Thapsigargin mechanism of action

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Cell Communication and Signaling volume 18 , Article number: 12 Cite this article. Metrics details. Cell death triggered by unmitigated endoplasmic reticulum ER stress plays an important role in physiology and disease, but the death-inducing signaling mechanisms are incompletely understood. To gain more insight into these mechanisms, the ER stressor thapsigargin Tg is an instrumental experimental tool. Additionally, Tg forms the basis for analog prodrugs designed for cell killing in targeted cancer therapy. Tg induces apoptosis via the unfolded protein response UPR , but how apoptosis is initiated, and how individual effects of the various UPR components are integrated, is unclear. Furthermore, the role of autophagy and autophagy-related ATG proteins remains elusive.

Thapsigargin mechanism of action

Federal government websites often end in. The site is secure. A sesquiterpene lactone, thapsigargin, is a phytochemical found in the roots and fruits of Mediterranean plants from Thapsia L. This biological activity encouraged studies on the use of thapsigargin as a novel antineoplastic agent, which were, however, hampered due to high toxicity of this compound to normal cells. In this review, we summarized the recent knowledge on the biological activity and molecular mechanisms of thapsigargin action and advances in the synthesis of less-toxic thapsigargin derivatives that are being developed as novel anticancer drugs. The skin-irritating properties, as well as the medical use of this plant, were known already in ancient times. The resin from the roots and fruits of T. The skin irritating component, named Tg, was isolated from T. The structural complexity of this carbon skeleton was challenging for organic chemists [ 2 ]. The first total synthesis of Tg from S -carvone, achieved in 42 steps with 0. Christensen and co-workers described a concise synthesis of Tg from nortribolide in [ 8 ].

On the other hand, Linder et al. The positions of molecular mass markers are indicated to the left of the blots.

Thapsigargin raises cytosolic intracellular calcium concentration by blocking the ability of the cell to pump calcium into the sarcoplasmic and endoplasmic reticula. Store-depletion can secondarily activate plasma membrane calcium channels , allowing an influx of calcium into the cytosol. Depletion of ER calcium stores leads to ER stress and activation of the unfolded protein response. Thapsigargin treatment and the resulting ER calcium depletion inhibits autophagy independent of the UPR. Thapsigargin is useful in experimentation examining the impacts of increasing cytosolic calcium concentrations and ER calcium depletion.

Cell Communication and Signaling volume 18 , Article number: 12 Cite this article. Metrics details. Cell death triggered by unmitigated endoplasmic reticulum ER stress plays an important role in physiology and disease, but the death-inducing signaling mechanisms are incompletely understood. To gain more insight into these mechanisms, the ER stressor thapsigargin Tg is an instrumental experimental tool. Additionally, Tg forms the basis for analog prodrugs designed for cell killing in targeted cancer therapy. Tg induces apoptosis via the unfolded protein response UPR , but how apoptosis is initiated, and how individual effects of the various UPR components are integrated, is unclear. Furthermore, the role of autophagy and autophagy-related ATG proteins remains elusive. To systematically address these key questions, we analyzed the effects of Tg and therapeutically relevant Tg analogs in two human cancer cell lines of different origin LNCaP prostate- and HCT colon cancer cells , using RNAi and inhibitory drugs to target death receptors, UPR components and ATG proteins, in combination with measurements of cell death by fluorescence imaging and propidium iodide staining, as well as real-time RT-PCR and western blotting to monitor caspase activity, expression of ATG proteins, UPR components, and downstream ER stress signaling. In both cell lines, Tg-induced cell death depended on death receptor 5 and caspase

Thapsigargin mechanism of action

Thapsigargin, the first representative of the hexaoxygenated guaianolides, was isolated 40 years ago in order to understand the skin-irritant principles of the resin of the umbelliferous plant Thapsia garganica. Thapsigargin has become a tool for investigation of the importance of SERCA in intracellular calcium homeostasis. In addition, complex formation of thapsigargin with SERCA has enabled crystallization and structure determination of calcium-free states by X-ray crystallography. Development of protocols for selective transformation of thapsigargin disclosed the chemistry and facilitated total synthesis of the molecule. Conversion of trilobolide into thapsigargin offered an economically feasible sustainable source of thapsigargin, which enables a future drug production. Principles for prodrug development were used by conjugating a payload derived from thapsigargin with a hydrophilic peptide selectively cleaved by proteases in the tumor. Mipsagargin was developed in order to obtain a drug for treatment of cancer diseases characterized by the presence of prostate specific membrane antigen PSMA in the neovascular tissue of the tumors. Even though mipsagargin showed interesting clinical effects the results did not encourage funding and consequently the attempt to register the drug has been abandoned. In spite of this disappointing fact, the research performed to develop the drug has resulted in important scientific discoveries concerning the chemistry, biosynthesis and biochemistry of sesquiterpene lactones, the mechanism of action of ATPases including SERCA, mechanisms for cell death caused by the unfolded protein response, and the use of prodrugs for cancer-targeting cytotoxins.

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Ron D, Walter P. Brown M. Iurlaro R, Munoz-Pinedo C. If the cell fails to restore this balance, the resulting chronic ER stress and persistent UPR signaling leads to cell death [ 1 ]. Hence, inducing cell death via ER stress and UPR might be a promising therapeutic strategy for killing cancer cells [ 38 ]. Mechanistic investigations of the cytotoxic actions of Tg can thus be expected to have important value not only for our understanding of UPR-induced cell death but also for our understanding and potential to optimize the therapeutic use of Tg prodrugs. Accepted : 16 December Molecular Mechanism of Tg Action 2. Apoptosis via DR5 and caspase 8. However, this view has been challenged by reports that indicate a suppressive role of calcineurin and calpains on caspase activation and cell death 35 , — Cancer 14 , — [ PubMed ] [ Google Scholar ]. Deng X. The involvement of JNK signaling pathway in Tg-mediated ER stress apoptosis was confirmed in several cancer cell lines and in the in vivo models [ 39 , 44 , 48 ]. Roti G. Andrews S.

Thapsigargin, the first representative of the hexaoxygenated guaianolides, was isolated 40 years ago in order to understand the skin-irritant principles of the resin of the umbelliferous plant Thapsia garganica. Thapsigargin has become a tool for investigation of the importance of SERCA in intracellular calcium homeostasis. In addition, complex formation of thapsigargin with SERCA has enabled crystallization and structure determination of calcium-free states by X-ray crystallography.

CAS Number. Roti et al. Cell death was assessed by live-cell fluorescence imaging of propidium iodide-stained cells as previously described [ 10 , 62 ]. Single points represent individual measurements mean values from triplicate wells , and each experiment is indicated with differently colored points. Sci Transl Med. Autophagy is activated for cell survival after endoplasmic reticulum stress. Contact us General enquiries: journalsubmissions springernature. In a and c , relative mRNA levels are shown normalized to the DMSO control-treated condition set to 1 and indicated by the dotted line in the graphs , i. Molecular requirements for cell death induction by therapy-relevant Tg analogs were identical to those observed with Tg. Additionally, Tg forms the basis for analog prodrugs designed for cell killing in targeted cancer therapy. For example, in a previous study, it was shown that, although Tg-induced death of renal cells was unaffected by calpain inhibition, calpains were important for cell death induced by reactive chemical toxicants Recent studies have however demonstrated that caution must be exerted with regard to drawing strong conclusions from death receptor knockout studies [ 21 , 76 ].