Apoptosis-related Proteins Are Altered by Selective Tyrosine Kinase Inhibitors and Everolimus in HPV-dependent SCC.

BACKGROUND: Head and neck squamous cell cancer (HNSCC) affects the oral cavity and the pharynx. The aim of the study was to investigate the effects of selective tyrosine kinase inhibitors (TKIs) erlotinib, gefitinib, nilotinib and dasatinib and the mammalian target of rapamycin (mTOR) inhibitor everolimus on the expression of apoptosis-related proteins caspase-3, FAS cluster of differentiation (CD)-95 and FAS ligand in human papilloma virus (HPV)-dependent squamous cancer. MATERIALS AND METHODS: Two HPV-negative cell lines (UMSCC-11A/-14C) and one HPV-positive cell line (CERV196) were incubated with TKIs or everolimus and protein concentrations of target proteins were analyzed with enzyme-linked immunosorbent assay (ELISA). RESULTS: Caspase-3 was affected by the tested TKIs in HPV-positive SCC, whereas FAS CD95 and FAS ligand were influenced in HPV-negative SCC. DISCUSSION: This is the first study to analyze the influence of TKIs and everolimus on key proteins of apoptosis. Our results provide novel information contributing to a better understanding of the cell biology of HPV-dependent HNSCC and might contribute to the discovery of novel pharmaceutical treatment strategies for HNSCC.

Influence of static magnetic fields on human myoblast/mesenchymal stem cell co­cultures.

The results of surgical repair of extensive muscle tissue defects are still of primary concern, leaving patients with residual cosmetic and functional impairments. Therefore, skeletal muscle tissue engineering attempts to grow functional neo­tissue from human stem cells to promote tissue regeneration and support defect closure. Despite intensive research efforts, the goal of stable induction of myogenic differentiation in expanded human stem cells by using clinically feasible stimuli, has not yet been reached to a sufficient extent. Therefore, the present study investigated the differentiation potential of static magnetic fields (SMFs), using co­cultures of human satellite cells and human mesenchymal stem cells (MSCs). It has previously been demonstrated that SMFs may act as a promising myogenic stimulus. Tests were performed on co­cultures with and without SMF exposure, using growth medium [high growth factor concentrations (GM)] and differentiation medium [low growth factors concentrations (DM)]. AlamarBlue® assay­based cell proliferation analysis revealed no significant difference between co­cultures with, vs. without SMF stimulation, regardless of growth factor concentrations in the cell culture medium. To determine the degree of differentiation in co­cultures under stimulation with SMFs, semi­quantitative gene expression measurements of the following marker genes were performed: Desmin, myogenic factor 5, myogenic differentiation antigen 1, myogenin, adult myosin heavy chain 1 and skeletal muscle α1 actin. In neither GM nor DM was a steady, significant increase in marker gene expression detected. Verifying the gene expression findings, immunohistochemical antibody staining against differentiation markers revealed that SMF exposure did not enhance myogenic maturation. Therefore, SMF treatment of human satellite cell/MSC co­cultures did not result in the desired increase in myogenic differentiation. Further studies are required to identify a suitable stimulus for skeletal muscle tissue engineering.