Top

Archives

Archives
Previous​ Next
  • MinireviewFebruary 28, 2015

    7 101 1337

    Are Macrophages in Tumors Good Targets for Novel Therapeutic Approaches?

    Samthosh V Alahari, Shengli Dong, and Suresh K Alahari

    Mol. Cells 2015; 38(2): 95-104 https://doi.org/10.14348/molcells.2015.2298
    Abstract

    Abstract : The development of cancer has been an extensively researched topic over the past few decades. Although great strides have been made in cancer prevention, diagnosis, and treatment, there is still much to be learned about cancer’s micro-environmental mechanisms that contribute to cancer formation and aggressiveness. Macrophages, lymphocytes which originate from monocytes, are involved in the inflammatory response and often dispersed to areas of infection to fight harmful antigens and mutated cells in tissues. Macrophages have a plethora of roles including tissue development and repair, immune system functions, and inflammation. We discuss various pathways by which macrophages get activated, various approaches that can regulate the function of macrophages, and how these approaches can be helpful in developing new cancer therapies.

  • MinireviewFebruary 28, 2015

    22 116 2035
    Abstract

    Abstract : The beta2-adrenergic receptor (β2AR) family, which is the largest family of cell surface receptors in humans. Extra attention has been focused on the human GPCRs because they have been studied as important protein targets for pharmaceutical drug development. In fact, approximately 40% of marketed drugs directly work on GPCRs. GPCRs respond to various extracellular stimuli, such as sensory signals, neurotransmitters, chemokines, and hormones, to induce structural changes at the cytoplasmic surface, activating downstream signaling pathways, primarily through interactions with heterotrimeric G proteins or through G-protein independent pathways, such as arrestin. Most GPCRs, except for rhodhopsin, which contains covalently linked 11 cis-retinal, bind to diffusible ligands, having various conformational states between inactive and active structures. The first human GPCR structure was determined using an inverse agonist bound β2AR in 2007 and since then, more than 20 distinct GPCR structures have been solved. However, most GPCR structures were solved as inactive forms, and an agonist bound fully active structure is still hard to obtain. In a structural point of view, β2AR is relatively well studied since its fully active structure as a complex with G protein as well as several inactive structures are available. The structural comparison of inactive and active states gives an important clue in understanding the activation mechanism of β2AR. In this review, structural features of inactive and active states of β2AR, the interaction of β2AR with heterotrimeric G protein, and the comparison with β1AR will be discussed.

  • ArticleFebruary 28, 2015

    0 57 842

    14-3-3ζ Regulates Immune Response through Stat3 Signaling in Oral Squamous Cell Carcinoma

    Xinguang Han, Yongfu Han, Huifeng Jiao, and Yaqiong Jie

    Mol. Cells 2015; 38(2): 112-121 https://doi.org/10.14348/molcells.2015.2101
    Abstract

    Abstract : Ectopic expression of 14-3-3ζ has been found in various malignancies, including lung cancer, liver cancer, head and neck squamous cell carcinoma (HNSCC), and so on. However, the effect of 14-3-3ζ in the regulation of interactions between tumor cells and the immune system has not been previously reported. In this study, we aimed to investigate whether and how 14-3-3ζ is implicated in tumor inflammation modulation and immune recognition evasion. In oral squamous cell carcinoma (OSCC) cell lines and cancer tissues, we found that 14-3-3ζ is overexpressed. In OSCC cells, 14-3-3ζ knockdown resulted in the up-regulated expression of inflammatory cytokines. In contrast, 14-3-3ζ introduction attenuated cytokine expression in human normal keratinocytes and fibroblasts stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). Furthermore, supernatants from 14-3-3ζ knockdown OSCC cells dramatically altered the response of peritoneal macrophages, dendritic cells and tumor-specific T cells. Interestingly, Stat3 was found to directly interact with 14-3-3ζ and its disruption relieved the inhibition induced by 14-3-3ζ in tumor inflammation. Taken together, our studies provide evidence that 14-3-3ζ may regulate tumor inflammation and immune response through Stat3 signaling in OSCC.

  • ArticleFebruary 28, 2015

    2 42 419
    Abstract

    Abstract : DBM-2198, a six-membered azasugar nucleotide (6-AZN)-containing phosphorothioate (P = S) oligonucleotide (AZPSON), was described in our previous publication [Lee et al. (2005)] with regard to its antiviral activity against a broad spectrum of HIV-1 variants. This report describes the mechanisms underlying the anti-HIV-1 properties of DBM-2198. The LTR-mediated reporter assay indicated that the anti-HIV-1 activity of DBM-2198 is attributed to an extracellular mode of action rather than intracellular sequence-specific antisense activity. Nevertheless, the antiviral properties of DBM-2198 and other AZPSONs were highly restricted to HIV-1. Unlike other P = S oligonucleo-tides, DBM-2198 caused no host cell activation upon administration to cultures. HIV-1 that was pre-incubated with DBM-2198 did not show any infectivity towards host cells whereas host cells pre-incubated with DBM-2198 remained susceptible to HIV-1 infection, suggesting that DBM-2198 acts on the virus particle rather than cell surface molecules in the inhibition of HIV-1 infection. Competition assays for binding to HIV-1 envelope protein with anti-gp120 and anti-V3 antibodies revealed that DBM-2198 acts on the viral attachment site of HIV-1 gp120, but not on the V3 region. This report provides a better understanding of the antiviral mechanism of DBM-2198 and may contribute to the development of a potential therapeutic drug against a broad spectrum of HIV-1 variants.

  • ArticleFebruary 28, 2015

    26 99 755

    MicroRNA-576-3p Inhibits Proliferation in Bladder Cancer Cells by Targeting Cyclin D1

    Zhen Liang, Shiqi Li, Xin Xu, Xianglai Xu, Xiao Wang, Jian Wu, Yi Zhu, Zhenghui Hu, Yiwei Lin, Yeqing Mao, Hong Chen, Jindan Luo, Ben Liu, Xiangyi Zheng, and Liping Xie

    Mol. Cells 2015; 38(2): 130-137 https://doi.org/10.14348/molcells.2015.2146
    Abstract

    Abstract : MicroRNAs (miRNAs) are small, endogenous RNAs that play important gene-regulatory roles by binding to the imperfectly complementary sequences at the 3′-UTR of mRNAs and directing their gene expression. Here, we first discovered that miR-576-3p was down-regulated in human bladder cancer cell lines compared with the non-malignant cell line. To better characterize the role of miR-576-3p in bladder cancer cells, we over-expressed or down-regulated miR-576-3p in bladder cancer cells by transfecting with chemically synthesized mimic or inhibitor. The overexpression of miR-576-3p remarkably inhibited cell proliferation via G1-phase arrest, and decreased both mRNA and protein levels of cyclin D1 which played a key role in G1/S phase transition. The knock-down of miR-576-3p significantly promoted the proliferation of bladder cancer cells by accelerating the progression of cell cycle and increased the expression of cyclin D1. Moreover, the dual-luciferase reporter assays indicated that miR-576-3p could directly target cyclin D1 through binding its 3′-UTR. All the results demonstrated that miR-576-3p might be a novel suppressor of bladder cancer cell proliferation through targeting cyclin D1.

  • ArticleFebruary 28, 2015

    32 82 1500

    Raloxifene Induces Autophagy-Dependent Cell Death in Breast Cancer Cells via the Activation of AMP-Activated Protein Kinase

    Dong Eun Kim, Yunha Kim, Dong-Hyung Cho, Seong-Yun Jeong, Sung-Bae Kim, Nayoung Suh, Jung Shin Lee, Eun Kyung Choi, Jae-Young Koh, Jung Jin Hwang, and Choung-Soo Kim

    Mol. Cells 2015; 38(2): 138-144 https://doi.org/10.14348/molcells.2015.2193
    Abstract

    Abstract : Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

  • ArticleFebruary 28, 2015

    1 82 702

    NELL2 Function in the Protection of Cells against Endoplasmic Reticulum Stress

    Dong Yeol Kim, Han Rae Kim, Kwang Kon Kim, Jeong Woo Park, and Byung Ju Lee

    Mol. Cells 2015; 38(2): 145-150 https://doi.org/10.14348/molcells.2015.2216
    Abstract

    Abstract : Continuous intra- and extracellular stresses induce disorder of Ca2+ homeostasis and accumulation of unfolded protein in the endoplasmic reticulum (ER), which results in ER stress. Severe long-term ER stress triggers apoptosis signaling pathways, resulting in cell death. Neural epidermal growth factor-like like protein 2 (NELL2) has been reported to be important in protection of cells from cell death-inducing environments. In this study, we investigated the cytoprotective effect of NELL2 in the context of ER stress induced by thapsigargin, a strong ER stress inducer, in Cos7 cells. Overexpression of NELL2 prevented ER stress-mediated apoptosis by decreasing expression of ER stress-induced C/EBP homologous protein (CHOP) and increasing ER chaperones. In this context, expression of anti-apoptotic Bcl-xL was increased by NELL2, whereas NELL2 decreased expression of pro-apoptotic proteins, such as cleaved caspases 3 and 7. This anti-apoptotic effect of NELL2 is likely mediated by extracellular signal-regulated kinase (ERK) signaling, because its inhibitor, U0126, inhibited effects of NELL2 on the expression of anti- and pro-apoptotic proteins and on the protection from ER stress-induced cell death.

  • ArticleFebruary 28, 2015

    17 89 634
    Abstract

    Abstract : Matrix metalloproteinase (MMP)-9 degrades type IV collagen in the basement membrane and plays crucial roles in several pathological implications, including tumorigenesis and inflammation. In this study, we analyzed the effect of flavonols on MMP-9 expression in phorbol-12-myristate-13-acetate (PMA)-induced human fibrosarcoma HT-1080 cells. Galangin and kaempferol efficiently decreased MMP-9 secretion, whereas fisetin only weakly decreased its secretion. Galangin and kaempferol did not affect cell viability at concentrations up to 30 μM. Luciferase reporter assays showed that galangin and kaempferol decrease transcription of MMP-9 mRNA. Moreover, galangin and kaempferol strongly reduce IκBα phosphorylation and significantly decrease JNK phosphorylation. These results indicate that galangin and kaempferol suppress PMA-induced MMP-9 expression by blocking activation of NF-κB and AP-1. Therefore, these flavonols could be used as chemopreventive agents to lower the risk of diseases involving MMP-9.

  • ArticleFebruary 28, 2015

    3 62 670

    Tristetraprolin Inhibits the Growth of Human Glioma Cells through Downregulation of Urokinase Plasminogen Activator/Urokinase Plasminogen Activator Receptor mRNAs

    Jinhyun Ryu, Nal Ae Yoon, Yeon Kyung Lee, Joo Yeon Jeong, Seokmin Kang, Hyemin Seong, Jungil Choi, Nammi Park, Nayoung Kim, Wha Ja Cho, Sun Ha Paek, Gyeong Jae Cho, Wan Sung Choi, Jae-Yong Park, Jeong Woo Park, and Sang Soo Kang

    Mol. Cells 2015; 38(2): 156-162 https://doi.org/10.14348/molcells.2015.2259
    Abstract

    Abstract : Urokinase plasminogen activator (uPA) and urokinase plasminogen activator receptor (uPAR) play a major role in the infiltrative growth of glioblastoma. Downregulatoion of the uPA and uPAR has been reported to inhibit the growth glioblastoma. Here, we demonstrate that tristetraprolin (TTP) inhibits the growth of U87MG human glioma cells through downregulation of uPA and uPAR. Our results show that expression level of TTP is inversely correlated with those of uPA and uPAR in human glioma cells and tissues. TTP binds to the AU-rich elements within the 3′ untranslated regions of uPA and uPAR and overexpression of TTP decreased the expression of uPA and uPAR through enhancing the degradation of their mRNAs. In addition, overexpression of TTP inhibited the growth and invasion of U87MG cells. Our findings implicate that TTP can be used as a promising therapeutic target to treat human glioma.

  • ArticleFebruary 28, 2015

    5 87 887

    Lipoteichoic Acid Isolated from Lactobacillus plantarum Inhibits Melanogenesis in B16F10 Mouse Melanoma Cells

    Hye Rim Kim, Hangeun Kim, Bong Jun Jung, Ga Eun You, Soojin Jang, and Dae Kyun Chung

    Mol. Cells 2015; 38(2): 163-170 https://doi.org/10.14348/molcells.2015.2263
    Abstract

    Abstract : Lipoteichoic acid (LTA) is a major component of the cell wall of Gram-positive bacteria. Its effects on living organisms are different from those of lipopolysaccharide (LPS) found in Gram-negative bacteria. LTA contributes to immune regulatory effects including anti-aging. In this study, we showed that LTA isolated from Lactobacillus plantarum (pLTA) inhibited melanogenesis in B16F10 mouse melanoma cells. pLTA reduced the cellular activity of tyrosinase and the expression of tyrosinase family members in a dose-dependent manner. The expression of microphthalmia-associated transcription factor (MITF), a key factor in the synthesis of melanin, was also decreased by pLTA. Further, we showed that pLTA activated melanogenesis signaling, such as extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinse (PI3K)/AKT. In addition, the expression of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and HuR, which are important RNA-binding proteins (RBPs), was reduced. pLTA likely degrades MITF via regulation of melanogenic signaling and RNA stability of melanogenic proteins, resulting in the reduction of melanin. Thus, our data suggest that pLTA has therapeutic potential for treating hyperpigmentation disorders and can also be used as a cosmetic whitening agent.

Mol. Cells
Dec 31, 2021 Vol.44 No.12
COVER PICTURE
Structure of the fly peripheral neurons in the fly head. Flies have basic sensory organs including eyes for vision, antennae and maxillary palps for olfaction, and proboscis (magenta) for gustation which can be labelled with monoclonal antibody 22C10. The figure is a 3D reconstructed image with 30 slices of confocal sections with 3 μm interval. It shows that the proboscis is required for sensing attractive carboxylic acids such as glycolic acid, citric acid, and lactic acid (Shrestha and Lee, pp. 900-910).

Archives

Molecules and Cells

eISSN 0219-1032
qr-code Download