Zafirlukast inhibits the growth of lung adenocarcinoma via inhibiting TMEM16A channel activity

Development and therapeutic implications of small molecular inhibitors that target calcium-related channels in tumor treatment

Calcium ion dysregulation exerts profound effects on various physiological activities such as tumor proliferation, migration, and drug resistance. Calcium-related channels play a regulatory role in maintaining calcium ion homeostasis, with most channels being highly expressed in tumor cells. Additionally, these channels serve as potential drug targets for the development of antitumor medications. In this review, we first discuss the current research status of these pathways, examining how they modulate various tumor functions such as epithelial-mesenchymal transition (EMT), metabolism, and drug resistance. Simultaneously, we summarize the recent progress in the study of novel small-molecule drugs over the past 5 years and their current status.

Liensinine, a Novel and Food-Derived Compound, Exerts Potent Antihepatoma Efficacy via Inhibiting the Kv10.1 Channel

Plant metabolites from natural product extracts offer unique advantages against carcinogenesis in the development of drugs. The target-based virtual screening from food-derived compounds represents a promising approach for tumor therapy. In this study, we performed virtual screening to target the presumed inhibitor-binding pocket and identified a highly potent Kv10.1 inhibitor, liensinine (Lien), which can inhibit the channel in a dose-dependent way with an IC50 of 0.24 ± 0.07 μM. Combining molecular dynamics simulations with mutagenesis experiments, our data show that Lien interacts with Kv10.1 by binding with Y539, T543, D551, E553, and H601 in the C-linker domain of Kv10.1. In addition, the interaction of sequence alignment and 3D structural modeling revealed differences between the C-linker domain of the Kv10.1 channel and the Kv11.1 channel. Furthermore, antitumor experiments revealed that Lien suppresses the proliferation and migration of HCC both in vitro and in vivo. In summary, the food-derived compound, Lien, may serve as a lead compound for antihepatoma therapeutic drugs targeting Kv10.1.

AIM2 fosters lung adenocarcinoma immune escape by modulating PD-L1 expression in tumor-associated macrophages via JAK/STAT3

This work was devised to discuss the effect of AIM2 on the immunosuppression of LUAD tumors, as well as its molecular mechanism. An allograft mouse model was built. Mouse macrophages were isolated and collected. The infiltration level of Mø and expression of M1 Mø, M2 Mø markers, and PD-L1 were assayed by IHC and flow cytometry. Expression levels of M1 Mø and M2 Mø marker genes and PD-L1 were detected by qPCR. The expression of proteins linked with JAK/STAT3 was tested by western blot. CD8+T cells and NK cells were activated in vitro and co-cultured with mouse macrophages, and their cytotoxicity was detected by LDH method. The proportion of CD206+PD-L1+ cells and the activation and proliferation of CD8+T cells were assayed by flow cytometry. Multicolor immunofluorescence was utilized to assay the co-localization of proteins. AIM2 demonstrated a high expression in LUAD, exhibiting a conspicuous positive correlation with the expression of the M2 Mø markers as well as PD-L1. Expression of M1 markers was upregulated after knockdown of AIM2, while M2 markers expression and PD-L1 were downregulated, and the colocalization of proteins linked with PD-L1 and M2 Mø was decreased. The infiltration and cytotoxicity of CD8+T cells and NK cells increased after silencing AIM2. After the knockdown of AIM2, which was enriched in the JAK/STAT3 pathway, the phosphorylation levels of JAK1, JAK2, and STAT3 were reduced, the immune infiltration level of CD8+T cells increased, and the co-localization level of PD-L1 and PD-1 dropped. The activity and proliferation level of CD8+T cells were increased with the reduced PD-1 expression. AIM2 fosters M2 Mø polarization and PD-L1 expression via the JAK/STAT3 pathway. Moreover, AIM2 promotes the immune escape of LUAD via the PD-1/PD-L1 axis. Our work may blaze a trail for the clinical treatment of LUAD.

Identification of potential molecular targets for the treatment of cluster 1 human pheochromocytoma and paraganglioma via comprehensive proteomic characterization

BACKGROUND

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors. New drug targets and proteins that would assist sensitive PPGL imagining could improve therapy and quality of life of patients with PPGL, namely those with recurrent or metastatic disease. Using a combined proteomic strategy, we looked for such clinically relevant targets among integral membrane proteins (IMPs) upregulated on the surface of tumor cells and non-membrane druggable enzymes in PPGL.

METHODS

We conducted a detailed proteomic analysis of 22 well-characterized human PPGL samples and normal chromaffin tissue from adrenal medulla. A standard quantitative proteomic analysis of tumor lysate, which provides information largely on non-membrane proteins, was accompanied by specific membrane proteome-aimed methods, namely glycopeptide enrichment using lectin-affinity, glycopeptide capture by hydrazide chemistry, and enrichment of membrane-embedded hydrophobic transmembrane segments.

RESULTS

The study identified 67 cell surface integral membrane proteins strongly upregulated in PPGL compared to control chromaffin tissue. We prioritized the proteins based on their already documented direct role in cancer cell growth or progression. Increased expression of the seven most promising drug targets (CD146, CD171, ANO1, CD39, ATP8A1, ACE and SLC7A1) were confirmed using specific antibodies. Our experimental strategy also provided expression data for soluble proteins. Among the druggable non-membrane enzymes upregulated in PPGL, we identified three potential drug targets (SHMT2, ARG2 and autotaxin) and verified their upregulated expression.

CONCLUSIONS

Application of a combined proteomic strategy recently presented as "Pitchfork" enabled quantitative analysis of both, membrane and non-membrane proteome, and resulted in identification of 10 potential drug targets in human PPGL. Seven membrane proteins localized on the cell surface and three non-membrane druggable enzymes proteins were identified and verified as significantly upregulated in PPGL. All the proteins have been previously shown to be upregulated in several human cancers, and play direct role in cancer progression. Marked upregulation of these proteins along with their localization and established direct roles in tumor progression make these molecules promising candidates as drug targets or proteins for sensitive PPGL imaging.

Recent Advances in Computer-Aided Structure-Based Drug Design on Ion Channels

Ion channels play important roles in fundamental biological processes, such as electric signaling in cells, muscle contraction, hormone secretion, and regulation of the immune response. Targeting ion channels with drugs represents a treatment option for neurological and cardiovascular diseases, muscular degradation disorders, and pathologies related to disturbed pain sensation. While there are more than 300 different ion channels in the human organism, drugs have been developed only for some of them and currently available drugs lack selectivity. Computational approaches are an indispensable tool for drug discovery and can speed up, especially, the early development stages of lead identification and optimization. The number of molecular structures of ion channels has considerably increased over the last ten years, providing new opportunities for structure-based drug development. This review summarizes important knowledge about ion channel classification, structure, mechanisms, and pathology with the main focus on recent developments in the field of computer-aided, structure-based drug design on ion channels. We highlight studies that link structural data with modeling and chemoinformatic approaches for the identification and characterization of new molecules targeting ion channels. These approaches hold great potential to advance research on ion channel drugs in the future.

Ion Channels as Potential Tools for the Diagnosis, Prognosis, and Treatment of HPV-Associated Cancers

The human papilloma virus (HPV) group comprises approximately 200 genetic types that have a special affinity for epithelial tissues and can vary from producing benign symptoms to developing into complicated pathologies, such as cancer. The HPV replicative cycle affects various cellular and molecular processes, including DNA insertions and methylation and relevant pathways related to pRb and p53, as well as ion channel expression or function. Ion channels are responsible for the flow of ions across cell membranes and play very important roles in human physiology, including the regulation of ion homeostasis, electrical excitability, and cell signaling. However, when ion channel function or expression is altered, the channels can trigger a wide range of channelopathies, including cancer. In consequence, the up- or down-regulation of ion channels in cancer makes them attractive molecular markers for the diagnosis, prognosis, and treatment of the disease. Interestingly, the activity or expression of several ion channels is dysregulated in HPV-associated cancers. Here, we review the status of ion channels and their regulation in HPV-associated cancers and discuss the potential molecular mechanisms involved. Understanding the dynamics of ion channels in these cancers should help to improve early diagnosis, prognosis, and treatment in the benefit of HPV-associated cancer patients.

Identification of a druggable pocket of the calcium-activated chloride channel TMEM16A in its open state

The calcium-activated chloride channel TMEM16A is a potential drug target to treat hypertension, secretory diarrhea, and several cancers. However, all reported TMEM16A structures are either closed or desensitized, and direct inhibition of the open state by drug molecules lacks a reliable structural basis. Therefore, revealing the druggable pocket of TMEM16A exposed in the open state is important for understanding protein-ligand interactions and facilitating rational drug design. Here, we reconstructed the calcium-activated open conformation of TMEM16A using an enhanced sampling algorithm and segmental modeling. Furthermore, we identified an open state druggable pocket and screened a potent TMEM16A inhibitor, etoposide, which is a derivative of a traditional herbal monomer. Molecular simulations and site-directed mutagenesis showed that etoposide binds to the open state of TMEM16A, thereby blocking the ion conductance pore of the channel. Finally, we demonstrated that etoposide can target TMEM16A to inhibit the proliferation of prostate cancer PC-3 cells. Together, these findings provide a deep understanding of the TMEM16A open state at an atomic level and identify pockets for the design of novel inhibitors with broad applications in chloride channel biology, biophysics, and medicinal chemistry.

Drug repurposing and molecular mechanisms of the antihypertensive drug candesartan as a TMEM16A channel inhibitor

TMEM16A, a Ca²⁺-activated chloride channel (CaCC), and its pharmacological inhibitors can inhibit the growth of lung adenocarcinoma cells. However,the poor efficacy, safety, and stability of TMEM16A inhibitors limit the development of these agents. Therefore, finding new therapeutic directions from already marketed drugs is a feasible strategy to obtain safe and effective therapeutic drugs. Here, we screened a library contain more than 2400 FDA, EMA, and NMPA-approved drugs through virtual screening. We identified a drug candidate, candesartan (CDST), which showed strong inhibitory effect on the TMEM16A in a concentration-dependent manner with an IC₅₀ of 24.40 ± 3.21 μM. In addition, CDST inhibited proliferation, migration and induced apoptosis of LA795 cells targeting TMEM16A, and significantly inhibited lung adenocarcinoma tumor growth in vivo. The molecular mechanism of CDST inhibiting TMEM16A channel indicated it bound to R515/R535/E623/E624 in the drug pocket, thereby blocked the pore. In conclusion, we identified a novel TMEM16A channel inhibitor, CDST, which exhibited excellent inhibitory activity against lung adenocarcinoma. Considering that CDST has been used in clinical treatment of hypertension, it may play an important role in the combined treatment of hypertension and lung adenocarcinoma as a multi-target drug in the future.

Searching for Novel Noncovalent Nuclear Export Inhibitors through a Drug Repurposing Approach

Chromosomal region maintenance protein 1 (CRM1) is a validated anticancer drug target, and its covalent inhibitor KPT-330 has been approved for marketing. However, the development of CRM1 inhibitors, especially the noncovalent ones, is still very limited. Drug repurposing is an effective strategy to develop drug leads for new targets. In this work, we virtually screened a library of marketed drugs and identified zafirlukast as a new CRM1 inhibitor. Biochemical and structural analysis revealed that zafirlukast was a noncovalent CRM1 inhibitor that bound to four subpockets in the nuclear-export-signal (NES) groove. Methylation of the sulfonamide group rendered zafirlukast completely inactive against CRM1. Zafirlukast inhibited the growth of a variety of cancer cells and worked synergistically with the drug doxorubicin. Taken together, these works laid a solid foundation for reshaping zafirlukast as a valuable lead compound for further design of noncovalent, specific, and potent CRM1 inhibitors toward the treatment of various cancers.

Computational and experimental studies of salvianolic acid A targets 3C protease to inhibit enterovirus 71 infection

Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease caused by enterovirus (EV) infection. EV71 is one of the major pathogens causing hand, foot, and mouth disease and is more likely to cause exacerbation and death than other enteroviruses. Although a monovalent vaccine for EV71 has been developed, there are no clinically available anti-EV71 specific drugs. Here, we performed virtual screening and biological experiments based on the traditional Chinese medicine monomer library. We identified a traditional Chinese medicine monomer, Salvianolic acid A (SA), a polyphenolic compound isolated from Salvia miltiorrhiza. Salvianolic acid A inhibits EV71 virus infection in a concentration-dependent manner, and its antiviral activity is higher than that of other reported natural polyphenols and has a high biosafety. Furthermore, molecular dynamics simulations showed that salvianolic acid A can anchor to E71, a member of the enzyme catalytic triad, and cause H40 to move away from the catalytic center. Meanwhile, molecular mechanics generalized born surface area (MMGBSA) and steered molecular dynamics (SMD) results showed that the P1 group of SA was most easily unbound to the S1 pocket of 3C^pro, which provided theoretical support to further improve the affinity of salvianolic acid A with 3C^pro. These findings suggest that salvianolic acid A is a novel EV71 3C^pro inhibitor with excellent antiviral activity and is a promising candidate for clinical studies.

Molecular mechanism of ion channel protein TMEM16A regulated by natural product of narirutin for lung cancer adjuvant treatment

Cancer chemotherapy drugs are widely criticized for their serious side effects and low cure rate. Therefore, adjuvant therapy as a combination with chemotherapy administration is being accepted by many patients. However, unclear drug targets and mechanisms limit the application of adjuvant treatment. In this study, we confirmed TMEM16A is a key drug target for lung adenocarcinoma, and narirutin is an effective anti-lung adenocarcinoma natural product. Virtual screening and fluorescence experiments confirmed that narirutin inhibits the molecular target TMEM16A, which is specific high-expression in lung adenocarcinoma. Molecular dynamics simulations and electrophysiological experiments revealed the precise molecular mechanism of narirutin regulating TMEM16A. The anticancer effect of narirutin and its synergistic effect on cisplatin were explored by cell proliferation, migration, and apoptosis assays. The signaling pathways regulated by narirutin were analyzed by western blot. Tumor xenograft mice experiments demonstrated the synergistic anticancer effect of narirutin and cisplatin, and the side effects of high concentrations of cisplatin were almost eliminated. Pharmacokinetic experiments showed the biological safety of narirutin is satisfactory in vivo. Based on the significant anticancer effect and high biosafety, naringin has great potential as a functional food in the adjuvant treatment of lung cancer.

Multi-target tracheloside and doxorubicin combined treatment of lung adenocarcinoma

Chemotherapy is one of the main methods for malignant lung cancer treatment. However, the side effects of chemotherapy drugs are serious and it is prone to drug resistance. Therefore, multi-drug combination chemotherapy is popular in lung cancer treatment. This study found that tracheloside (TCS) was a novel inhibitor of TMEM16A which was specific high expressed in lung cancer tissues. TCS concentration dependently inhibited TMEM16A with an IC₅₀ of 3.09 ± 0.21 μM. It inhibited lung cancer cells proliferation, migration, and induced cells apoptosis targeting TMEM16A. In addition, molecular docking combined with site-directed mutagenesis confirmed that the binding sites of TCS to TMEM16A were S387, E623, E624. Subsequently, multi-target combined drug administration was conducted based on the different drug targets of TCS and doxorubicin (DOX). Both in vitro and in vivo experiments indicated that the combined administration of low concentration of TCS and DOX achieved satisfactory anticancer effect, and it offset the side effects caused by high concentration of DOX. Therefore, TCS is a safe and efficient anticancer lead compound which can enhance the effect of DOX.

The pharmacology of the TMEM16A channel: therapeutic opportunities

The TMEM16A Ca²⁺-gated Cl^- channel is involved in a variety of vital physiological functions and may be targeted pharmacologically for therapeutic benefit in diseases such as hypertension, stroke, and cystic fibrosis (CF). The determination of the TMEM16A structure and high-throughput screening efforts, alongside ex vivo and in vivo animal studies and clinical investigations, are hastening our understanding of the physiology and pharmacology of this channel. Here, we offer a critical analysis of recent developments in TMEM16A pharmacology and reflect on the therapeutic opportunities provided by this target.

TMEM16A as a potential treatment target for head and neck cancer

Transmembrane protein 16A (TMEM16A) forms a plasma membrane-localized Ca²⁺-activated Cl- channel. Its gene has been mapped to an area on chromosome 11q13, which is amplified in head and neck squamous cell carcinoma (HNSCC). In HNSCC, TMEM16A overexpression is associated with not only high tumor grade, metastasis, low survival, and poor prognosis, but also deterioration of clinical outcomes following platinum-based chemotherapy. Recent study revealed the interaction between TMEM16A and transforming growth factor-β (TGF-β) has an indirect crosstalk in clarifying the mechanism of TMEM16A-induced epithelial-mesenchymal transition. Moreover, human papillomavirus (HPV) infection can modulate TMEM16A expression along with epidermal growth factor receptor (EGFR), whose phosphorylation has been reported as a potential co-biomarker of HPV-positive cancers. Considering that EGFR forms a functional complex with TMEM16A and is a co-biomarker of HPV, there may be crosstalk between TMEM16A expression and HPV-induced HNSCC. EGFR activation can induce programmed death ligand 1 (PD-L1) synthesis via activation of the nuclear factor kappa B pathway and JAK/STAT3 pathway. Here, we describe an interplay among EGFR, PD-L1, and TMEM16A. Combination therapy using TMEM16A and PD-L1 inhibitors may improve the survival rate of HNSCC patients, especially those resistant to anti-EGFR inhibitor treatment. To the best of our knowledge, this is the first review to propose a biological validation that combines immune checkpoint inhibition with TMEM16A inhibition.