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

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

    Abstract

    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.

  • Soil–plant system and potential human health risk of Chinese cabbage and oregano growing in soils from Mn- and Fe-abandoned mines: microcosm assay 2020-01-17

    Abstract

    In Portugal, many abandoned mines are often close to agricultural areas and might be used for plant food cultivation. Soils in the vicinity of two Mn- and Fe-abandoned mines (Ferragudo and Rosalgar, SW of Portugal) were collected to cultivate two different food species (Brassica rapa subsp. pekinensis (Lour.) Hanelt and Origanum vulgare L.). Chemical characterization of the soil–plant system and potential risk of adverse effects for human health posed by plants associated with soil contamination, based on the estimation of hazard quotient (HQ), were assessed in a microcosm assay under greenhouse conditions. In both soils, the average total concentrations of Fe and Mn were above the normal values for soils in the region and their concentration in shoots of both species was very high. Brassica rapa subsp. pekinensis grew better in Ferragudo than in Rosalgar soils, and it behaved as an excluder of Cu, Mn, Fe, S and Zn in both soils. The HQ for Cu, Fe, Mn and Zn in the studied species grown on both soils was lower than unit indicating that its consumption is safe. The high Mn tolerance found in both species might be due in part to the high contents of Fe in the soil available fraction that might contribute to an antagonism effect in the uptake and translocation of Mn. The obtained results emphasize the need of further studies with different food crops before cultivation in the studied soils to assess health risks associated with high metal intake.

  • Concentration, fractionation, and ecological risk assessment of heavy metals and phosphorus in surface sediments from lakes in N. Greece 2020-01-13

    Abstract

    The presence of phosphorus (P) and heavy metals (HMs) in surface sediments originating from lakes Volvi, Kerkini, and Doirani (N. Greece), as well as their fractionation patterns, were investigated. No statistically significant differences in total P content were observed among the studied lakes, but notable differences were observed among sampling periods. HM contents in all lakes presented a consistent trend, i.e., Mn > Cr > Zn > Pb > Ni > Cu > Cd, while the highest concentrations were recorded in Lake Kerkini. Most of the HMs exceeded probable effect level value indicating a probable biological effect, while Ni in many cases even exceeded threshold effects level, suggesting severe toxic effects. P was dominantly bound to metal oxides, while a significant shift toward the labile fractions was observed during the spring period. The sum of potentially bioavailable HM fractions followed a downward trend of Mn > Cr > Pb > Zn > Cu > Ni > Cd for most lakes. The geoaccumulation index Igeo values of Cr, Cu, Mn, Ni, and Zn in all lakes characterized the sediments as “unpolluted,” while many sediments in lakes Volvi and Kerkini were characterized as “moderately to heavily polluted” with regard to Cd. The descending order of potential ecological risk \(E_{\text{r}}^{i}\) was Cd > Pb > Cu > Ni > Cr > Zn > Mn for all the studied lakes. Ni and Cr presented the highest toxic risk index values in all lake sediments. Finally, the role of mineralogical divergences among lake sediments on the contamination degree was signified.