MicroRNAs in lung cancer

Roles of the Hippo pathway in lung development and tumorigenesis

Lung cancer is the most commonly diagnosed cancer and accounts for one fifth of all cancer deaths worldwide. Although significant progress has been made toward our understanding of the causes of lung cancer, the 5-year survival is still lower than 15%. Therefore, there is an urgent need for novel lung cancer biomarkers and drug targets. The Hippo signaling pathway is an emerging signaling pathway that regulates various biological processes. Recently, increasing evidence suggests that the Hippo pathway may play important roles in not only lung development but also lung tumorigenesis. In this review article, we will summarize the most recent advances and predict future directions on this new cancer research field.

PI3K/Akt signaling in osteosarcoma

Osteosarcoma (OS) is the most common nonhematologic bone malignancy in children and adolescents. Despite the advances of adjuvant chemotherapy and significant improvement of survival, the prognosis remains generally poor. As such, the search for more effective anti-OS agents is urgent. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is thought to be one of the most important oncogenic pathways in human cancer. An increasing body of evidence has shown that this pathway is frequently hyperactivated in OS and contributes to disease initiation and development, including tumorigenesis, proliferation, invasion, cell cycle progression, inhibition of apoptosis, angiogenesis, metastasis and chemoresistance. Inhibition of this pathway through small molecule compounds represents an attractive potential therapeutic approach for OS. The aim of this review is to summarize the roles of the PI3K/Akt pathway in the development and progression of OS, and to highlight the therapeutic potential of targeting this signaling pathway. Knowledge obtained from the application of these compounds will help in further understanding the pathogenesis of OS and designing subsequent treatment strategies.

Introduction to microRNAs: Biogenesis, Action, Relevance of Tissue microRNAs in Disease Pathogenesis, Diagnosis and Therapy-The Concept of Circulating microRNAs

MicroRNAs as the endogenous mediators of RNA interference have principal roles in gene expression regulation. Since their discovery in the early 1990s, their number has steadily grown to approximately 2500 known microRNAs at present in humans. MicroRNAs encoded by distinct genes regulate the expression of about 30-60 % of human protein coding genes by targeting their messenger RNAs (mRNAs) and induce mostly posttranscriptional inhibition, or in some cases enhancement. MicroRNAs, as fine regulators of the gene expression, have important roles in development, the physiological functioning of the organism, e.g. organogenesis, immune functioning, vascular system, etc. The deregulation of microRNA expression has been observed in many disorders, such as in carcinogenesis. Given their tissue specificity and stability, and specific disease-related alterations, tissue microRNAs can be exploited as excellent biomarkers in the diagnosis. Moreover, microRNAs might also be envisaged as novel therapeutic targets. Beside tissue microRNAs, novel data show that microRNAs are also present in body fluids that could further extend their diagnostic utility as minimally invasive biomarkers of various diseases, but also raises intriguing questions regarding their biological relevance. In this introductory chapter, we summarise the most relevant features of microRNAs including their biogenesis, action, the biological, pathological, diagnostic and potential therapeutical relevance of tissue microRNAs.