Simultaneous regulation of polyamine metabolism and miR-34a expression by DSS-BEN/miR-34a not only enhanced cancer cell killing in cultured human colon cancer cells, but also improved antitumor activity in vivo.
We analyzed data on human colorectal carcinomas from the Cancer Genome Atlas collection to determine whether expression of PPP1R11 was affected by altered level or activity of p53, markers of epithelial-to-mesenchymal transition (EMT), or MIR34A or was associated with metastasis.
Although miR-34A deregulation may be an important driver in cancer, the endogenous role of this microRNA in cellular homeostasis is not well characterized.
MicroRNA-34a induces a senescence-like change via the down-regulation of SIRT1 and up-regulation of p53 protein in human esophageal squamous cancer cells with a wild-type p53 gene background.
Particularly miR-34a has been revealed to be a direct transcriptional target of p53 which is frequently mutated in epithelial ovarian carcinomas especially in high grade serous cancer.
Furthermore, we revealed that RIG-I and miR-34a enhanced apoptosis, delayed the G1/S/G2 transition of the cell cycle, and inhibited the epithelial-mesenchymal transition process to modulate malignancies in cervical cancer cells.
Increasing studies demonstrate that reduced expression of miR-34a is involved in the initiation and progression of cancers, and it has been characterized as a tumor suppressor in various types of cancers.
Esophageal squamous cell carcinoma (ESCC), one of the most common gastrointestinal tumors, is known for its high mortality rate. microRNAs (miRNAs) have been reported to play important regulatory roles in cancer metastasis and progression. miR-34a has been demonstrated to be associated with the development of and metastasis in certain types of cancer via various target genes, but its function and targets in ESCC are unknown.
These data underline that the expression of miR-34a and down-modulation of TGFbeta signaling emerge as pivotal events to drive CD99-mediated reversal of malignancy and activation of differentiation in OS cells.
This article introduces the roles of miR-34a in cancer development, metastasis as well as its mechanism of actions on target genes and the functional outcomes of its actions on radio-sensitivity.
In this review, we provide a complex overview of miR-34a, including regulating its expression, its known functions in cancer and future challenges as a potential therapeutic target in human cancers.
Moreover, delivery or re-expression of miR-34 leads to notable repression of tumor growth and metastasis in cancer mouse models, and may therefore represent an efficient strategy for future cancer therapeutics.
In fact, deregulation and abnormal expression of these molecules is associated with human pathologies including cancer and several have already emerged as potential prognostic biomarkers in different neoplasias. miR-34a is directly regulated by p53 and acts as tumor suppressor while miR-125b plays a significant role in immune response and apoptosis.
This intriguing hypothesis is supported by several observations: i) in endothelial cells undergoing replicative senescence (HUVECs), a well-established model of cell senescence, miR-146a, miR-34a, and miR-181a are over-expressed whereas their target Bcl-2 is down-regulated; ii) IPA of the miR-146a, miR-34a and miR-181a network shows that they are closely linked to each other, to Bcl-2 and to mitochondria; and iii) miR-146a, miR-34a, and miR-181a are involved in important cell functions (growth, proliferation, death, survival, maintenance) and age-related diseases (cancer, skeletal and muscle disorders, neurological, cardiovascular and metabolic diseases).
MiR-34a, a direct target of p53, has been shown to target several molecules associated with the cell cycle and cell survival pathways, and its dysregulation is implicated in cancer drug resistance or sensitivity in several human cancers.