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A tubulin binding peptide targets glioma cells disrupting their microtubules, blocking migration, and inducing apoptosis.

ABSTRACT: Despite aggressive treatment regimes, glioma remains a largely fatal disease. Current treatment limitations are attributed to the precarious locations within the brain where such tumors grow, their highly infiltrative nature precluding complete resection and lack of specificity among agents capable of attenuating their growth. Here, we show that in vitro, glioma cells of diverse origins internalize a peptide encompassing a tubulin-binding site (TBS) on the neurofilament light protein. The internalized peptide disrupts the microtubule network, inhibits migration and proliferation, and leads to apoptosis. Using an intracerebral transplant model, we show that most, if not all, of these responses to peptide exposure also occur in vivo. Notably, a single intratumor injection significantly attenuates tumor growth, while neither peptide uptake nor downstream consequences are observed elsewhere in the host nervous system. Such preferential uptake suggests that the peptide may have potential as a primary or supplementary glioblastoma treatment modality by exploiting its autonomous microtubule-disrupting activity or engaging its capacity to selectively target glioma cells with other cell-disrupting cargos.

SUBMITTER: Berges R

PROVIDER: S-EPMC3392973 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Tubulin/microtubules as novel clozapine targets.

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| S-EPMC8919115 | biostudies-literature

Mechanism of how augmin directly targets the ?-tubulin ring complex to microtubules.

Project description:Microtubules (MTs) must be generated from precise locations to form the structural frameworks required for cell shape and function. MTs are nucleated by the ?-tubulin ring complex (?-TuRC), but it remains unclear how ?-TuRC gets to the right location. Augmin has been suggested to be a ?-TuRC targeting factor and is required for MT nucleation from preexisting MTs. To determine augmin's architecture and function, we purified Xenopus laevis augmin from insect cells. We demonstrate that augmin is sufficient to target ?-TuRC to MTs by in vitro reconstitution. Augmin is composed of two functional parts. One module (tetramer-II) is necessary for MT binding, whereas the other (tetramer-III) interacts with ?-TuRC. Negative-stain electron microscopy reveals that both tetramers fit into the Y-shape of augmin, and MT branching assays reveal that both are necessary for MT nucleation. The finding that augmin can directly bridge MTs with ?-TuRC via these two tetramers adds to our mechanistic understanding of how MTs can be nucleated from preexisting MTs.

| S-EPMC6028527 | biostudies-literature

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Dinitroanilines bind alpha-tubulin to disrupt microtubules.

Project description:Protozoan parasites are remarkably sensitive to dinitroanilines such as oryzalin, which disrupt plant but not animal microtubules. To explore the basis of dinitroaniline action, we isolated 49 independent resistant Toxoplasma gondii lines after chemical mutagenesis. All 23 of the lines that we examined harbored single point mutations in alpha-tubulin. These point mutations were sufficient to confer resistance when transfected into wild-type parasites. Several mutations were in the M or N loops, which coordinate protofilament interactions in the microtubule, but most of the mutations were in the core of alpha-tubulin. Docking studies predict that oryzalin binds with an average affinity of 23 nM to a site located beneath the N loop of Toxoplasma alpha-tubulin. This binding site included residues that were mutated in several resistant lines. Moreover, parallel analysis of Bos taurus alpha-tubulin indicated that oryzalin did not interact with this site and had a significantly decreased, nonspecific affinity for vertebrate alpha-tubulin. We propose that the dinitroanilines act through a novel mechanism, by disrupting M-N loop contacts. These compounds also represent the first class of drugs that act on alpha-tubulin function.

| S-EPMC379290 | biostudies-literature

Resolving bundled microtubules using anti-tubulin nanobodies.

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| S-EPMC4918323 | biostudies-literature

Parthenolide Destabilizes Microtubules by Covalently Modifying Tubulin.

Project description:Detyrosination of the α-tubulin C-terminal tail is a post-translational modification (PTM) of microtubules that is key for many biological processes.1 Although detyrosination is the oldest known microtubule PTM,2-7 the carboxypeptidase responsible for this modification, VASH1/2-SVBP, was identified only 3 years ago,8,9 precluding genetic approaches to prevent detyrosination. Studies examining the cellular functions of detyrosination have therefore relied on a natural product, parthenolide, which is widely believed to block detyrosination of α-tubulin in cells, presumably by inhibiting the activity of the relevant carboxypeptidase(s).10 Parthenolide is a sesquiterpene lactone that forms covalent linkages predominantly with exposed thiol groups; e.g., on cysteine residues.11-13 Using mass spectrometry, we show that parthenolide forms adducts on both cysteine and histidine residues on tubulin itself, in vitro and in cells. Parthenolide causes tubulin protein aggregation and prevents the formation of microtubules. In contrast to epoY, an epoxide inhibitor of VASH1/2-SVBP,9 parthenolide does not block VASH1-SVBP activity in vitro. Lastly, we show that epoY is an efficacious inhibitor of microtubule detyrosination in cells, providing an alternative chemical means to block detyrosination. Collectively, our work supports the notion that parthenolide is a promiscuous inhibitor of many cellular processes and suggests that its ability to block detyrosination may be an indirect consequence of reducing the polymerization-competent pool of tubulin in cells.

| S-EPMC7931505 | biostudies-literature

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| S-EPMC4084924 | biostudies-literature

A Comprehensive Study on the Electrostatic Properties of Tubulin-Tubulin Complexes in Microtubules.

Project description:Microtubules are key players in several stages of the cell cycle and are also involved in the transportation of cellular organelles. Microtubules are polymerized by α/β tubulin dimers with a highly dynamic feature, especially at the plus ends of the microtubules. Therefore, understanding the interactions among tubulins is crucial for characterizing microtubule dynamics. Studying microtubule dynamics can help researchers make advances in the treatment of neurodegenerative diseases and cancer. In this study, we utilize a series of computational approaches to study the electrostatic interactions at the binding interfaces of tubulin monomers. Our study revealed that among all the four types of tubulin-tubulin binding modes, the electrostatic attractive interactions in the α/β tubulin binding are the strongest while the interactions of α/α tubulin binding in the longitudinal direction are the weakest. Our calculations explained that due to the electrostatic interactions, the tubulins always preferred to form α/β tubulin dimers. The interactions between two protofilaments are the weakest. Thus, the protofilaments are easily separated from each other. Furthermore, the important residues involved in the salt bridges at the binding interfaces of the tubulins are identified, which illustrates the details of the interactions in the microtubule. This study elucidates some mechanistic details of microtubule dynamics and also identifies important residues at the binding interfaces as potential drug targets for the inhibition of cancer cells.

| S-EPMC9857020 | biostudies-literature

Tubulin dimers oligomerize before their incorporation into microtubules.

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| S-EPMC2584370 | biostudies-literature

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