title: A role for the clock gene per1 in prostate cancer.
abstract: Circadian rhythms regulate diverse physiologic processes, including homeostatic functions of steroid hormones and their receptors. Perturbations of these rhythms are associated with pathogenic conditions, such as depression, diabetes, and cancer. Androgens play an important role in both normal development and carcinogenesis of the prostate. In the present study, we investigated a potential role for the core clock factor Per1 in the pathogenesis of prostate cancer. Serum-shocked synchronized prostate cancer cells displayed disrupted circadian rhythms compared with the normal prostate tissue. Using Oncomine to perform a meta-analysis of microarray expression studies, we found that Per1 is down-regulated in human prostate cancer samples compared with normal prostates. Reporter assays showed that Per1 inhibited transactivation of the androgen receptor (AR) both in 293T cells overexpressing the AR and in the prostate cancer cell line LNCaP. Forced expression of Per1 in LNCaP cells diminished the expression of known androgen-sensitive genes following stimulation with dihydrotestosterone. We showed that Per1 physically interacted with AR; in addition, we found that Per1 itself is regulated by androgens in prostate cancer cells. Overexpression of Per1 in prostate cancer cells resulted in significant growth inhibition and apoptosis. Our results support the emerging role of circadian genes as key players in malignant transformation. Further elucidating the connections between clock genes and the AR pathway could benefit the development of new therapeutic strategies for prostate cancer as well as provide insights into chronotherapy as a way to optimize current therapies.
authors.affiliation: Cedars-Sinai Medical Center, Division of Hematology/Oncology, University of California at Los Angeles School of Medicine, Los Angeles, California 90048, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cao
authors.forename: Sigal
authors.initials: S
authors.lastname: Gery
authors.forename: Azadeh
authors.initials: A
authors.lastname: Dashti
authors.forename: Dong
authors.initials: D
authors.lastname: Yin
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Jiang
authors.initials: J
authors.lastname: Gu
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
mesh_terms: D000818:Animals; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D041681:NIH 3T3 Cells; D056950:Period Circadian Proteins / Q000235:genetics* / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism; D011944:Receptors, Androgen / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D056950:Period Circadian Proteins; D011944:Receptors, Androgen