• Molecules and Cells
• /
• 제45권9호
• /
• pp.660-672
• /
• 2022

The target of rapamycin complex (TORC) plays a key role in plant cell growth and survival by regulating the gene expression and metabolism according to environmental information. TORC activates transcription, mRNA translation, and anabolic processes under favorable conditions, thereby promoting plant growth and development. Tomato fruit ripening is a complex developmental process promoted by ethylene and specific transcription factors. TORC is known to modulate leaf senescence in tomato. In this study, we investigated the function of TORC in tomato fruit ripening using virus-induced gene silencing (VIGS) of the TORC genes, TOR, lethal with SEC13 protein 8 (LST8), and regulatory-associated protein of TOR (RAPTOR). Quantitative reverse transcription-polymerase chain reaction showed that the expression levels of tomato TORC genes were the highest in the orange stage during fruit development in Micro-Tom tomato. VIGS of these TORC genes using stage 2 tomato accelerated fruit ripening with premature orange/red coloring and decreased fruit growth, when control tobacco rattle virus 2 (TRV2)-myc fruits reached the mature green stage. TORC-deficient fruits showed early accumulation of carotenoid lycopene and reduced cellulose deposition in pericarp cell walls. The early ripening fruits had higher levels of transcripts related to fruit ripening transcription factors, ethylene biosynthesis, carotenoid synthesis, and cell wall modification. Finally, the early ripening phenotype in Micro-Tom tomato was reproduced in the commercial cultivar Moneymaker tomato by VIGS of the TORC genes. Collectively, these results demonstrate that TORC plays an important role in tomato fruit ripening by modulating the transcription of various ripening-related genes.

• Animal Bioscience
• /
• 제35권9호
• /
• pp.1444-1453
• /
• 2022

Objective: Acetate plays an important role in host lipid metabolism. However, the network of acetate-regulated lipid metabolism remains unclear. Previous studies show that mitogen-activated protein kinases (MAPKs) and mechanistic target of rapamycin (mTOR) play a crucial role in lipid metabolism. We hypothesize that acetate could affect MAPKs and/or mTOR signaling and then regulate lipid metabolism. The present study investigated whether any cross talk occurs among MAPKs, mTOR and acetate in regulating lipid metabolism. Methods: The ceramide C6 (an extracellular signaling-regulated kinases 1 and 2 [ERK1/2] activator) and MHY1485 (a mTOR activator) were used to treat rabbit adipose-derived stem cells (ADSCs) with or without acetate, respectively. Results: It indicated that acetate (9 mM) treatment for 48 h decreased the lipid deposition in rabbit ADSCs. Acetate treatment decreased significantly phosphorylated protein levels of ERK1/2 and mTOR but significantly increased mRNA level of hormone-sensitive lipase (HSL). Acetate treatment did not significantly alter the phosphorylated protein level of p38 MAPK and c-Jun aminoterminal kinase (JNK). Activation of ERK1/2 and mTOR by respective addition in media with ceramide C6 and MHY1485 significantly attenuated decreased lipid deposition and increased HSL expression caused by acetate. Conclusion: Our results suggest that ERK1/2 and mTOR signaling pathways are associated with acetate regulated HSL gene expression and lipid deposition.

• 한국식품영양과학회지
• /
• 제45권12호
• /
• pp.1708-1716
• /
• 2016

Akt 및 mTOR는 세포 생존에 필수적인 경로로 세포 성장과 증식 등에서 중요한 역할을 하는 것으로 알려져 있다. 본 연구에서는 항암 및 항균 효과가 있는 것으로 알려진 개똥쑥(Artemisia annua L.)에 의한 HepG2 간암세포의 apoptosis 유도 효과를 확인하였다. 본 연구 결과에 의하면 개똥쑥 추출물의 처리 농도가 증가함에 따라 HepG2 세포의 생존율은 억제되었으며, 이는 apoptosis 유도 효과에 의한 것임을 세포의 형태적 변화와 flow cytometry를 통해 확인하였다. 그리고 mitopotential assay와 caspase-3/7 activity assay, western blotting으로 Bcl-2 family 단백질을 확인함으로써 apoptosis 경로 중 내인성 경로(intrinsic pathway)에 의해 apoptosis가 일어남을 알 수 있었다. 이러한 효과는 Akt/mTOR의 활성 저해와 연관이 있었으며 Akt/mTOR의 저해제인 LY294002/rapamycin을 개똥쑥 추출물과 병행처리하였을 경우 개똥쑥 추출물에 의한 apoptosis 효과를 더욱 증대시켰다. 따라서 Akt/mTOR의 저해는 개똥쑥 추출물의 apoptosis 효과를 상승시켰으며 이에 따라 미토콘드리아의 기능 손상과 caspase 활성의 증가를 통해 이루어짐을 확인하였다.

• Tuberculosis and Respiratory Diseases
• /
• 제75권1호
• /
• pp.9-17
• /
• 2013

Background: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. Methods: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. Results: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-$G_1$ phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. Conclusion: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 2001년도 한국생물과학협회 학술발표대회
• /
• pp.194.1-194
• /
• 2001

No Abstract, See Full Text

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1998년도 공동 춘계학술대회
• /
• pp.57.2-57
• /
• 1998

No Abstract, See Full Text

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
• /
• pp.190.1-190
• /
• 1997

No Abstract, See Full Text

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권6호
• /
• pp.3725-3728
• /
• 2013

Background: The mammalian target of rapamycin (mTOR) /RPS6KB1 activation has recently been implicated in tumour development, but its role in lung cancer remains unclear. The aim of this study was to explore the role of mTOR/RPS6KB1 signaling pathway in non-small-cell lung cancer (NSCLC). Methods: Immunohistochemistry was performed to assess the expression of phosphorylated mammalian target of rapamycin (p-mTOR) and its downstream ribosomal phosphorylated RPS6KB1 (p-RPS6KB1) in NSCLC patients. We also analyzed p-mTOR/p-RPS6KB1 protein expression in 45 fresh NSCLC tissues using Western blotting. Results: The expression level of p-mTOR and p-RPS6KB1 was significantly higher in NSCLC tumor specimens than that in adjacent noncancerous normal lung tissues (P<0.01). p-mTOR expression correlated with p-RPS6KB1. Furthermore, high expression level of p-mTOR or p-RPS6KB1 in NSCLC was associated with a shorter overall survival (both P<0.01). Multivariate analysis indicated high level of p-mTOR expression was an independent prognostic factor (HR=2.642, 95%CI 1.157-4.904, p=0.002). Conclusions: p-mTOR and p-RPS6KB1 could be useful prognostic markers for NSCLC.

• Food Science and Biotechnology
• /
• 제17권5호
• /
• pp.1047-1051
• /
• 2008

Overexpression of HER2 in breast cancer cells is considered to induce the expression of acetyl-CoA carboxylase $\alpha$ (ACACA) and fatty acid synthase (FASN) through activation of mammalian target of rapamycin (mTOR) signaling pathway. Resveratrol, a red wine polyphenol, has been shown to induce apoptosis in several cancers by interfering in several signaling pathways. Present study elucidated the mechanism by which resveratrol downregulates ACACA and FASN in breast cancer cells. Resveratrol activated AMP-activated protein kinase (AMPK) and downregulated mTOR in BT-474 cells. These effects of resveratrol were mimicked by AICAR, an AMPK activator, and exogenously expressed constitutively active AMPK, while they were abolished by a dominant-negative mutant of AMPK. The downregulation of mTOR was not accompanied with changes in Akt, the upstream regulator of mTOR. These findings indicate that the downregulation of ACACA and FASN by resveratrol is mediated by the downregulation of mTOR signaling pathway via activation of AMPK.

• 한국동물생명공학회지
• /
• 제36권3호
• /
• pp.137-144
• /
• 2021

In this study, to analyze whether artificial regulation of apoptosis in the development of somatic cells can affect the stable growth and development of cells, 20 alpha-hydroxysteroid dehydrogenase (20α-HSD) and rapamycin were treated to induce apoptosis and autophagy in the both skin and muscle cells. Respectively, and 3-methyladenine was supplemented to inhibit cell death. Our results show that stimulation with rapamycin activated autophagy in both types of cells, but increased apoptosis more than autophagy in the case of skin cells. These results indicate that there was a difference in the expression of survival factors and cell development depending on the type of cell. In particular, in the expression of autophagy-related gene (MAP1LC3A) was higher than that of Casp-3, an apoptosis factor. Furthermore, cell development was the highest in all cell groups cultured by artificially inducing autophagy, however the lowest in the apoptosis-inhibited group. Especially, the noteworthy result of this study was that when apoptosis was induced using 20α-HSD, it was possible to induce apoptosis in both skin and muscle cells. Therefore, the main point of this study is that apoptosis induced during cell culture plays a pivotal role in cell remodeling.