The Significance of Long Non-coding RNA HULC in Predicting Prognosis and Metastasis of Cancers: a Meta-Analysis

The Role of Long Non-Coding RNAs in Modulating the Immune Microenvironment of Triple-Negative Breast Cancer: Mechanistic Insights and Therapeutic Potential

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive subtype of breast cancer that faces therapeutic challenges due to a shortage of effective targeted therapies. The complex biology of TNBC renders its clinical management fraught with difficulties, especially regarding the immune microenvironment of the tumor. In recent years, long non-coding RNAs (lncRNAs) have been recognized as important gene regulators with key roles in tumor development and microenvironmental regulation. Previous studies have shown that lncRNAs play important roles in the immune microenvironment of TNBC, including the regulation of tumor immune escape and the function of tumor-infiltrating immune cells. However, despite the increasing research on lncRNAs, there are still many unanswered questions, such as their specific mechanism of action and how to effectively utilize them as therapeutic targets. Therefore, the aim of this study was to review the mechanisms of lncRNAs in the TNBC immune microenvironment, explore their regulatory roles in tumor immune escape and immune cell infiltration, and explore their prospects as potential therapeutic targets. By integrating the latest research results, this study aims to provide new ideas and directions for future TNBC treatment.

Qntrolling the LncRNA HULC-Tregs-PD-1 axis inhibits immune escape in the tumor microenvironment

Background

Immune escape remains a major challenge in the treatment of malignant tumors. Here, we studied the mechanisms underlying immune escape in the tumor microenvironment and identified a potential therapeutic target.

Methods

Pathological specimens from patients with liver cancer, soft tissue sarcoma, and liver metastasis of colon cancer were subjected to immunohistochemistry analysis to detect the expression of programmed death-1 (PD-1) in the tumor microenvironment (TME). Additionally, the expression of regulatory T cells (Tregs) and long non-coding RNAs (lncRNAs), such as highly upregulated in liver cancer (HULC) was evaluated by fluorescence in situ hybridization, and the relationship between HULC, Treg cells, and PD-1 was determined. The animals were divided into H22 hepatic carcinoma and S180 sarcoma groups. Each group was divided into Foxp3-/-C57BL/6J and C57BL/6J mice. Thereafter, mice were inoculated with 0.1 ml S180 sarcoma cells or 0.1 ml H22 hepatoma cells, at a concentration of 1 × 107/ml. The number of splenic CD4+CD25+Foxp3+ T cells was detected by flow cytometry, and serum interleukin-10 (IL-10) and transforming growth factor β1 (TGF-β1) levels were detected using a Luminex liquid suspension chip. Expression of PD-1, fork head box P3 (Foxp3), and HULC in the TME, were analyzed and the therapeutic effect of inhibiting the lncRNA HULC-Treg-PD-1 axis in malignant tumors was determined.

Results

High expression of lncRNA HULC promotes the proliferation of Treg cells and increases PD-1 expression in the tumor microenvironment. The HULC-Treg-PD-1 axis plays an immunosuppressive role and promotes the proliferation of malignant tumors. Knocking out the Foxp3 gene can affect the HULC-Treg-PD-1 axis and reduce PD-1, IL-10, and TGF-β1 expression to control the growth of malignant tumors.

Conclusion

The lncRNA HULC-Treg-PD-1 axis promotes the growth of malignant tumors. This axis could be modulated to reduce PD-1, IL-10, and TGF-β1 expression and the subsequent immune escape. The inhibition of immune escape in the tumor microenvironment can be achieved by controlling the LncRNA HULC-Treg-PD-1 axis.

The roles of lncRNAs and miRNAs in pancreatic cancer: a focus on cancer development and progression and their roles as potential biomarkers

Pancreatic ductal adenocarcinoma (PDAC) is among the most penetrative malignancies affecting humans, with mounting incidence prevalence worldwide. This cancer is usually not diagnosed in the early stages. There is also no effective therapy against PDAC, and most patients have chemo-resistance. The combination of these factors causes PDAC to have a poor prognosis, and often patients do not live longer than six months. Because of the failure of conventional therapies, the identification of key biomarkers is crucial in the early diagnosis, treatment, and prognosis of pancreatic cancer. 65% of the human genome encodes ncRNAs. There are different types of ncRNAs that are classified based on their sequence lengths and functions. They play a vital role in replication, transcription, translation, and epigenetic regulation. They also participate in some cellular processes, such as proliferation, differentiation, metabolism, and apoptosis. The roles of ncRNAs as tumor suppressors or oncogenes in the growth of tumors in a variety of tissues, including the pancreas, have been demonstrated in several studies. This study discusses the key roles of some lncRNAs and miRNAs in the growth and advancement of pancreatic carcinoma. Because they are involved not only in the premature identification, chemo-resistance and prognostication, also their roles as potential biomarkers for better management of PDAC patients.

LncRNA HULC as a potential predictor of prognosis and clinicopathological features in patients with digestive system tumors: a meta-analysis

Objective: This meta-analysis aimed to evaluate the correlation between lncRNA HULC, prognosis and clinicopathological characteristics in patients with digestive system tumors.

Methods: The relevant literatures were collected through PubMed, Web of Science and Embase up to February 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to assess the prognostic value of HULC in patients with digestive system tumors. The clinicopathological characteristics of HULC in patients were estimated by odds ratios (ORs).

Results: A total of 14 studies involving 1312 patients were included. The up-regulated expression level of HULC was associated with poorer overall survival (OS) in patients with digestive system tumors (HR = 1.83, 95% CI: 1.05-3.19, P = 0.033). Subgroup analysis showed that cancer type (pancreatic cancer or gastric cancer), residence region (China, Japan or Korea), and specimen (serum) significantly associated between HULC and OS. In addition, high HULC expression significantly increased the risk of high TNM stage (OR = 2.51, 95%CI: 1.36-4.62, P < 0.05), poor differentiation (OR = 1.38, 95%CI: 1.02-1.87, P < 0.05) and lymphatic node metastasis (LNM, OR = 4.93, 95% CI: 3.47-6.99, P < 0.05).

Conclusions: High expression level of HULC is related to OS, TNM stage, differentiation and LNM. Therefore, HULC can be used as a new potential predictor for prognosis and clinicopathological features of patients with digestive system tumors.

Whole-genome-scale identification of novel non-protein-coding RNAs controlling cell proliferation and survival through a functional forward genetics strategy

Identification of cell fate-controlling lncRNAs is essential to our understanding of molecular cell biology. Here we present a human genome-scale forward-genetics approach for the identification of lncRNAs based on gene function. This approach can identify genes that play a causal role, and immediately distinguish them from those that are differentially expressed but do not affect cell function. Our genome-scale library plus next-generation-sequencing and bioinformatic approach, radically upscales the breadth and rate of functional ncRNA discovery. Human gDNA was digested to produce a lentiviral expression library containing inserts in both sense and anti-sense orientation. The library was used to transduce human Jurkat T-leukaemic cells. Cell populations were selected using continuous culture ± anti-FAS IgM, and sequencing used to identify sequences controlling cell proliferation. This strategy resulted in the identification of thousands of new sequences based solely on their function including many ncRNAs previously identified as being able to modulate cell survival or to act as key cancer regulators such as AC084816.1*, AC097103.2, AC087473.1, CASC15*, DLEU1*, ENTPD1-AS1*, HULC*, MIRLET7BHG*, PCAT-1, SChLAP1, and TP53TG1. Independent validation confirmed 4 out of 5 sequences that were identified by this strategy, conferred a striking resistance to anti-FAS IgM-induced apoptosis.

The Nucleus/Mitochondria-Shuttling LncRNAs Function as New Epigenetic Regulators of Mitophagy in Cancer

Mitophagy is a specialized autophagic pathway responsible for the selective removal of damaged or dysfunctional mitochondria by targeting them to the autophagosome in order to maintain mitochondria quality. The role of mitophagy in tumorigenesis has been conflicting, with the process both supporting tumor cell survival and promoting cell death. Cancer cells may utilize the mitophagy pathway to augment their metabolic requirements and resistance to cell death, thereby leading to increased cell proliferation and invasiveness. This review highlights major regulatory pathways of mitophagy involved in cancer. In particular, we summarize recent progress regarding how nuclear-encoded long non-coding RNAs (lncRNAs) function as novel epigenetic players in the mitochondria of cancer cells, affecting the malignant behavior of tumors by regulating mitophagy. Finally, we discuss the potential application of regulating mitophagy as a new target for cancer therapy.

Circulating Long and Circular Noncoding RNA as Non-Invasive Diagnostic Tools of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide, partially due to late diagnosis of the disease. Growing evidence in the field of biomarker discovery has shown the promising use of nucleic acid in the early detection of many cancers, including HCC. Here, we review data on how various long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) could be used as a diagnostic tool for HCC being differentially expressed in HCC compared to non-HCC patients. These non-coding RNAs (ncRNAs) showed high stability in the blood being present as free-circulating molecules or encapsulated into exosomes. This review reports some recent evidence on the use of lncRNAs and circRNAs as possible diagnostic biomarkers for HCC. Further, their pathophysiological mechanism in liver carcinogenesis was also described, elucidating the complex regulatory networks making these ncRNAs of particular relevance for the study of liver malignancy cancer.

MiRNA and LncRNA as Potential Biomarkers in Triple-Negative Breast Cancer: A Review

Noncoding RNAs (ncRNAs) include a diverse range of RNA species, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). MiRNAs, ncRNAs of approximately 19-25 nucleotides in length, are involved in gene expression regulation either via degradation or silencing of the messenger RNAs (mRNAs) and have roles in multiple biological processes, including cell proliferation, differentiation, migration, angiogenesis, and apoptosis. LncRNAs, which are longer than 200 nucleotides, comprise one of the largest and most heterogeneous RNA families. LncRNAs can activate or repress gene expression through various mechanisms, acting alone or in combination with miRNAs and other molecules as part of various pathways. Until recently, most research has focused on individual lncRNA and miRNA functions as regulators, and there is limited available data on ncRNA interactions relating to the tumor growth, metastasis, and therapy of cancer, acting either on mRNA alone or as competing endogenous RNA (ceRNA) networks. Triple-negative breast cancer (TNBC) represents approximately 10%-20% of all breast cancers (BCs) and is highly heterogenous and more aggressive than other types of BC, for which current targeted treatment options include hormonotherapy, PARP inhibitors, and immunotherapy; however, no targeted therapies for TNBC are available, partly because of a lack of predictive biomarkers. With advances in proteomics, new evidence has emerged demonstrating the implications of dysregulation of ncRNAs in TNBC etiology. Here, we review the roles of lncRNAs and miRNAs implicated in TNBC, including their interactions and regulatory networks. Our synthesis provides insight into the mechanisms involved in TNBC progression and has potential to aid the discovery of new diagnostic and therapeutic strategies.

Identification of Potential Prognostic Long Non-Coding RNA Biomarkers for Predicting Recurrence in Patients with Cervical Cancer

Background

Cervical cancer (CC) is one of the most common malignant tumors in women, and its treatment is often accompanied by high recurrence. We aimed to identify the long non-coding RNAs (lncRNAs) associated with CC recurrence.

Methods

We downloaded lncRNAs expression data of CC patients from The Cancer Genome Atlas (TCGA) dataset and used Cox regression models to analyze the lncRNAs relationship with CC recurrence. The significantly associated lncRNAs were utilized to construct a recurrence risk score (RRS) model. Bioinformatics analyses were used to assess the potential role of the critical lncRNAs in CC recurrence. The effect of critical lncRNAs on CC phenotype was determined by in vitro experiments.

Results

Using Cox regression analysis, four lncRNAs, ie, HCG11, CASC15, LINC00189, and LINC00905, were markedly associated with worse recurrence-free survival (RFS) of CC, whereas three lncRNAs, including HULC, LINC00173, and MIR22HG, were the opposite. After constructing the RRS model, Kaplan-Meier analysis revealed that patients with high RRS had significantly increased risk of recurrence. Among the 20 types of tumors in the TCGA database which all had adjacent normal tissues, MIR22HG and HCG11were significantly downregulated in 18 and 10 types of tumors including CC, respectively. Increased MIR22HG was significantly relevant to decreased risks of recurrence among the subgroups of age at diagnosis < 45 (Hazard Ratio (HR) = 0.26), stage I/II (HR = 0.33), T stage I/II (HR = 0.30), chemotherapy (HR = 0.18), and molecular therapy (HR = 0.16). Functionally, elevated MIR22HG expression could suppress CC cell proliferation, migration and invasion.

Conclusion

MIR22HG has a fundamental role in CC recurrence and could be served as a potential prognostic biomarker.