LncRNA PTPRG-AS1 Promotes the Metastasis of Hepatocellular Carcinoma by Enhancing YWHAG

Mechanism of HOXA10 in nasopharyngeal carcinoma cell proliferation through the PTPRG-AS1/USP1 axis

Nasopharyngeal carcinoma (NPC) is an epithelial carcinoma arising from the nasopharyngeal mucosal lining. The present study sought to analyze the mechanism by which homeobox A10 (HOXA10) affects NPC cell proliferation. The expression levels of HOXA10/long noncoding RNA (lncRNA) PTPRG antisense RNA 1 (PTPRG-AS1)/ubiquitin-specific peptidase 1 (USP1) in NPC tissues and cells were determined. Cell proliferation was evaluated. The enrichment of HOXA10 on the PTPRG-AS1 promoter was determined. The binding of PTPRG-AS1, HuR, and USP1 to each other was analyzed via RNA immunoprecipitation. USP1 mRNA stability was determined after actinomycin D treatment. The role of the PTPRG-AS1/USP1 axis in NPC cell proliferation was analyzed in combined experiments. The role of HOXA10 in vivo was confirmed in xenograft tumor models. The results revealed that HOXA10 was overexpressed in NPC. HOXA10 downregulation reduced NPC cell proliferation. PTPRG-AS1 and USP1 were upregulated in NPC. HOXA10 bound to the PTPRG-AS1 promoter to increase PTPRG-AS1 expression, and the binding of PTPRG-AS1 to HuR increased USP1 expression. PTPRG-AS1 or USP1 overexpression attenuated the inhibitory effects of HOXA10 downregulation on NPC cell proliferation. HOXA10 downregulation inhibited in vivo NPC proliferation through the PTPRG-AS1/USP1 axis. In conclusion, HOXA10 facilitates NPC cell proliferation in vitro and in vivo through the PTPRG-AS1/USP1 axis.

POU2F2-mediated upregulation of lncRNA PTPRG-AS1 inhibits ferroptosis in breast cancer via miR-376c-3p/SLC7A11 axis

Background: Triple-negative breast cancer (TNBC) is a subtype of BC with high rates of mortality. The mechanism of PTPRG-AS1 in ferroptosis of TNBC was investigated. Methods: Chromatin immunoprecipitation and dual-luciferase reporter assays were used to measure intermolecular relationships. MTT and colony formation assays detected cell viability and proliferation. Kits detected Fe2+ and reactive oxygen species levels. The role of PTPRG-AS1 in tumor growth was analyzed in vivo. Results: PTPRG-AS1 was increased in TNBC tissues and cells. PTPRG-AS1 silencing increased the reduction of glutathione and GPX4, increased Fe2+ and reactive oxygen species in erastin-treated cells and inhibited proliferation. POU2F2 transcriptionally upregulated PTPRG-AS1. PTPRG-AS1 targeted miR-376c-3p to upregulate SLC7A11. PTPRG-AS1 knockdown suppressed tumor growth in vivo. Conclusion: POU2F2 transcriptionally activates PTPRG-AS1 to modulate ferroptosis and proliferation by miR-376c-3p/SLC7A11, promoting TNBC.

YWHAG Deficiency Disrupts the EMT-Associated Network to Induce Oxidative Cell Death and Prevent Metastasis

Metastasis involves epithelial-to-mesenchymal transition (EMT), a process that is regulated by complex gene networks, where their deliberate disruption may yield a promising outcome. However, little is known about mechanisms that coordinate these metastasis-associated networks. To address this gap, hub genes with broad engagement across various human cancers by analyzing the transcriptomes of different cancer cell types undergoing EMT are identified. The oncogenic signaling adaptor protein tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) is ranked top for its clinical relevance and impact. The cellular kinome and transcriptome data are surveyed to construct the regulome of YWHAG, revealing stress responses and metabolic processes during cancer EMT. It is demonstrated that a YWHAG-dependent cytoprotective mechanism in the regulome is embedded in EMT-associated networks to protect cancer cells from oxidative catastrophe through enhanced autophagy during EMT. YWHAG deficiency results in a rapid accumulation of reactive oxygen species (ROS), delayed EMT, and cell death. Tumor allografts show that metastasis potential and overall survival time are correlated with the YWHAG expression level of cancer cell lines. Metastasized tumors have higher expression of YWHAG and autophagy-related genes than primary tumors. Silencing YWHAG diminishes primary tumor volumes, prevents metastasis, and prolongs the median survival period of the mice.

Long non-coding RNAs (lncRNAs) in hepatocellular carcinoma progression: Biological functions and new therapeutic targets

Liver is an important organ in body that performs vital functions such as detoxification. Liver is susceptible to development of cancers, and hepatocellular carcinoma (HCC) is among them. 75-85% of liver cancer cases are related to HCC. Therefore, much attention has been directed towards understanding factors mediating HCC progression. LncRNAs are epigenetic factors with more than 200 nucleotides in length located in both nucleus and cytoplasm and they are promising candidates in cancer therapy. Directing studies towards understanding function of lncRNAs in HCC is of importance. LncRNAs regulate cell cycle progression and growth of HCC cells, and they can also induce/inhibit apoptosis in tumor cells. LncRNAs affect invasion and metastasis in HCC mainly by epithelial-mesenchymal transition (EMT) mechanism. Revealing the association between lncRNAs and downstream signaling pathways in HCC is discussed in the current manuscript. Infectious diseases can affect lncRNA expression in mediating HCC development and then, altered expression level of lncRNA is associated with drug resistance and radio-resistance. Biomarker application of lncRNAs and their role in prognosis and diagnosis of HCC are also discussed to pave the way for treatment of HCC patients.

Interactions between 14-3-3 Proteins and Actin Cytoskeleton and Its Regulation by microRNAs and Long Non-Coding RNAs in Cancer

14-3-3s are a family of structurally similar proteins that bind to phosphoserine or phosphothreonine residues, forming the central signaling hub that coordinates or integrates various cellular functions, thereby controlling many pathways important in cancer, cell motility, cell death, cytoskeletal remodeling, neuro-degenerative disorders and many more. Their targets are present in all cellular compartments, and when they bind to proteins they alter their subcellular localization, stability, and molecular interactions with other proteins. Changes in environmental conditions that result in altered homeostasis trigger the interaction between 14-3-3 and other proteins to retrieve or rescue homeostasis. In circumstances where these regulatory proteins are dysregulated, it leads to pathological conditions. Therefore, deeper understanding is needed on how 14-3-3 proteins bind, and how these proteins are regulated or modified. This will help to detect disease in early stages or design inhibitors to block certain pathways. Recently, more research has been devoted to identifying the role of MicroRNAs, and long non-coding RNAs, which play an important role in regulating gene expression. Although there are many reviews on the role of 14-3-3 proteins in cancer, they do not provide a holistic view of the changes in the cell, which is the focus of this review. The unique feature of the review is that it not only focuses on how the 14-3-3 subunits associate and dissociate with their binding and regulatory proteins, but also includes the role of micro-RNAs and long non-coding RNAs and how they regulate 14-3-3 isoforms. The highlight of the review is that it focuses on the role of 14-3-3, actin, actin binding proteins and Rho GTPases in cancer, and how this complex is important for cell migration and invasion. Finally, the reader is provided with super-resolution high-clarity images of each subunit of the 14-3-3 protein family, further depicting their distribution in HeLa cells to illustrate their interactions in a cancer cell.