Purpose: Signal transducer and activator of transcription 3 (Stat3) protein is persistently activated in breast cancer and promotes tumor cell survival. To gain a better understanding of the role of constitutive Stat3 signaling in breast cancer progression, we evaluated the expression profile of potential Stat3-regulated genes that may confer resistance to apoptosis. Experimental Design: Stat3 signaling was blocked with antisense oligonucleotides in human MDA-MB-435s breast cancer cells and Affymetrix GeneChip microarray analysis was done. The candidate Stat3 target gene Survivin was further evaluated in molecular assays using cultured breast cancer cells and immunohistochemistry of breast tumor specimens. Results: Survivin, a member of the inhibitor of apoptosis protein family, was identified as a potential Stat3-regulated gene by microarray analysis. This was confirmed in Survivin gene promoter studies and chromatin immunoprecipitation assays showing that Stat3 directly binds to and regulates the Survivin promoter. Furthermore, direct inhibition of Stat3 signaling blocked the expression of Survivin protein and induced apoptosis in breast cancer cells. Direct inhibition of Survivin expression also induced apoptosis. Increased Survivin protein expression correlates significantly (P = 0.001) with elevated Stat3 activity in primary breast tumor specimens from high-risk patients who were resistant to chemotherapy treatment. Conclusions: We identify Survivin as a direct downstream target gene of Stat3 in human breast cancer cells that is critical for their survival in culture. Our findings suggest that activated Stat3 signaling contributes to breast cancer progression and resistance to chemotherapy by, at least in part, inducing expression of the antiapoptotic protein, Survivin.

Standard methods to measure recreational water quality require at least 24 hr to obtain results, making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in ≤ 2 hr have been developed. Application of rapid methods could give considerably more accurate and timely assessments of recreational water quality. We conducted a prospective study of beachgoers at two Great Lakes beaches to examine the association between recreational water quality, obtained using rapid methods, and gastrointestinal (GI) illness after swimming. Beachgoers were asked about swimming and other beach activities and 10–12 days later were asked about the occurrence of GI symptoms. We tested water samples for Enterococcus and Bacteroides species using the quantitative polymerase chain reaction (PCR) method. We observed significant trends between increased GI illness and Enterococcus at the Lake Michigan beach and a positive trend for Enterococcus at the Lake Erie beach. The association remained significant for Enterococcus when the two beaches were combined. We observed a positive trend for Bacteroides at the Lake Erie beach, but no trend was observed at the Lake Michigan beach. Enterococcus samples collected at 0800 hr were predictive of GI illness that day. The association between Enterococcus and illness strengthened as time spent swimming in the water increased. This is the first study to show that water quality measured by rapid methods can predict swimming-associated health effects.

Fig. 1. Apoptosis induction by lenalidomide is specific for 5q-deleted cells. (A) Cells from AML that evolved from MDS patients with (Center) or without (del) 5q and U937 cells (Left and Right) were exposed to lenalidomide, thalidomide, or vehicle (DMSO) at the concentrations indicated for 48 h before apoptosis was assessed by flow cytometry using Annexin-V/PI staining. Representative results are shown as the mean of the triplicate measurement ± SD from 1 patient. A total of 5 different MDS patients were tested. (B) Lenalidomide arrests 5q deleted cells in G 2 . Cells were treated with lenalidomide at the concentration of 1 μM for 48 h at 37°C and stained with propidium Iodide (PI) in BD Stain Buffer (10 6 /ml) before analysis on BD FACScan. (C) FISH analysis of haplo-deficiency of Cdc25C in (del)5q cells. A normal chromosome 5 showing FISH signals for D5S23/D5S721 (green) and Cdc25C (orange); the ideogram demonstrates the relative gene locations of EGR1 and Cdc25C in 5q31. Probes for EGR1 are commonly used to detect classical 5q deletions. The Right Inset illustrates D5S23/D5S721 and Cdc25C signal pattern for classical 5q deletions in interphase nuclei. (D) Reduced expression of Cdc25C and PP2Acα in bone marrow cells from patients with (del)5q by Q-PCR. RNA was purified from BM-MNC from patients with or without (del)5q as indicated. Relative expression levels of Cdc25C and PP2Acα were analyzed by Q-PCR to quantitate transcript level. Expression is normalized to the reference gene (GAPDH) and fold changes for Cdc25C and PP2Acα in patients are compared with the average data from non(del)5q cells (P < 0.001).

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Dasatinib (BMS-354825) is a novel, oral, potent, multitargeted kinase inhibitor of Bcr-Abl and Src family kinases (SFK) and is a promising cancer therapeutic agent. Preclinical data indicate that dasatinib is 325-fold more potent than imatinib against cells expressing wild-type Bcr-Abl, and that dasatinib is active against 18 of 19 Bcr-Abl mutations known to cause imatinib resistance. Phase I clinical data show that dasatinib is well tolerated and highly effective for the treatment of imatinib-resistant/ imatinib-intolerant chronic myelogenous leukemia (CML) and Philadelphia chromosome -positive acute lymphoblastic leukemia. However, the molecular mechanism of action of dasatinib is not fully understood. In this study, we confirm that dasatinib inhibits tyrosine phosphorylation of SFKs, including Src, Hck, and Lyn, in K562 human CML cells. Significantly, downstream signal transducer and activator of transcription 5 (Stat5) signaling is also blocked by dasatinib as shown by decreases in levels of phosphorylated Stat5 and Stat5 DNA-binding activities. In addition, dasatinib down-regulates expression of Stat5 target genes, including Bcl-x, Mcl-1, and cyclin D1. Consistent with these results, blockade of Stat5 signaling by dasatinib is accompanied by inhibition of cell proliferation and induction of apoptosis. Surprisingly, Stat5 DNA-binding activities are enhanced with increasing cell density, which is associated with resistance to apoptosis by dasatinib. Our findings indicate that inhibition of Stat5 signaling downstream of Bcr-Abl/SFKs contributes to the action of dasatinib, and, conversely, that increasing cell density up-regulates Stat5 activation and confers resistance to dasatinib. Moreover, the level of phosphorylated Stat5 in CML cells represents a mechanistically relevant biomarker for monitoring inhibition of Bcr-Abl signaling by dasatinib in CML patients using convenient immunocytochemical assays.

Parental smoking, birth weight, and not eating dinner as a family were two modifiable factors associated with overweight and obesity in kindergarten-age children, regardless of socioeconomic status. Changing these life-style factors could reduce the child's risk for obesity.

Manipulative field experiments were used to test for the existence of competitive interactions between three abundant herbivore species in a shallow back—reef zone. Densities of the territorial threespot damselfish, Eupomacentrus planifrons, and two sea urchins, Diadema antillarum and Echinometra viridis, were altered through addition and removal experiments conducted within patches of staghorn coral, Acropora cervicornis. Removals of each urchin species resulted in population increases of the other urchin. Additions of each urchin species tended to inhibit increases of the other species. Removals of damselfish resulted in increases of the other species. Removals of damselfish resulted in increases in Diadema density within 24 h, while Echinometra density increased during the 3rd d following the perturbation. Dry biomass of algae on ceramic tiles in the lower strata of damselfish removal patches was reduced by 62% as compared with algal biomass in these strata in the presence of damselfish. Wire mesh cages were utilized over a 2—mo period to test the effect of predation on competition at the herbivore level. No significant alteration of species numbers was observed in the absence of predation. Therefore, predation did not appear to affect significantly the distributions and abundances of the adult members of the community. Low predation levels on adults within this system do not appear to alter the competitive interactions between these herbivores. Interference competition by the threespot damselfish appears to mediate competition between the two echinoids, allowing coexistence of all species. The presence of damselfish may reduce destructive echinoid grazing pressure on the coral substrate.