The increasing presence of secondary micro/nanoplastics (MNPLs) in the environment requires knowing if they represent a real health concern. To such end, an important point is to test representative MNPLs such as the denominated true-to-life MNPLs, resulting from the degradation of plastic goods in lab conditions. In this study, we have used polyethylene terephthalate (PET) NPLs resulting from the degradation of PET water bottles. Since inhalation is an important exposure route to environmental MNPLS, we have used mouse alveolar macrophages (MH-S) as a target cell, and the study focused only on the cells that have internalized them. This type of approach is novel as it may capture the realistic adverse effects of PETNPLs only in the internalized cells, thereby mitigating any biases while assessing the risk of these MNPLs. Furthermore, the study utilized a set of biomarkers including intracellular reactive oxygen species (ROS) levels, variations on the mitochondrial membrane potential values, and the macrophage polarization to M1 (pro-inflammatory response) and M2 (anti-proinflammatory response) as possible cellular effects due to PETNPLs in only the cells that internalized PETNPLs. After exposures lasting for 3 and 24 h to a range of concentrations (0, 25, 50, and 100 μg/mL) the results indicate that no toxicity was induced despite the 100% internalization observed at the highest concentration. Significant intracellular levels of ROS were observed, mainly at exposures lasting for 24 h, in an indirect concentration-effect relationship. Interestingly, a reduction in the mitochondrial membrane potential was observed, but only at exposures lasting for 24 h, but without a clear concentration-effect relationship. Finally, PETNPL exposure shows a significant polarization from M0 to M1 and M2 subtypes. Polarization to M1 (pro-inflammatory stage) was more marked and occurred at both exposure times. Polarization to M2 (anti-inflammatory stage) was only observed after exposures lasting for 24 h. Due to the relevance of the described biomarkers, our results underscore the need for further research, to better understand the health implications associated with MNPL exposure.

TBX15 is a T-box transcription factor essential for development, also proposed as a marker in prostate cancer; and, recently, its antiapoptotic function indicates a role in carcinogenesis. Regulation of TBX15 is uncovered. In this study, we investigated the regulation of TBX15 expression in human cancer cells, by analyzing the regulatory function of a 5’-distal conserved region of TBX15. Bisulfite sequencing showed high methylation of the CpG island contained in this region that was not correlated with TBX15 mRNA levels, in the cancer cell lines analyzed; however, after 5-aza-dC treatment of TPC-1 cells an increase of TBX15 expression was observed. We also found a significant response of TBX15 to TNF-α activation of the NF-κB pathway using five cancer cell lines, and similar results were obtained when NF-κB was activated with PMA/ionomycin. Next, by luciferase reporter assays, we identified the TBX15 regulatory region containing two functional NF-κB binding sites with response to NF-κBp65, mapping on the -3302 and -3059 positions of the TBX15 gene. Moreover, a direct interaction of NF-κBp65 with one of the two NF-κB binding sites was indicated by ChIP assays. In summary, we provide novel data showing that NF-κB signaling up-regulates TBX15 expression in cancer cells. Furthermore, the link between TBX15 and NF-κB found in this study may be important to understand cancer and development processes.

Yin Yang 1 (YY1) is a transcription factor that plays an important role during all stages of B cell differentiation. Several studies reported upregulation of YY1 in B cell derived lymphoma, indicating that it might act as an oncogene. Furthermore, aberrant YY1 expression has been associated with survival in some entities of B cell non-Hodgkin lymphoma (B-NHL), suggesting that YY1 could be a valuable biomarker in B-NHL. However, studies are controversial and methodologically disparate, partially because some studies are based on transcript levels while others rely on YY1 protein data. Therefore, we aimed to investigate the dependence of YY1 protein levels on YY1 transcription. A panel of human cell lines representing different B-NHL subtypes was used to test for the correlation of YY1 mRNA and protein levels which were determined by quantitative PCR and immunoblotting. To analyze YY1 mRNA and YY1 protein stability cells were treated with actinomycin-D and cycloheximide, respectively. siRNAs were transfected to knockdown YY1. Kaplan-Meier survival analyses were performed with data from published patient cohorts. Pearson’s correlation analyses were assessed and statistical power was examined by Student’s t-test. In the analyzed panel of B-NHL cell lines YY1 transcript levels do not correlate with their cellular protein amounts. YY1 protein levels were unaffected by transient block of transcription or by targeting YY1 mRNA using siRNA. Additionally, global inhibition of translation up to 48 h did not alter protein levels of YY1, indicating that YY1 is a highly stable protein in B-NHL. Furthermore, in a retrospective analysis of two different B-NHL cohorts, YY1 transcript levels had no impact on patients’ survival probabilities. Our results point out the necessity to focus on YY1 protein expression to understand the potential role of YY1 as an oncogene and to unravel its suitability as clinical biomarker in B-NHL.

In the environment, plastic waste degrades into small particles known as microplastics and nanoplastics (MNPLs), depending on their size. Given the potential harmful effects associated with MNPL exposure, it is crucial to develop environmentally representative particles for hazard assessment. These so-called true-to-life MNPLs are generated through in-house degradation of real-world plastic products. In this study, we produced titanium-doped nanoplastics (NPLs) from opaque polyethylene terephthalate (PET) milk bottles, which contain titanium dioxide as a filler. The resulting PET(Ti)-NPLs were thoroughly characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), mass spectrometry (MS), dynamic light scattering (DLS), ζ-potential measurements, transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. Human-derived THP-1 monocytes were employed to investigate particle uptake kinetics, dosimetry, and genotoxicity. A combination of flow cytometry and inductively coupled plasma mass spectrometry (ICP-MS) enabled the quantification of internalized particles, while the comet assay assessed DNA damage. The results revealed dose- and time-dependent effects of PET(Ti)-NPLs on THP-1 cells, particularly in terms of internalization. Titanium doping facilitated detection and influenced genotoxic outcomes. This study demonstrates the relevance of using environmentally representative nanoplastic models for evaluating human health risks and underscores the importance of further mechanistic research.