Diterpenoid Vinigrol activates ATF4/DDIT3-mediated PERK/eIF2α arm of unfolded protein response to drive breast cancer cell death

AbstractVinigrol is a natural diterpenoid with unprecedented chemical structure, driving great efforts into its total synthesis and the chemical analogs in the past decades. Despite its pharmacological efficacies reported on anti-hypertension and anti-clot, comprehensive functional investigations on Vinigrol and the underlying molecular mechanisms are entirely missing. In this study, we carried out a complete functional prediction of Vinigrol using a transcriptome-based strategy, Connectivity Map, and identified “anti-cancer” as the most prominent biofunction ahead of anti-hypertension and anti-depression/psychosis. A broad cytotoxicity was subsequently confirmed on multiple cancer types. Further mechanistic investigation on MCF7 cells revealed that its anti-cancer effect is mainly through activating PERK/eIF2α arm of unfolded protein response (UPR) and subsequent upregulation of p53/p21 to halt the cell cycle. The other two branches of UPR, IRE1α and ATF6, are functionally irrelevant to Vinigrol-induced cell death. CRISPR/Cas9-based gene activation, repression, and knockout systems identified essential contribution of ATF4/DDIT3 not ATF6 to the death process. This study unraveled a broad anti-cancer function of Vinigrol and its underlying targets and regulatory mechanisms, and also paved the way for further inspection on the structure-efficacy relationship of the whole compound family, making them a novel cluster of chemical hits for cancer therapy.

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Downregulation of miR-17-92 cluster by PERK fine-tunes unfolded protein response mediated apoptosis

10.1101/2020.10.26.354894 ◽

2020 ◽

Author(s):

Danielle E. Read ◽

Ananya Gupta ◽

Karen Cawley ◽

Laura Fontana ◽

Patrizia Agostinis ◽

...

Keyword(s):

Cell Death ◽

Er Stress ◽

Unfolded Protein Response ◽

Molecular Mechanisms ◽

Ectopic Expression ◽

Proximal Region ◽

Dependent Manner ◽

Unfolded Protein ◽

Promoter Deletion Analysis ◽

Protein Response

AbstractAn important event in the unfolded protein response (UPR) is the activation of the endoplasmic reticulum kinase PERK (EIF2AK3). The PERK signalling branch first mediates a prosurvival response, which switches into a proapoptotic response upon prolonged ER stress. However, the molecular mechanisms of PERK-mediated cell death are not well understood. Here we show that expression of the primary miR-17-92 transcript and mature miRNAs belonging to miR-17-92 cluster is decreased during UPR. We found that activity of miR-17-92 promoter reporter was reduced during UPR in a PERK-dependent manner. We show that activity of miR-17-92 promoter is repressed by ectopic expression of ATF4 and NRF2. The promoter deletion analysis and ChIP assays mapped the region responding to UPR-mediated repression to site in the proximal region of the miR-17-92 promoter. Hypericin-mediated photo-oxidative ER damage reduced the expression of miRNAs belonging to miR-17-92 cluster in wild-type but not in PERK-deficient cells. Importantly, ER stress-induced apoptosis was inhibited upon miR-17-92 overexpression in SH-SY5Y and H9c2 cells. Our results reveal a novel function for NRF2, where repression of miR-17-92 cluster by NRF2 plays an important role in ER stress-mediated apoptosis. The data presented here provides mechanistic details how sustained PERK signalling via NRF2 mediated repression of miR-17-92 cluster can potentiate cell death.

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Downregulation of miR-17-92 Cluster by PERK Fine-Tunes Unfolded Protein Response Mediated Apoptosis

Life ◽

10.3390/life11010030 ◽

2021 ◽

Vol 11 (1) ◽

pp. 30

Author(s):

Danielle E. Read ◽

Ananya Gupta ◽

Karen Cawley ◽

Laura Fontana ◽

Patrizia Agostinis ◽

...

Keyword(s):

Cell Death ◽

Er Stress ◽

Unfolded Protein Response ◽

Molecular Mechanisms ◽

Ectopic Expression ◽

Proximal Region ◽

Dependent Manner ◽

Unfolded Protein ◽

Promoter Deletion Analysis ◽

Protein Response

An important event in the unfolded protein response (UPR) is activation of the endoplasmic reticulum (ER) kinase PERK. The PERK signalling branch initially mediates a prosurvival response, which progresses to a proapoptotic response upon prolonged ER stress. However, the molecular mechanisms of PERK-mediated cell death are not well understood. Here we show that expression of the primary miR-17-92 transcript and mature miRNAs belonging to the miR-17-92 cluster are decreased during UPR. We found that miR-17-92 promoter reporter activity was reduced during UPR in a PERK-dependent manner. Furthermore, we show that activity of the miR-17-92 promoter is repressed by ectopic expression of ATF4 and NRF2. Promoter deletion analysis mapped the region responding to UPR-mediated repression to a site in the proximal region of the miR-17-92 promoter. Hypericin-mediated photo-oxidative ER damage reduced the expression of miRNAs belonging to the miR-17-92 cluster in wild-type but not in PERK-deficient cells. Importantly, ER stress-induced apoptosis was inhibited upon miR-17-92 overexpression in SH-SY5Y and H9c2 cells. Our results reveal a novel function for ATF4 and NRF2, where repression of the miR-17-92 cluster plays an important role in ER stress-mediated apoptosis. Mechanistic details are provided for the potentiation of cell death via sustained PERK signalling mediated repression of the miR-17-92 cluster.

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Unfolded protein response triggers differential apoptotic mechanisms in ovaries and early embryos exposed to maternal type 1 diabetes

Scientific Reports ◽

10.1038/s41598-021-92093-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aslı Okan ◽

Necdet Demir ◽

Berna Sozen

Keyword(s):

Embryonic Development ◽

Er Stress ◽

Unfolded Protein Response ◽

Molecular Mechanisms ◽

Early Embryonic Development ◽

Unfolded Protein ◽

Caspase 12 ◽

Early Embryos ◽

Protein Response

AbstractDiabetes mellitus (DM) has profound effects on the female mammalian reproductive system, and early embryonic development, reducing female reproductive outcomes and inducing developmental programming in utero. However, the underlying cellular and molecular mechanisms remain poorly defined. Accumulating evidence implicates endoplasmic reticulum (ER)-stress with maternal DM associated pathophysiology. Yet the direct pathologies and causal events leading to ovarian dysfunction and altered early embryonic development have not been determined. Here, using an in vivo mouse model of Type 1 DM and in vitro hyperglycaemia-exposure, we demonstrate the activation of ER-stress within adult ovarian tissue and pre-implantation embryos. In diabetic ovaries, we show that the unfolded protein response (UPR) triggers an apoptotic cascade by the co-activation of Caspase 12 and Cleaved Caspase 3 transducers. Whereas DM-exposed early embryos display differential ER-associated responses; by activating Chop in within embryonic precursors and Caspase 12 within placental precursors. Our results offer new insights for understanding the pathological effects of DM on mammalian ovarian function and early embryo development, providing new evidence of its mechanistic link with ER-stress in mice.

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Unfolded protein response and cell death after depletion of brefeldin A-inhibited guanine nucleotide-exchange protein GBF1

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0712224105 ◽

2008 ◽

Vol 105 (8) ◽

pp. 2877-2882 ◽

Cited By ~ 68

Author(s):

C. Citterio ◽

A. Vichi ◽

G. Pacheco-Rodriguez ◽

A. M. Aponte ◽

J. Moss ◽

...

Keyword(s):

Cell Death ◽

Unfolded Protein Response ◽

Brefeldin A ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Unfolded Protein ◽

Guanine Nucleotide Exchange ◽

Protein Response ◽

Exchange Protein

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Oxidative stress-triggered unfolded protein response is upstream of intrinsic cell death evoked by parkinsonian mimetics

Journal of Neurochemistry ◽

10.1111/j.1471-4159.2006.04025.x ◽

2006 ◽

Vol 99 (1) ◽

pp. 54-69 ◽

Cited By ~ 76

Author(s):

William A. Holtz ◽

Jay M. Turetzky ◽

Yuh-Jiin I. Jong ◽

Karen L. O'Malley

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Unfolded Protein Response ◽

Unfolded Protein ◽

Protein Response

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The Unfolded Protein Response in Immunogenic Cell Death and Cancer Immunotherapy

Trends in Cancer ◽

10.1016/j.trecan.2017.07.002 ◽

2017 ◽

Vol 3 (9) ◽

pp. 643-658 ◽

Cited By ~ 48

Author(s):

Nicole Rufo ◽

Abhishek D. Garg ◽

Patrizia Agostinis

Keyword(s):

Cell Death ◽

Unfolded Protein Response ◽

Cancer Immunotherapy ◽

Immunogenic Cell Death ◽

Unfolded Protein ◽

The Unfolded Protein Response ◽

Protein Response

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ScreeningMycobacterium tuberculosisSecreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector

mSphere ◽

10.1128/msphere.00354-19 ◽

2019 ◽

Vol 4 (3) ◽

Cited By ~ 2

Author(s):

Chelsea E. Stamm ◽

Breanna L. Pasko ◽

Sujittra Chaisavaneeyakorn ◽

Luis H. Franco ◽

Vidhya R. Nair ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Mycobacterium Tuberculosis ◽

Unfolded Protein Response ◽

Molecular Mechanisms ◽

Membrane Binding ◽

Host Cells ◽

Secreted Proteins ◽

Content Type ◽

Unfolded Protein ◽

Protein Response

ABSTRACTMycobacterium tuberculosis(Mtb), the causative agent of tuberculosis, is one of the most successful human pathogens. One reason for its success is that Mtb can reside within host macrophages, a cell type that normally functions to phagocytose and destroy infectious bacteria. However, Mtb is able to evade macrophage defenses in order to survive for prolonged periods of time. Many intracellular pathogens secrete virulence factors targeting host membranes and organelles to remodel their intracellular environmental niche. We hypothesized that Mtb secreted proteins that target host membranes are vital for Mtb to adapt to and manipulate the host environment for survival. Thus, we characterized 200 secreted proteins from Mtb for their ability to associate with eukaryotic membranes using a unique temperature-sensitive yeast screen and to manipulate host trafficking pathways using a modified inducible secretion screen. We identified five Mtb secreted proteins that both associated with eukaryotic membranes and altered the host secretory pathway. One of these secreted proteins, Mpt64, localized to the endoplasmic reticulum during Mtb infection of murine and human macrophages and impaired the unfolded protein response in macrophages. These data highlight the importance of secreted proteins in Mtb pathogenesis and provide a basis for further investigation into their molecular mechanisms.IMPORTANCEAdvances have been made to identify secreted proteins ofMycobacterium tuberculosisduring animal infections. These data, combined with transposon screens identifying genes important forM. tuberculosisvirulence, have generated a vast resource of potentialM. tuberculosisvirulence proteins. However, the function of many of these proteins inM. tuberculosispathogenesis remains elusive. We have integrated three cell biological screens to characterize nearly 200M. tuberculosissecreted proteins for eukaryotic membrane binding, host subcellular localization, and interactions with host vesicular trafficking. In addition, we observed the localization of one secreted protein, Mpt64, to the endoplasmic reticulum (ER) duringM. tuberculosisinfection of macrophages. Interestingly, although Mpt64 is exported by the Sec pathway, its delivery into host cells was dependent upon the action of the type VII secretion system. Finally, we observed that Mpt64 impairs the ER-mediated unfolded protein response in macrophages.

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