bims-cepepe 2024-04-14 papers

bims-cepepe

Biomed News

on Cell-penetrating peptides

Issue of 2024‒04‒14
sixteen papers selected by
Henry Lamb, Queensland University of Technology

A QUANTITATIVE METHOD TO DISTINGUISH CYTOSOLIC FROM ENDOSOME-TRAPPED CELL-PENETRATING PEPTIDES.
Large Libraries of Structurally Diverse Macrocycles Suitable for Membrane Permeation.
A Stapled Peptide Inhibitor Targeting the Binding Interface of N6-Adenosine-Methyltransferase Subunits METTL3 and METTL14 for Cancer Therapy.
Correction to "Structural Elucidation of the Cell-Penetrating Penetratin Peptide in Model Membranes at the Atomic Level: Probing Hydrophobic Interactions in the Blood-Brain Barrier".
Design and Synthesis of Novel Ultralong-Acting Peptides as EDP-EBP Interaction Inhibitors for Pulmonary Fibrosis Treatment.
Peptide-drug conjugate designated for targeted delivery to HER2-expressing cancer cells.
Discovery of TNG908: A Selective, Brain Penetrant, MTA-Cooperative PRMT5 Inhibitor That Is Synthetically Lethal with MTAP-Deleted Cancers.
BDNF- and VEGF-Responsive Stimulus to an NGF Mimic Cyclic Peptide with Copper Ionophore Capability and Ctr1/CCS-Driven Signaling.
Preclinical efficacy of a PSMA-targeted actinium-225 conjugate (225Ac-macropa-pelgifatamab) - a targeted alpha therapy for prostate cancer.
TAS3681, an androgen receptor antagonist, prevents drug resistance driven by aberrant androgen receptor signaling in prostate cancer.
A modular and synthetic biosynthesis platform for de novo production of diverse halogenated tryptophan-derived molecules.
Recent Progress in the Oral Delivery of Therapeutic Peptides and Proteins: Overview of Pharmaceutical Strategies to Overcome Absorption Hurdles.
Design and Preclinical Evaluation of a Novel Prostate-Specific Membrane Antigen Radioligand Modified with a Transthyretin Binder.
Development and in-depth characterization of BRAFi-resistant melanoma cell lines in vitro and in vivo.
Correction to: Introducing π-HelixNovo for practical large-scale de novo peptide sequencing.
Discovery of novel macrocyclic derivatives as potent and selective cyclin-dependent kinase 2 inhibitors.

Chembiochem. 2024 Apr 08. e202400198

A QUANTITATIVE METHOD TO DISTINGUISH CYTOSOLIC FROM ENDOSOME-TRAPPED CELL-PENETRATING PEPTIDES.

Françoise Illien, Zoltán Bánóczi, Sandrine Sagan.

  Cell-penetrating peptides are known to penetrate cells through endocytosis and translocation. The two pathways are hardly distinguished in current cell assays. We developed a reliable, simple and robust method to distinguish and quantify independently the two routes. The assay requires (DABCYL) 4-(dimethylaminoazo)benzene-4-carboxylic acid- and (CF) carboxyfluorescein-labeled peptides. When the labeled peptide is intact, the fluorescence signal is weak thanks to the dark quenching property of DABCYL. A 10-fold higher fluorescence signal is measured when the labeled peptide is degraded. By referring to a standard fluorescent curve according to the concentration of the hydrolyzed peptide, we have access to the internalized peptide quantity. Therefore, cell lysis after internalization permits to determine the total quantity of intracellular peptide. The molecular state of the internalized peptide (intact or degraded), depends on its location in cells (cytosol vs endo-lysosomes), and can be blocked by boiling cells. This boiling step results indeed in denaturation and inhibition of the cellular enzymes. The advantage of this method is the possibility to quantify translocation at 37°C and to compare it to the 4°C condition, where all endocytosis processes are inhibited. We found that ranking of the translocation efficacy is DABCYL-R6-(εCF)K >> DABCYL-R4-(εCF)K ≥ CF-R9.

Keywords:  37°C translocation; Cell-Penetrating Peptide; fluorescence; internalization; quantitative measurement

DOI:  https://doi.org/10.1002/cbic.202400198
Angew Chem Int Ed Engl. 2024 Apr 11. e202400350

Large Libraries of Structurally Diverse Macrocycles Suitable for Membrane Permeation.

Alexander L Nielsen, Zsolt Bognar, Ganesh K Mothukuri, Anne Zarda, Mischa Schuttel, Manuel L Merz, Xinjian Ji, Edward Will, Monica Chinellato, Christian R O Bartling, Kristian Stromgaard, Laura Cendron, Alessandro Angelini, Christian Heinis.

  Macrocycles offer an attractive format for drug development due to their good binding properties and potential to cross cell membranes. To efficiently identify macrocyclic ligands for new targets, methods for the synthesis and screening of large combinatorial libraries of small cyclic peptides were developed, many of them using thiol groups for efficient peptide macrocyclization. However, a weakness of these libraries is that invariant thiol-containing building blocks such as cysteine are used, resulting in a region that does not contribute to library diversity but increases molecule size. Herein, we synthesized a series of structurally diverse thiol-containing elements and used them for the combinatorial synthesis of a 2,688-member library of small, structurally diverse peptidic macrocycles with unprecedented skeletal complexity. We then used this library to discover potent thrombin and plasma kallikrein inhibitors, some also demonstrating favorable membrane permeability. X-ray structure analysis of macrocycle-target complexes showed that the size and shape of the newly developed thiol elements are key for binding. The strategy and library format presented in this work significantly enhance structural diversity by allowing combinatorial modifications to a previously invariant region of peptide macrocycles, which may be broadly applied in the development of membrane permeable therapeutics.

Keywords:  cell permeability, cyclization, high-throughput screening, macrocycle, protease inhibitor

DOI:  https://doi.org/10.1002/anie.202400350
Angew Chem Int Ed Engl. 2024 Apr 12. e202402611

A Stapled Peptide Inhibitor Targeting the Binding Interface of N6-Adenosine-Methyltransferase Subunits METTL3 and METTL14 for Cancer Therapy.

Zenghui Li, Yuqing Feng, Hong Han, Xingyue Jiang, Weiyu Chen, Xuezhen Ma, Yang Mei, Dan Yuan, Dingxiao Zhang, Junfeng Shi.

  METTL3, a primary methyltransferase catalyzing RNA N6-methyladenosine (m6A) modification, has been identified as an oncogene in several cancer types and thus nominated as a potentially effective target for therapeutic inhibition, although current options using this strategy are limited. In this study, we targeted protein-protein interactions at the METTL3-METTL14 binding interface to inhibit complex formation and subsequent catalysis of RNA m6A modification. Among candidate peptides, RM3 exhibited the highest anti-cancer potency, inhibiting METTL3 activity while also facilitating its proteasomal degradation. We then designed a stapled peptide inhibitor (RSM3) with enhanced peptide stability and formation of the α-helical secondary structure required for METTL3 interaction. Functional and transcriptomic analysis in vivo indicated that RSM3 induced upregulation of programmed cell death-related genes while inhibiting cancer-promoting signals. Furthermore, tumor growth was significantly suppressed while apoptosis was enhanced upon RSM3 treatment, accompanied by in-creased METTL3 degradation, and reduced global RNA methylation levels in two in vivo tumor models. This peptide inhibitor thus exploits a mechanism distinct from other competitive-binding small molecules to inhibit oncogenic METTL3 activity. Our findings collectively highlight the potential of targeting METTL3 in cancer therapies through peptide-based inhibition of complex formation and proteolytic degradation.

Keywords:  Peptide drug * Inhibitor * Cancer* Staple peptide * METTL3

DOI:  https://doi.org/10.1002/anie.202402611
Biochemistry. 2024 Apr 10.

Correction to "Structural Elucidation of the Cell-Penetrating Penetratin Peptide in Model Membranes at the Atomic Level: Probing Hydrophobic Interactions in the Blood-Brain Barrier".

Swapna Bera, Rajiv K Kar, Susanta Mondal, Kalipada Pahan, Anirban Bhunia.

DOI: https://doi.org/10.1021/acs.biochem.4c00118
J Med Chem. 2024 Apr 08.

Design and Synthesis of Novel Ultralong-Acting Peptides as EDP-EBP Interaction Inhibitors for Pulmonary Fibrosis Treatment.

Yixiang Wang, Fanghan Xue, Wei Cheng, Qian Zhao, Nazi Song, Zihan Shi, Han Liu, Yu Li, Qinglin Tang, Qi Liu, Yiqing Wang, Fangfang Zhang, Xianxing Jiang.

The increased remodeling of the extracellular matrix (ECM) in pulmonary fibrosis (PF) generates bioactive ECM fragments called matricryptins, which include elastin-derived peptides (EDPs). The interaction between EDPs and their receptors, including elastin-binding protein (EBP), plays a crucial role in exacerbating fibrosis. Here, we present LXJ-02 for the first time, a novel ultralong-acting inhibitor that disrupts the EDPs/EBP peptide-protein interaction, promoting macrophages to secrete matrix metalloproteinase-12 (MMP-12), and showing great promise as a stable peptide. MMP-12 has traditionally been implicated in promoting inflammation and fibrosis in various acute and chronic diseases. However, we reveal a novel role of LXJ-02 that activates the macrophage-MMP-12 axis to increase MMP-12 expression and degrade ECM components like elastin. This leads to the preventing of PF while also improving EDP-EBP interaction. LXJ-02 effectively reverses PF in mouse models with minimal side effects, holding great promise as an excellent therapeutic agent for lung fibrosis.

DOI: https://doi.org/10.1021/acs.jmedchem.4c00067
J Pept Sci. 2024 Apr 10. e3602

Peptide-drug conjugate designated for targeted delivery to HER2-expressing cancer cells.

Amit Kumar Sharma, Rohit Sharma, Nitish Chauhan, Amit Das, Drishty Satpati.

  Targeted therapy of the highest globally incident breast cancer shall resolve the issue of off-target toxicity concurring with augmented killing of specific diseased cells. Thus, the goal of this study was to prepare a peptide-drug conjugate targeting elevated expression of HER2 receptors in breast cancer. Towards this, the rL-A9 peptide was conjugated with the chemotherapeutic drug doxorubicin (DOX) through a N-succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker. The synthesized peptide-drug conjugate, rL-A9-DOX, was characterized by mass spectrometry. Molecular docking studies, based on binding energy data, suggested a stronger interaction of rL-A9-DOX with the HER2 receptor in comparison to the unconjugated peptide, rL-A9. The cytotoxic effect of the rL-A9-DOX conjugate was observed to be higher in HER2-positive SKOV3 cells compared to HER2-negative MDA-MB-231 cells, indicating selective cell killing. Cellular internalization of the rL-A9-DOX conjugate was evident from the flow cytometry analysis, where a noticeable shift in mean fluorescent intensity (MFI) was observed for the conjugate compared to the control group. This data was further validated by confocal microscopy, where the fluorescent signal ascertained nuclear accumulation of rL-A9-DOX. The present studies highlight the promising potential of rL-A9-DOX for targeted delivery of the drug into a defined group of cancer cells.

Keywords:  HER2; cytotoxicity; doxorubicin; peptide‐drug conjugate; rL‐A9

DOI:  https://doi.org/10.1002/psc.3602
J Med Chem. 2024 Apr 10.

Discovery of TNG908: A Selective, Brain Penetrant, MTA-Cooperative PRMT5 Inhibitor That Is Synthetically Lethal with MTAP-Deleted Cancers.

Kevin M Cottrell, Kimberly J Briggs, Douglas A Whittington, Haris Jahic, Janid A Ali, Charles B Davis, Shanzhong Gong, Deepali Gotur, Lina Gu, Patrick McCarren, Matthew R Tonini, Alice Tsai, Erik W Wilker, Hongling Yuan, Minjie Zhang, Wenhai Zhang, Alan Huang, John P Maxwell.

It has been shown that PRMT5 inhibition by small molecules can selectively kill cancer cells with homozygous deletion of the MTAP gene if the inhibitors can leverage the consequence of MTAP deletion, namely, accumulation of the MTAP substrate MTA. Herein, we describe the discovery of TNG908, a potent inhibitor that binds the PRMT5·MTA complex, leading to 15-fold-selective killing of MTAP-deleted (MTAP-null) cells compared to MTAPintact (MTAP WT) cells. TNG908 shows selective antitumor activity when dosed orally in mouse xenograft models, and its physicochemical properties are amenable for crossing the blood-brain barrier (BBB), supporting clinical study for the treatment of both CNS and non-CNS tumors with MTAP loss.

DOI: https://doi.org/10.1021/acs.jmedchem.4c00133
ACS Chem Neurosci. 2024 Apr 11.

BDNF- and VEGF-Responsive Stimulus to an NGF Mimic Cyclic Peptide with Copper Ionophore Capability and Ctr1/CCS-Driven Signaling.

Barbara Tomasello, Francesco Bellia, Irina Naletova, Antonio Magrì, Giovanni Tabbì, Francesco Attanasio, Marianna Flora Tomasello, Warren R L Cairns, Mariagrazia Fortino, Adriana Pietropaolo, Valentina Greco, Diego La Mendola, Sebastiano Sciuto, Giuseppe Arena, Enrico Rizzarelli.

  Neurotrophins are a family of growth factors that play a key role in the development and regulation of the functioning of the central nervous system. Their use as drugs is made difficult by their poor stability, cellular permeability, and side effects. Continuing our effort to use peptides that mimic the neurotrophic growth factor (NGF), the family model protein, and specifically the N-terminus of the protein, here we report on the spectroscopic characterization and resistance to hydrolysis of the 14-membered cyclic peptide reproducing the N-terminus sequence (SSSHPIFHRGEFSV (c-NGF(1-14)). Far-UV CD spectra and a computational study show that this peptide has a rigid conformation and left-handed chirality typical of polyproline II that favors its interaction with the D5 domain of the NGF receptor TrkA. c-NGF(1-14) is able to bind Cu2+ with good affinity; the resulting complexes have been characterized by potentiometric and spectroscopic measurements. Experiments on PC12 cells show that c-NGF(1-14) acts as an ionophore, influencing the degree and the localization of both the membrane transporter (Ctr1) and the copper intracellular transporter (CCS). c-NGF(1-14) induces PC12 differentiation, mimics the protein in TrkA phosphorylation, and activates the kinase cascade, inducing Erk1/2 phosphorylation. c-NGF(1-14) biological activities are enhanced when the peptide interacts with Cu2+ even with the submicromolar quantities present in the culture media as demonstrated by ICP-OES measurements. Finally, c-NGF(1-14) and Cu2+ concur to activate the cAMP response element-binding protein CREB that, in turn, induces the brain-derived neurotrophic factor (BDNF) and the vascular endothelial growth factor (VEGF) release.

Keywords:  NGF mimics; PC12 cells; copper homeostasis; copper signaling; molecular simulations; trophic factors

DOI:  https://doi.org/10.1021/acschemneuro.3c00716
Clin Cancer Res. 2024 Apr 09.

Preclinical efficacy of a PSMA-targeted actinium-225 conjugate (225Ac-macropa-pelgifatamab) - a targeted alpha therapy for prostate cancer.

Christoph A Schatz, Sabine Zitzmann-Kolbe, Ingrid Moen, Monika Klotz, Shankari Nair, Stefan Stargard, Roger M Bjerke, Katrine Wickstrøm Biseth, Yuan Zeng Feng, Bård Indrevoll, Véronique Cruciani, Jenny Karlsson, Bernard Haendler, Carsten H Nielsen, Maria Z Alfsen, Stefanie Hammer, Hartwig Hennekes, Alan Cuthbertson, Urs B Hagemann, Aasmund Larsen.

PURPOSE: Initially, prostate cancer responds to hormone therapy but eventually resistance develops. Beta emitter-based PSMA (prostate-specific membrane antigen)-targeted radionuclide therapy is approved for the treatment of metastatic castration-resistant prostate cancer. Here we introduce a targeted alpha therapy (TAT) consisting of the PSMA antibody pelgifatamab covalently linked to a macropa chelator and labeled with actinium-225 and compare its efficacy and tolerability with other TATs.EXPERIMENTAL DESIGN: The in vitro characteristics and in vivo biodistribution, antitumor efficacy, and tolerability of 225Ac-macropa-pelgifatamab (225Ac-pelgi) and other TATs were investigated in cell line- and patient-derived prostate cancer xenograft models. The antitumor efficacy of 225Ac-pelgi was also investigated in combination with the androgen receptor inhibitor darolutamide.
RESULTS: Actinium-225-labeling of 225Ac-pelgi was efficient already at room temperature. Potent in vitro cytotoxicity was seen in PSMA-expressing (LNCaP, MDA-PCa-2b, and C4-2) but not in PSMA-negative (PC-3 and DU-145) cell lines. High tumor accumulation was seen for both 225Ac-pelgi and 225Ac-DOTA-pelgi in the MDA-PCa-2b xenograft model. In the C4-2 xenograft model, 225Ac-pelgi showed enhanced antitumor efficacy with a T/Cvolume (treatment/control) ratio of 0.10 compared with 225Ac-DOTA-pelgi, 225Ac-DOTA-J591, and 227Th-HOPO-pelgifatamab (227Th-pelgi) (all at 300 kBq/kg) with T/Cvolume ratios of 0.37, 0.39, and 0.33, respectively. 225Ac-pelgi was less myelosuppressive than 227Th-pelgi. 225Ac-pelgi showed dose-dependent treatment efficacy in the patient-derived KuCaP-1 model and strong combination potential with darolutamide in both cell line- (22Rv1) and patient-derived (ST1273) xenograft models.
CONCLUSIONS: These results provide a strong rationale to investigate 225Ac-pelgi in patients with prostate cancer. A clinical phase 1 study has been initiated (NCT06052306).

DOI: https://doi.org/10.1158/1078-0432.CCR-23-3746
Mol Oncol. 2024 Apr 10.

TAS3681, an androgen receptor antagonist, prevents drug resistance driven by aberrant androgen receptor signaling in prostate cancer.

Shohei Yoshida, Daisuke Kajiwara, Masanao Seki, Manabu Tayama, Yuki Tanaka, Hiroya Mizutani, Ryoto Fujita, Keisuke Yamamura, Shigeo Okajima, Masanori Asai, Kazuhisa Minamiguchi.

  Second-generation androgen receptor (AR) signaling inhibitors (ARSIs), such as abiraterone and enzalutamide, prolong the life of patients with castration-resistant prostate cancer (CRPC). However, patients receiving ARSIs ultimately develop resistance through various complex mechanisms, including AR mutations, constitutively active AR-splice variants (AR-Vs), and AR overexpression. Here, we characterized a novel AR pure antagonist, TAS3681, which inhibits AR transcriptional activity and downregulates AR-full length (AR-FL) and AR-Vs. TAS3681 reduced the protein levels of AR-FL and AR-Vs including AR-V7 in enzalutamide-resistant cells (SAS MDV No. 3-14), in vitro and in vivo, showing strong antitumor efficacy in an AR-V7-positive xenograft model. In AR-overexpressing VCaP (prostate cancer) cells, conversely to enzalutamide, TAS3681 effectively suppressed cell proliferation and downregulated AR expression. Importantly, TAS3681 blocked the transcriptional activity of various mutant ARs, including mutations F877L/T878A and H875Y/T878A, which confer resistance to enzalutamide, and V716M and H875Y mutations, which confer resistance to darolutamide. Our results demonstrate that TAS3681 suppresses the reactivation of AR signaling, which causes resistance to ARSIs, via a newly identified mechanism of action. Therefore, TAS3681 could be a new therapeutic option for CRPC treatment.

Keywords:  TAS3681; androgen receptor; antagonist; prostate cancer; tumor resistance

DOI:  https://doi.org/10.1002/1878-0261.13641
Nat Commun. 2024 Apr 12. 15(1): 3188

A modular and synthetic biosynthesis platform for de novo production of diverse halogenated tryptophan-derived molecules.

Kevin B Reed, Sierra M Brooks, Jordan Wells, Kristin J Blake, Minye Zhao, Kira Placido, Simon d'Oelsnitz, Adit Trivedi, Shruti Gadhiyar, Hal S Alper.

Halogen-containing molecules are ubiquitous in modern society and present unique chemical possibilities. As a whole, de novo fermentation and synthetic pathway construction for these molecules remain relatively underexplored and could unlock molecules with exciting new applications in industries ranging from textiles to agrochemicals to pharmaceuticals. Here, we report a mix-and-match co-culture platform to de novo generate a large array of halogenated tryptophan derivatives in Escherichia coli from glucose. First, we engineer E. coli to produce between 300 and 700 mg/L of six different halogenated tryptophan precursors. Second, we harness the native promiscuity of multiple downstream enzymes to access unexplored regions of metabolism. Finally, through modular co-culture fermentations, we demonstrate a plug-and-play bioproduction platform, culminating in the generation of 26 distinct halogenated molecules produced de novo including precursors to prodrugs 4-chloro- and 4-bromo-kynurenine and new-to-nature halogenated beta carbolines.

DOI: https://doi.org/10.1038/s41467-024-47387-1
Adv Pharm Bull. 2024 Mar;14(1): 11-33

Recent Progress in the Oral Delivery of Therapeutic Peptides and Proteins: Overview of Pharmaceutical Strategies to Overcome Absorption Hurdles.

Sonal Mehrotra, Pavan Kalyan Bg, Pawan Ganesh Nayak, Alex Joseph, Jyothsna Manikkath.

  Purpose: Proteins and peptides have secured a place as excellent therapeutic moieties on account of their high selectivity and efficacy. However due to oral absorption limitations, current formulations are mostly delivered parenterally. Oral delivery of peptides and proteins (PPs) can be considered the need of the hour due to the immense benefits of this route. This review aims to critically examine and summarize the innovations and mechanisms involved in oral delivery of peptide and protein drugs.Methods: Comprehensive literature search was undertaken, spanning the early development to the current state of the art, using online search tools (PubMed, Google Scholar, ScienceDirect and Scopus).
Results: Research in oral delivery of proteins and peptides has a rich history and the development of biologics has encouraged additional research effort in recent decades. Enzyme hydrolysis and inadequate permeation into intestinal mucosa are the major causes that result in limited oral absorption of biologics. Pharmaceutical and technological strategies including use of absorption enhancers, enzyme inhibition, chemical modification (PEGylation, pro-drug approach, peptidomimetics, glycosylation), particulate delivery (polymeric nanoparticles, liposomes, micelles, microspheres), site-specific delivery in the gastrointestinal tract (GIT), membrane transporters, novel approaches (self-nanoemulsifying drug delivery systems, Eligen technology, Peptelligence, self-assembling bubble carrier approach, luminal unfolding microneedle injector, microneedles) and lymphatic targeting, are discussed. Limitations of these strategies and possible innovations for improving oral bioavailability of protein and peptide drugs are discussed.
Conclusion: This review underlines the application of oral route for peptide and protein delivery, which can direct the formulation scientist for better exploitation of this route.

Keywords:  Absorption; Biologics; Nanoparticles; Oral delivery; Peptides; Permeation enhancement; Proteins

DOI:  https://doi.org/10.34172/apb.2024.009
Cancers (Basel). 2024 Mar 23. pii: 1262. [Epub ahead of print]16(7):

Design and Preclinical Evaluation of a Novel Prostate-Specific Membrane Antigen Radioligand Modified with a Transthyretin Binder.

Christian Vaccarin, Ana Katrina Mapanao, Luisa M Deberle, Anna E Becker, Francesca Borgna, Giovanni Marzaro, Roger Schibli, Cristina Müller.

  Transthyretin binders have previously been used to improve the pharmacokinetic properties of small-molecule drug conjugates and could, thus, be utilized for radiopharmaceuticals as an alternative to the widely explored "albumin binder concept". In this study, a novel PSMA ligand modified with a transthyretin-binding entity (TB-01) was synthesized and labeled with lutetium-177 to obtain [177Lu]Lu-PSMA-TB-01. A high and specific uptake of [177Lu]Lu-PSMA-TB-01 was found in PSMA-positive PC-3 PIP cells (69 ± 3% after 4 h incubation), while uptake in PSMA-negative PC-3 flu cells was negligible (<1%). In vitro binding studies showed a 174-fold stronger affinity of [177Lu]Lu-PSMA-TB-01 to transthyretin than to human serum albumin. Biodistribution studies in PC-3 PIP/flu tumor-bearing mice confirmed the enhanced blood retention of [177Lu]Lu-PSMA-TB-01 (16 ± 1% IA/g at 1 h p.i.), which translated to a high tumor uptake (69 ± 13% IA/g at 4 h p.i.) with only slow wash-out over time (31 ± 8% IA/g at 96 h p.i.), while accumulation in the PC-3 flu tumor and non-targeted normal tissue was reasonably low. Further optimization of the radioligand design would be necessary to fine-tune the biodistribution and enable its use for therapeutic purposes. This study was the first of this kind and could motivate the use of the "transthyretin binder concept" for the development of future radiopharmaceuticals.

Keywords:  PC-3 PIP tumor cells; PSMA radioligand; lutetium-177; plasma protein binding; prostate cancer; transthyretin binder

DOI:  https://doi.org/10.3390/cancers16071262
Exp Cell Res. 2024 Apr 07. pii: S0014-4827(24)00124-1. [Epub ahead of print]438(1): 114033

Development and in-depth characterization of BRAFi-resistant melanoma cell lines in vitro and in vivo.

Aishwarya Saraswat, Ketan Patel.

  Regardless of the clinical response and improved patient survival observed following treatment with BRAFi like Vemurafenib (Vem), rapid development of resistance still remains as a major obstacle in melanoma therapy. In this context, we developed and characterized two acquired Vem-resistant melanoma cell lines, A375V and SK-MEL-28V, and an intrinsically Vem-resistant cell line, RPMI-7951. Altered morphology and growth rate of the resistant cell lines displayed spindle-shaped cells with filopodia formation and enhanced proliferation rate as compared to parental cells. Further in vitro characterization in 2D models confirmed the emergence of a resistant phenotype in melanoma cells. To mimic the in vivo tumor microenvironment, spheroids were developed for both parental and resistant cell lines to recognize materialization of invadopodia structures demonstrating elevated invasiveness and proliferation of resistant cells-based spheroids, especially A375V. Importantly, we validated A375V cell line in vivo to prove its tumorigenicity and drug resistance in tumor xenograft model. Taken together, our established clinically relevant Vem-resistant tumor model could be beneficial to elucidate drug resistance mechanisms, screen and identify novel anticancer therapies to overcome BRAFi resistance in melanoma.

Keywords:  3D spheroids; BRAF inhibitor; Drug resistance; Melanoma; Melanoma xenograft model; Resistance characterization; Vemurafenib

DOI:  https://doi.org/10.1016/j.yexcr.2024.114033
Brief Bioinform. 2024 Mar 27. pii: bbae134. [Epub ahead of print]25(3):

Correction to: Introducing π-HelixNovo for practical large-scale de novo peptide sequencing.

DOI: https://doi.org/10.1093/bib/bbae134
Bioorg Med Chem. 2024 Apr 03. pii: S0968-0896(24)00125-1. [Epub ahead of print]104 117711

Discovery of novel macrocyclic derivatives as potent and selective cyclin-dependent kinase 2 inhibitors.

Pengpeng Niu, Yanxin Tao, Qingyuan Meng, Yixing Huang, Shan Li, Ke Ding, Dawei Ma, Zu Ye, Mengyang Fan.

  Cyclin-dependent kinase 2 (CDK2) is a member of CDK family of kinases (CDKs) that regulate the cell cycle. Its inopportune or over-activation leads to uncontrolled cell cycle progression and drives numerous types of cancers, especially ovarian, uterine, gastric cancer, as well as those associated with amplified CCNE1 gene. However, developing selective lead compound as CDK2 inhibitors remains challenging owing to similarities in the ATP pockets among different CDKs. Herein, we described the optimization of compound 1, a novel macrocyclic inhibitor targeting CDK2/5/7/9, aiming to discover more selective and metabolically stable lead compound as CDK2 inhibitor. Molecular dynamic (MD) simulations were performed for compound 1 and 9 to gain insights into the improved selectivity against CDK5. Further optimization efforts led to compound 22, exhibiting excellent CDK2 inhibitory activity, good selectivity over other CDKs and potent cellular effects. Based on these characterizations, we propose that compound 22 holds great promise as a potential lead candidate for drug development.

Keywords:  CCNE1 amplification; Cyclin-dependent kinase 2; Macrocycle; Molecular dynamic simulations; Small molecule inhibitor

DOI:  https://doi.org/10.1016/j.bmc.2024.117711