Tania Díaz

miR-34a as a prognostic marker of relapse in surgically resected non-small-cell lung cancer

MicroRNAs (miRNAs) have been identified as promising prognostic markers in non-small-cell lung cancer (NSCLC) since they play an important role in oncogenesis. The miR-34 family is composed of three miRNAs (miR-34a, miR-34b and miR-34c) that are part of the p53 network and whose expression is directly induced by p53 in response to DNA damage or oncogenic stress. We have analyzed the impact of miR-34 expression on relapse and overall survival in surgically resected NSCLC patients. For this purpose, we used stem-loop reverse transcription-polymerase chain reaction to analyze the expression of the miR-34 family in paired tumor and normal tissue from 70 surgically resected NSCLC patients who received no postsurgical treatment until relapse. In addition, in patients with sufficient tumor tissue, we assessed p53 mutations and the methylation status of the MIRN34A gene promoter region and correlated these findings with miR-34a expression. Molecular findings were correlated with relapse and overall survival. The miR-34 family was downregulated in tumor compared with normal tissue, and low levels of miR-34a expression were correlated with a high probability of relapse (P = 0.04). A relation was also found between MIRN34A methylation and miR-34a expression (P = 0.008). Patients with both p53 mutations and low miR-34a levels had the highest probability of relapse (P = 0.001). In the multivariate analysis, miR-34a expression emerged as an independent prognostic marker for relapse. In summary, we have identified miR-34a as a novel prognostic marker in NSCLC patients, providing a potential mechanism for estimating a patients risk of disease recurrence and a useful tool to help guide treatment decisions.

Overlapping expression of microRNAs in human embryonic colon and colorectal cancer.

MicroRNAs (miRNAs) are essential for regulating cell differentiation and maintaining the pluripotent state of stem cells. Although dysregulation of specific miRNAs has been associated with certain types of cancer, to date no evidence has linked miRNA expression in embryonic and tumor tissues. We assessed the expression of mature miRNAs in human embryonic colon tissue, and in colorectal cancer and paired normal colon tissue. Overlapping miRNA expression was detected between embryonic colonic mucosa and colorectal cancer. We have found that the miR-17-92 cluster and its target, E2F1, exhibit a similar pattern of expression in human colon development and colonic carcinogenesis, regulating cell proliferation in both cases. In situ hybridization confirmed the high level of expression of miR-17-5p in the crypt progenitor compartment. We conclude that miRNA pathways play a major role in both embryonic development and neoplastic transformation of the colonic epithelium.

Regulation of JAK2 by miR-135a: prognostic impact in classic Hodgkin lymphoma.

The behavior of classic Hodgkin lymphoma (cHL) is determined by both the intrinsic features of the tumor cells and the characteristics of the microenvironment, making the analysis of entire lymph nodes an effective approach to understanding the disease. We examined the influence of our previously reported 25-microRNA signature for cHL on clinical outcome in 89 homogeneously treated cHL patients with a median follow-up of 80 months. Patients with low miR-135a expression had a higher probability of relapse (P = .04) and a shorter disease-free survival (P = .02). Functional analysis of cHL cell lines showed that mature miR-135a levels increased after pre-miR-135a transfection, causing apoptosis and decreased cell growth. Target analysis showed a direct regulation by miR-135a of JAK2, a cytoplasmic tyrosine kinase involved in a specific subset of cytokine receptor signaling pathways. miR-135a-mediated JAK2 down-regulation led to decreased mRNA and protein levels of the antiapoptotic gene Bcl-xL, suggesting a role for Bcl-xL in miR-135a/JAK2-mediated apoptosis. Our findings confirm the critical role of miR-135a in the survival of cHL cells and in the prognosis of cHL patients, indicating that novel treatment approaches targeting miR-135a may potentially benefit these patients.

Hematopoiesis-related microRNA expression in myelodysplastic syndromes

MicroRNAs (miRNAs) are negative regulators of expression of genes involved in hematopoiesis. The present study sought to link hematopoiesis-relevant miRNAs with myelodysplastic syndromes (MDS) and MDS progression to acute myeloid leukemia (AML). We assessed 25 mature miRNAs in total RNA from bone marrow (BM) and peripheral blood (PB) of 25 newly diagnosed patients with MDS and 12 controls. Twelve miRNAs in BM and six in PB were differentially expressed between patients with MDS and controls. Three of these miRNAs, belonging to the cluster 17–92, were overexpressed in both BM and PB. miR-15a in BM ( p = 0.034) and miR-16 in PB ( p = 0.005) were differentially expressed between low-risk and high-risk groups. miR-222 ( p = 0.0023) and miR-181a ( p = 0.014) expression was higher in AML than in MDS in both BM and PB. This study adds further evidence to the role of miRNAs in the pathogenesis of MDS and their transformation into AML.

Tumour CD133 mRNA expression and clinical outcome in surgically resected colorectal cancer patients

BACKGROUND Human prominin-1 (CD133) is a novel pentaspan membrane protein which was originally classified as a marker of primitive haematopoietic and neural stem cells. Cancer stem cells have been isolated and expanded from leukaemia and several solid tumours, and have been associated with metastasis, chemoresistance and relapse. CD133 is recognised as a stem cell marker and is capable of identifying a tumour-initiating subpopulation in brain, colon, melanoma and other solid tumours. METHODS We assessed CD133 mRNA expression levels by RT-QPCR in tumour and matched normal tissue from 64 stages I-III colorectal cancer (CRC) patients and correlated tumour CD133 levels with clinicopathological characteristics and clinical outcome. RESULTS In four patients, CD133 mRNA was not expressed in tumour or in normal tissue. In the remaining 60 patients, expression levels were higher in tumour than in normal tissue (p=0.001). Higher levels of CD133 expression were associated with shorter relapse-free interval (RFI) (p=0.004) and overall survival (OS) (p<0.0001). In the multivariate analyses, CD133 levels emerged as a prognostic marker for RFI and OS. CONCLUSIONS We have observed longer RFI and OS in patients with lower levels of CD133, regardless of adjuvant treatment and other clinical characteristics. If these findings are confirmed in larger prospective studies, CD133 assessment may prove useful for new diagnostic and therapeutic procedures for CRC patients.

Prognostic implications of miR-16 expression levels in resected non-small-cell lung cancer.

MicroRNAs are novel regulators of gene expression that are linked to the main oncogene networks, including the p53 pathway. p53 regulates the maturation process of miR‐16 and miR‐143. We analyzed the role as prognostic markers of miR‐16 and miR‐143 in 70 non‐small‐cell lung cancer (NSCLC) patients.

A Dual Role for KRT81: A miR-SNP Associated with Recurrence in Non-Small-Cell Lung Cancer and a Novel Marker of Squamous Cell Lung Carcinoma

MicroRNAs (miRNAs) play an important role in carcinogenesis through the regulation of their target genes. miRNA-related single nucleotide polymorphisms (miR-SNPs) can affect miRNA biogenesis and target sites and can alter microRNA expression and functions. We examined 11 miR-SNPs, including 5 in microRNA genes, 3 in microRNA binding sites and 3 in microRNA-processing machinery components, and evaluated time to recurrence (TTR) according to miR-SNP genotypes in 175 surgically resected non-small-cell lung cancer (NSCLC) patients. Significant differences in TTR were found according to KRT81 rs3660 (median TTR: 20.3 months for the CC genotype versus 86.8 months for the CG or GG genotype; P = 0.003) and XPO5 rs11077 (median TTR: 24.7 months for the AA genotype versus 73.1 months for the AC or CC genotypes; P = 0.029). Moreover, when patients were divided according to stage, these differences were maintained for stage I patients (P = 0.002 for KRT81 rs3660; P<0.001 for XPO5 rs11077). When patients were divided into sub-groups according to histology, the effect of the KRT81 rs3660 genotype on TTR was significant in patients with squamous cell carcinoma (P = 0.004) but not in those with adenocarcinoma. In the multivariate analyses, the KRT81 rs3660 CC genotype (OR = 1.8; P = 0.023) and the XPO5 rs11077 AA genotype (OR = 1.77; P = 0.026) emerged as independent variables influencing TTR. Immunohistochemical analyses in 80 lung specimens showed that 95% of squamous cell carcinomas were positive for KRT81, compared to only 19% of adenocarcinomas (P<0.0001). In conclusion, miR-SNPs are a novel class of SNPs that can add useful prognostic information on the clinical outcome of resected NSCLC patients and may be a potential key tool for selecting high-risk stage I patients. Moreover, KRT81 has emerged as a promising immunohistochemical marker for the identification of squamous cell lung carcinoma.

Lestaurtinib Inhibition of the JAK/STAT Signaling Pathway in Hodgkin Lymphoma Inhibits Proliferation and Induces Apoptosis

Standard cytotoxic chemotherapy for Hodgkin Lymphoma (HL) has changed little in 30 years; the treatment for patients with relapsed or refractory disease remains challenging and novel agents are under development. JAK/STAT constitutive activation plays an important role in the pathogenesis of HL. Lestaurtinib is an orally bioavailable multikinase inhibitor that has recently been shown to inhibit JAK2 in myeloproliferative disorders. The potential role of Lestaurtinib in HL therapy is unknown. We have analyzed the effect of Lestaurtinib treatment in five HL cell lines from refractory patients, L-428, L-1236, L-540, HDML-2 and HD-MY-Z. At 48 h, a dose-dependent cell growth inhibition (23%–66% at 300 nM) and apoptotic increment (10%–64% at 300 nM) were observed. Moreover, Lestaurtinib inhibited JAK2, STAT5 and STAT3 phosphorylation and reduced the mRNA expression of its downstream antiapoptotic target Bcl-xL. In addition, we have analyzed the effect of Lestaurtinib treatment in lymph nodes from four classic HL patients. We observed a decrease in cell viability at 24 hours of treatment in three patients (mean decrease of 27% at 300 nM). Our findings provide, for the first time, a molecular rationale for testing JAK2 inhibitors, specifically Lestaurtinib, in HL patients.

Impact of MiRSNPs on Survival and Progression in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation

Purpose: A distinctive new group of polymorphisms is constituted by single-nucleotide polymorphism (SNP) in miRNA processing machinery in miRNA precursor molecules and in miRNA-binding sites, known as miRSNPs. The aim of this study was to ascertain the prognostic impact of six miRSNPs in patients with multiple myeloma and analyze the functional consequences. Experimental Design: One hundred and thirty-seven patients with chemosensitive multiple myeloma (73M/64F) intensified with autologous stem cell transplantation (ASCT) were studied. The median follow-up was 4 years. The genes and SNPs evaluated in genomic DNA by allelic discrimination were KRT81 (rs3660), AFF1 (rs17703261), FAM179b (rs1053667), and MIR196A2 (rs11614913) for miRNA target genes and TRBP (rs784567) and XPO5 (rs11077) for miRNA biogenesis pathway. Results: Overall survival (OS) was significantly longer in patients with KRT81 rs3660 C/C variant (P = 0.037). Functional analysis showed that the presence of C variant in KRT81 3′ untranslated region (UTR) is related with a reduction of the protein levels. Moreover, the reduction of KRT81 protein levels by siRNA in multiple myeloma cell lines is related to a decreased proliferation. On the other hand, OS was significantly longer in patients with C/C or A/C variant in XPO5 rs11077 (P = 0.012). There was also a significantly longer progression-free survival (PFS) for this SNP (P = 0.013). This SNP retained its prognostic impact on PFS and OS in a multivariate regression analysis (P = 0.028 and P = 0.014, respectively). Conclusion: This is the first report that relates miRSNPs with prognosis in multiple myeloma either in a keratin gene (KRT81), target of diverse miRNA multiple myeloma clusters, or in the miRNA biogenesis pathway–related protein exportin-5. Clin Cancer Res; 18(13); 3697–704. ©2012 AACR.

Role of miR-200 family members in survival of colorectal cancer patients treated with fluoropyrimidines

Surgery is the standard treatment for colorectal cancer (CRC), and adjuvant chemotherapy has been shown to be effective in stage III but less so in stage II. We have analyzed the expression of the miR‐200 family in tissue samples from resected CRC patients and correlated our findings with survival to adjuvant treatment with fluoropyrimidines.