1,720,977 research outputs found
Hypocrellin B-Acetate-mediated photodynamic activation drives HeLa cells to apoptotic death
No full textThe work describes the apoptotic effect of Hypocrellin B-Acetate-mediated photodynamic activation on HeLa cell
Multicolor fluorescence technique to detect apoptotic cells in advanced coronary atherosclerotic plaques
No full textIpocrellina B-acetato e induzione di danni fototossici a livello subcellulare
No full textIl lavoro descrive gli effetti pro-apoptotici che un trattamento con Ipocrellina B-acetato induce in cellule HeL
Functional analysis and case-control study of -160C/A polymorphism in the E-cadherin gene promoter: association with cancer risk.
No full textBACKGROUND:
A C-->A polymorphism within the CDH1 (E-cadherin) promoter seems to be associated with a reduced efficiency of gene transcription in vitro. Due to the crucial role of E-cadherin in epithelia, tissue-specific effect of C-->A change on CDH1 transcription was tested and a case-control study was performed on patients affected with epithelial tumors.
PATIENTS AND METHODS:
The -178/+93 CDH1 region containing either C or A nucleotide was inserted upstream of the Luciferase reporter gene in the pGL-2 vector, and the construct activity was assessed by transient transfection assay in HeLa and HCT116 cells.
RESULTS:
A significantly lower activity for pGL-2A was found compared to pGL-2C, both in HeLa (54% decrease) and in HCT116 (67% decrease) cells. Genotyping of 246 controls and 505 patients affected with breast, gastric, colorectal, cervical and endometrial cancers demonstrated an association between the A allele and an increased risk of colorectal, gastric and endometrial tumors (1.66-, 1.81- and 2.35-fold, respectively).
CONCLUSION:
Our data support the notion that the A allele may act as a low-penetrance cancer susceptibility gene
Anthocyanins induce cell cycle perturbations and apoptosis in different human cell lines
No full textTo investigate the mechanistic basis for the biological properties of anthocyanins, two aglycone anthocyanins [delphinidin (DY) and cyanidin (CY)] were used to examine their effects on cell cycle progression and on induction of apoptosis in human cancer cells (uterine carcinoma and colon adenocarcinoma cells) and in normal human fibroblasts. These compounds differ in the number and position of hydroxyl groups on the beta ring in the molecular structure. Cellular uptake of anthocyanins was confirmed by HPLC analysis and no metabolites were detected. The clonogenic assay showed that CY induces a dose-dependent growth inhibitory effect only in fibroblasts. This effect was confirmed by flow cytometric analysis, showing a significant reduction of cells in S phase. In contrast, DP inhibited cell growth in normal and tumour cell lines. This event is accompanied in fibroblasts by an accumulation of cells in the S phase suggesting a block in the transition from S to G2 phase. On the other hand, in tumour cell lines we observed a reduction of cells in G1 phase, paralleled by the appearance of a fraction of cells with a hypodiploid DNA content, thus demonstrating an apoptotic effect by DP. The occurrence of apoptosis induced by DP was confirmed by morphological and biochemical features, including nuclear condensation and fragmentation, annexin V staining, DNA laddering and poly(ADP-ribose) polymerase-1-proteolysis. Furthermore, the mitochondrial membrane potential of apoptotic cells after treatment with DP was significantly lost. The different effects exerted by DP as compared with CY suggest that the presence of the three hydroxyl groups on the beta ring in the molecular structure of DP may be important for its greater biological activity
Multiple effects of the Na(+)/H (+) antiporter inhibitor HMA on cancer cells.
No full textAmiloride derivatives are a class of new promising chemotherapeutic agents. A representative member of this family is the sodium-hydrogen antiporter inhibitor HMA (5-(N,N-hexamethylene amiloride), which has been demonstrated to induce cellular intracytosolic acidification and cell death through the apoptotic pathway(s). This work aims at characterizing drug response of human cancer cell lines to HMA. After a first screening revealing that HMA interferes with cancer cell survival, we focused our attention on SW613-B3 colon carcinoma cells, which are intrinsically resistant to a panel of drugs. Searching for the activation of canonical apoptosis, we found that this process was abortive, given that the final steps of this process, i.e. PARP-1 cleavage and DNA ladder, were not detectable. Thus, we addressed caspase-independent paradigms of cell death and we observed that HMA promotes the induction of the LEI/L-DNase II pathway as well as of parthanatos. Finally, we explored the possible impact of autophagy of cell response to HMA, providing the evidence that autophagy is activated in our experimental system. On the whole, our results defined the biochemical reactions triggered by HMA, and elucidated its multiple effects, thus adding further complexity to the intricate network leading to drug resistance
The cyclin-dependent kinase inhibitors Olomoucine and Roscovitine arrest human fibroblasts in G1 phase by specific inhibition of CDK2 kinase activity.
No full textThe specificity and the temporal location of cell cycle arrest induced by the cyclin-dependent kinase (CDK) inhibitors olomoucine and roscovitine were investigated in normal human fibroblasts. Effects on the cell cycle were compared with those induced by the kinase inhibitor staurosporine, which arrests normal cells in early G1 phase by acting upstream of CDK2. Consistent with their in vitro activity, olomoucine and roscovitine, but not the related compound iso-olomoucine, induced a dose-dependent arrest in G1 phase. Following removal of CDK inhibitors, cells resumed cycle progression entering S phase with a kinetics faster than staurosporine-treated samples. Cellular levels of PCNA, cyclin D1, and cyclin E were not affected by the CDK inhibitors. In contrast, staurosporine significantly reduced the levels of these proteins, as determined by immunocytometry and Western blot analysis. Cyclin A was detectable only in some cells remaining in the G2 + M compartment of samples treated with CDK inhibitors, but not in samples treated with staurosporine. Significant reduction in the hyperphosphorylated forms of retinoblastoma protein was found in samples treated with CDK inhibitors, while only hypophosphorylated forms were observed in staurosporine-treated samples. Concomitantly, CDK2, but not CDK4, activity immunoprecipitated from cells treated with olomoucine or roscovitine was markedly inhibited. These results suggest that in normal cells, CDK2 kinase activity is the specific target of olomoucine and roscovitine
Functional analysis and case-control study of -160C/A polymorphism in the E-cadherin gene promoter: association with cancer risk
No full textBackground: A C→A polymorphism within the
CDH1 (E-cadherin) promoter seems to be associated with a
reduced efficiency of gene transcription in vitro. Due to the
crucial role of E-cadherin in epithelia, tissue-specific effect of
C→A change on CDH1 transcription was tested and a case-control study was performed on patients affected with epithelial tumors. Patients and Methods: The –178/+93 CDH1 region containing either C or A nucleotide was inserted upstream of the Luciferase reporter gene in the pGL-2 vector, and the construct activity was assessed by transient transfection assay in HeLa and HCT116 cells. Results: A significantly lower activity for pGL-2A was found compared to pGL-2C, both in HeLa (54% decrease) and in HCT116 (67% decrease) cells. Genotyping of 246 controls and 505 patients affected with breast, gastric, colorectal, cervical and endometrial cancers demonstrated an association between the A allele and an increased risk of colorectal, gastric and endometrial tumors (1.66-, 1.81- and 2.35-fold, respectively). Conclusion: Our data support the notion that the A allele may act as a low-penetrance cancer susceptibility gene
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