Epb41l3 suppresses esophageal squamous cell carcinoma invasion and inhibits MMP2 and MMP9 expression.

EPB41L3 may play a role as a metastasis suppressor by supporting regular arrangements of actin stress fibres and alleviating the increase in cell motility associated with enhanced metastatic potential. Downregulation of epb41l3 has been observed in many cancers, but the role of this gene in esophageal squamous cell carcinoma (ESCC) remains unclear. Our study aimed to determine the effect of epb41l3 on ESCC cell migration and invasion. We investigated epb41l3 protein expression in tumour and non-tumour tissues by immunohistochemical staining. Expression in the non-neoplastic human esophageal cell line Het-1a and four ESCC cell lines - Kyse150, Kyse510, Kyse450 and Caes17 - was assessed by quantitative Polymerase Chain Reaction (qPCR) and Western blotting. Furthermore, an EPB41L3 overexpression plasmid and EPB41L3-specific small interfering RNA were used to upregulate EPB41L3 expression in Kyse150 cells and to downregulate EPB41L3 expression in Kyse450 cells, respectively. Cell migration and invasion were evaluated by wound healing and transwell assays, respectively. The expression levels of p-AKT, matrix metalloproteinase (MMP)2 and MMP9 were evaluated. Expression of epb41l3 was significantly lower in tumour tissues than in non-tumour tissues and in ESCC cell lines compared with the Het-1a cell line. Kyse450 and Caes17 cells exhibited higher expression of epb41l3 than Kyse150 and Kyse510 cells. Overexpressing epb41l3 decreased Kyse150 cell migration and invasion, whereas EPB41L3-specific small interfering RNA silencing increased these functions in Kyse450 cells. Furthermore, overexpressing epb41l3 led to downregulation of MMP2 and MMP9 in Kyse150 and Kyse510 cells. Our findings reveal that EPB41L3 suppresses tumour cell invasion and inhibits MMP2 and MMP9 expression in ESCC cells.

Tai Chi on bone mineral density of postmenopausal osteoporosis: A protocol for systematic review and meta-analysis.

BACKGROUND: Osteoporosis is a clinically common metabolic disease, especially in postmenopausal women. Tai Chi might be beneficial in osteoporosis patients. This study will be performed to examine the effects of Tai Chi on bone mineral density of postmenopausal osteoporosis. METHODS: We will search the electronical databases and hand-searching journals or reference lists. The study screening and data extraction will be carried out by 2 investigators independently. The primary outcome is bone mineral density (lumbar spine, Ward's triangle, trochanter, proximal femur, femoral neck, or total hip). Secondary outcomes are pain score, alkaline phosphatase, osteocalcin, and adverse effects. Review Manager V.5.3 software will be used to compute the data. RESULTS: The results of the study will provide a reliable evidence to assess the effects of Tai Chi on bone mineral density of postmenopausal osteoporosis. CONCLUSION: The conclusion of our systematic review will answer whether Tai Chi is an effective intervention to improve bone mineral density of postmenopausal osteoporosis.

EPB41L3 is a potential tumor suppressor gene and prognostic indicator in esophageal squamous cell carcinoma.

Although there have been reports about the role of erythrocyte membrane protein band 4.1 like 3 (EPB41L3) in several types of cancer, primarily in non-small-cell lung carcinoma, the molecular function and modulatory mechanisms of EPB41L3 remain unclear. In specific, the functional and clinical significance of EPB41L3 in esophageal squamous cell carcinoma (ESCC) has not been explored to date. In the present study, reduced EPB41L3 expression was demonstrated in ESCC cell lines and tissues, which was due to its high methylation rate. Ectopic expression of EPB41L3 in ESCC cells inhibited cell proliferation in vivo and in vitro. In addition, EPB41L3 overexpression induced apoptosis and G2/M cell cycle arrest by activating Caspase-3/8/9 and Cyclin-dependent kinase 1/Cyclin B1 signaling, respectively. Notably, patients with higher EPB41L3 expression had markedly higher overall survival rates compared with patients with lower EPB41L3 expression. In summary, the present results suggest that EPB41L3 may be a tumor suppressor gene in ESCC development, representing a potential therapeutic target and a prognostic indicator for ESCC.

miR-206 enhances nasopharyngeal carcinoma radiosensitivity by targeting IGF1.

Radioresistance remains a major problem in nasopharyngeal carcinoma (NPC) treatment. However, the underlying molecular mechanisms of NPC radioresistance remain poorly understood. The present study aimed to investigate the potential role and mechanism of miR-206 in NPC radioresistance. We observed that miR-206 was down-regulated in radioresistant NPC cells. Furthermore, restoration of miR-206 in CNE2-IR cells suppressed enhanced radiosensitivity of NPC cells. In contrast, inhibition of miR-206 in CNE2 cells reduced the radiosensitivity. We also found that miR-206 directly targeted IGF1 and inhibited the PI3K/AKT pathway. Our data demonstrate that miR-206 sensitizes NPC cell to irradiation by targeting IGF1, highlighting the therapeutic potential of miR-206 in NPC radiosensitization.

MiR-15a suppresses hepatocarcinoma cell migration and invasion by directly targeting cMyb.

PURPOSE: This study aimed to determine the function of miR-15a in HCC, and identify cMyb as a target of miR-15a. METHODS: RNA expression was evaluated by quantitative real-time PCR (qRT-PCR). The effects of miR-15a or cMyb on HCC cells were evaluated by transwell migration assay and western blot analysis. CMyb, the predicted target, has been frequently verified by luciferase assay. RESULTS: MiR-15a was markedly downregulated in sphere culture HCC cells by qRT-PCR. CMyb was predicted to be a potential target of miR-15a using bioinformatics analysis. This prediction has been frequently verified by luciferase assay and western blot. A positive correlation between cMyb and the migration ability of HCC cells was demonstrated by transwell assays. MiR-15a mimic suppressed cMyb expression to weaken HCC cell migration ability. On the other hand, miR-15a inhibitor upregulated cMyb and induced HCC cell migration. CONCLUSION: MiR-15a could suppress HCC progression through the repression of cMyb, making miR-15a a potential therapeutic target.

[The biological behavior of hepatocarcinoma stem cells in rats].

OBJECTIVES: To study the biological behavior of hepatocarcinoma stem cells in rats. METHODS: Primary liver carcinomas were induced in rats using diethylnitrosamine. Tumor cells from 8 rats were separated according to rats oval cell (OVC) markers CD34, c-Kit, Thy-1, AFP, CK7, CK8, CK14, CK18, CK19 and GGT and then they were separately injected into the livers of nude mice. The tumors grown from the different subpopulation of OVC markers in the nude mice livers (10 OVC markers negative or positive cells) were weighted 1 month after the inoculations. The hepatocarcinoma cell subpopulations with higher ability in causing tumor growths were further studied in vitro. The cell cycles and DNA content of those subpopulation cells were investigated using flow cytometry. RESULTS: (1) Subpopulation cells with CK7(-), Thy-1(+) and AFP(+) markers had a higher ability in causing tumors in nude mice; (2) Subpopulation cells, exhibiting characters of TSC, had a low growth rate in vitro. CONCLUSIONS: (1) Different subpopulations of hepatocarcinoma cells had different abilities in causing tumors in rats. Some subpopulation cells, such as CK7(-), Thy-1(+) and AFP(+) cells, have characteristics of tumor stem cells. (2) The hepatocarcinoma stem cells may have a low growth rate in vitro.

[Expression of DNA transcription- and repair-related genes in cisplatin-resistant human ovarian carcinoma cell line COC1/DDP].

OBJECTIVE: To study the molecular mechanism underlying cisplatin resistance in ovarian carcinoma by detecting the expressions of DNA transcription- and repair-related genes in cisplatin-resistant human ovarian carcinoma COC1 cell line. METHODS: The differential expression of DNA transcription- and repair-related genes between the parental COC1 and cisplatin-resistant COC1/DDP cell line was determined using cDNA microarray. RESULTS AND CONCLUSION: Compared with COC1 cells, 143 genes in COC1/DDP cells showed significant differential expression, among which 20 were DNA transcription- and repair-related genes including 13 significantly up-regulated genes and 7 down-regulated ones. Abnormality of DNA transcription and repair might be involved in the development of cisplatin resistance in COC1/DDP cells.

X-ray induced L02 cells damage rescued by new anti-oxidant NADH.

AIM: To explore molecular mechanism of nicotinamide adenine dinucleotide (NADH) antagonization against X-ray induced L02 cells damage. METHODS: L02 liver cells were cultured in RPMI 1640, exposed to X-ray irradiation and continued to culture in the presence or absence of NADH. Cellular viability was analyzed by routine MTT methods. The percent age of apoptotic cells and positive expressions of p53, bax and bcl-2, fas, fasL proteins were determined by FCM. Level of intracellular ROS was determined by confocal microscope scanning. Morphological change was detected by scanning electron micrograph. RESULTS: The viability of L02 cells was decreased with increasing dose of X-ray irradiation. NADH could not only eliminate the apoptosis induced by X-ray irradiation, but also up-regulate expression of bcl-2 protein and down-regulate expression of p53, bax, fas and fasL proteins (P<0.05). At the same time, NADH could reduce level of intracellular ROS in radiated L02 cells. CONCLUSION: NADH has marked anti-radiation effect, its mechanism may be associated with up-regulation of bcl-2 expression and down-regulation of p53, bax fas and fasL expression, as well as decline of intracellular ROS. However, further investigation of its mechanism is worthwhile.

Protective effect of coenzyme I on mouse hematopoietic system against radiation.

OBJECTIVE: To study the protective effect of NADH on the hematopoietic system of mice against radiation. METHODS: Sixty mice were randomized into 3 groups (20/group), Group I serving as normal control group. Three days before exposure to single-dose (6.0 Gy) whole body 60Co gamma-ray irradiation in the other 2 groups, the mice in Group II received injections with 0.9% NaCl and those in Group III with intraperitoneal NADH (10 mg/kg, twice daily). The peripheral white blood cells count was carried out in the blood samples from the mouse tail vein at different time after the exposure, and the bone marrow smears were prepared with routine staining to examine the number of the granulocytes and determine their mitotic index 24 h after radiation. DNA fragmentation in mouse bone marrow cells was detected by DNA electrophoresis 24 and 48 h after irradiation. RESULTS: The white blood cell count was significantly higher in mice with coenzyme I treatment before exposure to the irradiation. NADH also increased the number of the granulocytes and their mitotic index without inhibiting DNA fragmentation in the bone marrow cells as observed 24 and 48 h after the irradiation. CONCLUSION: NADH can markedly prevent the damages to the hematopoietic system in mice exposed to irradiation, but the mechanism does not involve the inhibition of bone marrow cell apoptosis.

[Effect of NADH against liver cell line L02 apoptosis induced by UVB irradiation].

OBJECTIVE: To study the molecular mechanism behind the effect of reduced nicotinamide adenine dinucleotide (NADH) against apoptosis of liver cell line L02 induced by ultraviolet B (UVB) exposure. METHODS: L02 liver cells were exposed to UVB irradiation (200 J/m(2)) followed by a 24-hour culture in the presence or absence of NADH (400 microgram/ml). The degraded fragments of DNA in the cells were observed by agarose electrophoresis, the cell apoptosis rate determined by Annexin/V PI staining and p53, Bax and Bcl-2 proteins expression detected by flow cytometry. RESULT: NADH not only inhibited the apoptosis induced by UVB irradiation, but also up-regulated the expression of Bcl-2 protein and down-regulated expressions of p53 and Bax proteins (P<0.01). Repair of DNA strand damage was observed in L02 cells during the incubation time after irradiation. CONCLUSION: NADH significantly inhibits apoptosis induced by UVB irradiation possibly by the mechanism of up-regulating Bcl-2 expression and down-regulating p53 and Bax expressions.

[Morphological observation on NK/LAK cell-mediated lysis of human oral carcinoma cells].

OBJECTIVE: To understand the relation between cytotoxic activity of immunologic effector cells and multidrug resistance of the tumor cells. METHODS: Continuous observation of the morphological changes and MTT colorimetry were employed to evaluate the cytotoxic activity of lymphokine-activated killer (LAK) cells and natural killer (NK) cells against multidrug-resistant (MDR) human oral carcinoma cell line-KBV200 (before and after reversal of MDR) and parental drug-sensitive cell line KB. The morphologic changes of LAK cells and the 3 target cell lines were observed continuously under inverted microscope 3 h after co-culture of LAK cells with one of three target cell lines respectively. The lysis rates of three tumor cell lines in response to co-culture with LAK or NK cells were determined using MTT colorimetry. RESULTS: In comparison with the parental drug-sensitive cell line KB, both KBV200 and its reserved cell line by verapamil (KBVV) showed earlier adherence and greater number of cells lysed by LAK. In MTT colorimetry assay, the cytotoxicity of both LAK and NK cells against the 3 cell lines was associated with the effector-to-target (E/T) cell ratio; the lysis rates of KBV200 and reversed KBV200 cells by verapamil in response to LAK and NK cells were higher than that of KB cells (P<0.05), but KBV200 and KBVV did not significantly differ (P>0.05). At the same E/T ratio, LAK cells possessed stronger cytotoxicity than NK cells against all the tumor cell lines (P<0.05). CONCLUSIONS: Immunologic effector cells possess strong cytotoxic activity against multidrug-resistant cell line KBV200. Modulation of MDR does not decrease the cytotoxic activity of the immunologic effector cells. The results of this study suggest that adoptive cell immunotherapy with immunologic effector cells may be of value in controlling the progress of MDR tumors.

[Effects of anti-HPV16 E6-ribozyme on invasiveness of cervical carcinoma cell line CaSKi and vascular endothelial growth factor expression].

OBJECTIVE: To investigate the changes in the invasiveness of cervical cancer cell line CaSKi and the expression of vascular endothelial growth factor (VEGF) in response to treatment with anti-HPV16 E6-ribozyme, which plays a important role in the malignant phenotype and conversion of cervical cancer cells. METHODS: By means of lipofectin transfection, anti- HPV16 E6-ribozyme and empty eukaryotic expression plasmids were respectively transfected into CaSKi cell line (designated as CaSKi-R and CaSKi-P respectively). CaSKi, CaSKi-R and CaSKi-P cells were observed for their cell growth curves, clone forming ability on soft agar and tumorigenicity in nude mice. One-step reverse transcriptional PCR (RT-PCR) was employed to examine the expression of VEGF. RESULTS: No significant differences were found in the growth rate, clone forming ability and tumorigenicity between CaSKi and CaSKi-P cells. In contrast, CaSKi-R exhibited obviously decreased growth rate, clone forming ability and tumorigenicity (P<0.05). RT-PCR analysis showed that the expression levels of VEGF mRNA in CaSKi-R cells were lower than those in CaSKi-P and CaSKi cells. CONCLUSION: Anti-HPV16 E6-ribozyme may reduce the proliferative ability and invasiveness of cervical cancer cell line CaSKi, possibly through decreasing VEGF expression in CaSKi cells.

Effects of anti-HPV16 E6-ribozyme on the proliferation and apoptosis of human cervical cancer cell line CaSKi.

OBJECTIVE: To study the characterization of anti-HPV16E6-ribozyme transfected into cultured human cervical cancer cell line, and to investigate the effect of ribozyme on the proliferation and apoptosis of the cells. METHODS: By way of lipofectin transfection, anti-HPV16E6-ribozyme, a ribozyme designed to specifically cleave the HPV16E6 gene, and empty vector expression plasmids were respectively transfected into CaSKi cells which were subsequently designated as CaSKi-R and CaSKi-P accordingly. The expression of ribozyme in the transfected cells was observed by RNA dot blot analysis, and E6 mRNA expression was detected by Northern blotting in the 3 kinds of cells whose growth curves and clone-forming ability on soft agar were studied, with their tumorgenicity observed by percutaneous inoculation of the cells in nude mice. Flow cytometry was employed to assess the apoptosis rates and the expression of the genes including c-myc, bcl-2, p53, and fas etc. RESULTS: Stable expression of anti-HPV16E6-ribozyme was observed in CaSKi-R cells that had less E6 mRNA expression than CaSKi had as shown by Northern blotting. When compared with those of CaSKi cells, the growth rate and clone-forming ability on soft agar of CaSKi-R were reduced, while those of CaSKi-P evinced no significant changes. The tumorgenicity of CaSKi-R in nude mice was also comparatively decreased, with markedly elevated apoptosis rate. Anti-HPV16E6-ribozyme reduced the expressions of E6, c-myc, bcl-2, PCNA and C-erbB2 genes but increased p53 expression in CaSKi-R cells, which, however, did not happen in CaSKi-P cells. The expression of Fas underwent no significant changes in response to the transfection. CONCLUSION: Anti-HPVE6-ribozyme inhibits proliferation and induces apoptosis in CaSKi cells, possibly due to the decrease of E6 gene expression that triggers a series of changes in the gene expressions of the cells.

[In vitro regulation of HLA and B7 expression in multidrug-resistant breast cancer cells].

OBJECTIVE: To study the modulation of the expressions of human leucocyte antigen (HLA) and co-stimulatory molecules B7 (CD80, CD86) in multidrug-resistant (MDR) breast cancer cells. METHODS: The MDR phenotype MCF-7/ADR cells were treated with recombinant human interferon (IFN)-alpha2b (rhIFN-alpha2b) at different doses for varied length of time, and the expressions of HLA and B7 were determined by flow cytometry (FCM) and compared with those of non-treated cells. Statistical analysis was performed using SPSS10.0 software. RESULTS: At the doses smaller than 1x10(3) IU/ml, rhIFN-alpha2b did not exhibit significant inhibition on MCF-7/ADR cell growth, but HLA and B7 expressions were enhanced in a dose- and time-dependent fashion and significant up-regulation occurred 24 h after 400 IU/ml rhIFN-alpha2b treatment. Treatment with rhIFN-alpha2b at the doses of 100, 400, 800 IU/ml respectively for 24 h produced significant increases in the positive cell ratios for HLA class I expression (P<0.05), HLA-DR expression (P<0.005) and B7-2 expression (P<0.05), while changes in B7-1 expression was not obvious (P>0.05). The mean relative linear fluorescence intensity (RLFI) of HLA class I was also significantly increased (P<0.001) but alterations in the mean RLFI of HLA-DR and B7 were not significant. CONCLUSIONS: rhIFN-alpha2b within the dose range from 400 to 800 IU/ml can effectively enhance the expression of HLA and B7 molecules, suggesting that it may have the potential to reverse immune tolerance of breast cancer cells. Cytokine treatment may be effective in reversing immune tolerance caused by down-expression of HLA and B7.

[Up-regulation of c-myc expression in MCF-7/Adr human breast cancer cells and its association with resistance against doxorubicin].

OBJECTIVE: To investigate the expression of c-myc in drug-resistant MCF-7/Adr human breast cancer cells and the counteractive effect of c-myc antisense oligonucleotide on their drug-resistance. METHODS: Flow cytometry was performed to examine c-myc expression in multi-drug resistant MCF-7/Adr cell line and its parental cell line MCF-7. The IC50 value of doxorubicin was evaluated by MTT assay. RESULTS: MCF-7/Adr cell line was shown to have a significantly higher expression rate of c-myc than its parent cell line MCF-7 (70.48% vs 46.02%). The IC50 value of doxorubicin was (22.00+/-1.92) micomol/L in MCF-7/Adr cells, which was significantly decreased to (9.60+/-1.04) micromol/L (P<0.05) after coincubation with 4 micromol/L c-myc antisense oligonecleotide. CONCLUSION: c-myc expression is up-regulated in MCF-7/Adr cells as compared with their parent cell line MCF-7. Inhibition of c-myc expression may partially reverse the resistance of MCF-7/Adr against doxorubicin, suggesting that c-myc may be involved in the mechanism of drug-resistance of tumor cells.

[Expression of glucosylceramide synthase mRNA in vincristine-resistant KBV200 cell line in association with multidrug resistance].

OBJECTIVE: To investigate the relationship between the expression of glucosylceramide synthase (GCS) mRNA in vincristine-resistant KBV(200) human cancer cell line and multidrug resistance (MDR) of the cancer cells. METHODS: Reverse transcriptional polymerase chain reaction (RT-PCR) was employed to analyze the differential expression of GCS mRNA between KBV(200) and KB cell lines and the changes in the mRNA expressions of GCS and mdr1 gene in KBV(200) cells after reversion of MDR. The effects of de-phenyl-z-palmaitoylamino-3-morpholine-1-propanol (DL-PPMP) and verapamil in reversing MDR of the cells were evaluated by MTT assay. RESULTS: KBV(200) cells exhibited significantly increased expressions of GCS and mdr1 gene, whereas mdr1 gene failed to be detected in the parental KB cells. DL-PPMP within the concentrations ranging from 5 to 25 micromol/L could inhibit the expression of GCS gene, with the maximum inhibition achieved at 25 micromol/L. Verapamil at the concentration of 10 micromol/L was already sufficient to induce inhibition of GCS expression in KVB(200) cells, which was more manifest with the concentration of 15 micromol/L. DL-PPMP and verapamil were found to inhibit mdr1 gene expression in KBV(200) cells at the mRNA level, and complete inhibition occurred after a 48-hour DL-PPMP treatment at 25 micromol/L. CONCLUSION: The inhibition of GCS and mdr1 gene expressions is positively correlated with the concentrations of DL-PPMP and verapamil, which can reverse MDR by inhibiting synthesis of GCS and mdr1 gene, indicating the positive correlation between the expression of GCS gene and MDR in KBV(200) cells. GCS gene might play an important role in MDR during tumor progression.

[Comparative study of three local ablation methods for transplanted hepatocellular carcinoma in mice].

OBJECTIVE: To observe the effects of three commonly used local ablation methods in the treatment of transplanted hepatocellular carcinoma in mice to provide experimental evidence for treating hepatocellular carcinoma that defies surgical removal. METHODS: Mouse models of hepatocellular carcinoma were established by means of subcutaneous transplantation, and treatment results of the three ablation methods, namely percutaneous ethanol injection therapy (PEIT), percutaneous acetic acid injection therapy (PAIT) and percutaneous local cryosurgery therapy (PLCT), were compared. RESULTS: The tumor inhibition rates of PLCT, PAIT and PEIT were 99.2%, 85.3%, and 72.8%, respectively. The rates for complete necrosis of the tumors were 100% (5/5), 60% (3/5), and 40% (2/5), with the survival time of 88.11+/-5.67, 86.67+/-7.26, and 72.89+/-12.86 days respectively. CONCLUSIONS: All of the three local ablation methods can inhibit the tumor growth to various degrees and prolong the survival time of the tumor-bearing mice. PLCT may yield relatively better result than the other two methods.

Glivec enhances the down-regulated cytotoxicity of adriamycin in acquired tamoxifen-resistant MCF-7 cell line.

OBJECTIVE: To study the alteration of bax, bcl-2, p170 expressing and the second effect on the adriamycin (ADR) induced cytotoxicity in acquired tamoxifen (TAM)-resistant MCF-7 cell line. METHODS: The bax, bcl-2, p170 protein expressions were detected by flow cytometry respectively, as well as the content of intracellular ADR. The in vitro adenosine triphosphate tumor chemosensitivity assay (ATP-TCA) was performed to evaluate the cytotoxicity of ADR, and also the effect of Glivec on the cytotoxicity of ADR. RESULTS: The percentages of bax, bcl-2 expressions in the acquired TAM resistant MCF-7 were down-regulated from 53.17+/-1.45% to 28.70+/-1.41% (P <0.01), 41.53+/-2.17% to 37.87+/-1.86% P >0.05 respectively, the p170 was up-regulated from 27.43+/-2.16% to 32.13+/-1.31% (P <0.05), after a 16-week-treatment with 1 x 10(-7) mol/L TAM. Accordingly, the chemosensitivity and the fluorescence intensity of intracellular ADR declined, both of them can be significantly reversed by 10 microg/ml Glivec. CONCLUSION: The acquired TAM resistant MCF-7 accompanied with a declined ADR cytotoxicity, down-regulation of bcl-2/bax-induced apoptosis and up-regulation of p170-induced drug efflux may had a synergic devotion. Glivec may enhance the cytotoxicity of ADR on the acquired TAM-resistant MCF-7 cell line.

[Diagnosis of hepatocellular carcinoma with bone metastasis using fine needle aspiration biopsy: report of 2 cases].

The clinical presentations and imaging characteristics of hepatocellular carcinoma (HCC) are usually various and complex. This article reported 2 cases of HCC with the initial symptoms being bone metastasis that did not exhibit typical clinical manifestations or distinct feature in liver imaging, without elevated serum alpha-fetoprotein. The diagnoses were certified by fine needle aspiration biopsy, which is recommended for differential diagnosis in cases of complex HCC with bone metastasis, to avoid liver biopsy and surgical bone biopsy.

Effect of coenzyme I on apoptosis of liver cell line L02 induced by ischemia-reperfusion injury.

OBJECTIVE: To study the protective effect of coenzyme I (NADH) on normal liver cell line L02 against ischemia-reperfusion injury. METHODS: Cultured L02 cells was divided into 3 groups, namely ischemia-reperfusion group (I/R), ischemia-reperfusion group with NADH pretreatment (NADH+I/R) and control group. Assisted by flow cytometry (FCM), the apoptosis rate and the expression of apoptosis-related proteins (Bcl-2, p16, p21, p53) were detected in L02 cells in the 3 groups. Apoptotic L02 cells were also observed under transmission electron microscope. RESULTS: I/R significantly inhibited L02 cell proliferation and increased their apoptosis rate up to (31.53+/-8.27)% 12 h after I/R. In the presence of NADH, however, the apoptotic rate of the cells was significantly decreased to (12.61+/-2.34)% (P<0.05). FCM indicated that I/R down-regulated the expression of Bcl-2 and up-regulated the expression of p16, p21 and p53 proteins as compared with control group, but NADH acted to the reverse effect. Typical apoptotic features were observed by transmission electron microscope in the cells 12 h after I/R. CONCLUSION: I/R might induce apoptosis in L02 cells by up-regulating the expression of p16, p21, p53 and down-regulating the expression of Bcl-2, and the protective effect of NADH against I/R-induced apoptosis may lie in the expression regulation of the proteins concerned.