TGF-ß Mediated Immune Evasion in Cancer-Spotlight on Cancer-Associated Fibroblasts.

Various components of the tumor microenvironment (TME) play a critical role in promoting tumorigenesis, progression, and metastasis. One of the primary functions of the TME is to stimulate an immunosuppressive environment around the tumor through multiple mechanisms including the activation of the transforming growth factor-beta (TGF-ß) signaling pathway. Cancer-associated fibroblasts (CAFs) are key cells in the TME that regulate the secretion of extracellular matrix (ECM) components under the influence of TGF-ß. Recent reports from our group and others have described an ECM-related and CAF-associated novel gene signature that can predict resistance to immune checkpoint blockade (ICB). Importantly, studies have begun to test whether targeting some of these CAF-associated components can be used as a combinatorial approach with ICB. This perspective summarizes recent advances in our understanding of CAF and TGF-ß-regulated immunosuppressive mechanisms and ways to target such signaling in cancer.

Covalent Immobilization of Protein A on Chitosan and Aldehyde Double-Branched Chitosan as Biocompatible Carriers for Immunoglobulin G (Igg) Purification.

High-affinity ligands, such as protein A, can be used to develop biocompatible matrices for antibody purification. In this paper, two methods were used for immobilization of protein A on the chitosan. In the first approach, amino groups of chitosan beads were functionalized with tris(2-aminoethyl)amine to produce amine double-branched moieties, which were subsequently activated with glutaraldehyde. In the second approach, chitosan beads were directly modified by glutaraldehyde to produce aldehyde groups. Structural characterization and successful modification of the functional groups on the supports were confirmed by scanning electron microscopy, FTIR spectroscopy and elemental analysis. Covalent immobilization of protein A was then performed on the surface of both supports. The immobilization yield was determined by using fluorescence spectroscopy, showing almost 15% increased capacity for the double-branched derivatized chitosan. The Immunoglobulin G (IgG) purification ability of the double-branched support was also almost 1.7-fold higher than the monoaldehyde derivative at the same condition.

Designing a novel signal sequence for efficient secretion of Candida antarctica lipase B in E. coli: The molecular dynamic simulation, codon optimization and statistical analysis approach.

Lipases represent an important industrial biocatalysts group displaying enantioselectivity, high stability in solvents and substrate specificity. A commonly used commercial enzyme for synthesis of organic materials is Candida antarctica lipase B (CALB). Its Industrial production involves cost-effective purification of large amounts of microbially-produced macromolecules. Hence, great focus is now placed on periplasmic secretion and storage. Accordingly, we designed and constructed a suitable signal peptide for secretion of lipase using a newly developed software. Molecular dynamic simulation was performed to compare structural states of native signal peptide of Staphylococcus aureus protein A (nSpA) and its modified counterpart (mSpA). Furthermore, the effect of these two peptides in binding to the signal peptidase I (SPase I) was studied. Simulation data confirmed experimental results showing that secondary structure of the mSpA binding region and the binding site of the SPase I create a more stable interaction relative to native SpA. Subsequently, response surface methodology (RSM) was employed to improve secretion. Lactose concentration, induction time and temperature were identified as essential parameters to optimize the expression and periplasmic secretion of CALB. mSpA increased CALB expression levels by 2.1-fold relative to the control, which further confirmed efficient secretion of the mature enzyme through the Sec-dependent pathway.