Application of the trimethylsilyl trifluoromethanesulfonate deprotecting procedure for the synthesis of porcine peptide YY (PYY)

A 36-residue peptide amide corresponding to the entire amino acid sequence of porcine peptide YY (PYY) was synthesized by assembling eight peptide fragments of established purity, followed by hard acid deprotection with 1m trimethylsilyl trifluoromethanesulfonate in trifluoroacetic acid. β-Cycloheptylaspartate, Asp(OChp), was employed to minimize the base-catalyzed succinimide formation. When administered to dogs, synthetic PYY was active as natural peptide in its effects on exocrine pancreatic secretion and pancreatic tissue blood flow.     

Granulocyte-colony stimulating factor-induced proliferation of primary adult T-cell leukaemia cells

Granulocyte-colony stimulating factor (G-CSF) is known to induce proliferation and differentiation of granulocyte progenitors, and is widely used to treat neutropenia induced by intensive chemotherapy for malignant lymphoma or adult T-cell leukaemia/lymphoma (ATL). G-CSF is thought not to stimulate malignant lymphoid cells. In the present study we examined the ability of G-CSF to induce in vitro growth of primary ATL cells from 14 patients (nine acute-type, two chronic-type and three lymphoma-type), and we analysed the in vivo counts of ATL cells in patients who received G-CSF for neutropenia. FACS analysis using phycoerythrin-labelled recombinant G-CSF demonstrated that ATL cells from 11/14 patients express some G-CSF receptor (G-CSFR), with a range between 5.4% and 87.3%. Cells expressing G-CSFR also expressed CD4. Reverse polymerase chain reaction (PCR) analysis demonstrated expression of G-CSFR messenger RNA in G-CSFR expressing cells. Leukaemic cells derived from seven (four acute-type, one chronic-type and two lymphoma-type) of the 14 patients proliferated in vitro in response to G-CSF, as measured by [³H]thymidine incorporation; maximum responses were at G-CSF concentrations of 10–100 ng/ml. Nine of 14 patients receiving rG-CSF for neutropenia were analysed retrospectively for ATL cell numbers. Four patients whose primary tumour cells proliferated in response to rG-CSF in vitro showed a significant increase in ATL cell count after administration of rG-CSF ( P  =0.038), whereas five patients whose leukaemic cells did not proliferate in vitro showed no significant increase in ATL cell count. G-CSF can stimulate proliferation of ATL cells which may complicate therapy for this disease.     

Solid-phase synthesis of cionin,a protochordate-derived octapeptide related to the gastrin/cholecystokinin family of peptides,and its mono-tyrosine-sulfate-containing derivatives

Cionin, a protochordate-derived octapeptide amide related to the gastrin/cholecystokinin family of peptides, contains two consecutive tyrosine sulfate residues. In order to gain insight into the role of the respective tyrosine sulfate residue in biological activity, cionin and its derivatives in which one of the two tyrosine sulfate residues was replaced by tyrosine, were prepared by two Fmoc-based solid-phase approaches. In approach ( 1 ) Fmoc-Tyr(SO₃Na)-OH was employed as a building block to assemble the Tyr(SO₃Na)-containing peptide-resin, and a global deprotection cleavage was conducted with 90% aqueous TFA in the presence of m-cresol and 2-methylindole at 4°C. In approach ( 2 ) the Tyr(Msib) [Msib =p-(methylsulfinyl)benzyl] derivative was used for the peptide-chain assembly to achieve sulfation on the selective Tyr residue. Partially protected peptide with the Msib Msz protecting groups [Msz =p-(methylsulfinyl)benzyloxycarbonyl], obtained after peptide-resin cleavage, was treated with DMF-SO₃ complex in the presence of ethanedithiol to achieve the sulfation of free Tyr residue and the reduction of the Msib/Msz groups to TFA-labile Mtb/Mtz groups [Mtb =p-(methyithio)benzyl, Mtz =p-(methylthio)benzyloxycarbonyl]. Final deprotection of the Mtb/ Mtz groups with 90° aqueous TFA in the presence of m-cresol and 2-methylindole gave the desired cionin derivative, which contains the tyrosine sulfate residue at the selective position. Yields obtained with approach ( 2 ) were considerably higher than those obtained with approach ( 1 ). Cionin and mono-Tyr(SO³H)-containing derivatives were assayed on exocrine pancreas in dogs.     

Selective inhibition of NS-398 on prostanoid production in inflamed tissue in rat carrageenan-air-pouch inflammation

Abstract— NS-398 (N-(2-cyclohexyloxy-4-nitrophenyl) methane sulphonamide), a newly synthesized potent non-steroidal antiinflammatory drug (NSAID) has a much lesser degree of toxicity, as compared with presently available NSAIDs. We have investigated the inhibition of prostanoid production in inflammatory exudate, gastric mucosa and renal papillary tissue, following oral administration to carrageenan-air-pouch rats. The ID50 values of NS-398 in the inflammatory exudate, gastric mucosa and renal papillary tissue were 0·18, 62·2 and 261·7 mg kg^?1, respectively. In contrast, indomethacin decreased the PGE₂ concentration in the inflammatory exudate, gastric mucosa and renal papillary tissue, with the same dose range, the ID50 values being 0·23, 0·14 and 0·15 mg kg^?1, respectively. The same tendency was seen for 6-keto-prostaglandin F₁ and thromboxane B₂. Moreover, NS-398 inhibited excess PGE₂ production in inflamed tissue but did not affect physiological production of PGE₂ in non-inflamed tissue. Indomethacin, in both inflamed and non-inflamed tissues, inhibited PGE₂ production to the same degree. These results indicated that NS-398 has some specificity for inflamed tissue, by inhibiting prostanoid synthesis, and this effect may explain the decreased side-effects of this drug.