Objective To investigate the role of hMSH2 in the pathogenesis of sporadic insulinomas and to determine whether the expression of hMSH2 could be used to differentiate benign sporadic insulinomas from malignant ones. Methods Fifty-five sporadic insulinomas (40 benign and 15 malignant tumors) resected from 50 patients were obtained. Expression of hMSH2 was detected by immunohistochemistry staining. DNA was obtained from micradissected tissue. Loss of heterozygnsity (LOH) of hMSH2 gene was detected by PCR-LOH. 6 microsatellite markers were selected on 3 chromosomes, and microsatellite instability (MSI) status of tumor tissue were detected by PCR. The findings were analyzed in relation to the clinicopathological characteristics. Results Down-regulation of hMSH2 expression was found in 13% of 55 sporadic insulinomas. LOH of the hMSH2 gene was not present in 55 insulinomas. High frequency MSI (MSI-H, MSI occurred in at least 2 out of 6 sites) was present in 36% (20/55) of all the insulinomas. Down-regulation of hMSH2 expression was found in 33% of the 15 malignant tumors, while it was 5% in benign tumors (P < 0. 05). Conclusions Down-regulation of mismatch repair gene hMSH2 may be correlated with the degree of tumor malignancy. The expression of hMSH2 could be used as a potential marker for distinguishing benign insulinoma from malignant ones.

OBJECTIVETo explore the effect of microRNA (miRNA)-mediated p65 gene knockdown on the proliferation and apoptosis of human breast cancer MDA-MB-231 cells.

METHODSp65-targeted miRNA plasmid was constructed and transfected into MDA-MB-231 cells via lipofectamine(TM)2000. The expression of p65 gene in the transfected cells at the mRNA and protein levels were detected by RT-PCR and Western blotting, respectively. The cell proliferation and apoptosis were measured by MTT assay and flow cytometry (FCM), respectively. The expressions of apoptosis-related proteins were detected by Western blotting in the transfected cells.

RESULTSCompared with the negative control group, the expressions of p65 mRNA and protein in p65miRNA-trasnfected cells were significantly down-regulated (P<0.05). MTT assay showed significantly lowered viability of MDA-MB-231 cells after the transfection (P<0.05). FCM showed an increased cell apoptosis rate in p65miRNA group compared with that in the negative control group (P<0.05). Caspase-3 and PARP were both cleaved into their active forms and the expression of these active forms was increased in p65miRNA group.

CONCLUSIONThe miRNA targeting p65 gene can inhibit the proliferation and induce apoptosis of breast cancer cells, and p65 gene might become a new target in gene therapy for human breast cancer.

Apoptosis ; genetics ; Breast Neoplasms ; genetics ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Female ; Gene Knockdown Techniques ; Gene Silencing ; Humans ; MicroRNAs ; genetics ; RNA, Messenger ; genetics ; metabolism ; Transcription Factor RelA ; genetics ; metabolism ; Transfection

Humans ; Receptors, Chimeric Antigen ; Hematopoietic Stem Cell Transplantation ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; Immunotherapy, Adoptive ; Antigens, CD19