Hypoxic preconditioned aged BMSCs accelerates MI injury repair by modulating inflammation, oxidative stress and apoptosis.

The benefits of autologous cell therapy for cardiac repair are diminished in aged individuals due to the limited quality and poor tolerance of aged stem cells in the ischemic micro-environment. The safe and efficient methods to improve the therapeutic effect of aged stem cells are needed to treat the increasing number of aged patients with cardiac diseases. In the present study, we aimed to determine whether hypoxic preconditioning can improve the therapeutic effect of aged stem cells even if the responsiveness of aged MSCs is poor, and to seek the underlying mechanism. Using a murine model of MI, our results showed that hypoxic preconditioning promoted the therapeutic effect of aged BMSCs, which was expressed in improved cardiac function, decreased scar size and alleviated cardiac remodeling in vivo. This in vivo effect of hypoxic preconditioned aged BMSCs was associated with alleviated inflammation, oxidative stress and apoptosis in infarcted heart. In vitro studies confirmed that hypoxic preconditioned aged BMSCs exert cytoprotective impacts on H9C2 cells against lethal hypoxia injury via attenuating oxidative stress and apoptosis. Our data support the promise of hypoxic preconditioning as a potential strategy to improve autologous stem cell therapy for ischemic heart injury in aged individuals.

Relevance of two genes in the multidrug resistance of hepatocellular carcinoma: in vivo and clinical studies.

AIMS AND BACKGROUND: A former study evaluated the roles of four multidrug resistance-related proteins, namely multidrug resistance protein 1 (MDR1), breast cancer resistance protein (BCRP), multidrug resistance-related protein (MRP1), and lung resistance-related protein (LRP), in the MDR mechanism of the multidrug resistant hepatoma HepG2/ADM cell line and proposed that up-regulated MDR1 and BCRP are responsible for the MDR of hepatocellular carcinoma. This work aims to confirm that assumption in vivo and in clinical specimens. METHODS: First, the chemotherapeutic resistance of subcutaneous HepG2/ADM tumor and hepatocellular carcinoma samples post-transarterial chemoembolization (TACE) was determined by MTT, contrary to subcutaneous HepG2 tumor and hepatocellular carcinoma samples without TACE, respectively. Then, the mRNA and protein differential expression of the four genes between the MDR tissues and drug-sensitive tissues were quantitatively investigated by real-time RT-PCR and enhanced chemiluminescence western blot analysis, respectively. RESULTS: 1) mRNA expression of BCRP and MDR1 was respectively amplified 38.3 and 20.1 fold in tumors of HepG2/ADM mice compared to those of HepG2 mice, whereas they were respectively augmented for 14.6 and 9.3 times in TACE samples, contrary to the tumor tissues without TACE. 2) The protein presence of MDR1 and BCRP in MDR tumors was also significantly higher than those in the control group in vivo and in clinical specimens. 3) The mRNA expressions of MDR1 and BCRP were correlated to their protein levels. CONCLUSIONS: The study showed that MDR1 and BCRP may be the most important factors for drug resistance in hepatocellular carcinoma. Moreover, the positive correlation between their mRNA and protein expression indicates the easy prediction of HCC MDR and possible inhibitive target of drug resistance at multi-levels.

Synergism of hydroxyapatite nanoparticles and recombinant mutant human tumour necrosis factor-alpha in chemotherapy of multidrug-resistant hepatocellular carcinoma.

BACKGROUND/AIMS: Locoregional chemotherapy continues to be the mainstay for the treatment of unresectable hepatocellular carcinoma (HCC). One of the principal obstacles implicated in its unsuccessful therapy is multidrug resistance (MDR). Former studies have identified the multidrug-resistant nature and possible mechanisms of hepatoma cells both in vitro and in vivo. This work aimed to develop an effective strategy for the treatment of HCC with MDR. METHODS: The treatment was exploited to inhibit the MDR cells by co-administration of the recombinant mutant human tumour necrosis factor-alpha (rmhTNF-alpha), a sublethal dose of chemicals [adriamycin (ADM), mitomycin and 5-FU] and hydroxyapatite nanoparticles (nHAPs). Real-time quantitative reverse transcriptase-polymerase chain reaction and electrochemiluminescence Western blot were used to detect the expression of several related genes. RESULTS: The chemicals acted synergistically with rmhTNF-alpha and nHAP in suppressing the growth of hepatoma cells and inducing apoptosis of the cells, with the MDR phenotype reversed, as measured by intracellular ADM retention. Analysis of mRNA and protein revealed that rmhTNF-alpha inhibited the gene expression of XIAP, survivin, Ki67, PCNA, MDR1 and BCRP to some extent. Moreover, the inhibitory effects mentioned above could be as good or better than when nHAP is incorporated into the regimens. CONCLUSIONS: rmhTNF-alpha was not only able to restore the chemotherapeutic sensitivity to HepG2/ADM, its xenograft model and clinical samples but also further inhibited the growth of these tumours by a combination of nHAP. These results strongly suggested that chemicals in combination with rmhTNF-alpha and nHAP may be beneficial for the local treatment of advanced HCC.