Restoration of secreted frizzled-related protein 1 suppresses growth and increases cisplatin sensitivity in laryngeal carcinoma cells by downregulating NHE1.

It has been documented that secreted frizzled-related protein 1 (SFRP1) is epigenetically silenced in laryngeal carcinoma. However, the function of SFRP1 in laryngeal carcinoma remains elusive. In this study, we performed gain-of-function studies to determine the roles of SFRP1 in laryngeal carcinoma growth, tumorigenesis, and cisplatin resistance. Laryngeal carcinoma cell lines were treated with 5-aza-2'-deoxycytidine (5-aza-dC) and examined for SFRP1 expression. The effects of overexpression of SFRP1 on cell proliferation, colony formation, apoptosis, tumorigenesis, and cisplatin sensitivity were assessed. It was found that 5-aza-dC exposure significantly induced the expression of SFRP1 in both Hep-2 and SNU899 laryngeal carcinoma cells. Ectopic expression of SFRP1 significantly decreased cell proliferation and colony formation in vitro and retarded xenograft tumor growth in vivo. SFRP1-overexpressing Hep-2 cells displayed a higher percentage of apoptosis and enhancement of caspase-3 cleavage, which was coupled with loss of Δψm and increased release of cytochrome c from the mitochondria to the cytosol. Moreover, SFRP1 overexpression sensitized laryngeal carcinoma cells to cisplatin and decreased intracellular pH values. Mechanistically, SFRP1 inhibited the expression of Na+/H+ exchanger 1 (NHE1) and overexpression of NHE1 reversed the suppressive activity of SFRP1 on laryngeal carcinoma cells. In conclusion, we demonstrate that SFRP1 induces mitochondrial apoptosis and increases cisplatin sensitivity in laryngeal carcinoma cells via downregulation of NHE1. Delivery of SFRP1 may offer therapeutic benefits in the treatment of laryngeal carcinoma.

[Detection of human parvovirus B19 nonstructural protein DNA by nested- polymerase chain reaction in pregnant women].

OBJECTIVE: To explore the sensitivity and specificity of the new nested-polymerase chain reaction (nested-PCR) assay in the detection of human parvovirus B19 (HPV B19) nonstructural protein DNA and the applicability of this technique in detecting the gravida infected with parvovirus B19. METHODS: Evaluating the new nested-polymerase chain reaction assay by routine process, and compared with the general nested-PCR in detecting structural protein DNA. Then, the two techniques were used to detect human parvovirus B19 structural protein and nonstructural protein DNA in gravida serum and pregnant tissue of 30 cases. RESULTS: The sensitivity of the new method was 0.005 fg which was similar to the general nested-polymerase chain reaction assay, and the detection results of other viruses and human genome DNA were all negative. The positive rates of structural protein DNA and nonstructural protein DNA in gravida sera were 26.7% and 33.3%, respectively. And the difference was non significant in statistics. At the same time, both of these two positive rates in placenta and villus were 26.7%. CONCLUSIONS: The new nested-polymerase chain reaction assay was a sensitive, specific and convenient method in detecting human parvovirus B19 infection, and the detection of nonstructural protein DNA paves the way for the following study on the disease mechanisms of B19.

[Application of factor analysis in the study of risk factors on human parvovirus B19 infection during pregnancy].

OBJECTIVE: To explore the risk factors of human parvovirus B19 infection in pregnancy and to provide guidelines for its prevention and control strategy. METHODS: Four hundred and eighty-six cases of gravida serum were detected for parvovirus B19 DNA by nested-polymerase chain reaction assay. Factors associated with parvovirus B19 infection in pregnancy were investigated and analyzed, using multiple logistic regression and factor analysis. RESULTS: Multiple logistic regression analysis suggested that there were 16 agents associated with parvovirus B19 infection during pregnancy, which were dominated by 6 potential factors listed as follows: countryside and bad hygienic habit, mental factor, occupational exposure to hospital and environmental condition, health and illness, bad behavior and health education and blood type. CONCLUSION: The prevention strategy of parvovirus B19 infection in pregnancy should include reasonable allocation of public health resources between city and countryside, and to promote health education and occupational health during pregnancy.