SIAH1 reverses chemoresistance in epithelial ovarian cancer via ubiquitination of YBX-1

Y-box binding protein 1: A critical target for understanding and treating cardiovascular disease

Cardiovascular diseases (CVDs) remain a significant public health burden, characterized by escalating morbidity and mortality rates and demanding novel therapeutic approaches. Cold shock protein Y-box binding protein 1 (YB-1), a highly conserved RNA/DNA-binding protein, has emerged as a pivotal regulator in various pathophysiological processes, including CVDs. YB-1 exerts pleiotropic functions by modulating gene transcription, pre-mRNA splicing, mRNA translation, and stability. The expression and function of YB-1 are intricately regulated by its subcellular localization, post-translational modifications, upstream regulatory signals. YB-1 plays a multifaceted role in CVDs, influencing inflammation, oxidative stress, cell proliferation, apoptosis, phenotypic switching of smooth muscle cells, and mitochondrial dysfunction. However, the regulation of YB-1 expression and function in CVDs is complex and context-dependent, exhibiting divergent effects even in the same disease across different cell types or at disease stages. This review comprehensively explores the structure, regulation, and functional significance of YB-1 in CVDs. We delve into the transcriptional and translational control mechanisms of YB-1, as well as its post-translational modifications. Furthermore, we elucidate the upstream signaling pathways that influence YB-1 expression, with a particular emphasis on non-coding RNAs and specific upstream molecules. Finally, we systematically examine the role of YB-1 in CVDs, summarizing its expression patterns, regulatory mechanisms, and therapeutic potential as a promising target for novel therapeutic interventions. By providing a comprehensive overview of YB-1's involvement in CVDs, this review aims to stimulate further research and facilitate the development of targeted therapies to improve cardiovascular health.

RNA epigenetic modifications as dynamic biomarkers in cancer: from mechanisms to clinical translation

RNA modifications are crucial for post-transcriptional gene regulation. Research on RNA modifications has become a novel frontier of epitranscriptomics. Up to now, over 170 kinds of modifications have been identified on mRNA and diverse non-coding RNA. Three classes of proteins (writers, erasers, and readers) regulate the addition, removal, and identification of epigenetic marks, thus affecting RNA biological functions. Increasing evidence identifies the dysregulation of RNA modifications in different cancer types and the therapeutic potential of targeting RNA-modifying enzymes. The ability of RNA modifications to improve mRNA stability and translation efficacy and decrease immunogenicity has been exploited for the clinical use of mRNA cancer vaccines. This review aims to shed light on several vital cap, tail, and internal modifications of RNA with a focus on the connection between RNA epigenetic pathways and cancer pathogenesis. We further explore the clinical potential of RNA modifications as dynamic biomarkers for cancer diagnosis, prognosis, and therapeutic response prediction, addressing both technological challenges and translational opportunities. Finally, we analyze the limitations of current studies and discuss the research focus in the future.

5-Methylcytosine RNA modification and its roles in cancer and cancer chemotherapy resistance

Recent advancements in cancer therapies have improved clinical outcomes, yet therapeutic resistance remains a significant challenge because of its complex mechanisms. Among epigenetic factors, m5C RNA modification is emerging as a key player in cancer drug resistance, similar to the well-known m6A modification. m5C affects RNA metabolism processes, including splicing, export, translation, and stability, thereby influencing drug efficacy. This review highlights the critical roles of m5C in modulating resistance to chemotherapy, targeted therapy, radiotherapy, and immunotherapy. This review also discusses the functions of key regulators, including methyltransferases, demethylases, and m5C-binding proteins, as essential modulators of the m5C epigenetic landscape that contribute to its dynamic and complex regulatory network. Targeting these regulatory components offers a promising strategy to overcome resistance. We highlight the need for further research to elucidate the specific mechanisms by which m5C contributes to resistance and to develop precise m5C-targeted therapies, presenting m5C-focused strategies as potential novel anticancer treatments.

Significant roles of RNA 5-methylcytosine methylation in cancer

Cancer stands as a leading cause of mortality and poses an escalating threat to global health. Epigenetic dysregulation is pivotal in the onset and advancement of cancer. Recent research on RNA 5-methylcytosine (m5C) methylation has underscored its significant role in cancer. RNA m5C methylation is a key component in gene expression regulation and is intricately linked to cancer development, offering valuable insights for cancer diagnosis, treatment, and prognosis. This review provides an in-depth examination of the three types of regulators associated with RNA m5C methylation and their biological functions. It further investigates the expression and impact of RNA m5C methylation and its regulators in cancer, focusing on their mechanisms in cancer progression and clinical relevance. The current research on inhibitors targeting RNA m5C methylation-related regulators remains underdeveloped, necessitating further exploration and discovery.

YBX1: A Multifunctional Protein in Senescence and Immune Regulation

The Y-box binding protein 1 (YBX1) is a multifunctional protein with a wide range of roles in cell biology. It plays a crucial role in immune modulation, senescence, and disease progression. This review presents a comprehensive analysis of the specific functions and mechanisms of YBX1 in these areas. Initially, YBX1 is shown to be closely associated with cellular senescence and impacts significant biological processes, including cell proliferation, damage repair, and metabolism. This suggests potential applications in the prevention and treatment of senescence-related diseases. Additionally, YBX1 regulates the immune response by controlling the function of immune cells and the expression of immune molecules. It is essential in maintaining immune system homeostasis and impacts the pathological process of various diseases, including tumors. Lastly, the diverse functions of the YBX1 protein make it a promising candidate for the development of innovative therapeutic strategies for diseases. Comprehensive research on its mechanisms could provide novel insights and approaches for the prevention, diagnosis, and treatment of related diseases.

Integrative Investigation of Flavonoids Targeting YBX1 Protein-Protein Interaction Network in Breast Cancer: From Computational Analysis to Experimental Validation

Y-box-binding protein 1 (YBX1) is a multifunctional oncoprotein with its nuclear localization contributing to chemo-resistance in breast cancer. Through its interactions with various proteins and lncRNAs, YBX1 promotes cancer cell migration, invasion, and metastasis. Despite its significant role in cancer progression, studies on YBX1's protein-protein interactions (PPIs) remain limited. Flavonoids are natural compounds with anticancer properties that inhibit metastasis, modulate immunity, and induce apoptosis, with minimal systemic toxicity, making them strong candidates for cancer therapy. Targeting PPIs offers a promising approach for cancer therapy and flavonoids, with their anticancer properties, may modulate these interactions. Our study focused on the YBX1 PPI network, specifically targeting HSPA1A, IGF2BP1, MECP2, G3BP1, EWSR1, PURA, and SYNCRIP. We selected four flavonoids Quercetin, Fisetin, Rutin, and Myricitrin based on literature and conducted 26 docking sessions. Further ADMET analysis indicated Quercetin and Fisetin as more favorable for drug-likeness parameters than Rutin and Myricitrin, which was underscored by MD simulation data. In vitro studies showed that Quercetin and Fisetin downregulated YBX1 expression in a dose-dependent manner (50 μM to 150 μM) in MCF-7 cells. Our study provides a preliminary understanding of YBX1 PPI and the potential of flavonoids to disrupt these interactions. This study investigates the potential of flavonoids to target YBX1 PPIs, providing insights into novel therapeutic strategies for YBX1-driven cancers.

Decoding the epitranscriptome: a new frontier for cancer therapy and drug resistance

As the role of RNA modification in gene expression regulation and human diseases, the "epitranscriptome" has been shown to be an important player in regulating many physiological and pathological processes. Meanwhile, the phenomenon of cancer drug resistance is becoming more and more frequent, especially in the case of cancer chemotherapy resistance. In recent years, research on relationship between post-transcriptional modification and cancer including drug resistance has become a hot topic, especially the methylation of the sixth nitrogen site of RNA adenosine-m6A (N6-methyladenosine). m6A modification is the most common post-transcriptional modification of eukaryotic mRNA, accounting for 80% of RNA methylation modifications. At the same time, several other modifications of RNA, such as N1-methyladenosine (m1A), 5-methylcytosine (m5C), 3-methylcytosine (m3C), pseudouridine (Ψ) and N7-methylguanosine (m7G) have also been demonstrated to be involved in cancer and drug resistance. This review mainly discusses the research progress of RNA modifications in the field of cancer and drug resistance and targeting of m6A regulators by small molecule modulators, providing reference for future study and development of combination therapy to reverse cancer drug resistance.

YB1 and its role in osteosarcoma: a review

YB1 (Y box binding protein 1), a multifunctional protein capable of binding to DNA/RNA, is present in most cells and acts as a splicing factor. It is involved in numerous cellular processes such as transcription, translation, and DNA repair, significantly affecting cell proliferation, differentiation, and apoptosis. Abnormal expression of this protein is closely linked to the formation of various malignancies (osteosarcoma, nasopharyngeal carcinoma, breast cancer, etc.). This review examines the multifaceted functions of YB1 and its critical role in osteosarcoma progression, providing new perspectives for potential therapeutic strategies.

The role of m5C RNA modification in cancer development and therapy

RNA modifications have been demonstrated to affect the function, stability, processing, and interactions of RNA, including pseudouridylation, acetylation and methylation. RNA methylation products, such as N6-methyladenosine (m6A), 5-methylcytidine (m5C), N7-methylguanosine (m7G), 2'-O-dimethyladenosine (m6Am), and N1-methyladenosine (m1A), have been reported to participate in tumorigenesis and tumor progression. The role of m6A in carcinogenesis has been well studied and summarized. In this review, we described the biological functions of m5C RNA modifications in tumorigenesis and tumor progression. Moreover, we highlighted the molecular mechanisms of m5C RNA modification in oncogenesis. Furthermore, we discussed whether targeting m5C regulator-associated genes could be a novel strategy for improving therapeutic outcomes in patients with cancer.

Dynamic RNA methylation modifications and their regulatory role in mammalian development and diseases

Among over 170 different types of chemical modifications on RNA nucleobases identified so far, RNA methylation is the major type of epitranscriptomic modifications existing on almost all types of RNAs, and has been demonstrated to participate in the entire process of RNA metabolism, including transcription, pre-mRNA alternative splicing and maturation, mRNA nucleus export, mRNA degradation and stabilization, mRNA translation. Attributing to the development of high-throughput detection technologies and the identification of both dynamic regulators and recognition proteins, mechanisms of RNA methylation modification in regulating the normal development of the organism as well as various disease occurrence and developmental abnormalities upon RNA methylation dysregulation have become increasingly clear. Here, we particularly focus on three types of RNA methylations: N6-methylcytosine (m6A), 5-methylcytosine (m5C), and N7-methyladenosine (m7G). We summarize the elements related to their dynamic installment and removal, specific binding proteins, and the development of high-throughput detection technologies. Then, for a comprehensive understanding of their biological significance, we also overview the latest knowledge on the underlying mechanisms and key roles of these three mRNA methylation modifications in gametogenesis, embryonic development, immune system development, as well as disease and tumor progression.

Comprehensive analysis of RNA-5-methylcytosine modification in breast cancer brain metastasis

Aim: To delineate the RNA-5-methylcytosine (m5C) modification of breast cancer brain metastasis (BCBM).Methods: Methylated RNA immunoprecipitation next-generation sequencing (MeRIP-seq) was performed to obtain RNA-m5C patterns of BCBM.Results: 1048 hypermethylation and 1866 hypomethylation m5C peaks were identified in BCBM compared with those in breast cancer. The most significant m5C hypermethylated genes included ENG, SHANK1, IGFN1, EVL and MMP9, whereas the most significant m5C hypomethylated genes included AREG, SAA2, TP53I11, KRT7 and LCN2. MeRIP-qPCR data were concordant with the corresponding MeRIP-seq results in terms of the observed m5C levels. Conjoint analysis identified 190 hyper-up genes characterized by concurrent m5C hypermethylation and up-regulation, alongside 284 hypo-down genes exhibiting both m5C hypomethylation and down-regulation.Conclusion: This study presents the first comprehensive analysis of RNA-m5C modification in BCBM.

Regulations of m6A and other RNA modifications and their roles in cancer

RNA modification is an essential component of the epitranscriptome, regulating RNA metabolism and cellular functions. Several types of RNA modifications have been identified to date; they include N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), N4-acetylcytidine (ac4C), etc. RNA modifications, mediated by regulators including writers, erasers, and readers, are associated with carcinogenesis, tumor microenvironment, metabolic reprogramming, immunosuppression, immunotherapy, chemotherapy, etc. A novel perspective indicates that regulatory subunits and post-translational modifications (PTMs) are involved in the regulation of writer, eraser, and reader functions in mediating RNA modifications, tumorigenesis, and anticancer therapy. In this review, we summarize the advances made in the knowledge of different RNA modifications (especially m6A) and focus on RNA modification regulators with functions modulated by a series of factors in cancer, including regulatory subunits (proteins, noncoding RNA or peptides encoded by long noncoding RNA) and PTMs (acetylation, SUMOylation, lactylation, phosphorylation, etc.). We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer progression. Additionally, inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

The deubiquitinase USP5 promotes cholangiocarcinoma progression by stabilizing YBX1

AIMS

Ubiquitin specific peptidase 5 (USP5), a member of deubiquitinating enzymes, has garnered significant attention for its crucial role in cancer progression. This study aims to explore the role of USP5 and its potential molecular mechanisms in cholangiocarcinoma (CCA).

MAIN METHODS

To explore the effect of USP5 on CCA, gain-of-function and loss-of-function assays were conducted in human CCA cell lines RBE and HCCC9810. The CCK8, colony-forming assay, EDU, flow cytometry, transwell assay and xenografts were used to assess cell proliferation, migration and tumorigenesis. Western blot and immunohistochemistry were performed to measure the expression of related proteins. Immunoprecipitation and immunofluorescence were applied to identify the interaction between USP5 and Y box-binding protein 1 (YBX1). Ubiquitination assays and cycloheximide chase assays were carried out to confirm the effect of USP5 on YBX1.

KEY FINDINGS

We found USP5 is highly expressed in CCA tissues, and upregulated USP5 is required for the cancer progression. Knockdown of USP5 inhibited cell proliferation, migration and epithelial-mesenchymal transition (EMT) in vitro, along with suppressed xenograft tumor growth and metastasis in vivo. Mechanistically, USP5 could interact with YBX1 and stabilize YBX1 by deubiquitination in CCA cells. Additionally, silencing of USP5 hindered the phosphorylation of YBX1 at serine 102 and its subsequent translocation to the nucleus. Notably, the effect induced by USP5 overexpression in CCA cells was reversed by YBX1 silencing.

SIGNIFICANCE

Our findings reveal that USP5 is required for cell proliferation, migration and EMT in CCA by stabilizing YBX1, suggesting USP5-YBX1 axis as a promising therapeutic target for CCA.

SIAH1 facilitates the migration and invasion of gastric cancer cells through promoting the ubiquitination and degradation of RECK

Siah E3 ubiquitin protein ligase 1 (SIAH1) has been reported to participate in the development of several human cancers, including gastric cancer. However, the effect and mechanism of SIAH1 on the migration and invasion of gastric cancer cells need be further explored. Here, we first analyzed the clinical value of SIAH1 in gastric cancer, and found that SIAH1 was up-regulated in gastric cancer and associated with a poor prognosis. In addition, silencing of SIAH1 significantly inhibited the migration and invasion of gastric cancer cells through inhibiting the expression of matrix metalloproteinase-9 (MMP9), while overexpression of SIAH1 had the opposite effect. Molecularly, we provided the evidence that reversion-inducing cysteine-rich protein with Kazal motifs (RECK) was a potential substrate of SIAH1. We determined that SIAH1 could destabilize RECK through promoting its ubiquitination and degradation via proteasome pathway. We also found RECK was involved in SIAH1-regulated gastric cancer cell migration and invasion. In conclusion, SIAH1 is up-regulated in gastric cancer, which promotes the migration and invasion of gastric cancer cells through regulating RECK-MMP9 pathway.

RNA methylation-related inhibitors: Biological basis and therapeutic potential for cancer therapy

RNA methylation is widespread in nature. Abnormal expression of proteins associated with RNA methylation is strongly associated with a number of human diseases including cancer. Increasing evidence suggests that targeting RNA methylation holds promise for cancer treatment. This review specifically describes several common RNA modifications, such as the relatively well-studied N6-methyladenosine, as well as 5-methylcytosine and pseudouridine (Ψ). The regulatory factors involved in these modifications and their roles in RNA are also comprehensively discussed. We summarise the diverse regulatory functions of these modifications across different types of RNAs. Furthermore, we elucidate the structural characteristics of these modifications along with the development of specific inhibitors targeting them. Additionally, recent advancements in small molecule inhibitors targeting RNA modifications are presented to underscore their immense potential and clinical significance in enhancing therapeutic efficacy against cancer. KEY POINTS: In this paper, several important types of RNA modifications and their related regulatory factors are systematically summarised. Several regulatory factors related to RNA modification types were associated with cancer progression, and their relationships with cancer cell migration, invasion, drug resistance and immune environment were summarised. In this paper, the inhibitors targeting different regulators that have been proposed in recent studies are summarised in detail, which is of great significance for the development of RNA modification regulators and cancer treatment in the future.

Single-cell transcriptome analysis reveals the association between histone lactylation and cisplatin resistance in bladder cancer

Patients with bladder cancer (BCa) frequently acquires resistance to platinum-based chemotherapy, particularly cisplatin. This study centered on the mechanism of cisplatin resistance in BCa and highlighted the pivotal role of lactylation in driving this phenomenon. Utilizing single-cell RNA sequencing, we delineated the single-cell landscape of Bca, pinpointing a distinctive subset of BCa cells that exhibit marked resistance to cisplatin with association with glycolysis metabolism. Notably, we observed that H3 lysine 18 lactylation (H3K18la) plays a crucial role in activating the transcription of target genes by enriching in their promoter regions. Targeted inhibition of H3K18la effectively restored cisplatin sensitivity in these cisplatin-resistant epithelial cells. Furthermore, H3K18la-driven key transcription factors YBX1 and YY1 promote cisplatin resistance in BCa. These findings enhance our understanding of the mechanisms underlying cisplatin resistance, offering valuable insights for identifying novel intervention targets to overcome drug resistance in Bca.

CircRAD23B promotes proliferation and carboplatin resistance in ovarian cancer cell lines and organoids

BACKGROUND

Circular RNAs (circRNAs) are involved in the regulation of progression and drug resistance in ovarian cancer (OC). In the present study, we aimed to explore the role of circRAD23B, a newly identified circRNA, in the regulation of carboplatin-resistant OC.

METHODS

CircRAD23B expression levels were measured using qRT-PCR. The biological roles of circRAD23B were analysed using CCK-8, colony formation, EDU, flow cytometry, and cell viability assays. RNA pull-down and luciferase assays were used to investigate the interactions of circRAD23B with mRNAs and miRNAs.

RESULTS

CircRAD23B was significantly increased in carboplatin-resistant OC tissues. CircRAD23B promoted proliferation and reduced sensitivity to carboplatin in cell lines and patient-derived organoids (PDOs), consistent with in vivo findings. Mechanistically, circRAD23B acted as a molecular sponge, abrogating its inhibitory effect on Y-box binding protein 1 (YBX1) by adsorbing miR-1287-5p. Rescue experiments confirmed that the pro-proliferation and carboplatin resistance mediated by circRAD23B was partially reversed by the upregulation of miR-1287-5p.

CONCLUSIONS

Our results demonstrated, for the first time, the role of the circRAD23B/miR-1287-5p/YBX1 axis in OC progression and carboplatin resistance in cell lines, PDOs, and animal models, providing a basis for the development of targeted therapies for patients with OC.

Y-Box Binding Protein 1: Unraveling the Multifaceted Role in Cancer Development and Therapeutic Potential

Y-box binding protein 1 (YBX1), a member of the Cold Shock Domain protein family, is overexpressed in various human cancers and is recognized as an oncogenic gene associated with poor prognosis. YBX1's functional diversity arises from its capacity to interact with a broad range of DNA and RNA molecules, implicating its involvement in diverse cellular processes. Independent investigations have unveiled specific facets of YBX1's contribution to cancer development. This comprehensive review elucidates YBX1's multifaceted role in cancer across cancer hallmarks, both in cancer cell itself and the tumor microenvironment. Based on this, we proposed YBX1 as a potential target for cancer treatment. Notably, ongoing clinical trials addressing YBX1 as a target in breast cancer and lung cancer have showcased its promise for cancer therapy. The ramp up in in vitro research on targeting YBX1 compounds also underscores its growing appeal. Moreover, the emerging role of YBX1 as a neural input is also proposed where the high level of YBX1 was strongly associated with nerve cancer and neurodegenerative diseases. This review also summarized the up-to-date advanced research on the involvement of YBX1 in pancreatic cancer.

Deciphering the vital roles and mechanism of m5C modification on RNA in cancers

5-methylcytosine (m5C modification) plays an essential role in tumors, which affects different types of RNA, the expression of downstream target genes, and downstream pathways, thus participating in the tumor process. However, the effect of m5C modification on RNA in tumors and the exact mechanism have not been systematically reviewed. Therefore, we reviewed the status and sites of m5C modification, as well as the expression pattern and biological functions of m5C regulators in tumors, and further summarized the effects and regulation mechanism of m5C modification on messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), long non-coding RNA (lncRNA) and other RNA in tumors. Finally, we summed up the interaction network, potential application, and value in clinical diagnosis and treatment of tumors. Taken together, this review benefits revealing the mechanism of m5C modification in tumor progression and provides new strategies for tumor diagnosis and treatment.

E3 ubiquitin ligase Siah1 aggravates NAFLD through Scp2 ubiquitination

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver disorders and accompanied by multiple metabolic dysfunctions. Although excessive lipid accumulation in hepatocytes has been identified as a crucial mediator of NAFLD development, the underlying mechanisms are very complicated and remain largely unknown. In this study, we reported that upregulated expression of the seven in absentia homolog 1 (Siah1) in the liver exacerbated NAFLD progression. Conversely, Siah1 downregulation markedly alleviated the high fat diet-induced accumulation of hepatic fat and expression of genes related to lipid metabolism in vitro and in vivo. The mechanistic study revealed that Siah1 interacted with sterol carrier protein 2 (Scp2) and promotes its ubiquitination and degradation, suggesting that Siah1 is an important activator of Scp2 ubiquitination in the context of NAFLD. Our results demonstrated that Siah1 regulated the lipid accumulation in NAFLD by interacting with Scp2. Thus, this study presents Siah1 as a promising therapeutic target in the development of NAFLD.

RNA epigenetic modifications in ovarian cancer: The changes, chances, and challenges

Ovarian cancer (OC) is the most common female cancer worldwide. Patients with OC have high mortality because of its complex and poorly understood pathogenesis. RNA epigenetic modifications, such as m6 A, m1 A, and m5 C, are closely associated with the occurrence and development of OC. RNA modifications can affect the stability of mRNA transcripts, nuclear export of RNAs, translation efficiency, and decoding accuracy. However, there are few overviews that summarize the link between m6 A RNA modification and OC. Here, we discuss the molecular and cellular functions of different RNA modifications and how their regulation contributes to the pathogenesis of OC. By improving our understanding of the role of RNA modifications in the etiology of OC, we provide new perspectives for their use in OC diagnosis and treatment. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease.

RNA modifications in cancer

Currently, more than 170 modifications have been identified on RNA. Among these RNA modifications, various methylations account for two-thirds of total cases and exist on almost all RNAs. Roles of RNA modifications in cancer are garnering increasing interest. The research on m6A RNA methylation in cancer is in full swing at present. However, there are still many other popular RNA modifications involved in the regulation of gene expression post-transcriptionally besides m6A RNA methylation. In this review, we focus on several important RNA modifications including m1A, m5C, m7G, 2'-O-Me, Ψ and A-to-I editing in cancer, which will provide a new perspective on tumourigenesis by peeking into the complex regulatory network of epigenetic RNA modifications, transcript processing, and protein translation.

Zooming into the structure-function of RING finger proteins for anti-cancer therapeutic applications

Cancer is one of the most common and widely diagnosed diseases worldwide. With an increase in prevalence and incidence, many studies in cancer biology have been looking at the role pro-cancer proteins play. One of these proteins is the Really Interesting New Gene (RING), which has been studied extensively due to its structure and functions such as apoptosis, neddylation, and its role in ubiquitination. The RING domain is a cysteine-rich domain known to bind Cysteine and Histidine residues. It also binds two zinc ions that help stabilize the protein in various patterns, often with a 'cross-brace' topology. Different RING finger proteins have been studied and found to have suitable targets for developing anti-cancer therapeutics. These identified candidate proteins include Parkin, COP1, MDM2, BARD1, BRCA-1, PIRH2, c-CBL, SIAH1, RBX1 and RNF8. Inhibiting these candidate proteins provides opportunities for shutting down pathways associated with tumour development and metastasis.

SIAH1/CTR9 axis promotes the epithelial-mesenchymal transition of hepatocellular carcinoma

SIAH1 has been reported to participate in several human cancers, including hepatocellular carcinoma (HCC). However, the effect of SIAH1 on the epithelial-mesenchymal transition (EMT) has not been reported in HCC cells. Here, we discovered the inhibitory effect of SIAH1 on HCC cell migration and invasion, which was related with regulating EMT. Molecularly, a yeast two-hybrid experiment indicated that Cln Three Requiring 9 (CTR9) was a potential interacting protein of SIAH1, which was further verified by co-immunoprecipitation assays. Furthermore, SIAH1 inhibited the EMT of HCC cells through negatively regulating CTR9. Importantly, CTR9 was ubiquitinated and degraded by SIAH1 via the proteasome pathway in HCC cells. Additionally, it was showed that SIAH1 mainly mediated the K48-linked polyubiquitination on CTR9. Finally, the protein level of CTR9 was found to be inversely correlated with SIAH1 in human HCC tissues. Summed up all together, these findings reveal that SIAH1/CTR9 axis promotes the EMT of HCC cells and is a promising therapeutic target for HCC therapy.

SIAH1 ubiquitination-modified HMGCR inhibits lung cancer progression and promotes drug sensitivity through cholesterol synthesis

BACKGROUNDS

Lung cancer is one of the most frequently diagnosed cancers and the leading cause of cancer-related deaths worldwide. Deep understanding of chemoresistance will lead to remarkable progress in lung cancer treatment strategy. Cholesterol accumulation was associated with cisplatin resistance in lung cancer treatment. And we found the degree of cisplatin resistance was correlated with the expression of the cholesterol synthesis HMGCR.

METHODS

We analyzed a group of 42 lung cancer patients who received cisplatin treatment after lung resection surgery. The expression of HMGCR and its correlation with cholesterol in lung cancer cell lines were determined by qRT-PCR and ELISA analyses. We focus on the function and mechanism of HMGCR in lung cancer and reveal that knockdown of HMGCR expression inhibits the proliferation, colony formation, and migration of lung cancer cell lines in vitro or in vivo and dramatically enhances the efficacy of cisplatin.

RESULTS

Through mechanism studies, we illustrate that SIAH1, an E3 ubiquitin-protein ligase, ubiquitination modifies HMGCR and inhibits efflux protein activity via regulating cholesterol synthesis. In vivo experiments showed that SIAH1 overexpression or using HMGCR knockdown retard tumor growth and enhanced the efficacy of cisplatin. In summary, HMGCR affects cholesterol metabolism by regulating key enzymes in cholesterol synthesis, thereby reducing drug sensitivity.

CONCLUSION

This study indicates that lung cancer patients with lower HMGCR levels may lead to a better prognosis and provide a potential treatment by SIAH1 overexpression for lung cancer patients with cisplatin resistance.

RNA Modifications Meet Tumors

RNA modifications occur through the whole process of gene expression regulation, including transcription, translation, and post-translational processes. They are closely associated with gene expression, RNA stability, and cell cycle. RNA modifications in tumor cells play a vital role in tumor development and metastasis, changes in the tumor microenvironment, drug resistance in tumors, construction of tumor cell-cell "internet", etc. Several types of RNA modifications have been identified to date and have various effects on the biological characteristics of different tumors. In this review, we discussed the function of RNA modifications, including N 6-methyladenine (m6A), 5-methylcytosine (m5C), N 7-methyladenosine (m7G), N 1-methyladenosine (m1A), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I), in the microenvironment and therapy of solid and liquid tumors.

Siah1 promotes the proliferation of NSCLC cells through ubiquitinating and stabilizing Notch1

Seven in absentia homolog 1 (Siah1) has been shown plays important roles in the pathogenesis and development of multiple cancers. However, the functions and mechanisms of Siah1 in non-small cell lung cancer (NSCLC) remain unclear. In our study, we found that knock down of Siah1 could inhibit the proliferation of NSCLC cells, while over-expression of Siah1 had the opposite effects. Molecularly, the bioinformatics analysis determined that notch receptor 1 (Notch1) might be the potential target of Siah1. Subsequently, we identified that Siah1 acted as an E3 ligase to promote the ubiquitination and stabilization of Notch1 through the proteasome pathway. Furthermore, the results showed that the Siah1 expression was directly correlated with CTR9 in human NSCLC tissues. Finally, Siah1 could promote Akt phosphorylation through regulating Notch1, thus promoting the proliferation of NSCLC cells. In conclusion, our study demonstrated that Siah1 acts as an oncogene, can ubiquitinate and stabilize Notch1 by proteasome pathway, which promotes Akt phosphorylation and ultimately leads to NSCLC cell proliferation.

YB-1 as an Oncoprotein: Functions, Regulation, Post-Translational Modifications, and Targeted Therapy

Y box binding protein 1 (YB-1) is a protein with a highly conserved cold shock domain (CSD) that also belongs to the family of DNA- and RNA-binding proteins. YB-1 is present in both the nucleus and cytoplasm and plays versatile roles in gene transcription, RNA splicing, DNA damage repair, cell cycle progression, and immunity. Cumulative evidence suggests that YB-1 promotes the progression of multiple tumor types and serves as a potential tumor biomarker and therapeutic target. This review comprehensively summarizes the emerging functions, mechanisms, and regulation of YB-1 in cancers, and further discusses targeted strategies.