99mTc-radiolabeled HER2 targeted exosome for tumor imaging.

Exosomes represent unique features including nontoxicity, non-immunogenicity, biodegradability, and targeting ability that make them suitable candidates for clinical applications. Therefore, in this study, 99mTc-radiolabel HER2 targeted exosomes (99mTc-exosomes) were provided for tumor imaging. These exomes are obtained from genetically engineered cells and possessed DARPin G3 as a ligand for HER2 receptors. These exosomes were radiolabeled using fac-[99mTc(CO)3(H2O)3]+ synthon. The quality control showed high radiochemical purity (RCP) for 99mTc-exosomes (>96%). 99mTc-exosomes displayed a higher affinity toward SKOV-3 cells (higher HER2 expression) in comparison with MCF-7, HT29, U87-MG, A549 cell lines at different levels of HER2 expression. Trastuzumab (an antibody with a high affinity toward HER2) inhibited the binding of 99mTc-exosomes to SKOV-3 cells up to 40%. Biodistribution study in SKOV-3 tumor bearing nude mice confirmed the ability of 99mTc-exosomes for accumulation in the tumor. 99mTc-exosomes can visualize tumor in SKOV-3 tumor-bearing nude mouse. The blockage of HER2 receptors using trastuzumab (excessive amount) suggests the 99mTc-exosomes binding to the receptors and reduced the accumulation of 99mTc-exosomes in the tumor site. This suggest that 99mTc-exosomes interact with HER2 receptors and act through specific targeting.

Wnt-ß-catenin Signaling Pathway, the Achilles' Heels of Cancer Multidrug Resistance.

BACKGROUND: Most of the anticancer chemotherapies are hampered via the development of multidrug resistance (MDR), which is the resistance of tumor cells against cytotoxic effects of multiple chemotherapeutic agents. Overexpression and/or over-activation of ATP-dependent drug efflux transporters is a key mechanism underlying MDR development. Moreover, enhancement of drug metabolism, changes in drug targets and aberrant activation of the main signaling pathways, including Wnt, Akt and NF-κB are also responsible for MDR. METHODS: In this study, we have reviewed the roles of Wnt signaling in MDR as well as its potential therapeutic significance. Pubmed and Scopus have been searched using Wnt, ß-catenin, cancer, MDR and multidrug resistance as keywords. The last search was done in March 2019. Manuscripts investigating the roles of Wnt signaling in MDR or studying the modulation of MDR through the inhibition of Wnt signaling have been involved in the study. The main focus of the manuscript is regulation of MDR related transporters by canonical Wnt signaling pathway. RESULT AND CONCLUSION: Wnt signaling has been involved in several pathophysiological states, including carcinogenesis and embryonic development. Wnt signaling is linked to various aspects of MDR including P-glycoprotein and multidrug resistance protein 1 regulation through its canonical pathways. Aberrant activation of Wnt/ß- catenin signaling leads to the induction of cancer MDR mainly through the overexpression and/or over-activation of MDR related transporters. Accordingly, Wnt/ß-catenin signaling can be a potential target for modulating cancer MDR.

Targeted delivery of doxorubicin to HER2 positive tumor models.

BACKGROUND: Exosomes are natural nanovesicles with unique characteristics, such as long circulating half-life, the intrinsic ability to target tissues, biocompatibility, and minimal or no inherent systemic toxicity. Mesenchymal stem cells produce large amounts of exosomes with regenerative properties and more stability in human plasma. TUBO breast cancer cell lines overexpress rat HER2/neu protein. METHODS: Targeted exosomes were isolated from transduced bone marrow mesenchymal stem cells. Doxorubicin was encapsulated into exosomes by electroporation. Flow cytometry was used to assess the attachment of exosomes to the target cells. The in vitro cytotoxicity effect of targeted doxorubicin-loaded exosomes on TUBO cells was determined using MTT assay. Selective delivery of doxorubicin to tumor tissues was analyzed by measuring the auto-fluorescence of doxorubicin by in vivo imaging system. Moreover, tumor growth inhibition and body weight were monitored following injection of free doxorubicin, and targeted and untargeted doxorubicin-loaded exosomes in a TUBO breast cancer model. Finally, mouse tissues were examined for the presence of intrinsic fluorescence of doxorubicin. RESULTS: Flow cytometry results revealed significant differences in binding of targeted exosomes to HER2-positive (46.05%) and HER2-negative (13.9%) cells. The results of MTT assay showed that cytotoxicity of targeted doxorubicin-loaded exosomes was higher than free doxorubicin at 72 hours. Selective distribution of targeted doxorubicin-loaded exosomes in the target tissues of the murine breast cancer model suggested specific delivery of doxorubicin by targeted exosomes, rather than untargeted exosomes. Free doxorubicin and untargeted doxorubicin-loaded exosomes showed insignificant effects, whereas targeted doxorubicin-loaded exosomes reduced the tumor growth rate. CONCLUSION: Herein, we report efficient delivery of targeted doxorubicin-loaded exosomes in vitro, corroborated with a significant reduction of murine breast cancer model tumor growth rate.

Incorporated-bFGF polycaprolactone/polyvinylidene fluoride nanocomposite scaffold promotes human induced pluripotent stem cells osteogenic differentiation.

Bioactive scaffolds that can increase transplanted cell survival time at the defect site have a great promising potential to use clinically since tissue regeneration or secretions crucially depend on the transplanted cell survival. In this study embedded basic fibroblast growth factor (bFGF)-polycaprolactone-polyvinylidene fluoride (PCL-PVDF) hybrid was designed and fabricated by electrospinning as a bio-functional nanofibrous scaffold for bone tissue engineering. After morphological characterization of the PCL-PVDF (bFGF) scaffold, nanofibers biocompatibility was investigated by culturing of the human induced pluripotent stem cells (iPSCs). Then, the bone differentiation capacity of the iPSCs was evaluated when grown on the PCL-PVDF and PCL-PVDF (bFGF) scaffolds in comparison with culture plate as a control using evaluating of the common osteogenic markers. The viability assay displayed a significant increase in iPSCs survival rate when grown on the bFGF content scaffold. The highest alkaline phosphatase activity and mineralization were detected in the iPSCs while grown on the PCL-PVDF (bFGF) scaffolds. Obtained results from gene and protein expression were also demonstrated the higher osteoinductive property of the bFGF content scaffold compared with the scaffold without it. According to the results, the release of bFGF from PCL-PVDF nanofibers increased survival and proliferation rate of the iPSCs, which followed by an increase in its osteogenic differentiation potential. Taking together, PCL-PVDF (bFGF) nanofibrous scaffold demonstrated that can be noted as a promising candidate for treating the bone lesions by tissue engineering products.

A cell ELISA based method for exosome detection in diagnostic and therapeutic applications.

OBJECTIVE: Exosomes are nano-scaled carriers of miRNA, mRNA and proteins which are secreted from viable cells. Exosome detection within serum, saliva and semen offers diagnostic value for detection of various diseases including cancer. In the present study, we have lunched an in vitro study to develop a more efficient method for exosome detection. In this regard, the recombinant LAMP-DARPins (capable of Her2 targeting) gene was packed within the lentiviral particles and stably transferred into the HEK293T cells. The morphology and sizes of the obtained exosomes were characterized by TEM and zeta sizer. The expression of LAMP-DARPins antigen on the exosome surface was verified by western blotting. Ultimately, the efficiency of cell surface ELISA in suspension method was examined for exosome detection. RESULTS: The exosome particles were successfully harvested and purified from transfected cells. The sizes of exosome particles were determined to be 90 nm using zeta sizer instrument. The TEM scan showed that the exosomes are cap like shaped and their sizes range between 40 and 150 nm. An observed 120 kDa band on western blotting paper indicated the LAMP-DARPins antigen expression on exosome surfaces. The results of cell surface ELISA in suspension method were superior to the results of conventional cell ELISA. CONCLUSIONS: It could be concluded that the cell surface ELISA in suspension method could be an amenable method to detect exosome particles within the biological samples. Moreover, the method could be modified to evaluate the ability of exosomes to interact with target cells in both diagnostic and therapeutic applications.