The value of FATS expression in predicting sensitivity to radiotherapy in breast cancer

Purpose

The fragile-site associated tumor suppressor (FATS) is a newly identified tumor suppressor involved in radiation-induced tumorigenesis. The purpose of this study was to characterize FATS expression in breast cancers about radiotherapy benefit, patient characteristics, and prognosis.

Results

The expression of FATS mRNA was silent or downregulated in 95.2% of breast cancer samples compared with paired normal controls (P < .0001). Negative status of FATS was correlated with higher nuclear grade (P = .01) and shorter disease-free survival (DFS) of breast cancer (P = .036). In a multivariate analysis, FATS expression showed favorable prognostic value for DFS (odds ratio, 0.532; 95% confidence interval, 0.299 to 0.947; (P = .032). Furthermore, improved survival time was seen in FATS-positive patients receiving radiotherapy (P = .006). The results of multivariate analysis revealed independent prognostic value of FATS expression in predicting longer DFS (odds ratio, 0.377; 95% confidence interval, 0.176 to 0.809; P = 0.012) for patients receiving adjuvant radiotherapy. In support of this, reduction of FATS expression in breast cancer cell lines, FATS positive group significantly sensitized than Knock-down of FATS group.

Materials and Methods

Tissue samples from 156 breast cancer patients and 42 controls in tumor bank were studied. FATS gene expression was evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR). FATS function was examined in breast cancer cell lines using siRNA knock-downs and colony forming assays after irradiation.

Conclusions

FATS status is a biomarker in breast cancer to identify individuals likely to benefit from radiotherapy.

The high-fat high-fructose hamster as an animal model for niacin's biological activities in humans

OBJECTIVE

Niacin has been used for more than 50 years to treat dyslipidemia, yet the mechanisms underlying its lipid-modifying effects remain unknown, a situation stemming at least in part from a lack of validated animal models. The objective of this study was to determine if the dyslipidemic hamster could serve as such a model.

MATERIALS/METHODS

Dyslipidemia was induced in Golden Syrian hamsters by feeding them a high-fat, high-cholesterol, and high-fructose (HF/HF) diet. The effect of high-dose niacin treatment for 18 days and 28 days on plasma lipid levels and gene expression was measured.

RESULTS

Niacin treatment produced significant decreases in plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and free fatty acids (FFA), but had no measureable effect on high-density lipoprotein cholesterol (HDL-C) in the dyslipidemic hamster. Niacin treatment also produced significant increases in hepatic adenosine ATP-Binding Cassette A1 (ABCA1) mRNA, ABCA1 protein, apolipoprotein A-I (Apo A-I) mRNA, and adipose adiponectin mRNA in these animals.

CONCLUSIONS

With the exception of HDL-C, the lipid effects of niacin treatment in the dyslipidemic hamster closely parallel those observed in humans. Moreover, the effects of niacin treatment on gene expression of hepatic proteins related to HDL metabolism are similar to those observed in human cells in culture. The HF/HF-fed hamster could therefore serve as an animal model for niacin's lowering of proatherogenic lipids and mechanisms of action relative to lipid metabolism.

Common fragile sites: genomic hotspots of DNA damage and carcinogenesis

Genomic instability, a hallmark of cancer, occurs preferentially at specific genomic regions known as common fragile sites (CFSs). CFSs are evolutionarily conserved and late replicating regions with AT-rich sequences, and CFS instability is correlated with cancer. In the last decade, much progress has been made toward understanding the mechanisms of chromosomal instability at CFSs. However, despite tremendous efforts, identifying a cancer-associated CFS gene (CACG) remains a challenge and little is known about the function of CACGs at most CFS loci. Recent studies of FATS (for Fragile-site Associated Tumor Suppressor), a new CACG at FRA10F, reveal an active role of this CACG in regulating DNA damage checkpoints and suppressing tumorigenesis. The identification of FATS may inspire more discoveries of other uncharacterized CACGs. Further elucidation of the biological functions and clinical significance of CACGs may be exploited for cancer biomarkers and therapeutic benefits.

Effects of saturated and unsaturated fat feeding on experimental thromboatherosclerosis

Intra-aortic insertion of magnesium-aluminum-zinc wire was used to induce experimental aortic thrombosclerosis in rabbits fed kennel chow and in rabbits fed chow supplemented with cholesterol, with and without additions of saturated or unsaturated fat. In the absence of cholesterol supplement, no spontaneous atherosclerosis developed and no excess lipid appeared in the thrombosclerotic plaque, regardless of supplementations with saturated or unsaturated fat. In the presence of cholesterol supplement, both spontaneous atherosclerosis and thromboatherosclerosis were noted. Additional supplementations with saturated or unsaturated fat did not ameliorate either lesion. Rabbits ingesting cholesterol plus unsaturated fat exhibited no less hypercholesteremia, spontaneous atherosclerosis, and thromboatherosclerosis than did rabbits on any other regimen. The results are discussed with reference to the effect of oral unsaturated fat on bile acid and cholesterol within the intestinal lumen.

Erythrocyte sedimentation rate and blood viscosity as modified by fat emulsions

The effect of lecithin and lecithin-free intravenous fat emulsions on erythrocyte sedimentation and blood viscosity was investigated. Lecithin-emulsified cottonseed oil markedly depressed erythrocyte sedimentation and increased blood viscosity of human and dog blood. This effect was only temporary and the erythrocyte sedimentation rate returned to normal within 24 hours as determined by an in vivo study with dogs. The erythrocyte sedimentation rate of human and dog erythrocytes incubated in cottonseed oil emulsified with polyethylene glycol stearate, more closely resembled that of whole blood. Blood viscosity decreased in the presence of this emulsifier. It is conclude that the influence of lipemia on erythrocyte sedimentation and blood viscosity is due to the emulsifier rather than the oil component of the chylomicron.

EFFECT IN THE COW OF INTRARUMINAL INFUSIONS OF VOLATILE FATTY ACIDS AND OF LACTIC ACID ON THE SECRETION OF THE COMPONENT FATTY ACIDS OF THE MILK FAT AND ON THE COMPOSITION OF BLOOD

1. The effects in the cow of intraruminal infusions of acetic acid, propionic acid or butyric acid on the secretion of the component fatty acids of the milk fat, and of these acids and of lactic acid on the composition of the blood plasma of the jugular vein, have been studied. 2. The infusion of acetic acid or butyric acid increased the yield of the C(4)-C(16) acids of milk fat but decreased the yield of C(18) acids. The infusion of propionic acid decreased the yields of all major component acids except palmitic acid and possibly lauric acid. 3. The changes in the concentrations in blood plasma of glucose and of ketone bodies were consistent with the glucogenic effect of propionic acid and the ketogenic effects of butyric acid and acetic acid. The effects of lactic acid were not consistent from cow to cow. Only with the infusion of acetic acid was a significant increase in the concentration of total volatile fatty acids in blood plasma found. Infusions of butyric acid and of propionic acid tended to depress the concentration of citric acid in the blood plasma and infusion of acetic acid increased it. No consistent effects of the infused acids on the concentration in blood plasma of esterified cholesterol, free cholesterol, triglyceride or phospholipid were observed. 4. The possibility is discussed that the effects of the infused acids on milk-fat secretion are caused through an alteration of the concentrations of precursors of milk fat in mammary arterial blood.

CHARACTERIZATION OF LEPTOSPIRAL LIPASE

Patel, Virendra (University of Missouri, Columbia), Herbert S. Goldberg, and Donald Blenden. Characterization of leptospiral lipase. J. Bacteriol. 88:877-884. 1964.-A technique for leptospiral lipase extraction which yielded a highly active, stable, and concentrated lipase preparation was developed. The chief characteristics of leptospiral lipase were determined and are summarized below. Leptospiral lipase was soluble in water and stable in both the dry state and in aqueous solution. Tributyrin was found to be the substrate upon which the enzyme was most active. With this substrate, leptospiral lipase was found to display optimal activity at pH 7 and at 30 C. The Michaelis constant of leptospiral lipase with tributyrin substrate was determined to be 4.76 x 10(-2)m. The enzyme was not inhibited by low concentrations of mercury, iron, cobalt, or copper or by -SH blocking agents. Bile and calcium chloride in low concentrations were able to increase lipase activity at alkaline pH. The isoelectric point of leptospiral lipase was determined to be in the range of pH 5.2 to 5.4.

CONVULSIVE SYNDROME IN RABBITS INJECTED WITH FAT EMULSION AND HEPARIN

Functionally hepatectomized rabbits showed convulsions and coma within 2 hours after the intravenous injection of fat emulsion and heparin. Intravenous injection of the detergent triton prevented this syndrome, if given before the fat emulsion and heparin, and reversed it if given subsequently. Extremely high plasma non-esterified fatty acid levels were noted in rabbits showing the convulsive syndrome, but not in animals that received the detergent. The mechanism of the convulsions probably includes the toxicity of high amounts of non-esterified fatty acids.

OBSERVATIONS ON THE ANTITHYROID AND GOITROGENIC ACTIVITY OF MILK

Fresh and dried milk samples obtained during 1960–64 have been examined for antithyroid and goitrogenic activity in rats. In acute experiments milk caused a depression in the uptake of 131I. Samples taken during the spring months were most active in this respect. The iodine content of milk was not responsible for this depression. Calcium and fat in the amounts present in milk caused a decrease in uptake of 131I and the calcium content of milk was highest in the spring. In experiments involving feeding fresh or dried milk for 3 months neither thyroid enlargement nor interference with thyroid hormone synthesis was produced regularly though occasional samples caused some minor changes. There was no consistent evidence for goitrogenic activity in milk.