[A specific PCR assay and a nested PCR assay for the screening of ovine pulmonary adenomatosis].

Ovine pulmonary adenomatosis (OPA) is a naturally occurring contagious lung tumor of sheep which was caused by an exogenous retrovirus of sheep, jaagsiekte retrovirus (JSRV). Although no specific circulating antibodies against the virus coud be detected in infected sheep, exogenous JSRV proviral DNA sequences (exJSRV) and JSRV RNA transcripts could be detected in lung tumors, lymphoreticular system and peripheral blood mononuclear cells (PBMC) from sheep affected by OPA. The sheep genome carried 15 to 20 copies of endogenous retrovirus loci (enJSRV) that were similar to JSRV in structural genes but the divergene in U3. Therefore, primers specific for the U3 sequences of exJSRV were designed for the specific PCR and nested PCR (n-PCR). Sensitivity between specific PCR assay and n-PCR assay was compared by using serial dilutions of positive plasmid pJSRV-LTR in a background of 700ng sheep genome DNA. Sensitivity of n-PCR was ten-fold higher than specific PCR. The n-PCR was only available in blood test for detection of JSRV infected sheep and might be useful in epidemiological studies and disease control of OPA.

[Expression and activation of MAPK pathway signaling molecules in human breast cancer cell lines].

AIM: To detect the expression and status of extracellular regulatory kinase 1 and 2 (ERK1/2) and its upstream kinase MEK1/2 proteins in four breast cancer cell lines MCF-7, Bcap-37, SK-BR-3 and T47D and study the effects of cyclophosphamide and epirubicin on the growth of the cell lines and on the expression and status of the signaling molecules. METHODS: Western blot was used to examine the expression and status of MEK1/2 and ERK1/2 proteins in these cells and the effects of these two drugs on them. The effects of the two drugs on the proliferation of these breast cancer cell lines were detected by MTT colorimetry. RESULTS: The levels of expression and phosphorylation of MEK1/2 and ERK1/2 proteins in four breast cancer cell lines increased notably as compared with those in MCF-10 cells. Both drugs could inhibit the proliferation of breast cancer cells. And the levels of expression and phosphorylation of MEK1/2 and ERK1/2 proteins in breast cancer cell lines treated with the drugs were markedly lower than those in untreated breast cancer cells. CONCLUSION: Overexpression and phosphorylation of MEK and ERK may play an important role in the generation and development of human breast cancer. The inhibitory effect of cyclophosphamide and epirubicin on proliferation of the breast cancer cells may be by means of inhibiting expression and phosphorylation of MEK and ERK.