[Determination of 14 aniline and benzidine compounds in soil by gas chromatography-mass spectrometry]

The complex matrix of soil samples and low extraction efficiency of aniline compounds limit many methods developed for detecting aniline and benzidine compounds in soil. In this study, a rapid and sensitive method based on gas chromatography-mass spectrometry was developed for the simultaneous determination of 14 aniline and benzidine compounds in soil. The collected soil samples were sealed with 5% sodium sulfite solution and refrigerated to inhibit the oxidation of the target compounds for up to 7 d. The extraction efficiencies of accelerated solvent extraction and oscillating dispersion extraction were compared, and the recovery of accelerated solvent extraction was found to be unsuitable. Hence, three-phase oscillating dispersion extraction was adopted. A certain amount of alkaline aqueous solution was added to the test system during extraction to improve the extraction efficiency because aniline and benzidine compounds are weakly alkaline substances. When the pH of the extracted water phase was greater than 12, relatively good recoveries were obtained. Next, a mixed solvent of ethyl acetate-methylene chloride (1∶4, v/v) was added to extract the target compounds via oscillation for 20 min. The solid phase was discarded via centrifugation, and the aqueous and organic phases were transferred to a liquid separation funnel for further separation. Finally, the organic phase was retained. This pretreatment process prevents the co-extraction of acidic compounds or other impurities, thereby enhancing the purification ability of the method. Solid phase extraction (SPE) is generally recommended for soil extraction and purification. A preliminary test showed that compared with other columns, the Florisil SPE column could better retain the target substances and exhibited higher elution efficiency. After purification, the organic phase was concentrated to 1 mL using a nitrogen blower. The analytes were analyzed by gas chromatography-mass spectrometry using a capillary column (DB-35MS, 30 m×0.25 mm×0.25 μm). The temperature program was optimized to separate the target compounds at the baseline. Specifically, the initial oven temperature was set to 60 ℃, held for 2 min, increased to 130 ℃ at a rate of 5 ℃/min, increased to 300 ℃ at a rate of 30 ℃/min, and held for 4 min. The injector and ion source temperatures were 250 and 300 ℃, respectively. Aniline-d5 and acenaphthene-d10 were used as the internal standards for quantification. The effects of antioxidant addition, extraction solvent type, salting out, and other factors on extraction efficiency were investigated. The results showed that the method performed well under the optimized experimental conditions when actual soils were used as real sample matrices. The accuracy and precision of the proposed method were verified. A total of 14 aniline and benzidine compounds demonstrated good linearities in the range of 0.5-100 mg/L. The method detection limits (MDLs) ranged from 0.02 to 0.07 mg/kg, and the limits of quantification (LOQs) ranged from 0.08 to 0.28 mg/kg. The target compounds were spiked at contents of 1 and 10 mg/kg. The spiked recoveries of the 14 targets in actual soils were 62.9%-101%, and the relative standard deviations (RSDs) of six precision tests were 3.8%-10.3%. The proposed method effectively inhibited the oxidation of aniline and benzidine compounds during extraction, and the target compounds exhibited high recoveries and good stabilities in the presence of three phases. Moreover, the operating procedure was simple and easy to implement. The proposed method was applied to the soil collected from an industrial enterprise in Jiangsu province that was suspected to be contaminated with aniline, and two aniline compounds were detected. The developed method requires a small sample size, and the preservation step is simple and effective. In addition, it can be applied to various types of actual soils. The method meets the requirements of current soil pollution risk control standards for aniline and benzidine compounds in soils.

Abstract B114: Progesterone receptor membrane component 1 is a candidate key molecule involved EGFR-TKI resistance in lung adenocarcinoma

To overcome the resistance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) in non-small cell lung cancer, the mechanism clarification and novel molecular target development are urgently required. From this viewpoint, we previously identified by proteomics analysis progesterone receptor membrane component 1 (PGRMC1) as a new candidate target of EGFR-TKI resistance. However, the detailed mechanism of PGRMC1 in acquired resistance to EGFR-TKI is still obscure. In this study, we investigated the role and mechanism of PGRMC1 in EGFR-TKI resistance. First, to understand the significance of PGRMC1 in EGFR-TKI resistance, PC9/ER, which was constructed with increasing concentration erlotinib for 6 months and required resistance to erlotinib with PGRMC1 up-regulated, and its parental cell line PC9 were used. The wst-8 assay was executed after PGRMC1 inhibitor (AG-205) was treated to cells. The results showed that, compared to PC9 treated with AG-205, PC9/ER showed a significant reduction in viability with AG-205 treatment. Since AG-205 was reported to inhibit PGRMC1-heme complex formation and the ferrous from liberated heme could induce the ferroptosis, we detected the intracellular ferrous by ferroOrange when cells were treated with AG-205. Although PC9/ER showed lower ferrous than PC9, both cells showed induction of free ferrous when treated with AG-205. In the meantime, we measured the viability of two cells when treated by erastin and hemin, which are ferroptosis activators. Similar results to AG-205 were showed in PC9/ER with activators, which had lower viability than PC9 with activators. Since the side effect from high dosage treatment usually, not only the single treatment of AG-205, but low dosage co-treatment of AG-205 and erlotinib was also evaluated. Compared with PC9, which showed little variation in combination treatment, co-treatment in PC9/ER showed significant reductions in viability. Besides, immunofluorescence showed the ferrous decreased when erlotinib was treated and then increased when AG-205 was further added. These results showed that PGRMC1 might reduce ferroptosis and lead to erlotinib resistance. Collectively, these findings suggest important roles of ferroptosis reduction by PGRMC1 in erlotinib resistance. Since the single or co-treatment showed a significant efficiency, PGRMC1 might provide a new therapeutic target for lung adenocarcinoma.

Citation Format: Ying LIN, Kazuma HIGASHISAKA, Sachiyo HANAMURO, Kohei IZUSAWA, Hiroto KONISHI, Yuya HAGA, Lili YANG, Hirofumi TSUJINO, Kazuya NAGANO, Yasuo TSUTSUMI. Progesterone receptor membrane component 1 is a candidate key molecule involved EGFR-TKI resistance in lung adenocarcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B114. doi:10.1158/1535-7163.TARG-19-B114

Abstract B035: The role of αB-crystallin in chemotherapy-induced migration of triple negative breast cancer

Background: Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer marked by higher rate of metastasis and poorer overall survival. Although chemotherapy is the standard care of TNBC, clinical reports have shown that neoadjuvant chemotherapy treatment promoted metastasis in TNBC patients. Neoadjuvant chemotherapy-induced pro-metastasis in breast cancer cells was well explained by tumor microenvironment of metastasis, while its intracellular process has not been clarified yet. One of the small heat shock proteins, αB-crystallin, showed its high expression in metastatic sites of TNBC comparing to primary site, suggesting that αB-crystallin might be a potential target of metastasis. Even through researchers have also showed that αB-crystallin promoted tube formation, the relationship between αB-crystallin and chemotherapy-induced metastasis is not clear and the intracellular role of αB-crystallin needs to be explored. Purpose: To identify whether αB-crystallin involves in chemotherapy treatment and how αB-crystallin works in induced metastasis in this study. The expression of αB-crystallin in chemotherapy-induced TNBC migration were examined and its influence in Epithelial-Mesenchymal Transition (EMT) markers was confirmed. Methods: Cell viability of chemotherapy (Cisplatin, Fluorouracil, or Paclitaxel) in HCC1806 were tested by wst-8 assay. Preformed wound healing assay to measure migration ratio after treating HCC1806 cells with chemotherapy of three concentrations and confirming cell confluence. Expression level of αB-crystallin was examined after the same treatment, and the migration ability was measured when silencing αB-crystallin with small interfering RNA. Expression level of αB-crystallin and EMT markers were examined by western blotting after the same chemotherapy treatment. Results: The results of wst-8 assay showed that low concentrations of chemotherapy (0.01 μM and 0.1 μM of cisplatin, 0.01 μM and 0.1 μM of fluorouracil, 0.5 nM and 1 nM of paclitaxel) have no impact on cell viability of HCC1806, and high concentration of chemotherapy (1 μM of cisplatin, 1 μM of fluorouracil, 2 nM of paclitaxel) led to 80% alive cells comparing to non-treatment group. In addition, to identify the role of αB-crystallin in chemotherapy-induced migration, wound healing assay and western blotting were performed, showing that low concentration of chemotherapy treatment induced migration and promoted αB-crystallin expression, and that high concentration of chemotherapy blocked cell migration. Moreover, EMT markers were examined by western blotting after chemotherapy treatment, the increase of N-cadherin and decrease of E-cadherin were showed in HCC1806 after low concentration of chemotherapy treatment. Finally, to confirmed the relationship between αB-crystallin and chemotherapy-induced migration, wound healing assay was performed after silencing αB-crystallin and treating with chemotherapy. Silencing αB-crystallin reversed migration of HCC1806 cells and the expression of N-cadherin and E-cadherin induced by low concentrations of chemotherapy. Conclusion: These results suggest that the treatment of low concentrations of chemotherapy promoted epithelial to mesenchymal transition through increasing αB-crystallin expression, and induced migration in HCC1806.

Citation Format: Lili YANG, Kazuma HIGASHISAKA, Yuya HAGA, Naoki SEKINE, Kotoe KIYOMOTO, Ying LIN, Hirofumi TSUJINO, Kazuya NAGANO, Yasuo TSUTSUMI. The role of αB-crystallin in chemotherapy-induced migration of triple negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B035. doi:10.1158/1535-7163.TARG-19-B035

Melatonin Attenuates Chronic Cough Mediated by Oxidative Stress via Transient Receptor Potential Melastatin-2 in Guinea Pigs Exposed to Particulate Matter 2.5

The aim of this study was to investigate the effects of melatonin on oxidative stress, the expression of transient receptor potential melastatin-2 (TRPM2) in guinea pig brains, and the influence of melatonin on oxidative stress in lungs and airway inflammation induced by particulate matter 2.5 (PM2.5). A particle suspension (0.1 g/ml) was nasally administered to the guinea pigs to prepare a PM2.5 exposure model. Cough frequency and cough incubation period were determined through RM6240B biological signal collection and disposal system. Oxidative stress markers, including malondialdehyde (MDA), total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px), in the medulla oblongata were examined through spectrophotometer. Reactive oxygen species (ROS) were detected in the hypoglossal nucleus, cuneate nucleus, Botzinger complex, dorsal vagal complex, and airway through dihydroethidium fluorescence. Hematoxylin-eosin (HE) staining and substance P expression via immunohistochemistry revealed the inflammatory levels in the airway. TRPM2 was observed in the medulla oblongata through immunofluorescence and Western blot. The ultrastructure of the blood-brain barrier and neuronal mitochondria was determined by using a transmission electron microscope. Our study suggests that melatonin treatment decreased PM2.5-induced oxidative stress level in the brains and lungs and relieved airway inflammation and chronic cough. TRPM2 might participate in oxidative stress in the cough center by regulating cough.

A POROELASTIC MODEL FOR CELL CRAWLING INCLUDING MECHANICAL COUPLING BETWEEN CYTOSKELETAL CONTRACTION AND ACTIN POLYMERIZATION

Much is known about the biophysical mechanisms involved in cell crawling, but how these processes are coordinated to produce directed motion is not well understood. Here, we propose a new hypothesis whereby local cytoskeletal contraction generates fluid flow through the lamellipodium, with the pressure at the front of the cell facilitating actin polymerization which pushes the leading edge forward. The contraction, in turn, is regulated by stress in the cytoskeleton. To test this hypothesis, finite element models for a crawling cell are presented. These models are based on nonlinear poroelasticity theory, modified to include the effects of active contraction and growth, which are regulated by mechanical feedback laws. Results from the models agree reasonably well with published experimental data for cell speed, actin flow, and cytoskeletal deformation in migrating fish epidermal keratocytes. The models also suggest that oscillations can occur for certain ranges of parameter values.