Establishment of a low-tumorigenic MDCK cell line and study of differential molecular networks.

Influenza is an acute respiratory infection caused by the influenza virus, and vaccination against influenza is considered the best way to prevent the onset and spread. MDCK (Madin-Darby canine kidney) cells are typically used to isolate the influenza virus, however, their high tumorigenicity is the main controversy in the production of influenza vaccines. Here, MDCK-C09 and MDCK-C35 monoclonal cell lines were established, which were proven to be low in tumorigenicity. RNA-seq of MDCK-C09, MDCK-C35, and MDCK-W73 cells was performed to investigate the putative tumorigenicity mechanisms. Tumor-related molecular interaction analysis of the differentially expressed genes indicates that hub genes, such as CUL3 and EGFR, may play essential roles in tumorigenicity differences between MDCK-C (MDCK-C09 and MDCK-C35) and MDCK-W (MDCK-W73) cells. Moreover, the analysis of cell proliferation regulation-associated molecular interaction shows that downregulated JUN and MYC, for instance, mediate increased proliferation of these cells. The present study provides a new low-tumorigenic MDCK cell line and describes the potential molecular mechanism for the low tumorigenicity and high proliferation rate.

Effects of constraint-induced movement therapy on brain glucose metabolism in a rat model of cerebral ischemia: a micro PET/CT study.

PURPOSE: Constraint-induced movement therapy (CIMT) can improve motor functions in stroke patients and ischemic rats. This study examined the effect of CIMT in ischemic rats using positron emission tomography (PET). METHODS: We used middle cerebral artery occlusion (MCAO) procedure to induce cerebral ischemia in rats. Male rats were divided into a negative control group (Normal, n = 4), a sham-operated group (Sham, n = 6), an ischemic group (Control, n = 6) and an ischemic CIMT-treated group (CIMT, n = 6). CIMT started at postoperative day 8 (d8) and lasted for 2 weeks. We utilized 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) micro PET/CT imaging to evaluate glucose metabolism in different brain regions at baseline, before, and after treatment, respectively. RESULTS: CIMT improved behavioral performance in the ischemic CIMT group. At the end of treatment, the CIMT group showed lower standardized uptake values (SUVs) in the ipsilateral cingulate, motor and somatosensory cortex, respectively; as well as the anterodorsal hippocampus compared to the Control group (1.80% ± 0.10% vs. 1.92% ± 0.08%, 1.32% ± 0.14% vs. 1.48% ± 0.09%, 1.18% ± 0.14% vs. 1.42% ± 0.15%, 1.68% ± 0.09% vs. 1.79% ± 0.06%, P < 0.05). We also observed higher SUVs in the acbcore shell and cortex insular of the contralateral hemisphere compared to the Control group (2.07% group in the acbcore shell and cortex insular of contralateral P < 0.05). CONCLUSION: CIMT improved behavioral outcomes in cerebral ischemic rats and this effect can be attributed to increased glucose utilization in the contralateral hemisphere.

Co-delivery nanoparticles with characteristics of intracellular precision release drugs for overcoming multidrug resistance.

Combination chemotherapy in clinical practice has been generally accepted as a feasible strategy for overcoming multidrug resistance (MDR). Here, we designed and successfully prepared a co-delivery system named S-D1@L-D2 NPs, where denoted some smaller nanoparticles (NPs) carrying a drug doxorubicin (DOX) were loaded into a larger NP containing another drug (vincristine [VCR]) via water-in-oil-in-water double-emulsion solvent diffusion-evaporation method. Chitosan-alginate nanoparticles carrying DOX (CS-ALG-DOX NPs) with a smaller diameter of about 20 nm formed S-D1 NPs; vitamin E D-α-tocopheryl polyethylene glycol 1000 succinate-modified poly(lactic-co-glycolic acid) nanoparticles carrying VCR (TPGS-PLGA-VCR NPs) with a larger diameter of about 200 nm constituted L-D2 NPs. Some CS-ALG-DOX NPs loaded into TPGS-PLGA-VCR NPs formed CS-ALG-DOX@TPGS-PLGA-VCR NPs. Under the acidic environment of cytosol and endosome or lysosome in MDR cell, CS-ALG-DOX@TPGS-PLGA-VCR NPs released VCR and CS-ALG-DOX NPs. VCR could arrest cell cycles at metaphase by inhibiting microtubule polymerization in the cytoplasm. After CS-ALG-DOX NPs escaped from endosome, they entered the nucleus through the nuclear pore and released DOX in the intra-nuclear alkaline environment, which interacted with DNA to stop the replication of MDR cells. These results indicated that S-D1@L-D2 NPs was a co-delivery system of intracellular precision release loaded drugs with pH-sensitive characteristics. S-D1@L-D2 NPs could obviously enhance the in vitro cytotoxicity and the in vivo anticancer efficiency of co-delivery drugs, while reducing their adverse effects. Overall, S-D1@L-D2 NPs can be considered an innovative platform for the co-delivery drugs of clinical combination chemotherapy for the treatment of MDR tumor.

CS/PAA@TPGS/PLGA nanoparticles with intracellular pH-sensitive sequential release for delivering drug to the nucleus of MDR cells.

Development of novel nano-drug delivery systems (NDDS) that can transport anticancer drugs into cell nuclei is still a highly desirable strategy for reversing multi-drug resistance (MDR) in cancer therapy. Herein, we designed and prepared a novel NDDS, designated S@L NPs, in which several smaller nanoparticles are contained within a larger nanoparticle. Our S@L NPs (CS/PAA/VP-16@TPGS/PLGA NPs) possess a structure in which smaller nanoparticles (Chitosan-Poly(acrylic acid) nanoparticles, CS/PAA NPs) containing the drug etoposide (VP-16) are loaded within a larger nanoparticle (Vitamin E d-a-tocopheryl polyethylene glycol 1000 succinate-modified poly(lactic-co-glycolic acid) nanoparticles, TPGS/PLGA NPs). The system utilizes intracellular pH gradients to achieve pH-sensitive sequential release within different intracellular domains of MDR cells. S@L NPs could be triggered to degrade and release CS/PAA/VP-16 NPs in the acid environment of the cytosol, endosomes or lysosomes, and CS/PAA/VP-16 NPs were capable of entering the nucleus through nucleopores. It is significant that CS/PAA/VP-16 NPs exhibit disaggregation in the alkaline environment of the nucleus and thereby release the contained anticancer drug. Further mechanistic studies showed that CS/PAA/VP-16 NPs escaped retention and degradation within lysosomes and protected the drug from P-glycoprotein-induced efflux. Simultaneously, S@L NPs enhanced the anticancer effect of the loaded drug by inducing autophagy and apoptosis of MDR cells. This novel NDDS may provide a promising platform for nuclear drug delivery for reversing MDR.