Retracted: Arsenic Trioxide Inhibits the Metastasis of Small Cell Lung Cancer by Blocking Calcineurin-Nuclear Factor of Activated T Cells (NFAT) Signaling.

This publication has been retracted by the Editor due to the identification of non-original figure images and manuscript content that raise concerns regarding the credibility and originality of the study. Reference: Jin-Cheng Zheng, Ke-Jie Chang, Yu-Xiang Jin, Xue-Wei Zhao, Bing Li, Meng-Hang Yang. Arsenic Trioxide Inhibits the Metastasis of Small Cell Lung Cancer by Blocking Calcineurin-Nuclear Factor of Activated T Cells (NFAT) Signaling. Med Sci Monit 2019; 25:2228-2237. DOI: 10.12659/MSM.913091.

Clinicopathologic Features and Survival Outcomes of Primary Lung Mucinous Adenocarcinoma Based on Different Radiologic Subtypes.

BACKGROUND: Primary lung mucinous adenocarcinomas (LMAs) could be subclassified as the pure-solid, part-solid, and pneumonic types according to the findings of high-resolution computed tomography. This study aimed to expound on the clinicopathologic, radiologic, and prognostic characteristics of LMAs based on radiologic classification within a large set of patients. METHODS: From November 2009 to December 2016, this study enrolled 294 resected LMAs, which were divided into the pure-solid (n = 169), part-solid (n = 87), and pneumonic (n = 38) types. The clinicopathologic and radiologic characteristics of the tumors were evaluated, and patient prognosis was determined through follow-up evaluation. Survival outcomes were calculated by Kaplan-Meier curves and compared using log-rank tests. The prognostic impact of clinicopathologic variables, including radiologic presentations, were evaluated by establishing a Cox proportional hazards model. RESULTS: The LMAs were infrequently associated with lymph node metastasis (5.4 %), lymphatic/vascular invasion (4.4 %), or visceral pleural invasion (5.1 %). During the median 71-month follow-up period, recurrence was observed in 62 patients and death in 44 patients. The patients with pneumonic-type LMAs had a poorer prognosis (5-year recurrence-free survival [RFS], 23.7 %; 5-year overall survival [OS], 44.7 %) than those with the pure-solid type (RFS, 83.2 %; OS, 100 %) or part-solid type (RFS, 93.7 %; OS, 100 %). Besides, lymph node metastasis, emphysema, and clinical T stage were independent predictors of RFS and OS. CONCLUSION: Solitary-type LMA patients had excellent prognoses, whereas the survival outcomes for pneumonic-type LMA patients were dismal. Furthermore, pneumonic-type LMA patients were prone to intrapulmonary metastasis by means of aerogenous dissemination rather than distant metastasis.

Air bronchogram on chest CT in radiological pure-solid appearance lung cancer: Correlation analysis with genetic pathological features and survival outcomes.

PURPOSE: To investigate the correlation of air bronchogram sign with clinicopathological characteristics and prognosis in patients with clinical stage (c-stage) I non-small cell lung cancer (NSCLC) with radiological pure-solid appearance. METHOD: We retrospectively evaluated 276 patients with pure-solid c-stage I NSCLC and assessed the correlation between the air bronchogram and clinicopathological characteristics. A Cox proportional hazards model was performed to identify the effect of air bronchogram and clinicopathological variables on oncological outcomes. Recurrence-free survival (RFS) and overall survival (OS) were calculated by Kaplan-Meier curves and were compared using log-rank tests. RESULTS: Presence of air bronchogram was associated with a well differentiated degree (P =.026), higher incidence of EGFR mutation (P <.001) and lower recurrence(P =.021). Kaplan-Meier survival curves showed that air bronchogram group was associated with favorable RFS(67.0% vs. 50.2%; P =.015). A multivariable analysis revealed that air bronchogram and EGFR mutation were independent significant prognostic factors associated with RFS (hazard ratio [HR] = 0.495, 95% confidence interval [CI]: 0.322-0.761, P =.001; HR = 1.625, 95% CI: 1.074-2.457, P =.021; respectively), but not with OS. Additionally, we found that pathological lymph node metastasis was identified as an independent prognostic factor associated with poor RFS and OS(HR = 2.808, 95% CI: 1.913-4.123, P <.001 for RFS; HR = 1.983, 95% CI: 1.185-3.318, P =.009 for OS). CONCLUSIONS: Presence of air bronchogram was associated with well differentiated degree, higher incidence of EGFR mutation and had additional positive prognostic value for RFS in c-stage I NSCLC with a radiological pure-solid appearance.

MDM2-mediated Inhibitory Effect of Arsenic Trioxide on Small Cell Lung Cancer Cell Line by Degrading Mutant p53.

INTRODUCTION: Small cell lung cancer (SCLC) is featured by a high TP53 mutant rate. Our previous research found that arsenic trioxide (As2O3) could significantly inhibit the growth and metastasis of SCLC. Studies have shown that the degradation of mutant p53 mediated by murine double minute 2 (MDM2) can be induced by As2O3, which probably contributes to the inhibition of SCLC, but the detailed mechanism is still unclear. We aimed to testify that As2O3 can inhibit the growth of SCLC cells by degrading mutant p53 protein via binding to MDM2. METHODS: CCK-8 assay, cell cycle analysis, and western blot of apoptosis markers were used to evaluate the inhibitory effect of As2O3 on NCI-H446 cells (containing mutant p53) and NCI-H1299 cells (p53 null). The effects of As2O3 on p53 and its downstream proteins were identified by western blot using mut-p53-knockdown and overexpressed cell models. MDM2-knockdown cell models were constructed, and western blot, co-IP of mut-p53, and ubiquitin were carried out to explore the mediating effect of MDM2 in As2O3 induced mut-p53 degradation. RESULTS: As2O3 inhibited proliferation and induced cell cycle arrest and apoptosis of SCLC cells in a dose- and timedependent manner. After mut-p53 knockdown or overexpressed, the inhibitory effect of As2O3 was dampened or enhanced. Additionally, As2O3-induced mut-p53 ubiquitination was significantly weakened after MDM2 knockdown. CONCLUSION: As2O3 could inhibit SCLC cells by inhibiting proliferation and inducing cell cycle arrest and apoptosis. These inhibitory effects were achieved at least in part by upregulating MDM2, which, in turn, promotes ubiquitination and degradation of mut-p53.

Arsenic Inhibits Proliferation and Induces Autophagy of Tumor Cells in Pleural Effusion of Patients with Non-Small Cell Lung Cancer Expressing EGFR with or without Mutations via PI3K/AKT/mTOR Pathway.

To clarify whether arsenic could exert inhibitory effects on tumor cells in pleural effusions of patients with non-small cell lung cancer (NSCLC), 36 NSCLC pleural effusion samples were collected from Changzheng Hospital and Ruijin Hospital, from 2019 to 2022. The genotype of epidermal growth factor receptor (EGFR) was identified. Tumor cells were isolated and treated with arsenic trioxide (ATO) or/and gefitinib. Additionally, six patients were intrapleurally administrated with ATO. Results showed that 25 samples bore EGFR wild type (WT) and 11 harbored EGFR mutations, including 6 with L858R, 3 with ΔE746-A750, and 2 with T790M. ATO diminished the number of tumor cells from patients with WT and mutant EGFR, down-regulated the expression or phosphorylation of EGFR, pmTOR, PI3K, PTEN, and p4E-BP1, and up-regulated the expression of LC3. Immunofluorescent experiments showed that ATO enhanced LC3 and P62. By contrast, gefitinib was only effective in those harboring EGFR sensitizing mutations. Notably, in patients with intrapleural ATO injection, the pleural effusion underwent a bloody to pale yellow color change, the volume of the pleural effusion was reduced, and the number of the tumor cells was significantly reduced. In conclusion, arsenic is effective against NSCLC with various EGFR genotypes in vitro and in vivo, and potentially circumvents gefitinib resistance.

Programmable DNA Circuit-Facilitated Determination of Circulating Extracellular Vesicle PD-L1 for Lung Cancer Diagnosis and Immunotherapy Response Prediction.

Circulating extracellular vesicle (EV) PD-L1 is correlated with the occurrence and progression of lung cancer and has great potential as a valuable diagnostic and immunotherapy predictive biomarker. In this work, we propose a fluorescent biosensing method for the sensitive and accurate determination of circulating EV PD-L1. Specifically, after the phosphatidylserine-targeting peptide-assisted magnetic enrichment, a programmable DNA circuit is designed to translate the presence of PD-L1 to the appearance of numerous duplex DNA probes on the circulating EV surface. Upon fructose treatment, these newly formed duplex DNA probes are released from the EV surface to activate the trans-cleavage activity of CRISPR/Cas12a system, which finally produces a significant fluorescence signal. Experimental results reveal that the method not only enables sensitive determination of EV PD-L1 with a detection limit of 67 particles/mL but also demonstrates the potential use in the diagnosis and immunotherapy response prediction of lung cancer in a principle-of-proof study. Therefore, the method may provide a useful tool for EV PD-L1 determination, which may provide valuable information for the precise diagnosis and personalized treatment of lung cancer patients.

Arsenic trioxide elicits anti-tumor activity by inhibiting polarization of M2-like tumor-associated macrophages via Notch signaling pathway in lung adenocarcinoma.

Drug-resistant advanced lung adenocarcinoma (LUAD) is an aggressive malignancy with limited treatment options. A therapeutic strategy for drug-resistant LUAD is to target the tumor associated macrophages (TAMs), because they play an important role in tumor immune escape, progression and metastasis. In this study, we conducted in vivo and in vitro investigation of the inhibitory effect of arsenic trioxide (ATO) on polarization of TAMs educated by LUAD. We found that ATO at a concentration of 4 µM disrupted the Notch-dependent positive feedback loop between LUAD and TAMs. In this loop, ATO inhibited the expression of Jagged1 and Notch1 in LUAD and suppressed M2 polarization via down-regulating Notch-dependent paracrine of CCL2 and IL1ß. As a result, the secretion of M2-derived TGF-ß1 decreased, thus inducing inhibitions of LUAD proliferation, migration, invasion, colony formation and epithelial-mesenchymal transition. In xenograft mouse models, ATO significantly inhibited tumor growth and down-regulated infiltration of M2-like TAMs in tumor tissues. In clinical LUAD biopsy samples, high Jagged1/Notch1 expression positively correlated with tumor-infiltrated M2-like TAMs, leading to poor prognosis. In conclusion, our results identified a novel tumor immunomodulating function for ATO, which can inhibit the polarization of M2-type TAMs to exert anti-tumor effects in the tumor microenvironment. Our results demonstrated the translational potential of repurposing ATO to target TAMs for lung adenocarcinoma treatment.

Small cell lung cancer transformation and tumor heterogeneity after sequential targeted therapy and immunotherapy in EGFR-mutant non-small cell lung cancer: A case report.

Background: Histological transformation from non-small cell lung cancer (NSCLC) to small cell lung cancer (SCLC) is one of mechanisms of the acquired resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI). However, SCLC transformation and tumor heterogeneity have never been reported in sequential targeted therapy and immunotherapy. Case presentation: Here, we described a patient with advanced EGFR-mutant NSCLC, who received erlotinib and underwent the resistance with EGFR T790M (-). The patient then received chemotherapy plus immunotherapy of programmed cell death 1 (PD-1) inhibitor, encountered progression with pathological transformation from NSCLC to SCLC that was overcome by chemotherapy of etoposide plus carboplatin (EC) with the main lesion significantly shrinking while metastatic nodules increasing. The pathology of the metastatic nodule showed NSCLC with EGFR T790M (+). Based on the tumor heterogeneity, EC chemotherapy combined with osimertinib was used, and patients responded well. The patient experienced four lung biopsies in all, which helped to provide the patient with precise treatment. Conclusions: This case suggested that SCLC transformation and tumor heterogeneity should be paid attention to when disease progression occurred in advanced NSCLC whether receiving targeted therapy or immunotherapy.

Arsenic Trioxide Restrains Lung Cancer Growth and Metastasis by Blocking the Calcineurin-NFAT Pathway by Upregulating DSCR1.

BACKGROUND: Anti-angiogenesis therapy mostly aimed at targeting vascular endothelial growth factor (VEGF) and its receptors have been widely applied to lung cancer. However, the improvement in the patient's overall survival remains dissatisfying. Previously, we demonstrated that arsenic trioxide (As2O3) exerts an anti-lung cancer effect through anti-angiogenesis, but the details of the mechanism in play remain unclear. Herein, we focused on the calcineurin-NFAT pathway, downstream of VEGF, and its endogenous inhibitor DSCR1. OBJECTIVE: To demonstrate the mechanism of As2O3 restraining lung cancer growth and metastasis by blocking the calcineurin-NFAT pathway by upregulating DSCR1. METHODS: We constructed xenografts and metastasis models based on wild-type (WT) and DSCR1 knockout (DSCR1-/-) mice, and carried out qPCR, Western blot, immunohistochemistry, in vivo imaging and calculated microvessel density to evaluate the effects of As2O3 on angiogenesis, tumor growth, metastasis, and the protein expression levels of DSCR1 and calcineurin-NFAT pathway-related molecules. RESULTS: As2O3 inhibited tumor growth and metastasis, reduced microvessel formation, and induced vascular lumen malformation in WT mice. At the protein level, As2O3 upregulated DSCR1, downregulated NFAT2 and its downstream molecules, but had no effect on calcineurin A. However, in DSCR1-/- mice, the above-mentioned effects of As2O3 were abolished. CONCLUSION: As2O3 can suppress lung cancer growth and metastasis through anti-angiogenesis effects by blocking the calcineurin-NFAT pathway by upregulating DSCR1. The results shed light on the antitumor mechanism of As2O3 and are a step forward in the identification of As2O3 as a new drug in the treatment of lung cancer.

Efficacy of ICIs on patients with oncogene-driven non-small cell lung cancer: a retrospective study.

Aim: The objective of our study was to assess the efficacy of immune checkpoint inhibitors (ICIs) on patients with non-small-cell lung cancer (NSCLC) harboring oncogenic alterations. Methods: We retrospectively enrolled patients with advanced non-squamous NSCLC who were treated with anti-PD-1-based monotherapy or combined immunotherapy. Major characteristics including PD-L1 expression, treatment, and survival were analyzed. Results: In total, 309 non-squamous NSCLC patients with a median age of 61 years (range 20-88 years) including 70.9% male were retrospectively enrolled. The molecular alterations involved epidermal growth factor receptor (EGFR) (n = 81), V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) (n = 31), anaplastic lymphoma kinase (ALK) (n = 1), human epidermal growth factor receptor 2 (HER2) (n = 12), V-raf murine sarcoma viral oncogene homolog (BRAF) (n = 2), rearranged during transfection (n = 4), and c-ros oncogene 1 (ROS1) (n = 3). In the EGFR subset, the ORR was 30.9% (n = 81) and PFS was significantly shorter than WT group (median PFS: 5.7 months vs. 7.1 months; P = 0.0061). In subgroup analyses, ICI combined therapy was significantly correlated with a longer PFS compared with ICI monotherapy (median PFS: 7.7 months vs. 4.7 months; P = 0.0112). In KRAS patients, ORR was 51.6% (n = 31). No significant difference was found in subgroup analyses. The ORR and PFS were 16.7% (n = 12) and 28.6% (n = 7), 7.8 months and 9.0 months for HER2 and EGFR Exon20 insertion patients, respectively. Three ROS1 patients were enrolled with a PFS of 16.0, 34.2, and 45.0 months individually, and one ALK patient with PFS of 4.4 months was identified. No response was found in two BRAF patients. Conclusion: ICI-based combination therapy can bring benefit to patients with EGFR-mutant NSCLC. ICI-based combination therapy could be considered for patients with ROS1 rearrangement, HER2 mutation and EGFR Exon20 insertion NSCLC.

Notch pathway inhibition mediated by arsenic trioxide depletes tumor initiating cells in small cell lung cancer.

BACKGROUND: Small cell lung cancer (SCLC) is the most malignant type of lung cancer. We previously reported that arsenic trioxide (As2O3) inhibited tumor initiating cells (TICs) of SCLC in vitro. In the present study, we aimed to identify the above effect in vivo and shed light on its underlying mechanism. METHODS AND RESULTS: TICs were enriched by culturing human SCLC cell line as sphere cells in specified serum-free medium. The expression of stem cell markers, CD133 and CD44, and the in vivo tumorigenicity of both TICs and their parental cells were examined. To demonstrate the inhibitory effect of As2O3 on TICs, cell proliferation, clone formation and sphere formation assays were performed. CD133 and Notch pathway-related factors were also measured after As2O3 treatment. Xenograft models were established by injecting TICs into nude mice. Mice were treated with As2O3 for 14 days. Afterwards, the tumor volume and the expression of CD133 and Notch1 were evaluated. TICs obtained by the above-mentioned method showed elevated levels of stem cell markers and increased tumorigenicity compared with their parental cells. As2O3 treatment largely inhibited TICs proliferation, sphere formation and clonogenic capacity. As2O3 also reduced the expression of CD133 and down-regulated Notch pathway in TICs. Furthermore, As2O3 potently inhibited tumor growth, decreased the expression of CD133 and down-regulated Notch1 in tumors originating from TICs. CONCLUSIONS: Our data demonstrate that As2O3 has a remarkable inhibitory effect on TICs of SCLC both in vitro and in vivo, and the mechanism might involve the down-regulation of Notch pathway.

Microbes in lung cancer initiation, treatment, and outcome: Boon or bane?

Lung cancer is the top reason for cancer-related deaths worldwide. The 5-year overall survival rate of lung cancer is approximately 20 % due to the delayed diagnosis and low response rate to regular treatments. Microbiota, both host-microbiota and alien pathogenic microbiota, have been investigated to be involved in a complicated and contradictory relationship with lung cancer initiation, treatments, and prognosis. Disorders of certain host-microbiota and pathogen infection are associated with the risk of lung cancers based on epidemiological evidence, and antibiotics (ATBs) could dramatically impair anti-cancer treatment efficacy, including chemotherapy and immunotherapy. Moreover, probiotics and microbe-mediated drugs are potential approaches to enhance regular anti-tumor treatments. Therefore, the knowledge of the complex dual effect of microbes on lung cancer is beneficial to take their essence and remove their dross. This review offers insight into the current trends and advancements in microbiota or microbial components related to lung cancer.

Case Report: Abscopal Effect of Microwave Ablation in a Patient With Advanced Squamous NSCLC and Resistance to Immunotherapy.

Currently, immunotherapy has been a backbone in the treatment of advanced non-small cell lung cancer (NSCLC) without driver gene mutations. However, only a small proportion of NSCLC patients respond to immune checkpoint inhibitors, and majority of patients with initial response will develop acquired resistance at 5 years, which usually manifests as oligo-progression or oligo-metastases. Evidence from multiple clinical trials indicates that local consolidative therapies could improve the prognosis of oligometastatic NSCLC patients. Herein, we reported a case of advanced squamous lung cancer which showed a durable abscopal effect from microwave ablation after acquired resistance of immunotherapy.

Arsenic trioxide inhibits the growth of cancer stem cells derived from small cell lung cancer by downregulating stem cell-maintenance factors and inducing apoptosis via the Hedgehog signaling blockade.

BACKGROUND: Small cell lung cancer (SCLC) is the most deadly and aggressive type of primary lung cancer, with the 5-year survival rate lower than 5%. The FDA has approved arsenic trioxide (As2O3) for acute promyelocytic leukemia (APL) treatment. However, its role in SCLC-derived cancer stem cells (CSCs) remains largely unknown. METHODS: CSCs were enriched from SCLC cell lines by culturing them as spheres in conditioned serum-free medium. Then, qPCR, western blot, serial passage, limiting dilution, Transwell, and tumorigenesis assay were performed to verify the cells' stem phenotypic characteristics. Anticancer efficiency of As2O3 was assessed in these cells using CCK8, colony formation, sphere formation, flow cytometry, qPCR, western blot analysis in vitro, and tumor growth curve, immunofluorescence, and TUNEL staining analyses in vivo. RESULTS: The fifth-passage SCLC spheres showed a potent self-renewal capacity, higher clonal formation efficiency (CFE), SOX2, c-Myc, NANOG, and OCT4 levels, and invasion ability, and stronger tumorigenesis capacity than the parental SCLC cells, indicating that the SCLC sphere cells displayed CSC features. As2O3 inhibited the proliferation, clonality and sphere forming ability of SCLC-derived CSCs and suppressed the tumor growth of CSCs-derived xenograft tumors. As2O3 induced apoptosis and downregulation of SOX2 and c-Myc in vitro and in xenografts. Besides, SOX2 knockdown suppressed SCLC-derived CSCs to self-renew and induced apoptosis. Mechanistically, expression of GLI1 (a key transcription factor of Hedgehog pathway) and its downstream genes increased in SCLC-derived CSCs, compared to the parental cells. As2O3 dramatically downregulated GLI1 and its downstream genes in vitro and in vivo. The GLI inhibitor (GANT-61) recapitulated and enhanced the effects of As2O3 on SCLC-derived CSCs, including growth suppression, apoptosis induction, and GLI1, SOX2 and c-Myc downregulation. CONCLUSIONS: Altogether, As2O3 effectively suppressed SCLC-derived CSCs growth by downregulating stem cell-maintenance factors and inducing apoptosis. These effects are mediated at least partly via the Hedgehog signaling blockade.

Surgical management of Gorham-Stout syndrome involving the cervical spine with bilateral pleural effusion: A case report and literature review.

Gorham-Stout syndrome (GSS) is a rare disease characterized by spontaneous and progressive osteolysis caused by benign proliferation of lymphatic vessels or capillaries. It most commonly occurs in children or young individuals without any inherited predisposition. GSS most commonly affects the shoulder girdle, pelvis, ribs and skull. Its diagnosis is mainly based on radiological and pathological findings. The present study reports on the case of a 22-year-old male patient diagnosed with GSS involving the C1-T1 vertebrae accompanied by bilateral pleural effusion. Resection of the occipital and cervical vertebral lesions and spinal reconstruction using an internal fixator were successfully performed via the posterior approach. After the surgery, the patient received bisphosphonate treatment and vitamin D supplementation. The pleural effusion gradually decreased. At the 18-month follow-up visit, no evidence of new bone obstruction was present and the patient had no neurological sequelae.

Arsenic Trioxide Suppresses Tumor Growth through Antiangiogenesis via Notch Signaling Blockade in Small-Cell Lung Cancer.

Small-cell lung cancer (SCLC) is a highly malignant type of lung cancer with no effective second-line chemotherapy drugs. Arsenic trioxide (As2O3) was reported to exert antiangiogenesis activities against lung cancer and induce poor development of vessel structures, similar to the effect observed following the blockade of Notch signaling. However, there are no direct evidences on the inhibitory effects of As2O3 on tumor growth and angiogenesis via blockade of Notch signaling in SCLC. Here, we found that As2O3 significantly inhibited the tumor growth and angiogenesis in SCLC and reduced the microvessel density. As2O3 disturbed the morphological development of tumor vessels and downregulated the protein levels of delta-like canonical Notch ligand 4 (Dll4), Notch1, and Hes1 in vivo. DAPT, a Notch signaling inhibitor, exerted similar effects in SCLC. We found that both As2O3 treatment and Notch1 expression knockdown resulted in the interruption of tube formation by human umbilical vein endothelial cells (HUVECs) on Matrigel. As2O3 had no effects on Dll4 level in HUVECs but significantly inhibited the expression of Notch1 and its downstream gene Hes1 regardless of Dll4 overexpression or Notch1 knockdown. These findings suggest that the antitumor activity of As2O3 in SCLC was mediated via its antiangiogenic effect through the blockade of Notch signaling, probably owing to Notch1 targeting.

Arsenic Trioxide Inhibits the Metastasis of Small Cell Lung Cancer by Blocking Calcineurin-Nuclear Factor of Activated T Cells (NFAT) Signaling.

BACKGROUND The inhibitory effect of arsenic trioxide (As2O3) on lung cancer has been reported in some preclinical studies. However, its effect on small cell lung cancer (SCLC) has been poorly explored. Calcineurin and its substrate, nuclear factor of activated T cells (NFAT), mediate the downstream signaling of VEGF, and is critical in the process endothelium activation and tumor metastasis. In this study, we aimed to evaluate whether As2O3 had inhibitory effects on endothelial cells activation and the metastasis of SCLC, and to explore the possible mechanisms. MATERIAL AND METHODS In vitro, human umbilical vein endothelial cells (HUVECs) were used. Cell Counting Kit-8 assay and cell migration assay were performed to determine the effect of As2O3 on HUVECs proliferation and migration. The level of calcineurin, NFAT, downstream factors for Down syndrome candidate region 1 (DSCR1), and the endogenous inhibitor of calcineurin, were evaluated by quantitative PCR and western blotting. In vivo, SCLC metastasis models were established by injecting NCI-H446 cells into tail veins of nude mice. Tumor-bearing mice were treated with As2O3 or calcineurin inhibitor for 10 days, after which tumor metastasis in target organs was evaluated. RESULTS As2O3 significantly inhibited the proliferation and migration of endothelial cells. Also, As2O3 inhibited the expression levels of calcineurin, NFAT, and the downstream target genes CXCR7 and RND1, while it upregulated the level of DSCR1. Both As2O3 and calcineurin inhibitor exhibited notable inhibitory effect on the metastasis of SCLC, without obvious side effects. CONCLUSIONS These findings suggested that As2O3 had remarkable inhibitory effects on the endothelial cell activation and SCLC metastasis, and the mechanism might be related to the blocking of calcineurin-NFAT signaling by upregulating DSCR1.

Anti-angiogenic effect of arsenic trioxide in lung cancer via inhibition of endothelial cell migration, proliferation and tube formation.

Arsenic trioxide (As2O3) exhibits a remarkable effect on leukemia treatment; however, its effect on solid tumors remains poorly explored. The present study demonstrated the inhibitory effect of As2O3 on lung cancer and explored its possible mechanism. It was observed that As2O3 significantly inhibited the growth of lung cancer xenografts and tumor angiogenesis in vivo. The inhibitory effect of As2O3 on cell proliferation in vitro was more remarkable in vascular endothelial cells than in lung cancer cells. It was also observed that As2O3 inhibited the migration of vascular endothelial cells and disrupted vascular tube formation on Matrigel assays. In addition, a series of key signaling factors involved in multiple stages of angiogenesis, including matrix metalloproteinase (MMP)-2, MMP-9, platelet-derived growth factor (PDGF)-BB/PDGF receptor-ß, vascular endothelial growth factor (VEGF)-A/VEGF receptor-2, basic fibroblast growth factor (FGF)/FGF receptor-1 and delta like canonical Notch ligand 4/Notch-1, were regulated by As2O3. These findings suggested that anti-angiogenesis may be an underlying mechanism of As2O3 anticancer activity in lung cancer.

Arsenic trioxide inhibits cancer stem-like cells via down-regulation of Gli1 in lung cancer.

Cancer stem cells (CSCs) are responsible for the tumorigenesis and recurrence, so targeting CSCs is a potential effective method to cure cancers. Activated Hedgehog signaling pathway has been proved to be implicated in the maintenance of self-renewal of CSCs, and arsenic trioxide (As2O3) has been reported to inhibit Gli1, a key transcription factor of Hedgehog pathway. In this study, we evaluated whether As2O3 has inhibitory effects on cancer stem-like cells (CSLCs) in lung cancer and further explored the possible mechanism. CCK8 assay and colony formation assay were performed to demonstrate the ability of As2O3 to inhibit the growth of NCI-H460 and NCI-H446 cells, which represented non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), respectively. Tumor sphere formation assay was carried out to evaluate the effects of As2O3 on stem cell-like subpopulations. The expression of stem cell biomarkers CD133 and stem cell transcription factors such as Sox2 and Oct4 were detected. Moreover, the effects of As2O3 on expression of Gli1 and its target genes were observed. We found that As2O3 inhibited the cell proliferation and reduced the colony formation ability. Importantly, As2O3 decreased the formation of tumor spheres. The expression of stem cell biomarker CD133 and stem cell transcription factors such as Sox2 and Oct4 were markedly reduced by As2O3 treatment. Furthermore, As2O3 decreased the expression of Gli1, N-myc and GAS1. Our results suggested that As2O3 is a promising agent to inhibit CSLCs in lung cancer. In addition, the mechanism of CSLCs inhibition might involve Gli1 down-regulation.

Efficacy of Arsenic Trioxide in the Treatment of Malignant Pleural Effusion Caused by Pleural Metastasis of Lung Cancer.

The aim of the study was to investigate the mechanism of arsenic trioxide (As2O3) in the treatment of malignant pleural effusion (MPE) caused by pleural metastasis of lung cancer. A mouse model of MPE caused by pleural metastasis of lung cancer was first established, and As2O3 was then intraperitoneally injected to treat the MPE. Mice treated with bevacizumab and bleomycin were included as positive controls, and placebo equivalents were also used as negative controls. The effects of As2O3 on MPE volume, pleural vessel density, vascular permeability, expression of angiogenic function-related factors, including vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-α), as well as nuclear factor-κB (NF-κB) activity in pleural carcinomatosis, were observed. Intraperitoneal injection of As2O3 reduced the volume of MPE and decreased vascular density and permeability in pleural metastatic nodules in a dose-dependent manner. Moreover, dose-dependent decreases in VEGF and TNF-α expression in MPE, and NF-κB activity in pleural carcinomatosis, were also found after As2O3 treatment. We showed that As2O3 can down-regulate VEGF expression via inhibition of NF-κB, and decrease vascular density and permeability in pleural metastatic nodules, thereby eliciting its effects on MPE caused by pleural metastasis of lung cancer. Our results provide a foundation for an As2O3-based clinical treatment program.