Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/ iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/ macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/ iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer.
Numerous proteases are known to be necessary for cancer development and progression including matrix metalloproteinases (MMPs), tissue serine proteases, and cathepsins. The goal of this research is to develop an Fe/Fe3O4 nanoparticle-based system for clinical diagnostics, which has the potential to measure the activity of cancer-associated proteases in biospecimens. Nanoparticle-based "light switches" for measuring protease activity consist of fluorescent cyanine dyes and porphyrins that are attached to Fe/Fe3O4 nanoparticles via consensus sequences. These consensus sequences can be cleaved in the presence of the correct protease, thus releasing a fluorescent dye from the Fe/Fe3O4 nanoparticle, resulting in highly sensitive (down to 1 × 10(-16) mol l(-1) for 12 proteases), selective, and fast nanoplatforms (required time: 60 min).
The study aimed to determine the antibacterial/antibiofilm effect and mechanism of interaction of curcuminoids-intercalated Mg/Al layered double hydroxide (curcuminoids-LDH) against three different bacteria. Antimicrobial effect of curcuminoids-LDH nanohybrid was investigated against P. aeruginosa, S. aureus, and E. faecalis (for both standard strains and clinical isolates), using agar well diffusion method. Minimum inhibitory concentrations (MIC) of planktonic bacteria were determined using the broth microdilution method. MIC of biofilms (MBIC ) and killing time for 48 hr matured biofilms were determined by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Scanning electron microscopy (SEM) was used to determine pre- and postexposure architecture of biofilms. The mechanism of the antibiofilm activity of curcuminoids-LDH was determined using UV-visible spectroscopy. All tested bacteria had given a zone of inhibition in the presence of curcuminoids-LDH. The MIC values were 0.200 g/ml for P. aeruginosa, 0.025 g/ml for S. aureus, and 0.100 g/ml for E. faecalis. The 48 hr matured biofilms were reduced by curcuminoids-LDH with an MBIC of 0.100 g/ml. The minimum time to achieve MBIC was 3 hr, and the reduction was constant until 48 hr. SEM images showed a significant reduction of biofilm cell density and exopolymer matrics for all biofilms in the presence of curcuminoids-LDH. UV-visible studies revealed the antibiofilm activity of curcuminoids-LDH as due to the auto-oxidation of curcuminoids. The oxidation products are more limited in both product concentration per unit time and the variety of products, compared to pure curcuminoids, resulting in sharper UV-visible peaks than in the case of the latter. Curcuminoids-LDH has a potential antibacterial activity against P. aeruginosa, S. aureus, and E. faecalis. An antibiofilm activity has been achieved within 3 hr of the treatment. Curcuminoids released from the LDH showed the antibacterial activity due to oxidation products interfering with bacterial cell functions, and also encapsulation in the LDH causes curcuminoids to exhibit the activity in a persistent manner compared to pure curcuminoids.
SummaryProteases, including matrix metalloproteinases (MMPs), tissue serine proteases, and cathepsins (CTS) exhibit numerous functions in tumor biology. Solid tumors are characterized by changes in protease expression levels by tumor and surrounding tissue. Therefore, monitoring protease levels in tissue samples and liquid biopsies is a vital strategy for early cancer detection. Water-dispersable Fe/Fe3O4-core/shell based nanoplatforms for protease detection are capable of detecting protease activity down to sub-femtomolar limits of detection. They feature one dye (tetrakis(carboxyphenyl)porphyrin (TCPP)) that is tethered to the central nanoparticle by means of a protease-cleavable consensus sequence and a second dye (Cy 5.5) that is directly linked. Based on the protease activities of urokinase plasminogen activator (uPA), MMPs 1, 2, 3, 7, 9, and 13, as well as CTS B and L, human breast cancer can be detected at stage I by means of a simple serum test. By monitoring CTS B and L stage 0 detection may be achieved. This initial study, comprised of 46 breast cancer patients and 20 apparently healthy human subjects, demonstrates the feasibility of protease-activity-based liquid biopsies for early cancer diagnosis.
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