OBJECTIVETo investigate the time course of let-7a microRNA expression in the cell cycle of HeLa cells.

METHODSHeLa cells were synchronized in G(1), S and G(2)/M phases using double-thymidine block, and the cell cycle phases were defined by flow cytometry. Real-time quantitative RT-PCR was used to examine the expression of let-7a in HeLa cells in different cell cycle phases.

RESULTSThe synchronization rates of G(1), S and G(2)/M phases were 84.81%, 83.65% and 77.69%, respectively. Let-7a was constitutively expressed throughout the cell cycle in HeLa cells, but the expression levels in G(1) and S phases were lower than those in G(2)/M phase.

CONCLUSIONSCell cycle can significantly influence the expression level of let-7a, which may provide new clues to the understanding of the cell cycle control mechanisms.

Cell Cycle ; genetics ; Gene Expression Regulation, Neoplastic ; physiology ; HeLa Cells ; Humans ; MicroRNAs ; genetics ; metabolism

The microRNAs (miRNAs) are an evolutionarily conserved class of 22 nucleotide (19 - 25 nt) non-coding RNAs. The miRNAs are partially complementary to 3' untranslated region of target mRNA, resulting in the repression of gene expression at post-transcriptional level. The miRNAs have been associated with diverse biological processes. This review summarizes recent progress of research on the characteristics and function of miRNAs, and the role of miRNAs in hematological malignancy development.
Gene Expression Regulation, Neoplastic ; genetics ; Hematologic Neoplasms ; genetics ; metabolism ; Humans ; MicroRNAs ; genetics ; physiology

OBJECTIVEThis article aims to review recent studies on the biological characteristics of long non-coding RNAs (lncRNAs), transcription regulation by lncRNAs, and the results of recent studies on the mechanism of action of lncRNAs in tumor development.

DATA SOURCESThe data cited in this review were mainly obtained from the articles listed in PubMed and HighWire that were published from January 2002 to June 2010. The search terms were "long non-coding RNA", "gene regulation", and "tumor".

STUDY SELECTIONThe mechanism of lncRNAs in gene expression regulation, and tumors concerned with lncRNAs and the role of lncRNAs in oncogenesis.

RESULTSlncRNAs play an important role in transcription regulation by controlling chromatin remodeling, transcriptional control, and post-transcriptional controlling. lncRNAs are involved in many kinds of tumors and play key roles as both suppressing and promoting factors.

CONCLUSIONlncRNAs could perfectly regulate the balance of gene expression system and play important roles in oncogenic cellular transformation.

Animals ; Cell Transformation, Neoplastic ; genetics ; Gene Expression Regulation ; genetics ; physiology ; Humans ; Neoplasms ; genetics ; RNA, Untranslated ; genetics

Autophagy is a conserved catabolic process characterized by degradation and recycling of cytosolic components or organelles through a lysosome-dependent pathway. It has a complex and close relationship to drug resistance in breast cancer. MicroRNAs (miRNAs) are small noncoding molecules that can influence numerous cellular processes including autophagy, through the posttranscriptional regulation of gene expression. Autophagy is regulated by many proteins and pathways, some of which in turn have been found to be regulated by miRNAs. These miRNAs may affect the drug resistance of breast cancer. Drug resistance is the main cause of distant recurrence, metastasis and death in breast cancer patients. In this review, we summarize the causative relationship between autophagy and drug resistance of breast cancer. The roles of autophagy-related proteins and pathways and their associated miRNAs in drug resistance of breast cancer are also discussed.
Autophagy/physiology* ; Breast Neoplasms/pathology* ; Drug Resistance, Neoplasm ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs/physiology* ; Signal Transduction/physiology*

Breast Neoplasms ; etiology ; genetics ; therapy ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; physiology ; Neoplastic Stem Cells ; metabolism

Apoptosis ; Cell Proliferation ; Cell Transformation, Neoplastic ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; classification ; genetics ; metabolism ; physiology ; Neoplasms ; genetics ; metabolism ; pathology ; Signal Transduction

Prostate cancer is one of the common cancers in old men. Androgen ablation is a major option for the treatment of the metastatic diseases. However, most of the cancers progress to a more aggressive stage, so-called androgen-independent (or hormone refractory) relapse beyond any cure. The androgen receptor (AR) is an important factor in regulating the differentiation and proliferation of prostate epithelial cells, and also plays a critical role in cellular survival. Studies have demonstrated that aberrant activation of the AR is a major determinant in prostate cancer progression. We have provide a brief summary of AR-mediated cellular survival and an introduction to the advances of RNA interference techniques in silencing AR expression as a novel therapy for prostate cancer.
Apoptosis ; physiology ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Prostatic Neoplasms ; genetics ; pathology ; physiopathology ; RNA Interference ; Receptors, Androgen ; genetics ; physiology

OBJECTIVETo review the recent studies about the role of indoleamine 2,3-dioxygenase (IDO) in tumor induced tolerance.

DATA SOURCESPublished articles (1978 - 2009) on IDO and tumor induced tolerance were selected from Medline.

STUDY SELECTIONArticles selected were relevant to development of IDO in tumor induced tolerance. Of all originally identified articles, 50 specially addressed the stated purpose.

RESULTSRecent work has revealed IDO at high levels in tumors and in tumor-draining lymph nodes and a close relationship between IDO activity and the regulatory T cells.

CONCLUSIONUp-regulation of IDO is proven to be a mechanism of acquired tolerance in tumors, in which the closely coupled positive feedback system between IDO and regulatory T cells may be considered to play an important role.

Animals ; Gene Expression Regulation, Neoplastic ; physiology ; Humans ; Immune Tolerance ; physiology ; Indoleamine-Pyrrole 2,3,-Dioxygenase ; metabolism ; Neoplasms ; enzymology ; immunology

Triple-negative breast cancer (TNBC) is currently the most malignant subtype of breast cancer without effective targeted therapies, which makes its pathogenesis an important target for research. A growing number of studies have shown that non-coding RNA (ncRNA), including microRNA (miRNA) and long non-coding RNA (lncRNA), plays a significant role in tumorigenesis. This review summarizes the roles of miRNA and lncRNA in the progression, diagnosis, and neoadjuvant chemotherapy of TNBC. Aberrantly expressed miRNA and lncRNA are listed according to their roles. Further, it describes the multiple mechanisms that lncRNA shows for regulating gene expression in the nucleus and cytoplasm, and more importantly, describes lncRNA-regulated TNBC progression through complete combining with miRNA at the post-transcriptional level. Focusing on miRNA and lncRNA associated with TNBC can provide new insights for early diagnosis and treatment-they can be targeted in the future as a novel anticancer target of TNBC.
Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs/physiology* ; Neoadjuvant Therapy ; RNA, Long Noncoding/physiology* ; Triple Negative Breast Neoplasms/pathology*

Wnt3a, one of Wnt family members, plays key roles in regulating pleiotropic cellular functions, including self-renewal, proliferation, differentiation, and motility. Accumulating evidence has suggested that Wnt3a promotes or suppresses tumor progression via the canonical Wnt signaling pathway depending on cancer type. In addition, the roles of Wnt3a signaling can be inhibited by multiple proteins or chemicals. Herein, we summarize the latest findings on Wnt3a as an important therapeutic target in cancer.
Cell Division ; physiology ; Gene Expression Regulation, Neoplastic ; physiology ; Humans ; Neoplasm Proteins ; metabolism ; physiology ; Neoplasms ; genetics ; metabolism ; pathology ; Tumor Cells, Cultured ; Wnt Signaling Pathway ; physiology ; Wnt3A Protein ; metabolism ; physiology