Carlotta Lunghi

Stable GM3 lactone mimetic raises antibodies specific for the antigens expressed on melanoma cells.

Immunotherapy of tumors and of melanoma in particular has a long history, and recently this therapeutic approach found a reliable scientific rationale. This biological therapy aims to teach the patients immune system to recognize the antigens expressed on tumor cells and destroy them, leaving normal cells intact. The success of this therapy highly depends on the selection of target antigens that are essential for tumors growth and progression. The overexpression of GM(3) ganglioside 1 and especially the expression of its metabolite GM(3) lactone 2 characterize murine and human melanomas, playing an important role in tumor progression and making such self-antigens potential targets for the immunotherapy of these neoplasms. Although more immunogenic than its precursor, GM(3) lactone 2 is unsuitable to be used in immunotherapy as a melanoma-associated antigen (MAA) because it is unstable under physiological conditions. We designed and synthesized the hydrolytically stable mimetic 3, which is remarkably simpler than the native lactone 2; after conjugation of 3 to the protein carrier keyhole-limpet hemocyanin (KLH), the obtained glycoprotein 5 was used as the immunogen in vivo to successfully elicit specific antimelanoma antibodies. In fact, no appreciable binding to GM(1) was observed. Capitalizing on the stability and on the reduced structural complexity of mimetic 3, the immunostimulant 5 we report represents a new promising synthetic glycoconjugate for the immunotherapy of melanoma.

Synthesis, Conformational Studies, Binding Assessment and Liposome Insertion of a Thioether-Bridged Mimetic of the Antigen GM3-Ganglioside Lactone.

Oncogenic transformations are often associated with abnormal glycosylation in human tumours. In recent years a variety of monoclonal antibodies have been developed to specifically recognize carbohydrate epitopes that result from these faulty glycosylation processes. These epitopes, known as tumourassociated antigens (TAAs), have been successfully used as markers of tumour progression, and include catbohyrates expressed on normal tissues, but which are accumulated in high density on the surface of tumour cells. GM3 Ganglioside, a glycosphingolipid found in essentially all types of cells and tissues, is over expressed in melanoma cells with metastatic potential. The corresponding GM3 lactone (1a, Scheme 1) has also been found in melanoma as a minor component; its formation is likely promoted by the lower pH environment of tumour cells and, possibly, by a different conformation of GM3 ganglioside induced on the tumour cell surface as a result of localised high density. In the development of a biological therapy for tumours, GM3 ganglioside and GM3 lactone 1a have been extensively investigated as potential vaccines against cancer. Immunization experiments have indicated that GM3 lactone is more immunogenic than GM3 itself ; however, under physiological conditions, the equilibrium amount of lactone is below the recognition threshold. In addition, GM3 lactone 1a and its analogue 1b are both potent inducers of antimelanoma cytotoxic T cell (CTL) response. These data suggest that the antigenic ACHTUNGTRENNUNGdeterminant of 1a might not include the acetamido function, and that the folded shape, which is characteristic of a lactone ring-containing structure, might be responsible for the enhanced immunogenicity of 1a compared to GM3 ganglioACHTUNGTRENNUNGside. A few years ago two hydrolytically stable analogues of GM3 lactone, namely a GM3 lactam and a GM3 ether, were prepared but they have to date not been used for anticancer therapy. The development of mimetics of 1a that are resistant to hydrolysis remains a challenging target in the immunotherapy domain. Here, we report the conformational analysis and synthesis of the spiro glycoside 2 (Scheme 1), a thioether-bridged Figure 1. Three-dimensional plot of the preferred conformations of compounds 1a and 2 separately and superimposed; the hydrogen atoms are omitted in the superposition for clarity.

Structural study of liposomes loaded with a GM3 lactone analogue for the targeting of tumor epitopes

Therapeutic vaccination with tumor antigens is a new approach in cancer treatment, which aims at inducing immune response while avoiding the side effects generally associated to many conventional therapies. To improve the efficacy of vaccines, suitable carriers may be used. Herein the insertion of a thioether analogue of GM3 lactone (SNeuAC-C14) into liposomes is reported. SNeuAC-C14 is a potential vaccine for the targeting of saccharide-based tumor epitopes. Different liposome formulations were designed to act as carriers and to generate recognition by tumor epitopes. The structural study of pure and loaded liposomes was carried out by synchrotron Small Angle X-ray Scattering and was complemented by Dynamic Light Scattering and Zeta potential measurements. This provided detailed information on relevant properties of the investigated host-guest structures and showed that the active unit of SNeuAC-C14, i.e. its spiro tricyclic moiety, was located in the polar head region of the liposome bilayer, which is an important requirement for recognition phenomena. Moreover, it was found that most of the SNeuAC-C14/liposome complexes were positively charged. The obtained results allow these systems to be considered as candidates to promote immunoresponse in tumor cells.

Stereoselective Synthesis of 1,3-Disaccharides through Diels-Alder Reactions: Part 2[ 1 ]: Convenient Protecting Groups for Heterodienes and Conformational Evaluations

Improved synthesis of 1,3-disaccharides, obtained diastereomerically pure by [4+2] hetero cycloadditions between glycals and α -thiono-β -keto-δ -lactones, has been reported. The choice of appropriate protecting groups for β -keto-δ -lactones, stable under cycloaddition conditions employed, sensibly shortened the synthesis of heterodienic precursors. The first example of a β -oxy-imino-δ -lactone synthesized from β -keto-δ -lactones was also reported. Molecular modeling and conformational evaluations about the cycloaddition features allowed tentatively rationalizing the experimental results.

Factors associated with antidiabetic medication non-adherence in patients with incident comorbid depression

AIM To identify factors associated with antidiabetic drug (AD) non-adherence among patients with type 2 diabetes and depression. STUDY DESIGN AND SETTINGS We conducted a population-based retrospective cohort study among new AD users with a diagnosis of depression following AD initiation. We used public health insurance data from Quebec. The dependent variable was non-adherence (i.e., <90% of days covered by ≥1AD) in the year after a depression diagnosis. Different sociodemographic, clinical and medication-related variables were assessed as potential factors of non-adherence to AD treatment. We performed univariate and multivariate logistic regressions. RESULTS We identified 3106 new users of ADs with a diagnosis of depression between 2000 and 2006. Of these individuals, 52% were considered non-adherent to their ADs. Baseline non-adherence, younger age, the addition of another AD to the initial treatment, <4 drug claims, visits with several different physicians, high socioeconomic status, and a small number of diabetes complications were associated with AD non-adherence. CONCLUSIONS The factors identified in the present study may help clinicians recognize patients with type 2 diabetes and incident depression at increased risk for non-adherence. In these patients, close follow-up and targeted interventions could help improve adherence to AD treatment, improve glycemic control and reduce complications.

Incidence of Depression and Associated Factors in Patients With Type 2 Diabetes in Quebec, Canada: A Population-Based Cohort Study.

AbstractIt has been reported that the risk of depression is higher among people with type 2 diabetes compared with a nondiabetic population. Among diabetic patients, depression has been associated with worse self-care behaviors, poor glycemic control, and an increased risk of diabetes complications. Identifying factors associated with the occurrence of depression may help physicians identify earlier diabetic patients at a high risk of developing depression, improve prevention, and accelerate proper treatment. To our knowledge, very few population-based studies have reported on the incidence of clinically diagnosed depression as a consequence of type 2 diabetes over a long follow-up period. The objective of this study was to estimate the incidence of clinically diagnosed depression among type 2 diabetic patients newly treated with oral antidiabetic drugs (ADs) and to identify factors associated with the occurrence of depression.Administrative claims data from the public health insurance plan were used to identify a cohort of new oral AD users aged ≥18 years between 2000 and 2006. Patients were followed from oral AD treatment initiation until the diagnosis of depression, ineligibility for the public drug plan, death, or the end of the study, whichever came first. Incidence rates were determined using person-time analysis. Factors associated with depression were identified using multivariable Cox regression analysis.We identified 114,366 new oral AD users, of which 4808 had a diagnosis of depression. The overall incidence rate of depression was 9.47/1000 person-years (PYs) (10.72/1000 PYs for women and 8.27/1000 PYs for men). The incidence of depression was higher during the year after oral AD treatment initiation. Independent factors associated with depression included having had mental disorders other than depression, hospitalization, a higher number of different drugs taken and of physicians visited during the year before oral AD initiation. Moreover, we observed a statistically significant age-by-socioeconomic status interaction.The incidence of diagnosed depression is higher during the first year after oral AD treatment initiation. Clinicians could pay particular attention to women, patients starting an AD at a young age, those with a low socioeconomic status, and especially those with a history of anxiety or dementia.

The Association between Depression and Medication Nonpersistence in New Users of Antidiabetic Drugs

OBJECTIVES To measure the association between depression and nonpersistence with antidiabetic drugs (ADs) among new users of oral ADs and to estimate factors associated with nonpersistence among these new users with depression. METHODS We used administrative claims data to identify an adult cohort (≥18 years) of new oral AD users who were free of depression. We followed the patients from AD initiation until either discontinuation, ineligibility for the public drug plan, death, or the end of the study. A proportional hazard Cox regression model with depression as a time-dependent variable was used to compute the adjusted hazard ratio of nonpersistence. A proportional hazard Cox regression model was also used to identify factors associated with nonpersistence in the subcohort of patients with depression. RESULTS We identified 114,366 new oral AD users, of whom 4,808 were diagnosed with depression during the follow-up. A greater proportion (55.4%) of patients with depression (vs. 42.5% without depression) discontinued their treatment during the follow-up. The adjusted hazard ratio of nonpersistence with ADs was 1.52 (95% confidence interval 1.41-1.63). Among patients with depression, independent factors associated with nonpersistence included younger age at oral AD initiation (<45 years) and starting treatment with drugs other than metformin (especially polytherapy with insulin). CONCLUSIONS Patients with depression are more likely to discontinue their treatment. Health care professionals should pay attention to patients on AD therapy who also suffer from depression, especially if the patients are young or are using insulin because these patients are at an increased risk of nonpersistence.

Early career researchers’ perspectives and roles in patient-oriented research

Plain English summaryPatient-oriented research (POR) has received increasing attention in recent years. In this approach, patients’ experiential knowledge, derived from their experiences of living with a condition or illness and of interacting with the healthcare system, is recognized, valued, and seen as complementary to scientific knowledge. Early career researchers (ECRs) are the next generation of researchers, but little is known about how they perceive POR. In this study, ECRs were invited to reflect on what POR is, how patients can best contribute to research, and ECRs’ own role in developing POR. Using a technique designed to collect expert opinions and find consensus—the Delphi method—a panel of 16 ECRs responded, in three rounds, to three questionnaires, with the second and third being built on responses to the preceding ones. Based on their understanding, the panelists agreed that the most important element in defining POR would be valuing, mobilizing, and legitimizing the experiential knowledge of patients who live with a particular health condition. Panelists considered patients to be integral members of the research team, but were less convinced that they should be considered co-researchers. The panelists saw themselves as taking part in developing POR by sharing information, teaching, and encouraging POR among their peers, as well as by participating actively in organizations interested in POR. This is the first study to examine the perspectives of ECRs, who, along with many others, have an important role in supporting the on-going development of POR so that it becomes more widely adopted.AbstractBackground Literature on patient-oriented research (POR) is growing rapidly. This field is increasingly encouraged by funders and structured by new research networks. POR involves moving away from considering patients as ‘subjects’, towards perceiving them as experts with experience-based knowledge. However, little is known about how early-career researchers (ECRs) perceive POR and their roles in developing it. This study examined how ECRs perceive POR, patients’ roles, the future of POR, and their own role in developing this approach. Methods A three-round Delphi study was conducted with Quebec’s Strategy for People and Patient-Oriented Research and Trials (SUPPORT) Unit awardees, composed of graduate students and clinicians, all ECRs. Of the 25 invited, 18 agreed to participate (72%), with a three-round retention rate of 89% (n = 16 on 18). Panelists answered open-ended questions, selected the most salient statements, and rated their (dis)agreement with proposals using a 7-point scale. Results Five main themes emerged: 1) ECRs’ knowledge of and experience with POR; 2) the POR definition; 3) patients’ roles and contributions; 4) the future of POR; and 5) ECRs’ roles in POR development. This study revealed that the ECRs were not so familiar with POR, even given their opportunities for networking within a scholarship program. Panelists agreed on the main components of a POR definition: valuing, mobilizing, and legitimizing the experiential knowledge of patients living with a health condition; conducting research that focuses on patients’ concerns, participation, and outcomes; and integrating active partnership among a variety of actors. Panelists considered patients to be integral members of the research team (M = 5.31 ± 1.66), but were less convinced they should be considered co-researchers (M = 4.50 ± 1.75). Panelists saw themselves as playing many roles in developing POR, such as becoming well-informed about it and acting as knowledge brokers, motivators, doers, delegators, and activists. Conclusion The ECRs’ perspectives are informative on how the next generation of researchers envision POR, its future and how they might contribute to developing this approach. There is a clear need for a coherent and concerted strategy for POR capacity development, in which ECRs’ perspectives and their specific needs are taken into account.

The impact of incident depression on medication adherence in patients with type 2 diabetes

BACKGROUND Depression has been correlated with suboptimal adherence to antidiabetic drugs (ADs). Most studies on this topic were cross-sectional; thus, the directionality of this relationship could not be established. The objective of this study was to measure the association between incident depression and AD nonadherence among newly treated patients with diabetes. METHODS We performed a population-based cohort study among new AD users using the Quebec public health insurance data. To avoid immortal time bias, we carried out depression diagnosis-time distribution matching by assigning a date of depression diagnosis to individuals without depression. Nonadherence (i.e.,<90% of days covered by≥1 AD) during the year following depression diagnosis (real or assigned date) was the outcome. Multivariate logistic regression analyses that adjusted for baseline adherence and other confounders were used to estimate the adjusted effect of depression on AD nonadherence. RESULTS Between 2000 and 2006, we identified 3,106 new AD users with a subsequent diagnosis of depression and 70,633 without depression, of which 52% and 49% became non-adherent to AD treatment, respectively. Among patients with depression, 52.0% were considered AD non-adherent in the year after depression diagnosis compared with 49.0% of matched patients without depression. Depression was associated with AD nonadherence after accounting for baseline adherence and other confounders with an adjusted odds ratio of 1.24 (95% confidence interval: 1.13-1.37). CONCLUSIONS The results suggest that depression is an independent risk factor for AD nonadherence. Patients with type 2 diabetes and depression might benefit from adherence-enhancing interventions.