The multidrug resistance protein is photoaffinity labeled by a quinoline-based drug at multiple sites

Tumor cells overcome cytotoxic drug pressure by the overexpression of either or both transmembrane proteins, the P-glycoprotein (P-gp) and the multidrug resistance protein (MRP). The MRP has been shown to mediate the transport of cytotoxic natural products, in addition to glutathione-, glucuronidate-, and sulfate-conjugated cell metabolites. However, the mechanism of MRP drug binding and transport is at present not clear. In this study, we have used a photoreactive quinoline-based drug, N-(hydrocinchonidin-8'-yl)-4-azido-2-hydroxybenzamide (IACI), to show the photoaffinity labeling of the 190 kDa protein in membranes from the drug resistant SCLC H69/AR cells. The photoaffinity labeling of the 190 kDa protein by IACI was saturable and specific. The identity of the IACI-photolabeled protein as the MRP was confirmed by immunoprecipitation with the monoclonal antibody QCRL-1. Furthermore, a molar excess of leukotriene C(4), doxorubicin, colchicine, and other quinoline-based drugs, including MK571, inhibited the photoaffinity labeling of the MRP. Drug transport studies showed lower IACI accumulation in MRP-expressing cells which was reversed by depleting ATP levels in H69/AR cells. Mild digestion of the purified IACI-photolabeled MRP with trypsin showed two large polypeptides ( approximately 111 and approximately 85 kDa). The 85 kDa polypeptide which contains the QCRL-1 and MRPm6 monoclonal antibody epitopes corresponds to the C-terminal half of the MRP (amino acids approximately 900-1531) containing the third multiple spanning domain (MSD3) and the second nucleotide binding site. The 111 kDa polypeptide which contains the epitope sequence of the MRPr1 monoclonal antibody encodes the remainder of the MRP sequence (amino acids 1-900) containing the MSD1 and MSD2 plus the first nucleotide binding domain. Cleveland maps of purified IACI-labeled 85 and 111 kDa polypeptides revealed 6 kDa and approximately 6 plus 4 kDa photolabeled peptides, respectively. In addition, resolution of the exhaustively digested IACI-photolabeled MRP by HPLC showed two major and one minor radiolabeled peaks that eluted late in the gradient (60 to 72% acetonitrile). Taken together, the results of this study show direct binding of IACI to the MRP at physiologically relevant sites. Moreover, IACI photolabels three small peptides which localize to the N- and C-halves of the MRP. Finally, IACI provides a sensitive and specific probe for studying MRP-drug interactions.     

Long-distance travel for birthing among Indigenous and non-Indigenous pregnant people in Canada

BACKGROUND:For Indigenous Peoples in Canada, birthing on or near traditional territories in the presence of family and community is of foundational cultural and social importance. We aimed to evaluate the association between Indigenous identity and distance travelled for birth in Canada.METHODS:We obtained data from the Maternity Experiences Survey, a national population-based sample of new Canadian people aged 15 years or older who gave birth (defined as mothers) and were interviewed in 2006–2007. We compared Indigenous with non-Indigenous Canadian-born mothers and adjusted for geographic and sociodemographic factors and medical complications of pregnancy using multivariable logistic regression. We categorized the primary outcome, distance travelled for birth, as 0 to 49, 50 to 199 or 200 km or more.RESULTS:We included 3100 mothers living in rural or small urban areas, weighted to represent 31 100 (1800 Indigenous and 29 300 non-Indigenous Canadian-born mothers). We found that travelling 200 km or more for birth was more common among Indigenous compared with non-Indigenous mothers (9.8% v. 2.0%, odds ratio [OR] 5.45, 95% confidence interval [CI] 3.52–8.48). In adjusted analyses, the association between Indigenous identity and travelling more than 200 km for birth was even stronger (adjusted OR 16.44, 95% CI 8.07–33.50) in rural regions; however, this was not observed in small urban regions (adjusted OR 1.04, 95% CI 0.37–2.91).INTERPRETATION:Indigenous people in Canada experience striking inequities in access to birth close to home compared with non-Indigenous people, primarily in rural areas and independently of medical complications of pregnancy. This suggests inequities are rooted in the geographic distribution of and proximal access to birthing facilities and providers for Indigenous people.

Access to birth close to home, surrounded by loved ones, is taken for granted by most Canadians. The societal importance of family support during birthing has been highlighted during the severe acute respiratory syndrome and COVID-19 pandemics, despite the known and potentially fatal risks to hospital visitors, because people in labour have been one of the few patient groups exempt from visitor restrictions.^1,2 For residents living in rural areas of Canada, long-distance travel for birth is a reality that is becoming increasingly common in some regions because of closures of obstetrical services in smaller community hospitals.³ This is only partially mitigated by the revitalization of rural midwifery practice.^4,5Emerging evidence shows that the frequency of adverse medical events during labour and delivery for rural populations is similar for births that take place close to home and births for which people travel because of an absence of services close to home.^3,4,6 Less is known about the impacts of travel for birth on breastfeeding rates, maternal mental health and family functioning. Several studies have documented the negative impacts of birthing away from home with respect to maternal satisfaction and birth experience.^7–10 This evidence is particularly compelling for Indigenous populations for whom birthing on or near traditional territories in the presence of family and community is a long-standing practice of foundational cultural and social importance that contributes to well-being, cultural continuity and kinship.^7–12The striking isolation, family disruption and racism experienced by Indigenous people who are forced to travel alone for birth as a result of externally imposed federal “evacuation for birth” policies¹¹ has been met with a series of policy initiatives to support return of birth to rural and remote Indigenous communities. ^13–15 In April 2017, then federal Minister of Health Dr. Jane Philpott, committed to “a path to be able to return the cries of birth” to Indigenous communities and funding to support travel for a companion when Indigenous people living in rural and remote areas needed to travel away from home for birth.¹⁶ Before 2017, Indigenous pregnant people often travelled and birthed away from home alone without family or community support, because escorts were not deemed medically necessary. Although these initiatives have improved access to Indigenous perinatal programming and Indigenous birth attendant support in some local areas, over the past decade there has not been any substantial expansion of Indigenous birthing facilities outside of urban centres in Canada and at least 1 remote Indigenous birthing facility has closed.¹⁷Given this dynamic policy context, the national scope and Indigenous identifiers in the Canadian Maternity Experiences Survey (MES) provides a unique opportunity to quantify how often Indigenous and non-Indigenous people are travelling away from home for birth and to evaluate the association between Indigenous and non-Indigenous identity and distance travelled for birth in Canada.     

Landscape of Germline Genetic Variants in AGT,MGMT, and TP53 in Mexican Adult Patients with Astrocytoma

Cellular and Molecular Neurobiology - Astrocytoma is the most common type of primary brain tumor. The risk factors for astrocytoma are poorly understood; however, germline genetic variants account...     

Systematic Genetic Analysis Identifies Cis-eQTL Target Genes Associated with Glioblastoma Patient Survival

Prior expression quantitative trait locus (eQTL) studies have demonstrated heritable variation determining differences in gene expression. The majority of eQTL studies were based on cell lines and normal tissues. We performed cis-eQTL analysis using glioblastoma multiforme (GBM) data sets obtained from The Cancer Genome Atlas (TCGA) to systematically investigate germline variation’s contribution to tumor gene expression levels. We identified 985 significant cis-eQTL associations (FDR<0.05) mapped to 978 SNP loci and 159 unique genes. Approximately 57% of these eQTLs have been previously linked to the gene expression in cell lines and normal tissues; 43% of these share cis associations known to be associated with functional annotations. About 25% of these cis-eQTL associations are also common to those identified in Breast Cancer from a recent study. Further investigation of the relationship between gene expression and patient clinical information identified 13 eQTL genes whose expression level significantly correlates with GBM patient survival (p<0.05). Most of these genes are also differentially expressed in tumor samples and organ-specific controls (p<0.05). Our results demonstrated a significant relationship of germline variation with gene expression levels in GBM. The identification of eQTLs-based expression associated survival might be important to the understanding of genetic contribution to GBM cancer prognosis.     

Phytochemical analysis and fabrication of silver nanoparticles using Acacia catechu: An efficacious and ecofriendly control tool against selected polyphagous insect pests

Globally, the farmers are struggling with polyphagous insect pest, and it is the number one enemy of agri-products, which made plenty of economic deterioration. Spodoptera litura and Helicoverpa armigera are the agronomically important polyphagous pests. Most of the farmers are predominately dependent on synthetic chemical insecticides (SCIs) for battle against polyphagous pets. As a result, the broad spectrum usage of SCIs led a lot of detrimental outcomes only inconsequently the researchers search the former-friendly phyto-pesticidal approach. In the present investigation, leaf ethanol extract (LEE) and silver nanoparticles (AgNPs) of A. catechu (Ac) were subjected to various spectral (TLC, CC, UV, FTIR, XRD and SEM) analyses. Larval and pupal toxicity of A. catechu Ac-LEE and Ac-AgNPs were tested against selected polyphagous insect pests. The significant larval and pupal toxicity were experimentally proven, and the highest toxicity noticed in AgNPs than Ac-LEE. The larval and pupal toxicity of Ac-AgNPs tested against S. litura and H. armigera LC₅₀/LC₉₀ values were 71.04/ 74.78, 85.33/ 88.91 µg/mL and 92.57/ 96.21 and 124.43/ 129.95 µg/mL respectively. Ac-AgNPs could be potential phyto-pesticidal effectiveness against selected polyphagous insect pests. In globally, it is significantly sufficient ratification giving towards the prevention of many unauthorized SCPs.