Sulfate Aerosols Promote Lung Cancer Metastasis by Epigenetically Regulating the Epithelial-to-Mesenchymal Transition (EMT)

Metastatic effects of hydroxy-polycyclic aromatic hydrocarbons on liver cancer cells mediated by estrogen receptor α

Hydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) are a growing worldwide concern because of their persistence, ubiquity, and toxicity. Nonetheless, research on the toxicological mechanisms of OH-PAHs remains sparse, particularly concerning the risk of liver cancer. This study evaluated the effects of OH-PAHs on disrupting estrogen receptor α (ERα) and subsequently facilitating hepatocellular invasion and metastasis. Results revealed that all six OH-PAHs exhibited ERα agonistic activities at noncytotoxic levels, which were partially validated using molecular docking (MD) and molecular dynamics simulations (MDS). Furthermore, OH-PAHs with ERα agonistic properties stimulated a concentration-dependent increase in the migration and invasion of HepG2 cells. In addition, they disturbed the expression of target genes associated with epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM), and the invasion effects were significantly reversed by adding an ERα antagonist. Our results suggest an essential role of ERα in the metastasis of liver cancer cells induced by OH-PAHs and emphasize their potential ecological and health hazards.

Nontargeted Identification of Organic Components in Fine Particulate Matter Related to Lung Tumor Metastasis Based on an Adverse Outcome Pathway Strategy

Emerging studies implicate fine particulate matter (PM2.5) and its organic components (OCs) as urgent hazard factors for lung cancer progression in nonsmokers. Establishing the adverse outcome pathway (AOP)-directed nontargeted identification method, this study aimed to explore whether PM2.5 exposure in coal-burning areas promoted lung tumor metastasis and how we identify its effective OCs to support traceability and control of regional PM2.5 pollution. First, we used a nude mouse model of lung cancer for PM2.5 exposure and found that the exposure significantly promoted the hematogenous metastases of A549-Luc cells in lung tissues and the adverse outcomes (AOs), with key events (KEs) including the changed expression of epithelial-mesenchymal transition (EMT) markers, such as suppression of E-cad and increased expression of Fib. Subsequently, using AOs and KEs as adverse outcome directors, we identified a total of 35 candidate chemicals based on the in vitro model and nontargeted analysis. Among them, tributyl phosphate (C12H27O4P), 2-bromotetradecane (C14H29Br), and methyl decanoate (C11H22O2) made greater contributions to the AOs. Finally, we clarified the interactions between these OCs and EMT-activating transcription factors (EMT-ATFs) as the molecular initiation event (MIE) to support the feasibility of the above identification strategy. The present study updates a new framework for identifying tumor metastasis-promoting OCs in PM2.5 and provides solid data for screening out chemicals that need priority control in polluted areas posing higher lung cancer risk.

The biomarkers associated with epithelial-mesenchymal transition in human keloids

INTRODUCTION

A keloid is a type of benign fibrotic disease with similar features to malignancies, including anti-apoptosis, over-proliferation, and invasion. Epithelial-mesenchymal transition (EMT) is a crucial mechanism that regulates the metastatic behavior of tumors. Thus, identifying EMT biomarkers is paramount in comprehensively understanding keloid pathogenesis.

METHODS

To identify the differentially expressed genes (DEGs) GSE92566 dataset, with 3 normal skin and 4 keloid tissues, was downloaded from GEO databases to identify the differentially expressed genes (DEGs). Further, EMT-related genes were downloaded from dbEMT 2.0 databases and intersected with GSE92566 DEGs to identify EMT-related-DEGs (ERDEGs). Subsequently, the ERDEGs were used for GO, KEGG, gene set enrichment analysis (GSEA), protein-protein interaction (PPI), and miRNAs-mRNAs network analysis. To predict small molecules for EMT inhibition, the ERDEGs were imported to cMAP databases, whereas hub genes were imported to DGidb databases. Finally, we carried out qRT-PCR and in vitro experiments to validate our findings.

RESULTS

A total of 122 ERDEGs were identified, including 59 upregulated and 63 down-regulated genes. Moreover, enrichment analysis revealed that focal adhesion, AMPK signal pathway, Wnt signal pathway, and EMT biological process were significantly enriched. STRING databases and Cytoscape software were used to construct the PPI network and EMT-related hub genes. Further, 3 modules were explored from the PPI network using the Molecular Complex Detection (MCODE) plugin. In the Cytohubba plugin, 10 hub genes were explored, including FN1, EGF, SOX9, CDH2, PROM1, EPCAM, KRT19, ITGB1, CD24, and KRT18. These genes were then enriched for the focal adhesion pathway. We constructed a microRNA (miRNA)-mRNA network, which predicted hsa-miR-155-5p (8 edges), hsa-miR-124-3p (7 edges), hsa-miR-145-5p (5 edges), hsa-miR-20a-5p (5 edges) and hsa-let-7b-5p (4 edges) as the most connected miRNAs regulating EMT. Based on the ERDEGs and 10 hub genes mentioned above, ribavirin demonstrated high drug-targeting relevance. Subsequently, qRT-PCR confirmed that the expression of FN1, ITGB1, CDH2, and EPCAM corroborated with previous findings. qRT-PCR also showed that the expression levels of hsa-miR-124-3p and hsa-miR-145-5p were significantly lower in keloids and hsa-miR-155-5p was upregulated in keloids. Finally, by treating human keloid fibroblasts (HKFs) with ribavirin in vitro, we confirmed that ribavirin could inhibit HKFs proliferation and EMT.

CONCLUSION

In summary, this work provides novel EMT biomarkers in keloids and predicts new small target molecules for keloid therapy. Our findings improve the understanding of keloid pathogenesis, providing new treatment options.

Metabolic regulation of tumor cells exposed to different oxygenated polycyclic aromatic hydrocarbons

Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are a class of polycyclic aromatic derivatives with oxygen-containing functional groups that induce oxidative stress and mutations. However, studies of the carcinogenic and metabolic effects of OPAHs are limited. In this study, we analyzed the carcinogenic effects of four different OPAHs and found that 9-fluorenone (FLO), 9,10-anthraquinone (AQ), and 7,12-benz(a)anthraquinone (BAQ) promoted cell invasion and metastasis via epithelial-mesenchymal transition (EMT) and induced endothelial cell angiogenesis by affecting the expression of vascular endothelial growth factor (VEGF), angiopoietin (ANG), and platelet-derived growth factor (PDGF), whereas 1,8-naphthalic anhydride (NAD) did not show significant carcinogenic effects. In addition, combined with metabolomic analysis, we found that the tumor-promoting effects of different OPAHs were related to their effects on the metabolome, especially the metabolism of glutathione related to oxidative stress. These results provide an experimental basis for studying the carcinogenic and metabolic effects of OPAHs, and an important reference for comprehensively assessing the ecological and health risks of this compounds.

Toxicological Effects of Secondary Air Pollutants

Secondary air pollutants, originating from gaseous pollutants and primary particulate matter emitted by natural sources and human activities, undergo complex atmospheric chemical reactions and multiphase processes. Secondary gaseous pollutants represented by ozone and secondary particulate matter, including sulfates, nitrates, ammonium salts, and secondary organic aerosols, are formed in the atmosphere, affecting air quality and human health. This paper summarizes the formation pathways and mechanisms of important atmospheric secondary pollutants. Meanwhile, different secondary pollutants' toxicological effects and corresponding health risks are evaluated. Studies have shown that secondary pollutants are generally more toxic than primary ones. However, due to their diverse source and complex generation mechanism, the study of the toxicological effects of secondary pollutants is still in its early stages. Therefore, this paper first introduces the formation mechanism of secondary gaseous pollutants and focuses mainly on ozone's toxicological effects. In terms of particulate matter, secondary inorganic and organic particulate matters are summarized separately, then the contribution and toxicological effects of secondary components formed from primary carbonaceous aerosols are discussed. Finally, secondary pollutants generated in the indoor environment are briefly introduced. Overall, a comprehensive review of secondary air pollutants may shed light on the future toxicological and health effects research of secondary air pollutants.

GB7 acetate, a galbulimima alkaloid from Galbulimima belgraveana, possesses anticancer effects in colorectal cancer cells

GB7 acetate is a galbulimima alkaloid obtained from Galbulimima belgraveana. However, information regarding its structure, biological activities, and related mechanisms is not entirely available. A series of spectroscopic analyses, structural degradation, interconversion, and crystallography were performed to identify the structure of GB7 acetate. The MTT assay was applied to measure cell proliferation on human colorectal cancer HCT 116 cells. The expressions of the related proteins were measured by Western blotting. Transmission electron microscopy (TEM), acridine orange (AO) and monodansylcadaverine (MDC) staining were used to detect the presence of autophagic vesicles and autolysosomes. A transwell assay was performed to demonstrate metastatic capabilities. Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) assays were performed to determine the mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis activity of HCT 116 cells. The data showed that GB7 acetate suppressed the proliferation and colony-forming ability of HCT 116 cells. Pretreatment with GB7 acetate significantly induced the formation of autophagic vesicles and autolysosomes. GB7 acetate upregulated the expressions of LC3 and Thr172 phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase α (p-AMPKα), which are key elements of autophagy. In addition, GB7 acetate suppressed the metastatic capabilities of HCT 116 cells. Additionally, the production of matrix metallo-proteinase-2 (MMP-2) and MMP-9 was reduced, whereas the expression of E-cadherin (E-cad) was upregulated. Furthermore, GB7 acetate significantly reduced mitochondrial OXPHOS and glycolysis. In conclusion, the structure of the novel Galbulimima alkaloid GB7 acetate was identified. GB7 acetate was shown to have anti-proliferative, pro-autophagic, anti-metastatic, and anti-metabolite capabilities in HCT 116 cells. This study might provide new insights into cancer treatment efficacy and cancer chemoprevention.

Black phosphorus conjugation of chemotherapeutic ginsenoside Rg3: enhancing targeted multimodal nanotheranostics against lung cancer metastasis

It is a significant challenge in lung cancer chemophotothermal (CPT) therapy to develop multifunctional theranostic nanoagent (MTN) for precise targeting and successful tumor treatments, especially for lung metastasis. To overcome this problem, we effectively design and construct multifunctional black phosphorus (BP) nanoagents, BPs/G-Rg3@PLGA. BPs quantum dots (BPsQDs) are co-loaded onto poly(lactic-co-glycolic acid) (PLGA) with subsequent conjugations of a cancer therapeutic compound, ginsenoside Rg3 (G-Rg3), in this composite nanoagent. The in vivo delivery findings suggest that BPs/G-Rg3@PLGA has an excellent affinity for primary tumors and metastatic lung tumors. Furthermore, when paired with near-light irradiation, BPs/G-Rg3@PLGA shows superior controllable CPT therapy synergetic therapeutics, significantly increasing photothermal tumor ablation effectiveness. Mechanistically, heating causes rapid G-Rg3 release from the non-complex, and thermal therapy induces apoptosis, culminating in the reduction of lung cancer metastasis. Additionally, in vivo and in vitro findings support the biocompatibility of BPs/G-Rg3@PLGA. This thesis identifies a versatile BPs-based MTN for lung cancer metastasis control.

Dual Role of Reactive Oxygen Species and their Application in Cancer Therapy

Reactive oxygen species (ROS) play a dual role in the initiation, development, suppression, and treatment of cancer. Excess ROS can induce nuclear DNA, leading to cancer initiation. Not only that, but ROS also inhibit T cells and natural killer cells and promote the recruitment and M2 polarization of macrophages; consequently, cancer cells escape immune surveillance and immune defense. Furthermore, ROS promote tumor invasion and metastasis by triggering epithelial-mesenchymal transition in tumor cells. Interestingly, massive accumulation of ROS inhibits tumor growth in two ways: (1) by blocking cancer cell proliferation by suppressing the proliferation signaling pathway, cell cycle, and the biosynthesis of nucleotides and ATP and (2) by inducing cancer cell death via activating endoplasmic reticulum stress-, mitochondrial-, and P53- apoptotic pathways and the ferroptosis pathway. Unfortunately, cancer cells can adapt to ROS via a self-adaption system. This review highlighted the bidirectional regulation of ROS in cancer. The study further discussed the application of massively accumulated ROS in cancer treatment. Of note, the dual role of ROS in cancer and the self-adaptive ability of cancer cells should be taken into consideration for cancer prevention.

Ionizing radiation induces epithelial-mesenchymal transition in human bronchial epithelial cells

Objective: The present study aimed to analyze the mechanism by which long-term occupational exposure of workers to low-dose ionizing irradiation induces epithelial–mesenchymal transition (EMT) of the human bronchial epithelial cells using transcriptome profiling.

Methods: RNA-seq transcriptomics was used to determine gene expression in blood samples from radiation-exposed workers followed by bioinformatics analysis. Normal bronchial epithelial cells (16HBE) were irradiated for different durations and subjected to immunofluorescence, Western blotting, scratch healing, and adhesion assays to detect the progression of EMT and its underlying molecular mechanisms.

Results: Transcriptomics revealed that exposure to ionizing radiation led to changes in the expression of genes related to EMT, immune response, and migration. At increased cumulative doses, ionizing radiation-induced significant EMT, as evidenced by a gradual decrease in the expression of E-cadherin, increased vimentin, elevated migration ability, and decreased adhesion capability of 16HBE cells. The expression of fibronectin 1 (FN1) showed a gradual increase with the progression of EMT, and may be involved in EMT.

Conclusion: Ionizing radiation induces EMT. FN1 may be involved in the progression of EMT and could serve as a potential biomarker for this process.

Long-term exposure to fine particle elemental components and lung cancer incidence in the ELAPSE pooled cohort

BACKGROUND

An association between long-term exposure to fine particulate matter (PM_2.5) and lung cancer has been established in previous studies. PM_2.5 is a complex mixture of chemical components from various sources and little is known about whether certain components contribute specifically to the associated lung cancer risk. The present study builds on recent findings from the "Effects of Low-level Air Pollution: A Study in Europe" (ELAPSE) collaboration and addresses the potential association between specific elemental components of PM_2.5 and lung cancer incidence.

METHODS

We pooled seven cohorts from across Europe and assigned exposure estimates for eight components of PM_2.5 representing non-tail pipe emissions (copper (Cu), iron (Fe), and zinc (Zn)), long-range transport (sulfur (S)), oil burning/industry emissions (nickel (Ni), vanadium (V)), crustal material (silicon (Si)), and biomass burning (potassium (K)) to cohort participants' baseline residential address based on 100 m by 100 m grids from newly developed hybrid models combining air pollution monitoring, land use data, satellite observations, and dispersion model estimates. We applied stratified Cox proportional hazards models, adjusting for potential confounders (age, sex, calendar year, marital status, smoking, body mass index, employment status, and neighborhood-level socio-economic status).

RESULTS

The pooled study population comprised 306,550 individuals with 3916 incident lung cancer events during 5,541,672 person-years of follow-up. We observed a positive association between exposure to all eight components and lung cancer incidence, with adjusted HRs of 1.10 (95% CI 1.05, 1.16) per 50 ng/m³ PM_2.5 K, 1.09 (95% CI 1.02, 1.15) per 1 ng/m³ PM_2.5 Ni, 1.22 (95% CI 1.11, 1.35) per 200 ng/m³ PM_2.5 S, and 1.07 (95% CI 1.02, 1.12) per 200 ng/m³ PM_2.5 V. Effect estimates were largely unaffected by adjustment for nitrogen dioxide (NO₂). After adjustment for PM_2.5 mass, effect estimates of K, Ni, S, and V were slightly attenuated, whereas effect estimates of Cu, Si, Fe, and Zn became null or negative.

CONCLUSIONS

Our results point towards an increased risk of lung cancer in connection with sources of combustion particles from oil and biomass burning and secondary inorganic aerosols rather than non-exhaust traffic emissions. Specific limit values or guidelines targeting these specific PM_2.5 components may prove helpful in future lung cancer prevention strategies.

Prediction of Particle-Collection Efficiency for Vacuum-Blowing Cleaning System Based on Operational Conditions

The dust-collection system, as the core of a sweeper vehicle, directly inhales dust particles on the pavement. The influence of variable operational conditions on particle-separation performance was investigated using computational fluid dynamics (CFD) Euler–Lagrange multiphase model. The particle-separation performance efficiency and retention time were used to evaluate the dust-collection efficiency. The uniform design (UD) and multiple regression analysis (MRA) methods were employed to predict and optimize the effects of reverse-blowing flow rate, pressure drop, and traveling speed on separation efficiency. The results indicated that the dust-collection performance initially increased and then decreased with increasing reverse-blowing flow rate. As the pressure drop increased, there was an increase in total dust-collection efficiency. However, the efficiency decreased with increasing traveling speed. The regression model showed that the proposed approach was able to predict the particle collection efficiency accurately. In addition, the optimum operational conditions were obtained, namely a reverse-blowing flow rate of 2100 m3/h, a traveling speed of 5 km/h, and a pressure drop of 2400 Pa. The maximum particle-separation efficiency was 99.10%, which showed good agreement with the experimental results.

Enhanced antitumor efficacy using epirubicin and schisandrin B co-delivery liposomes modified with PFV via inhibiting tumor metastasis

As a malignant tumor, breast cancer is very prone to metastasis. Chemotherapy is one of the most common means for treating breast cancer. However, due to the serious metastasis and the poor targeting effect of traditional chemotherapeutic drugs, even after years of efforts, the therapeutic effect is still unsatisfied. Therefore, in this study, we constructed a kind of PFV modified epirubicin plus schisandrin B liposomes to solve the above disadvantages. In vitro experiments showed that the targeting liposomes with ideal physicochemical property could increase the cytotoxicity of MDA-MB-435S cells, destroy the formation of vasculogenic mimicry (VM), and inhibit tumor invasion and migration. Action mechanisms indicated that the inhibition of targeting liposomes on tumor metastasis was attributed to the regulation of the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), vimentin (VIM), and E-cadherin (E-cad). In vivo pharmacodynamic experiments showed that the targeting liposomes could significantly improve the antitumor effect in mice. H&E staining and TUNEL results showed that the targeting liposomes could promote the apoptosis of tumor cells. Hence, the PFV modified epirubicin plus schisandrin B liposomes constructed in this study provided a new therapeutic strategy for breast cancer.

Oxygenated Polycyclic aromatic hydrocarbons (Oxy-PAHs) facilitate lung cancer metastasis by epigenetically regulating the epithelial-to-mesenchymal transition (EMT)

Oxygenated Polycyclic aromatic hydrocarbons (Oxy-PAHs) are widely distributed in the atmosphere, water, soil and sediments. Oxy-PAHs have been proved more carcinogenic than their parent PAHs, while there still lack of studies about the toxicological mechanism of Oxy-PAHs in epigenetic regulation. Our study revealed that exposure to Oxy-PAHs induced the invasion and migration of lung epithelial cells by the activation of epithelial-to-mesenchymal transition (EMT), including the up-regulation of Vimentin and alpha-smooth muscle actin (α-SMA) and the down-regulation of E-cadherin (E-cad). The reactive oxygen species (ROS) promoted histone acetylation mediated-Snail regulating the expression of E-cad after Oxy-PAHs treatment. Meanwhile, DNA methylation was also involved in epigenetic regulation of EMT. These results demonstrated a potential mechanism about Oxy-PAHs facilitate lung carcinogenesis by epigenetic regulation and suggested new ways for the treatment, improvement, and prevention of lung cancer caused by Oxy-PAHs environmental exposure.

PM2.5-associated nitro-PAH exposure promotes tumor cell metastasis through Hippo-YAP mediated transcriptional regulation

Extensive epidemiological studies have revealed that nearly 25% of the premature mortality from lung cancer is attributed to regional haze caused by a high level of fine particulate matter (PM_2.5). The nitro-PAHs (NPAHs), with a lower volatility, are more likely to be absorbed with PM_2.5 and to pose a threat to health, whereas there is insufficient information about carcinogenesis caused by NPAHs. Our study evaluated the carcinogenic effect of typical NPAHs on lung cancer cell adhesion and metastasis and revealed the possibly involved mechanism through in vitro experiments. For the specific mechanism, typical NPAHs could directly induce the inactivation of serine/threonine kinase (MST1/2) and large tumor suppressor (LATS1/2) and result in the nuclear translocation of Yes-associated protein (YAP). The nuclear YAP would then combine with TEA domain transcription factor (TEAD) and profoundly influence the transcription of migration and adhesion genes related to lung cancer metastasis. These findings remind us of the possible carcinogenicity of NPAHs absorbed with PM_2.5 and provide a reference for the prevention and mitigation of tumorigenesis in a heavily polluted environment.

Complex to simple: In vitro exposure of particulate matter simulated at the air-liquid interface discloses the health impacts of major air pollutants

Particulate matter (PM) exposure poses many adverse effects on human health. However, it is challenging to clearly differentiate between the contributions of individual pollutants on toxicity from complex mixtures of ambient air pollutants. The aim of this study is to generate aerosols constituted by silica nanoparticles (NPs) and bisulfate to serve as simulators of particle-associated high-sulfur air pollution. Then, the health impacts of sulfur dioxide were evaluated at the cellular level using an air-liquid interface (ALI) exposure chamber. BEAS-2B cells were exposed to either nano-silica or bisulfite aerosol individually or bisulfate-coated silica (SiO₂-NH₂@HSO₃) for 3 h using the ALI. The cellular toxicities were carefully compared based on the exposure dosages. The ALI exposure of SiO₂ NPs alone did not produce any apparent cytotoxicity in cells, but the aerosol exposure of SiO₂-NH₂@HSO₃ significantly decreased the cell viability and enhanced the production of cellular reactive oxygen species in a dose-dependent manner. Consequently, the excessive oxidative stress resulted in mitochondrial damage as well as cellular apoptosis. ALI exposure can possibly reflect the realistic physiological exposure condition of the human respiratory system. As a derivative of the sulfur dioxide component of air pollution, sulfate exacerbates the toxic effects of inhalable PMs. This result may be due to the large surface area of the nanoparticles, with the possibility of carrying more sulfite to the target cells during aerosol exposure. The sulfate levels offer a meaningful complement to the present PM_2.5 index of air pollution for achieving better human health protection.

Ang-2 promotes lung cancer metastasis by increasing epithelial-mesenchymal transition

Lung cancer is the most common malignant tumor with increasing angiopoietin-2 (Ang-2) and a high rate of metastasis. However, the mechanism of Ang-2 enhancing tumor proliferation and facilitating metastasis remains to be clarified. In this study, Ang-2 expression and its gene transcription on effects of biological behaviors and epithelial-mesenchymal transition (EMT) were investigated in lung cancers. Total incidence of Ang-2 expression in the cancerous tissues was up to 91.8 % (112 of 122) with significantly higher (χ²=103.753, P²=7.883, P=0.005), differentiation degree (χ²=4.554, P=0.033), tumor node metastasis (TNM) staging (χ²=5.039, P=0.025), and 5-year survival rate (χ² =11.220, P²=18.881, P²=0.81, P=0.776) or III & IV (χ²=1.845, P=0.174). Over-expression of Ang-2 or Ang-2 mRNA in lung A549 and NCI-H1975 cells were identified among different cell lines. When silencing Ang-2 in A549 cells with specific shRNA-1 transfection, the cell proliferation was significantly inhibited in a time-dependent manner, with up-regulating E-cadherin, down-regulating Vimentin, Twist, and Snail expression, and decreasing invasion and metastasis of cancer cell abilities, suggesting that Ang-2 promote tumor metastasis through increasing EMT, and it could be a potential target for lung cancer therapy.