Gelatin nonwovens-based epithelial morphogenesis involves a signaling axis comprising EGF-receptor, MAP kinases ERK 1/2, and β1 integrin

In biomaterials research, biomechanics which support tissue regeneration steadily gains of importance. Hence, we have previously shown that gelatin-based electrospun nonwoven mats (NWMs) with a distinct modulus of elasticity (3.2 kPa) promotes epithelial morphogenesis. Since molecular mechanisms of this morphogenesis are still unknown, the present study aims at identifying molecules, involved herein. Epithelia established on the NMWs showed persistence of the activated state of the epidermal growth factor receptor (EGF-R), phosphorylated at the src-specific tyrosine 845 (EGF-R_T845 ) throughout the observation period of 10 days. To elucidate whether the observed morphogenesis mechanistically involves EGF-R signaling, we inhibited EGF-R, by employing the EGF-R_T845 specific inhibitor Gefitinib (IRESSA®). Gefitinib administration yielded a reduced expression of the β1 integrin subunit, a well-known cell-matrix interaction receptor, concomitant with downregulation of p42/44 ERK1/2 MAP-kinase activity. To elucidate whether the observed downregulation of β1 is EGF-R_T845 -dependent or emerging from ERK1/2 signaling, we exposed epithelia, grown on the NWMs, with the ERK1/2-directed inhibitor U0126. In the absence of Gefitinib, inhibition of p42/44 MAP-kinase activity resulted in decreased β1 integrin protein levels, thus indicating that β1 expression is dependent on ERK1/2 and not EGF-R_T845 . Our results showed the first time that an EGF-R-β1 integrin-signaling axis, including ERK1/2, promotes NWM-elasticity-based epithelial morphogenesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 663-677, 2019.

What Affects Clinicians' Usage of Health Information Exchange?

BACKGROUND: The ability to electronically exchange health information among healthcare providers holds enormous promise to improve care coordination and reduce costs. Provider-to-provider data exchange is an explicit goal of the American Recovery and Reinvestment Act of 2009 and may be essential for the long-term success of the Affordable Care Act of 2010. However, little is known about what factors affect clinicians' usage of health information exchange (HIE) functionality. OBJECTIVE: To identify factors that affect clinicians' HIE usage - in terms of frequency of contributing data to and accessing data from aggregate patient records - and suggest policies for fostering its usage. METHODS: We performed a qualitative study using grounded theory by interviewing clinician-users and HIE staff of one operational HIE which supported aggregate patient record functionality. Fifteen clinicians were interviewed for one hour each about what factors affect their HIE usage. Five HIE staff were asked about technology and training issues to provide context. Interviews were recorded, transcribed and analyzed. Recruitment excluded clinicians with little or no familiarity with the HIE and was restricted to one community and a small number of specialties. RESULTS: Clinicians were motivated to access the HIE by perceived improvements in care quality and time savings, but their motivation was moderated by an extensive list of factors including gaps in data, workflow issues and usability issues. HIE access intensities varied widely by clinician. Data contribution intensities to the HIE also varied widely and were affected by billing concerns and time constraints. CONCLUSIONS: Clinicians, EHR and HIE product vendors and trainers should work toward integrating HIE into clinical workflows. Policies should create incentives for HIE organizations to assist clinicians in using HIE, develop measures of HIE contributions and accesses, and create incentives for clinicians to contribute data to HIEs.

Application of the singular perturbation method to reaction kinetics

The purpose of this paper is to show how to apply the singular perturbation method to the rate equations in reaction kinetics that involve different time scales. The Lindemann scheme has been chosen for illustration, and the steady-state and equilibrium approximations used in the Lindemann scheme are discussed.

Stochastic Model of Unimolecular Reactions and the RRKM Theory

A stochastic model of unimolecular reactions has been adopted for investigation of the validity and limitation of the RRKM theory. The error caused by the steady-state approximation for distribution of energized molecules is small, while the assumption of the internal energy equilibration of energized molecules might cause serious errors for reactions of low activation energies.

Antitumor activity, and antiangiogenic activity of nanoparticle albumin-bound nab-rapamycin in combination with nab-paclitaxel

Abstract #3125

Background: Rapamycin inhibits downstream signals from the mammalian target of rapamycin (mTOR), a known kinase member of a signaling pathway that promotes tumor growth. Rapamycin's poor aqueous solubility and poor chemical stability have limited its development as an intravenous (IV) anticancer agent. Nab-rapamycin utilizes the albumin-bound technology to allow for IV administration of rapamycin and has demonstrated dose-linear pharmacokinetics and safety up to 90 mg/kg with effective antitumor activity at 40 mg/kg against a human panel of tumor xenografts. This study investigated the efficacy of combined therapy with nab-paclitaxel (Abraxane®) utilizing invasive human breast (MDA-MB-231) and colon (HT29) cancer xenograft models.
 Material and Methods: Xenograft transplants using luciferase-tagged MDA-MB-231 cells were implanted into mammary fatpad of SCID mice and allowed to reach 460 mm3 in size prior to IV administration of saline (vehicle, n = 9); nab-rapamycin, 3x wkly for 2 wks at 40 mg/kg (nab-rap-2W; n = 8); nab-rapamycin, 3x wkly for 4 wks at 40 mg/kg (nab-rap-4W; n = 8); Abraxane, qdx5 at 30 mg/kg (ABX; n = 8); nab-rap-2W + ABX (n = 9); or nab-rap-4W + ABX (n = 8). HT29 xenografts were also treated with nab-rap-4W (n = 8) and nab-rap-4W + ABX (10 mg/kg, qdx5, IP, n = 8). The in vivo antiangiogenic effect of nab-rapamycin was evaluated using the standard in vivo chick chorioallantoic membrane (CAM) assay with 3-day old embryos (n = 18).
 Results: Relative to vehicle controls, nab-rap-2W (P < 0.00011), nab-rap-4W (P < 0.0001), and ABX (P < 0.0001) were effective against MDA-MB-231 tumor xenograft models with tumor growth inhibition (TGI) of 60%, 66%, and 73% respectively. Additive antitumor effects were observed with combination of nab-rapamycin + ABX with TGI of 81% and 86% for nab-rap-2W + ABX and nab-rap-4W + ABX groups, respectively. For HT29 tumors, the combination of ABX and nab-rapamycin also showed greater TGI (89%) compared to nab-rapamycin alone (81%). In the chick CAM assay, nab-rapamycin demonstrated antiangiogenic efficacy at doses of 10 µg and above without affecting embryo viability.
 Conclusions: Combination therapy of nab-rapamycin and Abraxane was more effective at inhibiting breast and colon xenograft tumor growth than single therapy of either drug. The enhanced antitumor activity seen with combined nab-rapamycin-Abraxane may in part be due to the observed antiangiogenic activity of nab-rapamycin.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3125.

Mechanisms of nab-paclitaxel and bevacizumab cooperation in inhibition of breast tumor growth and metastasis

Abstract #1032

Background: Nab-paclitaxel, also known as Abraxane®, is paclitaxel formulated in nanoparticles that consist of human albumin encapsulating the hydrophobic drug moiety. This drug has shown numerous advantages including linear pharmacokinetics, significantly higher tumor retention, and increased maximal-tolerated dose due to reduced toxicity. We previously showed that combination of Abraxane and anti-VEGF-A antibody, bevacizumab, is significantly more efficacious in suppression of breast tumor xenografts and metastasis as compared to treatments with each of these drugs alone. We hypothesized that the mechanism underlying the therapeutic success of the combined therapy might include bevacizumab-dependent abrogation of the stress response elicited by paclitaxel in the tumor cells surviving chemotherapy.
 Materials and Methods: Cultured MDA-MB-231 cells were treated with 0, 2.5, 5, 10, and 30 nM of Abraxane followed by detection of angiogenic (VEGF-A), prosurvival (p42 & p44 kinase, bcl-2) and inflammatory (IL-6, IL-8, and TNF-α) proteins using Western blotting and ELISA. MDA-MB-231 tumors were extracted from mice upon cessation of intravenous (IV) Abraxane therapy (10 to 30 mg/kg, qdx5) followed by Western blot and immunohistochemical analyses.
 Results: In vitro, Abraxane treatment increased expression of VEGF-A, p42/44 kinase, bcl-2 as well as total and phosphorylated p65 subunit of NF-κB. Treated cells secreted 25- to 30-fold higher concentrations of inflammatory cytokines IL-6, IL-8, and TNF-α into conditioned media as compared with untreated control cells. Likewise, significant increases in bcl-2 and inflammatory cytokines were observed in tumors extracted immediately after paclitaxel therapy in vivo as confirmed by both Western blotting and immunohistochemical analyses.
 Discussion: These findings suggest that paclitaxel elicits VEGF-A dependent prosurvival and proinflammatory stress responses in tumor cells surviving the cytotoxic therapy. Activation of these pathways suggests that concurrent therapy with VEGF-A neutralizing antibody might significantly improve the efficacy of paclitaxel-based therapies by counteracting the stress responses in the therapy-spared tumor cells.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1032.

Keeping patients active and current in a patient portal

Maintaining current contact information is crucial to the effectiveness of communication via patient portals. Patients who visit a portal infrequently, or whose contact information is not updated, may miss administrative notices or clinical messages from their doctor's office. We invited patients to review and update their contact information via a broadcast e-mail message sent to all patients in the patient portal, Patient Gateway. We report the effectiveness of the broadcast message approach to reaching registered patients.

The molecular chaperone Hsp90 is required for signal transduction by wild-type Hck and maintenance of its constitutively active counterpart

We have investigated the relationship between the molecular chaperone heat shock protein-90 (Hsp90) and the signal transducing capacity of the Src-family kinase Hck. Inhibition of Hsp90 with geldanamycin suppressed the ability of bacterial lipopolysaccharide to enhance the cell adhesion properties of macrophages, a phenomenon most likely explained by the reduced expression and activity of Hck in macrophages lacking Hsp90 function. The contribution of Hsp90 to signal transduction by Hck was biochemically dissected further by examining its role in the de novo folding and maintenance of wild-type Hck and its constitutively active counterpart, Hck499F. The folding of nascent wild-type Hck and Hck499F into catalytically active conformations, and their accumulation in cells was found to be dependent on Hsp90 function. Notably, mature Hck499F had a greater requirement for on-going support from Hsp90 than did mature wild-type Hck. This particular finding might have important implications for our understanding of the evolution of oncogenic protein kinases.

p50(cdc37) is a nonexclusive Hsp90 cohort which participates intimately in Hsp90-mediated folding of immature kinase molecules

Hsp90 and p50(cdc37) provide a poorly understood biochemical function essential to certain protein kinases, and recent models describe p50(cdc37) as an exclusive hsp90 cohort which links hsp90 machinery to client kinases. We describe here the recovery of p50(cdc37) in immunoadsorptions directed against the hsp90 cohorts FKBP52, cyp40, p60HOP, hsp70, and p23. Additionally, monoclonal antibodies against FKBP52 coadsorb maturation intermediates of the hsp90-dependent kinases p56(lck) and HRI, and the presence of these maturation intermediates significantly increases the representation of p50(cdc37) and hsp90 on FKPB52 machinery. Although the native heterocomplex between hsp90 and p50(cdc37) is salt-labile, their dynamic interactions with kinase substrates produce kinase-chaperone heterocomplexes which are highly salt-resistant. The hsp90 inhibitor geldanamycin does not directly disrupt the native association of hsp90 with p50(cdc37) per se, but does result in the formation of salt-labile hsp90-kinase heterocomplexes which lack the p50(cdc37) cohort. We conclude that p50(cdc37) does not simply serve as a passive structural bridge between hsp90 and its kinase substrates; instead, p50(cdc37) is a nonexclusive hsp90 cohort which responds to hsp90's nucleotide-regulated conformational switching during the generation of high-affinity interactions within the hsp90-kinase-p50(cdc37) heterocomplex.