bims-cepepe 2023-10-01 papers

bims-cepepe

Biomed News

on Cell-penetrating peptides

Issue of 2023–10–01
sixteen papers selected by
Henry Lamb, Queensland University of Technology

Molecular Dynamics Simulations of Drug-Conjugated Cell-Penetrating Peptides.
Peptide-Based Therapeutics in Cancer Therapy.
Talarolides Revisited: Cyclic Heptapeptides from an Australian Marine Tunicate-Associated Fungus, Talaromyces sp. CMB-TU011.
Therapeutic Peptide RF16 Derived from CXCL8 Inhibits MDA-MB-231 Cell Invasion and Metastasis.
An amide to thioamide substitution improves the permeability and bioavailability of macrocyclic peptides.
Macrocyclization strategies for the total synthesis of cyclic depsipeptides.
Rational Design of Novel Peptidomimetics against Influenza A Virus: Biological and Computational Studies.
Unnatural Amino Acid Engineering for Intracellular Delivery of Protein Therapeutics.
Regulatory T cells are associated with the tumor immune microenvironment and immunotherapy response in triple-negative breast cancer.
Progress in immune checkpoint inhibition in early-stage triple-negative breast cancer.
Identification of an Antimicrobial Peptide from the Venom of the Trinidad Thick-Tailed Scorpion Tityus trinitatis with Potent Activity against ESKAPE Pathogens and Clostridioides difficile.
Analgesic Effect of the Lysine-Containing Short Peptide Is Due to Modulation of the NaV1.8 Channel Activation Gating System.
PnPP-15, a Synthetic Peptide Derived from a Toxin from Phoneutria nigriventer Spider Venom, Alleviates Diabetic Neuropathic Pain and Acts Synergistically with Pregabalin in Mice.
Breaking the 'don't eat me' signal: in silico design of CD47-directed peptides for cancer immunotherapy.
Process intensification for the production of a C-tagged antimicrobial peptide in Escherichia coli - First steps toward a platform technology.
BRAF variant allele fraction-A predictor of response to targeted therapy?

Pharmaceuticals (Basel). 2023 Sep 05. pii: 1251. [Epub ahead of print]16(9):

Molecular Dynamics Simulations of Drug-Conjugated Cell-Penetrating Peptides.

Márton Ivánczi, Balázs Balogh, Loretta Kis, István Mándity.

  Cell-penetrating peptides (CPPs) are small peptides capable of translocating through biological membranes carrying various attached cargo into cells and even into the nucleus. They may also participate in transcellular transport. Our in silico study intends to model several peptides and their conjugates. We have selected three CPPs with a linear backbone, including penetratin, a naturally occurring oligopeptide; two of its modified sequence analogues (6,14-Phe-penetratin and dodeca-penetratin); and three natural CPPs with a cyclic backbone: Kalata B1, the Sunflower trypsin inhibitor 1 (SFT1), and Momordica cochinchinensis trypsin inhibitor II (MCoTI-II). We have also built conjugates with the small-molecule drug compounds doxorubicin, zidovudine, and rasagiline for each peptide. Molecular dynamics (MD) simulations were carried out with explicit membrane models. The analysis of the trajectories showed that the interaction of penetratin with the membrane led to spectacular rearrangements in the secondary structure of the peptide, while cyclic peptides remained unchanged due to their high conformational stability. Membrane-peptide and membrane-conjugate interactions have been identified and compared. Taking into account well-known examples from the literature, our simulations demonstrated the utility of computational methods for CPP complexes, and they may contribute to a better understanding of the mechanism of penetration, which could serve as the basis for delivering conjugated drug molecules to their intracellular targets.

Keywords:  Desmond; biological membrane; cell-penetrating peptides; cyclic peptides; drug conjugates; explicit membrane model; in silico simulation; intracellular target; molecular dynamics; penetratin

DOI:  https://doi.org/10.3390/ph16091251
Mol Biotechnol. 2023 Sep 28.

Peptide-Based Therapeutics in Cancer Therapy.

Abduladheem Turki Jalil, Mohanad Ali Abdulhadi, Lubna R Al-Ameer, Waam Mohammed Taher, Sada Jasim Abdulameer, Munther Abosaooda, Ali A Fadhil.

  A monster called cancer is still one of the most challenging human problems and one of the leading causes of death in the world. Different types of treatment methods are used for cancer therapy; however, there are challenges such as high cost and harmful side effects in using these methods. Recent years have witnessed a surge in the development of therapeutic peptides for a wide range of diseases, notably cancer. Peptides are preferred over antibiotics, radiation therapy, and chemotherapy in the treatment of cancer due to a number of aspects, including flexibility, easy modification, low immunogenicity, and inexpensive cost of production. The use of therapeutic peptides in cancer treatment is a novel and intriguing strategy. These peptides provide excellent prospects for targeted drug delivery because of their high selectivity, specificity, small dimensions, good biocompatibility, and simplicity of modification. Target specificity and minimal toxicity are benefits of therapeutic peptides. Additionally, peptides can be used to design antigens or adjuvants for vaccine development. Here, types of therapeutic peptides for cancer therapy will be discussed, such as peptide-based cancer vaccines and tumor-targeting peptides (TTP) and cell-penetrating peptides (CPP).

Keywords:  Cancer; Drug delivery; Peptide Vaccine; Therapeutic peptides

DOI:  https://doi.org/10.1007/s12033-023-00873-1
Mar Drugs. 2023 Sep 11. pii: 487. [Epub ahead of print]21(9):

Talarolides Revisited: Cyclic Heptapeptides from an Australian Marine Tunicate-Associated Fungus, Talaromyces sp. CMB-TU011.

Angela A Salim, Waleed M Hussein, Pradeep Dewapriya, Huy N Hoang, Yahao Zhou, Kaumadi Samarasekera, Zeinab G Khalil, David P Fairlie, Robert J Capon.

  Application of a miniaturized 24-well plate system for cultivation profiling (MATRIX) permitted optimization of the cultivation conditions for the marine-derived fungus Talaromyces sp. CMB-TU011, facilitating access to the rare cycloheptapeptide talarolide A (1) along with three new analogues, B-D (2-4). Detailed spectroscopic analysis supported by Marfey's analysis methodology was refined to resolve N-Me-l-Ala from N-Me-d-Ala, l-allo-Ile from l-Ile and l-Leu, and partial and total syntheses of 2, and permitted unambiguous assignment of structures for 1 (revised) and 2-4. Consideration of diagnostic ROESY correlations for the hydroxamates 1 and 3-4, and a calculated solution structure for 1, revealed how cross-ring H-bonding to the hydroxamate moiety influences (defines/stabilizes) the cyclic peptide conformation. Such knowledge draws attention to the prospect that hydroxamates may be used as molecular bridges to access new cyclic peptide conformations, offering the prospect of new biological properties, including enhanced oral bioavailability.

Keywords:  GNPS molecular networking; MATRIX; N-OH glycine; Talaromyces; cycloheptapeptide; talarolides

DOI:  https://doi.org/10.3390/md21090487
Int J Mol Sci. 2023 Sep 13. pii: 14029. [Epub ahead of print]24(18):

Therapeutic Peptide RF16 Derived from CXCL8 Inhibits MDA-MB-231 Cell Invasion and Metastasis.

Chun-Ming Chang, Chun-Chun Chang, Ho Yin Pekkle Lam, Shih-Yi Peng, Yi-Hsuan Lai, Bi-Da Hsiang, Yu-Yi Liao, Hao-Jen Hsu, Shinn-Jong Jiang.

  Interleukin (IL)-8 plays a vital role in regulating inflammation and breast cancer formation by activating CXCR1/2. We previously designed an antagonist peptide, (RF16), to inhibits the activation of downstream signaling pathways by competing with IL-8 in binding to CXCR1/2, thereby inhibiting IL-8-induced chemoattractant monocyte binding. To evaluate the effect of the RF16 peptide on breast cancer progression, triple-negative MDA-MB-231 and ER-positive MCF-7 breast cancer cells were used to investigate whether RF16 can inhibit the IL-8-induced breast cancer metastasis. Using growth, proliferation, and invasiveness assays, the results revealed that RF16 reduced cell proliferation, migration, and invasiveness in MDA-MB-231 cells. The RF16 peptide also regulated the protein and mRNA expressions of epithelial-mesenchymal transition (EMT) markers in IL-8-stimulated MDA-MB-231 cells. It also inhibited downstream IL-8 signaling and the IL-8-induced inflammatory response via the mitogen-activated protein kinase (MAPK) and Phosphoinositide 3-kinase (PI3K) pathways. In the xenograft tumor mouse model, RF16 synergistically reinforces the antitumor efficacy of docetaxel by improving mouse survival and retarding tumor growth. Our results indicate that RF16 significantly inhibited IL-8-stimulated cell growth, migration, and invasion in MDA-MB-231 breast cancer cells by blocking the activation of p38 and AKT cascades. It indicated that the RF16 peptide may serve as a new supplementary drug for breast cancer.

Keywords:  IL-8; breast cancer; cell proliferation; invasiveness; metastasis; peptide drugs

DOI:  https://doi.org/10.3390/ijms241814029
Nat Commun. 2023 Sep 28. 14(1): 6050

An amide to thioamide substitution improves the permeability and bioavailability of macrocyclic peptides.

Pritha Ghosh, Nishant Raj, Hitesh Verma, Monika Patel, Sohini Chakraborti, Bhavesh Khatri, Chandrashekar M Doreswamy, S R Anandakumar, Srinivas Seekallu, M B Dinesh, Gajanan Jadhav, Prem Narayan Yadav, Jayanta Chatterjee.

Solvent shielding of the amide hydrogen bond donor (NH groups) through chemical modification or conformational control has been successfully utilized to impart membrane permeability to macrocyclic peptides. We demonstrate that passive membrane permeability can also be conferred by masking the amide hydrogen bond acceptor (>C = O) through a thioamide substitution (>C = S). The membrane permeability is a consequence of the lower desolvation penalty of the macrocycle resulting from a concerted effect of conformational restriction, local desolvation of the thioamide bond, and solvent shielding of the amide NH groups. The enhanced permeability and metabolic stability on thioamidation improve the bioavailability of a macrocyclic peptide composed of hydrophobic amino acids when administered through the oral route in rats. Thioamidation of a bioactive macrocyclic peptide composed of polar amino acids results in analogs with longer duration of action in rats when delivered subcutaneously. These results highlight the potential of O to S substitution as a stable backbone modification in improving the pharmacological properties of peptide macrocycles.

DOI: https://doi.org/10.1038/s41467-023-41748-y
Org Biomol Chem. 2023 Sep 26.

Macrocyclization strategies for the total synthesis of cyclic depsipeptides.

André R Paquette, Christopher N Boddy.

Cyclic depsipeptides are an important class of peptide natural products that are defined by the presence of ester and amide bonds within the macrocycle. The structural diversity of depsipeptides has required the development of a broad range of synthetic strategies to access these biologically active compounds. Solid phase peptide synthesis (SPPS) strategies have been an invaluable tool in their synthesis. The key aspect of their synthesis is the macrocyclization strategy. Three main strategies are used, solution phase macrolactamization of acyclic ester containing peptide, on-resin macrolactamization of a sidechain-anchored peptide, and the solution phase macrolactonization of a linear peptide. Additionally, biocatalysts have been used to produce these compounds in a regio- and chemo-selective manner. Each compound offers unique challenges, requiring careful synthetic design to avoid undesirable side reactivity or unwanted epimerization during the esterification and macrocyclizing steps. This focused review analyzes these three strategies for cyclic depsipeptide natural product total synthesis with selected examples from the literature between 2001-2023.

DOI: https://doi.org/10.1039/d3ob01229h
Int J Mol Sci. 2023 Sep 19. pii: 14268. [Epub ahead of print]24(18):

Rational Design of Novel Peptidomimetics against Influenza A Virus: Biological and Computational Studies.

Maria Carmina Scala, Magda Marchetti, Fabiana Superti, Mariangela Agamennone, Pietro Campiglia, Marina Sala.

  Effective therapy against the influenza virus is still an unmet goal. Drugs with antiviral effects exist, but the appearance of resistant viruses pushes towards the discovery of drugs with different mechanisms of action. New anti-influenza molecules should target a good candidate, as a new anti-influenza molecule could be an inhibitor of the influenza A virus hemagglutinin (HA), which plays a key role during the early phases of infection. In previous work, we identified two tetrapeptide sequences, SLDC (1) and SKHS (2), derived from bovine lactoferrin (bLf) C-lobe fragment 418-429, which were able to bind HA and inhibit cell infection at picomolar concentration. Considering the above, the aim of this study was to synthesize a new library of peptidomimetics active against the influenza virus. In order to test their ability to bind HA, we carried out a preliminary screening using biophysical assays such as surface plasmon resonance (SPR) and orthogonal immobilization-free microscale thermophoresis (MST). Biological and computational studies on the most interesting compounds were carried out. The methods applied allowed for the identification of a N-methyl peptide, S(N-Me)LDC, which, through high affinity binding of influenza virus hemagglutinin, was able to inhibit virus-induced hemagglutination and cell infection at picomolar concentration. This small sequence, with high activity, represents a good starting point for the design of new peptidomimetics and small molecules.

Keywords:  biophysical assay; docking; hemagglutinin; influenza; peptidomimetic

DOI:  https://doi.org/10.3390/ijms241814268
Methods Mol Biol. 2024 ;2720 151-164

Unnatural Amino Acid Engineering for Intracellular Delivery of Protein Therapeutics.

Wilfred Chen, Millicent O Sullivan.

  Protein drugs are a critically important therapeutic modality due to the sophisticated binding recognition, catalytic properties, and disease relevance of proteins. There is a clear need for new strategies able to improve pharmacokinetics, bioavailability, and/or intracellular delivery of therapeutic proteins, as stability limitations have significantly hindered clinical advancement, and most proteins are membrane impermeable. Bioconjugation strategies able to site-specifically modify proteins with cell binding, and other ligands offer a particularly valuable approach to facilitate protein delivery due to the importance of ligand presentation on protein bioactivity and cellular uptake. We explored unnatural amino acid (UAA) incorporation as a novel strategy to tunably incorporate clustered cell-binding ligands in fluorescent proteins and suicide enzymes, resulting in substantial increases in cell-specific uptake and targeted cell-killing activity. These approaches offer a valuable and versatile method to modify a variety of proteins and enable improved clinical potential.

Keywords:  EGFR; Endosomolytic peptide; Prodrug; Synthetic biology; Unnatural amino acid (UAA)

DOI:  https://doi.org/10.1007/978-1-0716-3469-1_11
Front Immunol. 2023 ;14 1263537

Regulatory T cells are associated with the tumor immune microenvironment and immunotherapy response in triple-negative breast cancer.

Pengfei Huang, Xinyue Zhou, Minying Zheng, Yongjun Yu, Gongsheng Jin, Shiwu Zhang.

   Introduction: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with a high risk of distant metastasis, an extremely poor prognosis, and a high risk of death. Regulatory T cells (Tregs) contribute to the formation of a tumor immunosuppressive microenvironment, which plays an important role in the progression and treatment resistance of TNBC.
Methods: A public single-cell sequencing dataset demonstrated increased infiltration of Tregs in TNBC tissues relative to normal breast tissue. Weighted gene co-expression network analysis was used to identify Treg infiltration-related modules for METABRIC TNBC samples. Subsequently, we obtained two Treg infiltration-associated clusters of TNBC by applying consensus clustering and further constructed a prognostic model based on this Treg infiltration-associated gene module. The ability of the selected gene in the prognostic model, thymidine kinase-1 (TK1), to promote the progression of TNBC was evaluated in vitro.
Results: We concluded that two Treg infiltration-associated clusters had different prognoses and sensitivities to drugs commonly used in breast cancer treatment, and multi-omics analysis revealed that the two clusters had different copy number variations of key tumor progression genes. The 7-gene risk score based on TNBC Treg infiltration was a reliable prognostic indicator both in the training and validation cohorts. Moreover, patients with TNBC with high Treg infiltration-related scores lacked the activation of immune activation pathways and exhibited resistance to anti-PD1 immunotherapy. Knocking down TK1 led to impaired proliferation, migration, and invasion of TNBC cells in vitro. In addition, specimens from patients with TNBC with high TK1 expression showed significantly higher Treg infiltration in tumors. Results of spatial transcriptome analysis showed that TK1 positive cells mainly localize in tumor area, and Treg cell infiltration in TNBC tissues was associated with high expression of TK1. Pan-cancer analysis also demonstrated that TK1 is associated with poor prognosis and activation of proliferation pathways in multiple cancers.
Discussion: We established a prognostic model related to Treg infiltration and this model can be used to establish a clinically relevant classification of TNBC progression. Additionally, our work revealed the underestimable potential of TK1 as a tumor biomarker and immunotherapeutic target.

Keywords:  prognostic signature; regulatory T cells; single-cell RNA-sequencing; triple-negative breast cancer; tumor microenvironment

DOI:  https://doi.org/10.3389/fimmu.2023.1263537
Expert Rev Anticancer Ther. 2023 Sep 25.

Progress in immune checkpoint inhibition in early-stage triple-negative breast cancer.

Ahmed Mohamed, Megan Kruse, Jennifer Tran.

   INTRODUCTION: Immune checkpoint inhibitors have been particularly effective in treating cancers with robust immune microenvironments and have been successfully incorporated into the management of metastatic ER-negative, HER2-negative breast cancer. This has prompted investigation of immunotherapy in early-stage triple negative breast cancer (TNBC) to address the suboptimal clinical outcomes and limited therapeutic options.
AREAS COVERED: This review highlights the studies examining the use of neoadjuvant immunotherapy with standard chemotherapy in the management of early-stage TNBC as well as ongoing areas of study including the role of checkpoint inhibition in the adjuvant setting and novel combination therapies with immunotherapy.
EXPERT OPINION: At present, the current standard of care for women with early-stage ER-negative, HER2-negative breast cancer measuring ≥2 cm or with lymph node involvement is neoadjuvant chemotherapy with pembrolizumab followed by ongoing pembrolizumab in the adjuvant setting to complete 1 year of total therapy as per the KEYNOTE-522 study. This approach is associated with improved pathologic complete response (pCR) rate as well as improved event free survival. These improvements in disease management occur regardless of PD-L1 status. Many questions remain regarding the optimization of chemotherapy partner(s) for immunotherapy, necessity of adjuvant immunotherapy for patients who achieve pCR, inclusion of other therapies in the adjuvant setting (particularly capecitabine or olaparib), and use of adjuvant immunotherapy when it was not received in the neoadjuvant setting.

Keywords:  CTLA-4 inhibitors; PD-L1/PD1 inhibitors; Triple negative breast cancer; early-stage breast cancer; immune checkpoint inhibitors; immunotherapy

DOI:  https://doi.org/10.1080/14737140.2023.2262764
Antibiotics (Basel). 2023 Sep 04. pii: 1404. [Epub ahead of print]12(9):

Identification of an Antimicrobial Peptide from the Venom of the Trinidad Thick-Tailed Scorpion Tityus trinitatis with Potent Activity against ESKAPE Pathogens and Clostridioides difficile.

Milena Mechkarska, Taylor S Cunning, Megan G Taggart, Nigel G Ternan, Jérôme Leprince, Laurent Coquet, Thierry Jouenne, Jordi Tena-Garcés, Juan J Calvete, J Michael Conlon.

  Envenomation by the Trinidad thick-tailed scorpion Tityus trinitatis may result in fatal myocarditis and there is a high incidence of acute pancreatitis among survivors. Peptidomic analysis (reversed-phase HPLC followed by MALDI-TOF mass spectrometry and automated Edman degradation) of T. trinitatis venom led to the isolation and characterization of three peptides with antimicrobial activity. Their primary structures were established asTtAP-1 (FLGSLFSIGSKLLPGVFKLFSRKKQ.NH2), TtAP-2 (IFGMIPGLIGGLISAFK.NH2) and TtAP-3 (FFSLIPSLIGGLVSAIK.NH2). In addition, potassium channel and sodium channel toxins, present in the venom in high abundance, were identified by CID-MS/MS sequence analysis. TtAP-1 was the most potent against a range of clinically relevant Gram-positive and Gram-negative aerobes and against the anaerobe Clostridioides difficile (MIC = 3.1-12.5 µg/mL). At a concentration of 1× MIC, TtAP-1 produced rapid cell death (<15 min against Acinetobacter baumannii and Staphylococcus aureus). The therapeutic potential of TtAP-1 as an anti-infective agent is limited by its high hemolytic activity (LC50 = 18 µg/mL against mouse erythrocytes) but the peptide constitutes a template for the design of analogs that maintain the high bactericidal activity against ESKAPE pathogens but are less toxic to human cells. It is suggested that the antimicrobial peptides in the scorpion venom facilitate the action of the neurotoxins by increasing the membrane permeability of cells from either prey or predator.

Keywords:  Clostridioides difficile; ESKAPE pathogen; antimicrobial peptide; neurotoxin; scorpion venom

DOI:  https://doi.org/10.3390/antibiotics12091404
Life (Basel). 2023 Aug 24. pii: 1800. [Epub ahead of print]13(9):

Analgesic Effect of the Lysine-Containing Short Peptide Is Due to Modulation of the NaV1.8 Channel Activation Gating System.

Arina D Kalinina, Ilya V Rogachevskii, Dmitriy M Samosvat, Georgy G Zegrya, Irina P Butkevich, Viktor A Mikhailenko, Vera B Plakhova, Valentina A Penniyaynen, Svetlana A Podzorova, Boris V Krylov.

  The present work continues our recent series of articles that aim to elucidate the ligand-receptor binding mechanism of short cationic peptides to the NaV1.8 channel in the nociceptive neuron. The applied methodological approach has involved several methods: the patch-clamp experimental evaluation of the effective charge of the NaV1.8 channel activation gating system, the organotypic tissue culture method, the formalin test, and theoretical conformational analysis. The lysine-containing short peptide Ac-KEKK-NH2 has been shown to effectively modulate the NaV1.8 channel activation gating system. As demonstrated by the organotypic tissue culture method, the studied short peptide does not trigger the downstream signaling cascades controlling neurite outgrowth and should not be expected to evoke adverse side effects. Conformational analysis of the Ac-KEKK-NH2 molecule has revealed that the distances between the positively charged amino groups of the lysine side chains are equal to 11-12 Å. According to the previously suggested mechanism of ligand-receptor binding of short peptides to the NaV1.8 channel molecule, Ac-KEKK-NH2 should exhibit an analgesic effect, which has been confirmed by the formalin test. The data obtained unequivocally indicate that the studied lysine-containing short peptide is a promising candidate for the role of a novel analgesic medicinal substance.

Keywords:  NaV1.8 channel; analgesics; conformational analysis; formalin test; lysine-containing peptides; nociception; organotypic tissue culture method; patch-clamp method

DOI:  https://doi.org/10.3390/life13091800
Toxins (Basel). 2023 Sep 07. pii: 560. [Epub ahead of print]15(9):

PnPP-15, a Synthetic Peptide Derived from a Toxin from Phoneutria nigriventer Spider Venom, Alleviates Diabetic Neuropathic Pain and Acts Synergistically with Pregabalin in Mice.

Xavier Maia Mariano, Luana Caroline de Assis Ferreira, Camila Megale Almeida-Leite, Célio José de Castro Junior, Maria Elena de Lima.

  Diabetic neuropathic pain is one of the complications that affect a wide variety of the diabetic population and is often difficult to treat. Only a small number of patients experience pain relief, which usually comes with onerous side effects and low levels of satisfaction. The search for new analgesic drugs is necessary, given the limitations that current drugs present. Combining drugs to treat neuropathic pain has been attracting interest to improve their efficacy compared to single-drug monotherapies while also reducing dose sizes to minimize side effects. The aim of our study was to verify the antinociceptive effect of a synthetic peptide, PnPP-15, alone and combined with pregabalin, in male Swiss diabetic mice using the von Frey method. PnPP-15 is a synthetic peptide derived from PnPP19, a peptide representing a discontinuous epitope of the primary structure of the toxin PnTx2-6 from the venom of the spider Phoneutria nigriventer. The antinociceptive activity of both compounds was dose-dependent and showed synergism, which was verified by isobolographic analysis. Treatment with PnPP-15 did not cause spontaneous or forced motor changes and did not cause any damage or signs of toxicity in the analyzed organs (pancreas, lung, heart, kidney, brain, or liver). In conclusion, PnPP-15 is a great candidate for an analgesic drug against neuropathic pain caused by diabetes and exerts a synergistic effect when combined with pregabalin, allowing for even more efficient treatment.

Keywords:  Phoneutria nigriventer spider; PnPP-15 peptide; antinociception; neuropatic pain in diabetes; pregabalin

DOI:  https://doi.org/10.3390/toxins15090560
Mol Divers. 2023 Sep 28.

Breaking the 'don't eat me' signal: in silico design of CD47-directed peptides for cancer immunotherapy.

Kapil Laddha, M Elizabeth Sobhia.

  The leading cause of death worldwide is cancer. Although there are various therapies available to treat cancer, finding a successful one can be like searching for a needle in a haystack. Immunotherapy appears to be one of those needles in the haystack of cancer treatment. Immunotherapeutic agents enhance the immune response of the patient's body to tumor cells. One of the immunotherapeutic targets, Cluster of Differentiation 47 (CD47), releases the "don't eat me" signal when it binds to its receptor, Signal Regulatory Protein (SIRPα). Tumor cells use this signal to circumvent the immune system, rendering it ineffective. To stop tumor cells from releasing the "don't eat me" signal, the CD47-SIRPα interaction is specifically targeted in this study. To do so, in silico peptides were designed based on the structural analysis of the interaction between two proteins using point mutations on the interacting residues with the other amino acids. The peptide library was designed and docked on SIRPα using computational tools. Later on, after analyzing the docked complex, the best of them was selected for MD simulation studies of 100 ns. Further analysis after MD studies was carried out to determine the possible potential anti-SIRPα peptides.

Keywords:  CD47/SIRPα; Cancer; Don’t eat me signal; Immunotherapy; Peptide library; Protein-peptide docking

DOI:  https://doi.org/10.1007/s11030-023-10732-5
J Biosci Bioeng. 2023 Sep 26. pii: S1389-1723(23)00298-0. [Epub ahead of print]

Process intensification for the production of a C-tagged antimicrobial peptide in Escherichia coli - First steps toward a platform technology.

Carolin A Lappöhn, Arne M Oestreich, Robin Stei, Linus G Weber, Lea Maerz, Michael W Wolff.

  The production of antimicrobial peptides/proteins (AMPs) in sufficient quantities for clinical evaluation is challenging because complex peptides are unsuitable for chemical synthesis, natural sources have low yields, and heterologous systems often have low expression levels or require product-specific process adaptations. Here we describe the production of a complex AMP, the insect metalloproteinase inhibitor (IMPI), by adding a C-terminal C-tag to increase the yield compared to the unmodified peptide. We used a design of experiments approach for process intensification in Escherichia coli Rosetta-gami 2(DE3)pLysS cells and achieved a yield of 260 mg L-1, which is up to 30-fold higher than previously reported. The C-tag also enhanced product purity but had no effect on IMPI activity, making tag removal unnecessary and therefore simplifying process analytics and downstream processing. We have confirmed that the C-tag is compatible with the peptide and could form the basis of a platform technology for the expression, purification and detection of diverse AMPs produced in E. coli.

Keywords:  Antimicrobial peptide/protein; C-tag; Escherichia coli; Insect metalloproteinase inhibitor; Recombinant peptide; Small molecular fusion tag

DOI:  https://doi.org/10.1016/j.jbiosc.2023.09.003
J Eur Acad Dermatol Venereol. 2023 10;37(10): 1945-1946

BRAF variant allele fraction-A predictor of response to targeted therapy?

Mitchell S Stark, Teresa Harris, Douglas Grossman, Robert Judson-Torres.

DOI: https://doi.org/10.1111/jdv.19389