4 research outputs found
Enzymes Photo-Cross-Linked to Live Cell Receptors Retain Activity and EGFR Inhibition after Both Internalization and Recycling
No full textIn this work, we show that a prodrug enzyme covalently
photoconjugated
to live cell receptors survives endosomal proteolysis and retains
its catalytic activity over multiple days. Here, a fusion protein
was designed with both an antiepidermal growth factor receptor (EGFR)
affibody and the prodrug enzyme cytosine deaminase, which can convert
prodrug 5-fluorocytosine to the anticancer drug 5-fluorouracil. A
benzophenone group was added at a site-specific mutation within the
affibody, and the fusion protein was selectively photoconjugated to
EGFR receptors expressed on membranes of MDA-MB-468 breast cancer
cells. The fusion protein was next labeled with two dyes for tracking
uptake: AlexaFluor 488 and pH-sensitive pHAb. Flow cytometry showed
that fusion proteins photo-cross-linked to EGFR first underwent receptor-mediated
endocytosis within 12 h, followed by recycling back to the cell membrane
within 24 h. These findings were also confirmed by confocal microscopy.
The unique cross-linking of the affibody-enzyme fusion proteins was
utilized for two anticancer treatments. First, the covalent linking
of the protein to the EGFR led to inhibition of ERK signaling over
a two-day period, whereas conventional antibody therapy only led to
6 h of inhibition. Second, when the affibody-CodA fusion proteins
were photo-cross-linked to EGFR overexpressed on MDA-MB-468 breast
cancer cells, prodrug conversion was found even 48 h postincubation
without any apparent decrease in cell killing, while without photo-cross-linking
no cell killing was observed 8 h postincubation. These studies show
that affinity-mediated covalent conjugation of the affibody-enzymes
to cell receptors allows for prolonged expression on membranes and
retained enzymatic activity without genetic engineering
Incident gout and chronic Kidney Disease: healthcare utilization and survival
No full textAbstract Background Uncontrolled gout can cause significant joint and organ damage and has been associated with impairments in quality of life and high economic cost. Gout has also been associated with other comorbid diseases, such as chronic kidney disease. The current study explored if healthcare resource utilization (HRU) and survival differs between patients with incident gout in the presence or absence of chronic kidney disease (CKD). Methods Clalit Health Services (CHS) data were used to conduct a retrospective population-based cohort study of incident gout between 1/1/2006–31/12/2009. Incident cases of gout were identified and stratified by CKD status and by age group (< 55 and 55+ years). CKD status was defined as a pre-existing diagnosis of chronic kidney disease, chronic renal failure, kidney transplantation, or dialysis at index date. Demographic and clinical characteristics, as well as healthcare resource use, were reported. Results A total of 12,940 incident adult gout patients, with (n = 8286) and without (n = 4654) CKD, were followed for 55,206 person-years. Higher rates of HRU were observed for gout patients with CKD than without. Total annual hospital admissions for patients with gout and CKD were at least 3 times higher for adults < 55 (mean = 0.51 vs 0.13) and approximately 1.5 times higher for adults 55+ (mean = 0.46 vs 0.29) without CKD. Healthcare utilization rates from year 1 to year 5 remained similar for gout patients < 55 years irrespective of CKD status, however varied according to healthcare utilization by CKD status for gout patients 55+ years. The 5-year all-cause mortality was higher among those with CKD compared to those without CKD for both age groups (HR< 55 years = 1.65; 95% CI 1.01–2.71; HR55+ years = 1.50; 95% CI 1.37–1.65). Conclusions The current study suggests important differences exist in patient characteristics and outcomes among patients with gout and CKD. Healthcare utilization differed between sub-populations, age and comorbidities, over the study period and the 5-year mortality risk was higher for gout patients with CKD, regardless of age. Future work should explore factors associated with these outcomes and barriers to gout control in order to enhance patient management among this high-risk subgroup
