Bioinspired silk fibroin nano-delivery systems protect against 5-FU induced gastrointestinal mucositis in a mouse model and display antitumor effects on HT-29 colorectal cancer cells in vitro.

Colorectal cancer (CRC), is the second cause of cancer-related deaths worldwide is one of the most prevalent types of cancers. Conventional treatment continues to rely on surgery, chemotherapy, and radiotherapy, but for advanced cases, adjuvant chemotherapy remains the main approach for improving surgical outcomes and lower the disease recurrence probability. Chemotherapy-induced gastrointestinal (GI) toxicity is the main dose-limiting factor for many chemotherapeutic regimens, including 5-FU, and one of the biggest oncological challenges. Up to 40% of the patients receiving 5-FU get mucositis, 10-15% of which develop severe symptoms. In this context, our study aimed to develop a bioinspired nanosized drug delivery system as a strategy to reduce 5-FU associated side effects, such as GI mucositis. To this end, SF-based nanoparticles were prepared and characterized in terms of size and morphology, as well as in terms of in vitro antitumoral activity on a biomimetic colorectal cancer model by investigation of apoptosis, DNA fragmentation, and release of reactive oxygen species. Additionally, the capacity of the SF-based nanocarriers to offer intestinal protection against 5-FU-induced GI mucositis was evaluated in vivo using a mouse model that mimics the chemotherapy-associated gut mucositis occurring in colorectal cancer. Our studies show that silk fibroin nanoparticles efficiently deliver 5-FU to tumor cells in vitro while protecting against drug-induced GI mucositis in a mouse model.

In vitro blood compatibility and in vitro cytotoxicity of amphiphilic poly-N-vinylpyrrolidone nanoparticles.

This study focused on defining the in vitro behavior of amphiphilic poly-N-vinylpyrrolidone (Amph-PVP) nanoparticles toward whole blood, blood plasma and blood cells in order to assess nanoparticle blood compatibility. In addition, possible effects on endothelium cell growth/viability were evaluated. The Amph-PVP nanoparticles were formed via self-assembling in aqueous media and composed of a hydrophobic alkyl core and a hydrophilic PVP outer shell. Their blood compatibility was evaluated by investigating their effect on red blood cells (RBCs) or erythrocytes, white blood cells (WBCs) or leukocytes, platelets (PLTs) and on complement system activation. Our results clearly demonstrate that the Amph-PVP nanoparticles are stable in presence of blood serum, have no significant effects on the function of RBCs, WBCs, PLTs and complement system activation. The Amph-PVP nanoparticles did not show considerable hemolytic or inflammatory effect, neither influence on platelet aggregation, coagulation process, or complement activation at the tested concentration range of 0.05-0.5 mg/ml. The Amph-PVP nanoparticles did not exhibit any significant effect on HMEC-1 microvascular skin endothelial cells' growth in in vitro experiments. The excellent blood compatibility of the Amph-PVP nanoparticles and the lack of effect on endothelium cell growth/viability represent a crucial feature dictating their further study as novel drug delivery systems.

Stereospecificity of hydrogen transfer by the NAD(+)-linked alcohol dehydrogenase from the Antarctic psychrophile Moraxella sp. TAE123.

Investigation of the stereochemistry of the hydride transfer in reactions catalyzed by the recently isolated NAD(+)-linked alcohol dehydrogenase from the Antarctic psychrophile Moraxella sp. TAE123 was accomplished by using 1H NMR spectroscopy of the deuterated coenzyme. It was found that this new psychrophilic enzyme is a type A dehydrogenase. Moraxella sp. ADH reduces stereospecifically 2-butanone to produce (S)-2-butanol.

Purification and characterization of an alcohol dehydrogenase from the Antarctic psychrophile Moraxella sp. TAE123.

An NAD+-dependent alcohol dehydrogenase (ADH) of the Antarctic psychrophile Moraxella sp. TAE123 was purified to homogeneity with an overall yield of 16.7% and further characterized. The native enzyme had an apparent molecular mass of 240 kDa and consisted of four identical 52-kDa subunits. The pI of the enzyme was determined to be 5.5, while its optimum pH is 7.5. The enzyme contained 1 zinc atom/subunit and exhibited a remarkable thermal lability. Moraxella sp. TAE123 ADH exhibited a wide range of substrate specificity similar to its mammalian counterparts and in contrast to other microbial ADHs. It oxidized mainly primary and secondary aliphatic alcohols. The highest reaction rate was observed when ethanol was used as substrate. A gradual decrease in rate was observed by increasing the length and branching of the carbon chain of the alcohol. This enzyme oxidized effectively large bulky alcohols, such as diphenylmethanol. Reduction of aldehydes and ketones was also observed. N-terminal amino acid sequence analysis of the enzyme did not reveal any similarity with the amino termini of all other ADHs, while an unexpected significant similarity was observed with the amino terminal sequence of four prokaryotic aldehyde dehydrogenases.