Steroid receptor coactivator-1 enhances the stemness of glioblastoma by activating long noncoding RNA XIST/miR-152/KLF4 pathway

Oncogenic roles of long non-coding RNAs in essential glioblastoma signaling pathways

Glioblastoma multiforme (GBM) is an aggressive and diffuse type of glioma with the lowest survival rate in patients. The recent failure of multiple treatments suggests that targeting several targets at once may be a different strategy to overcome GBM carcinogenesis. Normal function of oncogenes and tumor suppressor genes need for the preservation of regular cellular processes, so any defects in these genes' activity, operate the corresponding signaling pathways, which initiate carcinogenic processes. Long non-coding RNAs (lncRNAs) that can be found in the cytoplasm or nucleus of the cells, control the transcription and translation of genes. LncRNAs perform a variety of functions, including epigenetic alteration, protein modification and stability, transcriptional regulation, and competition for miRNA that regulate mRNA translation through sponging miRNAs. Identification of various oncogenic lncRNAs and their multiple roles in brain cancers making them potential candidates for use as glioma diagnostic, prognostic, and therapeutic targets in the future. This study highlighted multiple oncogenic lncRNAs and classified them into different signaling pathways based on the regulated target genes in glioblastoma.

Glioblastoma stem cell long non-coding RNAs: therapeutic perspectives and opportunities

Glioblastoma poses a formidable challenge among primary brain tumors: its tumorigenic stem cells, capable of self-renewal, proliferation, and differentiation, contribute substantially to tumor initiation and therapy resistance. These glioblastoma stem cells (GSCs), resembling conventional stem and progenitor cells, adopt pathways critical for tissue development and repair, promoting uninterrupted tumor expansion. Long non-coding RNAs (lncRNAs), a substantial component of the human transcriptome, have garnered considerable interest for their pivotal roles in normal physiological processes and cancer pathogenesis. They display cell- or tissue-specific expression patterns, and extensive investigations have highlighted their impact on regulating GSC properties and cellular differentiation, thus offering promising avenues for therapeutic interventions. Consequently, lncRNAs, with their ability to exert regulatory control over tumor initiation and progression, have emerged as promising targets for innovative glioblastoma therapies. This review explores notable examples of GSC-associated lncRNAs and elucidates their functional roles in driving glioblastoma progression. Additionally, we delved deeper into utilizing a 3D in vitro model for investigating GSC biology and elucidated four primary methodologies for targeting lncRNAs as potential therapeutics in managing glioblastoma.

Exosomal lncRNA XIST promotes perineural invasion of pancreatic cancer cells via miR-211-5p/GDNF

Perineural invasion (PNI) is an essential form of tumor metastasis in multiple malignant cancers, such as pancreatic cancer, prostate cancer, and head and neck cancer. Growing evidence has revealed that pancreatic cancer recurrence and neuropathic pain positively correlate with PNI. Therefore, targeting PNI is a proper strategy for pancreatic cancer treatment. Exosomal lncRNA derived from pancreatic cancer cells is an essential component of the tumor microenvironment. However, whether exosomal lncXIST derived from pancreatic cancer cells can promote PNI and its exact mechanism remains to be elucidated. We show that lncXIST mediates nerve-tumor crosstalk via exosomal delivery. Our data reveal that exosomal lncXIST derived from pancreatic cancer cells is delivered to neural cells and promotes their release of glial-cell-line-derived neurotrophic factor (GDNF), essential in facilitating the PNI of pancreatic cancer. Mechanistically, microRNA-211-5p negatively regulates GDNF, and lncXIST serves as a miR-211-5p sponge. The function of exosomes in the dynamic interplay between nerves and cancer is confirmed in both in vivo and in vitro PNI models. Therefore, targeting pancreatic cancer cell-derived exosomal lncXIST may provide clues for a promising approach for developing a new strategy to combat PNI of pancreatic cancer.

The multifaceted therapeutic value of targeting steroid receptor coactivator-1 in tumorigenesis

Steroid receptor coactivator-1 (SRC-1, also known as NCOA1) frequently functions as a transcriptional coactivator by directly binding to transcription factors and recruiting to the target gene promoters to promote gene transcription by increasing chromatin accessibility and promoting the formation of transcriptional complexes. In recent decades, various biological and pathological functions of SRC-1 have been reported, especially in the context of tumorigenesis. SRC-1 is a facilitator of the progression of multiple cancers, including breast cancer, prostate cancer, gastrointestinal cancer, neurological cancer, and female genital system cancer. The emerging multiorgan oncogenic role of SRC-1 is still being studied and may not be limited to only steroid hormone-producing tissues. Growing evidence suggests that SRC-1 promotes target gene expression by directly binding to transcription factors, which may constitute a novel coactivation pattern independent of AR or ER. In addition, the antitumour effect of pharmacological inhibition of SRC-1 with agents including various small molecules or naturally active compounds has been reported, but their practical application in clinical cancer therapy is very limited. For this review, we gathered typical evidence on the oncogenic role of SRC-1, highlighted its major collaborators and regulatory genes, and mapped the potential mechanisms by which SRC-1 promotes primary tumour progression.

Dysregulated lipid metabolism in TMZ-resistant glioblastoma: pathways, proteins, metabolites and therapeutic opportunities

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor with limited treatment options, such as the chemotherapeutic agent, temozolomide (TMZ). However, many GBM tumors develop resistance to TMZ, which is a major obstacle to effective therapy. Recently, dysregulated lipid metabolism has emerged as an important factor contributing to TMZ resistance in GBM. The dysregulation of lipid metabolism is a hallmark of cancer and alterations in lipid metabolism have been linked to multiple aspects of tumor biology, including proliferation, migration, and resistance to therapy. In this review, we aimed to summarize current knowledge on lipid metabolism in TMZ-resistant GBM, including key metabolites and proteins involved in lipid synthesis, uptake, and utilization, and recent advances in the application of metabolomics to study lipid metabolism in GBM. We also discussed the potential of lipid metabolism as a target for novel therapeutic interventions. Finally, we highlighted the challenges and opportunities associated with developing these interventions for clinical use, and the need for further research to fully understand the role of lipid metabolism in TMZ resistance in GBM. Our review suggests that targeting dysregulated lipid metabolism may be a promising approach to overcome TMZ resistance and improve outcomes in patients with GBM.

Natural flavonoids alleviate glioblastoma multiforme by regulating long non-coding RNA

Glioblastoma multiforme (GBM) is one of the most common primary malignant brain tumors in adults. Due to the poor prognosis of patients, the median survival time of GBM is often less than 1 year. Therefore, it is very necessary to find novel treatment options with a good prognosis for the treatment or prevention of GBM. In recent years, flavonoids are frequently used to treat cancer. It is a new attractive molecule that may achieve this promising treatment option. Flavonoids have been proved to have many biological functions, such as antioxidation, prevention of angiogenesis, anti-inflammation, inhibition of cancer cell proliferation, and protection of nerve cells. It has also shown the ability to regulate long non-coding RNA (LncRNA). Studies have confirmed that flavonoids can regulate epigenetic modification, transcription, and change microRNA (miRNA) expression of GBM through lncRNA at the gene level. It also found that flavonoids can induce apoptosis and autophagy of GBM cells by regulating lncRNA. Moreover, it can improve the metabolic abnormalities of GBM, interfere with the tumor microenvironment and related signaling pathways, and inhibit the angiogenesis of GBM cells. Eventually, flavonoids can block the tumor initiation, growth, proliferation, differentiation, invasion, and metastasis. In this review, we highlight the role of lncRNA in GBM cancer progression and the influence of flavonoids on lncRNA regulation. And emphasize their expected role in the prevention and treatment of GBM.

Bufalin-Mediated Regulation of Cell Signaling Pathways in Different Cancers: Spotlight on JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, and Non-Coding RNAs

The renaissance of research into natural products has unequivocally and paradigmatically shifted our knowledge about the significant role of natural products in cancer chemoprevention. Bufalin is a pharmacologically active molecule isolated from the skin of the toad Bufo gargarizans or Bufo melanostictus. Bufalin has characteristically unique properties to regulate multiple molecular targets and can be used to harness multi-targeted therapeutic regimes against different cancers. There is burgeoning evidence related to functional roles of signaling cascades in carcinogenesis and metastasis. Bufalin has been reported to regulate pleiotropically a myriad of signal transduction cascades in various cancers. Importantly, bufalin mechanistically regulated JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, EGFR, and c-MET pathways. Furthermore, bufalin-mediated modulation of non-coding RNAs in different cancers has also started to gain tremendous momentum. Similarly, bufalin-mediated targeting of tumor microenvironments and tumor macrophages is an area of exciting research and we have only started to scratch the surface of the complicated nature of molecular oncology. Cell culture studies and animal models provide proof-of-concept for the impetus role of bufalin in the inhibition of carcinogenesis and metastasis. Bufalin-related clinical studies are insufficient and interdisciplinary researchers require detailed analysis of the existing knowledge gaps.

The pathogenic roles of lncRNA-Taurine upregulated 1 (TUG1) in colorectal cancer

Colorectal cancer (CRC) is a gastrointestinal tumor that develops from the colon, rectum, or appendix. The prognosis of CRC patients especially those with metastatic lesions remains unsatisfactory. Although various conventional methods have been used for the treatment of patients with CRC, the early detection and identification of molecular mechanisms associated with CRC is necessary. The scientific literature reports that altered expression of long non-coding RNAs (lncRNAs) contributed to the pathogenesis of CRC cells. LncRNA TUG1 was reported to target various miRNAs and signaling pathways to mediate CRC cell proliferation, migration, and metastasis. Therefore, TUG1 might be a potent predictive/prognostic biomarker for diagnosis of CRC.

Bufalin for an innovative therapeutic approach against cancer

Bufalin is an endogenous cardiotonic steroid, first discovered in toad venom but also found in the plasma of healthy humans, with anti-tumour activities in different cancer types. The current review is focused on its mechanisms of action and highlights its very large spectrum of effects both in vitro and in vivo. All leads to the conclusion that bufalin mediates its effects by affecting all the hallmarks of cancer and seems restricted to cancer cells avoiding side effects. Bufalin decreases cancer cell proliferation by acting on the cell cycle and inducing different mechanisms of cell death including apoptosis, necroptosis, autophagy and senescence. Bufalin also moderates metastasis formation by blocking migration and invasion as well as angiogenesis and by inducing a phenotype switch towards differentiation and decreasing cancer cell stemness. Regarding its various mechanisms of action in cancer cells, bufalin blocks overactivated signalling pathways and modifies cell metabolism. Moreover, bufalin gained lately a huge interest in the field of drug resistance by both reversing various drug resistance mechanisms and affecting the immune microenvironment. Together, these data support bufalin as a quite promising new anti-cancer drug candidate.

Silencing of lncRNA CHRM3-AS2 Expression Exerts Anti-Tumour Effects Against Glioma via Targeting microRNA-370-5p/KLF4

Objectives

Long non-coding RNAs (lncRNAs) are key regulators involved in the progression of glioma, and many functional lncRNAs are yet to be identified. This study aimed to explore the function of CHRM3-AS2, a rarely reported lncRNA, in glioma, as well as the underlying mechanisms involving miR-370-5p/KLF4.

Methods

Differentially expressed RNAs (DERs) were screened from two gene expression profiles of glioblastoma (GBM). Fluorescence in situ hybridisation was performed to determine the subcellular localisation of CHRM3-AS2. Cell viability, colony formation, apoptosis, migration, and invasion were evaluated using cell counting kit-8, colony counts, flow cytometry, wound healing, and Transwell assays, respectively. mRNA and protein expression of specific genes were measured using quantitative real-time polymerase chain reaction and western blotting, respectively. Dual luciferase reporter gene, RNA immunoprecipitation, and RNA pull-down assays were performed to identify the target relationships. A mouse xenograft model was established for in vivo validation.

Results

CHRM3-AS2 was screened as a prognosis-associated DER in GBM. CHRM3-AS2 expression was up-regulated in glioma cells, and CHRM3-AS2 was localised in the cytoplasm. Silencing of CHRM3-AS2 expression inhibited cell viability, colony formation, migration, and invasion and promoted apoptosis of U251 and SHG-44 cells. In addition, CHRM3-AS2 targeted miR-370-5p/KLF4 in glioma cells. The anti-tumour effect of CHRM3-AS2 silencing was weakened by miR-370-5p silencing or KLF4 overexpression. In vivo, silencing of CHRM3-AS2 expression inhibited tumour growth and Ki67 expression in mice. Overexpression of KLF4 also weakened the anti-tumour effect of CHRM3-AS2 silencing in mice.

Conclusions

Silencing of CHRM3-AS2 expression inhibited the malignant progression of glioma by regulating miR-370-5p/KLF4 expression.

Long non-coding RNA XIST: a novel oncogene in multiple cancers

Long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) is an important lncRNA derived from the XIST gene in mammals. XIST is abnormally expressed in numerous tumors, in most of which XIST functions as an oncogene. XIST is involved in multiple aspects of carcinogenesis, including tumor onset, progression, and prognosis. In our review, we collected and analyzed the recent studies on the impact of XIST in human tumor development. The multilevel molecular functions of XIST in human tumors are comprehensively reviewed to clarify the pathologic mechanisms and to offer a novel direction for further study.

Long Non-Coding RNAs in Diagnosis, Treatment, Prognosis, and Progression of Glioma: A State-of-the-Art Review

Glioma is the most common malignant central nervous system tumor with significant mortality and morbidity. Despite considerable advances, the exact molecular pathways involved in tumor progression are not fully elucidated, and patients commonly face a poor prognosis. Long non-coding RNAs (lncRNAs) have recently drawn extra attention for their potential roles in different types of cancer as well as non-malignant diseases. More than 200 lncRNAs have been reported to be associated with glioma. We aimed to assess the roles of the most investigated lncRNAs in different stages of tumor progression and the mediating molecular pathways in addition to their clinical applications. lncRNAs are involved in different stages of tumor formation, invasion, and progression, including regulating the cell cycle, apoptosis, autophagy, epithelial-to-mesenchymal transition, tumor stemness, angiogenesis, the integrity of the blood-tumor-brain barrier, tumor metabolism, and immunological responses. The well-known oncogenic lncRNAs, which are upregulated in glioma, are H19, HOTAIR, PVT1, UCA1, XIST, CRNDE, FOXD2-AS1, ANRIL, HOXA11-AS, TP73-AS1, and DANCR. On the other hand, MEG3, GAS5, CCASC2, and TUSC7 are tumor suppressor lncRNAs, which are downregulated. While most studies reported oncogenic effects for MALAT1, TUG1, and NEAT1, there are some controversies regarding these lncRNAs. Expression levels of lncRNAs can be associated with tumor grade, survival, treatment response (chemotherapy drugs or radiotherapy), and overall prognosis. Moreover, circulatory levels of lncRNAs, such as MALAT1, H19, HOTAIR, NEAT1, TUG1, GAS5, LINK-A, and TUSC7, can provide non-invasive diagnostic and prognostic tools. Modulation of expression of lncRNAs using antisense oligonucleotides can lead to novel therapeutics. Notably, a profound understanding of the underlying molecular pathways involved in the function of lncRNAs is required to develop novel therapeutic targets. More investigations with large sample sizes and increased focus on in-vivo models are required to expand our understanding of the potential roles and application of lncRNAs in glioma.

X-Inactive-Specific Transcript: Review of Its Functions in the Carcinogenesis

X-inactive-specific transcript (XIST) is one of the firstly discovered long non-coding RNAs with prominent roles in the process of X inactivation. Moreover, this transcript contributes in the carcinogenic process in different tissues. In addition to interacting with chromatin modifying molecules, XIST can be served as a molecular sponge for miRNAs to modulate expression of miRNA targets. Most of the studies have indicated an oncogenic role for XIST. However, in prostate cancer, a single study has indicated a tumor suppressor role for this lncRNA. Similar result has been reported for XIST in oral squamous cell carcinoma. In hepatocellular carcinoma, breast cancer, ovarian cancer, osteosarcoma, and renal cell carcinoma, different studies have reported inconsistent results. In the present manuscript, we review function of XIST in the carcinogenesis.

Current research advances in microRNA-mediated regulation of Krüppel-like factor 4 in cancer: a narrative review

Objective

The purpose of this study was to investigate the miRNAs and related mechanisms that regulates KLF4 in different cancers. Furthermore, we summarized the potential targets of miRNAs regulating the KLF4 pathway in cancer research.

Background

MiRNAs are single-stranded, endogenous non-coding small RNAs, some of which are related to human cancers. miRNAs carry out post-transcriptional gene regulation through translation inhibition and degradation of target messenger RNAs (mRNAs) via complementarily pairing with their 3' untranslated regions. KLF4 is an important transcription factor with complex involvement in cancer. Increasing evidence shows that miRNAs are dysregulated in cancer and can regulate cancer-related signaling pathways, thereby affecting tumor progression.

Methods

Systematic scientific literature searches were undertaken on PubMed using the following terms: "miRNAs and KLF4", "KLF4 and cancer", "miRNAs and cancer", and "miRNAs, KLF4 and cancer". Relevant papers were retrieved and further results were found by reviewing related papers and the references of the retrieved papers. We then conducted a narrative overview of the literature to summarize the results of the papers.

Conclusions

The role of KLF4 in cancer varies in a context-dependent manner. KLF4-regulating miRNAs in different tumors include miR-124, miR-9-5p, miR-10b, miR-18a, miR-25-3p, miR-10b, miR-92a, miR-103, miR-155, miR-135b-5p, miR-32-5p, miR-148-3p, miR-152-3p, miR-10b, miR-25, miR-3120-5p, miR-7, miR-1233-3p, miR-10b, miR-145, miR-139-5p, miR-16, miR-152, miR-375, and miR-145.

Role of long noncoding RNA taurine-upregulated gene 1 in cancers

Long non-coding RNAs (lncRNAs) are a group of non-protein coding RNAs with a length of more than 200 bp. The lncRNA taurine up-regulated gene 1 (TUG1) is abnormally expressed in many human malignant cancers, where it acts as a competitive endogenous RNA (ceRNA), regulating gene expression by specifically sponging its corresponding microRNAs. In the present review, we summarised the current understanding of the role of lncRNA TUG1 in cancer cell proliferation, metastasis, angiogenesis, chemotherapeutic drug resistance, radiosensitivity, cell regulation, and cell glycolysis, as well as highlighting its potential application as a clinical biomarker or therapeutic target for malignant cancer. This review provides the basis for new research directions for lncRNA TUG1 in cancer prevention, diagnosis, and treatment.

Cancer stem cells and macrophages: molecular connections and future perspectives against cancer

Cancer stem cells (CSCs) have been considered the key drivers of cancer initiation and progression due to their unlimited self-renewal capacity and their ability to induce tumor formation. Macrophages, particularly tumor-associated macrophages (TAMs), establish a tumor microenvironment to protect and induce CSCs development and dissemination. Many studies in the past decade have been performed to understand the molecular mediators of CSCs and TAMs, and several studies have elucidated the complex crosstalk that occurs between these two cell types. The aim of this review is to define the complex crosstalk between these two cell types and to highlight potential future anti-cancer strategies.

Steroid receptor coactivator-1 enhances the stemness of glioblastoma by activating long noncoding RNA XIST/miR-152/KLF4 pathway

Glioblastoma (GBM) recurrence is attributed to the presence of therapy-resistant glioblastoma stem cells. Steroid receptor coactivator-1 (SRC-1) acts as an oncogenic regulator in many human tumors. The relationship between SRC-1 and GBM has not yet been studied. Herein, we investigate the role of SRC-1 in GBM. In this study, we found that SRC-1 expression is positively correlated with grades of glioma and inversely correlated with glioma patient's prognosis. Steroid receptor coactivator-1 promotes the proliferation, migration, and tumor growth of GBM cells. Notably, SRC-1 knockdown suppresses the stemness of GBM cells. Mechanistically, long noncoding RNA X-inactive specific transcript (XIST) is regulated by SRC-1 at the posttranscriptional level and mediates the function of SRC-1 in promoting stemness-like properties of GBM. Steroid receptor coactivator-1 can promote the expression of Kruppel-like factor 4 (KLF4) through the XIST/microRNA (miR)-152 axis. Additionally, arenobufagin and bufalin, SRC small molecule inhibitors, can reduce the proliferation and stemness of GBM cells. This study reveals SRC-1 promotes the stemness of GBM by activating the long noncoding RNA XIST/miR-152/KLF4 pathway and provides novel markers for diagnosis and therapy of GBM.