Targeting Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer by Inducing Epidermal Growth Factor Receptor Degradation via Methionine 790 Oxidation

Metabolic profiling and combined therapeutic strategies unveil the cytotoxic potential of selenium-chrysin (SeChry) in NSCLC cells

Lung cancer ranks as the predominant cause of cancer-related mortalities on a global scale. Despite progress in therapeutic interventions, encompassing surgical procedures, radiation, chemotherapy, targeted therapies and immunotherapy, the overall prognosis remains unfavorable. Imbalances in redox equilibrium and disrupted redox signaling, common traits in tumors, play crucial roles in malignant progression and treatment resistance. Cancer cells, often characterized by persistent high levels of reactive oxygen species (ROS) resulting from genetic, metabolic, and microenvironmental alterations, counterbalance this by enhancing their antioxidant capacity. Cysteine availability emerges as a critical factor in chemoresistance, shaping the survival dynamics of non-small cell lung cancer (NSCLC) cells. Selenium-chrysin (SeChry) was disclosed as a modulator of cysteine intracellular availability. This study comprehensively characterizes the metabolism of SeChry and investigates its cytotoxic effects in NSCLC. SeChry treatment induces notable metabolic shifts, particularly in selenocompound metabolism, impacting crucial pathways such as glycolysis, gluconeogenesis, the tricarboxylic acid (TCA) cycle, and amino acid metabolism. Additionally, SeChry affects the levels of key metabolites such as acetate, lactate, glucose, and amino acids, contributing to disruptions in redox homeostasis and cellular biosynthesis. The combination of SeChry with other treatments, such as glycolysis inhibition and chemotherapy, results in greater efficacy. Furthermore, by exploiting NSCLC's capacity to consume lactate, the use of lactic acid-conjugated dendrimer nanoparticles for SeChry delivery is investigated, showing specificity to cancer cells expressing monocarboxylate transporters.

Promoting reactive oxygen species accumulation to overcome tyrosine kinase inhibitor resistance in cancer

BACKGROUND

In tumor treatment, protein tyrosine kinase inhibitors (TKIs) have been extensively utilized. However, the efficacy of TKI is significantly compromised by drug resistance. Consequently, finding an effective solution to overcome TKI resistance becomes crucial. Reactive oxygen species (ROS) are a group of highly active molecules that play important roles in targeted cancer therapy including TKI targeted therapy. In this review, we concentrate on the ROS-associated mechanisms of TKI lethality in tumors and strategies for regulating ROS to reverse TKI resistance in cancer.

MAIN BODY

Elevated ROS levels often manifest during TKI therapy in cancers, potentially causing organelle damage and cell death, which are critical to the success of TKIs in eradicating cancer cells. However, it is noteworthy that cancer cells might initiate resistance pathways to shield themselves from ROS-induced damage, leading to TKI resistance. Addressing this challenge involves blocking these resistance pathways, for instance, the NRF2-KEAP1 axis and protective autophagy, to promote ROS accumulation in cells, thereby resensitizing drug-resistant cancer cells to TKIs. Additional effective approaches inducing ROS generation within drug-resistant cells and providing exogenous ROS stimulation.

CONCLUSION

ROS play pivotal roles in the eradication of tumor cells by TKI. Harnessing the accumulation of ROS to overcome TKI resistance is an effective and widely applicable approach.

Dissecting the pleiotropic roles of reactive oxygen species (ROS) in lung cancer: From carcinogenesis toward therapy

Lung cancer is a major cause of morbidity and mortality. The specific pulmonary structure to directly connect with ambient air makes it more susceptible to damage from airborne toxins. External oxidative stimuli and endogenous reactive oxygen species (ROS) play a crucial role in promoting lung carcinogenesis and development. The biological properties of higher ROS levels in tumor cells than in normal cells make them more sensitive and vulnerable to ROS injury. Therefore, the strategy of targeting ROS has been proposed for cancer therapy for decades. However, it is embarrassing that countless attempts at ROS-based therapies have had very limited success, and no FDA approval in the anticancer list was mechanistically based on ROS manipulation. Even compared with the untargetable proteins, such as transcription factors, ROS are more difficult to be targeted due to their chemical properties. Thus, the pleiotropic roles of ROS provide therapeutic potential for anticancer drug discovery, while a better dissection of the mechanistic action and signaling pathways is a prerequisite for future breakthroughs. This review discusses the critical roles of ROS in cancer carcinogenesis, ROS-inspired signaling pathways, and ROS-based treatment, exemplified by lung cancer. In particular, an eight considerations rule is proposed for ROS-targeting strategies and drug design and development.

Pro-Oxidant Auranofin and Glutathione-Depleting Combination Unveils Synergistic Lethality in Glioblastoma Cells with Aberrant Epidermal Growth Factor Receptor Expression

Glioblastoma (GBM) is the most prevalent and advanced malignant primary brain tumor in adults. GBM frequently harbors epidermal growth factor receptor (EGFR) wild-type (EGFRwt) gene amplification and/or EGFRvIII activating mutation. EGFR-driven GBM relies on the thioredoxin (Trx) and/or glutathione (GSH) antioxidant systems to withstand the excessive production of reactive oxygen species (ROS). The impact of EGFRwt or EGFRvIII overexpression on the response to a Trx/GSH co-targeting strategy is unknown. In this study, we investigated Trx/GSH co-targeting in the context of EGFR overexpression in GBM. Auranofin is a thioredoxin reductase (TrxR) inhibitor, FDA-approved for rheumatoid arthritis. L-buthionine-sulfoximine (L-BSO) inhibits GSH synthesis by targeting the glutamate-cysteine ligase catalytic (GCLC) enzyme subunit. We analyzed the mechanisms of cytotoxicity of auranofin and the interaction between auranofin and L-BSO in U87MG, U87/EGFRwt, and U87/EGFRvIII GBM isogenic GBM cell lines. ROS-dependent effects were assessed using the antioxidant N-acetylsteine. We show that auranofin decreased TrxR1 activity and increased ROS. Auranofin decreased cell vitality and colony formation and increased protein polyubiquitination through ROS-dependent mechanisms, suggesting the role of ROS in auranofin-induced cytotoxicity in the three cell lines. ROS-dependent PARP-1 cleavage was associated with EGFRvIII downregulation in U87/EGFRvIII cells. Remarkably, the auranofin and L-BSO combination induced the significant depletion of intracellular GSH and synergistic cytotoxicity regardless of EGFR overexpression. Nevertheless, molecular mechanisms associated with cytotoxicity were modulated to a different extent among the three cell lines. U87/EGFRvIII exhibited the most prominent ROS increase, P-AKT(Ser-473), and AKT decrease along with drastic EGFRvIII downregulation. U87/EGFRwt and U87/EGFRvIII displayed lower basal intracellular GSH levels and synergistic ROS-dependent DNA damage compared to U87MG cells. Our study provides evidence for ROS-dependent synergistic cytotoxicity of auranofin and L-BSO combination in GBM in vitro. Unraveling the sensitivity of EGFR-overexpressing cells to auranofin alone, and synergistic auranofin and L-BSO combination, supports the rationale to repurpose this promising pro-oxidant treatment strategy in GBM.

Reactive Oxygen Species Modulation in the Current Landscape of Anticancer Therapies

Significance: Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism, and are tightly controlled through homeostatic mechanisms to maintain intracellular redox, regulating growth and proliferation in healthy cells. However, ROS production is perturbed in cancers where abnormal accumulation of ROS leads to oxidative stress and genomic instability, triggering oncogenic signaling pathways on one hand, while increasing oxidative damage and triggering ROS-dependent death signaling on the other. Recent Advances: Our review illuminates how critical interactions between ROS and oncogenic signaling, the tumor microenvironment, and DNA damage response (DDR) pathways have led to interest in ROS modulation as a means of enhancing existing anticancer strategies and developing new therapeutic opportunities. Critical Issues: ROS equilibrium exists via a delicate balance of pro-oxidant and antioxidant species within cells. "Antioxidant" approaches have been explored mainly in the form of chemoprevention, but there is insufficient evidence to advocate its routine application. More progress has been made via the "pro-oxidant" approach of targeting cancer vulnerabilities and inducing oxidative stress. Various therapeutic modalities have employed this approach, including direct ROS-inducing agents, chemotherapy, targeted therapies, DDR therapies, radiotherapy, and immunotherapy. Finally, emerging delivery systems such as "nanosensitizers" as radiotherapy enhancers are currently in development. Future Directions: While approaches designed to induce ROS have shown considerable promise in selectively targeting cancer cells and dealing with resistance to conventional therapies, most are still in early phases of development and challenges remain. Further research should endeavor to refine treatment strategies, optimize drug combinations, and identify predictive biomarkers of ROS-based cancer therapies.

EGFR degraders in non-small-cell lung cancer: Breakthrough and unresolved issue

The epidermal growth factor receptor (EGFR) has been well validated as a therapeutic target for anticancer drug discovery. Osimertinib has become the first globally accessible third-generation EGFR inhibitor, representing one of the most advanced developments in non-small-cell lung cancer (NSCLC) therapy. However, a tertiary Cys797 to Ser797 (C797S) point mutation has hampered osimertinib treatment in patients with advanced EGFR-mutated NSCLC. Several classes of fourth-generation EGFR inhibitors were consequently discovered with the aim of overcoming the EGFRC797S mutation-mediated resistance. However, no clinical efficacy data of the fourth-generation EGFR inhibitors were reported to date, and EGFRC797S mutation-mediated resistance remains an "unmet clinical need." Proteolysis-targeting chimeric molecules (PROTACs) obtained from EGFR-TKIs have been developed to target drug resistance EGFR in NSCLC. Some PROTACs are from nature products. These degraders compared with EGFR inhibitors showed better efficiency in their cellular potency, inhibition, and toxicity profiles. In this review, we first introduce the structural properties of EGFR, the resistance, and mutations of EGFR, and then mainly focus on the recent advances of EGFR-targeting degraders along with its advantages and outstanding challenges.

Tetrahydrobenzothiophene derivatives ameliorate Mia PaCa-2 cell progression and induces apoptosis via inhibiting EGFR2 tyrosine kinase signal

A series of new thiophene analogues with acarbonitrile-basedmoiety were designed and synthesized via structural optimization. The conjugates were assessed for their in-vitro cytotoxic activity against a human pancreatic cancer cell line (Mia PaCa-2) and among them compound 5b showed IC50 value of 13.37 ± 2.37 μM. The compounds 5b (20 µM & 25 µM) and 7c (30 & 35 µM) also showed reduced clonogenicity, enhanced ROS and decreased mitochondrial membrane potential in Mia PaCa-2 cells. Treatment with these compounds also increased apoptotic population as evident with the double staining assay. Among the evaluated series, compounds 5b, 5g, 7c, and 9a attained a greater inhibitory potency than first generation's reversible EGFR inhibitor, Gefitinib. EGFR2 enzyme inhibitory studies revealed that 5b efficiently and arbitrarily suppressed the development of EGFR2 dependent cells and inhibited the enzymatic activity with an IC50 value of 0.68 µM; interestingly, the most effective molecule 5b with N-methyl piperazine substitution, has 1.29-fold greater potency than well-known EGFR inhibitor Gefitinib and increased Gefitinib's anti-growth impact with 2.04 folds greater against Mia PaCa-2. The in-vitro studies were validated with in-silico docking studies wherein compounds 5b and 7c exhibited binding energies of -8.2 and -7.4 Kcal/mol respectively. The present study reveals that tetrahydrobenzothiophene based analogues could be a promising lead for the evolution of potent chemo preventives over pancreatic cancer.

The cell line models to study tyrosine kinase inhibitors in non-small cell lung cancer with mutations in the epidermal growth factor receptor: A scoping review

Non-Small Cell Lung Cancer (NSCLC) represents ∼85% of all lung cancers and ∼15-20% of them are characterized by mutations affecting the Epidermal Growth Factor Receptor (EGFR). For several years now, a class of tyrosine kinase inhibitors was developed, targeting sensitive mutations affecting the EGFR (EGFR-TKIs). To date, the main burden of the TKIs employment is due to the onset of resistance mutations. This scoping review aims to resume the current situation about the cell line models employed for the in vitro evaluation of resistance mechanisms induced by EGFR-TKIs in oncogene-addicted NSCLC. Adenocarcinoma results the most studied NSCLC histotype with the H1650, H1975, HCC827 and PC9 mutated cell lines, while Gefitinib and Osimertinib the most investigated inhibitors. Overall, data collected frame the current advancement of this topic, showing a plethora of approaches pursued to overcome the TKIs resistance, from RNA-mediated strategies to the innovative combination therapies.

Development of a NIR fluorescent probe for fluorescence-assisted EGFR-TKI applicable patients screening and drug resistance monitoring

EGFR tyrosine kinase inhibitor exerts significant benefits to non-small cell lung cancer patient, but was also limited by the applicable patient screening and drug resistance. Here we presented with an EGFR-targeted and reactive oxygen species-responsive NIR probe (LX) to achieve both patient screening and drug resistance monitoring for EGFR-tyrosine kinase inhibitor. LX inherited EGFR selectivity and preference from EGFR-tyrosine kinase inhibitor, which only showed specificity to tumor with EGFR mutation. Meanwhile, the near-infrared fluorescence of LX was initially inhibited and could be turned on by intratumoral reactive oxygen species. When LX could bind to tumor EGFR, reactive oxygen species-responsive specific fluorescence was generated to indicate the applicability of tumors to EGFR-tyrosine kinase inhibitor. However, no specific LX fluorescence could be observed in inapplicable tumors due to the lack of specificity between tumor EGFR and LX. Meanwhile, when drug resistance was developed during treatments, obvious intratumoral reactive species oxygen decrease happened, which was also deemed as a significant signal of the drug resistance. By visualizing intratumoral reactive oxygen species fluctuation by responsive fluorescence, drug resistance could be monitored and reported.

Inhibiting G6PD by quercetin promotes degradation of EGFR T790M mutation

EGFRT790M mutation causes resistance to the first-generation tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). However, the therapeutic options for sensitizing first TKIs and delaying the emergence of EGFRT790M mutant are limited. In this study, we show that quercetin directly binds with glucose-6-phosphate dehydrogenase (G6PD) and inhibits its enzymatic activity through competitively abrogating NADP+ binding in the catalytic domain. This inhibition subsequently reduces intracellular NADPH levels, resulting in insufficient substrate for methionine reductase A (MsrA) to reduce M790 oxidization of EGFRT790M and inducing the degradation of EGFRT790M. Quercetin synergistically enhances the therapeutic effect of gefitinib on EGFRT790M-harboring NSCLCs and delays the acquisition of the EGFRT790M mutation. Notably, high levels of G6PD expression are correlated with poor prognosis and the emerging time of EGFRT790M mutation in patients with NSCLC. These findings highlight the potential implication of quercetin in overcoming EGFRT790M-driven TKI resistance by directly targeting G6PD.

Shielding and nurturing: Fibronectin as a modulator of cancer drug resistance

Resistance to chemotherapy and targeted therapies constitute a common hallmark of most cancers and represent a dominant factor fostering tumor relapse and metastasis. Fibronectin, an abundant extracellular matrix glycoprotein, has long been proposed to play an important role in the pathobiology of cancer. Recent research has unraveled the role of Fibronectin in the onset of chemoresistance against a variety of antineoplastic drugs including DNA-damaging agents, hormone receptor antagonists, tyrosine kinase inhibitors, microtubule destabilizing agents, etc. The current review summarizes the role played by Fibronectin in mediating drug resistance against diverse anticancer drugs. We have also discussed how the aberrant expression of Fibronectin drives the oncogenic signaling pathways ultimately leading to drug resistance through the inhibition of apoptosis, promotion of cancer cell growth and proliferation.

The Ethyl acetate extract from Celastrus orbiculatus suppresses non-small-cell lung cancer by activating Hippo signaling and inhibiting YAP nuclear translocation

BACKGROUND

Celastrus orbiculatus Thunb. is a medicinal plant that has been widely used for thousands of years in China, and the ethyl acetate extract (Celastrus orbiculatus Thunb. Extract, COE) from its stem was reported to exert antitumor and anti-inflammatory effects in various preclinical studies. However, the anti-non-small-cell lung cancer activity of COE and its potential mechanism are not yet fully understood.

PURPOSE

To investigate the antitumor effects of COE on non-small-cell lung cancer (NSCLC) cells and explore its molecular mechanism from the perspective of Hippo signaling, YAP nuclear translocation, and reactive oxygen species (ROS) generation.

METHODS

The effects of COE on proliferation, cell cycle arrest, apoptosis, stemness, and senescence in NSCLC cell lines were determined by CCK-8, clone formation, flow cytometry, and β-galactosidase staining assays. The effects of COE on Hippo signaling were investigated by Western blotting. The intracellular expression and distribution of YAP were analyzed by immunofluorescence assay. DCFH-DA probe combined with flow cytometry was used to detect intracellular total ROS levels in NSCLC cells after COE treatment. Xenograft tumor model was established, and the animal living image system was employed to analyze the effects of COE on the Hippo-YAP signaling in vivo.

RESULT

COE significantly inhibited NSCLC activity in vitro and in vivo, mainly by proliferation inhibition, cycle arrest, apoptosis promotion, senescence promotion, and stemness downregulation. COE strongly activated Hippo signaling and inhibited YAP expression and nuclear retention. Activation of Hippo signaling induced by COE was associated with ROS-mediated phosphorylation of MOB1.

CONCLUSION

This study demonstrated that COE inhibited NSCLC through activating Hippo signaling and suppressing YAP nuclear translocation, in which ROS may play a role in the phosphorylation of the MOB1 protein.

Insights into the potential of Sanguinarine as a promising therapeutic option for breast cancer

Breast cancer (BC) is one of the leading causes of cancer-related deaths in women worldwide. The tumor microenvironment (TME) plays a crucial role in the progression and metastasis of BC. A significant proportion of BC is characterized by a hypoxic TME, which contributes to the development of drug resistance and cancer recurrence. Sanguinarine (SAN), an isoquinoline alkaloid found in Papaver plants, has shown promise as an anticancer agent. The present review focuses on exploring the molecular mechanisms of hypoxic TME in BC and the potential of SAN as a therapeutic option. The review presents the current understanding of the hypoxic TME, its signaling pathways, and its impact on the progression of BC. Additionally, the review elaborates on the mechanisms of action of SAN in BC, including its effects on vital cellular processes such as proliferation, migration, drug resistance, and tumor-induced immune suppression. The review highlights the importance of addressing hypoxic TME in treating BC and the potential of SAN as a promising therapeutic option.

Tumor PKCδ instigates immune exclusion in EGFR-mutated non-small cell lung cancer

BACKGROUND

The recruitment of a sufficient number of immune cells to induce an inflamed tumor microenvironment (TME) is a prerequisite for effective response to cancer immunotherapy. The immunological phenotypes in the TME of EGFR-mutated lung cancer were characterized as non-inflamed, for which immunotherapy is largely ineffective.

METHODS

Global proteomic and phosphoproteomic data from lung cancer tissues were analyzed aiming to map proteins related to non-inflamed TME. The ex vivo and in vivo studies were carried out to evaluate the anti-tumor effect. Proteomics was applied to identify the potential target and signaling pathways. CRISPR-Cas9 was used to knock out target genes. The changes of immune cells were monitored by flow cytometry. The correlation between PKCδ and PD-L1 was verified by clinical samples.

RESULTS

We proposed that PKCδ, a gatekeeper of immune homeostasis with kinase activity, is responsible for the un-inflamed phenotype in EGFR-mutated lung tumors. It promotes tumor progression by stimulating extracellular matrix (ECM) and PD-L1 expression which leads to immune exclusion and assists cancer cell escape from T cell surveillance. Ablation of PKCδ enhances the intratumoral penetration of T cells and suppresses the growth of tumors. Furthermore, blocking PKCδ significantly sensitizes the tumor to immune checkpoint blockade (ICB) therapy (αPD-1) in vitro and in vivo model.

CONCLUSIONS

These findings revealed that PKCδ is a critical switch to induce inflamed tumors and consequently enhances the efficacy of ICB therapy in EGFR-mutated lung cancer. This opens a new avenue for applying immunotherapy against recalcitrant tumors.

Sanguinarine Regulates Tumor-Associated Macrophages to Prevent Lung Cancer Angiogenesis Through the WNT/β-Catenin Pathway

Tumor-associated macrophage (TAM)-mediated angiogenesis in the tumor microenvironment is a prerequisite for lung cancer growth and metastasis. Therefore, targeting TAMs, which block angiogenesis, is expected to be a breakthrough in controlling the growth and metastasis of lung cancer. In this study, we found that Sanguinarine (Sang) inhibits tumor growth and tumor angiogenesis of subcutaneously transplanted tumors in Lewis lung cancer mice. Furthermore, Sanguinarine inhibited the proliferation, migration, and lumen formation of HUVECs and the expression of CD31 and VEGF by regulating the polarization of M2 macrophages in vitro. However, the inhibitory effect of Sanguinarine on angiogenesis remained in vivo despite the clearance of macrophages using small molecule drugs. Further high-throughput sequencing suggested that WNT/β-Catenin signaling might represent the underlying mechanism of the beneficial effects of Sanguinarine. Finally, the β-Catenin activator SKL2001 antagonized the effect of Sanguinarine, indicating that Sanguinarine can regulate M2-mediated angiogenesis through the WNT/β-Catenin pathway. In conclusion, this study presents the first findings that Sanguinarine can function as a novel regulator of the WNT/β-Catenin pathway to modulate the M2 macrophage polarization and inhibit angiogenesis, which has potential application value in immunotherapy and antiangiogenic therapy for lung cancer.

Recent advances in the development of EGFR degraders: PROTACs and LYTACs

Epidermal Growth Factor Receptor (EGFR), a transmembrane tyrosine kinase receptor, belongs to the ErbB receptor family, also known as HER1 or ErbB1. Its abnormal expression and activation contribute to tumor development, especially in non-small cell lung cancer (NCSCL). The first-to fourth-generation inhibitors of EGFR were developed to solve mutations at different sites, but the problem of resistance has not been fundamentally addressed. Targeted protein degradation (TPD) technologies, including PROteolysis Targeting Chimeras (PROTACs) and LYsosome Targeting Chimeras (LYTACs), take advantages of protein destruction mechanism in cells, which make up for shortcomings of traditional small molecular occupancy-driven inhibitors. PROTACs based heterobifunctional EGFR degraders were recently developed by making use of wild-type (WT) and mutated EGFR inhibitors. These degraders compared with EGFR inhibitors showed better efficiency in their cellular potency, inhibition and toxicity profiles. In this review, we first introduce the structural properties of EGFR, the inhibitors that have been developed against WT/mutated EGFR, and then mainly focuses on the recent advances of EGFR-targeting degraders along with its limitations and unlimited prospects.

FGFC1 Selectively Inhibits Erlotinib-Resistant Non-Small Cell Lung Cancer via Elevation of ROS Mediated by the EGFR/PI3K/Akt/mTOR Pathway

Non-small cell lung cancer (NSCLC) is one of the most common malignancies in the world. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have been used as a first-line treatment for patients harboring with EGFR mutations in advanced NSCLC. Nevertheless, the drug resistance after continuous and long-term chemotherapies considerably limits its clinical efficacy. Therefore, it is of great importance to develop new chemotherapeutic agents and treatment strategies to conquer the drug resistance. FGFC1 (Fungi fibrinolytic compound 1), a type of bisindole alkaloid from a metabolite of the rare marine fungi Starchbotrys longispora. FG216, has exhibited excellent fibrinolytic and anti-inflammatory activity. However, the potent efficacy of FGFC1 in human cancer therapy requires further study. Herein, we demonstrated that FGFC1 selectively suppressed the growth of NSCLC cells with EGFR mutation. Mechanistically, FGFC1 treatment significantly induced the apoptosis of erlotinib-resistant NSCLC cells H1975 in a dose-dependent manner, which was proved to be mediated by mitochondrial dysfunction and elevated accumulation of intracellular reactive oxygen species (ROS). Scavenging ROS not only alleviated FGFC1-induced apoptosis but also relieved the decrease of phospho-Akt. We further confirmed that FGFC1 significantly decreased the phosphorylation of protein EGFR, phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), and mammalian target of rapamycin (mTOR) in H1975 cells. Notably, PI3K inhibitor (LY294002) could promote the accumulation of ROS and the expression levels of apoptosis-related proteins induced by FGFC1. Molecular dynamics simulations indicated that FGFC1 can inhibit EGFR and its downstream PI3K/Akt/mTOR pathway through directly binding to EGFR, which displayed a much higher binding affinity to EGFRT790M/L858R than EGFRWT. Additionally, FGFC1 treatment also inhibited the migration and invasion of H1975 cells. Finally, FGFC1 effectively inhibited tumor growth in the nude mice xenograft model of NSCLC. Taken together, our results indicate that FGFC1 may be a potential candidate for erlotinib-resistant NSCLC therapy.

Reactive oxygen species (ROS) in cancer pathogenesis and therapy: An update on the role of ROS in anticancer action of benzophenanthridine alkaloids

Reactive oxygen species play crucial role in biological homeostasis and pathogenesis of human diseases including cancer. In this line, now it has become evident that ROS level/concentration is a major factor in the growth, progression and stemness of cancer cells. Moreover, cancer cells maintain a delicate balance between ROS and antioxidants to promote pathogenesis and clinical challenges via targeting a battery of signaling pathways converging to cancer hallmarks. Recent findings also entail the therapeutic importance of ROS for the better clinical outcomes in cancer patients as they induce apoptosis and autophagy. Moreover, poor clinical outcomes associated with cancer therapies are the major challenge and use of natural products have been vital in attenuation of these challenges due to their multitargeting potential with less adverse effects. In fact, most available drugs are derived from natural resources, either directly or indirectly and available evidence show the clinical importance of natural products in the management of various diseases, including cancer. ROS play a critical role in the anticancer actions of natural products, particularly phytochemicals. Benzophenanthridine alkaloids of the benzyl isoquinoline family of alkaloids, such as sanguinarine, possess several pharmacological properties and are thus being studied for the treatment of different human diseases, including cancer. In this article, we review recent findings, on how benzophenanthridine alkaloid-induced ROS play a critical role in the attenuation of pathological changes and stemness features associated with human cancers. In addition, we highlight the role of ROS in benzophenanthridine alkaloid-mediated activation of the signaling pathway associated with cancer cell apoptosis and autophagy.

Role of NRF2 in Lung Cancer

The gene expression program induced by NRF2 transcription factor plays a critical role in cell defense responses against a broad variety of cellular stresses, most importantly oxidative stress. NRF2 stability is fine-tuned regulated by KEAP1, which drives its degradation in the absence of oxidative stress. In the context of cancer, NRF2 cytoprotective functions were initially linked to anti-oncogenic properties. However, in the last few decades, growing evidence indicates that NRF2 acts as a tumor driver, inducing metastasis and resistance to chemotherapy. Constitutive activation of NRF2 has been found to be frequent in several tumors, including some lung cancer sub-types and it has been associated to the maintenance of a malignant cell phenotype. This apparently contradictory effect of the NRF2/KEAP1 signaling pathway in cancer (cell protection against cancer versus pro-tumoral properties) has generated a great controversy about its functions in this disease. In this review, we will describe the molecular mechanism regulating this signaling pathway in physiological conditions and summarize the most important findings related to the role of NRF2/KEAP1 in lung cancer. The focus will be placed on NRF2 activation mechanisms, the implication of those in lung cancer progression and current therapeutic strategies directed at blocking NRF2 action.

Plumbagin suppresses non-small cell lung cancer progression through downregulating ARF1 and by elevating CD8+ T cells

Non-small cell lung cancer (NSCLC) is one of the most frequently diagnosed cancers and the leading causes of cancer death worldwide. Therefore, new therapeutic agents are urgently needed to improve patient outcomes. Plumbagin (PLB), a natural sesquiterpene present in many Chinese herbal medicines, has been reported for its anti-cancer activity in various cancer cells. In this study, the effects and underlying mechanisms of PLB on the tumorigenesis of NSCLC were investigated. PLB dose-dependently inhibited the growth of NSCLC cell lines. PLB promoted ROS production, activated the endoplasmic reticulum (ER) stress pathway, and induced cell apoptosis, accompanied by the decreased expression level of ADP-ribosylation factor 1 (ARF1) in NSCLC cancer cells, and those effects of PLB could be reversed by the pretreatment with N-acetyl-L-cysteine (NAC). More importantly, the calcium chelator (BM) significantly reversed PLB-induced cell apoptosis. Furthermore, PLB significantly inhibited the growth of both H1975 xenograft and LLC1 tumors and exhibited antitumor activity by enhancing the number and the effector function of CD8+ T cells in KRASLA2 mice model and the LLC1 xenograft. Our findings suggest that PLB exerts potent antitumor activity against NSCLC in vitro and in vivo through ARF1 downregulation and induction of antitumor immune response, indicating that PLB is a new novel therapeutic candidate for the treatment of patients with NSCLC.

The novel FAT4 activator jujuboside A suppresses NSCLC tumorigenesis by activating HIPPO signaling and inhibiting YAP nuclear translocation

FAT atypical cadherin 4 (FAT4) has been identified as a tumor suppressor in lung cancers. However, no agent for lung cancer treatment targeting FAT4 has been used in the clinic. Jujuboside A (JUA) is a major active compound in Semen Ziziphi Spinosae. Semen Ziziphi Spinosae is a traditional Chinese herbal medicine used clinically for tumor treatment to improve patients' quality of life. However, the anti-lung cancer activity and the underlying mechanisms of JUA are not yet fully understood. Here, we demonstrated the anti-lung cancer activity of JUA in two lung cancer mice models and three non-small cell lung cancer (NSCLC) cell lines, and further illustrated its underlying mechanisms. JUA suppressed the occurrence and development of lung cancer and extended mice survival in vivo, and suppressed NSCLC cell activities through cell cycle arrest, proliferation suppression, stemness inhibition and senescence promotion. Moreover, JUA directly bound with and activated FAT4, subsequently activating FAT4-HIPPO signaling and inhibiting YAP nuclear translocation. Knockdown of FAT4 diminished JUA's effects on HIPPO signaling, YAP nuclear translocation, cell proliferation and cellular senescence. In conclusion, JUA significantly suppressed NSCLC tumorigenesis by regulating FAT4-HIPPO-YAP signaling. Our findings suggest that JUA is a novel FAT4 activator that can be developed as a promising NSCLC therapeutic agent targeting the FAT4-HIPPO-YAP pathway.

STAMBP promotes lung adenocarcinoma metastasis by regulating the EGFR/MAPK signaling pathway

Tumor metastasis is a leading cause of death in lung adenocarcinoma (LUAD) patients, but the molecular events that regulate metastasis have not been completely elucidated. STAMBP is a deubiquitinating enzyme of the Jab1/MPN metalloenzyme family that regulates the stability of substrates in cells by specifically removing ubiquitin molecules. We found that STAMBP expression was increased in the cytoplasm of tumor cells from LUAD patients. The STAMBP level was closely associated with tumor size, lymph node invasion and neoplasm disease stage. A high STAMBP level predicted poor overall survival and disease-free survival in LUAD patients. STAMBP overexpression promoted cell migration and invasion, whereas STAMBP knockdown attenuated these processes in LUAD cells after epidermal growth factor treatment. Mechanistically, increased STAMBP expression promoted the stabilization of Epidermal growth factor receptor (EGFR), whereas STAMBP knockdown induced the degradation of EGFR. STAMBP may deubiquitinate EGFR by localizing in early endosomes and increase EGFR membrane localization in LUAD cells. The overexpression of STAMBP triggered the activation of MAPK signaling after epidermal growth factor treatment. In contrast, this activation was attenuated in STAMBP knockdown cells. Small molecule inhibitors of EGFR and MAPK signaling pathway may block STAMBP-induced cell mobility and invasion as well as ERK activation in cells. Importantly, STAMBP knockdown suppressed LUAD tumor growth and metastasis by regulating the EGFR-mediated ERK activation in a xenograft mouse model. Our findings identified STAMBP as a novel potential target for LUAD therapy.

Roles of Ion Fluxes, Metabolism, and Redox Balance in Cancer Therapy

Recent Advances: The 2019 Nobel Prize awarded to the mechanisms for oxygen sensing and adaptation according to oxygen availability, highlighting the fundamental importance of gaseous molecules. Gaseous molecules, including reactive oxygen species (ROS), can interact with different cations generated during metabolic and redox dysregulation in cancer cells. Cross talk between calcium signaling and metabolic/redox pathways leads to network-based dyregulation in cancer. Significance: Recent discovery on using small molecules targeting the ion channels, redox signaling, and protein modification on metabolic enzymes can effectively inhibit cancer growth. Several FDA-approved drugs and clinical trials are ongoing to target the calcium channels, such as TRPV6 and TRPM8. Multiple small molecules from natural products target metablic and redox enzymes to exert an anticancer effect. Critical Issues: Small molecules targeting key ion channels, metabolic enzymes that control key aspects of metabolism, and redox proteins are promising, but their action mechanisms of the target are needed to be elucidated with advanced-omic technologies, which can give network-based and highly dimensioal data. In addition, small molecules that can directly modify the protein residues have emerged as a novel anticancer strategy. Future Directions: Advanced technology accelerates the detection of ions and metabolic and redox changes in clinical samples for diagnosis and informs the decision of cancer treatment. The improvement of ROS detection, ROS target identification, and computational-aid drug discovery also improves clincal outcome.Overall, network-based or holistic regulations of cancer via ion therapy and metabolic and redox intervention are promising as new anticancer strategies. Antioxid. Redox Signal. 34, 1108-1127.

Antrodia camphorata extract (ACE)-induced apoptosis is associated with BMP4 expression and p53-dependent ROS generation in human colon cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Antrodia camphorata (AC) is a rare functional fungus in Taiwan and is known as traditional Chinese medicine. It has been reported to inhibit proliferation and promote apoptosis in human cancer cells.

AIM OF THE STUDY

To investigate the potential mechanism of apoptosis induced in colon cancer cells by Antrodia camphorata extract (ACE).

MATERIALS AND METHODS

The MTT assay and crystal violet staining were used to determine relative cell viability in vitro at 24 and 48 h. The effects of ACE on apoptosis were determined by Hoechst 33342 staining and flow cytometric analysis following Annexin V-FITC/PI staining. The gene expression profile of HCT116 cells was assessed by the RNA sequencing system. In combination with RNA-seq data and qRT-PCR, Western blot analysis was used to evaluate expression of proteins. The intracellular ROS of HCT116 cells were determined using a DCFH-DA fluorescence probe.

RESULTS

ACE significantly reduces cell viability in a dose-dependent manner and triggers apoptosis. To explore the underlying mechanism, we performed transcriptome analysis of ACE-treated colon cancer HCT116 cells. Bioinformatics analyses showed that ACE treatment is associated with pathways in cancer. We further used Cytoscape to analyze hub genes in this network. Among them, BMP4, which is associated with cancer cell death through regulation of the tumor suppressor p53, was significantly decreased at both mRNA and protein levels in ACE treatment groups. We found that cell death is reversible via inactivation or knockdown of p53 gene and reduction of reactive oxygen species (ROS) generation in response to ACE exposure, indicating that p53 plays an important role in ROS generation induced by ACE. Meanwhile, ROS scavenger NAC was used to verify that cell death is reversible via reduction of ROS.

CONCLUSION

Our findings demonstrate that ACE has potential as an anticancer agent that induces apoptosis through BMP4 and p53-dependent response to ROS in human colon cancer.

Nicotinamide adenine dinucleotide phosphate oxidase inhibitor induces apoptosis on Epstein-Barr virus positive B lymphoma cells

Over-expression of nicotinamide adenine dinucleotide phosphate oxidase (Nox) isoform enzymes was recently reported in various cancers including Burkitt’s lymphoma (BL). However, the functions of Nox isoform enzymes in BL remain poorly understood. In this study, Nox isoform expression and the effects of a Nox-specific inhibitor were evaluated in Epstein-Barr virus (EBV)-positive Raji BL cells in comparison with EBV-negative Ramos BL cells. To evaluate Nox enzyme expression in Raji and Ramos BL cells, polymerase chain reaction (PCR) and western blot analysis were performed. To verify the intracellular signaling mechanism of the Nox inhibitor-induced apoptosis of Raji cells, WST-1 assay, trypan blue exclusion method, flow cytometry, PCR, western blotting, and bromodeoxyuridine staining were conducted. Experiments using the pan-caspase inhibitor z-VAD, reactive oxygen species scavenger N-acetyl-L-cysteine (NAC), and Bim inhibitor 1 were performed. PCR and western blot results showed that Nox isoform enzymes were highly expressed in EBV-positive BL Raji cells compared with EBV-negative BL Ramos cells. The Nox2 inhibitor induced apoptosis of Raji cells in time- and dose-dependent manners. The Nox2 inhibitor also caused up-regulation of Bim and Noxa, down-regulation of Mcl-1, translocation of Bax, release of cytochrome c, and caspase cascade activation, resulting in apoptosis. Furthermore, z-VAD, NAC, and BI-1 effectively blocked the Nox2 inhibitor-induced apoptosis of Raji cells. Taken together, these results provide a novel insight into the mechanism of Nox inhibitor-induced apoptosis and evidence for Nox as a therapeutic target to treat EBV-positive malignancies.

Nrf2 Mediates Metabolic Reprogramming in Non-Small Cell Lung Cancer

Nuclear factor erythroid-2–related factor-2 (NFE2L2/Nrf2) is a transcription factor that regulates the expression of antioxidant genes. Both Kelch-like ECH-associated protein 1 (Keap1) mutations and Nrf2 mutations contribute to the activation of Nrf2 in non-small cell lung cancer (NSCLC). Nrf2 activity is associated with poor prognosis in NSCLC. Metabolic reprogramming represents a cancer hallmark. Increasing studies reveal that Nrf2 activation promotes metabolic reprogramming in cancer. In this review, we discuss the underlying mechanisms of Nrf2-mediated metabolic reprogramming and elucidate its role in NSCLC. Inhibition of Nrf2 can alter metabolic processes, thus suppress tumor growth, prevent metastasis, and increase sensitivity to chemotherapy in NSCLC. In conclusion, Nrf2 may serve as a therapeutic target for the treatment of NSCLC.

Evodiamine suppresses non-small cell lung cancer by elevating CD8+ T cells and downregulating the MUC1-C/PD-L1 axis

Background

Accumulating evidence showed that regulating tumor microenvironment plays a vital role in improving antitumor efficiency. Programmed Death Ligand 1 (PD-L1) is expressed in many cancer cell types, while its binding partner Programmed Death 1 (PD1) is expressed in activated T cells and antigen-presenting cells. Whereas, its dysregulation in the microenvironment is poorly understood. In the present study, we confirmed that evodiamine downregulates MUC1-C, resulting in modulating PD-L1 expression in non-small cell lung cancer (NSCLC).

Methods

Cell viability was measured by MTT assays. Apoptosis, cell cycle and surface PD-L1 expression on NSCLC cells were analyzed by flow cytometry. The expression of MUC1-C and PD-L1 mRNA was measured by real time RT-PCR methods. Protein expression was examined in evodiamine-treated NSCLC cells using immunoblotting or immunofluorescence assays. The effects of evodiamine treatment on NSCLC sensitivity towards T cells were investigated using human peripheral blood mononuclear cells and Jurkat, apoptosis and IL-2 secretion assays. Female H1975 xenograft nude mice were used to assess the effect of evodiamine on tumorigenesis in vivo. Lewis lung carcinoma model was used to investigate the therapeutic effects of combination evodiamine and anti-PD-1 treatment.

Results

We showed that evodiamine significantly inhibited growth, induced apoptosis and cell cycle arrest at G2 phase of NSCLC cells. Evodiamine suppressed IFN-γ-induced PD-L1 expression in H1975 and H1650. MUC1-C mRNA and protein expression were decreased by evodiamine in NSCLC cells as well. Evodiamine could downregulate the PD-L1 expression and diminish the apoptosis of T cells. It inhibited MUC1-C expression and potentiated CD8⁺ T cell effector function. Meanwhile, evodiamine showed good anti-tumor activity in H1975 tumor xenograft, which reduced tumor size. Evodiamine exhibited anti-tumor activity by elevation of CD8⁺ T cells in vivo in Lewis lung carcinoma model. Combination evodiamine and anti-PD-1 mAb treatment enhanced tumor growth control and survival of mice.

Conclusions

Evodiamine can suppress NSCLC by elevating of CD8⁺ T cells and downregulating of the MUC1-C/PD-L1 axis. Our findings uncover a novel mechanism of action of evodiamine and indicate that evodiamine represents a potential targeted agent suitable to be combined with immunotherapeutic approaches to treat NSCLC cancer patients. MUC1-C overexpression is common in female, non-smoker, patients with advanced-stage adenocarcinoma.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s13046-020-01741-5.

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.

Discovery of a novel EGFR ligand DPBA that degrades EGFR and suppresses EGFR-positive NSCLC growth

Epidermal growth factor receptor (EGFR) activation plays a pivotal role in EGFR-driven non-small cell lung cancer (NSCLC) and is considered as a key target of molecular targeted therapy. EGFR tyrosine kinase inhibitors (TKIs) have been canonically used in NSCLC treatment. However, prevalent innate and acquired resistances and EGFR kinase-independent pro-survival properties limit the clinical efficacy of EGFR TKIs. Therefore, the discovery of novel EGFR degraders is a promising approach towards improving therapeutic efficacy and overcoming drug resistance. Here, we identified a 23-hydroxybetulinic acid derivative, namely DPBA, as a novel EGFR small-molecule ligand. It exerted potent in vitro and in vivo anticancer activity in both EGFR wild type and mutant NSCLC by degrading EGFR. Mechanistic studies disclosed that DPBA binds to the EGFR extracellular domain at sites differing from those of EGF and EGFR. DPBA did not induce EGFR dimerization, phosphorylation, and ubiquitination, but it significantly promoted EGFR degradation and repressed downstream survival pathways. Further analyses showed that DPBA induced clathrin-independent EGFR endocytosis mediated by flotillin-dependent lipid rafts and unaffected by EGFR TKIs. Activation of the early and late endosome markers rab5 and rab7 but not the recycling endosome marker rab11 was involved in DPBA-induced EGFR lysosomal degradation. The present study offers a new EGFR ligand for EGFR pharmacological degradation and proposes it as a potential treatment for EGFR-positive NSCLC, particularly NSCLC with innate or acquired EGFR TKI resistance. DPBA can also serve as a chemical probe in the studies on EGFR trafficking and degradation.

Natural tyrosine kinase inhibitors acting on the epidermal growth factor receptor: Their relevance for cancer therapy

Epidermal growth factor receptor (EGFR), also known as ErbB-1/HER-1, plays a key role in the regulation of the cell proliferation, migration, differentiation, and survival. Since the constitutive activation or overexpression of EGFR is nearly found in various cancers, the applications focused on EGFR are the most widely used in the clinical level, including the therapeutic drugs of targeting EGFR, monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs).Over the past decades, the compounds from natural sources have been a productive source of novel drugs, especially in both discovery and development of anti-tumor drugs by targeting the EGFR pathways as the TKIs. This work presents a review of the compounds from natural sources as potential EGFR-TKIs involved in the regulation of cancer. Moreover, high-throughput drug screening of EGFR-TKIs from the natural compounds has also been summarized.

BBB-penetrating codelivery liposomes treat brain metastasis of non-small cell lung cancer with EGFRT790M mutation

EGFR TKI therapy has become a first-line regimen for non-small cell lung cancer (NSCLC) patients with EGRF mutations. However, there are two big challenges against effective therapy--the secondary EGFR mutation-associated TKI resistance and brain metastasis (BMs) of lung cancer. The BMs is a major cause of death for advanced NSCLC patients, and the treatment of BMs with TKI resistance remains difficult.

Methods: Tumor-associated macrophages (TAM) is a promising drug target for inhibiting tumor growth, overcoming drug resistance, and anti-metastasis. TAM also plays an essential role in regulating tumor microenvironment. We developed a dual-targeting liposomal system with modification of anti-PD-L1 nanobody and transferrin receptor (TfR)-binding peptide T12 for codelivery of simvastatin/gefitinib to treat BMs of NSCLC.

Results: The dual-targeting liposomes could efficiently penetrate the blood-brain barrier (BBB) and enter the BMs, acting on TAM repolarization and reversal of EGFR^T790M-associated drug resistance. The treatment mechanisms were related to the elevating ROS and the suppression of the EGFR/Akt/Erk signaling pathway.

Conclusion: The dual-targeting liposomal codelivery system offers a promising strategy for treating the advanced EGFR^T790M NSCLC patients with BMs.

MsrA Suppresses Inflammatory Activation of Microglia and Oxidative Stress to Prevent Demyelination via Inhibition of the NOX2-MAPKs/NF-κB Signaling Pathway

Introduction

Demyelination causes neurological deficits involving visual, motor, sensory symptoms. Deregulation of several enzymes has been identified in demyelination, which holds potential for the development of treatment strategies for demyelination. However, the specific effect of methionine sulfoxide reductase A (MsrA) on demyelination remains unclear. Hence, this study aims to explore the effect of MsrA on oxidative stress and inflammatory response of microglia in demyelination.

Methods

Initially, we established a mouse model with demyelination induced by cuprizone and a cell model provoked by lipopolysaccharide (LPS). The expression of MsrA in wild-type (WT) and MsrA-knockout (MsrA^-/-) mice were determined by RT-qPCR and Western blot analysis. In order to further explore the function of MsrA on inflammatory response, and oxidative stress in demyelination, we detected the expression of microglia marker Iba1, inflammatory factors TNF-α and IL-1β and intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) activity, as well as expression of the NOX2-MAPKs/NF-κB signaling pathway-related genes in MsrA^-/- mice and LPS-induced microglia following different treatments.

Results

MsrA expression was downregulated in MsrA^-/- mice. MsrA silencing was shown to produce severely injured motor coordination, increased expressions of Iba1, TNF-α, IL-1β, ROS and NOX2, and extent of ERK, p38, IκBα, and p65 phosphorylation, but reduced SOD activity. Conjointly, our study suggests that Tat-MsrA fusion protein can prevent the cellular inflammatory response and subsequent demyelination through negative regulation of the NOX2-MAPKs/NF-κB signaling pathway.

Conclusion

Our data provide a profound insight on the role of endogenous antioxidative defense systems such as MsrA in controlling microglial function.

The synthesis and biological evaluation of sanguinarine derivatives as anti-non-small cell lung cancer agents

A novel series of sanguinarine (SA) derivatives were synthesized and evaluated as anti-non-small cell lung cancer (NSCLC) agents. The compounds inhibited A549 and H1975 NSCLC cells with IC₅₀ values of 0.96 - >30 μM and 0.79 - >30 μM, respectively. Compounds 8d-8j exhibited low micromolar inhibitory activity and indicated that the C6-position of SA was tolerated to be substituted by hydrophilic groups and CN. Further investigation of their mechanism of action showed that compound 8h induced apoptosis of A549 and H1975 cells by inhibiting the Akt signaling pathway and elevating the reactive oxygen species (ROS). This study provided a strategy for developing new anti-cancer agents.

APX-115A, a pan-NADPH Oxidase Inhibitor, Induces Caspase-dependent Cell Death by Suppressing NOX4-ROS Signaling in EBV-infected Retinal Epithelial Cells

PURPOSE

Epstein-Barr virus is a γ-herpes virus that infects primary B cells and can transform infected cells into immortalized lymphoblastoid cell lines (LCL). The role of EBV in malignancies such as Burkitt's lymphoma and nasopharyngeal carcinoma is well understood, however, its role in EBV-infected retinal cells remains poorly understood. Therefore, we investigated the effect of EBV on the growth of retinal cells.

METHODS

Previously, we established and reported a cell line model to address the relationship between EBV infection and retinal cell proliferation that used adult retinal pigment epithelium (ARPE-19) and EBV infection. To determine the effect of EBV on ARPE-19 cells, cell death was measured by propidium iodine/annexin V staining and reactive oxygen species (ROS) were measured by FACS, and protein expression was evaluated using western blot analysis. Also, downregulation of LMP1 and NADPH oxidase 4 (NOX4) expression was accomplished using siRNA technology.

RESULTS

We found that ROS were dramatically increased in EBV-infected ARPE19 cells (APRE19/EBV) relative to the parental cell line. Additionally, the expression level of NOX4, a main source of ROS, was upregulated by EBV infection. Interestingly, downregulation of LMP1, one of the EBV viral onco-proteins, completely decreased EBV-induced ROS accumulation and the upregulation of NOX4. Treatment with APX-115A, a pan-NOX inhibitor, induced apoptotic cell death of only the EBV-infected ARPE19 cells but not the parental cell line. Pretreatment with z-VAD, a pan-caspase inhibitor, inhibited NOX inhibitor-induced cell death in ARPE19/EBV cells. Furthermore, APX-115A-induced cell death mediated the activation of JNK and ERK. Finally, we confirmed the expression level of NOX4, and APX-115A induced cell death of EBV-infected human primary retina epithelial cells and the activation of JNK and ERK.

CONCLUSION

Taken together, these our results suggest that APX-115A could be a therapeutic agent for treating EBV-infected retinal cells or diseases by inhibiting LMP1-NOX4-ROS signaling.

EGFR Amplification Induces Increased DNA Damage Response and Renders Selective Sensitivity to Talazoparib (PARP Inhibitor) in Glioblastoma

PURPOSE

Exploration of novel strategies to extend the benefit of PARP inhibitors beyond BRCA-mutant cancers is of great interest in personalized medicine. Here, we identified EGFR amplification as a potential biomarker to predict sensitivity to PARP inhibition, providing selection for the glioblastoma (GBM) patient population who will benefit from PARP inhibition therapy.

EXPERIMENTAL DESIGN

Selective sensitivity to the PARP inhibitor talazoparib was screened and validated in two sets [test set (n = 14) and validation set (n = 13)] of well-characterized patient-derived glioma sphere-forming cells (GSC). FISH was used to detect EGFR copy number. DNA damage response following talazoparib treatment was evaluated by γH2AX and 53BP1 staining and neutral comet assay. PARP-DNA trapping was analyzed by subcellular fractionation. The selective monotherapy of talazoparib was confirmed using in vivo glioma models.

RESULTS

EGFR-amplified GSCs showed remarkable sensitivity to talazoparib treatment. EGFR amplification was associated with increased reactive oxygen species (ROS) and subsequent increased basal expression of DNA-repair pathways to counterelevated oxidative stress, and thus rendered vulnerability to PARP inhibition. Following talazoparib treatment, EGFR-amplified GSCs showed enhanced DNA damage and increased PARP-DNA trapping, which augmented the cytotoxicity. EGFR amplification-associated selective sensitivity was further supported by the in vivo experimental results showing that talazoparib significantly suppressed tumor growth in EGFR-amplified subcutaneous models but not in nonamplified models.

CONCLUSIONS

EGFR-amplified cells are highly sensitive to talazoparib. Our data provide insight into the potential of using EGFR amplification as a selection biomarker for the development of personalized therapy.

High levels of EGFR prevent sulforaphane-induced reactive oxygen species-mediated apoptosis in non-small-cell lung cancer cells

BACKGROUND

Sulforaphane (SFN) has been shown to induce the production of reactive oxygen species (ROS) and inhibit epidermal growth factor receptor (EGFR)-mediated signaling in non-small-cell lung cancer (NSCLC). NSCLC cells harboring constitutively active EGFR mutations are more sensitive to SFN treatment than cells with wild-type EGFR, but whether NSCLC cells with high levels of EGFR expression are more resistant or sensitive to SFN treatment is not known.

STUDY DESIGN

We employed a pair of cell lines, CL1-0 and CL1-5, which have the same genetic background but different levels of EGFR expression, to examine the effects of high EGFR level in the sensitivity to SFN.

METHODS

The effect of SFN on cell viability and tumorigenicity was examined by trypan blue dye-exclusion assay, clonogenic assays, flow cytometry, and immunoblotting in vitro as well as tumorigenicity study in vivo. ROS levels in cells were assessed by flow cytometry using the ROS-reactive fluorescent indicator CM-H2DCFDA. Knockdown of EGFR in CL1-5 cells was infected with an EGFR-targeting small hairpin (interfering) RNA (shRNA)-containing lentivirus.

RESULTS

We present evidence that cells with high-level EGFR expression (CL1-5) are more resistant to SFN treatment than those with low-level expression (CL1-0). SFN treatment produced a similar increase in ROS and caused arrest of a cell population at S-phase accompanied by the induction of γH2AX, a DNA damage-response marker, in both cell sublines. However, SFN induced apoptosis only in the high-EGFR-expressing CL1-0 subline. Pretreatment with the antioxidant N-acetyl-L-cysteine prevented SFN-induced apoptosis in CL1-0 cells and production of γH2AX in both CL1-0 and CL1-5 cells. shRNA-mediated knockdown of EGFR in CL1-5 cells rendered the cells susceptible to SFN-induced apoptosis.

CONCLUSION

The cellular effects produced by SFN in NSCLC cells are largely mediated by SFN-induced production of ROS. Cells with higher levels of EGFR were more resistant to SFN treatment and showed resistance to SFN-induced apoptosis, suggesting that high EGFR levels protect cells from SFN-induced apoptosis. Despite this, we found that SFN retained the ability to inhibit the growth of NSCLC tumors with high-level EGFR expression in vivo.

MicroRNA-421 confers paclitaxel resistance by binding to the KEAP1 3'UTR and predicts poor survival in non-small cell lung cancer

MicroRNAs regulate post-transcriptional gene expression and play important roles in multiple cellular processes. In this study, we found that miR-421 suppresses kelch-like ECH-associated protein 1(KEAP1) expression by targeting its 3'-untranslated region (3'UTR). A Q-PCR assay demonstrated that miR-421 is overexpressed in non-small cell lung cancer (NSCLC), especially in A549 cells. Consistently, the level of miR-421 was higher in clinical blood samples from lung cancer patients than in those from normal healthy donors, suggesting that miR-421 is an important lung cancer biomarker. Interestingly, overexpression of miR-421 reduced the level of KEAP1 expression, which further promoted lung cancer cell migration and invasion, as well as inhibited cell apoptosis both in vivo and in vitro. Furthermore, knockdown of miR-421 expression with an antisense morpholino oligonucleotide (AMO) increased ROS levels and treatment sensitivity to paclitaxel in vitro and in vivo, indicating that high miR-421 expression may at least partly account for paclitaxel tolerance in lung cancer patients. To find the upstream regulator of miR-421, one of the candidates, β-catenin, was knocked out via the CRISPR/Cas9 method in A549 cells. Our data showed that inhibiting β-catenin reduced miR-421 levels in A549 cells. In addition, β-catenin upregulation enhanced miR-421 expression, indicating that β-catenin regulates the expression of miR-421 in lung cancer. Taken together, our findings reveal the critical role of miR-421 in paclitaxel drug resistance and its upstream and downstream regulatory mechanisms. Therefore, miR-421 may serve as a potential molecular therapeutic target in lung cancer, and AMOs may be a potential treatment strategy.

Targeting Reactive Oxygen Species in Cancer via Chinese Herbal Medicine

Recently, reactive oxygen species (ROS), a class of highly bioactive molecules, have been extensively studied in cancers. Cancer cells typically exhibit higher levels of basal ROS than normal cells, primarily due to their increased metabolism, oncogene activation, and mitochondrial dysfunction. This moderate increase in ROS levels facilitates cancer initiation, development, and progression; however, excessive ROS concentrations can lead to various types of cell death. Therefore, therapeutic strategies that either increase intracellular ROS to toxic levels or, conversely, decrease the levels of ROS may be effective in treating cancers via ROS regulation. Chinese herbal medicine (CHM) is a major type of natural medicine and has greatly contributed to human health. CHMs have been increasingly used for adjuvant clinical treatment of tumors. Although their mechanism of action is unclear, CHMs can execute a variety of anticancer effects by regulating intracellular ROS. In this review, we summarize the dual roles of ROS in cancers, present a comprehensive analysis of and update the role of CHM—especially its active compounds and ingredients—in the prevention and treatment of cancers via ROS regulation and emphasize precautions and strategies for the use of CHM in future research and clinical trials.

Synthesis and anticancer activity of bis-benzo[d][1,3]dioxol-5-yl thiourea derivatives with molecular docking study

New thiourea derivatives incorporating two benzo[d][1,3]dioxol-5-yl moieties have been synthesized through the reaction of two molecules of benzo[d][1,3]dioxol-5-yl isothiocyanate with one molecule of various diamino derivatives. The synthesized compounds were examined for their cytotoxic effects using SRB assay on three cancer cell lines HepG2, HCT116 and MCF-7. Most of compounds showed significant antitumor activity and some compounds showed strong results greater than the reference drug. As example, IC₅₀ values of 1,1'-(1,4-phenylene)bis(3-(benzo[d][1,3]dioxol-5-yl)thiourea) 5 were 2.38 µM for HepG2, 1.54 µM for HCT116 and 4.52 µM for MCF7, while the IC₅₀ values of standard drug doxorubicin were 7.46, 8.29 and 4.56 µM, respectively. Interestingly, these compounds were non cytotoxic toward the tested normal cell line (IC₅₀ value > 150 µM). The anticancer mechanisms were studied via EGFR inhibition assessment, annexin V-FITC apoptosis assessment, cell cycle analysis and study the effect on mitochondrial apoptosis pathway proteins Bax and Bcl-2 as well as molecular docking studies.

Sanguinarine Induces Apoptosis Pathway in Multiple Myeloma Cell Lines via Inhibition of the JaK2/STAT3 Signaling

Sanguinarine (SNG), a benzophenanthridine alkaloid, has displayed various anticancer abilities in several vivo and in vitro studies. However, the anticancer potential of SNG is yet to be established in multiple myeloma (MM), a mostly incurable malignancy of plasma cells. In this study, we aimed to investigate the potential anti-proliferative and pro-apoptotic activities of SNG in a panel of MM cell lines (U266, IM9, MM1S, and RPMI-8226). SNG treatment of MM cells resulted in a dose-dependent decrease in cell viability through mitochondrial membrane potential loss and activation of caspase 3, 9, and cleavage of PARP. Pre-treatment of MM cells with a universal caspase inhibitor, Z-VAD-FMK, prevented SNG mediated loss of cell viability, apoptosis, and caspase activation, confirming that SNG-mediated apoptosis is caspase-dependent. The SNG-mediated apoptosis appears to be resulted from suppression of the constitutively active STAT3 with a concomitant increase in expression of protein tyrosine phosphatase (SHP-1). SNG treatment of MM cells leads to down-regulation of the anti-apoptotic proteins including cyclin D, Bcl-2, Bclxl, and XIAP. In addition, it also upregulates pro-apoptotic protein, Bax. SNG mediated cellular DNA damage in MM cell lines by induction of oxidative stress through the generation of reactive oxygen species and depletion of glutathione. Finally, the subtoxic concentration of SNG enhanced the cytotoxic effects of anticancer drugs bortezomib (BTZ) by suppressing the viability of MM cells via induction of caspase-mediated apoptosis. Altogether our findings demonstrate that SNG induces mitochondrial and caspase-dependent apoptosis, generates oxidative stress, and suppresses MM cell lines proliferation. In addition, co-treatment of MM cell lines with sub-toxic doses of SNG and BTZ potentiated the cytotoxic activity. These results would suggest that SNG could be developed into therapeutic agent either alone or in combination with other anticancer drugs in MM.

Critical role of H2O2 in mediating sanguinarine-induced apoptosis in prostate cancer cells via facilitating ceramide generation, ERK1/2 phosphorylation, and Par-4 cleavage

Natural products are a major source of potential anticancer agents, and in order to develop improved and more effective cancer treatments, there is an immense need in exploring and elucidating their mechanism of action. Sanguinarine (SNG), a quaternary benzophenanthridine alkaloid, has been shown to induce cytotoxicity in various human cancers and suppresses various pro-tumorigenic processes such as invasion, angiogenesis, and metastasis in different cancers. Lack of understanding the anticancer mechanism(s) of SNG has impeded the development of this molecule as a potential anticancer agent. Earlier, we have reported that SNG induces reactive oxygen species (ROS)-dependent ceramide (Cer) generation and Akt dephosphorylation, leading to the induction of apoptosis in human leukemic cells. In the present study, we demonstrate that SNG has potent anti-proliferative activity against prostate cancer cells. Our data suggest that SNG induces Cer generation via inhibiting acid ceramidase and glucosylceramide synthase, two important enzymes involved in Cer metabolism. Furthermore, we demonstrate that SNG induces ROS-depended extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation, and prostate apoptosis response-4 (Par-4) cleavage, leading to the induction of apoptosis in human prostate cancer cells. Overall, our findings provide molecular insight into the role of ROS signaling in the anticancer mechanism(s) of SNG. This may provide the basis for its use as a nontoxic and an effective therapeutic agent in the treatment of prostate cancer.

Thioredoxin Reductase as a Novel and Efficient Plasma Biomarker for the Detection of Non-Small Cell Lung Cancer: a Large-scale, Multicenter study

There is an increased demand for efficient biomarkers for the diagnosis of non-small cell lung cancer (NSCLC). This study aimed to evaluate plasma levels of TrxR activity in a large population to confirm its validity and efficacy in NSCLC diagnosis. Blood samples were obtained from 1922 participants (638 cases of NSCLC, 555 cases of benign lung diseases (BLDs) and 729 sex- and age-matched healthy controls). The plasma levels of TrxR activity in patients with NSCLC (15.66 ± 11.44 U/ml) were significantly higher (P < 0.01) than in patients with BLDs (6.27 ± 3.78 U/ml) or healthy controls (2.05 ± 1.86 U/ml). The critical value of plasma TrxR activity levels for diagnosis of NSCLC was set at 10.18 U/ml, with a sensitivity of 71.6% and a specificity of 91.9%. The combination of NSE, CEA, CA19-9, Cyfra21-1, and TrxR was more effective for NSCLC diagnosis (sensitivity and specificity in the training set: 85.6%, 90.2%; validation set: 86.2%, 92.4%) than was each biomarker individually (P < 0.001). TrxR can also efficiently distinguish the metastatic status of the tumor, and it can further differentiate between various histological differentiations. Together, plasma TrxR activity was identified as a convenient, non-invasive, and efficient biomarker for the diagnosis of NSCLCs, particularly for discriminating between metastatic and non-metastatic tumors, or for histologic differentiation.

The correlation of p22phox and chemosensitivity in EGFR-TKI resistant lung adenocarcinoma

Background

Enhancing the chemosensitivity in the patients with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) resistant lung adenocarcinoma (LUAD) is pivotal in achieving their successful therapeutic outcome. We aimed to explore the mechanisms regarding the development of therapeutic resistance to chemotherapy in EGFR-TKI resistant LUAD. Methods: Microarray analysis lead to potential involvement of p22^phox, which was abundantly expressed in the cell lines harboring EGFR-TKI resistance and chemoresistance, and was known to regulate several important chemoresistance-associated factors such as hypoxia inducible factor-1α (HIF-1α) and epithelial-mesenchymal transition (EMT). We compared the status of p22^phox with that of chemoresistance, HIF-1α expression and EMT in LUAD cell lines. We immunolocalized p22^phox in the specimens of lung cancer patients.

Results

p22^phox and HIF-1α mRNAs were significantly elevated in the cells harboring EMT and chemoresistance. p22^phox knockdown enhanced chemosensitivity and reduced the expression of HIF-1α and EMT-associated factors. HIF-1α knockdown enhanced the chemosensitivity, while HIF-1α transfection induced EMT and chemoresistance in these cell lines. All LUAD patients with T790M mutation were associated with abundant p22^phox immunoreactivity in carcinoma cells.

Conclusions

The analysis of p22^phox in lung carcinoma tissues could provide new insights into the selection of chemotherapy for the patients with EGFR-TKI resistant LUAD.

Carcinogenesis and Reactive Oxygen Species Signaling: Interaction of the NADPH Oxidase NOX1-5 and Superoxide Dismutase 1-3 Signal Transduction Pathways

SIGNIFICANCE

Reduction/oxidation (redox) balance could be defined as an even distribution of reduction and oxidation complementary processes and their reaction end products. There is a consensus that aberrant levels of reactive oxygen species (ROS), commonly observed in cancer, stimulate primary cell immortalization and progression of carcinogenesis. However, the mechanism how different ROS regulate redox balance is not completely understood. Recent Advances: In the current review, we have summarized the main signaling cascades inducing NADPH oxidase NOX1-5 and superoxide dismutase (SOD) 1-3 expression and their connection to cell proliferation, immortalization, transformation, and CD34+ cell differentiation in thyroid, colon, lung, breast, and hematological cancers.

CRITICAL ISSUES

Interestingly, many of the signaling pathways activating redox enzymes or mediating the effect of ROS are common, such as pathways initiated from G protein-coupled receptors and tyrosine kinase receptors involving protein kinase A, phospholipase C, calcium, and small GTPase signaling molecules.

FUTURE DIRECTIONS

The clarification of interaction of signal transduction pathways could explain how cells regulate redox balance and may even provide means to inhibit the accumulation of harmful levels of ROS in human pathologies.

The impact of PRDX4 and the EGFR mutation status on cellular proliferation in lung adenocarcinoma

Background: Oxidative stress plays key roles in the progression of lung adenocarcinoma. Recently, we reported that peroxiredoxin 4 (PRDX4), an antioxidant enzyme, can be a prognostic marker of lung adenocarcinoma (LUAD). In the present study, we aimed to further investigate the relationship among the PRDX4 expression, epidermal growth factor receptor (EGFR) mutations and cell proliferation in LUAD. Methods: The expression of PRDX4 was immunohistochemically analyzed and the EGFR mutation status was examined in 127 paraffin-embedded human surgical specimens from patients with stage I LUAD. The PRDX4 expression was considered to be high when >40% of the adenocarcinoma cells were positively stained. In vitro, using plasmid transfection methods, PRDX4 plasmid DNAs were transfected into human lung adenocarcinoma cell lines, A549 (EGFR-wild) or PC-9 (EGFR mutant). The viability of these cells was analyzed using a Cell Counting Kit-8 kit. Results: The number of cases with high PRDX4 expression levels among patients with LUAD with EGFR mutations was significantly larger than that in patients with EGFR wild-type. The combination of the PRDX4 expression level with the EGFR mutation status was closely associated with the prognosis of patients with stage I LUAD. Viability assays showed that the proliferation of A549 cells was significantly suppressed after PRDX4 plasmid transfection, while the overexpression of PRDX4 had no effect on the proliferation of EGFR-mutant PC-9 cells. Conclusions: The PRDX4 expression and EGFR mutation status were significantly associated with the prognosis of patients with stage I LUAD, and EGFR mutations affected the role of PRDX4 in the proliferation of LUAD cells.

Synthesis of Triazole-Substituted Quinazoline Hybrids for Anticancer Activity and a Lead Compound as the EGFR Blocker and ROS Inducer Agent

A series of triazole-substituted quinazoline hybrid compounds were designed and synthesized for anticancer activity targeting epidermal growth factor receptor (EGFR) tyrosine kinase. Most of the compounds showed moderate to good antiproliferative activity against four cancer cell lines (HepG2, HCT116, MCF-7, and PC-3). Compound 5b showed good antiproliferative activity (IC₅₀ = 20.71 μM) against MCF-7 cell lines. Molecular docking results showed that compound 5b formed hydrogen bond with Met 769 and Lys 721 and π-sulfur interaction with Met 742 of EGFR tyrosine kinase (PDB ID: 1M17). Compound 5b decreases the expression of EGFR and p-EGFR. It also induces apoptosis through reactive oxygen species generation, followed by the change in mitochondrial membrane potential.

Remodeling Tumor-Associated Macrophages and Neovascularization Overcomes EGFRT790M -Associated Drug Resistance by PD-L1 Nanobody-Mediated Codelivery

Precision medicine has made a significant breakthrough in the past decade. The most representative success is the molecular targeting therapy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) in non-small-cell lung cancer (NSCLC) with oncogenic drivers, approved by the US Food and Drug Administration (FDA) as first-line therapeutics for substituting chemotherapy. However, the rapidly developed TKI resistance invariably leads to unsustainable treatment. For example, gefitinib is the first choice for advanced NSCLC with EGFR mutation, but most patients would soon develop secondary EGFR^T790M mutation and acquire gefitinib resistance. TKI resistance is a severe emergency issue to be solved in NSCLC, but there are a few investigations of nanomedicine reported to address this pressing problem. To overcome EGFR^T790M -associated drug resistance, a novel delivery and therapeutic strategy is developed. A PD-L1 nanobody is identified, and first used as a targeting ligand for liposomal codelivery. It is found that simvastatin/gefitinib combination nanomedicine can remodel the tumor microenvironment (e.g., neovascularization regulation, M2-macrophage repolarization, and innate immunity), and display the effectiveness of reversing the gefitinib resistance and enhancing the EGFR^T790M -mutated NSCLC treatment outcomes. The novel simvastatin-based nanomedicine provides a clinically translatable strategy for tackling the major problem in NSCLC treatment and demonstrates the promise of an old drug for new application.