Aspergillus Niger thermostable Cytosine deaminase-dextran conjugates with enhanced structure stability, proteolytic resistance, and Antiproliferative activity.

Cytosine deaminase (CDA) is a prodrug mediating enzyme converting 5-flurocytosine into 5-flurouracil with profound broad-range anticancer activity towards various cell lines. Availability, molecular stability, and catalytic efficiency are the main limiting factors halting the clinical applications of this enzyme on prodrug and gene therapies, thus, screening for CDA with unique biochemical and catalytic properties was the objective. Thermotolerant/ thermophilic fungi could be a distinctive repertoire for enzymes with affordable stability and catalytic efficiency. Among the recovered thermotolerant isolates, Aspergillus niger with optimal growth at 45 °C had the highest CDA productivity. The enzyme was purified, with purification 15.4 folds, molecular mass 48 kDa and 98 kDa, under denaturing and native PAGE, respectively. The purified CDA was covalently conjugated with dextran with the highest immobilization yield of 75%. The free and CDA-dextran conjugates have the same optimum pH 7.4, reaction temperature 37 °C, and pI 4.5, and similar response to the inhibitors and amino acids suicide analogues, ensuring the lack of effect of dextran conjugation on the CDA conformational structure. CDA-Dextran conjugates had more resistance to proteolysis in response to proteinase K and trypsin by 2.9 and 1.5 folds, respectively. CDA-Dextran conjugates displayed a dramatic structural and thermal stability than the free enzyme, authenticating the acquired structural and catalytic stability upon dextran conjugation. The thermal stability of CDA was increased by about 1.5 folds, upon dextran conjugation, as revealed from the half-life time (T1/2). The affinity of CDA-conjugates (Km 0.15 mM) and free CDA (Km 0.22 mM) to deaminate 5-fluorocytosine was increased by 1.5 folds. Upon dextran conjugation, the antiproliferative activity of the CDA towards the different cell lines "MDA-MB, HepG-2, and PC-3" was significantly increased by mediating the prodrug 5-FC. The CDA-dextran conjugates strongly reduce the tumor size and weight of the Ehrlich cells (EAC), dramatically increase the titers of Caspase-independent apoptotic markers PARP-1 and AIF, with no cellular cytotoxic activity, as revealed from the hematological and biochemical parameters.

Barhi date (Phoenix dactylifera) extract ameliorates hepatocellular carcinoma in male rats.

Hepatocellular carcinoma (HCC) is a malignant tumor with limited treatment options. Given this fact, it may be important to develop new molecular targeted therapies from natural products, especially those which are primary sources of effective anticancer drugs with distinct mechanisms. Moreover, the complementary use of traditional herbs or fruit may increase the possibility of finding curative options for cancer. Here we explore the anticancer effects and possible molecular mechanism of Barhi date extract using an HCC rat model. Thirty two male albino rats were arbitrarily allocated into four groups: a negative control group (NCG); a positive control group (PCG), which received CCl4 (1 ml/kg b.wt./ i.p.) twice a week for three months; a Barhi date extract (400 mg/kg b.wt./day/orally) treatment group (DTG) during the third month of CCl4 administration; and a cisplatin (1.5 mg/kg b.wt./ i.p.) treatment group ( CTG) during the third month of CCl4 administration. After treatment we performed biochemical analyses of all groups to assess relative eukaryotic initiation factor 2 alpha (eIF2α), extracellular signal-regulated kinases (ERKs), protein kinase RNA-like endoplasmic reticulum kinase (PERK), poly (ADP-ribose) polymerase (PARP), and CASPASE 3 protein content, and examined expression of the genes phosphatase and tensin homolog (PTEN) and protein kinase B (AKT). We also performed an immunohistochemistry assay for alpha-fetoprotein (AFP). Our data showed higher PARP and CASPASE3 levels and liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and alkaline phosphatase [ALP]) in the PCG compared to the DTG and the cisplatin treatment group CTG. However, we also found a significant decrease in PTEN in the PCG relative to both the DTG and the CTG. We conclude that the anti-tumor activity of Barhi date extract may be mediated by the inhibition of cell proliferation and apoptosis via the ERK /PARP/caspase3 pathway and the AKT/ PTEN signaling pathways.

Exploiting the Biosynthetic Potency of Taxol from Fungal Endophytes of Conifers Plants; Genome Mining and Metabolic Manipulation.

Endophytic fungi have been considered as a repertoire for bioactive secondary metabolites with potential application in medicine, agriculture and food industry. The biosynthetic pathways by fungal endophytes raise the argument of acquisition of these machineries of such complex metabolites from the plant host. Diterpenoids "Taxol" is the most effective anticancer drug with highest annual sale, since its discovery in 1970 from the Pacific yew tree, Taxus brevifolia. However, the lower yield of Taxol from this natural source (bark of T. brevifolia), availability and vulnerability of this plant to unpredicted fluctuation with the ecological and environmental conditions are the challenges. Endophytic fungi from Taxus spp. opened a new avenue for industrial Taxol production due to their fast growth, cost effectiveness, independence on climatic changes, feasibility of genetic manipulation. However, the anticipation of endophytic fungi for industrial Taxol production has been challenged by the loss of its productivity, due to the metabolic reprograming of cells, downregulating the expression of its encoding genes with subculturing and storage. Thus, the objectives of this review were to (1) Nominate the endophytic fungal isolates with the Taxol producing potency from Taxaceae and Podocarpaceae; (2) Emphasize the different approaches such as molecular manipulation, cultural optimization, co-cultivation for enhancing the Taxol productivities; (3) Accentuate the genome mining of the rate-limiting enzymes for rapid screening the Taxol biosynthetic machinery; (4) Triggering the silenced rate-limiting genes and transcriptional factors to activates the biosynthetic gene cluster of Taxol.

Conjugation of Aspergillus flavipes Taxol with Porphyrin Increases the Anticancer Activity of Taxol and Ameliorates Its Cytotoxic Effects.

Taxol is one of the potential anticancer drugs; however, the yield of Taxol and its cytotoxicity are common challenges. Thus, manipulating the Taxol biosynthetic pathway from endophytic fungi, in addition to chemical modification with biocompatible polymers, is the challenge. Four fungal isolates, namely, Aspergillus flavipes, A. terreus, A. flavus, and A. parasiticus, were selected from our previous study as potential Taxol producers, and their potency for Taxol production was evaluated in response to fluconazole and silver nitrate. A higher Taxol yield was reported in the cultures of A. flavipes (185 µg/L) and A. terreus (66 µg/L). With addition of fluconazole, the yield of Taxol was increased 1.8 and 1.2-fold for A. flavipes and A. terreus, respectively, confirming the inhibition of sterol biosynthesis and redirecting the geranyl phosphate pool to terpenoids synthesis. A significant inhibition of ergosterol biosynthesis by A. flavipes with addition of fluconazole was observed, correlating with the increase on Taxol yield. To increase the Taxol solubility and to reduce its cytotoxicity, Taxol was modified via chemical conjugation with porphyrin, and the degree of conjugation was checked from the Thin layer chromatography and UV spectral analysis. The antiproliferative activity of native and modified Taxol conjugates was evaluated; upon porphyrin conjugation, the activity of Taxol towards HepG2 was increased 1.5-fold, while its cytotoxicity to VERO cells was reduced 3-fold.

Policosanol as a new inhibitor candidate for vascular calcification in diabetic hyperlipidemic rats.

This work mainly aimed to investigate the probable changes of aortic calcification by policosanol, omega-3 fatty acids in comparison with atorvastatin and subsequent progression of atherosclerosis in diabetic hyperlipemic rat model. Adult male albino rats of wistar strain (30) were divided into five groups (n = 6/group); one was fed normal diet and was used as a normal group, the other groups received alloxan, atherogenic diet (CCT - rat chow diet supplemented with 4% cholesterol, 1% cholic acid, and 0.5% thiouracil) and categorized as follows: the second group received no treatment and kept as control (diabetic hyperlipidemic control group (DHC)). The other groups received daily oral doses of atorvastatin, policosanol (10 mg/kg body weight) and ω-3 (50 mg/kg body weight), respectively, for eight weeks. Different biomarkers were used for the evaluation that included inflammatory (C reactive protein (CRP), tumor necrosis factor α (TNF-α)), oxidative stress (glutathione (GSH), malondialdehyde (MDA)) bone calcification markers (alkaline phosphatase (ALP), Vitamin D, parathyroid hormone (PTH)), lipogram pattern in addition to histochemical demonstration of calcium in the aorta. Diabetic hyperlipemic group demonstrated significant hyperglycemia, hyperlipidemia, and increased inflammation, oxidative stress, calcification, and finally atherogenesis progression. Treatment of diabetic hyperlipemic rats with, policosanol, omega-3 fatty acids (natural products) and atorvastatin for eight weeks significantly increased high-density lipoprotein cholesterol (HDL-C), Vitamin D, decreased aortic vacuoles number, and inhibited calcification process. Policosanol induced more remarkable reduction in the density and number of foam cells and improved the intimal lesions of the aorta as compared to atorvastatin. Drugs under study exerted hypoglycemic effect along with an inhibition of inflammation, oxidative stress, and calcium deposition with certain variations but policosanol effect was remarkable in comparison with other drugs.