Microtubule-affinity regulating kinase 4: A potential drug target for cancer therapy

Mechanistic insights into the inhibition of microtubule affinity-regulating kinase 4 by Syringic acid: A computational and experimental study

Microtubule affinity regulating kinase 4 (MARK4) is a vital protein kinase that serves as a dual target in cancer and neurodegenerative diseases. It is implicated in the development of tauopathies and also linked to the pathogenesis of several cancer types, implying its importance. Syringic acid is a naturally occurring phenolic molecule that has shown significant efficacies in cancer and neurodegenerative diseases by modulating several key pathways. Thus, the present study aims to investigate the inhibitory potential of syringic acid against the protein kinase MARK4, employing a combination of experimental and computational approaches. Molecular docking revealed the binding of syringic acid in the MARK4's binding pocket, interacting with key functional residues of the protein kinase. Molecular dynamic simulation (MD) studies demonstrated the conformational dynamics and structural stability of MARK4 upon the binding of syringic acid. In silico findings were further complemented by experimental assays. Enzyme inhibition assay showed that syringic acid effectively inhibits MARK4 with an IC50 value of 4.32 μM. Fluorescence binding assays revealed a strong binding affinity (K = 2.8 × 106 M-1). The findings of our study establish syringic acid as a potent MARK4 inhibitor, providing a perfect platform for its use in tackling MARK4-associated diseases.

Experimental and theoretical studies on structural changes in the microtubule affinity-regulating kinase 4 (MARK4) protein induced by N-hetarenes: a new class of therapeutic candidates for Alzheimer's disease

Introduction

Alzheimer's disease (AD) is a neurodegenerative disorder that progressively affects the cognitive function and memory of the affected person. Unfortunately, only a handful of effective prevention or treatment options are available today. Microtubule affinity-regulating kinase 4 (MARK4) is a serine/threonine protein that plays a critical role in regulating microtubule dynamics and facilitating cell division. The dysregulated expression of MARK4 has been associated with a range of diseases, including AD.

Methods

In this study, we synthesized a series of N-hetarenes via Pd(0)-catalyzed Suzuki-Miyaura cross coupling reaction. All compounds were characterized using multi-spectroscopic techniques and evaluated for their activity against the MARK4 enzyme through ATPase inhibition assays. The experimental data was further supported by computational and quantum chemical calculations. We also computed the drug-likeness, bioavailability, and toxicity (ADME/T) profiles of the compounds.

Results

Six new 4-(6-(arylpyrimidin-4-yl)piperazine-1-carboximidamides 5-10 were prepared in good yields. ATPase inhibition assay conducted on these compounds demonstrated IC50 values in micromolar range (5.35 ± 0.22 to 16.53 ± 1.71 μM). Among the tested compounds, 4-(6-(p-tolyl)pyrimidin-4-yl)piperazine-1-carboximidamide (5; IC50 = 5.35 ± 0.22 μM) and 4-(6-(benzo[b]thiophen-2-yl)pyrimidin-4-yl)piperazine-1-carboximidamide (9; IC50 = 6.68 ± 0.80 μM) showed the best activity. The binding constant (K), as determined by the fluorescence quenching assay was estimated to be 1.5 ± 0.51 × 105 M-1 for 5 and 1.14 ± 0.26 × 105 M-1 for 9. The results of molecular docking and MD simulation studies against MARK4 (PDB: 5ES1) indicated that compounds were able to bind the ATP binding pocket of the MARK4, leading to its stabilization. Additionally, ADME/T analysis revealed a high degree of drug-likeness of the compounds.

Conclusion

We demonstrated that 4-(6-(arylpyrimidin-4-yl)piperazine-1-carboximidamides) are a promising class of N-hetarenes for developing next-generation anti-AD drugs. The reported class of compounds inhibited MARK4 activity in-vitro at micromolar concentration by targeting the ATP-binding pocket. These findings provide valuable insights for future drug design.

Understanding of Alzheimer's disease pathophysiology for therapeutic implications of natural products as neuroprotective agents

Alzheimer's disease (AD) is a leading cause of dementia, affecting more than 24.3 million people worldwide in 2024. Sporadic AD (SAD) is more common and occurs in the geriatric population, while familial AD (FAD) is rare and appears before the age of 65 years. Due to progressive cholinergic neuronal loss and modulation in the PKC/MAPK pathway, β-secretase gets upregulated, leading to Aβ aggregation, which further activates tau kinases that form neurofibrillary tangles (NFT). Simultaneously, antioxidant enzymes are also upregulated, increasing oxidative stress (OS) and reactive species by impairing mitochondrial function, leading to DNA damage and cell death. This review discusses the classifications and components of several natural products (NPs) that target these signaling pathways for AD treatment. NPs, including alkaloids, polyphenols, flavonoids, polysaccharides, steroids, fatty acids, tannins, and polypeptides derived from plants, microbes, marine animals, venoms, insects, and mushrooms, are explored in detail. A synergistic combination of plant metabolites, together with prebiotics and probiotics has been shown to decrease Aβ aggregates by increasing the production of bioactive compounds. Toxins derived from venomous organisms have demonstrated effectiveness in modulating signaling pathways and reducing OS. Marine metabolites have also shown neuroprotective and anti-inflammatory properties. The cholera toxin B subunit and an Aβ15 fragment have been combined to create a possible oral AD vaccine, that showed enhancement of cognitive function in mice. Insect tea is also a reliable source of antioxidants. A functional edible mushroom snack bar showed an increment in cognitive markers. Future directions and therapeutic approaches for the treatment of AD can be improved by focusing more on NPs derived from these sources.

Apigenin-mediated MARK4 inhibition: a novel approach in advancing Alzheimer's disease therapeutics

Apigenin, a dietary flavonoid with notable anti-cancer properties, has emerged as a promising candidate for the treatment of neurodegenerative disorders, particularly Alzheimer's disease (AD). While extensively studied for its ability to modulate key molecular pathways in cancers, apigenin also exerts neuroprotective effects by reducing neuroinflammation, protecting neurons from oxidative stress, and enhancing neuronal survival and synaptic plasticity. This dual functionality makes apigenin an intriguing therapeutic option for diseases like AD, where kinase dysregulation plays a central role. In this study, we focus on Microtubule Affinity-Regulating Kinase 4 (MARK4), a key enzyme implicated in tauopathies associated with AD, as well as in cancer progression. Through in silico analysis, we explore the interaction between apigenin and MARK4, revealing significant structural changes within the kinase domain upon ligand binding. These computational findings were confirmed via experimental assays using purified recombinant MARK4, where apigenin demonstrated potent inhibition with an IC50 value of 2.39 µM. Fluorescence binding assays further confirmed a strong binding affinity (Ka = 108 M-1), indicating that apigenin efficiently occupies the MARK4 active site, thereby suppressing its enzymatic activity. These results position apigenin as a potent inhibitor of MARK4, offering a dual therapeutic advantage-both as an anti-cancer agent and as a neuroprotective compound for the potential treatment of AD. This study opens new avenues for the development of apigenin-based therapeutics targeting kinase dysregulation in cancer and neurodegeneration.

Function of a complex of p-Y42 RhoA GTPase and pyruvate kinase M2 in EGF signaling pathway in glioma cells

Epidermal growth factor (EGF) is known to be a critical stimulant for inducing the proliferation of glioma cancer cells. In our study, we observed that GST-RhoA binds to pyruvate kinase M2 (PKM2) in vitro. While EGF reduced the levels of RhoA protein, it significantly increased p-Y42 RhoA, as well as PKM1 and PKM2 in LN18 glioma cell line. We determined that RhoA undergoes degradation through ubiquitination involving SCF1 and Smurf1. Interestingly, we observed that p-Y42 RhoA binds to PKM2, while the dephosphomimetic form, RhoA Y42F, did not. Additionally, our observation revealed that PKM2 stabilized both RhoA and p-Y42 RhoA. Importantly, RhoA, p-Y42 RhoA, and PKM2, but not RhoA-GTP, were localized in the nucleus upon EGF stimulation. Knockdown of RhoA with siRNA resulted in the reduced levels of phosphoglycerate kinase1 (PGK1) and microtubule affinity-regulating kinase 4 (MARK). Furthermore, we found that the promoter of PGK1 was associated with β-catenin and YAP. Notably, p-Y42 RhoA and PKM2 co-immunoprecipitated with β-catenin and YAP. Based on these findings, we proposed a novel mechanism by which p-Y42 RhoA and PKM2, in conjunction with β-catenin and YAP, regulate PGK1 expression, contributing to the progression of glioma upon EGF.

Rosmarinic Acid: A Potential Therapeutic Agent in Gastrointestinal Cancer Management-A Review

Gastrointestinal cancers are still the leading cause of death worldwide. This is related, among other things, to the non-specific symptoms, especially in the initial stages, and also to the limited possibilities for treatment. Therefore, research is still being conducted to improve the detection of this type of cancer and increase the effectiveness of therapy. The potential application of natural compounds in cancer management deserves special attention. In the group of such products, there are polyphenolic compounds that reveal, e.g., anti-oxidative, anti-carcinogenic, anti-inflammatory, anti-diabetic, and neuroprotective properties. One of these polyphenols is rosmarinic acid, commonly found in plants such as the Boraginaceae and Nepetoideae subfamilies of the Lamiaceae (mint) family. A number of studies have considered the positive effects of rosmarinic acid in the treatment of many cancers, including gastrointestinal ones such as oral, stomach, pancreas, colon, and liver cancers. The main aim of this paper was to summarize the mechanisms of action of rosmarinic acid in gastrointestinal cancers.

Design, synthesis, molecular docking and anti-proliferative activity of novel phenothiazine containing imidazo[1,2-a]pyridine derivatives against MARK4 protein

A series of novel phenothiazine-containing imidazo[1,2-a]pyridine derivatives were designed and synthesized under metal-free conditions in excellent yield. These derivatives were effectively transformed further into N-alkyl, sulfoxide, and sulfone derivatives. Derivatives were deployed against human microtubule affinity regulating kinase (MARK4), some molecules play crucial roles in cell-cycle progression such as G1/S transition and regulator of microtubule dynamics. Hence, molecules have shown excellent MARK4 inhibitory potential. Molecules with excellent IC50 values were selected for further studies such as ligand interactions using fluorescence quenching experiments for the binding constant. The highest binding constant was calculated as K = 0.79 × 105 and K = 0.1 × 107 for compounds 6a and 6h, respectively. Molecular docking, cell cytotoxicity, mitochondrial reactive oxygen species measurement and oxidative DNA damage were also studied to understand the mechanism of action of the molecules on cancer cells. It was found that the designed and synthesized compounds played anti-cancer roles by binding and inhibiting MARK4 protein.

TUBB, a robust biomarker with satisfying abilities in diagnosis, prognosis, and immune regulation via a comprehensive pan-cancer analysis

Purpose

TUBB can encode a beta-tubulin protein. At present, the role of TUBB has not been ascertained in cancers. Hence, the importance of further systematic pan-cancer analyses is stressed to explore its value in the diagnosis, prognosis, and immune function of cancers.

Methods

By collecting and handling integrative data from the TCGA, Firehose, UCSC Xena, cBioPortal, GEO, CPTAC, TIMER2.0, TISCH, CellMiner, GDSC, and CTRP databases, we explored the potential diagnostic and prognostic roles of TUBB in pan-cancers from multiple angles. Moreover, the GSEA analysis was conducted to excavate the biological functions of TUBB in pan-cancers. In addition, survival profiles were described, and the differential expressions of TUBB in different molecular subtypes were discussed. Also, we utilized the cMAP function to search drugs or micro-molecules that have an impact on TUBB expressions.

Results

Based on the TCGA data, we found that TUBB was differentially expressed in a variety of tumors and showed an early-diagnostic value. Mutations, somatic copy number alterations, and DNA methylation would lead to its abnormal expression. TUBB expressions had relations with many clinical features. What's more, TUBB expressions were validated to be related to many metabolism-related, metastasis-related, and immune-related pathways. High TUBB expressions were proved to have a great impact on the prognosis of various types of cancers and would affect the sensitivity of some drugs. We also demonstrated that the expression of TUBB was significantly correlated to immunoregulator molecules and biomarkers of lymphocyte subpopulation infiltration.

Conclusion

TUBB and its regulatory genes were systemically analyzed in this study, showing that TUBB had satisfying performances in disease diagnosing and prognosis predicting of multiple cancers. It could remodel the tumor microenvironment and play an integral role in guiding cancer therapies and forecasting responses to chemotherapy.

Role of MARK2 in the nervous system and cancer

Microtubule-Affinity Regulating Kinase 2 (MARK2), a member of the serine/threonine protein kinase family, phosphorylates microtubule-associated proteins, playing a crucial role in cancer and neurodegenerative diseases. This kinase regulates multiple signaling pathways, including the WNT, PI3K/AKT/mTOR (PAM), and NF-κB pathways, potentially linking it to cancer and the nervous system. As a crucial regulator of the PI3K/AKT/mTOR pathway, the loss of MARK2 inhibits the growth and metastasis of cancer cells. MARK2 is involved in the excessive phosphorylation of tau, thus influencing neurodegeneration. Therefore, MARK2 emerges as a promising drug target for the treatment of cancer and neurodegenerative diseases. Despite its significance, the development of inhibitors for MARK2 remains limited. In this review, we aim to present detailed information on the structural features of MARK2 and its role in various signaling pathways associated with cancer and neurodegenerative diseases. Additionally, we further characterize the therapeutic potential of MARK2 in neurodegenerative diseases and cancer, and hope to facilitate basic research on MARK2 and the development of inhibitors targeting MARK2.

Recent Advances in Pyrazole-based Protein Kinase Inhibitors as Emerging Therapeutic Targets

BACKGROUND

Pyrazole-scaffold protein kinase inhibitors (PKIs) have emerged as promising therapeutic agents for the treatment of various diseases, such as cancer, inflammatory disorders, and neurological diseases. This review article provides an overview of the pharmacological properties of pyrazole-scaffold PKIs, including their mechanism of action, selectivity, potency, and toxicity. The article also summarizes the recent developments in the design and synthesis of pyrazole-scaffold PKIs, highlighting the structural features and modifications that contribute to their pharmacological activity. In addition, the article discusses the preclinical and clinical studies of pyrazole-scaffold PKIs, including their efficacy, safety, and pharmacokinetic properties.

METHODS

A comprehensive search has been conducted on several online patent databases, including the United States Patent and Trademark Office (USPTO), the European Patent Office (EPO), and the World Intellectual Property Organization (WIPO). The search was conducted using pyrazole as the keyword. The search was limited to patents filed between 2015 and 2022. Patents were included if they involved articles in the fields of protein kinase inhibitors, and included literature on some pyrazoles and their pharmacological activities.

RESULTS

Data were extracted from each included patent on the following variables: patent title, patent number, inventors, assignee, filing date, publication date, patent type, and field of invention. Data were extracted from each patent using a standardized form to ensure consistency and accuracy.

CONCLUSION

The design and pharmacological evaluation of organic compounds containing pyrazole structure as biologically active substances have been done, and the key structures from the pharmacological data obtained as protein kinase inhibitors have been addressed in detail. The review concludes with a discussion on the current challenges and future directions for the development of pyrazole-scaffold PKIs as therapeutic agents. Overall, this review article provides a comprehensive summary of the pharmacological properties of pyrazole-scaffold PKIs, which will be of interest to researchers and clinicians in the field of drug discovery and development.

Rosemary as a Potential Source of Natural Antioxidants and Anticancer Agents: A Molecular Docking Study

Rosmarinus officinalis L. compounds, especially its main polyphenolic compounds, carnosic acid (CA) and rosmarinic acid (RA), influence various facets of cancer biology, making them valuable assets in the ongoing fight against cancer. These two secondary metabolites exhibit formidable antioxidant properties that are a pivotal contributor against the development of cancer. Their antitumor effect has been related to diverse mechanisms. In the case of CA, it has the capacity to induce cell death of cancer cells through the rise in ROS levels within the cells, the inhibition of protein kinase AKT, the activation of autophagy-related genes (ATG) and the disrupt mitochondrial membrane potential. Regarding RA, its antitumor actions encompass apoptosis induction through caspase activation, the inhibition of cell proliferation by interrupting cell cycle progression and epigenetic regulation, antioxidative stress-induced DNA damage, and interference with angiogenesis to curtail tumor growth. To understand the molecular interaction between rosemary compounds (CA and RA) and a protein that is involved in cancer and inflammation, S100A8, we have performed a series of molecular docking analyses using the available three-dimensional structures (PDBID: 1IRJ, 1MR8, and 4GGF). The ligands showed different binding intensities in the active sites with the protein target molecules, except for CA with the 1MR8 protein.

A cell-penetrating peptide derived from SARS-CoV-2 protein Orf9b allosterically inhibits MARK4 activity and mitigates tau toxicity

Abnormal activation of microtubule affinity-regulating kinase 4 (MARK4) and its phosphorylation of the microtubule-associated protein tau are believed to play a role in the pathogenesis of Alzheimer's disease, and MARK4 inhibition can be a strategy to develop disease-modifying therapy. Here we report the development of a membrane-permeable peptide that inhibits MARK4 activity in an allosteric manner. The SARS-CoV-2-derived protein Orf9b inhibited MARK4-mediated tau phosphorylation in primary neurons and Drosophila. Orf9b inhibited MARK4 activity in an allosteric manner and did not inhibit the activity of MARK2, which is another MARK family member and is closely related to MARK4. Co-expression of Orf9b in the fly retina expressing human tau and MARK4 suppressed phosphorylation of tau at the microtubule-binding repeats and tau-induced neurodegeneration. We identified the minimal sequence of Orf9b required to suppress MARK4 activity and fused it to a cell-permeable sequence (TAT-Orf9b10-18_78-95). Extracellular supplementation of TAT-Orf9b10-18_78-95 inhibited MARK4 activity in primary neurons, and feeding TAT-Orf9b10-18_78-95 to a fly model of tauopathy lowered phospho-tau levels and suppressed neurodegeneration. These results suggest that TAT-Orf9b10-18_78-95 is a unique class of MARK4 inhibitor and can be used to modify tau toxicity.

Mechanistic insights into MARK4 inhibition by galantamine toward therapeutic targeting of Alzheimer's disease

Introduction: Hyperphosphorylation of tau is an important event in Alzheimer's disease (AD) pathogenesis, leading to the generation of "neurofibrillary tangles," a histopathological hallmark associated with the onset of AD and related tauopathies. Microtubule-affinity regulating kinase 4 (MARK4) is an evolutionarily conserved Ser-Thr (S/T) kinase that phosphorylates tau and microtubule-associated proteins, thus playing a critical role in AD pathology. The uncontrolled neuronal migration is attributed to overexpressed MARK4, leading to disruption in microtubule dynamics. Inhibiting MARK4 is an attractive strategy in AD therapeutics. Methods: Molecular docking was performed to see the interactions between MARK4 and galantamine (GLT). Furthermore, 250 ns molecular dynamic studies were performed to investigate the stability and conformational dynamics of the MARK4-GLT complex. We performed fluorescence binding and isothermal titration calorimetry studies to measure the binding affinity between GLT and MARK4. Finally, an enzyme inhibition assay was performed to measure the MARK4 activity in the presence and absence of GLT. Results: We showed that GLT, an acetylcholinesterase inhibitor, binds to the active site cavity of MARK4 with an appreciable binding affinity. Molecular dynamic simulation for 250 ns demonstrated the stability and conformational dynamics of the MARK4-GLT complex. Fluorescence binding and isothermal titration calorimetry studies suggested a strong binding affinity. We further show that GLT inhibits the kinase activity of MARK4 significantly (IC50 = 5.87 µM). Conclusion: These results suggest that GLT is a potential inhibitor of MARK4 and could be a promising therapeutic target for AD. GLT's inhibition of MARK4 provides newer insights into the mechanism of GLT's action, which is already used to improve cognition in AD patients.

Therapeutic targeting of microtubule affinity-regulating kinase 4 in cancer and neurodegenerative diseases

Microtubule affinity-regulating kinase 4 (MARK4) is a member of the Ser/Thr protein kinase family, phosphorylates the microtubule-connected proteins and plays a vital role in causing cancers and neurodegenerative diseases. This kinase modulates multiple signaling pathways, including mammalian target of rapamycin, nuclear factor-κB, and Hippo-signaling, presumably responsible for cancer and Alzheimer's. MARK4 acts as a negative controller of the Hippo-kinase cassette for promoting YAP/TAZ action, and the loss of MARK4 detains the tumorigenic properties of cancer cells. MARK4 is involved in tau hyperphosphorylation that consequently affects neurodegeneration. MARK4 is a promising drug target for cancer, diabetes, and Alzheimer's. Developing the potent and selective inhibitors of MAKR4 are promising in the therapeutic management of associated diseases. Despite its great significance, a few reviews are available to discuss its structure, function and clinical significance. In the current review, we aimed to provide detailed information on the structural features of MARK4 targeted in drug development and its role in various signaling pathways related to cancer and neurodegenerative diseases. We further described the therapeutic potential of MARK4 inhibitors in preventing numerous diseases. Finally, the updated information on MARK4 will be helpful in the further development of effective therapeutic molecules.

Insight into the Biological Roles and Mechanisms of Phytochemicals in Different Types of Cancer: Targeting Cancer Therapeutics

Cancer is a hard-to-treat disease with a high reoccurrence rate that affects health and lives globally. The condition has a high occurrence rate and is the second leading cause of mortality after cardiovascular disorders. Increased research and more profound knowledge of the mechanisms contributing to the disease’s onset and progression have led to drug discovery and development. Various drugs are on the market against cancer; however, the drugs face challenges of chemoresistance. The other major problem is the side effects of these drugs. Therefore, using complementary and additional medicines from natural sources is the best strategy to overcome these issues. The naturally occurring phytochemicals are a vast source of novel drugs against various ailments. The modes of action by which phytochemicals show their anti-cancer effects can be the induction of apoptosis, the onset of cell cycle arrest, kinase inhibition, and the blocking of carcinogens. This review aims to describe different phytochemicals, their classification, the role of phytochemicals as anti-cancer agents, the mode of action of phytochemicals, and their role in various types of cancer.

Inhibition of microtubule affinity regulating kinase 4 by an acetylcholinesterase inhibitor, Huperzine A: Computational and experimental approaches

Microtubule affinity regulating kinase 4 (MARK4), 752 amino acids long, belonging to the AMPK superfamily, plays a vital role in regulating microtubules due to its potential to phosphorylate microtubule-associated proteins (MAP's) and thus, MARK4 plays a key role in Alzheimer's disease (AD) pathology. MARK4 is a druggable target for cancer, neurodegenerative diseases, and metabolic disorders. In this study, we have evaluated the MARK4 inhibitory potential of Huperzine A (HpA), an acetylcholinesterase inhibitor (AChEI), a potential AD drug. Molecular docking revealed the key residues governing the MARK4-HpA complex formation. The structural stability and conformational dynamics of the MARK4-HpA complex was assessed by employing Molecular dynamics (MD) simulation. The results suggested that the binding of HpA with MARK4 leads to minimal structural alterations in the native conformation of MARK4, implying the stability of the MARK4-HpA complex. Isothermal titration calorimetry (ITC) studies deciphered that HpA binds to MARK4 spontaneously. Moreover, the kinase assay depicted significant inhibition of MARK by HpA (IC₅₀ = 4.91 μM), implying it to be a potent MARK4 inhibitor that can be implicated in the treatment of MARK4-directed diseases.