5-Diphosphoinositol pentakisphosphate (IP7), formed by a family of inositol hexakisphosphate kinases (IP6Ks), has been demonstrated to be a physiologic inhibitor of Akt. IP6K inhibition may increase Akt activation in mesenchymal stem cells (MSCs), resulting in enhanced cardiac protective effect after transplantation. The aim of this study was to investigate the role of IP6Ks for improving MSCs' functional survival and cardiac protective effect after transplantation into infarcted mice hearts. Bone marrow-derived mesenchymal stem cells, isolated from dual-reporter firefly luciferase and enhanced green fluorescent protein positive (Fluc(+)-eGFP(+)) transgenic mice, were preconditioned with IP6Ks inhibitor TNP (0.5, 1, 5, and 10 μmol/L) for 2 h followed by 6 h of hypoxia and serum deprivation (H/SD) injury. TNP concentration dependently significantly decreased IP7 production with increased Akt phosphorylation. Moreover, TNP at 10 μmol/L significantly improved the viability and enhanced the paracrine effect of MSCs after H/SD. Furthermore, MSCs were transplanted into infarcted hearts with or without selective IP6Ks inhibition. Longitudinal in vivo bioluminescence imaging and immunofluorescent staining revealed that TNP pretreatment enhanced the survival of engrafted MSCs, which promoted the anti-apoptotic and pro-angiogenic efficacy of MSCs in vivo. Furthermore, MSC therapy with IP6Ks inhibition significantly decreased fibrosis and preserved heart function. This study demonstrates that inhibition of IP6Ks promotes MSCs engraftment and paracrine effect in infarcted hearts at least in part by down-regulating IP7 production and enhancing Akt activation, which might contribute to the preservation of myocardial function after MI.

IntroductionBone marrow-derived mesenchymal stem cells (BM-MSCs) have been proposed as an ideal autologous stem cell source for cell-based therapy for myocardial infarction (MI). However, decreased viability and impaired function of aged MSCs hampered the therapeutic efficacy of engrafted MSCs, and the underlying mechanisms remain unclarified. Here, we investigated the role of inositol phosphates 6 kinase (IP6Ks) inhibition on the therapeutic efficacy of BM-MSCs and its underlying mechanism.MethodsBM-MSCs isolated from young (8-week-old) or aged (18-month-old) donor male C57BL/6 mice, were subjected to hypoxia and serum deprivation (H/SD) injury with or without administration of inositol phosphates 6 kinase (IP6Ks) inhibitor TNP (10 μM). MSC apoptosis induced by H/SD was determined by flow cytometry and TUNEL assays. Protein expressions were evaluated by Western blot assay. Furthermore, the paracrine effects of MSCs were measured by reverse transcriptase–polymerized chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) analyses.ResultsAged BM-MSCs exhibited more Inositol pyrophosphate 7 (IP7) production, compared with young BM-MSCs. Meanwhile, the expression of phospho-Akt (Thr308) was significantly decreased in the aged MSCs, resulting in enhanced Bad activation and decreased Bax/Bcl-2 ratio. Moreover, the apoptosis in aged BM-MSCs was increased, compared with young BM-MSCs. Furthermore, TNP administration significantly inhibited IP7 production and increased the phosphorylation of Akt under both normoxic and hypoxic conditions. Meanwhile, IP6Ks inhibition reduced apoptotic index of aged MSCs, associated with decreased expressions of pro-apoptotic proteins Bax and Bad and increased anti-apoptotic protein Bcl-2. The expressions of angiogenic factors, including VEGF, bFGF, IGF-1 and HGF, were decreased in MSCs from aged mice. In addition, TNP administration enhanced the paracrine efficiency of aged BM-MSCs under normoxic and hypoxic conditions.ConclusionsThis study demonstrates for the first time that IP6Ks and IP7 play critical role in the aging related vulnerability to hypoxic injury and impaired paracrine efficiency of BM-MSCs, which is associated with impaired Akt activation.

Multidrug resistance (MDR) and targeted therapies present major challenges in tumor chemotherapy. Nanoparticles (NPs) hold promise for use in cancer theranostics due to their advantages in terms of tumor-targeted cytotoxicity and imaging. In this study, we developed N-((2-hydroxy-3-trimethylammonium) propyl) chitosan chloride (HTCC)/alginate-encapsulated Fe3O4 magnetic NPs (HTCC-MNPs) and applied them to MDR gastric cancer both in vivo and in vitro. HTCC-MNPs were fabricated from sodium alginate (ALG), Fe3O4 and HTCC using an ionic gelation method. The sizes and physical characteristics of the NPs were determined using dynamic light scattering, transmission electron microscopy (TEM) and zeta potential analysis. The HTCC-MNPs exhibited excellent water solubility and biocompatibility as well as significantly reduced cell viability in the drug-resistant cancer cell line SGC7901/ADR, but not in normal gastric cells (P < 0.05). An analysis of LC3 expression demonstrated the involvement of autophagy in HTCC-MNP cytotoxicity. Additionally, apoptosis was verified using a DNA content assay. HTCC-MNPs led to mitochondrial membrane potential loss, decreased ATP production and excessive reactive oxygen species (ROS) generation compared to a control group (P < 0.05). Magnetic resonance imaging showed enrichment of HTCC-MNPs in tumor-bearing mice. In vivo bioluminescence imaging and tumor volume measurements revealed that HTCC-MNPs markedly inhibited in vivo tumor growth (P < 0.05). In conclusion, HTCC-MNPs significantly inhibited MDR gastric tumor growth and reduced tumor volume via the induction of cellular autophagy and apoptosis, which was attributed to mitochondrial dysfunction and excessive ROS accumulation.

This study investigates the anti-cancer potential of Aclidinium bromide (INN) in glioblastoma. Glioblastoma cell lines U251 and U87 were treated with INN and its effects on cell migration and invasion were assessed by transwell migration and invasion assays., The effects of INN on proliferation and apoptosis were detected by CCK-8 kit and flow cytometry, and Western blotting determined anti-apoptotic proteins and signaling pathway changes. The results show that INN effectively suppressed proliferation, migration and invasion and induced apoptosis in U251 and U87 cells, respectively. Furthermore, the expression levels of the Bcl-2 anti-apoptotic protein was significantly decreased while Bax and caspase-3 expression were both increased in glioblastoma cells (all, p<0.05). Moreover, INN inactivated the PI3K/AKT signaling pathway by down-regulating the level of p-AKT, p-mTOR, P70 and CyclinD1 (all, p<0.05). In conclusion, our data suggests that INN could provide novel anticancer therapy in the treatment of glioblastoma.