SEGH Articles

Chronic cadmium exposure promotes nasopharyngeal carcinoma progression and radioresistance

24 January 2019
Dr Lin Peng and her team investigate how environmental pollutant exposure influences the risk of cancer development and therapeutic resistance at the Clinical Laboratory, Cancer Hospital of Shantou University Medical College, China.

Dr Lin Peng, Associate Chief Physician, works in Clinical Laboratory, Cancer Hospital of Shantou University Medical College in China. The research team she leads focuses on environmental pollutant exposure and the risk of cancer development and therapeutic resistance. Her team has recently published research results highlighting the association between cadmium and breast cancer, connecting gastrointestinal cancer risk to cadmium and lead exposure and the association of polychlorinated biphenyls/polybrominated diphenyl ethers with breast cancer risk.

Lin Peng analysing blood samples

Lin Peng analysing blood samples

Nasopharyngeal carcinoma (NPC) is a unique malignancy with a high prevalence in East and Southeast Asia, especially in southern China. The unique ethnic and geographical distribution of NPC indicates hereditary factor and environmental factors may contribute to its unusual etiology. But to date, only nitrosamine, polycyclic aromatic hydrocarbons and nickel are regarded as environmental risk factors in the development and progression of NPC. Cadmium is a ubiquitous carcinogenic pollutant related with some human cancers. The aim of the present study was to evaluate the association between chronic low-concentration cadmium exposure and NPC progression and radiosensitivity.

Hospital-based 134 NPC cases and 132 cancer-free controls were recruited, the blood cadmium levels of whom were detected by graphite furnace atomizer absorption spectrophotometer and the basic clinical data and demographic characteristics were collected. To further confirm the effect of cadmium on NPC progression and radiosensitivity in vitro and in vivo, NPC cell lines CNE-1 and CNE-2 were continuously exposed with 1 μM cadmium chloride for 10 weeks. MTT assay, colony formation assay and xenograft tumor growth were used to assess cell viability and radiosensitivity. Transwell assays were performed to detect cell invasion and migration. The median concentration of blood cadmium in cases (3.84, IQR 2.21–6.10) was found significantly higher than that of controls (2.28, IQR 1.79–3.45) (P<0.001). Meanwhile, blood cadmium levels were positively associated with clinical stages and N classification (r=0.193, 0.187, respectively, P<0.05). MTT assay and colony formation assays showed that the cell proliferation in cadmium exposed NPC cells was significantly increased compared to the parental cells (P<0.05). Also, the invasive and migrative capacity of cadmium-treated NPC cells was markedly increased over 1.40-(P<0.01) and 1.30-(P<0.01) fold of the controls, respectively. In particular, xenograft tumours with cadmium-treated NPC cells exhibited increased tumour growth and radioresistance compared to transplanted controls(P<0.05). These results reveal the stimulative effect of chronic low-dose cadmium exposure on malignant progression and radioresistance of NPC for the first time.

 Lin Peng at the 34th International Conference of SEGH in Livingstone, Zambia

Lin Peng at the 34th SEGH International Conference in Livingstone, Zambia

 Lin Peng1,2,, Yi-Teng Huang3, Jiong-Yu Chen4*, Xia Huo5*

1 Clinical Laboratory, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou 515041, PR China.

2 Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, No. 22 Xinling Road, Shantou 515041, PR China.

3 Health Care Center, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China.

4 Oncological Research Lab, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou 515031, PR China.

5 Laboratory of Environmental Medicine and Developmental Toxicology, Guangzhou and Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, PR, China

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Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

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    Graphic abstract

  • Plasticizers and bisphenol A in Adyar and Cooum riverine sediments, India: occurrences, sources and risk assessment 2020-01-23


    Adyar and Cooum, the two rivers intersecting Chennai city, are exposed to serious pollution due to the release of large quantities of dumped waste, untreated wastewater and sewage. Sediments can act as repository for emerging organic contaminants. Hence, we have monitored the occurrence and risk associated with plasticizers [six phthalic acid esters (PAEs), bis(2-ethyl hexyl adipate) (DEHA)] and bisphenol A (BPA) in surface riverine sediments of Adyar and Cooum rivers from residential/commercial, industrial and electronic waste recycling sites. Σ7plasticizers (PAEs + DEHA) in the Adyar riverine sediment (ARS) and Cooum riverine sediment (CRS) varied between 51.82–1796 and 28.13–856 ng/g, respectively. More than three-fourth of Σ7plasticizers came from bis(2-ethylhexyl) phthalate (DEHP), in accordance with the high production and usage of this compound. BPA varied between 10.70–2026 and 7.58–1398 ng/g in ARS and CRS, respectively. Average concentrations of plasticizers and BPA were four times higher in electronic waste (e-waste) recycling sites when compared with industrial and residential/commercial sites. BPA and DEHP showed a strong and significant correlation (R2 = 0.7; p < 0.01) in the e-waste sites thereby indicating common source types. Sites present at close proximity to raw sewage pumping stations contributed to 70% of the total BPA observed in this study. For the derived pore water concentration of plasticizers and BPA, the ecotoxicological risk has been found to be higher in ARS over CRS. However, sediment concentrations in all the sites of ARS and CRS were much below the recommended serious risk concentration for human (SRChuman) and serious risk concentration for ecotoxicological (SRCeco).

  • Distribution of metal(loid)s in particle size fraction in urban soil and street dust: influence of population density 2020-01-18


    Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils, and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high, medium and low population density and a natural area were selected and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000–850, 850–180, 180–106, 106–50, 50–20, 20–10, 10–2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined, and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, and Cr was highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human-induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.