In cancer progression, proteolytic enzymes like serine proteases and metalloproteinases degrade the basement membrane enabling the tumor cells to invade the adjacent tissues. Thus, invasion and metastasis are augmented by these enzymes. Simultaneous silencing of uPA and MMP9 in breast cancer cells decreased the wound healing, migratory, invasive and adhesive capacity of the cells. After simultaneous down regulation, cells were seen to be arrested in the cell cycle. There was a remarkable increase in the expression of cell to cell adhesion molecule E–cadherin, and decrease in Vimentin and Snail expression. In addition, there was a significant decrease in the expression of the stem cell marker Oct-4. In the breast tumor samples it has been observed that, tumors, expressing higher level of uPA and MMP9, express less amount of E–cadherin. It has also been observed that few tumors also show, Vimentin positive in the ductal epithelial area. Thus, our model can help for checking the aggressive tumor invasion by blocking of uPA and MMP9. Our present observations also give the concept of the presence of aggressive epithelial cells with mesenchymal nature in the tumor micro-environment, altering the expression of EMT genes.

A novel Schiff base receptor (L) bearing catechol and phenol groups was synthesized and characterized by various spectral (FTIR, ¹H NMR and mass) data. The anion recognition ability of L was investigated by experimental (UV-Vis, fluorescence and ¹H NMR) and theoretical (B3LYP/6-31G**) methods. Among the tested anions, the receptor L showed both naked-eye detectable color change from light-yellow to intense brownish-yellow and spectral (hyperchromic shift at 450 nm and ‘turn-on’ fluorescence at 480 nm) changes selectively towards F⁻ and AcO⁻ in DMSO and mixed DMSO–H₂O medium because of the formation of a hydrogen bonded anion-receptor complex followed by the deprotonation of L. The receptor L was tested for live breast cancer cell imaging and can be applied to the breast tumour diagnosis.

A new phthalazine based chemosensor 3 was developed for the highly selective and sensitive detection of Co²⁺ in the mixed solvent system, CH₃CN–H₂O (1 : 1, v/v). In the presence of Co²⁺, the colour of the solution 3 changed from yellow to green; the absorption maxima of 3 was red-shifted from 383 nm to 435 nm, and the fluorescence of 3 at 550 nm was significantly enhanced. The sensor 3 showed a detection limit down to 25 nM by forming a complex species with Co²⁺ in 1 : 1 stoichiometry. Furthermore, by means of confocal laser scanning microscopy experiments, it has demonstrated that it can be used as a fluorescent probe for monitoring Co²⁺ in living cells.

A new anion selective chemosensor L was derived through a direct condensation reaction between pyridoxal and thiosemicarbazide. Sensor L showed selective recognition and sensing ability towards F⁻ and AcO⁻ anions through a naked-eye detectable color change from colorless to light yellow, appearance of a new charge transfer absorption band at 404 nm and significant “turn-on” fluorescence at 506 nm. The detection limit of L as a fluorescent ‘turn-on’ sensor for the analysis of F⁻ and AcO⁻ was estimated to be 0.10 μM. The anion sensing mechanisms of L was supported by ¹H NMR and DFT results. Finally, the cytotoxicity effect of L and its ability to image intracellular F⁻ ions in the living HeLa cells was investigated.