Exosomes are nanoscale vectors with a diameter of 30~100 nm secreted by living cells, and they are important media for intercellular communication. Recent studies have demonstrated that exosomes can not only serve as biomarkers for diagnosis, but also have great potential as natural drug delivery vectors. Exosomes can be loaded with therapeutic cargos, including small molecules, proteins, and oligonucleotides. Meanwhile, the unique biological compatibility, high stability, and tumor targeting of exosomes make them attractive in future tumor therapy. Though exosomes can effectively deliver bioactive materials to receptor cells, there is a wide gap between our current understanding of exosomes and their application as ideal drug delivery systems. In this review, we will briefly introduce the function and composition of exosomes, and mainly summarize the potential advantages and challenges of exosomes as drug carriers. Finally, this review is expected to provide new ideas for the development of exosome-based drug delivery systems.
Objective To investigate the effects of the MKN-45 gastric cancer cell exosomes carrying microRNA-552 (miR-552) on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVEC). Methods ① The MKN-45 cells were divided into MKN-45 blank control group (no transfection), MKN-45 miR-552 inhibitor group [transfection of plasmid inhibiting mir-552 expression (mir-552 inhibitor plasmid)], and MKN-45 negative control group [transfection of negative control plasmid (empty plasmid)], the exosomes were extracted, purified, and identified. Western blotting was used to detect the protein expression of exosomal markers [CD63, CD9, and tumor susceptibility gene 101 (TSG101)]. ② The HUVEC cells were divided into HUVEC control group (added PBS), HUVEC-exosome group (co-cultured with exosomes of MKN-45 cell), HUVEC-negative control exosome group (co-cultured with exosomes of MKN-45 cell transfected with negative control plasmid), and HUVEC-miR-552 inhibitor exosome group (co-cultured with exosomes of MKN-45 cell transfected with miR-552 inhibitor plasmid), exosomes tracing experiment was used to detect whether exosomes entered HUVEC cells. Real-time fluorescent quantitative PCR method was used to detect the expression of miR-552, the MTT method was used to detect the proliferation of HUVEC cells, the Transwell chamber method was used to detect the migration of HUVEC cells, the angiogenesis test was used to detect the angiogenesis ability. Results This study successfully extracted exosomes from MKN-45 gastric cancer cells. Observed by transmission electron microscope, the exosomes were all round or elliptical, with a diameter of 100–150 nm, and the exosomal vesicle structure could be seen. Western blotting detection showed that the surface markers of exosomes (CD63, CD9, and TSG101 protein) were expressed in exosomes. The results of the tracing experiment showed that exosomes derived from MKN-45 cells were successfully internalized by HUVEC cells. After MKN-45 cells were transfected with miR-552 inhibitor plasmid, compared with the MKN-45 blank control group and MKN-45 negative control group, the relative expression level of miR-552 in the exosomes decreased (P<0.05). Compared with the HUVEC control group, the cell proliferation rate at 24, 48 and 74 h increased, as well as number of migration, tubule formation nodes, and relative expression level of miR-552 in the HUVEC-exosomes group increased (P<0.05). Compared with the HUVEC-negative control exosome group, the cell proliferation rate at 24, 48 and 74 h decreased, as well as the number of migration, tubule formation nodes, and relative expression level of miR-552 in the HUVEC-miR-552 inhibitor exosome group decreased (P<0.05). Conclusion The exosomes of gastric cancer cells carrying miR-552 can significantly promote the proliferation, migration, and angiogenesis of HUVEC cells.
ObjectiveTo summarize the molecular mechanisms and clinical treatment of gastric cancer with liver metastasis (GCLM), in order to provide new ideas for future treatment. MethodThe literatures about mechanism and treatment strategy of GCLM in recent years were searched and reviewed. ResultsMost patients with gastric cancer were in advanced stage or had developed distant metastases when they were first diagnosed, among which liver was the common site of metastasis. The complex molecular mechanisms of GCLM had not been fully clarified. Molecular mechanisms at different levels, including non-coding RNA, circulating tumor cells, exosomes, tumor microenvironment and signaling pathways, were relatively independent and interacted with each other, providing potential biomarkers and therapeutic targets for GCLM. At present, the best treatment method for patients with GCLM was mainly divided into local and systemic treatment. The local treatment included surgical treatment, radiofrequency ablation and proton beam therapy, while the systemic treatment included systemic chemotherapy, targeted therapy and immunotherapy, among which the targeted therapy and immunotherapy were the focus of recent research. ConclusionsThe mechanism of GCLM is the result of the interaction between tumor cells and the microenvironment at the site of metastasis. Understanding them is of great significance to guide clinical treatment and prognosis. At present, there is no unified treatment standard for GCLM. To achieve the ideal treatment effect, we should not only rely on single therapy, but also adopt multi-disciplinary and individual therapy according to the specific disease status of patients and the nature of tumors.
ObjectiveTo investigate the effect of adipose-derived stem cell derived exosomes (ADSC-Exos) on angiogenesis after skin flap transplantation in rats.MethodsADSCs were isolated and cultured by enzymatic digestion from voluntary donated adipose tissue of patients undergoing liposuction. The 3rd generation cells were observed under microscopy and identified by flow cytometry and oil red O staining at 14 days after induction of adipogenesis. After cells were identified as ADSCs, ADSC-Exos was extracted by density gradient centrifugation. And the morphology was observed by transmission electron microscopy, the surface marker proteins (CD63, TSG101) were detected by Western blot, and particle size distribution was measured by nanoparticle size tracking analyzer. Twenty male Sprague Dawley rats, weighing 250-300 g, were randomly divided into ADSC-Exos group and PBS group with 10 rats in each group. ADSC-Exos (ADSC-Exos group) and PBS (PBS group) were injected into the proximal, middle, and distal regions of the dorsal free flaps with an area of 9 cm×3 cm along the long axis in the two groups. The survival rate of the flap was measured on the 7th day, and then the flap tissue was harvested. The tissue morphology was observed by HE staining, and mean blood vessel density (MVD) was measured by CD31 immunohistochemical staining.ResultsADSCs were identified by microscopy, flow cytometry, and adipogenic induction culture. ADSC-Exos was a round or elliptical membrane vesicle with clear edge and uniform size. It has high expression of CD63 and TSG101, and its size distribution was 30-200 nm, which was in accordance with the size range of Exos. The distal necrosis of the flaps in the ADSC-Exos group was milder than that in the PBS group. On the 7th day, the survival rate of the flaps in the ADSC-Exos group was 64.2%±11.5%, which was significantly higher than that in the PBS group (31.0%±6.6%; t=7.945, P=0.000); the skin appendages in the middle region of the flap in the ADSC-Exos group were more complete, the edema in the proximal region was lighter and the vasodilation was more extensive. MVD of the ADSC-Exos group was (103.3±27.0) /field, which was significantly higher than that of the PBS group [(45.3±16.2)/field; t=3.190, P=0.011].ConclusionADSC-Exos can improve the blood supply of skin flaps by promoting the formation of neovascularization after skin flap transplantation, thereby improve the survival rate of skin flaps in rats.
Objective To investigate the effects of titanium modified by ultrasonic acid etching/anodic oxidation (UAT) loaded with endothelial progenitor cells-exosome (EPCs-exo) on proliferation and osteogenic and angiogenic differentiations of adipose-derived stem cells (ADSCs). Methods The adipose tissue and bone marrow of 10 Sprague Dawley rats were harvested. Then the ADSCs and EPCs were isolated and cultured by collagenase digestion method and density gradient centrifugation method, respectively, and identified by flow cytometry. Exo was extracted from the 3rd to 5th generation EPCs using extraction kit, and CD9 and CD81 were detected by Western blot for identification. The three-dimensional printed titanium was modified by ultrasonic acid etching and anodic oxidation to prepare the UAT. The surface characteristics of UAT before and after modification was observed by scanning electron microscopy; UAT was placed in EPCs-exo solutions of different concentrations (100, 200 ng/mL), and the in vitro absorption and release capacity of EPCs-exo was detected by BCA method. Then, UAT was placed in DMEM medium containing different concentrations of EPCs-exo (0, 100, 200 ng/mL), and co-cultured with the 3rd generation ADSCs to construct UAT-ADSCs-exo. Cell morphology by laser confocal microscopy, live/dead cell staining, and cell proliferation were observed to evaluate biocompatibility; alkaline phosphatase (ALP) staining and alizarin red staining, RT-PCR detection of osteogenesis-related genes [osteocalcin (OCN), RUNT-related transcription factor 2 (Runx2), ALP, collagen type 1 (COL-1)] and angiogenesis-related gene [vascular endothelial growth factor (VEGF)], immunofluorescence staining for osteogenesis (OCN)- and angiogenesis (VEGF)-related protein expression were detected to evaluate the effect on the osteogenic and angiogenic differentiation ability of ADSCs. Results Scanning electron microscopy showed that micro-nano multilevel composite structures were formed on the surface of UAT. About 77% EPCs-exo was absorbed by UAT within 48 hours, while EPCs-exo absorbed on the surface of UAT showed continuous and stable release within 8 days. The absorption and release amount of 200 ng/mL group were significantly higher than those of 100 ng/mL group (P<0.05). Biocompatibility test showed that the cells in all concentration groups grew well after culture, and the 200 ng/mL group was better than the other groups, with fully spread cells and abundant pseudopodia, and the cell count and cell activity were significantly higher than those in the other groups (P<0.05). Compared with the other groups, 200 ng/mL group showed enhanced ALP activity and mineralization ability, increased expressions of osteogenic and angiogenic genes (OCN, Runx2, COL-1, ALP, and VEGF), as well as increased expressions of OCN and VEGF proteins, with significant differences (P<0.05). Conclusion EPCs-exo can effectively promote the adhesion, proliferation, and osteogenic and angiogenic differentiation of ADSCs on UAT surface, the effect is the most significant when the concentration is 200 ng/mL.
ObjectiveTo summarize the relationship between exosome and thyroid diseases.MethodThe literatures reports on exosomes and the physiology, pathology and diseases of thyroid were collected and reviewed.ResultsExosomes were secreted by cells and could be found in various body fluids, which could mediate the normal physiological development of the thyroid gland and play an important role in the progression of Graves’ disease. Exosomes could be used as diagnostic and differential diagnostic biomarkers for thyroid cancer and affect the growth, invasion, and metastasis of thyroid cancer. As a drug carrier for anti-thyroid cancer, exosome had a good targeting ability.ConclusionExosomes play an important role in the development of various diseases of the thyroid gland, which have good application prospects in biomarkers for early diagnosis and prognostic evaluation, as well as targeted drug carriers for thyroid cancer.
ObjectiveTo understand the research progress of related biomarkers in early diagnosis of gastric cancer in recent years.MethodThe domestic and foregin literatures on studies of biomarkers of early diagnosis of gastric cancer in recent years were reviewed.ResultsAt present, the sensitivity and specificity of serum tumor biomarkers of gastric cancer such as CEA and CA19-9 were lower, so the molecular markers that could predict, screen, and diagnose gastric cancer in the early stage were further explored. The recent studies suggested that microRNAs, long non-coding RNAs, circular RNAs, exosome, etc. molecular markers in early diagnosis of gastric cancer had better prospects of clinilal application.ConclusionWith the continuous development of molecular biology technology, the values of microRNAs, long non-coding RNAs, circular RNAs, DNA, etc. in early diagnosis of gastric cancer would be further explored.
ObjectiveTo review the research progress in biotherapy of rotator cuff injury in recent years, in order to provide help for clinical decision-making of rotator cuff injury treatment. MethodsThe literature related to biotherapy of rotator cuff injury at home and abroad in recent years was widely reviewed, and the mechanism and efficacy of biotherapy for rotator cuff injury were summarized from the aspects of platelet-rich plasma (PRP), growth factors, stem cells, and exosomes. ResultsIn order to relieve patients’ pain, improve upper limb function, and improve quality of life, the treatment of rotator cuff injury experienced an important change from conservative treatment to open surgery to arthroscopic rotator cuff repair. Arthroscopic rotator cuff repair plus a variety of biotherapy methods have become the mainstream of clinical treatment. All kinds of biotherapy methods have ideal mid- and long-term effectiveness in the repair of rotator cuff injury. The biotherapy method to promote the healing of rotator cuff injury is controversial and needs to be further studied. ConclusionAll kinds of biotherapy methods show a good effect on the repair of rotator cuff injury. It will be an important research direction to further develop new biotherapy technology and verify its effectiveness.
ObjectiveTo investigate the effect of microRNA-135a (miR-135a) in human amnion mesenchymal stem cell exosome (hAMSC-Exo) on the migration of fibroblasts.MethodsThe hAMSC-Exo was extracted with exosomes separation kit and identified, the effect of hAMSC-Exo on fibroblasts migration was detected by scratch test. Real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the relative expression of miR-135a gene in hAMSC-Exo after overexpression of miR-135a. Scratch test was used to detect the effect of hAMSC-Exo on the migration of fibroblasts after overexpression and knockdown of miR-135a. Western blot was used to detect the migration related proteins of fibroblasts [large tumor suppressor 2 (LATS2), E-cadherin, N-cadherin, and α smooth muscle actin (α-SMA)] after overexpression and knockdown of miR-135a. The 293T cell exosomes and hAMSC-Exo were used as control.ResultshAMSC-Exos were extracted successfully. Scratch test results showed that hAMSC group had the strongest ability to promote fibroblasts migration, and GW4869 (exosome inhibitor) treatment group had reduced ability to promote fibroblasts migration. qRT-PCR test showed that the relative expression of miR-135a gene in hAMSC-Exo increased significantly after over expression of miR-135a. Scratch test results showed that after over expression of miR-135a, hAMSC-Exo enhanced the migration ability of fibroblasts, while after knockdown of miR-135a, hAMSC-Exo weakened the migration ability of fibroblasts. Western blot results showed that the expressions of E-cadherin, N-cadherin, LATS2 were down regulated and α-SMA was up regulated in each hAMSC-Exo treatment group when compared with 293T cell exosomes group; after over expression of miR-135a, hAMSC-Exo decreased the expressions of E-cadherin, N-cadherin, LATS2 and increased the expression of α-SMA; while after knockdown of miR-135a, the ability of hAMSC-Exo was weakened.ConclusionmiR-135a in hAMSC-Exo can promote fibroblasts’ migration, inhibit the expressions of E-cadherin, N-cadherin, LATS2, and promote the expression of α-SMA.
ObjectiveTo investigate the regulatory role of MSC-derived exosomes in obliterative bronchiolitis after lung transplantation. MethodsThe murine lung transplantation model was established with male C57BL/6 mice, and the mice were divided into a sham group (sham, n=6), a surgery group (OB, n=6), and a treatment group (OB+MSC-exo, n=6). The in vitro model was created by stimulating RAW264.7 with lipopolysaccharide+nigericin (LPS+Nigericin), and comprised a PBS group, a LPS+Nigericin group, and a LPS+Nigericin+MSC-exo group. Immunofluorescence and hematoxylin-eosin (HE) staining were used to analyze gasdermin D (GSDMD) expression, as well as lumen stenosis in lung grafts. Bioinformatics methods were employed to predict and screen target gene collagen type V alpha 1 (COL5A1). Q-PCR was used to measure mRNA expression levels of interleukin (IL)-1β, IL-18, IL-6, tumor necrosis factor-α (TNF-α), and COL5A1 in lung grafts and macrophages. Western blot was performed to detect Cleaved-Caspase 1 protein expression in lung grafts and GSDMD protein expression in macrophages. ResultsImmunofluorescence and HE staining revealed that in vivo infusion of MSC-exo reduced GSDMD expression in grafts, ameliorated tracheal epithelial cilia loss and lumen stenosis, and decreased Cleaved-Caspase 1 protein as well as IL-1β and IL-18 mRNA expression. MSC-exo treatment or COL5A1 knockdown reduced IL-1β, IL-18, IL-6, and TNF-α mRNA expression in macrophages, with comparable efficacy. MSC-exo infusion also decreased the number of COL5A1+ cells and mRNA expression levels in lung grafts. ConclusionMSC-derived exosomes alleviate obliterative bronchiolitis after lung transplantation by inhibiting COL5A1.