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

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.

Phosphorylation of Ack1 by the Receptor Tyrosine Kinase Mer

Ack1 is a nonreceptor tyrosine kinase that is associated with cellular proliferation and survival. The receptor tyrosine kinase Mer, a member of the TAM family of receptors, has previously been reported to be an upstream activator of Ack1 kinase. The mechanism linking the two kinases, however, has not been investigated. We confirmed that Ack1 and Mer interact by co-immunoprecipitation experiments and found that Mer expression led to increased Ack1 activity. The effect on Ack1 was dependent on the kinase activity of Mer, whereas mutation of the Mer C-terminal tyrosines Y867 and Y924 did not significantly decrease the ability of Mer to activate Ack1. Ack1 possesses a Mig6 Homology Region (MHR) that contains adjacent regulatory tyrosines (Y859 and Y860). Using synthetic peptides, we showed that Mer preferentially binds and phosphorylates the MHR sequence containing phosphorylated pY860, as compared to the pY859 sequence. This suggested the possibility of sequential phosphorylation within the MHR of Ack1, as has been observed previously for other kinases. In cells co-expressing Mer and Ack1 MHR mutants, the Y859F mutant had higher activity than the Y860F mutant, consistent with this model. The interaction between Mer and Ack1 could play a role in immune cell signaling in normal physiology and could also contribute to the hyperactivation of Ack1 in prostate cancer and other tumors.

Design, Synthesis, and Evaluation of (R)-8-((Tetrahydrofuran-2-yl)methyl)pyrido[2,3-d]pyrimidin-7-ones as Novel Selective ACK1 Inhibitors to Combat Acquired Resistance to the Third-Generation EGFR Inhibitor

Activated Cdc42-associated kinase 1 (ACK1) alterations have been considered to mediate bypass acquired resistance to the third-generation EGFR inhibitors (ASK120067 and osimertinib) in NSCLC. Despite many efforts to develop ACK1 small molecule inhibitors, no selective inhibitors have entered clinical trials. We used structure-based drug design to obtain a series of (R)-8-((tetrahydrofuran-2-yl)methyl)pyrido [2,3-d]pyrimidin-7-ones as novel selective ACK1 inhibitors. One of the representative compounds, 10zi, potently inhibited ACK1 kinase with an IC₅₀ of 2.1 nM, while sparing SRC kinase (IC₅₀ = 218.7 nM). Further, 10zi displayed good kinome selectivity in a profiling of 468 kinases. In the ASK120067-resistant lung cancer cell line (67R), 10zi dose-dependently inhibited the phosphorylation of ACK1 and downstream AKT pathway and showed a strong synergistic anti-tumor effect in combination with ASK120067 in vitro. Additionally, 10zi also exhibited reasonable PK profiles with an oral bioavailability of 19.8% at the dose of 10 mg/kg, which provided a promising lead for further development of new anticancer drugs.

Domain Architecture of the Nonreceptor Tyrosine Kinase Ack1

The nonreceptor tyrosine kinase (NRTK) Ack1 comprises a distinct arrangement of non-catalytic modules. Its SH3 domain has a C-terminal to the kinase domain (SH1), in contrast to the typical SH3-SH2-SH1 layout in NRTKs. The Ack1 is the only protein that shares a region of high homology to the tumor suppressor protein Mig6, a modulator of EGFR. The vertebrate Acks make up the only tyrosine kinase (TK) family known to carry a UBA domain. The GTPase binding and SAM domains are also uncommon in the NRTKs. In addition to being a downstream effector of receptor tyrosine kinases (RTKs) and integrins, Ack1 can act as an epigenetic regulator, modulate the degradation of the epidermal growth factor receptor (EGFR), confer drug resistance, and mediate the progression of hormone-sensitive tumors. In this review, we discuss the domain architecture of Ack1 in relation to other protein kinases that possess such defined regulatory domains.

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.

Protein Lysine Methyltransferase SMYD2: A Promising Small Molecule Target for Cancer Therapy

In epigenetic research, the abnormality of protein methylation modification is closely related to the occurrence and development of tumors, which stimulates the interest of researchers in protein methyltransferase research and the efforts to develop corresponding specific small molecule inhibitors. Currently, the protein lysine methyltransferase SMYD2 has been identified as a promising new small molecule target for cancer therapy. But its biological functions have not been fully studied and relatively few inhibitors have been reported, thus this field needs to be further explored. This perspective provides a comprehensive and systematic review of the available resources in this field, including its research status, biological structure, related substrates and methylation mechanisms, and research status of inhibitors. In addition, this perspective elaborates in detail the current challenges in this field, our insights into what needs to be done next, rational drug design of novel SMYD2 inhibitors, and foreseeable development directions in the future.

Targeting EGFR in melanoma - The sea of possibilities to overcome drug resistance

Melanoma is considered one of the most aggressive skin cancers. It spreads and metastasizes quickly and is intrinsically resistant to most conventional chemotherapeutics, thereby presenting a challenge to researchers and clinicians searching for effective therapeutic strategies to treat patients with melanoma. The use of inhibitors of mutated serine/threonine-protein kinase B-RAF (BRAF), e.g., vemurafenib and dabrafenib, has revolutionized melanoma chemotherapy. Unfortunately, the response to these drugs lasts a limited time due to the development of acquired resistance. One of the proteins responsible for this process is epidermal growth factor receptor (EGFR). In this review, we summarize the role of EGFR signaling in the multidrug resistance of melanomas and discuss possible applications of EGFR inhibitors to overcome the development of drug resistance in melanoma cells during therapy.

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.

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.