Gliclazide may have an antiapoptotic effect related to its antioxidant properties in human normal and cancer cells

Experimental and clinical studies suggest that gliclazide may protect pancreatic β-cells from apoptosis induced by an oxidative stress. However, the precise mechanism(s) of this action are not fully understood and requires further clarification. Therefore, using human normal and cancer cells we examined whether the anti-apoptotic effects of this sulfonylurea is due to its free radical scavenger properties. Hydrogen peroxide (H2O2) as a model trigger of oxidative stress was used to induce cell death. Our experiments were performed on human normal cell line (human umbilical vein endothelial cell line, HUVEC-c) and human cancer cell lines (human mammary gland cell line, Hs578T; human pancreatic duct epithelioid carcinoma cell line, PANC-1). To assess the effect of gliclazide the cells were pre-treated with the drug. The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was employed to measure the impact of gliclazide on cell viability. Generation of reactive oxygen species, mitochondrial membrane potential (∆Ψm), and intracellular Ca2+ concentration [Ca2+] were monitored. Furthermore, the morphological changes associated with apoptosis were determined using double staining with Hoechst 33258-propidium iodide (PI). Gliclazide protects the tested cells from H2O2-induced cell death most likely throughout the inhibition of ROS production. Moreover, the drug restored loss of ΔΨm and diminished intracellular [Ca2+] evoked by H2O2. Double staining with Hoechst 33258-PI revealed that pre-treatment with gliclazide diminished the number of apoptotic cells. Our findings indicate that gliclazide may protect both normal and cancer human cells against apoptosis induced by H2O2. It appears that the anti-apoptotic effect of the drug is most likely associated with reduction of oxidative stress

The histone deacetylase inhibitor trichostatin A downregulates human MDR1 (ABCB1) gene expression by a transcription-dependent mechanism in a drug-resistant small cell lung carcinoma cell line model

Tumour drug-resistant ABCB1 gene expression is regulated at the chromatin level through epigenetic mechanisms. We examined the effects of the histone deacetylase inhibitor trichostatin A (TSA) on ABCB1 gene expression in small cell lung carcinoma (SCLC) drug-sensitive (H69WT) or etoposide-resistant (H69VP) cells. We found that TSA induced an increase in ABCB1 expression in drug-sensitive cells, but strongly decreased it in drug-resistant cells. These up- and downregulations occurred at the transcriptional level. Protein synthesis inhibition reduced these modulations, but did not completely suppress them. Differential temporal patterns of histone acetylation were observed at the ABCB1 promoter: increase in H4 acetylation in both cell lines, but different H3 acetylation with a progressive increase in H69WT cells but a transient one in H69VP cells. ABCB1 regulations were not related with the methylation status of the promoter −50GC, −110GC, and Inr sites, and did not result in further changes to these methylation profiles. Trichostatin A treatment did not modify MBD1 binding to the ABCB1 promoter and similarly increased PCAF binding in both H69 cell lines. Our results suggest that in H69 drug-resistant SCLC cell line TSA induces downregulation of ABCB1 expression through a transcriptional mechanism, independently of promoter methylation, and MBD1 or PCAF recruitment

Clinical applications of image cytometry to human tumour analysis

Image cytometry (ICM) is widely applied to the automated screening, the detection, the diagnosis, the classification, the prognosis and the therapeutic followup of different types of cancers (breast, bladder, cervix,. . .). This review describes the analysis methods and the applications of nuclear image analysis, the determination of DNA content and the analysis of morphometry and of nuclear texture. DNA content analysis can contribute to a prognostic information in addition to other prognostic factors for breast, renal and prostate cancers. For ovarian cancer, aneuploidy seems to be related to prognosis. Bladder tumours with DNA aneuploidy were frequently of high malignancy while ploidy was significantly correlated to relapse risk. For digestive cancers, patients presenting DNA diploid tumours show a better survival than patients with aneuploid ones. Morphometry seems to be a more important criterion than other conventional prognostic factors of invasive breast and digestive carcinomas. A differential diagnosis between normal and neoplastic thyroids is more precise when based on a quantitative evaluation of texture associated to morphometry. Textural parameters permit the discrimination of two populations of patients having a different prognosis and could thus be an aid for prognosis in prostatic cancers. Morphonuclear parameters contribute to separate low and high grade bladder carcinomas. Although ICM was frequently reported, results from the reported examples were not always obvious. In conclusion, the measurements obtained with ICM could be helpful for a decision in several cancers but could not be a substitute for the classical approach of the pathologist

Clinical applications of image cytometry to human tumour analysis

Image cytometry (ICM) is widely applied to the automated screening, the detection, the diagnosis, the classification, the prognosis and the therapeutic followup of different types of cancers (breast, bladder, cervix,. . .). This review describes the analysis methods and the applications of nuclear image analysis, the determination of DNA content and the analysis of morphometry and of nuclear texture. DNA content analysis can contribute to a prognostic information in addition to other prognostic factors for breast, renal and prostate cancers. For ovarian cancer, aneuploidy seems to be related to prognosis. Bladder tumours with DNA aneuploidy were frequently of high malignancy while ploidy was significantly correlated to relapse risk. For digestive cancers, patients presenting DNA diploid tumours show a better survival than patients with aneuploid ones. Morphometry seems to be a more important criterion than other conventional prognostic factors of invasive breast and digestive carcinomas. A differential diagnosis between normal and neoplastic thyroids is more precise when based on a quantitative evaluation of texture associated to morphometry. Textural parameters permit the discrimination of two populations of patients having a different prognosis and could thus be an aid for prognosis in prostatic cancers. Morphonuclear parameters contribute to separate low and high grade bladder carcinomas. Although ICM was frequently reported, results from the reported examples were not always obvious. In conclusion, the measurements obtained with ICM could be helpful for a decision in several cancers but could not be a substitute for the classical approach of the pathologist