Upregulation of pluripotent long noncoding RNA ES3 in HER2-positive breast cancer

LncRNA PNKY Is Upregulated in Breast Cancer and Promotes Cell Proliferation and EMT in Breast Cancer Cells

Long non-coding RNAs (lncRNAs) are known to be important regulators in different cellular processes and are implicated in various human diseases. Recently, lncRNA PNKY has been found to be involved in pluripotency and differentiation of embryonic and postnatal neural stem cells (NSCs); however, its expression and function in cancer cells is still unclear. In the present study, we observed the expression of PNKY in various cancer tissues, including brain, breast, colorectal, and prostate cancers. In particular, we demonstrated that lncRNA PNKY was significantly upregulated in breast tumors, especially high-grade tumors. Knock down experiments indicated that the suppression of PNKY in breast cancer cells could restrict their proliferation by promoting apoptosis, senescence, and cell cycle disruption. Moreover, the results demonstrated that PNKY may play a crucial role in the cell migration of breast cancer cells. We further found that PNKY may trigger EMT in breast cancer cells by upregulating miR-150 and restricting the expression of Zeb1 and Snail. This study is the first to provide new evidence on the expression and biological function of PNKY in cancer cells and its potential contribution to tumor growth and metastasis.

Coding roles of long non-coding RNAs in breast cancer: Emerging molecular diagnostic biomarkers and potential therapeutic targets with special reference to chemotherapy resistance

Dysregulation of epigenetic mechanisms have been depicted in several pathological consequence such as cancer. Different modes of epigenetic regulation (DNA methylation (hypomethylation or hypermethylation of promotor), histone modifications, abnormal expression of microRNAs (miRNAs), long non-coding RNAs, and small nucleolar RNAs), are discovered. Particularly, lncRNAs are known to exert pivot roles in different types of cancer including breast cancer. LncRNAs with oncogenic and tumour suppressive potential are reported. Differentially expressed lncRNAs contribute a remarkable role in the development of primary and acquired resistance for radiotherapy, endocrine therapy, immunotherapy, and targeted therapy. A wide range of molecular subtype specific lncRNAs have been assessed in breast cancer research. A number of studies have also shown that lncRNAs may be clinically used as non-invasive diagnostic biomarkers for early detection of breast cancer. Such molecular biomarkers have also been found in cancer stem cells of breast tumours. The objectives of the present review are to summarize the important roles of oncogenic and tumour suppressive lncRNAs for the early diagnosis of breast cancer, metastatic potential, and chemotherapy resistance across the molecular subtypes.

Exosomal lncRNA FOXD3-AS1 upregulates ELAVL1 expression and activates PI3K/Akt pathway to enhance lung cancer cell proliferation, invasion, and 5-fluorouracil resistance

Long non-coding RNA (lncRNA) FOXD3-AS1 expression is upregulated in lung cancer; however, its effect and mechanism on 5-fluorouracil (5-FU) resistance remain unclear. In this study, we determined the effects of FOXD3-AS1-enriched exosomes derived from lung cancer cells on the proliferation, invasion, and 5-FU resistance of lung cancer cells. Online bioinformatics database analysis showed that FOXD3-AS1 was upregulated in lung cancer progression. Real-time quantitative PCR results confirmed that FOXD3-AS1 expression was upregulated in lung cancer tissues and cell lines, and FOXD3-AS1 was greatly enriched in lung cancer cell-derived exosomes. ELAV-like RNA-binding protein 1 (ELAVL1) was identified as an RNA-binding protein of FOXD3-AS1. The lung cancer cell-derived exosomes promoted A549 cell proliferation and invasion and inhibited apoptosis caused by 5-FU, and transfection of si-FOXD3-AS1 or si-ELAVL1 in exosome-incubated A549 cells reversed these effects. Moreover, exosome-incubated A549 cells were co-transfected with si-FOXD3-AS1 and pcDNA-ELAVL1, showing the same cell proliferation, invasion, and 5-FU resistance as those of A549 cells treated with lung cancer cell-derived exosomes alone. Mechanistic studies identified that lung cancer cell-derived exosomes activated the PI3K/Akt pathway, and transfection of si-FOXD3-AS1 or treatment with the PI3K inhibitor LY294002 reversed the activation of the PI3K/Akt axis induced by exosomes. In conclusion, our study revealed that lung cancer cell-derived exosomal FOXD3-AS1 upregulated ELAVL1 expression and activated the PI3K/Akt pathway to promote lung cancer progression. Our findings provide a new strategy for lung cancer treatment.

Long non-coding RNA-based signatures to improve prognostic prediction of breast cancer

Breast cancer (BC) is a disease of high mortality rate because of high malignant, while early diagnosis and personal management may make a better prognosis possible. This study aimed to establish and validate lncRNAs signatures to improve the prognostic prediction for BC.RNA sequencing data along with the corresponding clinical information of patients with BC were gained from The Cancer Genome Atlas (TCGA). Prognostic differentially expressed lncRNAs were obtained using differentially expressed lncRNAs analysis (P value <.01 and |fold change| > 2) and univariate cox regression (P value <.05). By applying least absolute shrinkage and selection operation (LASSO) Cox regression analysis along with 10-fold cross-validation, 2 lncRNA-based signatures were constructed in the training, test and whole set.A 14-lncRNAs signature and a 10-lncRNAs signature were built for overall survival (OS) and relapse-free survival (RFS) respectively in the 3 sets. BC patients were divided into high-risk groups and low-risk groups depended on median risk score value. Significant differences were found for OS and RFS between 2 groups in the 3 sets. The time-dependent receiver operating characteristic (ROC) curves analysis demonstrated that our lncRNAs signatures had better predictive capacities of survival and recurrence for BC patients as well as enhancing the predictive ability of the tumor node metastasis (TNM) stage system.These results indicate that the 2 lncRNAs signatures with the potential to be biomarkers to predict the prognosis of BC for OS and RFS.

Long noncoding RNAs and exosomal lncRNAs: classification, and mechanisms in breast cancer metastasis and drug resistance

Breast cancer is the most common cancer, and the second cause of cancer-related deaths (after lung cancer) among women. Developing tumor metastasis and invasion is the most important cause of death in breast cancer patients. Several key factors participate in breast cancer metastasis including long noncoding RNAs (lncRNAs). lncRNAs are a category of cellular RNAs that are longer than 200 nucleotides in length. Accumulating evidence suggests that lncRNAs have the potential to be promising diagnostic, prognostic biomarkers and therapeutic targets in breast cancer. Understanding the role of lncRNAs and their mechanisms of functions might help to further discovery of breast cancer biological characteristics. In this review, we discuss physiological functions, epigenetic regulation, transcriptional regulation of lncRNAs, and their important role in tumor progression and metastasis. Some lncRNAs function as oncogenes and some function as tumor suppressors. Interestingly, recent reports depict that hypomethylation of promoters of lncRNAs play a pivotal role in cancer progression, suggesting the importance of epigenetic regulation. Furthermore, we discuss the role of lncRNAs in exosomes and their function in drug resistance, and therapeutic importance of exosomal lncRNAs in cancer biology. In summary, lncRNAs have a great potential to consider them as novel prognostic biomarkers as well as new therapeutic targets in breast cancer.