A one-step aptasensor for ultrasensitive detection of lung cancer marker homocysteine based on multifunctional carbon nanotubes by square-wave voltammetry.

In this work, a one-step aptasensor for ultrasensitive detection of homocysteine (HCY) is developed based on multifunctional carbon nanotubes, which is magnetic multi-walled carbon nanotubes (Fe3O4@MWCNTs) combined with the aptamer (Apt) for HCY (Fe3O4@MWCNTs-Apt). Fe3O4@MWCNTs-Apt have multiple functions as follows. (1) Apt immobilized could selectively capture all target molecules HCY in the sample; (2) Magnetic Fe3O4 nanoparticles could separate all target molecules HCY captured by Apt from the sample substrate to eliminate the background interference and achieve one-step preparation of the aptasensor; And (3), MWCNTs with good electrical conductivity become a new electrode surface, construct a three-dimensional electrode surface network, make the electron transfer easier and thus then enhance the signal response. Results show that there is a good linear relationship between peak current of square-wave voltammetry (SWV) and HCY concentration in the range of 0.01 µmol/L-1 µmol/L, with a limit of detection (LOD) 0.002 µmol/L. And, selectivity, reproducibility, precision and accuracy are all satisfactory. In addition, it could be applied to the detection of HCY in the plasma of lung cancer patients successfully, suggesting that this one-step aptasensor for HCY has a potential in practical clinical applications.

Expression and Biological Functions of EPC1 in Nasopharyngeal Carcinoma.

BACKGROUND: Comb homolog enhancer 1 (EPC1) gene is one of the important members of epigenetic inhibitor PCG family. It shows carcinogenic potential in a variety of malignant tumors, but the expression and role of EPC1 in nasopharyngeal carcinoma are unclear. The aim of this study was to explore the expression and function of enhancer of polycomb homolog 1 (EPC1) in nasopharyngeal carcinoma (NPC). METHODS: The differential expression of EPC1 in the cancer tissues and cell lines of NPC was examined by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). EPC1 expression, cell proliferation, and apoptosis were detected in NPC cell lines after EPC1 silencing, and the levels of the epithelial-mesenchymal transition (EMT)-related proteins E-cadherin and vimentin were detected in NPC cells after EPC1 silencing. The study was performed at Fujian Provincial Hospital, Fujian, China, from 2018 to 2019. RESULTS: We found that EPC1 was significantly upregulated in the cancer tissues and cell lines of NPC (P<0.001). Furthermore, knockdown of EPC1 inhibited the growth and metastasis of NPC cells. E-cadherin and vimentin were detected in NPC cells after EPC1 was knocked out. It was confirmed that inhibition of EPC1 resulted in increased E-cadherin expression (P<0.001) and decreased vimentin expression (P<0.001), suggesting that inhibition of EPC1 could inhibit the EMT in NPC cells. CONCLUSION: EPC1 expression was upregulated in NPC tissues and cell lines. Knockout of EPC1 effectively inhibited the growth of NPC cells, induced apoptosis, and inhibited invasion and metastasis. Inhibition of EPC1 could inhibit the EMT in NPC cells. All of the above findings support the viewpoint that EPC1 plays a pro-cancer role in NPC.