Let-7a regulates EV secretion and mitochondrial oxidative phosphorylation by targeting SNAP23 in colorectal cancer.

BACKGROUND: MicroRNAs (miRNAs) are abundant in tumor-derived extracellular vesicles (EVs) and the functions of extracellular miRNA to recipient cells have been extensively studied with tumorigenesis. However, the role of miRNA in EV secretion from cancer cells remains unknown. METHODS: qPCR and bioinformatics analysis were applied for determining extracellular let-7a expression from CRC patient serum and cells. Nanosight particle tracking analysis was performed for investigating the effect of let-7a on EV secretion. Luciferase reporter assays was used for identifying targeted genes synaptosome-associated protein 23 (SNAP23). In vitro and in vivo assays were used for exploring the function of let-7a/SNAP23 axis in CRC progression. Bioenergetic assays were performed for investigating the role of let-7a/SNAP23 in cellular metabolic reprogramming. RESULTS: let-7a miRNA was elevated in serum EVs from CRC patients and was enriched in CRC cell-derived EVs. We determined that let-7a could suppress EV secretion directly targeting SNAP23. In turn, SNAP23 promotes EV secretion of let-7a to downregulate the intracellular let-7a expression. In addition, we found a novel mechanism of let-7a/SNAP23 axis by regulating mitochondrial oxidative phosphorylation (OXPHOS) through Lin28a/SDHA signaling pathway. CONCLUSIONS: Let-7a plays an essential role in not only inhibiting EV secretion, but also suppressing OXPHOS through SNAP23, resulting in the suppression of CRC progression, suggesting that let-7a/SNAP23 axis could provide not only effective tumor biomarkers but also novel targets for tumor therapeutic strategies.

Toll-like receptor 2 stimulation promotes colorectal cancer cell growth via PI3K/Akt and NF-κB signaling pathways.

Toll-like receptor (TLR) 2 is a key regulator of innate immune responses and has been shown to play an important role in inflammation-associated cancers. In this study, we aimed to evaluate the role of TLR2 in colorectal cancer (CRC). We demonstrated that TLR2 mRNA and protein expression was significantly upregulated in tumors from CRC patients and indicated poor prognosis. Using the TLR2 agonist Pam3Cys (P3C) to activate TLR2 signaling in human CRC cell lines, we showed that TLR2 drives cellular proliferation, which was dependent upon PI3K/Akt and NF-κB signaling pathways and was associated with the upregulation of anti-apoptotic genes BCL2A1, WISP1 and BIRC3. Likewise, pharmacological blockade of PI3K/Akt and NF-κB pathways mitigated the CRC pro-survival effects of TLR2 stimulation. Furthermore, genetic ablation of TLR2 using CRISPR/Cas9 suppressed CRC cell proliferation, invasion and migration. Taken together, these findings demonstrate that TLR2 plays an important role in colorectal tumorigenesis and may represent a promising therapeutic target in CRC.

Injectable photo crosslinked enhanced double-network hydrogels from modified sodium alginate and gelatin.

Recently, photocrosslinked hydrogels have attracted more and more attention in biomedical applications. In this study, a serials of injectable hydrogels were fabricated from aldehyde methacrylate sodium alginate and amino gelatin (AMSA/AG) using a two-step process. Here, sodium alginate, a kind of natural polysaccharide, was modified by oxidizer to form aldehyde sodium alginate (ASA), and methacrylate groups were further grafted on the main chain of ASA. Gelatin, the denatured form of collagen, was modified with ethylenediamine (ED) to graft more amino groups. When AMSA and AG aqueous solutions were mixed, the Schiff base reaction occurred quickly to form the primary network between aldehyde groups in AMSA and amino groups in AG, and then a 365nm ultraviolet (UV) light was used to initiate the radical reaction of methacrylate groups in AMSA to produce the secondary network. The structures and properties of AMSA/AG hydrogels were evaluated by Fourier Transforms Infrared spectroscopy (FTIR) and 1HNMR analysis. The swelling ratio confirmed the density of crosslinked networks, and the mechanical performance demonstrated that the UV initiated the double crosslinking network hydrogels have an improved mechanical properties compared to the single Schiff base networks hydrogels. The results showed that the photocrosslinked double network hydrogels have enhanced mechanical properties, good biocompatibility and controllable degradation rate. So, this hydrogels may have great potential utilized in regenerative medicine as therapeutic materials.

A thermosensitive chitosan-based hydrogel barrier for post-operative adhesions' prevention.

Post-operative peritoneal adhesions are common and serious complications for surgeons. They can cause pelvic pain, infertility, and potentially lethal bowel obstruction. We synthesized injectable hydrogels that formed by chemical modification through grafted hydrobutyl groups to chitosan chains. Gelation of hydroxybutyl chitosan (HBC) occurs in less than 60 s. Once formed, it can also be recovered completely. The residue time of hydrogels can extend to 4 weeks in Kunming mice. HBC hydrogels showed mild cytotoxicity to mice fibroblast cell (L929) and human vascular endothelial cell (ECV-304) in vitro and were biocompatible in the murine muscles, causing no adhesions for 4 weeks. HBC gels can form a durable barrier between defected cecum and abdominal wall. In a mice sidewall defect-bowel abrasion model, HBC gels showed significant efficacy in reducing adhesion formation.

Intraocular pressure and endothelium cell counts after cataract surgery with chitosan and sodium hyaluronate (Healon GV): 3-year follow-up results of a randomised clinical trial.

INTRODUCTION: The purpose of this study was to evaluate the long-term effects of chitosan 0.1% and sodium hyaluronate 1.4% (Healon GV(R); Advanced Medical Optics, Santa Ana, CA, USA) on intraocular pressure (IOP) and endothelial cell loss. METHODS: This randomised study comprised 140 eyes of 140 patients with age-related cataracts undergoing phacoemulsification followed by posterior chamber intraocular lens (IOL) implantation; 70 received chitosan 0.1%, and 70 received sodium hyaluronate 1.4%. The IOP was measured with standard Goldman applanation tonometry pre-operatively and 1 day, 1 week, 1 month, 3 months, 1 year and 3 years postoperatively. Endothelial cell counts were performed pre-operatively and 1 week, 1 month, 3 months, 1 year and 3 years postoperatively using a Pro/Koester WFSCM contact endothelial microscope. RESULTS: There were no significant differences found in postoperative IOP levels among the chitosan and sodium hyaluronate groups (P>0.05). No significant differences were found in postoperative mean endothelial cell counts at all time points between the chitosan and sodium hyaluronate groups (P>0.05). CONCLUSION: Chitosan has the same effects as sodium hyaluronate on IOP and endothelium cells counts after cataract surgery and IOL implantation, and therefore may be an alternative ophthalmic viscoelastic device.

[Serum hyaluronic acid, tumor necrosis factor -alpha, vascular endothelial growth factor, NO, and Se levels in adult patients with Kashin-Beck disease].

OBJECTIVE: To investigate the association of serum levels of hyaluronic acid (HA), tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), NO, and Se with the clinical manifestations in adult patients with Kashin-Beck disease (KBD). METHODS: Total 216 adults were selected for KBD screening from the KBD-prevalent areas in Yongshou county and the non-KBD areas of Chang'an county, Xi'an city, ShaanXi Province. According to the National Diagnostic Criteria of Kashin-Beck Disease in China, the diagnoses of KBD was established in 25 adult patients (11 men and 14 women, average age of 47.88+/-11.16 years), and 20 healthy control subjects from the KBD areas (8 men and 12 women, average age of 47.85+/-12.05 years) and 20 from the non-KBD areas (8 men and 12 women, average age of 47.45+/-11.24 years) were also selected to serve as controls. There was no significant difference in the average age and gender distribution between the 3 groups. The serum levels of HA, TNF-alpha, VEGF, NO and Se were measured by enzyme-linked immunosorbent assay, nitrate reductase method and griphite furnace atomic absorption spectrometry. RESULTS: Serum NO level was significantly higher in KBD group (41.7+/-21.89 micromol/L) than in the health controls from KBD areas (17.1+/-13.01 micromol/L) and non-KBD areas (17.58+/-11.48 micromol/l, F=13.11, df=2, P<0.001). Serum TNF-alpha level in KBD group (32.7+/-3.55 pg/ml) was significantly higher than that in the control subjects from the non-KBD areas (30.95+/-2.22 pg/ml, F=3.672, df=2, P=0.031), but similar with the control subjects from the KBD areas (32.7+/-3.55 pg/ml). Serum TNF-alpha and NO levels were identified as the indices that differed between adult KBD patients and the controls from both KBD and non-KBD areas by differential analysis (the function of differentiation was 0.062xNO+0.173xTNF -7.218). CONCLUSION: Serum TNF-alpha and NO levels are significantly increased in adult KBD patients and are associated with the clinical manifestations of KBD.

[Research of cross-linking reagent for producing hyaluronic acid derivative].

OBJECTIVE: To review the recent advances of cross-linking reagent for producing hyaluronic acid (HA) derivative so as to provide more advice for the development of HA reagent. METHODS: Recent original articles related to the species, characteristic, cross-linking methodology and mechanism of the cross-linking reagent to producing HA derivative were summarized and systematically analyzed. RESULTS: The derivatives after special kinds of reagents modification would remain their own good biocompatibility and change their original rheololgical characterization and obtain relative long organism residence time. CONCLUSION: Development of hyaluronic derivatives may widen their medical application.