ABSTRACT
Identification of unique features of cancer cells is important for defining specific and efficient therapeutic targets. Mutant p53 is present in nearly half of all cancer cases, forming a promising target for pharmacological reactivation. In addition to being defective for the tumor-suppressor function, mutant p53 contributes to malignancy by blocking a p53 family member p73. Here, we describe a small-molecule RETRA that activates a set of p53-regulated genes and specifically suppresses mutant p53-bearing tumor cells in vitro and in mouse xenografts. Although the effect is strictly limited to the cells expressing mutant p53, it is abrogated by inhibition with RNAi to p73. Treatment of mutant p53-expressing cancer cells with RETRA results in a substantial increase in the expression level of p73, and a release of p73 from the blocking complex with mutant p53, which produces tumor-suppressor effects similar to the functional reactivation of p53. RETRA is active against tumor cells expressing a variety of p53 mutants and does not affect normal cells. The results validate the mutant p53-p73 complex as a promising and highly specific potential target for cancer therapy.
Subject(s)
Antineoplastic Agents/pharmacology , Catechols/pharmacology , DNA-Binding Proteins/metabolism , Mutant Proteins/metabolism , Neoplasms/pathology , Nuclear Proteins/metabolism , Small Molecule Libraries/pharmacology , Thiazoles/pharmacology , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Antineoplastic Agents/chemistry , Catechols/chemistry , Cell Line, Tumor , DNA-Binding Proteins/genetics , Drug Screening Assays, Antitumor , Gene Expression Regulation, Neoplastic/drug effects , Genes, Reporter , Humans , Mice , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Nuclear Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Small Molecule Libraries/chemistry , Thiazoles/chemistry , Transcription, Genetic/drug effects , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Proteins/geneticsABSTRACT
A 147-bp cDNA fragment was isolated from human lymphocytes activated with concanavalin A using the method of direct selection. A complete copy of the selected gene having total homology with the mitochondrial ribosomal gene MRPL37 was obtained by the RACE (rapid amplification of cDNA ends) technique. The MRPL37 gene was localized on human chromosome 1 using a DNA panel composed of somatic cellular human-hamster hybrids. The Northern blotting and RT-PCR (reverse transcription-polymerase chain reaction) demonstrated that the RNA of the human MRPL37 gene is widely represented in the lymphoma populations of Raji B cells and MT4 T cells, as well as in pancreas, liver, and lung embryonic fibroblasts WI-38 and LEH. The highest expression level of the MRPL37 mouse homologue was found in the cells of skeletal muscles, the heart, and organs of reproductive system: the uterus, ovaries, and testicles. A comparative analysis of the MRPL37 amino acid sequence with those of proteins represented in the Fasta33 and GenBank databases showed a homologous region in MRPL37 and PDCD9 (programmed cell death 9, MPRS30) proteins. The chicken homologue of PDCD9 is interesting because its overexpression causes apoptosis of the mouse fibroblasts C3H10T1/2. The existence of a common domain indicates possible similar functional peculiarities of the PDCD9 and MRPL37 genes and may imply the MRPL37 involvement in the process of apoptosis. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 5; see also http: // www.maik.ru.
Subject(s)
Gene Expression Regulation , Ribosomal Proteins/genetics , Amino Acid Sequence , Animals , Apoptosis/genetics , Base Sequence , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cells, Cultured , Chickens/genetics , Chromosome Mapping , Chromosomes, Human, Pair 1 , Cloning, Molecular , DNA, Complementary , Female , Fibroblasts/pathology , Fibroblasts/physiology , Humans , Lymphoma, B-Cell/genetics , Lymphoma, B-Cell/pathology , Male , Mice , Mitochondrial Proteins , Molecular Sequence Data , Ribosomal Proteins/metabolism , Sequence Homology, Amino Acid , T-Lymphocytes/pathology , T-Lymphocytes/physiology , Tumor Suppressor Protein p53/geneticsABSTRACT
Modified proteins were determined by isoelectric focusing in borate-polyol system with subsequent colorimetry (micromethod) and electrophoresis of blood serum on paper with subsequent TCA-ethanol treatment. Increased levels of glycated hemoglobin and modified albumin and changed light absorbance of glycated albumin were detected. The levels of glycated hemoglobin assessed by the micromethod and colorimetry without calibration did not correlate.
