Human elastin-like polypeptides as a versatile platform for exploitation of ultrasensitive bilirubin detection by UnaG.

A new, bifunctional recombinant protein was expressed as the fusion product of human elastin-like polypeptide (HELP) and the bilirubin-binding protein UnaG. The engineered product displays both the HELP-specific property of forming a functional hydrogel matrix and the UnaG-specific capacity of emitting green fluorescence upon ligand binding. The new fusion protein has been proven to be effective at detecting bilirubin in complex environments with high background noise. A cell culture model of the stress response, consisting of bilirubin released in the cell culture medium, was set up to assess the bilirubin-sensing properties of the functional matrix obtained by cross-linking the HELP moiety. Our engineered protein allowed us to monitor cell induction by the release of bilirubin in the culture medium on a nanomolar scale. This study shows that elastin-like protein fusion represents a versatile platform for the development of novel and commercially viable analytical and biosensing devices.

Oncogenic and Non-Malignant Pancreatic Exosome Cargo Reveal Distinct Expression of Oncogenic and Prognostic Factors Involved in Tumor Invasion and Metastasis.

Exosomes are small extracellular membrane vesicles important in intercellular communication, with their oncogenic cargo attributed to tumor progression and pre-metastatic niche formation. To gain an insight into key differences in oncogenic composition of exosomes, human non-malignant epithelial and pancreatic cancer cell models and purified and characterized resultant exosome populations are utilized. Proteomic analysis reveals the selective enrichment of known exosome markers and signaling proteins in comparison to parental cells. Importantly, valuable insights into oncogenic exosomes (362 unique proteins in comparison to non-malignant exosomes) of key metastatic regulatory factors and signaling molecules fundamental to pancreatic cancer progression (KRAS, CD44, EGFR) are provided. It is reported that oncogenic exosomes contain factors known to regulate the pre-metastatic niche (S100A4, F3, ITGß5, ANXA1), clinically-relevant proteins which correlate with poor prognosis (CLDN1, MUC1) as well as protein networks involved in various cancer hallmarks including proliferation (CLU, CAV1), invasion (PODXL, ITGA3), metastasis (LAMP1, ST14) and immune surveillance escape (B2M). The presence of these factors in oncogenic exosomes offers an understanding of select differences in exosome composition during tumorigenesis, potential components as prognostic and diagnostic biomarkers in pancreatic cancer, and highlights the role of exosomes in mediating crosstalk between tumor and stromal cells.

Molecularly imprinted electrochemical sensor for the ultrasensitive detection of cytochrome c.

Cytochrome c (Cyt c) is an important biomarker for the early stage of apoptosis that plays a role in the diagnosis and therapy of several diseases including cancer. Here, an electrochemical sensor based on molecularly imprinted polymer (MIP) for the ultrasensitive detection of Cyt c is studied. It is prepared by electropolymerization of o-phenylenediamine in the presence of Cyt c as template, followed by solvent extraction, resulting in the formation of Cyt c recognition sites. The MIP is characterised by cyclic voltammetry and differential pulse voltammetry, using ferrocenecarboxylic acid as redox probe. Voltammetric data indicates that the MIP-sensor behaves as an electrode with partially blocked surface. The partition isotherm obtained fits the Langmuir model, indicating a high affinity for Cyt c, with an association constant Ka = 5 × 10 11 M-1. DPV measurements allow to achieve extremely high analytical sensitivity and low detection limit, in the femtomolar range, with negligible unspecific adsorption. Satisfactory analytical recovery tests performed in the presence of possible interfering proteins and in diluted human serum confirmed the selectivity of the MIP-sensor as well as its potential applicability for real samples analysis.

Successful Preservation of Native BCR::ABL1 in Chronic Myeloid Leukemia Primary Leukocytes Reveals a Reduced Kinase Activity.

Chronic myeloid leukemia (CML) is a myeloproliferative disease caused by the acquisition of t(9;22) generating the fusion tyrosine kinase BCR::ABL1. However, despite the crucial role of this protein in the dysregulation of numerous signal transduction pathways, a direct measure of BCR::ABL1 kinase activity in chronic phase (CP) CML was never accomplished due to intense degradative activity present in mature leukocytes. Therefore, we developed a procedure suitable to preserve BCR::ABL1 protein under non-denaturing, neutral pH conditions in primary, chronic phase (CP)-CML samples. As a result, specific kinase activity was detected utilizing a biotinylated peptide substrate highly selective for c-ABL1. Furthermore, through this approach, BCR::ABL1 kinase activity was barely detectable in CP-CML compared to Ph+ acute lymphoblastic leukemia primary samples, where kinase activity is comparable to those measured in Ph+ cell lines. These in vitro findings provide the first direct measure of BCR::ABL1 kinase activity in primary CP-CML and reveal the presence of a still uncharacterized inhibitory mechanism that maintains BCR::ABL1 in a low activity state in CP-CML despite its overexpression.

Targeting Kinase-activating Genetic Lesions to Improve Therapy of Pediatric Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children, characterized by an abnormal proliferation of immature lymphoid cells. Thanks to risk-adapted combination chemotherapy treatments currently used, survival at 5 years has reached 90%. ALL is a heterogeneous disease from a genetic point of view: patients' lymphoblasts may harbor in fact several chromosomal alterations, some of which have prognostic and therapeutic value. Of particular importance is the translocation t(9;22)(q34;q11.2) that leads to the formation of the BCR-ABL1 fusion gene, encoding a constitutively active chimeric tyrosine kinase (TK): BCR-ABL1 that is present in ~3% of pediatric ALL patients with B-immunophenotype and is associated with a poor outcome. This type of ALL is potentially treatable with specific TK inhibitors, such as imatinib. Recent studies have demonstrated the existence of a subset of BCR-ABL1 like leukemias (~10-15% of Bimmunophenotype ALL), whose blast cells have a gene expression profile similar to that of BCR-ABL1 despite the absence of t(9;22)(q34;q11.2). The precise pathogenesis of BCR-ABL1 like ALL is still to be defined, but they are mainly characterized by the activation of constitutive signal transduction pathways due to chimeric TKs different from BCR-ABL1. BCR-ABL1 like ALL patients represent a group with unfavorable outcome and are not identified by current risk criteria. In this review, we will discuss the design of targeted therapy for patients with BCR-ABL1 like ALL, which could consider TK inhibitors, and discuss innovative approaches suitable to identify the presence of patient's specific chimeric TK fusion genes, such as targeted locus amplification or proteomic biosensors.