Establishing Drug Discovery and Identification of Hit Series for the Anti-apoptotic Proteins, Bcl-2 and Mcl-1

We describe our work to establish structure- and fragment-based drug discovery to identify small molecules that inhibit the anti-apoptotic activity of the proteins Mcl-1 and Bcl-2. This identified hit series of compounds, some of which were subsequently optimized to clinical candidates in trials for treating various cancers. Many protein constructs were designed to identify protein with suitable properties for different biophysical assays and structural methods. Fragment screening using ligand-observed NMR experiments identified several series of compounds for each protein. The series were assessed for their potential for subsequent optimization using ¹H and ¹⁵N heteronuclear single-quantum correlation NMR, surface plasmon resonance, and isothermal titration calorimetry measurements to characterize and validate binding. Crystal structures could not be determined for the early hits, so NMR methods were developed to provide models of compound binding to guide compound optimization. For Mcl-1, a benzodioxane/benzoxazine series was optimized to a K _d of 40 μM before a thienopyrimidine hit series was identified which subsequently led to the lead series from which the clinical candidate S 64315 (MIK 665) was identified. For Bcl-2, the fragment-derived series were difficult to progress, and a compound derived from a published tetrahydroquinone compound was taken forward as the hit from which the clinical candidate (S 55746) was obtained. For both the proteins, the work to establish a portfolio of assays gave confidence for identification of compounds suitable for optimization.

Medical professionalism--who cares?

Who cares about medical professionalism? It seems doctors, patients and, surprisingly, the media do. The relevance of medical professionalism for these three groups is examined from the journalist's/patient's point of view. The report and findings of the Royal College of Physicians Working Party on Medical Professionalism is discussed. In conclusion there is a synopsis of recommendations and future action required by individuals from all three groups to enable progress to be made in this important area of communication.

Estimation of the use of dietary supplements in the National Diet and Nutrition Survey: people aged 65 years and Over. An observed paradox and a recommendation

OBJECTIVE

To compare the evidence derived from blood biochemical status indices with the evidence from a questionnaire and from a 4-day weighed dietary record of micronutrient supplement use in the British National Diet and Nutrition Survey (NDNS) of People Aged 65 Years and Over; to resolve some apparent incompatibility between nutrient intake and status estimates, and to recommend an approach towards supplement recording that should improve accuracy.

DESIGN

The survey procedures described in the National Diet and Nutrition Survey Report (1998) included a health-and-lifestyle questionnaire, a 4-day weighed diet record, and fasting blood and urine sample for biochemical indices, including a wide range of micronutrients.

SETTING

Eighty randomly selected postcode sectors from mainland Britain during 1994-1995.

SUBJECTS

Of 2060 people interviewed, 1467 provided a blood sample and 1217 provided both a blood sample, and a complete 4-day diet record. About 20% were living in institutions such as nursing homes, and the remainder were living in private households.

RESULTS

After assigning the subjects to four categories by the use of dietary supplements (A, those not taking supplements (by questionnaire or by the 4-day record); B, those taking supplements (excluding prescribed ones) by questionnaire only; C, those taking supplements by 4-day record only; and D, those taking supplements by both questionnaire and 4-day record), these categories were then compared with respect to estimated total nutrient intakes and blood biochemical indices. Those in category B had estimated (4-day) nutrient intakes (from foods and supplements) that were indistinguishable from those in category A, but had biochemical indices that indicated significantly higher dietary intakes of several vitamins. CONCLUSIONS AND RECOMMENDATION: The 4-day weighed intake record may not have identified all of the subjects who were regularly taking micronutrient supplements in amounts sufficient to improve their biochemical status. Because survey respondents may use supplements irregularly or change their usual patterns of supplement use during a period of intensive diet-recording, it is important to design a dietary instrument that will minimise this potential source of inaccuracy. We therefore recommend that population surveys in which an accurate estimate of micronutrient intakes is required, from supplements as well as from food, should record supplement use for a period longer than 4-days. It is likely that a better estimate of long-term intakes can be achieved by combining a 4-day weighed diet record with a structured recall or several weeks of diary records, which focus specifically on the use of supplements.

Molecular scene analysis: the integration of direct-methods and artificial-intelligence strategies for solving protein crystal structure

A knowledge-based approach to crystal structure determination is presented. The approach integrates direct-methods and artificial-intelligence strategies to rephrase the structure determination process as an exercise in scene analysis. A general joint probability distribution framework, which allows the incorporation of isomorphous replacement, anomalous scattering and a priori structural information, forms the basis of the direct-methods strategies. The accumulated knowledge on crystal and molecular structures is exploited through the use of artificial-intelligence strategies, which include techniques of knowledge representation, search and machine learning.