Modulation of Synthetic Tracheal Grafts with Extracellular Matrix Coatings

Synthetic scaffolds for the repair of long-segment tracheal defects are hindered by insufficient biocompatibility and poor graft epithelialization. In this study, we determined if extracellular matrix (ECM) coatings improved the biocompatibility and epithelialization of synthetic tracheal grafts (syn-TG). Porcine and human ECM substrates (pECM and hECM) were created through the decellularization and lyophilization of lung tissue. Four concentrations of pECM and hECM coatings on syn-TG were characterized for their effects on scaffold morphologies and on in vitro cell viability and growth. Uncoated and ECM-coated syn-TG were subsequently evaluated in vivo through the orthotopic implantation of segmental grafts or patches. These studies demonstrated that ECM coatings were not cytotoxic and, enhanced the in vitro cell viability and growth on syn-TG in a dose-dependent manner. Mass spectrometry demonstrated that fibrillin, collagen, laminin, and nephronectin were the predominant ECM components transferred onto scaffolds. The in vivo results exhibited similar robust epithelialization of uncoated and coated syn-TG patches; however, the epithelialization remained poor with either uncoated or coated scaffolds in the segmental replacement models. Overall, these findings demonstrated that ECM coatings improve the seeded cell biocompatibility of synthetic scaffolds in vitro; however, they do not improve graft epithelialization in vivo.

Osteosarcoma-Derived Small Extracellular Vesicles Enhance Tumor Metastasis and Suppress Osteoclastogenesis by miR-146a-5p

Osteosarcoma is the most frequent type of primary bone tumor in children and adolescents, thus care for patients with malignant osteosarcoma is strongly required. The roles of small extracellular vesicles (SEVs) in enhancing metastases have been demonstrated in multiple tumors, but they are still poorly understood in osteosarcoma. Hence, this study investigated the effects of SEVs on progression and the tumor microenvironment in mice and patients. In an orthotopic implantation study, we found that osteosarcoma-derived SEVs had the potential to enhance metastases and angiogenesis. In addition, osteosarcoma-derived SEVs decreased the number of mature osteoclasts in vivo. In vitro osteoclastogenesis studies revealed that the inhibition of osteoclast maturation by osteosarcoma-derived SEVs was mediated by suppressing the NF-κB signal pathway. MicroRNA analysis of SEVs from different malignant human osteosarcomas revealed that miR-146a-5p was involved in the inhibition of osteoclastogenesis. In osteosarcoma patients, lower numbers of osteoclasts in biopsy specimens at the first visits were correlated with higher malignancy. These findings indicated that osteosarcoma-derived SEVs enhance distant metastasis of osteosarcomas by inhibiting osteoclast maturation, which may be a useful prognostic marker. This diagnostic method may enable to predict malignancy at early stage, and help to provide optimal care to patients with risk of high malignancy.

Resveratrol Derivative, Trans-3, 5, 4 ′ -Trimethoxystilbene Sensitizes Osteosarcoma Cells to Apoptosis via ROS-Induced Caspases Activation

Numerous studies have shown that resveratrol can induce apoptosis in cancer cells. Trans-3, 5, 4 ′ -trimethoxystilbene (TMS), a novel derivative of resveratrol, is a more potent anticancer compound than resveratrol and can induce apoptosis in cancer cells. Herein, we examined the mechanisms involved in TMS-mediated sensitization of human osteosarcoma (143B) cells to TNF-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis. Our results showed that cotreatment with TSM and TRAIL activated caspases and increased PARP-1 cleavage in 143B cells. Decreasing cellular ROS levels using NAC reversed TSM- and TRAIL-induced apoptosis in 143B cells. NAC abolished the upregulated expression of PUMA and p53 induced by treatment with TRAIL and TSM. Silencing the expression of p53 or PUMA using RNA interference attenuated TSM-mediated sensitization of 143B cells to TRAIL-induced apoptosis. Knockdown of Bax also reversed TSM-induced sensitization of 143B cell to TRAIL-mediated apoptotic cell death. These results indicate that cotreatment with TRAIL and TSM evaluated intracellular ROS level, promoted DNA damage, and activated the Bax/PUMA/p53 pathway, leading to activation of both mitochondrial and caspase-mediated apoptosis in 143B cells. Orthotopic implantation of 143B cells in mice also demonstrated that cotreatment with TRAIL and TSM reversed resistance to apoptosis in cells without obvious adverse effects in normal cells.

A triple-negative matrix-producing breast carcinoma is arrested by tumor-targeting Salmonella typhimurium A1-R in a PDOX model

ABSTRACTBackground/AimMatrix-producing breast carcinoma (MPBC), is a rare, recalcitrant and highly aggressive. The present study aimed to determine the efficacy of tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R on a triple-negative MPBC in a patient-derived orthotopic xenograft (PDOX) model.MethodsThe PDOX model was established in the left second mammary gland of a nude mouse by surgical orthotopic implantation (SOI) of the patient triple-negative MPBC PDOX models were randomized into two groups: G1, control group (n=6); G2, tumor-targeting S. typhimurium A1-R group (n=7, intravenous (i.v.) injection via tail vein, weekly, for two weeks). All mice were sacrificed on day 15. Tumor volume and body weight were measured one time per week.ResultsS. typhimurium A1-R arrested tumor growth compared to the control group (P = 0.016).ConclusionThe results of the present study suggest that S. typhimurium A1-R has future clinical potential in triple-negative MPBC patients.

Regeneration of partially decellularized tracheal scaffolds in a mouse model of orthotopic tracheal replacement

Decellularized tracheal scaffolds offer a potential solution for the repair of long-segment tracheal defects. However, complete decellularization of trachea is complicated by tracheal collapse. We created a partially decellularized tracheal scaffold (DTS) and characterized regeneration in a mouse model of tracheal transplantation. All cell populations except chondrocytes were eliminated from DTS. DTS maintained graft integrity as well as its predominant extracellular matrix (ECM) proteins. We then assessed the performance of DTS in vivo. Grafts formed a functional epithelium by study endpoint (28 days). While initial chondrocyte viability was low, this was found to improve in vivo. We then used atomic force microscopy to quantify micromechanical properties of DTS, demonstrating that orthotopic implantation and graft regeneration lead to the restoration of native tracheal rigidity. We conclude that DTS preserves the cartilage ECM, supports neo-epithelialization, endothelialization and chondrocyte viability, and can serve as a potential solution for long-segment tracheal defects.