Electrochemical Nano-biosensors as Novel Approach for the Detection of Lung Cancer-related MicroRNAs.

In both men and women around the world, lung cancer accounts as the principal cause of cancer-related death after breast cancer. Therefore, early detection of the disease is a cardinal step in improving prognosis and survival of patients. Today, the newly-defined microRNAs regulate about 30 to 60 percent of the gene expression. Changes in microRNA Profiles are linked to numerous health conditions, making them sophisticated biomarkers for timely, if not early, detection of cancer. Though evaluation of microRNAs in real samples has proved to be rather challenging, which is largely attributable to the unique characteristics of these molecules. Short length, sequence similarity, and low concentration stand among the factors that define microRNAs. Recently, diagnostic technologies with a focus on wide-scale point of care have recently garnered attention as great candidates for early diagnosis of cancer. Electrochemical nano-biosensors have recently garnered much attention as a molecular method, showing great potential in terms of sensitivity, specificity and reproducibility, and last but not least, adaptability to point-of-care testing. Application of nanoscale materials in electrochemical devices as promising as it is, brings multiplexing potential for conducting simultaneous evaluations on multiple cancer biomarkers. Thanks to their enthralling properties, these materials can be used to improve the efficiency of cancer diagnostics, offer more accurate predictions of prognosis, and monitor response to therapy in a more efficacious way. This article presents a concise overview of recent advances in the expeditiously evolving area of electrochemical biosensors for microRNA detection in lung cancer.

New insights into the roles and regulation of SphK2 as a therapeutic target in cancer chemoresistance.

Chemoresistance is a complicated process developed by most cancers and accounts for the majority of relapse and metastasis in cancer. The main mechanisms of chemoresistance phenotype include increased expression and/or activated drug efflux pumps, altered DNA repair, altered metabolism of therapeutics as well as impaired apoptotic signaling pathways. Aberrant sphingolipid signaling has also recently received considerable attention in chemoresistance. Sphingolipid metabolites regulate main biological processes such as apoptosis, cell survival, proliferation, and differentiation. Two sphingosine kinases, SphK1 and SphK2, convert sphingosine to sphingosine-1-phosphate, an antiapoptotic bioactive lipid mediator. Numerous evidence has revealed the involvement of activated SphK1 in tumorigenesis and resistance, however, contradictory results have been found for the role of SphK2 in these functions. In some studies, overexpression of SphK2 suppressed cell growth and induced apoptosis. In contrast, some others have shown cell proliferation and tumor promotion effect for SphK2. Our understanding of the role of SphK2 in cancer does not have a sufficient integrity. The main focus of this review will be on the re-evaluation of the role of SphK2 in cell death and chemoresistance in light of our new understanding of molecular targeted therapy. We will also highlight the connections between SphK2 and the DNA damage response. Finally, we will provide our insight into the regulatory mechanisms of SphKs by two main categories, micro and long, noncoding RNAs as the novel players of cancer chemoresistance.

Histone Deacetylase Inhibitor (Trapoxin A) Enhances Stemness Properties in Adipose Tissue Derived Mesenchymal Stem Cells.

BACK GROUND: Adipose tissue derived mesenchymal stem cells (ASCs) have unique potential for regenerative cell therapies. However, during ex-vivo cultivation, they undergo considerable quality loss regarding their phenotypic properties, stemness genes expression and differentiation potential. Recent studies reported that the loss of stemness properties of MSCs is a result of chromatin histone deacetylations through in-vitro cultivation. The present work aimed to study the effect of Trapoxin A (TPX) as a histone deacetylase inhibitor (HDACi) on overall stemness properties of ASCs. METHODS: First, the effects of TPX treatments on ASCs viability and proliferation were evaluated using MTT assay. Second, the desired doses of TPX supporting ASCs proliferation were determined and the lack of their negative effects was confirmed by DAPI staining. In addition, the influence of TPX on cell cycle of ASCs and the mRNA levels of stemness genes were measured by flowcytometry and qPCR, respectively. Finally, the effect of TPX treatment on osteogenic potential of ASCs was studied. RESULTS: The results indicated that short time TPX treatment (nM concentrations) caused stimulation of proliferation and considerable percentage of ASCs entered to S-phase of cell cycle (p<0.05). Moreover, the findings demonstrated significant up-regulation of stemness markers genes (Oct-4, Sox-2, Nanog, TERT, Klf-4, Rex-1) (p<0.05) and enhanced osteogenic differentiation potential of ASC after TPX treatment. CONCLUSION: The addition of low dose of TPX to the expansion medium could possibly enhance the stemness properties and prevent the quality decline of ex-vivo cultured ASCs.

Sphingosine kinase-2 Inhibitor ABC294640 Enhances Doxorubicin-Induced Apoptosis of NSCLC Cells via Altering Survivin Expression.

BACKGROUND: There is an urgent need to improve efficacy of chemotherapeutics to overcome resistance in cancer treatment. Sphingosine kinase-2 (SphK2) a key regulator of sphingolipid signaling has been rationalized as an important therapeutic target. We evaluated the role of SphK2 in doxorubicin (DOX)-induced apoptosis of NSCLC cells via altering c-FLIPS, MCL-1 and survivin expressions in order to overcome chemoresistance. METHODS: Proliferation and apoptosis were evaluated by MTT assay and DAPI staining, respectively. Cell population in each phase of cell cycle was determined by flow cytometric assay. Gene and protein expression levels were examined by quantitative RT-PCR and western blot analysis, respectively. RESULTS: Phorbol myristate acetate (PMA), a SphK2 stimulator, decreased cell death induced by IC50 of DOX (1.1 µM) to around 70% (p<0.01). Cell cycle analysis revealed a significant accumulation of the cells in S phase with a marked decrease in sub G1 phase when we incubated the cells with combined treatment of PMA and DOX (p<0.05). Adding ABC294640 (40 µM), a SphK2 inhibitor, significantly abolished PMA effect on cell survival (p<0.01). Survivin expression was significantly diminished by applying ABC294640 either alone or in DOX treated cells followed by increase in cell death (p<0.05), however, there was no significant change in MCL-1 expression by ABC294640 either alone or in DOX treated cells (p=0.16) and (p=0.06), respectively. CONCLUSION: Identifying cancer patients with high SphK2 expression and then inhibiting of SphK2 activity can be considered as an important strategy to increase the efficacy of DOX in the induction of apoptosis.