The current work aimed to synthesize selenium and zinc nanoparticles using the aqueous extract of Ephedra aphylla as a valuable medicinal plant. The prepared nanoparticles were characterized by TEM, zeta potential, and changes in the phytochemical constituents. Hence, the phenolic, flavonoid, and tannin contents were reduced in the case of the prepared samples of nanoparticles than the original values in the aqueous extract. The prepared extract of Ephedra aphylla and its selenium and zinc nanoparticles showed high potency as antioxidant agents as a result of the DPPH• assay. The samples were assessed as anticancer agents against six tumor cells and a normal lung fibroblast (WI-38) cell line. The selenium nanoparticles of Ephedra aphylla extract revealed very strong cytotoxicity against HePG-2 cells (inhibitory concentration (IC50) = 7.56 ± 0.6 µg/mL), HCT-116 cells (IC50 = 10.02 ± 0.9 µg/mL), and HeLa cells (IC50 = 9.23 ± 0.8 µg/mL). The samples were evaluated as antimicrobial agents against bacterial and fungal strains. Thus, selenium nanoparticles showed potent activities against Gram-negative strains (Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli), Gram-positive strains (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, and Staphylococcus epidermidis), and the fungal strain Candida albicans. In conclusion, the preparation of nanoparticles of either selenium or zinc is crucial for improved biological characteristics.
Approximately 90% of all cancer deaths arise from the metastatic spread of primary tumours. Of all the processes involved in carcinogenesis, local invasion and the formation of metastases are clinically the most relevant, but they are the least well understood at the molecular level. As a barrier to metastasis, cells normally undergo an apoptotic process known as 'anoikis', in circulation. The recent technological advances in the isolation and characterisation of rare circulating tumour cells (CTCs) will allow a better understanding of anoikis resistance. Detailed molecular and functional analyses of anoikis-resistant cells may provide insight into the biology of cancer metastasis and help identify novel targets for prevention of cancer dissemination. To uncover the molecular changes that govern the transition from a primary lung tumour to a secondary metastasis and specifically the mechanisms by which CTCs survive in circulation, we carried out whole genome sequencing (WGS) of normal lung, primary tumours and the corresponding brain metastases from five patients with progressive metastatic non-small-cell lung carcinoma. We also isolated CTCs from patients with metastatic cancer and subjected them to whole genome amplification and Sanger sequencing of genes of interest. While the primary tumours showed mutations in genes associated with cell adhesion and motility, brain metastases acquired mutations in adaptive, cytoprotective genes involved in response to cellular stress such as Keap-1, Nrf2 and P300, which are key players of the Keap1-Nrf2-ARE survival pathway. Nrf2 is a transcriptional factor that upon stress translocates into the nucleus, binds to the anti-oxidant response elements (ARE) and drives the expression of anti-oxidant genes. The identified mutations affect regulatory domains in all three proteins, suggesting a functional role in providing a survival advantage to CTCs in the peripheral blood allowing their dissemination to distant organs.
Glioblastoma (GBM) is the most aggressive brain tumor in adults and remains incurable despite multimodal intensive treatment regimens. The majority of GBM tumors show a mutated or overexpressed EGFR, however, tumors treated with tyrosine kinase inhibitors (TKIs) will inevitably recur highlighting the need to identify signalling pathways involved in GBM resistance to these drugs. To this end, we treated GBM cells that overexpress EGFR with increasing concentrations of gefitinib and isolated resistant clones. These resistant clones were subject to RNAseq and the expression of several genes was found to be upregulated. These genes are mainly tyrosine kinase receptors and include ROS1, DDR1 and PDGFRA and are known to control several downstream targets of EGFR. The upregulation of ROS1 and DDR1 was confirmed at the protein level by western blot. Treatment with a potent and highly specific pyrazole ROS1 inhibitor in ROS1 overexpressing clones led to a sensitization of these cells to low concentrations of gefitinib. Combined treatment with gefitinib and ROS1 inhibitor induces massive cell death by apoptosis following a prolonged S phase cell cycle arrest. Our current study led to the discovery of alternative pathways used by GBM cells to evade cell death following treatment with gefitinib and identifies new therapeutic targets to prevent GBM cell resistance to the drug.
Background: Autophagy is a catabolic process, utilized constitutionally by body cells to recycle nutrients and to remove unwanted/damaged intracellular constituents. It is enhanced during periods of stress, such as starvation and hypoxia, aiding in cell survival and it is linked to major cellular processes, such as apoptosis and antigen expression. The process has been extensively studied in vitro models or tumor tissue samples with rare application on human subjects. Methods: Plasma samples from 24 advanced solid tumor patients were collected at different time points before and after chemotherapy. Their exosomes were isolate and blotted for microtubule-associated protein-1 light chain-3 (LC-3B) protein as a marker for autophagy. All the subjects received a standard chemotherapy regimen of carboplatingemcitabine with chloroquine (CQ)/ hydroxychloroquine (HCQ) in chronic doses throughout their treatment period as an autophagy modulator. CQ/HCQ was given in 50 mg increments as guided by their tolerability to treatment. Results: A total of 267 plasma samples were obtained for the 24 patients and processed. Each sample corresponds to a single time point. The first group included 6 patients, all received 50 mg of CQ with chemotherapy. LC-3B I was detected in their isolated exosomes, while LC3-BII was not detected in their samples. The second cohort of patients included 3 subjects who re-ceived 100mg of HCQ. They demonstrated both LC3-BI and II on day 15 after chemotherapy in one patient, and on third cycle after 24 hours in the second patient. The third cohort included 3 subjects who received 150 mg of HCQ. All cases demonstrated LC3-BI and II on first cycle of treatment after less than 24 hours. The last cohort included 8 subjects, who received a fixed dose of 100 mg of HCQ with treatment. In this cohort, we were able to detect both LC3-B isoforms on advanced time points of second and third cycles. Conclusion: Detection of autophagy protein LC3-B in exosomes serves as a dynamic method to monitor autophagy. It can be utilized to study the effects of anti-neoplastic agents on autophagy and mechanisms of drug resistance, however, to standardize our results a larger specimen of patients should be included.
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