The proto-oncogene c-Myc has a pivotal function in growth control, differentiation, and apoptosis and is frequently affected in human cancer, including breast cancer. Ubiquitin-specific protease 22 (USP22), a member of the USP family of deubiquitinating enzymes (DUBs), mediates deubiquitination of target proteins, including histone H2B and H2A, telomeric repeat binding factor 1, and cyclin B1. USP22 is also a component of the mammalian SAGA transcriptional co-activating complex. In this study, we explored the functional role of USP22 in modulating c-Myc stability and its physiological relevance in breast cancer progression. We found that USP22 promotes deubiquitination of c-Myc in several breast cancer cell lines, resulting in increased levels of c-Myc. Consistent with this, USP22 knockdown reduces c-Myc levels. Furthermore, overexpression of USP22 stimulates breast cancer cell growth and colony formation, and increases c-Myc tumorigenic activity. In conclusion, the present study reveals that USP22 in breast cancer cell lines increases c-Myc stability through c-Myc deubiquitination, which is closely correlated with breast cancer progression.

For sensors that emulate human tactile perception, we suggest a simple method for fabricating a highly sensitive force sensor using a conductive polyurethane sponge where graphene flakes are self-assembled into the porous structure of the sponge. The complete sensor device shows a sensitive and reliable detection response for a broad range of pressure and dynamic pressure that correspond to human tactile perception. Sensitivity of the sensor to detect vibration is also confirmed with vertical actuations due to slipping over micro-scale ridge structures attached on the sensors. Based on the sensor's ability to detect both pressure and vibration, the sensor can be utilized as a flexible tactile sensor.

Extracorporeal shock wave therapy (ESWT) considerably improves the appearance and symptoms of post-burn hypertrophic scars (HTS). However, the mechanism underlying the observed beneficial effects is not well understood. The objective of this study was to elucidate the mechanism underlying changes in cellular and molecular biology that is induced by ESWT of fibroblasts derived from scar tissue (HTSFs). We cultured primary dermal fibroblasts derived from human HTS and exposed these cells to 1000 impulses of 0.03, 0.1, and 0.3 mJ/mm2. At 24 h and 72 h after treatment, real-time PCR and western blotting were used to detect mRNA and protein expression, respectively, and cell viability and mobility were assessed. While HTSF viability was not affected, migration was decreased by ESWT. Transforming growth factor beta 1 (TGF-β1) expression was reduced and alpha smooth muscle actin (α-SMA), collagen-I, fibronectin, and twist-1 were reduced significantly after ESWT. Expression of E-cadherin was increased, while that of N-cadherin was reduced. Expression of inhibitor of DNA binding 1 and 2 was increased. In conclusion, suppressed epithelial-mesenchymal transition might be responsible for the anti-scarring effect of ESWT, and has potential as a therapeutic target in the management of post-burn scars.

Protein ubiquitination can be reversed by de-ubiquitinating enzymes (DUBs), which are classified into two main classes, cysteine proteases and metalloproteases. Cysteine proteases include ubiquitin-specific proteases (USPs) and ubiquitin C-terminal hydrolases. USP22 is a USP family member and a component of the mammalian Spt-Ada-Gcn5 acetyltransferase transcriptional coactivating complex. Regulator of calcineurin 1 (RCAN1; also known as DSCR1 or MCIP1) functions as an endogenous inhibitor of calcineurin signaling. In the present study, we have identified a novel interaction between USP22 and RCAN1 (RCAN1-1S) in the mammalian cells. In addition, the overexpression of USP22 caused the increase of RCAN1 protein stability. USP22 antagonized the actions of FBW7, NEDD4-2, and β-TrCP E3 ligase on RCAN1 and promoted RCAN1 de-ubiquitination. Moreover, we found that RCAN1 was bound to USP22 in basal conditions, and interferon-α (IFN-α) treatment caused the dissociation of RCAN1 from USP22, which subsequently triggered RCAN1 ubiquitination and proteasome degradation. Taken together, these results suggest that USP22 positively regulates RCAN1 levels, which would consequently affect diverse RCAN1-linked cellular processes, such as the inflammatory process involving the release of IFN-α.