• Title/Summary/Keyword: cause-effect pathway

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In Search for a Common Pathway for Health Issues in Men - the Sign of a Holmesian Deduction

  • Aoun, Fouad;Chemaly, Anthony Kallas;Albisinni, Simone;Zanaty, Marc;Roumeguere, Thierry
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.1
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    • pp.1-13
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    • 2016
  • The evidence for the existence of a common pathway for health issues in men is presented in this review. Several epidemiological studies have shown that conditions like cardiovascular diseases (CVD), metabolic syndrome, diabetes, lower urinary tract symptom (LUTS), erectile dysfunction (ED), prostate cancer, hypogonadism, depression and suicide can be associated as risk factors for each other. Thus, the risk of CVD is significantly increased in men with metabolic syndrome, ED, hypogonadism, prostate cancer and/or LUTS. In addition, the above mentioned conditions are more prevalent in atherosclerotic patients. In addition, growing evidence indicates that low androgen levels can cause metabolic syndrome. In addition, obesity, dyslipidaemia and diabetes can further reduce androgen levels potentiating their adverse effect. Low testosterone levels are also associated with a higher incidence of aggressive prostate cancer on biopsy and on definitive pathology, and lower probability of abiraterone response in the metastatic setting. Several recent studies point towards diffuse endothelial dysfunction and dysregulated pro-inflammatory state as the biological link between all these disorders. Our current hypothesis is that oxidative stress caused by these dysfunctions explains the pathogenesis of each of these conditions.

Sequential administration of camptothecin sensitizes human colon cancer HCT116 cells to paclitaxel via $p21^{Cip1/WAF1}$

  • Yoo, Jung-Min;Kim, Yun-Jin;Lee, Sung-Jae;Kim, Sang-Hoon
    • Animal cells and systems
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    • v.15 no.1
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    • pp.9-17
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    • 2011
  • Colorectal cancer is the third leading cause of cancer-related death in Western countries. Chemotherapeutic agents with different mechanisms of action have shown an increase in cure rates. In the present study, we investigated the effect of a combination of low concentration of paclitaxel (taxol, 5 nM) and topoisomerase 1 inhibitor camptothecin (CPT) on HCT116 colon cancer cells. Although the viability of cells treated with taxol alone was similar to that of control cells, sequential treatment with taxol and CPT exhibited high cytotoxicity. However, the opposite sequence of treatment did not exert cytotoxic effects on HCT116 cells. This enhanced cytotoxicity of the sequential combination therapy was the result of mitotic arrest, which increased the level of $p21^{Cip1/WAF1}$ through the p38 mitogen-activated protein kinase (MAPK) pathway. Knockdown by $p21^{Cip1/WAF1}$ siRNA or treatment with a p38 inhibitor reduced the viability of cells sequentially exposed to taxol and CPT. Taken together, a low taxol concentration in combination with CPT induced mitotic arrest in HCT116 cells, leading to synergistic cell death through enhanced expression of $p21^{Cip1/WAF1}$ and p38 MAPK pathway. Therefore, taxol could playa role as a sensitizer of CPT in colon cancer cells.

Clostridium difficile Toxin A Upregulates Bak Expression through PGE2 Pathway in Human Colonocytes

  • Kim, Young Ha;Kim, Ho
    • Journal of Microbiology and Biotechnology
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    • v.29 no.10
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    • pp.1675-1681
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    • 2019
  • Clostridium difficile toxin A is known to cause colonic epithelial cell apoptosis, which is considered the main causative event that triggers inflammatory responses in the colon, reflecting the concept that the essential role of epithelial cells in the colon is to form a physical barrier in the gut. We previously showed that toxin A-induced colonocyte apoptosis and subsequent inflammation were dependent on prostaglandin E2 ($PGE_2$) produced in response to toxin A stimulation. However, the molecular mechanism by which $PGE_2$ mediates cell apoptosis in toxin A-exposed colonocytes has remained unclear. Here, we sought to identify the signaling pathway involved in toxin A-induced, $PGE_2$-mediated colonocyte apoptosis. In non-transformed NCM460 human colonocytes, toxin A exposure strongly upregulated expression of Bak, which is known to form mitochondrial outer membrane pores, resulting in apoptosis. RT-PCR analyses revealed that this increase in Bak expression was attributable to toxin A-induced transcriptional upregulation. We also found that toxin A upregulation of Bak expression was dependent on $PGE_2$ production, and further showed that this effect was recapitulated by an Prostaglandin E2(PGE2) receptor-1 receptor agonist, but not by agonists of other EP receptors. Collectively, these results suggest that toxin A-induced cell apoptosis involves $PGE_2$-upregulation of Bak through the EP1 receptor.

Protective effects and mechanism of coenzyme Q10 and vitamin C on doxorubicin-induced gastric mucosal injury and effects of intestinal flora

  • Zhao, Xiaomeng;Feng, Xueke;Ye, Nan;Wei, Panpan;Zhang, Zhanwei;Lu, Wenyu
    • The Korean Journal of Physiology and Pharmacology
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    • v.25 no.4
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    • pp.261-272
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    • 2021
  • Doxorubicin (Dox) is widely used to the treatment of cancer, however, it could cause damage to gastric mucosa. To investigate the protective effects and related mechanisms of coenzyme Q10 (CoQ10) and vitamin C (VC) on Dox-induced gastric mucosal injury, we presented the survey of the 4 groups of the rats with different conditions. The results showed Dox treatment significantly induced GES-1 apoptosis, but preconditioning in GES-1 cells with VC or CoQ10 significantly inhibited the Dox-induced decrease and other harm effects, including the expression and of IκKβ, IκBα, NF-κB/p65 and tumor necrosis factor (TNF-α) in GES-1 cells. Moreover, high-throughput sequencing results showed Dox treatment increased the number of harmful gut microbes, and CoQ10 and VC treatment inhibited this effect. CoQ10 and VC treatment inhibits Dox-induced gastric mucosal injury by inhibiting the activation of the IkKB/IκBα/NF-κB/p65/TNF-α pathway, promoting anti-inflammatory effects of gastric tissue and regulating the composition of the intestinal flora.

Activation of $PPAR{\alpha}$ Attenuates $IFNP{\gamma}$ and IL-$1{\beta}$-induced Cell Proliferation in Astrocytes: Involvement of IL-6 Independent Pathway

  • Lee, Jin-Koo;Seo, Eun-Min;Lee, Sang-Soo;Park, Soo-Hyun;Sim, Yun-Beom;Jung, Jun-Suh;Kim, Seon-Mi;Suh, Hong-Won
    • The Korean Journal of Physiology and Pharmacology
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    • v.14 no.3
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    • pp.185-189
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    • 2010
  • The present study demonstrates the effect of fibrates, agonists of $PPAR{\alpha}$ on cytokines-induced proliferation in primary cultured astrocytes. Alone or combination treatment with cytokines, such as IL-$1{\beta}$ (10 ng/ml), $IFNP{\gamma}$ (10 ng/ml), and TNF-$\alpha$ (10 ng/ml) cause a significant increase of cell proliferation in a time-dependent manner. Treatment of astrocytes with bezafibrate and fenofibrate (0, 5, and $10\;{\mu}M$) reduced the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation in a dose-dependent manner. To address the involvement of IL-6 on the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation, released IL-6 level was measured. $IFNP{\gamma}$ and IL-$1{\beta}$ cause an increase of released IL-6 protein level in a time-dependent manner. Furthermore, pretreatment with IL-6 antibody (0, 0.1, 1, 2.5, and 5 ng/ml) dose-dependently inhibited the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation. However, bezafibrate and fenofibrate did not affect increased mRNA and protein levels of IL-6 in $IFNP{\gamma}$ and IL-$1{\beta}$-stimulated astrocytes. Taken together, these results clearly suggest that activation of $PPAR{\alpha}$ attenuates the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation through IL-6 independent pathway.

The Mechanism of Crinum asiaticum var. japonicum on the Activation of Anagen (문주란의 모발 성장기 유도 기전)

  • Kang, Jung-Il;Choi, Ju Hwan;Lee, Jong Gun;Yoo, Eun-Sook;Kim, Young Ho;Kang, Hee-Kyoung
    • Korean Journal of Pharmacognosy
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    • v.48 no.2
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    • pp.148-154
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    • 2017
  • Crinum asiaticum var. japonicum and its active component, norgalanthamine have been reported to have hair growth-promoting effect via the proliferation of dermal papilla cells. In this study, we investigated the other mechanisms of C. asiaticum extract var. japonicum and norgalanthamine on the hair growth. The C. asiaticum var. japonicum extract inhibited $5{\alpha}$-reductase activity by 16%, which converts testosterone to dihydrotestosterone (DHT), a main cause of androgenetic alopecia, whereas the C. asiaticum var. japonicum extract didn't function as an opener of the $K_{ATP}$ channel. On the other hand, we examined whether norgalanthamine can inhibit transforming growth factor-${\beta}$ (TGF-${\beta}$) signal pathway, which is essential in the regression induction of hair growth. Norgalanthamine inhibited the phosphorylation of Smad2/3 on TGF-${\beta}1$-induced canonical pathway in human keratinocyte HaCaT cells. These results suggested that the C. asiaticum var. japonicum extract and norgalanthamine had the potential to influence hair growth through the inhibition of $5{\alpha}$-reductase activity and TGF-${\beta}1$-induced canonical pathway.

Myonectin inhibits adipogenesis in 3T3-L1 preadipocytes by regulating p38 MAPK pathway

  • Park, Tae-Jun;Park, Anna;Kim, Jaehoon;Kim, Jeong-Yoon;Han, Baek Soo;Oh, Kyoung-Jin;Lee, Eun Woo;Lee, Sang Chul;Bae, Kwang-Hee;Kim, Won Kon
    • BMB Reports
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    • v.54 no.2
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    • pp.124-129
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    • 2021
  • In current times, obesity is a major health problem closely associated with metabolic disease such as diabetes, dyslipidemia, and cardiovascular disease. The direct cause of obesity is known as an abnormal increase in fat cell size and the adipocyte pool. Hyperplasia, the increase in number of adipocytes, results from adipogenesis in which preadipocytes differentiate into mature adipocytes. Adipogenesis is regulated by local and systemic cues that alter transduction pathways and subsequent control of adipogenic transcription factors. Therefore, the regulation of adipogenesis is an important target for preventing obesity. Myonectin, a member of the CTRP family, is a type of myokine released by skeletal muscle cells. Although several studies have shown that myonectin is associated with lipid metabolism, the role of myonectin during adipogenesis is not known. Here, we demonstrate the role of myonectin during adipocyte differentiation of 3T3-L1 cells. We found that myonectin inhibits the adipogenesis of 3T3-L1 preadipocytes with a reduction in the expression of adipogenic transcription factors such as C/EBPα, β and PPARγ. Furthermore, we show that myonectin has an inhibitory effect on adipogenesis through the regulation of the p38 MAPK pathway and CHOP. These findings suggest that myonectin may be a novel therapeutic target for the prevention of obesity.

DFT/B3LYP Study of the Substituent Effects on the Reaction Enthalpies of the Antioxidant Mechanisms of Magnolol Derivatives in the Gas-Phase and Water

  • Najafi, Meysam;Najafi, Mohammad;Najafi, Houshang
    • Bulletin of the Korean Chemical Society
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    • v.33 no.11
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    • pp.3607-3617
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    • 2012
  • In this paper, the study of various ortho- and meta-substituted Magnolol derivatives is presented. The reaction enthalpies related to three antioxidant action mechanisms HAT, SET-PT and SPLET for substituted Magnolols have been calculated using DFT/B3LYP method in gas-phase and water. Calculated results show that electron-withdrawing substituents increase the bond dissociation enthalpy (BDE), ionization potential (IP) and oxidation/reduction enthalpy (O/RE), while electron-donating ones cause a rise in the proton dissociation enthalpy (PDE) and proton affinity (PA). In ortho- position, substituents show larger effect on reaction enthalpies than in meta-position. In comparison to gas-phase, water attenuates the substituent effect on all reaction enthalpies. In gas-phase, BDEs are lower than PAs and IPs, i.e. HAT represents the thermodynamically preferred pathway. On the other hand, SPLET mechanism represents the thermodynamically favored process in water. Results show that calculated enthalpies can be successfully correlated with Hammett constants (${\sigma}_m$) of the substituted Magnolols. Furthermore, calculated IP and PA values for substituted Magnolols show linear dependence on the energy of the highest occupied molecular orbital ($E_{HOMO}$).

3',4',5',5,7-Pentamethoxyflavone Sensitizes Cisplatin-Resistant A549 Cells to Cisplatin by Inhibition of Nrf2 Pathway

  • Hou, Xiangyu;Bai, Xupeng;Gou, Xiaoli;Zeng, Hang;Xia, Chen;Zhuang, Wei;Chen, Xinmeng;Zhao, Zhongxiang;Huang, Min;Jin, Jing
    • Molecules and Cells
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    • v.38 no.5
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    • pp.396-401
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    • 2015
  • Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important redox-sensitive transcription factor that regulates the expression of several cytoprotective genes. More recently, genetic analyses of human tumors have indicated that Nrf2 may cause resistance to chemotherapy. In this study, we found that the expression levels of Nrf2 and its target genes GCLC, HO-1, NQO1 were significantly higher in cisplatin-resistant A549 (A549/CDDP) cells than those in A549 cells, and this resistance was partially reversed by Nrf2 siRNA. 3,4,5,5,7-Pentamethoxyflavone (PMF), a natural flavon extracted from Rutaceae plants, sensitized A549/CDDP to CDDP and substantially induced apoptosis compared with that of CDDP alone treated group, and this reversal effect decreased when Nrf2 was downregulated by siRNA. Mechanistically, PMF reduced Nrf2 expression leading to a reduction of Nrf2 downstream genes, and in contrast, this effect was decreased by blocking Nrf2 with siRNA. Taken together, these results demonstrated that PMF could be used as an effective adjuvant sensitizer to increase the efficacy of chemotherapeutic drugs by downregulating Nrf2 signaling pathway.

Gonadotropin-releasing Hormone and Its Receptor as a Therapeutic Concept in the Progression of Epithelial Ovarian Cancer

  • Kim, Ki-Yon;Choi, Kyung-Chul
    • Journal of Embryo Transfer
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    • v.24 no.1
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    • pp.1-14
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    • 2009
  • Ovarian cancer is a significant cause of cancer-related death in women, but the main biological causes remain open questions. Hormonal factors have been considered to be an important determinant causing ovarian cancer. Recent studies have shown that gonadotropin-releasing hormone (GnRH)-I and its analogs have clinically therapeutic value in the treatment of ovarian cancer. In addition, numerous studies have shown that the potential of GnRH-II in normal reproductive system or reproductive disorder. GnRH-I receptors have been detected in approximately 80% of ovarian cancer biopsy specimens as well as normal ovarian epithelial cells and immortalized ovarian surface epithelium cells. GnRH-II receptors have also been found to be more widely expressed than GnRH-I receptors in mammals, suggesting that GnRH receptors may have additional functions in reproductive system including ovarian cancer. The signal transduction pathway following the binding of GnRH to GnRH receptor has been extensively studied. The activation of protein kinase A/C (PKA/PKC) pathway is involved in the GnRH-I induced anti-proliferative effect in ovarian cancer cells. In addition, GnRH-I induced mitogen-activated protein kinase (MAPK) activation plays a role in anti-proliferative effect and apoptosis in ovarian cancer cells and the activation of transcriptional factors related to cellular responses. However, the role of GnRH-I and II receptors, there are discrepancies between previous reports. In this review, the role of GnRH in ovarian cancer and the mechanisms to induce anti-proliferation were evaluated.