The transduction of His-TAT-p53 fusion protein into the human osteogenic sarcoma cell line (Saos-2) and its influence on cell cycle arrest and apoptosis

Deacetyl epoxyazadiradione protects aminoglycoside antibiotic-induced renal cell apoptosis, in vitro

Aminoglycoside antibiotics such as gentamicin are used frequently to treat bacterial infections in humans. Excessive consumption of these antibiotics lead to renal dysfunction. One of the factors contributing to renal dysfunction is oxidative damage, which causes apoptosis. Hence, this study investigates the effect of the antioxidant compound deacetyl epoxyazadiradione (DEA) in reducing cell death induced by gentamicin treatment in kidney cells (Madin-Darby canine kidney cells). The antioxidant experiments showed that reactive oxygen species level is decreased up to 27.06 ± 0.18% in 150 µM of DEA treatment. At this concentration, the activity of antioxidant enzymes such as superoxide dismutase increased from 0.4 ± 0.04 to 1.46 ± 0.05 µmol/min/L and catalase increased from 7.48 ± 0.39 to 17.6 ± 0.74 U/mg. The relative folds of gene expression of mitochondrial enzymes such as GST, GPx and GR restored from 0.596 ± 0.019, 0.521 ± 0.013 and 0.775 ± 0.014 to 0.866 ± 0.013, 0.669 ± 0.015 and 0.8615 ± 0.028, respectively. Consequently, the percentage of cell viability increases upto 91.8 ± 2.01 from 61.93 ± 1.63 with much less fragmentation in genomic DNA. Additionally, molecular docking results showed that DEA could bind to Bax, Bcl- 2, Caspase- 3 and Caspase- 9 proteins. These results indicate that DEA could reduce cell apoptosis by reducing oxidative stress due to antibiotics and interrupting the apoptotic signal pathway in kidney cells.

AdipoRon Affects Cell Cycle Progression and Inhibits Proliferation in Human Osteosarcoma Cells

AdipoRon (AdipoR) is the first synthetic molecule acting as a selective and potent adiponectin receptor agonist. Recently, the possible pharmacological use of AdipoR in different pathological conditions has been addressed. Interestingly, initial evidence suggests that AdipoR may have anticancer properties in different preclinical models, such as pancreatic and ovarian cancer. To our knowledge, so far no research has been directed at determining the impact of AdipoR on osteosarcoma, the most aggressive and metastatic bone malignancy occurring in childhood and adolescence age. Here, we investigate the possible antitumor effects of AdipoR in osteosarcoma cell lines. MTT and cell growth curve assays clearly indicate that AdipoR inhibits, at different extents, proliferation in both U2OS and Saos-2 osteosarcoma cell lines, the latter being more sensitive. Moreover, flow cytometry-based assays point out a significant G0/G1 phase accumulation and a contemporary S phase decrease in response to AdipoR. Consistent with the different sensitivity, a strong subG1 appearance in Saos-2 after 48 and 72 hours of treatment is also observed. The investigation of the molecular mechanisms highlights a common and initial ERK1/2 activation in response to AdipoR in both Saos-2 and U2OS cells. Interestingly, a simultaneous and dramatic downregulation of p70S6K phosphorylation, one of the main targets of mTORC1 pathway, has also been observed in AdipoR-treated Saos-2, but not in U2OS cells. Importantly, a strengthening of AdipoR-induced effects was reported upon everolimus-mediated mTORC1 perturbation in U2OS cells. In conclusion, our findings provide initial evidence of AdipoR as an anticancer molecule differently affecting various signaling pathways involved in cell cycle and cell death in osteosarcoma cells and encourage the design of future studies to further understand its pattern of activities.

Secretory TAT-peptide-mediated protein transduction of LIF receptor α-chain distal cytoplasmic motifs into human myeloid HL-60 cells

The distal cytoplasmic motifs of leukemia inhibitory factor receptor α-chain (LIFRα-CT3) can independently induce intracellular myeloid differentiation in acute myeloid leukemia (AML) cells by gene transfection; however, there are significant limitations in the potential clinical use of these motifs due to liposome-derived genetic modifications. To produce a potentially therapeutic LIFRα-CT3 with cell-permeable activity, we constructed a eukaryotic expression pcDNA3.0-TAT-CT3-cMyc plasmid with a signal peptide (ss) inserted into the N-terminal that codes for an ss-TAT-CT3-cMyc fusion protein. The stable transfection of Chinese hamster ovary (CHO) cells via this vector and subsequent selection by Geneticin resulted in cell lines that express and secrete TAT-CT3-cMyc. The spent medium of pcDNA3.0-TAT-CT3-cMyc-transfected CHO cells could be purified using a cMyc-epitope-tag agarose affinity chromatography column and could be detected via SDS-PAGE, with antibodies against cMyc-tag. The direct administration of TAT-CT3-cMyc to HL-60 cell culture media caused the enrichment of CT3-cMyc in the cytoplasm and nucleus within 30 min and led to a significant reduction of viable cells (P < 0.05) 8 h after exposure. The advantages of using this mammalian expression system include the ease of generating TAT fusion proteins that are adequately transcripted and the potential for a sustained production of such proteins in vitro for future AML therapy.

Temporal Requirements of cMyc Protein for Reprogramming Mouse Fibroblasts

Exogenous expression of Oct4, Sox2, Klf4, and cMyc forces mammalian somatic cells to adopt molecular and phenotypic characteristics of embryonic stem cells, commencing with the required suppression of lineage-associated genes (e.g., Thy1 in mouse). Although omitting cMyc from the reprogramming cocktail minimizes risks of uncontrolled proliferation, its exclusion results in fold reductions in reprogramming efficiency. Thus, the feasibility of substituting cMyc transgene with (non-integrative) recombinant “pTAT-mcMyc” protein delivery was assessed, without compromising reprogramming efficiency or the pluripotent phenotype. Purification and delivery of semisoluble/particulate pTAT-mcMyc maintained Oct4-GFP⁺ colony formation (i.e., reprogramming efficiency) whilst supporting pluripotency by various criteria. Differential repression of Thy1 by pTAT-mcMyc ± Oct4, Sox2, and Klf4 (OSK) suggested differential (and non-additive) mechanisms of repression. Extending these findings, attempts to enhance reprogramming efficiency through a staggered approach (prerepression of Thy1) failed to improve reprogramming efficiency. We consider protein delivery a useful tool to decipher temporal/molecular events characterizing somatic cell reprogramming.

PTD4-apoptin protein therapy inhibits tumor growth in vivo

Apoptin protein harbors tumor-selective cell death activity, which makes it a potential anticancer therapy candidate. This study reports an apoptin therapy approach based on protein transduction domain 4 (PTD4)-mediated transduction of recombinant apoptin protein. In vitro, the PTD4-apoptin fusion protein is located in the nucleus and induces cell death in, e.g., human hepatocarcinoma HepG2 cells. In normal human L-02 hepatocytes, PTD4-apoptin protein retained mainly cytoplasmic and did not induce detectable levels of cell death, illustrating that the PTD4 domain does not affect apoptin's tumor-selective characteristics. In vivo, liver, cervix and gastric carcinoma xenografts treated with PTD4-apoptin protein for 6 days via the tumor epidermis exhibited a significant tumor growth inhibition because of apoptin-mediated cell death. In addition, treatment of human hepatocarcinoma xenografts during 3 weeks showed that PTD4-apoptin protein has significant anticancer activity, whereas control treatment with PTD4-enhanced green fluorescence protein or saline did not. Cell death and disruption of the tumor integrity were apparent in the PTD4-apoptin transduced xenografted tumors. As important, although PTD4-apoptin protein could be detected in the epidermal tissue covering the subcutaneous tumor tissue and in several organs, such as liver and brain, of the treated mice, no tissue disruption or signs of cell death could be detected. Our in vivo data reveal that apoptin protein delivery constitutes a novel powerful and safe anticancer therapy.