Objective To explore the distribution of water with high level arsenic and prevalence of arsenism along Huai'he River and the surrounding area of Hong'ze lake in Huai'an of Jiangsu. Methods Wate rsamples were collected and tested in 2008 from 18 villages of 6 towns according to history data in 3 counties like Xuyi,Jinhu and Hongze. Samples having arsenic level higher than 0.05 mg/L were investigated by epidemiological method and the patients were diagnosed by Standard of Diagnosis for Endemic Arsenism. Results All 5199 water samples were determined,and 260 water samples were exceeding the national drinking water quality level (0.05 mg/L) in 3 counties,the rates of exceeding diagnosis were 5.6%(247/4454),0.7%(4/597),6.0%(9/148) respectively. Total detected rate of endemic arsenic disease was 5.94%(128/2155). The detected rates of age group of 0 ～ ,20 ～,30 ～ ,40 ～ ,50 ～ ,60 ～ ,70 ～ ,80 ～ were 2.86%(1/35),2.11%(2/95),1.26%(3/239),3.10%(16/516),5.53% (32/579),10.07%(41/407),11.84%(27/228),10.71%(6/56) respectively. The detected rate of male (9.10%,78/857) was higher than that of female(3.85%,50/1298,χ~2 = 25.46,P < 0.01). Conclusions Huai'he River and the surrounding areas of Hong'ze lake like Xuyi,Jinhu and Hongze are identified existing endemic arsenic disease area. The prevention of arsenism should be strengthened in these areas.

OBJECTIVETo investigate the effects of arsenic trioxide (As(2)O(3)) on the apoptosis and P-glyco-protein (P-gp) expression of multidrug-resistant human leukemia K562/ADM cells, and the combined effects of As(2)O(3) with conventional chemotherapeutic agents.

METHODSMultidrug-resistant human leukemia cell line K562/ADM that overexpresses mdr-1 gene was used as the target cells. The cell proliferating activity was assessed with a MTT assay. Cell morphology was examined by light microscopy, confocal microscopy and electron-microscopy. P-gp expression, cell-cycle status were determined by flow cytometry.

RESULTSK562/ADM cells were highly resistant to adriamycin, and cross-resistant to daunorubicin and etoposide. As(2)O(3) at concentrations of 0.5 to 20 micromol/L inhibited the proliferation of K562/ADM cells, and K562/ADM cells were more sensitive to As(2)O(3) than their parent K562 cells did. As(2)O(3) induced marked apoptosis of K562/ADM cells showed by typical apoptotic morphological changes and the appearance of high sub-G(1) cell population. As(2)O(3) significantly inhibited the P-gp expression in K562/ADM cells, and exerted a synergistic effect on the enhancement of the cell sensitivity to adriamycin, daunorubicin and etoposide.

CONCLUSIONAs(2)O(3) induces growth-inhibition and apoptosis of multidrug-resistant K562/ADM cells, and augments synergistically the sensitivity of the cells to conventional chemotherapeutic agents via down-regulation of P-gp expression.

ATP-Binding Cassette, Sub-Family B, Member 1 ; biosynthesis ; drug effects ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Daunorubicin ; pharmacology ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Drug Synergism ; Etoposide ; pharmacology ; Humans ; K562 Cells ; Oxides ; pharmacology

OBJECTIVETo explore the effect of small interfering RNA(siRNA) on silence of mdr1 gene and reversal of apoptosis resistance in multidrug-resistant (MDR) human leukemia K562/ADM cell.

METHODSHuman MDR leukemia cell line K562/ADM was used as the target cells. Two siRNAs (mdr1 siRNA-1 and mdr1 siRNA-2) targeted mdr1 gene were chemically synthesized and transfected into K562/ADM cells with liposome. Expression of mdr1 mRNA was determined by real-time PCR, P-glycoprotein (P-gp) expression and caspase-3 activity were measured with flow cytometry (FCM), and the cell apoptosis was observed by optical and electronic microscopy for morphology and Annexin V/PI staining.

RESULTSThe mdr1 siRNA-1 and mdr1 siRNA-2 could markedly down-regulate the expression of mdr1 gene in K562/ADM cells, the expression of mdr1 mRNA decreased by 91.2% and 82.0% , and the P-gp by 74.1% and 84.4%, respectively. The caspase-3 activity was markedly enhanced, and the active caspase-3 in K562/ADM cells increased by about 40% compared to liposome alone and non-silencing controls. the sensitivity of K562/ADM cells to adriamycin-induced apoptosis was significantly augmented, the apoptotic rate of the cells treated with siRNA plus adriamycin increased by about 60% compared to adriamycin alone.

CONCLUSIONsiRNAs silence the expression of mdr1/P-gp to overcome the P-gp-mediated apoptosis resistance in drug-resistant K562/ADM cells.

ATP Binding Cassette Transporter, Sub-Family B ; ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Apoptosis ; Caspase 3 ; metabolism ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Humans ; K562 Cells ; RNA Interference ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Transfection