Therapeutic proteins have increasingly been used in modern medical applications, but their effectiveness is limited by factors such as stability and blood circulation time. Recently, there has been significant research into covalently linking polyethylene glycol polymer chains (PEG) to proteins, known as PEGylation, to mitigate these issues. In this work, an atomistic molecular dynamics study of N-terminal conjugated PEG-BSA (bovine serum albumin) was conducted with varying PEG molecular weights (2, 5, 10, and 20 kDa) to probe PEG-BSA interactions and evaluate the effect of polymer length on dynamics. It was found that the affinity of PEG toward the protein surface increased as a function of PEG molecular weight and that a certain weight (around 10 kDa) was required to promote protein–polymer interactions. Additionally, preferential interactions were monitored through formed contacts and hotspots were identified. PEG chains coordinating in looplike conformations were found near lysine residues. Also, it was found that hydrophobic interactions played an important role in promoting PEG-BSA interactions as the PEG molecular weight increased. The results provide insight into underlying mechanisms behind transitions in PEG conformations and will aid in future design of effective PEGylated drug molecules.

The conjugation of polyethylene glycol (PEG) to proteins, known as PEGylation, has increasingly been employed to expand the efficacy of therapeutic drugs.

Macromolecules such as proteins conjugated to polyethylene glycol (PEG) have been employed in therapeutic drug applications, and recent research has emphasized the potential of varying polymer architectures and conjugation strategies to achieve improved efficacy. In this study, we performed atomistic molecular dynamics simulations of bovine serum albumin (BSA) conjugated to 5 kDa PEG polymers in an array of schemes, including varied numbers of attached chains, grafting density, and nonlinear architectures. Nonlinear architectures included U-shaped PEG, Y-shaped PEG, and poly(oligoethylene glycol methacrylate) (POEGMA). Buried surface area calculations and polymer volume map analyses revealed that volume exclusion behaviors of the high grafting density conjugate promoted additional protein–polymer interactions when compared to simply increasing numbers of conjugated chains uniformly across the protein surface. Investigation of nonlinear polymer architectures showed that stable polymer-lysine loop-like conformations seen in previous conjugate designs were more variable in prevalence, especially in POEGMA, which contained short oligomer PEG chains. The findings of this comprehensive study of alternate PEGylation schemes of BSA provide critical insight into molecular patterns of interaction within bioconjugates and highlight their importance in the future of controlled modification of conjugate system parameters.

e16306 Background: Duodenal adenocarcinoma (DA) is a rare malignancy with poor outcomes. Tumor markers are used to assess disease response and to monitor for recurrence. Specifically, CA-19-9 and CEA have been validated for use in pancreatic cancer and colorectal cancer, respectively. However, these tumor markers have never been validated in patients with DA. We aim to assess the association of these biomarkers with clinical outcomes in patients with DA. Methods: This is a retrospective cohort study. After obtaining IRB approval (IRB202102705), we accessed the University of Florida medical records of patient treated for DA from January 1, 2006, until December 31, 2021. CA 19-9 and CEA were collected as continuous variables and were analyzed as binary variables: normal vs. high, using the maximum normal value as a cut-off (normal CA 19-9 < = 35 U/ml; CEA < = 3 ng/ml). Analysis was conducted using Kaplan Meyer curves, log-rank test and Cox proportional hazards model. Results: A total of 68 patients were included in the final analysis. Median age was 67 years and median follow-up was 22.2 months. CA 19-9 and CEA were elevated in 36.8% and 48.5% of patients, respectively. Patients with an elevated CA 19-9 had a median overall survival (OS) of 8.5 months vs. 27.4 months in patients with normal levels (HR 1.67; 95%CI 0.94–2.99; p = 0.081). Patients with an elevated CEA had a median OS of 13.4 months vs. 16.8 months in patients with normal level normal levels (HR 1.43; 95%CI 0.81–2.52; p value = 0.221). In a sensitivity analysis, a concomitant elevation of both tumoral markers was significantly associated with worsened OS (HR 1.9; 95%CI 1.05–3.06; p = 0.035). Conclusions: In patients with duodenal adenocarcinoma, elevation of both CA 19-9 and CEA was associated with a statistically significant worse overall survival. CA 19-9 level had a higher prognostic impact on OS than CEA levels. To our knowledge, this is the first study to evaluate the role of CA 19-9 and CEA in patients with DA. Further research is required for validation.[Table: see text]