RESUMEN
Using real-time RT-PCR in combination with bioinformatics, we have shown for the first time that the treatment of HCT-116 and HT-29 colon cancer cells with two anti-cancer agents (doxycycline or 3,3'-diindolylmethane) results in profound changes in the intracellular content of several lncRNAs (by up to 100 times). Since many of these RNAs are secreted by tumors into the bloodstream, the obtained results provide a basis for developing more sensitive protocols for serological monitoring of tumor relapse and metastasis, as well as for search of new anti-cancer drugs.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias del Colon/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , ARN Largo no Codificante/biosíntesis , ARN Neoplásico/biosíntesis , Línea Celular Tumoral , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Humanos , ARN Largo no Codificante/genética , ARN Neoplásico/genéticaRESUMEN
Retinoids are signaling molecules that control a wide variety of cellular processes and possess antitumor activity. This work presents a comprehensive description of changes in the expression of 23 genes that regulate retinoid metabolism and signaling in non-small-cell lung cancer tumors compared to adjacent normal tissues obtained using RT-PCR. Even at early stages of malignant transformation, a significant decrease in ADH1B, ADH3, RDHL, and RALDH1 mRNA levels was observed in 82, 79, 73, and 64% of tumor specimens, respectively, and a considerable increase in AKR1B10 mRNA content was observed in 80% of tumors. Dramatic changes in the levels of these mRNAs can impair the synthesis of all-trans retinoic acid, a key natural regulatory retinoid. Apart from that, it was found that mRNA levels of nuclear retinoid receptor genes RXRγ, RARα, RXRα, and gene RDH11 were significantly decreased in 80, 67, 57, and 66% of tumor specimens, respectively. Thus, neoplastic transformation of lung tissue cells is accompanied with deregulated expression of key genes of retinoid metabolism and function.
Asunto(s)
3-Hidroxiesteroide Deshidrogenasas/biosíntesis , Alcohol Deshidrogenasa/biosíntesis , Aldehído Deshidrogenasa/biosíntesis , Aldehído Reductasa/biosíntesis , Carcinoma de Pulmón de Células no Pequeñas/genética , 3-Hidroxiesteroide Deshidrogenasas/genética , Alcohol Deshidrogenasa/genética , Aldehído Deshidrogenasa/genética , Familia de Aldehído Deshidrogenasa 1 , Aldehído Reductasa/genética , Aldo-Ceto Reductasas , Carcinoma de Pulmón de Células no Pequeñas/patología , Transformación Celular Neoplásica/genética , Regulación Neoplásica de la Expresión Génica , Humanos , ARN Mensajero/biosíntesis , Receptores de Ácido Retinoico/biosíntesis , Receptores de Ácido Retinoico/genética , Retinal-Deshidrogenasa , Receptor alfa de Ácido Retinoico , Retinoides/genética , Retinoides/metabolismo , Transducción de Señal/genética , Tretinoina/metabolismoRESUMEN
Centromeric region of human chromosome 21 comprises two long alphoid DNA arrays: the well homogenized and CENP-B box-rich alpha21-I and the alpha21-II, containing a set of less homogenized and CENP-B box-poor subfamilies located closer to the short arm of the chromosome. Continuous alphoid fragment of 100 monomers bordering the non-satellite sequences in human chromosome 21 was mapped to the pericentromeric short arm region by fluorescence in situ hybridization (alpha21-II locus). The alphoid sequence contained several rearrangements including five large deletions within monomers and insertions of three truncated L1 elements. No binding sites for centromeric protein CENP-B were found. We analyzed sequences with alphoid/non-alphoid junctions selectively screened from current databases and revealed various rearrangements disrupting the regular tandem alphoid structure, namely, deletions, duplications, inversions, expansions of short oligonucleotide motifs and insertions of different dispersed elements. The detailed analysis of more than 1100 alphoid monomers from junction regions showed that the vast majority of structural alterations and joinings with non-alphoid DNAs occur in alpha satellite families lacking CENP-B boxes. Most analyzed events were found in sequences located toward the edges of the centromeric alphoid arrays. Different dispersed elements were inserted into alphoid DNA at kinkable dinucleotides (TG, CA or TA) situated between pyrimidine/purine tracks. DNA rearrangements resulting from different processes such as recombination and replication occur at kinkable DNA sites alike insertions but irrespectively of the occurrence of pyrimidine/purine tracks. It seems that kinkable dinucleotides TG, CA and TA are part of recognition signals for many proteins involved in recombination, replication, and insertional events. Alphoid DNA is a good model for studying these processes.
Asunto(s)
Autoantígenos , Centrómero/genética , Cromosomas Humanos Par 21/genética , ADN Satélite/genética , Proteínas de Unión al ADN , Mutagénesis Insercional/genética , Conformación de Ácido Nucleico , Recombinación Genética/genética , Elementos Alu/genética , Secuencia de Bases , Sitios de Unión , Centrómero/química , Centrómero/metabolismo , Proteína B del Centrómero , Proteínas Cromosómicas no Histona/metabolismo , Deleción Cromosómica , Inversión Cromosómica , Cromosomas Humanos Par 21/química , Cromosomas Humanos Par 21/metabolismo , Biología Computacional , Intercambio Genético/genética , Replicación del ADN/genética , ADN Satélite/química , ADN Satélite/metabolismo , Bases de Datos como Asunto , Repeticiones de Dinucleótido/genética , Humanos , Hibridación Fluorescente in Situ , Linfocitos , Mutación/genética , Reacción en Cadena de la PolimerasaRESUMEN
A structural gene encoding bovine (b) tryptophanyl-tRNA synthetase (WRS) has recently been cloned and sequenced [Garret et al., Biochemistry 30 (1991) 7809-7817]. Using part of this sequence as a hybridisation probe we have cloned and sequenced a structural gene encoding human polypeptide highly homologous with two mammalian proteins, bWRS [Garret et al., Biochemistry 30 (1991) 7809-7817; EMBL accession No. X52113] and rabbit peptide chain release factor [Lee et al., Proc. Natl. Acad. Sci. USA 87 (1990) 3508-3512]. Identification of the sequence encoding a human WRS is based on (i) the presence of 'HIGH' and 'KMSKS' structural motifs typical for class-I aminoacyl-tRNA synthetases [Eriani et al., Nature 347 (1990) 203-206]; (ii) coincidence of the number of SH groups per subunit estimated experimentally [Muench et al., Science 187 (1975) 1089-1091] and deduced from the cDNA sequence (six in both cases); (iii) close resemblance of two WRS polypeptides sequenced earlier [Muench et al., Science 187 (1975) 1089-1091] and the predicted structure in two different regions.