The Cesare Maltoni Cancer Research Center of the European Ramazzini Foundation has conducted a long-term bioassay on aspartame (APM), a widely used artificial sweetener. APM was administered with feed to 8-week-old Sprague-Dawley rats (100–150/sex/group), at concentrations of 100,000, 50,000, 10,000, 2,000, 400, 80, or 0 ppm. The treatment lasted until natural death, at which time all deceased animals underwent complete necropsy. Histopathologic evaluation of all pathologic lesions and of all organs and tissues collected was routinely performed on each animal of all experimental groups. The results of the study show for the first time that APM, in our experimental conditions, causes a) an increased incidence of malignant-tumor–bearing animals with a positive significant trend in males (p ≤ 0.05) and in females (p ≤ 0.01), in particular those females treated at 50,000 ppm (p ≤ 0.01); b) an increase in lymphomas and leukemias with a positive significant trend in both males (p ≤ 0.05) and females (p ≤ 0.01), in particular in females treated at doses of 100,000 (p ≤ 0.01), 50,000 (p ≤ 0.01), 10,000 (p ≤ 0.05), 2,000 (p ≤ 0.05), or 400 ppm (p ≤ 0.01); c) a statistically significant increased incidence, with a positive significant trend (p ≤ 0.01), of transitional cell carcinomas of the renal pelvis and ureter and their precursors (dysplasias) in females treated at 100,000 (p ≤ 0.01), 50,000 (p ≤ 0.01), 10,000 (p ≤ 0.01), 2,000 (p ≤ 0.05), or 400 ppm (p ≤ 0.05); and d) an increased incidence of malignant schwannomas of peripheral nerves with a positive trend (p ≤ 0.05) in males. The results of this mega-experiment indicate that APM is a multipotential carcinogenic agent, even at a daily dose of 20 mg/kg body weight, much less than the current acceptable daily intake. On the basis of these results, a reevaluation of the present guidelines on the use and consumption of APM is urgent and cannot be delayed.

Although diabetes results in part from a deficiency of normal pancreatic beta cells, inducing human beta cells to regenerate is difficult. Reasoning that insulinomas hold the “genomic recipe” for beta cell expansion, we surveyed 38 human insulinomas to obtain insights into therapeutic pathways for beta cell regeneration. An integrative analysis of whole-exome and RNA-sequencing data was employed to extensively characterize the genomic and molecular landscape of insulinomas relative to normal beta cells. Here, we show at the pathway level that the majority of the insulinomas display mutations, copy number variants and/or dysregulation of epigenetic modifying genes, most prominently in the polycomb and trithorax families. Importantly, these processes are coupled to co-expression network modules associated with cell proliferation, revealing candidates for inducing beta cell regeneration. Validation of key computational predictions supports the concept that understanding the molecular complexity of insulinoma may be a valuable approach to diabetes drug discovery.

Genomic imprinting refers to silencing of one parental allele in the zygotes of gametes depending upon the parent of origin. Loss of imprinting (LOI) is the gain of function from the silent allele that can have a maximum effect of doubling the gene dosage. LOI may play a significant role in the etiology of intrauterine growth restriction (IUGR). Using placental tissue from ten normal and seven IUGR pregnancies, we conducted a systematic survey of the expression of a panel of 74 "putatively" imprinted genes using quantitative RT-PCR. We found that 52/74 (~70%) of the genes were expressed in human placentas. Nine of the 52 (17%) expressed genes were significantly differentially expressed between normal and IUGR placentas; five were upregulated (PHLDA2, ILK2, NNAT, CCDC86, PEG10) and four downregulated (PLAGL1, DHCR24, ZNF331, CDKAL1). We also assessed LOI profile of 14 imprinted genes in 14 normal and 24 IUGR placentas using a functional and sensitive assay developed in our laboratory. Little LOI was observed in any placentas for five of the genes (PEG10, PHLDA2, MEG3, EPS15, CD44). With the 149 heterozygosities examined, 40 (26.8%) exhibited LOI >3%. Some genes exhibited frequent LOI in placentas regardless of the disease status (IGF2, TP73, MEST, SLC22A18, PEG3), while others exhibited LOI only in IUGR placentas (PLAGL1, DLK1, H19, SNRPN). Importantly, there was no correlation between gene expression and LOI profile. Our study suggests that genomic imprinting may play a role in IUGR pathogenesis, but mechanisms other than LOI may contribute to dysregulation of imprinted genes. IntroductionGenomic imprinting refers to silencing of one parental allele in the zygotes of gametes depending upon the parent of origin; this silencing occurs via epigenetic processes such as DNA methylation and/or histone modification. 1 It has been hypothesized in the "parental conflict" theory that paternally expressed genes favors the utilization of maternal resources for the benefit of the offspring while the maternally expressed genes act to preserve such resources. Thus, imprinted genes that are paternally expressed (maternally imprinted) are predicted to promote growth of the offspring, either in utero or in perinatal period, whilst maternally expressed (paternally imprinted) genes would act as growth suppressors to assure appropriate allocation of limited maternal resources to each conceptus. 2 Consequently, imprinted genes play critical roles in regulation of growth and development; disruption of this critical process, such as loss of imprinting (LOI), has been associated with a wide range of human diseases including birth defects neurodevelopmental disorders and cancer. [3][4][5][6][7] Compared to other mammalian genomes such as that of the mouse, the human genome is imprinted to a much lesser degree, possibly due to a lack of competition for maternal resources because human pregnancies are typically singletons. 8 The estimated number of imprinted genes is ~100-200 (<1% of the genome). This limited number of imprinted genes affo...

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