Smith Joycelyn, Neupane Rajendra, McAmis William, Singh Udai, Chatterjee Saurabh, Raychoudhury Samir
Department of Biology, Chemistry, and Environmental Health Science, Benedict College, 1600 Harden Street, Columbia, SC, 29204, USA.
School of Medicine, University of South Carolina, Columbia, SC, USA.
Toxicol Rep. 2019 Nov 6;6:1176-1181. doi: 10.1016/j.toxrep.2019.11.006. eCollection 2019.
Polycyclic Aromatic Hydrocarbons (PAHs) are environmental pollutants. The present study compares the toxic effects of BaP alone and a mixture of PAHs on human breast cancer cells. We hypothesize that PAH mixture is more toxic than BaP alone, and an increased NOX2 activation is related to PAH-induced oxidative stress. Initially, we exposed cultured human breast cancer cells to BaP alone (125 ng/mL and 500 ng/mL) and a mixture of PAHs (125 ng/mL and 500 ng/mL). After 24 h of exposure, the PAH mixture demonstrated a significant () reduction in cell viability. The higher concentration of BaP alone (500 ng/mL) and both 125 ng/mL and 500 ng/mL PAH mixture significantly ) increased lactate production by MDA-MB-231 cells. We had observed an identical level of increased lactate levels when the cells were exposed to PAHs for 48 h. Flow cytometric analysis revealed that only PAHs mixture (both 125 ng/mL and 500 ng/mL) suppressed S phase significantly (). Finally, immunofluorescence microscopy was undertaken to examine the role of NOX2 due to PAHs toxicity. Colocalization of GP91phox and P47phox, a hallmark of NOX2 activation in the cell membrane of macrophage Kupffer cells demonstrated that higher concentration of BaP or PAH mixture showed increased colocalization events. These data suggest that the mixture of PAHs is more toxic and perturbing to DNA synthesis than BaP alone in cultured cells, and the toxicity is accompanied by NOX2 activation. Thus PAHs can lead to the increased burden of oxidative stress and alter the cellular redox status.
多环芳烃（PAHs）是环境污染物。本研究比较了单独的苯并[a]芘（BaP）和多环芳烃混合物对人乳腺癌细胞的毒性作用。我们假设多环芳烃混合物比单独的BaP毒性更大，并且NOX2激活增加与多环芳烃诱导的氧化应激有关。最初，我们将培养的人乳腺癌细胞暴露于单独的BaP（125 ng/mL和500 ng/mL）和多环芳烃混合物（125 ng/mL和500 ng/mL）中。暴露24小时后，多环芳烃混合物显示细胞活力显著（）降低。单独的较高浓度BaP（500 ng/mL）以及125 ng/mL和500 ng/mL的多环芳烃混合物均显著（）增加了MDA-MB-231细胞的乳酸生成。当细胞暴露于多环芳烃48小时时，我们观察到乳酸水平有相同程度的升高。流式细胞术分析显示，只有多环芳烃混合物（125 ng/mL和500 ng/mL）显著（）抑制了S期。最后，进行免疫荧光显微镜检查以研究由于多环芳烃毒性导致的NOX2的作用。GP91phox和P47phox的共定位是巨噬细胞库普弗细胞膜中NOX2激活的标志，表明较高浓度的BaP或多环芳烃混合物显示共定位事件增加。这些数据表明，在培养的细胞中，多环芳烃混合物比单独的BaP对DNA合成更具毒性且干扰更大，并且这种毒性伴随着NOX2激活。因此，多环芳烃可导致氧化应激负担增加并改变细胞氧化还原状态。
