HMGB1 Promotes Prostate Cancer Development and Metastasis by Interacting with Brahma-Related Gene 1 and Activating the Akt Signaling Pathway

NAT10 Promotes Prostate Cancer Growth and Metastasis by Acetylating mRNAs of HMGA1 and KRT8

N4-acetylcytidine (ac4C) is essential for the development and migration of tumor cells. According to earlier research, N-acetyltransferase 10 (NAT10) can increase messenger RNAs (mRNAs) stability by catalyzing the synthesis of ac4C. However, little is known about NAT10 expression and its role in the acetylation modifications in prostate cancer (PCa). Thus, the biological function of NAT10 in PCa is investigated in this study. Compared to paraneoplastic tissues, the expression of NAT10 is significantly higher in PCa. The NAT10 expression is strongly correlated with the pathological grade, clinical stage, Gleason score, T-stage, and N-stage of PCa. NAT10 has the ability to advance the cell cycle and the epithelial-mesenchymal transition (EMT), both of which raise the malignancy of tumor cells. Mechanistically, NAT10 enhance the stability of high mobility group AT-hook 1 (HMGA1) by acetylating its mRNA, thereby promoting cell cycle progression to improve cell proliferation. In addition, NAT10 improve the stability of Keratin 8 (KRT8) by acetylating its mRNA, which promotes the progression of EMT to improve cell migration. This findings provide a potential prognostic or therapeutic target for PCa.

Circ_0104652 Promotes the Proliferation and Migration of ox-LDL-Stimulated Vascular Smooth Muscle Cells via Stabilizing ADAMTS7 and HMGB1

BACKGROUND

Atherosclerosis (AS) stands as the primary contributor to cardiovascular disease, a pervasive global health concern. Extensive research has underscored the pivotal role of circular RNAs (circRNAs) in cardiovascular disease development. However, the specific functions of numerous circRNAs in AS remain poorly understood.

METHODS

Quantitative real-time PCR analysis revealed a significant upregulation of circ_0104652 in oxidized low-density lipoprotein (ox-LDL)-induced vascular smooth muscle cells (VSMCs). Loss-of-function experiments were subsequently employed to assess the impact of circ_0104652 on ox-LDL-induced VSMCs.

RESULTS

Silencing circ_0104652 was found to impede the proliferation and migration while promoting the apoptosis of ox-LDL-stimulated VSMCs. Mechanistic assays unveiled that circ_0104652 stabilized ADAM metallopeptidase with thrombospondin type 1 motif 7 (ADAMTS7) and high mobility group box 1 (HMGB1) by recruiting eukaryotic translation initiation factor 4A3 (EIF4A3) protein. Rescue assays further confirmed that circ_0104652 exerted its influence on ox-LDL-induced VSMC proliferation through modulation of ADAMTS7 and HMGB1.

CONCLUSIONS

This study elucidates the role of the circ_0104652/EIF4A3/ADAMTS7/HMGB1 axis in ox-LDL-stimulated VSMCs, providing valuable insights into the intricate mechanisms involved.

Epicardial SMARCA4 deletion exacerbates cardiac injury in myocardial infarction and is related to the inhibition of epicardial epithelial-mesenchymal transition

The reactivated adult epicardium produces epicardium-derived cells (EPDCs) via epithelial-mesenchymal transition (EMT) to benefit the recovery of the heart after myocardial infarction (MI). SMARCA4 is the core catalytic subunit of the chromatin re-modeling complex, which has the potential to target some reactivated epicardial genes in MI. However, the effects of epicardial SMARCA4 on MI remain uncertain. This study found that SMARCA4 was activated over time in epicardial cells following MI, and some of activated cells belonged to downstream differentiation types of EPDCs. This study used tamoxifen to induce lineage tracing and SMARCA4 deletion from epicardial cells in Wt1-CreER;Smarca4fl/fl;Rosa26-RFP adult mice. Epicardial SMARCA4 deletion reduces the number of epicardial cells in adult mice, which was related to changes in the activation, proliferation, and apoptosis of epicardial cells. Epicardial SMARCA4 deletion reduced collagen deposition and angiogenesis in the infarcted area, exacerbated cardiac injury in MI. The exacerbation of cardiac injury was related to the inhibition of generation and differentiation of EPDCs. The alterations in EPDCs were associated with inhibited transition between E-CAD and N-CAD during the epicardial EMT, coupled with the down-regulation of WT1, SNAIL1, and PDGF signaling. In conclusion, this study suggests that Epicardial SMARCA4 plays a critical role in cardiac injury caused by MI, and its regulatory mechanism is related to epicardial EMT. Epicardial SMARCA4 holds potential as a novel molecular target for treating MI.

The Effect of HMGB1 and HMGB2 on Transcriptional Regulation Differs in Neuroendocrine and Adenocarcinoma Models of Prostate Cancer

Human high-mobility group-B (HMGB) proteins regulate gene expression in prostate cancer (PCa), a leading cause of oncological death in men. Their role in aggressive PCa cancers, which do not respond to hormonal treatment, was analyzed. The effects of HMGB1 and HMGB2 silencing upon the expression of genes previously related to PCa were studied in the PCa cell line PC-3 (selected as a small cell neuroendocrine carcinoma, SCNC, PCa model not responding to hormonal treatment). A total of 72% of genes analyzed, using pre-designed primer panels, were affected. HMGB1 behaved mostly as a repressor, but HMGB2 as an activator. Changes in SERPINE1, CDK1, ZWINT, and FN1 expression were validated using qRT-PCR after HMGB1 silencing or overexpression in PC-3 and LNCaP (selected as an adenocarcinoma model of PCa responding to hormonal treatment) cell lines. Similarly, the regulatory role of HMGB2 upon SERPINE1, ZWINT, FN1, IGFPB3, and TYMS expression was validated, finding differences between cell lines. The correlation between the expression of HMGB1, HMGB2, and their targets was analyzed in PCa patient samples and also in PCa subgroups, classified as neuroendocrine positive or negative, in public databases. These results allow a better understanding of the role of HMGB proteins in PCa and contribute to find specific biomarkers for aggressive PCa.

Molecular panorama of therapy resistance in prostate cancer: a pre-clinical and bioinformatics analysis for clinical translation

Prostate cancer (PCa) is a malignant disorder of prostate gland being asymptomatic in early stages and high metastatic potential in advanced stages. The chemotherapy and surgical resection have provided favourable prognosis of PCa patients, but advanced and aggressive forms of PCa including CRPC and AVPC lack response to therapy properly, and therefore, prognosis of patients is deteriorated. At the advanced stages, PCa cells do not respond to chemotherapy and radiotherapy in a satisfactory level, and therefore, therapy resistance is emerged. Molecular profile analysis of PCa cells reveals the apoptosis suppression, pro-survival autophagy induction, and EMT induction as factors in escalating malignant of cancer cells and development of therapy resistance. The dysregulation in molecular profile of PCa including upregulation of STAT3 and PI3K/Akt, downregulation of STAT3, and aberrant expression of non-coding RNAs are determining factor for response of cancer cells to chemotherapy. Because of prevalence of drug resistance in PCa, combination therapy including co-utilization of anti-cancer drugs and nanotherapeutic approaches has been suggested in PCa therapy. As a result of increase in DNA damage repair, PCa cells induce radioresistance and RelB overexpression prevents irradiation-mediated cell death. Similar to chemotherapy, nanomaterials are promising for promoting radiosensitivity through delivery of cargo, improving accumulation in PCa cells, and targeting survival-related pathways. In respect to emergence of immunotherapy as a new tool in PCa suppression, tumour cells are able to increase PD-L1 expression and inactivate NK cells in mediating immune evasion. The bioinformatics analysis for evaluation of drug resistance-related genes has been performed.

The role of pyroptosis and gasdermin family in tumor progression and immune microenvironment

Pyroptosis, an inflammatory programmed cell death, distinguishes itself from apoptosis and necroptosis and has drawn increasing attention. Recent studies have revealed a correlation between the expression levels of many pyroptosis-related genes and both tumorigenesis and progression. Despite advancements in cancer treatments such as surgery, radiotherapy, chemotherapy, and immunotherapy, the persistent hallmark of cancer enables malignant cells to elude cell death and develop resistance to therapy. Recent findings indicate that pyroptosis can overcome apoptosis resistance amplify treatment-induced tumor cell death. Moreover, pyroptosis triggers antitumor immunity by releasing pro-inflammatory cytokines, augmenting macrophage phagocytosis, and activating cytotoxic T cells and natural killer cells. Additionally, it transforms "cold" tumors into "hot" tumors, thereby enhancing the antitumor effects of various treatments. Consequently, pyroptosis is intricately linked to tumor development and holds promise as an effective strategy for boosting therapeutic efficacy. As the principal executive protein of pyroptosis, the gasdermin family plays a pivotal role in influencing pyroptosis-associated outcomes in tumors and can serve as a regulatory target. This review provides a comprehensive summary of the relationship between pyroptosis and gasdermin family members, discusses their roles in tumor progression and the tumor immune microenvironment, and analyses the underlying therapeutic strategies for tumor treatment based on pyroptotic cell death.

Role of HMGB1 and its associated signaling pathways in human malignancies

The High-Mobility Group Box-1 (HMGB1), a non-histone chromatin-associated protein, plays a crucial role in cancer growth and response to therapy as it retains a pivotal role in promoting both cell death and survival. HMGB1 has been reported to regulate several signaling pathways engaged in inflammation, genome stability, immune function, cell proliferation, cell autophagy, metabolism, and apoptosis. However, the association between HMGB1 and cancer is complex and its mechanism in tumorigenesis needs to be further elucidated. This review aims to understand the role of HMGB1 in human malignancies and discuss the signaling pathways linked to this process to provide a comprehensive understanding on the association of HMGB1 with carcinogenesis. Further, we will review the role of HMGB1 as a target/biomarker for cancer therapy, the therapeutic strategies used to target this protein, and its potential role in preventing or treating cancers. In light of the recent growing evidence linking HMGB1 to cancer progression, we think that it may be suggested as a novel and emergent therapeutic target for cancer therapy. Hence, HMGB1 warrants paramount investigation to comprehensively map its role in tumorigenesis.

SETD4 inhibits prostate cancer development by promoting H3K27me3-mediated NUPR1 transcriptional repression and cell cycle arrest

The suppressor of variegation enhancer of zeste-trithorax (SET) domain methyltransferases have been reported to function as key regulators in multiple tumor types by catalyzing histone lysine methylation. Nevertheless, our understanding on the role of these lysine methyltransferases, including SETD4, in prostate cancer (PCa) remains limited. Hence, the specific role of SETD4 in PCa was investigated in this study. The expression of SETD4 in PCa cells and tissue samples was downregulated in PCa cells and tissue specimens, and decreased SETD4 expression led to inferior clinicopathological characteristics in patients with PCa. knockdown of SETD4 facilitated the proliferation of PCa cells and accelerated cell cycle progression. Mechanistically, SETD4 repressed NUPR1 transcription by methylating H3K27 to generate H3K27me3, subsequently inactivated Akt pathway and impeded the tumorigenesis of PCa. Our results highlight that SETD4 prevents the development of PCa by catalyzing the methylation of H3K27 and suppressing NUPR1 transcription, subsequently inactivating the Akt signaling pathway. The findings suggest the potential application of SETD4 in PCa prognosis and therapeutics.

Design, synthesis, and biological evaluation of novel molecules as potent inhibitors of PLK1

Polo-like kinase 1 (PLK1) is an attractive therapeutic target for the treatment of tumors, as it is an essential cell-cycle regulator frequently overexpressed in tumor tissues. PLK1 can promote tumor invasion and metastasis, and is often associated with poor prognosis in cancer patients. However, no PLK1 inhibitor has been granted marketing approval until now. Therefore, more potentially promising PLK1 inhibitors need to be investigated. In this study, a series of novel inhibitors targeting PLK1 was designed and optimized derived from a new scaffold. After synthesis and characterization, we obtained the structure-activity relationship and led to the discovery of the most promising compound 30e for PLK1. The antiproliferative activity against HCT116 cells (IC50 = 5 nM versus 45 nM for onvansertib) and the cellular permeability and efflux ratio were significantly improved (PappA→B = 2.03 versus 0.345 and efflux ratio = 1.65 versus 94.7 for 30e and onvansertib, respectively). Further in vivo studies indicated that 30e had favorable antitumor activity with 116.2% tumor growth inhibition (TGI) in comparison with TGI of 43.0% for onvansertib. Furthermore, 30e improved volume of tumor tissue distribution in mice as compared to onvansertib. This initial study on 30e holds promise for further development of an antitumor agent.

PI3K/Akt signaling in urological cancers: Tumorigenesis function, therapeutic potential, and therapy response regulation

In addition to environmental conditions, lifestyle factors, and chemical exposure, aberrant gene expression and mutations involve in the beginning and development of urological tumors. Even in Western nations, urological malignancies are among the top causes of patient death, and their prevalence appears to be gender dependent. The prognosis for individuals with urological malignancies remains dismal and unfavorable due to the ineffectiveness of conventional treatment methods. PI3K/Akt is a popular biochemical mechanism that is activated in tumor cells as a result of PTEN loss. PI3K/Akt escalates growth and metastasis. Moreover, due to the increase in tumor cell viability caused by PI3K/Akt activation, cancer cells may acquire resistance to treatment. This review article examines the function of PI3K/Akt in major urological tumors including bladder, prostate, and renal tumors. In prostate, bladder, and kidney tumors, the level of PI3K and Akt are notably elevated. In addition, the activation of PI3K/Akt enhances the levels of Bcl-2 and XIAP, hence increasing the tumor cell survival rate. PI3K/Akt ] upregulates EMT pathways and matrix metalloproteinase expression to increase urological cancer metastasis. Furthermore, stimulation of PI3K/Akt results in drug- and radio-resistant cancers, but its suppression by anti-tumor drugs impedes the tumorigenesis.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

A specific RAGE-binding peptide inhibits triple negative breast cancer growth through blocking of Erk1/2/NF-κB pathway

Triple-negative breast cancer (TNBC) is an aggressive cancer that poses a significant threat to women's health. Unfortunately, the lack of clinical targets leads the poor clinical outcomes in TNBC. Many cancers demonstrate overexpression of receptor for advanced glycation end products (RAGE), which can contribute to cancer progression. Despite the potential therapeutic value of blocking RAGE for TNBC treatment, effective peptide drugs have yet to be developed. In our study, we observed that RAGE was highly expressed in TNBC and was associated with poor disease progression. We subsequently investigated the antitumor effects and underlying mechanisms of the RAGE antagonist peptide RP7 in both in vitro and in vivo models of TNBC. Our study revealed that RP7 selectively binds to RAGE-overexpressing TNBC cell lines, including MDA-MB-231 and BT549, and significantly inhibits cell viability, migration, and invasion in both cell lines. Furthermore, RP7-treatment suppressed tumor growth in TNBC xenograft mouse models without inducing detectable toxicity in normal tissues. Mechanistically, RP7 was found to inhibit the phosphorylation of ERK1/2, IKKα/β, IKBα, and p65 to block the NF-κB pathway, prevent the entry of p65 into the nucleus, decrease the protein expression of Bcl-2 and HMGB1, and promote the release of cytochrome C from the mitochondria into the cytoplasm. These effects were observed to activate apoptosis and inhibit epithelial-mesenchymal transition (EMT) in TNBC cells. This study highlights RAGE as a candidate therapeutic target for TNBC treatment and suggests that the RAGE antagonist peptide RP7 is a promising anticancer drug for TNBC.

The Pyroptotic and Nonpyroptotic Roles of Gasdermins in Modulating Cancer Progression and Their Perspectives on Cancer Therapeutics

Gasdermins (GSDMs) are a protein family encoded by six paralogous genes in humans, including GSDMA, GSDMB, GSDMC, GSDMD, GSDME (also known as DFNA5), and DFNB59 (also known as pejvakin). Structurally, members of the GSDM family possess a C-terminus (an autoinhibitory domain) and a positively charged N-terminus (a pore-forming domain) linked with divergent peptide linkers. Recently, GSDMs have been identified as key executors of pyroptosis (an immunogenic programmed cell death) due to their pore-forming activities on the plasma membrane when proteolytically cleaved by caspases or serine proteases. Accumulating studies suggest that chemoresistance is attributed to dysregulation of apoptotic machinery and that inducing pyroptosis to bypass aberrant apoptosis can potently resensitize apoptosis-resistant cancer to chemotherapeutics. Pyroptosis is initiated by pore formation and culminates with plasma membrane rupture; these processes enable the release of proinflammatory cytokines (e.g., IL-1β and IL-18) and damage-associated molecular patterns, which further modulate antitumor immunity within the tumor microenvironment. Although pyroptosis is considered a promising strategy to boost antitumor effects, it is also reported to cause unwanted tissue damage (e.g., gut damage and nephrotoxicity). Intriguingly, mounting evidence has uncovered nonpyroptotic roles of GSDMs in tumorigenesis, such as proliferation, invasion, metastasis, and drug resistance. Thus, this provides a rationale for GSDMs as potential therapeutic targets. Taken together, we shed unbiased light on the pyroptosis-dependent roles of GSDMs in cancer progression and highlighted how GSDMs modulate tumorigenesis in a pyroptosis-independent manner. It is evident that targeting GSDMs seems profound in cancer management; however, several problems require further investigation to target GSDMs from bench to bedside, which is elucidated in the discussion section.

Ferroptosis-mediated immune responses in cancer

Cell death is a universal biological process in almost every physiological and pathological condition, including development, degeneration, inflammation, and cancer. In addition to apoptosis, increasing numbers of cell death types have been discovered in recent years. The biological significance of cell death has long been a subject of interest and exploration and meaningful discoveries continue to be made. Ferroptosis is a newfound form of programmed cell death and has been implicated intensively in various pathological conditions and cancer therapy. A few studies show that ferroptosis has the direct capacity to kill cancer cells and has a potential antitumor effect. As the rising role of immune cells function in the tumor microenvironment (TME), ferroptosis may have additional impact on the immune cells, though this remains unclear. In this study we focus on the ferroptosis molecular network and the ferroptosis-mediated immune response, mainly in the TME, and put forward novel insights and directions for cancer research in the near future.

Brg1 controls stemness and metastasis of pancreatic cancer through regulating hypoxia pathway

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. We previously reported that chromatin remodeler Brg1 is essential for acinar cell-derived PDAC formation in mice. However, the functional role of Brg1 in established PDAC and its metastasis remains unknown. Here, we investigated the importance of Brg1 for established PDAC by using a mouse model with a dual recombinase system. We discovered that Brg1 was a critical player for the cell survival and growth of spontaneously developed PDAC in mice. In addition, Brg1 was essential for metastasis of PDAC cells by inhibiting apoptosis in splenic injection and peritoneal dissemination models. Moreover, cancer stem-like property was compromised in PDAC cells by Brg1 ablation. Mechanistically, the hypoxia pathway was downregulated in Brg1-deleted mouse PDAC and BRG1-low human PDAC. Brg1 was essential for HIF-1α to bind to its target genes to augment the hypoxia pathway, which was important for PDAC cells to maintain their stem-like properties and to metastasize to the liver. Human PDAC cells with high BRG1 expression were more susceptible to BRG1 suppression. In conclusion, Brg1 plays a critical role for cell survival, stem-like property and metastasis of PDAC through the regulation of hypoxia pathway, and thus could be a novel therapeutic target for PDAC.

SOX9 and HMGB3 co-operatively transactivate NANOG and promote prostate cancer progression

BACKGROUND

The homeodomain-containing transcription factor NANOG is overexpressed in prostate adenocarcinoma (PCa) and predicts poor prognosis. The SOX family transcription factor SOX9, as well as the transcription co-activator HMGB3 of the HMGB family, are also overexpressed and may play pivotal roles in PCa. However, it is unknown whether SOX9 and HMGB3 interact with each other, or if they regulate NANOG gene transcription.

METHODS

We identified potential SOX9 responsive elements in NANOG promoter, and investigated if SOX9 regulated NANOG transcription in co-operation with HMGB3 by experimental analysis of potential SOX9 binding sites in NANOG promoter, reporter gene transcription assays with or without interference or artificial overexpression of SOX9 and/or HMGB3, and protein-binding assays of SOX9-HMGB3 interaction. Clinicopathologic and prognostic significance of SOX9-HMGB3 overexpression in PCa was analyzed.

RESULTS

SOX9 activated NANOG gene transcription by preferentially binding to a highly conserved consensus cis-regulatory element (-573 to -568) in NANOG promoter, and promoted the expression of NANOG downstream oncogenic genes. Importantly, HMGB3 functioned as a partner of SOX9 to co-operatively enhance transactivation of NANOG by interacting with SOX9, predominantly via the HMG Box A domain of HMGB3. Overexpression of SOX9 and/or HMGB3 enhanced PCa cell survival and cell migration and were significantly associated with PCa progression. Notably, Cox proportional regression analysis showed that co-overexpression of both SOX9 and HMGB3 was an independent unfavorable prognosticator for both CRPC-free survival (relative risk [RR] = 3.779，95% confidence interval [CI]: 1.159-12.322, p = 0.028) and overall survival (RR = 3.615，95% CI: 1.101-11.876, p = 0.034).

CONCLUSIONS

These findings showed a novel SOX9/HMGB3/NANOG regulatory mechanism, deregulation of which played important roles in PCa progression.

The redox protein HMGB1 in cell death and cancer

SIGNIFICANCE

As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer.

RECENT ADVANCES

HMGB1 is a non-histone nuclear protein that acts as a DNA chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depends on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on tumor types and stages.

CRITICAL ISSUES

A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions.

FUTURE DIRECTIONS

Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease.

CircSMARCC1 facilitates tumor progression by disrupting the crosstalk between prostate cancer cells and tumor-associated macrophages via miR-1322/CCL20/CCR6 signaling

BACKGROUND

Circular RNAs (circRNAs) mediate the infiltration of tumor-associated macrophages (TAMs) to facilitate carcinogenesis and development of various types of cancers. However, the role of circRNAs in regulating macrophages in prostate cancer (PCa) remains uncertain.

METHODS

Differentially expressed circRNAs in PCa were identified by RNA sequencing. The expression of circSMARCC1 was recognized and evaluated using fluorescence in situ hybridization and quantitative real-time PCR. The oncogenic role of circSMARCC1 in PCa tumor proliferation and metastasis was investigated through a series of in vitro and in vivo assays. Finally, Western blot, biotin-labeled RNA pulldown, luciferase assay, rescue experiments, and co-culture experiments with TAMs were conducted to reveal the mechanistic role of circSMARCC1.

RESULTS

CircSMARCC1 was dramatically up-regulated in PCa cells, plasma and tissues. Overexpression of circSMARCC1 promotes tumor proliferation and metastasis both in vitro and in vivo, whereas knockdown of circSMARCC1 exerts the opposite effects. Mechanistically, circSMARCC1 regulates the expression of CC-chemokine ligand 20 (CCL20) via sponging miR-1322 and activate PI3K-Akt signaling pathway involved in the proliferation and epithelial mesenchymal transformation. More importantly, high expression of circSMARCC1 was positively associated with colonization of CD68+/CD163+/CD206+ TAMs in tumor microenvironment. In addition, overexpression of circSMARCC1 facilitates the expression of CD163 in macrophages through the CCL20-CCR6 axis, induces TAMs infiltration and M2 polarization, thereby leading to PCa progression.

CONCLUSIONS

CircSMARCC1 up-regulates the chemokine CCL20 secretion by sponging miR-1322, which is involved in the crosstalk between tumor cells and TAMs by targeting CCL20/CCR6 signaling to promote progression of PCa.

Glycyrrhizic Acid Attenuates Pulmonary Fibrosis of Silicosis by Inhibiting the Interaction between HMGB1 and BRG1 through PI3K/Akt/mTOR Pathway

Purpose: High mobility group protein 1 (HMGB1) is a highly conserved DNA-binding nuclear protein that participates in the occurrence and development of silicosis. HMGB1 binds to its specific receptor and activates phosphatidylinositol 3-kinase (PI3K)/protein kinase B, (PKB; Akt)/mammalian target of rapamycin (mTOR) pathway. Brahma-related genes 1 (BRG1; SMARCA4) is the core subunit of SWI/SNF. HMGB1 activates the Akt pathway through BRG1 to promote the proliferation of prostate cancer. Glycyrrhizic acid is a new pharmacological inhibitor of HMGB1, which may inhibit the occurrence and development of silicosis. We speculate that glycyrrhizic acid inhibits the interaction between HMGB1 and BRG1 through the PI3K/Akt/mTOR pathway to affect the progression of silicosis. Methods: We carried out an in vitro study and stimulated A549 with TGF-β1 to establish an epithelial–mesenchymal transition (EMT) model, knocked down the HMGB1 and BRG1 genes in cells, observed the expression of EMT markers, and detected the interaction between HMGB1 and BRG1 by co-immunoprecipitation. In vivo, we injected glycyrrhizic acid into the mouse silicosis model to inhibit the expression of HMGB1. Results: Both HMGB1 and BRG1 were highly expressed in the process of EMT. After knocking down HMGB1 and BRG1, the process of EMT was inhibited through the PI3K/Akt/mTOR pathway, and their expressions were influenced by each other. HMGB1 and BRG1 interact with each other in A549 cells. HMGB1 and BRG1 are also highly expressed in the mouse silicosis model, and glycyrrhizic acid can inhibit the expression of HMGB1/BRG1 through the PI3K/Akt/mTOR pathway. Conclusion: Glycyrrhizic acid can inhibit the interaction between HMGB1 and BRG1 through the PI3K/Akt/mTOR pathway to affect the progression of silicosis.

The HN1/HMGB1 axis promotes the proliferation and metastasis of hepatocellular carcinoma and attenuates the chemosensitivity to oxaliplatin

Hematological and neurological expressed 1 (HN1) is closely associated with the proliferation and metastasis of various tumors. However, the physiological functions and clinical significance of HN1 in hepatocellular carcinoma (HCC) remain indistinct. In this study, we investigated the role of HN1 in the pathogenesis of HCC and the underlying mechanism using clinical data from HCC patients, in vitro experiments utilizing HCC cell lines and in vivo animal models. We demonstrated that the overexpressed HN1 in HCC was correlated with patients' adverse outcomes. The gain and loss of function experiments indicated that HN1 could promote the proliferation, migration, and invasion of HCC cells in vitro. Furthermore, we found that HN1 knockdown sensitized HCC cells to oxaliplatin. Mechanically, HN1 prevented HMGB1 protein from ubiquitination and degradation via the autophagy-lysosome pathway, which was related to the interaction between HN1 protein and TRIM28 protein. In the nucleus, the downregulation of HMGB1 followed by HN1 knockdown resulted in increased DNA damage and cell death in the oxaliplatin-treated HCC cells. In the cytoplasm, HN1 regulated autophagy via HMGB1. Furthermore, HN1 knockdown in combination with HMGB1 overexpression restored the aggressive phenotypes of HCC cells and the sensitivity of these cells to oxaliplatin. HN1 knockdown inhibited the tumor growth and metastasis, and promoted the anticancer efficiency of oxaliplatin in vivo. In conclusion, our data suggest that the HN1/HMGB1 axis plays an important role in the development/progression and chemotherapy of HCC. Our findings indicate that the HN1/HMGB1 axis may be a promising therapeutic target for HCC treatment.

Up-regulation of LINC00665 contributes to the progression of glioma and correlates with its MRI characteristics

BACKGROUND

LncRNA LINC00665 partakes in controlling the malignant phenotype of cancer cells, but its role in glioma and the related regulatory mechanism remain uncertain.

METHODS

RT-PCR was exploited to examine LINC00665 expression. The relationships among the LINC00665 expression, the clinicopathologic values and magnetic resonance imaging (MRI) characteristics of glioma were analyzed. The multiplication, movement, and aggressiveness of glioma cell lines were evaluated by CCK-8, EdU, and Transwell experiments after constructing LINC00665 overexpression and LINC00665 knockdown cell models. A dual-luciferase reporter gene experiment and RIP experiment were executed to validate the interactions between LINC00665 and miR-129-5p, and between miR-129-5p and HMGB1. Western blot and RT-PCR were conducted to find the impact of LINC00665 and miR-129-5p on HMGB1 expression. Nude mouse model was also constructed to examine the impact of LINC00665 on multiplication and aggressiveness of glioma cells in vivo.

RESULTS

LINC00665 expression was markedly increased in glioma. High LINC00665 expression in glioma was closely linked to larger tumor diameter, higher pathologic grade, heterogeneous MRI signal of the tumor, increased peritumoral edema, and stronger MRI enhancement characteristics. LINC00665 overexpression facilitated the malignant behavior of glioma cells, while LINC00665 knockdown played the reverse role. Mechanistically, LINC00665 could decoy miR-129-5p, and indirectly increased HMGB1 expression.

CONCLUSION

LINC00665 functions as an oncogenic lncRNA in glioma, to accelerate glioma progression by modulating miR-129-5p and increasing HMGB1 expression.

Extracellular Release of HMGB1 as an Early Potential Biomarker for the Therapeutic Response in a Xenograft Model of Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is a non-invasive therapeutic technique for treating malignant tumors, however, methods to evaluate its therapeutic efficacy and adverse reactions are lacking. High mobility group box 1 (HMGB1) is an inflammatory molecule released during cell death. Therefore, we aimed to investigate HMGB1 as a biomarker for BNCT response, by examining the early responses of tumor cells to 10B-boronophenylalanine (BPA)-based BNCT in the Kyoto University Nuclear Reactor. Extracellular HMGB1 release was significantly increased in human squamous carcinoma SAS and melanoma A375 cells 24 h after neutron irradiation but not after γ-irradiation. At 3 days post-BPA-based BNCT irradiation in a SAS xenograft mouse model, plasma HMGB1 levels were higher than those in the non-irradiation control, and HMGB1 was detected in both nuclei and cytoplasm in tumor cells. Additionally, increased plasma HMGB1 levels post-BNCT irradiation were detected even when tumors decreased in size. Collectively, these results indicate that the extracellular HMGB1 release occurs at an early stage and is persistent when tumors are reduced in size; therefore, it is a potential biomarker for evaluating the therapeutic response during BNCT.

HMGB1 Promotes Lymphangiogenesis through the Activation of RAGE on M2 Macrophages in Laryngeal Squamous Cell Carcinoma

Background. Receptor for advanced glycation end products (RAGE) is implicated in tumor biology. Released high mobility group box protein 1 (HMGB1) ligand binding to RAGE receptor in tumor cells promotes tumor progression. The mechanisms of HMGB1-RAGE signaling in M2 macrophages involved in lymphangiogenesis in laryngeal carcinoma remain poorly understood. Here, we assessed the effect of HMGB1-RAGE signaling on M2 macrophages in lymphangiogenesis. Methods. HMGB1, CD163, and D2-40 in laryngeal squamous cell carcinoma (LSCC, $n=123$ ), laryngeal precursor lesions (LPLs, $n=102$ ), and vocal polyp (VP, $n=55$ ) were analyzed by immunohistochemistry. THP-1 cell-expressed RAGE gene was knocked down and then polarized to M0 macrophages and M2 macrophages. IL-23, TNF-α, TGF-β, and IL-10 were measured by ELISA; IL-1β, IL-12, IL-10, and CCL-13 were evaluated by RT-qPCR, and CD206, CD163, and RAGE were evaluated by western blot to evaluate whether classical M2 macrophages were obtained. Conditioned media from RAGE+/- M0 macrophages and RAGE+/- M2 macrophages incubated in the presence or absence of HMGB1, anti-Toll-like receptor (TLR)2, anti-TLR4 antibodies, and anti-VEGF-C antibodies were collected separately for human dermal lymphatic endothelial cells (HDLEC) for proliferation, migration, lymphangiogenesis assay, and VEGF-C concentration analysis. Results. HMGB1 and M2 macrophage densities were increased in LSCC ( $P<0.01$ ). HMGB1 and M2 macrophage densities were significantly correlated with lymphatic vessel density (LVD) in LSCC ( $P<0.01$ ). The HMGB1 overexpression and higher M2 macrophage density were involved in lymph node metastasis ( $P<0.01$ ) and poor prognosis ( $P<0.05$ ). In vitro, conditioned medium from HMGB1-stimulated RAGE+ M2 macrophages activated lymphangiogenesis by upregulating the VEGF compared to controls ( $P<0.05$ ). On the contrary, RAGE knockdown obviously decreased the corresponding effects of HMGB1-preconditioned M2 macrophages upon HDLEC ( $P<0.05$ ). HMGB1-TLR pathway does not significantly increase HDLEC proliferation, migration, and lymphangiogenesis on M2 macrophages. Conclusions. HMGB1 promotes lymphangiogenesis by activation of RAGE on M2 macrophages. Targeting RAGE may provide an effective therapeutic strategy against M2 macrophages in LSCC patients with lymph node metastasis.

Downregulation of LNMAS orchestrates partial EMT and immune escape from macrophage phagocytosis to promote lymph node metastasis of cervical cancer

Epithelial-mesenchymal transition (EMT) is an essential step to drive the metastatic cascade to lymph nodes (LNs) in cervical cancer cells. However, few of them metastasize successfully partially due to increased susceptibility to immunosurveillance conferred by EMT. The precise mechanisms of cancer cells orchestrate EMT and immune evasion remain largely unexplored. In this study, we identified a lncRNA termed lymph node metastasis associated suppressor (LNMAS), which was downregulated in LN-positive cervical cancer patients and correlated with LN metastasis and prognosis. Functionally, LNMAS suppressed cervical cancer cells metastasis in vitro and in vivo. Mechanistically, LNMAS exerts its metastasis suppressive activity by competitively interacting with HMGB1 and abrogating the chromatin accessibility of TWIST1 and STC1, inhibiting TWIST1-mediated partial EMT and STC1-dependent immune escape from macrophage phagocytosis. We further demonstrated that the CpG sites in the promoter region of LNMAS was hypermethylated and contributed to the downregulation of LNMAS. Taken together, our results reveal the essential role of LNMAS in the LN metastasis of cervical cancer and provide mechanistic insights into the regulation of LNMAS in EMT and immune evasion.

Hsa_circ_0003258 promotes prostate cancer metastasis by complexing with IGF2BP3 and sponging miR-653-5p

Background

More and more studies have shown that circular RNAs (circRNAs) play a critical regulatory role in many cancers. However, the potential molecular mechanism of circRNAs in prostate cancer (PCa) remains largely unknown.

Methods

Differentially expressed circRNAs were identified by RNA sequencing. The expression of hsa_circ_0003258 was evaluated using quantitative real-time PCR and RNA in situ hybridization. The impacts of hsa_circ_0003258 on the metastasis of PCa cells were investigated by a series of in vitro and in vivo assays. Lastly, the underlying mechanism of hsa_circ_0003258 was revealed by Western blot, biotin-labeled RNA pulldown, RNA immunoprecipitation, luciferase assays and rescue experiments.

Results

Increased expression of hsa_circ_0003258 was found in PCa tissues and was associated with advanced TNM stage and ISUP grade. Overexpression of hsa_circ_0003258 promoted PCa cell migration by inducing epithelial mesenchymal transformation (EMT) in vitro as well as tumor metastasis in vivo, while knockdown of hsa_circ_0003258 exerts the opposite effect. Mechanistically, hsa_circ_0003258 could elevate the expression of Rho GTPase activating protein 5 (ARHGAP5) via sponging miR-653-5p. In addition, hsa_circ_0003258 physically binds to insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) in the cytoplasm and enhanced HDAC4 mRNA stability, in which it activates ERK signalling pathway, then triggers EMT programming and finally accelerates the metastasis of PCa.

Conclusions

Upregulation of hsa_circ_0003258 drives tumor progression through both hsa_circ_0003258/miR-653-5p/ARHGAP5 axis and hsa_circ_0003258/IGF2BP3 /HDAC4 axis. Hsa_circ_0003258 may act as a promising biomarker for metastasis of PCa and an attractive target for PCa intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-021-01480-x.

The effect of COVID-19 derived cytokine storm on cancer cells progression: double-edged sword

OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-COV2) was first detected in Wuhan, China in December, 2019. The emerging virus causes a respiratory illness, that can trigger a cytokine storm in the body.

METHOD

Cytokine storm in patient's body is associated with severe forms of disease. It is one of the main complications of coronavirus disease-2019 (COVID-19), in which immune cells play a major role. Studies have shown immune cells in the tumor environment can be effective to induce resistance to chemotherapy in cancer patients.

RESULT

Therefore, considering the role of immune cells to induce cytokine storm in COVID-19 patients, and their role to cause resistance to chemotherapy, they are effective on disease progression and creation of severe form of disease.

CONCLUSION

By examining the signaling pathways and inducing resistance to chemotherapy in tumor cells and the cells affect them, it is possible to prevent the occurrence of severe forms of the disease in cancer patients with COVID-19; it is applicable using target therapy and other subsequent treatment strategies.

Autophagic secretion of HMGB1 from cancer-associated fibroblasts promotes metastatic potential of non-small cell lung cancer cells via NFκB signaling

Tumor progression requires the communication between tumor cells and tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are major components of stromal cells. CAFs contribute to metastasis process through direct or indirect interaction with tumor cells; however, the underlying mechanism is largely unknown. Here, we reported that autophagy was upregulated in lung cancer-associated CAFs compared to normal fibroblasts (NFs), and autophagy was responsible for the promoting effect of CAFs on non-small cell lung cancer (NSCLC) cell migration and invasion. Inhibition of CAFs autophagy attenuated their regulation on epithelial–mesenchymal transition (EMT) and metastasis-related genes of NSCLC cells. High mobility group box 1 (HMGB1) secreted by CAFs mediated CAFs’ effect on lung cancer cell invasion, demonstrated by using recombinant HMGB1, HMGB1 neutralizing antibody, and HMGB1 inhibitor glycyrrhizin (GA). Importantly, the autophagy blockade of CAFs revealed that HMGB1 release was dependent on autophagy. We also found HMGB1 was responsible, at least in part, for autophagy activation of CAFs, suggesting CAFs remain active through an autocrine HMGB1 loop. Further study demonstrated that HMGB1 facilitated lung cancer cell invasion by activating the NFκB pathway. In a mouse xenograft model, the autophagy specific inhibitor chloroquine abolished the stimulating effect of CAFs on tumor growth. These results elucidated an oncogenic function for secretory autophagy in lung cancer-associated CAFs that promotes metastasis potential, and suggested HMGB1 as a novel therapeutic target.

Calunduloside E inhibits HepG2 cell proliferation and migration via p38/JNK-HMGB1 signalling axis

High-mobility group box 1 (HMGB1), a highly conserved chromosome protein, is considered as a potential therapeutic target and novel biomarker because of its regulation in the proliferation and metastasis of Hepatocellular carcinoma (HCC). Calenduloside E (CE), a natural active product, has been reported to anti-cancer effect. However, the role and underlying molecular mechanism of CE in HCC is still unclear. The purpose of this study is to investigate the effects of CE on the proliferation and migration of HCC, and then explore the possible underlying molecular mechanism. HepG2 cells were treated with CE or transfected with HMGB1 shRNA plasmids, EdU and colony formation assays were used to detect cell proliferation ability. Wound healing and transwell assays were used to determine the role of CE in cell migration. The expression of Cyclins, PCNA, MMPs, HMGB1, N-cadherin, E-cadherin and phosphorylation of p38, ERK and JNK were all detected using Western blotting. Our results showed that CE inhibited HepG2 cells proliferation and migration in a dose dependent manner; reduced the expression levels of Cycins, PCNA, HMGB1, MMPs and N-cadherin; up-regulated E-cadherin expression; enhanced the phosphorylation of p38 and JNK signalling pathways. Blocking the activation of p38 and JNK obviously reversed CE-mediated inhibitory effects on HepG2 cell proliferation and migration; reversed CE-induced down-regulation of Cyclins, PCNA, MMPs, N-cadherin and HMGB1, as well as E-cadherin up-regulation. In conclusion, our study suggested that CE reduces the expression levels of Cyclins, MMPs and epithelial-mesenchymal transformation (EMT) through p38/JNK-HMGB1 signaling axis and then inhibits HepG2 cells proliferation and migration in HepG2 cells. This study provides a new perspective for the anti-tumour molecular mechanism of CE in HCC.

HMGB1 promotes tumor progression and invasion through HMGB1/TNFR1/NF-κB axis in castration-resistant prostate cancer

Prostate cancer (PCa) is the most common male cancer. Most patients treated with androgen deprivation therapy progress to castration-resistant PCa. To overcome the limitations of this treatment, there is an urgent need to identify more effective treatment targets. High mobility group box 1 protein (HMGB1) is known to be associated with progression, metastasis, and poor prognosis of several solid tumors; however, its role in PCa remains unclear. Thus, we aimed to evaluate the clinical significance and biological roles and mechanism of HMGB1 in PCa. We showed that increased expression of HMGB1 correlated with increased risk of aggressive PCa, and high expression of HMGB1 was associated with poor biochemical recurrence-free survival in a Korean cohort. Additionally, the inhibition of HMGB1 expression significantly reduced cell proliferation, invasive capacity, and NF-κB signaling in vitro. Our results indicated that HMGB1 is a critical factor in the development and progression of PCa. Moreover, we found that HMGB1 directly interacts with TNFR1, and TNFR1 overexpression in HMGB1 knockdown cells reversed the effects of HMGB1 knockdown. Importantly, our results suggest that HMGB1 binding to TNFR1 promotes tumor progression by activating the NF-κB signaling pathway in PCa; therefore, the HMGB1/TNFR1/NF-κB signaling pathway could serve as a novel therapeutic target for improving PCa therapy.

miR-548b Suppresses Melanoma Cell Growth, Migration, and Invasion by Negatively Regulating Its Target Gene HMGB1

Background: Melanoma is one of the most aggressive malignancies. Exploration of metastasis-related genes will improve the clinical outcomes of patients with melanoma. Recently, microRNAs (miRNAs) have been implicated in regulating the aggressiveness of melanoma. In the current study, the author demonstrated the expression of miR-548b and its functions in melanoma. Materials and Methods: The expression levels of miR-548b and high mobility group protein 1 (HMGB1) in melanoma specimens and adjacent normal tissues were examined using the quantitative real-time PCR method. The Cell Counting Kit-8 (CCK-8), wound healing test, and Transwell assays were conducted to examine the impact of miR-548b on aggressive phenotypes of melanoma cells. The protein expression of HMGB1 was detected by Western blot. The tumor growth of melanoma cells in vivo was analyzed using the transplanted tumor model. The expression of HMGB1 in vivo was assessed using immunohistochemistry assay. Results: miR-548b was significantly downregulated in the melanoma sample when compared with adjacent normal tissues. In addition, low levels of miR-548b were related to poor overall survival in patients with melanoma. As predicted, overexpression of miR-548b suppressed the growth and metastasis-associated traits of melanoma cells. Furthermore, the luciferase reporter gene assay and Western blotting revealed that HMGB1 was a target of miR-548b and its expression level was negatively modulated by miR-548b. Several rescue experiments indicated that reintroduction of HMGB1 abolished the inhibiting effects of miR-548b on melanoma cells. Finally, the author demonstrated that upregulation of miR-548b repressed melanoma cell growth in vivo. Conclusions: All these findings demonstrate that miR-548b serves as a cancer-suppressive miRNA in human melanoma by inhibiting HMGB1.

Extracellular HMGB1 blockade inhibits tumor growth through profoundly remodeling immune microenvironment and enhances checkpoint inhibitor-based immunotherapy

Background

High-mobility group box 1 (HMGB1) is a multifunctional redox-sensitive protein involved in various intracellular (eg, chromatin remodeling, transcription, autophagy) and extracellular (inflammation, autoimmunity) processes. Regarding its role in cancer development/progression, paradoxical results exist in the literature and it is still unclear whether HMGB1 mainly acts as an oncogene or a tumor suppressor.

Methods

HMGB1 expression was first assessed in tissue specimens (n=359) of invasive breast, lung and cervical cancer and the two distinct staining patterns detected (nuclear vs cytoplasmic) were correlated to the secretion profile of malignant cells, patient outcomes and the presence of infiltrating immune cells within tumor microenvironment. Using several orthotopic, syngeneic mouse models of basal-like breast (4T1, 67NR and EpRas) or non-small cell lung (TC-1) cancer, the efficacy of several HMGB1 inhibitors alone and in combination with immune checkpoint blockade antibodies (anti-PD-1/PD-L1) was then investigated. Isolated from retrieved tumors, 14 immune cell (sub)populations as well as the activation status of antigen-presenting cells were extensively analyzed in each condition. Finally, the redox state of HMGB1 in tumor-extruded fluids and the influence of different forms (oxidized, reduced or disulfide) on both dendritic cell (DC) and plasmacytoid DC (pDC) activation were determined.

Results

Associated with an unfavorable prognosis in human patients, we clearly demonstrated that targeting extracellular HMGB1 elicits a profound remodeling of tumor immune microenvironment for efficient cancer therapy. Indeed, without affecting the global number of (CD45⁺) immune cells, drastic reductions of monocytic/granulocytic myeloid-derived suppressor cells (MDSC) and regulatory T lymphocytes, a higher M1/M2 ratio of macrophages as well as an increased activation of both DC and pDC were continually observed following HMGB1 inhibition. Moreover, blocking HMGB1 improved the efficacy of anti-PD-1 cancer monoimmunotherapy. We also reported that a significant fraction of HMGB1 encountered within cancer microenvironment (interstitial fluids) is oxidized and, in opposite to its reduced isoform, oxidized HMGB1 acts as a tolerogenic signal in a receptor for advanced glycation endproducts-dependent manner.

Conclusion

Collectively, we present evidence that extracellular HMGB1 blockade may complement first-generation cancer immunotherapies by remobilizing antitumor immune response.

Exosomal HMGB1 Promoted Cancer Malignancy

Simple Summary

In addition to their role in hemostasis and thrombosis, platelets have been implicated in cancer malignancy and thrombocytosis in cancer patients and have been associated with an adverse prognosis. These phenomena indicate that antiplatelet drugs may be useful as an anticancer therapy. Using K562-differentiated megakaryocytes and murine platelets, conditioned medium and exosomes obtained from megakaryocytes and platelets contained high-mobility group box 1 (HMGB1) and promoted cancer cell survival, as well as protected cancer cells from doxorubicin cytotoxicity. Data of tumor-bearing mice established by Lewis lung carcinoma (LLC) cells and C57BL/6 mice revealed that antiplatelet drug dipyridamole and exosome release inhibitor GW4869 mitigated tumor growth and ameliorated concurrent alterations in blood circulation and tumor tissues, as well as platelet infiltration in tumor tissues. Therefore, exosomes and exosomal HMGB1 appear to have roles in platelet-driven cancer malignancy and represent targets of antiplatelet drugs in anticancer treatment.

Abstract

Reciprocal crosstalk between platelets and malignancies underscores the potential of antiplatelet therapy in cancer treatment. In this study, we found that human chronic myeloid leukemia K562 cell-differentiated megakaryocytes and murine platelets produced bioactive substances and these are released into the extracellular space, partly in their exosomal form. High-mobility group box 1 (HMGB1) is a type of exosomal cargo, and the antiplatelet drugs aspirin and dipyridamole interfered with its incorporation into the exosomes. Those released substances and exosomes, along with exogenous HMGB1, promoted cancer cell survival and protected cells from doxorubicin cytotoxicity. In a tumor-bearing model established using murine Lewis lung carcinoma (LLC) cells and C57BL/6 mice, the tumor suppressive effect of dipyridamole correlated well with decreased circulating white blood cells, soluble P-selectin, TGF-β1 (Transforming Growth Factor-β1), exosomes, and exosomal HMGB1, as well as tumor platelet infiltration. Exosome release inhibitor GW4869 exhibited suppressive effects as well. The suppressive effect of dipyridamole on cancer cell survival was paralleled by a reduction of HMGB1/receptor for advanced glycation end-products axis, and proliferation- and migration-related β-catenin, Yes-associated protein 1, Runt-related transcription factor 2, and TGF- β1/Smad signals. Therefore, exosomes and exosomal HMGB1 appear to have roles in platelet-driven cancer malignancy and represent targets of antiplatelet drugs in anticancer treatment.

Targeting the BAF complex in advanced prostate cancer

INTRODUCTION

The BRG1/BRM associated factors (BAF) complex is a chromatin remodeling SWI/SNF which is mutated in 20% of cancers. This complex has many interchangeable subunits which may have oncogenic or tumor suppressor activity in a context-dependent manner. The BAF complex is mutated in 35-50% of metastatic prostate cancer (PC); however, its role in advanced disease is unclear. This review attempts to consolidate current knowledge of the BAF complex in PC and explore potential therapeutic approaches.

AREAS COVERED

This review covers the known roles of some BAF subunits, their alterations, and the models which best explain their mechanisms in driving PC. Following this, the authors provide their expert perspective on how this complex could be targeted in the future with a personalized medicine approach.

EXPERT OPINION

Personalized medicine would allow for patient stratification to exploit synthetic lethal strategies in targeting a mutated BAF complex as shown experimentally in other cancers. BAF dependency can also be targeted in patients stratified for other molecular markers such as BRG1 targeting in phosphatase and tensin homolog (PTEN) deficient PC.

[Dihydromyricetin inhibits proliferation and migration of gastric cancer cells through regulating Akt/STAT3 signaling pathways and HMGB1 expression]

OBJECTIVE

To investigate the inhibitory effects of dihydromyricetin on the proliferation and migration of gastric cancer BGC-823 cells and explore the molecular mechanisms.

METHODS

BGC-823 cells in routine culture were treated with different concentrations of dihydromyricetin (0, 40, 60, 80, 100, and 120 μg/mL) for 24 h, and the changes in cell viability were detected using CCK-8 assay; colony forming assay and Transwell assay were performed to assess the changes in colonyforming and migration abilities of the cells, respectively. The levels of MMP-2 and MMP-9 in the treated cells were determined using ELISA, and Western blotting was used to detect the expressions of E-cadherin, N-cadherin, cyclin D1, cyclin E1, HSP70 and HMGB1 and the phosphorylation levels of Akt and Stat3.

RESULTS

CCK-8 assay showed that dihydromyricetin treatment dose-dependently inhibited the viability of BGC-823 cells (P < 0.05). Treatment with dihydromyricetin obviously suppressed the proliferation and migration of BGC-823 cells, significantly reduced the expression levels of cyclin D1, cyclin E1 and Ncadherin, enhanced E-cadherin expression, inhibited the phosphorylation of Akt and stat3, and downregulated HMGB1 expression in the cells. The results of ELISA demonstrated significantly lowered levels of MMP-2 and MMP-9 in dihydromyricetin-treated cells.

CONCLUSIONS

Dihydromyricetin inhibits the proliferation and migration of BGC-823 cells through suppressing the activation of Akt/stat3 signaling pathways and HMGB1 expression.

Circular RNA 0081146 facilitates the progression of gastric cancer by sponging miR-144 and up-regulating HMGB1

OBJECTIVES

Recent studies have revealed that circular RNA (circRNA) plays a pivotal role in cancer development. The study aimed to investigate the role of circ_0081146 in gastric cancer (GC).

RESULTS

Circ_0081146 was upregulated in GC tissues and cells. Patients with high expression of circ_0081146 had a significantly reduced 5-year overall survival rate. Circ_0081146 knockdown restrained the growth, migration and invasion of GC cells in vitro as well as tumorigenesis in vivo. Circ_0081146 targeted miR-144 and HMGB1 was targeted by miR-144. Circ_0081146 was negatively correlated with miR-144 expression, while positively correlated with HMGB1 expression in GC tissues. Moreover, the inhibitory effect of circ_0081146 knockdown on the progression of GC cells were reversed by silencing miR-144 or HMGB1 overexpression. Mechanically, circ_0081146 increased HMGB1 expression by targeting miR-144.

CONCLUSION

Circ_0081146 functions as an oncogene in GC to promote cell growth, migration and invasion via modulating the miR-144/HMGB1 axis.

Chromatin-directed proteomics-identified network of endogenous androgen receptor in prostate cancer cells

Treatment of prostate cancer confronts resistance to androgen receptor (AR)-targeted therapies. AR-associated coregulators and chromatin proteins hold a great potential for novel therapy targets. Here, we employed a powerful chromatin-directed proteomics approach termed ChIP-SICAP to uncover the composition of chromatin protein network, the chromatome, around endogenous AR in castration resistant prostate cancer (CRPC) cells. In addition to several expected AR coregulators, the chromatome contained many nuclear proteins not previously associated with the AR. In the context of androgen signaling in CRPC cells, we further investigated the role of a known AR-associated protein, a chromatin remodeler SMARCA4 and that of SIM2, a transcription factor without a previous association with AR. To understand their role in chromatin accessibility and AR target gene expression, we integrated data from ChIP-seq, RNA-seq, ATAC-seq and functional experiments. Despite the wide co-occurrence of SMARCA4 and AR on chromatin, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, especially those involved in cell morphogenetic changes in epithelial-mesenchymal transition. The depletion also inhibited the CRPC cell growth, validating SMARCA4's functional role in CRPC cells. Although silencing of SIM2 reduced chromatin accessibility similarly, it affected the expression of a much larger group of androgen-regulated genes, including those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of CRPC cells and tumor size in chick embryo chorioallantoic membrane assay, further emphasizing the importance of SIM2 in CRPC cells and pointing to the functional relevance of this potential prostate cancer biomarker in CRPC cells. Overall, the chromatome of AR identified in this work is an important resource for the field focusing on this important drug target.

Emerging Autophagy Functions Shape the Tumor Microenvironment and Play a Role in Cancer Progression - Implications for Cancer Therapy

The tumor microenvironment (TME) is a complex environment where cancer cells reside and interact with different types of cells, secreted factors, and the extracellular matrix. Additionally, TME is shaped by several processes, such as autophagy. Autophagy has emerged as a conserved intracellular degradation pathway for clearance of damaged organelles or aberrant proteins. With its central role, autophagy maintains the cellular homeostasis and orchestrates stress responses, playing opposite roles in tumorigenesis. During tumor development, autophagy also mediates autophagy-independent functions associated with several hallmarks of cancer, and therefore exerting several effects on tumor suppression and/or tumor promotion mechanisms. Beyond the concept of degradation, new different forms of autophagy have been described as modulators of cancer progression, such as secretory autophagy enabling intercellular communication in the TME by cargo release. In this context, the synthesis of senescence-associated secretory proteins by autophagy lead to a senescent phenotype. Besides disturbing tumor treatment responses, autophagy also participates in innate and adaptive immune signaling. Furthermore, recent studies have indicated intricate crosstalk between autophagy and the epithelial-mesenchymal transition (EMT), by which cancer cells obtain an invasive phenotype and metastatic potential. Thus, autophagy in the cancer context is far broader and complex than just a cell energy sensing mechanism. In this scenario, we will discuss the key roles of autophagy in the TME and surrounding cells, contributing to cancer development and progression/EMT. Finally, the potential intervention in autophagy processes as a strategy for cancer therapy will be addressed.

Eldecalcitol induces apoptosis and autophagy in human osteosarcoma MG-63 cells by accumulating ROS to suppress the PI3K/Akt/mTOR signaling pathway

Eldecalcitol (ED-71) is a new type of vitamin D analog, and vitamin D has been reported to have therapeutic effects in infectious disease, autoimmune disease, and cancer. However, the anti-cancer effect of ED-71 remains unclear. The objective of this study was to explore the anti-cancer effect of ED-71 in human osteosarcoma cells and to identify the related mechanism. The CCK8 assay results showed that ED-71 inhibited MG-63 cell viability in dose and time dependent manners. Cloning and Transwell invasion assays showed that ED-71 inhibited clonal and invasion ability of MG-63 cells. Flow cytometry results showed ED-71 the G2/M cycle arrest rate, apoptosis, and intracellular ROS. Western blot was used to detect cleaved-caspase-3, Bax, Bcl-2, LC3-II/LC3-I, and P62 levels and the mTOR pathway. The increase of LC3-II and P62 indicated that ED-71 induced the formation of autophagosomes and inhibited autophagy flux. Furthermore, ED-71-induced apoptosis was weakened after adding 3-methyladenine and ED-71-induced early autophagy was weakened by caspase-3 inhibitor (Z-VAD-FMK), which indicated the two processes active each other in the presence of ED-71. Furthermore, N-acetylcysteine (NAC) pretreatment reversed the ED-71-treatment outcomes, including increased apoptosis and autophagy and inhibition of the PI3K/Akt/mTOR pathway. In conclusion, our results reveal that ED-71 induced G2/M arrest, apoptosis and autophagy in MG-63 cells by accumulating ROS to suppress the PI3K/Akt/mTOR signaling pathway.

The Impact of HMGB1 Polymorphisms on Prostate Cancer Progression and Clinicopathological Characteristics

Prostate cancer is one of the major cancers of the genitourinary tract. High-mobility group box 1 (HMGB1) was suggested as a promising therapeutic target for prostate cancer. In this study, we aim to elucidate the associations of HMGB1 single nucleotide polymorphisms (SNPs) with prostate cancer susceptibility and clinicopathological characteristics. The HMGB1 SNPs rs1412125, rs2249825, rs1045411, and rs1360485 in 579 prostate cancer patients and 579 cancer-free controls were analyzed with real-time polymerase chain reactions (real-time PCR). All of the data were evaluated with SAS statistical software. Our results showed that the HMGB1 rs1045411 T allele genotype was significantly associated with advanced pathologic T stage (odds ratio (OR) = 1.433, 95% confidence interval (CI) = 1.021–2.012; p = 0.037) and pathologic N1 stage (OR = 2.091, 95% CI = 1.160–3.767; p = 0.012), and the rs1360485 polymorphic CT + TT genotype was associated with pathologic Gleason grade group (4 + 5) (OR = 1.583, 95% CI = 1.017–2.462; p = 0.041), pathologic T stage (3 + 4) (OR = 1.482, 95% CI = 1.061–2.070; p = 0.021), and pathologic N1 stage (OR = 2.131, 95% CI = 1.178–3.852; p = 0.011) compared with their wild-type carriers. In conclusion, our results revealed that the HMGB1 SNPs were associated with the clinical status of prostate cancer. The HMGB1 SNPs may have the potential to predict prostate cancer disease progression.

Circular RNA circLPAR3 Facilitates Esophageal Squamous Cell Carcinoma Progression Through Upregulating HMGB1 via Sponging miR-375/miR-433

Background

Circular RNAs (circRNAs) are critical regulators of many diseases, including esophageal squamous cell carcinoma (ESCC). A recent study has shown that circLPAR3 is highly expressed in ESCC, but its role and mechanism in ESCC are still unclear.

Methods

The expression levels of circLPAR3, microRNA-375 (miR-375), miR-433, and high-mobility group box 1 (HMGB1) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The circular characteristic and localization of circLPAR3 were identified by Ribonuclease R (RNase R) and nuclear-cytoplasmic separation assay. Also, cell proliferation was detected by cell counting kit-8 (CCK-8) and colony formation assays. Cell migration and invasion were tested by transwell assay. Moreover, Western blot (WB) analysis was used to test the levels of proliferation and metastasis-related protein, as well as the HMGB1 protein. Besides, mice xenograft models were constructed to assess the effect of circLPAR3 on ESCC tumor growth in vivo. In addition, dual-luciferase reporter and RNA pull-down assays were used to identify the mechanism of circLPAR3.

Results

CircLPAR3 was upregulated in ESCC tissues and cells, and its high expression was related to the poor prognosis of ESCC patients. CircLPAR3 was a stable cyclic transcript, mainly located in the cytoplasm, and its knockdown hindered the proliferation, migration and invasion of ESCC cells and inhibited ESCC tumor growth in vivo. MiR-375/miR-433 could be sponged by circLPAR3, and their inhibitors could reverse the suppression effect of silenced circLPAR3 on ESCC progression. HMGB1 could be targeted by miR-375/miR-433, and its overexpression also could invert the inhibition effect of circLPAR3 knockdown on ESCC progression.

Conclusion

CircLPAR3 might play an oncogenic role in ESCC through sponging miR-375/miR-433 to promote HMGB1 expression, which might provide a theoretical basis for circLPAR3 to become a biomarker for ESCC therapy.

SNCG promotes the progression and metastasis of high-grade serous ovarian cancer via targeting the PI3K/AKT signaling pathway

Background

The poor prognosis of patients with ovarian cancer is mainly due to cancer progression. γ-Synuclein (SNCG) has reported as a critical player in cancer metastasis. However, its biological roles and mechanism are yet incompletely understood in ovarian cancer, especially in high-grade serous ovarian cancer (HGSOC).

Methods

This is a retrospective study of 312 patients with ovarian cancer at a single center between 2006 and 2016. Ovarian cancer tissues were stained by immunohistochemistry to analyze the relationship between SNCG expression and clinicopathologic factors. The clinical outcomes versus SNCG expression level were evaluated by Kaplan–Meier method and multiple Cox regression analysis. Next, systematical functional experiments were given to examine the proliferation and metastatic abilities of SNCG both in vitro and in vivo using loss- and gain- of function approaches. Furthermore, the mechanisms of SNCG overexpression were examined by human phospho-kinase array kit and western blot analysis.

Results

Clinically, the expression of SNCG was significantly upregulated in ovarian cancer compared with the borderline and benign tumor, normal ovary, and fallopian tube. Notably, the high level of SNCG correlated with high-risk clinicopathologic features and showed poor survival for patients with HGSOC, indicating an independent prognostic factor for these patients. Functionally, we observed that overexpression of SNCG promoted cell proliferation, tumor formation, migration, and invasion both in vitro and in vivo. Mechanistically, we identified that SNCG promoted cancer cell metastasis through activating the PI3K/AKT signaling pathway.

Conclusions

Our results reveal SNCG up-regulation contributes to the poor clinical outcome of patients with HGSOC and highlight the metastasis-promoting function of SNCG via activating the PI3K/Akt signaling pathway in HGSOC.

HMGB1 regulates SNAI1 during NSCLC metastasis, both directly, through transcriptional activation, and indirectly, in a RSF1-IT2-dependent manner

High-mobility group protein B1 (HMGB1) has important functions in cancer cell proliferation and metastasis. However, the mechanisms of HMGB1 function in non-small-cell lung cancer (NSCLC) remain unclear. This study aimed to investigate the underlying mechanism of HMGB1-dependent tumor cell proliferation and NSCLC metastasis. Firstly, we found high HMGB1 expression in NSCLC and showed that HMBG1 promoted proliferation, migration, and invasion of NSCLC cells. HMGB1 could bind to SNAI1 promoter and activate the expression of SNAI1. In addition, HMGB1 could transcriptionally regulate the lncRNA RSF1-IT2. RSF1-IT2 was found to function as ceRNA, sponging miR-129-5p, which targets SNAI1. Notably, HMGB1 was also identified as a target of miR-129-5p, which indicates the establishment of a positive feedback loop. Consequently, high expression of RSF1-IT2 and SNAI1 was found to closely correlate with tumor progression in both HMGB1-overexpressing xenograft nude mice and patients with NSCLC. Taken together, our findings provide new insights into molecular mechanisms of HMGB1-dependent tumor metastasis. Components of the HMGB1-RSF1-IT2-miR-129-5p-SNAI1 pathway may have a potential as prognostic and therapeutic targets in NSCLC.

HMGB1 release promotes paclitaxel resistance in castration-resistant prostate cancer cells via activating c-Myc expression

Paclitaxel (PTX) is one of standard chemotherapy drug for patients with metastatic castration-resistant prostate cancer (mCRPC). However, PTX resistance leads to treatment failures, for which the underlying molecular mechanisms remain exclusive. In this study, we reported that PTX-induced constant HMGB1 expression and release confers to PTX resistance in mCRPC cells via activating and sustaining c-Myc signaling. PTX upregulated HMGB1 expression and triggered its release in human mCRPC cells. Silencing HMGB1 by RNAi and blocking HMGB1 release by glycyrrhizin or HMGB1 neutralizing antibody sensitized the response of PTX-resistant mCRPC cells to PTX. Release HMGB1 activated c-Myc expression. Inhibiting c-Myc expression by RNAi or c-MyC inhibitor significantly enhance the sensitivity of PTX-resistant CRPC cells to PTX. Therefore, HMGB1/c-Myc axis is critical in the development of PTX resistance, and targeting HMGB1/c-Myc axis would counteract PTX resistance in mCRPC cells.

Self-enforcing HMGB1/NF-κB/HIF-1α Feedback Loop Promotes Cisplatin Resistance in Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is ranked the sixth most common cancer and the fourth leading cause of cancer-related death worldwide, and its incidence is expected to increase in the future. Cisplatin has been widely used in chemotherapy and transarterial chemoembolization in treatment for HCC. However, the main obstacle to the clinical use of cisplatin is the development of resistance, the mechanisms of which are poorly defined. Therefore, it is imperative to investigate the cellular mechanisms mediating cisplatin resistance in HCC. Here, we demonstrated that high mobility group box 1 (HMGB1) is upregulated in patients with cancer, and implicated in a tumor-supportive role. Further, we showed that HMGB1 has an important role in mediating cisplatin resistance via an HMGB1/ nuclear factor kappa-B (NF-κB)/ hypoxia inducible factor-1α (HIF-1α) feedback loop. The study findings reveal an unappreciated molecular mechanism of HMGB1-mediated cisplatin resistance and may provide a new clue in cancer therapy.

MIR-140-5p affects chondrocyte proliferation, apoptosis, and inflammation by targeting HMGB1 in osteoarthritis

OBJECTIVE

This study aimed to test the expression and biological function of miR-140-5p in osteoarthritis (OA), and identify its target gene and explore its mechanism in OA.

METHODS

Differential genes were screened and analyzed by gene microarray and WGCNA analysis. The normal human chondrocytes C28/I2 were induced by IL-1β to construct the OA cell model. The expression of miR-140-5p and high mobility group box 1 (HMGB1) was quantified by quantitative real-time PCR (qRT-PCR) in OA tissues and IL-1β-induced chondrocytes. Western blotting was performed to evaluate the expression of HMGB1 and PI3K/AKT pathway activation. The concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-6, MMP-1 and MMP-3 were determined by ELISA. CCK-8 and flow cytometry were conducted to determine the cellular capabilities of proliferation and cell apoptosis.

RESULTS

Bioinformatics analysis demonstrated that HMGB1 was highly expressed in OA and activated PI3K/AKT pathway. Also, HMGB1 was predicted as a target of miR-140-5p. The levels of miR-140-5p were negatively correlated with HMGB1 in OA tissues and IL-1β-induced chondrocytes. The overexpression of miR-140-5p reduced the expression of HMGB1 protein, p-AKT (Ser473) and p-PI3K in IL-1β-induced chondrocytes. Besides, the expression of p-AKT (Ser473) and p-PI3K was significantly upregulated by employing miR-140-5p inhibitor, but retrieved after treating with LY294002. Furthermore, miR-140-5p inhibited inflammation, matrix metalloprotease expression and apoptosis in IL-1β-induced chondrocytes through regulating HMGB1.

CONCLUSION

MiR-140-5p was down-regulated while HMGB1 was upregulated in OA. MiR-140-5p could inhibit the PI3K/AKT signaling pathway and suppress the progression of OA through targeting HMGB1.