Pharmacological Inhibition of LIM Kinase Stabilizes Microtubules and Inhibits Neoplastic Growth (original) (raw)

Microtubules and actin filaments: dynamic targets for cancer chemotherapy

Current Opinion in Cell Biology, 1998

Microtubules and actin filaments play important roles in mitosis, cell signaling, and motility. Thus these cytoskeletal filaments are the targets of a growing number of anti-cancer drugs. In this review we summarize the current understanding of the mechanisms of these drugs in relation to microtubule and actin filament polymerization and dynamics. In addition, we outline how, by targeting microtubules, drugs inhibit cell proliferation by blocking mitosis at the mitotic checkpoint and inducing apoptosis. The I~-tubulin isotype specificities of new anticancer drugs and the antitumor potential of agents that act on the actin cytoskeleton are also discussed.

LIMK1/TPPP1/HDAC6 Is a Dual Actin and Microtubule Regulatory Complex That Promotes Drug Resistance

In this study, we identified a novel protein complex consisting of LIM-Kinase 1 (LIMK1), Histone deacetylase 6 (HDAC6) and Tubulin Polymerization Promoting Protein 1 (TPPP1). Under basal conditions, assembly of the LIMK1/TPPP1/HDAC6 complex results in both inhibition of HDAC6 activity and LIMK1 activation. This leads to increased microtubule (MT) acetylation, a MT stabilizing modification, and actin filament (F-actin) destabilization. In response to activation of the Rhokinase (ROCK) signaling pathway, downstream phosphorylation of LIMK1 and TPPP1 leads to the dissociation of the LIMK1/TPPP1/HDAC6 complex. In turn, HDAC6 and LIMK1 activities are increased, which results in MT destabilization and F-actin stabilization. Finally, we reveal that increasing tubulin acetylation reduces the efficacy of chemotherapeutic drugs, suggesting that strategies to reduce acetyl-tubulin levels may be a viable option in treating drug-resistant tumors.

LIM Kinase Inhibitor Pyr1 Reduces the Growth and Metastatic Load of Breast Cancers

Cancer Research, 2016

LIM kinases (LIMK) are emerging targets for cancer therapy, and they function as network hubs to coordinate actin and microtubule dynamics. When LIMKs are inhibited, actin microfilaments are disorganized and microtubules are stabilized. Owing to their stabilizing effect on microtubules, LIMK inhibitors may provide a therapeutic strategy to treat taxane-resistant cancers. In this study, we investigated the effect of LIMK inhibition on breast tumor development and on paclitaxel-resistant tumors, using a novel selective LIMK inhibitor termed Pyr1. Treatment of breast cancer cells, including paclitaxel-resistant cells, blocked their invasion and proliferation in vitro and their growth in vivo in tumor xenograft assays. The tumor-invasive properties of Pyr1 were investigated in vivo by intravital microscopy of tumor xenografts. A striking change of cell morphology was observed with a rounded phenotype arising in a subpopulation of cells, while other cells remained elongated. Notably, although Pyr1 decreased the motility of elongated cells, it increased the motility of rounded cells in the tumor. Pyr1 administration prevented the growth of metastasis but not their spread. Overall, our results provided a preclinical proof of concept concerning how a small-molecule inhibitor of LIMK may offer a strategy to treat taxane-resistant breast tumors and metastases. Cancer Res; 76(12); 3541-52. Ó2016 AACR.

LIM kinases: cofilin and beyond

Oncotarget, 2017

LIM kinases are common downstream effectors of several signalization pathways and function as a signaling node that controls cytoskeleton dynamics through the phosphorylation of the cofilin family proteins. These last 10 years, several reports indicate that the functions of LIM kinases are more extended than initially described and, specifically, that LIM kinases also control microtubule dynamics, independently of their regulation of actin microfilament. In this review we analyze the data supporting these conclusions and the possible mechanisms that could be involved in the control of microtubules by LIM kinases. The demonstration that LIM kinases also control microtubule dynamics has pointed to new therapeutic opportunities. Consistently, several new LIM kinase inhibitors have been recently developed. We provide a comprehensive comparison of these inhibitors, of their chemical structure, their specificity, their cellular effects as well as their effects in animal models of various diseases including cancer.