Mechanism of SPARC-enhanced chemosensitivity of pancreatic cancer cells to gemcitabine / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The aim of this study was to explore the effect of SPARC on the anti-cancer effect of gemcitabine and underlying mechanism in pancreatic cancer.</p><p><b>METHODS</b>After treating with gemcitabine, the proliferation rate of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells was detected by MTT assay. The cell cycle distribution and cell apoptosis in each group were examined by flow cytometry, and the capability of clone formation was tested by adhesion-dependent clone formation assay. The apoptosis-related proteins were analyzed by Western blot.</p><p><b>RESULTS</b>The growth of pancreatic cancer cells was inhibited by gemcitabine in a time-dependent and dose-dependent manner. Its IC50 at 24, 48, and 72-h was (40.1 ± 2.5) µmol/L, (15.0 ± 0.5) µmol/L and (6.6 ± 0.1) µmol/L, respectively. The overexpression of SPARC increased the inhibitory effect of gemcitabine on growth of pancreatic cancer MIA PaCa2/SPARC69 cells, presenting a dose- and time- dependent manner. Its IC50 at 24, 48, 72 h was (24.3 ± 1.5) µmol/L, (7.7 ± 0.3) µmol/L and (4.8 ± 0.2) µmol/L, respectively. The clone formation assay showed that before gemcitabine treatment, the clone numbers of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (2350 ± 125), (2130 ± 120) and (1567 ± 11), respectively. After gemcitabine treatment, the clone numbers of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were ( 1674 ± 79) , (1587 ± 94) and (557 ± 61), respectively. The overexpression of SPARC enhanced the chemosensitivity of MIA PaCa2 cells to gemcitabine chemotherapy. After treating with 10 µmol/L gemcitabine for 48 h, the ratio of G0/G1 cells in MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (56.0 ± 5.5)%, (55.0 ± 4.5)% and (68.0 ± 7.0)%, respectively. The cells arrested at G0/G1 phase were significantly increased in the MIA PaCa2/SPARC69 cells. The apoptosis rates of MIA PaCa2, MIA PaCa2/V and MIA PaCa2/SPARC69 cells were (22.4 ± 2.5)%, (19.9 ± 2.0)% and (37.7 ± 3.9)%, respectively, indicating that overexpression of SPARC enhanced the gemcitabine-induced apoptosis in MIA PaCa2 cells. The Western blot analysis showed that, compared with MIA PaCa2 and MIA PaCa2/V cells, the expression of caspase-2, -8, -9 and cleaved PARP protein was significantly increased, while the expression of Bcl-2 was not changed significantly in the MIA PaCa2/SPARC69 cells.</p><p><b>CONCLUSION</b>SPARC can enhance the chemosensitivity of pancreatic cancer cells to gemcitabine via regulating the expression of apoptosis-related proteins.</p>

Apoptosis in HEp-2 cells infected with Ureaplasma diversum

BACKGROUND: Bacterial pathogens have many strategies for infecting and persisting in host cells. Adhesion, invasion and intracellular life are important features in the biology of mollicutes. The intracellular location ofUreaplasma diversum may trigger disturbances in the host cell. This includes activation or inhibition of pro and anti-apoptotic factors, which facilitate the development of host damage. The aim of the present study was to associate U. diversum infection in HEp-2 cells and apoptosis induction. Cells were infected for 72hs with four U. diversum clinical isolates and an ATCC strain. The U. diversuminvasion was analyzed by Confocal Laser Scanning Microscopy and gentamicin invasion assay. The apoptosis was evaluated using pro-apoptotic and anti-apoptotic gene expression, and FITC Annexin V/Dead Cell Apoptosis Kit. RESULTS: The number of internalized ureaplasma in HEp-2 cells increased significantly throughout the infection. The flow cytometry analysis with fluorochromes to detect membrane depolarization and gene expression for caspase 2, 3 and 9 increased in infected cells after 24 hours. However, after 72 hours a considerable decrease of apoptotic cells was observed. CONCLUSIONS: The data suggests that apoptosis may be initially induced by some isolates in association with HEp-2 cells, but over time, there was no evidence of apoptosis in the presence of ureaplasma and HEp-2 cells. The initial increase and then decrease in apoptosis could be related to bacterial pathogen-associated molecular pattern (PAMPS). Moreover, the isolates of U. diversum presented differences in the studied parameters for apoptosis. It was also observed that the amount of microorganisms was not proportional to the induction of apoptosis in HEp-2 cells.

Influence of recombinant lentiviral vector encoding miR-15a/16-1 in biological features of human nasopharyngeal carcinoma CNE-2Z cells / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the influence of recombinant lentiviral vector encoding miR-15a/16-1 on biological features of human nasopharyngeal carcinoma CNE-2Z cells and underlying mechanisms.</p><p><b>METHODS</b>GFP-positive CNE-2Z cells transfected with recombinant lentiviral vector were selected. The experiment was divided into control group, transfected group, radiotherapy group, transfected-radiotherapy group. Cell proliferation was analyzed by MTT. Apoptosis was detected by flow cytometry. Radiotherapy sensitivity of the cells in control group and transfected group was evaluated by colony forming experiment. The expressions of miR-15a, miR-16-1 and bcl-2 mRNA were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The expression of bcl-2 protein was detected by Western blot. The activation of Caspase-2 and Caspase-3 was evaluated by spectrophotometry.</p><p><b>RESULTS</b>Relative expression quantities of miR-15a and miR-16-1 in infected group were 524.80 ± 40.79 (t = 494.611, P = 0.000) and 466.11 ± 40.96 (t = 386.8, P = 0.000), respectively. The proliferation of the cells in transfected-radiotherapy group was the most obvious, followed by the cells in radiotherapy group and transfected group (F = 424.3, P = 0.000). The apoptosis rates of control group, transfected group, radiotherapy group and transfected-radiotherapy group were (2.2 ± 1.4)%, (9.6 ± 0.8)%, (2.9 ± 1.1)%, and (18.6 ± 0.7)% respectively(F = 158.5, P = 0.000). Clonogenic assay showed that the values of SF2, Do (1.473) and Dq (1.581) in transfected group were lower than those in control group. The relative expression levels of bcl-2 mRNA in transfected group, radiotherapy group, and transfected-radiotherapy group had no significant difference (P > 0.05). Decrease in the expression of bcl-2 protein in transfected-radiotherapy group was most significantly, followed by that in transfected group. The percentages of activated Caspase-2 in control group, radiotherapy group, transfected group and transfected -radiotherapy group were 0.12 ± 0.01, 0.24 ± 0.04, 0.35 ± 0.02, and 0.44 ± 0.04, respectively (F = 115.500, P = 0.000). The percentages of activated Caspase-3 in the groups were 0.13 ± 0.01, 0.27 ± 0.01, 0.43 ± 0.02, and 0.83 ± 0.06, respectively (F = 439.921, P = 0.000).</p><p><b>CONCLUSIONS</b>Recombinant lentiviral vector LV-miR15a/16-1 could improve the expression of miR-15a and miR-16-1 in CNE-2Z cells, inhibit the proliferation of CNE-2Z cells, promote apoptosis and enhance the sensitivity of the cells to radiotherapy probably by inhibiting bcl-2 expression, activating Caspase-2 and Caspase-3.</p>

Berberine inhibits norepinephrine-induced apoptosis in neonatal rat cardiomyocytes via inhibiting ROS-TNF-α-caspase signaling pathway / 中国结合医学杂志

<p><b>OBJECTIVE</b>To determine the effect of berberine (Ber) on norepinephrine (NE)-induced apoptosis in neonatal rat cardiomyocytes.</p><p><b>METHODS</b>The cultured neonatal rat cardiomyocytes were treated with NE in the presence or absence of Ber. The activity of lactate dehydrogenase (LDH) in the culture medium was examined, and apoptosis of cardiomyocytes was assessed by Hoechst 33258, isothiocyanate (FITC)-conjugated annexin-V, and propidine iodide (PI) staining. In addition, the activities of caspases-2 and-3 were measured by a fluorescent assay kit. The level of secreted tumor necrosis factor α (TNF-α) and production of intracellular reactive oxygen species (ROS) were also determined.</p><p><b>RESULTS</b>NE at a concentration of 50 μ mol/L induced an obvious increase in the activity of LDH in the culture medium (P<0.05), which was inhibited by coincubation with 0.5, 1.0, or 2.0 μ mol/L Ber (P<0.05). Ber also significantly attenuated NE-induced apoptosis in a dose-dependent manner (P<0.01). Moreover, Ber at a dose of 2 μ mol/L markedly decreased the ROS and TNF-α productions (P <0.05) and inhibited the activation of caspases-2 and -3 in cardiomyocytes exposed to NE (P<0.05)h.</p><p><b>CONCLUSION</b>The present study suggested that Ber could reduce NE-induced apoptosis in neonatal rat cardiomyocytes through inhibiting the ROS-TNF-α-caspase signaling pathway.</p>

Expression Pattern of Caspase 2 in Korean Gastric Cancers

PURPOSE: Caspase 2, a member of the family of ICE-like proteases, is activated by the Fas pathway and induces apoptosis by triggering the caspase cascade. The purpose of this study was to determine whether the expression pattern of caspase 2 might be associated with gastric cancer development and if so, to determine to which pathologic parameter it is linked. MATENRIALS AND METHODS: For the construction of the gastric cancer tissue microarray, 78 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression pattern of caspase 2 was examined on tissue microarray slides by using immunohistochemistry and was compared with pathologic parameters, including histologic type, depth of invasion, lymph node metastasis, and peritoneal dissemination. RESULTS: Caspase 2 was expressed on superficial and foveolar epithelial cells and lymphocytes in the gastric mucosa, mainly in cytoplasm. We found loss of caspase 2 expression in 41 (52.6%) of the 78 gastric cancer tissues. Statistically, histologic type and other pathologic parameters were not related with loss of caspase 2 expression. CONCLUSION: Our findings provide enough evidence that loss of caspase 2 expression may contribute to the development of Korean gastric cancer and that it might be one of the possible escape mechanisms from apoptosis in gastric cancer.

A Study on Apoptotic Signaling Pathway in HL-60 Cells Induced by Radiation / 대한방사선종양학회지

PURPOSE: The mechanical insights of death of cancer cells by ionizing radiation are not yet clearly defined. Recent evidences have demonstrated that radiation therapy may induce cell death via activation of signaling pathway for apoptosis in target cells. This study is designed whether ionizing radiation may activate the signaling cascades of apoptosis including caspase family cysteine proteases, Bcl2/Bax, cytochrome c and Fas/Fas-L in target cells. MATERIALS AND METHODS: HL-60 cells were irradiated in vitro with 6 MV X-ray at dose ranges from 2 Gy to 32 Gy. The cell viability was tested by MTT assay and the extent of apoptosis was determined using agarose gel electrophoresis. The activities of caspase proteases were measured by proteolytic cleavages of substrates. Western blot analysis was used to monitor PARP, Caspase-3, Cytochrome-c, Bcl-2, Bax, Fas and Fas-L. RESULTS: Ionizing radiation decreases the viability of HL-60 cells in a time and dose dependent manner. Ionizing radiation-induced death in HL-60 cells is an apoptotic death which is revealed as characteristic ladder-pattern fragmentation of genomic DNA over 16 Gy at 4 hours. Ionizing radiation induces the activation of caspase-2, 3, 6, 8 and 9 of HL-60 cells in a time-dependent manner. The activation of caspase-3 protease is also evidenced by the digestion of poly (ADP-ribose) polymerase and procaspase- 3 with 16Gy ionizing irradiation. Anti-apoptotic Bcl2 expression is decreased but apoptotic Bax expression is increased with mitochondrial cytochrome c release in a time- dependent manner. In additon, expression of Fas and Fas-L is also increased in a time dependent manner. CONCLUSION: These data suggest that ionizing radiation-induced apoptosis is mediated by the activation of various signaling pathways including caspase family cysteine proteases, Bcl2/Bax, Fas and Fas-L in a time and dose dependent manner.

Cytotoxicity and Apoptosis of Various Concentrations of Doxorubicin in Methylcholanthrene-induced Rat Fibrosarcoma(MCA) Cells / 대한흉부외과학회지

BACKGROUND: Although pulmonary resection is the standard approach for the management of pulmonary metastases from soft tissue sarcoma, most of them are unresectable and chemotherapy remains the only option. The effectiveness of the cytotoxic drugs may be limited by the toxicities that occur before the therapeutic dose is reached. The regional administration of doxorubicin using pulmonary arterial perfusion in a rodent model can produce 10 to 25 times higher concentrations in the lung than systemic administration with minimal systemic toxicities. However, it is unclear whether a high concentration of doxorubicin has beneficial effects for killing cancer cells. MATERIAL AND METHOD: We studied this to evaluate the dose-dependent cytotoxic and apoptotic effects of doxorubicin on methylcholanthrene-induced rat fibrosarcoma(MCA) cells. This study examined the cytotoxicity and apoptosis-related gene expressions(Fas, FasL, Bax, caspase 1, caspase 2, caspase 8, Bcl-2, Bcl-xL, Bcl-xS) in MCA cells after 24 hours exposure to various concentrations of doxorubicin such as 1, 5, 10, 50, and 100 micrometer. RESULT: Dose-dependent cytotoxicity was observed after 24 hours exposure to doxorubicin. However, peak apoptosis after 24 hours exposure was observed at 5 micrometer of doxorubicin. Above 5 micrometer, apoptotic activity was decreased with dose-increment. All mRNA levels of apoptosis-related genes after 24 hours exposure were up-regulated above the control level at 1 micrometer of doxorubicin and then decreased by doxorubicin dose-increment except caspase 8, which showed higher levels than the control level at 5 micrometer. Apoptosis-related protein levels were highest at 1 micrometer of doxorubicin and then decreased by doxorubicin dose-increment. However, Bax and Bcl-xL proteins steadily showed higher levels than the control throughout the different concentrations of doxorubicin. CONCLUSION: These results suggest that apoptosis is the main cytotoxic mechanism in low concentrations of doxorubicin in MCA cells and apoptosis-related genes, such as Bax, caspase 8, a can kill MCA cells, even when apoptosis is inhibited, and have its propriety for achieving much cytotoxicity against MCA cells.