The effect of high-dose pyridoxine (PN) on activity of 5-fluorouracil (FUra) and folinic acid (FA)-containing regimens was studied in 50 patients including 14 with digestive tract, and 36 with breast carcinomas (BC) in advanced stages with poor prognostic characteristics. Patients with colorectal, and pancreas adenocarcinoma received oxaliplatin, irinotecan, FUra, FA (Folfirinox), and patients with squamous cell carcinoma of the esophagus had paclitaxel, carboplatin, FUra, FA (TCbF). Patients with BC received AVCF (doxorubicin, vinorelbine, cyclophosphamide, FUra, FA) followed by TCbF or TCbF only, and patients who overexpressed HER2 received TCbF plus trastuzumab and pertuzumab.
View Article and Find Full Text PDFPurpose: This manuscript reports on the occurrence of early and frequent erythrocytosis in advanced hepatocellular carcinoma (HCC) patients treated with lenvatinib.
Methods: A cohort of 23 patients with advanced HCC, treated with this antiangiogenic drug for at least one month, was retrospectively analyzed.
Results: These patients (82.
High concentration pyridoxal 5'-phosphate, the cofactor of vitamin B6, potentiates cytotoxicity in cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA). We studied the effect of high-dose pyridoxine on antitumor activity of regimens comprising FUra and FA in 27 advanced breast carcinoma patients. Of 18 previously untreated patients, 12 had tumors that did not overexpress HER2 (Group I), and 6 that overexpressed HER2 (Group II).
View Article and Find Full Text PDFSupplementation of cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA) with high concentration pyridoxal 5'-phosphate, the cofactor of vitamin B6, potentiates the cytotoxicity of FUra in a synergistic interaction mode. We report a pilot study in 13 patients with previously untreated advanced carcinoma of the digestive tract to assess the impact of high-dose pyridoxine (PN) on the antitumor activity of regimens comprising FUra and FA. Five patients had colorectal adenocarcinoma (CRC); 5 had pancreas adenocarcinoma (PC); and 3 had squamous cell carcinoma of the esophagus (EC).
View Article and Find Full Text PDFMethionine deprivation induces growth arrest and death of cancer cells. To eliminate l-methionine we produced, purified, and characterized the recombinant pyridoxal 5'-phosphate (PLP)-dependent l-methionine -lyase (MGL)- BL929 from the cheese-ripening Transformation of an strain with the gene from optimized for expression led to production of the MGL-BL929. Elimination of l-methionine and cytotoxicity in vitro were assessed, and methylation-sensitive epigenetics was explored for changes resulting from exposure of cancer cells to the enzyme.
View Article and Find Full Text PDFThe current study originates from the assumption that, in tumors, levels of naturally occurring pyridoxal 5'-phosphate (PLP) are too small to allow conversion of tetra hydro pteroylglutamate (HPteGlu) into methylene tetra hydro pteroylglutamate (CH-HPteGlu) in amounts required to improve inhibition of thymidylate synthase by 5-fluorouracil (FUra) through ternary complex stabilization. The hypothesis relates to the low affinity for cofactor of the PLP-dependent serine hydroxymethyl transferase (SHMT), the enzyme that catalyzes formation of CH-HPteGlu by transfer of the C of serine to HPteGlu. Intracellular concentrations of PLP are smaller than the dissociation constant of SHMT for cofactor, which suggests that enzyme activity should be sensitive to PLP level changes.
View Article and Find Full Text PDFClear cell adenocarcinoma of the cervix is a rare tumor of the lower genital tract. It has been described in young women with a history of intra uterine exposure to diethylstilbestrol. This tumor is characterized by a greater tendency for late recurrences.
View Article and Find Full Text PDFJ Clin Oncol
December 2005
Methionine depletion in the human cell line CCRF-CEM through the action of recombinant methioninase (rMETase), a methionine-cleaving enzyme, was previously demonstrated to produce a strong cytotoxic synergistic effect with fluorouracil (FUra) throughout a broad range of concentrations of FUra and rMETase, including subcytotoxic levels of rMETase. Potentiation was associated with a decrease in free thymidylate synthase from preexisting levels. To further investigate the action of rMETase on CCRF-CEM cells, in the present study we explored the effects of rMETase as a single agent on DNA methylation levels and DNA synthesis, which may be changed as a result of deprivation of methionine.
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