Fatty acid synthase (FAS) activity is a potential therapeutic target to treat cancer and obesity. Here, we have identified a molecular link between FAS and HER2 (erbB-2) oncogene, a marker for poor prognosis that is overexpressed in 30% of breast and ovarian cancers. Pharmacological FAS inhibitors cerulenin and C75 were found to suppress p185 HER2 oncoprotein expression and tyrosinekinase activity in breast and ovarian HER2 overexpressors. Similarly, p185 HER2 expression was dramatically down-regulated when FAS gene expression was silenced by using the highly sequencespecific mechanism of RNA interference (RNAi). Pharmacological and RNAi-mediated silencing of FAS specifically down-regulated HER2 mRNA and, concomitantly, caused a prominent up-regulation of PEA3, a transcriptional repressor of HER2. A cytoplasmic redistribution of p185 HER2 was associated with marked morphological changes of FAS RNAi-transfected cells, whereas chemical inhibitors of FAS promoted a striking nuclear accumulation of p185 HER2 . The simultaneous targeting of FAS and HER2 by chemical FAS inhibitors and the humanized antibody directed against p185 HER2 trastuzumab, respectively, was synergistically cytotoxic toward HER2 overexpressors. Similarly, concurrent RNAi-mediated silencing of FAS and HER2 genes synergistically stimulated apoptotic cell death in HER2 overexpressors. p185 HER2 was synergistically down-regulated after simultaneous inhibition of FAS and HER2 by either pharmacological inhibitors or small interfering RNA. These findings provide evidence of an active role of FAS in cancer evolution by specifically regulating oncogenic proteins closely related to malignant transformation, strongly suggesting that HER2 oncogene may act as the key molecular sensor of energy imbalance after the perturbation of tumor-associated FAS hyperactivity in cancer cells.trastuzumab ͉ small interfereing RNA ͉ chemotherapy ͉ lipogenesis ͉ Herceptin T he biosynthetic enzyme fatty acid synthase (FAS) is the major enzyme required for the anabolic conversion of dietary carbohydrates to fatty acids, and it functions normally in cells with high lipid metabolism. Under normal physiological conditions, any FAS increase is tightly regulated by a number of environmental, hormonal, and nutritional signals (1, 2). However, human tissue studies have demonstrated that infiltrating carcinomas of the breast constitutively express high levels of FAS compared to nontransformed human epithelial tissue (3-8). Furthermore, increased levels of FAS accompany the development of in situ carcinoma of the breast, suggesting a potential link between increased expression and increased risk of breast cancer development (9). Remarkably, overexpression and hyperactivity of FAS is associated with more aggressive breast and ovarian cancers (3-8, 10). The early and nearly universal up-regulation of FAS in many human cancers and its association with poor clinical outcome both strengthen the hypothesis that FAS is involved in the development, maintenance, and enhancement of the malignant...

Summary To evaluate the association between haemoglobinuria and chronic kidney disease (CKD) in sickle cell anaemia (SCA), we analysed 356 adult haemoglobin SS or Sβ° thalassaemia patients from the University of Illinois at Chicago (UIC) and 439 from the multi-centre Walk-Treatment of Pulmonary Hypertension and Sickle Cell Disease with Sildenafil Therapy (PHaSST) cohort. CKD was classified according to National Kidney Foundation Kidney Disease Outcomes Quality Initiatives guidelines. Haemoglobinuria, defined as positive haem on urine dipstick with absent red blood cells on microscopy, was confirmed by enzyme-linked immunosorbent assay in a subset of patients. The prevalence of CKD was 58% in the UIC cohort and 54% in the Walk-PHaSST cohort, and haemoglobinuria was observed in 36% and 20% of the patients, respectively. Pathway analysis in both cohorts indicated an independent association of lactate dehydrogenase with haemoglobinuria and, in turn, independent associations of haemoglobinuria and age with CKD (P<0.0001). After a median of 32 months of follow-up in the UIC cohort, haemoglobinuria was associated with progression of CKD (halving of estimated glomerular filtration rate or requirement for dialysis; Hazard ratio [HR] 13.9, 95% confidence interval [CI] 1.7-113.2, P=0.0012) and increasing albuminuria (HR 3.1, 95% CI: 1.3-7.7; logrank P=0.0035). In conclusion haemoglobinuria is common in SCA and is associated with CKD, consistent with a role for intravascular haemolysis in the pathogenesis of renal dysfunction in SCA.

Overexpression of the lipogenic enzyme fatty acid synthase (FAS) is a common molecular feature in subsets of sex-steroid-related tumors including endometrium and breast carcinomas that are associated with poor prognosis. Pharmacological inhibition of tumor-associated FAS hyperactivity is under investigation as a chemotherapeutic target. We examined the effects of the mycotoxin cerulenin (a covalent FAS inactivator), and the novel small compound C75 (a slow-binding FAS inhibitor) on estradiol (E 2 )-and tamoxifen (TAM)-stimulated ERdriven molecular responses in Ishikawa cells, an in vitro model of well-differentiated human endometrial carcinoma. We evaluated the effects of FAS inhibition on E 2 -and TAM-induced estrogen receptor (ER) transcriptional activity by using transient cotransfection assays with an estrogen-response element reporter construct (ERE-Luciferase). Antiestrogenic effects of cerulenin and C75 were observed by dose-dependent inhibition of E 2 -stimulated ERE-dependent transcription, whereas FAS inhibitors did not significantly increase the levels of ERE transcriptional activity in the absence of E 2 . Moreover, pharmacological blockade of FAS activity completely abolished TAMstimulated ERE activity. To address the reliability of transient transfection assays, the effects of FAS inhibitors on E 2 -inducible gene products were evaluated. FAS blockade induced a dose-dependent decrease in E 2 -inducible alkaline phosphatase activity. E 2 -stimulated accumulation of progesterone receptor (PR) and HER-2/neu oncogene was abolished in the presence of FAS blockers. FAS inhibition also resulted in a marked downregulation of E 2 -stimulated ERa expression, and noticeably impaired E 2 -induced ERa nuclear accumulation. A dose-dependent decrease in cell proliferation and cell viability was observed after FAS blockade. A Cell Death ELISA, detecting DNA fragmentation, demonstrated that FAS inhibitors stimulated apoptosis of Ishikawa cells. The analysis of critical E 2 -and TAMrelated cell cycle proteins revealed an increase of both the expression and the nuclear accumulation of cyclindependent kinase inhibitors p21 WAF1/CIP1 and p27 Kip1 following FAS inhibition. To rule out non-FAS ceruleninand C75-related effects, we finally monitored ER signaling after silencing of FAS gene expression using the highly sequence-specific mechanism of RNA interference (RNAi).

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