Biomedical Promise of Sustainable Microwave-Engineered Symmetric Curcumin Derivatives.

Curcumin is a polyphenol of the Curcuma longa plant, which can be used for various medicinal purposes, such as inflammation and cancer treatment. In this context, two symmetric curcumin derivatives (D1-(1E,6E)-1,7-bis(4-acetamidophenyl)hepta-1,6-diene-3,5-dione and D2-p,p-dihydroxy di-cinnamoyl methane) were obtained by the microwave-based method and evaluated for their antitumoral effect on human cervix cancer in comparison with toxicity on non-tumoral cells, taking into account that they were predicted to act as apoptosis agonists or anti-inflammatory agents. The HeLa cell line was incubated for 24 and 72 h with a concentration of 50 µg/mL of derivatives that killed almost half of the cells compared to the control. In contrast, these compounds did not alter the viability of MRC-5 non-tumoral lung fibroblasts until 72 h of incubation. The nitric oxide level released by HeLa cells was higher compared to MRC-5 fibroblasts after the incubation with 100 µg/mL. Both derivatives induced the decrease of catalase activity and glutathione levels in cancer cells without targeting the same effect in non-tumoral cells. Furthermore, the Western blot showed an increased protein expression of HSP70 and a decreased expression of HSP60 and MCM2 in cells incubated with D2 compared to control cells. We noticed differences regarding the intensity of cell death between the tested derivatives, suggesting that the modified structure after synthesis can modulate their function, the most prominent effect being observed for sample D2. In conclusion, the outcomes of our in vitro study revealed that these microwave-engineered curcumin derivatives targeted tumor cells, much more specifically, inducing their death.

N-glycosylation state of TRPM8 protein revealed by terahertz spectroscopy and molecular modelling.

TRPM8 member of the TRP superfamily of membrane proteins participates to various cellular processes ranging from Ca2+ uptake and cold sensation to cellular proliferation and migration. TRPM8 is a large tetrameric protein with more than 70% of its residues located in the cytoplasm. TRPM8 is N-glycosylated, with a single site per subunit. This work focuses on the N-glycosylation of TRPM8 channel that was previously studied by our group in relation to proliferation and migration of tumoral cells. Here, experimental data performed with deglycosylating agents assess that the sole glycosylation site contains complex glycans with a molecular weight of 2.5 kDa. The glycosylation state of TRPM8 in cells untreated and treated with a deglycosylating agent was addressed with Terahertz (THz) spectroscopy. Results show a clear difference between cells comprising glycosylated and deglycosylated TRPM8, the first presenting an increased THz absorption. Human TRPM8 was modelled using as templates the available TRPM8 and other TRPM channels structures. Glycosylations were modelled by considering two glycan structures with molecular weight close to the experiment: shorter and branched at the first sugar unit (glc1) and longer and unbranched (glc2). Simulation of THz spectra based on the molecular dynamics of unglycosylated and the two glycosylated TRPM8 models in lipid membrane and solvation box showed that glycan structure strongly influences the THz spectrum of the channel and of other components from the simulation system. Only spectra of TRPM8 with glc1 glycans were in agreement with the experiment, leading to the validation of glc1 glycan structure.

N-glycosylation of the transient receptor potential melastatin 8 channel is altered in pancreatic cancer cells.

Transient receptor potential melastatin 8 (TRPM8), a membrane ion channel, is activated by thermal and chemical stimuli. In pancreatic ductal adenocarcinoma, TRPM8 is required for cell migration, proliferation, and senescence and is associated with tumor size and pancreatic ductal adenocarcinoma stages. Although the underlying mechanisms of these processes have yet to be described, this cation-permeable channel has been proposed as an oncological target. In this study, the glycosylation status of the TRPM8 channel was shown to affect cell proliferation, cell migration, and calcium uptake. TRPM8 expressed in the membrane of the Panc-1 pancreatic tumoral cell line is non-glycosylated, whereas human embryonic kidney cells transfected with human TRPM8 overexpress a glycosylated protein. Moreover, our data suggest that Ca2+ uptake is modulated by the glycosylation status of the protein, thus affecting cell proliferation.

Effects of Cd2+ on the epithelial Na+ channel (ENaC) investigated by experimental and modeling studies.

The function of the epithelial Na+ channel from the apical membrane of many Na+ transporting epithelia is modulated by various chemical compounds from the extracellular space, such as heavy metals, protons or chloride ions. We have studied the effect of extracellular Cd2+ on the function of the epithelial Na+ channel (ENaC) in heterologously expressed Xenopus laevis oocytes and Na+-transporting epithelia. We assayed channel function as the amiloride-sensitive sodium current (I(Na)). Cd2+ rapidly and voltage-independently inhibited INa in oocytes expressing αßγ Xenopus ENaC (xENaC). The extracellular Cd2+ inhibited Na+ transport and showed no influence on ENaC trafficking, as revealed by concomitant measurements of the transepithelial current, conductance and capacitance in Na+-transporting epithelia. Instead, amiloride inhibition was noticeably diminished in the presence of Cd2+ on the apical membrane. Using molecular modeling approaches, we describe the amiloride binding sites in rat and xENaC structures, and we present four putative binding sites for Cd2+. These results indicate that ENaC functions as a sensor for external Cd2+.