• 생명과학회지
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• 제27권3호
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• pp.310-317
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• 2017

본 연구진은 HaCaT-ARE-luciferase 세포를 이용하여 400 여개의 약용식물 에탄올 추출물 중 NRF2/ARE 유도효과가 있는 신규 추출물을 검색하였고 이를 통하여 종대황(Rheum undulatum)과 선복화(Inula japonica)의 주정 추출물이 HaCaT-ARE-luciferase 세포에서 ARE 활성을 강하게 유도하는 것을 관찰하였다. 종대황과 선복화 에탄올 추출물은 HaCaT 세포에서 생존(viability)을 증가시켰고 NRF2/ARE에 의존적인 phase II cytoprotective 효소인 heme oxygenase-1 (HO-1)와 NADPH:quinone oxidoreductase-1 (NQO1)의 전사 및 단백질 발현을 강하게 유도하였다. 또한 종대황과 선복화 추출물은 HaCaT 세포에서 TPA로 유도한 세포 내 활성 산소 및 이를 통하여 생성되는 스트레스 마커인 8-hydroxydeoxyguanosine (8-OH-dG)과 4-hydroxynonenal (4HNE)의 발생을 강하게 억제하였다. 본 연구는 종대황과 선복화의 에탄올 추출물이 인간 피부 세포주인 HaCaT 세포에서 NRF2/ARE에 의존적인 유전자 발현의 유도를 통하여 강력한 항산화 효과를 발휘한다는 것을 증명한다.

• Anatomy and Cell Biology
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• 제50권3호
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• pp.207-213
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• 2017

Glycogen synthase kinase $(GSK)-3{\beta}$ and related enzymes are associated with various forms of neuroinflammation, including spinal cord injury (SCI). Our aim was to evaluate whether lithium, a non-selective inhibitor of $GSK-3{\beta}$, ameliorated SCI progression, and also to analyze whether lithium affected the expression levels of two representative $GSK-3{\beta}$-associated molecules, nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) (a target gene of Nrf-2). Intraperitoneal lithium chloride (80 mg/kg/day for 3 days) significantly improved locomotor function at 8 days post-injury (DPI); this was maintained until 14 DPI (P<0.05). Western blotting showed significantly increased phosphorylation of $GSK-3{\beta}$ (Ser9), Nrf-2, and the Nrf-2 target HO-1 in the spinal cords of lithium-treated animals. Fewer neuropathological changes (e.g., hemorrhage, inflammatory cell infiltration, and tissue loss) were observed in the spinal cords of the lithium-treated group compared with the vehicle-treated group. Microglial activation (evaluated by measuring the immunoreactivity of ionized calcium-binding protein-1) was also significantly reduced in the lithium-treated group. These findings suggest that $GSK-3{\beta}$ becomes activated after SCI, and that a non-specific enzyme inhibitor, lithium, ameliorates rat SCI by increasing phosphorylation of $GSK-3{\beta}$ and the associated molecules Nrf-2 and HO-1.

• Biomolecules & Therapeutics
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• 제24권5호
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• pp.482-488
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• 2016

Cancer stem cells (CSCs) are a subset of tumor cells, which are characterized by resistance against chemotherapy and environmental stress, and are known to cause tumor relapse after therapy. A number of molecular mechanisms underlie the chemoresistance of CSCs, including high expression levels of drug efflux transporters. We investigated the role of the antioxidant transcription factor NF-E2-related factor 2 (NRF2) in chemoresistance development, using a CSC-enriched colonosphere system. HCT116 colonospheres were more resistant to doxorubicin-induced cell death and expressed higher levels of drug efflux transporters such as P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) compared to HCT116 monolayers. Notably, levels of NRF2 and expression of its target genes were substantially elevated in colonospheres, and these increases were linked to doxorubicin resistance. When NRF2 expression was silenced in colonospheres, Pgp and BCRP expression was downregulated, and doxorubicin resistance was diminished. Collectively, these results indicate that NRF2 activation contributes to chemoresistance acquisition in CSC-enriched colonospheres through the upregulation of drug efflux transporters.

• 치위생과학회지
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• 제19권3호
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• pp.198-204
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• 2019

Background: Oxidative stress is a known to be associated with in the pathogenesis of many inflammatory diseases, including periodontitis. Ursolic acid is a pentacyclic triterpenoid with has antimicrobial, antioxidative, and anticancer properties. However, the role of ursolic acid in the regulating of osteogenesis remains undetermined. This study was aimed to elucidate the crucial osteogenic effects of ursolic acid and its ability to inhibit oxidative stress by targeting the immediate early response 3 (IER3)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Methods: Cell proliferation was determined using water-soluble tetrazolium salt assay, cell differentiation was evaluated by alkaline phosphatase (ALP) activity, and formation of calcium nodules was detected using alizarin red S stain. Generation of reactive oxygen species (ROS) was determined using by DCFH-DA fluorescence dye in hydrogen peroxide ($H_2O_2$)-treated MG-63 cells. Expression levels of IER3, Nrf2, and heme oxygenase-1 (HO-1) were analyzed using western blot analysis. Results: Our results showed that ursolic acid up-regulated the proliferation of osteoblasts without any cytotoxic effects, and promoted ALP activity and mineralization. $H_2O_2$-induced ROS generation was found to be significantly inhibited on treatment with ursolic acid. Furthermore, in $H_2O_2$-treated cells, the expression of the early response genes: IER3, Nrf2, and Nrf2-related phase II enzyme (HO-1) was enhanced in the presence of ursolic acid. Conclusion: The key findings of the present study elucidate the protective effects of ursolic acid against oxidative stress conditions in osteoblasts via the IER3/Nrf2 pathway. Thus, ursolic acid may be developed as a preventative and therapeutic agent for mineral homeostasis and inflammatory diseases caused due to oxidative injury.

• Archives of Plastic Surgery
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• 제41권6호
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• pp.654-660
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• 2014

Background Reactive oxygen species (ROS) damages cell molecules, and modifies cell signaling. The nuclear factor E2-related factor (Nrf2) is a critical transcription regulator, which protects cells against oxidative damage. Nrf2 expression is increased in a large number of cancers. However, little information has been reported regarding the expression of Nrf2 in skin cancers. Hence, we explored the expression of Nrf2 protein in skin cancers. Methods The Nrf2 protein expression in 24 specimens, including 6 malignant melanomas (MM), 6 squamous cell carcinomas (SCC), 6 basal cell carcinomas (BCC), and 6 normal skin tissues, was evaluated by western blotting. Immunohistochemical staining was performed. The expression of Kelch-like ECH-associated protein 1 (Keap1), the key regulator of Nrf2, was also analyzed by western blotting. Results Small interfering RNA transfection to the melanoma cell line G361 confirmed that an approximately 66 kDa band was the true Nrf2 band. The western blot revealed that the Nrf2 protein was definitely expressed in normal skin tissues, but the Nrf2 expression was decreased in MM, SCC, and BCC. Immunohistochemical examination showed that expression of Nrf2 was decreased in all skin cancer tissues compared to the normal skin tissues. Keap1 was not expressed in all malignant skin tumors and normal skin tissues by western blot. Conclusions ROS was increased in various types of cancers which proteins were highly expressed or underexpressed. This study demonstrated that the expression of Nrf2 protein was down-regulated in human malignant skin tumors. We suggest that decreased expression of Nrf2 is related to skin cancers.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.92-100
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• 2019

Ginger, one of worldwide consumed dietary spice, is not only famous as food supplements, but also believed to exert a variety of remarkable pharmacological activity as herbal remedies. In this study, a ginger constituent, 12-dehydrogingerdione (DHGD) was proven that has comparable anti-inflammatory activity with positive control 6-shogaol in inhibiting LPS-induced interleukin (IL)-6, tumor necrosis factor $(TNF)-{\alpha}$, prostaglandin (PG) $E_2$, nitric oxide (NO), inducible NO synthase (iNOS) and cyclooxygenase (COX)-2, without interfering with COX-1 in cultured microglial cells. Subsequent mechanistic studies indicate that 12-DHGD may inhibit neuro-inflammation through suppressing the LPS-activated $Akt/IKK/NF-{\kappa}B$ pathway. Furthermore, 12-DHGD markedly promoted the activation of NF-E2-related factor (Nrf)-2 and heme oxygenase (HO)-1, and we demonstrated that the involvement of HO-1 on the production of pro-inflammatory mediators such as NO and $TNF-{\alpha}$ by using a HO-1 inhibitor, Zinc protoporphyrin (Znpp). These results indicate that 12-DHGD may protect against neuro-inflammation by inhibiting $Akt/IKK/I{\kappa}B/NF-{\kappa}B$ pathway and promoting Nrf-2/HO-1 pathway.

• Molecules and Cells
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• 제38권5호
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• pp.416-425
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• 2015

NF-E2-related factor 2 (Nrf2), a basic leucine zipper transcription factor, has recently received a great deal of attention as an important molecule that enhances antioxidative defenses and induces resistance to chemotherapy or radiotherapy. In this study, we investigated the apoptosis-inducing and Nrf2- upregulating effects of quercetin on malignant mesothelioma (MM) MSTO-211H and H2452 cells. Quercetin treatment inhibited cell growth and led to upregulation of Nrf2 at both the mRNA and protein levels without altering the ubiquitination and extending the half-life of the Nrf2 protein. Following treatment with quercetin, analyses of the nuclear level of Nrf2, Nrf2 antioxidant response element-binding assay, Nrf2 promoter-luc assay, and RT-PCR toward the Nrf2-regulated gene, heme oxygenase-1, demonstrated that the induced Nrf2 is transcriptionally active. Knockdown of Nrf2 expression with siRNA enhanced cytotoxicity due to the induction of apoptosis, as evidenced by an increase in the level of proapoptotic Bax, a decrease in the level of antiapoptotic Bcl-2 with enhanced cleavage of caspase-3 and PARP proteins, the appearance of a sub-$G_0/G_1$ peak in the flow cytometric assay, and increased percentage of apoptotic propensities in the annexin V binding assay. Effective reversal of apoptosis was observed following pretreatment with the pan-caspase inhibitor Z-VAD. Moreover, Nrf2 knockdown exhibited increased sensitivity to the anticancer drug, cisplatin, presumably by potentiating the oxidative stress induced by cisplatin. Collectively, our data demonstrate the importance of Nrf2 in cytoprotection, survival, and drug resistance with implications for the potential significance of targeting Nrf2 as a promising strategy for overcoming resistance to chemotherapeutics in MM.

• 약학회지
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• 제55권6호
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• pp.466-472
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• 2011

NF-E2-related factor 2 (Nrf2), a master regulator of antioxidant genes in animals, has been associated with the resistance of cancer cells to several cytotoxic chemotherapeutics. Bortezomib, a reversible inhibitor of the 26S proteasome, is a novel class anti-cancer therapeutics approved for the treatment of refractory multiple myeloma. However, the molecular mechanism of drug-resistance remains elusive. In the present study, bortezomib sensitivity has been investigated in Nrf2 knockdown ovarian cancer cells. When Nrf2 expression is stably repressed using interfering RNA expression, bortezomib-induced apoptosis and cell death were significantly enhanced compared to nonspecific RNA control cells. Knockdown cells showed elevated expression in the catalytic subunit PSMB5, PSMB6, and PSMB7 compared to the control, and failed to induce heme oxygenase-1 expression following bortezomib treatment. These indicate that differential proteasome levels and altered expression of stress-response genes could be underlying mechanisms of bortezomib sensitization in Nrf2-inhibited ovarian cancer cells.

• 생명과학회지
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• 제23권6호
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• pp.736-742
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• 2013

Achyranthoside E dimethyl ester (AEDE)는 Achyranthes japonica에서 분리한 oleanolic acid glycoside이다. 본 연구에서는 대식세포에서 lipopolysaccharide (LPS)로 인한 nitric oxide (NO)의 생성에 미치는 AEDE의 효과를 관찰하고 그 작용 기전을 연구하였다. AEDE는 NO 생성과 inducible NO synthase (iNOS) 발현을 억제하였으며 세포에 독성을 유도하지 않았다. 또한 AEDE는 heme oxygenase-1 (HO-1)의 발현을 유도하였으며, HO-1 siRNA를 처리했을 때 AEDE가 iNOS의 발현을 억제하지 못하였다. AEDE는 HO-1의 발현에 관여하는 전사인자인 nuclear factor E2-related factor 2 (Nrf2)를 핵으로 이동시켰다. 한편 AEDE에 의한 HO-1의 발현은 phosphatidylinositol 3-kinase (PI-3K) 및 extracellular signal regulated kinase (ERK1/2) 억제제에 의해 감소되었으며, AEDE가 Akt와ERK1/2의 인산화를 유도하였다. 이상의 결과를 종합해보면, AEDE는 대식세포에서 PI-3K/Akt/ERK-Nrf2 신호전달과정을 통해 HO-1의 발현을 유도함으로써 NO와 같은 염증매개물질의 생성을 억제한다는 것을 알 수 있다. 이러한 연구결과는 AEDE가 항염증제로 사용될 수 있음을 시사한다.

• The Korean Journal of Pain
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• 제34권1호
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• pp.35-46
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• 2021

Background: The present investigation explored the therapeutic actions of oleuropein along with the possible signaling pathway involved in attenuating neuropathic pain in chronic constriction injury (CCI) and vincristine-induced neuropathic pain in male rats. Methods: Four loose ligatures were placed around the sciatic nerve to induce CCI, and vincristine (50 ㎍/kg) was injected for 10 days to develop neuropathic pain. The development of cold allodynia, mechanical allodynia, and mechanical hyperalgesia was assessed using different pain-related behavioral tests. The levels of H2S, cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), orexin, and nuclear factor erythroid-2-related factor 2 (Nrf2) were measured in the sciatic nerve. Results: Treatment with oleuropein for 14 days led to significant amelioration of behavioral manifestations of neuropathic pain in two pain models. Moreover, oleuropein restored both CCI and vincristine-induced decreases in H2S, CSE, CBS, orexin, and Nrf2 levels. Co-administration of suvorexant, an orexin receptor antagonist, significantly counteracted the pain-attenuating actions of oleuropein and Nrf2 levels without modulating H2S, CSE and CBS. Conclusions: Oleuropein has therapeutic potential to attenuate the pain manifestations in CCI and vincristine-induced neuropathic pain, possibly by restoring the CSE, CBS, and H2S, which may subsequently increase the expression of orexin and Nrf2 to ameliorate behavioral manifestations of pain.