Autophagy In Non-small Cell Lung Cancer Cells Research Articles

Targeted inhibition of the PI3K/AKT/mTOR pathway by (+)-anthrabenzoxocinone induces cell cycle arrest, apoptosis, and autophagy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC), characterized by low survival rates and a high recurrence rate, is a major cause of cancer-related mortality. Aberrant activation of the PI3K/AKT/mTOR signaling pathway is a common driver of NSCLC. Within this study, the inhibitory activity of (+)-anthrabenzoxocinone ((+)-ABX), an oxygenated anthrabenzoxocinone compound derived from Streptomyces, against NSCLC is demonstrated for the first time both in vitro and in vivo. Mechanistically, it is confirmed that the PI3K/AKT/mTOR signaling pathway is targeted and suppressed by (+)-ABX, resulting in the induction of S and G2/M phase arrest, apoptosis, and autophagy in NSCLC cells. Additionally, the augmentation of intracellular ROS levels by (+)-ABX is revealed, further contributing to the inhibition of the signaling pathway and exerting inhibitory effects on tumor growth. The findings presented in this study suggest that (+)-ABX possesses the potential to serve as a lead compound for the treatment of NSCLC.Graphical abstract

FTO-mediated autophagy inhibition promotes non-small cell lung cancer progression by reducing the stability of SESN2 mRNA

The role of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) demethylase, in non-small cell lung cancer (NSCLC) has recently received widespread attention. However the underlying mechanisms of FTO-mediated autophagy regulation in NSCLC progression remain elusive. In this study, we found that FTO was significantly upregulated in NSCLC, and downregulation of FTO suppressed the growth, invasion and migration of NSCLC cells by inducing autophagy. FTO knockdown resulted in elevated m6A levels in NSCLC cells. Methylated RNA immunoprecipitation sequencing showed that sestrin 2 (SESN2) was involved in m6A regulation during autophagy in NSCLC cells. Interestingly, m6A modifications in exon 9 of SESN2 regulated its stability. FTO deficiency promoted the binding of insulin-like growth factor 2 mRNA-binding protein 1 to SESN2 mRNA, enhancing its stability and elevating its protein expression. FTO inhibited autophagic flux by downregulating SESN2, thereby promoting the growth, invasion and migration of NSCLC cells. Besides, the mechanism by which FTO blocked SESN2-mediated autophagy activation was associated with the AMPK-mTOR signaling pathway. Taken together, these findings uncover an essential role of the FTO–autophagy–SESN2 axis in NSCLC progression.

SLL-1A-16 suppresses proliferation and induces autophagy in non-small-cell lung cancer cells via the AKT/mTOR signaling pathway.

Non-small-cell lung cancer (NSCLC), which accounts for approximately eighty-five percent of lung cancer diagnoses worldwide, is a malignancy with high incidence and mortality rates. Among the various antitumor compounds, organic selenium-containing compounds have emerged as a promising class of therapeutic agents for cancer treatment. In the present study, SLL-1A-16, a new organoselenium small molecule, was discovered to exhibit antiproliferative activity against NSCLC both in vitro and in vivo. Treatment with SLL-1A-16 significantly inhibited NSCLC cell proliferation and induced apoptosis and autophagy. Mechanistically, SLL-1A-16 inhibited cell proliferation through G1-S phase arrest by reducing cyclin D1 and CDK4 expression. Additionally, SLL-1A-16 significantly induced apoptosis by upregulating cleaved caspase 3 and Bax expression, while downregulating Bcl-2 levels. Our study also demonstrated that SLL-1A-16 induced autophagy in NSCLC cells by inhibiting the Akt/mTOR pathway. Overall, our findings suggest that SLL-1A-16 could induce cell cycle arrest, apoptosis and autophagy in NSCLC cells by inhibiting the Akt/mTOR signaling pathways, providing a theoretical basis for the potential clinical application of SLL-1A-16 as a chemotherapeutic agent in NSCLC treatment.

Zinc finger protein 263 upregulates interleukin 33 and suppresses autophagy to accelerate the malignant progression of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a complex disease that remains a major public health concern worldwide. One promising avenue for NSCLC treatment is the targeting of transcription factors that regulate key pathways involved in cancer progression. In this study, we investigated the role of the transcription factor ZNF263 in NSCLC and its impact on the regulation of IL33, apoptosis, and autophagy. Levels of ZNF263 in tissues and cell lines were identified, after which the effects of its knockdown on cellular malignant behaviors, apoptosis and autophagy were assessed. Based on bioinformatics analysis, ZNF263 was found to bind to IL33 promoter, their mutual relationship was confirmed, as well as the role of IL33 in the regulation of ZNF263. The involvement of ZNF263 in the growth of xenograft tumors was assessed using tumor-bearing nude mouse models. Experimental results revealed that ZNF263 was upregulated in NSCLC tissue samples and cell lines. Its expression level is positively correlated with cellular malignant behaviors. We further demonstrated that ZNF263 upregulated IL33 expression, which, in turn, promoted the proliferation and migration, inhibited apoptosis and autophagy in NSCLC cells. Furthermore, ZNF263 knockdown reduced the growth of xenograft tumors in nude mice. This finding suggests that the inhibition of ZNF263 or IL33 may represent a novel therapeutic strategy for NSCLC. Importantly, our results highlight the crucial role of transcription factors in NSCLC and their potential as therapeutic targets.

PEDF inhibits non‑small cell lung cancer proliferation by suppressing autophagy through downregulation of AMPK‑ULK1 signaling.

Current investigations suggest that pigment epithelial‑derived factor (PEDF) can mediate the progression of non‑small cell lung cancer (NSCLC) by regulating autophagy. However, the underlying mechanisms associated with autophagy remain poorly elucidated. The aim of the present study was to investigate the association between the PEDF/adenosine 5'‑monophosphate‑activated protein kinase (AMPK)/Unc‑51 like autophagy‑activated kinase 1 (ULK1) pathway and autophagy in NSCLC. Intracellular autophagy was evaluated using indicators such as the expression and activation of microtubule‑associated protein light chain 3‑I (LC3‑I), LC3‑II and p62, as well as the distribution and number of autophagosomes observed by confocal microscopy. In addition, the activity and proliferative capacity of NSCLC cells under PEDF overexpression was also examined using Cell Counting Kit‑8 and lactate dehydrogenase (LDH) assays, and western blotting (WB) of related proteins. The results revealed that PEDF significantly inhibited NSCLC cell proliferation and viability, and increased LDH release and intercellular adhesion. Furthermore, PEDF suppressed the expression and activation of LC‑3 and reduced the number and distribution of autophagosomes. The PEDF‑induced inhibition of autophagy exhibited a direct association with the suppressed proliferation capacity and cell viability of NSCLC cells. The results of WB showed that NSCLC cells regulated autophagy through the AMPK/ULK1 signaling pathway. PEDF downregulated the AMPK/ULK1 signaling pathway, and AMPK or ULK1 overexpression markedly reduced the inhibitory effect of PEDF on autophagy. In conclusion, PEDF overexpression significantly inhibited the proliferative capacity and cell viability of NSCLC cells, as PEDF exerted an inhibitory function by regulating autophagy in NSCLC cells. Finally, it was demonstrated that autophagy may be suppressed by inhibiting the AMPK/ULK1 signaling pathway, thereby revealing a mechanism of lung cancer progression.

Biomimetic Red Blood Cell Membrane-Mediated Nanodrugs Loading Ursolic Acid for Targeting NSCLC Therapy.

Simple SummaryLung cancer is the second most common cancer after breast cancer. Non-small-cell lung cancer, which represents more than 85% of all lung cancer subtypes, is known for its tumor progression and metastasis, resulting in poor clinical outcomes. Conventional therapies for NSCLC, such as surgery, chemotherapy, and radiotherapy, always fail due to therapeutic resistance. In recent years, ursolic acid (UA), a natural pentacyclic triterpenoid compound, has been shown to be a promising antitumor drug by regulating multiple signaling pathways in cancers. Unfortunately, the poor water solubility, low bioavailability, and systemic toxicity of UA limit its clinical application. In this study, a biomimetic red blood cell membrane nanocarrier was developed to deliver UA to targeted tumor sites efficiently, and it inhibited tumor growth by inducing the apoptosis and autophagy of cancer cells both in vitro and in vivo.As one of the most common cancers worldwide, non-small-cell lung cancer (NSCLC) treatment always fails owing to the tumor microenvironment and resistance. UA, a traditional Chinese medicine, was reported to have antitumor potential in tumor models in vitro and in vivo, but showed impressive results in its potential application for poor water solubility. In this study, a novel biomimetic drug-delivery system based on UA-loaded nanoparticles (UaNPs) with a red blood cell membrane (RBCM) coating was developed. The RBCM-coated UANPs (UMNPs) exhibited improved water solubility, high stability, good biosafety, and efficient tumor accumulation. Importantly, the excellent antitumor efficiency of the UMNPs was confirmed both in vitro and in vivo in cancer models. In addition, we further investigated the antitumor mechanism of UMNPs. The results of Western blotting showed that UMNPs exerted an anticancer effect by inducing the apoptosis and autophagy of NSCLC cells, which makes it superior to free UA. In addition, body weight monitoring, hematoxylin and eosin (HE) analysis, and immunohistochemical (IHC) analysis showed no significant difference between UMNPs and the control group, indicating the safety of UMNPs. Altogether, the preparation of biomimetic UMNPs provides a promising strategy to improve outcomes in NSCLC.

Induction of Ferroptosis by Ophiopogonin-B Through Regulating the Gene Signature AURKA in NSCLC.

Ferroptosis is a new type of iron-dependent programmed cell death. In recent years, its role in the diagnosis and treatment of multiple tumors, including non-small cell lung cancer (NSCLC), has been continuously observed. The relationship between the ferroptosis-related genes and the prognosis of patients with NSCLC needs to be clarified. In this study, The Cancer Genome Atlas (TCGA) and the Gene Expression Synthesis database (Gene Expression Omnibus, GEO) were used to build a model of ferroptosis-related differentially expressed genes (DEGs). A total of 101 ferroptosis-related DEGs were screened using R language, and a 12-gene signature was finally established through univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO)-penalized Cox regression analysis. According to the risk scores, the patients were divided into a high-risk or a low-risk group, with patients in the low-risk group showing better prognosis. AURKA, one of the genes in the 12-gene signature, was found to be highly expressed in tumors. In addition, further study verified AURKA to be a negative regulator of ferroptosis in NSCLC cells. Ophiopogonin B (OP-B) had been reported to induce apoptosis, mitotic catastrophe, and autophagy in NSCLC cells. Herein, proteomic sequencing analysis and OP-B administration revealed the upregulation of AURKA and the downregulation of PHKG2 and SLC7A5 in the 12-gene signature, indicating that OP-B induced ferroptosis in NSCLC. Determination of the concentrations of malondialdehyde (MDA), glutathione (GSH), and intracellular iron and the mitochondrial membrane potential (MMP) confirmed the induction of ferroptosis by OP-B in vitro. Furthermore, transmission electron microscopy (TEM) examination of lung cancer xenotransplantation in nude mice confirmed that OP-B induced ferroptosis in vivo. Further study of the molecular mechanism showed that the ferroptosis effect caused by OP-B can be partially reversed by the overexpression of AURKA. Overall, our study established a new ferroptosis-related risk prediction model for the prognosis of patients with NSCLC, revealed the enrichment pathways of ferroptosis in NSCLC, and discovered the negative regulation of AURKA in ferroptosis. On this basis, we demonstrated that OP-B can induce ferroptosis in NSCLC and clarified the specific molecular mechanism of OP-B inducing ferroptosis by regulating the expression of AURKA.

Combining EGFR-TKI With SAHA Overcomes EGFR-TKI-Acquired Resistance by Reducing the Protective Autophagy in Non-Small Cell Lung Cancer.

Nowadays, lung cancer has the highest mortality worldwide. The emergence of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has greatly improved the survival of patients with non-small cell lung cancer (NSCLC) having EGFR-TKI-sensitive mutations. Unfortunately, acquired resistance happens for most patients. In the present research, we found that EGFR-TKIs (such as gefitinib and osimertinib) can induce autophagy in NSCLC cell lines. Compared with parental sensitive cells, drug-resistant cells have higher autophagy activity. The use of an autophagy inhibitor could enhance the toxicity of gefitinib and osimertinib, which indicates that the enhancement of protective autophagy might be one of the mechanisms of EGFR-TKI resistance in NSCLC. In addition, increased autophagy activity is associated with decreased enhancer of zeste homolog 2 (EZH2) expression. Knockdown of EZH2 or EZH2 inhibitor treatment could lead to increased autophagy in NSCLC cells, indicating that EZH2 is a negative regulator of autophagy. We revealed that the increase in autophagy caused by the reduction of EZH2 was reversed in vitro and in vivo when combining gefitinib or osimertinib with suberoylanilide hydroxamic acid (SAHA), a broad-spectrum histone deacetylase inhibitor (HDACi). In conclusion, our results indicated that the combination of EGFR-TKIs and SAHA may be a new strategy to overcome EGFR-TKIs acquired resistance.

Circ_0020123 regulates autophagy, glycolysis, and malignancy by upregulating IRF4 through eliminating miR-193a-3p-mediated suppression of IRF4 in non-small cell lung cancer.

Circular RNA is related to the tumorigenesis of various cancers. Circular RNA hsa_circ_0020123 (circ_0020123) has been uncovered to promote non-small cell lung cancer (NSCLC) progression. However, the regulatory mechanism of circ_0020123 in NSCLC is unclear. The quantitative real-time polymerase chain reaction was employed to detect the levels of circ_0020123, microRNA (miR)-193a-3p, and IRF4 interferon regulatory factor 4 (IRF4) in NSCLC tissues and cells. Loss-of-function experiments were performed to analyze the impacts of circ_0020123 silencing on NSCLC cell malignancy, autophagy, and glycolysis. Protein levels were detected using western blotting. The regulatory mechanism of circ_0020123 was analyzed by bioinformatics analysis and validated by the dual-luciferase reporter, RNA immunoprecipitation assay, and RNA pull-down assay. Xenograft assay was performed to verify the biological function of circ_0020123. We observed an overt elevation in circ_0020123 expression in NSCLC samples and cells, and NSCLC patients with high circ_0020123 expression had a poor prognosis. Circ_0020123 knockdown constrained xenograft tumor growth in vivo and curbed cell proliferation, migration, and glycolysis, and accelerated cell apoptosis and autophagy in NSCLC cells in vitro. Circ_0020123 could absorb miR-193a-3p to regulate IRF4 expression. miR-193a-3p silencing overturned circ_0020123 knockdown-mediated impacts on NSCLC cell malignancy, autophagy, and glycolysis. And IRF4 overexpression reversed miR-193a-3p mimic-mediated effects on NSCLC cell malignancy, autophagy, and glycolysis. Circ_0020123 promoted glycolysis and tumor growth by upregulating IRF4 through sequestering miR-193a-3p in NSCLC, offering a novel mechanism by which circ_0020123 is responsible for the malignancy, autophagy, and glycolysis of NSCLC cells.

Sertaconazole provokes proapoptotic autophagy via stabilizing TRADD in nonsmall cell lung cancer cells.

Nonsmall cell lung cancer (NSCLC) is one of the most commonly diagnosed and lethal cancers characterized by relatively low overall cure and poor survival rates with great challenge for consistent effective clinical treatment. Here we demonstrated that the antifungal sertaconazole displays potent anti‐NSCLC effect by promoting apoptosis in vitro and in vivo. Further studies found that sertaconazole induces complete autophagic flux, which contributes to sertaconazole‐induced apoptosis and subsequent growth suppression in NSCLC cells. Further studies demonstrated that sertaconazole provokes TNF receptor type 1 associated death domain protein (TRADD) expression via stabilizing it from ubiquitination‐mediated degradation, which results in Akt dephosphorylation and thereby triggers proapoptotic autophagy in NSCLC cells. Moreover, we found that TRADD suppression reverses sertaconazole‐induced proapoptotic autophagy and relieves growth suppression, indicating the vital role of TRADD‐regulated proapoptotic autophagy in the anti‐NSCLC activity of sertaconazole. In summary, our findings suggest that sertaconazole could be a highly promising anti‐NSCLC drug by triggering proapoptotic autophagy via stabilizing TRADD, which may provide a new potential therapeutic option for patients with NSCLC.

Mufangji Decoction and Its Active Ingredient Patchouli Alcohol Inhibit Tumor Growth through Regulating Akt/mTOR-Mediated Autophagy in Nonsmall-Cell Lung Cancer.

Background Nonsmall-cell lung cancer (NSCLC) is the main type of lung cancer, whose morbidity and mortality rank first among malignant tumors. More than 70% of NSCLC patients are diagnosed at locally advanced or advanced stage, missing the best operation period. Chemotherapy and targeted therapy are important means for the treatment of advanced NSCLC, but various side effects seriously affect the curative effect and the life quality of NSCLC patients. Our previous clinical practice has shown that Mufangji Decoction, a classic traditional Chinese medicine, has a significant curative effect in the treatment of NSCLC, but the specific mechanism is not clear. This study intends to explore the potential mechanism of Mufangji Decoction and its active ingredient patchouli alcohol against NSCLC and to provide a scientific basis for the prevention and treatment of NSCLC by traditional Chinese medicine. Methods The in vivo and in vitro experiments were performed to evaluate the antitumor effects and investigate the underlying mechanism of Mufangji Decoction and its active ingredient patchouli alcohol. Network pharmacology was applied to analyze the effective ingredients and potential targets or signaling pathways of Mufangji Decoction. Results Our current study shows that Mufangji Decoction can effectively inhibit the growth of subcutaneous transplantation of NSCLC. The following network pharmacological analysis and in vivo experiment suggest that patchouli alcohol is one of the main active ingredients of Mufangji Decoction and exerts antitumor effects. Further mechanism investigation reveals that the antitumor effect of patchouli alcohol is related to the induction of Akt/mTOR signaling pathway-mediated autophagy in NSCLC cells. Conclusion Mufangji Decoction and its active ingredient patchouli alcohol might exert their antitumor effects in NSCLC partly through regulating Akt/mTOR-mediated autophagy, providing the evidence that traditional Chinese medicine might be a key approach for NSCLC treatment via targeting the Akt/mTOR signal axis.

Pyoluteorin Induces Apoptosis and Autophagy in NSCLC Cells.

Pyoluteorin is a natural occurring antibiotic and its anti-tumor activity has rarely been reported. This study aims to investigate the anti-tumor effects of pyoluteorin on human non-small cell lung cancer (NSCLC) cells. The cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was determined through caspase3 activity assay and immunoblotting. Autophagy was measured by transmission electron microscope (TEM) and immunostaining. The autophagy-related proteins were detected through immunoblotting. We found that pyoluteorin showed significant anti-tumor effects on human NSCLC cell lines H1299 (IC50 = 1.57 µM) and H2030 (IC50 = 1.94 µM). Moreover, pyoluteorin could induce apoptosis and autophagy as evidence by the upregulation of caspase3 activity, the accumulation of LC3 and expression of apoptosis or autophagy related proteins. In addition, pyoluteorin induced autophagy through c-Jun N-terminal kinase/B-cell lymphoma-2 (JNK/Bcl-2) signal pathway. Blocking JNK/Bcl-2 pathway significantly attenuated pyoluteorin-induced autophagy. Moreover, inhibition of autophagy by 3-methyladenine (3-MA) or Beclin1 knockout greatly promoted pyoluteorin-induced apoptosis and cell death. Our results showed that pyoluteorin could induce both apoptosis and autophagy in human NSCLC cells. Combination of pyoluteorin with autophagy inhibitior significantly promoted pyoluteorin-induced apoptosis and may be a potential anticancer strategy in the NSCLC therapy.

Combination Treatment With Inhibitors of ERK and Autophagy Enhances Antitumor Activity of Betulinic Acid in Non-small-Cell Lung Cancer In Vivo and In Vitro.

Aberrant activation of the Ras–ERK signaling pathway drives many important cancer phenotypes, and several inhibitors targeting such pathways are under investigation and/or approved by the FDA as single- or multi-agent therapy for patients with melanoma and non–small-cell lung cancer (NSCLC). Here, we show that betulinic acid (BA), a natural pentacyclic triterpenoid, inhibits cell proliferation, and induces apoptosis and protective autophagy in NSCLC cells. Thus, the cancer cell killing activity of BA is enhanced by autophagy inhibition. Mitogen-activated protein kinases, and especially ERK that facilitates cancer cell survival, are also activated by BA treatment. As such, in the presence of ERK inhibitors (ERKi), lung cancer cells are much more sensitive to BA. However, the dual treatment of BA and ERKi results in increased protective autophagy and AKT phosphorylation. Accordingly, inhibition of AKT has a highly synergistic anticancer effect with co-treatment of BA and ERKi. Notably, autophagy inhibition by hydroxychloroquine (HCQ) increases the response of lung cancer cells to BA in combination with ERKi. In vivo, the three-drug combination (BA, ERKi, and HCQ), resulted in superior therapeutic efficacy than single or dual treatments in the xenograft mouse model. Thus, our study provides a combined therapy strategy that is a highly effective treatment for patients with NSCLC.

Circular RNA circ_0003028 contributes to tumorigenesis by regulating GOT2 via miR-1298-5p in non-small cell lung cancer

ABSTRACT Non-small cell lung cancer (NSCLC) is a common malignant tumor, with high morbidity and mortality. Circular RNA (circRNA) circ_0003028 was reported to be upregulated in NSCLC. This study is designed to explore the role and mechanism of circ_0003028 on NSCLC progression. In this work, circ_0003028, microRNA-1298-5p (miR-1298-5p), and glutamic oxaloacetic transaminase 2 (GOT2) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The localization of circ_0003028 was analyzed by subcellular fractionation assay. Cell proliferation, colony number, cell cycle progression, apoptosis, migration, invasion, and angiogenesis were measured by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, transwell, and tube formation assays. Protein levels of Beclin1, light chain 3 (LC3)-II/LC3-I, GOT2, proliferating cell nuclear antigen (PCNA) were examined by western blot assay. The binding relationship between miR-1298-5p and circ_0003028 or GOT2 was predicted by circular RNA Interactome or starbase and then verified by dual-luciferase reporter, RNA Immunoprecipitation (RIP), and RNA pull-down assays. The biological role of circ_0003028 on NSCLC tumor growth was examined by the xenograft tumor model in vivo. We reported that circ_0003028 and GOT2 were upregulated, and miR-1298-5p was decreased in NSCLC tissues and cells. Moreover, circ_0003028 knockdown curbed cell proliferative ability, migration, invasion, angiogenesis, and facilitate apoptosis and autophagy in NSCLC cells in vitro. Mechanical analysis discovered that circ_0003028 regulated GOT2 expression by sponging miR-1298-5p. Circ_0003028 silencing hindered the cell growth of NSCLC in vivo. Taken together, circ_0003028 knockdown could suppress NSCLC progression partly by regulating the miR-1298-5p/GOT2 axis, providing an underlying therapeutic target for NSCLC.

SKIL facilitates tumorigenesis and immune escape of NSCLC via upregulating TAZ/autophagy axis

Immune escape is an important mechanism in tumorigenesis. The aim of this study was to investigate roles of SKIL in tumorigenesis and immune escape of non-small-cell lung cancer (NSCLC). SKIL expression levels in NSCLC cell line, clinical sample, and adjacent normal tissue were measured by quantitative PCR, western blot, or immunohistochemistry. Lentivirus was used to overexpress/silence SKIL or TAZ expression. Malignant phenotypes of NSCLC cells were evaluated by colony formation, transwell, and MTT assays, and in xenograft mice model. Syngeneic mice model and flow cytometry were used to evaluate T cell infiltration. Quantitative PCR and western blot were applied to evaluate relevant mRNA and protein levels, respectively. Co-immunoprecipitation was applied to unveil the interaction between SKIL and TAZ. SKIL expression was higher in NSCLC tissue compared to adjacent normal tissue. Silencing of SKIL inhibited malignant phenotypes of NSCLC cells and promoted T cell infiltration. SKIL-knockdown inhibited autophagy and activated the STING pathway in NSCLC cells through down-regulation of TAZ. Silencing of TAZ cancelled the effects of SKIL overexpression on malignant phenotypes and autophagy of NSCLC cells. Inhibition of autophagy reversed the effects of SKIL/TAZ overexpression on the STING pathway. In conclusion, SKIL promoted tumorigenesis and immune escape of NSCLC cells through upregulation of TAZ/autophagy axis and inhibition on downstream STING pathway.

Autophagy inhibition enhances the inhibitoryeffects of ursolic acid on lung cancer cells.

The aim of the present study was to identify natural compounds that bear significant anti-tumor activity. Thus, the effects of 63 small molecules that were isolated from traditional Chinese medicinal herbs on A549 human non-small cell lung cancer (NSCLC) and MCF-7 breast cancer cells were examined. It was found that ursolic acid (UA), a natural pentacyclic triterpenoid, exerted significant inhibitory effect on these cells. Further experiments revealed that UA inhibited the proliferation of various lung cancer cells, including the NSCLC cells, H460, H1975, A549, H1299 and H520, the human small cell lung cancer (SCLC) cells, H82 and H446, and murine Lewis lung carcinoma (LLC) cells. UA induced the apoptosis and autophagy of NSCLC cells. The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway, but not the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway contributed to the UA-induced autophagy of NSCLC cells. Moreover, the inhibition of autophagy by chloroquine (CQ) or siRNA for autophagy-related gene 5 (ATG5) enhanced the UA-induced inhibition of cell proliferation and promotion of apoptosis, indicating that UA-induced autophagy is a pro-survival mechanism in NSCLC cells. On the whole, these findings suggest that combination treatment with autophagy inhibitors may be a novel strategy with which enhance the antitumor activity of UA in lung cancer.

LncRNA KTN1-AS1 promotes the progression of non-small cell lung cancer via sponging of miR-130a-5p and activation of PDPK1.

Non-small cell lung cancer (NSCLC) is the major cause of cancer-associated death worldwide, but its underlying mechanisms remain to be fully elucidated. Long noncoding RNAs (lncRNAs) are known to play an important role in the aberrant regulation of gene expression in many cancers, including NSCLC. Here, we investigated the involvement of the lncRNA KTN1-AS1 in NSCLC. We found that KTN1-AS1 expression was upregulated in NSCLC tissue and was positively associated with poor prognosis. KTN1-AS1 knockdown inhibited cell growth and proliferation, increased apoptosis, and modulated the expression of cell cycle- and apoptosis-related proteins (cyclin A1, cyclin-dependent kinase 2, Bcl2, and Bax) in NSCLC cell lines and tumour xenografts in nude mice. KTN1-AS1 bound to and directly regulated the expression of miR-130a-5p. Notably, miR-130a-5p overexpression suppressed NSCLC cell proliferation and increased apoptosis in vitro and in vivo, and this effect was reversed by KTN1-AS1 overexpression. Finally, we showed that KTN1-AS1 modulated the expression of 3-phosphoinositide-dependent protein kinase 1 (PDPK1), a miR-130a-5p target and key regulator of autophagy in NSCLC cells. Taken together, our results suggest that the KTN1-AS1/miR-130a-5p/PDPK1 pathway may be a potential therapeutic target for NSCLC.

Induction of cytoprotective autophagy by morusin via AMP-activated protein kinase activation in human non-small cell lung cancer cells.

BACKGROUND/OBJECTIVESMorusin, a marker component of Morus alba L., possesses anti-cancer activity. The objective of this study was to determine autophagy-inducing effect of morusin in non-small cell lung cancer (NSCLC) cells and investigate the underlying mechanism.SUBJECTS/METHODSAutophagy induction and the expression of autophagy-related proteins were analyzed by LC3 immunofluorescence and western blot, respectively. The role of autophagy and AMP-activated protein kinase (AMPK) was determined by treating NSCLC cells with bafilomycin A1, an autophagy inhibitor, and compound C, an AMPK inhibitor. Cytotoxicity and apoptosis induction were determined by MTT assay, trypan blue exclusion assay, annexin V-propidium iodide (PI) double staining assay, and cell cycle analysis.RESULTSMorusin increased the formation of LC3 puncta in the cytoplasm and upregulated the expression of autophagy-related 5 (Atg5), Atg12, beclin-1, and LC3II in NSCLC cells, demonstrating that morusin could induce autophagy. Treatment with bafilomycin A1 markedly reduced cell viability but increased proportions of sub-G1 phase cells and annexin V-positive cells in H460 cells. These results indicate that morusin can trigger autophagy in NSCLC cells as a defense mechanism against morusin-induced apoptosis. Furthermore, we found that AMPK and its downstream acetyl-CoA carboxylase (ACC) were phosphorylated, while mammalian target of rapamycin (mTOR) and its downstream p70S6 kinase (p70S6K) were dephosphorylated by morusin. Morusin-induced apoptosis was significantly increased by treatment with compound C in H460 cells. These results suggest that morusin-induced AMPK activation could protect NSCLC cells from apoptosis probably by inducing autophagy.CONCLUSIONSOur findings suggest that combination treatment with morusin and autophagy inhibitor or AMPK inhibitor might enhance the clinical efficacy of morusin for NSCLC.

Assessing methods to quantitatively validate TGFβ-dependent autophagy.

ABSTRACTTransforming growth factor beta (TGFβ) promotes tumorigenesis by suppressing immune surveillance and inducing epithelial to mesenchymal transition (EMT). TGFβ may augment tumorigenesis by activating autophagy, which protects cancer cells from chemotherapy and promotes invasive and anti-apoptotic properties. Here, we assess how TGFβ1 modulates autophagy related (ATG) gene expression and ATG protein levels. We also assessed microtubule-associated protein light chain 3 (LC3) lipidation, LC3 puncta formation and autophagosome-lysosome co-localization in non-small cell lung cancer (NSCLC) cell lines. These experimental approaches were validated using pharmacological autophagy inhibitors (chloroquine and spautin-1) and an autophagy activator (MG132). We found that TGFβ1, chloroquine and MG132 had little effect on ATG protein levels but increased LC3 lipidation, LC3 puncta formation and autophagosome-lysosome co-localization. Since similar outcomes were observed using chloroquine and MG132, we concluded that several techniques employed to assess TGFβ-dependent autophagy may not differentiate between the activation of autophagy versus lysosomal inhibition. Thus, NSCLC cell lines stably expressing a GFP-LC3-RFP-LC3ΔG autophagic flux probe were used to assess TGFβ-mediated autophagy. Using this approach, we observed that TGFβ, MG132 and serum starvation increased autophagic flux, whereas chloroquine and spautin-1 decreased autophagic flux. Finally, we demonstrated that ATG5 and ATG7 are critical for TGFβ-dependent autophagy in NSCLC cells. The application of this model will fuel future experiments to characterize TGFβ-dependent autophagy, which is necessary to understand the molecular processes that link, TGFβ, autophagy and tumorigenesis.

Sotetsuflavone Induces Autophagy in Non-Small Cell Lung Cancer Through Blocking PI3K/Akt/mTOR Signaling Pathway in Vivo and in Vitro.

Non-small cell lung cancer (NSCLC) is a globally scaled disease with a high incidence and high associated mortality rate. Autophagy is one of the important physiological activities that helps to control cell survival, influences the dynamics of cell death, and which plays a crucial role in the pathophysiology of NSCLC. Sotetsuflavone is a naturally derived and occurring flavonoid, and previous studies have demonstrated that sotetsuflavone possesses potential anti-cancer activities. However, whether or not sotetsuflavone induces autophagy, as well as has effects and influences cell death in NSCLC cells remains unclear. Thus, in our study, we examined and elucidated the roles and underlying mechanisms of sotetsuflavone upon the dynamics of autophagy in NSCLC in vivo and in vitro. The results indicated that sotetsuflavone was able to inhibit proliferation, migration, and invasion of NSCLC cells. Mechanistically, sotetsuflavone was able to induce apoptosis by increasing the levels of expression of cytochrome C, cleaved-caspase 3, cleaved-caspase 9, and Bax, and contrastingly decreased levels of expression of Bcl-2. In addition, we also found that decreased levels of expression of cyclin D1 and CDK4 caused arrest of the G0/G1 phases of the cell cycle. Furthermore, we also found that sotetsuflavone could induce autophagy which in turn can play a cytoprotective effect on apoptosis in NSCLC. Sotetsuflavone-induced autophagy appeared related to the blocking of the PI3K/Akt/mTOR pathway. Our in vivo study demonstrated that sotetsuflavone significantly inhibited the growth of xenograft model inoculated A549 tumor with high a degree of safety. Taken together, these findings suggest that sotetsuflavone induces autophagy in NSCLC cells through its effects upon blocking of the PI3K/Akt/mTOR signaling pathways. Our study may provide a theoretical basis for future clinical applications of sotetsuflavone and its use as a chemotherapeutic agent for treatment of NSCLC.