Bexarotene inhibits the viability of non-small cell lung cancer cells via slc10a2/PPARγ/PTEN/mTOR signaling pathway

Exploring the combined therapeutic efficacy of bexarotene and icariin in type 2 diabetic rats

OBJECTIVES

The aim of this study was to determine the single and combined antidiabetic activity and side effects of the retinoid X receptor agonist bexarotene and the thioredoxin-interacting protein inhibitor and peroxisome proliferator-activated receptor γ and AMP-activated protein kinase activator icariin.

METHODS

The rats were grouped as healthy (control), diabetes, diabetes + bexarotene (20 mg/kg), diabetes + icariin (60 mg/kg), diabetes + bexarotene (10 mg/kg) + icariin (30 mg/kg) low-dose combination and diabetes + bexarotene (20 mg/kg) + icariin (60 mg/kg) high-dose combination groups.

KEY FINDINGS

Icariin treatment led to a significant reduction in glucose levels compared with the diabetes control group, a remarkable outcome observed 45 days after the initial application. HbA1c levels of the icariin and low-dose combination treatment groups were significantly lower than in the diabetes group. Notably, icariin treatment also significantly elevated HOMA-β levels, which is indicative of improved β-cell function. Icariin significantly decreased glucose levels at 30 and 120 min in the oral glucose tolerance test. Moreover, it ameliorated hepatocyte degeneration, hepatic cord dissociation, congestion, mononuclear cell infiltration in the liver, and degeneration in the pancreas.

CONCLUSIONS

Icariin treatment exhibited robust antidiabetic effects with fewer side effects than other treatment options in this study. In future studies, long-term and varying doses of icariin will contribute to the development of novel antidiabetic drugs.

Dual function of activated PPARγ by ligands on tumor growth and immunotherapy

As one of the peroxisome-proliferator-activated receptors (PPARs) members, PPARγ is a ligand binding and activated nuclear hormone receptor, which is an important regulator in metabolism, proliferation, tumor progression, and immune response. Increased evidence suggests that activation of PPARγ in response to ligands inhibits multiple types of cancer proliferation, metastasis, and tumor growth and induces cell apoptosis including breast cancer, colon cancer, lung cancer, and bladder cancer. Conversely, some reports suggest that activation of PPARγ is associated with tumor growth. In addition to regulating tumor progression, PPARγ could promote or inhibit tumor immunotherapy by affecting macrophage differentiation or T cell activity. These controversial findings may be derived from cancer cell types, conditions, and ligands, since some ligands are independent of PPARγ activity. Therefore, this review discussed the dual role of PPARγ on tumor progression and immunotherapy.

Identification of hypoxia-related gene signatures based on multi-omics analysis in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common type of lung cancer and one of the malignancies with the highest incidence rate and mortality worldwide. Hypoxia is a typical feature of tumour microenvironment (TME), which affects the progression of LUAD from multiple molecular levels. However, the underlying molecular mechanisms behind LUAD hypoxia are not fully understood. In this study, we estimated the level of hypoxia by calculating a score based on 15 hypoxia genes. The hypoxia scores were relatively high in LUAD patients with poor prognosis and were bound up with tumour node metastasis (TNM) stage, tumour size, lymph node, age and gender. By comparison of high hypoxia score group and low hypoxia score group, 1820 differentially expressed genes were identified, among which up-regulated genes were mainly about cell division and proliferation while down-regulated genes were primarily involved in cilium-related biological processes. Besides, LUAD patients with high hypoxia scores had higher frequencies of gene mutations, among which TP53, TTN and MUC16 had the highest mutation rates. As for DNA methylation, 1015 differentially methylated probes-related genes were found and may play potential roles in tumour-related neurobiological processes and cell signal transduction. Finally, a prognostic model with 25 multi-omics features was constructed and showed good predictive performance. The area under curve (AUC) values of 1-, 3- and 5-year survival reached 0.863, 0.826 and 0.846, respectively. Above all, our findings are helpful in understanding the impact and molecular mechanisms of hypoxia in LUAD.

Effects of Modulation of the Hedgehog and Notch Signaling Pathways on Osteoblast Differentiation Induced by Titanium with Nanotopography

BACKGROUND

The events of bone formation and osteoblast/titanium (Ti) interactions may be affected by Hedgehog and Notch signalling pathways. Herein, we investigated the effects of modulation of these signalling pathways on osteoblast differentiation caused by the nanostructured Ti (Ti-Nano) generated by H₂SO₄/H₂O₂.

METHODS

Osteoblasts from newborn rat calvariae were cultured on Ti-Control and Ti-Nano in the presence of the Hedgehog agonist purmorphamine or antagonist cyclopamine and of the Notch antagonist N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) or agonist bexarotene. Osteoblast differentiation was evaluated by alkaline phosphatase activity and mineralization, and the expression of Hedgehog and Notch receptors was also evaluated.

RESULTS

In general, purmorphamine and DAPT increased while cyclopamine and bexarotene decreased osteoblast differentiation and regulated the receptor expression on both Ti surfaces, with more prominent effects on Ti-Nano. The purmorphamine and DAPT combination exhibited synergistic effects on osteoblast differentiation that was more intense on Ti-Nano.

CONCLUSION

Our results indicated that the Hedgehog and Notch signalling pathways drive osteoblast/Ti interactions more intensely on nanotopography. We also demonstrated that combining Hedgehog activation with Notch inhibition exhibits synergistic effects on osteoblast differentiation, especially on Ti-Nano. The uncovering of these cellular mechanisms contributes to create strategies to control the process of osseointegration based on the development of nanostructured surfaces.

A Ferroptosis-Related Gene Signature for Overall Survival Prediction and Immune Infiltration in Lung Squamous Cell Carcinoma

Background: Ferroptosis is associated with cancer initiation and progression. However, the molecular mechanism and prognostic value of ferroptosis-related genes in lung squamous cell carcinoma (LUSC) are poorly understood.

Methods: The mRNA expression profiles, methylation data, and clinical information of patients with LUSC were downloaded from TCGA and GEO database. Ferroptosis-related differentially expressed genes (DEGs) were identified between cancerous and non-cancerous tissues, and their prognostic value was systemically investigated by bioinformatic analyses.

Results: A ferroptosis-related gene signature (ALOX5, TFRC, PHKG2, FADS2, NOX1) was constructed using multivariate Cox regression analysis and represented as a risk score. Overall survival (OS) probability was significantly lower in the high-risk group than in the low-risk group (P<0.001), and receiver operating characteristic curve showed a good predictive capacity (AUC = 0.739). The risk score was an independent prognostic factor for LUSC. A nomogram was constructed to predict the OS probabilities at 1, 3, and 5 years. High-risk score was associated with increased immune infiltration, lower methylation levels, higher immune checkpoint genes expression levels, and better chemotherapy response. Cell adhesion molecules, focal adhesion, and extracellular matrix receptor interaction were the main pathways in the high-risk group. The signature was validated using the TCGA test cohort, entire TCGA cohort, GSE30219, GSE157010, GSE73403, and GSE4573 datasets. The gene disorders in patients with LUSC were validated using real-time PCR and single-cell RNA sequencing analysis.

Conclusions: A ferroptosis-related gene signature was constructed to predict OS probability in LUSC. This could facilitate novel therapeutic methods and guide individualized therapy.

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

Role of hemoglobin alpha and hemoglobin beta in non-small-cell lung cancer based on bioinformatics analysis

The differentially expressed genes (DEGs) were identified and screened differentially in non-small-cell lung cancer (NSCLC) using information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus databases, and the correlation of DEGs in protein interaction, function, and pathway enrichment were analyzed to search for new biomarkers and potential therapeutic targets for NSCLC. Protein-protein interaction network (PPI) analysis showed that CDK1 and GNGT1 were the most significantly upregulated hub nodes, while FPR2 was the most significantly downregulated. Gene Ontology enrichment analysis showed that upregulated DEGs were significantly enriched in protein heterodimerization activity and other functions, while downregulated DEGs were enriched in functions such as heparin-binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that upregulation of DEGs were significantly associated with neuroactive ligand-receptor interaction pathways, while downregulation of DEGs were significantly associated with malaria pathways. According to the analysis results, we identified hemoglobin alpha (HBA) and hemoglobin beta (HBB) as the genes of interest for further study. Through tissue level and cell level experiments, we found that the expressions of HBA and HBB in NSCLC tissues were significantly lower than those in paracancerous tissues, and downregulation of HBA and HBB could significantly affect the proliferation ability of NSCLC cells. In addition, we also found that changes in HBA and HBB may affect NSCLC cells through the p38/MAPK pathway and JNK pathway, and ultimately affect the occurrence and development of NSCLC.

Role of Small Molecule Targeted Compounds in Cancer: Progress, Opportunities, and Challenges

Research on molecular targeted therapy of tumors is booming, and novel targeted therapy drugs are constantly emerging. Small molecule targeted compounds, novel targeted therapy drugs, can be administered orally as tablets among other methods, and do not draw upon genes, causing no immune response. It is easily structurally modified to make it more applicable to clinical needs, and convenient to promote due to low cost. It refers to a hotspot in the research of tumor molecular targeted therapy. In the present study, we review the current Food and Drug Administration (FDA)-approved use of small molecule targeted compounds in tumors, summarize the clinical drug resistance problems and mechanisms facing the use of small molecule targeted compounds, and predict the future directions of the evolving field.

Induction of G2/M Cell Cycle Arrest via p38/p21Waf1/Cip1-Dependent Signaling Pathway Activation by Bavachinin in Non-Small-Cell Lung Cancer Cells

Lung cancer is the most commonly diagnosed malignant cancer in the world. Non-small-cell lung cancer (NSCLC) is the major category of lung cancer. Although effective therapies have been administered, for improving the NSCLC patient’s survival, the incident rate is still high. Therefore, searching for a good strategy for preventing NSCLC is urgent. Traditional Chinese medicine (TCM) are brilliant materials for cancer chemoprevention, because of their high biological safety and low cost. Bavachinin, which is an active flavanone of Proralea corylifolia L., possesses anti-inflammation, anti-angiogenesis, and anti-cancer activities. The present study’s aim was to evaluate the anti-cancer activity of bavachinin on NSCLC, and its regulating molecular mechanisms. The results exhibited that a dose-dependent decrease in the cell viability and colony formation capacity of three NSCLC cell lines, by bavachinin, were through G2/M cell cycle arrest induction. Meanwhile, the expression of the G2/M cell cycle regulators, such as cyclin B, p-cdc2^Y15, p-cdc2^T161, and p-wee1, was suppressed. With the dramatic up-regulation of the cyclin-dependent kinase inhibitor, p21^Waf1/Cip1, the expression and association of p21^Waf1/Cip1 with the cyclin B/cdc2 complex was observed. Silencing the p21^Waf1/Cip1 expression significantly rescued bavachinin-induced G2/M cell accumulation. Furthermore, the expression of p21^Waf1/Cip1 mRNA was up-regulated in bavachinin-treated NSCLC cells. In addition, MAPK and AKT signaling were activated in bavachinin-added NSCLC cells. Interestingly, bavachinin-induced p21^Waf1/Cip1 expression was repressed after restraint p38 MAPK activation. The inhibition of p38 MAPK activation reversed bavachinin-induced p21^Waf1/Cip1 mRNA expression and G2/M cell cycle arrest. Collectively, bavachinin-induced G2/M cell cycle arrest was through the p38 MAPK-mediated p21^Waf1/Cip1-dependent signaling pathway in the NSCLC cells.

Anticancer effects of dihydromyricetin on the proliferation, migration, apoptosis and in vivo tumorigenicity of human hepatocellular carcinoma Hep3B cells

Background

Hepatocellular carcinoma (HCC) represents a serious public health problem worldwide and has high morbidity and mortality. Dihydromyricetin (DHM) exhibits anticancer effect on a variety of malignancies, but its anticancer function of DHM in HCC has been unclear. The aim of this study was designed to investigate the anticancer effect of DHM on cell apoptosis, proliferation, migration and invasion of hepatoma carcinoma cells.

Methods

Cultured Hep3B cells were treated with different DHM concentrations, followed by cell apoptosis, proliferation, migration and invasion were examined by CCK-8, colony formation assay, wound healing, Transwell and flow cytometry, respectively. The mRNA and protein expression of BCL-2, Cleaved-caspase 3, Cleaved-caspase 9, BAK, BAX and BAD were validated by western blot.

Results

DHM markedly suppressed proliferation, migration, invasion and facilitated apoptosis in Hep3B cells. Mechanistically, DHM significantly downregulated the Bcl-2 expression, and upregulated the mRNA and protein levels of Cleaved-Caspase 3, Cleaved- Caspase 9, Bak, Bax and Bad. Furthermore, in the nude mice tumorigenic model, DHM treatment greatly decreased the weight of the HCC cancers compared to the weights in control and NDP group.

Conclusions

DHM could suppress cell proliferation, migration, invasion, and facilitated apoptosis in Hep3B cells. These findings could provide novel insights to develop potential therapeutic strategy for the clinical treatment of HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03356-5.

Targeting the TR4 nuclear receptor with antagonist bexarotene can suppress the proopiomelanocortin signalling in AtT-20 cells

Drug options for the life‐threatening Cushing's disease are limited, and surgical resection or radiation therapy is not invariably effective. Testicular receptor 4 (TR4) has been identified as a novel drug target to treat Cushing's disease. We built the structure model of TR4 and searched the TR4 antagonist candidate via in silico virtual screening. Bexarotene was identified as an antagonist of TR4 that can directly interact with TR4 ligand binding domain (TR4‐LBD) and induces a conformational change in the secondary structure of TR4‐LBD. Bexarotene suppressed AtT‐20 cell growth, proopiomelanocortin (POMC) expression and adrenocorticotropin (ACTH) secretion. Mechanism dissection revealed that bexarotene could suppress TR4‐increased POMC expression via promoting the TR4 translocation from the nucleus to the cytoplasm. This TR4 translocation might then result in reducing the TR4 binding to the TR4 response element (TR4RE) on the 5’ promoter region of POMC. Results from in vivo mouse model also revealed that oral bexarotene administration markedly suppressed ACTH‐secreting tumour growth, adrenal enlargement and the secretion of ACTH and corticosterone in mice with already established tumours. Together, these results suggest that bexarotene may be developed as a potential novel therapeutic drug to better suppress Cushing's disease.

A Novel Co-Crystal of Bexarotene and Ligustrazine Improves Pharmacokinetics and Tissue Distribution of Bexarotene in SD Rats

Bexarotene (BEX), a specific retinoic acid X receptor (RXR) agonist granted by Food and Drug Administration (FDA) approval for the clinical treatment of T cell lymphoma, has now been found to exert pharmacological effects in the nervous system, with low bioavailability and poor cerebral distribution limiting its application in treatment on neurological disorders. Pharmaceutical co-crystal was a helpful method to improve the bioavailability and tissue distribution of active pharmaceutical ingredients (APIs). Here, 2bexarotene-ligustrazine (2BEX-LIG), a novel co-crystal system of BEX and ligustrazine (LIG) of which with BEX is an API, was constructed with satisfactory stability and enhanced solubility. The pharmacokinetics characteristics of BEX were detected, and the results showed that the absolute bioavailability and the cerebral concentration of BEX in rats administrated with 2BEX-LIG were enhanced from 22.89% to 42.86% and increased by 3.4-fold, respectively, compared with those in rats administrated an equivalent of BEX. Hence, our present study indicated that the novel co-crystal of 2BEX-LIG contributed to improving BEX oral bioavailability and cerebral distribution, thereby providing significant advantages for clinical application of brain tumors and other neurological diseases.

Development of an Immune-Related Risk Signature for Predicting Prognosis in Lung Squamous Cell Carcinoma

Lung squamous cell carcinoma (LSCC) is the most common subtype of non-small cell lung cancer. Immunotherapy has become an effective treatment in recent years, while patients showed different responses to the current treatment. It is vital to identify the potential immunogenomic signatures to predict patient' prognosis. The expression profiles of LSCC patients with the clinical information were downloaded from TCGA database. Differentially expressed immune-related genes (IRGs) were extracted using edgeR algorithm, and functional enrichment analysis showed that these IRGs were primarily enriched in inflammatory- and immune-related processes. "Cytokine-cytokine receptor interaction" and "PI3K-AKT signaling pathway" were the most enriched KEGG pathways. 27 differentially expressed IRGs were significantly correlated with the overall survival (OS) of patients using univariate Cox regression analysis. A prognostic risk signature that comprises seven IRGs (GCCR, FGF8, CLEC4M, PTH, SLC10A2, NPPC, and FGF4) was developed with effective predictive performance by multivariable Cox stepwise regression analysis. Most importantly, the signature could be an independent prognostic predictor after adjusting for clinicopathological parameters, and also validated in two independent LSCC cohorts (GSE4573 and GSE17710). Potential molecular mechanisms and tumor immune landscape of these IRGs were investigated through computational biology. Analysis of tumor infiltrating lymphocytes and immune checkpoint molecules revealed distinct immune landscape in high- and low-risk group. The study was the first time to construct IRG-based immune signature in the recognition of disease progression and prognosis of LSCC patients.

Novel bexarotene derivatives: Synthesis and cytotoxicity evaluation for glioma cells in 2D and 3D in vitro models

Glioblastoma (GBM) is an aggressive and lethal form of brain cancer with a high invasion capacity and a lack of effective chemotherapeutics. Retinoid bexarotene (BXR) inhibits the neurospheroidal colony formation and migration of primary glioblastoma cells but has side effects. To enhance the BXR glioblastoma selectivity and cytotoxicity, we chemically modified it at the carboxyl group with either nitroethanolamine (NEA) bearing a NO-donating group (a well-known bioactivity enhancer; BXR-NEA) or with a dopamine (DA) moiety (to represent the highly toxic for various tumor cells N-acyldopamine family; BXR-DA). These two novel compounds were tested in the 2D (monolayer culture) and 3D (multicellular tumor spheroids) in vitro models. Both BXR-DA and BXR-NEA were found to be more toxic for rat C6 and human U-87MG glioma cells than the initial BXR. After 24 h incubation of the cells (monolayer culture) with the drugs, the IC₅₀ values were in the range of 28-42, and 122-152 μM for BXR derivatives and BXR, respectively. The cell death occurred via apoptosis according to the annexin staining and caspase activation. The tumor spheroids demonstrated higher resistance to the treatment compared to that one of the monolayer cultures. BXR-DA and BXR-NEA were more specific against tumor cells than the parental drug, in particular the selectivity index was 1.8-2.7 vs. 1.3-1.5, respectively. Moreover, they inhibited cell migration more effectively than parental BXR according to a scratch assay. Cell spreading from the tumor spheroids was also inhibited. Thus, the obtained BXR derivatives could be promising for glioblastoma treatment.

Prediction and identification of immune genes related to the prognosis of patients with colon adenocarcinoma and its mechanisms

Background

Colon adenocarcinoma (COAD) is a gastrointestinal tumor with a high degree of malignancy. Its deterioration process is closely related to the tumor microenvironment, and transcription factors (TF) play a regulatory role in this process. Currently, there is a lack of exploration between the genes related to the COAD tumor microenvironment and the survival prognosis of patients. Models composed of multiple genes usually predict the survival prognosis of patients more accurately than single genes. We can analyze the multigene models that can predict the prognosis of COAD from the current database.

Methods

The limma package of the R programming language is used for gene differential expression analysis. Kaplan-Meier curve is used to analyze the relationship between the patient risk score model and survival data. The hazard model is used to analyze the relationship between the risk score and the clinical data of COAD patients. The information of immune genes and immune cells is obtained from IMMPORT database and TIMER database. Receiver operating characteristic (ROC) curve is used to judge the stability of the model.

Results

We found 7 immune genes, which can built a risk score model to predict the survival prognosis of COAD. According to univariate and multivariate analysis, the risk score can be used as an independent predictor. The content of some immune microenvironment cells will also increase as the risk score increases.

Conclusions

We found 7 immune genes, such as SLC10A2 (solute carrier family 10 member 2), CXCL3 (C-X-C motif chemokine ligand 3), IGHV5-51 (immunoglobulin heavy variable 5-51), INHBA (inhibin subunit beta A), STC1 (stanniocalcin 1), UCN (urocortin), and OXTR (oxytocin receptor), can constitute a model for predicting the prognosis of COAD. They may provide potential therapeutic targets for clinical treatment of COAD.

Long Noncoding RNA KCNQ1OT1 Promotes the Progression of Non-Small Cell Lung Cancer via Regulating miR-204-5p/ATG3 Axis

Purpose

Non-small cell lung cancer (NSCLC) is the first leading cause of cancer-related death globally. Long noncoding RNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) was involved in the progression of multiple cancers by sponging target miRNA. We aimed to explore the pathological mechanism of KCNQ1OT1 in NSCLC progression.

Methods

The expression of KCNQ1OT1, miR-204-5p and autophagy-related gene 3 (ATG3) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry assay were conducted for the detection of cell proliferation and apoptosis, respectively. Western blot assay was performed to examine the protein levels of B-cell lymphoma-2 (BCL-2), BCL2-Associated X (Bax), cleaved caspase-3, cleaved caspase-9 and LC3Ⅱ/LC3Ⅰ and P62. The interaction between miR-204-5p and KCNQ1OT1 or ATG3 was validated by dual-luciferase reporter system and RNA immunoprecipitation (RIP) assay. Murine xenograft assay was conducted to explore the function of KCNQ1OT1 in vivo. Immunohistochemistry (IHC) staining assay was used for the analysis of ki67-positive cell percentage.

Results

The expression of KCNQ1OT1 and ATG3 was up-regulated whereas miR-204-5p was down-regulated in NSCLC tumors and cells. MiR-204-5p was inversely correlated with KCNQ1OT1 or ATG3. In addition, KCNQ1OT1 knockdown facilitated apoptosis, inhibited autophagy and proliferation of NSCLC cells in vitro and blocked tumor growth in vivo. However, the miR-204-5p inhibitor reversed the effects. More importantly, ATG3 was a target gene of miR-204-5p and ATG3 overexpression restored the effect of miR-204-5p on NSCLC cell progression.

Conclusion

KCNQ1OT1 promotes cell proliferation and autophagy and inhibits cell apoptosis via regulating miR-204-5p/ATG3 axis, providing a promising target for NSCLC therapy.

lncRNA ZEB2-AS1 Aggravates Progression of Non-Small Cell Lung Carcinoma via Suppressing PTEN Level

Background

The aim of this study was to assess the involvement of lncRNA ZEB2-AS1 in the development of NSCLC and to explore the potential mechanism involved.

Material/Methods

ZEB2-AS1 expressions in 48 paired NSCLC tissues and paracancerous tissues were examined by qRT-PCR. ZEB2-AS1 level in NSCLC patients affected by tumor staging and lymphatic metastasis was examined as well. Regulatory effects of ZEB2-AS1 on proliferative, migratory, and invasive properties of NCI-H1650 and HCC827 cells were evaluated. The interaction between ZEB2-AS1 and EZH2 was identified through RIP assay. Subsequently, the binding of EZH2 on PTEN promoter region was tested by ChIP. Finally, rescue experiments were conducted to assess the involvement of PTEN in the development of NSCLC.

Results

ZEB2-AS1 was upregulated in NSCLC tissues and cell lines. Its level was higher in NSCLC patients with T3–T4 or accompanied with lymphatic metastasis relative to those with T1–T2 or without metastatic loci. Knockdown of ZEB2-AS1 suppressed proliferative, migratory, and invasive properties of NCI-H1650 and HCC827 cells. PTEN level was elevated after knockdown of ZEB2-AS1 or EZH2 in HCC827 cells. Subsequently, RIP assay proved the interaction between ZEB2-AS1 and EZH2. Knockdown of ZEB2-AS1 markedly reduced the binding of EZH2 on the PTEN promoter region. Notably, knockdown of PTEN reversed the effects of EZB2-AS1 on regulating proliferative, migratory, and invasive properties of NSCLC cells.

Conclusions

lncRNA ZEB2-AS1 is upregulated in NSCLC, which elevates the viability and malignant degree of NSCLC cells by downregulating PTEN, thus aggravating the progression of NSCLC.

Serum starvation induces cell death in NSCLC via miR-224

Purpose: Increasing evidence suggests that microRNAs (miRNAs) may be involved in the occurrence and progression of non-small cell lung cancer (NSCLC). In the present study, we used serum-starved A549 cells emulating tumor under a nutrient depletion stress in the microenvironment.

Patients and methods: We first detected the expression level of miR-224 between tumor tissues and the adjacent normal tissues. We analyzed the expression levels of miR-224 and its predicted target phosphatase and tensin homolog (PTEN) using quantitative real-time PCR (qRT-PCR) in starved A549 cells. Following transfection with miR-224 mimic or inhibitor in starved A549 cells, MTT assay, Annexin V FITC/PI staining, and LC-3 immunofluorence staining were performed to investigate the roles of miR-224 on proliferation, apoptosis, and autophagy. Next, the expression of apoptosis-related protein Bax and Bcl-2, autophagy-related proteins LC3, PI3K signaling, and target PTEN were measured using qRT-PCR and Western blot assays. The direct interaction between miR-224 and PTEN was validated with a dual luciferase assay.

Results: We found that the expression level of miR-224 in tumor tissues was significantly higher when compared with the adjacent normal tissues. We discovered a reciprocal expression pattern between miR-224 and PTEN in starved A549 cells, and transfection with miR-224 mimic led to down-regulation of PTEN. A dual luciferase assay further confirmed the direct interaction between miR-224 and 3ʹUTR of PTEN. Transfection with miR-224 mimic in starved A549 cells resulted in enhanced cell proliferation, reduced apoptosis, and autophagy, accompanied by increased expression of anti-apoptotic protein Bcl-2, decreased expression of pro-apoptotic protein Bax, and autophagy-related protein LC3. Activation of PI3K was observed in miR-224 mimic transfected cells. The reverse effects by the miR-224 inhibitor in all experiments were observed.

Conclusion: Taken together, we proved that miR-224 might play essential roles in cellular functions of nutrient-depleted A549 cells possibly through regulating the target PTEN and downstream signal PI3K, suggesting the potential of miR-224 to be a therapeutic target for NSCLC therapy.

Optimized Bexarotene Aerosol Formulation Inhibits Major Subtypes of Lung Cancer in Mice

Bexarotene has shown inhibition of lung and mammary gland tumorigenesis in preclinical models and in clinical trials. The main side effects of orally administered bexarotene are hypertriglyceridemia and hypercholesterolemia. We previously demonstrated that aerosolized bexarotene administered by nasal inhalation has potent chemopreventive activity in a lung adenoma preclinical model without causing hypertriglyceridemia. To facilitate its future clinical translation, we modified the formula of the aerosolized bexarotene with a clinically relevant solvent system. This optimized aerosolized bexarotene formulation was tested against lung squamous cell carcinoma mouse model and lung adenocarcinoma mouse model and showed significant chemopreventive effect. This new formula did not cause visible signs of toxicity and did not increase plasma triglycerides or cholesterol. This aerosolized bexarotene was evenly distributed to the mouse lung parenchyma, and it modulated the microenvironment in vivo by increasing the tumor-infiltrating T cell population. RNA sequencing of the lung cancer cell lines demonstrated that multiple pathways are altered by bexarotene. For the first time, these studies demonstrate a new, clinically relevant aerosolized bexarotene formulation that exhibits preventive efficacy against the major subtypes of lung cancer. This approach could be a major advancement in lung cancer prevention for high risk populations, including former and present smokers.

Bexarotent Attenuated Chronic Constriction Injury-Induced Spinal Neuroinflammation and Neuropathic Pain by Targeting Mitogen-Activated Protein Kinase Phosphatase-1

It is widely accepted that neuroinflammation in the spinal cord contributes to the development of central sensitization in neuropathic pain. Mitogen-activated protein kinase (MAPK) activation plays a vital role in the development of neuroinflammation in the spinal cord. In this study, we investigated the effect of bexarotene (bex), a retinoid X receptor agonist, on MAPKs activation in chronic constriction injury (CCI)-induced neuropathic pain. The data showed that daily treatment with bex 50 mg/kg significantly alleviated CCI-induced nociceptive hypersensitivity in rats. Bex 50 mg/kg/day inhibited CCI-induced MAPKs (p38MAPK, ERK1/2, and JNK) activation and upregulation of proinflammatory factors (IL-1β, tumor necrosis factor-α and IL-6). Bex also reversed CCI-induced microglia activation in the ipsilateral spinal cord. Furthermore, bex treatment significantly upregulated MKP-1 in the spinal cord. These effects were completely abrogated by MKP-1 inhibitor BCI. These results indicated that bex relieved CCI-induced neuroinflammation and neuropathic pain by targeting MKP-1. Therefore, bex might be a potential agent for the treatment of neuropathic pain. PERSPECTIVE: Bex could relieve neuropathic pain behaviors in animals by reversing MKP-1 downregulation and MAPKs activation in the spinal cord. Therapeutic applications of bex may be extended beyond cutaneous T-cell lymphoma.

Inhibition of microRNA‑939 suppresses the development of human non‑small cell lung cancer via the upregulation of tissue inhibitor of metalloproteinases 2

Numerous microRNAs (miRNA/miRs) have been reported to be associated with the initiation and progression of non‑small cell lung cancer (NSCLC). The aim of the present study was to examine the expression and biological role of miR‑939 in human NSCLC, in vitro. Reverse transcription‑quantitative polymerase chain reaction analysis was used to evaluate the expression of miR‑939 in NSCLC tissues. Cell Counting Kit‑8, 5‑ethynyl‑29‑deoxyuridine and Transwell assays were also used to determine the effects of miR‑939 on tumor cell proliferation and invasion in two human NSCLC cell lines (H1299 and SPCA1). Furthermore, tissue inhibitor of metalloproteinases 2 (TIMP2) was confirmed to be a target of miR‑939 by luciferase reporter assay, western blotting and bioinformatics analysis. Following downregulation of miR‑939 expression, cell proliferative and invasive abilities were significantly suppressed. Collectively, these findings indicated that the knockdown of miR‑939 may inhibit cell proliferation and invasion by regulating the expression of TIMP2 in NSCLC cells. Thus, miR‑939 may be a potential target in the treatment of NSCLC, although this requires further investigation.

Silencing the FOLR2 Gene Inhibits Cell Proliferation and Increases Apoptosis in the NCI-H1650 Non-Small Cell Lung Cancer Cell Line via Inhibition of AKT/Mammalian Target of Rapamycin (mTOR)/Ribosomal Protein S6 Kinase 1 (S6K1) Signaling

Background

The FOLR2 gene encodes folate receptor-beta (FR-beta), which is expressed by tumor-associated macrophages. The effects of FOLR2 gene expression in non-small cell lung cancer (NSCLC) remains unknown. This study aimed to investigate the effects of FOLR2 gene expression and gene silencing in human NSCLC cell lines and normal human bronchial epithelial (HBE) cells in vitro.

Material/Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect the expression of the FOLR2 gene, cell cycle and apoptosis-associated genes in normal HBE cells and the NSCLC cell lines, A549, NCI-H1299, NCI-H1650, and NCI-H460. Using small interfering RNA (siRNA), or silencing RNA, FOLR2 gene silencing was performed for NCI-H1650 cells. Cell counting kit-8 (CCK-8) was used to measure cell viability. Cell cycle and apoptosis were determined using flow cytometry. Western blot evaluated the expression of Akt, mTOR, and S6K1 signaling.

Results

Expression of the FOLR2 gene was increased in NSCLC cells compared with normal HBE cells. Silencing of the expression of the FOLR2 gene in NCI-H1650 cells reduced cell viability, increased cell apoptosis, and arrested cells in the G1 phase of the cell cycle, decreased the expression of cyclin D1, upregulated expression of cell cycle inhibitors, p21 and p27, upregulated the expression of Bax/Bcl-2, and inhibited phosphorylation of AKT, mTOR, and S6K1.

Conclusions

Silencing of the FOLR2 gene inhibited phosphorylation of AKT, mTOR, and S6K1, inhibited cell proliferation and increased apoptosis in the NCI-H1650 human NSCLC cell line.