Anti‐angiogenic effects of the tubulysin precursor pretubulysin and of simplified pretubulysin derivatives

Rath, Sebastian; Liebl, Johanna; Fürst, Robert; Ullrich, Angelika; Burkhart, JL; Kazmaier, Uli; Herrmann, Jennifer; Müller, Rolf; Günther, Michael; Schreiner, L; Wagner, Ernst; Am, Vollmar; Zahler, Stefan

doi:10.1111/j.1476-5381.2012.02037.x

Cited by 40 publications

(43 citation statements)

References 29 publications

(43 reference statements)

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“…According to the previous study of Rath et al , 20 6 days after tumor cell injection, 0.1 mg/kg pretubulysin in PBS was injected intravenously every second day. After 39 days, mice were killed and tumor growth and weight of 10 control- and 7 pretubulysin-treated mice was determined.…”

Section: Methodsmentioning

confidence: 99%

Pretubulysin: a new option for the treatment of metastatic cancer

Braig¹,

Wiedmann²,

Liebl³

et al. 2014

Cell Death Dis

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Tubulin-binding agents such as taxol, vincristine or vinblastine are well-established drugs in clinical treatment of metastatic cancer. However, because of their highly complex chemical structures, the synthesis and hence the supply issues are still quite challenging. Here we set on stage pretubulysin, a chemically accessible precursor of tubulysin that was identified as a potent microtubule-binding agent produced by myxobacteria. Although much simpler in chemical structure, pretubulysin abrogates proliferation and long-term survival as well as anchorage-independent growth, and also induces anoikis and apoptosis in invasive tumor cells equally potent to tubulysin. Moreover, pretubulysin posseses in vivo efficacy shown in a chicken chorioallantoic membrane (CAM) model with T24 bladder tumor cells, in a mouse xenograft model using MDA-MB-231 mammary cancer cells and finally in a model of lung metastasis induced by 4T1 mouse breast cancer cells. Pretubulysin induces cell death via the intrinsic apoptosis pathway by abrogating the expression of pivotal antiapoptotic proteins, namely Mcl-1 and Bcl-xL, and shows distinct chemosensitizing properties in combination with TRAIL in two- and three-dimensional cell culture models. Unraveling the underlying signaling pathways provides novel information: pretubulysin induces proteasomal degradation of Mcl-1 by activation of mitogen-activated protein kinase (especially JNK (c-Jun N-terminal kinase)) and phosphorylation of Mcl-1, which is then targeted by the SCFFbw7 E3 ubiquitin ligase complex for ubiquitination and degradation. In sum, we designate the microtubule-destabilizing compound pretubulysin as a highly promising novel agent for mono treatment and combinatory treatment of invasive cancer.

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Section: Methodsmentioning

confidence: 99%

Pretubulysin: a new option for the treatment of metastatic cancer

Braig¹,

Wiedmann²,

Liebl³

et al. 2014

Cell Death Dis

Self Cite

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“…Scratch assays on confluent cell monolayers were conducted as described previously (17). Details are described in Supplementary Methods.…”

Section: Scratch Assaymentioning

confidence: 99%

Indirubin Derivative 6BIO Suppresses Metastasis

et al. 2013

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While metastasis is the chief cause of cancer mortality, there nonetheless remains a lack of antimetastatic therapies that are clinically available. In this study, we present the indirubin derivative 6-bromo-indirubin-3 0 -oxime (6BIO) as a promising antimetastatic agent. 6BIO strongly reduced formation of lung metastasis in the well-established 4T1 mouse model of aggressive breast cancer. Several major hallmarks of the metastatic process were affected by subtoxic concentrations of 6BIO, which inhibited adhesion, migration, and invasion of a variety of metastatic cell types in vitro. Mechanistic analyses focused on known targets of 6BIO, which were silenced by this compound. Unexpectedly, RNAi-mediated silencing of glycogen synthase kinase 3b (GSK3b) and phosphoinositide-dependent protein kinase 1 (PDK1), both modulators of cellular metastasis targeted by 6BIO, were not found to affect invasive migration in this study. Instead, the Jak/STAT3 signaling pathway appeared to play a major role through modulation of its downstream migration regulators Cterminal tensin-like protein and matrix metalloproteinase 2. However, PDK1 and GSK3b contributed to the overall response to 6BIO, as silencing of all three pathways resulted in almost complete inhibition of migration, phenocopying the 6BIO response. Taken together, our findings illustrate the antimetastatic activity of 6BIO on the basis of its ability to simultaneously inhibit several kinase cascades involved in metastasis of cancer cells, supporting the concept of "polypharmacology" in developing drugs to attack metastasis, the most deadly aspect of cancer. Cancer Res; 73(19); 6004-12. Ó2013 AACR.

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“…4b). Interestingly, the same phenotype has been reported for pretubulysin previously [38][39][40] but so far the direct binding to tubulin could not be directly confirmed. Here we demonstrate by co-staining with the tubulin directed antibody as well as the fluorescent probe that pretubulysin derivative 4 binds to monomeric tubulin which appear as little spots in the image ( Fig.…”

Section: Fluorescence Imagingmentioning

confidence: 59%

Pretubulysin derived probes as novel tools for monitoring the microtubule network via activity-based protein profiling and fluorescence microscopy

et al. 2012

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Microtubules (mt) are highly dynamic polymers composed of alpha-and beta-tubulin monomers that are present in all dividing and non-dividing cells. A broad variety of natural products exists that are known to interfere with the microtubule network, by either stabilizing or de-stabilizing these rope-like polymers. Among those tubulysins represent a new and potent class of cytostatic tetrapeptides originating from myxobacteria. Early studies suggested that tubulysins interact with the eukaryotic cytoskeleton by inhibition of tubulin polymerization with EC 50 values in the picomolar range. Recently, pretubulysins have been described to retain the high tubulindegradation activity of their more complex tubulysin relatives and represent an easier synthetic target with an efficient synthesis already in place. Although tubulin has been suggested as the dedicated target of tubulysin a comprehensive molecular target analysis of pretubulysin in the context of the whole proteome has not been carried out so far. Here we utilize synthetic chemistry to develop two pretubulysin photoaffinity probes which were applied in cellular activity-based protein profiling and imaging studies in order to unravel and visualize dedicated targets. Our results clearly show a remarkable selectivity of pretubulysin for beta-tubulin which we independently confirmed by a mass-spectrometry based proteomic profiling platform as well as by tubulin antibody based co-staining on intact cells.

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Anti‐angiogenic effects of the tubulysin precursor pretubulysin and of simplified pretubulysin derivatives

Cited by 40 publications

References 29 publications

Pretubulysin: a new option for the treatment of metastatic cancer

Pretubulysin: a new option for the treatment of metastatic cancer

Indirubin Derivative 6BIO Suppresses Metastasis

Pretubulysin derived probes as novel tools for monitoring the microtubule network via activity-based protein profiling and fluorescence microscopy

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