Platinum based anticancer drugs generally go hand-in-hand with DNA, however their interactions with proteins are important to understand as well. A group focused their work on discovering and further exploring binding sites of cisplatin onto both an oligonucleotide and two peptides corresponding to segments of H2A and H2B histone proteins via mass spectrometry. The study revealed key interactions and the mechanism of cisplatin binding with oligonucleotides and peptides, and eventually DNA as well.
Peptide and oligonucleotide competitive binding with platinum
LifeTein supplied the group with two peptides for the project; P1, from the acidic region of H2a, and P2, from the α2-helix of H2B human histone protein. These peptides and an oligonucleotide model of DNA were analyzed using electrospray ionization high-resolution mass spectrometry and tested with substantial theoretical figures to match the fragments. Here the group found the preferred binding sites on both of the peptides and the oligonucleotide, of relevance are the multiple histidine and methionine residues on P2 that saw the most binding to cisplatin over P1.
The adducts formed on platinated P2 were tested and incubated solely with the oligonucleotide, where after two days the group found that a portion of the platinum fragments had migrated from the peptide to the oligonucleotide. This observation not only showed that the oligonucleotide was perhaps the more thermodynamically favored product, but also gave insight into how the cisplatin drug takes to DNA during chemotherapy, by binding to the proteins first and then reversing the reaction and migrating. The long-term implications of this mechanism will surely be researched and explored in the future of platinum drug delivery and cancer treatment.
Mansouri, F., Patiny, L., Ortiz, D. et al. Simultaneous mass spectrometry analysis of cisplatin with oligonucleotide-peptide mixtures: implications for the mechanism of action. J Biol Inorg Chem 27, 239–248 (2022). https://doi.org/10.1007/s00775-022-01924-9
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.
After the gut, the mouth is most important microbiome in the human body, with the inhabitants ranging from bacteria and fungi to viruses and protozoa. If this careful balance of microorganisms is thrown off even by a little, certain pathogens could propagate and cause serious periodontal diseases. One such pathogen is Porphyromonas gingivalis (P. gingivalis), that degrades the components of the specialized basal lamina that protects supporting tissues in the teeth. However, one component of this specialized basal lamina, the secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1) protein, had shown to be not only resistant to P. gingivalis, but to also affect the cell membrane of P. gingivalis itself. A group of researchers then decided to explore these antimicrobial properties of the SCPPPQ1 protein and its peptide derivatives.
SCPPPQ1 protein and peptide derivatives as antibacterial agents
Using the SCPPPQ1 protein itself and derived peptides synthesized by LifeTein, the group sought to test how they fared against P. gingivalis in isolated conditions. After incubating the two together, results showed rapid and significant decrease of P. gingivalis population. The means of which were narrowed down to aggregation of bacteria and membrane disruption.
The group went further and tested the antibacterial properties against other pathogens, and though there were results, none were as significant as those against P. gingivalis. The results point towards a more honed treatment against P. gingivalis in the future using this knowledge of the SCPPPQ1 protein and its peptide derivatives. Since the protein itself is native in the human mouth, further application to treat periodontal pathogens with its antibacterial properties is not out of the question.
Mary, C., Fouillen, A., Moffatt, P. et al. Effect of human secretory calcium-binding phosphoprotein proline-glutamine rich 1 protein on Porphyromonas gingivalis and identification of its active portions. Sci Rep 11, 23724 (2021). https://doi.org/10.1038/s41598-021-02661-w
Peptide nucleic acids (PNAs) are synthetic mimics of DNA. The deoxyribose phosphate backbone of PNAs is replaced by a pseudo-peptide polymer. These specific physicochemical properties are exploited to develop a wide range of powerful biomolecular tools, including molecular probes, biosensors, and antigene agents. The PNA molecules can routinely be labeled with biotin, azido, cell penetration peptide fragments, or fluorophores such as FITC, Cy3, Cy5, Cy7, Alexa Dyes, and pyrene.
The uncharged synthetic backbone provides PNA with unique hybridization characteristics. It gives higher stability, or a higher thermal melting temperature (Tm) to the PNA–DNA or PNA–RNA duplexes than the natural homo- or heteroduplexes. In addition, the unnatural backbone of PNAs is not degraded by nucleases or proteases.
It was shown that the binding of PNA to complementary DNA can efficiently block transcriptional elongation and inhibit the binding of transcriptional factors. Thus, the PNAs can be used as antisense or antigene therapeutic agents. PNAs can be used as adapters to link peptides, drugs, or molecular tracers to plasmid vectors. One concept is to form the duplexes of PNAs – cell penetration peptides. The duplexes can penetrate into cells and be used in anticancer applications. The nuclear localization signal (NLS) peptide-PNAs duplexes gave a much higher nuclear localization of a coupled nuclear localization signal than did the free oligonucleotide.
The strategy of PNA-directed PCR clamping is used to inhibit the amplification of a specific target. This PNA–DNA complex formed at one of the primer sites effectively blocks the formation of the PCR product. The procedure can be used to detect single base-pair gene variants for mutation screening and gene isolation. The biotinylated short PNA probes can be used as generic capture probes for the purification of nucleic acids via streptavidin beads. Other applications could be solid-phase hybridization, and fluorescence in situ hybridization (PNA-FISH).
PNA-based applications benefit from the unique Physico-chemical properties of PNA molecules, enabling the development of cell penetration peptide-PNA assays in molecular genetics.
Adult type 2 diabetics are at very high risk of obesity-associated hypertension, where the end result can be as grave as heart failure. The systems involved in the human body regarding these conditions can be complex, but scientists have identified cases of stroke and refractory hypertension that harbored increased plasma IgG, 5-hydroxytryptamine 2A receptor (5-HT2AR)-targeting autoantibodies.
The goal was to test whether a decoy receptor peptide could lower blood pressure in an animal model of obesity-associated hypertension. The team developed the decoy receptor peptide, SCLLADDN (Sertuercept), and LifeTein synthesized it successfully for the project. Using Zucker hypertensive diabetic fatty rats as the model, the team proved their theory.
Results showed after implementing the decoy receptor peptide, acute and long-lasting significant systolic and diastolic blood pressure-lowering occurred within the rat models. This followed through without any long-term side effects after chronic administration. Hopefully, these results are fruitful in later applications and the same peptide can be used to help significantly lower blood pressure in humans afflicted with type 2 diabetes as well.
Alzheimer’s disease as we know it today is a horrible and currently incurable neurodegenerative disorder characterized by neuronal loss, memory impairment, and cognitive decline. Ongoing research is always looking for ways to combat or slow down this disorder, and one such area of interest is the related formation of senile amyloid plaques mainly composed of amyloid β (Aβ) peptides, whose aggregation is thought to be responsible for Alzheimer’s disease pathology. Researchers are implementing gallium nitride nanoparticles as a means to inhibit the formation of the Aβ40 amyloid peptides.
LifeTein supplied the scientists with the Aβ40 peptide necessary for this research, where they would synthesize their nanoparticle with gallium nitrate and observe its inhibition on the peptide in vitro. Gallium nitrate in particular is of interest due to its biocompatibility and aqueous stability, allowing the substance to be useful in numerous biological applications.
After observing their interactions together using the likes of ThT fluorescence, CR absorbance, turbidity, and SEM imaging, the group concluded that the nanoparticle did in fact inhibit the crucial oligomeric nucleus formation of the amyloid β peptide. The group believes a key factor in this is the polarization characteristic of the nanoparticle, where even more polarization could mean more interaction between the nanoparticle and the peptide, and thus less intermolecular interactions among the Aβ40 peptide monomers to form amyloids. Hopefully the future sees more studies on these gallium nitrate nanoparticles, and how further modifications could benefit the fight against Alzheimer’s through these critical Aβ40 peptides.
Torres, K. M., Delgado, A. S., Serrano, E. R., Falcón-Cruz, N. V., Meléndez, A., Ramos, I., Du, D., & Oyola, R. (2021). Gallium nanoparticles as novel inhibitors of Aβ40 aggregation. In Materials Advances (Vol. 2, Issue 16, pp. 5471–5478). Royal Society of Chemistry (RSC). https://doi.org/10.1039/d1ma00461a
A SARS-CoV-2 specific serological assay is necessary as the global pandemic persists. The ability of such an assay to quantify virus antibodies in high and low COVID-19 incidence communities has a multitude of benefits. These include assessment of exposure rates to the virus, the immune responses to vaccination, and the longevity of antibodies from either infection or vaccination.
Spike Protein Peptide Helps Develop Multiplex Assay
Scientists used a multiple of resources to develop their SARS-CoV-2 specific serological assay, including a synthetic peptide of the RBD region of the Spike protein (synthetic RBD) by LifeTein. Overall, the assay proved highly sensitive and specific in monitoring the immune response and antibodies in both individuals and communities.
Some innate limitations to this kind of assay would be cross-reactivity with other human-coronaviruses, though this was not an issue in the small control group used in Ithaca. The amount of information attainable from the assay will help immensely in the future of this pandemic, as being able to assess infection risks in population will save countless through precautions.
Guarino C, Larson E, Babasyan S, Rollins A, Joshi LR, Laverack M, et al. (2022) Development of a quantitative COVID-19 multiplex assay and its use for serological surveillance in a low SARS-CoV-2 incidence community. PLoS ONE 17(1): e0262868. https://doi.org/10.1371/journal.pone.0262868
A common strategy for nanomaterials to enter the cell has always been covalent coupling with cell-penetrating peptides (CPPs). While effective, it is not always desirable to make chemical modifications to the nanoparticles. Recently, cationic CPPs have been shown to stimulate cellular uptake of nanoparticles via co-administration. This effect, labeled the bystander manner, allows for nanoparticles to enter the cell with CPPs without chemical modification.
CPPs facilitate Nanoparticle entry into cells
Using CPPs synthesized by LifeTein, scientists wanted to explore if amphiphilic and hydrophobic CPPs were as effective as cationic CPPs at facilitating nanoparticles into the cell via the bystander manner. After testing the peptides used in the table above on mice, they found the amphiphilic Transportan Peptide (TP) was a very effective CPP for increasing cellular uptake of nanoparticles in this fashion.
Though more research needs to be completed down the line to fully understand all of the components of TP-mediated bystander uptake, this stands as a new and effective method to increase the intracellular delivery efficiency of nanoparticles.
Li, Y.-X.; Wei, Y.; Zhong, R.; Li, L.; Pang, H.-B. Transportan Peptide Stimulates the Nanomaterial Internalization into Mammalian Cells in the Bystander Manner through Macropinocytosis. Pharmaceutics 2021, 13, 552. https://doi.org/10.3390/pharmaceutics13040552
Expression of human endogenous retroviruses (HERVs) shows potential for peptide derivatives to be used as biomarkers for prostate cancer. Specifically, peptides from HERV-K and HERV-H Proteins show association in prostate cancer pathogenesis.
HERV Peptides as Biomarkers for Prostate Cancer
With prostate cancer being the most common cause of death by cancer in males, there is a need to identify aggressive tumors that current diagnostic tests do not measure up to. Scientists looked toward the envelope protein of HERV family viruses, well known for its immunosuppressive properties and role in modulating transcription factors of cancer-associated pathways. LifeTein synthesized the peptide derivatives of this protein, where HERV-K and HERV-H especially showed promise as prostate cancer biomarkers.
The findings suggest these HERV peptides have capabilities for their serum autoantibodies to further investigate the expression levels of the envelope protein of HERV-K and HERV-H in biopsy samples. It remains ever exciting to watch the continuously-growing usefulness of peptides expand into more and more fields, and hopefully use as Biomarkers is far from the last.
Manca, M.A.; Solinas, T.; Simula, E.R.; Noli, M.; Ruberto, S.; Madonia, M.; Sechi, L.A. HERV-K and HERV-H Env Proteins Induce a Humoral Response in Prostate Cancer Patients. Pathogens 2022, 11, 95. https://doi.org/10.3390/pathogens11010095
LifeTein was awarded the fastest peptide synthesis service in 2021 by New World Report, thanks to our speedy custom protein, antibody, and chemical services for biotech, pharma, academia, government customers, and diagnostics.
New World Report is an informative business news platform that covers businesses all throughout the Americas. Each year they honor the best of the best in their North America Business Elite awards, acknowledging the talent and accomplishments in businesses from any scale or field. Being recognized as the Fastest Peptide Synthesis Service is a tremendous honor for LifeTein.
LifeTein provides the fastest turnaround time and most reliable quality in the industry, using our proprietary microwave-assisted heating technology for peptide synthesis. The microwave can instantly heat any solvent or amino acids in solution through dipolar rotation or ionic conduction, resulting in a more efficient, more precise, and safer heating mode for peptide synthesis.
With LifeTein leading the way within this industry, you can expect us to continue the path of innovation at the same high quality we have always given.