QSAR of clinically important EGFR mutant L858R/T790M pyridinylimidazole inhibitors

EGFR is a well‐established therapeutic target of clinical relevance in cancer. However, acquisition of secondary mutation (T790M) makes first‐generation inhibitors ineffective. Therefore, to circumvent the problem of resistance, new T790M/L858R (TMLR) double mutant inhibitors are required. In this study, fragment‐based QSAR models (GQSAR) were generated for pyridinylimidazole derivatives having biological activity against TMLR mutants. The GQSAR model developed using partial least squares regression via stepwise forward–backward variable selection technique showed best results as judged using statistical parameters (r², q², and pred_r²). Additionally, applicability domain of the model was verified using Williams plot, which indicated that the predicted data are reliable. The GQSAR provided site‐specific clues wherein modifications related to decreasing lipophilic character and rotatable bonds and increasing SaaCHE‐index are required for improving inhibitory activity. Overall, the study indicated that the presence of acrylamide at R5 is essential for covalent bond formation with Cys797 and occurrence of aromatic residue at R2 is required for occupying hydrophobic region next to Met790 gatekeeper residue. Based on this information, new derivatives were designed that show better inhibitory activity than the experimentally reported most active molecules. Thus, the model developed can be used to design new pyridinylimidazole derivatives with improved TMLR bioactivity.     

A Team-Based Approach to Introduce and Sustain the Use of the WHO Surgical Safety Checklist in Tanzania

Introduction

Millions of patients worldwide suffer disability and death due to complications related to surgery. Many of these complications can be reduced by the use of the World Health Organization (WHO) Surgical Safety Checklist (SSC), a simple tool that can enhance teamwork and communication and improve patient safety. Despite the evidence on benefits of its use, introducing and sustaining the use of the checklist are challenging. We present a team-based approach employed in a low-resource setting in Tanzania, which resulted in high checklist utilization and compliance rates.

Methods

We reviewed reported data from facility registers supplemented by direct observation data by mentors to evaluate the use of the WHO SSC across 40 health facilities in two regions of Tanzania between January and December 2018. We analyzed the self-reported monthly data on total number of major surgeries performed and proportion of surgeries where the checklist was used. We also analyzed the use of the SSC during direct observation by external mentors and completion rates of the SSC in a random selection of patient files during two mentorship visits between June and December 2018.

Results

During the review period, the average self-reported checklist utilization rate was 79.3% (11,564 out of 14,580 major surgeries). SSC utilization increased from 0% at baseline in January 2018 to 98% in December 2018. The proportion of checklists that were completely and correctly filled out increased between the two mentor visits from 82.1 to 92.8%, but the gain was significantly greater at health centers than at hospitals (p < 0.05). Health centers (which had one or two surgical teams) self-reported a higher checklist utilization rate than hospitals (which had multiple surgical teams), i.e., 99.4% vs 68.8% (p < 0.05).

Conclusion and recommendations

Our findings suggest that Surgical Safety Checklist implementation is feasible even in lower-resource settings. The self-reported SSC utilization rate is higher than reported in other similar settings. We attribute this finding to the team-based approach employed and the ongoing regular mentorship. We recommend use of this approach to scale-up checklist use in other regions in the country as recommended in the Ministry of Health of Tanzania’s National Surgical, Obstetric, and Anesthesia Plan (NSOAP).

     

Cervical and vulvar cancer risk in relation to the joint effects of cigarette smoking and genetic variation in interleukin 2

Cigarette smoking is an established cofactor to human papillomavirus (HPV) in the development of cervical and vulvar squamous cell carcinoma (SCC), and may influence risk through an immunosuppressive pathway. Genetic variation in interleukin 2 (IL2), associated in some studies with the inhibition of HPV-targeted immunity, may modify the effect of smoking on the risk of HPV-related anogenital cancers. We conducted a population-based case-only study to measure the departure from a multiplicative joint effect of cigarette smoking and IL2 variation on cervical and vulvar SCC. Genotyping of the four IL2 tagSNPs (rs2069762, rs2069763, rs2069777, and rs2069778) was done in 399 cervical and 486 vulvar SCC cases who had been interviewed regarding their smoking history. Compared with cases carrying the rs2069762 TT genotype, we observed significant departures from multiplicativity for smoking and carriership of the TG or GG genotypes in vulvar SCC risk [interaction odds ratio (IOR), 1.67; 95% confidence interval (CI), 1.16-2.41]. Carriership of one of three diplotypes, together with cigarette smoking, was associated with either a supramultiplicative (TGCT/GGCC; IOR, 2.09; 95% CI, 0.98-4.46) or submultiplicative (TTCC/TGTC; IOR, 0.37; 95% CI, 0.16-0.85 or TGCT/TGCC; IOR, 0.37; 95% CI, 0.15-0.87) joint effect in vulvar cancer risk. For cervical SCC, departure from multiplicativity was observed for smokers homozygous for the rs2069763 variant allele (TT versus GG or GT genotypes; IOR, 1.87; 95% CI, 1.00-3.48), and for carriership of the TTCC/TTCC diplotype (IOR, 2.08; 95% CI, 1.01-4.30). These results suggest that cervical and vulvar SCC risk among cigarette smokers is modified by genetic variation in IL2.     

Acetylcholine-induced desensitization of the contractile response to histamine in Guinea pig ileum is prevented by either pertussis toxin treatment or by selective inactivation of muscarinic M(3) receptors

We have studied the role of M(2) and M(3) muscarinic receptors in acetylcholine-mediated desensitization of the contractile response to histamine in the guinea pig ileum. Treatment of the isolated ileum with acetylcholine (30 microM) for 20 min caused a marked desensitization of the contractile response to histamine. When measured 5 min after washout of acetylcholine, the EC(50) value of histamine increased 5.8-fold compared with that estimated before acetylcholine treatment, whereas the maximal response was unaffected. This shift in the EC(50) value of histamine was maximal at the earliest time measured after acetylcholine treatment (5 min), and normal sensitivity recovered in approximately 20 min. Acetylcholine-induced desensitization was prevented by uncoupling of M(2) receptors from G(i) with pertussis toxin or by selective inactivation of M(3) receptors with N-2-chloroethyl-4-piperidinyl diphenylacetate (4-DAMP mustard). The shifts in the EC(50) values of histamine measured 5 min after acetylcholine treatment were only 2.0- and 1.8-fold in pertussis toxin- and 4-DAMP mustard-treated ilea, respectively. Both pertussis toxin- and 4-DAMP mustard-treatment had little or no effect on histamine-induced contractions in control ileum. Measurement of histamine-stimulated inositol phosphate accumulation in the longitudinal muscle of the ileum showed little or no inhibitory effect of prior exposure to acetylcholine, indicating that the majority of the heterologous desensitization occurs downstream from phospholipase Cbeta activation. Collectively, our results suggest that activation of both M(2) and M(3) receptors is required for heterologous desensitization of histamine-mediated contractions in the guinea pig ileum.     

Impaired function of Fanconi anemia type C-deficient macrophages

FA is a genetic disorder characterized by BM failure, developmental defects, and cancer predisposition. Previous studies suggest that FA patients exhibit alterations in immunologic function. However, it is unclear whether the defects are immune cell-autonomous or secondary to leukopenia from evolving BM failure. Given the central role that macrophages have in the innate immune response, inflammation resolution, and antigen presentation for acquired immunity, we examined whether macrophages from Fancc-/- mice exhibit impaired function. Peritoneal inflammation induced by LPS or sodium periodate resulted in reduced monocyte/macrophage recruitment in Fancc-/- mice compared with WT controls. Fancc-/- mice also had decreased inflammatory monocytes mobilized into the peripheral blood after LPS treatment compared with controls. Furthermore, Fancc-/- peritoneal macrophages displayed cell-autonomous defects in function, including impaired adhesion to FN or endothelial cells, reduced chemoattractant-mediated migration, and decreased phagocytosis. Moreover, dysregulated F-actin rearrangement was detected in Fancc-/- macrophages after adhesion to FN, which was consistent with an observed reduction in RhoA-GTP levels. Importantly, these data suggest that impaired cytoskeletal rearrangements in Fancc-/- macrophages may be the common mechanism responsible for cell-autonomous defects detected in vitro, as well as altered monocyte/macrophage trafficking in vivo.     

A candidate CpG SNP approach identifies a breast cancer associated ESR1-SNP

Altered DNA methylation is often seen in malignant cells, potentially contributing to carcinogenesis by suppressing gene expression. We hypothesized that heritable methylation potential might be a risk factor for breast cancer and evaluated possible association with breast cancer for single nucleotide polymorphisms (SNPs) either involving CpG sequences in extended 5'-regulatory regions of candidate genes (ESR1, ESR2, PGR, and SHBG) or CpG and missense coding SNPs in genes involved in methylation (MBD1, MECP2, DNMT1, MGMT, MTHFR, MTR, MTRR, MTHFD1, MTHFD2, BHMT, DCTD, and SLC19A1). Genome-wide searches for genetic risk factors for breast cancers have in general not investigated these SNPs, because of low minor allele frequency or weak haplotype associations. Genotyping was performed using Mass spectrometry-Maldi-Tof in a screening panel of 538 cases and 1,067 controls. Potential association to breast cancer was identified for 15 SNPs and one of these SNPs (rs7766585 in ESR1) was found to associate strongly with breast cancer, OR 1.30 (95% CI 1.17-1.45; p-value 2.1 × 10(-6)), when tested in a verification panel consisting of 3,211 unique breast cancer cases and 4,223 unique controls from five European biobank cohorts. In conclusion, a candidate gene search strategy focusing on methylation-related SNPs did identify a SNP that associated with breast cancer at high significance.     

Nucleotide variation in IL‐10 and IL‐12 and their receptors and cervical and vulvar cancer risk: A hybrid case–parent triad and case–control study

Given the important role of cell mediated immunity in viral clearance and control of premalignant lesions, we hypothesize that variation in the IL‐12/IL‐10 cytokine and cytokine receptor genes may influence cervical and vulvar cancer risk. We evaluated 76 tagSNPs from seven candidate genes (IL-10, IL-12A, IL-12B, IL-10RA, IL-10RB, IL-12RB1, and IL12RB2) in case–parent sets (n=43 cervical squamous cell carcinoma (SCC), n=96 cervical adenocarcinoma, n=53 vulvar SCC), additional cases (n=356 cervical SCC, n=406 cervical adenocarcinoma, and n=473 vulvar SCC) and population based controls (1,111). We calculated log‐additive odds ratios (ORs) and 95% confidence intervals (CIs) for the association between tagSNP and cancer risk using a pseudo‐likelihood based method which combined genotype information on cases, parents, and population controls. After correction for multiple comparisons, we identified several statistically significant SNP associations. Cervical SCC risk was associated with the minor alleles of the IL10RA rs9610 3’ UTR SNP (OR=1.76, 95% CI=1.15–2.68) and two synonymous IL12RB2 SNPs (rs4297265, OR=0.46, 95% CI=0.26–0.82; rs2229546, OR=0.43, 95% CI=0.21–0.87). Cervical adenocarcinoma risk was associated with the minor alleles of the IL10RA rs4252314 intronic SNP (OR=2.23, 95% CI=1.26–3.96) and IL12RB1 rs11575934 non‐synonymous SNP (OR=1.51, 95% CI=1.12–2.05). Finally, the minor allele of the IL12B rs3181224 3’ UTR SNP was associated with a reduced risk of vulvar SCC (OR=0.30, 95% CI=0.12–0.74). These results raise the possibility that a shift in the balance of the immune response due to genetic variants in key cytokine genes could influence the development of cervical and vulvar cancer.     

Influence of education level on breast cancer risk and survival in Sweden between 1990 and 2004

On account of limited recent data regarding the role of education in breast cancer risk and prognosis, we conducted this study to assess the association between education level and in situ and invasive breast cancer risk and invasive breast cancer survival, using the 2006 update of the Swedish Family-Cancer Database. Cox's proportional hazards models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) adjusted for age, time-period, parity, age at first birth, county of residence, and family history of breast cancer. Compared to women completing less than 9 years of education, university graduates were more likely to be diagnosed with in situ (HR = 1.44, 95% CI: 1.28-1.63) and invasive (HR = 1.28, 95% CI: 1.20-1.36) breast cancer, and the lack of homogeneity between these two HRs was statistically significant, p = 0.007. Further stratification revealed that the lack of homogeneity was greatest for breast cancers diagnosed before age 50. Compared to women completing less than 9 years of education, university graduates were associated with the highest survival following a breast cancer diagnosis (lowest fatality hazard ratio), HR = 0.68, 95% CI: 0.61-0.75. Further research is warranted to elucidate possible behaviors or characteristics associated with education that could explain the differences in incidence and survival, such as compliance with cancer screening.