αCT1 Peptide Weakens Cancerous Glioma Cells

Glioblastoma (GBM) is the most commonly occurring terminal brain cancer. Due to complications in the brain like the blood brain barrier, methods of treating GBM are few and far between. Therefore, treatment in the region is generally left to specific chemotherapeutics like temozolomide (TMZ), which has the unique capability to bypass the brain blood barrier. However, matters become more complicated as many subpopulations of GBM, namely the glioma stem cell populations, are resistant to TMZ. Researchers are looking into ways to bypass this resilience, namely connexin 43 (Cx43) hemichannels that when inhibited by mimetic peptides allow the glioma stem cell populations to be treated significantly more effectively by TMZ

Cx43 mimetic peptides weaken cancer’s resistance to TMZ

Researchers used LifeTein’s peptide synthesis service to create two mimetic peptides of Cx43, αCT11 and αCT1, to inhibit Cx43 hemichannels and then sensitize the glioma cells and other GBM cell populations to TMZ in a 3D hyaluronic acid and collagen hydrogel-based tumor organoid system. After testing this model extensively, the group found that only the αCT1 peptide in combination with TMZ proved effective in treating the cell lines. It is believed that the αCT1 is more successful due to its cell penetrating sequence when compared to αCT11.

Overall, the group emphasizes that the model used does not accurately mimic the cellular heterogeneity of GBM, but the results are a fantastic start and can be used as a tool to further study treatment of this aggressive brain cancer. Further work can optimize this treatment and can hopefully provide a chance for those who have to go against this fatal ailment.

Jingru Che, Thomas J. DePalma, Hemamylammal Sivakumar, et al. αCT1 Peptide Sensitizes Glioma Cells to Temozolomide in a Glioblastoma Organoid Platform. Authorea. April 29, 2022.

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A six-mer synthetic peptide (AT1002) showed enhanced nasal drug delivery

Zonula occludens toxin (Zot) and its biologically active fragment, delta G, have been shown to reversibly open tight junctions (TJ) in endothelial and epithelial cells. AT1002, a six-mer synthetic peptide H-FCIGRL-OH of ZO toxin was identified and synthesized that retains the Zot permeating effect on intercellular TJ. It was found that AT1002 disrupts the epithelial barrier while larazotide acetate restores barrier function by rearrangement of actin. In addition, AT1002 enhances the transport of molecular weight markers or agents with low bioavailability with no cytotoxicity. So this synthetic peptide AT1002 is a tight junction modulator with promising permeation-enhancing activity.

A Synthetic Peptide Showed Enhanced Nasal Drug Delivery

The C-terminal amidated AT1002 FCIGRL-NH2 showed enhanced nasal drug delivery and may lead to the development of a practical drug delivery technology for drugs with low bioavailability. The synthetic peptide AT1002 was synthesized by LifeTein.
Peptide amidation

Peptide amidation

https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-018-0481-z https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4383222/

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Monitoring T cell–dendritic cell interactions in vivo using labeled peptides

The SrtA substrates Biotin–aminohexanoic acid–LPETGS and SELPETGG were used for the interactions between immune cells ‘Labelling Immune Partnerships by SorTagging Intercellular Contacts’ (LIPSTIC). The peptide-receptor interactions enable the direct measurement of dynamic cell–cell interactions. The peptides are flexible tools for use with different receptor–ligand pairs and a range of detectable labels.

peptide-receptor interaction

Schematic representation of the LIPSTIC approach

 

Nature, Monitoring T cell–dendritic cell interactions in vivo by intercellular enzymatic labelling

Peptide Biotin–aminohexanoic acid–LPETGS, SELPETGG was purchased from LifeTein.

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How do peptides fold?

How HIV-1 integrase contributes to virion morphogenesis?

LifeTein Launches Rush Custom Peptide Synthesis Service: Peptide Delivered in 3-5 Days

LifeTein is unveiling an expedited peptide synthesis program, promising to place peptides in its customers’ hands within 3-5 business days. The RushPep™ peptide synthesis service was designed to circumvent the existing limitations of conventional solid-phase peptide synthesis (SPPS), which involves a long coupling time and low yield. RushPep™ shortens the time needed for individual coupling, deprotection and washing steps. The proprietary methodology renders processing ten times faster than in classical synthesis while simultaneously circumventing the limitations caused by the formation of by-products or intermediates to which traditional SPPS approaches are subject.

LifeTein’s Rush Custom Peptide Synthesis Service

“When designing the RushPep™ methodology, our focus was to not only to produce peptides of high quality and purity but also to offer a streamlined solution that would increase the efficiency of researchers’ protein discovery workflows,” stated Dr. Ya Chen, Head of LifeTein’s Rush Peptide Synthesis Group. “RushPep™ achieves these goals by synthesizing the peptides in 3–5 business days to accelerate research and discovery.”

Chen continued, “The reliability of RushPep™ rush peptide synthesis ensures that the peptides are finished in 3–5 business days with high-batch-to-batch reproducibility. ” Most of the crude peptides have a purity of over 80%. RushPep™ peptide service is valuable for the scientists and researchers because it allows them to finish their proteomics projects in a fast and cost-efficient manner.

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Peptides for Parkinson’s disease (PD)

ID2 peptide for inhibition of tumour growth

How does BIRD-2 peptide kill B-cell lymphoma?

Look Who’s Talking

How does BIRD-2 peptide kill B-cell lymphoma?

The anti-apoptotic factor Bcl-2 is over-expressed in B-cell lymphoma cells as their main survival mechanism by binding to IP3R2 on endoplasmic reticulum (ER).  In this study, a cell-penetrating version of BIRD-2 peptide (Bcl-2/IP3R Disrupter-2 peptide with a TAT sequence) made by LifeTein was used to break up the complex formed by Bcl-2 and IP3R2 in human diffuse large B-cell lymphoma (DLBCL) cells. Ca2+ signaling-related events are suggested to be the killing mechanism of BIRD-2 peptide on DLBCL cells.

Bird-2 Peptides & B-Cell Lymphoma

[PDF] Inhibiting Bcl-2 via its BH4 domain in DLBCL cancers to provoke pro-apoptotic Ca2+ signaling

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Peptides for Parkinson’s disease (PD)

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LifeTein Launches Rush Custom Peptide Synthesis Service: Peptide Delivered in 3-5 Days

Nanoparticles Get Help from Cell-Permeable Peptides

Some cell-permeable peptides are able to carry cargos across cell membrane even without any covalent links.  Biotinylated peptides, including L- and D-TAT peptides made by LifeTein were used in this study to show that two types of cell surface receptors, heparan sulfate proteoglycans and Neuropilin-1, play critical roles in the delivery of silver-based nanoparticles into cells by cell-permeable peptides.

Nano Particles & Cell-Permeable Peptides

Science Advances 06 Nov 2015: Vol. 1, no. 10, e1500821 DOI: 10.1126/sciadv.1500821.  Neuropilin-1 and heparan sulfate proteoglycans cooperate in cellular uptake of nanoparticles functionalized by cationic CPP peptides.

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Predicting type 1 diabetes in children

Improving Antibody Therapy For Colorectal Cancer

A tumor-permeable peptide iRGD by LifeTein targets peritoneal carinomatosis

To Make Simpler and Better Biosensors

A New Patent Using Peptides

A tumor-permeable peptide iRGD by LifeTein targets peritoneal carinomatosis

A tumor-penetrating peptide, iRGD, was synthesized by LifeTein. It was found that iRGD improves tumor-specific penetration of intraperitoneal compounds and enhances intraperitoneal chemotherapy (IPC) in mice. This penetration was tumor-specific. When the fluorescein was attached to iRGD and mixed with nanoparticles, the mixture could penetrate into fresh human peritoneal metastasis explants. The evidence proved that the LifeTein iRGD enhanced intratumoral entry. The intraperitoneal iRGD co-administration is a simple and effective strategy to facilitate tumor detection and potential application for the therapeutic improvement.

LifeTein’s Peptide: iRGD

A tumor-penetrating peptide enhances circulation-independent targeting of peritoneal carcinomatosis, Journal of Controlled Release, Volume 212, 28 August 2015, Pages 59–69

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Nanoparticles Get Help from Cell-Permeable Peptides

Predicting type 1 diabetes in children

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To Make Simpler and Better Biosensors

A New Patent Using Peptides

Peptide Applications

Peptides can be used in a wide variety of research applications:

Anti-microbial Peptides

81 oligopeptides were synthesized by LifeTein and tested for inhibition of Enterococcus faecalis V583. Three peptides were found to inhibit V583. The peptide (NH2-VAVLVLGA-COOH) possessed activity in picomolar concentrations, being >10^6 -fold more active than the only other two and showing inhibitory activity. Pheromone killing of multidrug-resistant Enterococcus faecalis V583 by native commensal strains, PNAS, 2015 The fungal pathogen causes the skin disease for amphibians. Use of a potent antibiotic cocktail dramatically reduced culturable skin bacteria within 48 h. The synthetic peptides by LifeTein were used to reduce the skin bacteria. SSkin bacteria provide early protection for newly metamorphosed southern leopard frogs (Rana sphenocephala) against the frog-killing fungus, Batrachochytrium dendrobatidis, Biological Conservation, 2015

Anti-inflammatory Peptides

Anti-inflammatory peptides were isolated from alcalase hydrolysates out of tuna cooking juice by-product. Synthetic peptides from LifeTein were used to confirm the inhibitory anti-inflammatory activity. The amino acid sequences of the two anti-inflammatory peptides isolated from AH hydrolysates were Pro-Arg-Arg-Thr-Arg-Met-Met-Asn-Gly-Gly-Arg (1543.8 Da) and Met-Gly-Pro-Ala-Met-Met-Arg-Thr-Met-Pro-Gly (1211.5 Da).

Epitope Mapping

Peptide scanning involves the chemical synthesis of overlapping peptides covering the antigen sequence targeted by the investigated antibodies. Peptide truncations are used to further narrow down the epitope sequence and mutagenesis of each amino acid such as alanine substitution can also indicate the binding affinity. Cross-reactive epitopes were found in Borrelia burgdorferi p66. Cross-reactive epitopes in Borrelia burgdorferi p66, Clinical and Vaccine Immunology, 2015

Cell Penetrating Peptides and Scrambled Peptides

The CD81 peptides tagged with cell penetrating peptide RRRRRRR were used for the binding assay. The synthetic peptides from LifeTein were used to investigate the role of CD81 in the regulation of defense mechanisms against microbial infections. The scrambled peptides, RRRRRRR- CCGIRNSSVY, were used as the negative control for the study. CD81 Controls Immunity to Listeria Infection through Rac-Dependent Inhibition of Proinflammatory Mediator Release and Activation of Cytotoxic T Cells, The Journal of Immunology, 2015

Receptor Binding Study

His-tagged GLP-1 (7-36), glucagon, and gastric inhibitory polypeptides (GIP) by LifeTein were used to study GLP-1 receptor signaling regulation. The GLP-1 peptides bind specifically with lipids but not that of exendin 4.The His-Tagged GLP-1 were used for the binding reaction. The free peptide was captured by Cu++-NTA resin. The results indicated that His-tagged GLP-1 peptide binds to OEA in a dose-dependent and saturable way. Modulation of Glucagon-like Peptide (GLP)-1 Potency by Endocannabinoid-like Lipids Represents A Novel Mode of Regulating GLP-1 Receptor Signaling. Journal of Biological Chemistry, 2015

Antibody Blocking Peptides

Peptides can be used as blocking peptides for the competition assay. The excess of blocking peptides (20:1 peptide: antibody ratio) from LifeTein were mixed with antibodies. The antibody was neutralized in this way by incubating with an excess of peptide that corresponds to the epitope recognized by the antibody. The neutralized antibody is then used side-by-side with the antibody alone, and the results are compared. Whole Exome Sequencing Reveals ZNF408 as a New Gene Associated With Autosomal Recessive Retinitis Pigmentosa with Vitreal Alterations, Human Molecular Genetics, 2015

Protein-Protein Interactions

The B-cell lymphoma 2 (Bcl-2) peptides were biotinylated at N terminus for the protein-protein interactions. The biotin-BH4-Bcl-XL peptide and the scrambled peptide were immobilized on different channels of a streptavidin-coated sensor chip. Studies showed that Bcl-XL bound to the central domain of RyR3 via its BH4 domain. Further analysis of a mutated peptide at a specific site Lys87 showed a reduced binding affinity. These data suggest that BH4 domain and its specific site of Lys87 contributes to the interaction. Ryanodine receptors are targeted by anti-apoptotic Bcl-XL involving its BH4 domain and Lys87 from its BH3 domain, Nature Scientific Reports, 2015

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Phospho-specific antibodies by LifeTein published in Nature

Jia Shen. et al. EGFR modulates microRNA maturation in response to hypoxia through phosphorylation of AGO2. Nature 497, 383–387 (16 May 2013), doi:10.1038/nature12080 LifeTein helped designed and synthesized a series of phosphorylated s. Then the peptides were used for phospho-specific productions. The phospo-specific antibodies by LifeTein were confirmed to react with the epidermal growth factor receptor (EGFR). The Hung’s lab showed that AGO2-Y393 phosphorylation mediates EGFR-enhanced cell survival and invasiveness under hypoxia. These findings suggest that modulation of miRNA biogenesis is important for stress response in tumour cells. … The following peptides were chemically synthesized for in mice (Lifetein Conc.), Elisa verification (LifeteinConc.) and peptide competition assay in immunohistochemistry (IHC)… Supplementary information

Phospho-Specific Antibodies by LifeTein

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LifeTein Peptide Cited in Cell

Synthesis of multiple antigenic peptides: strategies and limitations

The Structural Basis of Peptide-Protein Binding Strategies

Synthetic Peptides Used for indirect ELISA

 

Peptide Synthesis for Cell-penetration Studies

Cell-penetrating peptides (CPPs) have the ability to enter a cell’s plasma membrane independent of a membrane receptor. Attached to a CPP, therapeutic cargo could be delivered to an intracellular target, thus overcoming the entry restrictions set by the plasma membrane.

Peptide Synthesis & Cell Penetration

The cationic CPPs interact with negatively charged head groups of lipids directly in the plasma membrane through electrostatic interactions. The increased local peptide concentration at the membrane surface will cause a transient destabilization of the lipid bilayer and lead to cell entry. The hydrophobic interactions, especially facilitated by the presence of tryptophan residues, may be important for the CPP-membrane interaction and cellular internalization.

Please click here for more details for cell penetrating peptide synthesis services: http://lifetein.com/Cell_Penetrating_Peptides.html

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Amino acid composition of cell-penetrating peptides (CPPs)

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D-amino acid peptides to resist common proteases

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