LncRNA SOX9-AS1 triggers a transcriptional program involved in lipid metabolic reprogramming, cell migration and invasion in triple-negative breast cancer.

At the molecular level, triple-negative breast cancer (TNBC) is frequently categorized as PAM50 basal-like subtype, but despite the advances in molecular analyses, the clinical outcome for these subtypes is uncertain. Long non-coding RNAs (lncRNAs) are master regulators of genes involved in hallmarks of cancer, which makes them suitable biomarkers for breast cancer (BRCA) diagnosis and prognosis. Here, we evaluated the regulatory role of lncRNA SOX9-AS1 in these subtypes. Using the BRCA-TCGA cohort, we observed that SOX9-AS1 was significantly overexpressed in basal-like and TNBC in comparison with other BRCA subtypes. Survival analyzes showed that SOX9-AS1 overexpression was associated with a favorable prognosis in TNBC and basal-like patients. To study the functions of SOX9-AS1, we determined the expression levels in a panel of nine BRCA cell lines finding increased levels in MDA-MB-468 and HCC1187 TNBC. Using subcellular fractionation in these cell lines, we ascertained that SOX9-AS1 was located in the cytoplasmic compartment. In addition, we performed SOX9-AS1 gene silencing using two short-harping constructs, which were transfected in both cell models and performed a genome-wide RNA-seq analysis. Data showed that 351 lncRNAs and 740 mRNAs were differentially expressed in MDA-MB-468 while 56 lncRNAs and 100 mRNAs were modulated in HCC1187 cells (Log2FC < - 1.5 and > 1.5, p.adj value < 0.05). Pathway analysis revealed that the protein-encoding genes potentially regulate lipid metabolic reprogramming, and epithelial-mesenchymal transition (EMT). Expression of lipid metabolic-related genes LIPE, REEP6, GABRE, FBP1, SCD1, UGT2B11, APOC1 was confirmed by RT-qPCR. Functional analysis demonstrated that the knockdown of SOX9-AS1 increases the triglyceride synthesis, cell migration and invasion in both two TNBC cell lines. In conclusion, high SOX9-AS1 expression predicts an improved clinical course in patients, while the loss of SOX9-AS1 expression enhances the aggressiveness of TNBC cells.

LINC00460 Is a Dual Biomarker That Acts as a Predictor for Increased Prognosis in Basal-Like Breast Cancer and Potentially Regulates Immunogenic and Differentiation-Related Genes.

Breast cancer (BRCA) is a serious public health problem, as it is the most frequent malignant tumor in women worldwide. BRCA is a molecularly heterogeneous disease, particularly at gene expression (mRNAs) level. Recent evidence shows that coding RNAs represent only 34% of the total transcriptome in a human cell. The rest of the 66% of RNAs are non-coding, so we might be missing relevant biological, clinical or regulatory information. In this report, we identified two novel tumor types from TCGA with LINC00460 deregulation. We used survival analysis to demonstrate that LINC00460 expression is a marker for poor overall (OS), relapse-free (RFS) and distant metastasis-free survival (DMFS) in basal-like BRCA patients. LINC00460 expression is a potential marker for aggressive phenotypes in distinct tumors, including HPV-negative HNSC, stage IV KIRC, locally advanced lung cancer and basal-like BRCA. We show that the LINC00460 prognostic expression effect is tissue-specific, since its upregulation can predict poor OS in some tumors, but also predicts an improved clinical course in BRCA patients. We found that the LINC00460 expression is significantly enriched in the Basal-like 2 (BL2) TNBC subtype and potentially regulates the WNT differentiation pathway. LINC00460 can also modulate a plethora of immunogenic related genes in BRCA, such as SFRP5, FOSL1, IFNK, CSF2, DUSP7 and IL1A and interacts with miR-103-a-1, in-silico, which, in turn, can no longer target WNT7A. Finally, LINC00460:WNT7A ratio constitutes a composite marker for decreased OS and DMFS in Basal-like BRCA, and can predict anthracycline therapy response in ER-BRCA patients. This evidence confirms that LINC00460 is a master regulator in BRCA molecular circuits and influences clinical outcome.

FAM83H-AS1 is a potential modulator of cancer driver genes across different tumors and a prognostic marker for ER/PR + BRCA patients.

Breast cancer (BRCA) is a serious public health problem, as it is the most frequent malignant tumor in women worldwide. BRCA is a molecularly heterogenic disease, particularly at gene expression (mRNAs) level. Recent evidence shows that coding RNAs represent only 34% of the total transcriptome in a human cell. The rest of the 66% of RNAs are non-coding, so we might be missing relevant biological, clinical or regulatory information. In this report, we identified nine novel tumor types from TCGA with FAM83H-AS1 deregulation. We used survival analysis to demonstrate that FAM83H-AS1 expression is a marker for poor survival in IHC-detected ER and PR positive BRCA patients and found a significant correlation between FAM83H-AS1 overexpression and tamoxifen resistance. Estrogen and Progesterone receptor expression levels interact with FAM83H-AS1 to potentiate its effect in OS prediction. FAM83H-AS1 silencing impairs two important breast cancer related pathways: cell migration and cell death. Among the most relevant potential FAM83H-AS1 gene targets, we found p63 and claudin 1 (CLDN1) to be deregulated after FAM83H-AS1 knockdown. Using correlation analysis, we show that FAM83H-AS1 can regulate a plethora of cancer-related genes across multiple tumor types, including BRCA. This evidence suggests that FAM83H-AS1 is a master regulator in different cancer types, and BRCA in particular.

A lncRNA landscape in breast cancer reveals a potential role for AC009283.1 in proliferation and apoptosis in HER2-enriched subtype.

Breast cancer is the most commonly diagnosed neoplasm in women worldwide with a well-recognized heterogeneous pathology, classified into four molecular subtypes: Luminal A, Luminal B, HER2-enriched and Basal-like, each one with different biological and clinical characteristics. Long non-coding RNAs (lncRNAs) represent 33% of the human transcriptome and play critical roles in breast carcinogenesis, but most of their functions are still unknown. Therefore, cancer research could benefit from continued exploration into the biology of lncRNAs in this neoplasm. We characterized lncRNA expression portraits in 74 breast tumors belonging to the four molecular subtypes using transcriptome microarrays. To infer the biological role of the deregulated lncRNAs in the molecular subtypes, we performed co-expression analysis of lncRNA-mRNA and gene ontology analysis. We identified 307 deregulated lncRNAs in tumor compared to normal tissue and 354 deregulated lncRNAs among the different molecular subtypes. Through co-expression analysis between lncRNAs and protein-coding genes, along with gene enrichment analysis, we inferred the potential function of the most deregulated lncRNAs in each molecular subtype, and independently validated our results taking advantage of TCGA data. Overexpression of the AC009283.1 was observed in the HER2-enriched subtype and it is localized in an amplification zone at chromosome 17q12, suggesting it to be a potential tumorigenic lncRNA. The functional role of lncRNA AC009283.1 was examined through loss of function assays in vitro and determining its impact on global gene expression. These studies revealed that AC009283.1 regulates genes involved in proliferation, cell cycle and apoptosis in a HER2 cellular model. We further confirmed these findings through ssGSEA and CEMITool analysis in an independent HER2-amplified breast cancer cohort. Our findings suggest a wide range of biological functions for lncRNAs in each breast cancer molecular subtype and provide a basis for their biological and functional study, as was conducted for AC009283.1, showing it to be a potential regulator of proliferation and apoptosis in the HER2-enriched subtype.

Expression of long non-coding RNA ENSG00000226738 (LncKLHDC7B) is enriched in the immunomodulatory triple-negative breast cancer subtype and its alteration promotes cell migration, invasion, and resistance to cell death.

Triple negative breast cancer (TNBC) represents an aggressive phenotype with poor prognosis compared with ER, PR, and HER2-positive tumors. TNBC is a heterogeneous disease, and gene expression analysis has identified seven molecular subtypes. Accumulating evidence demonstrates that long non-coding RNA (lncRNA) are involved in regulation of gene expression and cancer biology, contributing to essential cancer cell functions. In this study, we analyzed the expression profile of lncRNA in TNBC subtypes from 156 TNBC samples, and then characterized the functional role of LncKLHDC7B (ENSG00000226738). A total of 710 lncRNA were found to be differentially expressed between TNBC subtypes, and a subset of these altered lncRNA were independently validated. We discovered that LncKLHDC7B (ENSG00000226738) acts as a transcriptional modulator of its neighboring coding gene KLHDC7B in the immunomodulatory subtype. Furthermore, LncKLHDC7B knockdown enhanced migration and invasion, and promoted resistance to cellular death. Our findings confirmed the contribution of LncKLHDC7B to induction of apoptosis and inhibition of cell migration and invasion, suggesting that TNBC tumors with enrichment of LncKLHDC7B may exhibit distinct regulatory activity, or that this may be a generalized process in breast cancer. Additionally, in silico analysis confirmed for the first time that the low expression of KLHDC7B and LncKLHDC7B is associated with poor prognosis in patients with breast cancer.

[Epigenetic alterations in cervical cancer progression]. / Alteraciones epigenéticas en la progresión del cáncer cervicouterino.

Despite the use of the screening test, such as Papanicolaou, and the detection of human papillomavirus (HPV), cervical cancer remains as a public health problem in México and it is the second leading cause of death for malignant neoplasias among women. High-risk HPV infection is the main risk factor for the development of premalignant lesions and cervical cancer; however, HPV infection is not the only factor; there are various genetic and epigenetic alterations required for the development of neoplasias; some of them have been described and even in some cases they have been suggested as biomarkers for prognosis. However, in contrast with other cancer types, such as breast cancer, in cervical cancer the use of biomarkers has not been established for clinical applications. Unlike genetic alterations, epigenetic alterations are potentially reversible; in this sense, their characterization is important, since they have not only a potential use as biomarkers, but they also could represent new therapeutic targets for treatment of cervical cancer. This review describes some of the more common epigenetic alterations in cervical cancer and its potential use in routine clinical practice.

A pesar del empleo de los métodos de tamizaje como el Papanicolaou y la detección de virus del papiloma humano (VPH), el cáncer cervicouterino (CaCU) sigue siendo un problema de salud pública en México, ya que es la segunda causa de muerte por neoplasias malignas en mujeres. La infección por VPH de alto potencial oncogénico es el principal factor de riesgo para el desarrollo de lesiones precursoras y CaCU; sin embargo, no es suficiente, dado que se requiere de diversas alteraciones genéticas y epigenéticas para el desarrollo de la neoplasia y un gran número de ellas han sido descritas, incluso en algunos casos se ha sugerido su uso como biomarcadores en la progresión o predictivos de respuesta. A diferencia de lo que sucede con otros tipos de cáncer, como el de mama, en el CaCU no se ha establecido el uso de marcadores para su aplicación en la clínica. A diferencia de las alteraciones genéticas, las alteraciones epigenéticas son potencialmente reversibles y su caracterización no solo tiene potencial para el uso como biomarcadores, sino como blancos de nuevas terapias. En esta revisión se describen algunas de las alteraciones epigenéticas más características en el CaCU, con potencial uso para la clínica.