AF1q is a universal marker of neuroblastoma that sustains N-Myc expression and drives tumorigenesis

Neuroblastoma is the most common extracranial malignant tumor of childhood, accounting for 15% of all pediatric cancer deaths. Despite significant advances in our understanding of neuroblastoma biology, five-year survival rates for high-risk disease remain less than 50%, highlighting the importance of identifying novel therapeutic targets to combat the disease. MYCN amplification is the most frequent and predictive molecular aberration correlating with poor outcome in neuroblastoma. N-Myc is a short-lived protein primarily due to its rapid proteasomal degradation, a potentially exploitable vulnerability in neuroblastoma. AF1q is an oncoprotein with established roles in leukemia and solid tumor progression. It is normally expressed in brain and sympathetic neurons and has been postulated to play a part in neural differentiation. However, no role for AF1q in tumors of neural origin has been reported. In this study, we found AF1q to be a universal marker of neuroblastoma tumors. Silencing AF1q in neuroblastoma cells caused proteasomal degradation of N-Myc through Ras/ERK and AKT/GSK3β pathways, activated p53 and blocked cell cycle progression, culminating in cell death via the intrinsic apoptotic pathway. Moreover, silencing AF1q attenuated neuroblastoma tumorigenicity in vivo signifying AF1q's importance in neuroblastoma oncogenesis. Our findings reveal AF1q to be a novel regulator of N-Myc and potential therapeutic target in neuroblastoma.

Correction to: Sphingadienes show therapeutic efficacy in neuroblastoma in vitro and in vivo by targeting the AKT signaling pathway

The authors would like to note an omission of disclosure in this paper. Author JDS is cofounder, equity-holder, and consultant of GILTRx Therapeutics.

Sphingadienes show therapeutic efficacy in neuroblastoma in vitro and in vivo by targeting the AKT signaling pathway

Neuroblastoma is a childhood malignancy that accounts for approximately 15% of childhood cancer deaths. Only 20-35% of children with metastatic neuroblastoma survive with standard therapy. Identification of more effective therapies is essential to improving the outcome of children with high-stage disease. Sphingadienes (SD) are growth-inhibitory sphingolipids found in natural sources including soy. They exhibit chemopreventive activity in mouse models of colon cancer, where they mediate cytotoxicity by inhibiting key pro-carcinogenic signaling pathways. In this study, the effect of SD on neuroblastoma was analyzed. Low micromolar concentrations of SD were cytotoxic to transformed and primary neuroblastoma cells independently of N-Myc amplification status. SD induced both caspase-dependent apoptosis and autophagy in neuroblastoma cells. However, only inhibition of caspase-dependent apoptosis protected neuroblastoma cells from SD-mediated cytotoxicity. SD also inhibited AKT activation in neuroblastoma cells as shown by reduced phosphorylated AKT levels. Pre-treatment with insulin attenuated SD-mediated cytotoxicity in vitro. SD-loaded nanoparticles (NP) administered parenterally to immunodeficient mice carrying neuroblastoma xenografts resulted in cytotoxic levels of SD in the circulation and significantly reduced tumor growth compared to vehicle-treated controls. Analysis of tumor extracts demonstrated reduced AKT activation in tumors of mice treated with SD-NP compared to controls treated with empty NP. Our findings indicate SD are novel potential chemotherapeutic agents that promote neuroblastoma cell death and reduce tumorigenicity in vivo.

Assessing students' professionalism: considering professionalism's diverging definitions

CONTEXT

Although most health education programs assess students' professionalism, there is little clarity within the health education literature on the definition of professionalism. This makes assessment of students' professionalism a potentially flawed activity. This literature review clarifies professionalism by bringing together diverging definitions from across a number of health disciplines and discusses the complexities and limitations of these definitions.

METHODS

A search was conducted within the medical and health science education literature to identify articles that discussed professionalism and its assessment. Theoretical, qualitative and empirical research were included in the review.

FINDINGS

The literature defines professionalism as upholding professional values, as demonstrating professional attitudes or demonstrating professional behaviours. Each of these perspectives influences how professionalism is to be assessed, with each perspective having its own limitations. The behavioural perspective is simple to assess, but it has been criticised for being too superficial. The values perspective has the potential to develop professionals who are motivated by philanthropic values, but values can be difficult to identify and assess. Attitudes are complex in their structure, but they are less superficial than behaviours and can be assessed with attitudinal scales.

CONCLUSION

Health professions educators should ideally assess all three perspectives of professionalism, however, this may not be realistic given the already laden curricula and the demands on educators. Educators may decide to only assess one perspective and given its advantages, the attitudes perspective may be a useful starting point.

Effect of oral zinc supplementation upon Taenia crassiceps murine cysticercosis

The effect of zinc supplementation on Taenia crassiceps murine cysticercosis was studied in susceptible BALB/cAnN mice. Female offspring of mice supplemented with high zinc throughout gestation and lactation were intraperitoneally infected with T. crassiceps cysticerci. Offspring from nonsupplemented mothers were used as controls. Significantly fewer parasites were recovered from zinc-supplemented mice (Zsm) 30 days after infection. Increased resistance was not related to the IgG antibody response. At early stages of infection, T cells from Zsm proliferated to T. crassiceps antigens, whereas cells from control mice did not respond. Infection caused in both groups a decrease in CD3+ cell percentages, which was more pronounced in the controls, and paralleled by a decrease in CD8+ cells; CD3+ and CD8+ percentages returned to normal levels at later stages of infection. In contrast, the CD4+ subpopulation only decreased in control mice. Intracellular cytokine determinations indicate that zinc supplementation favored a stronger and persistent type-1 T cell response in cysticerci-infected mice, which probably participates in the observed increased resistance.

Zinc intervention on macrophages and lymphocytes response

Normal zinc levels are essential for the development and maintenance of immune functions; Zn deficiency is detrimental to the embryo and offspring of experimental animals, especially concerning immune development. It is known that Zn supplementation improves immune responses. To further explore the relation between Zn administration and the metal in vitro effects, we studied zinc (500 mg/l) supplementation impact on lymphocytes and macrophages and zinc in vitro effects, in BALB/c mice supplemented from gestation to lactation. Results show a significant increase in proliferation (assessed by 3H incorporation) in lymphocytes exposed to Zn (0.1 mM) in vitro, in 3-wk-old mice; this effect is annulled when the supplementation period is lengthened, indicating saturation of the mechanisms involved in zinc induced stimulation. Macrophages functional capacity assessed by erythrophagocytosis was also improved by Zn supplementation and furthermore by the in vitro exposure to the metal, in mice 3 wk old, this was also depressed by Zn accumulation due to the supplementation period extension (9 weeks). Results show an improvement in the immune parameters analysed due to zinc supplementation and to zinc in vitro exposure. Results also suggest the accumulation of zinc as a result of prolonged supplementation periods, suppresses the cells response to zinc in vitro.

Increment of immune responses in mice perinatal stages after zinc supplementation

A model of BALB/c mice was developed to determine the effects of zinc supplements on immune responses during certain stages of ontogeny. The mice received zinc acetate in drinking water concentrations of 500 and 1000 mg/l during the periods of gestation, lactation and postweaning. The sequence employed in this study was: (I) 0/0 (II) 500/500 (III) 1000/1000 (IV) 0/0/0 (V) 500/500/500 and (VI) 1000/1000/1000 with their respective controls. No changes were observed in the general appearance, growth curves, hematocrit or signs of achromotrichia between treated and control animals. Group II and III showed a significant increase in 3H-thymidine-determined splenic lymphoproliferation, while groups V and VI exhibited an important decrease. A significant increase in plaque-forming cell response (IgM) was observed after the period of lactation in groups II and III as well as in groups V and VI. Zinc concentrations determined by atomic absorption in liver and thymus were significantly higher in all treated mice 42 days after birth. Results suggest that for carefully monitored periods and doses, oral zinc supplements might have a beneficial effect over some immune responses in the perinatal stages.

[Consequences of bacterial product interaction with the immune system in newborn mice]

The immunological competence of a newborn mice group, inoculated with a heat killed suspension of staphylococci, was studied to find out if the treated mice preserved the immunological competence of the T lymphocytes, for induce an allograft. A group of CD1 newborn male mice were injected intraperitoneally with the bacterial suspension, every three days during a four weeks period. Other group received only isotonic saline solution. The lymphocyte ability to form hemolytic plaques and their capacity to provoke a local graft-versus-host reaction in F1 receptor animals was studied in both groups. The results showed that the staphylococci treated newborn mice had a decreased capacity to form anti-erythrocyte antibodies without modification in their reactivity against histoincompatible antigens. Newborn mice, runting-like disease; bacterial inoculation; immunological response in.