Publications

Abstract Purpose: The DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) inhibits the killing of tumor cells by alkylating agents, and its loss in cancer cells is associated with hypermethylation of the MGMT CpG island. Thus, methylation of MGMT has been correlated with the clinical response to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in primary gliomas. Here, we investigate whether the presence of MGMT methylation in gliomas is also a good predictor of response to another emergent alkylating agent, temozolomide. Experimental Design: Using a methylation-specific PCR approach, we assessed the methylation status of the CpG island of MGMT in 92 glioma patients who received temozolomide as first-line chemotherapy or as treatment for relapses. Results: Methylation of the MGMT promoter positively correlated with the clinical response in the glioma patients receiving temozolomide as first-line chemotherapy (n = 40). Eight of 12 patients with MGMT-methylated tumors (66.7%) had a partial or complete response, compared with 7 of 28 patients with unmethylated tumors (25.0%; P = 0.030). We also found a positive association between MGMT methylation and clinical response in those patients receiving BCNU (n = 35, P = 0.041) or procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (n = 17, P = 0.043) as first-line chemotherapy. Overall, if we analyze the clinical response of all of the first-line chemotherapy treatments with temozolomide, BCNU, and procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea as a group in relation to the MGMT methylation status, MGMT hypermethylation was strongly associated with the presence of partial or complete clinical response (P < 0.001). Finally, the MGMT methylation status determined in the initial glioma tumor did not correlate with the clinical response to temozolomide when this drug was administered as treatment for relapses (P = 0.729). Conclusions: MGMT methylation predicts the clinical response of primary gliomas to first-line chemotherapy with the alkylating agent temozolomide. These results may open up possibilities for more customized treatments of human brain tumors.

Epigenetic deregulation revealed by altered profiles of DNA methylation and histone modifications is a frequent event in cancer cells and results in abnormal patterns of gene expression. Cancer silenced genes constitute prime therapeutic targets and considerable progress has been made in the epigenetic characterization of the chromatin scenarios associated with their inactivation and drug induced reactivation. Despite these advances, the mechanisms involved in the maintenance or resetting of epigenetic states in both physiological and pharmacological situations are poorly known. To get insights into the dynamics of chromatin regulation upon drug-induced reactivation, we have investigated the epigenetic profiles of two chromosomal regions undergoing long range epigenetic silencing in colon cancer cells in time-course settings after exposure of cells to chromatin reactivating agents. The DNA methylation states and the balance between histone H3K4 methylation and H3K27 methylation marks clearly define groups of genes with alternative responses to therapy. We show that the expected epigenetic remodeling induced by the reactivating drugs, just achieves a transient disruption of the bivalent states, which overcome the treatment and restore the transcriptional silencing approximately four weeks after drug exposure. The interplay between DNA methylation and bivalent histone marks appears to configure a plastic but stable chromatin scenario that is fully restored in silenced genes after drug withdrawal. These data suggest that improvement of epigenetic therapies may be achieved by designing strategies with long lasting effects.

<p>Heatmap representing the patients' methylation profile for the four genes involved in the prediction model and Nomogram for prediction of cancer risk, constructed using the coefficients of our combined logistic regression model as weights.</p>

DNA methylation is an epigenetic modification involved in regulatory processes such as cell differentiation during development, X-chromosome inactivation, genomic imprinting and susceptibility to complex disease. However, the dynamics of DNA methylation changes between humans and their closest relatives are still poorly understood. We performed a comparative analysis of CpG methylation patterns between 9 humans and 23 primate samples including all species of great apes (chimpanzee, bonobo, gorilla and orangutan) using Illumina Methylation450 bead arrays. Our analysis identified ∼800 genes with significantly altered methylation patterns among the great apes, including ∼170 genes with a methylation pattern unique to human. Some of these are known to be involved in developmental and neurological features, suggesting that epigenetic changes have been frequent during recent human and primate evolution. We identified a significant positive relationship between the rate of coding variation and alterations of methylation at the promoter level, indicative of co-occurrence between evolution of protein sequence and gene regulation. In contrast, and supporting the idea that many phenotypic differences between humans and great apes are not due to amino acid differences, our analysis also identified 184 genes that are perfectly conserved at protein level between human and chimpanzee, yet show significant epigenetic differences between these two species. We conclude that epigenetic alterations are an important force during primate evolution and have been under-explored in evolutionary comparative genomics.

<div>Abstract<p>Alterations in epigenetic marks, such as DNA methylation, represent a hallmark of cancer that has been successfully exploited for therapy in myeloid malignancies. Hypomethylating agents (HMA), such as azacitidine, have become standard-of-care therapy to treat myelodysplastic syndromes (MDS), myeloid neoplasms that can evolve into acute myeloid leukemia. However, our capacity to identify who will respond to HMAs, and the duration of response, remains limited. To shed light on this question, we have leveraged the unprecedented analytic power of single-cell technologies to simultaneously map the genome and immunoproteome of MDS samples throughout clinical evolution. We were able to chart the architecture and evolution of molecular clones in precious paired bone marrow MDS samples at diagnosis and posttreatment to show that a combined imbalance of specific cell lineages with diverse mutational profiles is associated with the clinical response of patients with MDS to hypomethylating therapy.</p>Significance:<p>MDS are myeloid clonal hemopathies with a low 5-year survival rate, and approximately half of the cases do not respond to standard HMA therapy. Our innovative single-cell multiomics approach offers valuable biological insights and potential biomarkers associated with the demethylating agent efficacy. It also identifies vulnerabilities that can be targeted using personalized combinations of small drugs and antibodies.</p></div>

<p>Supplementary Figure 4. Effect of KAT6B shRNA-mediated depletion in the growth rate according to the XTT assay</p>

Additional file 5: Supplementary Figure 1. Leave-one-out permutation analysis plot for AD signature among individuals at high genetic predisposition to AD obtained by leaving out the SNP indicated and repeating the Inverse-Variance Weighted method with the rest of the instrumental variables. Supplementary Figure 2. Leave-one-out permutation analysis plot for Aging signature among individuals at high genetic predisposition to AD, obtained by leaving out the SNP indicated and repeating the Inverse-Variance Weighted method with the rest of the instrumental variables. Supplementary Figure 3. Leave-one-out permutation analysis plot for Aβ ratio among APOE-ɛ4 non-carriers obtained by leaving out the SNP indicated and repeating the Inverse-Variance Weighted method with the rest of the instrumental variables. Supplementary Figure 4. Leave-one-out permutation analysis plot for NfL among APOE-ɛ4 non-carriers obtained by leaving out the SNP indicated and repeating the Inverse-Variance Weighted method with the rest of the instrumental variables. Supplementary Figure 5. Leave-one-out permutation analysis plot for p-tau among individuals at high genetic predisposition to AD, obtained by leaving out the SNP indicated and repeating the Inverse-Variance Weighted method with the rest of the instrumental variables.

ABSTRACT Background Early detection through screening programs has proven to be the most effective strategy to reduce the incidence and mortality of colorectal cancer. The most widely implemented non-invasive screening test is the fecal immunochemical test, which presents an inadequate sensitivity for the detection of precancerous advanced adenomas. This fact, together with the modest participation rates in screening programs, highlights the need for a blood test that could improve both the adherence to screening and the selection to colonoscopy. Methods In this study, we conducted a serum-based discovery and validation of circulating cell-free DNA (cfDNA) methylation biomarkers for colorectal cancer screening in a multicentre cohort of 433 serum samples including healthy controls, benign pathologies, advanced adenomas, and colorectal cancer. First, we performed an epigenome-wide methylation analysis with the MethylationEPIC array in 280 cfDNA samples using a pooling approach, followed by a robust prioritization of candidate biomarkers for the joint detection of advanced adenomas and colorectal cancer (advanced neoplasia). Then, candidate biomarkers were validated by pyrosequencing in independent individual 153 cfDNA samples. Results We report GALNT9 , UPF3A , WARS , and LDB2 as new non-invasive methylation biomarkers for the early detection of colorectal advanced neoplasia. A model composed of GALNT9 , UPF3A , WARS , and LDB2 reported a sensitivity of 62.1% and a specificity of 97.4% for the detection of advanced neoplasia. On the other hand, the combination of GALNT9 and UPF3A by logistic regression discriminated advanced neoplasia with 78.8% sensitivity and 100% specificity, outperforming the commonly used fecal immunochemical test and the methylated SEPT9 blood test. Conclusions Serum methylation levels of GALNT9 , UPF3A , WARS , and LDB2 represent highly specific and sensitive novel blood-based biomarkers for the detection of colorectal cancer and premalignant advanced adenomas of both distal and proximal locations. The reported results show the feasibility of DNA sample pooling strategies for biomarker discovery. Overall, this study highlights the utility of cfDNA methylation for the early detection of colorectal neoplasia, with the potential to be implemented as a non-invasive test for colorectal cancer screening.

<p>(A) Immunoblotting was performed to measure protein levels in parental and resistant clones for pAKT/AKT and pERK/ERK in three independent experiments. GAPDH was used as a loading control. (B) Protein quantification was done normalizing first to GAPDH and then to total protein. Barplot represents the quantification in each of the independent experiments, parental in grey, resistant in red. Median and standard error of the mean for parental and resistant levels in the three experiments. Moderated t-test was performed to determine statistically significance (p<0.05).</p>

<p>Sequences of sgRNAs used for induction of ERBB4 transcription by CRISPR activation technique.</p>

Abstract Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has become a fundamental procedure for gastrointestinal and lung cancer staging. However, there is growing evidence that micrometastases are present in lymph nodes, which cannot be detected with standard pathological methods. The aim of this study was to evaluate whether hypermethylation gene promoter analysis was feasible on samples obtained by EUS-FNA from lymph nodes, as well as to establish the usefulness of this strategy for the detection of micrometastases in patients with gastrointestinal and non-small cell lung cancer. Suspicious lymph nodes based on EUS findings from consecutive patients with esophageal, gastric, rectal, and non-small cell lung cancer were sampled by EUS-FNA. Hypermethylation analysis of the MGMT, p16INK4a, and p14ARF gene promoter CpG islands were performed by methylation-specific PCR. Effectiveness of conventional cytology, methylation analysis, and their combination were established with respect to the definitive diagnosis. Twenty-seven patients were included, thus representing a total of 42 lymph nodes (esophageal cancer, n = 11; rectal cancer, n = 7; gastric cancer, n = 3; and lung cancer, n = 21). According to definitive diagnosis, 21 (50%) corresponded to metastatic lymph nodes. Sensitivity, specificity, and overall accuracy of conventional cytology were 76%, 100%, and 88%, respectively, whereas the corresponding values for the methylation analysis were 81%, 67%, and 74%, respectively. Combination of both techniques increased sensitivity (90%) but decreased specificity (67%) with respect to conventional cytology. In conclusion, it is feasible to detect occult neoplastic cells in EUS-FNA samples by hypermethylation gene promoter analysis. Moreover, addition of methylation analysis to conventional cytology may increase its sensitivity at the expenses of a decrease in its specificity.

Proteases have long been associated with tumor progression, given their ability to degrade extracellular matrix components and facilitate invasion and metastasis. However, recent findings indicate that different proteases can also act as tumor-suppressor enzymes. We have recently reported that lung carcinoma cells expressing the ADAMTS-12 metalloprotease show a remarkable impairment of growth in immunodeficient mice as compared with parental cells. Here, we show that ADAMTS12 promoter is hypermethylated in cancer cell lines and tumor tissues. Interestingly, ADAMTS12 expression in the stromal cells surrounding epithelial malignant cells is higher than in the paired normal tissues. Moreover, the expression of this metalloprotease in colon fibroblasts co-cultured with colon cancer cell lines is higher than in those cultured alone. Furthermore, the expression of ADAMTS-12 by these fibroblasts is linked with an anti-proliferative effect on tumor cells. Based on these findings, we hypothesize that ADAMTS-12 is a novel anti-tumor protease that can reduce the proliferative properties of tumor cells. This function is lost by epigenetic silencing in tumor cells, but concurrently induced in stromal cells, probably as part of a response of the normal tissue aimed at controlling the progression of cancer.