Deficient activation of apoptosis signaling pathways may be responsible for treatment failure of malignant diseases. In primary leukemia samples the detection of deficient mitochondrial apoptosis signaling would enable identification of chemo-resistant cells. To investigate the key events of apoptosis at the mitochondrial level, we developed a flow cytometric method for simultaneous detection of mitochondrial cytochrome c release and caspase-3 processing using conformation sensitive monoclonal antibodies. This method proved to identify deficient mitochondrial apoptosis signaling in leukemia cells overexpressing Bcl-2 by a pattern of apoptosis resistance, deficient cytochrome c reduction and partial processing of caspase-3. In primary leukemia cells, reduction of cytochrome c and caspase-3 activation was induced by treatment with anticancer drugs in vitro. In leukemia cells of a patient with resistant disease, a pattern of deficient apoptosis signaling as in Bcl-2 transfected cells was observed, suggesting that deficient mitochondrial signaling contributed to the clinical phenotype of drug resistance in this patient. Flow cytometric analysis of mitochondrial apoptosis signaling may provide a useful tool for the prediction of drug resistance and treatment failure in primary leukemia.

Zinc finger protein X-linked (ZFX) is a highly conservative mammalian gene with related functions in cell survival and proliferation. However, there are limited reports on regulation of ZFX as a therapeutic target in cancer treatment. In this study, the expression of ZFX in prostate cancer with matched normal adjacent tissues (n ¼ 45) and benign prostatic hyperplasia (BPH) tissues (n ¼ 16) were observed by immunohistochemical analysis. The effect of lentiviral siRNA (small interference RNA)-mediated dysfunction of ZFX on the proliferation of prostate cancer cells was studied. ZFX mRNA and protein expression levels in prostate cancer cells (PC-3 and DU145) were analyzed by western blotting and real-time polymerase chain reaction (RT-PCR). The effects of siRNA targeting ZFX on growth, cell cycle and apoptosis of PC-3 cells were evaluated by MTT assay and flow cytometry. We also investigated the effect of ZFX deletion on the activation of caspase-1, -3 and -9 by western blotting and colorimetric assay. Prostate cancer specimens appeared significantly higher (42.2% of cases being positive) than that observed in normal adjacent tissues (11.8% of cases being positive) and BPH tissues (12.5% of cases being positive). Repression of ZFX in the prostate cancer cells effectively suppressed the cellular proliferation and colony-formation ability, and led to G1 phase cell cycle arrest. Moreover, inhibition of ZFX-induced cell apoptosis by activating caspase-1, -3 and -9. In conclusion, ZFX represents the prominent role in the progression of prostate cancer and may be a promising therapy target for prostate cancer.

This study was designed to investigate adiponectin levels and their relationship to various parameters at baseline and after 5 years in non-obese first-degree relatives of type 2 diabetes patients (FDR group) versus subjects without a family history of diabetes (normal group). Adiponectin levels at baseline were lower in the FDR group versus the normal group. After 5 years, adiponectin levels had fallen significantly in both the FDR (24.3% reduction) and the normal (35.7% reduction) groups. Adiponectin levels were negatively correlated with waist/hip ratio, fasting plasma glucose, carotid intima-media thickness (IMT) and insulin resistance in the FDR group. When adjusted for relevant risk factors, adiponectin was associated with age, high-density lipoprotein-cholesterol and IMT; these factors explained 45% of the variation in adiponectin in the FDR group. In the normal group, multiple regression analyses revealed that low-density lipoprotein-cholesterol and IMT explained 25% of the variability in the adiponectin concentration. In both groups, however, the correlation between adiponectin and IMT just failed to reach statistical significance in this population group. We conclude that adiponectin levels were reduced in non-obese first-degree relatives of patients with type 2 diabetes and normal individuals over a 5-year period. This study supports previous findings that hypoadiponectinaemia is a risk factor for atherosclerosis.

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