ABSTRACT
Background and purpose:The effects of triiodothyronine(T3)on breast cancer remain unclear.The aim of this study was to investigate the expression and correlation of estrogen receptor-?(ER-?)and thyroid hormone receptor-?(TR-?)in breast cancer cell lines,and to determine the changes of relevant receptors expression and its possible mechanism due to T3 treatment.Methods:Real-Time PCR was used to analyze the expressions of ER-? and TR-? at mRNA level in seven breast cancer cell lines.The expression level of retinoid X receptor-?(RXR-?)and these two receptors after T3 treatment were determined as well.The gene profile was further determined in SK-BR-3 cells treated with T3.Results:The expressions of ER-? and TR-? were quite low in SK-BR-3,MDA-MB-231 and MDA-MB-435 cells,but high in MCF7,BT20,BT474 and T47D cells.ER-?,TR-? and RXR-? were upregulated due to T3 treatment in ER-?(-)cells,but not in ER-?(+)cells.In SK-BR-3 cells,T3 treatment led to up-regulation of E2F1,TGF-?1R,TGF-?2R and hTERT,but down-regulation of TGF-?1 and p21.Conclusions:The expressions of ER-? and TR-? are correlated in breast cancer cells;the effect of T3 treatment on hormone receptors is associated with endogenous ER-? level.
ABSTRACT
Background and purpose:Overexpression of human telomerase reverse transcriptase(hTERT)plays a critical role in the process of immortalization of tumor cells.This study aims to investigate siRNA's effects on endogenous hTERT mRNA level and growth of breast cancer cells by targeting hTERT with its specific siRNA.The ultimate goal was to further elaborate the possible mechanism of immortalization in breast cancer cells.Methods:Real-Time RT-PCR was used to determine the hTERT transcripts in various breast cancer cells.hTERT siRNA was transfected into MCF7 cells with lipofectamine 2000.Cell growth was illustrated by growth curve,and cells apoptosis percentage was measured with Flow Cytometry(FACS).The relative expression levels of immortalization-related genes were evaluated with Real-Time RT-PCR.Results:Overexpressions of hTERT were demonstrated in all tested breast cancer cell lines.The inhibitory effects of hTERT siRNA were shown on both hTERT mRNA levels and cell growth from day 4 post transfection.Apoptosis was induced by hTERT siRNA as well.Certain immortalization-related genes were reduced by more than 50%,such as RAC1,PCYT2,FDFT1 and ATP5G2.Conclusions:hTERT siRNA specifically inhibited hTERT at mRNA level as well as cell growth.The apoptosis and downregulation of immortalization-related genes due to hTERT siRNA was demonstrated.
ABSTRACT
Objective To investigate the curative effects of curcumin(CUR)or dexamethasone (DXM)on ischemia-reperfusion injury(IRI)of rat lung grafts.Methods Male SD rats were randomly divided 4 groups:CUR group(CUR was administered intraperitoneally to both donors and recipients at 3 h prior to operation);DXM group(DXM was administered intraperitoneally at 30 min prior to operation);vehicle group(Animals were injected with the DMSO to both donors and recipients at 3 h prior to operation);sham group(Time-matched control animals underwent the same surgery,except that no graft was implanted).Six animals were sacrificed at different reperfusion periods of 2 h and 24 h,respectively.Oxygenation indexes(PO_2/FiO_2),lung injury scores,wet/dry ratio(W/D)and myeloperoxidase(MPO)activity in the transplanted lung were measured.Malondialdehyde(MDA), total anti-oxidative capacity(TAOC),tumor necrosis factor(TNF)-?and interleukin(IL)-6 in the transplanted lung and serum were determined.Results The levels of LPV PO_2/FiO_2 were significant- ly higher in the CUR and DXM groups than in the vehicle groups both 2 and 24 h after reperfusion,re- spectively(P
ABSTRACT
Background and purpose:Most breast cancer cell lines were derived from malignant pleural fluid or other tissues that metastasized from breast carcinoma.Breast carcinogenesis is under represented due to the significant distinction of biological characteristics between cancer cell lines and primary breast cancers.Few primary breast tumors spontaneously developed into immortal cell lines.Overexpression of human telomerase reverse transcriptase(hTERT) in normal epithelial cells led to immortalization.We aimed to establish immortalized cultures derived from primary breast cancer by introducing hTERT and determine the gene profile of hTERT-transfected cultures.Methods:hTERT was introduced into breast tumor cultures with a puromycin-resistant retroviral construct,pBABE-hTERT-puro.Real-Time RT-PCR was used to analyze the expression level of hTERT after transfection.The upregulated gene profile was determined with microarray techniques.Results:hTERT was stably over expressed,at least 1 400-fold in hTERT-transfected cells compared to pBABE-puro transfected cultures.These ectopic over-expressions led to immortalization of transfected cultures,which could undergo at least 40-50 passages.Microarray analysis further confirmed the over-expression of hTERT in transfected cultures and demonstrated that 22 genes were up-regulated due to over-expression of hTERT.No down-regulated genes were observed cross all cultures.Conclusions:Over-expression of hTERT led to immortalization of breast tumor primary cultures and up-regulated certain genes.