Distinct from classical tumor angiogenesis, vasculogenic mimicry (VM) provides a blood supply for tumor cells independent of endothelial cells. VM has two distinct types, namely tubular type and patterned matrix type. VM is associated with high tumor grade, tumor progression, invasion, metastasis, and poor prognosis in patients with malignant tumors. Herein, we discuss the recent studies on the role of VM in tumor progression and the diverse mechanisms and signaling pathways that regulate VM in tumors. Furthermore, we also summarize the latest findings of non-coding RNAs, such as lncRNAs and miRNAs in VM formation. In addition, we review application of molecular imaging technologies in detection of VM in malignant tumors. Increasing evidence suggests that VM is significantly associated with poor overall survival in patients with malignant tumors and could be a potential therapeutic target.

Circular RNAs (circRNAs) are a class of endogendous RNAs that form a covalently closed continuous loop and exist extensively in mammalian cells. Majority of circRNAs are conserved across species and often show tissue/developmental stage-specific expression. CircRNAs were first thought to be the result of splicing error; however, subsequent research shows that circRNAs can function as microRNA (miRNA) sponges and regulate splicing and transcription. Emerging evidence shows that circRNAs possess closely associated with human diseases, especially cancers, and may serve as better biomarkers. After miRNA and long noncoding RNA (lncRNA), circRNAs are becoming a new hotspot in the field of RNA of cancer. Here, we review biogenesis and metabolism of circRNAs, their functions, and potential roles in cancer.

Vasculogenic mimicry (VM) gives rise to tumor neovascularization that is critical for tumor growth and metastasis. Long non-coding RNAs (lncRNAs) have been implicated in diverse and fundamental biological processes. LINC00312 is associated with lung adenocarcinoma. In this study, we found that LINC00312 induced migration, invasion and VM of lung cancer cells by direct binding to the transcription factor Y-Box Binding Protein 1 (YBX1). Moreover, we demonstrated that YBX1 is associated with different fragments within 0–2410 nt 5’region of LINC00312. In addition, LINC00312 is associated with VM in 124 lung adenocarcinoma clinical specimens. The results suggest that LINC00312 is a promising therapeutic and diagnostic target for lung adenocarcinoma.

MicroRNAs are small noncoding RNAs that modulate a variety of cellular processes by regulating multiple targets, which can promote or inhibit the development of malignant behaviors. Accumulating evidence suggests that miR-675-5p plays important roles in human carcinogenesis. However, its precise biological role remains largely elusive. This study examined the role of miR-675-5p in non- small cell lung cancer (NSCLC). The expression of miR-675-5p was analyzed by real-time quantitative PCR (qRT-PCR). The effect of miR-675-5p on proliferation was evaluated through MTT and colony formation assays, and cell migration and invasion were evaluated through transwell assays. The expression of target proteins and downstream molecules was analyzed by western blotting and immunohistochemical staining. The luciferase reporter assay was used to assess the target genes of miR-675-5p in non-small cell lung cancer cells. The expression levels of miR-675-5p in NSCLC tissues were significantly reduced compared to those in adjacent non-cancerous tissues (P < 0.001). The expression of miR-675-5p in patients with non-small cell lung cancer had a negative correlation with lymph node metastasis (P < 0.01) and TNM stage (P < 0.05). Down-regulation of miR-675-5p promoted cell growth, proliferation, colony formation, invasion and migration, and promoted the tumorigenicity graft growth of nude mice in vivo (P < 0.01); whereas up-regulation of miR-675-5p had the contrary effects. The luciferase reporter assay showed that GPR55 was a direct target gene of miR-675-5p. Overexpression of miR-675-5p can lead to the down-regulation of GPR55 and its signaling pathway, whereas the effect can be reversed by down-regulation of miR-675-5p expression. miR-675-5p functions as a novel tumor suppressor in NSCLC and the anti-oncogenic activity may involve its inhibition of the target gene GPR55. These findings suggest the possibility for miR-675-5p as a therapeutic target in NSCLC.

TRNA is one of the most conserved and abundant RNA species, which plays a key role during protein translation. tRNA molecules are post-transcriptionally modified by tRNA modifying enzymes. Since high-throughput sequencing technology has developed rapidly, tRNA modification types have been discovered in many research fields. In tRNA, numerous types of tRNA modifications and modifying enzymes have been implicated in biological functions and human diseases. In our review, we talk about the relevant biological functions of tRNA modifications, including tRNA stability, protein translation, cell cycle, oxidative stress, and immunity. We also explore how tRNA modifications contribute to the progression of human diseases. Based on previous studies, we discuss some emerging techniques for assessing tRNA modifications to aid in discovering different types of tRNA modifications.

The receptor for advanced glycation end products (RAGE) is oncogenic and overexpressed in human cancers, but its role in hepatocellular carcinoma remains unclear. Here we demonstrated that RAGE is overexpressed in primary hepatocellular carcinoma (PHC) compared to adjacent para-neoplastic liver samples. Serum endogenous secretory RAGE levels were also increased in PHC patients (p < 0.01). Moreover, we demonstrated that RAGE regulates cellular proliferation in Hepatocellular carcinoma (HCC). Knockdown of RAGE by specific siRNA inhibited cellular growth in the hepatocellular carcinoma cell line, Huh7, whereas the RAGE ligand, high mobility group box 1 protein (HMGB1) increased cellular proliferation. In addition, knockdown of RAGE by siRNA arrested cells in the G1 phase and inhibited DNA synthesis (p < 0.01), while HMGB1 protein decreased the number of cells in the G1 phase and increased the number in the S phase (p < 0.05). Furthermore, quantitative real time RT-PCR (qRT-PCR) and Western Blot results demonstrated that RAGE and HMGB1 positively regulate NF-κB p65 expression in Huh7 cells. These studies suggest that RAGE and RAGE ligands are important targets for therapeutic intervention in hepatocellular carcinoma.