Toward the Validation of Maternal Embryonic Leucine Zipper Kinase: Discovery, Optimization of Highly Potent and Selective Inhibitors, and Preliminary Biology Insight

Touré, B. Barry; Giraldes, John; Smith, Troy; Sprague, Elizabeth R.; Wang, Yaping; Mathieu, Simon; Chen, Zhuoliang; Mishina, Yuji; Feng, Yun; Yan‐Neale, Yan; Shakya, Subarna; Chen, Dongshu; Meyer, Matthew J.; Puleo, D.E.; Brazell, J. Tres; Straub, Christopher; Sage, David R.; Wright, Kirk; Yuan, Yanqiu; Chen, Xin; Duca, José S.; Kim, Sean; Tian, Li; Martin, Éric; Hurov, Kristen E.; Shao, Wenlin

doi:10.1021/acs.jmedchem.6b00052

Cited by 44 publications

(45 citation statements)

References 24 publications

(64 reference statements)

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“…OTSSP167 treatment significantly inhibited melanoma cell line proliferation (Figure 2A) and colony formation in a soft-agar assay (Figure 2B–C and Figure S2). To confirm that the growth inhibition was due to MELK kinase inhibition and not an off-target effect, we also treated cells with a second MELK inhibitor, MELK-8a (Toure et al, 2016). Consistent with our results with OTSSP167, MELK-8a inhibited melanoma cell growth in both the proliferation (Figure S3A) and soft-agar (Figure S3B–C) assays.…”

Section: Resultsmentioning

confidence: 99%

MELK Promotes Melanoma Growth by Stimulating the NF-κB Pathway

et al. 2017

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SUMMARY Melanoma accounts for over 80% of skin cancer-related deaths and current therapies provide only short-term benefit to patients. Here, we show in melanoma cells that maternal embryonic leucine zipper kinase (MELK) is transcriptionally upregulated by the MAP kinase pathway via transcription factor E2F1. MELK knockdown or pharmacological inhibition blocked melanoma growth and enhanced the effectiveness of BRAFV600E inhibitor against melanoma cells. To identify mediators of MELK function, we performed stable isotope labeling with amino acids in cell culture (SILAC) and identified 469 proteins that had downregulated phosphorylation after MELK inhibition. Remarkably, 139 of these proteins were previously reported as substrates of BRAF or MEK, demonstrating that MELK is an important downstream mediator of the MAPK pathway. Furthermore, we show that MELK promotes melanoma growth by activating NF-κB pathway activity via Sequestosome 1 (SQSTM1/p62). Collectively, these results underpin an important role for MELK in melanoma growth, downstream of the MAPK pathway.

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Section: Resultsmentioning

confidence: 99%

MELK Promotes Melanoma Growth by Stimulating the NF-κB Pathway

et al. 2017

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“…In particular, MELK has been identified as a key driver of basal-type breast cancer, suggesting a novel therapeutic approach to treat this disease (Wang et al, 2014). In response to the widespread reports that MELK is a cancer dependency, several companies have developed small molecule inhibitors of MELK that block the activity of the kinase in vitro and that inhibit cancer cell proliferation at micromolar or nanomolar concentrations (Beke et al, 2015; Touré et al, 2016; Johnson et al, 2015a, 2015b; Chung et al, 2012). Additionally, four clinical trials have been launched to test the MELK inhibitor OTS167 in human cancers (NCT01910545, NCT02768519, NCT02795520, and NCT02926690).…”

Section: Introductionmentioning

confidence: 99%

CRISPR/Cas9 mutagenesis invalidates a putative cancer dependency targeted in on-going clinical trials

Lin

Giuliano

Sayles

et al. 2017

eLife

118

115

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The Maternal Embryonic Leucine Zipper Kinase (MELK) has been reported to be a genetic dependency in several cancer types. MELK RNAi and small-molecule inhibitors of MELK block the proliferation of various cancer cell lines, and MELK knockdown has been described as particularly effective against the highly-aggressive basal/triple-negative subtype of breast cancer. Based on these preclinical results, the MELK inhibitor OTS167 is currently being tested as a novel chemotherapy agent in several clinical trials. Here, we report that mutagenizing MELK with CRISPR/Cas9 has no effect on the fitness of basal breast cancer cell lines or cell lines from six other cancer types. Cells that harbor null mutations in MELK exhibit wild-type doubling times, cytokinesis, and anchorage-independent growth. Furthermore, MELK-knockout lines remain sensitive to OTS167, suggesting that this drug blocks cell division through an off-target mechanism. In total, our results undermine the rationale for a series of current clinical trials and provide an experimental approach for the use of CRISPR/Cas9 in preclinical target validation that can be broadly applied.DOI: http://dx.doi.org/10.7554/eLife.24179.001

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“…The maternal embryonic leucine zipper kinase (MELK) has been reported as a particularly effective target for the treatment of TNBC, in which MELK is overexpressed . Consequently, multiple drugs that inhibit MELK activity have been synthesized as a means for therapy . Although the MELK inhibitor OTS167 has been studied in several clinical trials (NCT01910545, NCT02768519, NCT02795520, and NCT02926690), Lin et al discovered that for TNBC, the mutagenesis of MELK with Cas9 did not affect the growth of TNBC cell lines .…”

Section: Crispr Technology For Breast Cancer Modelingmentioning

confidence: 99%

CRISPR Technology for Breast Cancer: Diagnostics, Modeling, and Therapy

Mintz

Gao

et al. 2018

Adv. Biosys.

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Molecularly, breast cancer represents a highly heterogenous family of neoplastic disorders, with substantial interpatient variations regarding genetic mutations, cell composition, transcriptional profiles, and treatment response. Consequently, there is an increasing demand for alternative diagnostic approaches aimed at the molecular annotation of the disease on a patient‐by‐patient basis and the design of more personalized treatments. The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated (Cas) technology enables the development of such novel approaches. For instance, in diagnostics, the use of the RNA‐specific C2c2 system allows ultrasensitive nucleic acid detection and could be used to characterize the mutational repertoire and transcriptional breast cancer signatures. In disease modeling, CRISPR/Cas9 technology can be applied to selectively engineer oncogenes and tumor‐suppressor genes involved in disease pathogenesis. In treatment, CRISPR/Cas9 can be used to develop gene‐therapy, while its catalytically‐dead variant (dCas9) can be applied to reprogram the epigenetic landscape of malignant cells. As immunotherapy becomes increasingly prominent in cancer treatment, CRISPR/Cas9 can engineer the immune cells to redirect them against cancer cells and potentiate antitumor immune responses. In this review, CRISPR strategies for the advancement of breast cancer diagnostics, modeling, and treatment are highlighted, culminating in a perspective on developing a precision medicine‐based approach against breast cancer.

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Toward the Validation of Maternal Embryonic Leucine Zipper Kinase: Discovery, Optimization of Highly Potent and Selective Inhibitors, and Preliminary Biology Insight

Cited by 44 publications

References 24 publications

MELK Promotes Melanoma Growth by Stimulating the NF-κB Pathway

MELK Promotes Melanoma Growth by Stimulating the NF-κB Pathway

CRISPR/Cas9 mutagenesis invalidates a putative cancer dependency targeted in on-going clinical trials

CRISPR Technology for Breast Cancer: Diagnostics, Modeling, and Therapy

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