Cancer stem cell-like cells (CSCs) are cancer cells that have the ability of self-renewal and differentiation into multiple malignant cell types (hierarchy). Thus, can cause relapses and metastasis. CSCs’ phenotype is defined by special transcription factors such as Nanog, Oct3/4, Sox2, Nestin, and CD34. The present study aims to determine the change in gene expression of the above markers in correlation with the stage of the disease in breast cancer patients. Initially, whole blood samples from patients with breast cancer were collected, followed by the isolation and culture of circulating tumor cells (CTCs). This was followed by the quantification of CSCs from the above cultures. CSCs’ molecular analysis was performed with qPCR, with the use of gene specific primers. At the same time of the analysis, the clinical assessments of the patients were requested from their physicians. The results indicated a linear relationship between the gene expression of stemness markers and the stage of the disease, as well as specific expression patterns by stage. It seems that these genes have an important role in the progression of the disease, thus they might be target for new treatment approaches.
Conceptually, multi-functional enzymes are attractive because in the case of complex polymer hydrolysis having two or more activities defined by a single enzyme offers the possibility of synergy and reduced enzyme cocktail complexity. Nevertheless, multi-functional enzymes are quite rare and are generally multi-domain assemblies with each activity being defined by a separate protein module. However, a recent report described a GH51 arabinofuranosidase from Alicyclobacillus sp. A4 that displays both α-l-arabinofuranosidase and β-d-xylanase activities, which are defined by a single active site. Following on from this, we describe in detail another multi-functional GH51 arabinofuranosidase and discuss the molecular basis of multifunctionality. THSAbf is a GH51 α-l-arabinofuranosidase. Characterization revealed that THSAbf is active up to 75 °C, stable at 60 °C and active over a broad pH range (4–7). THSAbf preferentially releases para-nitrophenyl from the l-arabinofuranoside (k cat/K M = 1050 s−1 mM−1) and to some extent from d-galactofuranoside and d-xyloside. THSAbf is active on 4-O-methylglucuronoxylans from birch and beechwood (10.8 and 14.4 U mg−1, respectively) and on sugar beet branched and linear arabinans (1.1 ± 0.24 and 1.8 ± 0.1 U mg−1). Further investigation revealed that like the Alicyclobacillus sp. A4 α-l-arabinofuranosidase, THSAbf also displays endo-xylanase activity, cleaving β-1,4 bonds in heteroxylans. The optimum pH for THASAbf activity is substrate dependent, but ablation of the catalytic nucleophile caused a general loss of activity, indicating the involvement of a single active center. Combining the α-l-arabinofuranosidase with a GH11 endoxylanase did not procure synergy. The molecular modeling of THSAbf revealed a wide active site cleft and clues to explain multi-functionality. The discovery of single active site, multifunctional enzymes such as THSAbf opens up exciting avenues for enzyme engineering and the development of new biomass-degrading cocktails that could considerably reduce enzyme production costs.
Background: Platinum derivatives are used widely for the treatment of many cancers. However, the toxicity that is observed makes imperative the need for new drugs, or new combinations. Anvirzel™ is an extract which has been demonstrated with experimental data that displays anticancer activity. The aim of the present study is to determine whether the combination of Cisplatin and Anvirzel™ has a synergistic effect against different types of cancer. Materials and methods: To measure the efficacy of treatment with Cisplatin and Anvirzel™, methyl-tetrazolium dye (MTT) chemosensitivity assays were used incorporating established human cancer cell lines. Measurements were performed in triplicates, three times, using different incubation times and different concentrations of the two formulations in combination or on their own. t-test was used for statistical analysis. Results: In the majority of the cell lines tested, lower concentrations of Anvirzel™ induced a synergistic effect when combined with low concentrations of Cisplatin after an incubation period of 48 to 72 h. The combination of Anvirzel™/Cisplatin showed anti-proliferative effects against a wide range of tumours. Conclusion: The results showed that the combination of Anvirzel™ and Cisplatin is more effective than monotherapy, even when administered at low concentrations; thus, undesirable toxic effects can be avoided.
21 August 2013 in Journal of Receptors and Signal Transduction
Context: The Notch signaling pathway is one of the most important pathways during normal development and implicated in self-renewal of adult stem cells and differentiation of progenitor cells. Abnormal expression of Notch receptors has been associated with many epithelial metaplastic and neoplastic lesions. Objective-materials and methods: In this particular study, it was determined the relative gene expression of Notch receptors after knockdown experiments in colon cancer stem cells (CSCs) and the gene expression changes in stemness transcription factors (Oct4, Sox2, Nanog), as well in dipeptidylpeptidase-4, CD44 antigen, Met proto-oncogene and in Metnase transposase. Results: In control CSCs Notch-2 had the higher expression, followed by Notch-1, Notch-3. Notch-4 demonstrated the lower gene expression among the receptors. The suppression of Notch-1 led to increased expression of Oct4 and Sox2, but in decreased gene expression of cMET, Setmar and CD44. The CD26 expression remained unchanged. The knockdown of Notch-2 led to decreased expression of all transcription factors. Notch-3 down regulation caused increased Oct4 gene expression, but decreased levels for the rest of the genes. Finally, the suppression of Notch-4 had the same effect as in receptor Notch-3. Discussion and conclusion: The above experimental data suggest the possible interaction between the four different receptors of Notch signaling pathway. The expression of CD26, cMET and N-methyltransferase Setmar was also changed. Finally, the stemness phenotype was changed in a different way each time, according to the receptor that was down regulated. All Notch receptors and particularly Notch-2 seem to play an important role in cancer stem cells.
11 December 2013 in Journal of Signal Transduction
The AP-1 transcription factor is a heterodimer protein that regulates gene expression in response to a variety of extrinsic stimuli through signal transduction. It is involved in processes including differentiation, proliferation, and apoptosis. Among the genes it regulates are transcription factors that contribute to the stemness phenotype. Cancer stem cells have the ability to self-renew and initiate differentiation into heterogenic cancer cells, which may cause metastasis and relapses. In the present study, we evaluated the effect of AP-1 complexes, as well as the C-FOS and C-JUN genes, in relation to NANOG, OCT3/4, and SOX2 transcription factors. All assays were undertaken with colon cancer stem cells. Knockdown experiments with siRNA were performed for each individual gene as well as their combination. Changes in gene expression were calculated with quantitative polymerase chain reaction experiments, while the effect on cell cycle distribution and apoptosis was studied by flow cytometry. The results differed depending on the percentage of repression, as well as the gene that was suppressed. In all cases, the number of apoptotic cells was increased. These findings indicate that AP-1 may have a crucial role in the maintenance of cancer stem cells.