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The xanthones are a diverse class of natural products that can be extracted from plants, fungi, lichen, and invertebrates. They have a wide range of biological activities, including antitumor and antimicrobial activity.

DMXAA, a synthetic derivative of xanthone, attracted particular interest in the 2000s because it disrupts tumor blood supply in mice. In 2008 it entered Phase III clinical trials for non-small cell lung cancer. It failed to show benefit in humans.

Recently, Shih et al. investigated the failure of DMXAA to translate across species. In mice, DMXAA activates the STING (stimulator-of-interferon-genes) protein, which leads to an immune response against tumors. DMXAA does not activate human STING.

The binding pockets of human and mouse STING are identical. So what causes the difference in DMXAA effectiveness? Shih et al. used molecular dynamics, a computational method that simulates the movements of molecules. When they simulated the binding of DMXAA to human STING and mouse STING, they found that the lid of mouse STING remains closed, preventing bound DMXAA from leaving. In human STING, the DMXAA leaves. A peptide residue in the STING lid region is responsible for the difference.

This work may aid in the rational design of a STING activator, but the researchers conclude that the design of such a drug would be challenging.

D509921 DMXAA

STING Activators

Shih AY, Damm-Ganamet KL, Mirzadegan T. Dynamic Structural Differences between Human and Mouse STING Lead to Differing Sensitivity to DMXAA. 2018. Biophysical Journal. DOI: 114:32-39.

MELK (maternal embryonic leucine zipper kinase) signals cell division and may play a role in several kinds of cancer. In 2012, researchers screened for inhibitors of MELK and found a substance that they named OTSSP167. OTSSP167 shows promise as a chemotherapy drug.

Bone disease is a top cause of morbidity for multiple myeloma patients. Bone lesions cause bone pain, bone breakdown, and encourage further tumor growth. Even when chemotheraphy causes tumor remission, the bone lesions don’t heal. Bisphosphonates, the current standard of care, come with serious side effects.

Researchers Muller and Bolomsky investigated OTSSP167’s potential to treat multiple myeloma. In 2018, Bolomsky et al. found that OTSSP167 reduced tumor load in a multiple myeloma mouse model. As predicted, it worked by inhibiting MELK. The researchers also found that OTSSP167 reduced multiple myeloma bone disease, even at doses that were too low to inhibit tumor growth. They followed up on their findings in another 2018 paper.

In the follow-up, Muller et al. dosed bone cell cultures and multiple myeloma mice with OTSSP167. They found that OTSSP167 inhibits the growth and function of osteoclasts, cells that reabsorb bone, and stimulates osteoblasts, cells that produce bone. The mice dosed with OTSSP167 had fewer bone lesions and better bone volume than controls.

Muller et al. conclude that OTSSP167 has the potential to treat multiple myeloma tumors and to reduce bone lesions.

O783743 OTSSP167 Hydrochloride

Chung S, Suzuki H, Miyamoto T, et al. Development of an orally-administrative MELK-targeting inhibitor that suppresses the growth of various types of human cancer. Oncotarget. 2012 3(12):1629–1640. doi:10.18632/oncotarget.790

Muller J, Bolomsky A, Dubois S, Duray E, Stangelberger K, Plougonven E, Lejeune M, Léonard A, Marty C, Hempel U, Baron F, Beguin Y, Cohen-Solal M, Ludwig H, Heusschen R, Caers J. Maternal embryonic leucine zipper kinase inhibitor OTSSP167 has preclinical activity in multiple myeloma bone disease. Haematologica. 2018 Vol 103(8):1359-1368.

Bolomsky A, Heusschen R, Schlangen K, et al. Maternal embryonic leucine zipper kinase is a novel target for proliferation- associated high-risk myeloma. Haematologica. 2018 103(2):325-335.

Rose bengal and fluorescein can stain damaged conjunctival and corneal tissue in the eye. They play an important role in ophthalmology to diagnose dry eye and eye surface damage. The mechanism these stains use to stain damaged cells and not healthy ones is not understood.

Dynasore is a small molecule that inhibits dynamin. Dynamin is essential for endocytosis in eukaryotic cells, so dynasore inhibits endocytosis. Dynasore is used as a cell biology research tool.

Recently, Webster et al. proposed a mechanism for how rose bengal and fluorescein work. Sublethal cell damage causes the cell to repair itself by remodeling its plasma membrane. While remodeling the plasma membrane, the cell might take up stain via endocytosis. They tested their hypothesis by applying oxidative stress to monolayer cultures of human corneal epithelial cells. The oxidative stress caused an increase in both stain uptake and endocytosis. Then they applied the endocytosis inhibitors chlorpromazine hydrochloride, genistein, Dynasore hydrate, and Dyngo-4a (a Dynasore derivative). Stain uptake was blocked.

However, when they repeated the experiment in whole eye tissue harvested from mice, oxidative stress increased stain uptake, but did not increase endocytosis. Most of the endocytosis inhibitors did not block stain uptake. Dynasore and Dyngo-4a did.

If eye cell damage increased stain uptake but not endocytosis, endocytosis must not be the mechanism for cell uptake. Then why did two of the endocytosis inhibitors, Dynasore and its derivative, inhibit stain uptake if endocytosis was not involved?

Webster et al. performed cytotoxicity and Western blotting assays and concluded that Dynasore and Dyngo-4a prevented oxidative damage to the cells. The results have implications for the field of ophthalmology. Dynasore and Dyngo-4a may have therapeutic potential.

In 2008, Yu et al. identified a compound that dorsalizes structures in growing zebrafish embryos, which they named dorsomorphin. This compound inhibits the bone morphogenetic protein (BMP) signaling pathway, which plays an important role in development and cell differentiation.

Recently, Valizadeh-Arshad et al. hypothesized that small molecules like dorsomorphin could be used to promote human embryonic stem cells to differentiate into motor neurons. One of the goals of regenerative medicine is to produce tissues such as neurons from stem cells, to heal nerve damage that will not heal on its own. Currently, coaxing embryonic stem cells to differentiate into motor neurons is expensive and inefficient.

The researchers modified an existing motor neuron differentiation protocol to include a cocktail of small molecules that have shown promise in previous studies: all-trans retinoic acid, dorsomorphin, A8301, and XAV939. They cultured the embryonic stem cells on plates, and exposed the cells to the small molecules as well as established differentiation factors.

They then used flow cytometry and immunofluorescence staining on the cells to test for expression of genes associated with neurons, such as NESTIN, PAX6, and MAP2. The cells expressed these marker genes with efficiencies greater than 50%. The cells showed voltage-gated currents in a patch-clamp experiment, suggesting the presence of both K+ and Ca++/Na+ channels. However, the cells were unable to generate more than single action potentials. More research needs to be done before this cell differentiation method can produce mature motor neurons.

D582703 Dorsomorphin

D582705 Dorsomorphin Dihydrochloride

R1877 all-trans-retinol, ≥98%

Valizadeh-Arshad Z, Shahbazi E, Hashemizadeh S, Moradmand A, Jangkhah M, Kiani S. In Vitro Differentiation of Neural-Like Cells from Human Embryonic Stem Cells by A Combination of Dorsomorphin, XAV939, and A8301. Cell J. 2018 19:4. doi: 10.1038/nbt1201-1129.

Yu PB, Hong CC, Sachidanandan C, et al. Dorsomorphin inhibits BMP signals required for embryogenesis and iron metabolism. Nat Chem Biol. 2007;4(1):33–41. doi:10.1038/nchembio.2007.54.

When food or feed crops are stored in hot, humid conditions, fungi that live on them can produce mycotoxins that threaten human and animal health. Even minute quantities of mycotoxins can cause disease. For example, aflatoxins are potent carcinogens, ochratoxin has been implicated in kidney disease, and zearalenone is an estrogen mimic that can cause infertility or miscarriage. Deoxynivalenol is a threat to livestock because when it is present in feed, the livestock fail to gain weight.

The European Commission sets strict maximum limits on mycotoxin concentrations in crops used for food or feed in Europe. However, the regulations never mention insects or insect feed. Edible insects are a promising emerging crop because they produce protein more efficiently and with less pollution than larger livestock animals. The European legal limit of mycotoxins in edible insects is not clear.

Recently, Camenzuli et al. set out to clarify the safety of mycotoxin exposure in edible insects. They studied two promising food insect species, the lesser mealworm (Alphitobius diaperinus) and the black soldier fly (Hermetia illucens). The researchers spiked larvae feed with aflatoxin B1, deoxynivalenol, ochratoxin A and zearalenone at 1, 10 and 25 times the limit allowed for livestock feed. They found no effect on the survival or weight gain for either species, except for lesser mealworms given the highest level of ochratoxin A, which gained less weight.

Camenzuli et al. also tested for accumulation of the mycotoxins in the larvae. They could not detect any of the mycotoxins in the lesser mealworms, even when given the highest doses. In the black soldier fly, they could not detect mycotoxins when larvae were given low doses, and found only minute quantities of deoxynivalenol, zearalenone, and ochratoxin at the highest doses.

The metabolites of mycotoxins might also pose a threat to human or livestock health. For example, the zearalenone metabolite α-zearalenol is a more potent estrogen mimic than zearalenone itself. To account for this, the researchers tested for the accumulation of aflatoxicol, aflatoxin P1, aflatoxin Q1, aflatoxin M1, 3-acetyl-DON, 15-acetyl-DON, DON-3-glycoside, and α- and β-zearalenol in the larvae. None of the mycotoxin metabolites were detectable in the lesser mealworms. In the black soldier fly larvae, aflatoxin and deoxynivalenol metabolites were undetectable. Low concentrations of α- and β-zearalenol were found in the black soldier fly larvae at all doses.

Camenzuli et al. concluded that food source insects might be able to tolerate higher concentrations of mycotoxins in their feed than other livestock, but more research is needed.

Z1602 Zearalenone

Z161024 α-zearalenol

Z161025 β-zearalenol

Full list of available mycotoxins

Camenzuli L, Van Dam R, Rijk T, Andriessen R, Van Schelt J, Van der Fels-Klerx HJ. Tolerance and Excretion of the Mycotoxins Aflatoxin B1, Zearalenone, Deoxynivalenol, and Ochratoxin A by Alphitobius diaperinus and Hermetia illucens from Contaminated Substrates. Toxins 2018, 10, 91; doi:10.3390/toxins10020091

Palmatine is an isoquinoline alkaloid naturally found in plant species such as Corydalis and Phellodendron. It exhibits a wide array of biological effects, such as sedative, antidepressant, antioxidative, anticancer, and antacid activities. In a recent study by Chakravarthy, et al. at the University of Texas Health Science Center in San Antonio, Palmatine has shown potential as an agent for the clinical management of pancreatic cancer.

Advanced pancreatic ductal adenocarcinoma (PDAC) has a notoriously high mortality rate. Current therapies, primarily centered around gemcitabine treatment in combination with other agents, have shown modest success but are limited to select groups of patients.

Pancreatic stellate cells (PSCs) are considered to be the driver of pancreatic fibrosis and are activated by a number of factors, including inflammation. Once activated, PSCs are responsible for the expression of alpha smooth muscle actin and collagen 1 type 1 alpha 1 (COL1A1). Pancreatic cancer cells (PCCs) also activate PSCs. Inhibiting the growth of activated PSCs and PCCs with novel compounds has become one possible strategy for combating PDAC.

Palmatine is one such compound. Chakravarthy, et al. show that palmatine inhibits both the growth of PSCs and inhibits the sonic hedgehog pathway. By disrupting the interaction between PSCs and PCCs, palmatine treatment may be a viable method of clinical management of PDAC, either alone or in conjunction with a chemotherapy agents like gemcitabine.

LKT Labs offers palmatine and other chemotherapy agents like gemcitabine for research use.

P0245 Palmatine

G1745 Gemcitabine Hydrochloride

I6932 Irinotecan

O9201 Oxaliplatin

References:

Chakravarthy D, Munoz A, Su A, et al. Palmatine suppresses gluatmine-mediated interaction between pancreatic cancer and stellate cells through simultaneous inhibition of survivin and COL1A1.  Cancer Lett. 2018 Apr 10;419:103-115. doi: 10.1016/j.canlet.2018.01.057

Bee venom is a complex mixture of enzymes, polypeptides, amino acids, and sugars. Traditional Chinese medicine uses bee venom acupuncture to treat arthritis and pain. However, the components of bee venom are the subject of biomedical research for their potential painkiller, antithrombotic, and antibiotic properties. The polypeptide melittin makes up 40-60 percent of the dry weight of bee venom and causes the pain of bee stings. Apamin, which makes up 2-3 percent of bee venom dry weight, is a neurotoxin that inhibits Ca++ -activated K+ channels in the central nervous system. It is used in biomedical research to study how these channels work.

In South Korea, manufacturers put bee venom extracts into skin care products, citing the benefits of traditional medicine. Consumers who use these products have inadvertently found an antifungal effect.

Recently, Park et al. investigated the antifungal properties of bee venom. The experimenters prepared cultures of Trichophyton rubrum, the pathogen responsible for athlete’s foot and jock itch, on potato dextrose cornmeal agar plates. They exposed each culture to one of four different treatments: raw bee venom, a commercial bee-venom-based skincare product, apamin, or melittin. They let each T. rubrum culture grow for two weeks.

Every two days, the experimenters calculated the growth rate of each T. rubrum culture. They found that melittin and apamin do not inhibit T. rubrumgrowth, but raw bee venom and the skincare product do inhibit growth. They conclude that bee venom does have antifungal potential, but neither melittin nor apamin can inhibit fungus alone. Bee venom will need more investigation before it can see clinical use.

A6002 Apamin

M1744 Melittin

Park J, Kwon O, An HJ, Park KK. Antifungal Effects of Bee Venom Components on Trichophyton rubrum: A Novel Approach of Bee Venom Study for Possible Emerging Antifungal Agent. (2018). Annals of Dermatology 30:2. doi: 10.5021/ad.2018.30.2.202.

Valproic acid is an anticonvulsant drug that was first synthesized in 1882 and thought to have no biological activity. In 1962, Pierre Eymard discovered its anticonvulsant properties by accident when he used it as a carrier for other anticonvulsant drugs in a trial on rats. Today, valproic acid is on the World Health Organization list of essential medicines and a common treatment for epilepsy.

Valproic acid also has FDA approval for the treatment of bipolar disorder. Its mechanism of action is not fully understood. It may work by increasing levels of GABA in the brain or by inhibiting histone deacetylase and thereby altering brain gene expression. In 2018, Joshi et al. hypothesized that valproic acid and the mood stabilizer lithium alter the expression levels of synapsin, proteins expressed in neurons that regulate synapse function, including vesicle maintenance and neurotransmitter release.

The researchers dosed rats with lithium, valproic acid, or saline twice daily for two weeks. RNA was then extracted from the brain tissue of the rats, and real-time PCR was used to measure the synapsin expression level. Rats dosed with lithium or valproic acid showed increases in synapsin expression across several brain tissues. Specifically, synapsin IIa increased by about 25% in the hippocampus and prefrontal cortex, and synapsin IIb increased by 25-50% in the hippocampus and striatum. Both lithium- and valproic-acid-dosed rats saw these increases.

Valproic acid may work to treat epilepsy and bipolar disorder through the upregulation of synapsins. LKT Laboratories carries valproic acid as well as a number of anticonvulsant and antiepileptic molecules for research use.

V0148 Valproic Acid

C0270 Carbamazepine

O9210 Oxcarbazepine

Z5653 Zonisamide

Joshi H, Sharma R, Prashar S, Ho J, Thomson S, Mishra R. Differential Expression of Synapsin I and II upon Treatment by Lithium and Valproic Acid in Various Brain Regions. International Journal of Neuropsychopharmacology (2018) 21(6): 616–622.

Palbociclib is a chemotherapy drug used to treat advanced breast cancers. In a phase 3 clinical trial, a combination of palbociclib and fulvestrant more than doubled median progression-free survival time in women with ER+, HER- breast cancer compared to fulvestrant alone. Palbociclib received accelerated approval from the FDA in 2015 for ER+ breast cancers, and in 2017 was approved for the treatment of HER2- breast cancers.

The cyclin-dependent kinases CDK4 and CDK6 cause cells to pass from the G1 phase to the S phase and divide. Palbociclib works by selectively inhibiting these kinases.

Recently, Miettinen et al. argued that palbociclib’s remarkable effectiveness against breast cancer can not be explained by CDK4 and CDK6 inhibition alone. They used a method called cellular thermal shift assay to investigate other targets of palbociclib within the cell. This assay measures changes in the thermal stability of proteins in living cells, which can be used to determine which proteins are bound or modified by the drug of interest.

Miettinen et al. found that palbociclib targets the proteasome in a breast cancer cell line. Palbociclib activates the proteasome by preventing the suppressor protein ECM29 from binding to it. The authors speculate that tightly regulated proteasome activity is required for cell division, so palbociclib’s activation of the proteasome could be another way that it treats breast cancer.

Miettinen TP, Peltier J, Hartlova A, Gierlinski M, Jansen VM, Trost M, Bjorklund M. Thermal proteome profiling of breast cancer cells reveals proteasomal activation by CDK4/6 inhibitor palbociclib. (2018). doi: 10.15252/embj.201798359.

Tedizolid is a member of the oxazolidinone class of antibiotics. These antibiotics are considered drugs of last resort against multiple drug resistant infections such as methicillin-resistant Staphylococcus aureus (MRSA). As part of a program to encourage new antibiotics to combat drug resistance, the FDA fast-tracked the approval of tedizolid for MRSA skin and skin structure infections in 2014.

Tedizolid works by binding to the 50S ribosomal subunit in bacteria, which inhibits protein synthesis.

The medical community often repurposes FDA-approved drugs to treat new diseases. Recently, Tang et al. investigated tedizolid’s potential to treat M. abscessus complex, a mixture of M. abscessus, M. massiliense, and M. bolletii bacteria. M. abscessus complex is notoriously difficult to treat when it infects the lungs. The standard therapy of clarithromycin and amikacin has only a 30-50% cure rate.

Tang et al. compared tedizolid’s effectiveness to clarithromycin and linezolid, another oxazolindone antibiotic. They applied a series of concentrations of antibiotic to M. abscessus cultures to determine the minimum inhibitory concentration (MIC). Tedizolid has a comparable MIC to linezolid and a lower MIC than clarithromycin.

A time-kill assay determined that tedizolid is bacteriostatic, not bactericidal against M. abscessus complex. Pre-exposure to low concentrations of tedizolid did not induce resistance. Tedizolid does not have antagonistic interactions with other antibiotics. Together, these experiments suggest tedizolid could be used in combination therapy to treat M. abscessus complex.

LKT Labs carries a number of antiobiotic compounds for research use, including:

A5132 Amikacin Disulfate

C4502 Clarithromycin

L3453 Linezolid

T165131 Tedizolid

Tang YW, Cheng B, Yeoh SF, Lin RTP, Teo JWP. Tedizolid Activity Against Clinical Mycobacterium abscessus Complex Isolates-An in vitro Characterization Study. Front Microbiol. 2018 Sep 7;9:2095. doi: 10.3389/fmicb.2018.02095.

A 83-01 (LKT Product: A001001)

A 83-01 is an inhibitor of ALK-5 (activin receptor-like kinase), a member of the TGF-β (transforming growth factor-β) superfamily. Recent work shows importance of this small molecule in the morphogenesis of stem cells. In one study, A-83-01 in conjunction with other small molecules resulted in the development of induced pluripotent stem cells from human urine-derived cells. An additional study used A-83-01 in conjunction with 2 other small molecules to convert mature hepatocytes to chemically induced liver progenitor cells. These novel cells were sustainable and able to be serially passaged.

BAY 80-6946 Hydrochloride (LKT Product: B0397)

BAY 80-6946 (copanlisib) is a PI3Kα (phosphatidylinosital-3-kinase) and PI3Kδ selective inhibitor. In studies looking at the utility of BAY 80-6946 in diffuse large B Cell lymphoma (DLBCL), the compound showed IC50 values for cytotoxicity due to high expression of PI3Kα in this carcinoma. This inhibitor also decreased phosphorylation of Akt. In in vivo mouse xenograft studies, treatment with BAY 80-6946 in conjunction with ibrutinib resulted in cancer remission as a complete response to both kinase inhibitors.

SB 202190 (LKT Product: S041001)

SB 202190 is pyridinyl imidazole inhibitor of p38 MAP kinase. Due to the ubiquitous nature of p38, SB 202190 shows interesting activity in different biochemical systems. One study shows that treatment of HEK 293T cells with SB 202190 resulted in inhibition of the casein kinase 1 (CK1). This was determined with a lack of phosphorylation of CREB. An additional study showed that inhibition of p38 kinase results in the protection of mice infected with H5N1 avian flu. SB 202190 can be used for investigations of other p38 MAP kinase quandries.

References:

Tojo M, Hamashima Y, Hanyu A, Kajimoto T, et al. (2005) “The ALK-5 inhibitor A-83-01 inhibits Smad signaling and epithelial-to-mesenchymal transition by transforming growth factor-β.” Cancer Sci 96(11):791-800. DOI: 10.1111/j.1349-7006.2005.00103.x

Li D, Wang L, Hou J Shen Q et al. (2016) “Optimized Approaches for Generation of Integration-free iPSCs from Human Urine-Derived Cells with Small Molecules and Autologous Feeder.” Stem Cell Reports 6:717-728. DOI: 10.1016/j.stemcr.2016.04.001

Katsuda T, Kawamata M, Hagiwara K, Takahashi R, et al. “Conversion of Terminally Committed Hepatocytes to Culturable Bipotent Progenitor Cells with Regenerative Capacity” Cell Stem Cell. 20:41-55. DOI: 10.1016/j.stem.2016.10.007

Scott WJ, Hentemann MF, Rowley RB, Bull CO et al. (2016) “Discovery and SAR of Novel 2,3-Dihydroimidazo[1,2-c]-quinazoline PI3K Inhibitors:Identification of Copanlisib (BAY 80-6946).” ChemMedChem 11:1517-1530. DOI:10.1002/cmdc.201600148

Paul J, Soujon M, Wengner AM, Zitzmann-Kolbe S, et al. (2017) “Simultaneous Inhibition of PI3Kδ and PI3Kα Induces ABC-DLBCL Regression by Blocking BCR-Dependent and Independent Activation of NF-κB and AKT.” Cancer Cell 31:64-78. DOI: 10.1016/j.ccell.2016.12.003

Shanware NP, Williams LM, Bowler MJ and Tibbetts RS. (2009) “Non-specific in vivo inhibition of CK1 by the pyridinyl imidazole p38 inhibitors SB 203580 and SB 202190.” BMB Reports 42(3):142-147.

Borgeling Y, Schmolke M, Viemann D, Nordhoff C, Roth J and Ludwig S. (2014). “Inhibition of p38 Mitogen-activated Protein Kinase Impairs Influenza Virus-induced Primary and Secondary Host Gene Responses and Protects Mice from Lethal H5NI Infection.” J Biol Chem 289(1): 13-27. DOI: 10.1074/jbc.M113.469239.

Resistance to chemotherapeutics is a common adverse event in the treatment of breast cancer. The chemotherapeutic agent docetaxel is in common use as a chemotherapeutic, but resistance to treatment after long exposure is a common downfall of docetaxel. Overcoming resistance to well used chemotherapeutic agents would be a boon to the fight against cancer.

A recent article found in PLoS ONE investigates the effect of treatment of docetaxel-resistant MCF-7 breast cancer cells with microtubule destabilizing agents, in the hope of overcoming taxane-resistance. The work reported that taxane-resistant MCF-7 cells were still resistant to treatment with vinca alkaloids, but colchicine binding site agents were more potent in the docetaxel-resistant MCF-7 cells than in wild-type MCF-7 cells.

In addition to colchicine, other colchicine binding site agents also showed the same pattern against wild-type and docetaxel resistant MCF-7 cells. One such colchicine binding site agent exhibiting this property was 2-methoxyestradiol.

However, the vinka alkaloids vinorelbine and vinblastine lost potency against the docetaxel-resistant MCF-7 cells. Both of these vinka alkaloids showed about a 3-6 times decrease in potency between wild-type and taxane-resistant cells. The overall potency is still sub-micromolar in the cytotoxicity assay.

In all, colchicine binding site agents may be suitable for co-administration with docetaxel to overcome drug-resistance mechanisms.

These microtubule interacting compounds are available from LKT Laboratories, Inc. for your research needs.

V3253 Vinblastine Sulfate

V3251 Vinorelbine Base

D5709 Docetaxel

C5645 Colchicine

M1678 2-Methoxyestradiol

Wang RC, Chen X Parissenti AM, Joy AA, Tuszynski J, Brindley DN, et al. (2017) “Sensitivity of docetaxel-resistant MCF-7 breast cancer cells to microtubule-destabilizing agents including vinca alkaloids and colchicine-site binding agents.” PLoS ONE 12(8): e0182400. https://doi.org/10.1371/journal.pone.0182400

Curcumin is the active ingredient found in turmeric, a common spice used all over the world. The beneficial effects of curcumin intake have been investigated extensively, but a new paper published in Proceedings from the National Academy of Sciences reports a new target for curcumin.

Researchers report evidence of the protein kinase dual-specificity tyrosine regulated kinase 2 (DYRK2) as a receptor for curcumin. In vitro biochemical assays show that curcumin had an IC50 value of 5 nM against DYRK2. Additionally in an assay against 144 different protein kinases, curcumin is a selective ligand for DYRK2, with an IC50 10 fold greater than the next nearest kinase. The authors further confirm DYRK2 as the target of curcumin by overexpressing DYRK2 in HEK293T cells, and noting a decrease in phosphorylation of tyrosine 25 in the RPT3 subunit of the 26S proteasome, the major target of DYRK2. Additionally, the researchers publish a crystal structure of DYRK2 with curcumin bound in the active site, noting the important amino acid residues for binding.

In cell-based experiments, curcumin shows anti-cancer capabilities. Curcumin shows anti-proliferative, anti-invasive and apoptotic tendencies in MDA-MB-231 triple negative breast cancer cells and HaCaT cells. The researchers also found a synergistic relationship between curcumin and carfilzomib, a proteasome inhibitor marketed for the treatment of triple negative breast cancer patients and multiple myeloma. Curcumin in conjunction with other proteasome inhibitors could make an interesting combination for the treatment of disease.

LKT Laboratories, Inc. offers curcumin for research at two different specifications, to meet all your research needs.

C8069 Curcumin, research grade
C8070 Curcumin, high purity
C0271 Carfilzomib

Banerjee S, Chenggong J, Mayefield JE, Goel A et al. “Ancient drug curcumin impedes 26S proteasome activity by direct inhibition of dual-specificity tyrosine-regulated kinase 2.” Proc. Nat. Acad. Sci. 2018, 115(32): 8155-8160. doi: 10.1073/pnas.1806797115.

A recent study published in Frontiers in Neuroscience reports beneficial effects of the tobacco cembranoid, β-cembrenediol for Parkinson’s Diesease (PD). Researchers report encouraging results in both in vitro and in vivo 6-hydroxydopamine PD model, a model that mimics the long-term neurodegeneration found in PD-affected brain tissue.

The researchers found that when co-administered with 6-hydroxydopamine, β-cembrenediol increased cell viability of neuro-2a cells to 80% of control levels, compared to only 55% viability in cells treated only with 6-hydroxydopamine. β-cembrenediol also returned phosphorylated Akt and HAX-1 protein to levels near untreated cells. It also decreased the amount of cleaved caspase-3 found in 6-hydroxydopamine treated cells.

Additionally, the researchers performed two motor tests of rat models with 6-hydroxydopamine. Sprague-Dawley rats treated with 6-hydroxydopamine show limb asymmetry and motor dysfunction in a cylinder test and corner test experiment. The researcher found that when β-cembrenediol was co-administered with 6-hydroxydopamine, the rates returned to normal motor function after 4 weeks post- injection. Immunohistochemical staining of brain tissue from these rats also demonstrated a return to normal looking tissue compared to untreated animals.

This study demonstrates the potential of tobacco cembranoids for the treatment of neurological disorders.

Tobacco cembranoids available from LKT Laboratories, Inc. include:

C1649 β-cembrenediol
C1648 α-cembrenediol 
C1650 β-cembrenediol methyl ether

Hu J, Ferchmin PA, Hemmerle AM et al. (2017) 4R-Cembranoid Improves Outcomes after 6-Hydroxydopamin Challenge in Both In Vitro and In vivo Models of Parkinson’s Diesease. Front. Neurosci. 11:272. doi: 10.3389/fnins.2017.00272.

Rho-associated protein kinase (ROCK) belongs to the family of serine/threonine kinases. Research shows that ROCK signaling plays a role in several diseases, including diabetes, Parkinson’s, amyotrophic lateral sclerosis, pulmonary hypertension, and cancer.

A new study published in January 2017 demonstrates that ROCK2 has a larger impact on the regulation of Ewing sarcoma (EWS) malignancy than ROCK1. In patient-derived cell lines, ROCK2 expression was higher in the metastasis derived cell line compared to the primary tumor derived cell line. Gaining a better understanding of ROCK inhibition may provide new insights on treatment of sarcomas¹.

Another study found that inhibition of the RhoA/ROCK pathway has a protective effect on glomerular inflammation found in diabetic nephropathy. Treatment with the inhibitor Y27632 decreased the release of adhesion molecules in rat glomerular endothelial cells incubated with advanced glycation end products. Blocking this pathway protects the kidneys and improves kidney function without causing inflammation².

LKT Labs offers several high purity ROCK inhibitors for research use.

F0275 Fasudil Hydrochloride

G7443 GSK-429286A  

H0003 H89

P0255 Pantoprazole

P0256 Pantoprazole Sodium Sesquihydrate

R4132 RKI-1447 

T3132 Thiazovivin

V9201 VX-11e

Y1000 Y27632 Dihydrochloride

1. Oncol Rep. 2017 Jan 20. doi: 10.3892/or.2017.5397. Targeting ROCK2 rather than Rock1 inhibits Ewing sarcoma malignancy. [Epub ahead of print]

2. Sci Rep. 2017 Jan 5;7:39727. doi: 10.1038/srep39727. Inhibition of the RhoA/ROCK pathway can benefit the kidneys in diabetics.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are protein channels found in the plasma membranes of heart and brain cells that regulate neuronal excitability. HCN is well-known and used for the contribution of its pacemaker function to cardiac rhythm. In addition, several studies have linked the activities of HCN channels to both epilepsy and pain.

A recent study at the Icahn School of Medicine contends HCN channels to have substantial potential as a target for major depressive disorder therapeutics. Several animal models of depression have been able to demonstrate that ionic mechanisms play a key role in neuronal homeostasis and dysregulation. Because HCN channels are confirmed to regulate neuronal excitability, they may also have a role in mediating depression-related excitability.

A recent study by Tae, et al using transgenic mice showed that gabapentin impacted several HCN4 channels and had only a slight effect on HCN1 channels. Currently, there are very few drugs known to effect individual HCN channels. Therefore, gabapentin may be useful in studying the function of HCN4 specifically.

G0106 Gabapentin

Related Product Categories:

Analgesics and Antinociceptives

Antidepressants

Antiepileptics and Anticonvulsants

Sedatives and Hypnotics

References:

Ku SM, Han MH. HCN channel targets for novel antidepressant treatment. Neurotherapeutics. 2017 Jul;14(3):698-715. doi: 10.1007/s13311-017-0538-7.

Tae HS, Smith KM, Phillips AM, et al. Gabapentin modulates HCN4 channel voltage-dependence. Front Pharmacol. 2017 Aug 21;8:554. doi: 10.3389/fphar.2017.00554.

The endocannabinoid system is a set of proteins and endogenous ligands that regulates a variety of biological processes. It consists of cannabinoid receptors 1 (CB1) and 2 (CB2), the natural ligands 2-arachidonyl glycerol (2-AG) and N-arachidonylethanolamide (AEA or Anandamide), as well as proteins responsible for the hydrolysis of these ligands, such as monoacyl glycerol lipase (MAGL), fatty acid amide hydrolase (FAAH) and alpha/beta hydrolase domain 6 (ABHD6). CB1 is located mainly in brain tissues, while CB2 is found in the periphery. Endocannabinoid modulation is a research topic in neuroscience, immunology, cancer and obesity research.

Cannabinoid receptors 1 and 2 are G-protein coupled receptors (GPCRs). The results of activation/inhibition of CB1 and CB2 are still being explored.

CB Mixed Agonists

Besides endogenous ligands 2-AG and AEA, many synthetic endocannabinoids have been discovered. Mixed agonists (which interact with both CB1 and CB2) include WIN 55,212-2 and CP 55,940. Both of these agonist are able stimulate cannabinoid signaling, with no preference between the two receptors. Stimulation of CB1 and CB2 has been tied to analgesia, anti-diabetic, anti-obesity and anti-inflammation.

W317520 WIN 55212-2

C600000 CP 55,940

Selective CB antagonists

Antagonism of the cannabinoid receptors is under study for decreasing CB signaling. CB antagonists have been used in neuroscience, cancer and immunology research. AM251, a selective CB1 inverse agonist demonstrated benefits in an anti-obesity system. AM630, a selective CB2 inverse agonist, activates TRPA1 in sensory neurons.

CB1 Antagonists/Inverse Agonists

A480000 AM251

R3449 Rimonabant

CB2 Antagonists/Inverse Agonists

A480010 AM630

S680000 SR144528

J766160 JTE907

CB2 Agonists

CB2 selective agonists are ubiquitous throughout current academic literature. Synthetic CB2 agonists have been used to study the role of endocannabinoids in neurodegenerative disorders, diabetes, obesity and cancer. Agonists of the CB2 receptor have especially shown benefits as analgesic and anti-allodynic compounds.

L000033 L-759,633

H800010 HU308

J889290 JWH 133

J889280 JWH 015

G880000 GW 405833

A480020 AM1241

S182680 SER601

M184770 4-O-methylhonokiol

FAAH Inhibitors

Fatty acid amide hydrolase (FAAH) is responsible for the hydrolysis of AEA to arachidonic acid. Inhibition of FAAH results in an increase in AEA, which can stimulate CB1 and CB2 and activate down stream signaling pathways. FAAH inhibition is under investigation for pain attenuation and the reduction of neuro-inflammation. FAAH inhibitor URB597 demonstrates analgesic effects in mice. Inhibitor PF-3845 also reduces pain in mice stimulated with LPS, and reduces inflammation in mice models for traumatic brain injury.

U682040 URB597

P200000 PF-3845

MAGL Inhibitors

Monoacylglycerol lipase (MAGL) is responsible for the hydrolysis of 2-AG to arachidonic acid. Increasing the amount of 2-AG stimulates cannabinoid signaling. Inhibition of MAGL increases 2-AG, showing the benefits of increased 2-AG. JZL 184, an inhibitor of MAGL decreases pain in multiple mouse models, showing anti-nociceptive and reducing pain-related to cancer drugs in mice. URB602, another inhibitor of MAGL, also demonstrates anti-nociceptive properties.

J974440 JZL 184

U682042 URB602

ABHD6 Inhibitors

Alpha/Beta hydrolase domain 6 (ABHD6) also hydrolyzes 2-AG to arachidonic acid. The ABHD inhibitor WWL70 reduces weight gain in diet-induced obese mice. It also has anti-inflammatory properties by reducing the amount of pro-inflammatory prostaglandin expression.

W894440 WWL70

References:

Aquirre-Rueda D, Guerra-Ojeda S, Aldasoro M et al. WIN 55,212-2, agonist of cannabinoid receptors, prevents amyloid beta1-42 effects on astrocytes in primary culture. PLoS One. 2015 Apr 13;10(4):e0122843. PMID: 25874692

Hamamoto DT, Giridharagopalan S, and Simone DA. Acute and chronic administration of the cannabinoid receptor agonist CP 55,940 attenuates tumor-evoked hyperalgesia. Eur J Pharamacol. 2007 Mar 8;558(1-3): 73-87. PMID: 17250825.

Patil M, Patwardhan A, Salas MM, et al. Cannabinoid receptor antagonists AM251 and AM630 activate TRPA1 in sensory neurons. Neuropharmacology, 2011. Sep;61(4):778-88. PMID: 21645531.

Jenkin KA, O’Keefe L, Simcocks AC, et al. Chronic administration of AM251 improves albuminuria and renal tubular structure in obese rats. J Endocrin. 2015 May;225(2)113-24. PMID: 25804605.

Negrete R, Hervera A, Leazez S et al. The antinociceptive effects of JWH-015 in chronic inflammatory pain are produced by nitric oxide-cGMP-PKG-KATP pathway activation mediated by opioids. PLoS One. 2011;6(10):e26688. PMID: 22031841.

Ibrahim MM, Deng H, Zvonok A et al. Activation of CB2 cannabinoid receptors by AM1241 inhibits experimental neuropathic pain: pain inhibition by receptors not present in the CNS. Proc Natl Acad Sci USA. 2003 Sep 2;100(18):10529-33. PMID: 12917492.

Kwilasz AJ, Abdullah RA, Poklis JL et al. Effects of the fatty acid amide hydrolase inhibitor URB597 on pain-stimulated and pain-depressed behavior in rats. Behav Pharmacol. 2014 Apr;25(2):119-29. PMID: 24583930

Booker L, Kinsey SG, Abdullah RA et al. The fatty acid hydrolase (FAAH) inhibitor PF-3845 acts in the nervous system to reverse LPS-induced tactile allodynia in mice. Br J Pharmacol. 2012 Apr;165(8):2485-96. PMID: 21506952.

Comelli F, Giagnoni G, Bettoni I et al. The inhibition of monoacylglycerol lipase by URB602 showed an anti-inflammatory and anti-nociceptive effect in a murine model of acute inflammation. Br J Pharmacol. 2007 Nov;152(5):787-94. PMID:17700715.

Woodhams SG, Wong A, Barrett DA et al. Spinal administration of the monoacylglycerol lipase inhibitor JZL 184 produces robust inhibitory effects on nociceptive processing and the development of central sensitization in the rat. Br J Pharmacol. 2012 Dec;167(8):1609-19. PMID: 22924700.

Tanaka M, Moran S, Wen J et al. WWL70 attenuates PGE₂ production derived from 2-arachidonoylglycerol in microglia by ABHD6-independent mechanism. J Neuroinflammation. 2017 Jan 10;14(1):7. PMID: 28086912.

Cyclin-dependent kinases (CDKs) are an enzyme family that control cellular proliferation and growth. The interaction of CDKs with D-type cyclins results in the inactivation of retinoblastoma (Rb) tumor suppressor protein. Inhibiting the CDKs therefore allows the tumor suppressor to remain active.

Abemaciclib has previously demonstrated antitumor activity in HR+/HER2 metastatic breast cancer, renal cell carcinoma and several other solid tumor types. It’s been found to selectively inhibit CDK4 and CDK6. A recent study by Kosovec et al, further tests the potential of abemaciclib, this time for the treatment of esophageal adenocarcinoma (EAC).

The study evaluated several cell lines, monitoring apoptosis, proliferation, and pathway regulation during treatment with abemaciclib. Additionally, animals were induced to develop EAC and then treated with abemaciclib by intraperitoneal injection. The study was quite successful, the treated animals showed decreased tumor volumes and decreased prevalence of the disease altogether, while the treated cell lines showed increased apoptosis and decreased proliferation.

Overactive CDKs or inactive Rb protein are a common thread among several different cancer types, which makes CDK an interesting target of investigation for cancer treatments.

A044176 Abemaciclib

Full List of CDK Inhibitors

Reference:

Kosovec JE, Zaidi AH, Omstead NA, et al. CDK4/6 dual inhibitor abemaciclib demonstrates compelling preclinical activity against esophageal adenocarcinoma: a novel therapeutic option for a deadly disease. Oncotarget. 2017 Nov 1;8(59):100421-100432. doi: 10.18632/oncotarget.22244.

The Karyopherin superfamily consists of seven known proteins that mediate the majority of transport of molecules through the nuclear pores in a cell nucleus.

One of these proteins: chromosome region maintenance1 (CRM1, aka XPO1 or exportin1) is a key transporter protein that exports cargo from within the cell nucleus out to the cytoplasm. The role of CRM1 is to export tumor suppressor proteins and growth regulatory proteins.

Over-expression of CRM1 has been found in various malignancies and leads to mislocalization of several growth and survival factors. Inhibiting CRM1 leads to an accumulation of tumor suppressor proteins, which eventually triggers apoptosis, killing off the problem causing cell. CRM1 also plays an important role in viral replication. Preventing this protein, which the virus is dependent on for survival, to function should then prevent the virus from replicating, effectively shutting it down.

Lab studies have found that the CRM1 inhibitor KPT-276 shows activity against several types of cancer, including glioblastoma, lung cancer, and breast cancer, among others.

Studies on the CRM1 inhibitor verdinexor have shown that these inhibitors also act as antiviral agents. Both in vitro and in vivo studies have demonstrated the antiviral benefit of a treatment based on CRM1 inhibition, particularly in the face of the drug resistance that has developed against common antiviral drugs.

The CRM1 inhibitors KPT-276 and Verdinexor are now available from LKT Laboratories for further research use.

References

Mathew C, Ghildyal R. CRM1 inhibitors for antiviral therapy. Front Microbiol. 2017;8:1171. doi: 10.3389/fmicb.2017.01171.

Cheng Y, Holloway MP, Nguyen K, et al. XPO1 (CRM1) inhibition represses STAT3 activation to drive a survivin-dependent oncogenic switch in triple-negative breast cancer. Mol Cancer Ther. 2014 Mar; 13(3):675-686. doi: 10.1158/1535-7163.MCT-13-0416.

Wang S, Han X, Wang J, et al. Antitumor effects of a novel chromosome region maintenance 1 (CRM1) inhibitor on non-small cell lung cancer cells in vitro and in mouse tumor xenografts. PLoS One. 2014 Mar 4;9(3):e89848. doi: 10.1371/journal.pone.0089848

Green Al, Ramkissoon SH, McCauley D, et al. Preclinical antitumor efficacy of selective exportin 1 inhibitors in glioblastoma. Neuro Oncol. 2015 May;17(5):697-707. doi: 10.1093/neuonc/nou303.

Lundberg L, Pinkham C, de la Fuente C, et al. Selective inhibitor of nuclear export (SINE) compounds alter new world alphavirus capsid localization and reduce viral replication in mammalian cells. PLoS Negl Trop Dis. 2016 Nov 30;10(11):e0005122. doi: 10.1371/journal.pntd.0005122.

Perwitasari O, Johnson S, Yan X, et al. Antiviral efficacy of verdinexor in vivo in two animal models of influenza A virus infection. PLoS One. 2016 Nov 28;11(11):e0167221. doi: 10.1371/journal.pone.0167221.