ACK1 tyrosine kinase: targeted inhibition to block cancer cell proliferation

ZNF692 promotes osteosarcoma cell proliferation, migration, and invasion through TNK2-mediated activation of the MEK/ERK pathway

BACKGROUND

Osteosarcoma is a diverse and aggressive bone tumor. Driver genes regulating osteosarcoma initiation and progression remains incompletely defined. Zinc finger protein 692 (ZNF692), a kind of Krüppel C2H2 zinc finger transcription factor, exhibited abnormal expression in different types of malignancies and showed a correlation with the clinical prognosis of patients as well as the aggressive characteristics of cancer cells. Nevertheless, its specific role in osteosarcoma is still not well understood.

METHODS

We investigated the dysregulation and clinical significance of ZNF692 in osteosarcoma through bioinformatic method and experimental validation. A range of in vitro assays, including CCK-8, colony formation, EdU incorporation, wound healing, and transwell invasion tests, were conducted to assess the impact of ZNF692 on cell proliferation, migration, and invasion in osteosarcoma. A xenograft mouse model was established to evaluate the effect of ZNF692 on tumor growth in vivo. Western blot assay was used to measure the protein levels of MEK1/2, P-MEK1/2, ERK1/2, and P-ERK1/2 in cells that had been genetically modified to either reduce or increase the expression of ZNF692. The relationship between ZNF692 and tyrosine kinase non-receptor 2 (TNK2) were validated by qRT-PCR, chromatin immunoprecipitation and luciferase reporter assays.

RESULTS

Expression of ZNF692 was increased in both human osteosarcoma tissues and cell lines. Furthermore, the expression of ZNF692 served as an independent predictive biomarker in osteosarcoma. The results of the survival analysis indicated that increased expression of ZNF692 was associated with worse outcome. Downregulation of ZNF692 inhibits the proliferation, migration, and invasion of osteosarcoma cells, whereas upregulation of ZNF692 has the opposite impact. Western blot assay indicates that reducing ZNF692 decreases phosphorylation of MEK1/2 and ERK1/2, whereas increasing ZNF692 expression enhances their phosphorylation. U0126, a potent inhibitor specifically targeting the MEK/ERK signaling pathway, partially counteracts the impact of ZNF692 overexpression on the proliferation, migration, and invasion of osteosarcoma cells. In addition, ZNF692 specifically interacts with the promoter region of TNK2 and stimulates the transcription of TNK2 in osteosarcoma cells. Forcing the expression of TNK2 weakens the inhibitory impact of ZNF692 knockdown on P-MEK1/2 and P-ERK1/2. Similarly, partly inhibiting TNK2 counteracts the enhancing impact of ZNF692 overexpression on the phosphorylation of MEK1/2 and ERK1/2. Functional tests demonstrate that the suppressive effects of ZNF692 knockdown on cell proliferation, migration, and invasion are greatly reduced when TNK2 is overexpressed. In contrast, the reduction of TNK2 hinders the ability of ZNF692 overexpression to enhance cell proliferation, migration, and invasion.

CONCLUSION

ZNF692 promotes the proliferation, migration, and invasion of osteosarcoma cells via the TNK2-dependent stimulation of the MEK/ERK signaling pathway. The ZNF692-TNK2 axis might potentially function as a possible predictive biomarker and a promising target for novel therapeutics in osteosarcoma.

Design, Synthesis, and Biological Evaluation of Dual Inhibitors of EGFRL858R/T790M/ACK1 to Overcome Osimertinib Resistance in Nonsmall Cell Lung Cancers

Activation of the alternative pathways and abnormal signaling transduction are frequently observed in third-generation EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors)-resistant patients. Wherein, hyperphosphorylation of ACK1 contributes to EGFR-TKIs acquired resistance. Dual inhibition of EGFRL858R/T790M and ACK1 might improve therapeutic efficacy and overcome resistance in lung cancers treatment. Here, we identified a EGFRL858R/T790M/ACK1 dual-targeting compound 21a with aminoquinazoline scaffold, which showed excellent inhibitory activities against EGFRL858R/T790M (IC50 = 23 nM) and ACK1 (IC50 = 263 nM). The cocrystal and docking analysis showed that 21a occupied the ATP binding pockets of EGFRL858R/T790M and ACK1. Moreover, 21a showed potent antiproliferative activities against the H1975 cells, MCF-7 cells and osimertinib-resistant cells AZDR. Further, 21a showed significant antitumor effects and good safety in ADZR xenograft-bearing mice. Taken together, 21a was a potent dual inhibitor of EGFRL858R/T790M/ACK1, which is deserved as a potential lead for overcoming acquired resistance to osimertinib during the EGFR-targeted therapy.

Prostate cancer immunotherapy: Improving clinical outcomes with a multi-pronged approach

Cancer immunotherapy has gained traction in recent years owing to remarkable tumor clearance in some patients. Despite the notable success of immune checkpoint blockade (ICB) in multiple malignancies, engagement of the immune system for targeted prostate cancer (PCa) therapy is still in its infancy. Multiple factors contribute to limited response, including the heterogeneity of PCa, the cold tumor microenvironment, and a low number of neoantigens. Significant effort is being invested in improving immune-based PCa therapies. This review is a summary of the status of immunotherapy in treating PCa, with a discussion of multiple immune modalities, including vaccines, adoptively transferred T cells, and bispecific T cell engagers, some of which are undergoing clinical trials. In addition, this review also focuses on emerging mechanism-based small-molecule tyrosine kinase inhibitors with immune modulatory properties that, either as single agents or in combination with other immunotherapies, have the potential to improve clinical outcomes.

Off-target pharmacological activity at various kinases: Potential functional and pathological side effects

In drug discovery, during the lead optimization and candidate characterization stages, novel small molecules are frequently evaluated in a battery of in vitro pharmacology assays to identify potential unintended, off-target interactions with various receptors, transporters, ion channels, and enzymes, including kinases. Furthermore, these screening panels may also provide utility at later stages of development to provide a mechanistic understanding of unexpected safety findings. Here, we present a compendium of the most likely functional and pathological outcomes associated with interaction(s) to a panel of 95 kinases based on an extensive curation of the scientific literature. This panel of kinases was designed by AbbVie based on safety-related data extracted from the literature, as well as from over 20 years of institutional knowledge generated from discovery efforts. For each kinase, the scientific literature was reviewed using online databases and the most often reported functional and pathological effects were summarized. This work should serve as a practical guide for small molecule drug discovery scientists and clinical investigators to predict and/or interpret adverse effects related to pharmacological interactions with these kinases.

Paris saponins Ⅶ inhibits glycolysis of ovarian cancer via the RORC/ACK1 signaling pathway

Rhizoma Paridis is a traditional Chinese medicine commonly used for treatment of malignant tumors. Paris saponins Ⅶ (PSⅦ) is one of the components of Rhizoma Paridis, but the role of PSⅦ in glucose metabolism in ovarian cancer remains elucidated. A series of experiments in the current study demonstrated that PSⅦ inhibites glycolysis and promotes cell apoptosis in ovarian cancer cells. Expression levels of glycolysis-related proteins and apoptosis-related proteins were significantly altered by upon treatment with PSⅦ, as determined from western blot analyses. Mechanistically, PSⅦ exerted its anti-tumor effects by targeting the RORC/ACK1 signaling pathway. These findings indicate that PSⅦ inhibits glycolysis-induced cell proliferation and apoptosis through the RORC/ACK1 pathway, supporting its potential development as a candidate chemotherapeutic agent for ovarian cancer.

Identification of Activated Cdc42-Associated Kinase Inhibitors as Potential Anticancer Agents Using Pharmacoinformatic Approaches

BACKGROUND

Activated Cdc42-associated kinase (ACK1) is essential for numerous cellular functions, such as growth, proliferation, and migration. ACK1 signaling occurs through multiple receptor tyrosine kinases; therefore, its inhibition can provide effective antiproliferative effects against multiple human cancers. A number of ACK1-specific inhibitors were designed and discovered in the previous decade, but none have reached the clinic. Potent and selective ACK1 inhibitors are urgently needed.

METHODS

In the present investigation, the pharmacophore model (PM) was rationally built utilizing two distinct inhibitors coupled with ACK1 crystal structures. The generated PM was utilized to screen the drug-like database generated from the four chemical databases. The binding mode of pharmacophore-mapped compounds was predicted using a molecular docking (MD) study. The selected hit-protein complexes from MD were studied under all-atom molecular dynamics simulations (MDS) for 500 ns. The obtained trajectories were ranked using binding free energy calculations (ΔG kJ/mol) and Gibb's free energy landscape.

RESULTS

Our results indicate that the three hit compounds displayed higher binding affinity toward ACK1 when compared with the known multi-kinase inhibitor dasatinib. The inter-molecular interactions of Hit1 and Hit3 reveal that compounds form desirable hydrogen bond interactions with gatekeeper T205, hinge region A208, and DFG motif D270. As a result, we anticipate that the proposed scaffolds might help in the design of promising selective ACK1 inhibitors.

Improvement of ACK1-targeted therapy efficacy in lung adenocarcinoma using chloroquine or bafilomycin A1

BACKGROUND

Activated Cdc42-associated kinase 1 (ACK1) is a promising druggable target for cancer, but its inhibitors only showed moderate effects in clinical trials. The study aimed to investigate the underlying mechanisms and improve the antitumor efficacy of ACK1 inhibitors.

METHODS

RNA-seq was performed to determine the downstream pathways of ACK. Using Lasso Cox regression analysis, we built a risk signature with ACK1-related autophagy genes in the lung adenocarcinoma (LUAD) patients from The Cancer Genome Atlas (TCGA) project. The performance of the signature in predicting the tumor immune environment and response to immunotherapy and chemotherapy were assessed in LUAD. CCK8, mRFP-GFP-LC3 assay, western blot, colony formation, wound healing, and transwell migration assays were conducted to evaluate the effects of the ACK1 inhibitor on lung cancer cells. A subcutaneous NSCLC xenograft model was used for in vivo study.

RESULTS

RNA-seq revealed the regulatory role of ACK1 in autophagy. Furthermore, the risk signature separated LUAD patients into low- and high-risk groups with significantly different prognoses. The two groups displayed different tumor immune environments regarding 28 immune cell subsets. The low-risk groups showed high immune scores, high CTLA4 expression levels, high immunophenoscore, and low DNA mismatch repair capacity, suggesting a better response to immunotherapy. This signature also predicted sensitivity to commonly used chemotherapy and targeted drugs. In vitro, the ACK1 inhibitors (AIM-100 and Dasatinib) appeared to trigger adaptive autophagy-like response to protect lung cancer cells from apoptosis and activated the AMPK/mTOR signaling pathway, partially explaining its moderate antitumor efficacy. However, blocking lysosomal degradation with chloroquine/Bafilamycine A1 or inhibiting AMPK signaling with compound C/shPRKAA1 enhanced the ACK1 inhibitor's cytotoxic effects on lung cancer cells. The efficacy of the combined therapy was also verified using a mouse xenograft model.

CONCLUSIONS

The resulting signature from ACK1-related autophagy genes robustly predicted survival and drug sensitivity in LUAD. The lysosomal degradation inhibition improved the therapeutic effects of the ACK1 inhibitor, suggesting a potential role for autophagy in therapy evasion.

The noncatalytic regions of the tyrosine kinase Tnk1 are important for activity and substrate specificity

Human Tnk1 (thirty-eight negative kinase 1) is a member of the Ack family of nonreceptor tyrosine kinases. Tnk1 contains a sterile alpha motif, a tyrosine kinase catalytic domain, an SH3 (Src homology 3) domain, and a large C-terminal region that contains a ubiquitin association domain. However, specific physiological roles for Tnk1 have not been characterized in depth. Here, we expressed and purified Tnk1 from Sf9 insect cells and established an in vitro assay system using a peptide substrate derived from the Wiskott-Aldrich Syndrome Protein (WASP). By Tnk1 expression in mammalian cells, we found that the N-terminal SAM domain is important for self-association and kinase activity. We also studied a fusion protein, originally discovered in a Hodgkin's Lymphoma cell line, that contains an unrelated sequence from the C17ORF61 gene fused to the C-terminus of Tnk1. Cells expressing the fusion protein showed increased tyrosine phosphorylation of cellular substrates relative to cells expressing WT Tnk1. A truncated Tnk1 construct (residues 1-465) also showed enhanced phosphorylation, indicating that the C17ORF61 sequence was dispensable for the effect. Additionally, in vitro kinase assays with the WASP peptide substrate showed no increase in intrinsic Tnk1 activity in C-terminally truncated constructs, suggesting that the truncations did not simply remove an autoinhibitory element. Fluorescence microscopy experiments demonstrated that the C-terminus of Tnk1 plays an important role in the subcellular localization of the kinase. Taken together, our data suggest that the noncatalytic regions of Tnk1 play important roles in governing activity and substrate phosphorylation.

Molecular dynamics simulations reveal the activation mechanism of mutations G12V and Q61L of Cdc42

Cell division control protein 42 homolog (Cdc42), which contributes to multiple cellular processes including cell proliferation and migration, is a potential target for cancer therapy, especially in the intervention of tumor migration. Cdc42's mutants G12V and Q61L are discovered constitutively active, and the overexpression of them exhibits oncogenic activities. Here, using molecular dynamics (MD) simulations and dynamic analysis, we illustrated the activation mechanism of Cdc42^G12V and Cdc42^Q61L . Without GAP, the two mutations differently elicited state transition from the wild-type's open "inactive" state 1 to the closed "active" state 2, induced by the introduction of a newly formed water-mediated T35-γ-phosphate hydrogen bond in G12V system and the additional hydrophobic interactions between L61 and T35 together with the direct T35-γ-phosphate hydrogen bond in Q61L system. When binding with GAP, both mutations weakened the hydrogen bond interactions between Cdc42-GTP and GAP's finger loop, and disturbed the catalytically competent organizations of GAP's catalytic R305/R306 and Cdc42's Q61, thereby impairing the GAP-mediated GTP hydrolysis. Our findings first reveal the activation mechanism of Cdc42's G12V and Q61L mutants on a molecular basis, which provide new insights into the structural and dynamical characteristics of Cdc42 and its mutants and can be exploited in the further development of novel therapies targeting Cdc42-related cancers.

ACK1 Contributes to the Pathogenesis of Inflammation and Autoimmunity by Promoting the Activation of TLR Signaling Pathways

Toll-like receptors (TLRs) are the first line of defense in the immune system, whose activation plays a key role in the pathogenesis of inflammation and autoimmunity. TLRs can activate a variety of immune cells such as macrophages and dendritic cells, which produce proinflammatory cytokines, chemokines, and co-stimulatory molecules that lead to the development of inflammation and autoimmune diseases. As a nonreceptor tyrosine kinase, ACK1 is involved in multiple signaling pathways and physiological processes. However, the roles of ACK1 in the activation of TLR pathways and in the pathogenesis of inflammation and autoimmune diseases have not yet been reported. We found that the expression of ACK1 could be upregulated by TLR pathways in vivo and in vitro. Intriguingly, overexpression of ACK1 significantly promoted the activation of TLR4, TLR7, and TLR9 pathways, while knockdown of ACK1 or the use of the ACK1 inhibitor AIM-100 significantly inhibited the activation of TLR4, TLR7, and TLR9 pathways. In vivo studies showed that the inhibition of ACK1 activity by AIM-100 could significantly protect mice from the TLR4 agonist lipopolysaccharide (LPS)-mediated endotoxin shock and alleviate the condition of imiquimod-mediated lupus-prone mice and MRL/lpr mice. In summary, ACK1 participates in TLR-mediated inflammation and autoimmunity and has great potential in controlling inflammation and alleviating autoimmune diseases.

The Mechanism of Long Non-coding RNA in Cancer Radioresistance/Radiosensitivity: A Systematic Review

Background and purpose: Radioresistance remains a significant challenge in tumor therapy. This systematic review aims to demonstrate the role of long non-coding RNA (lncRNA) in cancer radioresistance/radiosensitivity.

Material and methods: The electronic databases Pubmed, Embase, and Google Scholar were searched from January 2000 to December 2021 to identify studies addressing the mechanisms of lncRNAs in tumor radioresistance/sensitivity, each of which required both in vivo and in vitro experiments.

Results: Among the 87 studies identified, lncRNAs were implicated in tumor radioresistance/sensitivity mainly in three paradigms. 1) lncRNAs act on microRNA (miRNA) by means of a sponge, and their downstream signals include some specific molecular biological processes (DNA repair and chromosome stabilization, mRNA or protein stabilization, cell cycle and proliferation, apoptosis-related pathways, autophagy-related pathways, epithelial-mesenchymal transition (EMT), cellular energy metabolism) and some signaling mediators (transcription factors, kinases, some important signal transduction pathways) that regulate various biological processes. 2) lncRNAs directly interact with proteins, affecting the cell cycle and autophagy to contribute to tumor radioresistance. 3) lncRNAs act like transcription factors to initiate downstream signaling pathways and participate in tumor radioresistance.

Conclusion: lncRNAs are important regulators involved in tumor radioresistance\sensitivity. Different lncRNAs may participate in the radioresistance with the same regulatory paradigm, and the same lncRNAs may also participate in the radioresistance in different ways. Future research should focus more on comprehensively characterizing the mechanisms of lncRNAs in tumor radioresistance to help us identify corresponding novel biomarkers and develop new lncRNA-based methods to improve radioresistance.

Chemical Reactivity and Optical and Pharmacokinetics Studies of 14 Multikinase Inhibitors and Their Docking Interactions Toward ACK1 for Precision Oncology

Activated Cdc42-associated kinase 1 (ACK1/TNK2) has a significant role in cell endocytosis, survival, proliferation, and migration. Mutations in ACK1 are closely associated with the occurrence and development of cancers. In this work, a conceptual density functional theory (CDFT)-based computational peptidology (CDFT-CP) method is used to study the chemical reactivity of 14 multikinase inhibitors. Optical properties of these inhibitors are studied by time-dependent density functional theory (TDDFT). Various biological and pharmacokinetic parameters are studied by Osiris, Molinspiration, and BOILED-Egg in SwissADME software tools. Physicochemical and biopharmaceutical (PCB), Salmonella typhimurium reverse mutation assay (AMES) mutagenicity, toxicity, and risk prediction are estimated by Simulations plus ADMET Predictor 10.2 software. MD simulations for an active model of ACK1 is carried out by the CABS-flex 2.0 web server, and potential binding pockets for ACK1 are searched using the PrankWeb server. SwissTargetPrediction is used to predict the potential targets for the multikinase inhibitors. Docking studies are carried out for ACK1–multikinase inhibitors using Autodock 4.2 software. Noncovalent interactions for ACK1–multikinase inhibitor complexes are studied using the Protein–Ligand Interaction Profiler (PLIP) server. Results indicated higher binding affinities and strong noncovalent interactions in ACK1–multikinase inhibitor complexes.

Identification of an ACK1/TNK2-based prognostic signature for colon cancer to predict survival and inflammatory landscapes

Activated Cdc42-associated kinase 1 (ACK1), a kind of tyrosine kinase, is considered to be an oncogene in many cancers, and it is likely to become a potential target for cancer treatment. We found that the expression of the ACK1 gene in colon cancer was higher than that in normal tissues adjacent to cancer, and high expression of the ACK1 gene was associated with poor prognosis of patients. We assessed the prognosis of colon cancer based on ACK1-related genes and constructed a model that can predict the prognosis of colon cancer patients in colon cancer data from The Cancer Genome Atlas (TCGA) database. We then explored the relationship between ACK1 and the immune microenvironment of colon cancer. The overexpression of ACK1 might hinder the function of antigen-presenting cells. The colon cancer prognosis prediction model we constructed has certain significance for clinicians to judge the prognosis of patients with colon cancer. The expression of the ACK1 gene might affect the infiltration level of a variety of immune cells and immunomodulators in the immune microenvironment.

Small Molecules Targeting Activated Cdc42-Associated Kinase 1 (ACK1/TNK2) for the Treatment of Cancers

Activated Cdc42-associated kinase 1 (ACK1/TNK2) is a nonreceptor tyrosine kinase with a unique structure. It not only can act as an activated transmembrane effector of receptor tyrosine kinases (RTKs) to transmit various RTK signals but also can play a corresponding role in epigenetic regulation. A number of studies have shown that ACK1 is a carcinogenic factor. Blockage of ACK1 has been proven to be able to inhibit cancer cell survival, proliferation, migration, and radiation resistance. Thus, ACK1 is a promising potential antitumor target. To date, despite many efforts to develop ACK1 inhibitors, no specific small molecule inhibitors have entered clinical trials. This Perspective provides an overview of the structural features, biological functions, and association with diseases of ACK1 and in vitro and in vivo activities, selectivity, and therapeutic potential of small molecule ACK1 inhibitors with different chemotypes.

Progress in the therapeutic inhibition of Cdc42 signalling

Cdc42 is a member of the Rho family of small GTPases and a key regulator of the actin cytoskeleton, controlling cell motility, polarity and cell cycle progression. It signals downstream of the master regulator Ras and is essential for cell transformation by this potent oncogene. Overexpression of Cdc42 is observed in several cancers, where it is linked to poor prognosis. As a regulator of both cell architecture and motility, deregulation of Cdc42 is also linked to tumour metastasis. Like Ras, Cdc42 and other components of the signalling pathways it controls represent important potential targets for cancer therapeutics. In this review, we consider the progress that has been made targeting Cdc42, its regulators and effectors, including new modalities and new approaches to inhibition. Strategies under consideration include inhibition of lipid modification, modulation of Cdc42-GEF, Cdc42-GDI and Cdc42-effector interactions, and direct inhibition of downstream effectors.

Combined inhibition of ACK1 and AKT shows potential toward targeted therapy against KRAS-mutant non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) with Kirsten RAt Sarcoma 2 viral oncogene homolog (KRAS) mutation has become a clinical challenge in cancer treatment as KRAS-mutant tumors are often resistant to conventional anti-tumor therapies. Activated CDC42-associated kinase 1 (ACK1), an activator of protein kinase B (AKT), is a promising target for KRAS-mutant tumor therapy, but the downstream ACK1 signaling remains poorly understood. The aim of this study was to evaluate the effectiveness of combined ACK1/AKT inhibition on the proliferation, migration, invasion, and apoptosis of KRAS-mutant NSCLC cell lines (NCI-H23, NCI-H358, and A549). The cells were treated with an inhibitor of either ACK1 (dasatinib or sunitinib) or AKT (MK-2206 or GDC-0068), and the optimal concentrations of the two yielding synergistic tumor-killing effects were determined by applying the Chou-Talalay equation for drug combinations. We showed that combined administration of ACK1 and AKT inhibitors at the optimal concentrations effectively suppressed NSCLC cell viability and promoted apoptosis while inducing cell cycle arrest at the G2 phase. Moreover, NSCLC cell migration and invasion were inhibited by combined ACK1/AKT inhibition. These phenomena were associated with the reduced phosphorylation levels of ACK1 and AKT (at Ser473 and Thr308), as well as alterations in caspase-dependent apoptotic signaling. Collectively, our results demonstrate the promising therapeutic potential of combined ACK1/AKT inhibition as a strategy against KRAS-mutant NSCLC. Our findings provide the basis for the clinical translation of biological targeted drugs (ACK1 and AKT inhibitors) and their rational combination in cancer treatment.

TNK2 promoted esophageal cancer progression via activating egfr-akt signaling

Background

This study investigated the clinical implication of TNK2 expression in esophageal cancer patients’ cancer tissue samples.

Methods

The expression of TNK2 in esophageal cancer tissues and para‐carcinoma tissue was assessed with immunohistochemistry and Western blot analysis; besides, the proteins of CDC42, EGFR, and Akt were also analyzed. Then, Kaplan‐Meier survival curves of TNK2 protein expression level were assayed with 184 esophageal cancer patients from TCGA database. Moreover, with multiple linear regression analysis, we detected the correlations of TNK2 expression associated with tumor differentiation degree and metastasis status.

Results

It revealed that TNK2 was highly expressed in the cytoplasm of esophageal cancer tissues compared with para‐carcinoma tissue; besides, the proteins of CDC42, EGFR, and Akt were also up‐regulated in different levels of esophageal cancer tissues. However, there was no significant difference of the overall survival time of TNK2 protein expression in 184 esophageal cancer patients from TCGA database (p = 0.37). But, in the included study samples of our study, there was positive coefficience between TNK2 protein expression and differentiation degree in esophageal cancer with multiple linear regression analysis [R = 0.928, 95% confidence interval (0.085‐0.12)].

Conclusion

Our results indicated that TNK2 was a potential diagnostic marker and promoted esophageal cancer progression through activating EGFR‐AKT signaling.

Identification of downstream signaling cascades of ACK1 and prognostic classifiers in non-small cell lung cancer

Activated Cdc42-associated kinase 1 (ACK1) is an oncogene in multiple cancers, but the underlying mechanisms of its oncogenic role remain unclear in non-small cell lung cancer (NSCLC). Herein, we comprehensively investigated the ACK1-regulated cell processes and downstream signaling pathways, as well as its prognostic value in NSCLC. We found that ACK1 gene amplification was associated with mRNA levels in The Cancer Genome Atlas (TCGA) lung cancer cohort. The Oncomine databases showed significantly elevated ACK1 levels in lung cancer. In vitro, an ACK1 inhibitor (dasatinib) increased the sensitivity of NSCLC cell lines to AKT or MEK inhibitors. RNA-sequencing results demonstrated that an ACK1 deficiency in A549 cells affected the MAPK, PI3K/AKT, and Wnt pathways. These results were validated by gene set enrichment analysis (GSEA) of data from 188 lung cancer cell lines. Using Cytoscape, we dissected 14 critical ACK1-regulated genes. The signature with the 14 genes and ACK1 could significantly dichotomize the TCGA lung cohort regarding overall survival. The prognostic accuracy of this signature was confirmed in five independent lung cancer cohorts and was further validated by a prognostic nomogram. Our study unveiled several downstream signaling pathways for ACK1, and the proposed signature may be a promising prognostic predictor for NSCLC.

Bioinformatics analysis identified shared differentially expressed genes as potential biomarkers for Hashimoto's thyroiditis-related papillary thyroid cancer

Background: Although the etiology of Hashimoto's thyroiditis (HT), a common autoimmune endocrine disease, is unknown, studies suggest a potential association with genetic factors and environmental conditions inducing excessive iodine intake. Additionally, HT patients have a high risk of papillary thyroid cancer (PTC), which is probably related to the chronic inflammation and autoimmune pathologic process occurring in HT, as it is thought to be associated with neoplastic transformation. Methods: Bioinformatics approaches can identify differentially expressed genes (DEGs) and analyze DEG functions in diseases. R software was used in this study to identify DEGs in HT and PTC using data in Gene Expression Omnibus (GEO). The online tools DAVID, Reactome, and AmiGO were employed for annotation, visualization, and integration of DEGs related to HT and PTC, and the STRING database and Cytoscape software were applied to predict and visualize protein-protein networks (PPIs) for DEG-encoded proteins. Coexpressed DEGs in HT and PTC were validated by reverse transcription PCR (RT-PCR). Results: In total, 326, 231, and 210 DEGs in HT specimens and samples of central PTC and PTC invasive areas, respectively, were detected. According to the PPI network, PTPN6, HLA-A, C3AR1, LCK and ITGB2 are hub genes among HT-DEGs, whereas FN1, CDH2, SERPINA1, and CYR61 are PTC-DEG hub genes. The shared DEGs LTF and CCL21 were validated by RT-PCR. Both bioinformatics and RT-PCR analyses showed LTF and CCL21 to be upregulated in HT tissues and downregulated in PTC tissues. Conclusions: We identified that expression of LTF and CCL21 are significantly different in HT and PTC, suggesting an underlying association between HT and PTC.

Discovery of a series of benzopyrimidodiazepinone TNK2 inhibitors via scaffold morphing

The protein kinase TNK2 (ACK1) is an emerging drug target for a variety of indications, in particular for cancer where it plays a key role transmitting cell survival, growth and proliferative signals via modification of multiple downstream effectors by unique tyrosine phosphorylation events. Scaffold morphing based on our previous TNK2 inhibitor XMD8-87 identified urea 17 from which we developed the potent and selective compound 32. A co-crystal structure was obtained showing 32 interacting primarily with the main chain atoms of an alanine residue of the hinge region. Additional H-bonds exist between the urea NHs and the Thr205 and Asp270 residues.

Inhibition of ACK1 delays and overcomes acquired resistance of EGFR mutant NSCLC cells to the third generation EGFR inhibitor, osimertinib

OBJECTIVES

The emergence of acquired resistance to the third generation EGFR inhibitor, osimertinib (AZD9291 or TAGRISSO™), is an unavoidable huge clinical challenge. The involvement of ACK1, a non-receptor tyrosine kinase with an oncogenic function, in regulating cell response to osimertinib has not been investigated and thus is the focus of this study.

MATERIAL AND METHODS

Drug effects on cell growth were evaluated by measuring cell numbers and colony formation. Apoptosis was monitored with flow cytometry for annexin V-positive cells and Western blotting for protein cleavage. Intracellular protein and mRNA alterations were detected with Western blotting and qRT-PCR, respectively. Drug effects on delaying osimertinib acquired resistance were determined using colony formation in vitro and xenografts in nude mice in vivo, respectively. Cell senescence was assayed by β-galactosidase staining.

RESULTS

Inhibition of ACK1 with the novel ACK1 inhibitor, (R)-9b synergized with osimertinib in inhibiting the growth of EGFR mutant NSCLC cell lines. Similar results were also generated with ACK1 gene knockdown. The combination of osimertinib and (R)-9b enhanced induction of apoptosis. In both in vitro and in vivo long-term resistance delay assays, the combination of (R)-9b and osimertinib clearly delayed the emergence of osimertinib-resistance. Further, the (R)-9b and osimertinib combination was also effective in inhibiting the growth of EGFR mutant NSCLC cell lines with acquired resistance to osimertinib, which possess elevated levels of ACK1, and the growth of osimertinib-resistant tumors in vivo. In some resistant cell lines, the combinations induced senescence in addition to induction of apoptosis.

CONCLUSIONS

These novel findings suggest that ACK1 inhibition might be a potential and innovative strategy for delaying and overcoming osimertinb acquired resistance.

Discovery of a novel third-generation EGFR inhibitor and identification of a potential combination strategy to overcome resistance

BACKGROUND

Non-small cell lung cancer (NSCLC) patients with activating EGFR mutations initially respond to first-generation EGFR inhibitors; however, the efficacy of these drugs is limited by acquired resistance driven by the EGFR T790M mutation. The discovery of third-generation EGFR inhibitors overcoming EGFR T790M and their new resistance mechanisms have attracted much attention.

METHODS

We examined the antitumor activities and potential resistance mechanism of a novel EGFR third-generation inhibitor in vitro and in vivo using ELISA, SRB assay, immunoblotting, flow cytometric analysis, kinase array, qRT-PCR and tumor xenograft models. The clinical effect on a patient was evaluated by computed tomography scan.

RESULTS

We identified compound ASK120067 as a novel inhibitor of EGFR T790M, with selectivity over EGFR WT. ASK120067 exhibited potent anti-proliferation activity in tumor cells harboring EGFR T790M (NCI-H1975) and sensitizing mutations (PC-9 and HCC827) while showed moderate or weak inhibition in cells expressing EGFR WT. Oral administration of ASK120067 induced tumor regression in NSCLC xenograft models and in a PDX model harboring EGFR T790M. The treatment of one patient with advanced EGFR T790M-positive NSCLC was described as proof of principle. Moreover, we found that hyperphosphorylation of Ack1 and the subsequent activation of antiapoptotic signaling via the AKT pathway contributed to ASK120067 resistance. Concomitant targeting of EGFR and Ack1 effectively overrode the acquired resistance of ASK120067 both in vitro and in vivo.

CONCLUSIONS

Our results idenfity ASK120067 as a promising third-generation EGFR inhibitor and reveal for the first time that Ack1 activation as a novel resistance mechanism to EGFR inhibitors that guide to potential combination strategy.

Targeted inhibition of ACK1 can inhibit the proliferation of hepatocellular carcinoma cells through the PTEN/AKT/mTOR pathway

Activated Cdc42-associated kinase 1 (ACK1) expression is upregulated in hepatocellular carcinoma (HCC) tissues and other tumour tissues. However, the function and regulatory mechanism of ACK1 in HCC remains unclear. In this study, the expression of pTyr284-ACK1, pSer473-AKT and PTEN in HCC was detected by immunohistochemistry, and its clinicopathological significance was analysed. Then, ACK1-targeted small molecule inhibitors AIM-100 and Dasatinib were used to treat cells SK-Hep-1 and HepG2, and changes in activity and biological behaviours of PTEN/AKT/mTOR signalling pathway were observed. The results showed that pTyr284-ACK1 protein was highly expressed in HCC tissues and was related to the poor prognosis of patients; the expression of pTyr284-ACK1 protein was positively correlated with pSer473-AKT and negatively correlated with PTEN. In addition, after treatment either with AIM-100 or Dasatinib, both proliferation of two cells and migration, invasion of SK-Hep-1 cells were all significantly inhibited. Meanwhile, ACK1, pTyr284-ACK1, pSer473-AKT, mTOR and EGFR were down-regulated; PTEN was up-regulated when analysed by western-blot in SK-Hep-1 cells. These results demonstrated that ACK1 may promote HCC development via PTEN/AKT/mTOR pathway. Targeted inhibition of ACK1 may be a novel therapeutic strategy for HCC. SIGNIFICANCE OF THE STUDY: Hepatocellular carcinoma (HCC) is a common malignant tumour with high mortality. Our study showed that ACK1 and pTyr284-ACK1 are highly expressed in HCC and may promote HCC development through the PTEN/AKT/mTOR signalling pathway. Targeted inhibition of ACK1 expression with small inhibitors AIM-100 and Dasatinib may weaken tumour cells ability of proliferation, migration and invasion. Our results suggested that downregulation of ACK1 may be a potential therapeutic strategy for HCC.

Alterations in Tight- and Adherens-Junction Proteins Related to Glaucoma Mimicked in the Organotypically Cultivated Mouse Retina Under Elevated Pressure

Purpose

To scrutinize alterations in cellular interactions and cell signaling in the glaucomatous retina, mouse retinal explants were exposed to elevated pressure.

Methods

Retinal explants were prepared from C57bl6 mice and cultivated in a pressure chamber under normotensive (atmospheric pressure + 0 mm Hg), moderately elevated (30 mm Hg), and highly elevated (60 mm Hg) pressure conditions. The expression levels of proteins involved in the formation of tight junctions (zonula occludens 1 [ZO-1], occludin, and claudin-5) and adherens junctions (VE-cadherin and β-catenin) and in cell-signaling cascades (Cdc42 and activated Cdc42 kinase 1 [ACK1]), as well as the expression levels of the growth-factor receptors platelet-derived growth factor receptor beta and vascular endothelial growth factor receptors 1 and 2 (VEGFR-1, VEGFR-2) and of diverse intracellular proteins (β-III-tubulin, glial fibrillary acidic protein transcript variant 1, α-smooth muscle actin, vimentin, and von Willebrand factor VIII), were analyzed using immunohistochemistry, western blotting, and quantitative real-time polymerase chain reactions.

Results

The retinal explants were well preserved when cultured in the pressure chambers used in this study. The responses to pressure elevation varied among diverse retinal cells. Under elevated pressure, the expression of ZO-1 increased in the large vessels, neuronal cells began to express VEGFR-1, and the Cdc42 expression in the optic nerve head was downregulated. Overall we found significant transcriptional downregulation of VE-cadherin, β-catenin, VEGFR-1, VEGFR-2, vimentin, Cdc42, and ACK1. Western blotting and immunohistochemistry indicated a loss of VE-cadherin with pressure elevation, whereas the protein levels of ZO-1, occludin, VEGFR-1, and ACK1 increased.

Conclusions

The pressure chamber used for cultivating mouse retinal explants can serve as an in vitro model system for investigating molecular alterations in glaucoma. In this system, responses of the entire retinal cells toward elevated pressure with conspicuous changes in the vasculature and the optic nerve head can be seen. In particular, our investigations indicate that changes in the blood–retina barrier and in cellular signaling are induced by pressure elevation.

Research Progress of the Functional Role of ACK1 in Breast Cancer

ACK1 is a nonreceptor tyrosine kinase with a unique structure, which is tightly related to the biological behavior of tumors. Previous studies have demonstrated that ACK1 was involved with multiple signaling pathways of tumor progression. Its crucial role in tumor cell proliferation, apoptosis, invasion, and metastasis was tightly related to the prognosis and clinicopathology of cancer. ACK1 has a unique way of regulating cellular pathways, different from other nonreceptor tyrosine kinases. As an oncogenic kinase, recent studies have shown that ACK1 plays a critical regulatory role in the initiation and progression of tumors. In this review, we will be summarizing the structural characteristics, activation, and regulation of ACK1 in breast cancer, aiming to deeply understand the functional and mechanistic role of ACK1 and provide novel therapeutic strategies for breast cancer treatment.

p66Shc protein through a redox mechanism enhances the progression of prostate cancer cells towards castration-resistance

Prostate cancer (PCa) remains the second leading cause of cancer-related deaths in U.S. men due to the development of the castration-resistant (CR) PCa phenotype. A useful cell model for analysis of the molecular mechanism of PCa progression is required for developing targeted therapies toward CR PCa. In this study, we established a PCa cell progressive model in three separate cell lines, of which androgen-independent (AI) cells were derived from respective androgen-sensitive (AS) cells. Those AI PCa cells obtain the biochemical properties of the clinical CR phenotype, including AR and PSA expression as well as enhanced proliferation and tumorigenicity under androgen-deprived conditions. Thus, those AI cells recapitulate CR PCa and exhibit increased oxidant species levels as well as enhanced signaling of proliferation and survival pathways. H2O2 treatment directly enhanced AS cell growth and migration, which was counteracted by antioxidant N-acetyl cysteine (NAC). We further identified p66Shc protein enhances the production of oxidant species which contributes to phenotypic and cell signaling alterations from AS to AI PCa cells. H2O2-treated LNCaP-AS cells had a similar signaling profile to that of LNCaP-AI or p66Shc subclone cells. Conversely, the oxidant species-driven alterations of LNCaP-AI and p66Shc subclone cell signaling is mitigated by p66Shc knockdown. Moreover, LNCaP-AI cells and p66Shc subclones, but not LNCaP-AS cells, develop xenograft tumors with metastatic nodules, correlating with p66Shc protein levels. Together, the data shows that p66Shc enhances oxidant species production that plays a role in promoting PCa progression to the CR stage.

Targeting Rac and Cdc42 GTPases in Cancer

Rac and Cdc42 are small GTPases that have been linked to multiple human cancers and are implicated in epithelial to mesenchymal transition, cell-cycle progression, migration/invasion, tumor growth, angiogenesis, and oncogenic transformation. With the exception of the P29S driver mutation in melanoma, Rac and Cdc42 are not generally mutated in cancer, but are overexpressed (gene amplification and mRNA upregulation) or hyperactivated. Rac and Cdc42 are hyperactivated via signaling through oncogenic cell surface receptors, such as growth factor receptors, which converge on the guanine nucleotide exchange factors that regulate their GDP/GTP exchange. Hence, targeting Rac and Cdc42 represents a promising strategy for precise cancer therapy, as well as for inhibition of bypass signaling that promotes resistance to cell surface receptor-targeted therapies. Therefore, an understanding of the regulatory mechanisms of these pivotal signaling intermediates is key for the development of effective inhibitors. In this review, we focus on the role of Rac and Cdc42 in cancer and summarize the regulatory mechanisms, inhibitory efficacy, and the anticancer potential of Rac- and Cdc42-targeting agents. Cancer Res; 78(12); 3101-11. ©2018 AACR.

Actin organization and endocytic trafficking are controlled by a network linking NIMA-related kinases to the CDC-42-SID-3/ACK1 pathway

Molting is an essential process in the nematode Caenorhabditis elegans during which the epidermal apical extracellular matrix, termed the cuticle, is detached and replaced at each larval stage. The conserved NIMA-related kinases NEKL-2/NEK8/NEK9 and NEKL-3/NEK6/NEK7, together with their ankyrin repeat partners, MLT-2/ANKS6, MLT-3/ANKS3, and MLT-4/INVS, are essential for normal molting. In nekl and mlt mutants, the old larval cuticle fails to be completely shed, leading to entrapment and growth arrest. To better understand the molecular and cellular functions of NEKLs during molting, we isolated genetic suppressors of nekl molting-defective mutants. Using two independent approaches, we identified CDC-42, a conserved Rho-family GTPase, and its effector protein kinase, SID-3/ACK1. Notably, CDC42 and ACK1 regulate actin dynamics in mammals, and actin reorganization within the worm epidermis has been proposed to be important for the molting process. Inhibition of NEKL-MLT activities led to strong defects in the distribution of actin and failure to form molting-specific apical actin bundles. Importantly, this phenotype was reverted following cdc-42 or sid-3 inhibition. In addition, repression of CDC-42 or SID-3 also suppressed nekl-associated defects in trafficking, a process that requires actin assembly and disassembly. Expression analyses indicated that components of the NEKL-MLT network colocalize with both actin and CDC-42 in specific regions of the epidermis. Moreover, NEKL-MLT components were required for the normal subcellular localization of CDC-42 in the epidermis as well as wild-type levels of CDC-42 activation. Taken together, our findings indicate that the NEKL-MLT network regulates actin through CDC-42 and its effector SID-3. Interestingly, we also observed that downregulation of CDC-42 in a wild-type background leads to molting defects, suggesting that there is a fine balance between NEKL-MLT and CDC-42-SID-3 activities in the epidermis.

Role of Non Receptor Tyrosine Kinases in Hematological Malignances and its Targeting by Natural Products

Tyrosine kinases belong to a family of enzymes that mediate the movement of the phosphate group to tyrosine residues of target protein, thus transmitting signals from the cell surface to cytoplasmic proteins and the nucleus to regulate physiological processes. Non-receptor tyrosine kinases (NRTK) are a sub-group of tyrosine kinases, which can relay intracellular signals originating from extracellular receptor. NRTKs can regulate a huge array of cellular functions such as cell survival, division/propagation and adhesion, gene expression, immune response, etc. NRTKs exhibit considerable variability in their structural make up, having a shared kinase domain and commonly possessing many other domains such as SH2, SH3 which are protein-protein interacting domains. Recent studies show that NRTKs are mutated in several hematological malignancies, including lymphomas, leukemias and myelomas, leading to aberrant activation. It can be due to point mutations which are intragenic changes or by fusion of genes leading to chromosome translocation. Mutations that lead to constitutive kinase activity result in the formation of oncogenes, such as Abl, Fes, Src, etc. Therefore, specific kinase inhibitors have been sought after to target mutated kinases. A number of compounds have since been discovered, which have shown to inhibit the activity of NRTKs, which are remarkably well tolerated. This review covers the role of various NRTKs in the development of hematological cancers, including their deregulation, genetic alterations, aberrant activation and associated mutations. In addition, it also looks at the recent advances in the development of novel natural compounds that can target NRTKs and perhaps in combination with other forms of therapy can show great promise for the treatment of hematological malignancies.

Identification of novel Ack1-interacting proteins and Ack1 phosphorylated sites in mouse brain by mass spectrometry

Ack1 (activated Cdc42-associated tyrosine kinase) is a non-receptor tyrosine kinase that is highly expressed in brain. This kinase contains several protein-protein interaction domains and its action is partially regulated by phosphorylation. As a first step to address the neuronal functions of Ack1, here we screened mouse brain samples to identify proteins that interact with this kinase. Using mass spectrometry analysis, we identified new putative partners for Ack1 including cytoskeletal proteins such as Drebrin or MAP4; adhesion regulators such as NCAM1 and neurabin-2; and synapse mediators such as SynGAP, GRIN1 and GRIN3. In addition, we confirmed that Ack1 and CAMKII both co-immunoprecipitate and co-localize in neurons. We also identified that adult and P5 samples contained the phosphorylated residues Thr 104 and Ser 825, and only P5 samples contained phosphorylated Ser 722, a site linked to cancer and interleukin signaling when phosphorylated. All these findings support the notion that Ack1 could be involved in neuronal plasticity.

Amplification of ACK1 promotes gastric tumorigenesis via ECD-dependent p53 ubiquitination degradation

Amplification or over-expression of an activated Cdc42-associated kinase 1 (ACK1) gene is common in breast, lung and ovarian cancers. However, little is known about the role of ACK1 in gastric tumorigenesis. Here, we found that DNA copy numbers of the ACK1 gene and its mRNA expression levels were significantly increased in gastric cancer (GC) compared to normal gastric tissues. Additionally, silencing ACK1 inhibited GC cell proliferation and colony formation, induced G2/M arrest and cellular apoptosis in vitro, and suppressed tumor growth in vivo. Gene Ontology annotation revealed that 147 differential proteins regulated by ACK1 knockdown were closely related with cellular survival. A cell cycle regulator, ecdysoneless homolog (ECD), was found to be significantly down-regulated by ACK1 knockdown. Silencing of ECD inhibited colony formation and induced G2/M arrest and cell apoptosis, which is similar to the effects of ACK1 knockdown. Silencing of ECD did not further enhance the effects of ACK1 knockdown on G2/M arrest and apoptosis, while silencing of ECD blocked the enhancement of colony formation by ACK1 over-expression. Over-expression of ACK or ECD promoted the ubiquitination of tumor suppressor p53 protein and decreased p53 levels, while silencing of ACK1 or ECD decreased the p53 ubiquitination level and increased p53 levels. Silencing of ECD attenuated the ubiquitination enhancement of p53 induced by ACK1 over-expression. Collectively, we demonstrate that amplification of ACK1 promotes gastric tumorigenesis by inducing an ECD-dependent ubiquitination degradation of p53.

miR-24 represses metastasis of human osteosarcoma cells by targeting Ack1 via AKT/MMPs pathway

The expression levels of the protein tyrosine kinase Ack1 has been reported to be dysregulated in various cancers and involve in oncogenesis and progression. However, the expression and role of Ack1 in osteosarcoma remains unknown. In this study, we found that Ack1 were evidently upregulated in human osteosarcoma tissues and cell lines. In addition, the clinical data showed that high expression level of Ack1 is closely associated with clinical stage and positive distant metastasis, and negatively correlated with overall survival. Then, bioinformatics prediction and luciferase reporter assay indicated Ack1 as a direct target of miR-24, and Ack1 could be downregulated by miR-24 at both the mRNA and protein expression levels. Moreover, Ack1 expression levels were inversely correlated with that of miR-24 in osteosarcoma tissues. Furthermore, functional assay showed that miR-24 significantly suppressed osteosarcoma progression partially mediated by inhibiting Ack1 expression. Finally, western bolt assay revealed that miR-24 regulate AKT/MMPs pathway via Ack1 in osteosarcoma cells. In conclusion, our study demonstrated the suppression of miR-24 on osteosarcoma metastasis by targeting Ack1 via AKT/MMPs pathways, providing a novel strategy for the diagnosis and treatment of osteosarcoma patients.

Involvement of Activated Cdc42 Kinase1 in Colitis and Colorectal Neoplasms

BACKGROUND Activated Cdc42 kinase1 (ACK1) is a non-receptor tyrosine kinase which is critical for cell survival, proliferation, and migration. Genomic amplification of ACK1 has been reported in multiple human cancers. We aimed to investigate ACK1 protein expression in colorectal mucosa with inflammation and neoplasm, and to evaluate its correlation with disease activity and severity. MATERIAL AND METHODS A total of 250 individuals who underwent total colonoscopy were collected randomly from January 2007 to May 2013 in Nanfang Hospital, Guangzhou, China. Colorectal mucosal biopsy specimens were obtained by endoscopy from 78 patients with ulcerative colitis (UC), 22 with Crohn's disease (CD), 20 with infectious colitis, 26 with non-IBD and noninfectious colitis, 16 with sporadic adenomas, 4 with dysplasia-associated lesions or masses, 10 with sporadic colorectal cancer (CRC), 4 with UC-related CRC, 10 with hyperplastic polyps, and 60 without colonic abnormalities. ACK1 protein levels were determined immunohistochemically. The correlations of ACK1 expression with disease activity and severity were also evaluated. RESULTS Significantly increased ACK1 expression was observed in epithelial cells of colorectal mucosa with inflammation and dysplasia compared to controls (P<0.05). ACK1 expression correlated with clinical activity in IBD (χ²=4.57, P=0.033 for UC; χ²=5.68, P=0.017 for CD), as well as grade of dysplasia in preneoplastic lesions (P<0.05). No significant differences in ACK1 expression were found between UC and CD, or between IBD and non-IBD conditions (P>0.05). CONCLUSIONS ACK1 protein is increased extensively in colitis and colorectal dysplasia. ACK1 overexpression may play a role in colorectal inflammation and neoplasms.

Activated Cdc42 kinase 1 and hepatocellular carcinoma

Primary liver cancer includes hepatocellular carcinoma (HCC) and cholangiocellular carcinoma. The incidence of HCC is different between countries and regions. As one of the common malignant tumors in China, HCC has high mortality and is the second most common cause of cancer-related death. Elucidating the molecular mechanism of HCC pathogenesis is important for the diagnosis and treatment of liver cancer in China. The expression of activated Cdc42 kinase 1 (ACK1) has been found in a variety of cancers, and ACK1 participates in the occurrence and development of cancers. However, there are currently few studies about the relationship between ACK1 protein and HCC. This paper reviews the structure characteristics and biological function of ACK1 as well as its relationship with invasion and metastasis of HCC.

APRIL and BCMA promote human multiple myeloma growth and immunosuppression in the bone marrow microenvironment

Here we show that overexpression or activation of B-cell maturation antigen (BCMA) by its ligand, a proliferation-inducing ligand (APRIL), promotes human multiple myeloma (MM) progression in vivo. BCMA downregulation strongly decreases viability and MM colony formation; conversely, BCMA overexpression augments MM cell growth and survival via induction of protein kinase B (AKT), MAPK, and nuclear factor (NF)-κB signaling cascades. Importantly, BCMA promotes in vivo growth of xenografted MM cells harboring p53 mutation in mice. BCMA-overexpressing tumors exhibit significantly increased CD31/microvessel density and vascular endothelial growth factor compared with paired control tumors. These tumors also express increased transcripts crucial for osteoclast activation, adhesion, and angiogenesis/metastasis, as well as genes mediating immune inhibition including programmed death ligand 1, transforming growth factor β, and interleukin 10. These target genes are consistently induced by paracrine APRIL binding to BCMA on MM cells, which is blocked by an antagonistic anti-APRIL monoclonal antibody hAPRIL01A (01A). 01A is cytotoxic against MM cells even in the presence of protective bone marrow (BM) myeloid cells including osteoclasts, macrophages, and plasmacytoid dendritic cells. 01A further decreases APRIL-induced adhesion and migration of MM cells via blockade of canonical and noncanonical NF-κB pathways. Moreover, 01A prevents in vivo MM cell growth within implanted human bone chips in SCID mice. Finally, the effect of 01A on MM cell viability is enhanced by lenalidomide and bortezomib. Taken together, these data delineate new molecular mechanisms of in vivo MM growth and immunosuppression critically dependent on BCMA and APRIL in the BM microenvironment, further supporting targeting this prominent pathway in MM.

Ack promotes tissue growth via phosphorylation and suppression of the Hippo pathway component Expanded

Non-receptor tyrosine kinase activated cdc42 kinase was reported to participate in several types of cancers in mammals. It is also believed to have an anti-apoptotic function in Drosophila. Here, we report the identification of Drosophila activated cdc42 kinase as a growth promoter and a novel Hippo signaling pathway regulator. We find that activated cdc42 kinase promotes tissue growth through modulating Yorkie activity. Furthermore, we demonstrate that activated cdc42 kinase interacts with Expanded and induces tyrosine phosphorylation of Expanded on multiple sites. We propose a model that activated cdc42 kinase negatively regulates Expanded by changing its phosphorylation status to promote tissue growth. Moreover, we show that ack genetically interacts with merlin and expanded. Thus, we identify Drosophila activated cdc42 kinase as a Hippo pathway regulator.

Mutation of androgen receptor N-terminal phosphorylation site Tyr-267 leads to inhibition of nuclear translocation and DNA binding

Reactivation of androgen receptor (AR) may drive recurrent prostate cancer in castrate patients. Ack1 tyrosine kinase is overexpressed in prostate cancer and promotes castrate resistant xenograft tumor growth and enhances androgen target gene expression and AR recruitment to enhancers. Ack1 phosphorylates AR at Tyr-267 and possibly Tyr-363, both in the N-terminal transactivation domain. In this study, the role of these phosphorylation sites was investigated by characterizing the phosphorylation site mutants in the context of full length and truncated AR lacking the ligand-binding domain. Y267F and Y363F mutants showed decreased transactivation of reporters. Expression of wild type full length and truncated AR in LNCaP cells increased cell proliferation in androgen-depleted conditions and increased colony formation. However, the Y267F mutant of full length and truncated AR was defective in stimulating cell proliferation. The Y363F mutant was less severely affected than the Y267F mutant. The full length AR Y267F mutant was defective in nuclear translocation induced by androgen or Ack1 kinase. The truncated AR was constitutively localized to the nucleus. Chromatin immunoprecipitation analysis showed that it was recruited to the target enhancers without androgen. The truncated Y267F AR mutant did not exhibit constitutive nuclear localization and androgen enhancer binding activity. These results support the concept that phosphorylation of Tyr-267, and to a lesser extent Tyr-363, is required for AR nuclear translocation and recruitment and DNA binding and provide a rationale for development of novel approaches to inhibit AR activity.

Development of novel ACK1/TNK2 inhibitors using a fragment-based approach

The tyrosine kinase ACK1, a critical signal transducer regulating survival of hormone-refractory cancers, is an important therapeutic target, for which there are no selective inhibitors in clinical trials to date. This work reports the discovery of novel and potent inhibitors for ACK1 tyrosine kinase (also known as TNK2) using an innovative fragment-based approach. Focused libraries were designed and synthesized by selecting fragments from reported ACK inhibitors to create hybrid structures in a mix and match process. The hybrid library was screened by enzyme-linked immunosorbent assay-based kinase inhibition and (33)P HotSpot assays. Systematic structure-activity relationship studies led to the identification of compound (R)-9b, which shows potent in vitro (IC50 = 56 nM, n = 3, (33)P HotSpot assay) and in vivo (IC50 < 2 μM, human cancer cell lines) ACK1 inhibition. Both (R)-9b and (S)-9b were stable in human plasma and displayed a long half-life (t(1/2) > 6 h).

ACK1 promotes gastric cancer epithelial-mesenchymal transition and metastasis through AKT-POU2F1-ECD signalling

Amplification of the activated Cdc42-associated kinase 1 (ACK1) gene is frequent in gastric cancer (GC). However, little is known about the clinical roles and molecular mechanisms of ACK1 abnormalities in GC. Here, we found that the ACK1 protein level and ACK1 phosphorylation at Tyr 284 were frequently elevated in GC and associated with poor patient survival. Ectopic ACK1 expression in GC cells induced epithelial-mesenchymal transition (EMT) and promoted migration and invasion in vitro, and metastasis in vivo; the depletion of ACK1 induced the opposite effects. We utilized SILAC quantitative proteomics to discover that the level of the cell cycle-related protein ecdysoneless homologue (ECD) was markedly altered by ACK1. Overexpression of ECD promoted EMT, migration, and invasion in GC, similar to the effects of ACK1 overexpression. Silencing of ECD completely blocked the augmentation of ACK1 overexpression-induced EMT, migration, and invasion. Mechanistically, ACK1 phosphorylated AKT at Thr 308 and Ser 473 and activated the AKT pathway to up-regulate the transcription factor POU2F1, which directly bound to the promoter region of its novel target gene ECD and thus regulated ECD expression in GC cells. Furthermore, the phosphorylation levels of AKT at Thr 308 and Ser 473 and POU2F1 and ECD levels were positively associated with ACK1 levels in clinical GC specimens. Collectively, we have demonstrated that ACK1 promotes EMT, migration, and invasion by activating AKT-POU2F1-ECD signalling in GC cells. ACK1 may be employed as a new prognostic factor and therapeutic target for GC.

ACK1 promotes hepatocellular carcinoma progression via downregulating WWOX and activating AKT signaling

Several studies have revealed that ACK1 is upregulated in various cancers and promotes tumor progression. However, the role and mechanism of ACK1 in hepatocellular carcinoma (HCC) remains unknown. In this study, the expression of ACK1 was assessed in several cell lines and 150 pairs of HCC and adjacent noncancerous liver tissues. The protein expression of p-ACK1 and WWOX were detected by immunohistochemistry to evaluate their correlation with ACK1. Flow cytometry, caspase 3/7 activity assay, BrdU cell proliferation assay, MTT assay and Transwell assay were used to detect apoptosis, proliferation, invasion and migration of HCC cells. The regulatory effect of ACK1 on WWOX, AKT, p-AKT, MMP2 and MMP9 in HCC cells was confirmed by immuno-blotting. We found that ACK1 was more highly expressed in HCC tissues than in non-HCC tissues, and over-expression of ACK1 was correlated with clinicopathological features of poor prognosis. Clinical analysis demonstrated that ACK1 is an independent prognostic marker for predicting overall survival and disease-free survival of HCC patients. Pearson's correlation coefficient analysis indicated that ACK1 was positively associated with p-ACK1 and was negatively associated with WWOX expression. In vitro studies showed that knockdown of ACK1 promoted HCC cell apoptosis and repressed HCC cells invasion, migration and proliferation. Furthermore, knockdown of ACK1 resulted in upregulation of WWOX and inactivation of AKT signaling. In this study, we also found that knockdown of ACK1 resulted in the downregulation of MMP2 and MMP9 in HCC. Our results indicate that ACK1 is an independent prognostic marker and promotes HCC progression via downregulating WWOX and activating AKT signaling.

Global transcriptomic analysis of model human cell lines exposed to surface-modified gold nanoparticles: the effect of surface chemistry

Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how Au NPs and their surface coatings may impact cellular gene expression. The gene expression of two model human cell lines, human dermal fibroblasts (HDF) and prostate cancer cells (PC3) was interrogated by microarray analysis of over 14,000 human genes. The cell lines were exposed to four differently functionalized Au NPs: citrate, poly(allylamine hydrochloride) (PAH), and lipid coatings combined with alkanethiols or PAH. Gene functional annotation categories and weighted gene correlation network analysis were used in order to connect gene expression changes to common cellular functions and to elucidate expression patterns between Au NP samples. Coated Au NPs affect genes implicated in proliferation, angiogenesis, and metabolism in HDF cells, and inflammation, angiogenesis, proliferation apoptosis regulation, survival and invasion in PC3 cells. Subtle changes in surface chemistry, such as the initial net charge, lability of the ligand, and underlying layers greatly influence the degree of expression change and the type of cellular pathway affected.

The molecular mechanisms and therapeutic potential of microRNA-7 in cancer

INTRODUCTION

Increasing evidence supports that microRNAs (miRNAs) play crucial roles in cancer through post-transcriptional gene silencing of their target genes, therefore, more and more effort has been devoted to develop miRNA-targeting therapeutics in cancer. MicroRNA-7 (miR-7) has been characterized as a potential tumor suppressor and regulates diverse fundamental biological processes of cancer cells including initiation, proliferation, migration, invasion, survival and death by targeting a number of oncogenic signaling pathways.

AREAS COVERED

This review examines evidence of the biological responses of miR-7 in cancer, with an emphasis on its regulation of the vital oncogenic signaling pathways. It also discusses the rationale, strategies and challenges of miR-7 as a potential therapeutic target for cancer.

EXPERT OPINION

With the increasing understanding of molecular mechanisms of miR-7-mediated regulatory networks and the advancement of miRNA-based therapeutics, targeting miR-7 may be a potential and promising strategy for cancer therapy.

ACK1/TNK2 tyrosine kinase: molecular signaling and evolving role in cancers

Deregulated tyrosine kinase signaling alters cellular homeostasis to drive cancer progression. The emergence of a non-receptor tyrosine kinase, ACK1 as an oncogenic kinase, has uncovered novel mechanisms by which tyrosine kinase signaling promotes cancer progression. While early studies focused on ACK1 (also known as activated Cdc42-associated kinase 1 or TNK2) as a cytosolic effecter of activated transmembrane receptor tyrosine kinases (RTKs), wherein it shuttles between the cytosol and the nucleus to rapidly transduce extracellular signals from the RTKs to the intracellular effectors, recent data unfold a new aspect of its functionality as an epigenetic regulator. ACK1 interacts with the Estrogen Receptor (ER)/histone demethylase KDM3A (JHDM2a) complex, modifies KDM3A by tyrosine phosphorylation to regulate transcriptional outcome at HOXA1 locus to promote the growth of tamoxifen-resistant breast cancer. It is also well established that ACK1 regulates the activity of Androgen Receptor (AR) by tyrosine phosphorylation to fuel the growth of hormone-refractory prostate cancers. Further, recent explosion in genomic sequencing has revealed recurrent ACK1 gene amplification and somatic mutations in a variety of human malignancies, providing a molecular basis for its role in neoplastic transformation. In this review, we will discuss the various facets of ACK1 signaling, including its newly uncovered epigenetic regulator function, which enables cells to bypass the blockade to major survival pathways to promote resistance to standard cancer treatments. Not surprisingly, cancer cells appear to acquire an `addiction’ to ACK1 mediated survival, particularly under stress conditions, such as growth factor deprivation or genotoxic insults or hormone deprivation. With the accelerated development of potent and selective ACK1 inhibitors, targeted treatment for cancers harboring aberrant ACK1 activity may soon become a clinical reality.

PDGFR-β-activated ACK1-AKT signaling promotes glioma tumorigenesis

Aberrant PDGF-PDGFR signaling and its effects on downstream effectors have been implicated in glioma development. A crucial AKT regulator, ACK1 (TNK2) has been shown to be a downstream mediator of PDGF signaling; however, the exact underlying mechanisms in gliomas remain elusive. Here, we report that in glioma cells, PDGFR-β activation enhanced the interaction between ACK1 and AKT, resulting in AKT activation. PDGF treatment consistently promoted the formation of complexes containing PDGFR-β and ACK1. Mutational analysis suggested that Y635 of ACK1 is a PDGFR-β phosphorylation site and that the ACK1 Y635F mutant abrogated the sequential activation of AKT. Moreover, PDK1 interacted with ACK1 during PDGF stimulation, which is required for the binding of ACK1 to PDGFR-β. Further mutational analysis showed that T325 of ACK1 was crucial for the ACK1 and PDK1 interaction. ACK1 Y635F or T325A mutants abolished PDGFR-β-induced AKT activation, the subsequent nuclear translocation of β-catenin and the expression of cyclin D1. Glioma cell cycle progression, proliferation and tumorigenesis were accordingly blocked by ACK1 Y635F or T325A. In glioblastoma multiforme samples from 51 patients, increased ACK1 tyrosine phosphorylation correlated with upregulated PDGFR-β activity and AKT activation. Taken together, our data demonstrate that ACK1 plays a pivotal role in PDGF-PDGFR-induced AKT signaling in glioma tumorigenesis. This knowledge contributes to our understanding of glioma progression and may facilitate the identification of novel therapeutic targets for future glioma treatment.

Overexpression of activated Cdc42-associated kinase1 (Ack1) predicts tumor recurrence and poor survival in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers in China. Recent research suggested that activated Cdc42-associated kinase 1 (Ack1) played an important role in facilitating tumorigenesis, tumor invasion and metastasis. However, the role of Ack1 in HCC is not clear. Herein, the expression level of Ack1 mRNA in 30 fresh HCC specimens (carcinoma, peri-carcinoma and distal-carcinoma tissues) was detected by reverse transcription-polymerase chain reaction (RT-PCR), while the expression of Ack1 protein in 18 fresh HCC specimens (carcinoma, peri-carcinoma and distal-carcinoma tissues) was analyzed by Western blotting. Immunohistochemical (IHC) staining was also employed to assess both the expression level and distribution of Ack1 protein in HCC tissues collected from 173 lesions, so as to study the correlations between Ack1 protein expression and other HCC-related clinicopathologic parameters. The results showed that both Ack1 mRNA and protein were significantly over-expressed in HCC tissues than that of either peri-carcinoma or distal-carcinoma tissues (P < 0.001, P = 0.012, respectively), while there was no significant difference between peri-carcinoma and distal-carcinoma tissues. Furthermore, the results of IHC indicated that the rates of Ack1 expressions in the patients with capsular invasion, hepatic vessel involvement and recurrence were higher than without above three conditions (P = 0.037, P = 0.036, P = 0.019, respectively), whereas the patients with overexpression of Ack1 protein had low survival rate (P = 0.007). Ack1 expression, tumor size and recurrence were independently related to survival (P = 0.014, P = 0.018, P < 0.001, respectively). Thus, the level of Ack1 is associated with tumor invasion potential, and the expression of Ack1 plays an important role as predictor of recurrence and poor outcome in HCC patients.

ACK1 tyrosine kinase interacts with histone demethylase KDM3A to regulate the mammary tumor oncogene HOXA1

Hormone therapy with the selective estrogen-receptor modulator tamoxifen provides a temporary relief for patients with estrogen receptor α (ER)-positive breast cancers. However, a subset of patients exhibiting overexpression of the HER2 receptor tyrosine kinase displays intrinsic resistance to tamoxifen therapy. Therefore, elucidating the mechanisms promoting the estrogen (E2)-independent ER-regulated gene transcription in tamoxifen-resistant breast tumors is essential to identify new therapeutic avenues to overcome drug resistance and ameliorate poor prognosis. The non-receptor tyrosine kinase, ACK1 (also known as TNK2), has emerged as a major integrator of signaling from various receptor tyrosine kinases including HER2. We have uncovered that heregulin-mediated ACK1 activation promoted ER activity in the presence of tamoxifen, which was significantly down-regulated upon ACK1 knockdown or inhibition of ACK1 by small molecule inhibitors, AIM-100 or Dasatinib. We report that ACK1 phosphorylates the ER co-activator, KDM3A, a H3K9 demethylase, at an evolutionary conserved tyrosine 1114 site in a heregulin-dependent manner, even in the presence of tamoxifen. Consistent with this finding, ACK1 activation resulted in a significant decrease in the deposition of dimethyl H3K9 epigenetic marks. Conversely, inhibition of ACK1 by AIM-100 or Dasatinib restored dimethyl H3K9 methylation marks and caused transcriptional suppression of the ER-regulated gene HOXA1. Thus, by its ability to regulate the epigenetic activity of an ER co-activator KDM3A, ACK1 modulates HOXA1 expression in the absence of E2, conferring tamoxifen resistance. These data reveal a novel therapeutic option, suppression of ACK1 signaling by AIM-100 or Dasatinib, to mitigate HOXA1 up-regulation in breast cancer patients displaying tamoxifen resistance.

Androgen receptor activation in castration-recurrent prostate cancer: the role of Src-family and Ack1 tyrosine kinases

There is growing appreciation that castration-recurrent prostate cancer (CR-CaP) is driven by the continued expression of androgen receptor (AR). AR activation in CR-CaP through various mechanisms, including AR overexpression, expression of AR splice variants or mutants, increased expression of co-regulator proteins, and by post-translational modification, allows for the induction of AR-regulated genes in response to very low levels of tissue-expressed, so-called intracrine androgens, resulting in pathways that mediate CaP proliferation, anti-apoptosis and oncogenic aggressiveness. The current review focuses on the role played by Src-family (SFK) and Ack1 non-receptor tyrosine kinases in activating AR through direct phosphorylation, respectively, on tyrosines 534 or 267, and how these modifications facilitate progression to CR-CaP. The fact that SFK and Ack1 are central mediators for multiple growth factor receptor signaling pathways that become activated in CR-CaP, especially in the context of metastatic growth in the bone, has contributed to recent therapeutic trials using SFK/Ack1 inhibitors in monotherapy or in combination with antagonists of the AR activation axis.