RESUMEN
Elucidation of mechanisms regulating cell cycle progression is of fundamental importance for cell and cancer biology. Although several genes and signaling pathways are implicated in G1-S regulation, less is known regarding the mechanisms controlling cell cycle progression through G2 and M phases. We report that extracellular signal-regulated kinase 5 (ERK5), a member of the mitogen-activated protein kinases, is activated at G2-M and required for timely mitotic entry. Stimulation of ERK5 activated nuclear factor kappaB (NFkappaB) through ribosomal S6 kinase 2 (RSK2)-mediated phosphorylation and degradation of IkappaB. Furthermore, selective inhibition of NFkappaB at G2-M phases substantially delayed mitotic entry and inhibited transcription of G2-M-specific genes, including cyclin B1, cyclin B2, Plk-1, and cdc25B. Moreover, inhibition of NFkappaB at G2-M diminished mitosis induced by constitutive activation of ERK5, providing a direct link between ERK5, NFkappaB, and regulation of G2-M progression. We conclude that a novel ERK5-NFkappaB signaling pathway plays a key role in regulation of the G2-M progression.
Asunto(s)
Fase G2 , Proteína Quinasa 7 Activada por Mitógenos/metabolismo , Mitosis , FN-kappa B/metabolismo , Línea Celular , Células HeLa , Humanos , Proteínas I-kappa B/metabolismo , Proteínas Quinasas S6 Ribosómicas 90-kDa/metabolismo , Transducción de SeñalRESUMEN
PURPOSE: To evaluate (1) whether there were racial differences in the androgen receptor gene CAG repeat length and in clinical or laboratory attributes of prostate cancer at the time of diagnosis; (2) whether there were differences in race, Gleason score, prostate-specific antigen (PSA) level, and stage at diagnosis by androgen receptor gene CAG repeat length; and (3) whether sociodemographic, clinical, and laboratory based factors might be associated with advanced-stage prostate cancer. To our knowledge, our study is the first to report on CAG repeat lengths in a cohort of prostate cancer patients, which includes large numbers of African-American men. METHODS: CAG repeat lengths on the androgen receptor gene were evaluated for 151 African-American and 168 white veterans with prostate cancer. The chi(2) test, t test, and logistic regression analyses were used to evaluate the associations between CAG repeat lengths and race, stage, histologic grade, and PSA levels at diagnosis. RESULTS: The mean age of the cohort at the time of diagnosis was 68.7 years. At presentation, 42.0% had stage D prostate cancer, 26.5% had Gleason scores of 8 to 10, and 53.0% had PSA levels >/= 10 ng/dL. Mean androgen receptor gene CAG repeat length for white veterans was 21.9 (SD, 3.5) versus 19.8 (SD, 3.2) for African-American veterans (P =.001). Men with shorter CAG repeats were more likely to have stage D prostate cancer (P =.09) but were not more likely to have a higher PSA concentration or Gleason score. CONCLUSION: In this cohort of men with prostate cancer, short CAG repeat length on the androgen receptor gene was associated with African-American race and possibly with higher stage but not with other clinical or pathologic findings.
Asunto(s)
Población Negra/genética , Predisposición Genética a la Enfermedad/genética , Neoplasias de la Próstata/genética , Receptores Androgénicos/genética , Repeticiones de Trinucleótidos/genética , Anciano , Humanos , Modelos Logísticos , Masculino , Estadificación de Neoplasias , Polimorfismo Genético , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/mortalidad , Factores Socioeconómicos , Población Blanca/genéticaRESUMEN
The androgen receptor plays a major role in the development and function of normal and malignant prostate cells. Due to the relationship of the androgen receptor and prostatic growth, it has been proposed that polymorphisms within the androgen receptor may play a role in an individual's susceptibility to developing prostate cancer. An inverse relationship has been established between a highly polymorphic trinucleotide repeat located in the first exon of the androgen receptor and the transactivaton function of the receptor. Serum samples were collected from 131 patients with histologically confirmed adenocarcinoma of the prostate, DNA was isolated, and the polymorphic CAG repeat was amplified by PCR and sequenced. The CAG repeat lengths were then compared with age at diagnosis, age at time of study, baseline log(10) PSA, Gleason score, time from diagnosis to initiation of hormonal therapy, time to progression after androgen ablation, and overall survival time. No correlation was found between CAG length and time to progression or overall survival time, but a significant correlation was found between Gleason score and CAG length suggesting that shorter CAG lengths may predict a higher histological grade of prostate cancer.