Determination of tipping point in course of PM2.5 organic extracts-induced malignant transformation by dynamic network biomarkers

New insights into the function and mechanisms of piRNA PMLCPIR in promoting PM2.5-induced lung cancer

INTRODUCTION

Extensive studies have established the correlation between long-term PM2.5 exposure and lung cancer, yet the mechanisms underlying this association remain poorly understood. PIWI-interacting RNAs (piRNAs), a novel category of small non-coding RNAs, serve important roles in various diseases. However, their biological function and mechanism in PM2.5-induced lung cancer have not been thoroughly investigated.

OBJECTIVES

We aimed to explore the oncogenic role of piRNA in lung cancer induced by PM2.5 exposure, as well as the underlying mechanisms.

METHODS

We conducted a PM2.5-induced human lung epithelial cell malignant transformation model. Human samples were used to further verify the finding. In vitro proliferation, migration, and invasion assays were performed to study the function of piRNA. RNA-sequencing was used to elucidate the the mechanisms of how piRNA mediates cell functions. PiRNA pull-down and computational docking analysis were conducted to identify proteins that binding to piRNA. In vivo experiments were used to explore whether inhibition of PMLCPIR could have a therapeutic effect on lung cancer.

RESULTS

We identified a new up-regulated piRNA, termed PM2.5-induced lung cancer up-regulation piRNA (PMLCPIR), which promotes the proliferation of PM2.5-transformed cells and lung cancer cells. RNA sequencing revealed ITGB1 as a downstream target of PMLCPIR. Importantly, PMLCPIR binds to nucleolin (NCL) and increases the expression of its target gene, ITGB1, thereby activating PI3K/AKT signaling. The inhibition of PMLCPIR could promote apoptosis in lung cancer cells and enhance their chemosensitivity to anti-tumor drugs.

CONCLUSION

We systematically identified the alterations of piRNA expression profiles in the PM2.5-induced malignant transformation model. Then, PMLCPIR was recognized as a novel oncogenic piRNA in PM2.5-induced lung cancer. Mechanically, PMLCPIR binds to NCL, enhancing ITGB1 expression and activating the ontogenetic PI3K/AKT signaling, potentially contributing to lung cancer progression. This study provides novel insights into the revelation of a new epigenetic regulator in PM2.5-induced lung cancer.

piR-27222 mediates PM2.5-induced lung cancer by resisting cell PANoptosis through the WTAP/m6A axis

PM2.5 pollution has been associated with the incidence of lung cancer, but the underlying mechanism is still unclear. PIWI-interacting RNAs (piRNAs), initially identified in germline cells, have emerged as a novel class of small non-coding RNAs (26 - 32 nucleotides) with diverse functions in various diseases, including cancer. However, the role and mechanism of piRNAs in the development of PM2.5-induced lung cancer remain to be clarified. In the presented study, we used a PM2.5-induced malignant transformation cell model to analyze the change of piRNA profiles. Among the disturbed piRNAs, piR-27222 was identified as an oncogene that inhibited cell death in a m6A-dependent manner. Mechanistically, we found that piR-27222 could deubiquitinate and stabilize eIF4B by directly binding to eIF4B and reducing its interaction with PARK2. The enhanced expression of eIF4B, in turn, promoted the expression of WTAP, leading to increased m6A modification in the Casp8 transcript. Consequently, the stability of Casp8 transcripts was reduced, rendering lung cancer cells resistant to PANoptosis. Collectively, our findings reveal that PM2.5 exposure up-regulated piR-27222 expression, which could affect EIF4B/WTAP/m6A axis, thereby inhibiting PANoptosis of cells and promoting lung cancer. Our study provides new insights into understanding the epigenetic mechanisms underlining PM2.5-induced lung cancer.

Exhaled VOC Biomarkers from Rats Injected with PMs from Thirty-One Major Cities in China

Particulate matter (PMs) of different origins can cause diverse health effects. Here, a homemade box was used to facilitate real-time measurements of breath-borne volatile organic compounds (VOCs) by gas chromatography-ion mobility spectrometry. We have tracked exhaled VOC changes in 228 Wistar rats that were injected with water-soluble PM suspension filtrates (after 0.45 μm) from 31 China cities for 1 h to up to 1-6 days during the experiments. Rats exposed to the filtrates exhibited significant changes in breath-borne VOCs within hours, featuring dynamic fluctuations in the levels of acetone, butan-2-one, heptan-2-one-M, acetic acid-M, and ethanol. Subsequently, on the fifth to sixth day after the injection, there was a notable increase in the proportion of aldehydes (including hexanal-M, hexanal-D, pentanal, heptanal-M, and (E)-2-hexenal). The 10 dynamic VOC fingerprint patterns mentioned earlier showcased the capability to indirectly differentiate urban PM toxicity and categorize the 31 cities into four distinct groups based on their health effects. This study provides valuable insights into the mechanisms of exhaled VOCs and underscores their critical role as biomarkers for differentiating the toxicity of different PMs and detecting the early signs of potential diseases. The results from this work also provide a scientific basis for city-specific air pollution control and policy development.

A2aR on lung adenocarcinoma cells: A novel target for cancer therapy via recruiting and regulating tumor-associated macrophages

Adenosine 2a receptor (A2aR), a typical GPCR with a high affinity for adenosine, is widely expressed on immune cells, inhibiting anti-tumor immune response accordingly. Here, we identify that A2aR is specifically expressed on tumor cells from lung adenocarcinoma (LUAD) patients, closely related to their prognosis and positively correlated with tumor-associated macrophages (TAMs) infiltration. We hypothesize that blocking A2aR on LUAD cells will inhibit the role of TAMs and control tumor growth. Constructing models of TAMs and LUAD mice, we find that A2aR highly expressed on LUAD cells promotes the secretion of chemokines and polarizing factors through activating PI3K/AKT/NF-κB pathway, thereby promoting the migration and invasion of TAMs. Functionally, blocking A2aR significantly suppresses TAMs infiltration and attenuates tumor burden in LUAD mice. Notably, the M2 polarization of TAMs can also be prevented by inhibiting A2aR in vitro. Together, our studies demonstrate that A2aR on LUAD cells drives TAMs migration and polarization, and blockade of A2aR may support a novel and potent therapeutic option for LUAD.

Long-term DEHP/MEHP exposure promotes colorectal cancer stemness associated with glycosylation alterations

Plasticizers are considered as environmental pollution released from medical devices and increased potential oncogenic risks in clinical therapy. Our previous studies have shown that long-term exposure to di-ethylhexyl phthalate (DEHP)/mono-ethylhexyl phthalate (MEHP) promotes chemotherapeutic drug resistance in colorectal cancer. In this study, we investigated the alteration of glycosylation in colorectal cancer following long-term plasticizers exposure. First, we determined the profiles of cell surface N-glycomes by using mass spectrometry and found out the alterations of α2,8-linkages glycans. Next, we analyzed the correlation between serum DEHP/MEHP levels and ST8SIA6 expression from matched tissues in total 110 colorectal cancer patients. Moreover, clinical specimens and TCGA database were used to analyze the expression of ST8SIA6 in advanced stage of cancer. Finally, we showed that ST8SIA6 regulated stemness in vitro and in vivo. Our results revealed long-term DEHP/MEHP exposure significantly caused cancer patients with poorer survival outcome and attenuated the expression of ST8SIA6 in cancer cells and tissue samples. As expected, silencing of ST8SIA6 promoted cancer stemness and tumorigenicity by upregulating stemness-associated proteins. In addition, the cell viability assay showed enhanced drug resistance in ST8SIA6 silencing cells treated with irinotecan. Besides, ST8SIA6 was downregulated in the advanced stage and positively correlated with tumor recurrence in colorectal cancer. Our results imply that ST8SIA6 potentially plays an important role in oncogenic effects with long-term phthalates exposure.

Overview of PM2.5 and health outcomes: Focusing on components, sources, and pollutant mixture co-exposure

PM_2.5 varies in source and composition over time and space as a complicated mixture. Consequently, the health effects caused by PM_2.5 varies significantly over time and generally exhibit significant regional variations. According to numerous studies, a notable relationship exists between PM_2.5 and the occurrence of many diseases, such as respiratory, cardiovascular, and nervous system diseases, as well as cancer. Therefore, a comprehensive understanding of the effect of PM_2.5 on human health is critical. The toxic effects of various PM_2.5 components, as well as the overall toxicity of PM_2.5 are discussed in this review to provide a foundation for precise PM_2.5 emission control. Furthermore, this review summarizes the synergistic effect of PM_2.5 and other pollutants, which can be used to draft effective policies.

Dynamic network biomarker to determine the critical point of breast cancer stage progression

BACKGROUND

The discovery of early warning signs and biomarkers in patients with early breast cancer is crucial for the prevention and treatment of breast cancer. Dynamic Network Biomarker (DNB) is an approach based on nonlinear dynamics theory, which we exploited to identify a set of DNB members and their key genes as early warning signals during breast cancer staging progression.

METHODS

First, based on the gene expression profile of breast cancer in the TCGA database, the DNB algorithm was used to calculate the composite index (CI) of each gene cluster in the process of breast cancer anatomical staging. Then we calculated gene modules associated with the clinical phenotype stage based on weighted gene co-expression network analysis (WGCNA), combined with DNB membership to identify key genes in the network.

RESULTS

We identified a set of gene clusters with the highest CI in Stage II as DNBs, whose roles in related pathways indicate the emergence of a tipping point and impact on breast cancer development. In addition, analysis of the key gene GPRIN1 showed that high expression of GPRIN1 predicts poor prognosis, and related immune analysis showed that GPRIN1 is involved in the development of breast cancer through immune aspects.

CONCLUSION

The discovery of DNBs and the key gene GPRIN1 can provide potential biomarkers and therapeutic targets for breast cancer.

Using a human bronchial epithelial cell-based malignant transformation model to explore the function of hsa-miR-200 family in the progress of PM2.5-induced lung cancer development

Numerous studies have revealed that ambient long-term exposure to fine particulate matter (PM_2.5) is significantly related to the development of lung cancer, but the molecular mechanisms of PM_2.5 exposure-induced lung cancer remains unknown. As an important epigenetic regulator, microRNAs (miRNAs) play vital roles in responding to environment exposure and various diseases including lung cancer development. Here we constructed a PM_2.5-induced malignant transformed cell model and found that miR-200 family, especially miR-200a-3p, was involved in the process of PM_2.5 induced lung cancer. Further investigation of the function of miR-200 family (miR-200a-3p as a representative revealed that miR-200a-3p promoted cell migration by directly suppressing TNS3 expression. These results suggested that ambient PM_2.5 exposure may increase the expression of miR-200 family and then promote the proliferation and migration of lung cancer cells. Our study provided novel model and insights into the molecular mechanism of ambient PM_2.5 exposure-induced lung cancer.

Polluting characteristics, sources, cancer risk, and cellular toxicity of PAHs bound in atmospheric particulates sampled from an economic transformation demonstration area of Dongguan in the Pearl River Delta, China

The Songshan Lake Science and Technology Industrial Park is a national economic transition demonstration area, which centers at a traditional industrial region, in Dongguan, China. We were interested in the involved atmospheric particulates-bound PAHs regarding their sources, cancer risk, and related cellular toxicity for those in other areas under comparable conditions. In this study, the daily concentrations of TSP, PM₁₀, and PM_2.5 were averaged 127.95, 95.91, and 67.62 μg/m³, and the bound PAHs were averaged 1.31, 1.22, and 0.77 ng/m³ in summer and 12.72, 20.51 and 40.27 ng/m³ in winter, respectively. The dominant PAHs were those with 5-6 rings, and 4-6 rings in summer and winter, respectively. The incremental lifetime cancer risk (ILCR) (90th percentile probability) of total PAHs was above 1.00E-06 in each age group, particularly high in adolescents. Sensitivity analysis indicated that slope factor and body weight had greater impact than exposure duration and inhalation rate on the ILCR. Moreover, treatment of human bronchial epithelial BEAS-2B cells with mixed five indicative PAHs increased the formation of ROS, DNA damage (elevation in γ-H2AX), and protein levels of CAR, PXR, CYP1A1, 1A2, 1B1, while reduced the AhR protein, with the winter mixture more potent than summer. For the sources of PAHs, the stable carbon isotope ratio analysis and diagnostic ratios consistently pointed to petroleum and fossil fuel combustion as major sources. In conclusion, our findings suggest that particulates-bound PAHs deserve serious concerns for a cancer risk in such environment, and the development of new power sources for reducing fossil fuel combustion is highly encouraged.