Secreted frizzled-related protein 1 loss contributes to tumor phenotype of clear cell renal cell carcinoma.

PURPOSE: Incidence and mortality rates for renal cell carcinoma (RCC) have been rising for decades. Unfortunately, the molecular events that support RCC carcinogenesis remain poorly understood. In an effort to gain a better understanding of signaling events in clear cell RCC (cRCC), we investigated the antitumor activity of secreted frizzled-related protein 1 (sFRP1), a negative regulator of Wnt signaling. EXPERIMENTAL DESIGN: Genomic profiling of cRCC tumors and patient-matched normal tissues was done and confirmed using quantitative PCR and immunohistochemistry. Methylation-specific PCR was done on patient samples to evaluate the mechanism responsible for sFRP1 loss. sFRP1 expression was restored in cRCC cells and the effects on tumor phenotype were characterized. RESULTS: Genomic profiling, quantitative PCR, and immunohistochemistry indicated that loss of sFRP1 occurred in cRCC and papillary RCC patient tissues. Twelve Wnt-regulated genes were up-regulated in cRCC tissues, including c-myc and cyclin D1, potentiators of cell proliferation and survival. Methylation of the sFRP1 gene was one mechanism identified for attenuation of sFRP1 mRNA. Stable reexpression of sFRP1 in cRCC cells resulted in decreased expression of Wnt target genes, decreased growth in cell culture, inhibition of anchorage-independent growth, and decreased tumor growth in athymic nude mice. CONCLUSIONS: To our knowledge, this is the first report to show that stable restoration of sFRP1 expression in cRCC cells attenuates the cRCC tumor phenotype. Our data support a role for sFRP1 as a tumor suppressor in cRCC and that perhaps loss of sFRP1 is an early, aberrant molecular event in renal cell carcinogenesis.

Doxorubicin treatment in vivo causes cytochrome C release and cardiomyocyte apoptosis, as well as increased mitochondrial efficiency, superoxide dismutase activity, and Bcl-2:Bax ratio.

There have been very few investigations as to whether mitochondrial-mediated apoptosis in vivo is the underlying mechanism of doxorubicin cardiotoxicity. Moreover, no investigations have been conducted to determine whether there are adaptive responses after doxorubicin treatment. We administered a single dose of doxorubicin (20 mg/kg) to male rats and isolated intact mitochondria from their hearts 4 days later. Apoptosis, as determined by the amount of cytosolic mononucleosomal and oligonucleosomal DNA fragments (180 bp or multiples), was significantly increased after doxorubicin treatment. In contrast, Troponin-T, a cardiac-specific marker for necrotic damage, was unaltered 4 days after doxorubicin treatment. Cytosolic cytochrome c increased 2-fold in the doxorubicin-treated rats and was significantly correlated (r = 0.88; P < 0.01) with the increase in caspase-3 activity observed. Moreover, the level of bleomyocin-detectable iron in serum was significantly increased and may have contributed to the increase in oxidative stress, which was indicated by an increase in cytosolic 8-iso prostaglandin F(2alpha). Cytosolic copper zinc superoxide dismutase activity also increased significantly further supporting the notion that doxorubicin increases superoxide radical production. In addition to adaptations to antioxidant defenses, other adaptive mechanisms occurred in the mitochondria such as an increase in the respiratory P/O ratio and an increase in the Bcl-2:Bax ratio. These findings demonstrate that doxorubicin induces oxidative stress and mitochondrial-mediated apoptosis, as well as adaptive responses by the mitochondria to protect cardiac myocytes in vivo.

A dietary supplement attenuates IL-6 and CRP after eccentric exercise in untrained males.

PURPOSE: This study investigated the effects of a dietary supplement on exercise-induced markers of cell damage and the inflammatory mediators C-reactive protein (CRP) and interleukin-6 (IL-6). METHODS: The supplement contained mixed tocopherols, flavonoids, and docosahexaenoate. Forty healthy, nonsmoking, untrained males (aged 18-35 yr) were randomly assigned to receive either the supplement (N = 20) or placebo (N = 20) during the 14-d experimental protocol. Blood samples were collected on day 0 (baseline), day 7 (eccentric exercise-induced injury), day 10, and day 14. OBJECTIVE: Markers of cell damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) and inflammation IL-6 and CRP were assessed at these time points in conjunction with subjective range of motion (ROM) and perceived pain measurements. Statistical analyses were conducted using nonparametric methods (P < 0.05). RESULTS: Eccentric arm curl exercise was used to induce an acute phase injury response as evidenced by significant (P < 0.0001) increases in CK, LDH, and pain, as well as a decreased range of motion 3 d after the exercise. There were no significant differences between groups in CK and LDH responses. In contrast, there were significant group differences for IL-6 (P = 0.008) and CRP (P = 0.003). At day 10, by Mann-Whitney U test of changes, the placebo group had significantly greater increases in IL-6 and CRP than the treatment group (P = 0.05 and P < 0.01), respectively. CONCLUSION: This study suggested that exercise-induced inflammation, evaluated by changes in IL-6 and CRP, was significantly reduced by the dietary supplement.