Apoptosis In NSCLC Cells Research Articles

SNHG14 silencing suppresses the progression and promotes cisplatin sensitivity in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) small nucleolar RNA host gene 14 (SNHG14) has been identified as an oncogene involved in the progression of various human cancers. Nevertheless, the functional role and molecular mechanism of SNHG14 on NSCLC remain largely elusive. qRT-PCR assay was performed to detect the levels of SNHG14, miR-34a and high mobility group box 1 (HMGB1) mRNA. HMGB1 protein level was assessed by western blot analysis. CCK-8 assay was used to determine the IC50 value of cisplatin (CDDP), and transwell assays were employed to detect cell migration and invasion abilities. Cell apoptosis was determined by flow cytometric analysis. Dual-luciferase reporter assay, RNA immuoprecipitation assay and RNA pull-down assay were performed to confirm the interaction between SNHG14 and miR-34a, or miR-34a and HMGB1. Our data demonstrated that SNHG14 was upregulated in NSCLC cells, and SNHG14 silencing repressed the migration, invasion while accelerated the apoptosis of NSCLC cells. Moreover, we manifested that SNHG14 silencing promoted NSCLC cell sensitivity to CDDP. SNHG14 repressed miR-34a expression by binding to miR-34a. Additionally, SNHG14 regulated HMGB1 expression by sponging miR-34a. SNHG14 silencing exerted its regulatory effect by miR-34a and HMGB1 mediated the regulatory effect of miR-34a on NSCLC cells. In conclusion, SNHG14 silencing suppressed NSCLC progression at least partly by miR-34a/HMGB1 axis in vitroand promoted NSCLC cell sensitivity to CDDP, highlighting that SNHG14 might be a potential target for NSCLC therapy.

LncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) Promotes Proliferation and Inhibits Apoptosis in Non-Small Cell Lung Cancer Cells by Regulating the miR-641/CDK6 Axis.

BackgroundThe lncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) gene has been reported as a potential oncogene in NSCLC. Nevertheless, the molecular mechanism of CRNDE in NSCLC progression remains largely unknown.Material/MethodsqRT-PCR assay was performed to detect the expression levels of CRNDE, miR-641, and cyclin-dependent kinase 6 (CDK6) in NSCLC. Western blot assay was employed to assess CDK6 protein level in treated NSCLC cells. si-CRNDE#1, si-CRNDE#2, miR-641 mimics, miR-641 inhibitors, or Vector-CDK6 were transfected into NSCLC cells to change the expression levels of CRNDE, miR-641, or CDK6. Dual-luciferase reporter assay was performed to validate the direct interrelated miRNA of CRNDE and the potential target of miR-641. MTT and flow cytometry assays were performed to assess the capacities of cell proliferation and apoptosis, respectively.ResultsCRNDE level was upregulated in NSCLC, and its knockdown suppressed NSCLC cells proliferation and enhanced apoptosis, whereas miR-641 antagonized the regulatory effect of CRNDE knockdown by directly binding to CRNDE. Moreover, CDK6 was a target of miR-641 and miR-641 exerted anti-proliferation and pro-apoptosis effects through CDK6.ConclusionsCRNDE promoted proliferation and inhibited apoptosis of NSCLC cells at least in part by regulating the miR-641/CDK6 axis, suggesting that CRNDE is a potential therapeutic target for NSCLC treatment.

Expression and significance of LncRNA MNX1-AS1 in non-small cell lung cancer.

Objective: To investigate the expression of LncRNA MNX1-AS1 in NSCLC and its effect on NSCLC cell lines.Methods: In this experiment, the expression of LncRNA MNX1-AS1 was detected by qRT-PCR in 116 NSCLC samples, and the correlation between MNX1-AS1 and NSCLC patients was further analyzed by chi-square test. The prognostic value of MNX1-AS1 was assessed by Kaplan-Meier survival curve. The expression of MNX1-AS1 in NSCLC cell line A549 was knocked down, and the effects of MNX1-AS1 on proliferation, apoptosis, migration and invasion of NSCLC cells were evaluated.Results: Compared with normal lung tissue, the expression of MNX1-AS1 was significantly increased in lung cancer tissues (p<0.05). The expression level of MNX1-AS1 in NSCLC cell line A549 was significantly higher than that in human normal lung epithelial cell line Beas-2B (p<0.05). MNX1-AS1 expression was significantly associated with TNM stage and lymph node metastasis (p<0.05). Kaplan-Meier survival curve analysis showed that high expression of MNX1-AS1 was associated with a poor prognosis in NSCLC. In addition, knockdown of MNX1-AS1 inhibited proliferation, migration and invasion of the NSCLC cell line A549 and promoted apoptosis.Conclusion: The up-regulation of LncRNA MNX1-AS1 is associated with the progression and prognosis of NSCLC. Knockdown of LncRNA MNX1-AS1 inhibits proliferation, migration and invasion of NSCLC cells and promotes apoptosis.

Overexpression of miR-758 inhibited proliferation, migration, invasion, and promoted apoptosis of non-small cell lung cancer cells by negatively regulating HMGB.

Non-small cell lung cancer (NSCLC) is one of the most fatal types of cancer with significant mortality and morbidity worldwide. MicroRNAs (miRs) have been confirmed to have positive functions in NSCLC. In the present study, we try to explore the role of miR-758 in proliferation, migration, invasion, and apoptosis of NSCLC cells by regulating high-mobility group box (HMGB) 3 (HMGB3.) NSCLC and adjacent tissues were collected. Reverse transcription quantitative PCR (RT-qPCR) was employed to detect expression of miR-758 and HMGB3 in NSCLC and adjacent tissues, in BEAS-2B cells and NSCLC cell lines. The targetted relationship between miR-758 and HMGB3 was identified by dual luciferase reporter gene assay. The effects of miR-758 on proliferation, migration, invasion, cell cycle, and apoptosis of A549 cells. MiR-758 expression was lower in NSCLC tissues, which was opposite to HMGB3 expression. The results also demonstrated that miR-758 can target HMGB3. The cells transfected with miR-758 mimic had decreased HMGB3 expression, proliferation, migration, and invasion, with more arrested cells in G1 phase and increased apoptosis. Our results supported that the overexpression of miR-758 inhibits proliferation, migration, and invasion, and promotes apoptosis of NSCLC cells by negative regulating HMGB2. The present study may provide a novel target for NSCLC treatment.

Sensitivity to splicing modulation of BCL2 family genes defines cancer therapeutic strategies for splicing modulators

Dysregulation of RNA splicing by spliceosome mutations or in cancer genes is increasingly recognized as a hallmark of cancer. Small molecule splicing modulators have been introduced into clinical trials to treat solid tumors or leukemia bearing recurrent spliceosome mutations. Nevertheless, further investigation of the molecular mechanisms that may enlighten therapeutic strategies for splicing modulators is highly desired. Here, using unbiased functional approaches, we report that the sensitivity to splicing modulation of the anti-apoptotic BCL2 family genes is a key mechanism underlying preferential cytotoxicity induced by the SF3b-targeting splicing modulator E7107. While BCL2A1, BCL2L2 and MCL1 are prone to splicing perturbation, BCL2L1 exhibits resistance to E7107-induced splicing modulation. Consequently, E7107 selectively induces apoptosis in BCL2A1-dependent melanoma cells and MCL1-dependent NSCLC cells. Furthermore, combination of BCLxL (BCL2L1-encoded) inhibitors and E7107 remarkably enhances cytotoxicity in cancer cells. These findings inform mechanism-based approaches to the future clinical development of splicing modulators in cancer treatment.

Synaptotagmin 7 in Twist-Related Protein 1-Mediated Epithelial-Mesenchymal Transition of Non-Small Cell Lung Cancer

Background: Twist-related protein 1 (TWIST1) plays an essential role in the carcinogenesis and metastasis of NSCLC. Our aims were to identify a novel molecule at the downstream of TWIST1 that mediates metastasis of NSCLC, and to evaluate its potential as a diagnosis and a prognosis marker. Methods: The functional genes associated with invasion and metastasis at the downstream of TWIST1 were obtained by microarray gene expression analyses in NSCLC cell line. The expression levels of Synaptotagmin 7 (SYT7) in a cohort of patients with NSCLC (n=154) were examined by immunohistochemistry staining, and assessed by Kaplan-Meier survival analysis and Cox regression analysis. The effects of SYT7 on tumorgenesis and metastasis of NSCLC were measured in vitro and in vivo. Findings: We first discovered that SYT7 is significantly altered by TWIST1 expression in microarray gene expression analyses. We further confirmed that SYT7 protein was significantly higher in NSCLC tissues than that in the adjacent normal lung tissues, and higher SYT7 protein expression was associated with poor survival of NSCLC patients. Functional experiments indicated that SYT7 promotes proliferation, invasion and metastasis, and inhibits cell apoptosis of NSCLC cells in vitro and in vivo. We demonstrated that knocking down SYT7 increases expression of E-cadherin and decreases the level of N-cadherin and Vimentin of cultured cells, indicating an involvement of EMT by SYT7. Interpretation: Our data indicate that SYT7 is an important promoter for EMT and tumor progression in NSCLC. Funding: This project was supported by grants from the Major Scientific and Technological Innovation Project of Shandong Province (2018CXGC1212), Science and Technology Foundation of Shandong Province (2014GSF118084, 2016GSF121043), Medical and Health Technology Innovation Plan of Jinan City (201805002) and the National Natural Science Foundation of China (81372333). Declaration of Interest: No potential conflicts of interest were disclosed. Ethical Approval: This study was conducted with the approval of the ethical committees of Qilu Hospital of Shandong University (Jinan, China).

USP17 is required for trafficking and oncogenic signaling of mutant EGFR in NSCLC cells

BackgroundThe deubiquitinase USP17 is overexpressed in NSCLC and has been shown to be required for the growth and motility of EGFR wild-type (WT) NSCLC cells. USP17 is also required for clathrin-mediated endocytosis of EGFR. Here, we examine the impact of USP17 depletion on the growth, as well as EGFR endocytosis and signaling, of EGFR mutant (MT) NSCLC cells. In particular, we examine NSCLC cells harboring an EGFR activating exon 19 deletion (HCC827), or both the L858R activating mutation and the T790M resistance gatekeeper mutation (H1975) which renders them resistant to EGFR tyrosine kinase inhibitors (TKIs).MethodsMTT, trypan blue and clonogenic assays, confocal microscopy, Western blotting and cell cycle analysis were performed.ResultsUSP17 depletion blocks the growth of EGFRMT NSCLC cells carrying either the EGFR exon 19 deletion, or L858R/T790M double mutation. In contrast to EGFRWT cells, USP17 depletion also triggers apoptosis of EGFRMT NSCLC cells. USP17 is required for clathrin-mediated endocytosis in these EGFRMT NSCLC cells, but it is not required for the internalization of the mutated EGFR receptors. Instead, USP17 depletion alters the localization of these receptors within the cell, and although it does not decrease basal EGFR activation, it potently reduces activation of Src, a key kinase in mutant EGFR-dependent tumorigenicity. Finally, we demonstrate that USP17 depletion can trigger apoptosis in EGFRWT NSCLC cells, when combined with the EGFR tyrosine kinase inhibitor (TKI) gefitinib.ConclusionsOur data reveals that USP17 facilitates trafficking and oncogenic signaling of mutant EGFR and indicates targeting USP17 could represent a viable therapeutic strategy in NSCLC tumours carrying either an EGFR activating mutation, or a resistance gatekeeper mutation.

Cryptotanshinone Induces Cell Cycle Arrest and Apoptosis of NSCLC Cells through the PI3K/Akt/GSK-3β Pathway.

Cryptotanshinone (CTT) is a natural product and a quinoid diterpene isolated from the root of the Asian medicinal plant, Salvia miltiorrhizabunge. Notably, CTT has a variety of anti-cancer actions, including the activation of apoptosis, anti-proliferation, and reduction in angiogenesis. We further investigated the anti-cancer effects of CTT using MTS, LDH, and Annexin V assay, DAPI staining, cell cycle arrest, and Western blot analysis in NSCLC cell lines. NSCLC cells treated with CTT reduced cell growth through PI3K/Akt/GSK3β pathway inhibition, G0/G1 cell cycle arrest, and the activation of apoptosis. CTT induced an increase of caspase-3, caspase-9, poly-ADP-ribose polymerase (PARP), and Bax, as well as inhibition of Bcl-2, survivin, and cellular-inhibitor of apoptosis protein 1 and 2 (cIAP-1 and -2). It also induced G0/G1 phase cell cycle arrest by decreasing the expression of the cyclin A, cyclin D, cyclin E, Cdk 2, and Cdk 4. These results highlight anti-proliferation the latent of CTT as natural therapeutic agent for NSCLC. Therefore, we investigated the possibility of CTT as an anti-cancer agent by comparing with GF, which is a representative anti-cancer drug.

Blocking IL-13 receptor α2 using polyethylene glycol functionalized superparamagnetic iron oxide nanocarriers to inhibit proliferation and mediate apoptosis in NSCLC cells

Blocking IL-13 receptor α2 using polyethylene glycol functionalized superparamagnetic iron oxide nanocarriers to inhibit proliferation and mediate apoptosis in NSCLC cells

Suppressed translation as a mechanism of initiation of CASP8 (caspase 8)-dependent apoptosis in autophagy-deficient NSCLC cells under nutrient limitation

ABSTRACTMacroautophagy/autophagy inhibition under stress conditions is often associated with increased cell death. We found that under nutrient limitation, activation of CASP8/caspase-8 was significantly increased in autophagy-deficient lung cancer cells, which precedes mitochondria outer membrane permeabilization (MOMP), CYCS/cytochrome c release, and activation of CASP9/caspase-9, indicating that under such conditions the activation of CASP8 is a primary event in the initiation of apoptosis as well as essential to reduce clonogenic survival of autophagy-deficient cells. Starvation leads to suppression of CFLAR proteosynthesis and accumulation of CASP8 in SQSTM1 puncta. Overexpression of CFLARs reduces CASP8 activation and apoptosis during starvation, while its silencing promotes efficient activation of CASP8 and apoptosis in autophagy-deficient U1810 lung cancer cells even under nutrient-rich conditions. Similar to starvation, inhibition of protein translation leads to efficient activation of CASP8 and cell death in autophagy-deficient lung cancer cells. Thus, here for the first time we report that suppressed translation leads to activation of CASP8-dependent apoptosis in autophagy-deficient NSCLC cells under conditions of nutrient limitation. Our data suggest that targeting translational machinery can be beneficial for elimination of autophagy-deficient cells via the CASP8-dependent apoptotic pathway.

Sphingosine kinase-2 Inhibitor ABC294640 Enhances Doxorubicin-Induced Apoptosis of NSCLC Cells via Altering Survivin Expression.

There is an urgent need to improve efficacy of chemotherapeutics to overcome resistance in cancer treatment. Sphingosine kinase-2 (SphK2) a key regulator of sphingolipid signaling has been rationalized as an important therapeutic target. We evaluated the role of SphK2 in doxorubicin (DOX)-induced apoptosis of NSCLC cells via altering c-FLIPS, MCL-1 and survivin expressions in order to overcome chemoresistance. Proliferation and apoptosis were evaluated by MTT assay and DAPI staining, respectively. Cell population in each phase of cell cycle was determined by flow cytometric assay. Gene and protein expression levels were examined by quantitative RT-PCR and western blot analysis, respectively. Phorbol myristate acetate (PMA), a SphK2 stimulator, decreased cell death induced by IC50 of DOX (1.1 µM) to around 70% (p<0.01). Cell cycle analysis revealed a significant accumulation of the cells in S phase with a marked decrease in sub G1 phase when we incubated the cells with combined treatment of PMA and DOX (p<0.05). Adding ABC294640 (40 µM), a SphK2 inhibitor, significantly abolished PMA effect on cell survival (p<0.01). Survivin expression was significantly diminished by applying ABC294640 either alone or in DOX treated cells followed by increase in cell death (p<0.05), however, there was no significant change in MCL-1 expression by ABC294640 either alone or in DOX treated cells (p=0.16) and (p=0.06), respectively. Identifying cancer patients with high SphK2 expression and then inhibiting of SphK2 activity can be considered as an important strategy to increase the efficacy of DOX in the induction of apoptosis.

Artocarpin, an isoprenyl flavonoid, induces p53-dependent or independent apoptosis via ROS-mediated MAPKs and Akt activation in non-small cell lung cancer cells.

Artocarpin has been shown to exhibit cytotoxic effects on different cancer cells, including non-small cell lung carcinoma (NSCLC, A549). However, the underlying mechanisms remain unclear. Here, we explore both p53-dependent and independent apoptosis pathways in artocarpin-treated NSCLC cells. Our results showed that artocarpin rapidly induced activation of cellular protein kinases including Erk1/2, p38 and AktS473. Inhibition of these protein kinases prevented artocarpin-induced cell death. Moreover, artocarpin-induced phosphorylation of these protein kinases and apoptosis were mediated by induction of reactive oxygen species (ROS), as pretreatment with NAC (a ROS scavenger) and Apocynin (a Nox-2 inhibitor) blocked these events. Similarly, transient transfection of p47Phox or p91Phox siRNA attenuated artocarpin-induced NADPH oxidase activity and cell death. In addition, p53 dependent apoptotic proteins including PUMA, cytochrome c, Apaf-1 and caspase 3 were activated by artocarpin, and these effects can be abolished by antioxidants, MAPK inhibitors (U0126 and SB202190), but not by PI3K inhibitor (LY294002). Furthermore, we found that artocarpin-induced Akt phosphorylation led to increased NF-κB activity, which may act as an upstream regulator in the c-Myc and Noxa pathway. Therefore, we propose that enhancement of both ERK/ p38/ p53-dependent or independent AktS473/NF-κB/c-Myc/Noxa cascade by Nox-derived ROS generation plays an important role in artocarpin-induced apoptosis in NSCLC cells.

Cordycepin induces autophagy-mediated c-FLIPL degradation and leads to apoptosis in human non-small cell lung cancer cells.

Cordycepin, a main active composition extracted from Cordyceps militaris, has been reported to exert anti-tumor activity in a broad spectrum of cancer types. However, the function of cordycepin on human non-small cell lung cancer cells is still obscure. Our present work showed that cordycepin inhibited cell growth by inducing apoptosis and autophagy in human NSCLC cells. Further study revealed that cordycepin triggered extrinsic apoptosis associated with down-regulation of c-FLIPL which suppresses the activity of caspase-8. And ectopic expression of c-FLIPL dramatically prevented cordycepin-caused apoptosis. Meanwhile, cordycepin stimulated autophagy through suppressing mTOR signaling pathway in lung cancer cells. When autophagy was blocked by Atg5 siRNA or PI3K inhibitor LY294002, the levels of apoptosis caused by cordycepin were obviously attenuated. In addition, suppression of autophagy could also elevate the level of c-FLIPL which indicated cordycepin-triggered autophagy promoted the degradation of c-FLIPL. Therefore, we conclude that cordycepin induces apoptosis through autophagy-mediated downregulation of c-FLIPL in human NSCLC cells. Taken together, our findings provide a novel prospect on the anti-tumor property of cordycepin, which may further prompt cordycepin to serve as a promising therapeutic approach in NSCLC treatment.

Abstract C93: RYBP predicts survival of patients with non-small cell lung cancer and sensitizes chemotherapy

Abstract Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers and associates with a poor prognosis. Despite several targeted therapies have been developed with promising results, the therapeutic options for NSCLC are limited and the 5-year survival rate remains poor (∼15%). Therefore, there is an urgent need for a better understanding of its pathogenesis and exploring novel therapeutic targets. Ring1 and YY1 binding protein (RYBP) is a member of polycomb group (PcG) proteins that typically act as transcriptional repressors via epigenetic modification of chromatin and participate in the establishment and maintenance of cell fates. Recent studies have shown that RYBP also possesses PcG-independent functions that promote apoptosis and cell cycle arrest in cancer cells. Our previous study has shown that RYBP stabilizes p53 through inhibiting MDM2 activity. Recent study indicates that RYBP is downregulated in human cancers, including NSCLC, but the underlying mechanisms are largely unknown. The present study was designed to demonstrate the molecular role of RYBP in NSCLC development and progression, chemotherapy, and patient survival. We systemically investigated the expression of RYBP in human NSCLC tissues and matched non-cancerous samples and evaluated the associations between the RYBP expression in NSCLCs and patient survial. We also generated a replication-deficient recombinant adenovirus driving the expression of RYBP (Adv-RYBP) and carried out in vitro and in vivo studies to explore the molecular basis for the tumor suppressing role of RYBP in NSCLC. We first demonstrated that the RYBP mRNA and protein expressions levels were significantly down-regulated in NSCLC tissues compared with matched noncancerous lung tissues. The low expression of RYBP was significantly associated with the poor prognosis in NSCLC patients. We then identified that enforced RYBP expression decreased cell viability, inhibited colony formation and induced apoptosis in NSCLC cells, while RYBP knockdown led to the opposite effects. RYBP affected the expression of several apoptosis-related proteins; and promoting apoptosis was one of the main mechanisms of RYBP-mediated cell growth inhibition in NSCLC. Moreover, AdRYBP led to a decreased NSCLC tumor xenograft growth. Additionally, clinically used chemotherapeutic agents induced the expression of RYBP, and RYBP sensitized NSCLC cells to chemotherapy in vitro and in vivo. In conclusion, our results reveal that RYBP is a potential biomarker for the diagnosis and prognosis of NSCLC and that reactivating RYBP in cancer cells may provide an effective and safe therapeutic approach to NSCLC therapy. (Supported by NIH/NCI grants R01 CA186662). Citation Format: wei wang, Sukesh Voruganti, Jiang-Jiang Qin, Biyun Qian, Ruiwen Zhang. RYBP predicts survival of patients with non-small cell lung cancer and sensitizes chemotherapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C93.

USP22 promotes NSCLC tumorigenesis via MDMX up-regulation and subsequent p53 inhibition.

Increasing evidence suggests that ubiquitin-specific protease 22 (USP22) has great clinicopathologic significance in oncology. In this study, we investigated the role of USP22 in human NSCLC tumorigenesis along with the underlying mechanisms of action. First, we determined the expression of USP22 in human NSCLC, as well as normal tissues and cell lines. We then studied the effects of USP22 silencing by shRNA on NSCLC cell growth in vitro and tumorigenesis in vivo, along with the effect on the p53 pathway. We found that USP22 is overexpressed in human NSCLC tissues and cell lines. USP22 silencing by shRNA inhibits proliferation, induces apoptosis and arrests cells at the G0/G1 phases in NSCLC cells and curbs human NSCLC tumor growth in a mouse xenograft model. Additionally, USP22 silencing downregulates MDMX protein expression and activates the p53 pathway. Our co-immunoprecipitation analysis shows that USP22 interacts with MDMX in NSCLC cells. Furthermore, MDMX silencing leads to growth arrest and apoptosis in NSCLC cells, and over-expression of MDMX reverses the USP22 silencing-induced effects. Taken together, our results suggest that USP22 promotes NSCLC tumorigenesis in vitro and in vivo through MDMX upregulation and subsequent p53 inhibition. USP22 may represent a novel target for NSCLC treatment.

BRMS1 regulates apoptosis in non-small cell lung cancer cells.

Breast cancer metastasis suppressor 1 (BRMS1) was originally identified as a metastasis suppressor gene in human breast cancer. Previous studies have reported that loss of BRMS1 expression correlates with tumor progression, and poor prognosis in NSCLC. However, the role of BRMS1 in NSCLC is not fully understood. In this study, we found that expression of BRMS1 in A549 cells did not affect cell growth under normal culture conditions but sensitized cells to apoptosis induced by serum deprivation. Consistently, knockdown of endogenous BRMS1 expression in H1299 cells suppressed cell apoptosis. We identified that BRMS1 regulate apoptosis in NSCLC cells by modulating Stat3 activation. Taken together, our results show that BRMS1 sensitizes NSCLC cells to apoptosis through Stat3 signaling pathway, suggesting a potential role of BRMS1 in regulating NSCLC apoptosis and metastasis.

Parthenolide induces apoptosis via TNFRSF10B and PMAIP1 pathways in human lung cancer cells

BackgroundParthenolide (PTL) is a sesquiterpene lactone which can induce apoptosis in cancer cells and eradicate cancer stem cells such as leukemia stem cells, prostate tumor-initiating cells and so on. However, the mechanism remains largely unclear.MethodsLung cancer cells were treated with parthenolide and the cell lysates were prepared to detect the given proteins by Western Blot analysis, and the cell survival was assayed by SRB and MTT assay. Cell cycle was evaluated by DNA flow cytometry analysis. TNFRSF10B, PMAIP1, ATF4 and DDIT3 genes were knocked down by siRNA technique. Apoptosis was evaluated by using Annexin V-FITC/PI staining and flow cytometry analysis.ResultsParthenolide (PTL) induces apoptosis and cell cycle arrest in human lung cancer cells. Moreover, PTL treatment in NSCLC cells increases expression of TNFRSF10B/DR5 and PMAIP1/NOXA. Silencing of TNFRSF10B or PMAIP1 or overexpression of CFLAR /c-FLIP (long form) could protect cells from PTL-induced apoptosis. Furthermore, PTL could increase the levels of endoplasmic reticulum stress hallmarks such as ERN1, HSPA5, p-EIF2A, ATF4 and DDIT3. Knockdown of ATF4 and DDIT3 abrogated PTL-induced apoptosis, which suggested that PTL induced apoptosis in NSCLC cells through activation of endoplasmic reticulum stress pathway. More importantly, we found that ATF4, DDIT3, TNFRSF10B and PMAIP1 were up-regulated more intensively, while CFLAR and MCL1 were down-regulated more dramatically by PTL in A549/shCDH1 cells than that in control cells, suggesting that PTL preferred to kill cancer stem cell-like cells by activating more intensive ER stress response in cancer stem cell-like cells.ConclusionWe showed that parthenolide not only triggered extrinsic apoptosis by up-regulating TNFRSF10B and down-regulating CFLAR, but also induced intrinsic apoptosis through increasing the expression of PMAIP1 and decreasing the level of MCL1 in NSCLC cells. In addition, parthenolide triggered stronger ER stress response in cancer stem cell-like cells which leads to its preference in apoptotic induction. In summary, PTL induces apoptosis in NSCLC cells by activating endoplasmic reticulum stress response.

Capilliposide Isolated from Lysimachia capillipes Hemsl. Induces ROS Generation, Cell Cycle Arrest, and Apoptosis in Human Nonsmall Cell Lung Cancer Cell Lines

Several data has reported that capilliposide, extracted from a traditional Chinese medicine, Lysimachia capillipes Hemsl. (LC) could exhibit inhibitory effect on cell proliferation in various cancers. The current study investigated the antitumor efficacy of Capilliposide and elucidated its potential molecular mechanism involved in vivo and vitro. Our results indicated that LC capilliposide inhibited proliferation of lung cancer cells in a dose-dependent manner. LC capilliposide induced cell cycle arrest at the S stage and enhanced apoptosis in NSCLC cells. Treatment with LC capilliposide increased the intracellular level of ROS, which activated the mitochondrial apoptotic pathway. Blockage of ROS by NAC highly reversed the effect of LC capilliposide on apoptosis. Xenograft tumor growth was significantly lower in the LC-treated group compared with the untreated control group (P < 0.05). The results also show that LC treatment does not produce any overt signs of acute toxicity in vivo. These findings demonstrate that LC capilliposide could exert an anti-tumor effect on NSCLC through mitochondrial-mediated apoptotic pathway and the activation of ROS is involved.

Prognostic and therapeutic relevance of FLIP and procaspase-8 overexpression in non-small cell lung cancer

Non-small cell lung carcinoma remains by far the leading cause of cancer-related deaths worldwide. Overexpression of FLIP, which blocks the extrinsic apoptotic pathway by inhibiting caspase-8 activation, has been identified in various cancers. We investigated FLIP and procaspase-8 expression in NSCLC and the effect of HDAC inhibitors on FLIP expression, activation of caspase-8 and drug resistance in NSCLC and normal lung cell line models. Immunohistochemical analysis of cytoplasmic and nuclear FLIP and procaspase-8 protein expression was carried out using a novel digital pathology approach. Both FLIP and procaspase-8 were found to be significantly overexpressed in tumours, and importantly, high cytoplasmic expression of FLIP significantly correlated with shorter overall survival. Treatment with HDAC inhibitors targeting HDAC1-3 downregulated FLIP expression predominantly via post-transcriptional mechanisms, and this resulted in death receptor- and caspase-8-dependent apoptosis in NSCLC cells, but not normal lung cells. In addition, HDAC inhibitors synergized with TRAIL and cisplatin in NSCLC cells in a FLIP- and caspase-8-dependent manner. Thus, FLIP and procaspase-8 are overexpressed in NSCLC, and high cytoplasmic FLIP expression is indicative of poor prognosis. Targeting high FLIP expression using HDAC1–3 selective inhibitors such as entinostat to exploit high procaspase-8 expression in NSCLC has promising therapeutic potential, particularly when used in combination with TRAIL receptor-targeted agents.

Plumbagin induces apoptotic and autophagic cell death through inhibition of the PI3K/Akt/mTOR pathway in human non-small cell lung cancer cells

Plumbagin (PLB) has shown anti-cancer activity but the mechanism is unclear. This study has found that PLB has a potent pro-apoptotic and pro-autophagic effect on A549 and H23 cells. PLB arrests cells in G2/M phase, and increases the intracellular level of reactive oxygen species in both cell lines. PLB dose-dependently induces autophagy through inhibition of PI3K/Akt/mTOR pathway as indicated by reduced phosphorylation of Akt and mTOR. Inhibition or induction of autophagy enhances PLB-induced apoptosis. There is crosstalk between PLB-induced apoptosis and autophagy. These findings indicate that PLB initiates both apoptosis and autophagy in NSCLC cells through coordinated pathways.