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64


Chromium

Chapter by: Sun, Hong; Costa, Max
in: Handbook on the Toxicology of Metals by
[S.l.] : Elsevier Inc., 2021
pp. 197-220
ISBN: 9780128229460
CID: 5189452

RUNX2/miR‑31/SATB2 pathway in nickel‑induced BEAS‑2B cell transformation

Zhu, Yusha; Chen, Qiao Yi; Jordan, Ashley; Sun, Hong; Roy, Nirmal; Costa, Max
Nickel (Ni) compounds are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) and are known to be carcinogenic to the lungs. In our previous study, special AT‑rich sequence‑binding protein 2 (SATB2) was required for Ni‑induced BEAS‑2B cell transformation. In the present study, a pathway that regulates the expression of SATB2 protein was investigated in Ni‑transformed BEAS‑2B cells using western blotting and RT‑qPCR for expression, and soft agar, migration and invasion assays for cell transformation. Runt‑related transcription factor 2 (RUNX2), a master regulator of osteogenesis and an oncogene, was identified as an upstream regulator for SATB2. Ni induced RUNX2 expression and initiated BEAS‑2B transformation and metastatic potential. Previously, miRNA‑31 was identified as a negative regulator of SATB2 during arsenic‑induced cell transformation, and in the present study it was identified as a downstream target of RUNX2 during carcinogenesis. miR‑31 expression was reduced in Ni‑transformed BEAS‑2B cells, which was required to maintain cancer hallmarks. The expression level of miR‑31 was suppressed by RUNX2 in BEAS‑2B cells, and this increased the expression level of SATB2, initiating cell transformation. Ni caused the repression of miR‑31 by placing repressive marks at its promoter, which in turn increased the expression level of SATB2, leading to cell transformation.
PMID: 34109987
ISSN: 1791-2431
CID: 4924552

Identification of an 11-Autophagy-Related-Gene Signature as Promising Prognostic Biomarker for Bladder Cancer Patients

Zhou, Chaoting; Li, Alex Heng; Liu, Shan; Sun, Hong
BACKGROUND:Survival rates for highly invasive bladder cancer (BC) patients have been very low, with a 5-year survival rate of 6%. Accurate prediction of tumor progression and survival is important for diagnosis and therapeutic decisions for BC patients. Our study aims to develop an autophagy-related-gene (ARG) signature that helps to predict the survival of BC patients. METHODS:RNA-seq data of 403 BC patients were retrieved from The Cancer Genome Atlas Urothelial Bladder Carcinoma (TCGA-BLCA) database. Univariate Cox regression analysis was performed to identify overall survival (OS)-related ARGs. The Lasso Cox regression model was applied to establish an ARG signature in the TCGA training cohort (N = 203). The performance of the 11-gene ARG signature was further evaluated in a training cohort and an independent validation cohort (N = 200) using Kaplan-Meier OS curve analysis, receiver operating characteristic (ROC) analysis, as well as univariate and multivariate Cox regression analysis. RESULTS:. The ARGs-derived high-risk bladder cancer patients exhibited significantly poor OS in both training and validation cohorts. The prognostic model showed good predictive efficacy, with the area under the ROC curve (AUCs) for 1-year, 3-year, and 5-year overall survival of 0.702 (0.695), 0.744 (0.640), and 0.794 (0.658) in the training and validation cohorts, respectively. A prognostic nomogram, which included the ARGs-derived risk factor, age and stage for eventual clinical translation, was established. CONCLUSION/CONCLUSIONS:We identified a novel ARG signature for risk-stratification and robust prediction of overall survival for BC patients.
PMCID:8146553
PMID: 33925460
ISSN: 2079-7737
CID: 4897962

Induction of NUPR1 and AP‑1 contributes to the carcinogenic potential of nickel

Murphy, Anthony; Roy, Nirmal; Sun, Hong; Jin, Chunyuan; Costa, Max
Nickel (Ni) is carcinogenic to humans, and causes cancers of the lung, nasal cavity, and paranasal sinuses. The primary mechanisms of Ni‑mediated carcinogenesis involve the epigenetic reprogramming of cells and the ability for Ni to mimic hypoxia. However, the exact mechanisms of carcinogenesis related to Ni are obscure. Nuclear protein 1 (NUPR1) is a stress‑response gene overexpressed in cancers, and is capable of conferring chemotherapeutic resistance. Likewise, activator protein 1 (AP‑1) is highly responsive to environmental signals, and has been associated with cancer development. In this study, NUPR1 was found to be rapidly and highly induced in human bronchial epithelial (BEAS‑2B) cells exposed to Ni, and was overexpressed in Ni‑transformed BEAS‑2B cells. Similarly, AP‑1 subunits, JUN and FOS, were induced in BEAS‑2B cells following Ni exposure. Knockdown of JUN or FOS was found to significantly suppress NUPR1 induction following Ni exposure, demonstrating their importance in NUPR1 transactivation. Reactive oxygen species (ROS) are known to induce AP‑1, and Ni has been shown to produce ROS. Treatment of BEAS‑2B cells with antioxidants was unable to prevent NUPR1 induction by Ni, suggesting that NUPR1 induction by Ni relies on mechanisms other than oxidative stress. To determine how NUPR1 is transcriptionally regulated following Ni exposure, the NUPR1 promoter was cloned and inserted into a luciferase gene reporter vector. Multiple JUN binding sites reside within the NUPR1 promoter, and upon deleting a JUN binding site in the upstream most region within the NUPR1 promoter using site‑directed mutagenesis, NUPR1 promoter activity was significantly reduced. This suggests that AP‑1 transcriptionally regulates NUPR1. Moreover, knockdown of NUPR1 significantly reduced colony formation and anchorage‑independent growth in Ni‑transformed BEAS‑2B cells. Therefore, these results collectively demonstrate a novel mechanism of NUPR1 induction following Ni exposure, and provide a molecular basis by which NUPR1 may contribute to lung carcinogenesis.
PMCID:8365176
PMID: 33649793
ISSN: 1791-2431
CID: 5039082

Downregulation of hedgehog-interacting protein (HHIP) contributes to hexavalent chromium-induced malignant transformation of human bronchial epithelial cells

Li, Peichao; Zhang, Xiaoru; Murphy, Anthony J; Costa, Max; Zhao, Xiaogang; Sun, Hong
Hexavalent chromium [Cr(VI)] is a potent human lung carcinogen. Multiple mechanisms have been proposed that contribute to Cr(VI)-induced lung carcinogenesis including oxidative stress, DNA damage, genomic instability and epigenetic modulation. However, the molecular mechanisms and pathways mediating Cr(VI) carcinogenicity have not been fully elucidated. Hedgehog (Hh) signaling is a key pathway that plays important roles in the formation of multiple tissues during embryogenesis and in the maintenance of stem cell populations in adults. Dysregulation of Hh signaling pathway has been reported in many human cancers. Here, we report a drastic reduction in both mRNA and protein levels of hedgehog-interacting protein (HHIP), a downstream target and a negative regulator of Hh signaling, in Cr(VI)-transformed cells. These findings point to a potential role of Hh signaling in Cr(VI)-induced malignant transformation and lung carcinogenesis. Cr(VI)-transformed cells exhibited DNA hypermethylation and silencing histone marks in the promoter region of HHIP, indicating that an epigenetic mechanism mediates Cr(VI)-induced silencing of HHIP. In addition, the major targets of Hh signaling (GLI1-3 and PTCH1) were significantly increased in Cr(VI)-transformed cells, suggesting an aberrant activation of Hh signaling in these cells. Moreover, ectopically expressing HHIP not only suppressed Hh signaling but also inhibited cell proliferation and anchorage-independent growth in Cr(VI)-transformed cells. In conclusion, these findings establish a novel regulatory mechanism underlying Cr(VI)-induced lung carcinogenesis and provide new insights for developing a better diagnostic and prognostic strategy for Cr(VI)-related human lung cancer.
PMCID:7877560
PMID: 32710611
ISSN: 1460-2180
CID: 4809772

Longitudinal impact on rat cardiac tissue transcriptomic profiles due to acute intratracheal inhalation exposures to isoflurane

Park, Sung-Hyun; Lu, Yuting; Shao, Yongzhao; Prophete, Colette; Horton, Lori; Sisco, Maureen; Lee, Hyun-Wook; Kluz, Thomas; Sun, Hong; Costa, Max; Zelikoff, Judith; Chen, Lung-Chi; Cohen, Mitchell D
Isoflurane (ISO) is a widely used inhalation anesthetic in experiments with rodents and humans during surgery. Though ISO has not been reported to impart long-lasting side effects, it is unknown if ISO can influence gene regulation in certain tissues, including the heart. Such changes could have important implications for use of this anesthetic in patients susceptible to heart failure/other cardiac abnormalities. To test if ISO could alter gene regulation/expression in heart tissues, and if such changes were reversible, prolonged, or late onset with time, SHR (spontaneously hypertensive) rats were exposed by intratracheal inhalation to a 97.5% air/2.5% ISO mixture on two consecutive days (2 hr/d). Control rats breathed filtered air only. On Days 1, 30, 240, and 360 post-exposure, rat hearts were collected and total RNA was extracted from the left ventricle for global gene expression analysis. The data revealed differentially-expressed genes (DEG) in response to ISO (compared to naïve control) at all post-exposure timepoints. The data showed acute ISO exposures led to DEG associated with wounding, local immune function, inflammation, and circadian rhythm regulation at Days 1 and 30; these effects dissipated by Day 240. There were other significantly-increased DEG induced by ISO at Day 360; these included changes in expression of genes associated with cell signaling, differentiation, and migration, extracellular matrix organization, cell-substrate adhesion, heart development, and blood pressure regulation. Examination of consistent DEG at Days 240 and 360 indicated late onset DEG reflecting potential long-lasting effects from ISO; these included DEG associated with oxidative phosphorylation, ribosome, angiogenesis, mitochondrial translation elongation, and focal adhesion. Together, the data show acute repeated ISO exposures could impart variable effects on gene expression/regulation in the heart. While some alterations self-resolved, others appeared to be long-lasting or late onset. Whether such changes occur in all rat models or in humans remains to be investigated.
PMCID:8516213
PMID: 34648499
ISSN: 1932-6203
CID: 5046652

Polyadenylation of Histone H3.1 mRNA Promotes Cell Transformation by Displacing H3.3 from Gene Regulatory Elements

Chen, Danqi; Chen, Qiao Yi; Wang, Zhenjia; Zhu, Yusha; Kluz, Thomas; Tan, Wuwei; Li, Jinquan; Wu, Feng; Fang, Lei; Zhang, Xiaoru; He, Rongquan; Shen, Steven; Sun, Hong; Zang, Chongzhi; Jin, Chunyuan; Costa, Max
Replication-dependent canonical histone messenger RNAs (mRNAs) do not terminate with a poly(A) tail at the 3' end. We previously demonstrated that exposure to arsenic, an environmental carcinogen, induces polyadenylation of canonical histone H3.1 mRNA, causing transformation of human cells in vitro. Here we report that polyadenylation of H3.1 mRNA increases H3.1 protein, resulting in displacement of histone variant H3.3 at active promoters, enhancers, and insulator regions, leading to transcriptional deregulation, G2/M cell-cycle arrest, chromosome aneuploidy, and aberrations. In support of these observations, knocking down the expression of H3.3 induced cell transformation, whereas ectopic expression of H3.3 attenuated arsenic-induced cell transformation. Notably, arsenic exposure also resulted in displacement of H3.3 from active promoters, enhancers, and insulator regions. These data suggest that H3.3 displacement might be central to carcinogenesis caused by polyadenylation of H3.1 mRNA upon arsenic exposure. Our findings illustrate the importance of proper histone stoichiometry in maintaining genome integrity.
PMCID:7492993
PMID: 32920490
ISSN: 2589-0042
CID: 4615562

Where Are We and What Shall We Do Next? A Qualitative Study of the Quality of Home Care in Shanghai, China

Tang, Xianping; Chen, Xuemei; Wu, Bei; Ma, Chenjuan; Ge, Song; Sun, Hong; Zhou, Lanshu
Introduction: With the increasing need for home care in Shanghai, China, it is crucial to ensure its quality. This study aimed to explore quality-related issues of home care in Shanghai, China, and identify strategies for improvement. Method: This is a descriptive qualitative study. Semistructured interviews were conducted among 27 individuals, including home care managers (n = 8), nurses (n = 10), and patients and/or their caregivers (n = 9). Colaizzi's seven-step analysis method was used to guide data analysis. Results: Three themes emerged regarding the quality of home care in China: unsatisfactory structure quality, unsatisfactory process quality, and imperfect outcome quality evaluation system. Recommended strategies for quality improvement included issuing standards for home care evaluation, refining structure quality and process quality, and establishing an outcome quality evaluation system. Conclusions: Concerns about the quality of home care in China were identified by providers and patients. More research especially studies quantifying the care quality and its influencing factors are needed.
PMID: 32193999
ISSN: 1552-7832
CID: 4371962

Overexpressed miR-200a promotes bladder cancer invasion through direct regulating Dicer/miR-16/JNK2/MMP-2 axis

Yang, Rui; Xu, Jiheng; Hua, Xiaohui; Tian, Zhongxian; Xie, Qipeng; Li, Jingxia; Jiang, Guosong; Cohen, Mitchell; Sun, Hong; Huang, Chuanshu
Invasive bladder cancer (BC) is one of the most lethal malignant urological tumors. Although miR-200a has been reported as an onco-miRNA that targets the PTEN gene in endometrioid carcinoma, its biological significance in BC invasion has been poorly explored. In the current study, we found that miR-200a was markedly overexpressed in both human BC tissues and BBN-induced muscle-invasive BC tissues. We further showed that miR-200a overexpression specifically promoted human BC cell invasion, but not migration, via transcriptional upregulation of matrix metalloproteinase (MMP)-2. Mechanistic studies indicated that the increased phosphorylation of c-Jun mediated the increasing levels of MMP-2 mRNA transcription. Further investigation revealed that Dicer was decreased in miR-200a overexpressed BC cells; this resulted in inhibition of miR-16 maturation and consequently led to increased JNK2 protein translation and c-Jun activation. Taken together, the studies here showed that miR-200a overexpression inhibited Dicer expression, in turn, resulted in inhibition of miR-16 maturation, leading to upregulation of JNK2 expression, c-Jun phosphorylation, MMP-2 transcription and, ultimately, BC invasion. Collectively, these results demonstrate that miR-200a is an onco-miRNA that is a positive regulator for BC invasion. This finding could be very useful in the ongoing development of new strategies to treat invasive BC patients.
PMID: 31772330
ISSN: 1476-5594
CID: 4215972

Chromium

Chapter by: Sun, Hong; Cohen, Mitchell D
in: Environmental toxicants : human exposures and their health effects by Lippmann, Morton; Leikauf, George D (Eds)
Hoboken, NJ : Wiley, 2020
pp. 487-513
ISBN: 9781119438915
CID: 4584072