An Overview of the Role of Long Non-Coding RNAs in Human Choriocarcinoma

Current status of in vitro models for rare gynaecological cancer research

Gynaecological cancers originate within the female reproductive system and are classified according to the site in the reproductive system where they arise. However, over 50 % of these malignancies are categorized as rare, encompassing 30 distinct histological subtypes, which complicates their diagnosis and treatment. The focus of this review is to give an overview of established in vitro models for the investigation of rare gynaecological cancers, as well as an overview of available online databases that contain detailed descriptions of cell line characteristics. Cell lines represent the main models for the research of carcinogenesis, drug resistance, pharmacodynamics and novel therapy treatment options. Nowadays, classic 2D cell models are increasingly being replaced with 3D cell models, such as spheroids, organoids, and tumoroids because they provide a more accurate representation of numerous tumour characteristics, and their response to therapy differs from the response of adherent cell lines. It is crucial to use the correct cell line model, as rare tumour types can show characteristics that differ from the most common tumour types and can therefore respond unexpectedly to classic treatment. Additionally, some cell lines have been misclassified or misidentified, which could lead to false results. Even though rare gynaecological cancers are rare, this review will demonstrate that there are available options for investigation of such cancers in vitro on biologically relevant models.

Transcriptome analysis provides critical answers to the "variants of uncertain significance" conundrum

While whole-genome and exome sequencing have transformed our collective understanding of genetics' role in disease pathogenesis, there are certain conditions and populations for whom DNA-level data fails to identify the underlying genetic etiology. Specifically, patients of non-White race and non-European ancestry are disproportionately affected by "variants of unknown/uncertain significance" (VUS), limiting the scope of precision medicine for minority patients and perpetuating health disparities. VUS often include deep intronic and splicing variants which are difficult to interpret from DNA data alone. RNA analysis can illuminate the consequences of VUS, thereby allowing for their reclassification as pathogenic versus benign. Here we review the critical role transcriptome analysis plays in clarifying VUS in both neoplastic and non-neoplastic diseases.

METTL3 m6A-dependently promotes miR-21-5p maturation to accelerate choriocarcinoma progression via the HIF1AN-induced inactivation of the HIF1A/VEGF pathway

BACKGROUND

Gestational choriocarcinoma is a highly malignant neoplastic disease derived from pathological changes in trophoblastic cells. Recent evidences have shown that N6-methyladenosine (m6A) modifications play important role in modulating the development of multiple cancers, but the detailed mechanisms by which m6A-mediated choriocarcinoma progression have not been fully delineated.

OBJECTIVES

This study aimed to investigate the role of m6A in choriocarcinoma and reveal its underlying molecular mechanisms.

METHODS

The expression of METTL3, miR-21-5p and HIF1AN was detected using RT-qPCR in tissues and cells. The protein expression of METTL3, HIF1AN, HIF1A and VEGF were measured by western blot. The luciferase reporter assays and RNA immunoprecipitation (RIP) were used to verify the relationship between miR-21-5p and HIF1AN. The CCK-8, colony formation and transwell assays were used to detected cell proliferation and cell migration, respectively.

RESULTS

Here, we demonstrated that the m6A methyltransferase-like 3 (METTL3) was aberrantly high-expressed in the clinical choriocarcinoma tissues and choriocarcinoma cell lines compared to the corresponding normal counterparts. The following functional experiments verified that silencing of METTL3 suppressed cell proliferation, migration, epithelial-mesenchymal transition (EMT) and tumorigenesis in vitro and in vivo to hamper the aggressiveness of choriocarcinoma. Next, the mechanical experiments confirmed that METTL3 promoted the maturation of miR-21-5p in an m6A-dependent manner, and elevated miR-21-5p subsequently degraded its downstream hypoxia-inducible factor asparagine hydroxylase (HIF1AN) by targeting its 3' untranslated regions (3'-UTR), resulting in the activation of the tumor-promoting HIF1A/VEGF pathway. Finally, the rescuing experiments verified that METTL3 ablation-induced inhibitory effects on the malignant phenotypes in choriocarcinoma were all abrogated by both miR-21-5p overexpression and HIF1AN downregulation.

CONCLUSIONS

Collectively, this study firstly reported the involvement of the METTL3/m6A/miR-21-5p/HIF1AN signaling cascade in regulating the progression of choriocarcinoma, which provided novel biomarkers for the diagnosis and treatment of this disease.

The Regulatory Functions and the Mechanisms of Long Non-Coding RNAs in Cervical Cancer

Cervical cancer is one of the leading causes of death in gynecology cancer worldwide. High-risk human papillomaviruses (HPVs) are the major etiological agents for cervical cancer. Still, other factors also contribute to cervical cancer development because these cancers commonly arise decades after initial exposure to HPV. So far, the molecular mechanisms underlying the pathogenesis of cervical cancer are still quite limited, and a knowledge gap needs to be filled to help develop novel strategies that will ultimately facilitate the development of therapies and improve cervical cancer patient outcomes. Long non-coding RNAs (lncRNAs) have been increasingly shown to be involved in gene regulation, and the relevant role of lncRNAs in cervical cancer has recently been investigated. In this review, we summarize the recent progress in ascertaining the biological functions of lncRNAs in cervical cancer from the perspective of cervical cancer proliferation, invasion, and metastasis. In addition, we provide the current state of knowledge by discussing the molecular mechanisms underlying the regulation and emerging role of lncRNAs in the pathogenesis of cervical cancer. Comprehensive and deeper insights into lncRNA-mediated alterations and interactions in cellular events will help develop novel strategies to treat patients with cervical cancer.

The mechanism underlying arsenic-induced PD-L1 upregulation in transformed BEAS-2B cells

Chronic exposure to arsenic promotes lung cancer. Human studies have identified immunosuppression as a risk factor for cancer development. The immune checkpoint pathway of Programmed cell death 1 ligand (PD-L1) and its receptor (programmed cell death receptor 1, PD-1) is the most studied mechanism of immunosuppression. We have previously shown that prolonged arsenic exposure induced cell transformation of BEAS-2B cells, a human lung epithelial cell line. More recently our study further showed that arsenic induced PD-L1 up-regulation, inhibited T cell effector function, and enhanced lung tumor formation in the mice. In the current study, using arsenic-induced BEAS-2B transformation as a model system we investigated the mechanism underlying PD-L1 up-regulation by arsenic. Our data suggests that Lnc-DC, a long non-coding RNA, and signal transducer and activator of transcription 3 (STAT3) mediates PD-L1 up-regulation by arsenic.

The Role of Long Non-Coding RNAs (lncRNAs) in Female Oriented Cancers

Recent advances in molecular biology have discovered the mysterious role of long non-coding RNAs (lncRNAs) as potential biomarkers for cancer diagnosis and targets for advanced cancer therapy. Studies have shown that lncRNAs take part in the incidence and development of cancers in humans. However, previously they were considered as mere RNA noise or transcription byproducts lacking any biological function. In this article, we present a summary of the progress on ascertaining the biological functions of five lncRNAs (HOTAIR, NEAT1, H19, MALAT1, and MEG3) in female-oriented cancers, including breast and gynecological cancers, with the perspective of carcinogenesis, cancer proliferation, and metastasis. We provide the current state of knowledge from the past five years of the literature to discuss the clinical importance of such lncRNAs as therapeutic targets or early diagnostic biomarkers. We reviewed the consequences, either oncogenic or tumor-suppressing features, of their aberrant expression in female-oriented cancers. We tried to explain the established mechanism by which they regulate cancer proliferation and metastasis by competing with miRNAs and other mechanisms involved via regulating genes and signaling pathways. In addition, we revealed the association between stated lncRNAs and chemo-resistance or radio-resistance and their potential clinical applications and future perspectives.