Understanding the Antiproliferative Activity of Plant Extracts

Many plants possess medicinal properties. Some, such as the Pacific yew, have yielded chemotherapeutic drugs (taxanes). Scientists report that other extracts such as the leaves of Calendula officinalis (marigold), Vinca rosea (periwinkle), Viscum cruciatum (mistletoe), and Rosmarinus officinalis (rosemary) have anti-tumor activity. In most cases, the chemical components responsible for antiproliferative activity have not been identified and it is unclear if any individual components are as effective in isolation as they are in the context of the whole extract. Furthermore, in most cases, there are no data indicating whether these extracts have synergistic effects or cause negative reactions when used with other drugs. We are using HeLa (adenocarcinoma), RAW 264.7 (leukemia), HepG2 (hepatoma), MDA-MB-231 (adenocarcinoma), and human foreskin fibroblasts (HFF, non-tumorigenic) to test the antiproliferative activity of several plant extracts. We identified five extracts, grapeseed, guava, yew, juniper berry, and Vinca, that slow the growth of all five cell lines in a dose-dependent manner. We are using a variety of methods to understand the mechanism by which these extracts are blocking cell growth

Methylation-associated PHOX2B gene silencing is a rare event in human neuroblastoma.

International audienceNeuroblastoma (NB), an embryonic tumour originating from neural crest cells, is one of the most common solid tumours in childhood. Although NB is characterised by numerous recurrent, large-scale chromosome rearrangements, the genes targeted by these imbalances have remained elusive. We recently identified the paired-like homeobox 2B (PHOX2B, MIM 603851) gene as disease-causing in dysautonomic disorders including Congenital Central Hypoventilation Syndrome (CCHS), Hirschsprung disease (HSCR) and NB in various combinations. Most patients with NB due to a germline heterozygous PHOX2B gene mutation are familial and/or syndromic. PHOX2B, at chromosome 4p12, does not lie in a commonly rearranged locus in NB. To evaluate the role of PHOX2B in sporadic, isolated NB, we analysed 13 NB cell lines and 45 tumours for expression, mutations of coding and promoter sequences, loss of heterozygosity (LOH), or aberrant hypermethylation of PHOX2B (13 cell lines and 18 tumours). We didn't identify any mutation but LOH in about 10% of the cases and aberrant CpG dinucleotide methylation of the 500 bp PHOX2B promoter region in 4/31 tumours and cell lines (12.9%). Altogether, both germinal and somatic anomalies at the PHOX2B locus are found in NB

Pregnancy exposure registries for drugs and vaccines in low-income and middle-income countries: scoping review protocol

Introduction Data regarding the safety of drugs and vaccines in pregnant women are typically unavailable before licensure. Pregnancy exposure registries (PERs) are an important source of postmarketing safety information. PERs in low-income and middle-income countries (LMICs) are uncommon but can provide valuable safety data regarding their distinct contexts and will become more relevant as the introduction and use of new drugs and vaccines in pregnancy increase worldwide. Strategies to support PERs in LMICs must be based on a better understanding of their current status. We developed a scoping review protocol to assess the landscape of PERs that operate in LMICs and characterise their strengths and challenges.Methods and analysis This scoping review protocol follows the Joanna Briggs Institute manual for scoping reviews. The search strategy will be reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews Checklist. We will search PubMed, Embase, CINAHL and WHO’s Global Index Medicus, as well as the reference lists of retrieved full-text records, for articles published between 2000 and 2022 that describe PERs or other resources that systematically record exposures to medical products during pregnancy and maternal and infant outcomes in LMICs. Title and abstracts will be screened by two authors and data extracted using a standardised form. We will undertake a grey literature search using Google Scholar and targeted websites. We will distribute an online survey to selected experts and conduct semistructured interviews with key informants. Identified PERs will be summarised in tables and analysed.Ethics and dissemination Ethical approval is not required for this activity, as it was determined not to involve human subjects research. Findings will be submitted to an open access peer-reviewed journal and may be presented at conferences, with underlying data and other materials made publicly available

A trisubstituted benzimidazole cell division inhibitor with efficacy against Mycobacterium tuberculosis.

Trisubstituted benzimidazoles have demonstrated potency against Gram-positive and Gram-negative bacterial pathogens. Previously, a library of novel trisubstituted benzimidazoles was constructed for high throughput screening, and compounds were identified that exhibited potency against M. tuberculosis H37Rv and clinical isolates, and were not toxic to Vero cells. A new series of 2-cyclohexyl-5-acylamino-6-N, N-dimethylaminobenzimidazoles derivatives has been developed based on SAR studies. Screening identified compounds with potency against M. tuberculosis. A lead compound from this series, SB-P17G-A20, was discovered to have an MIC of 0.16 µg/mL and demonstrated efficacy in the TB murine acute model of infection based on the reduction of bacterial load in the lungs and spleen by 1.73 ± 0.24 Log10 CFU and 2.68 ± Log10 CFU, respectively, when delivered at 50 mg/kg by intraperitoneal injection (IP) twice daily (bid). The activity of SB-P17G-A20 was determined to be concentration dependent and to have excellent stability in mouse and human plasma, and liver microsomes. Together, these studies demonstrate that SB-P17G-A20 has potency against M. tuberculosis clinical strains with varying susceptibility and efficacy in animal models of infection, and that trisubstituted benzimidazoles continue to be a platform for the development of novel inhibitors with efficacy

Killing characteristics of SB-P17G

<p>-<b>A20 against whole bacteria.</b> The time dose curves were generated from OD_{600 nm} (a) and from CFU enumeration (b) data. Different concentrations of the compound were tested in triplicate and the mean and standard deviation of the OD_{600 nm} values or the CFU counts from Day 0, 2, 4, and 6 were plotted against time using GraphPad Prism Version 5.0d for Mac OS X (GraphPad Software, San Diego CA., USA, <a href="http://www.graphpad.com" target="_blank">www.graphpad.com</a>).</p

Activity of SB-P17G-A20 against <i>M. tuberculosis</i> clinical isolates.

<p>Dose response curves were generated from MABA data for <i>M. tuberculosis</i> strains (H37Rv, TN587, NHN382, W210 and NHN20) treated with SB-P17G-A20. The curves were generated by graphing the log₁₀ drug concentrations against the difference in growth between the drug treated wells and control wells using GraphPad Prism Version 5.0d for Mac OS X (GraphPad Software, San Diego CA., USA, <a href="http://www.graphpad.com" target="_blank">www.graphpad.com</a>).</p

Structure of lead benzimidazoles.

<p>Structure of lead benzimidazoles.</p

Transmission Electron Microscopy of FtsZ.

<p>FtsZ (5 µM) was polymerized by GTP (25 µM) in the absence (A) and presence of SB-P17G-A20 at 40 µM (B) and 80 µM (C). Images are at 49,000x magnification (scale bar 500 nm).</p

Efficacy of SB-P17G-A20 in a tuberculosis murine model of infection.

<p>Scatter plot of the CFU counts from the lung and spleens of infected mice after drug therapy with SB-P17G-A20 delivered IP at 50 mg/kg bid. The colony counts were converted to logarithms. The lower level of detection was 1 log₁₀ CFU. Outliers were identified by the Grubbs’ Test using an online calculator. (GraphPad Software, San Diego CA., USA <a href="http://www.graphpad.com" target="_blank">www.graphpad.com</a>). A scatter plot of the CFU data from the lung and spleen of individual mice from the treatment and control groups were plotted with the mean and SE from each group using GraphPad Prism Version 5.0d for Mac OS X (GraphPad Software, San Diego CA., USA <a href="http://www.graphpad.com" target="_blank">www.graphpad.com</a>).</p

Susceptibility of <i>M. tuberculosis</i> strains to SB-P17G-A20.

<p>Susceptibility of <i>M. tuberculosis</i> strains to SB-P17G-A20.</p