Impact of Taurine on the proliferation and apoptosis of human cervical carcinoma cells and its mechanism.

BACKGROUND: Cervical cancer has the fourth highest incidence and mortality rate of all cancers in women worldwide; it seriously harms their physical and mental health. The aim of this study was to observe the roles and preliminary mechanism of Taurine (Tau)-induced apoptosis in cervical cancer cells. METHODS: Cells from the human cervical cancer cell line SiHa were transfected with the recombinant plasmid pEGFP-N1-MST1 (mammalian sterile 20-like kinase 1); then, the cell proliferation activity was analyzed by the MTT assay, cell apoptosis by flow cytometry, and the related protein levels by Western blotting. RESULTS: Tau inhibited the proliferation of SiHa cells and induced apoptosis in these cells (the apoptotic rate was 21.95% in the Tau 160 mmol/L group and 30% in the Tau 320 mmol/L group), upregulated the expression of the MST1 (control, 0.53; Tau 40-320 mmol/L groups, 0.84-1.45) and Bax (control, 0.45; Tau 40-320 mmol/L groups, 0.64-1.51) proteins (P < 0.01), and downregulated the expression of Bcl-2 (control, 1.28, Tau 40-320 mmol/L groups, 0.93-0.47) (P < 0.01). The overexpression of MST1 promoted the apoptosis of SiHa cells, enhanced the apoptosis-inductive effects of Tau (P < 0.01), upregulated the expression of the proapoptotic proteins p73, p53, PUMA (p53 upregulated modulator of apoptosis), and caspase-3, and promoted the phosphorylation of YAP (Yes-associated protein). CONCLUSIONS: Tau inhibited the proliferation and induced the apoptosis of cervical cancer SiHa cells. The MST1 protein plays an important role in the Tau-induced apoptosis of cervical cancer cells.

Effect of taurine on cell proliferation and apoptosis human lung cancer A549 cells.

To investigate the effects of taurine on cell proliferation and apoptosis, the human lung cancer A549 cell line and xenograft tumors in nude mice were used. The effects of taurine on cell proliferation and apoptosis were observed at time points of 24, 48 and 72 h after treatment using an MTT assay to detect the survival rate, and flow cytometry to detect the apoptotic rate. Western blot analysis was performed to examine the levels of p53 upregulated modulator of apoptosis (PUMA), BCL2, apoptosis regulator (Bcl-2) and BCL2-associated X, apoptosis regulator (Bax) in A549 cells. The level of PUMA, Bax and Bcl-2 proteins in the mouse xenograft tumors treated with taurine and/or exogenous PUMA were assessed by immunohistochemistry, with taurine suppressing the proliferation of the human lung cancer A549 cell line in a concentration-dependent manner, and it significantly enhanced the apoptosis rate at all concentrations. Taurine induced the significant upregulation of PUMA and Bax, but led to downregulation of Bcl-2. In comparison to the control group, taurine treatment markedly reduced the volume and weight of A549-derived xenograft tumors in nude mice. Expression of PUMA and Bax were upregulated in the xenograft tumors following taurine treatment, whereas Bcl-2 was downregulated. In addition, the inhibitory effect of taurine and exogenous PUMA on tumor growth was significantly higher than that of a single treatment of taurine or exogenous PUMA. It can therefore be concluded that taurine can inhibit cell proliferation of the human lung cancer A549 cell line and the growth of the xenograft tumors, whereas PUMA serves an important role in taurine-induced growth suppression.

New Insights into the Role of Endoplasmic Reticulum Stress in Breast Cancer Metastasis.

Cellular stress severely disrupts endoplasmic reticulum (ER) function, leading to the abnormal accumulation of unfolded or misfolded proteins in the ER and subsequent development of endoplasmic reticulum stress (ERS). To accommodate the occurrence of ERS, cells have evolved a highly conserved, self-protecting signal transduction pathway called the unfolded protein response. Notably, ERS signaling is involved in the development of a variety of diseases and is closely related to tumor development, particularly in breast cancer. This review discusses recent research regarding associations between ERS and tumor metastasis. The information presented here will help researchers elucidate the precise mechanisms underlying ERS-mediated tumor metastasis and provide new directions for tumor therapies.

Exogenous p53 upregulated modulator of apoptosis (PUMA) decreases growth of lung cancer A549 cells.

PURPOSE: To investigate the influence of exogenous p53 upregulated modulator of apoptosis (PUMA) expression on cell proliferation and apoptosis in human non-small cell lung cancer A549 cells and transplanted tumor cell growth in nude mice. MATERIALS AND METHODS: A549 cells were divided into the following groups: control, non- carrier (NC), PUMA (transfected with pCEP4- (HA) 2-PUMA plasmid), DDP (10 µg/mL cisplatin treatment) and PUMA+DDP (transfected with pCEP4-(HA)2-PUMA plasmid and 10 µg/mL cisplatin treatment). The MTT method was used to detect the cell survival rate. Cell apoptosis rates were measured by flow cytometry, and PUMA, Bax and Bcl-2 protein expression levels were measured by Western blotting. RESULTS: Compared to the control group, the PUMA, DDP and PUMA+DDP groups all had significantly decreased A549 cell proliferation (p<0.01), with the largest reduction in the PUMA+DDP group. Conversely, the apoptosis rates of the three groups were significantly increased (P<0.01), and the PUMA and DDP treatments were synergistic. Moreover, Bax protein levels significantly increased (p<0.01), while Bcl-2 protein levels significantly decreased (p<0.01). Finally, both the volume and the weights of transplanted tumors were significantly reduced (p<0.01), and the inhibition ratio of the PUMA+DDP group was significantly higher than in the single DDP or PUMA groups. CONCLUSIONS: Exogenous PUMA effectively inhibited lung cancer A549 cell proliferation and transplanted tumor growth by increasing Bax protein levels and reducing Bcl-2 protein levels.

Effect of diallyl trisulfide on human ovarian cancer SKOV- 3/DDP cell apoptosis.

AIM: To investigate the effects of diallyl trisulfide (DT) on apoptosis of cisplatin (DDP)-resistant human epithelial ovarian cancer SKOV-3 cells (SKOV-3/DDP), and the role of p53 upregulated modulator of apoptosis (PUMA). METHODS: SKOV-3/DDP cells were randomly divided into control, DT, DPP and DPP+DT groups, which were treated with DT or combined DT and DDP. All cells were incubated for 48 h. and apoptosis rates were assessed by flow cytometry. mRNA and protein expression of PUMA, Bax and Bcl-2 was determined by RT-PCR and Western blot assays, respectively. RESULTS: Compared with control group, the apoptosis rates of SKOV-3/DDP cells in DT groups were obviously increased, with dose-dependence (P < 0.05), the mRNA and protein expressions of PUMA, Bax also being up-regulated (P < 0.05), while those of Bcl-2 were down-regulated (P < 0.05). Compared with DT groups, the apoptosis rate in the DDP+DT group was significantly increased (P < 0.05). After knockdown of PUMA with specific siRNA, the apoptosis rate of SKOV-3/DDP cells was obviously decreased (P < 0.05). CONCLUSION: DT can promote the apoptosis of SKOV-3/DDP cells with PUMA playing a critical role.

Inhibitory effect of p53 upregulated modulator of apoptosis targeting siRNA on hypoxia/reoxygenation-induced cardiomyocyte apoptosis in rats.

OBJECTIVES: The effect of p53 upregulated modulator of apoptosis (PUMA) in hypoxia/reoxygenation-induced cardiomyocyte injuries in rats was investigated. METHODS: PUMA-targeting (si-PUMA) and scramble siRNAs were designed and transfected into primarily rat cardiomyocytes in vitro. RESULTS: RT-PCR and Western blot analysis showed that 50 nmol/l of si-PUMA can specifically inhibit PUMA expression. MTT assay and lactate dehydrogenase activity detection showed that the cell survival rate in the si-PUMA group was enhanced and that the lactate dehydrogenase enzymatic activity dramatically decreased compared with the control group (p < 0.01). Spectrophotometry, as well as annexin V and propidium iodide staining, combined with flow cytometry, revealed that caspase-3 activity in the si-PUMA group was downregulated and the apoptotic rate was decreased (p < 0.01). RT-PCR also showed that Bax expression was downregulated and Bcl-2 expression was upregulated in the si-PUMA group, compared with the control group (p < 0.05). si-PUMA protects cardiomyocytes from apoptosis. CONCLUSION: PUMA mediates hypoxia/reoxygenation-induced cardiomyocyte apoptosis, which can be a potential target of gene therapy for ischemia/reperfusion cardiomyocyte injuries.

[Hippo signaling pathway in mammals: a new therapeutic target for tumors].

Hippo signaling pathway was first discovered in Drosophila as regulator of cell proliferation and apoptosis during development. It has been widely reported that Hippo signaling pathway plays an essential role in embryonic differentiation, pattern formation and adult cell homeostasis. Furthermore, Hippo signaling has close correlation with Wnt and Notch signaling pathways, and has an important effect on tumor initiation and progression. Recent studies have shown that the Drosophila Hippo signaling pathway is highly conserved over evolutionary time, the mammalian Hippo signaling pathway has been implicated in regulating cell contact inhibition, organsize and tumorigenesis. This review firstly focuses on the composition, regulatory mechanism and physiological functions of mammalian Hippo signaling pathway, and then lists the relationship with other signaling pathways and protein factors, and tumors in mammals. Finally, the therapeutic approaches to targeting Hippo signaling pathway components or regulators have also been summarized, which might be beneficial to tumor therapeutic intervention.

[Study on apoptosis of human stomach SGC-7901 cells induced by extracts of Solanum lyratum].

OBJECTIVE: To investigate the effects of extracts of Solanum lyratum (ESL) on the apoptosis of Human stomach cancer SGC-7901 cells. METHODS: Dried whole herbs of Solanum lyratum were extracted by boiling distilled water. SGC-7901 cells were randomly divided into control group, ESL-treated groups (12.5 g/L, 25 g/L, 50 g/L) and the positive control (25 mg/L DDP) group. The growth inhibitory rate was evaluated by MTT assay. Morphological changes of apoptosis were observed with fluorescence microscope. Cell apoptosis rate was determined by flow cytometry. Expressions of bcl-xl, Caspase-9 and bid mRNA were detected by semi-quantitive RT-PCR. The activity of Caspase-3 was detected by Fluorospectrophotometry. RESULTS: Compared with control group, the cell proliferation inhibitory rate and apoptosis rate of human stomach cancer SGC-7901 cells increased obviously (P < 0.05). There were obvious changes of morphology of the SGC-7901 cells as the nuclear shrinkage, chromatin condensation and margination; The expression of bcl-xl mRNA decreased obviously (P < 0.05), the expression of Caspase-9 and bid mRNA increased obviously respectively (P < 0.05), and displayed effect in a dose-dependent manner in the SGC-7901 cells of the ESL-treated groups. The activity of Caspase-3 in the SGC-7901 cells of the ESL-treated groups were higher than that of the control group significantly (P < 0.01). CONCLUSION: ESL can induce apoptosis and inhibit proliferation of the human stomach cancer SGC-7901 cells by regulating expression of bcl-xl, Caspase-9 and bid genes and strengthening the activity of Caspase-3.

[Protective effects of taurine on myocardial mitochondria and their enzyme activities in rate with severe burn].

OBJECTIVE: To investigate the effects of taurine on myocardial mitochondria and their enzyme activities in rats with severe burn. METHODS: One hundred and twenty healthy adult Wistar rats were subjected to 30% TBSA full-thickness burn. They were randomly divided into burn group (B, with intraperitoneal injection of isotonic saline), treatment group (T, with intraperitoneal injection of taurine, 200 mg/kg),with 60 rats in each group . Ten rats with sham scald were used as control (S group). The myocardial tissue samples in B and T groups were harvested at 1, 3, 6, 12, 24 and 48 postburn hours (PBH) for determination of activity respectively of succinate dehydrogenase (SDH), cytochrome oxidase (CCO), the superoxide dismutase (SOD), Ca2+ -ATPase in mitochondria, and contents of cytochrome c (Cyt c), cytochrome aa3 (Cyt aa3), malondialdehyde (MDA), and Ca2+ in mitochondria and cytoplasm . The myocardial tissue samples of controls were harvested at 1 PBH for determination of above indices. RESULTS: The activity of CCO in B group was decreased at 1 PBH , especially at 6 ,12 PBH. The activity of SDH in B group was decreased to lowest level at 6 PBH, and its value was lower than that of S group at each time point. The activity of CCO or SDH in T group was not obviously decreased, and the activity of CCO at 3, 6, 12 PBH showed significant difference compared with B group (P < 0.05). The contents of Cyt aa3 and Cyt c in B group at 3, 6, 12, 24 PBH were obviously decreased, which were significantly lower than those in T group (P < 0.05). The activity of SOD in B group at 3, 6, 12 PBH was obviously decreased, the activity of Ca2+ -ATPase at 3, 6, 12 and 24 PBH was decreased to different extent, which was significantly lower than those in T group (P < 0.05). The MDA contents in B and T groups were higher than that in S group at 3-48 PBH ,and it was highest in B group (P < 0.05). The Ca2+ content of mitochondria in B group at 1 PBH was increased (13.7 +/- 1.5), and it was (24.8 +/- 2.6), (29.7 +/- 3.1), (16.3 +/- 1.9) and (13.5 +/- 1.7) at 3, 6, 12, 24 PBH respectively,and they were all higher than that of S group (10.7 +/- 1.6, P < 0.05). The Ca2 contents of cytoplasm in group B at 3 - 24 PBH were also higher than that in S group (P < 0.05). The Ca2+ content of mitochondria in T group at 3, 6, 12, 24 PBH was (16.8 +/- 2.8), (18.7 +/- 1.9), (10.5 +/- 1.8) and (13.3 +/- 1.7)respectively, which were lower than that in B group at every time point. CONCLUSION: Taurine have protective effect on mitochondria and their enzyme activities in myocardium in rats with severe burn, and it may be attributable to improving the ability of eradicating oxygen free radicals and alleviating Ca2+ overload in the mitochondria.

[Protective effects of taurine on myocardial injury in severely burned rats].

OBJECTIVE: To investigate the effect of taurine on myocardial injury in severely scalded rats. METHODS: A total of 130 healthy adult Wistar rats were randomly divided into 3 groups: the control group (C, without burns), the burn group (B, subjected to a 30% TBSA III degree scalding) and the treatment group (T, treated with intraperitoneal injection of taurine (400 mg/kg) immediately after scald injury). The plasma and myocardial tissue samples in B and T groups were harvested at 1, 3, 6, 12, 24 and 48 postburn hours (PBH) for the determination of the contents of cardiac troponin T (cTnT), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-alpha), and angiotensin II (AngII) in plasma, and the contents of TNF-alpha, AngII and calcium ion in myocardial tissue. The morphological change in the myocardial tissue was observed with transmission electronic microscope (TEM) and was compared with that in C group. The changes in the plasma TNF-alpha and AngII were analyzed in relation to that of plasma cTnT. RESULTS: The plasma cTnT content in B group at 3 PBH was markedly higher than that in C group (0.16 +/- 0.03 microg/L) (P < 0.01), and it peaked (6.32 +/- 0.41) at 12 PBH and remained at high level at 48 PBH. While the plasma MDA content and the calcium ion level in B group were evidently higher than those in C group during 3 to 48 PBH (P < 0.01). The TNF-alpha contents in plasma and myocardial tissue during 6 to 48 PBH were significantly higher than those in C group (P < 0.01). The AngII contents in plasma and myocardial tissue during 3 to 24 PBH were obviously higher than those in C group (P < 0.01). All the indices in T group were significantly lower than those in B group (P < 0.01). Histological examination revealed that there was myocardial damage in various degrees during early postburn stage in B group, such as focal dissolution and fragmentation of myofilament, mitochondrial edema, myocyte sarcoplasmic protrusions like piano keys. But all the above changes in T group were evidently ameliorated to near normal. There was close positive correlation between the change in the concentrations of plasma content of TNF-alpha and AngII and cTnT in B group (r = 0.87 and 0.82, P < 0.05). CONCLUSION: The production of TNF-alpha, MDA, cTnT, AngII and high calcium ion level of myocardiocytes in severely burned rats can be inhibited by taurine, which was beneficial in the management of myocardial injury after severe burns.