Addition of tumor-promoting phorbol diesters to [32P]phosphate-labeled A431 human epidermoid carcinoma cells caused an increase in the phosphorylation state of the transferrin receptor. The A431 cell transferrin receptor was also found to be a substrate for protein kinase C in vitro. Tryptic phosphopeptide mapping of the transferrin receptor resolved the same two phosphopeptides (X and Y) after...

We found that the convergently epidermal growth factor (EGF)-induced signal and the collagen-induced signal activate mitogen-activated protein kinase (MAPK), which induces migration. We examined the signaling mechanisms of EGF-induced cell migration on collagen using the A431 carcinoma cell. EGF (10 ng/ml) induced migration on collagen, but inhibited proliferation. Using a MAPK cascade inhibito...

Vasoactive intestinal peptide (VIP) is a 28-amino acid peptide with a wide range of biological activities. Recent data suggest that functional VIP receptors are expressed on various tumor cells. Somatostatin (SST) and its long-acting analogue octreotide (OCT) are potent inhibitors of tumor cell growth and secretion. In the present study, the interactions between VIP and SST/OCT on primary tumor...

Tyrosine-specific protein kinase activity of the epidermal growth factor (EGF) receptor, pp60v-src and pp110gag-fes was inhibited in vitro by an isoflavone genistein. The inhibition was competitive with respect to ATP and noncompetitive to a phosphate acceptor, histone H2B. By contrast, genistein scarcely inhibited the enzyme activities of serine- and threonine-specific protein kinases such as ...

Lipid-based oil-filled nanoparticles (NPs) with a high concentration of surface-chelated nickel (Ni-NPs) were successfully prepared using a Brij 78-NTA-Ni conjugate synthesized with Brij 78 (Polyoxyethylene (20) stearyl ether) and nitrilotriacetic acid (NTA). The facile incorporation of the Brij 78-NTA-Ni conjugate into the NP formulation allowed up to 90% Ni incorporation, which was a signific...

BACKGROUND Telomerase is a ribonucleoprotein enzyme which is involved in the maintenance of chromosome ends. Telomerase activity is frequently associated with malignant phenotypes, and it can be considered a ubiquitous tumor marker. In this study we describe an approach for developing in vitro chemosensitivity assays based on the assessment of telomerase activity in squamous cell carcinoma to t...

The detection of autoantibodies to epidermal or basement membrane zone proteins by immunoblot (IB) is useful for the diagnosis and the classification of autoimmune bullous diseases (AIBD). IB using human skin extracts is actually the reference method but A431 cell line is proposed as easier alternate antigen source. We explored the performances of “A431 IB” in comparison with the reference tech...

HAX-1 is an anti-apoptotic factor and overexpressed in many types of cancers. However, the functional role of HAX-1 in human cutaneous squamous cell carcinoma (cSCC) remains unclear. Our aim was to investigate the expression of HAX-1 in cSCC and its relationship with the development of cSCC. HAX-1 expression in cSCC tissues and in-vitro cell models were evaluated by real-time quantitative PCR (...

UNLABELLED The present work was AIMED on the study of human beta-defensin 3 (hBD-3) gene expression in A431 cell line and human vulval tumors. MATERIALS AND METHODS Twenty surgical specimens of both malignant and conventionally normal human vulval tissues have been analyzed for the presence of hBD-3 mRNA by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). In vitro e...

Aquaporin 3 (AQP3) and phospholipase D2 (PLD2) are abnormally expressed and/or localized in squamous cell carcinoma (SCC). AQP3 transports glycerol to PLD2 for the synthesis of lipid second messenger, which can mediate the effect of the AQP3/PLD2 signaling module in the regulation of keratinocyte proliferation and differentiation. However, the role of the AQP3/PLD2 signaling module in the patho...