Role of Nuclear Non-Canonical Nucleic Acid Structures in Organismal Development and Adaptation to Stress Conditions

Thiadiazole-, selenadiazole- and triazole-fused anthraquinones as G-quadruplex targeting anticancer compounds

G-quadruplex (G4) ligands attract considerable attention as potential anticancer therapeutics. In this study we proposed an original scheme for synthesis of azole-fused anthraquinones and prepared a series of G4 ligands carrying amino- or guanidinoalkylamino side chains. The heterocyclic core and structure of the terminal groups strongly affect on binding to G4-forming oligonucleotides, cellular accumulation and antitumor potency of compounds. In particular, thiadiazole- and selenadiazole- but not triazole-based ligands inhibit the proliferation of tumor cells (e.g. K562 leukemia) and stabilize primarily telomeric and c-MYC G4s. Anthraselenadiazole derivative 11a showed a good affinity to c-MYC G4 in vitro and down-regulated expression of c-MYC oncogene in cellular conditions. Further studies revealed that anthraselenadiazole 11a provoked cell cycle arrest and apoptosis in a dose- and time-dependent manner inhibiting K562 cells growth. Taken together, this work gives a valuable example that the closely related heterocycles may cause a significant difference in biological properties of G4 ligands.

SUMOylation-triggered ALIX activation modulates extracellular vesicles circTLCD4-RWDD3 to promote lymphatic metastasis of non-small cell lung cancer

Lymph node (LN) metastasis is one of the predominant metastatic routes of non-small cell lung cancer (NSCLC) and is considered as a leading cause for the unsatisfactory prognosis of patients. Although lymphangiogenesis is well-recognized as a crucial process in mediating LN metastasis, the regulatory mechanism involving lymphangiogenesis and LN metastasis in NSCLC remains unclear. In this study, we employed high-throughput sequencing to identify a novel circular RNA (circRNA), circTLCD4-RWDD3, which was significantly upregulated in extracellular vesicles (EVs) from LN metastatic NSCLC and was positively associated with deteriorated OS and DFS of patients with NSCLC from multicenter clinical cohort. Downregulating the expression of EV-packaged circTLCD4-RWDD3 inhibited lymphangiogenesis and LN metastasis of NSCLC both in vitro and in vivo. Mechanically, circTLCD4-RWDD3 physically interacted with hnRNPA2B1 and mediated the SUMO2 modification at K108 residue of hnRNPA2B1 by upregulating UBC9. Subsequently, circTLCD4-RWDD3-induced SUMOylated hnRNPA2B1 was recognized by the SUMO interaction motif (SIM) of ALIX and activated ALIX to recruit ESCRT-III, thereby facilitating the sorting of circTLCD4-RWDD3 into NSCLC cell-derived EVs. Moreover, EV-packaged circTLCD4-RWDD3 was internalized by lymphatic endothelial cells to activate the transcription of PROX1, resulting in the lymphangiogenesis and LN metastasis of NSCLC. Importantly, blocking EV-mediated transmission of circTLCD4-RWDD3 via mutating SIM in ALIX or K108 residue of hnRNPA2B1 inhibited the lymphangiogenesis and LN metastasis of NSCLC in vivo. Our findings reveal a precise mechanism underlying SUMOylated hnRNPA2B1-induced EV packaging of circTLCD4-RWDD3 in facilitating LN metastasis of NSCLC, suggesting that EV-packaged circTLCD4-RWDD3 could be a potential therapeutic target against LN metastatic NSCLC.

The Role of Methylation of a Group of microRNA Genes in the Pathogenesis of Metastatic Renal Cell Carcinoma

The role of methylation of 9 miRNA genes in the pathogenesis of metastatic clear cell renal cell carcinoma was determined by quantitative methylation-specific PCR (MS-PCR). For 5 genes (MIR125B-1, MIR137, MIR193A, MIR34B/C, and MIR375), a significant correlation of high methylation level with late (III-IV) stages, large size (T3+T4) of the tumor, and metastasis to lymph nodes and/or distant organs was revealed. For another group of genes (MIR125B-1, MIR1258, MIR193A, MIR34B/C, and MIR375), a statistically significant correlation of high methylation level with loss of differentiation in the tumor (G3-G4) was found, and the opposite pattern was found for MIR203A. A total of 7 microRNA genes (MIR125B-1, MIR1258, MIR137, MIR193A, MIR203A, MIR34B/C, and MIR375) were identified, the methylation of which is associated with the progression of metastatic clear cell renal cell carcinoma. For 6 of them (except MIR34B/C) these data were obtained for the first time. Thus, new factors of the development and progression of clear cell renal cell carcinoma were identified as potential biomarkers for the early diagnosis and prognosis of metastatic clear cell renal cell carcinoma.

LINC01137/miR-186-5p/WWOX: a novel axis identified from WWOX-related RNA interactome in bladder cancer

Introduction: The discovery of non-coding RNA (ncRNA) dates back to the pre-genomics era, but the progress in this field is still dynamic and leverages current post-genomics solutions. WWOX is a global gene expression modulator that is scarcely investigated for its role in regulating cancer-related ncRNAs. In bladder cancer (BLCA), the link between WWOX and ncRNA remains unexplored. The description of AP-2α and AP-2γ transcription factors, known as WWOX-interacting proteins, is more commonplace regarding ncRNA but still merits investigation. Therefore, this in vitro and in silico study aimed to construct an ncRNA-containing network with WWOX/AP-2 and to investigate the most relevant observation in the context of BLCA cell lines and patients. Methods: RT-112, HT-1376, and CAL-29 cell lines were subjected to two stable lentiviral transductions. High-throughput sequencing of cellular variants (deposited in the Gene Expression Omnibus database under the GSE193659 record) enabled the investigation of WWOX/AP-2-dependent differences using various bioinformatics tools (e.g., limma-voom, FactoMineR, multiple Support Vector Machine Recursive Feature Elimination (mSVM-RFE), miRDB, Arena-Idb, ncFANs, RNAhybrid, TargetScan, Protein Annotation Through Evolutionary Relationships (PANTHER), Gene Transcription Regulation Database (GTRD), or Evaluate Cutpoints) and repositories such as The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia. The most relevant observations from cap analysis gene expression sequencing (CAGE-seq) were confirmed using real-time PCR, whereas TCGA data were validated using the GSE31684 cohort. Results: The first stage of the whole study justified focusing solely on WWOX rather than on WWOX combined with AP-2α/γ. The most relevant observation of the developed ncRNA-containing network was LINC01137, i.e., long non-coding RNAs (lncRNAs) that unraveled the core network containing UPF1, ZC3H12A, LINC01137, WWOX, and miR-186-5p, the last three being a novel lncRNA/miRNA/mRNA axis. Patients' data confirmed the LINC01137/miR-186-5p/WWOX relationship and provided a set of dependent genes (i.e., KRT18, HES1, VCP, FTH1, IFITM3, RAB34, and CLU). Together with the core network, the gene set was subjected to survival analysis for both TCGA-BLCA and GSE31684 patients, which indicated that the increased expression of WWOX or LINC01137 is favorable, similar to their combination with each other (WWOX↑ and LINC01137↑) or with MIR186 (WWOX↑/LINC01137↑ but MIR186↓). Conclusion: WWOX is implicated in the positive feedback loop with LINC01137 that sponges WWOX-targeting miR-186-5p. This novel WWOX-containing lncRNA/miRNA/mRNA axis should be further investigated to depict its relationships in a broader context, which could contribute to BLCA research and treatment.