• Molecules and Cells
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• v.41 no.2
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• pp.119-126
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• 2018

microRNA (miR)-612 shows anticancer activity in several types of cancers, yet its function in melanoma is still unclear. This study was undertaken to investigate the expression of miR-612 and its biological relevance in melanoma cell growth, invasion, and tumorigenesis. The expression and prognostic significance of miR-612 in melanoma were examined. The effects of miR-612 overexpression on cell proliferation, colony formation, tumorigenesis, and invasion were determined. Rescue experiments were conducted to identify the functional target gene(s) of miR-612. miR-612 was significantly downregulated in melanoma tissues compared to adjacent normal tissues. Low miR-612 expression was significantly associated with melanoma thickness, lymph node metastasis, and shorter overall, and disease-free survival of patients. Overexpression of miR-612 significantly decreased cell proliferation, colony formation, and invasion of SK-MEL-28 and A375 melanoma cells. In vivo tumorigenic studies confirmed that miR-612 overexpression retarded the growth of A375 xenograft tumors, which was coupled with a decline in the percentage of Ki-67-positive proliferating cells. Mechanistically, miR-612 targeted Espin in melanoma cells. Overexpression of Espin counteracted the suppressive effects of miR-612 on melanoma cell proliferation, invasion, and tumorigenesis. A significant inverse correlation (r = -0.376, P = 0.018) was observed between miR-612 and Espin protein expression in melanoma tissues. In addition, overexpression of miR-612 and knockdown of Espin significantly increased the sensitivity of melanoma cells to doxorubicin. Collectively, miR-612 suppresses the aggressive phenotype of melanoma cells through downregulation of Espin. Delivery of miR-612 may represent a novel therapeutic strategy against melanoma.

• Molecules and Cells
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• v.41 no.5
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• pp.486-494
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• 2018

Recently, we have reported that animals with telomerase reverse transcriptase (TERT) overexpression exhibit reduced social interaction, decreased preference for novel social interaction and poor nest-building behaviors-symptoms that mirror those observed in human autism spectrum disorders (ASD). Overexpression of TERT also alters the excitatory/inhibitory (E/I) ratio in the medial prefrontal cortex. However, the effects of TERT overexpression on hippocampal-dependent learning and synaptic efficacy have not been investigated. In the present study, we employed electrophysiological approaches in combination with behavioral analysis to examine hippocampal function of TERT transgenic (TERT-tg) mice and FVB controls. We found that TERT overexpression results in enhanced hippocampal excitation with no changes in inhibition and significantly impairs long-term synaptic plasticity. Interestingly, the expression levels of phosphorylated CREB and phosphorylated $CaMKII{\alpha}$ were significantly decreased while the expression level of $CaMKII{\alpha}$ was slightly increased in the hippocampus of TERT-overexpressing mice. Our observations highlight the importance of TERT in normal synaptic function and behavior and provide additional information on a novel animal model of ASD associated with TERT overexpression.

• Animal Bioscience
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• v.36 no.2
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• pp.200-208
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• 2023

Objective: Muscle acetylcholine receptors have five alpha subunits (α, β, δ, ε, or γ), and cholinergic receptor nicotinic gamma subunit (CHRNG) is the γ subunit. It may also play an essential role in biological processes, including cell differentiation, growth, and survival, while the role of CHRNG has not been studied in the literature. Therefore, the purpose of this study is to clarify the effect of CHRNG on the proliferation and differentiation of bovine preadipocytes. Methods: We constructed a CHRNG overexpression adenovirus vector and successfully overexpressed it on bovine preadipocytes. The effects of CHRNG on bovine preadipocyte proliferation were detected by Edu assay, cell counting Kit-8 (CCK-8), real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), Western blot and other techniques. We also performed oil red O, RT-qPCR, Western blot to explore its effect on the differentiation of preadipocytes. Results: The results of Edu proliferation experiments showed that the number of EDU-positive cells in the overexpression group was significantly less. CCK-8 experiments found that the optical density values of the cells in the overexpression group were lower than those of the control group, the mRNA levels of proliferating cell nuclear antigen (PCNA), cyclin A2 (CCNA2), cyclin B1 (CCNB1), cyclin D2 (CCND2) decreased significantly after CHRNG gene overexpression, the mRNA levels of cyclin dependent kinase inhibitor 1A (CDKN1A) increased significantly, and the protein levels of PCNA, CCNB1, CCND2 decreased significantly. Overexpression of CHRNG inhibited the differentiation of bovine preadipocytes. The results of oil red O and triglyceride determination showed that the size and speed of lipid droplets accumulation in the overexpression group were significantly lower. The mRNA and protein levels of peroxisome proliferator activated receptor gamma (PPAR class="checkNonKBPoint">γ), CCAAT enhancer binding protein alpha (CEBPα), fatty acid binding protein 4 (FABP4), fatty acid synthase (FASN) decreased significantly. Conclusion: Overexpression of CHRNG in bovine preadipocytes inhibits the proliferation and differentiation of bovine preadipocytes.

• 대한예방의학회:학술대회논문집
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• 2000.10a
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• pp.52-53
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• 2000

• Molecules and Cells
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• v.37 no.11
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• pp.785-794
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• 2014

Mitophagy, a cellular process that selectively targets dysfunctional mitochondria for degradation, is currently a hot topic in research into the pathogenesis and treatment of many human diseases. Considering that hypoxia causes mitochondrial dysfunction, which results in cell death, we speculated that selective activation of mitophagy might promote cell survival under hypoxic conditions. In the present study, we introduced the Regulator of calcineurin 1-1L (Rcan1-1L) to initiate the mitophagy pathway and aimed to evaluate the effect of Rcan1-1L-induced mitophagy on cell survival under hypoxic conditions. Recombinant adenovirus vectors carrying Rcan1-1L were transfected into human umbilical vein endothelial cells and human adult cardiac myocytes. Using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay and Trypan blue exclusion assay, Rcan1-1L overexpression was found to markedly reverse cell growth inhibition induced by hypoxia. Additionally, Rcan1-1L overexpression inhibited cell apoptosis under hypoxic conditions, as detected by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) apoptosis assay. Meanwhile, the mitochondria-mediated cell apoptotic pathway was inhibited by Rcan1-1L. In contrast, knockdown of Rcan1-1L accelerated hypoxia-induced cell apoptosis. Moreover, Rcan1-1L overexpression significantly reduced mitochondrial mass, decreased depolarized mitochondria, and downregulated ATP and reactive oxygen species production. We further delineated that the loss of mitochondrial mass was due to the activation of mitophagy induced by Rcan1-1L. Rcan1-1L overexpression activated autophagy flux and promoted translocation of the specific mitophagy receptor Parkin into mitochondria from the cytosol, whereas inhibition of autophagy flux resulted in the accumulation of Parkin-loaded mitochondria. Finally, we demonstrated that mitochondrial 1permeability transition pore opening was significantly increased by Rcan1-1L overexpression, which suggested that Rcan1-1L might evoke mitophagy through regulating mitochondrial permeability transition pores. Taken together, we provide evidence that Rcan1-1L overexpression induces mitophagy, which in turn contributes to cell survival under hypoxic conditions, revealing for the first time that Rcan1-1L-induced mitophagy may be used for cardioprotection.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.597-603
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• 1999

Caldesmon (CaD), one of microfilament-associated proteins, plays a key role in microfilament assembly in mitosis. We have investigated the effects of overexpression of the high molecular weight isoform of CaD (h-CaD) on the physiology of vascular smooth muscle cells (VSMCs). Rat aortic VSMCs were stably transfected with plasmids carrying a full length human h-CaD cDNA under control of cytomegalovirus promoter. The majority of the overexpressed h-CaD appears to be localized predominantly on cytoskeleton structures as determined by detergent lysis. The overexpression of h-CaD, however, does not decrease the level of endogenous low molecular weight isoform of CaD. h-CaD overexpressing VSMCs (h-CaD/VSMCs) show a decreased growth rate than that of vector-only transfected cells when determined by $[^3H]thymidine$ uptake and cell counting after fetal bovine serum (FBS) stimulation. h-CaD/VSMCs were smaller than vector-transfected cells by 18% in cell diameter. These data suggest that overexpression of h-CaD can inhibit the poliferation and the cell volume of VSMCs stimulated by growth factors and that the gene therapy with h-CaD may be helpful to prevent the conditions associated with hypertrophy and/or hyperplasia of VSMCs after arterial injuries.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.1
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• pp.71-77
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• 2012

Mitochondrial dynamics and distribution is critical for their role in bioenergetics and cell survival. We investigated the consequence of altered fission/fusion on mitochondrial function and motility in INS-1E rat clonal ${\beta}$-cells. Adenoviruses were used to induce doxycycline-dependent expression of wild type (WT-Mfn1) or a dominant negative mitofusin 1 mutant (DN-Mfn1). Mitochondrial morphology and motility were analyzed by monitoring mitochondrially-targeted red fluorescent protein. Adenovirus-driven overexpression of WT-Mfn1 elicited severe aggregation of mitochondria, preventing them from reaching peripheral near plasma membrane areas of the cell. Overexpression of DN-Mfn1 resulted in fragmented mitochondria with widespread cytosolic distribution. WT-Mfn1 overexpression impaired mitochondrial function as glucose- and oligomycin-induced mitochondrial hyperpolarization were markedly reduced. Viability of the INS-1E cells, however, was not affected. Mitochondrial motility was significantly reduced in WT-Mfn1 overexpressing cells. Conversely, fragmented mitochondria in DN-Mfn1 overexpressing cells showed more vigorous movement than mitochondria in control cells. Movement of these mitochondria was also less microtubule-dependent. These results suggest that Mfn1-induced hyperfusion leads to mitochondrial dysfunction and hypomotility, which may explain impaired metabolism-secretion coupling in insulin-releasing cells overexpressing Mfn1.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1825-1828
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• 2013

Overexpression of several aquaporins (AQPS) has been reported in different types of human cancer but roles in human carcinogenesis have yet to be clearly defined. Here, we up-regulated expression of the AQP8 gene in SiHa human cervical cancer cells with a lentivirus transfection system and investigated its effects as a potential therapeutic target for cervical cancer. Results showed AQP8 overexpression did not affect their substrate adherence and proliferation, but accelerated migration as assessed by transwell migration and wound healing assays. Moreover, AQP8 overexpression significantly enhanced local invasion of SiHa cells in nude mice. These findings altogether indicate that AQP8 overexpression increases migration of SiHa cells and probably participates in the process of tumor local invasion.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.233-237
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• 2015

Background: Lung cancer is the leading cause of cancer death in Brunei Darussalam, accounting for almost 20% of the total. The epidermal growth factor receptor (EGFR) is a member of the erbB family of tyrosine kinase receptor proteins, which includes c-erbb2(HER2/neu), erb-B3, and erb-B4. EGFR overexpression is found in a third of all epithelial cancers, often associated with a poor prognosis. Materials and Methods: Protein expression of EGFR in 27 cases of lung cancer tissue samples and 9 cases of normal lung tissue samples was evaluated using an immunohistochemical approach. Results: The results demonstrated significant increase and overexpression of EGFR in Bruneian lung cancer tissue samples in comparison to normal lung tissue. However, there was no significant relationship between clinicopathologic variables (age and sex) of patients and EGFR protein expression. Conclusions: EGFR is overexpressed in Bruneian lung cancer patient tissue samples in comparison to normal lung tissue samples. This may indicate that EGFR protein over expression plays an important role in the genesis of this type of cancer in Brunei Darussalam.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.895-901
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• 2013

Resistance to induction of apoptosis is a major obstacle for bladder cancer treatment. Bcl-2 is thought to be involved in anti-apoptotic signaling. In this study, we investigated the effect of Bcl-2 overexpression on apoptotic resistance and intracellular reactive oxygen species (ROS) generation in bladder cancer cells. A stable Bcl-2 overexpression cell line, BIU87-Bcl-2, was constructed from human bladder cancer cell line BIU87 by transfecting recombinant Bcl-2 [pcDNA3.1(+)-Bcl-2]. The sensitivity of transfected cells to adriamycin (ADR) was assessed by MTT assay. Apoptosis was examined by flow cytometry and acridine orange fluorescence staining. Intracellular ROS was determined using flow cytometry, and the activities of superoxide dismutase (SOD) and catalase (CAT) were also investigated by the xanthinoxidase and visible radiation methods using SOD and CAT detection kits. The susceptibility of BIU87-Bcl-2 cells to ADR treatment was significantly decreased as compared with control BIU87 cells. Enhanced expression of Bcl-2 inhibited intracellular ROS generation following ADR treatment. Moreover, the suppression of SOD and CAT activity induced by ADR treatment was blocked in the BIU87-Bcl-2 case but not in their parental cells. The overexpression of Bcl-2 renders human bladder cancer cells resistant to ADR-induced apoptosis and ROS might act as an important secondary messenger in this process.