unfolded protein response

Prostate apoptosis response protein PAR-4 (2-7) [Homo sapiens] is a peptide with the sequence H2N-Ala-Thr-Gly-Gly-Tyr-Arg-OH, MW= 623.66.

Thapsigargin is a natural product, an inhibitor of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) and an endoplasmic reticulum stress inducer. Thapsigargin increases cytoplasmic calcium concentration by blocking the ability of cells to pump calcium into the sarcoplasmic and endoplasmic reticulum.

BOLD-100 free base (NKP-1339; IT-139), a ruthenium-based anticancer agent, inhibits stress-induced GRP78 upregulation, thus disrupting endoplasmic reticulum (ER) homeostasis. This action induces ER stress and unfolded protein response (UPR), interfering with the intricate relationship between ER-stress response, lysosome dynamics, and autophagy execution.

RA-9 is a potent and selective proteasome-associated inhibitor of deubiquitinating enzymes (DUBs), with favorable toxicity profile and anticancer activity. RA-9 selectively induces apoptosis in ovarian cancer cell lines.

Nemorosone is a polycyclic polyprenylated acylphloroglucinol (PPAP) originally isolated from C. rosea that has antiproliferative properties.1 Nemorosone inhibits growth of NB69, Kelly, SK-N-AS, and LAN-1 neuroblastoma cells (IC50s = 3.1-6.3 μM), including several drug-resistant clones, but not MRC-5 human embryonic fibroblasts (IC50 = >40 μM).2 It increases DNA fragmentation in LAN-1 cells in a dose-dependent manner, and decreases N-Myc protein levels and phosphorylation of ERK1/2 by MEK1/2. Nemorosone also inhibits growth of Capan-1, AsPC-1, and MIA-PaCa-2 pancreatic cancer cells (IC50s = 4.5-5.0 μM following a 72-hour treatment) but not human dermal and foreskin fibroblasts (IC50s = >35 μM).1 It induces apoptosis, abolishes the mitochondrial membrane potential, and increases cytosolic calcium concentration in pancreatic cancer cells in a dose-dependent manner. Nemorosone activates the caspase cascade in a dose-dependent manner and inhibits cell cycle progression, increasing the proportion of cells in the G0/G1 phase, in both neuroblastoma and pancreatic cancer cells.1,2 Nemorosone (50 mg/kg, i.p., per day) also reduces tumor growth in an MIA-PaCa-2 mouse xenograft model.3References1. Holtrup, F., Bauer, A., Fellenberg, K., et al. Microarray analysis of nemorosone-induced cytotoxic effects on pancreatic cancer cells reveals activation of the unfolded protein response (UPR). Br. J. Pharmacol. 162(5), 1045-1059 (2011).2. Díaz-Carballo, D., Malak, S., Bardenheuer, W., et al. Cytotoxic activity of nemorosone in neuroblastoma cells. J. Cell. Mol. Med. 12(6B), 2598-2608 (2008).3. Wold, R.J., Hilger, R.A., Hoheisel, J.D., et al. In vivo activity and pharmacokinetics of nemorosone on pancreatic cancer xenografts. PLoS One 8(9), e74555 (2013). Nemorosone is a polycyclic polyprenylated acylphloroglucinol (PPAP) originally isolated from C. rosea that has antiproliferative properties.1 Nemorosone inhibits growth of NB69, Kelly, SK-N-AS, and LAN-1 neuroblastoma cells (IC50s = 3.1-6.3 μM), including several drug-resistant clones, but not MRC-5 human embryonic fibroblasts (IC50 = >40 μM).2 It increases DNA fragmentation in LAN-1 cells in a dose-dependent manner, and decreases N-Myc protein levels and phosphorylation of ERK1/2 by MEK1/2. Nemorosone also inhibits growth of Capan-1, AsPC-1, and MIA-PaCa-2 pancreatic cancer cells (IC50s = 4.5-5.0 μM following a 72-hour treatment) but not human dermal and foreskin fibroblasts (IC50s = >35 μM).1 It induces apoptosis, abolishes the mitochondrial membrane potential, and increases cytosolic calcium concentration in pancreatic cancer cells in a dose-dependent manner. Nemorosone activates the caspase cascade in a dose-dependent manner and inhibits cell cycle progression, increasing the proportion of cells in the G0/G1 phase, in both neuroblastoma and pancreatic cancer cells.1,2 Nemorosone (50 mg/kg, i.p., per day) also reduces tumor growth in an MIA-PaCa-2 mouse xenograft model.3 References1. Holtrup, F., Bauer, A., Fellenberg, K., et al. Microarray analysis of nemorosone-induced cytotoxic effects on pancreatic cancer cells reveals activation of the unfolded protein response (UPR). Br. J. Pharmacol. 162(5), 1045-1059 (2011).2. Díaz-Carballo, D., Malak, S., Bardenheuer, W., et al. Cytotoxic activity of nemorosone in neuroblastoma cells. J. Cell. Mol. Med. 12(6B), 2598-2608 (2008).3. Wold, R.J., Hilger, R.A., Hoheisel, J.D., et al. In vivo activity and pharmacokinetics of nemorosone on pancreatic cancer xenografts. PLoS One 8(9), e74555 (2013).

BHPI is a potent ERα inhibitor that blocks nuclear estrogen–ERα-regulated gene expression effectively. It triggers sustained ERα-dependent activation of the endoplasmic reticulum (EnR) stress sensor, notably the unfolded protein response (UPR), and consistently inhibits protein synthesis. With an IC50 value targeting ERα, BHPI's mechanism involves the rapid hyperactivation of PLCγ on the plasma membrane in ERα(+) cancer cells, which produces inositol 1,4,5-triphosphate (IP3). This, in turn, opens EnR IP3R calcium channels, leading to a rapid depletion of EnR Ca(2+) stores. SIGNIFICANTLY, BHPI alters estrogen-ERα's usual effect of causing mild and transient UPR activation by inducing a severe and prolonged UPR activation, transforming the UPR from a protective to a toxic response.

CCI-006, a selective inhibitor and chemosensitizer for MLL-rearranged leukemia cells, disrupts mitochondrial respiration. This action leads to irreversible mitochondrial depolarization and triggers a pro-apoptotic unfolded protein response in specific MLL-r leukemia cells.

3,6-DMAD hydrochloride functions as an inhibitor for the IRE1α-XBP1 pathway within the unfolded protein response mechanism.

IRE1α kinase-IN-9 (compound 2) is a potent inhibitor of IRE-1α, demonstrating an average IC50 value of less than 0.1 μM. It is suitable for research into diseases linked to the unfolded protein response or regulated IRE1-dependent decay (RIDD) [1].

3,6-DMAD hydrochloride is an inhibitor of the unfolded protein response (IRE1α-XBP1) pathway.

IXA4 is a highly selective, nontoxic activator of IRE1/XBP1s and reduces APP secretion by activating IRE1. IXA4-stimulated IRE1 activation also enhanced pancreatic function.

Ceapin-A7, with an IC50 of 0.59 μM, selectively inhibits ATF6α signaling in response to ER stress. This compound is instrumental in investigating ATF6α's activation mechanism and its function in pathological conditions.

AA147 (ATF6-activator-147) is a small molecule endoplasmic reticulum (ER) proteostasis regulator. The selectively activates ATF6 arm of the unfolded protein response (UPR) .It acts as a prodrug that preferentially triggers ATF6 signaling through a mechanism involving localized metabolic activation and selective covalent modification of ER resident proteins that regulate ATF6 activity.

IRE1α kinase-IN-8, a benzoheterocyclecarboxaldehyde derivative, serves as a potent inhibitor of IRE-1α. This compound is utilized in research pertaining to diseases linked to the unfolded protein response and regulated IRE1-dependent decay (RIDD) [1].

Z36 is a novel Bcl-xL inhibitor, upregulating the expression levels of FAM134B, LC3, and Atg9, inducing autophagy along with autophagic cell death, resulting in ER stress and the unfolded protein response (UPR).

ErSO is a selective activator of anticipatory unfolded protein response (UPR) via ERα receptor. ErSO can be used in studies about anti-cancer.

ML291 is a sufonamidebenzamide compound that induces the unfolded protein response (UPR) and overwhelms the adaptive capacity of UPR, resulting in apoptosis in various solid cancer models. It activates the PERK/eIF2a/CHOP apoptotic pathway of UPR and reduces leukemic cell burden [1].

Azoramide, a small-molecule modulator, has the antidiabetic activity of unfolded protein response.

(±)-ErSO is the racemic form of ErSO. ErSO is a selective anticipatory activator of the unfolded protein response (a-UPR).

UPR-IN-17# is an effective pan-inhibitor of the unfolded protein response.

ErSO-DFP is an expected activator of the unfolded protein response (a-UPR). erSO-DFP improves selectivity for oestrogen receptor alpha+ (ERα+) cancer cells with higher selectivity than ErSO. erSO-DFP has anti-tumour effects and significantly eliminates MCF-7 tumours in a mouse model.