Docosahexaenoic acid induces autophagy through p53/AMPK/mTOR signaling and promotes apoptosis in human cancer cells harboring wild-type p53

Jing, Kaipeng,Song, Kyoung-Sub,Shin, Soyeon,Kim, Nayeong,Jeong, Soyeon,Oh, Hye-Rim,Park, Ji-Hoon,Seo, Kang-Sik,Heo, Jun-Young,Han, Jeongsu,Park, Jong-Il,Han, Chang,Wu, Tong,Kweon, Gi-Ryang,Park, Seung Taylor and Francis 2011 Autophagy Vol.7 No.11

Why is autophagy important in human diseases?

Kaipeng Jing,임규 생화학분자생물학회 2012 Experimental and molecular medicine Vol.44 No.2

The process of macroautophagy (referred to hereafter as autophagy), is generally characterized by the prominent formation of autophagic vesicles in the cytoplasm. In the past decades, studies of autophagy have been vastly expanded. As an essential process to maintain cellular homeostasis and functions, autophagy is responsible for the lysosome-mediated degradation of damaged proteins and organelles, and thus misregulation of autophagy can result in a variety of pathological conditions in human beings. Although our understanding of regulatory pathways that control autophagy is still limited, an increasing number of studies have shed light on the importance of autophagy in a wide range of physiological processes and human diseases. The goal of the reviews in the current issue is to provide a general overview of current knowledge on autophagy. The machinery and regulation of autophagy were outlined with special attention to its role in diabetes, neurodegenerative disorders, infectious diseases and cancer.

Downregulation of APE1/Ref-1 Is Involved in the Senescence of Mesenchymal Stem Cells

Heo, Jun-Young,Jing, Kaipeng,Song, Kyoung-Sub,Seo, Kang-Sik,Park, Ji-Hoon,Kim, Jong-Seok,Jung, Yeon-Joo,Hur, Gang-Min,Jo, Deog-Yeon,Kweon, Gi-Ryang,Yoon, Wan-Hee,Lim, Kyu,Hwang, Byung-Doo,Jeon, Byeong Wiley (John WileySons) 2009 Stem Cells Vol.27 No.6

<P>The senescence of human mesenchymal stem cells (hMSCs) causes disruption of tissue and organ maintenance, and is thus an obstacle to stem cell-based therapies for disease. Although some researchers have studied changes in the characteristics of hMSCs (decreases in differentiation ability and self-renewal), comparing young and old ages, the mechanisms of stem cell senescence have not yet been defined. In this study, we developed a growth curve for human bone marrow derived MSCs (hBMSCs) which changes into a hyperbolic state after passage number 7. Senescence associated beta-galactosidase (SA beta-gal) staining of hBMSCs showed 10% in passage 9 and 45% in passage 11. We detected an increase in endogenous superoxide levels during senescence that correlated with senescence markers (SA beta-gal, hyperbolic growth curve). Interestingly, even though endogenous superoxide increased in a replicative senescence model, the expression of APE1/Ref-1, which is sensitive to intracellular redox state, decreased. These effects were confirmed in a stress-induced senescence model by exogenous treatment with H(2)O(2). This change is related to the p53 activity that negatively regulates APE1/Ref-1. p21 expression levels, which represent p53 activity, were transiently increased in passage 9, meaning that they correlated with the expression of APE1/Ref-1. Overexpression of APE1/Ref-1 suppressed superoxide production and decreased SA beta-gal in hBMSCs. In conclusion, intracellular superoxide accumulation appears to be the main cause of the senescence of hBMSCs, and overexpression of APE1/Ref-1 can rescue cells from the senescence phenotype. Maintaining characteristics of hBMSCs by regulating intracellular reactive oxygen species production can contribute to tissue regeneration and to improved cell therapy.</P>

Docosahexaenoic Acid Induces Cell Death in Human Non-Small Cell Lung Cancer Cells by Repressing mTOR via AMPK Activation and PI3K/Akt Inhibition

Kim, Nayeong,Jeong, Soyeon,Jing, Kaipeng,Shin, Soyeon,Kim, Soyeon,Heo, Jun-Young,Kweon, Gi-Ryang,Park, Seung-Kiel,Wu, Tong,Park, Jong-Il,Lim, Kyu Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-

<P>The anticancer properties and mechanism of action of omega-3 polyunsaturated fatty acids (<I>ω</I>3-PUFAs) have been demonstrated in several cancers; however, the mechanism in lung cancer remains unclear. Here, we show that docosahexaenoic acid (DHA), a <I>ω</I>3-PUFA, induced apoptosis and autophagy in non-small cell lung cancer (NSCLC) cells. DHA-induced cell death was accompanied by AMP-activated protein kinase (AMPK) activation and inactivated phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling. Knocking down AMPK and overexpressing Akt increased mTOR activity and attenuated DHA-induced cell death, suggesting that DHA induces cell death via AMPK- and Akt-regulated mTOR inactivation. This was confirmed in Fat-1 transgenic mice, which produce <I>ω</I>3-PUFAs. Lewis lung cancer (LLC) tumor cells implanted into Fat-1 mice showed slower growth, lower phospho-Akt levels, and higher levels of apoptosis and autophagy than cells implanted into wild-type mice. Taken together, these data suggest that DHA-induced apoptosis and autophagy in NSCLC cells are associated with AMPK activation and PI3K/Akt inhibition, which in turn lead to suppression of mTOR; thus <I>ω</I>3-PUFAs may be utilized as potential therapeutic agents for NSCLC treatment.</P>

Induction of Angiogenesis by Matrigel Coating of VEGF-Loaded PEG/PCL-Based Hydrogel Scaffolds for hBMSC Transplantation

정연주,박종일,김경철,허준영,Kaipeng Jing,이경은,황준석,임규,조덕연,안재평,김진만,허강무 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.7

hBMSCs are multipotent cells that are useful for tissue regeneration to treat degenerative diseases and others for their differentiation ability into chondrocytes, osteoblasts, adipocytes, hepatocytes and neuronal cells. In this study, biodegradable elastic hydrogels consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(- caprolactone) (PCL) scaffolds were evaluated for tissue engineering because of its biocompatibility and the ability to control the release of bioactive peptides. The primary cultured cells from human bone marrow are confirmed as hBMSC by immunohistochemical analysis. Mesenchymal stem cell markers (collagen type I, fibronectin, CD54, integrin1 , and Hu protein) were shown to be positive, while hematopoietic stem cell markers (CD14 and CD45) were shown to be negative. Three different hydrogel scaffolds with different block compositions (PEG:PCL=6:14 and 14:6 by weight) were fabricated using the salt leaching method. The hBMSCs were expanded, seeded on the scaffolds, and cultured up to 8 days under static conditions in Iscove's Modified Dulbecco's Media (IMDM). The growth of MSCs cultured on the hydrogel with PEG/PCL= 6/14 was faster than that of the others. In addition, the morphology of MSCs seemed to be normal and no cytotoxicity was found. The coating of the vascular endothelial growth factor (VEGF) containing scaffold with Matrigel slowed down the release of VEGF in vitro and promoted the angiogene-sis when transplanted into BALB/c nude mice. These results suggest that hBMSCs can be supported by a biode gradable hydrogel scaffold for effective cell growth, and enhance the angiogenesis by Matrigel coating.

Induction of Angiogenesis by Matrigel Coating of VEGF-Loaded PEG/PCL-Based Hydrogel Scaffolds for hBMSC Transplantation

Jung, Yeon Joo,Kim, Kyung-Chul,Heo, Jun-Young,Jing, Kaipeng,Lee, Kyung Eun,Hwang, Jun Seok,Lim, Kyu,Jo, Deog-Yeon,Ahn, Jae Pyoung,Kim, Jin-Man,Huh, Kang Moo,Park, Jong-Il Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.7

hBMSCs are multipotent cells that are useful for tissue regeneration to treat degenerative diseases and others for their differentiation ability into chondrocytes, osteoblasts, adipocytes, hepatocytes and neuronal cells. In this study, biodegradable elastic hydrogels consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(${\varepsilon}$-caprolactone) (PCL) scaffolds were evaluated for tissue engineering because of its biocompatibility and the ability to control the release of bioactive peptides. The primary cultured cells from human bone marrow are confirmed as hBMSC by immunohistochemical analysis. Mesenchymal stem cell markers (collagen type I, fibronectin, CD54, $integrin1{\beta}$, and Hu protein) were shown to be positive, while hematopoietic stem cell markers (CD14 and CD45) were shown to be negative. Three different hydrogel scaffolds with different block compositions (PEG:PCL=6:14 and 14:6 by weight) were fabricated using the salt leaching method. The hBMSCs were expanded, seeded on the scaffolds, and cultured up to 8 days under static conditions in Iscove's Modified Dulbecco's Media (IMDM). The growth of MSCs cultured on the hydrogel with PEG/PCL= 6/14 was faster than that of the others. In addition, the morphology of MSCs seemed to be normal and no cytotoxicity was found. The coating of the vascular endothelial growth factor (VEGF) containing scaffold with Matrigel slowed down the release of VEGF in vitro and promoted the angiogenesis when transplanted into BALB/c nude mice. These results suggest that hBMSCs can be supported by a biode gradable hydrogel scaffold for effective cell growth, and enhance the angiogenesis by Matrigel coating.

인체 대장암 세포주 SW480에서 docosahexaenoic acid에 의한 침윤억제 기전

Soyeon Shin(신소연),Yong-Jo Kim(김용조),Kyoung-Sub Song(송경섭),Kaipeng Jing,Nayeong Kim(김나영),Soyeon Jeong(정소연),Ji-Hoon Park(박지훈),Kang-Sik Seo(서강식),Jun-Young Heo(허준영),Hyun-Joo Kwon(권현주),Jong-Il Park(박종일),Seung 한국생명과학회 2010 생명과학회지 Vol.20 No.4

대장암은 미국 등 서양 국가뿐만 아니라 국내에서도 2번째로 많이 발병이 되는 암으로 알려져 있다. 역학조사에 의하면 ω3-PUFAs를 많이 섭취한 인종에서 대장암 발생빈도가 감소하고 최근 ω3-PUFAs는 수종의 암에 대해 항암작용을 나타낸다고 한다. 이에 본 연구에서는 대장암에서 DHA 등 ω3-PUFA의 항침윤 기전을 규명하여 다음과 같은 결과를 얻었다. DHA 및 EPA는 대장암 세포주 SW480의 증식을 농도 의존적으로 억제하였으나 AA는 거의 영향이 없었으며 TUNEL assay로 apoptotic cell death가 확인 되었다. DHA는 β-catenin 단백 및 TCF/LEF luciferase 활성을 농도 의존적으로 억제 하였다. SW480 세포의 침윤능은 DHA의 농도에 의존적으로 억제되었다. DHA처리 후 MMP-9 및 MMP-2 mRNA양이 감소되었을 뿐만 아니라 그 promoter의 reporter 활성도 억제되었다. NF-kB 및 p-IkB 단백짙양도 DHA의 처리농도에 의존적으로 감소하였으며 NF-kB promoter의 활성도 억제되었다. 이상의 결과로 ω3-PUFA는 대장암에서 NF-kB 신호전달 차단에 의한 MMP-2 및 MMP-9 발현을 억제하여 침윤을 억제하여 항암작용을 나타낼 수 있음을 시사하며, 따라서 ω3-PUFA는 대장암의 예방 및 치료에 유용하게 사용될 수 있으리라 생각된다. Colon cancer is one of the most common malignancies in the western world and the second leading cause of cancer death in Korea. Epidemiology studies have shown a reduced incidence of colon cancer among populations consuming a large quantity of ω3-polyunsaturated fatty acids (ω3-PUFA) of marine origin. Recently, it has been found that ω3-PUFA has an antineoplastic effect in several cancers. This study was designed to investigate the mechanism of the anti-invasive effect of ω3-PUFA in colon cancer. ω3-PUFA, docosahexaenoic acids (DHA) and eicosapentaenoic acid (EPA) treatment resulted in a dose-dependent inhibition of cell growth in SW480 human colon cancer cells. In contrast, arachidonic acid (AA), a ω6-PUFA, exhibited no significant effect. This action likely involves apoptosis, given that DHA treatment increased apoptotic cells in TUNEL assay. Moreover, invasiveness of SW480 cells was inhibited following treatment of DHA in a dose-dependent manner; in contrast, AA had no effect. The levels of MMP-9 and MMP-2 mRNA decreased after DHA pretreatment. MMP-9 and MMP-2 promoter activities were also inhibited by DHA treatment. The levels of NF-kB and p-IkB protein were down-regulated by DHA pretreatment in a dose dependent manner. In addition, DHA inhibited NF-kB promoter reporter activities. These findings suggest that ω3-PUFA may inhibit cancer cell invasion by inhibition of MMPs via reduction of NF-kB in colon cancer. In conclusion, ω3-PUFA could be used for chemoprevention and treatment of human colon cancer.

인체 구강암 세포주에서 Docosahexaenoic acid에 의한 세포독성 기전

홍태화(Tae-hwa Hong),김훈(Hoon Kim),신소연(Soyeon Shin),Kaipeng Jing,정소연(Soyeon Jeong),임현(Hyun Lim),윤동혁(Donghyuk Yun),정기은(Ki-Eun Jeong),이명렬(Myung-Ryul Lee),박종일(Jong-Il Park),권기량(Gi-Ryang Kweon),박승길(Seung Kiel 한국생명과학회 2013 생명과학회지 Vol.23 No.5

오메가-3 지방산은 많은 암에서 세포독성을 나타낸다고 보고 되어 왔으나 구강암에 대한 연구는 전혀 없다. 이에 본 연구에서는 구강암세포에서 오메가-3 지방산 중 DHA의 세포독성 기전을 규명하여 다음과 같은 결과를 얻었다. DHA는 구강암 세포주 SCC-4 및 SCC-9의 증식을 농도 의존적으로 억제하였으며, FACS 분석, TUNEL assay 및 PARP cleavage 등에 의해 자가사멸을 유도함이 확인 되었다. 또한 DHA는 LC-3II 단백증가, GFP-LC-3 dot 형성 및 autophagic flux assay 등에 의해 자가포식도 유도됨이 규명되었다. SCC-9 세포에서 AMPK의 인산화는 DHA 에 의해 증가 하였으나, p-AKT^Thr308, p-AKT^Ser473 및 mTOR단백양은 감소하였다. 이상의 결과로 DHA는 구강암세포에서 AMPK 활성증가 및 AKT 억제에 통한 mTOR 신호경로 차단에 따른 자가사멸 및 자가포식에 의해 세포독성을 나타낼 수 있음을 시사하며, 따라서 DHA는 구강암의 예방 및 치료에 유용하게 사용될 수 있으리라 생각된다. In the United States, about 40,000 new cases of oral cancer are diagnosed each year and nearly 7,800 patients died from it in 2012. Omega-3 polyunsaturated fatty acids have been found to have anticancer effects in a variety of cancer cell lines and animal models, but their effect in oral cancer remains unclear. This study was designed to examine the effect of docosahexaenoic acid (DHA, a kind of omega- 3 fatty acid) on oral cancer cells and the molecular mechanism of its action. We found that exposure of squamous cell carcinoma-4 (SCC-4) and squamous cell carcinoma-9 (SCC-9) human oral cancer cells to DHA induced growth inhibition in a dose- and time-dependent manner. Meanwhile, in addition to the elevated levels of apoptotic markers, such as cleaved PARP, subG1 portion and TUNEL-positive nuclei, DHA led to autophagic vesicle formation and an increase in autophagic flux, indicating the involvement of both apoptosis and autophagy in the inhibitory effects of DHA on oral cancer cells. Further experiments revealed that the apoptosis and autophagy induced by DHA were linked to inhibition of mammalian target of rapamycin (mTOR) signaling by AKT inhibition and AMP-activated protein kinase (AMPK) activation in SCC-9 cells. Together, our results suggest that DHA induces apoptosis- and autophagy-associated cell death through the AMPK/AKT/mTOR signaling pathway in oral cancer cells. Thus, utilization of omega-3 fatty acids may represent a promising therapeutic approach for chemoprevention and treatment of human oral cancer.