Abstract Background: Elevated body mass index (BMI) is associated with increased risk of hormone receptor (HR)-positive breast cancer in postmenopausal women and worsened outcomes after breast cancer diagnosis. These observations may be partly attributable to adipose inflammation, which is prevalent in the breasts of obese women and is associated with worsened breast cancer survival. In men, some studies have reported obesity to be a risk factor for breast cancer, however the biologic links are not well characterized. Whether adipose inflammation occurs in male breast tissue has not been previously reported. Here we examined the relationships among pre-diagnosis BMI, adipose inflammation, and breast cancer features in men. Methods: Males diagnosed with stage 0 – III breast cancer who underwent mastectomy at Memorial Sloan Kettering (MSK) between August 1991 – November 2011 were included in this retrospective cohort study. Pre-operative BMI was categorized as normal or underweight (<25), overweight (25 – 29.9), obese (≥30), or morbidly obese (≥40 or ≥35 + co-morbidity). Archived breast tissue was subjected to CD68 immunohistochemistry to detect adipose inflammation, defined by the presence of dead or dying adipocytes surrounded by macrophages – known as crown-like structures of the breast (CLS-B). Clinicopathologic associations with BMI and CLS-B were analyzed by logistic regression and Fisher's exact test. Results: A total of 141 men were included; median age 63 (range 23 – 96). By BMI category, 25 were normal or underweight, 65 overweight, and 51 obese – of which 19 were morbidly obese. Only 11 men had known BRCA1/2 mutations. Median age at diagnosis was 69 in normal/underweight men versus 63 in obese men and 51 in morbidly obese men (P≤0.05). Among those with invasive tumors, average tumor size was 1.50 cm (± 0.84) in normal/underweight men versus 2.04 (±0.81) in morbidly obese men (P≤0.05). Archived breast tissue was available from 92 (65%) men. Breast adipose inflammation was present in 55 (60%) men, and average BMI was 31 (±8) versus 28 (±5) in men with versus without inflammation, respectively (P=0.07). Conclusions: Obesity is associated with early onset breast cancer in men. Morbidly obese men were diagnosed with breast cancer at an even younger age and had larger tumors than normal weight individuals. These findings support further studies to investigate mechanisms, such as adipose inflammation, through which obesity may promote breast cancer in men. Citation Format: Williams S, Parrish JC, Zhou XK, Wang H, Dierickx A, Gucalp A, Dannenberg AJ, Iyengar NM. Obesity and adipose inflammation in men with breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-04.

In our biochemistry course we provide multiple choice questions in PDF format. Recently, we decided to use an online game. To explore possible advantages of this approach, we compared students’ attitudes towards questions in online game or PDF format. Students had access to either the PDF or the online game. Feedback was collected using a survey and analyzed by item analysis. Open‐ended comments were also solicited. The comments were grouped as either positive or negative and then categorized. The number and nature of the comments in each category was compared for the two groups. Item analysis showed that the questions were perceived as equally valuable by both groups. However, the comments revealed notable differences in attitude. The game‐users submitted a greater proportion of negative comments (71%) than PDF users (39%). The negative comments revealed that game users complained more frequently about technical difficulties, and PDF users complained more frequently about question content and errors. The positive comments revealed that both groups felt the questions helped them in exams. However, only game users reported that the format was ‘engaging and fun.’ Overall, our students valued the questions provided, regardless of format. However, those using the game and PDF formats reported quite different negative and positive attitudes, which likely impact the function of the practice questions as a learning tool.

The 3C-like proteinase (3CL(pro)) of severe acute respiratory syndrome (SARS) coronavirus is a key target for structure-based drug design against this viral infection. The enzyme recognizes peptide substrates with a glutamine residue at the P1 site. A series of keto-glutamine analogues with a phthalhydrazido group at the alpha-position were synthesized and tested as reversible inhibitiors against SARS 3CL(pro). Attachment of tripeptide (Ac-Val-Thr-Leu) to these glutamine-based "warheads" generated significantly better inhibitors (4a-c, 8a-d) with IC(50) values ranging from 0.60 to 70 microM.

This analysis of the title compound, C13H13F2IO3, establishes the orientation of (E)-5-(CH=CH-I) as antiperiplanar (ap) to the C-C bond (5-6 position) of the 2,4-difluorophenyl ring system, with the (E)-5-(CH=CH-I) H atom located in close proximity (2.17 A) to the F4 atom of the 2,4-difluorophenyl moiety.

This analysis establishes the rotameric orientation of the pyridyl-ring N atom of the title compound, C17H21N3O4. 0.5C(6)H(6), as antiperiplanar (ap) to the 1,4-dihydropyridine H-4, the absence of an intramolecular hydrogen bond between the 1,4-dihydropyridine NH and the pyridyl-N atom, and the unusual planarity of the 1,4-dihydropyridine ring.

Mouse granzyme B is a member of the chymotrypsin family of serine proteinases that has an unusual preference for cleavage of substrates following aspartate residues. We show here that granzyme B can be redesigned by a single amino acid substitution in one wall of the specificity pocket, arginine-226 to glutamate, to hydrolyze preferentially thioester substrates following basic amino acids. Amide substrates, however, were not hydrolyzed by the variant granzyme B. These results show that residue 226 is a primary determinant of granzyme B specificity and imply that additional structural components are required for catalysis of amide bonds. Molecular modeling indicated subtle variation in glutamate-226 orientation depending upon the state of protonation of the gamma-carboxylate, which may account for the secondary specificity of this enzyme for substrates containing phenylalanine. This represents the first example of electrostatic reversal of serine proteinase substrate specificity and suggests that residue 226 is a primary substrate specificity determinant in the granzyme B lineage of serine proteinases.

The design of inhibitors with enhanced potency against proteolytic enzymes has many applications for the treatment of human diseases. In addition to the optimization of chemical interactions between the enzyme and inhibitor, the binding affinity can be increased by constraining the inhibitor to the conformation that is recognized by the enzyme, thus lowering the entropic barrier to complex formation. We have structurally characterized the complexes of a macrocyclic pentapeptide inhibitor and its acyclic analogue with penicillopepsin, an aspartic proteinase, to study the effect of conformational constraint on the binding affinity. The phosphonate-based macrocycle PPi4 (Ki = 0.10 nM) is covalently linked at the P2-Asn and P1'-Phe side chains [nomenclature of Schechter and Berger, Biochim. Biophys. Res. Commun. (1967) 27, 157-162] via an amide bond, relative to the acyclic compound PPi3 (Ki = 42 nM). Comparisons of the high-resolution crystal structures of PPi4-penicillopepsin (0.95 A) and PPi3-penicillopepsin (1.45 A) reveal that the conformations of the inhibitors and their interactions with the enzyme are similar. The 420-fold increase in the binding affinity of PPi4 is attributed to a reduction in its conformational flexibility, thus providing the first rigorous measure of the entropic contribution to the binding energy in a protein-ligand complex and stressing the advantages of the design strategy.