Neo vessel formation by angiogenesis is an important event during many pathological conditions including cancer, where it is indispensable for tumor growth and survival. Although, various pro-angiogenic cytokines and soluble factors, secreted by tumor cells, have been reported to promote angiogenesis, recent studies have shown regulatory role of exosomes, secreted by tumor cells in the process of angiogenesis. These exosomes are capable of carrying nucleic acids, proteins, etc., as their cargo. Under the light of these facts and considering the presence of miRNAs, the non-coding RNAs capable of regulating target gene expression, as one of the major cargos in the exosomes, we investigated, whether exosomes derived from normoxic and hypoxic tumor cell colonies exhibit difference in levels of miR-23∼27∼24 cluster members and if so, to check the significance of their horizontal transfer on the process of angiogenesis. Results of our study showed that exosomes secreted by hypoxic tumor cell colonies possess significantly higher levels of miR23a and can induce angiogenesis. Further, we have shown that exosomes secreted by cells that ectopically over express miR23a is capable of inducing angiogenesis in different angiogenic model systems such as CAM, in ovo Xenograft and HUVEC models systems. Further, mechanistic analysis revealed that miR23a driven regulation of angiogenesis is brought about by down regulation of SIRT1 in the recipient cells. Collectively, the results presented here suggest that exosomal transfer of miR23a from tumor cell colonies can induce the process of angiogenesis by targeting SIRT1 in the recipient endothelial cells.
A simple method was employed for the synthesis of green luminescent carbon quantum dots (CQDs) from styrene soot. The CQDs were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared, and Raman spectroscopy. The prepared carbon quantum dots did not show cellular toxicity and could successfully be used for labeling cells. We also evaluated the effects of carbon quantum dots on the process of angiogenesis. Results of a chorioallantoic membrane (CAM) assay revealed the significant decrease in the density of branched vessels after their treatment with CQDs. Further application of CQDs significantly downregulated the expression levels of pro-angiogenic growth factors like VEGF and FGF. Expression of VEGFR2 and levels of hemoglobin were also significantly lower in CAMs treated with CQDs, indicating that the CQDs inhibit angiogenesis. Data presented here also show that CQDs can selectively target cancer cells and therefore hold potential in the field of cancer therapy.
A carbon quantum
dot-based carbon paste electrode was fabricated
and used for the determination of adrenaline (AD) at the nanomolar
level. This fabricated electrode exhibited tremendous electrocatalytic
activity for the oxidation of adrenaline in supporting electrolyte
(PBS of pH 7.4). Scan rate variation studies with the modified electrode
revealed that the overall electrode process was controlled by a diffusion
process. A lower detection limit of 6 nM was achieved by chronoamperometry.
Interference by biological molecules such as serotonin (5-HT) and
ascorbic acid (AA) in the electrochemical oxidation of AD on the fabricated
electrode was tested. It was observed that with the modified electrode,
the selective determination of AD was possible. Further, with the
fabricated electrode, simultaneous analysis of AA, AD, and 5-HT was
performed, and it was observed that the overlapped peaks of these
analytes on the naked electrode were well resolved into three peaks
on the modified electrode. Along with decent sensitivity and selectivity,
the electrode also showed higher stability and antifouling nature.
The real-time application of the projected scheme was proven by employing
the said electrode for adrenaline in adrenaline bitartrate injections.
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