Characterization of solid tumors induced by polycyclic aromatic hydrocarbons in mice

Global occurrence, food web transfer, and human health risks of polycyclic aromatic hydrocarbons in biota

Polycyclic aromatic hydrocarbons (PAHs) are widespread organic pollutants that pose significant health risks due to their bioaccumulation in the biota. This study examines the global distribution of PAHs in biota, identifies key factors influencing using boosted regression tree (BRT) models, analyzes their transfer through trophic magnification factors (TMF), and evaluates health risks using the EPA risk assessment model. Research on PAHs has grown from 1978 to 2023, peaking in 2021, with 171 out of 241 studies (71.1 %) focusing on marine ecosystems. The highest PAH concentrations are observed in the Mediterranean Sea, Red Sea, and North American coastal regions, primarily influenced by industrial and human activities, such as factory emissions and ship transport. BRT analysis shows region factors and feeding habitats significantly influence PAH levels. TMF analysis shows that biodilution is the main mechanism for PAH attenuation, with concentrations decreasing as trophic levels increase. Additionally, health risk assessment further illustrate that toxicity equivalent (TEQ) values are highest in Egypt and Turkey. Across all populations in Egypt, the United States, Turkey, Portugal, and China, as well as children in Portugal and Sweden, there are potential risks from aquatic product consumption (10-6 < CRI < 10-4), with CRI values positively correlated with liver cancer incidence. While hazard quotients (HQ) < 1 suggest overall safety, higher obesity risks are noted, particularly among women and adolescents.

Dynamic changes of DNA methylation induced by benzo(a)pyrene in cancer

Benzo(a)pyrene (BaP), the earliest and most significant carcinogen among polycyclic aromatic hydrocarbons (PAHs), has been found in foods, tobacco smoke, and automobiles exhaust, etc. Exposure to BaP induced DNA damage directly, or oxidative stress-related damage, resulting in cell apoptosis and carcinogenesis in human respiratory system, digestive system, reproductive system, etc. Moreover, BaP triggered genome-wide epigenetic alterations by methylation, which might cause disturbances in regulation of gene expression, and thereby induced cancer. It has been proved that BaP reduced genome-wide DNA methylation, and activated proto-oncogene by hypomethylation in the promoter region, but silenced tumor suppressor genes by promoter hypermethylation, resulting in cancer initiation and progression. Here we summarized the changes in DNA methylation in BaP exposure, and revealed the methylation of DNA plays a role in cancer development.

In Silico Approach in the Evaluation of Pro-Inflammatory Potential of Polycyclic Aromatic Hydrocarbons and Volatile Organic Compounds through Binding Affinity to the Human Toll-Like Receptor 4

Polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) are widespread across the globe, existing in the environment in complex mixtures potentially capable of initiating respiratory illnesses. Here, we use an in silico approach to evaluate the potential pro-inflammatory effects of various carcinogenic PAHs and VOCs through their binding affinity towards the human toll-like receptor 4 (TLR4). For receptors and ligands, RCSB Protein Data Bank and PubChem were used in obtaining their 3D structures, respectively. Autodock Vina was utilized to obtain the best docking poses and binding affinities of each PAH and VOC. Out of the 14 PAHs included in this study, indeno(1,2,3-cd)pyrene, benzo(ghi)perylene, and benzo[a]pyrene had the highest binding affinity values of −10, −9, and −8.9 kcal/mol, respectively. For the VOCs, out of the 10 compounds studied, benzene, 1,4-dichlorobenzene, and styrene had the highest binding affinity values of −3.6, −3.9, and −4.6 kcal/mol, respectively. Compounds with higher affinity than LPS (−4.1 kcal/com) could potentially induce inflammation, while compounds with lower affinity would be less likely to induce an inflammatory response. Meanwhile, molecular dynamics simulation and RMSF statistical analysis proved that the protein, TLR4, stably preserve its conformation despite ligand interactions. Overall, the structure of the TLR4 was considered inflexible.

Long-term environmental surveillance of PM2.5-bound polycyclic aromatic hydrocarbons in Jinan, China (2014-2020): Health risk assessment

We established long-term surveillance sites in Jinan city to monitor PM_2.5 particles (PM2.5) and PM2.5-bound PAHs (2014-2020). The range of PM2.5 was 15-230 µg/m³. The average annual ƩPAH₁₆ were 433 ± 271 ng/m³ (industrial area) and 299 ± 171.8 ng/m³ (downtown). PAHs captured in winter accounted for 61.5% (industrial area) and 59.1% (downtown) of total PAHs. A hazardous seasonal benzo[a]pyrene level was detected in 2015-2016 winter as 14.03 ng/m³ (14 folds of EU standard). The dominant PM2.5-bound PAHs were benzo[b]fluoranthene (24-26%), chrysene (19-20%), benzo[g,h,i]perylene (15%), Indeno(1,2,3-cd)pyrene (12%) and Benzo[a]pyrene (10%). Toxic equivalent quotients of PAHs were 4.93 ng/m³ (industrial area) and 3.13 ng/m³ (downtown). Excess cancer risks (ECRs) were 4.3 × 10^-4 ng/m³ and 2.7 × 10^-4 ng/m³, respectively. The ECRs exceeded EPA regulatory limit of 1 × 10^-6 ng/m³ largely. Non-negligible excess lifetime cancer risks were found as 36 and 26 related cancer incidences per 1,000,000 people. Consistently, local prevalence of lung cancer raise from 56.97/100,000 to 72.38/100,000; the prevalence of thyroid cancer raise from 10.12/100,000 to 45.26/100,000 from 2014 to 2020. Our findings suggest an urgent need to investigate the adverse health effects of PAHs on local population and we call for more strictly restriction on coal consumption and traffic tail gas emission.

Cancer in Iran 2008 to 2025: Recent incidence trends and short-term predictions of the future burden

Policymakers require estimates of the future number of cancer patients in order to allocate finite resources to cancer prevention, treatment and palliative care. We examine recent cancer incidence trends in Iran and present predicted incidence rates and new cases for the entire country for the year 2025. We developed a method for approximating population-based incidence from the pathology-based data series available nationally for the years 2008 to 2013, and augmented this with data from the Iranian National Population-based Cancer Registry (INPCR) for the years 2014 to 2016. We fitted time-linear age-period models to the recent incidence trends to quantify the future cancer incidence burden to the year 2025, delineating the contribution of changes due to risk and those due to demographic change. The number of new cancer cases is predicted to increase in Iran from 112 000 recorded cases in 2016 to an estimated 160 000 in 2025, a 42.6% increase, of which 13.9% and 28.7% were attributed to changes in risk and population structure, respectively. In terms of specific cancers, the greatest increases in cases are predicted for thyroid (113.8%), prostate (66.7%), female breast (63.0%) and colorectal cancer (54.1%). Breast, colorectal and stomach cancers were the most common cancers in Iran in 2016 and are predicted to remain the leading cancers nationally in 2025. The increasing trends in incidence of most common cancers in Iran reinforce the need for the tailored design and implementation of effective national cancer control programs across the country.

The role of gut microbial community and metabolomic shifts in adaptive resistance of Atlantic killifish (Fundulus heteroclitus) to polycyclic aromatic hydrocarbons

Altered gut microbiomes may play a role in rapid evolution to anthropogenic change but remain poorly understood. Atlantic killifish (Fundulus heteroclitus) in the Elizabeth River, VA have evolved resistance to polycyclic aromatic hydrocarbons (PAHs) and provide a unique opportunity to examine the links between shifts in the commensal microbiome and organismal physiology associated with evolved resistance. Here, 16S rRNA sequence libraries derived from fish guts and sediments sampled from a highly PAH contaminated site revealed significant differences collected at similar samples from an uncontaminated site. Phylogenetic groups enriched in the libraries derived from PAH-resistant fish were dissimilar to their associated sediment libraries, suggesting the specific environment within the PAH-resistant fish intestine influence the gut microbiome composition. Gut metabolite analysis revealed shifts between PAH-resistant and non-resistant subpopulations. Notably, PAH-resistant fish exhibited reduced levels of tryptophan and increased levels of sphingolipids. Exposure to PAHs appears to impact several bacterial in the gut microbiome, particularly sphingolipid containing bacteria. Bacterial phylotypes known to include species containing sphingolipids were generally lower in the intestines of fish subpopulations exposed to high concentrations of PAHs, inferring a complex host-microbiome relationship. Overall, killifish microbial community shifts appear to be related to a suppression of overall metabolite level, indicating a potential role of the gut in organismal response to anthropogenic environmental change. These results on microbial and metabolomics shifts are potentially linked to altered bioenergetic phenotype observed in the same PAH-resistant killifish populations in other studies.

Chemopreventive effect of galangin against benzo(a)pyrene-induced stomach tumorigenesis through modulating aryl hydrocarbon receptor in Swiss albino mice

The present study was aimed to evaluate the chemopreventive potential of galangin against benzo(a)pyrene (BaP)-induced stomach carcinogenesis in Swiss albino mice. Stomach cancer was induced in experimental mice using BaP oral administration. The mice were treated with galangin (10 mg/kg b.wt.) before and during BaP administration. Oral administration of galangin at a dose of 10 mg/kg b.wt. significantly (p < 0.05) prevented the tumor incidence, tumor volume in the experimental animals. Further, galangin pretreatment prevents BaP-induced lipid peroxidation and restores BaP-mediated loss of cellular antioxidants status. It has also been found that galangin prevents BaP-induced activation of phase I detoxification enzymes. Furthermore, galangin pretreatment prevented the BaP-induced overexpression of cytochrome P450s isoform genes (CYP1A1, CYP1B1), aryl hydrocarbon receptor system (AhR, ARNT), transcriptional activators (CBP/p300, NF-kB), tumor growth factors, proto-oncogenes, invasion markers (TGFB, SRC-1, MYC, iNOS, MMP2, MMP9) and Phase II metabolic isoenzyme genes (GST) in the stomach tissue homogenate when compared to the control groups. The western blot results confirm that galangin (10 mg/kg. b.wt.) treatment significantly prevented the BaP-mediated expression of ArR, ARNT, and CYP1A1 proteins in the mouse stomach tissue. Therefore, the present results confirm that galangin prevents BaP-induced stomach carcinogenesis probably through modulating ArR and ARNT expression in the experimental mice.

Public health issues from crude-oil production in the Ecuadorian Amazon territories

Crude oil production (COP) is a high-pollution industry but the vast Amazon rainforest has been an active COP zone for South America. Although COP has been associated with a variety of health effects among workers around the world, such effects have not been adequately investigated in the Amazon region, especially at the community level. Therefore, this review was conducted to provide a report about COP in the Amazon of Ecuador and about its association with health status of indigenous human populations. Some epidemiological surveys in the Amazonian Territories indicate that COP has been associated with health problems in the surrounding populations, e.g. cancers in the stomach, rectum, skin, soft tissue, kidney and cervix in adults, and leukemia in children. In addition, some biomarkers and mechanistic studies show exposure effects. However, due to limitations from these studies, contradictory associations have been reported. Our review indicates that COP in the Amazonian territories of northern Ecuador was characterised by contamination which could have affected the indigenous and non-indigenous populations. However, there have not been dedicated investigations to provide relationships between the contamination and the subsequent exposure-health effects. Since indigenous populations have different lifestyle and cultures from regular city dwellers, systematic studies on their potential health hazards need to be conducted. Due to the remote locations and sparse populations, these new studies may involve the use of novel and genomic-based biomarkers as well as using high technology in the remote regions.

Inhibition of Bcl6b promotes gastric cancer by amplifying inflammation in mice

Background

Chronic gastritis has been demonstrated to be a key cause of gastric cancer (GC), and control of gastric inflammation is regarded as an effective treatment for the clinical prevention of gastric carcinogenesis. However, there remains an unmet need to identify the dominant regulators of gastric oncogenesis-associated inflammation in vivo.

Methods

The mouse model for the study of inflammation-associated GC was induced by Benzo[a]pyrene (BaP) intragastric administration in Bcl6b^−/− and wildtype mice on a C57BL/6 background. 5-Aza-2′-deoxycytidine (5-Aza), the demethylation drug, was intraperitoneally injected to restore Bcl6b expression. Human GC tissue array was used to analyse patient survival based on BCL6B and CD3 protein expression.

Results

Bcl6b was gradually downregulated by its own promoter hypermethylation in parallel to an increasing inflammatory response during the progression of BaP-induced gastric carcinogenesis in mice. Moreover, knockout of Bcl6b dramatically worsened the severity of gastric cancer and aggravated the inflammatory response in the BaP-induced mice GC model. Re-activation of Bcl6b by 5-Aza impeded inflammatory amplification and BaP-induced GC development, prolonging survival time in wildtype mice, whereas no notable curative effect occurred in Bcl6b^−/− mice with 5-Aza treatment. Finally, significant negative correlations were detected between the mRNA levels of BCL6B and inflammatory cytokines in human GC tissues; patients harbouring BCL6B-negetive and severe-inflammation GC tumours were found to exhibit the shortest survival time.

Conclusions

Epigenetic inactivation of Bcl6b promotes gastric cancer through amplification of the gastric inflammatory response in vivo and offers a new approach for GC treatment and regenerative medicine.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0387-6) contains supplementary material, which is available to authorized users.

MicroRNA-495 Inhibits Gastric Cancer Cell Migration and Invasion Possibly via Targeting High Mobility Group AT-Hook 2 (HMGA2)

Background

Gastric cancer is one of the most common malignancies, and has a high mortality rate. miR-495 acts as a suppressor in some cancers and HMGA2 (high mobility group AT-hook 2) is a facilitator for cell growth and epithelial-mesenchymal transition (EMT), but little is known about their effect in gastric cancer. This study aimed to investigate the role and mechanism of miR-495 in gastric cancer.

Material/Methods

miR-495 levels were quantitatively analyzed in gastric cancer tissue and GES-1, SGC-7901, BGC-823, and HGC-27 cell lines by qRT-PCR. Levels of miR-495 and HMGA2 were altered by cell transfection, after which cell migration and invasion were examined by Transwell and E-cadherin (CDH1); vimentin (VIM), and alpha smooth muscle actin (ACTA2) were detected by qRT-PCR and Western blotting. The interaction between miR-495 and HMGA2 was verified by dual-luciferase reporter assay.

Results

miR-495 was significantly downregulated in cancer tissue and cell lines (p<0.05). Its overexpression inhibited cell migration and invasion, elevated CDH1, and inhibited VIM and ACTA2 levels in BGC-823 and HGC-27 cells. miR-495 directly inhibited HMGA2, which was upregulated in gastric cancer tissue, and promoted cell migration and invasion, inhibited CDH1, and elevated VIM and ACTA2.

Conclusions

miR-495 acts as a tumor suppressor in gastric cancer by inhibiting cell migration and invasion, which may be associated with its direct inhibition on HMGA2. These results suggest a promising therapeutic strategy for gastric cancer treatment.

Environmental carcinogenesis and pH homeostasis: Not only a matter of dysregulated metabolism

According to the World Health Organization, around 20% of all cancers would be due to environmental factors. Among these factors, several chemicals are indeed well recognized carcinogens. The widespread contaminant benzo[a]pyrene (B[a]P), an often used model carcinogen of the polycyclic aromatic hydrocarbons' family, has been suggested to target most, if not all, cancer hallmarks described by Hanahan and Weinberg. It is classified as a group I carcinogen by the International Agency for Research on Cancer; however, the precise intracellular mechanisms underlying its carcinogenic properties remain yet to be thoroughly defined. Recently, the pH homeostasis, a well known regulator of carcinogenic processes, was suggested to be a key actor in both cell death and Warburg-like metabolic reprogramming induced upon B[a]P exposure. The present review will highlight those data with the aim of favoring research on the role of H⁺ dynamics in environmental carcinogenesis.

Expression of IL-1α and IL-6 is Associated with Progression and Prognosis of Human Cervical Cancer

Background

IL-1α and IL-6 are associated with the prognosis of a wide range of cancers, but their value in cervical cancer remains controversial. The aim of this study was to investigate the expression of IL-1α and IL-6 in cervical cancer and their significance in clinical prognosis.

Material/Methods

The expression of IL-1α and IL-6 in 105 formalin-fixed, paraffin-embedded cervical cancer tissues and adjacent non-tumor tissues was examined by immunohistochemistry. The results were semi-quantitatively scored and analyzed by chi-square test. Patient overall survival (OS) data was collected by follow-up and analyzed by Kaplan-Meier analysis.

Results

The expression level of both IL-1α and IL-6 in cervical cancer tissue was higher than in adjacent non-tumor tissues (p<0.05). IL-1α expression was shown to be correlated with tumor size, FIGO histology grade, lymph node metastasis, stromal invasion, and tumor differentiation (p<0.05). IL-6 expression was shown to be correlated with tumor size, FIGO histology grade, and tumor differentiation (p<0.05). Patients with positive expression of IL-1α or IL-6 tended to have much shorter survival times than patients with negative expression. In addition, a multivariate Cox regression analysis demonstrated that IL-1α expression and lymph node metastasis were independent predictors of OS in cervical cancer patients.

Conclusions

The expression of IL-1α was significantly associated with tumor size, FIGO histology grade, lymph node metastasis, stromal invasion, and tumor differentiation. The expression of IL-6 was significantly associated with tumor size, FIGO histology grade, and tumor differentiation. Positive IL-1α and IL-6 expression was significantly correlated with poor prognosis. They may be considered valuable biomarkers for prognosis and potential therapeutic targets for cervical cancer.

B7-H4 is Predictive of Poor Prognosis in Patients with Gastric Cancer

Background

Recently, some studies were performed to evaluate the relevance of B7-H4 and gastric cancer (GC) prognosis. However, the results remained controversial. Therefore, we performed the present meta-analysis.

Material/Methods

We performed a systematic search in PubMed and Web of Science databases. All data were extracted and reviewed from each eligible study independently by 2 investigators. The strength of association between B7-H4 and GC prognosis was assessed by computing odds ratio (OR) with its corresponding 95% confidence interval (CI).

Results

Six studies that evaluated the association between B7-H4 and GC prognosis were included. The results showed a statistically significant association of B7-H4 and GC prognosis (OR=1.63, 95%CI=1.30–2.03). Furthermore, we conducted subgroup analysis based on source of B7-H4; the results from blood (OR=1.71; 95%CI, 1.09–2.68) and tissue (OR=1.60; 95%CI, 1.03–2.07) indicated B7-H4 was significantly associated with poor prognosis.

Conclusions

This meta-analysis suggests that GC patients with high B7-H4 have poor prognosis.

Effect of Splenectomy Combined with Resection for Gastric Carcinoma on Patient Prognosis

BACKGROUND For patients with stage IV gastric cancer, it is unclear whether splenectomy combined with palliative surgery is needed to reduce tumor load and relieve symptoms. The objective of the present study was to investigate the effect of splenectomy combined with palliative resection for stage IV gastric carcinoma on immunological dysfunction and patient prognosis. MATERIAL AND METHODS We retrospectively analyzed medical records of 106 stage IV gastric cancer patients who underwent palliative surgery; of these, 49 patients were treated with palliative resection for gastric carcinoma combined with splenectomy, while the other 57 patients retained their spleens. The immunologic function and prognosis in these 2 groups were examined and compared. RESULTS The immune function of patients in the group that retained their spleens was better later in the postoperative course than in the resection group. The groups did not show statistically significant differences in postoperative infectious complications, median survival time, and survival rate; however, the average postoperative hospitalization time of patients in the retained group was significantly shorter. CONCLUSIONS Splenectomy combined with gastric cancer resection did not improve the prognosis of the patients; patients who retained their spleens had faster recovery and improved immune function. However, whether retaining the spleen is an independent factor improving the prognosis needs further investigation.

Benzo[a]pyrene promotes gastric cancer cell proliferation and metastasis likely through the Aryl hydrocarbon receptor and ERK-dependent induction of MMP9 and c-myc

Gastric cancer (GC) is the fifth most common cancer worldwide and the third leading cause of global cancer-related death. Benzo[a]pyrene (BaP), a Group Ⅰ carcinogen categorized by the IARC, is a cumulative foodborne carcinogen and ubiquitous environmental pollutant with potent carcinogenic properties. However, the function and mechanism of BaP exposure on GC progression remains unclear. We investigated the role of BaP in human GC progression to identify potential mechanism underlining its carcinogenic activity. After exposure to various concentrations of BaP, human GC cells SGC-7901 and MNK-45 showed an increased capability of proliferation, migration and invasion. Further study indicated that BaP promotes the expression of matrix metalloproteinase-9 (MMP9) and c-myc at mRNA and protein level, and activates Aryl hydrocarbon receptor (AhR) and ERK pathway. Moreover, BaP-induced overexpression of MMP9 and c-myc were attenuated by the ERK inhibitor U0126 and AhR inhibitor resveratrol, respectively. These data suggest that BaP promotes proliferation and metastasis of GC cells through upregulation of MMP9 and c-myc expression, and this was likely mediated via the AhR and ERK signaling pathway.

Effect of Over-Expression of Zinc-Finger Protein (ZFX) on Self-Renewal and Drug-Resistance of Hepatocellular Carcinoma

Background

X-chromosome-coupled zinc finger protein (ZFX) in the Zfy protein family is abundantly expressed in both embryonic and hematopoietic stem cells (HSCs). ZFX exist in various tumor cells and is correlated with proliferation and survival of tumor cells. As a malignant tumor with high invasiveness, hepatocellular carcinoma (HCC) may present resistance against chemotherapy and features of stem cells. This study aimed to explore the expression of ZFX in HCC cells, in an attempt to illustrate the role of ZFX in tumorigenesis.

Material/Methods

The expression of ZFX in tumor tissues was quantified by RT-PCR. The ZFX expression was then silenced to evaluate the stem cell-like features of HCC cells, including self-renewal, colony formation, and cell cycle, along with the sensitivity to cisplatin. Xenograft of ZFX-overexpressed HCC on nude mice was performed to evaluate the in vivo effect of ZFX on tumor growth.

Results

Quantitative RT-PCR showed over-expression of ZFX in 51.8% of HCC tumors. The silencing of ZFX gene inhibited the self-renewal, colony formation, and proliferation ability of HCC cells (p<0.05 in all cases) via the cell cycle arrest at G0/G1 phase, in addition to the elevated sensitivity of tumor cells to cisplatin (p<0.001). Further studies showed that binding between ZFX and promoter regions of Nanog or SOX-2 regulatory factor initiate their expression in HCC cells. The xenograft experiment indicated the potentiation of tumor growth by ZFX over-expression.

Conclusions

ZFX is over-expressed in HCC cells, and correlates with stem cell-like features and pleiotropic characteristics.

Expression of Mismatch Repair Proteins in Early and Advanced Gastric Cancer in Poland

BACKGROUND Mutations in DNA of mismatch repair (MMR) genes result in failure to repair errors that occur during DNA replication in microsatellites, resulting in accumulation of frameshift mutations in these genes and leading to DNA mismatch replication errors and microsatellite instability. Gastric cancers (GCs) with high MSI (MSI-H) are a well-defined subset of carcinomas showing distinctive clinicopathological features. In this study we investigated the rate of MSI and the correlation between MSI status and clinicopathological features of GC. MATERIAL AND METHODS The study included 107 patients with GCs: 61 with advanced gastric cancers (AGC) and 46 with early gastric cancer (EGC). MSI deficiency in GCs was assessed by the immunohistochemical analysis of expression of MMR proteins - MLH1, MSH2, MSH6, and PMS2 - using formalin-fixed and paraffin-embedded tissue. RESULTS A total of 6 (5.6%) MSI-H were observed. The loss of MMR proteins expression was associated with the intestinal type of GC in Lauren classification, and tubular and papillary architecture in WHO classification. There was no statistically significant association between negative MMR expression and other selected clinical parameters: age, sex, tumor location, depth of invasion (EGC and AGC), lymph nodes status, presence of the ulceration, and lymphocytic infiltrate. CONCLUSIONS In the present era of personalized medicine, the histological type of GC and MMR proteins status in cancer cells are very important for the proper surveillance of patients with familial GC and sporadic GCs, as well as for selecting the proper follow-up and treatment. Larger collaborative studies are needed to verify the features of MSI-H GCs in Poland.

Assessment of Reliability when Using Diagnostic Binary Ratios of Polycyclic Aromatic Hydrocarbons in Ambient Air PM10

The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand. The major objectives of this research were to evaluate the effects of day and night on the alterations of six different PAH diagnostic binary ratios: An/(An + Phe), Fluo/(Fluo + Pyr), B[a]A/(B[a]A + Chry), B[a]P/(B[a]P + B[e]P), Ind/(Ind + B[g,h,i]P), and B[k]F/Ind, and to investigate the impacts of site-specific conditions on the alterations of PAH diagnostic binary ratios by applying the concept of the coefficient of divergence (COD). No significant differences between day and night were found for any of the diagnostic binary ratios of PAHs, which indicates that the photodecomposition process is of minor importance in terms of PAH reduction. Interestingly, comparatively high values of COD for An/(An + Phe) in PM10 collected from sites with heavy traffic and in residential zones underline the influence of heterogeneous reactions triggered by oxidising gaseous species from vehicular exhausts. Therefore, special attention must be paid when interpreting the data of these diagnostic binary ratios, particularly for cases of low-molecular-weight PAHs.

Tumor Suppressor Role of miR-363-3p in Gastric Cancer

Background

Gastric cancer (GC) is the most common cancer in the world. Despite the advancement of the treatment of GC, the 5-year overall survival rate is still very low. MicroRNAs (miRNAs) play important roles in the pathogenesis of GC. A recent study suggested that miR-363-3p plays a role in the development of GC. However, the function of miR-363-3p in GC is not fully understood.

Material/Methods

The network of NOTCH1 and the involved molecules was constructed by use of Cytoscape software. MiR-363-3p levels in GC tissues and cells were tested by qRT-PCR. Cells were miR-363-3p mimics or anti-miR-363-3p transfected by Lipofectamine. Bioinformatics algorithms from TargetScanHuman were used to predict the target genes of miR-363-3p. The NOTCH1 protein level was tested by Western blot. The interaction between miR-363-3p and NOTCH1 was confirmed by dual luciferase assays.

Results

MiR-363-3p showed low levels in GC tissues and cells. Enforced expression of miR-363-3p inhibited cell growth and migration of GC cells and vice versa. NOTCH1 is the targeted gene of miR-363-3p.

Conclusions

MiR-363-3p plays a tumor suppressor role in GC.