CRISPR-based oligo recombineering prioritizes apicomplexan cysteines for drug discovery

Nucleophilic amino acids are important in covalent drug development yet underutilized as anti-microbial targets. Chemoproteomic technologies have been developed to mine chemically accessible residues via their intrinsic reactivity towards electrophilic probes but cannot discern which chemically reactive sites contribute to protein function and should therefore be prioritized for drug discovery. To address this, we have developed a CRISPR-based oligo recombineering (CORe) platform to support the rapid identification, functional prioritization and rational targeting of chemically reactive sites in haploid systems. Our approach couples protein sequence and function with biological fitness of live cells. Here we profile the electrophile sensitivity of proteinogenic cysteines in the eukaryotic pathogen Toxoplasma gondii and prioritize functional sites using CORe. Electrophile-sensitive cysteines decorating the ribosome were found to be critical for parasite growth, with target-based screening identifying a parasite-selective anti-malarial lead molecule and validating the apicomplexan translation machinery as a target for ongoing covalent ligand development.

Bladder cancer, drinking water source, and tap water consumption: a case-control study

Data from a population-based case-control interview study of incident bladder cancer in 10 areas of the United States were used to estimate relative risks among white men (2,116 cases, 3,892 controls) and women (689 cases, 1,366 controls) according to beverage intake level and type of water source. Individual year-by-year profiles of water source and treatment were developed by linking lifetime residential information with historical water utility data from an ancillary survey. Risk of bladder cancer increased with intake level of beverages made with tap water. The odds ratio (OR) for the highest vs. lowest quintile of tap water consumption was 1.43 [95% confidence interval (CI) = 1.23, 1.67; chi 2 for trend = 26.3, P less than .001]. The risk gradient with intake was restricted to persons with at least a 40-year exposure to chlorinated surface water and was not found among long-term users of nonchlorinated ground water. The ORs for the highest vs. lowest quintiles of tap water intake were 1.7 and 2.0, respectively, among subjects with 40-59 and greater than or equal to 60 years' exposure. Duration of exposure to chlorinated surface water was associated with bladder cancer risk among women and nonsmokers of both sexes. Among non-smoking respondents with tap water consumption above the population median, the OR increased with exposure duration to a level of 3.1 (CI = 1.3, 7.3; chi 2 for trend = 6.3, P = .01) for greater than or equal to 60 years of residence at places served by chlorinated surface water (vs. non-chlorinated ground water users). These results extend findings of earlier epidemiologic studies and are consistent with environmental chemistry and toxicologic data demonstrating the presence of genotoxic by-products of chlorine disinfection in treated surface waters.

Use of hair dyes and risk of bladder cancer

The relation between use of hair dyes and risk of bladder cancer was assessed using data from a case-control study of bladder cancer. Incident cases (2982) and general population controls (5782) were interviewed. The overall estimate of relative risk of bladder cancer for users of hair dyes was 1.0 (95%) confidence interval, 0.9 to 1.2) compared to nonusers. No consistent pattern of association was detected between bladder cancer risk and various indices of timing or intensity of exposure to hair dyes. Various explanations of the lack of association are discussed.

Noncancer deaths in cancer and noncancer lineages

Starting with white probands who were potential milk donors in a program of human milk collection, a series of 2411 family health histories were obtained of the first degree relatives of the probands' parents. A lineage is defined as the parents and siblings of a parent of the proband as well as the parent. 2090 cancers were identified in the 31,939 people. Of the 21,712 persons without cancer in the parents' generation, age-specific death rates were significantly higher in those lineages with at least one cancer. This was true in infants, children and adults for both males and females (p less than 0.001). Cancer may be linked to other morbid conditions by a commonality of heredity, family environment, or perhaps both as necessary antecedents--neither sufficient by itself.