Functionalized Poly(N-isopropylacrylamide)-Based Microgels in Tumor Targeting and Drug Delivery

Over the past several decades, the development of engineered small particles as targeted and drug delivery systems (TDDS) has received great attention thanks to the possibility to overcome the limitations of classical cancer chemotherapy, including targeting incapability, nonspecific action and, consequently, systemic toxicity. Thus, this research aims at using a novel design of Poly(N-isopropylacrylamide) p(NIPAM)-based microgels to specifically target cancer cells and avoid the healthy ones, which is expected to decrease or eliminate the side effects of chemotherapeutic drugs. Smart NIPAM-based microgels were functionalized with acrylic acid and coupled to folic acid (FA), targeting the folate receptors overexpressed by cancer cells and to the chemotherapeutic drug doxorubicin (Dox). The successful conjugation of FA and Dox was demonstrated by dynamic light scattering (DLS), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), UV-VIS analysis, and differential scanning calorimetry (DSC). Furthermore, viability assay performed on cancer and healthy breast cells, suggested the microgels’ biocompatibility and the cytotoxic effect of the conjugated drug. On the other hand, the specific tumor targeting of synthetized microgels was demonstrated by a co-cultured (healthy and cancer cells) assay monitored using confocal microscopy and flow cytometry. Results suggest successful targeting of cancer cells and drug release. These data support the use of pNIPAM-based microgels as good candidates as TDDS.

IL-8 secreted by tumor associated macrophages contribute to lapatinib resistance in HER2-positive locally advanced breast cancer via activation of Src/STAT3/ERK1/2-mediated EGFR signaling

Locally advanced breast cancer (LABC) is an aggressive disease characterized by late clinical presentation, large tumor size, treatment resistance and low survival rate. Expression of EGFR/HER2 and activation of intracellular tyrosine kinase domains in LABC are associated with poor prognosis. Thus, target therapies such as the anti-receptor tyrosine kinases lapatinib drug have been more developed in the past decade. The response to lapatinib involves the inhibition of RTKs and subsequently signaling molecules such as Src/STAT3/Erk1/2 known also to be activated by the cytokines in the tumor microenvironment (TME). The aim of the present study is to identify the major cytokine that might contribute to lapatinib resistance in EGFR+/HER2+ LABC patients. Indeed, tumor associated macrophages (TAMs) are the main source of cytokines in the TME. Herein, we isolated TAMs from LABC during modified radical mastectomy (MRM). Cytokine profile of TAMs revealed that IL-8 is the most prominent highly secreted cytokine by TAMs of LABC patients. Using in-vitro cell culture model we showed that recombinant IL-8 (50 and 100 ng/mL) at different time intervals interfere with lapatinib action via activation of Src/EGFR and signaling molecules known to be inhibited during treatment. We proposed that to improve LABC patients' response to lapatinib treatment it is preferred to use combined therapy that neutralize or block the action of IL-8.

Purification and immobilization of L-arginase from thermotolerant Penicillium chrysogenum KJ185377.1; with unique kinetic properties as thermostable anticancer enzyme

L-Arginase, hydrolyzing L-arginine to L-ornithine and urea, is a powerful anticancer, L-arginine-depleting agent, against argininosuccinate synthase expressing tumors. Otherwise, the higher antigenicity and lower thermal stability of this enzyme was the main biochemical hurdles. Since, the intrinsic thermal stability of enzymes follow the physiological temperature of their producer, thus, characterization of L-arginase from thermotolerant Penicillium chrysogenum was the objective of this study. L-Arginase (Arg) was purified to its homogeneity from P. chrysogenum by 10.1-fold, with 37.0 kDa under denaturing PAGE, optimum reaction at 50 °C, pH stability (6.8-7.9), with highest molar ratio of constitutional arginine, glutamic acid, lysine and aspartic acid. The purified enzyme was PEGylated and immobilized on chitosan, with 41.9 and 22.1 % yield of immobilization. At 40 °C, the T1/2 value of free-Arg, PEG-Arg and Chit-Arg was 10.4, 15.6, 20.5 h, respectively. The free-Arg and Chit-Arg have a higher affinity to L-arginine (K m 4.8 mM), while, PEG-Arg affinity was decreased by about 3 fold (K m 15.2 mM). The inhibitory constants to the free and PEG-Arg were relatively similar towards HA and PPG. The IC50 for the free enzyme against HEPG-2 and A549 tumor cells was 0.136 and 0.165 U/ml, comparing to 0.232 and 0.496 U/ml for PEG-Arg, respectively. The in vivo T1/2 to the free Arg and PEG-Arg was 16.4 and 20.4 h, respectively as holo-enzyme. The residual L-arginine level upon using free Arg was 156.9 and 144.5 µM, after 6 and 8 h, respectively, regarding to initials at 253.6 µM, while for Peg-Arg the level of L-arginine was nil till 7 h of initial dosing. The titer of IgG was induced by 10-15 % in response to free-Arg after 28 days comparing to IgG titer for PEG-Arg.

Construction of genetic linkage map with chromosomal assigment and quantitative trait loci associated with some important agronomic traits in cotton

Cotton is the world's leading natural fiber and second most important oilseed crop and has been a focus of genetic, systematic and breeding research. The genetic and physiological bases of some important agronomic traits in cotton were investigated by QTL mapping through constructing of genetic map with chromosomal assignment. A segregating F2 population derived from an interspecific cross (G. barbadense x G. hirsutum) between two genotypes, cvs. "Giza 83" and "Deltapine" was used in this study. Different molecular markers including SSR, EST, EST-SSR, AFLP and RAPD were employed to identify markers that reveal differences between the parents. In total 42 new markers were merged with 140 previously mapped markers to produce a new map with 182 loci covering a total length of 2370.5 cM. Among these new markers, some of them were used to assign chromosomes to the produced 26 linkage groups. The LG2, LG3, LG11 and LG26 were assigned to chromosomes 1, 6, 5 and 20 respectively. Single point analysis was used to identify genomic regions controlling traits for plant height, number of nodes at flowering time, bolling date, days to flowering and number of bolls. In total 40 significant QTL were identified for the five traits on 11 linkage groups (1, 2, 3, 4, 5, 10, 11, 12, 18, 19 and 23). This work represents an improvement of the previously constructed genetic map in addition to chromosomal assignment and detection of new significant QTL for the five traits in Egyptian cotton. The Significant QTLs detected in this study can be employed in marker assisted selection for molecular breeding programs aiming at developing cotton cultivars with improved agronomic traits.

Identification of drought-inducible genes and differentially expressed sequence tags in barley

Drought limits cereal yields in several regions of the world and plant water status plays an important role in tolerance to drought. To investigate and understand the genetic and physiological basis of drought tolerance in barley, differentially expressed sequence tags (dESTs) and candidate genes for the drought response were mapped in a population of 167 F8 recombinant inbred lines derived from a cross between "Tadmor" (drought tolerant) and "Er/Apm" (adapted only to specific dry environments). One hundred sequenced probes from two cDNA libraries previously constructed from drought-stressed barley (Hordeum vulgare L., var. Tokak) plants and 12 candidate genes were surveyed for polymorphism, and 33 loci were added to a previously published map. Composite interval mapping was used to identify quantitative trait loci (QTL) associated with drought tolerance including leaf relative water content, leaf osmotic potential, osmotic potential at full turgor, water-soluble carbohydrate concentration, osmotic adjustment, and carbon isotope discrimination. A total of 68 QTLs with a limit of detection score > or =2.5 were detected for the traits evaluated under two water treatments and the two traits calculated from both treatments. The number of QTLs identified for each trait varied from one to 12, indicating that the genome contains multiple genes affecting different traits. Two candidate genes and ten differentially expressed sequences were associated with QTLs for drought tolerance traits.

Granulocyte-Macrophage Colony-Stimulating Factor in Newly Diagnosed Adult Patients with Acute Lymphoblastic Leukemia Treated with Conventional Chemotherapy

Twenty consecutive adult patients with newly diagnosed acute lymphoblastic leukemia (ALL) were treated with conventional therapy consisting of daunorubicin, vincristine, prednisone and L-asparaginase in standard doses. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered at a single subcutaneous daily dose of 5 microgram per kilogram body weight for fourteen days starting on day 7 of chemotherapy. Twenty two adult patients with acute lymphoblastic leukemia and similar risk characteristics who received the same chemotherapeutic regimen without GM-CSF served as a historical control group. The complete remission rate and the rate of early mortality were similar in both groups of patients. Patients treated with GM-CSF showed significantly faster neutrophil recovery above 0.5 × 10(9)/L than the control patients (P < 0.005). The incidence of febrile episodes and the rate of documented infection were similar in the two groups of patients.