Increased 20S Proteasome Expression and the Effect of Bortezomib during Cisplatin-Induced Muscle Atrophy.

Cisplatin is a chemotherapy drug used to treat a variety of cancers. Muscle loss in cancer patients is associated with increased cancer-related mortality. Previously, we suggested that cisplatin administration increases the atrophic gene expressions of ubiquitin E3 ligases, such as atrogin-1 and muscle RING finger-1 (MuRF1), which may lead to muscle atrophy. In this study, C57BL/6J mice were treated with cisplatin (3 mg/kg, intraperitoneally) or saline for 4 consecutive days. Twenty-four hours after the final injection of cisplatin, quadriceps muscles were removed from the mice. The gene expression of Psma and Psmb, which comprise the 20S proteasome, was upregulated by cisplatin administration in the quadriceps muscle of mouse. Systemic administration of cisplatin significantly reduced not only the quadriceps muscle mass but also the diameter of the myofibers. In addition, bortezomib (0.125 mg/kg, intraperitoneally) was administered 30 min before each cisplatin treatment. The co-administration of bortezomib, a proteasome inhibitor, significantly recovered the reductions in the mass of quadriceps and myofiber diameter, although it did not recover the decline in the forelimb and forepaw strength induced by cisplatin. Increased 20S proteasome abundance may play a significant role in the development of cisplatin-induced muscle atrophy. During cisplatin-induced skeletal muscle atrophy, different mechanisms may be involved between loss of muscle mass and strength. In addition, it is suggested that bortezomib has essentially no effect on cisplatin-induced muscle atrophy.

Eicosapentaenoic acid suppresses cisplatin-induced muscle atrophy by attenuating the up-regulated gene expression of ubiquitin.

Previously it was shown that cisplatin causes muscle atrophy. Under this condition, cisplatin increased the expression of atorogenes, such as muscle ring finger 1 and atrogin-1 (also known as muscle atrophy F-box protein), in mouse skeletal muscle. It was reported recently that ubiquitin (Ub) and ubiquitinated protein levels in skeletal muscle were also up-regulated in cisplatin-induced muscle atrophy, and cisplatin-induced ubiquitinated proteins were degraded by the 26S proteasome pathway. Eicosapentaenoic acid (EPA) is effective against skeletal muscle atrophy in mice. However, it is unclear how EPA suppresses the Ub-proteasome pathway. In this study, the effect of EPA on cisplatin-induced muscle atrophy in mice was examined. Mice were intraperitoneally injected with cisplatin or vehicle control once daily for 4 d. EPA or its vehicle was orally administered 30 min before cisplatin administration. Cisplatin systemic administration induced decrease in muscle mass, myofiber diameter, and increase in Ub genes and ubiquitinated proteins in mouse skeletal muscle were recovered by co-treatment with EPA. However, weight loss and up-regulated atrogenes induced by cisplatin were not changed by co-treatment with EPA in skeletal muscle. In this study, EPA attenuated cisplatin-induced muscle atrophy via down-regulation of up-regulated Ub gene expression. Although further clinical studies are needed, EPA administration can be effective in the development of muscle atrophy in cisplatin-treated patients.

Upregulation of ubiquitinated proteins and their degradation pathway in muscle atrophy induced by cisplatin in mice.

We previously demonstrated that cisplatin administration in mice induces muscle atrophy and an increase in the expression of two muscle-specific ubiquitin E3 ligase genes, muscle ring finger protein 1 (MuRF1), and atrophy gene-1 (atrogin-1), in skeletal muscle. Ubiquitination serves as a degradation signal in both the ubiquitin-proteasome and selective autophagy pathways. In the present study, we investigated changes in the expression of ubiquitin and ubiquitinated proteins and their degradation pathways. Ubiquitin and ubiquitinated protein levels were increased by cisplatin compared with those in the vehicle and dietary restriction (DR) groups. To quantify the levels of ubiquitin and ubiquitinated proteins, we conducted a dot blot assay using an anti-ubiquitin antibody. The expression of ubiquitin was also significantly increased by cisplatin compared with that in the vehicle and DR groups. Since the ubiquitin proteins were upregulated by cisplatin, we measured the mRNA levels of the ubiquitin genes: Ubb, Ubc, Rps27a, and Uba52. All these four genes were increased by cisplatin administration compared with those in both the vehicle-treated and DR groups in quadriceps muscle tissue. The anti-ubiquitin antibody-sensitive bands increased when C2C12 myotubes were treated with cisplatin. Furthermore, MG-132 (26 s proteasome inhibitor), but not bafilomycin A1 (autophagy inhibitor), caused a further increase in expression. In conclusion, ubiquitin and ubiquitinated proteins are upregulated in cisplatin-induced muscle atrophy. Cisplatin-induced ubiquitinated proteins are degraded by the 26 s proteasome pathway.

[Verification of reduction in preparation time and cost of cyclophosphamide when using the closed-system drug transfer device].

The closed-system transfer device (CSTD), which is used to prevent the exposure of medical staff to anticancer drugs, has been reported to allow safe preparation and administration of these drugs to patients. At many medical institutions, however, the use of such devices is limited to select anticancer drugs. This could be attributable to the longer preparation time compared to the conventional injection technique with a syringe and needle, as well as the fact that the anticancer drugs are too expensive to be covered by the remuneration available for medical services. Against this background, we measured the time required to prepare cyclophosphamide(CPA)and estimated the cost incurred. Our results indicated that the preparation time for either a single dose of 100 mg CPA or a combination of 100 mg CPA and 500 mg of another drug(100mg+500 mg group)was significantly longer than that for 500 mg of a single drug. On the other hand, use of a CSTD reduced the total cost (drug cost+CSTD cost)on switching to a single dose of 500 mg, resulting in a 5-year savings as follows: 3,755,217 yen for ChemoCLAVE®, 6,302,622 yen for PhaSeal®, and 2,698,451 yen for Chemosafe®. These findings suggest that the appropriate selection of drugs, including a large standard dose of CPA, allows shortened preparation time and reduced total drug cost as well as CSTD cost.

[Comparative examination of preparation time in docetaxel hydrate formulation].

Docetaxel hydrate(DTX), a taxane anticancer drug, is known to be effective against a wide range of cancers, including breast cancer and non-small cell lung cancer. The DTX preparation Taxotere(2-vial DTX)has conventionally required dissolution in the attached solvent, while Onetaxotere(1-vial DTX), a newer product, is provided as a solution. This allows reduction of preparation time, so that improvement in operational efficiency can be expected. In this study, we measured the actual preparation time for 2-vial DTX and 1-vial DTX to compare their usefulness. The median preparation time for 2-vial DTX(n=84)and 1-vial DTX(n=84)was significantly different, with the respective values being 6. 52 minutes and 2. 67 minutes(p<0. 01). By switching to 1-vial DTXfrom 2-vial DTX, which requires preparation of a premix solution with the attached solvent, the preparation procedure in daily practice becomes more convenient. This is because of a shorter preparation time as well as a lower risk of contamination, suggesting the usefulness of 1-vial DTX.

[Expression of allergic reactions to oxaliplatin].

Oxaliplatin (L-OHP), a platinum-containing antineoplastic agent, is a key drug for the treatment of colorectal cancer. However, it is often difficult to continue with its treatment because of the expression of allergic reactions. This study was an investigation of the expression of allergic reactions resulting from administration of L-OHP. A retrospective analysis was performed on patients undergoing therapeutic regimens including L-OHP, from April 2009 to November 2010 in Juntendo University Urayasu Hospital. The results showed that allergic reactions were expressed in 15 out of 81 patients (18. 5%). A high correlation was found between the time from administration until expression of the allergic reaction, and the number of treatment courses (r=-0. 521, p=0. 047). When patient characteristics were compared between the allergic reaction group and the no-reaction group, it was suggested that differences due to the regimen or the presence or absence of liver metastasis, which is considered to be related to drug metabolism, had no effect. Items showing significant differences were sexual difference(p=0. 022)and the effect of changes depending on the dose form of L-OHP(p=0. 003). It was possible to continue treatment with L-OHP in six patients even after expression of allergic reactions. Anti-allergy measures such as additional administration of steroids or antihistamines were suggested to be useful for continuing treatment.

Efficiency of cell-penetrating peptides on the nasal and intestinal absorption of therapeutic peptides and proteins.

The purpose of our study was to investigate the potential of cell-penetrating peptides; penetratin as novel delivery vector, on the systemic absorption of therapeutic peptides and proteins across different mucosal administration sites. The absorption-enhancing feasibility of l- and d-penetratin (0.5mM) was used for glucagon-like peptide-1 (GLP-1), and exendin-4 as novel antidiabetic therapy, in addition to interferon-beta (IFN-beta) as protein biotherapeutic model from nasal and intestinal route of administration was evaluated as first time in rats. Nasal route is the most feasible for the delivery of therapeutic peptides coadministered with penetratin whereas the intestinal route appears to be more restricted. The absolute bioavailability (BA (%)) values depend on the physichochemical characters of drugs, stereoisomer character of penetratin, and site of administration. Penetratin significantly increased the nasal more than intestinal absorption of GLP-1 and exendin-4, as the BA for nasal and intestinal administration of GLP-1 was 15.9% and 5%, and for exendin-4 were 7.7% and 1.8%, respectively. Moreover, the BA of IFN-beta coadministered with penetratin was 11.1% and 0.17% for nasal and intestinal administration, respectively. From these findings, penetratin is a promising carrier for transmucosal delivery of therapeutic peptides and macromolecules as an alternative to conventional parenteral routes.