Yan Lu

CircMETTL6 Suppresses Ovarian Cancer Cell Growth and Metastasis Through Inhibition of GDF15 Transcription by Disrupting the NONO‐POLR2A Complex

AbstractCircular RNAs (circRNAs) are a distinctive class of non‐coding RNAs with covalent closed‐loop structure, lacking 5′ caps and 3′ poly(A) tails. These molecules are prevalent in eukaryotes and play key roles in cancer. Here, the function of a new circRNA, circMETTL6, in ovarian cancer is identified and investigated. The prognostic significance of circMETTL6 is assessed using RNA in situ hybridization. Functional studies involving circMETTL6 overexpression are performed both in vitro and in vivo. Mechanistic investigations are performed using RNA‐seq, RNA pull‐down, RNA immunoprecipitation, co‐immunoprecipitation, chromatin immunoprecipitation, protein degradation assay and dual‐luciferase reporter assays. circMETTL6 is significantly downregulated in ovarian cancer, and its lower expression correlates with worse prognosis. Overexpression of circMETTL6 significantly inhibited proliferation, migration, and invasion of ovarian cancer cell in vitro, as well as tumor growth and metastasis in vivo. Mechanistically, circMETTL6 recruited the non‐POU domain containing octamer binding protein (NONO) by binding to its Coiled‐coil domain and disrupted its binding with RNA polymerase II subunit A (POLR2A), and consequently inhibiting growth differentiation factor 15 (GDF15) transcription, thereby suppressing ovarian cancer progression. These findings establish circMETTL6 as a novel tumor suppressor in ovarian cancer. Targeting the circMETTL6/NONO/GDF15 axis presents a potential therapeutic avenue for ovarian cancer treatment.

Triple signal amplification strategy for the ultrasensitive electrochemical detection of human papillomavirus 16 E6/E7 mRNA

Human papilloma virus (HPV) is the primary causative agent of cervical, vaginal, and vulvar cancers. HPV E6/E7 mRNA detection has been proven to improve the specificity and positive predictive value compared with HPV DNA testing in screening, whereby, it may possess higher diagnostic potential. Herein, to establish the ultrasensitive and specific detection of HPV E6/E7 mRNA, we developed a novel triple signal amplification strategy, combined with gold nanoparticles (AuNPs), reverse transcription loop-mediated isothermal amplification (RT-LAMP) and high affinity biotin-avidin system. This novel proposed signal amplification strategy exhibits the desired detection limit of 0.08 fM (approximately 100 copies) and a wide linear range from 0.1 pmol/mL to 100 nmol/mL for HPV16 E6/E7 mRNA detection. Importantly, the present novel biosensor is 10-100 times more sensitive than conventional RT-PCR in detecting HPV16 E6/E7 mRNA positive clinical samples. Conclusively, this biosensor shows good stability, selectivity, and reproducibility, which demonstrates its potential in future clinical diagnosis with desirable sensitivity and specificity.

LncRNA SFTA1P promotes cervical cancer progression by interaction with PTBP1 to facilitate TPM4 mRNA degradation

AbstractLong non-coding RNAs (lncRNAs) play key roles in cancer development and progression. However, the biological function and clinical significance of most lncRNAs in cervical cancer remain elusive. In this study, we explore the function and mechanism of lncRNA surfactant associated 1 (SFTA1P) in cervical cancer. We firstly identified SFTA1P by analyzing the RNA sequencing data of cervical cancer from our previous study and from The Cancer Genome Atlas (TCGA). We then verified SFTA1P expression by qRT-PCR. The cell proliferation and migration capacity of SFTA1P was assessed by using CCK-8, colony formation, transwell and wound healing assays. RNA pull-down, RNA immunoprecipitation (RIP), RNA stability and western blot assays were used to reveal potential mechanisms. Athymic nude mice were used to evaluate tumorigenicity and metastasis in vivo. SFTA1P is upregulated in cervical tumor tissues and its high expression is associated with poor prognosis. Biologically, knockdown of SFTA1P inhibited the proliferation, migration, and invasion of cervical cancer cells in vitro, as well as tumorigenesis and metastasis in vivo. Mechanistically, SFTA1P was shown to interact with polypyrimidine tract binding protein 1 (PTBP1) to regulate the stability of tropomyosin 4 (TPM4) mRNA, thereby resulting in malignant cell phenotypes. TPM4 knockdown could attenuate the suppression of cell progression induced by either SFTA1P or PTBP1 knockdown. Our findings demonstrate that SFTA1P can promote tumor progression by mediating the degradation of TPM4 mRNA through its interaction with PTBP1 protein. This provides a potential therapeutic strategy to target the SFTA1P-PTBP1-TPM4 axis in cervical cancer.

Long-read sequencing unveils high-resolution HPV integration and its oncogenic progression in cervical cancer

AbstractIntegration of human papillomavirus (HPV) DNA into the human genome is considered as a key event in cervical carcinogenesis. Here, we perform comprehensive characterization of large-range virus-human integration events in 16 HPV16-positive cervical tumors using the Nanopore long-read sequencing technology. Four distinct integration types characterized by the integrated HPV DNA segments are identified with Type B being particularly notable as lacking E6/E7 genes. We further demonstrate that multiple clonal integration events are involved in the use of shared breakpoints, the induction of inter-chromosomal translocations and the formation of extrachromosomal circular virus-human hybrid structures. Combined with the corresponding RNA-seq data, we highlight LINC00290, LINC02500 and LENG9 as potential driver genes in cervical cancer. Finally, we reveal the spatial relationship of HPV integration and its various structural variations as well as their functional consequences in cervical cancer. These findings provide insight into HPV integration and its oncogenic progression in cervical cancer.