 expression in prostate cancer cells at the mRNA and protein level was determined by quantitative real-time polymerase chain reaction and Western blot analysis, respectively. A prostate cancer tissue microarray was used to analyze GOLM1 protein expression by immunohistochemistry.
The immunofluorescence results demonstrated that GOLM1 was located at the cis-Golgi in the DU145 cells. GOLM1 transcripts and protein were overexpressed in a wide variety of prostate cancer cell lines (DU145, 22RV1, PC-3, and LNCaP). Tissue microarray immunohistochemistry demonstrated that GOLM1 protein staining was occasionally found in the normal prostate gland and benign prostatic hyperplasia, whereas that in prostate cancer was predominantly observed in the cytoplasm of tumor cells. GOLM1 protein was strongly expressed in prostate cancer tissues, and there was a significant difference compared with the normal prostate and benign prostatic hyperplasia cases (P < .05). There were no significant differences between GOLM1 overexpression and pathologic variables of prostate cancer, including histologic grade and pathologic stage (P > .05).
Our results suggest that GOLM1 protein is significantly expressed in prostate cancer in comparison with the normal prostate gland and benign prostatic hyperplasia. These findings may suggest that GOLM1 is useful in the diagnosis or therapy of prostate cancer. However, GOLM1 overexpression is not associated with disease stage and grade.
Urology 07/2012; 80(4):952.e1-7. · 2.43 Impact Factor
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ABSTRACT: HS-1-associated protein X-1 (Hax-1), is a multifunctional protein that has sequence homology to Bcl-2 family members. HAX-1 knockout animals reveal that it plays an essential protective role in the central nervous system against various stresses. Homozygous mutations in the HAX-1 gene are associated with autosomal recessive forms of severe congenital neutropenia along with neurological symptoms. The protein level of Hax-1 has been shown to be regulated by cellular protease cleavage or by transcriptional suppression upon stimulation.
Here, we report a novel post-translational mechanism for regulation of Hax-1 levels in mammalian cells. We identified that PEST sequence, a sequence rich in proline, glutamic acid, serine and threonine, is responsible for its poly-ubiquitination and rapid degradation. Hax-1 is conjugated by K48-linked ubiquitin chains and undergoes a fast turnover by the proteasome system. A deletion mutant of Hax-1 that lacks the PEST sequence is more resistant to the proteasomal degradation and exerts more protective effects against apoptotic stimuli than wild type Hax-1.
Our data indicate that Hax-1 is a short-lived protein and that its PEST sequence dependent fast degradation by the proteasome may contribute to the rapid cellular responses upon different stimulations.
BMC Cell Biology 07/2012; 13:20. · 2.59 Impact Factor
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ABSTRACT: The finite element model of the intact lumbar spine (L1-L5) was set up to study the biomechanical changes of three different pairs of the lumbar laminectomy. The three-dimensional finite elements model of L1-L5 vertebrae structure was constructed by the combination of self-compiled software and Hyper Mesh. The finite element model was compared with the experimental data in vitro. The finite element model was modified of stenosis at L3-L4 and L4-L5 with the same boundary conditions and physical loads to study the motion and loading in the annulus changes at the surgical site as a result of surgical alteration. The study suggested that the removal of posterior lumbar spinal elements for the treatment of stenosis at L3-L4 and L4-L5 produced a graded increase in motion at the surgical site, with the greatest changes occurring in flexion-extension and axial rotation and that during lateral bending the amount of resection was only slightly affected. The data showed that for flexion-extension and axial rotation the increases in motion were correlated to the extent of posterior element removal. It is necessary to retain the greatest degree of posterior lumbar structures in thorough decompression, which can further reduce the postoperative intervertebral disc, facet degeneration.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 06/2012; 29(3):465-9.
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ABSTRACT: The aim of the study was to investigate the photodynamic effect of the novel photosensitizer chlorophyllin e4 against human bladder cancer cells. T24 and 5637 bladder cancer cell lines were incubated with chlorophyllin e4 and irradiated with a 650-nm laser light. The controls included cells treated with chlorophyllin e4 but without light as well as cells exposed to laser light without chlorophyllin e4. Photocytotoxicity was monitored with MTT assay and apoptosis was measured by flow cytometry. In addition, confocal laser scanning microscopy was used to assess the subcellular localization of chlorophyllin e4. Chlorophyllin e4 exhibited significant photocytotoxicity in both T24 and 5637 cells, which resulted in a maximum of 82.43 and 85.06% cell death, respectively. Treatment with chlorophyllin e4 or laser light alone did not induce cytotoxicity. In addition, chlorophyllin e4-mediated PDT induced a significantly higher percentage of apoptosis in T24 and 5637 cells compared to the control groups (p<0.01). Moreover, confocal laser scanning microscopy revealed that chlorophyllin e4 co-localized with mitochondria in both cell lines. In conclusion, the remarkable photocytotoxicity, natural abundance and inexpensive composition of chlorophyllin e4 suggest that this compound may be a novel, effective photosensitizer for the treatment of human superficial bladder cancer.
Oncology Reports 05/2012; 27(5):1455-60. · 1.84 Impact Factor
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ABSTRACT: Inflammation in Parkinson's disease is closely associated with disease pathogenesis. Mutations in Omi, which encodes the protease Omi, are linked to neurodegeneration and Parkinson's disease in humans and in mouse models. The severe neurodegeneration and neuroinflammation that occur in mnd2 (motor neuron degeneration 2) mice result from loss of the protease activity of Omi by the point mutation S276C; however, the substrates of Omi that induce neurodegeneration are unknown. We showed that Omi was required for the production of inflammatory molecules by microglia, which are the resident macrophages in the central nervous system. Omi suppressed the activation of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase 1 and 2 (ERK1/2) by cleaving the upstream kinase MEK1 (mitogen-activated or extracellular signal-regulated protein kinase kinase 1). Knockdown of Omi in microglial cell lines led to activation of ERK1/2 and resulted in degradation of IκBα [α inhibitor of nuclear factor κB (NF-κB)], resulting in NF-κB activation and the expression of genes encoding inflammatory molecules, such as tumor necrosis factor-α and inducible nitric oxide synthase. The production of inflammatory molecules induced by the knockdown of Omi was blocked by the MEK1-specific inhibitor U0126. Furthermore, expression of the protease-deficient S276C Omi mutant in a microglial cell line had no effect on MEK1 cleavage or ERK1/2 activation. In the brains of mnd2 mice, we observed increased transcription of several genes encoding inflammatory molecules, as well as activation of astrocytes and microglia. Therefore, our study demonstrates that Omi is an intrinsic cellular factor that inhibits neuroinflammation.
Science Signaling 01/2012; 5(238):ra61. · 7.50 Impact Factor
