Insulin resistance is common in individuals with obesity or type 2 diabetes (T2D), in which circulating insulin levels are frequently increased. Recent epidemiological and clinical evidence points to a link between insulin resistance and cancer. The mechanisms for this association are unknown, but hyperinsulinaemia (a hallmark of insulin resistance) and the increase in bioavailable insulin-like growth factor I (IGF-I) appear to have a role in tumor initiation and progression in insulin-resistant patients. Insulin and IGF-I inhibit the hepatic synthesis of sex-hormone binding globulin (SHBG), whereas both hormones stimulate the ovarian synthesis of sex steroids, whose effects, in breast epithelium and endometrium, can promote cellular proliferation and inhibit apoptosis. Furthermore, an increased risk of cancer among insulin-resistant patients can be due to overproduction of reactive oxygen species (ROS) that can damage DNA contributing to mutagenesis and carcinogenesis. On the other hand, it is possible that the abundance of inflammatory cells in adipose tissue of obese and diabetic patients may promote systemic inflammation which can result in a protumorigenic environment. Here, we summarize recent progress on insulin resistance and cancer, focusing on various implicated mechanisms that have been described recently, and discuss how these mechanisms may contribute to cancer initiation and progression.

Objective: We aimed at evaluating whether the addition of low-dose metformin to dietary treatment could be an effective approach in nondiabetic patients with nonalcoholic fatty liver disease (NAFLD). Methods: We carried out a 6-month prospective study in a series of overweight or obese patients with ultrasonographic diagnosis of hepatic steatosis. In total, 50 patients were enrolled and randomized into two groups: the first group (n ¼ 25) was given metformin (1 g per day) plus dietary treatment and the second group (n ¼ 25) was given dietary treatment alone. Results: At the end of the study, the proportion of patients with echographic evidence of fatty liver was reduced in both the metformin (Po0.0001) and the diet group (P ¼ 0.029). Moreover, patient body mass index and waist circumference significantly decreased in both groups (Po0.001). Fasting glucose, insulin resistance (evaluated as homeostasis model assessment of insulin resistance (HOMA-IR)) and serum adiponectin decreased in both groups, although these changes reached statistical significance only in the metformin group. In this group, HOMA-IR decreased from 3.3±1.6 to 2.4±1.2 (P ¼ 0.003), whereas it decreased from 3.2 ± 1.6 to 2.8 ± 1.1 (not significant, NS) in the diet group. Similarly, the proportion of patients with impaired fasting glucose declined from 35 to 5% (P ¼ 0.04) in the metformin and from 32 to 12% (NS) in the diet group. At baseline, B40% of patients in both groups met the diagnostic criteria of metabolic syndrome. This proportion decreased to 20% in the metformin group (P ¼ 0.008) and to 32% in the diet group (NS). Conclusions: In our 6-month prospective study, both low-dose metformin and dietary treatment alone ameliorated liver steatosis and metabolic derangements in patients with NAFLD. However, metformin was more effective than dietary treatment alone in normalizing several metabolic parameters in these patients.

SummaryWhile pathways for N-glycosylation in Eukarya and Bacteria have been solved, considerably less is known of this post-translational modification in Archaea. In the halophilic archaeon Haloferax volcanii, proteins encoded by the agl genes are involved in the assembly and attachment of a pentasaccharide to select asparagine residues of the S-layer glycoprotein. AglP, originally identified based on the proximity of its encoding gene to other agl genes whose products were shown to participate in N-glycosylation, was proposed, based on sequence homology, to serve as a methyltransferase. In the present report, gene deletion and mass spectrometry were employed to reveal that AglP is responsible for adding a 14 Da moiety to a hexuronic acid found at position four of the pentasaccharide decorating the Hfx. volcanii S-layer glycoprotein. Subsequent purification of a tagged version of AglP and development of an in vitro assay to test the function of the protein confirmed that AglP is a S-adenosyl-L-methioninedependent methyltransferase.

Short-term NSAID treatment improves the patient disease-specific quality of life with a parallel decrease in pro-inflammatory synovial fluid cytokine levels in knee OA. Signal transduction pathways may be involved in regulating the anti-inflammatory effects of NSAIDs. ClinicalTrial.gov: NCT01860833.

Like the Eukarya and Bacteria, the Archaea also perform N glycosylation. Using the haloarchaeon Haloferax volcanii as a model system, a series of Agl proteins involved in the archaeal version of this posttranslational modification has been identified. In the present study, the participation of HVO_1517 in N glycosylation was considered, given its homology to a known component of the eukaryal N-glycosylation pathway and because of the genomic proximity of HVO_1517 to agl genes encoding known elements of the H. volcanii N-glycosylation process. By combining the deletion of HVO_1517 with mass spectrometric analysis of both dolichol phosphate monosaccharide-charged carriers and the S-layer glycoprotein, evidence was obtained showing the participation of HVO_1517, renamed AglJ, in adding the first hexose of the N-linked pentasaccharide decorating this reporter glycoprotein. The deletion of aglJ, however, did not fully prevent the attachment of a hexose residue to the S-layer glycoprotein. Moreover, in the absence of AglJ, the level of only one of the three monosaccharide-charged dolichol phosphate carriers detected in the cell was reduced. Nonetheless, in cells lacking AglJ, no further sugar subunits were added to the remaining monosaccharide-charged dolichol phosphate carriers or to the monosaccharide-modified S-layer glycoprotein, pointing to the importance of the sugar added through the actions of AglJ for proper N glycosylation. Finally, while aglJ can be deleted, H. volcanii surface layer integrity is compromised in the absence of the encoded protein.N glycosylation is a posttranslational modification of proteins in all three domains of life. However, in contrast to our relatively advanced description of the eukaryal and bacterial N-glycosylation pathways (12, 24, 26), many questions regarding the parallel process in the Archaea remain. With the identification of a series of agl (archaeal glycosylation) genes in the haloarchaeon Haloferax volcanii and the methanogens Methanococcus voltae and Methanococcus maripaludis, some insight into archaeal N glycosylation is, however, available (for a review, see references 6 and 28). For H. volcanii, AglB, AglD, AglE, AglF, AglG, AglI, AglM, and AglP were shown to participate in the assembly and attachment of a pentasaccharide to select Asn residues of the surface (S)-layer protein, a reporter of N glycosylation in this species (23). Specifically, AglG, AglI, AglE, and AglD are thought to be glycosyltransferases involved in adding the second, third, fourth, and fifth pentasaccharide subunits (2, 3, 29), respectively; AglF is a glucose-1-phosphate uridyltransferase (30); AglM is a UDP-glucose dehydrogenase (30); AglP is an S-adenosyl-L-methionine-dependent methyltransferase (17); and AglB is the oligosaccharyltransferase (2).Despite these advances, proteins catalyzing several central steps in the H. volcanii N-glycosylation pathway have yet to be described. Accordingly, one such candidate, HVO_1517, encoding one of the five previously identified H. volcanii homologues of eu...