A functionalized graphene oxide with improved cytocompatibility for stimuli-responsive co-delivery of curcumin and doxorubicin in cancer treatment.

Nowadays, the usage of nanoparticles in various fields such as drug delivery, attracts the attention of many researchers in the treatment of cancers. Graphene oxide (GO) is one of the novel drug delivery systems which is used broadly owing to its unique features. In this survey, doxorubicin (DOX) was accompanied by natural medicine, curcumin (CUR), to diminish its side effects and enhance its efficiency. Cytotoxicity assay in human gastric cancer (AGS), prostate cancer (PC3), and ovarian cancer (A2780), was evaluated. Also, the uptake of DOX and CUR into cells, was assessed using a fluorescence microscope. Moreover, real-time PCR was applied for the evaluation of the expression of RB1 and CDK2 genes, which were involved in the cell cycle. In both separate and simultaneous forms, DOX and CUR were loaded with high efficiency and the release behavior of both drugs was pH-sensitive. The higher release rate was attained at pH 5.5 and 42 °C for DOX (80.23%) and CUR (13.06), respectively. The intensity of fluorescence in the free form of the drugs, was higher than the loaded form. In the same concentration, the free form of CUR and DOX were more toxic than the loaded form in all cell lines. Also, free drugs showed more impact on the expression of RB1 and CDK2 genes. Co-delivery of CUR and DOX into the mentioned cell lines, was more effective than the free form of CUR and DOX due to its lower toxicity to normal cells.

Ginsenoside Rb1 Protects Human Umbilical Vein Endothelial Cells against High Glucose-Induced Mitochondria-Related Apoptosis through Activating SIRT3 Signalling Pathway.

OBJECTIVE: To investigate whether ginsenoside Rb1 (Rb1) can protect human umbilical vein endothelial cells (HUVECs) against high glucose-induced apoptosis and examine the underlying mechanism. METHODS: HUVECs were divided into 5 groups: control group (5.5 mmol/L glucose), high glucose (HG, 40 mmol/L) treatment group, Rb1 (50 µ mol/L) treatment group, Rb1 plus HG treatment group, and Rb1 and 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP, 16 µ mol/L) plus HG treatment group. Cell viability was evaluated by cell counting kit-8 assay. Mitochondrial and intracellular reactive oxygen species were detected by MitoSox Red mitochondrial superoxide indicator and dichloro-dihydro-fluorescein diacetate assay, respectively. Annexin V/propidium iodide staining and fluorescent dye staining were used to measure the apoptosis and the mitochondrial membrane potential of HUVECs, respectively. The protein expressions of apoptosis-related proteins [Bcl-2, Bax, cleaved caspase-3 and cytochrome c (Cyt-c)], mitochondrial biogenesis-related proteins [proliferator-activated receptor gamma coactivator 1-alpha, nuclear respiratory factor-1 and mitochondrial transcription factor A)], acetylation levels of forkhead box O3a and SOD2, and sirtuin-3 (SIRT3) signalling pathway were measured by immunoblotting and immunoprecipitation. RESULTS: Rb1 ameliorated survival in cells in which apoptosis was induced by high glucose (P<0.05 or P<0.01). Upon the addition of Rb1, mitochondrial and intracellular reactive oxygen species generation and malondialdehyde levels were decreased (P<0.01), while the activities of antioxidant enzymes were increased (P<0.05 or P<0.01). Rb1 preserved the mitochondrial membrane potential and reduced the release of Cyt-c from the mitochondria into the cytosol (P<0.01). In addition, Rb1 upregulated mitochondrial biogenesis-associated proteins (P<0.01). Notably, the cytoprotective effects of Rb1 were correlated with SIRT3 signalling pathway activation (P<0.01). The effect of Rb1 against high glucose-induced mitochondria-related apoptosis was restrained by 3-TYP (P<0.05 or P<0.01). CONCLUSION: Rb1 could protect HUVECs from high glucose-induced apoptosis by promoting mitochondrial function and suppressing oxidative stress through the SIRT3 signalling pathway.

Postexercise essential amino acid supplementation amplifies skeletal muscle satellite cell proliferation in older men 24 hours postexercise.

Aged skeletal muscle has an attenuated and delayed ability to proliferate satellite cells in response to resistance exercise. The mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is a focal point for cell growth, however, the effect of postexercise mTORC1 activation on human skeletal muscle satellite cell (SC) proliferation is unknown. To test the proliferative capacity of skeletal muscle SC in aging muscle to a potent mTORC1 activator (i.e., EAA; essential amino acids) we recruited older (~72y) men to conduct leg resistance exercise (8setsx10reps) without (-EAA; n = 8) and with (+EAA: n = 11) ingestion of 10 g of EAA 1 h postexercise. Muscle biopsies were taken before exercise (Pre) and 24 h postexercise (Post) for assessment of expression and fiber type-specific Pax7+ SC, Ki67+Pax7+ SC and MyoD+ SC -EAA did not show an increase in Pax7+ satellite cells at Post(P > 0.82). Although statistical significance for an increase in Pax7 +  SC at 24 h post-RE was not observed in +EAA versus -EAA, we observed trends for a treatment difference (P < 0.1). When examining the change from Pre to Post trends were demonstrated (#/myofiber: P = 0.076; and %/myonuclei: P = 0.065) for a greater increase in +EAA versus -EAA Notably, we found an increase SC proliferation in +EAA, but not -EAA with increase in Ki67+ SC and MyoD+ cells (P < 0.05). Ki67+ SC also exhibited a significant group difference Post (P < 0.010). Pax7+ SC in fast twitch myofibers did not change and were not different between groups (P > 0.10). CDK2, MEF2C, RB1 mRNA only increased in +EAA (P < 0.05). Acute muscle satellite cell proliferative capacity may be partially rescued with postexercise EAA ingestion in older men.

Palbociclib (PD-0332991), a selective CDK4/6 inhibitor, restricts tumour growth in preclinical models of hepatocellular carcinoma.

OBJECTIVE: Advanced hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. Palbociclib, a well-tolerated and selective CDK4/6 inhibitor, has shown promising results in the treatment of retinoblastoma (RB1)-positive breast cancer. RB1 is rarely mutated in HCC, suggesting that palbociclib could potentially be used for HCC therapy. Here, we provide a comprehensive characterisation of the efficacy of palbociclib in multiple preclinical models of HCC. DESIGN: The effects of palbociclib on cell proliferation, cellular senescence and cell death were investigated in a panel of human liver cancer cell lines, in ex vivo human HCC samples, in a genetically engineered mouse model of liver cancer, and in human HCC xenografts in vivo. The mechanisms of intrinsic and acquired resistance to palbociclib were assessed in human liver cancer cell lines and human HCC samples by protein and gene expression analyses. RESULTS: Palbociclib suppressed cell proliferation in human liver cancer cell lines by promoting a reversible cell cycle arrest. Intrinsic and acquired resistance to palbociclib was determined by loss of RB1. A signature of 'RB1 loss of function' was found in <30% of HCC samples. Palbociclib, alone or combined with sorafenib, the standard of care for HCC, impaired tumour growth in vivo and significantly increased survival. CONCLUSIONS: Palbociclib shows encouraging results in preclinical models of HCC and represents a novel therapeutic strategy for HCC treatment, alone or particularly in combination with sorafenib. Palbociclib could potentially benefit patients with RB1-proficient tumours, which account for 70% of all patients with HCC.

Characterization of a novel WDR5-binding site that recruits RbBP5 through a conserved motif to enhance methylation of histone H3 lysine 4 by mixed lineage leukemia protein-1.

Histone modification is well established as a fundamental mechanism driving the regulation of transcription, replication, and DNA repair through the control of chromatin structure. Likewise, it is apparent that incorrect targeting of histone modifications contributes to misregulated gene expression and hence to developmental disorders and diseases of genomic instability such as cancer. The KMT2 family of SET domain methyltransferases, typified by mixed lineage leukemia protein-1 (MLL1), is responsible for histone H3 lysine 4 methylation, a marker of active genes. To ensure that this modification is correctly targeted, a multiprotein complex associates with the methyltransferase and directs activity. We have identified a novel interaction site on the core complex protein WD repeat protein-5 (WDR5), and we mapped the complementary site on its partner retinoblastoma-binding protein-5 (RbBP5). We have characterized this interaction by x-ray crystallography and show how it is fundamental to the assembly of the complex and to the regulation of methyltransferase activity. We show which region of RbBP5 contributes directly to mixed lineage leukemia activation, and we combine our structural and biochemical data to produce a model to show how WDR5 and RbBP5 act cooperatively to stimulate activity.