Non-small cell lung cancer (NSCLC), EGFR downstream pathway activation and TKI targeted therapies sensitivity: Effect of the plasma membrane-associated NEU3

Regulation of sialic acid metabolism in cancer

Sialic acid, the terminal structure of cell surface glycans, has essential functions in regulating immune response, cell-to-cell communication, and cell adhesion. More importantly, an increased level of sialic acid, termed hypersialylation, has emerged as a commonly observed phenotype in cancer. Therefore, targeting sialic acid ligands (sialoglycans) and their receptors (Siglecs) may provide a new therapeutic approach for cancer immunotherapy. We highlight the complexity of the sialic acid metabolism and its involvement in malignant transformation within individual cancer subtypes. In this review, we focus on the dysregulation of sialylation, the intricate nature of sialic acid synthesis, and clinical perspective. We aim to provide a brief insight into the mechanism of hypersialylation and how our understanding of these processes can be leveraged for the development of novel therapeutics.

Targeting protein glycosylation to regulate inflammation in the respiratory tract: novel diagnostic and therapeutic candidates for chronic respiratory diseases

Protein glycosylation is a widespread posttranslational modification that can impact the function of proteins. Dysregulated protein glycosylation has been linked to several diseases, including chronic respiratory diseases (CRDs). CRDs pose a significant public health threat globally, affecting the airways and other lung structures. Emerging researches suggest that glycosylation plays a significant role in regulating inflammation associated with CRDs. This review offers an overview of the abnormal glycoenzyme activity and corresponding glycosylation changes involved in various CRDs, including chronic obstructive pulmonary disease, asthma, cystic fibrosis, idiopathic pulmonary fibrosis, pulmonary arterial hypertension, non-cystic fibrosis bronchiectasis, and lung cancer. Additionally, this review summarizes recent advances in glycomics and glycoproteomics-based protein glycosylation analysis of CRDs. The potential of glycoenzymes and glycoproteins for clinical use in the diagnosis and treatment of CRDs is also discussed.

Recent Developments and Challenges in Molecular-Targeted Therapy of Non-Small-Cell Lung Cancer

Treatment of lung cancer with conventional therapies, which include radiation, surgery, and chemotherapy results in multiple undesirable adverse or side effects. The major clinical challenge in developing new drug therapies for lung cancer is resistance, which involves mutations and disturbance in various signaling pathways. Molecular abnormalities related to epidermal growth factor receptor (EGFR), v-Raf murine sarcoma viral oncogene homolog B1 (B-RAF) Kirsten rat sarcoma virus (KRAS) mutations, translocation of the anaplastic lymphoma kinase (ALK) gene, mesenchymal-epithelial transition factor (MET) amplification have been studied to overcome the resistance and to develop new therapies for non-small cell lung cancer (NSCLC). But, inevitable development of resistance presents limits the clinical benefits of various new drugs. Here, we review current progress in the development of molecularly targeted therapies, concerning six clinical biomarkers: EGFR, ALK, MET, ROS-1, KRAS, and B-RAF for NSCLC treatment.

Sialyltransferases and Neuraminidases: Potential Targets for Cancer Treatment

Cancers are the leading cause of death, causing around 10 million deaths annually by 2020. The most common cancers are those affecting the breast, lungs, colon, and rectum. However, it has been noted that cancer metastasis is more lethal than just cancer incidence and accounts for more than 90% of cancer deaths. Thus, early detection and prevention of cancer metastasis have the capability to save millions of lives. Finding novel biomarkers and targets for screening, determination of prognosis, targeted therapies, etc., are ways of doing so. In this review, we propose various sialyltransferases and neuraminidases as potential therapeutic targets for the treatment of the most common cancers, along with a few rare ones, on the basis of existing experimental and in silico data. This compilation of available cancer studies aiming at sialyltransferases and neuraminidases will serve as a guide for scientists and researchers working on possible targets for various cancers and will also provide data about the existing drugs which inhibit the action of these enzymes.

alpha2,3 sialic acid processing enzymes expression in gastric cancer tissues reveals that ST3Gal3 but not Neu3 are associated with Lauren's classification, angiolymphatic invasion and histological grade

Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. Despite progress in the last decades, there are still no reliable biomarkers for the diagnosis of and prognosis for GC. Aberrant sialylation is a widespread critical event in the development of GC. Neuraminidases (Neu) and sialyltransferases (STs) regulate the ablation and addition of sialic acid during glycoconjugates biosynthesis, and they are a considerable source of biomarkers in various cancers. This study retrospectively characterized Neu3 and ST3Gal3 expression by immunohistochemistry in 71 paraffin-embedded GC tissue specimens and analyzed the relationship between their expression and the clinicopathological parameters. Neu3 expression was markedly increased in GC tissues compared with non-tumoral tissues (p<0.0001). Intratumoral ST3Gal3 staining was significantly associated with intestinal subtype (p=0.0042) and was negatively associated with angiolymphatic invasion (p=0.0002) and higher histological grade G3 (p=0.0066). Multivariate analysis revealed that ST3Gal3 positivity is able to predict Lauren's classification. No associations were found between Neu3 staining and clinical parameters. The in silico analysis of mRNA expression in GC validation cohorts corroborates the significant ST3Gal3 association with higher histological grade observed in our study. These findings suggest that ST3Gal3 expression may be an indicator for aggressiveness of primary GC.

Review sialidase NEU3 and its pathological significance

Sialidases (EC 3.2.1.18, also called neuraminidases) catalyze the removal of α-glycosidically linked sialic acid residues from glycoproteins and glycolipids; this is the initial step in the degradation of these glycoconjugates. Sialidases of mammalian origin have been implicated in not only lysosomal catabolism but also the modulation of functional molecules involved in many biological processes. To date, four types of mammalian sialidases have been cloned and designated as Neu1, Neu2, Neu3 and Neu4. These sialidases differ in their subcellular localization and enzymatic properties, as well as their chromosomal localization, and they are expressed in a tissue-specific manner. Among the sialidases, the plasma membrane-associated sialidase Neu3 appears to play particular roles in controlling transmembrane signaling through the modulation of gangliosides, and its aberrant expression is closely related to various pathogeneses, including that of cancer. Interestingly, the human orthologue NEU3 acts in two ways, catalytic hydrolysis of gangliosides and protein interactions with other signaling molecules. Aberrant NEU3 expression can induce various pathological conditions. This review briefly summarizes recent studies, focusing on the involvement of NEU3 in various pathological phenomena.

Clinical features and prognosis according to genomic mutations in primary and metastatic lesions of non‐small‐cell lung cancer

Non‐small‐cell lung cancer (NSCLC) is an important cause of cancer‐related death worldwide. The distant metastasis heterogeneity of gene tumor mutations in tumors of NSCLC patients brings critical challenges for treatment. We sequenced the primary tumors and metastatic tissues of 48 NSCLC patients through 363 tumor‐related gene panels to examine gene mutations in primary tumors and metastatic tissues, and screen candidate carcinogenic and metastatic‐related driver mutations. The patient group included 21 patients in the metastatic group and 27 patients in the non‐metastatic group. The patient's median age was 62 years and 54% (26/48) of patients were women. Approximately 75% (36/48) of patients were non‐smokers. The mutation spectrum results showed that epidermal growth factor receptor (EGFR) gene mutation was the most frequent mutation (68.75%), followed by TP53 mutation (45.83%); 19del accounted for the largest proportion of EGFR mutations. Copy number variation (CNV) mutation spectrum results showed that EGFR amplification was more common in the metastatic group than the non‐metastatic group. The mutant‐allele tumor heterogeneity value of the metastatic group was higher than that of the non‐metastatic group (p = 0.013). The progression‐free survival of the metastatic group was significantly shorter than that in the non‐metastatic group (p = 0.041). Single nucleotide variant difference analysis showed that the frequency of TP53 mutations was higher in the metastasis group. The number of subclonal mutations in the primary and metastatic lesions in the metastasis group was significantly different; the number of subclonal sites in metastatic lesions was higher than that in primary lesions. Our results suggested that the gene mutations of NSCLC in primary and metastatic lesions and identified specific mutations related to metastasis of NSCLC. Our research will help to clarify key differences between gene mutations between primary and metastatic NSCLC. These findings will help to provide new theoretical support for the future targeted therapy of metastatic NSCLC.

Human Neuraminidases: Structures and Stereoselective Inhibitors

This Perspective describes the classification, structures, substrates, mechanisms of action, and implications of human neuraminidases (hNEUs) in various pathologies. Some inhibitors have been developed for each isoform, leading to more precise interactions with hNEUs. Although crystal structure data are available for NEU2, most of the findings are based on NEU1 inhibition, and limited information is available for other hNEUs. Therefore, the synthesis of new compounds would facilitate the enrichment of the arsenal of inhibitors to better understand the roles of hNEUs and their mechanisms of action. Nevertheless, due to the already known inhibitors of human neuraminidase enzymes, a structure-activity relationship is presented along with different approaches to inhibit these enzymes for the development of potent and selective inhibitors. Among the different emerging strategies, one is the inhibition of the dimerization of NEU1 or NEU3, and the second is the inhibition of certain receptors located close to hNEU.

Role of NEU3 Overexpression in the Prediction of Efficacy of EGFR-Targeted Therapies in Colon Cancer Cell Lines

The epidermal growth factor receptor (EGFR), through the MAP kinase and PI3K-Akt-mTOR axis, plays a pivotal role in colorectal cancer (CRC) pathogenesis. The membrane-associated NEU3 sialidase interacts with and desialylates EGFR by promoting its dimerization and downstream effectors’ activation. Among the targeted therapies against EGFR, the monoclonal antibody cetuximab is active only in a subgroup of patients not carrying mutations in the MAP kinase pathway. In order to better understand the EGFR-NEU3 interplay and the mechanisms of pharmacological resistance, we investigated the role of NEU3 deregulation in cetuximab-treated CRC cell lines transiently transfected with NEU3 using Western blot analysis. Our results indicate that NEU3 overexpression can enhance EGFR activation only if EGFR is overexpressed, indicating the existence of a threshold for NEU3-mediated EGFR activation. This enhancement mainly leads to the constitutive activation of the MAP kinase pathway. Consequently, we suggest that the evaluation of NEU3 expression cannot entirely substitute the evaluation of EGFR because EGFR-negative cases cannot be stimulated by NEU3. Furthermore, NEU3-mediated hyperactivation of EGFR is counterbalanced by the administration of cetuximab, hypothesizing that a combined treatment of NEU3- and EGFR-targeted therapies may represent a valid option for CRC patients, which must be investigated in the future.

New Target Therapies in Advanced Non-Small Cell Lung Cancer: A Review of the Literature and Future Perspectives

Introduction: Lung cancer (LC) is the most common neoplasm worldwide, and 85% of these tumors are classified as non-small cell lung cancer (NSCLC). LC treatment was initially restricted to cytotoxic chemotherapy—platinum compounds associated with 3rd generation cytotoxic agents (paclitaxel, gemcitabine, pemetrexed) and, more recently, with monoclonal antibodies (bevacizumab, ramucirumab). Advancements in treatment are correlated with prolonged overall survival (OS). Current advances are focused on target therapies. Target agents: Anti-epidermal growth factor receptor (EGFR) therapy consists of 1st and 2nd generation tyrosine kinase inhibitors (TKIs such as erlotinib, afatinib). In 60% of cases, resistance to these TKIs occurs due to T790M mutation in EGFR, which is overcome 3rd generation drugs (osimertinib). Anaplastic lymphoma kinase (ALK) is the target for drugs such as crizotinib, alectinib, ceritinib. Programmed death 1 (PD-1) and its ligand serve as targets for immunotherapy agents such as pembrolizumab, nivolumab, atezolizumab. Discussion: Challenges in NSCLC treatment include resistance to 3rd generation TKIs, the high cost of ALK inhibitors, and the need for further research on new drugs.

Mutant Proteomics of Lung Adenocarcinomas Harboring Different EGFR Mutations

Epidermal growth factor receptor EGFR major driver mutations may affect downstream molecular networks and pathways, which would influence treatment outcomes of non-small cell lung cancer (NSCLC). This study aimed to unveil profiles of mutant proteins expressed in lung adenocarcinomas of 36 patients harboring representative driver EGFR mutations (Ex19del, nine; L858R, nine; no Ex19del/L858R, 18). Surprisingly, the orthogonal partial least squares discriminant analysis performed for identified mutant proteins demonstrated the profound differences in distance among the different EGFR mutation groups, suggesting that cancer cells harboring L858R or Ex19del emerge from cellular origins different from L858R/Ex19del-negative cells. Weighted gene coexpression network analysis, together with over-representative analysis, identified 18 coexpressed modules and their eigen proteins. Pathways enriched differentially for both the L858R and Ex19del mutations included carboxylic acid metabolic process, cell cycle, developmental biology, cellular responses to stress, mitotic prophase, cell proliferation, growth, epithelial to mesenchymal transition (EMT), and immune system. The IPA causal network analysis identified the highly activated networks of PARPBP, HOXA1, and APH1 under the L858R mutation, whereas those of ASGR1, APEX1, BUB1, and MAPK10 were highly activated under the Ex19del mutation. Interestingly, the downregulated causal network of osimertinib intervention showed the highest significance in overlap p-value among most causal networks predicted under the L858R mutation. We also identified the causal network of MAPK interacting serine/threonine kinase 1/2 (MNK1/2) highly activated differentially under the L858R mutation. Tumor-suppressor AMOT, a component of the Hippo pathways, was highly inhibited commonly under both L858R and Ex19del mutations. Our results could identify disease-related protein molecular networks from the landscape of single amino acid variants. Our findings may help identify potential therapeutic targets and develop therapeutic strategies to improve patient outcomes.

Overview of Current Immunotherapies Targeting Mutated KRAS Cancers

The occurrence of somatic substitution mutations of the KRAS proto-oncogene is highly prevalent in certain cancer types, which often leads to constant activation of proliferative pathways and subsequent neoplastic transformation. It is often seen as a gateway mutation in carcinogenesis and has been commonly deemed as a predictive biomarker for poor prognosis and relapse when conventional chemotherapeutics are employed. Additionally, its mutational status also renders EGFR targeted therapies ineffective owing to its downstream location. Efforts to discover new approaches targeting this menacing culprit have been ongoing for years without much success, and with incidences of KRAS positive cancer patients being on the rise, researchers are now turning towards immunotherapies as the way forward. In this scoping review, recent immunotherapeutic developments and advances in both preclinical and clinical studies targeting K-ras directly or indirectly via its downstream signal transduction machinery will be discussed. Additionally, some of the challenges and limitations of various K-ras targeting immunotherapeutic approaches such as vaccines, adoptive T cell therapies, and checkpoint inhibitors against KRAS positive cancers will be deliberated.

TUSC7 suppression of Notch activation through sponging MiR-146 recapitulated the asymmetric cell division in lung adenocarcinoma stem cells

AIMS

Lung adenocarcinoma consists of multiple therapeutic targets, however, patients will inevitably progress to later stage diagnosis with Tyrosine Kinase Inhibitor treatment resistance. We aim to investigate the roles of non-coding TUSC7 in ordering the cell division tendency, helping to sensitize the resistance in a miRNA incorporating way.

MATERIALS AND METHODS

Online study of bioinformatics analysis, molecular experiments of luciferase test, immunofluorescence staining and qRT-PCR were applied to dig out the mechanistic regulations.

KEY FINDINGS

TUSC-7 inhibited the renewal ability of adenocarcinoma stem cells, yielding to asymmetric cell splitting. Informatics analysis and the luciferase testing confirmed the 3'UTR binding site, and revealed the post-transcriptional regulation of NUMB referring to miR-146. TUSC-7 sponged miR-146 and abolished its degradation toward to NUMB, and this integrated cascade made several genes become tangled to full functionality.

SIGNIFICANCE

TUSC-7 was proved to be one strong suppressive lnc-RNA in lung adenocarcinoma stem cells, functioning through inactivating NOTCH signaling, and the turbulence on division modes precisely pointed to the key mechanisms of stem cells' renewal. The decreasing of tumor suppressive miR-146 was necessary in TUSC-7 conducted renewal repression, despite it alone could also reduce the renewal efficiency, indicating that more complicated non-coding genes may be involved in its regulation.

Biological Evaluation and Molecular Dynamics Simulation of Chalcone Derivatives as Epidermal Growth Factor-Tyrosine Kinase Inhibitors

Targeted cancer therapy has become a high potential cancer treatment. Epidermal growth factor receptor (EGFR), which plays an important role in cell signaling, enhanced cell survival and proliferation, has been suggested as molecular target for the development of novel cancer therapeutics. In this study, a series of chalcone derivatives was screened by in vitro cytotoxicity against the wild type (A431 and A549) and mutant EGFR (H1975 and H1650) cancer cell lines, and, subsequently, tested for EGFR-tyrosine kinase (TK) inhibition. From the experimental screening, all chalcones seemed to be more active against the A431 than the A549 cell line, with chalcones 1c, 2a, 3e, 4e, and 4t showing a more than 50% inhibitory activity against the EGFR-TK activity and a high cytotoxicity with IC₅₀ values of < 10 µM against A431 cells. Moreover, these five chalcones showed more potent on H1975 (T790M/L858R mutation) than H1650 (exon 19 deletion E746-A750) cell lines. Only three chalcones (1c, 2a and 3e) had an inhibitory activity against EGFR-TK with a relative inhibition percentage that was close to the approved drug, erlotinib. Molecular dynamics studies on their complexes with EGFR-TK domain in aqueous solution affirmed that they were well-occupied within the ATP binding site and strongly interacted with seven hydrophobic residues, including the important hinge region residue M793. From the above information, as well as ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties, all three chalcones could serve as lead compounds for the development of EGFR-TK inhibitors.

Analyses of the possible anti-tumor effect of yokukansan

The Kampo medicine yokukansan (YKS) has a wide variety of properties such as anxiolytic, anti-inflammatory and analgesic effects, and is also thought to regulate tumor suppression. In this study, we investigated the anti-tumor effect of YKS. We used Lewis lung carcinoma (LLC)-bearing mice that were fed food pellets containing YKS and then performed a fecal microbiota analysis, a microarray analysis for microRNAs (miRNAs) and an in vitro anti-tumor assay. The fecal microbiota analysis revealed that treatment with YKS partly reversed changes in the microbiota composition due to LLC implantation. Furthermore, a miRNA array analysis using blood serum showed that treatment with YKS restored the levels of miR-133a-3p/133b-3p, miR-1a-3p and miR-342-3p following LLC implantation to normal levels. A TargetScan analysis revealed that the epidermal growth factor receptor 1 signaling pathway is one of the major target pathways for these miRNAs. Furthermore, treatment with YKS restored the levels of miR-200b-3p and miR-200c-3p, a recognized mediator of cancer progression and controller of emotion, in the hypothalamus of mice bearing LLC. An in vitro assay revealed that a mixture of pachymic acid, saikosaponins a and d and isoliquiritigenin, which are all contained in YKS, exerted direct and additive anti-tumor effects. The present findings constitute novel evidence that YKS may exert an anti-tumor effect by reversing changes in the fecal microbiota and miRNAs circulating in the blood serum and hypothalamus, and the compounds found in YKS could have direct and additive anti-tumor effects.

Sialidase Attenuates Epidermal Growth Factor Response and Abolishes Antiproliferative Effects of Erlotinib in A549Alveolar Epithelial Cells

Erlotinib is a widely used, reversible tyrosine kinase inhibitor (TKI), targeting pro-proliferative signaling of epidermal growth factor receptor (EGFR). The drug is approved for the first-line treatment of patients with metastatic non-small cell lung cancer with EGFR mutations. Extracellular glycans can affect EGFR expression, dimerization, phosphorylation, and EGF binding. In this study we investigated the effects of EGF and erlotinib on the cell cycle of naive and sialidase (alpha-neuraminidase)-pretreated human A549 alveolar epithelial cells. A549 cells were labeled with propidium iodide, and fractions of cells in different phases of cycle were quantified by flow cytometry. We found that neither did desialilation nor EGF, as well as erlotinib treatment, increase the number of damaged cells (subG0/G1 cell fraction), while erlotinib did significantly increase the number of G0/G1 cells and decrease S + G2/M cell fractions. In naive cells, EGF increased proliferating cell numbers by more than 40%, and this effect was blocked by erlotinib. In desialylated cells, however, proliferation was significantly decreased by about 29%, and EGF and erlotinib did not exert significant effects. We conclude that changes in alveolar epithelial cell membrane glycosylation may affect function of growth-promoting receptors and erlotinib effectiveness.

Sialidase activity in human pathologies

Sialic acid residues are frequently located at the terminal positions of glycoconjugate chains of cellular glycocalyx. Sialidases, or neuraminidases, catalyse removal of these residues thereby modulating various normal and pathological cellular activities. Recent studies have revealed the involvement of sialidases in a wide range of human disorders, including neurodegenerative disorders, cancers, infectious diseases and cardiovascular diseases. The accumulating data make sialidases an interesting potential therapeutic target. Modulating the activity of these enzymes may have beneficial effects in several pathologies. Four types of mammalian sialidases have been described: NEU1, NEU2, NEU3 and NEU4. They are encoded by different genes and characterized by different subcellular localization. In this review, we will summarize the current knowledge on the roles of different sialidases in pathological conditions.