Silencing MYH9 blocks HBx-induced GSK3β ubiquitination and degradation to inhibit tumor stemness in hepatocellular carcinoma

MYH9: A key protein involved in tumor progression and virus-related diseases

The myosin heavy chain 9 (MYH9) gene encodes the heavy chain of non-muscle myosin IIA (NMIIA), which belongs to the myosin II subfamily of actin-based molecular motors. Previous studies have demonstrated that abnormal expression and mutations of MYH9 were correlated with MYH9-related diseases and tumors. Furthermore, earlier investigations identified MYH9 as a tumor suppressor. However, subsequent research revealed that MYH9 promoted tumorigenesis, progression and chemoradiotherapy resistance. Note-worthily, MYH9 has also been linked to viral infections, like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Epstein-Barr virus, and hepatitis B virus, as a receptor or co-receptor. In addition, MYH9 promotes the development of hepatocellular carcinoma by interacting with the hepatitis B virus-encoding X protein. Finally, various findings highlighted the role of MYH9 in the development of these illnesses, especially in tumors. This review summarizes the involvement of the MYH9-regulated signaling network in tumors and virus-related diseases and presents possible drug interventions on MYH9, providing insights for the use of MYH9 as a therapeutic target for tumors and virus-mediated diseases.

Exploring the regulatory role of Linc00893 in asthenozoospermia: Insights into sperm motility and SSC viability

The role of long intergenic noncoding RNA 00893 (Linc00893) in asthenozoospermia (AS) and its impact on sperm motility remains unclear The present study explored the effect of Linc00893 on AS, specifically its effect on sperm motility and its relationship with spermatogonial stem cell (SSC) vitality and myosin heavy chain 9 (MYH9) protein expression. Linc00893 expression was analyzed in semen samples using reverse transcription‑quantitative PCR, revealing a significant downregulation in samples from individuals with AS compared with those from healthy subjects. This downregulation was found to be negatively correlated with parameters of sperm motility. To further understand the role of Linc00893, small interfering RNA was used to knockdown its expression in SSCs. This knockdown led to a marked decrease in cell vitality and an increase in apoptosis. Notably, Linc00893 knockdown was shown to inhibit MYH9 expression by competitively binding with microRNA‑107, a finding verified by dual‑luciferase reporter and RNA immunoprecipitation assays. Furthermore, using the GSE160749 dataset from the Gene Expression Omnibus database, it was revealed that MYH9 protein expression was downregulated in AS samples. Subsequently, lentiviral vectors were constructed to induce overexpression of MYH9, which in turn reduced SSC apoptosis and counteracted the apoptosis triggered by Linc00893 knockdown. In conclusion, the present study identified the role of Linc00893 in AS, particularly its regulatory impact on sperm motility, SSC vitality and MYH9 expression. These findings may provide information on the potential regulatory mechanisms in AS development, and identify Linc00893 and MYH9 as possible targets for diagnosing and treating AS‑related disorders.

Mechanistic insights into aniline-induced liver injury: Role of the mmu_circ_26984/Myh9/NLRP3 axis and modulation by N-acetylcysteine

Aniline is a widely used chemical. Chronic or high-dose exposure to aniline can lead to hepatocellular damage. Although the hepatic pathogenicity of aniline has been established in previous studies, studies involving pathogenic genes during aniline-induced liver injury are limited. Our study first discovered and identified the role and mechanism underlying a new circRNA mmu_circ_26984 in aniline-induced chemical liver injury. Further, we discuss the protective effect of N-acetylcysteine (NAC) in this pathway. After constructing in vitro and in vivo models of aniline treatment, we screened the circRNA with significant differences in expression in AML12 cells from control and aniline-treated groups by circRNA microarray analysis. Next, using RNA pulldown, liquid chromatography-mass spectrometry (LC-MS), and RNA immunoprecipitation, we analyzed the relationship between mmu_circ_26984 and myosin heavy chain 9 (Myh9). Subsequently, we determined the specific mechanism of action of mmu_circ_26984 and Myh9 in aniline-induced liver injury and the protective effect of NAC against aniline-induced liver injury process using Cell Counting Kit-8, Western blot, RNA extraction, a reverse transcription quantitative polymerase chain reaction (RT-qPCR), fluorescence in situ hybridization, immunohistochemistry, and immunofluorescence. The expression of mmu_circ_26984 was significantly increased in liver tissues and AML12 cells of aniline-treated mice compared with the control group. This high expression of mmu_circ_26984 increased the expression of injury-related inflammatory factors, such as NLRP3, Caspase-1, IL-18, and IL-1β in vivo and ex vivo, which exacerbated the level of liver injury. The interaction of mmu_circ_26984 with Myh9 also affected the course of liver injury. Mmu_circ_26984 overexpression and reduced treatment affected the levels of Myh9 expression in AML12 cells, as well as downstream inflammatory factors associated with injury, such as NLRP3. In addition, NAC reduced the process of liver injury mediated by the mmu_circ_26984/Myh9/NLRP3 axis. In conclusion, mmu_circ_26984 is a potential molecular marker and therapeutic target in the process of aniline-induced liver injury that can mediate aniline-exposure-induced liver injury via modulation of the mmu_circ_26984/Myh9/NLRP3 axis, and NAC can effectively attenuate the effect of this liver injury.

USP22-JMJD8 axis promotes Lenvatinib resistance in hepatocellular carcinoma

Lenvatinib is the first-line treatment for patients with advanced HCC, however, drug resistance cannot be avoided during the treatment process, limiting the efficacy of Lenvatinib. We constructed drug-resistant HCC cells by gradually increasing the dose of Lenvatinib. The study found for the first time that USP22 and JMJD8 are upregulated in Lenvatinib resistant HCC cells. In addition, the expression level of stemness related proteins (CD133, C-MYC, BMI1, β-CATENIN) in drug-resistant cells was higher than that in wild-type HCC cells. Knockdown of USP22 in drug-resistant HCC cells could reduce the invasion, migration and stemness of cells. Next, we explored the mechanism of USP22 in Lenvatinib resistance of HCC cells. Under the treatment of Lenvatinib, USP22 knockdown inhibited the cell viability of drug-resistant HCC cells and promoted the apoptosis of drug-resistant cells. Animal experiments in nude mice further demonstrated the important role of USP22 in inducing the resistance of HCC to Lenvatinib in vivo. More importantly, we found that USP22 and JMJD8 constitute a functional axis regulating the drug resistance of Lenvatinib in HCC. In the rescue experiment, the overexpression of JMJD8 could reduce the apoptosis induced by USP22 knockdown. In general, this study shows that USP22-JMJD8 is a drug design target for the mechanism of Lenvatinib resistance in HCC, which may improve the long-term efficacy of Lenvatinib.

Role of hepatitis B virus non-structural protein HBx on HBV replication, interferon signaling, and hepatocarcinogenesis

Hepatitis B, a global health concern caused by the hepatitis B virus (HBV), infects nearly 2 billion individuals worldwide, as reported by the World Health Organization (WHO). HBV, a hepatotropic DNA virus, predominantly targets and replicates within hepatocytes. Those carrying the virus are at increased risk of liver cirrhosis and hepatocellular carcinoma, resulting in nearly 900,000 fatalities annually. The HBV X protein (HBx), encoded by the virus's open reading frame x, plays a key role in its virulence. This protein is integral to viral replication, immune modulation, and liver cancer progression. Despite its significance, the precise molecular mechanisms underlying HBx remain elusive. This review investigates the HBx protein's roles in HBV replication, interferon signaling regulation, and hepatocellular carcinoma progression. By understanding the complex interactions between the virus and its host mediated by HBx, we aim to establish a solid foundation for future research and the development of HBx-targeted therapeutics.

ACTN1 promotes HNSCC tumorigenesis and cisplatin resistance by enhancing MYH9-dependent degradation of GSK-3β and integrin β1-mediated phosphorylation of FAK

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignant tumors globally. Understanding the molecular basis of tumor progression and drug resistance can offer innovative strategies to enhance clinical outcomes for HNSCC patients.

METHODS

The cytoskeletal remodeling genes associated with cisplatin resistance were screened using a PCR array. The role of alpha-actinin 1 (ACTN1) in modulating cisplatin resistance and tumorigenesis in HNSCC was evaluated both in vitro and in vivo. Co-immunoprecipitation (Co-IP), IP-mass spectrometry (MS), western blotting, dual-luciferase assay, and bioinformatics analysis were performed to elucidate the underlying mechanisms involved.

RESULTS

Our study identifies ACTN1 as a crucial contributor to cisplatin resistance and tumorigenesis in HNSCC, as evidenced across cellular, animal, and patient-derived xenograft models. From a clinical perspective, overexpression of ACTN1 significantly correlates with a suboptimal response to neoadjuvant chemotherapy and reduced overall survival in HNSCC patients. Mechanistically, ACTN1 predominantly activates β-catenin-mediated signaling by promoting the interaction between myosin heavy chain 9 (MYH9) and GSK-3β, leading to the ubiquitin-dependent degradation of GSK-3β. ACTN1 also interacts with integrin β1, subsequently activating the FAK/PI3K/AKT pathway, providing an additional avenue for the activation of β-catenin signaling. Our study also unveils that the β-catenin/c-Myc axis transcriptionally regulates ACTN1, thereby creating a positive feedback loop promoting HNSCC tumorigenesis and drug resistance.

CONCLUSIONS

These insights underscore the novel mechanisms that highlight ACTN1's pivotal role in driving HNSCC progression and resistance to chemotherapy, suggesting ACTN1 as a promising therapeutic target in HNSCC management.

Transcriptional co-activators: emerging roles in signaling pathways and potential therapeutic targets for diseases

Specific cell states in metazoans are established by the symphony of gene expression programs that necessitate intricate synergic interactions between transcription factors and the co-activators. Deregulation of these regulatory molecules is associated with cell state transitions, which in turn is accountable for diverse maladies, including developmental disorders, metabolic disorders, and most significantly, cancer. A decade back most transcription factors, the key enablers of disease development, were historically viewed as 'undruggable'; however, in the intervening years, a wealth of literature validated that they can be targeted indirectly through transcriptional co-activators, their confederates in various physiological and molecular processes. These co-activators, along with transcription factors, have the ability to initiate and modulate transcription of diverse genes necessary for normal physiological functions, whereby, deregulation of such interactions may foster tissue-specific disease phenotype. Hence, it is essential to analyze how these co-activators modulate specific multilateral processes in coordination with other factors. The proposed review attempts to elaborate an in-depth account of the transcription co-activators, their involvement in transcription regulation, and context-specific contributions to pathophysiological conditions. This review also addresses an issue that has not been dealt with in a comprehensive manner and hopes to direct attention towards future research that will encompass patient-friendly therapeutic strategies, where drugs targeting co-activators will have enhanced benefits and reduced side effects. Additional insights into currently available therapeutic interventions and the associated constraints will eventually reveal multitudes of advanced therapeutic targets aiming for disease amelioration and good patient prognosis.

FGFR families: biological functions and therapeutic interventions in tumors

There are five fibroblast growth factor receptors (FGFRs), namely, FGFR1-FGFR5. When FGFR binds to its ligand, namely, fibroblast growth factor (FGF), it dimerizes and autophosphorylates, thereby activating several key downstream pathways that play an important role in normal physiology, such as the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase (PI3K)/AKT, phospholipase C gamma/diacylglycerol/protein kinase c, and signal transducer and activator of transcription pathways. Furthermore, as an oncogene, FGFR genetic alterations were found in 7.1% of tumors, and these alterations include gene amplification, gene mutations, gene fusions or rearrangements. Therefore, FGFR amplification, mutations, rearrangements, or fusions are considered as potential biomarkers of FGFR therapeutic response for tyrosine kinase inhibitors (TKIs). However, it is worth noting that with increased use, resistance to TKIs inevitably develops, such as the well-known gatekeeper mutations. Thus, overcoming the development of drug resistance becomes a serious problem. This review mainly outlines the FGFR family functions, related pathways, and therapeutic agents in tumors with the aim of obtaining better outcomes for cancer patients with FGFR changes. The information provided in this review may provide additional therapeutic ideas for tumor patients with FGFR abnormalities.

Targeting MYH9 represses USP14-mediated NAP1L1 deubiquitination and cell proliferation in glioma

Myosin heavy chain 9 (MYH9) plays an important role in a number of diseases. Nevertheless, the function of MYH9 in glioma is unclear. The present research aimed to investigate the role of MYH9 in glioma and determine whether MYH9 is involved in the temozolomide chemoresistance of glioma cells. Our results showed that MYH9 increased the proliferation and temozolomide resistance of glioma cells. The mechanistic experiments showed that the binding of MYH9 to NAP1L1, a potential promoter of tumor proliferation, inhibited the ubiquitination and degradation of NAP1L1 by recruiting USP14. Upregulation of NAP1L1 increased its binding with c-Myc and activated c-Myc, which induced the expression of CCND1/CDK4, promoting glioma cell temozolomide resistance and proliferation. Additionally, we found that MYH9 upregulation was strongly related to patient survival and is therefore a negative factor for patients with glioma. Altogether, our results show that MYH9 plays a role in glioma progression by regulating NAP1L1 deubiquitination. Thus, targeting MYH9 is a potential therapeutic strategy for the clinical treatment of glioma in the future.

Dimeric oxyberberine CT4-1 targets LINC02331 to induce cytotoxicity and inhibit chemoresistance via suppressing Wnt/β-catenin signaling in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a type of cancer characterized by high recurrence rates. Overcoming chemoresistance can reduce HCC recurrence and improve patients' prognosis. This work aimed to identify HCC chemoresistance-associated long non-coding RNA (lncRNA) and find an effective drug targeting the identified lncRNA for ameliorating the chemoresistance. In this investigation, bioinformatics analysis based on The Cancer Genome Atlas revealed a new chemoresistance index and suggested LINC02331 as an HCC chemoresistance and patients' prognosis-associated lncRNA that served as an independent prognostic indicator. Moreover, LINC02331 promoted DNA damage repair, DNA replication, and epithelial-mesenchymal transition as well as attenuated cell cycle arrest and apoptosis through regulating Wnt/β-catenin signaling, thus stimulating HCC resistance to cisplatin cytotoxicity, proliferation, and metastasis. Interestingly, we developed a novel oxidative coupling approach to synthesize a dimeric oxyberberine CT4-1, which exerted superior anti-HCC activities without obvious side effects measured by in vivo mice model and could downregulate LINC02331 mice model and could downregulate LINC02331 to mitigate LINC02331-induced HCC progression by suppressing Wnt/β-catenin signaling. RNA sequencing analyses verified the involvement of CT4-1-affected differential expression genes in dysregulated pathways and processes, including Wnt, DNA damage repair, cell cycle, DNA replication, apoptosis, and cell adhesion molecules. Furthermore, CT4-1 was demonstrated to be an effective cytotoxic drug in ameliorating HCC patients' prognosis with a prediction model constructed based on RNA-sequencing data from CT4-1-treated cancer cells and public cancer database. In summary, HCC chemoresistance-associated LINC02331 independently predicted poor patients' prognosis and enhanced HCC progression by promoting resistance to cisplatin cytotoxicity, proliferation, and metastasis. Targeting LINC02331 by the dimeric oxyberberine CT4-1 that exhibited synergistic cytotoxicity with cisplatin could alleviate HCC progression and improve patients' prognosis. Our study identified LINC02331 as an alternative target and suggested CT4-1 as an effective cytotoxic drug in HCC treatment.

Regulatory network and targeted interventions for CCDC family in tumor pathogenesis

CCDC (coiled-coil domain-containing) is a coiled helix domain that exists in natural proteins. There are about 180 CCDC family genes, encoding proteins that are involved in intercellular transmembrane signal transduction and genetic signal transcription, among other functions. Alterations in expression, mutation, and DNA promoter methylation of CCDC family genes have been shown to be associated with the pathogenesis of many diseases, including primary ciliary dyskinesia, infertility, and tumors. In recent studies, CCDC family genes have been found to be involved in regulation of growth, invasion, metastasis, chemosensitivity, and other biological behaviors of malignant tumor cells in various cancer types, including nasopharyngeal carcinoma, lung cancer, colorectal cancer, and thyroid cancer. In this review, we summarize the involvement of CCDC family genes in tumor pathogenesis and the relevant upstream and downstream molecular mechanisms. In addition, we summarize the potential of CCDC family genes as tumor therapy targets. The findings discussed here help us to further understand the role and the therapeutic applications of CCDC family genes in tumors.

MYH10 Combines with MYH9 to Recruit USP45 by Deubiquitinating Snail and Promotes Serous Ovarian Cancer Carcinogenesis, Progression, and Cisplatin Resistance

The poor prognosis of serous ovarian cancer (SOC) is due to its high invasive capacity and cisplatin resistance of SOC cells, whereas the molecular mechanisms remain poorly understood. In the present study, the expression and function of non-muscle myosin heavy chain IIB (MYH10) in SOC are identified by immunohistochemistry, in vitro, and in vivo studies, respectively. The mechanism of MYH10 is demonstrated by co-immunoprecipitation, GST pull-down, confocal laser assays, and so on. The results show that the knockdown of MYH10 suppressed SOC cell proliferation, migration, invasion, metastasis, and cisplatin resistance both in vivo and in vitro. Further studies confirm that the MYH10 protein functional domain combines with non-muscle myosin heavy chain IIA (MYH9) to recruit the deubiquitinating enzyme Ubiquitin-specific proteases 45 and deubiquitinates snail to inhibit snail degradation, eventually promoting tumorigenesis, progression, and cisplatin resistance in SOC. In clinical samples, MYH10 expression is significantly elevated in SOC samples compared to the paratumor samples. And the expression of MYH10 is positively correlated with MYH9 expression. MYH10+/MYH9+ co-expression is an independent prognostic factor for predicting SOC patient survival. These findings uncover a key role of the MYH10-MYH9-snail axis in SOC carcinogenesis, progression, and cisplatin resistance, and provide potential novel therapeutic targets for SOC intervention.

Combined GSK-3β and MEK inhibitors modulate the stemness and radiotherapy sensitivity of cervical cancer stem cells through the Wnt signaling pathway

Cancer stem cells (CSCs) are the basis of cancer and lead to the recurrence and metastasis of cervical cancer. The aim of this study was to investigate the effects of antineoplastic agents on the stemness and radiotherapy sensitivity of cervical CSCs. Side population (SP) and non-side population (NSP) cells from the SiHa cervical cancer cell line were separated using flow cytometry. The cell spheroidization, proliferation, and subcutaneous tumor formation abilities of SP cells were stronger than those of NSP cells, and cervical CSC marker expressions increased in SP cells. The proliferation, anti-apoptosis and migration of SP cells under ionizing radiation were higher than those of SiHa cells. GSK-3β and/or MEK inhibitors can increase the proliferation, migration and anti-apoptosis of SP cells, and CSC marker expressions. The Wnt pathway inhibitor decreased CSC stemness maintenance by combination of GSK-3β and MEK inhibitors. Injection of GSK-3β and MEK inhibitors under ionizing radiation promoted tumor growth and activated downstream factor expressions in the Wnt signaling pathway in vivo. This study demonstrated that combining GSK-3β and MEK inhibitors can activate Wnt signaling pathway in cervical CSCs, thereby affecting their stemness maintenance and radiotherapy sensitivity.

TM4SF1 upregulates MYH9 to activate the NOTCH pathway to promote cancer stemness and lenvatinib resistance in HCC

TM4SF1, a member of the transmembrane 4 superfamily, is crucial for both healthy and malignant human tissues. The significant function of TM4SF1 in the incidence and progression of cancer has been widely recognized in recent years. Although some achievements have been made in the study of TM4SF1, the effect of TM4SF1 on cancer stemness in hepatocellular carcinoma (HCC) and its molecular basis are yet to be reported. We found through abundant in vitro and in vivo experiments which the expression of TM4SF1 was positively correlated with the progression and cancer stemness of HCC. We identified the downstream protein MYH9 of TM4SF1 and its final regulatory target NOTCH pathway using bioinformatics analysis and protein mass spectrometry. We cultivated a Lenvatinib-resistant strain from HCC cells to examine the relationship between cancer stemness and tumor drug resistance. The study confirmed that TM4SF1 could regulate the NOTCH pathway by upregulating MYH9, thus promoting cancer stemness and Lenvatinib resistance in HCC. This study not only provided a new idea for the pathogenesis of HCC but also confirmed that TM4SF1 might become a new intervention point to improve the clinical efficacy of Lenvatinib in treating HCC.

Role of β-Catenin Activation in the Tumor Immune Microenvironment and Immunotherapy of Hepatocellular Carcinoma

Recently, the therapeutic combination of atezolizumab and bevacizumab was widely used to treat advanced hepatocellular carcinoma (HCC). According to recent clinical trials, immune checkpoint inhibitors (ICIs) and molecular target agents are expected to be key therapeutic strategies in the future. Nonetheless, the mechanisms underlying molecular immune responses and immune evasion remain unclear. The tumor immune microenvironment plays a vital role in HCC progression. The infiltration of CD8-positive cells into tumors and the expression of immune checkpoint molecules are key factors in this immune microenvironment. Specifically, Wnt/β catenin pathway activation causes "immune exclusion", associated with poor infiltration of CD8-positive cells. Some clinical studies suggested an association between ICI resistance and β-catenin activation in HCC. Additionally, several subclassifications of the tumor immune microenvironment were proposed. The HCC immune microenvironment can be broadly divided into inflamed class and non-inflamed class, with several subclasses. β-catenin mutations are important factors in immune subclasses; this may be useful when considering therapeutic strategies as β-catenin activation may serve as a biomarker for ICI. Various types of β-catenin modulators were developed. Several kinases may also be involved in the β-catenin pathway. Therefore, combinations of β-catenin modulators, kinase inhibitors, and ICIs may exert synergistic effects.

SAMD9 Promotes Postoperative Recurrence of Esophageal Squamous Cell Carcinoma by Stimulating MYH9-Mediated GSK3β/β-Catenin Signaling

Recurrence is a challenge to survival after the initial treatment of esophageal squamous cell carcinoma (ESCC). But, its mechanism remains elusive and there are currently no biomarkers to predict postoperative recurrence. Here, the possibility of sterile alpha motif domain-containing protein 9 (SAMD9) as a predictor of postoperative recurrence of ESCC is evaluated and the molecular mechanisms by which SAMD9 promotes ESCC recurrence are elucidated. The authors found that the high level of SAMD9 is correlated with postoperative recurrence and poor prognosis of ESCC. Overexpression of SAMD9 promotes tumor stemness, angiogenesis, and EMT, while downregulation of SAMD9 reduced these phenotypes. Mechanistically, it is found that SAMD9 stimulated ubiquitination-mediated glycogen synthase kinase-3 beta (GSK-3β) degradation by interaction with myosin-9 (MYH9) and TNF receptor-associated factor 6 (TRAF6), which in turn activated Wnt/β-catenin pathway. Further, the authors demonstrated that silencing SAMD9 inhibited lung metastasis and tumor formation in vivo. Finally, the authors found that silencing MYH9 or β-catenin, or overexpressing GSK-3β inhibited SAMD9-stimulated ESCC cell stemness, EMT, angiogenesis, metastasis, and tumorigenicity. Together, the findings indicate that the SAMD9/MYH9/GSK3β/β-catenin axis promotes ESCC postoperative recurrence and that SAMD9 is a crucial target for ESCC therapy. Additionally, SAMD9 has the potential as a predictor of postoperative recurrence in ESCC.

Immunity-related long noncoding RNA WDFY3-AS2 inhibited cell proliferation and metastasis through Wnt/β-catenin signaling in oral squamous cell carcinoma

OBJECTIVE

Long noncoding RNA WDFY3-AS2 has been shown to play dual roles in the modulation of cancer progression. This study aimed at clarifying the biological role of WDFY3-AS2 as well as the association between WDFY3-AS2 expression, β-catenin expression, and OSCC immunity in oral squamous cell carcinoma (OSCC).

DESIGN

Bioinformatics analyses, CCK8, EdU, wound healing, transwell, RT-qPCR, western blot, immunofluorescence, in situ hybridization, and immunohistochemistry assays were adopted for exploring the role of WDFY3-AS2 in OSCC.

RESULTS

Bioinformatics analyses showed that WDFY3-AS2 conferred a poor prognosis for OSCC patients. Further analyses identified WDFY3-AS2 as an independent prognostic indicator for OSCC. Moreover, silencing WDFY3-AS2 inhibits OSCC cell proliferation, migration and invasion. Gene set enrichment analysis indicated that WDFY3-AS2 participated in the regulation of Wnt signaling. In addition, WDFY3-AS2 expression was positively associated with β-catenin mRNA levels, the key component of Wnt signaling. Interestingly, WDFY3-AS2 knockdown inhibited β-catenin expression and nuclear translocation, thus suppressing OSCC progression through Wnt signaling. Furthermore, WDFY3-AS2 expression correlated with an immunosuppressive phenotype in the tumor immune microenvironment. In situ hybridization and immunohistochemistry verified that WDFY3-AS2 was positively associated with total and nuclear β-catenin protein levels and negatively associated with CD4 expression.

CONCLUSIONS

This study demonstrates that the immunity-associated WDFY3-AS2 augments OSCC proliferation and metastasis through Wnt/β-catenin signaling and may serve as a novel treatment target and a new prognostic factor for OSCC.

Phosphorylation of UHRF2 affects malignant phenotypes of HCC and HBV replication by blocking DHX9 ubiquitylation

Hepatitis B virus (HBV) infection is one of main contributors to poor prognosis and rapid progression of hepatocellular cancer (HCC). We previously identified the important role of the phosphorylation of ubiquitin-like with PHD and ring finger domains (UHRF2) in HBV-associated HCC. In this study we identify upregulated UHRF2 protein levels in HBV-associated HCC cells and tissues. UHRF2 overexpression promotes the viability, proliferation, migration and invasiveness of HBV-positive HCC cell lines, and enhances HBV DNA replication. To obtain a comprehensive understanding of the interaction networks of UHRF2 and their underlying mechanism, this study suggests that UHRF2 facilitates the ubiquitin-proteasome-mediated proteolysis of DExD/H (Asp-Glu-Ala-His) -box helicase enzyme 9 (DHX9). However, phosphorylation of UHRF2 by HBx at S643 inhibits E3 ubiquitin ligase activity of UHRF2 and improves DHX9 protein stability. Furthermore, results suggest that HBx promotes phosphorylation of UHRF2 by the ETS1-CDK2 axis through the downregulation of miR-222-3p in HBV-associated HCC specimens and cells. Our findings suggest that HBx-induced phosphorylation of UHRF2 S643 acts as a "switch" in HBV-associated HCC oncogenesis, activating the positive feedback between phosphorylated UHRF2 and HBV, provide evidence that UHRF2 is a new regulator and a potential prognostic indicator of poor prognosis for HBV-associated HCC.

Inferring cancer common and specific gene networks via multi-layer joint graphical model

Cancer is a complex disease caused primarily by genetic variants. Reconstructing gene networks within tumors is essential for understanding the functional regulatory mechanisms of carcinogenesis. Advances in high-throughput sequencing technologies have provided tremendous opportunities for inferring gene networks via computational approaches. However, due to the heterogeneity of the same cancer type and the similarities between different cancer types, it remains a challenge to systematically investigate the commonalities and specificities between gene networks of different cancer types, which is a crucial step towards precision cancer diagnosis and treatment. In this study, we propose a new sparse regularized multi-layer decomposition graphical model to jointly estimate the gene networks of multiple cancer types. Our model can handle various types of gene expression data and decomposes each cancer-type-specific network into three components, i.e., globally shared, partially shared and cancer-type-unique components. By identifying the globally and partially shared gene network components, our model can explore the heterogeneous similarities between different cancer types, and our identified cancer-type-unique components can help to reveal the regulatory mechanisms unique to each cancer type. Extensive experiments on synthetic data illustrate the effectiveness of our model in joint estimation of multiple gene networks. We also apply our model to two real data sets to infer the gene networks of multiple cancer subtypes or cell lines. By analyzing our estimated globally shared, partially shared, and cancer-type-unique components, we identified a number of important genes associated with common and specific regulatory mechanisms across different cancer types.

Hepatitis B virus infection: An insight into the clinical connection and molecular interaction between hepatitis B virus and host extrahepatic cancer risk

The evidence for chronic hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) occurrence is well established. The hepatocyte epithelium carcinogenesis caused by HBV has been investigated and reviewed in depth. Nevertheless, recent findings from preclinical and observational studies suggested that chronic HBV infection is equally important in extrahepatic cancer occurrence and survival, specifically gastrointestinal system-derived cancers. Immune microenvironment changes (immune-suppressive cytokine infiltration), epigenetic modification (N6-methyladenosine), molecular signaling pathways (PI3K-Akt and Wnt), and serum biomarkers such as hepatitis B virus X (HBx) protein are potential underlying mechanisms in chronic HBV infection-induced extrahepatic cancers. This narrative review aimed to comprehensively summarize the most recent advances in evaluating the association between chronic HBV infection and extrahepatic cancer risk and explore the potential underlying molecular mechanisms in the carcinogenesis induction of extrahepatic cancers in chronic HBV conditions.

Characteristic gene expression in the liver monocyte-macrophage-DC system is associated with the progression of fibrosis in NASH

Background

The monocyte-macrophage-dendritic cell (DC) (MMD) system exerts crucial functions that may modulate fibrogenesis in nonalcoholic steatohepatitis (NASH). In this study, we explored the cell characteristics, distribution and developmental trajectory of the liver MMD system in NASH mice with fibrosis and clarified characteristic genes of the MMD system involved in liver fibrosis progression in NASH mice and patients.

Methods

Single cells in liver tissue samples from NASH and normal mice were quantified using single-cell RNA sequencing (scRNA-seq) analysis. Differentially expressed genes (DEGs) in the MMD system by pseudotime analysis were validated by tyramide signal amplification (TSA)-immunohistochemical staining (IHC) and analyzed by second harmonic generation (SHG)/two-photon excitation fluorescence (TPEF).

Results

Compared with control mice, there were increased numbers of monocytes, Kupffer cells, and DCs in two NASH mouse models. From the transcriptional profiles of these single cells, we identified 8 monocyte subsets (Mono1-Mono8) with different molecular and functional properties. Furthermore, the pseudotime analysis showed that Mono5 and Mono6 were at the beginning of the trajectory path, whereas Mono2, Mono4, Kupffer cells and DCs were at a terminal state. Genes related to liver collagen production were at the late stage of this trajectory path. DEGs analysis revealed that the genes Fmnl1 and Myh9 in the MMD system were gradually upregulated during the trajectory. By TSA-IHC, the Fmnl1 and Myh9 expression levels were increased and associated with collagen production and fibrosis stage in NASH mice and patients.

Conclusions

Our transcriptome data provide a novel landscape of the MMD system that is involved in advanced NASH disease status. Fmnl1 and Myh9 expression in the MMD system was associated with the progression of NASH fibrosis.

Longitudinal Plasma Proteomics-Derived Biomarkers Predict Response to MET Inhibitors for MET-Dysregulated NSCLC

MET inhibitors have shown promising efficacy for MET-dysregulated non-small cell lung cancer (NSCLC). However, quite a few patients cannot benefit from it due to the lack of powerful biomarkers. This study aims to explore the potential role of plasma proteomics-derived biomarkers for patients treated with MET inhibitors using mass spectrometry. We analyzed the plasma proteomics from patients with MET dysregulation (including MET amplification and MET overexpression) treated with MET inhibitors. Thirty-three MET-dysregulated NSCLC patients with longitudinal 89 plasma samples were included. We classified patients into the PD group and non-PD group based on clinical response. The baseline proteomic profiles of patients in the PD group were distinct from those in the non-PD group. Through protein screening, we found that a four-protein signature (MYH9, GNB1, ALOX12B, HSD17B4) could predict the efficacy of patients treated with MET inhibitors, with an area under the curve (AUC) of 0.93, better than conventional fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC) tests. In addition, combining the four-protein signature with FISH or IHC test could also reach higher predictive performance. Further, the combined signature could predict progression-free survival for MET-dysregulated NSCLC (p < 0.001). We also validated the performance of the four-protein signature in another cohort of plasma using an enzyme-linked immunosorbent assay. In conclusion, the four plasma protein signature (MYH9, GNB1, ALOX12B, and HSD17B4 proteins) might play a substitutable or complementary role to conventional MET FISH or IHC tests. This exploration will help select patients who may benefit from MET inhibitors.

NAFLD and HBV interplay - related mechanisms underlying liver disease progression

Non-alcoholic fatty liver disease (NAFLD) and Hepatitis B virus infection (HBV) constitute common chronic liver diseases with worldwide distribution. NAFLD burden is expected to grow in the coming decade, especially in western countries, considering the increased incidence of diabetes and obesity. Despite the organized HBV vaccinations and use of anti-viral therapies globally, HBV infection remains endemic and challenging public health issue. As both NAFLD and HBV have been associated with the development of progressive fibrosis, cirrhosis and hepatocellular carcinoma (HCC), the co-occurrence of both diseases has gained great research and clinical interest. The causative relationship between NAFLD and HBV infection has not been elucidated so far. Dysregulated fatty acid metabolism and lipotoxicity in NAFLD disease seems to initiate activation of signaling pathways that enhance pro-inflammatory responses and disrupt hepatocyte cell homeostasis, promoting progression of NAFLD disease to NASH, fibrosis and HCC and can affect HBV replication and immune encountering of HBV virus, which may further have impact on liver disease progression. Chronic HBV infection is suggested to have an influence on metabolic changes, which could lead to NAFLD development and the HBV-induced inflammatory responses and molecular pathways may constitute an aggravating factor in hepatic steatosis development. The observed altered immune homeostasis in both HBV infection and NAFLD could be associated with progression to HCC development. Elucidation of the possible mechanisms beyond HBV chronic infection and NAFLD diseases, which could lead to advanced liver disease or increase the risk for severe complications, in the case of HBV-NAFLD co-existence is of high clinical significance in the context of designing effective therapeutic targets.

A pan-cancer-bioinformatic-based literature review of TRPM7 in cancers

TRPM7, a divalent cation-selective channel with kinase domains, has been widely reported to potentially affect cancers. In this study, we conducted multiple bioinformatic analyses based on open databases and reviewed articles that provided evidence for the effects of TRPM7 on cancers. The purposes of this paper are 1) to provide a pan-cancer overview of TRPM7 in cancers; 2) to summarize evidence of TRPM7 effects on cancers; 3) to identify potential future studies of TRPM7 in cancer. Bioinformatics analysis revealed that no cancer-related TRPM7 mutation was found. TRPM7 is aberrantly expressed in most cancer types but the cancer-noncancer expression pattern varies across cancer types. TRPM7 was not associated with survival, TMB, or cancer stemness in most cancer types. TRPM7 affected drug sensitivity and tumor immunity in some cancer types. The in vitro evidence, preclinical in vivo evidence, and clinical evidence for TRPM7 effects on cancers as well as TRPM7 kinase substrate and TRPM7-targeting drugs associated with cancers were summarized to facilitate comparison. We matched the bioinformatics evidence to literature evidence, thereby unveiling potential avenues for future investigation of TRPM7 in cancers. We believe that this paper will help orient research toward important and relevant aspects of the role of TRPM7 in cancers.

Artemisitene suppresses rheumatoid arthritis progression via modulating METTL3-mediated N6-methyladenosine modification of ICAM2 mRNA in fibroblast-like synoviocytes

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease. We previously revealed that the natural compound artemisitene (ATT) exhibits excellent broad anticancer activities without toxicity on normal tissues. Nevertheless, the effect of ATT on RA is undiscovered. Herein, we aim to study the effect and potential mechanism of ATT on RA management.

METHODS

A collagen-induced arthritis (CIA) mouse model was employed to confirm the anti-RA potential of ATT. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays, cell cycle and apoptosis analysis, immunofluorescence, migration and invasion assays, quantitative real-time PCR (RT-qPCR), Western blot, RNA-sequencing (RNA-seq) analysis, plasmid construction and lentivirus infection, and methylated RNA immunoprecipitation and chromatin immunoprecipitation assays, were carried out to confirm the effect and potential mechanism of ATT on RA management.

RESULTS

ATT relieved CIA in mice. ATT inhibited proliferation and induced apoptosis of RA-fibroblast-like synoviocytes (FLSs). ATT restrained RA-FLSs migration and invasion via suppressing epithelial-mesenchymal transition. RNA-sequencing analysis and bioinformatics analysis identified intercellular adhesion molecule 2 (ICAM2) as a promoter of RA progression in RA-FLSs. ATT inhibits RA progression by suppressing ICAM2/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/p300 pathway in RA-FLSs. Moreover, ATT inhibited methyltransferase-like 3 (METTL3)-mediated N6-methyladenosine methylation of ICAM2 mRNA in RA-FLSs. Interestingly, p300 directly facilitated METTL3 transcription, which could be restrained by ATT in RA-FLSs. Importantly, METTL3, ICAM2 and p300 expressions in synovium tissues of RA patients were related to clinical characteristics and therapy response.

CONCLUSIONS

We provided strong evidence that ATT has therapeutic potential for RA management by suppressing proliferation, migration and invasion, in addition to inducing apoptosis of RA-FLSs through modulating METTL3/ICAM2/PI3K/AKT/p300 feedback loop, supplying the fundamental basis for the clinical application of ATT in RA therapy. Moreover, METTL3, ICAM2 and p300 might serve as biomarkers for the therapy response of RA patients.

ENKUR recruits FBXW7 to ubiquitinate and degrade MYH9 and further suppress MYH9-induced deubiquitination of β-catenin to block gastric cancer metastasis

ENKUR was shown as a suppressor in some tumors. However, the biological role of ENKUR on gastric cancer (GC) and its related molecular mechanisms is not clear. Here, we first observed that ENKUR significantly inhibited cell migration, invasion, and metastasis in GC. The molecular basis showed β-catenin-mediated epithelial-mesenchymal transition (EMT) signaling was inactivated in ENKUR-overexpressing GC cells. In addition, ENKUR knockdown markedly restored cell migration and invasion. Subsequently, ENKUR bound to MYH9 and decreased its protein expression by recruiting E3 ubiquitin ligase FBXW7 to form an ubiquitinated degradation complex. The downregulated MYH9 protein weakened the recruitment of the deubiquitinase USP2 and thus promoted the degradation of β-catenin protein, which finally suppressed EMT signaling. Finally, the oncogenic transcription factor c-Jun bound to ENKUR promoter and reduced its expression in GC. In clinical samples, decreased ENKUR expression promoted the unfavorable prognosis of GC. Our data proved the vital role of ENKUR on suppressing cell migration, invasion, and metastasis and demonstrated its potential as a therapeutic target for GC.

Canonical WNT Signaling Activated by WNT7B Contributes to L-HBs-Mediated Sorafenib Resistance in Hepatocellular Carcinoma by Inhibiting Mitophagy

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death globally, with hepatitis B virus (HBV) infection accounting for over half of all cases. HBV leads to the development of HCC according to a body of literature. Our previous research and other studies also suggest that HBV causes chemotherapeutic treatment resistance, however, the mechanism is uncertain. The WNT family, which encodes secreted signaling molecules, has been linked to carcinogenesis in a variety of malignancies, including HCC. However, little is known regarding WNT7B, a WNT ligand, in the development of HCC and HBV-induced chemoresistance. In this study, the bioinformatics analysis and immunohistochemistry (IHC) staining of clinical samples revealed that WNT7B was overexpressed in HBV-associated HCC tissues versus nontumor liver tissues, which was related to HCC patient survival. Further study in vitro showed that WNT7B and its receptor frizzled-4 (FZD4) were upregulated in response to large hepatitis B surface antigens (L-HBs). L-HBs increased canonical WNT signaling in HCC cells through WNT7B/FZD4. According to functional experiments, WNT7B enhanced the cell proliferation and metastasis in HCC. In vivo and in vitro studies investigated whether L-HBs induced sorafenib resistance by WNT7B in HCC. Interestingly, L-HBs suppressed sorafenib-induced mitophagy by increasing WNT7B/CTNNB1 signaling, resulting in chemoresistance. The findings revealed that WNT7B could be a promising molecular therapeutic target as well as a predictor of sorafenib resistance in HBV-related HCC. The suppression of HBV structural proteins such as L-HBs may play a crucial role in systemic chemotherapy resistance in HBV-associated HCC.

NAP1L5 targeting combined with MYH9 Inhibit HCC progression through PI3K/AKT/mTOR signaling pathway

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide. Nucleosome assembly protein 1-like 5 (NAP1L5) is a protein-coding gene that encodes a protein similar to nucleosome assembly protein 1 (NAP1). It is a histone chaperone that plays an important role in gene transcription in organisms. However, the role of NAP1L5 in the pathogenesis of hepatocellular carcinoma remains to be elucidated. In this study, low expression of NAP1L5 was found in hepatocellular carcinoma, and the downregulation of NAP1L5 was related to shorter survival and disease-free survival. In addition, its expression is also related to the tumor size and recurrence of hepatocellular carcinoma. The overexpression and knockdown of NAP1L5 by plasmid and siRNA showed that NAP1L5 inhibited the proliferation, migration and invasion and induced apoptosis of hepatoma cells. In vivo experiments confirmed that NAP1L5 can inhibit the growth and metastasis of hepatocellular carcinoma cells. In the mechanistic study, we found that NAP1L5 affects the occurrence and development of hepatocellular carcinoma by regulating MYH9 to inhibit the PI3K/AKT/mTOR signaling pathway. As a functional tumor suppressor, NAP1L5 is expressed at low levels in HCC. NAP1L5 inhibits the PI3K/AKT/mTOR signaling pathway in hepatocellular carcinoma by regulating MYH9. It may be a new potential target for liver cancer treatment.

Novel isatin-based hybrids as potential anti-rheumatoid arthritis drug candidates: Synthesis and biological evaluation

Rheumatoid arthritis (RA) is an autoimmune disease accompanied with serious symptoms, such as joint destruction and chronic synovitis. Though many anti-RA drugs could improve the outcome of RA patients to a certain extent, about 40% inefficient rate, severe side effects, and high costs have become urgent problems. Therefore, exploring new alternative drugs for RA therapy is still an urgent need so far. Isatin is an important structural motif found in numerous biologically active compounds and therapeutic agents. Herein, we aim to synthesize several novel isatin analogues for RA therapy and further explore the mechanism of the most potential anti-RA drug candidate in suppressing the pathological progress of RA in vitro and in vivo. We found that the most therapeutic potential compound, a novel small molecule isatin-honokiol hybrid named CT5-2 inhibited the viability of RA-fibroblast-like synoviocytes (FLSs), an effector cell of synovial hyperplasia in the RA synovial tissue with IC50 ranging from 8.54 to 10.66 μM. In addition, CT5-2 reduced the DNA replication and triggered cell cycle arrest and apoptosis of RA-FLSs. Moreover, differential analyses of RNA-sequencing and the mechanistic studies demonstrated that CDCA7 is a key gene correlated with RA progression, and CT5-2 could inhibit the c-Myc/CDCA7/p65 pathway to regulate CDK1, Bcl-2, and vimentin in RA-FLSs. Furthermore, CT5-2 relieved collagen-induced arthritis (CIA) and reduced the level of CDCA7, CDK1, Bcl-2, and vimentin of synovial tissue in CIA mice. Taken together, the novel small molecule isatin-honokiol hybrid CT5-2 exhibits a potential anti-RA drug candidate that inhibits proliferation and triggers cell cycle arrest and apoptosis of RA-FLSs by regulating the c-Myc/CDCA7/p65 pathway. Our study lays a good foundation for further clinical research and structuralmodification of CT5-2.

HBXIP blocks myosin-IIA assembly by phosphorylating and interacting with NMHC-IIA in breast cancer metastasis

Tumor metastasis depends on the dynamic balance of the actomyosin cytoskeleton. As a key component of actomyosin filaments, non-muscle myosin-IIA disassembly contributes to tumor cell spreading and migration. However, its regulatory mechanism in tumor migration and invasion is poorly understood. Here, we found that oncoprotein hepatitis B X-interacting protein (HBXIP) blocked the myosin-IIA assemble state promoting breast cancer cell migration. Mechanistically, mass spectrometry analysis, co-immunoprecipitation assay and GST-pull down assay proved that HBXIP directly interacted with the assembly-competent domain (ACD) of non-muscle heavy chain myosin-IIA (NMHC-IIA). The interaction was enhanced by NMHC-IIA S1916 phosphorylation via HBXIP-recruited protein kinase PKCβII. Moreover, HBXIP induced the transcription of PRKCB, encoding PKCβII, by coactivating Sp1, and triggered PKCβII kinase activity. Interestingly, RNA sequencing and mouse metastasis model indicated that the anti-hyperlipidemic drug bezafibrate (BZF) suppressed breast cancer metastasis via inhibiting PKCβII-mediated NMHC-IIA phosphorylation in vitro and in vivo. We reveal a novel mechanism by which HBXIP promotes myosin-IIA disassembly via interacting and phosphorylating NMHC-IIA, and BZF can serve as an effective anti-metastatic drug in breast cancer.

Oviductal Glycoprotein 1 Promotes Hypertension by Inducing Vascular Remodeling Through an Interaction With MYH9

BACKGROUND

Hypertension is a common cardiovascular disease that is related to genetic and environmental factors, but its mechanisms remain unclear. DNA methylation, a classic epigenetic modification, not only regulates gene expression but is also susceptible to environmental factors, linking environmental factors to genetic modification. Therefore, globally screening differential genomic DNA methylation in patients with hypertension is important for investigating hypertension mechanisms.

METHODS

Differential genomic DNA methylation in patients with hypertension, individuals with prehypertension, and healthy control individuals was screened using Illumina 450K BeadChip and verified by pyrosequencing. Plasma OVGP1 (oviduct glycoprotein 1) levels were determined using an enzyme-linked immunosorbent assay. Ovgp1 transgenic and knockout mice were generated to analyze the function of OVGP1. The blood pressure levels of the mouse models were measured using the tail-cuff system and radiotelemetry methods. The role of OVGP1 in vascular remodeling was determined by vascular relaxation studies. Protein-protein interactions were investigated using a pull-down/mass spectrometry assay and verified with coimmunoprecipitation and pull-down assays.

RESULTS

We found a hypomethylated site at cg20823859 in the promoter region of OVGP1 and plasma OVGP1 levels were significantly increased in patients with hypertension. This finding indicates that OVGP1 is associated with hypertension. In Ovgp1 transgenic mice, OVGP1 overexpression caused an increase in blood pressure, dysfunctional vasoconstriction and vasodilation, remodeling of arterial walls, and increased vascular superoxide stress and inflammation, and these phenomena were exacerbated by angiotensin II infusion. In contrast, OVGP1 deficiency attenuated angiotensin II-induced vascular oxidase stress, inflammation, and collagen deposition. These findings indicate that OVGP1 is a prohypertensive factor that directly promotes vascular remodeling. Pull-down and coimmunoprecipitation assays showed that MYH9 (nonmuscle myosin heavy chain IIA) interacted with OVGP1, whereas inhibition of MYH9 attenuated OVGP1-induced hypertension and vascular remodeling.

CONCLUSIONS

Hypomethylation at cg20823859 in the promoter region of OVGP1 is associated with hypertension and induces upregulation of OVGP1. The interaction between OVGP1 and MYH9 contributes to vascular remodeling and dysfunction. Therefore, OVGP1 is a prohypertensive factor that promotes vascular remodeling by binding with MYH9.

The small molecule chemical compound cinobufotalin attenuates resistance to DDP by inducing ENKUR expression to suppress MYH9-mediated c-Myc deubiquitination in lung adenocarcinoma

The small molecule chemical compound cinobufotalin (CB) is reported to be a potential antitumour drug that increases cisplatin (DDP) sensitivity in nasopharyngeal carcinoma. In this study, we first found that CB decreased DDP resistance, migration and invasion in lung adenocarcinoma (LUAD). Mechanistic studies showed that CB induced ENKUR expression by suppressing PI3K/AKT signalling to downregulate c-Jun, a negative transcription factor of ENKUR. Furthermore, ENKUR was shown to function as a tumour suppressor by binding to β-catenin to decrease c-Jun expression, thus suppressing MYH9 transcription. Interestingly, MYH9 is a binding protein of ENKUR. The Enkurin domain of ENKUR binds to MYH9, and the Myosin_tail of MYH9 binds to ENKUR. Downregulation of MYH9 reduced the recruitment of the deubiquitinase USP7, leading to increased c-Myc ubiquitination and degradation, decreased c-Myc nuclear translocation, and inactivation of epithelial-mesenchymal transition (EMT) signalling, thus attenuating DDP resistance. Our data demonstrated that CB is a promising antitumour drug and may be a candidate chemotherapeutic drug for LUAD patients.

Identification of TLN1 as a prognostic biomarker to effect cell proliferation and differentiation in acute myeloid leukemia

The protein Talin1 encoded by the TLN1 gene is a focal adhesion-related protein that binds to various cytoskeletal proteins and plays an important role in cell adhesion and movement. Recent studies have shown that it is overexpressed in prostate cancer, liver cancer, and oral squamous cell carcinoma, and is closely related to tumor progression and metastasis. This study integrated bioinformatics and functional analysis to reveal the prognosis and potential functions of TLN1 in AML. The results showed that the expression level of TLN1 was abnormally increased in AML and localized in the cell membrane and cytoplasm, and TLN1 is a significant prognostic indicator of overall survival (OS). Enrichment analysis of related genes showed that TLN1 is related to neutrophil mediated immunity, neutrophil activation and may regulate important signal pathways in hematological tumors including tyrosine kinase receptor, FLT3 and PIK3/AKT. The PPI network shows that TLN1 and MYH9 may be involved in the process of AML tumors together with PIP5K1C, ROCK1, S100A4, MY01A and WAC. Immune infiltration analysis explains that TLN1 is associated with multiple immune cells and may be an important immune marker in AML. Furthermore, molecular biology experiments confirmed that TLN1 is related to the proliferation, differentiation and cycle of AML cells. Silencing TLN1 can inhibit the proliferation of AML cells and promote differentiation through the Talin1/P-AKT/CREB signaling pathway.

Targeting prolyl isomerase Pin1 as a promising strategy to overcome resistance to cancer therapies

The development of tumor therapeutic resistance is one of the important reasons for the failure of antitumor therapy. Starting with multiple targets and multiple signaling pathways is helpful in understanding the mechanism of tumor resistance. The overexpression of prolyl isomerase Pin1 is highly correlated with the malignancy of cancer, since Pin1 controls many oncogenes and tumor suppressors, as well as a variety of cancer-driving signaling pathways. Strikingly, numerous studies have shown that Pin1 is directly involved in therapeutic resistance. In this review, we mainly summarize the functions and mechanisms of Pin1 in therapeutic resistance of multifarious cancers, such as breast, liver, and pancreatic carcinomas. Furtherly, from the perspective of Pin1-driven cancer signaling pathways including Raf/MEK/ERK, PI3K/Akt, Wnt/β-catenin, NF-κB, as well as Pin1 inhibitors containing juglone, epigallocatechin-3-gallate (EGCG), all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), it is better to demonstrate the important potential role and mechanism of Pin1 in resistance and sensitization to cancer therapies. It will provide new therapeutic approaches for clinical reversal and prevention of tumor resistance by employing synergistic administration of Pin1 inhibitors and chemotherapeutics, implementing combination therapy of Pin1-related cancer signaling pathway inhibitors and Pin1 inhibitors, and exploiting novel Pin1-specific inhibitors.

Cancer stemness-associated LINC02475 serves as a novel biomarker for diagnosis and prognosis prediction of hepatocellular carcinoma

Purpose: Hepatocellular carcinoma (HCC) is a severe malignant tumor with high incidence and mortality. LncRNAs present broad clinical application prospects. Herein, we aim to identify a cancer stemness associated lncRNA and reveal its role in HCC diagnosis, prognosis evaluation, and progression. Methods: The cancer stemness-associated LINC02475 in HCC samples were identified using bioinformatics analysis. Cellular and molecular experiments were conducted to elucidate the role of LINC02475 in HCC. Results: The firm links between LINC02475 and HCC stemness and prognosis were demonstrated by bioinformatics analysis of public cancer datasets. LINC02475 expression was elevated in HCC, performed well in the diagnosis, and independently predicts poor overall survival (hazard ratio = 1.389, 95% confidence interval = 1.047-1.843, p = 0.023), as well as progression-free survival (hazard ratio = 1.396, 95% confidence interval = 1.016-1.917, p = 0.040) of HCC patients. Moreover, LINC02475 enhanced the tumorigenic pathways necessary for cell stemness, DNA replication required for cell proliferation, epithelial-mesenchymal transition involved in metastasis, and DNA damage repair pathways that drove cell radioresistance and cisplatin resistance, thus promoting HCC progression. Conclusion: Cancer stemness-associated LINC02475 independently predicted a poor prognosis and promoted HCC progression by enhancing stemness, proliferation, metastasis, radioresistance, and chemoresistance. Our study lays a foundation for the clinical application of LINC02475 as a novel biomarker and target for the diagnosis, prognosis evaluation, as well as treatment of HCC.

miR-3682-3p directly targets FOXO3 and stimulates tumor stemness in hepatocellular carcinoma via a positive feedback loop involving FOXO3/PI3K/AKT/c-Myc

BACKGROUND

Cancer stem cells (CSCs) have been implicated in tumorigenesis and tumor recurrence and metastasis are key therapeutic targets in cancer treatment. MicroRNAs display therapeutic potential by controlling the properties of CSCs; however, whether an association exists between miR-3682-3p and CSCs is unknown.

AIM

To investigate the mechanism by which miR-3682-3p promotes stemness maintenance in hepatocellular carcinoma (HCC).

METHODS

MiR-3682-3p expression in HCC cell lines and 34 pairs of normal and HCC specimens was assayed by quantitative polymerase chain reaction. The functional role of miR-3682-3p was investigated in vitro and in vivo. Dual-luciferase reporter and chromatin immunoprecipitation assays were performed for target assessment, and western blotting was utilized to confirm miR-3682-3p/target relationships.

RESULTS

We found that miR-3682-3p plays a key role in HCC pathogenesis by promoting HCC cell stemness. The upregulation of miR-3682-3p enhanced CSC spheroid-forming ability, side population cell fractions, and the expression of CSC factors in HCC cells in vitro and the tumorigenicity of transplanted HCC cells in vivo. Furthermore, silencing miR-3682-3p prolonged the survival of HCC-bearing mice. Mechanistically, we found that miR-3682-3p targets FOXO3 and enables FOXO3/β-catenin interaction, which promotes c-Myc expression through PI3K/AKT; c-Myc, in turn, activates miR-3682-3p, forming a positive feedback loop. Intriguingly, miR-3682-3p expression was induced by hepatitis B virus X protein (HBx) and was involved in HBx-induced tumor stemness-related pathogenesis.

CONCLUSION

Our findings reveal a novel mechanism by which miR-3682-3p promotes stemness in HCC stem cells. Silencing miR-3682-3p may represent a novel therapeutic strategy for HCC.

Mechanisms of resistance to tyrosine kinase inhibitors in liver cancer stem cells and potential therapeutic approaches

The administration of tyrosine kinase inhibitors (TKIs) for the treatment of advanced-stage patients is common in hepatocellular carcinoma (HCC). However, therapy resistance is often encountered, and its emergence eventually curtails long-term clinical benefits. Cancer stem cells (CSCs) are essential drivers of tumor recurrence and therapy resistance; thus, the elucidation of key hallmarks of resistance mechanisms of liver CSC-driven HCC may help improve patient outcomes and reduce relapse. The present review provides a comprehensive summary of the intrinsic and extrinsic mechanisms of TKI resistance in liver CSCs, which mediate treatment failure, and discusses potential strategies to overcome TKI resistance from a preclinical perspective.

RNA helicase DDX24 stabilizes LAMB1 to promote hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Elucidating the underlying mechanisms of this disease could provide new therapeutic strategies for treating HCC. Here, we identified a novel role of DEAD-box helicase 24 (DDX24), a member of the DEAD-box protein family, in promoting HCC progression. DDX24 levels were significantly elevated in HCC tissues and were associated with poor prognosis of HCC. Overexpression of DDX24 promoted HCC migration and proliferation in vitro and in vivo, whereas suppression of DDX24 inhibited both functions. Mechanistically, DDX24 bound the mRNA618-624nt of laminin subunit beta 1 (LAMB1) and increased its stability in a manner dependent upon the interaction between nucleolin (NCL) and the C-terminal region of DDX24. Moreover, RFX8 was identified as a DDX24 promoter-binding protein that transcriptionally upregulated DDX24 expression. Collectively, these findings demonstrate that the RFX8/DDX24/LAMB1 axis promotes HCC progression, providing potential therapeutic targets for HCC.

Identification of STAU1 as a regulator of HBV replication by TurboID-based proximity labeling

The core promoter (CP) of hepatitis B virus (HBV) is critical for HBV replication by controlling the transcription of pregenomic RNA (pgRNA). Host factors regulating the activity of the CP can be identified by different methods. Biotin-based proximity labeling, a powerful method with the capability to capture weak or dynamic interactions, has not yet been used to map proteins interacting with the CP. Here, we established a strategy, based on the newly evolved promiscuous enzyme TurboID, for interrogating host factors regulating the activity of HBV CP. Using this strategy, we identified STAU1 as an important factor involved in the regulation of HBV CP. Mechanistically, STAU1 indirectly binds to CP mediated by TARDBP, and recruits the SAGA transcription coactivator complex to the CP to upregulate its activity. Moreover, STAU1 binds to HBx and enhances the level of HBx by stabilizing it in a ubiquitin-independent manner.

Characteristics of the cancer stem cell niche and therapeutic strategies

Distinct regions harboring cancer stem cells (CSCs) have been identified within the microenvironment of various tumors, and as in the case of their healthy counterparts, these anatomical regions are termed "niche." Thus far, a large volume of studies have shown that CSC niches take part in the maintenance, regulation of renewal, differentiation and plasticity of CSCs. In this review, we summarize and discuss the latest findings regarding CSC niche morphology, physical terrain, main signaling pathways and interactions within them. The cellular and molecular components of CSCs also involve genetic and epigenetic modulations that mediate and support their maintenance, ultimately leading to cancer progression. It suggests that the crosstalk between CSCs and their niche plays an important role regarding therapy resistance and recurrence. In addition, we updated diverse therapeutic strategies in different cancers in basic research and clinical trials in this review. Understanding the complex heterogeneity of CSC niches is a necessary pre-requisite for designing superior therapeutic strategies to target CSC-specific factors and/or components of the CSC niche.

TUBB4A interacts with MYH9 to protect the nucleus during cell migration and promotes prostate cancer via GSK3β/β-catenin signalling

Human tubulin beta class IVa (TUBB4A) is a member of the β-tubulin family. In most normal tissues, expression of TUBB4A is little to none, but it is highly expressed in human prostate cancer. Here we show that high expression levels of TUBB4A are associated with aggressive prostate cancers and poor patient survival, especially for African-American men. Additionally, in prostate cancer cells, TUBB4A knockout (KO) reduces cell growth and migration but induces DNA damage through increased γH2AX and 53BP1. Furthermore, during constricted cell migration, TUBB4A interacts with MYH9 to protect the nucleus, but either TUBB4A KO or MYH9 knockdown leads to severe DNA damage and reduces the NF-κB signaling response. Also, TUBB4A KO retards tumor growth and metastasis. Functional analysis reveals that TUBB4A/GSK3β binds to the N-terminal of MYH9, and that TUBB4A KO reduces MYH9-mediated GSK3β ubiquitination and degradation, leading to decreased activation of β-catenin signaling and its relevant epithelial-mesenchymal transition. Likewise, prostate-specific deletion of Tubb4a reduces spontaneous tumor growth and metastasis via inhibition of NF-κB, cyclin D1, and c-MYC signaling activation. Our results suggest an oncogenic role of TUBB4A and provide a potentially actionable therapeutic target for prostate cancers with TUBB4A overexpression.

The β-tubulin family protein TUBB4A is highly expressed in cancer but it’s molecular role is unclear. Here, the authors show that TUBB4A is required to protect the nucleus from genomic instability during migration and that it’s over expression promotes cancer progression.

N6-methyladenosine modification of CENPK mRNA by ZC3H13 promotes cervical cancer stemness and chemoresistance

BACKGROUND

Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis. In the current study, we determined the relevant players and role of N6-methyladenine (m6A) RNA methylation in cervical cancer progression.

METHODS

The roles of m6A RNA methylation and centromere protein K (CENPK) in cervical cancer were analyzed using bioinformatics analysis. Methylated RNA immunoprecipitation was adopted to detect m6A modification of CENPK mRNA. Human cervical cancer clinical samples, cell lines, and xenografts were used for analyzing gene expression and function. Immunofluorescence staining and the tumorsphere formation, clonogenic, MTT, and EdU assays were performed to determine cell stemness, chemoresistance, migration, invasion, and proliferation in HeLa and SiHa cells, respectively. Western blot analysis, co-immunoprecipitation, chromatin immunoprecipitation, and luciferase reporter, cycloheximide chase, and cell fractionation assays were performed to elucidate the underlying mechanism.

RESULTS

Bioinformatics analysis of public cancer datasets revealed firm links between m6A modification patterns and cervical cancer prognosis, especially through ZC3H13-mediated m6A modification of CENPK mRNA. CENPK expression was elevated in cervical cancer, associated with cancer recurrence, and independently predicts poor patient prognosis [hazard ratio = 1.413, 95% confidence interval = 1.078 - 1.853, P = 0.012]. Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo (P < 0.001). We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK with β-catenin, which promoted β-catenin expression and nuclear translocation, facilitated p53 ubiquitination, and led to activation of Wnt/β-catenin signaling, but suppression of the p53 pathway. This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness, DNA damage repair pathways necessary for cisplatin/carboplatin resistance, epithelial-mesenchymal transition involved in metastasis, and DNA replication that drove tumor cell proliferation.

CONCLUSIONS

CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.

NAP1L1 promotes tumor proliferation through HDGF/C-JUN signaling in ovarian cancer

Background

Nucleosome assembly protein 1-like 1 (NAP1L1) is highly expressed in various types of cancer and plays an important role in carcinogenesis, but its specific role in tumor development and progression remains largely unknown. In this study, we suggest the potential of NAP1L1 as a prognostic biomarker and therapeutic target for the treatment of ovarian cancer (OC).

Methods

In our study, a tissue microarray (TMA) slide containing specimens from 149 patients with OC and 11 normal ovarian tissues underwent immunohistochemistry (IHC) to analyze the correlation between NAP1L1 expression and clinicopathological features. Loss-of- function experiments were performed by transfecting siRNA and following lentiviral gene transduction into SKOV3 and OVCAR3 cells. Cell proliferation and the cell cycle were assessed by the Cell Counting Kit-8, EDU assay, flow cytometry, colony formation assay, and Western blot analysis. In addition, co-immunoprecipitation (Co-IP) and immunofluorescence assays were performed to confirm the relationship between NAP1L1 and its potential targets in SKOV3/OVCAR3 cells.

Results

High expression of NAP1L1 was closely related to poor clinical outcomes in OC patients. After knocking down NAP1L1 by siRNA or shRNA, both SKOV3 and OVCAR3 cells showed inhibition of cell proliferation, blocking of the G1/S phase, and increased apoptosis in vitro. Mechanism analysis indicated that NAP1L1 interacted with hepatoma-derived growth factor (HDGF) and they were co-localized in the cytoplasm. Furthermore, HDGF can interact with jun proto-oncogene (C-JUN), an oncogenic transformation factor that induces the expression of cyclin D1 (CCND1). Overexpressed HDGF in NAP1L1 knockdown OC cells not only increased the expression of C-JUN and CCND1, but it also reversed the suppressive effects of si-NAP1L1 on cell proliferation.

Conclusions

Our data demonstrated that NAP1L1 could act as a prognostic biomarker in OC and can interact with HDGF to mediate the proliferation of OC, and this process of triggered proliferation may contribute to the activation of HDGF/C-JUN signaling in OC cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09356-z.

Dynamics and Functional Interplay of Nonhistone Lysine Crotonylome and Ubiquitylome in Vascular Smooth Muscle Cell Phenotypic Remodeling

Background

The crotonylation of histones is discovered of late as one of the post-translational modifications (PTMs) that can regulate gene expression. However, the function of crotonylation on nonhistone proteins in vascular smooth muscle cells (VSMCs) is unclear. Here, we aim to find the cellular characteristics of crotonylated nonhistone proteins and the cross talk with ubiquitinated proteins in VSMC phenotypic remodeling using the modified omics and proteomic analysis.

Methods

We performed the modified omics and proteomic analysis of VSMCs before and after the stimulation with platelet-derived growth factor-BB (PDGF-BB). The crotonylated and ubiquitinated pan-antibody was used to enrich proteins and then subjected to a high-throughput mass spectrometry analysis. The enrichment analysis was performed within differentially modified proteins in regard to GO terms, KEGG, and protein domains.

Results

As a result, there were 2,138 crotonylation sites in 534 proteins and 1,359 ubiquitination sites corresponding to 657 proteins. These crotonylated proteins detected after PDGF-BB stimulation might be involved in various vital cellular pathways and carry out important functions in VSMCs. Some of them closely took part in significant physiological processes of VSMC phenotypic remodeling, including glycolysis/gluconeogenesis, vascular smooth muscle contraction, and the PI3K-Akt signaling pathway. Furthermore, the KEGG pathway enrichment analysis showed the involvement of ubiquitinated proteins in the physiological processes of VSMC phenotypic remodeling, including glycolysis/gluconeogenesis, vascular smooth muscle contraction, RAS signaling pathway, or the PI3K-Akt signaling pathway. A cross talk analysis showed that there were 199 sites within the 177 proteins modified by crotonylation and ubiquitination simultaneously. Protein–protein interaction (PPI) network analysis indicated that crotonylated and ubiquitinated proteins play an important role in cellular bioprocess commonly and possibly have a synergistic effect.

Conclusion

In summary, our bioinformatics analysis shows that the crotonylation and ubiquitination of nonhistone proteins play an essential role in VSMC phenotypic transformation induced by PDGF-BB stimulation. The cross talk between crotonylation and ubiquitination in glycolysis is possibly a novel mechanism during VSMC phenotypic remodeling.

Glycoprotein PTGDS promotes tumorigenesis of diffuse large B-cell lymphoma by MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling

Glycoprotein prostaglandin D2 synthase (PTGDS) is a member of the lipocalin superfamily and plays dual roles in prostaglandins metabolism and lipid transport. PTGDS has been involved in various cellular processes including the tumorigenesis of solid tumors, yet its role in carcinogenesis is contradictory and the significance of PTGDS in hematological malignancies is ill-defined. Here, we aimed to explore the expression and function of PTGDS in diffuse large B-cell lymphoma (DLBCL), especially the potential role of PTGDS inhibitor, AT56, in lymphoma therapy. Remarkable high expression of PTGDS was found in DLBCL, which was significantly correlated with poor prognosis. PTGDS overexpression and rhPTGDS were found to promote cell proliferation. Besides, in vitro and in vivo studies indicated that PTGDS knockdown and AT56 treatment exerted an anti-tumor effect by regulating cell viability, proliferation, apoptosis, cell cycle, and invasion, and enhanced the drug sensitivity to adriamycin and bendamustine through promoting DNA damage. Moreover, the co-immunoprecipitation-based mass spectrum identified the interaction between PTGDS and MYH9, which was found to promote DLBCL progression. PTGDS inhibition led to reduced expression of MYH9, and then declined activation of the Wnt-β-catenin-STAT3 pathway through influencing the ubiquitination and degradation of GSK3-β in DLBCL. The rescue experiment demonstrated that PTGDS exerted an oncogenic role through regulating MYH9 and then the Wnt-β-catenin-STAT3 pathway. Based on point mutation of glycosylation sites, we confirmed the N-glycosylation of PTGDS in Asn51 and Asn78 and found that abnormal glycosylation of PTGDS resulted in its nuclear translocation, prolonged half-life, and enhanced cell proliferation. Collectively, our findings identified for the first time that glycoprotein PTGDS promoted tumorigenesis of DLBCL through MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling, and highlighted the potential role of AT56 as a novel therapeutic strategy for DLBCL treatment.

Machine Learning Identifies Pan-Cancer Landscape of Nrf2 Oxidative Stress Response Pathway-Related Genes

BACKGROUND

Oxidative stress produced a large amount of reactive oxygen species (ROS), which played a pivotal role in balanced ability and determining cell fate. The activated Nrf2 signaling pathway that responds to the excessive ROS regulated the expressions of antiapoptotic proteins, antioxidative enzymes, drug transporters, and detoxifying factors.

METHODS

The Nrf2 signaling pathway-related genes that had a direct relationship with Nrf2, including ATF4, BACH1, CREBBP, CUL3, EIF2AK3, EP300, FOS, FOSL1, GSK3B, JUN, KEAP1, MAF, MAFF, MAFG, MAFK, MAPK1, MAPK3, MAPK7, MAPK8, MAPK9, PIK3CA, PRRT2, and RIT1, were selected to do a systematic pan-cancer analysis. The relationship of Nrf2 signaling pathway-related gene expressions with tumor mutation burden, microsatellite status, clinical characteristics, immune system, cancer stemness index, and drug sensitivity was calculated by the Spearson correlation analysis across 11,057 subjects representing 33 cancer types. The prognosis models in lung squamous carcinoma, breast cancer, and stomach cancer were constructed with the Cox multivariate regression analysis and least absolute shrinkage and selection operator (Lasso) regression.

RESULTS

Many Nrf2 signaling pathway-related genes were differently expressed between tumor and normal tissues. PIK3CA showed high mutation rate in pan-cancer. The expressions of Nrf2 signaling pathway-related genes were significantly related to tumor mutation burden, copy number variant, microsatellite instability score, survival rate, pathological stage, immune phenotype, immune score, immune cell, cancer stemness index, and drug sensitivity. The prognosis models were significantly associated with survival rate in lung squamous carcinoma, breast cancer, and stomach cancer; and the prognosis model-based riskscore was significantly associated with clinicopathological characteristics of each cancer.

CONCLUSIONS

The study provided a comprehensive pan-cancer landscape of Nrf2 pathway-related genes. Based on the same Nrf2 pathway-related genes, the different prognosis models were constructed for different types of cancers.

Chemically synthesized cinobufagin suppresses nasopharyngeal carcinoma metastasis by inducing ENKUR to stabilize p53 expression

Clinically, the metastasis of tumor cells is the key factor of death in patients with cancer. In this study, we used a model of metastatic nasopharyngeal carcinoma (NPC) to explore the effects of a new chemical, cinobufagin (CB), combined with cisplatin (DDP). We observed that chemically synthesized CB strongly decreased the metastasis of NPC. Furthermore, a better therapeutic effect was shown when CB was combined with DDP. Molecular analysis revealed that CB induced ENKUR expression by deregulating the PI3K/AKT pathway and suppressing c-Jun, an oncogenic transcriptional factor that binds to the ENKUR promoter and negatively modulated its expression in NPC. ENKUR as a tumor suppressor binds to MYH9 and decreases its expression by recruiting β-catenin via its enkurin domain to prevent its nuclear accumulation, which therefore suppresses c-Jun-induced MYH9 expression. Subsequently, downregulated MYH9 reduces the enlistment of E3 ligase UBE3A and thus decreases the UBE3A-mediated ubiquitination degradation of p53, a key tumor suppressor that decreases epithelial-mesenchymal transition (EMT). Clinical sample analysis demonstrated that the ENKUR expression level was significantly reduced in NPC tissues. Its decreased expression substantially promoted clinical progression and reflected poor prognosis for patients with NPC. This study demonstrated that CB induced ENKUR to repress the β-catenin/c-Jun/MYH9 signal and thus decreased UBE3A-mediated p53 ubiquitination degradation. As a result, the EMT signal was inactivated to suppress NPC metastasis.

circ-EIF6 encodes EIF6-224aa to promote TNBC progression via stabilizing MYH9 and activating the Wnt/beta-catenin pathway

The protein-coding ability of circular RNAs (circRNAs) has recently been a hot topic, but the expression and roles of protein-coding circRNAs in triple-negative breast cancer (TNBC) remain uncertain. By intersecting circRNA sequencing data from clinical samples and cell lines, we identified a circRNA, termed circ-EIF6, which predicted a poorer prognosis and correlated with clinicopathological characteristics in a cohort of TNBC patients. Functionally, we showed that circ-EIF6 promoted the proliferation and metastasis of TNBC cells in vitro and in vivo. Mechanistically, we found that circ-EIF6 contains a 675-nucleotide (nt) open reading frame (ORF) and that the -150-bp sequence from ATG functioned as an internal ribosome entry site (IRES), which is required for translation initiation in 5' cap-independent coding RNAs. circ-EIF6 encodes a novel peptide, termed EIF6-224 amino acid (aa), which is responsible for the oncogenic effects of circ-EIF6. The endogenous expression of EIF6-224aa was further examined in TNBC cells and tissues by specific antibody. Moreover, EIF6-224aa directly interacted with MYH9, an oncogene in breast cancer, and decreased MYH9 degradation by inhibiting the ubiquitin-proteasome pathway and subsequently activating the Wnt/beta-catenin pathway. Our study provided novel insights into the roles of protein-coding circRNAs and supported circ-EIF6/EIF6-224aa as a novel promising prognostic and therapeutic target for tailored therapy in TNBC patients.

Protein phosphatase 1 regulatory inhibitor subunit 14C promotes triple-negative breast cancer progression via sustaining inactive glycogen synthase kinase 3 beta

Triple-negative breast cancer (TNBC) is fast-growing and highly metastatic with the poorest prognosis among the breast cancer subtypes. Inactivation of glycogen synthase kinase 3 beta (GSK3β) plays a vital role in the aggressiveness of TNBC; however, the underlying mechanism for sustained GSK3β inhibition remains largely unknown. Here, we find that protein phosphatase 1 regulatory inhibitor subunit 14C (PPP1R14C) is upregulated in TNBC and relevant to poor prognosis in patients. Overexpression of PPP1R14C facilitates cell proliferation and the aggressive phenotype of TNBC cells, whereas the depletion of PPP1R14C elicits opposite effects. Moreover, PPP1R14C is phosphorylated and activated by protein kinase C iota (PRKCI) at Thr73. p-PPP1R14C then represses Ser/Thr protein phosphatase type 1 (PP1) to retain GSK3β phosphorylation at high levels. Furthermore, p-PPP1R14C recruits E3 ligase, TRIM25, toward the ubiquitylation and degradation of non-phosphorylated GSK3β. Importantly, the blockade of PPP1R14C phosphorylation inhibits xenograft tumorigenesis and lung metastasis of TNBC cells. These findings provide a novel mechanism for sustained GSK3β inactivation in TNBC and suggest that PPP1R14C might be a potential therapeutic target.