EGFR signaling promotes nuclear translocation of plasma membrane protein TSPAN8 to enhance tumor progression via STAT3-mediated transcription

Isoliquiritigenin reduces brain metastasis by circNAV3-ST6GALNAC5-EGFR axis in triple negative breast cancer

Brain metastasis (BM) is a serious complication of increasing incidence in patients with advanced breast cancer, which is characterized by swift deterioration in quality of life with few efficient therapy strategies. There is an urgent clinical requirement to devise potent therapeutic strategies for the prevention and management of brain metastases. Here, we report isoliquiritigenin (ISL), a key bioactive substance extracted from licorice root, which effectively inhibited triple negative breast cancer (TNBC) brain metastasis (BM) by downregulation of circNAV3. CircRNAs expression analyses and functional studies, coupled with clinical significance investigations identified circNAV3 as a key molecule promoting TNBC cells BM. Functionally, circNAV3 could promote the proliferation, migration, invasion, angiogenesis and capacity to penetrate the blood-brain barrier of TNBC cells. Mechanismly, circNAV3 could competitively bind with miR-4262, hence intercepting the suppressive effect of miR-4262 on ST6GALNAC5. Subsequently, this interplay enhanced EGFR sialylation and activation, initiating the PI3K/Akt pathway and ultimately fostering the development of TNBC brain metastasis. In conclusion, our research establishes that ISL impede the initiation and advancement of TNBC brain metastasis by modulation of circNAV3/miR-4262/ST6GALNAC5/EGFR axis, laying a theoretical groundwork for the therapeutic use of ISL in this scenario.

Cancer stem cells-derived exosomal TSPAN8 enhances non-stem cancer cells stemness and promotes malignant progression in PDAC

Cancer stem cells (CSC) play a crucial role in pancreatic ductal adenocarcinoma (PDAC) progression and therapeutic resistance. However, the underlying mechanisms and potential targeted treatment strategies remain poorly understood. In this study, we employed single-cell RNA sequencing and exosomal profiling, identifying TSPAN8-enriched exosomes secreted by CSC, which are associated with poor survival rates in PDAC patients. They enhanced stemness in the surrounding non-stem cancer cells (NSCC) by activating the Sonic Hedgehog (Hh) signalling pathway. This exosomal TSPAN8-Hh signalling axis significantly increases the clonogenic ability, invasiveness, and chemoresistance of PDAC cells. Furthermore, TSPAN8-enriched exosomes promoted a higher stem cell frequency, tumourigenicity, and tumour growth rate in vivo, confirming their critical roles in PDAC malignant progression. Our findings underscore the importance of TSPAN8-enriched exosomes for CSC-NSCC communication during PDAC progression.

Exosomal Lipids in Cancer Progression and Metastasis

BACKGROUND

Metastasis is the primary cause of cancer mortality. It is responsible for 90% of all cancer-related deaths. Intercellular communication is a crucial feature underlying cancer metastasis and progression. Cancerous tumors secrete membrane-derived small extracellular vesicles (30-150 nm) into their extracellular milieu. These tiny organelles, known as exosomes, facilitate intercellular communication by transferring bioactive molecules. These exosomes harbor different cargos, such as proteins, nucleic acids, and lipids, that mediate multifaceted functions in various oncogenic processes. Of note, the amount of lipids in exosomes is multifold higher than that of other cargos. Most studies have investigated the role of exosomes' protein and nucleic acid content in various oncogenic processes, while the role of lipid cargo in cancer pathophysiology remains largely obscure.

MATERIALS AND METHODS

We conducted an extensive literature review on the role of exosomes and lipids in cancer progression, specifically addressing the topic of exosomal lipids and their involvement in cancer metastasis and progression.

CONCLUSIONS

This review aims to shed light on the lipid contents of exosomes in cancer metastasis. In this context, the role of exosomal lipids in signaling pathways, immunomodulation, and energy production for cancer cell survival provides insights into overcoming cancer progression and metastasis.

Nerve Growth Factor Signaling Promotes Nuclear Translocation of TRAF4 to Enhance Tumor Stemness and Metastatic Dormancy Via C-Jun-mediated IL-8 Autocrine

Tumor necrosis factor receptor-associated factor 4 (TRAF4), an E3 ubiquitin ligase, is frequently overexpressed in tumors. Although its cytoplasmic role in tumor progression is well-documented, the precise mechanisms underlying its nuclear localization and functional contributions in tumor cells remain elusive. This study demonstrated a positive correlation between the expression of nuclear TRAF4 and both tumor grades and stemness signatures in human cancer tissues. Notably, reduced nuclear TRAF4 led to decreased stemness properties and metastatic dormancy of tumor cells. Conversely, restoring nuclear TRAF4 in TRAF4-knockout (TRAF4-KO) cells augmented these cellular capabilities. Within the nucleus, the TRAF domain of TRAF4 interacted with c-Jun, thereby stimulating its transcriptional activity. This interaction subsequently led to an enhancement of the promoter activity of interleukin-8 (IL-8), which is identified as a mediator of nuclear TRAF4-induced tumor dormancy. Additionally, activation of AKT signaling by nerve growth factor facilitated TRAF4 phosphorylation at Ser242, enhancing its interaction with 14-3-3θ and promoting its nuclear translocation. Importantly, pharmacological modulation of TRAF4 nuclear translocation is found to suppress tumor tumorigenicity and metastasis in tumor models. This study highlights the critical role of nuclear TRAF4 in regulating tumor stemness and dormancy, positioning it as a potential therapeutic target for metastatic and refractory cancers.

RNF31 induces paclitaxel resistance by sustaining ALYREF cytoplasmic-nuclear shuttling in human triple-negative breast cancer

BACKGROUND

Resistance to paclitaxel-based chemotherapy is the major obstacle in triple-negative breast cancer (TNBC) treatment. However, overcoming paclitaxel resistance remains an unsolved problem. The present study aimed to determine whether paclitaxel treatment impairs Aly/REF export factor (ALYREF) cytoplasmic-nuclear shuttling, its mechanism, and the role of ubiquitinated ALYREF in paclitaxel resistance.

METHODS

The subcellular proportion of ALYREF was detected in samples from patients with TNBC using immunohistochemistry to analyze the relationship between ALYREF distribution and paclitaxel response. Cell viability assays, immunofluorescence assays, quantitative real-time reverse transcription PCR assays, western blotting, and terminal deoxynucleotidyl transferase nick-end-labelling assays were conducted to measure the biological function of the subcellular proportion of ALYREF and E3 ligase ring finger protein 31 (RNF31) on paclitaxel sensitivity in TNBC. The synergistic effects of an RNF31 inhibitor plus paclitaxel on TNBC were evaluated. Cox regression models were adopted to assess the prognostic role of RNF31 in TNBC.

RESULTS

Herein, we showed that regulation of ALYREF cytoplasmic-nuclear shuttling is associated with the paclitaxel response in TNBC. In paclitaxel-sensitive TNBC, ALYREF was trapped in the cytoplasm by paclitaxel, while in paclitaxel-resistant TNBC, ALYREF was efficiently transported into the nucleus to exert its function, allowing the export of the mRNAs encoding paclitaxel-resistance-related factors, including tubulin beta 3 class III (TUBB3), stathmin 1 (STMN1), and microtubule-associated protein Tau (TAU), ultimately inducing paclitaxel resistance in TNBC. Mechanistically, we found that RNF31 interacts with and ubiquitinates ALYREF, which facilitates ALYREF nuclear transportation via importin 13 (IPO13) under paclitaxel treatment. Notably, the RNF31 inhibitor and paclitaxel synergistically repressed tumour growth in vivo and in TNBC patient-derived organoids. In addition, analysis of patients with TNBC showed that elevated RNF31 levels correlated with poor prognosis.

CONCLUSION

These data indicated that RNF31-mediated ALYREF ubiquitylation could represent a potent target to reverse paclitaxel resistance in TNBC.

KEY POINTS

RNF31 facilitated ALYREF-mediated PTX resistance in TNBC. RNF31 promoted ALYREF nuclear transport via IPO13 in response to PTX treatment, subsequently enhancing the export of mRNAs encoding PTX resistance-related factors, including TUBB3, STMN1, and TAU. Blocking RNF31 trapped ALYREF in the cytoplasm and induced TNBC cell death upon PTX treatment. Inhibiting RNF31 activity re-sensitized PTX-resistant TNBC to PTX treatment.

Targeting Tetraspanins at Cell Interfaces: Functional Modulation and Exosome-Based Drug Delivery for Precise Disease Treatment

Tetraspanins are key players in various physiological and pathological processes, including malignancy, immune response, fertilization, and infectious disease. Affinity ligands targeting the interactions between tetraspanins and partner proteins are promising for modulating downstream signaling pathways, thus emerging as attractive candidates for interfering related biological functions. Due to the involvement in vesicle biogenesis and cargo trafficking, tetraspanins are also regarded as exosome markers, and become molecular targets for drug loading and delivery. Given the rapid development in these areas, this minireview focuses on recent advances in design and engineering of affinity binders toward tetraspanins including CD63, CD81, and CD9. Their mechanism of actions in modulating protein interactions at cell interfaces and treatment of malignant diseases are discussed. Strategies for constructing exosome-based drug delivery platforms are also reviewed, with emphasis on the important roles of tetraspanins and the affinity ligands. Finally, challenges and future development of tetraspanin-targeting therapy and exosomal drug delivery platforms are also discussed.

Macrophage-specific κ-OR knockout exacerbates inflammation in hypoxic pulmonary hypertension

Hypoxic pulmonary hypertension (HPH), a prevalent subtype of pulmonary arterial hypertension, is characterized by pulmonary vasoconstriction (HPV) and vascular remodeling, accompanied by inflammatory responses. Recent in vivo studies have shown a critical role of the κ-opioid receptor (κ-OR) in modulating the aforementioned pathological processes. Specifically, macrophage-specific κ-OR-knockout models have shown inflammatory response exacerbation with pulmonary hypertension and vascular remodeling. Conversely, the novel κ-OR agonist Q-U50, 488H inhibits inflammatory pathways, thereby attenuating pulmonary vasoconstriction and vascular remodeling. The present study revealed that hypoxia promoted macrophage infiltration and pulmonary artery smooth muscle cell proliferation. Moreover, under these conditions, macrophages secreted interleukin (IL)-6, which triggered the signal transducer and activator of transcription 3 (STAT3)/miR-153-3p signaling cascade. Herein, we identified miR-153-3p downregulated κ-OR gene expression, which is a key contributor to HPV and remodeling, it was identified as a pivotal regulator of κ-OR mRNA levels. The pharmacological activation of κ-OR inhibited IL-6 release from macrophages and disrupted the IL-6/STAT3/miR-153-3p pathway. This dual action of κ-OR activation mitigated pulmonary artery contraction and remodeling, thereby offering a protective mechanism against HPH. The present findings have delineated a novel negative feedback loop driving HPH pathogenesis and suggested that targeting the κ-OR-IL-6-STAT3-miR-153-3p axis represented a promising therapeutic strategy against HPH.

Nuclear transmembrane protein 199 promotes immune escapes by up-regulating programmed death ligand 1

The function of transmembrane protein 199 (TMEM199) in cancer development has rarely been studied thus far. We report the nuclear localization of the TMEM199 protein and further analyzed the truncated fractions that mediate its nuclear localization. Cut&Tag assay globally explores the nuclear-located TMEM199 functions and tests its influence on the immune checkpoint PD-L1 in vitro and in vivo. Nuclear-located TMEM199 regulates PD-L1 mRNA levels by binding to transcription factors such as IFNGR1, IRF1, MTMR9, and Trim28, which all promote PD-L1 mRNA expression. Our study demonstrates the nuclear localization of TMEM199 and its immune regulation functions in cancer development. We uncovered the nuclear localization of TMEM199. TMEM199 is involved in CD274 mRNA gene expression by the transcriptional regulation of the upstream transcription factors or cofactors of CD274, such as IFNGR1, IRF1, MTMR9, KAT8, and Trim28. The nuclear-located TMEM199 is reported to address the tumor immune microenvironment commanding function.

The Biological Roles and Clinical Applications of the PI3K/AKT Pathway in Targeted Therapy Resistance in HER2-Positive Breast Cancer: A Comprehensive Review

Epidermal growth factor receptor 2-positive breast cancer (HER2+ BC) is a highly invasive and malignant type of tumor. Due to its resistance to HER2-targeted therapy, HER2+ BC has a poor prognosis and a tendency for metastasis. Understanding the mechanisms underlying this resistance and developing effective treatments for HER2+ BC are major research challenges. The phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathway, which is frequently altered in cancers, plays a critical role in cellular proliferation and drug resistance. This signaling pathway activates various downstream pathways and exhibits complex interactions with other signaling networks. Given the significance of the PI3K/AKT pathway in HER2+ BC, several targeted drugs are currently in development. Multiple drugs have entered clinical trials or gained market approval, bringing new hope for HER2+ BC therapy. However, new drugs and therapies raise concerns related to safety, regulation, and ethics. Populations of different races and disease statuses exhibit varying responses to treatments. Therefore, in this review, we summarize current knowledge on the alteration and biological roles of the PI3K/AKT pathway, as well as its clinical applications and perspectives, providing new insights for advancing targeted therapies in HER2+ BC.

Nuclear translocation of plasma membrane protein ADCY7 potentiates T cell-mediated antitumour immunity in HCC

BACKGROUND

The potency of T cell-mediated responses is a determinant of immunotherapy effectiveness in treating malignancies; however, the clinical efficacy of T-cell therapies has been limited in hepatocellular carcinoma (HCC) owing to the extensive immunosuppressive microenvironment.

OBJECTIVE

Here, we aimed to investigate the key genes contributing to immune escape in HCC and raise a new therapeutic strategy for remoulding the HCC microenvironment.

DESIGN

The genome-wide in vivo clustered regularly interspaced short palindromic repeats (CRISPR) screen library was conducted to identify the key genes associated with immune tolerance. Single-cell RNA-seq (scRNA-seq), flow cytometry, HCC mouse models, chromatin immunoprecipitation and coimmunoprecipitation were used to explore the function and mechanism of adenylate cyclase 7 (ADCY7) in HCC immune surveillance.

RESULTS

Here, a genome-wide in vivo CRISPR screen identified a novel immune modulator-ADCY7. The transmembrane protein ADCY7 undergoes subcellular translocation via caveolae-mediated endocytosis and then translocates to the nucleus with the help of leucine-rich repeat-containing protein 59 (LRRC59) and karyopherin subunit beta 1 (KPNB1). In the nucleus, it functions as a transcription cofactor of CCAAT/enhancer binding protein alpha (CEBPA) to induce CCL5 transcription, thereby increasing CD8+ T cell infiltration to restrain HCC progression. Furthermore, ADCY7 can be secreted as exosomes and enter neighbouring tumour cells to promote CCL5 induction. Exosomes with high ADCY7 levels promote intratumoural infiltration of CD8+ T cells and suppress HCC tumour growth.

CONCLUSION

We delineate the unconventional function and subcellular location of ADCY7, highlighting its pivotal role in T cell-mediated immunity in HCC and its potential as a promising treatment target.

Unraveling the role of long non-coding RNAs in therapeutic resistance in acute myeloid leukemia: New prospects & challenges

Acute Myeloid Leukemia (AML) is a fatal hematological disease characterized by the unchecked proliferation of immature myeloid blasts in different tissues developed by various mutations in hematopoiesis. Despite intense chemotherapeutic regimens, patients often experience poor outcomes, leading to substandard remission rates. In recent years, long non-coding RNAs (lncRNAs) have increasingly become important prognostic and therapeutic hotspots, due to their contributions to dysregulating many functional epigenetic, transcriptional, and post-translational mechanisms leading to alterations in cell expressions, resulting in increased chemoresistance and reduced apoptosis in leukemic cells. Through this review, I highlight and discuss the latest advances in understanding the major mechanisms through which lncRNAs confer therapy resistance in AML. In addition, I also provide perspective on the current strategies to target lncRNA expressions. A better knowledge of the critical role that lncRNAs play in controlling treatment outcomes in AML will help improve existing medications and devise new ones.

STAT3 drives the expression of HIF1alpha in cancer cells through a novel super-enhancer

Aerobic glycolysis is one of the major hallmarks of malignant tumors. This metabolic reprogramming benefits the rapid proliferation of cancer cells, facilitates the formation of tumor microenvironment to support their growth and survival, and impairs the efficacy of various tumor therapies. Therefore, the elucidation of the mechanisms driving aerobic glycolysis in tumors represents a pivotal breakthrough in developing therapeutic strategies for solid tumors. HIF1α serves as a central regulator of aerobic glycolysis with elevated mRNA and protein expression across multiple tumor types. However, the mechanisms contributing to this upregulation remain elusive. This study reports the identification of a novel HIF1α super enhancer (HSE) in multiple cancer cells using bioinformatics analysis, chromosome conformation capture (3C), chromatin immunoprecipitation (ChIP), and CRISPR/Cas9 genome editing techniques. Deletion of HSE in cancer cells significantly reduces the expression of HIF1α, glycolysis, cell proliferation, colony and tumor formation ability, confirming the role of HSE as the enhancer of HIF1α in cancer cells. Particularly, we demonstrated that STAT3 promotes the expression of HIF1α by binding to HSE. The discovery of HSE will help elucidate the pathways driving tumor aerobic glycolysis, offering new therapeutic targets and potentially resolving the bottleneck in solid tumor treatment.

Perturbation of mammary epithelial cell apicobasal polarity by RHBDF1-facilitated nuclear translocation of PKCζ

BACKGROUND

The establishment of apicobasal polarity in epithelial cells is of critical importance in morphogenesis of mammary gland and other secretive gland tissues. The demise of the polarity is a critical step in early stages of tumorigenesis such as in breast ductal carcinoma in situ. The underlying molecular mechanism thus warrants in-depth investigations.

RESULTS

Protein kinase C isoform ζ (PKCζ), which is highly expressed in breast cancer cells, accumulates in the nuclei of human mammary epithelial cells overexpressing human rhomboid family-1 (RHBDF1), an endoplasmic reticulum membrane protein. Nuclear translocation of PKCζ results in the failure of the formation of the cytosolic apicobasal polarity complex Par, of which PKCζ is an essential component. Additionally, enhanced nuclear translocation of PKCζ is accompanied by an inhibition of the expression of cell tight junction and adherens junction proteins and an increase of cell mobility. Mechanistically, RHBDF1 is able to interact with importin β1 and PKCζ and promote PKCζ phosphorylation. Consistently, treatment of RHBDF1-overexpressing cells with an inhibitor of PKCζ phosphorylation leads to restoration of apicobasal polarity and cell-cell junctions, as well as suppressed cell mobility.

CONCLUSIONS

RHBDF1-facilitated nuclear translocation of PKCζ is critically responsible for the dismantlement of epithelial cell apicobasal polarity, and thus may serve as a target in the development of therapeutic approaches against early stages of breast cancer.

Imperatorin Suppresses Aberrant Hedgehog Pathway and Overcomes Smoothened Antagonist Resistance via STAT3 Inhibition

Background

Hyperactive Hedgehog (Hh) signaling initiates and drives the progression of various tumors. Despite the clinical success of Hh inhibitors targeting Smoothened (SMO), drug resistance, often stemming from SMO mutations, remains a formidable obstacle in cancer therapy. Here, we investigated the potential of imperatorin (IMP), a Chinese herbal medicine, to overcome drug resistance and revealed the potential mechanisms.

Methods

The effect of IMP on Hh signaling pathway was evaluated via Quantitative reverse transcription-polymerase chain reaction, Dual-luciferase reporter assay and Western blot. Meanwhile, we tested its ani-proliferative potential on Hh-driven tumor cells. Loss/gain-of-function, network pharmacology analysis, RNA-sequence analysis and molecular docking were performed to investigate the potential mechanisms of IMP-mediated functions. Furthermore, we established a subcutaneous Hh-driven medulloblastoma xenograft model using the DAOY cell line and examined the in vivo therapeutic efficacy of IMP.

Results

We identified IMP as a novel Hh inhibitor capable of overcoming drug-resistance caused by SMO mutants by inhibiting downstream transcription factor GLI1. IMP suppressed the proliferation of Hh-dependent cancer cells along with Hh activity inhibition. Mechanistically, IMP attenuated the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and its interaction with GLI1 promoter, consequently blocking GLI1 transcription and the target gene expressions. Molecular docking analysis revealed the favorable binding affinity between IMP and STAT3. Importantly, IMP application effectively inhibited the growth of medulloblastoma in vivo, accompanied by the downregulation of GLI1 and phosphorylated STAT3.

Conclusion

Our findings revealed IMP as an innovative approach to combat the drug resistance of SMO inhibitors in Hh-driven tumors, highlighting the crucial role of STAT3 as a transcriptional regulator in Hh signaling.

Verapamil attenuates myocardial ischemia/reperfusion injury by inhibiting apoptosis via activating the JAK2/STAT3 signaling pathway

Apoptosis is a crucial pathological process in myocardial ischemia/reperfusion injury (MIRI). Verapamil (Ver), normally used to treat hypertension or heart rhythm disorders, also attenuates MIRI. The potential of Ver to inhibit apoptosis and thereby attenuate MIRI remains unclear, as does the mechanism. We established an in vivo mouse ischemia/reperfusion (I/R) model by occlusion of the left anterior descending coronary. To construct a hypoxia/reoxygenation model in vitro, H9c2 cardiomyocytes were immersed in a hypoxic buffer in a hypoxia/anaerobic workstation. Ver significantly improved cardiac function and reduced myocardial infarction size in I/R mice, while decreasing apoptosis. Both in vivo and in vitro, application of Ver activated the JAK2/STAT3 signaling pathway and elevated Bcl-2 expression, while decreasing Bax and cleaved caspase-3 levels. Treatment with AG490, a JAK2 inhibitor, partially counteracted the anti-apoptotic and the cardioprotective effect of Ver. Thus, we conclude that Ver alleviates MIRI by reducing apoptosis via the JAK2/STAT3 signaling pathway activation. These findings provide a novel mechanism of Ver in the treatment of MIRI.

The role of S-palmitoylation of C4BPA in regulating murine sperm motility and complement resistance

The epididymis and epididymosomes are crucial for regulating sperm motility, a key factor in male fertility. Palmitoylation, a lipid modification involving the attachment of palmitic acid to cysteine residues, is essential for protein function and localization. Additionally, this modification plays a vital role in the sorting of proteins into exosomes. This study investigates the role of S-palmitoylation at the Cys15 residue of the C4b binding protein alpha chain (C4BPA) in murine sperm motility. Our findings revealed high expression of C4BPA mRNA in the caput epididymis, with the protein present across all regions of the epididymis. Palmitoylation of C4BPA in epididymal epithelial cells was essential for its enrichment in epididymosomes and on sperm, thereby maintaining sperm motility. Inhibition of palmitoylation significantly reduced sperm motility and the localization of C4BPA on sperm. Additionally, palmitoylated C4BPA in exosomes resisted complement C4 attacks, preserving motility, unlike mutated C4BPA (C15S). These results highlight the critical role of palmitoylated C4BPA in protecting sperm from complement attacks and maintaining motility, suggesting that reversible palmitoylation of epididymal proteins could be explored as a therapeutic strategy for male contraception. Our study underscores the importance of post-translational modifications in sperm function and presents new insights into potential male contraceptive methods.

Diagnostic and prognostic significance of tetraspanin 6 and its role in facilitating glioma progression

BACKGROUND

Several tetraspanin (TSPAN) proteins have been implicated in tumorigenesis and disease progression. However, the precise function of tetraspanin 6 (TSPAN6) in glioma remains unclear.

METHODS

Integrated raw data from the Tumor Genome Atlas (TCGA) and Gene Expression Profiling (GEO) databases were processed using R4.2.1. Bioinformatic methods were used to analyze the gene expression levels of TSPAN6 in both glioma and normal brain tissues, correlating them with clinical characteristics. Additionally, the predictive value of TSPAN6 in relation to the immune checkpoint blockade (ICB) therapy response was assessed. In vitro experiments were conducted to investigate the effects of TSPAN6 knockdown on glioma cell proliferation, migration, cell cycle regulation, and macrophage recruitment.

RESULTS

TSPAN6 expression was significantly upregulated in glioma tissues compared to normal tissues. Elevated TSPAN6 expression is strongly correlated with unfavorable clinical characteristics in gliomas. Bioinformatic analyses revealed a significant correlation between elevated TSPAN6 expression and reduced overall survival. Additionally, TSPAN6 was co-expressed with several immune checkpoint genes and revealed a prognostic value in the context of ICB therapy. Functional enrichment analysis revealed the involvement of TSPAN6 in cell-cycle regulation. Furthermore, TSPAN6 expression positively correlated with macrophage and neutrophil infiltration. In vitro experiments confirmed that the downregulation of TSPAN6 inhibited U251 cell proliferation, disrupted the cell cycle, diminished migratory capabilities, and reduced the recruitment of macrophages.

CONCLUSION

Our findings emphasize its potential as both a diagnostic and therapeutic target as well as a predictor of immune therapy response in gliomas.

A MYC-STAMBPL1-TOE1 positive feedback loop mediates EGFR stability in hepatocellular carcinoma

The role of STAM binding protein-like 1 (STAMBPL1), a Lys-63 linkage-specific deubiquitinase, in hepatocellular carcinoma has remained elusive. Here, we report the functions of STAMBPL1 in modulating the stability of the protein and mRNA of the epidermal growth factor receptor (EGFR). STAMBPL1 deficiency attenuates liver tumorigenesis in vitro and in vivo. STAMBPL1 removes K63-linked ubiquitin chains from EGFR to avoid lysosome degradation upon EGF stimulation. STAMBPL1 augments RNA efficient splicing of EGFR to avoid intron retention by activating cleavage of the K63-linked ubiquitin chain on the target of EGR1 protein 1 (TOE1). Moreover, the EGFR-MYC axis has a positive feedback regulation on the transcription of STAMBPL1, and depletion of STAMBPL1 in vivo blunts MYC-driven liver tumorigenesis. Inhibition of STAMBPL1 or TOE1 synergistically improves the antitumor activity of lenvatinib. Our work shows the mechanism of STAMBPL1 in liver cancer and suggests it as a potential therapeutic target for liver cancer treatment.

Nanomedicine in HNSCC therapy-a challenge to conventional therapy

Squamous cell carcinoma of the head and neck (HNSCC) is a difficult-to-treat cancer and treatment is challenging due to recurrence or metastasis. Therefore, there is an urgent need to explore more effective targeted therapies to improve the clinical outcomes and survival of HNSCC patients. The nanomedicine is emerging as a promising strategy to achieve maximal anti-tumor effect in cancer therapy. In this review, we summarize some important signaling pathways and present the current and potential roles of various nanomaterial drug-delivery formulations in HNSCC treatment, aiming to understand the pathogenesis of HNSCC and further improve the therapeutic efficacy of nanomaterial HNSCC. This article seeks to highlight the exciting potential of novel nanomaterials for targeted cancer therapy in HNSCC and thus provide motivation for further research in this field.

IRG1/Itaconate inhibits proliferation and promotes apoptosis of CD69+CD103+CD8+ tissue-resident memory T cells in autoimmune hepatitis by regulating the JAK3/STAT3/P53 signalling pathway

To investigate the protective role of immune response gene 1 (IRG1) and exogenous itaconate in autoimmune hepatitis (AIH) and elucidate the underlying mechanisms. Wild-type and IRG1-/- AIH mouse models were established, and samples of liver tissue and ocular blood were collected from each group of mice to assess the effects of IRG1/itaconate on the expression of pro- and anti-inflammatory cytokines. The levels of liver enzymes and related inflammatory factors were determined using enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction (PCR). Liver histomorphology was detected through hematoxylin and eosin staining and then scored for liver injury, and the infiltration levels of tissue-resident memory T (TRM) cells and related molecules in the liver tissue were detected through immunofluorescence staining in vitro. RNA sequencing and gene enrichment analysis were conducted to identify the corresponding molecules and pathways, and lentiviral transfection was used to generate TRM cell lines with IRG1, Jak3, Stat3, and p53 knockdown. Real-time quantitative PCR and western blot were performed to detect the expression levels of relevant mRNAs and proteins in the liver tissue and cells. The percentage of apoptotic cells was determined using flow cytometry. IRG1/itaconate effectively reduced the release of pro-inflammatory cytokines and the pathological damage to liver tissue, thereby maintaining normal liver function. At the same time, IRG1/itaconate inhibited the JAK3/STAT3 signaling pathway, regulated the expression of related downstream proteins, and inhibited the proliferation and promoted the apoptosis of CD69+CD103+CD8+ TRM cells. For the first time, P53 was found to act as a downstream molecule of the JAK3/STAT3 pathway and was regulated by IRG1/itaconate to promote the apoptosis of CD8+ TRM cells. IRG1/itaconate can alleviate concanavalin A-induced autoimmune hepatitis in mice by inhibiting the proliferation and promoting the apoptosis of CD69+CD103+CD8+ TRM cells via the JAK3/STAT3/P53 pathway.

Role of circular RNAs in preeclampsia (Review)

Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, which affects 3-8% of pregnant individuals worldwide each year. Prevention, diagnosis and treatment of PE are some of the most important problems faced by obstetrics. There is growing evidence that circular RNAs (circRNAs) are involved in the pathogenesis of PE. The present review summarizes the research progress of circRNAs and then describes the expression patterns of circRNAs in PE and their functional mechanisms affecting PE development. The role of circRNAs as biomarkers for the diagnosis of PE, and the research status of circRNAs in PE are summarized in the hope of finding novel strategies for the prevention and treatment of PE.

New insights into the role of tetraspanin 6, 7, and 8 in physiology and pathology

BACKGROUND

The tetraspanin (TSPAN) family comprises 33 membrane receptors involved in various physiological processes in humans. Tetrasapanins are surface proteins expressed in cells of various organisms. They are localised to the cell membrane by four transmembrane domains (TM4SF). These domains bind several cell surface receptors and signalling proteins to tetraspanin-enriched lipid microdomains (TERM or TEM). Tetraspanins play a critical role in anchoring many proteins. They also act as a scaffold for cell signalling proteins.

AIM

To summarise how tetraspanins 6, 7 and 8 contribute to the carcinogenesis process in different types of cancer.

METHODS

To provide a comprehensive review of the role of tetraspanins 6, 7 and 8 in cancer biology, we conducted a thorough search in PubMed, Embase and performed manual search of reference list to collect and extract data.

DISCUSSION

The assembly of tetraspanins covers an area of approximately 100-400 nm. Tetraspanins are involved in various biological processes such as membrane fusion, aggregation, proliferation, adhesion, cell migration and differentiation. They can also regulate integrins, cell surface receptors and signalling molecules. Tetraspanins form direct bonds with proteins and other members of the tetraspanin family, forming a hierarchical network of interactions and are thought to be involved in cell and membrane compartmentalisation. Tetraspanins have been implicated in cancer progression and have been shown to have multiple binding partners and to promote cancer progression and metastasis. Clinical studies have documented a correlation between the level of tetraspanin expression and the prediction of cancer progression, including breast and lung cancer.

CONCLUSIONS

Tetraspanins are understudied in almost all cell types and their functions are not clearly defined. Fortunately, it has been possible to identify the basic mechanisms underlying the biological role of these proteins. Therefore, the purpose of this review is to describe the roles of tetraspanins 6, 7 and 8.

Activation of kappa opioid receptor suppresses post-traumatic osteoarthritis via sequestering STAT3 on the plasma membrane

OBJECTIVE

Kappa opioid receptor (KOR) signaling is involved in joint development and inflammation in Osteoarthritis (OA), while the biochemical mechanism remains unclarified. This study aims to investigate downstream molecular events of KOR activation, to provide novel perspectives in OA pathology.

METHODS

U50,488H, a selective KOR agonist, was intra-articularly injected in mice upon destabilization of the medial meniscus (DMM) as OA models, with PBS injection as control. The behavioral and histological evaluation was assessed by hot plate test and red solid green staining, respectively. Alterations in mRNA and protein expression were assessed by RNA-seq, RT-qPCR, immunohistochemistry and western blotting (WB) in chondrocytes treated with TNF-α or TNF-α + U50,488H. Proteins interacted with KOR were explored using proximity labeling followed by mass spectrometry and then testified by co-immunoprecipitation (Co-IP) assay and immunofluorescence (IF).

RESULTS

OA-induced pain was reduced and cartilage degeneration was alleviated upon KOR activation in DMM mice. In chondrocytes, activation of KOR reversed the upregulation of MMPs, IL-6, IL-1β and phosphorylated(p-) STAT3, stimulated by TNF-α, while the expression of NF-κB, MAPKs and AKT signaling weren't reversed. RNA-seq and IF results presented that KOR activation evidently reduced STAT3 nuclear translocation in chondrocytes upon TNF-α stimuli. The reduction may be resulted from the binding of KOR and STAT3 in the plasma membrane, revealed by proximity labeling and Co-IP results.

CONCLUSIONS

KOR activation protects cartilage from OA, and this protective effect is mainly exerted via sequestering STAT3 on the plasma membrane, resulting in inactivation of STAT3-dependent immune responses which otherwise contributes to OA.

Enhancing cancer therapy: The role of drug delivery systems in STAT3 inhibitor efficacy and safety

The signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, resides in the nucleus to regulate genes essential for vital cellular functions, including survival, proliferation, self-renewal, angiogenesis, and immune response. However, continuous STAT3 activation in tumor cells promotes their initiation, progression, and metastasis, rendering STAT3 pathway inhibitors a promising avenue for cancer therapy. Nonetheless, these inhibitors frequently encounter challenges such as cytotoxicity and suboptimal biocompatibility in clinical trials. A viable strategy to mitigate these issues involves delivering STAT3 inhibitors via drug delivery systems (DDSs). This review delineates the regulatory mechanisms of the STAT3 signaling pathway and its association with cancer. It offers a comprehensive overview of the current application of DDSs for anti-STAT3 inhibitors and investigates the role of DDSs in cancer treatment. The conclusion posits that DDSs for anti-STAT3 inhibitors exhibit enhanced efficacy and reduced adverse effects in tumor therapy compared to anti-STAT3 inhibitors alone. This paper aims to provide an outline of the ongoing research and future prospects of DDSs for STAT3 inhibitors. Additionally, it presents our insights on the merits and future outlook of DDSs in cancer treatment.

TSPAN8+ myofibroblastic cancer-associated fibroblasts promote chemoresistance in patients with breast cancer

Cancer-associated fibroblasts (CAFs) are abundant stromal cells in the tumor microenvironment that promote cancer progression and relapse. However, the heterogeneity and regulatory roles of CAFs underlying chemoresistance remain largely unclear. Here, we performed a single-cell analysis using high-dimensional flow cytometry analysis and identified a distinct senescence-like tetraspanin-8 (TSPAN8)+ myofibroblastic CAF (myCAF) subset, which is correlated with therapeutic resistance and poor survival in multiple cohorts of patients with breast cancer (BC). TSPAN8+ myCAFs potentiate the stemness of the surrounding BC cells through secretion of senescence-associated secretory phenotype (SASP)-related factors IL-6 and IL-8 to counteract chemotherapy. NAD-dependent protein deacetylase sirtuin 6 (SIRT6) reduction was responsible for the senescence-like phenotype and tumor-promoting role of TSPAN8+ myCAFs. Mechanistically, TSPAN8 promoted the phosphorylation of ubiquitin E3 ligase retinoblastoma binding protein 6 (RBBP6) at Ser772 by recruiting MAPK11, thereby inducing SIRT6 protein destruction. In turn, SIRT6 down-regulation up-regulated GLS1 and PYCR1, which caused TSPAN8+ myCAFs to secrete aspartate and proline, and therefore proved a nutritional niche to support BC outgrowth. By demonstrating that TSPAN8+SIRT6low myCAFs were tightly associated with unfavorable disease outcomes, we proposed that the combined regimen of anti-TSPAN8 antibody and SIRT6 activator MDL-800 is a promising approach to overcome chemoresistance. These findings highlight that senescence contributes to CAF heterogeneity and chemoresistance and suggest that targeting TSPAN8+ myCAFs is a promising approach to circumvent chemoresistance.

Targeting C21orf58 is a Novel Treatment Strategy of Hepatocellular Carcinoma by Disrupting the Formation of JAK2/C21orf58/STAT3 Complex

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Functionally uncharacterized genes are an attractive repository to explore candidate oncogenes. It is demonstrated that C21orf58 displays an oncogenic role in promoting cell growth, tumorigenesis and sorafenib resistance of HCC cells by abnormal activation of STAT3 signaling. Mechanistically, a novel manner to regulate STAT3 signaling that adaptor C21orf58 forms a ternary complex is reveal with N-terminal domain of STAT3 and SH2 domain of JAK2, by which C21orf58 overactivates wild-type STAT3 by facilitating its phosphorylation mediated by JAK2, and hyper-activates of constitutively mutated STAT3 due to preferred binding with C21orf58 and JAK2. Moreover, it is validated that inhibition of C21orf58 with drug alminoprofen, selected by virtual screening, could effectively repress the viability and tumorigenesis of HCC cells. Therefore, it is identified that C21orf58 functions as an oncogenic adaptor, reveal a novel regulatory mechanism of JAK2/STAT3 signaling, explain the cause of abnormal activity of activated mutants of STAT3, and explore the attractive therapeutic potential by targeting C21orf58 in HCC.

ANP32B inhibition suppresses the growth of prostate cancer cells by regulating c-Myc signaling

ANP32B is a histone chaperone that interacts with various transcription factors that regulate cancer cell proliferation, immigration, and apoptosis. c-Myc, a well-known oncogenic protein, is a principal player in the initiation and progression of prostate cancer (PC). The means by which ANP32B and c-Myc act remain unknown. We downloaded clinical data from the GEO, TCGA, and other databases to explore ANP32B expression and its effects on the survival of PC and normal tissues. ANP32B-knockdown cell lines were used to evaluate how ANP32B affected cell proliferation in vitro and in vivo. Gene set enrichment analysis and RNAseq were employed to define how ANP32B regulated PC pathways. Immunohistochemical measures were used to detect the expression levels of relevant proteins in xenografts and PC tissues. ANP32B expression increased in PC tissues; ANP32B knockdown inhibited cell growth but this was rescued by c-Myc signaling. ANP32B is thus a PC oncogene and may serve as a valuable therapeutic target when seeking to treat PC.

Molecular characterization, expression pattern and immunologic function of CD82a in large yellow croaker (Larimichthys crocea)

Visceral white spot disease (VWND) caused by Pseudomonas plecoglossicida poses a major threat to the sustainable development of large yellow croaker (Larimichthys crocea) aquaculture. Genome-wide association analysis (GWAS) and RNA-seq research indicated that LcCD82a play an important role in resistance to visceral white spot disease in L. crocea, but the molecular mechanism of LcCD82a response to P. plecoglossicida infection is still unclear. In this study, we cloned and validated the Open Reading Frame (ORF) sequence of LcCD82a and explored the expression profile of LcCD82a in various tissues of L.crocea. In addition, two different transcript variants (LcCD82a-L and LcCD82a-S) of LcCD82a were identified that exhibit alternative splicing patterns after P. plecoglossicida infection, which may be closely related to the immune regulation during pathogenetic process of VWND. In order to explore the function of LcCD82a, we purified the recombinant protein of LcCD82a-L and LcCD82a-S. The bacterial agglutination and apoptosis function analysis showed that LcCD82a may involve in extracellular bacterial recognition, agglutination, and at the same time participate in the process of antigen presentation and induction of cell apoptosis. Collectively, our studies demonstrate that LcCD82a plays a crucial role in regulating apoptosis and antimicrobial immunity.

Molecular Regulation and Oncogenic Functions of TSPAN8

Tetraspanins, a superfamily of small integral membrane proteins, are characterized by four transmembrane domains and conserved protein motifs that are configured into a unique molecular topology and structure in the plasma membrane. They act as key organizers of the plasma membrane, orchestrating the formation of specialized microdomains called "tetraspanin-enriched microdomains (TEMs)" or "tetraspanin nanodomains" that are essential for mediating diverse biological processes. TSPAN8 is one of the earliest identified tetraspanin members. It is known to interact with a wide range of molecular partners in different cellular contexts and regulate diverse molecular and cellular events at the plasma membrane, including cell adhesion, migration, invasion, signal transduction, and exosome biogenesis. The functions of cell-surface TSPAN8 are governed by ER targeting, modifications at the Golgi apparatus and dynamic trafficking. Intriguingly, limited evidence shows that TSPAN8 can translocate to the nucleus to act as a transcriptional regulator. The transcription of TSPAN8 is tightly regulated and restricted to defined cell lineages, where it can serve as a molecular marker of stem/progenitor cells in certain normal tissues as well as tumors. Importantly, the oncogenic roles of TSPAN8 in tumor development and cancer metastasis have gained prominence in recent decades. Here, we comprehensively review the current knowledge on the molecular characteristics and regulatory mechanisms defining TSPAN8 functions, and discuss the potential and significance of TSPAN8 as a biomarker and therapeutic target across various epithelial cancers.

Comprehensive Analysis of MICALL2 Reveals Its Potential Roles in EGFR Stabilization and Ovarian Cancer Cell Invasion

Molecules interacting with CasL (MICALs) are critical mediators of cell motility that act by cytoskeleton rearrangement. However, the molecular mechanisms underlying the regulation of cancer cell invasion remain elusive. The aim of this study was to investigate the potential role of one member of MICALs, i.e., MICALL2, in the invasion and function of ovarian cancer cells. We showed by bioinformatics analysis that MICALL2 expression was significantly higher in tissues of advanced-stage ovarian cancer and associated with poor overall survival of patients. MICALL2 was strongly correlated with the infiltration of multiple types of immune cells and T-cell exhaustion markers. Moreover, enrichment analyses showed that MICALL2 was involved in the tumor-related matrix degradation pathway. Mechanistically, MMP9 was identified as the target gene of MICALL2 for the regulation of invadopodium formation and SKOV3, HO-8910PM cell invasion. In addition, EGFR-AKT-mTOR signaling was identified as the downstream pathway of MICALL2 in the regulation of MMP9 expression. Furthermore, MICALL2 silencing promoted EGFR degradation; however, this effect was abrogated by treatment with the autophagy inhibitors acadesine and chloroquine diphosphate. Silencing of MICALL2 resulted in a suppressive activity of Rac1 while suppressing Rac1 activation attenuated the pro-EGFR, pro-MMP9, and proinvasive effects induced by the overexpression of MICALL2. Collectively, our results indicated that MICALL2 participated in the process of immune infiltration and invasion by ovarian cancer cells. Moreover, MICALL2 prevented EGFR degradation in a Rac1-dependent manner, consequently leading to EGFR-AKT-mTOR-MMP9 signaling activation and invadopodia-mediated matrix degradation.

Inhibition of Cell Apoptosis by Apicomplexan Protozoa-Host Interaction in the Early Stage of Infection

Apicomplexan protozoa, which are a group of specialized intracellular parasitic protozoa, infect humans and other animals and cause a variety of diseases. The lack of research on the interaction mechanism between Apicomplexan protozoa and their hosts is a key factor restricting the development of new drugs and vaccines. In the early stages of infection, cell apoptosis is inhibited by Apicomplexan protozoa through their interaction with the host cells; thereby, the survival and reproduction of Apicomplexan protozoa in host cells is promoted. In this review, the key virulence proteins and pathways are introduced regarding the inhibition of cell apoptosis by the interaction between the protozoa and their host during the early stage of Apicomplexan protozoa infection. It provides a theoretical basis for the development of drugs or vaccines for protozoal diseases.

Tex10 interacts with STAT3 to regulate hepatocellular carcinoma growth and metastasis

Testis expression 10 (Tex10) is reported to be associated with tumorigenesis in several types of cancer types, but its role in hepatocellular carcinoma (HCC) metastasis has not been investigated. In this study, the expression of Tex10 in the HCC cell line and tissue microarray was determined by Western blot and immunohistochemistry (IHC), respectively. RNA sequencing-based transcriptome analysis was performed to identify the Tex10-mediated biological process. Cell Counting Kit-8, colony formation, transwell assays, xenograft tumor growth, and lung metastasis experiments in nude mice were applied to assess the effects of Tex10 on cell proliferation, migration, invasion, and metastasis. The underlying mechanisms were further investigated using dual-luciferase reporter, co-immunoprecipitation, immunofluorescence, and chromatin immunoprecipitation assays. We found that Tex10 was upregulated in HCC tumor tissues compared to adjacent normal tissues, with its expression correlated with a poor prognosis. Gene ontology function enrichment analysis revealed alterations in several biological processes in response to Tex10 knockdown, especially cell motility and cell migration. Functional studies demonstrated that Tex10 promotes HCC cell proliferation, migration, invasion, and metastasis in vitro and in vivo. Moreover, Tex10 was shown to regulate invasion and epithelial-mesenchymal transition via signal transducer and activator of transcription 3 (STAT3) signaling. Mechanistically, Tex10 was found to interact with STAT3 and promote its transcriptional activity. In addition, we found that Tex10 promotes p300-mediated STAT3 acetylation, while p300 silencing abolishes Tex10-enhanced STAT3 transcriptional activity. Together, these findings indicate that Tex10 functions as an oncogene by upregulating STAT3 activity, thus suggesting that Tex10 may serve as a prognostic biomarker and/or therapeutic target for HCC patients.

TSPAN8 regulates EGFR/AKT pathway to enhance metastasis in gastric cancer

BACKGROUND

Tetraspanin 8 (TSPAN8), a transmembrane glycoprotein, is implicated in various pathological conditions including human malignancies. However, the roles and underlying mechanisms of TSPAN8 in promoting gastric cancer(GC) progression are yet to be fully understood.

METHODS AND RESULTS

Our study found that TSPAN8 expression was significantly elevated in GC tissues. We also observed a positive correlation between high TSPAN8 expression and various clinicopathological characteristics of GC, including tumor differentiation, invasion depth, lymph node metastasis, and clinical stage. Moreover, the elevated TSPAN8 expression was indicative of poor prognosis. Functionally, we observed that knockdown of TSPAN8 significantly attenuated while overexpression of TSPAN8 promoted GC cell migration and invasion. In vivo experiments, knockdown of TSPAN8 suppressed lung metastasis in nude mice. We further explored the underlying mechanisms of TSPAN8 and found that it regulated EGFR expression in GC cells by accelerating phosphorylation of EGFR and AKT.

CONCLUSIONS

Our study reveals that TSPAN8 plays a significant role in promoting tumor metastasis by activating the EGFR/AKT pathway, indicating that it may serve as a promising therapeutic target of gastric cancer.

Tetraspanins predict the prognosis and characterize the tumor immune microenvironment of glioblastoma

Glioblastoma (GBM) is the most aggressive and lethal primary brain tumor. Conventional treatments have not achieved breakthroughs in improving survival. Therefore, novel molecular targets and biomarkers need to be identified. As signal transduction docks on the cell membrane, tetraspanins (TSPANs) are associated with various tumors; however, research on their role in GBM remains extremely scarce. Gene expression and clinicopathological characteristic data were obtained from GEPIA, CGGA, HPA, cBioPortal, and GSCA databases to analyze the mRNA and protein expression levels, prognostic value, clinical relevance, mutation status, and targeted drug sensitivity of TSPANs in GBM. Gene set enrichment analysis (GSEA), Gene Ontology (GO), and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used for biological process enrichment. Data from TCGA and TCIA were used to construct the tumor immune microenvironment landscape of TSPANs. Different R software algorithms were used to analyze the immune score, immune cell infiltration, and immune checkpoint correlation. Univariate and multivariate analyses were performed for TSPAN4, which had the most significant predictive prognostic value, and a nomogram model was constructed to predict individual outcomes. The expression and function of TSPAN4 were verified in vitro. TSPAN3/4/6/11/12/18/23/24/25/26/27/28/29/30/31expressions were significantly upregulated in GBM, and TSPAN3/4/6/11/18/24/25/26/29/30 were strongly correlated with prognosis. The expression of multiple TSPANs significantly correlated with 1p/19q co-deletion status, IDH mutation status, recurrence, age, and tumor grade. GSEA and GO analyses revealed the potential contribution of TSPANs in cell adhesion and migration. Immune correlation analysis revealed that TSPANs are related to the formation of the GBM tumor microenvironment (TME) and may influence immunotherapy outcomes. TSPAN4 is an independent prognostic factor and TSPAN4 knockdown has been demonstrated to strongly inhibit glioma cell proliferation, invasion, and migration in vitro. We comprehensively elaborated the prognostic value and potential role of differentially expressed TSPANs in GBM, including molecules that scientists have previously overlooked. This study provides a novel and comprehensive perspective on the pathological mechanisms of GBM and the future direction of individualized tumor immunotherapy, which may be a critical link between GBM malignant progression and TME remodeling.

Membrane-bound transcription factor LRRC4 inhibits glioblastoma cell motility

Membrane-bound transcription factors (MTFs) have been observed in many types of organisms, such as plants, animals and microorganisms. However, the routes of MTF nuclear translocation are not well understood. Here, we reported that LRRC4 is a novel MTF that translocates to the nucleus as a full-length protein via endoplasmic reticulum-Golgi transport, which is different from the previously described nuclear entry mechanism. A ChIP-seq assay showed that LRRC4 target genes were mainly involved in cell motility. We confirmed that LRRC4 bound to the enhancer element of the RAP1GAP gene to activate its transcription and inhibited glioblastoma cell movement by affecting cell contraction and polarization. Furthermore, atomic force microscopy (AFM) confirmed that LRRC4 or RAP1GAP altered cellular biophysical properties, such as the surface morphology, adhesion force and cell stiffness. Thus, we propose that LRRC4 is an MTF with a novel route of nuclear translocation. Our observations demonstrate that LRRC4-null glioblastoma led to disordered RAP1GAP gene expression, which increased cellular movement. Re-expression of LRRC4 enabled it to suppress tumors, and this is a potential for targeted treatment in glioblastoma.

Phloretin-induced STAT3 inhibition suppresses pancreatic cancer growth and progression via enhancing Nrf2 activity

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a malignant pancreatic tumor charactered by a rapid progression and high lethal rate. Hyperactivation of STAT3 signaling exerts a vital effect on the growth and progression of PDAC. While dietary flavonoid phloretin has anti-inflammatory and antioxidant activities, it remains unclear whether phloretin has anti-tumor effects on PDAC.

PURPOSE

The focus of the present study is to elucidate the effects of phloretin on PDAC and investigate its underlying molecular mechanisms.

STUDY DESIGN AND METHODS

Effect of phloretin were assessed in the pancreatic cancer cells (PCCs) by colony formation assay, real-time cell analysis, flow cytometry, Immunofluorescence staining, and cell migration assay. The expressions of mRNA and protein were respectively analyzed by quantitative PCR and Western blotting. A xenograft model was used to appraise the antitumor efficacy of phloretin.

RESULTS

Phloretin treatment significantly restrained cell viability and metastasis, induced DNA injury and ROS accumulation, and triggered mitochondrial-dependent apoptosis in PCCs. Mechanistically, phloretin exhibits anti-tumor potential via inactivating STAT3 signaling and enhancing Nrf2 activity. STAT3 overexpression and Nrf2 silencing partially relieved phloretin-induced inhibition on cell growth and metastasis in PCCs. Phloretin remarkably blocked pancreatic tumor growth and metastasis in vivo.

CONCLUSIONS

Phloretin suppresses pancreatic cancer growth and progression through inhibition of STAT3 mediated by enhancing Nrf2 activity. Phloretin may serve as a promising therapeutic agent for PDAC.

Developing CuS for Predicting Aggressiveness and Prognosis in Lung Adenocarcinoma

Cuproptosis is a newfound cell death form that depends on copper (Cu) ionophores to transport Cu into cancer cells. Studies on the relationship have covered most common cancer types and analyzed the links between cuproptosis-related genes (CRGs) and various aspects of tumor characteristics. In this study, we evaluated the role of cuproptosis in lung adenocarcinoma (LUAD) and constructed the cuproptosis-related score (CuS) to predict aggressiveness and prognosis in LUAD, so as to achieve precise treatment for patients. CuS had a better predictive performance than cuproptosis genes, possibly due to the synergy of SLC family genes, and patients with a high CuS had a poor prognosis. Functional enrichment analysis revealed the correlation between CuS and immune and mitochondrial pathways in multiple datasets. Furthermore, we predicted six potential drugs targeting high-CuS patients, including AZD3759, which is a targeted drug for LUAD. In conclusion, cuproptosis is involved in LUAD aggressiveness, and CuS can accurately predict the prognosis of patients. These findings provide a basis for precise treatment of patients with high CuS in LUAD.

Targeting the EGFR signaling pathway in cancer therapy: What's new in 2023?

INTRODUCTION

Epidermal growth factor receptor (EGFR) is frequently amplified, overexpressed, and mutated in multiple cancers. In normal cell physiology, EGFR signaling controls cellular differentiation, proliferation, growth, and survival. During tumorigenesis, mutations in EGFR lead to increased kinase activity supporting survival, uncontrolled proliferation, and migratory functions of cancer cells. Molecular agents targeting the EGFR pathway have been discovered, and their efficacy has been demonstrated in clinical trials. To date, 14 EGFR-targeted agents have been approved for cancer treatments.

AREAS COVERED

This review describes the newly identified pathways in EGFR signaling, the evolution of novel EGFR-acquired and innate resistance mechanisms, mutations, and adverse side effects of EGFR signaling inhibitors. Subsequently, the latest EGFR/panEGFR inhibitors in preclinical and clinical studies have been summarized. Finally, the consequences of combining immune checkpoint inhibitors and EGFR inhibitors have also been discussed.

EXPERT OPINION

As new mutations are threatened against EGFR-tyrosine kinase inhibitors (TKIs), we suggest the development of new compounds targeting specific mutations without inducing new mutations. We discuss potential future research on developing EGFR-TKIs specific for exact allosteric sites to overcome acquired resistance and reduce adverse events. The rising trend of EGFR inhibitors in the pharma market and their economic impact on real-world clinical practice are discussed.

The versatile roles of testrapanins in cancer from intracellular signaling to cell-cell communication: cell membrane proteins without ligands

The tetraspanins (TSPANs) are a family of four-transmembrane proteins with 33 members in mammals. They are variably expressed on the cell surface, various intracellular organelles and vesicles in nearly all cell types. Different from the majority of cell membrane proteins, TSPANs do not have natural ligands. TSPANs typically organize laterally with other membrane proteins to form tetraspanin-enriched microdomains (TEMs) to influence cell adhesion, migration, invasion, survival and induce downstream signaling. Emerging evidence shows that TSPANs can regulate not only cancer cell growth, metastasis, stemness, drug resistance, but also biogenesis of extracellular vesicles (exosomes and migrasomes), and immunomicroenvironment. This review summarizes recent studies that have shown the versatile function of TSPANs in cancer development and progression, or the molecular mechanism of TSPANs. These findings support the potential of TSPANs as novel therapeutic targets against cancer.

Selenium-ruthenium complex blocks H1N1 influenza virus-induced cell damage by activating GPx1/TrxR1

Background: Influenza A (H1N1) virus is an acute respiratory infectious disease that causes massive morbidity and mortality worldwide. As an essential trace element, selenium is widely applied in the treatment of various diseases because of its functions of enhancing immune response, antioxidant and antiviral mutation. In this study, we constructed the selenium-containing metal complex drug delivery system Ru(biim)(PhenSe)₂ (RuSe), and investigated the anti-influenza virus efficacy and the potential antiviral mechanism for RuSe. Methods: The inhibitory effect of RuSe on influenza-mediated apoptosis was examined by cell count assay, cell cycle assay, Annenxin-V assay, TUNEL-DAPI assay and reactive oxygen species level determination. Virulence assay, PCR and neuraminidase inhibition assay revealed the inhibition of RuSe on influenza virus. At the level of animal experiments, two animal models were used to clarify the role of RuSe through HE staining, immunohistochemical staining, cytokine determination, selenium metabolism determination and selenium protein expression level determination. Results: The results of this study confirm that RuSe enhances the expression levels of selenium proteins GPx1 and TrxR1 by regulating selenium metabolism, thereby inhibiting viral replication and assembly and regulating virus-mediated mitochondria-related apoptosis. On the other hand, animal experiments show that RuSe can reduce lung tissue inflammation and inhibit lung tissue cell apoptosis in mice, and improve the survival state of mice. In addition, RuSe significantly improves the low immune response of Se-deficient mice by regulating selenium metabolism, and effectively alleviated lung fibrosis and lung tissue apoptosis in Se-deficient mice. Conclusions: This study suggests that RuSe provides a promising new approach for the clinical treatment of influenza virus.

High ALDH2 expression is associated with better prognosis in patients with gastric cancer

The relationship among alcohol, acetaldehyde, and gastric cancer (GC) is a very interesting research direction. Although many studies have focused on the correlation between ALDH2 polymorphism and GC, ALDH2 expression in GC and its relationship with the prognosis of GC patients remain to be fully understood. To explore these, 455 GC cases were included in this study. The relationships of ALDH2 expression with patients' survival and clinicopathological characteristics were assessed. The immune infiltration characteristics of ALDH2 in GC were also analyzed. Furthermore, the gene regulatory network and functional pathways of ALDH2 in GC were investigated. We found that high expression of ALDH2 was associated with better prognosis in GC patients. GC patients with high ALDH2 expression had a lower degree of pathological malignancy, consistent with our hypothesis that ALDH2 may play as a tumor suppressor role in GC. Mechanistically, ALDH2 may cooperate with genes such as C5orf32, TSPAN8 and RILP to inhibit GC progression via regulating multiple signaling pathways and chemical carcinogenesis. Therefore, our study suggested that ALDH2, an important variant gene in Asians, might serve as a prognostic marker and a potential therapeutic target for patients with GC.

Photobiomodulation promotes angiogenesis in wound healing through stimulating the nuclear translocation of VEGFR2 and STAT3

In recent years, Photobiomodulation (PBM) has gained prevalence as a kind of physical therapy for wound healing, however, concerning specific cellular mechanisms induced by PBM remains uncertain. The objective of this study is to evaluate the mechanisms of action of PBM (632.8 nm) on angiogenesis in wound healing in vitro and vivo. In the present work, we indicated that PBM with 1.0 J/cm2 irradiation dose exerts positive effects on cell viability, migration, proliferation and tube formation in human umbilical vein endothelial cells (HUVECs). Furthermore, we demonstrate that the VEGFA/VEGFR2/STAT3 pathway plays an important role in PBM effecting cellular function and promoting angiogenesis in wound healing. In addition, we also found that PBM activated the VEGFA/VEGFR2/STAT3 pathway by stimulating VEGFR2 and STAT3 nuclear translocation in the presence of importin-β. Our research offer a new insight into the potential molecular mechanisms in which PBM promotes angiogenesis in wound healing.