The aberrant expression of miR-221 is a hallmark of human cancers, including hepatocellular carcinoma (HCC), and its involvement in drug resistance, together with a proved
efficacy of anti-miR-221 ...molecules, strengthen its role as an attractive target candidate in the oncologic field. The discovery of biomarkers predicting the response to treatments represents a clinical challenge in the personalized treatment era. This study aimed to investigate the possible role of miR-221 as a circulating biomarker in HCC patients undergoing sorafenib treatment as well as to evaluate its contribution to sorafenib resistance in advanced HCC.
A chemically induced HCC rat model and a xenograft mouse model, together with HCC-derived cell lines were employed to analyze miR-221 modulation by Sorafenib treatment. Data from the functional analysis were validated in tissue samples from surgically resected HCCs. The variation of circulating miR-221 levels in relation to Sorafenib treatment were assayed in the animal models and in two independent cohorts of patients with advanced HCC.
MiR-221 over-expression was associated with Sorafenib resistance in two HCC animal models and caspase-3 was identified as its target gene, driving miR-221 anti-apoptotic activity following Sorafenib administration. Lower pre-treatment miR-221 serum levels were found in patients subsequently experiencing response to Sorafenib and an increase of circulating miR-221 at the two months assessment was observed in responder patients.
MiR-221 might represent a candidate biomarker of likelihood of response to Sorafenib in HCC patients to be tested in future studies. Caspase-3 modulation by miR-221 participates to Sorafenib resistance.
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Tumor growth and metastatic spreading are heavily affected by the P2X7 receptor as well as microvesicles and exosomes release into the tumor microenvironment. P2X7 receptor stimulation is known to ...trigger vesicular release from immune and central nervous system cells. However, P2X7 role in microvesicles and exosomes delivery from tumor cells was never analyzed in depth. Here we show that P2X7 is overexpressed in patients affected by metastatic malignant melanoma and that its expression closely correlates with reduced overall survival. Antagonism of melanoma cell-expressed P2X7 receptor inhibited in vitro anchorage-independent growth and migration and in vivo dissemination and lung metastasis formation. P2X7 stimulation triggered the release of miRNA-containing microvesicles and exosomes from melanoma cells, profoundly altering the nature of their miRNA content, as well as their dimensions and quantity. Among the more than 200 miRNAs that we found up-or-down-modulated for each vesicular fraction tested, we identified three miRNAs, miR-495-3p, miR-376c-3p, and miR-6730-3p, that were enriched in both the exosome and microvesicle fraction in a P2X7-dependent fashion. Interestingly, upon transfection, these miRNAs promoted melanoma cell growth or migration, and their vesicular release was minimized by P2X7 antagonism. Our data unveil an exosome/microvesicle and miRNA-dependent mechanism for the pro-metastatic activity of the P2X7 receptor and highlight this receptor as a suitable prognostic biomarker and therapeutic target in malignant melanoma.
The recently discovered mitochondrial calcium uniporter (MCU) promotes Ca2+ accumulation into the mitochondrial matrix 1, 2. We identified in silico miR-25 as a cancer-related MCU-targeting microRNA ...family and demonstrate that its overexpression in HeLa cells drastically reduces MCU levels and mitochondrial Ca2+ uptake, while leaving other mitochondrial parameters and cytosolic Ca2+ signals unaffected. In human colon cancers and cancer-derived cells, miR-25 is overexpressed and MCU accordingly silenced. miR-25-dependent reduction of mitochondrial Ca2+ uptake correlates with resistance to apoptotic challenges and can be reversed by anti-miR-25 overexpression. Overall, the data demonstrate that microRNA targeting of mitochondrial Ca2+ signaling favors cancer cell survival, thus providing mechanistic insight into the role of mitochondria in tumorigenesis and identifying a novel therapeutic target in neoplasia.
► miR-25 regulates intracellular calcium homeostasis ► Mitochondrial calcium uniporter (MCU) is a target of miR-25 ► MCU plays a critical role in apoptosis and tumorigenesis ► MCU is downregulated in different cancer cell lines and in human colonic adenocarcinoma
The ‘classic’ view of molecular oncology indicates that cancer is a genetic disease involving tumor suppressor and oncogenic proteins. However, in the recent years, it has been demonstrated that ...small regulatory non-coding RNAs (ncRNAs) named microRNAs (miRNAs) are involved in human tumorigenesis, thus revealing a new layer in the molecular architecture of human cancer. Gene expression studies revealed that hundreds of miRNAs are deregulated in cancer cells and functional studies clarified that miRNAs are involved in all the molecular and biological processes that drive tumorigenesis. Here, we summarize the recent advances in miRNA involvement in human cancer and illustrate the benefits of using these knowledge for medical practice. New diagnostic classifiers based on miRNAs will soon be available for medical practitioners and, even more importantly, miRNAs may become novel anti-cancer tools.
MicroRNAs (miRNA) have rapidly emerged as modulators of gene expression in cancer in which they may have great diagnostic and therapeutic import. MicroRNA-199a-3p (miR-199a-3p) is downregulated in ...several human malignancies including hepatocellular carcinoma (HCC). Here, we show that miR-199a-3p targets mammalian target of rapamycin (mTOR) and c-Met in HCC cells. Restoring attenuated levels of miR-199a-3p in HCC cells led to G(1)-phase cell cycle arrest, reduced invasive capability, enhanced susceptibility to hypoxia, and increased sensitivity to doxorubicin-induced apoptosis. These in vitro findings were confirmed by an analysis of human HCC tissues, which revealed an inverse correlation linking miR-199a-3p and mTOR as well as a shorter time to recurrence after HCC resection in patients with lower miR-199a-3p expression. These results suggest that tactics to regulate mTOR and c-Met by elevating levels of miR-199a-3p may have therapeutic benefits in highly lethal cancers such as HCC.
The performance of circulating biomarkers for the diagnosis of hepatocellular carcinoma (HCC) is sub-optimal. In this study we tested circulating microRNAs as biomarkers for HCC in cirrhotic patients ...by performing a two stage study: a discovery phase conducted by microarray and a validation phase performed by qRT-PCR in an independent series of 118 patients. Beside miRNAs emerged from the discovery phase, miR-21, miR-221, miR-519d were also tested in the validation setting on the basis of literary and tissue findings. Deregulated microRNAs were assayed in HCC-derived cells in the intracellular compartment, cell culture supernatant and exosomal fraction. Serum and tissue microRNA levels were compared in 14 patients surgically treated for HCC. From the discovery study, it emerged that seven circulating microRNAs were differentially expressed in cirrhotic patients with and without HCC. In the validation set, miR-939, miR-595 and miR-519d were shown to differentiate cirrhotic patients with and without HCC. MiR-939 and miR-595 are independent factors for HCC. ROC curves of miR-939, miR-595 and miR-519d displayed that AUC was higher than AFP. An exosomal secretion of miR-519d, miR-21, miR-221 and miR-1228 and a correlation between circulating and tissue levels of miR-519d, miR-494 and miR-21 were found in HCC patients. Therefore, we show that circulating microRNAs deserve attention as non-invasive biomarkers in the diagnostic setting of HCC and that exosomal secretion contributes to discharging a subset of microRNAs into the extracellular compartment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The identification of target genes is a key step for assessing the role of aberrantly expressed microRNAs (miRNA) in human cancer and for the further development of miRNA-based gene therapy. MiR-122 ...is a liver-specific miRNA accounting for 70% of the total miRNA population. Its down-regulation is a common feature of both human and mouse hepatocellular carcinoma (HCC). We have previously shown that miR-122 can regulate the expression of cyclin G1, whose high levels have been reported in several human cancers. We evaluated the role of miR-122 and cyclin G1 expression in hepatocarcinogenesis and in response to treatment with doxorubicin and their relevance on survival and time to recurrence (TTR) of HCC patients. We proved that, by modulating cyclin G1, miR-122 influences p53 protein stability and transcriptional activity and reduces invasion capability of HCC-derived cell lines. In addition, in a therapeutic perspective, we assayed the effects of a restored miR-122 expression in triggering doxorubicin-induced apoptosis and we proved that miR-122, as well as cyclin G1 silencing, increases sensitivity to doxorubicin challenge. In patients resected for HCC, lower miR-122 levels were associated with a shorter TTR, whereas higher cyclin G1 expression was related to a lower survival, suggesting that miR-122 might represent an effective molecular target for HCC. Our findings establish a basis toward the development of combined chemo- and miRNA-based therapy for HCC treatment.
Recent studies suggested that colorectal cancer influences the types and quantity of nucleic acids - especially microRNAs - detected in the bloodstream. Concentration of circulating (cell-free) ...microRNAs, and possibly of other non-coding RNAs, could therefore serve as valuable colorectal cancer biomarker and could deliver insight into the disease process. This chapter addresses the recent discoveries on circulating microRNA and long non-coding RNA as diagnostic or prognostic biomarkers in colorectal cancer.
MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translation repression or RNA degradation. Their aberrant expression may ...be involved in human diseases, including cancer. Indeed, miRNA aberrant expression has been previously found in human chronic lymphocytic leukemias, where miRNA signatures were associated with specific clinicobiological features. Here, we show that, compared with normal breast tissue, miRNAs are also aberrantly expressed in human breast cancer. The overall miRNA expression could clearly separate normal versus cancer tissues, with the most significantly deregulated miRNAs being mir-125b, mir-145, mir-21, and mir-155. Results were confirmed by microarray and Northern blot analyses. We could identify miRNAs whose expression was correlated with specific breast cancer biopathologic features, such as estrogen and progesterone receptor expression, tumor stage, vascular invasion, or proliferation index.
Abstract Objectives Micro-RNAs are a group of small noncoding RNAs with modulator activity of gene expression. Recently, micro-RNA genes were found abnormally expressed in several types of cancers. ...To study the role of the micro-RNAs in human kidney and bladder cancer, we analyzed the expression profile of 245 micro-RNAs in kidney and bladder primary tumors. Methods and materials A total of 27 kidney specimens (20 carcinomas, 4 benign renal tumors, and 3 normal parenchyma) and 27 bladder specimens (25 urothelial carcinomas and 2 normal mucosa) were included in the study. Total RNA was used for hybridization on an oligonucleotide microchip for micro-RNA profiling developed in our laboratories. This microchip contains 368 probes in triplicate, corresponding to 245 human and mouse micro-RNA genes. Results A set of 4 human micro-RNAs ( miR-28, miR-185, miR-27 , and let-7f-2 ) were found significantly up-regulated in renal cell carcinoma ( P < 0.05) compared to normal kidney. Human micro-RNAs miR-223 , miR-26b , miR-221 , miR-103-1 , miR-185 , miR-23b , miR-203 , miR-17-5p , miR-23a , and miR-205 were significantly up-regulated in bladder cancers ( P < 0.05) compared to normal bladder mucosa. Of the kidney cancers studied, there was no differential micro-RNA expression across various stages, whereas with increasing tumor-nodes-metastasis staging in bladder cancer, miR-26b showed a moderate decreasing trend ( P = 0.082). Conclusions Our results show that different micro-RNAs are deregulated in kidney and bladder cancer, suggesting the involvement of these genes in the development and progression of these malignancies. Further studies are needed to clarify the role of micro-RNAs in neoplastic transformation and to test the potential clinical usefulness of micro-RNAs microarrays as diagnostic and prognostic tool.
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