Stimulation of fibroblast proliferation by neokyotorphin requires Ca influx and activation of PKA, CaMK II and MAPK/ERK.

Neokyotorphin [TSKYR, hemoglobin alpha-chain fragment (137-141)] has previously been shown to enhance fibroblast proliferation, its effect depending on cell density and serum level. Here we show the dependence of the effect of neokyotorphin on cell type and its correlation with the effect of protein kinase A (PKA) activator 8-Br-cAMP, but not the PKC activator 4beta-phorbol 12-myristate, 13-acetate (PMA). In L929 fibroblasts, the proliferative effect of neokyotorphin was suppressed by the Ca2+ L-type channel inhibitors verapamil or nifedipine, the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, kinase inhibitors H-89 (PKA), KN-62 (Ca2+/calmodulin-dependent kinase II) and PD98059 (mitogen-activated protein kinase).

Antitumor effect of valorphin in vitro and in vivo: combined action with cytostatic drugs.

The action of the cytostatic drugs (epirubicin and vincristine) in combination with the endogenous antiproliferative beta-hemoglobin fragment (33-39), valorphin, was studied in tumor (L929 and A549) cell cultures, primary culture of murine bone marrow cells and in murine model of breast carcinoma in vivo. Simultaneous application of 1 microM valorphin and 1 microM epirubicin, in vitro, did not result in an additive suppressive effect on cell culture growth. Additive effects were achieved with alternating applications of the peptide and the drugs, namely, 0.

What to synthesize? From Emil Fischer to peptidomics.

The driving forces, incentives and strategic targets of peptide synthesis have undergone considerable evolution during the centenary following the pioneer work of Emil Fischer. In those days peptide synthesis was considered as a way of confirming the polypeptide theory of protein structure. The scientific community also expected (naively) that the synthesis would eventually lead to the creation of artificial living organisms.

Proliferative activity of neokyotorphin-related hemoglobin fragments in cell cultures.

alpha-Hemoglobin fragments alpha-(133-141), alpha-(134-141), alpha-(135-141), alpha-(137-141), alpha-(134-140), alpha-(133-138), alpha-(134-140) and alpha-(137-138) stimulate L929 tumor cell proliferation, alpha-(134-141) being the most active. alpha-(134-141) stimulates proliferation of M3 melanoma cells, murine embryonic fibroblasts, primary cultures of red bone marrow and spleen cells. In L929 cells the effect of alpha-(134-141) is cell density independent; in M3 cells alpha-(137-141) and alpha-(134-141) are most active at density 10,000 cells/well (96 well plate) independently on FBS content.