LIN28B promotes neuroblastoma metastasis and regulates PDZ binding kinase.

Neuroblastoma is an aggressive pediatric malignancy of the neural crest with suboptimal cure rates and a striking predilection for widespread metastases, underscoring the need to identify novel therapeutic vulnerabilities. We recently identified the RNA binding protein LIN28B as a driver in high-risk neuroblastoma and demonstrated it promotes oncogenic cell proliferation by coordinating a RAN-Aurora kinase A network. Here, we demonstrate that LIN28B influences another key hallmark of cancer, metastatic dissemination. Using a murine xenograft model of neuroblastoma dissemination, we show that LIN28B promotes metastasis. We demonstrate that this is in part due to the effects of LIN28B on self-renewal and migration, providing an understanding of how LIN28B shapes the metastatic phenotype. Our studies reveal that the let-7 family, which LIN28B inhibits, decreases self-renewal and migration. Next, we identify PDZ Binding Kinase (PBK) as a novel LIN28B target. PBK is a serine/threonine kinase that promotes the proliferation and self-renewal of neural stem cells and serves as an oncogenic driver in multiple aggressive malignancies. We demonstrate that PBK is both a novel direct target of let-7i and that MYCN regulates PBK expression, thus elucidating two oncogenic drivers that converge on PBK. Functionally, PBK promotes self-renewal and migration, phenocopying LIN28B. Taken together, our findings define a role for LIN28B in neuroblastoma metastasis and define the targetable kinase PBK as a potential novel vulnerability in metastatic neuroblastoma.

Promotion of zinc tablets with ORS through child health weeks improves caregiver knowledge, attitudes, and practice on treatment of diarrhoea in Nigeria.

We examined whether the Maternal, Newborn and Child Health Weeks (MNCHW) in Nigeria would present an opportunity to raise awareness of and demand for the use of zinc and ORS in the treatment for diarrhoea, guided by a conceptual framework designed to assess three theoretical underpinnings (characteristics and performance standard of the health workers, potential reach, and intensity of the intervention), along the impact pathway. Zinc and ORS with education for their appropriate use during the next diarrhoeal episode were delivered as part of the November 2010 and May 2011 MNCHW. On the day of but before participating in MNCHW activities, semi-structured interviews were used for collecting information on knowledge, attitudes, and practice (KAP) relating to diarrhoea from 602 caregivers with children aged less than five years. Forty-eight health workers were also interviewed. Nearly all health workers (98%) correctly mentioned the dosage of zinc while only 58% correctly stated the preparation of ORS. The proportion of caregivers with knowledge on the treatment for diarrhoea increased from 46.4% in November 2010 pre-MNCHW to 71.3% in May 2011 pre-MNCHW interviews (p<0.001). More caregivers correctly mentioned the dosage of zinc (80.9%) and stated the preparation of ORS (88.8%) in the November 2010 exit interview immediately after the MNCHW encounter compared to the levels a few months later in the home follow-up visit (53.1% and 37.4% respectively). After attending both rounds of November 2010 and May 2011 MNCHW, caregivers' knowledge on the treatment of diarrhoea increased seven times compared to the caregivers who attended the May 2011 MNCHW only (OR=7.0, p<0.001). Additionally, caregivers were 40% less likely to seek advice outside the home in the treatment for diarrhoea if they had attended both the MNCHWs than if they had attended the May 2011 MNCHW only (OR=0.6, p<0.029). We conclude that providing opportunities for caregivers to receive a sample of zinc and ORS and to learn about its use in the treatment for diarrhoea, from trained health workers during MNCHW, has the potential to increase KAP relating to the use of zinc and ORS in the treatment for diarrhoea and for future diarrhoeal episodes.

Antiplasmodial and analgesic activities of Clausena anisata.

OBJECTIVE: Antiplasmodial and analgesic activities of the leaf extract and fractions of Clausena anisata (C. anisata) were evaluated for antimalarial and analgesic activities. METHODS: The crude leaf extract (39-117 mg/kg) and fractions (chloroform and acqeous; 78 mg/kg) of C. anisata were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei (P. berghei) infections in mice using suppressive, prophylactic and curative models and analgesic activity against acetic acid, formalin and heat-induced pains. Artesunate, 5 mg/kg and pyrimethamine, 1.2 mg/kg were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. RESULTS: The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine-sensitive P. berghei in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (P<0.001). They also improved the mean survival time (MST) from 17 to 21 days relative to control (P<0.01 - 0.001). On chemically and thermally-induced pains, the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice. These inhibitions were statistically significant (P<0.001) and in a dose-dependent fashion. CONCLUSIONS: The antiplasmodial and analgesic effects of this plant may in part be mediated through its chemical constituents and it can be concluded that the C. anisata possess significant antimalarial and analgesic properties.

Antidiarrheal mechanism of Carpolobia lutea leaf fractions in rats.

CONTEXT: Carpolobia lutea G. Don (Polygalaceae) leaf is reputable as an antidiarrheal agent among the Efik and Ibibio tribe of Akwa Ibom State, Nigeria. The crude extract is reported to show antidiarrheal and antiulcer effects in rodents. OBJECTIVE: The isolation and characterization of drug molecules from the leaf fraction with antidiarrheal bioactivity and determination of mechanism of action are reported. MATERIAL AND METHODS: Gradient extraction by maceration yielding n-hexane, chloroform, ethyl acetate, and ethanol fractions (770 mg/kg) were used to establish the fractions suitable for drug discovery. The antidiarrheal effect of the leaf fractions of Carpolobia lutea was evaluated using castor oil-induced diarrhea, castor oil-induced intestinal transit, and enteropooling. RESULTS: Results indicate that all fractions produced a significant (p < 0.01-0.001) decrease in castor oil-induced diarrhea in rats. This effect was not antagonized by isosorbide dinitrate (150 mg/kg, p.o), diphenoxylate (5 × 10⁻³ mg/kg p.o) and yohimbine (1 mg/kg, s.c.) except for the chloroform fraction. The ethyl acetate fraction produced 100% inhibition of intestinal transit, an effect greater than pure drug. Phytochemical analysis of the ethyl acetate fraction yielded polyphenolic compounds. CONCLUSION: The leaf fractions contain two types of antidiarrheal agents, one mediating its effect through α1-presynaptic adrenoceptor while the other does not. Polyphenols isolated may in part lend credence for observed antidiarrheal activity.