ABSTRACT
BACKGROUND: Long intergenic non-protein coding RNA 707 (LINC00707) has been identified as a cancer-associated long non-coding RNA (lncRNA) in a variety of cancers. However, the functions and molecular mechanisms of LINC00707 in esophageal squamous cell carcinoma (ESCC) are still unclear. METHODS: The expression of LINC00707 in esophageal cancer (ESCA) and ESCC tissues was determined by online tools, RNA-sequence (RNA-seq) dataset, and quantitative real time polymerase chain reaction (qRT-PCR). The associations between LINC00707 expression and clinicopathologic features and prognosis were investigated. Furthermore, the expression of LINC00707 in ESCC cell lines was determined by qRT-PCR. Then, using LncACTdb 2.0 database, combined with loss-of-function assay verification, we investigated the biologic role of LINC00707 in ESCC cell growth, apoptosis, invasion, and migration by CCK-8, colony formation, flow cytometry and transwell assays. Finally, western blot was used to evaluate the regulatory effect of LINC00707 on PI3K/Akt signaling pathway. RESULTS: Increased LINC00707 expression was exhibited in ESCC tissues and cell lines. High expression of LINC00707 was positively associated with higher tumor-node-metastasis (TNM) stage and lymph node metastasis. Furthermore, LINC00707 expression was significantly higher in patients who drink alcohol, have lymph node metastasis, and harbor higher tumor stage. In addition, Kaplan-Meier survival analysis and receiver operating characteristic (ROC) curve confirmed the feasibility of LINC00707 as a prognostic signature or diagnostic marker. Functional experiments showed that LINC00707 downregulation suppressed ESCC cell proliferation, and metastasis, and induced ESCC cell apoptosis. Mechanistic investigation demonstrated that LINC00707 activated the PI3K/Akt signaling pathway in ESCC cells. CONCLUSIONS: Our findings suggest LINC00707 functions as an oncogenic lncRNA in ESCC, and imply that LINC00707 may be a promising prognostic biomarker and therapeutic target for ESCC patients.
ABSTRACT
Chemoresistance is an impending challenge in cancer treatment. In recent years, exosomes, a subtype of extracellular vesicles with a diameter of 40-150 nm in bloodstream and other bio-fluids, have attracted increasing interest. Exosomes contain proteins, nucleic acids, and lipids, which act as important signaling molecules. Many reports indicate that exosomes play critical roles in chemoresistance through intercellular interactions, including drug removal from cells, transfer of drug resistance phenotypes to other cancer cells, and the increase in plastic stem cell subsets. Exosomes can reflect the physiological and pathological state of parent cells. Owing to their elevated stability, specificity, and sensitivity, exosomes are served as biomarkers in liquid biopsies to monitor cancer chemoresistance, progression, and recurrence. This review summarizes the exosome-mediated mechanisms of cancer chemoresistance, as well as its role in reversing and monitoring chemoresistance. The scientific and technological challenges and future applications of exosomes are also explored.
ABSTRACT
Prostate cancer (PCa) is the most common solid tumor in men. While patients with local PCa have better prognostic survival, patients with metastatic PCa have relatively high mortality rates. Existing diagnostic methods for PCa rely on tissue biopsy and blood prostate-specific antigen (PSA) detection; however, the PSA test does not detect aggressive PCa. Liquid biopsy is a promising technique to overcome tumor heterogeneity in diagnosis, provide more comprehensive information, and track tumor progression over time, allowing for the development of treatment options at all stages of PCa. Exosomes containing proteins and nucleic acids are potential sources of tumor biomarkers. Accumulating evidence indicates that exosomes play important roles in cell communication and tumor progression and are suitable for monitoring PCa progression and metastasis. In this review, we summarize recent advances in the use of exosomal proteins and miRNAs as biomarkers for monitoring PCa invasion and metastasis and discuss their feasibility in clinical diagnosis.
ABSTRACT
The development and application of whole genome sequencing technology has greatly broadened our horizons on the capabilities of long non-coding RNAs (lncRNAs). LncRNAs are more than 200 nucleotides in length and lack protein-coding potential. Increasing evidence indicates that lncRNAs exert an irreplaceable role in tumor initiation, progression, as well as metastasis, and are novel molecular biomarkers for diagnosis and prognosis of cancer patients. Furthermore, lncRNAs and the pathways they influence might represent promising therapeutic targets for a number of tumors. Here, we discuss the recent advances in understanding of the specific regulatory mechanisms of lncRNAs. We focused on the signal, decoy, guide, and scaffold functions of lncRNAs at the epigenetic, transcription, and post-transcription levels in cancer cells. Additionally, we summarize the research strategies used to investigate the roles of lncRNAs in tumors, including lncRNAs screening, lncRNAs characteristic analyses, functional studies, and molecular mechanisms of lncRNAs. This review will provide a short but comprehensive description of the lncRNA functions in tumor development and progression, thus accelerating the clinical implementation of lncRNAs as tumor biomarkers and therapeutic targets.
