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Most of the existing scaffolds for guiding tissue regeneration do not provide direct mechanical stimulation to the cells grown on them. In this work, we used nanofibrous superparamagnetic scaffolds with applied magnetic fields to build a "dynamic" scaffold platform and investigated the modulating effects of this platform on the phenotypes of fibroblasts. The results of enzyme-linked immunosorbent and transwell assays indicated that fibroblasts cultivated in this platform secreted significantly higher type I collagen, vascular endothelial growth factor A, and transforming growth factor-β1 and did so in a time-dependent manner. At the same time, they produced fewer pro-inflammatory cytokines, including interleukin-1β and monocyte chemoattractant protein-1; this, in turn, accelerated the osteogenesis of preosteoblasts with the help of increased basic fibroblast growth factor as well as balanced extracellular matrix components. Mechanistic studies revealed that the platform modulated the phenotypic polarization of fibroblasts through the activation of components of integrin, focal adhesion kinase, and extracellular signal-regulated kinase signaling pathways and the inhibition of the activation of Toll-like receptor-4 and nuclear factor κB. Overall, the platform promoted the wound-healing phenotype of fibroblasts, which would be of great benefit to the scaffold-guided tissue regeneration.

Background Effects of different nanoparticles (NPs) exposure at acutely non-cytotoxic concentrations are particularly worthy to figure out, compare, and elucidate. Objective To investigate and compare the effect of a small library of NPs at non-cytotoxic concentration on the adherens junction of human umbilical vein endothelial cells (HUVECs), obtaining new insights of NPs safety evaluation. Materials and methods The HUVECs layer was exposed to NPs including gold (Au), platinum (Pt), silica (SiO 2 ), titanium dioxide (TiO 2 ), ferric oxide (Fe 2 O 3 ), oxidized multi-walled carbon nanotubes, with different surface chemistry and size distribution. Cellular uptake of NPs was observed by transmission electron microscopy. and the cytotoxicity was determined by Cell Counting Kit-8 assay. The NP-induced variation of intracellular reactive oxygen species (ROS) and catalase (CAT) activity was measured using the probe of 2ʹ7’-dichlorodihydr fluorescein diacetate and a CAT analysis kit, respectively. The level of VE-cadherin of HUVECs was analyzed by Western blot, and the loss of adherens junction was observed with laser confocal microscopy. Results The acutely non-cytotoxic concentrations of different NPs were determined and applied to HUVECs. The NPs increased the level of intracellular ROS and the activity of CAT to different degrees, depending on the characteristics. At the same time, the HUVECs lost their adherens junction protein VE-cadherin and gaps were formed between the cells. The NP-induced oxidative stress and gap formation could be rescued by the supplementary N-acetylcysteine in the incubation. Conclusion The increase of intracellular ROS and CAT activity was one common effect of NPs, even at the non-cytotoxic concentration, and the degree was dependent on the composition, surface chemistry, and size distribution of the NP. The effect led to the gap formation between the cells, while could be rescued by the antioxidant. Therefore, the variation of adherens junction between endothelial cells was suggested to evaluate for NPs when used as therapeutics and diagnostics.

Synthetic lethality is a powerful approach for targeting oncogenic drivers in cancer. Recent studies revealed that cancer cells with microsatellite instability (MSI) require Werner (WRN) helicase for survival; however, the underlying mechanism remains unclear. In this study, we found that WRN depletion strongly induced p53 and its downstream apoptotic target PUMA in MSI colorectal cancer (CRC) cells. p53 or PUMA deletion abolished apoptosis induced by WRN depletion in MSI CRC cells. Importantly, correction of MSI abrogated the activation of p53/PUMA and cell killing, while induction of MSI led to sensitivity in isogenic CRC cells. Rare p53-mutant MSI CRC cells are resistant to WRN depletion due to lack of PUMA induction, which could be restored by wildtype (WT) p53 knock in or reconstitution. WRN depletion or treatment with the RecQ helicase inhibitor ML216 suppressed in vitro and in vivo growth of MSI CRCs in a p53/PUMA-dependent manner. ML216 treatment was efficacious in MSI CRC patient-derived xenografts. Interestingly, p53 gene remains WT in the majority of MSI CRCs. These results indicate a critical role of p53/PUMA-mediated apoptosis in the vulnerability of MSI CRCs to WRN loss, and support WRN as a promising therapeutic target in p53 -WT MSI CRCs.

Arsenic sulfide (As 4 S 4 ) is a mineral drug that can be administrated orally and has been applied in the treatment of myeloid leukemia. The aim of this work is to investigate the therapeutic effect of As 4 S 4 in highly metastatic triple-negative breast cancer (TNBC) animal model, as As 4 S 4 has not been applied in the treatment of breast cancer yet. To overcome the poor solubility of original As 4 S 4 , a formulation of hydrophilic As 4 S 4 nanoparticles (e-As 4 S 4 ) developed previously was applied to mouse breast cancer cells as well as the tumor-bearing mice. It was shown that e-As 4 S 4 was much more cytotoxic than r-As 4 S 4 , strongly inhibiting the proliferation of the cells and scavenging intracellular reactive oxygen species (ROS). The oral administration of e-As 4 S 4 significantly increased the accumulation of arsenic in the tumor tissue and eliminated ROS in tumor tissues. Besides, e-As 4 S 4 could also inhibit the activation of hypoxia-inducible factor-1α (HIF-1α) and NLRP3 inflammasomes. Consequently, the angiogenesis was reduced, the metastasis to lung and liver was inhibited and the survival of tumor-bearing mice was prolonged. In conclusion, e-As 4 S 4 holds great potential for an alternative therapeutics in the treatment of breast cancer, due to its unique function of correcting the aggressive microenvironment.

Background Chronic myeloid leukemia (CML) is a myeloproliferative disorder due to the existence of BCR-ABL fusion protein that allows the cells to keep proliferating uncontrollably. Although tyrosine kinase inhibitors can inhibit the activity of BCR-ABL fusion protein to trigger the cells apoptosis, drug resistance or intolerance exists in part of CML patients. Arsenic sulfide in its raw form (r-As 4 S 4 ) can be orally administrated and certain therapeutic effects have been found out in the treatment of hematologic malignancies through inducing cell apoptosis. Methods In this work, a water-dissolvable arsenic sulfide nanoformualtion (ee-As 4 S 4 ) composed of As 4 S 4 particulates with 470 nm in diameter and encapsulated by a kind of hydrophilic polymer was fabricated and applied to the CML cell line K562, K562/AO2 and primary cells from the bone marrow of CML patients. Results Results showed that instead of inhibiting the activity of BCR-ABL, ee-As 4 S 4 induced direct degradation of BCR-ABL in K562 cells within 6 hr incubation, followed by the occurrence of erythroid differentiation in K562 after 72 hr incubation, evidenced by the significantly upregulated CD235a and benzidine staining, which was not detectable with r-As 4 S 4 . The ee-As 4 S 4 -induced erythroid differentiation was also observed in K562/AO2 cells and bone marrow mononuclear cells of CML patients. Mechanistic studies indicated that ee-As 4 S 4 induced autophagy by downregulating the level of intracellular ROS and hypoxia-inducible factor-1α significantly, which led to the subsequent degradation of BCR-ABL. When the concentration was increased, ee-As 4 S 4 induced much more significant apoptosis and cell cycle arrest than r-As 4 S 4 , and the cytotoxicity of the former was about 178 times of the latter. Conclusion ee-As 4 S 4 was capable of inducing significant erythroid differentiation of CML cells by inducing the direct degradation of BCR-ABL; the new effect could improve hematopoietic function of CML patients as well as inhibit the leukemic cell proliferation.

Increasing evidence shows that superparamagnetic scaffolds can enhance the osteogenesis under magnetic fields. The aim of this work is to compare the magnetization and the osteogenic enhancement of superparamagnetic scaffolds composed of different compositions with different microstructures. Herein 9 kinds of superparamagnetic scaffolds of PLA, polyurethane and gelatin were fabricated by incorporating iron oxide nanoparticles in polymeric matrices, and using the process of electrospinning, salt-leaching, and solution casting to obtain microstructure of nanofibrous, porous and smooth respectively, while hydroxyapatite nanoparticles were incorporated in all the scaffolds with the same percentage. It was showed that the magnetization behavior of the scaffolds was associated with the composition and microstructure as well as with the osteogenic enhancement of the scaffolds. The nanofibrous scaffold composed of PLA, nHA and MNPs possessed the strongest magnetization, and significantly promoted the osteogenic differentiation of pre-osteoblasts and bone marrow derived mesenchymal stem cells (bMSCs) under magnetic fields, evidenced by the upregulated gene expression of Runx2 and BMP2, the increased ALP activity, OPN and OCN of the cells. The optimal scaffold recruited more bMSCs and enhanced the osteogenic differentiation and the cross talk among the bMSCs, macrophages and fibroblasts under the magnetic field.