Interaction of Polystyrene Nanoplastics and Helicobacter pylori Modulates Gastric Cancer Cellular Functions and Metastasis

Interaction of Polystyrene Nanoplastics and Helicobacter pylori Modulates Gastric Cancer Cellular Functions and MetastasisAbstract: Nanoplastics (NPs), an emerging pollutant, can accumulate in human digestive tissues and pose health risks. Chronic Helicobacter pylori (H. pylori) infection, the main cause of gastric cancer (GC), accounts for about 75% of cases. This study aimed to investigate whether polystyrene nanoplastics (PS-NPs) and H. pylori can enter gastric cancer cells and assess the effects of their combined exposure on cell proliferation, apoptosis, autophagy, and metastasis. In vitro, PS-NPs were co-cultured with H. pylori. A liver metastasis model was established by pre-exposing HGC-27 cells to PS-NPs or co-exposing them to PS-NPs and H. pylori, which were then injected into nude mice. Scanning electron microscopy (SEM) demonstrated that PS-NPs adhered to the bacterial surface. Exposure to 100 μg/mL PS-NPs for 24 hours significantly inhibited bacterial growth and increased intracellular reactive oxygen species (ROS) levels. When gastric cancer cell line HGC-27 was co-exposed to PS-NPs and H. pylori, both agents enteralized the cells, leading to increased cytotoxicity, reduced viability and proliferation, increased apoptosis, decreased mitochondrial membrane potential, and increased autophagosome formation. Interestingly, in vivo, combined exposure exhibited an antagonistic effect: while PS-NPs alone promoted liver and lung metastasis, tumor cell proliferation, and hepatic lesions, the combination with H. pylori partially attenuated these effects, reducing tumor growth and metastasis. This study provides valuable insights into the development of gastric cancer and identifies emerging pollutants associated with infection. PS-NPs attach to bacteria and enter cancer cells, modulating multiple cellular processes; however, their effects may differ between isolated cellular models and whole-organism contexts, highlighting the importance of considering both in vitro and in vivo systems when assessing the potential health risks of NPs in the gastrointestinal environment.Conclusion: This study systematically determined the effects of PS-NPs and H. pylori on gastric cancer cells HGC-27 and a model of tissue metastasis. We showed that PS-NPs induce ROS in H. pylori, form nanoparticle–bacteria complexes, and co-internalized with gastric cancer cells, leading to increased cytotoxicity, reduced cell viability and proliferation, and enhanced mitochondrial dysfunction, apoptosis, and autophagy. In vivo, PS-NPs or H. pylori aggravated liver and lung metastasis and tissue damage, while short-term co-exposure partially inhibited tumor growth and hepatocyte and lung damage. These findings suggest that PS-NPs may act as pathogen carriers in the gastrointestinal environment, thereby amplifying cytotoxic and autophagic responses; however, their in vivo impact involves complex regulatory mechanisms that may contribute to potential gastric cancer progression. Our results suggest a potential influence of NPs on gastric carcinogenesis and reveal an interaction between environmental pollutants and pathogenic infection, which warrants further validation using longitudinal exposure models and epidemiological studies to better inform gastric cancer prevention strategies.Data description:Figure 1: Panels A1–A3 show the morphology of PS-NPs at 1 μm, 500 nm, and 200 nm, respectively, imaged using TEM. Particle sizes were measured using ImageJ software and exported to Excel for statistical analysis. Mean particle size and standard deviation were calculated. Panel A4 presents the particle size distribution graph plotted based on the measurements. Panel B shows the FTIR spectra of PS-NPs, with raw data stored in folder B and plotted accordingly. Panel C Hydrodynamic diameter distribution of polystyrene nanoparticles determined by dynamic light scattering. Panel D shows the zeta potential distribution of polystyrene nanoparticles. Specific values can be seen in the Zata potentials and DLSexcel tables, presented as mean ± standard deviation (n = 3).Figure 2: Panels A1 and A2 display SEM images illustrating the adhesion of PS-NPs to Helicobacter pylori. Panels B1–B3 show TEM images of intracellular localization of H. pylori, PS-NPs, and co-localization of both.Figure 3: Panel A depicts the survival curve of H. pylori, generated using Prism software based on absorbance data measured with a microplate reader. Each group includes three replicates; raw data and graphing files are provided in the corresponding folder. Panel B shows the intracellular ROS levels in three experimental groups. Panel C compares ROS levels between the H. pylori group and the H. pylori + PS-NPs group. All raw data are provided in Excel format, with triplicate wells per group, and the mean ± SD were calculated. Corresponding graphing software files are also included.Figure 4: Panel A shows CCK-8 assay results. The associated raw data and graphing files are available in the folder. Group abbreviations: Control (C), H. pylori (Hp), PS-NPs (PS). Panel B presents representative images from each group; proliferating cells were quantified using ImageJ, and data are compiled in Excel with replicates per group. Mean values and standard deviations were calculated. Panel C includes quantitative data and corresponding graphing files with consistent naming.Figure 5: Panel A presents summary results for each group, shown as publication-ready figures. Quantitative data were analyzed using ImageJ and are compiled in Excel file B. Each group includes replicate measurements, and the relevant graphing software is included. Panel D shows flow cytometry analysis results with three replicates per group, labeled as 1, 2, and 3. Data are summarized in Excel file C, including mean and standard deviation calculations, and the corresponding graphing software is labeled as Software C.Figure 6: For all panels labeled A, images were captured using TEM. Group abbreviations are as follows: Control (C), H. pylori (Hp), and PS-NPs (PS). Red arrows indicate double-membrane autophagosomes containing relatively intact cytoplasmic material or organelles, while yellow arrows indicate single-membrane autolysosomes formed by the fusion of autophagosomes with lysosomal membranes (Scale bar: 1 μm).Figure 7: Panel A shows representative images of each group captured by confocal laser scanning microscopy. Only publication-quality images are presented in the file. Quantitative data were analyzed using ImageJ and recorded in Excel files B and C. Each group includes replicates, and data are summarized with mean and standard deviation. Panels B and C show quantitative analyses of autophagosomes and autolysosomes, respectively, with corresponding graphing software named B and C.Figure 8: Panel A shows macroscopic images of liver tissues from each group. Panel B presents H&E staining of liver sections.Figure 9: Panel A shows immunohistochemical staining of Ki67 for each group. Quantitative analysis was performed using ImageJ, and data are recorded in Excel file B. The comparison chart in Panel B was generated using graphing software B. Panel C presents T2-weighted MRI scans of each group.Figure S1 shows the original images of laser confocal microscopy at 12, 24, and 48 hours, respectively, and they are stored in three folders. The specific analysis values are placed in an Excel table, and the statistical graphs were created by GraphPad Prism.Figure S2 presents the results of Western blot analysis of the apoptosis-related proteins Caspase-3, Cleaved Caspase-3, PARP, and Cleaved PARP in HGC-27 cells. The original images are stored in a file, each folder has the corresponding pre-exposure, post-exposure, and final photos, and the specific results are in the Excel table. The graphs were plotted from the numerical values by GraphPad Prism software.Figure S3 shows the histological analysis of lung and kidney tissues through H&E staining. The original images of the tissues are in the corresponding folders. (A) The lung tissue shows that cancer cells have metastasized within the lung parenchyma (as indicated by the red arrows). (B) All groups of kidney tissues show normal structures.