The protease-inhibitor SerpinB3 as a critical modulator of the stem-like subset in human cholangiocarcinoma

SerpinB3: A Multifaceted Player in Health and Disease-Review and Future Perspectives

SerpinB3, a member of the serine-protease inhibitor family, has emerged as a crucial player in various physiological and pathological processes. Initially identified as an oncogenic factor in squamous cell carcinomas, SerpinB3's intricate involvement extends from fibrosis progression and cancer to cell protection in acute oxidative stress conditions. This review explores the multifaceted roles of SerpinB3, focusing on its implications in fibrosis, metabolic syndrome, carcinogenesis and immune system impairment. Furthermore, its involvement in tissue protection from oxidative stress and wound healing underscores its potential as diagnostic and therapeutic tool. Recent studies have described the therapeutic potential of targeting SerpinB3 through its upstream regulators, offering novel strategies for cancer treatment development. Overall, this review underscores the importance of further research to fully elucidate the mechanisms of action of SerpinB3 and to exploit its therapeutic potential across various medical conditions.

Targeted silencing of SOCS1 by DNMT1 promotes stemness of human liver cancer stem-like cells

BACKGROUND

Human liver cancer stem-like cells (HLCSLCs) are widely acknowledged as significant factors in the recurrence and eradication of hepatocellular carcinoma (HCC). The sustenance of HLCSLCs' stemness is hypothesized to be intricately linked to the epigenetic process of DNA methylation modification of genes associated with anticancer properties. The present study aimed to elucidate the stemness-maintaining mechanism of HLCSLCs and provide a novel idea for the clearance of HLCSLCs.

METHODS

The clinical relevance of DNMT1 and SOCS1 in hepatocellular carcinoma (HCC) patients was evaluated through the GEO and TCGA databases. Cellular immunofluorescence assay, methylation-specific PCR, chromatin immunoprecipitation were conducted to explore the expression of DNMT1 and SOCS1 and the regulatory relationship between them in HLCSLCs. Spheroid formation, soft agar colony formation, expression of stemness-associated molecules, and tumorigenicity of xenograft in nude mice were used to evaluate the stemness of HLCSLCs.

RESULTS

The current analysis revealed a significant upregulation of DNMT1 and downregulation of SOCS1 in HCC tumor tissues compared to adjacent normal liver tissues. Furthermore, patients exhibiting an elevated DNMT1 expression or a reduced SOCS1 expression had low survival. This study illustrated the pronounced expression and activity of DNMT1 in HLCSLCs, which effectively targeted the promoter region of SOCS1 and induced hypermethylation, consequently suppressing the expression of SOCS1. Notably, the stemness of HLCSLCs was reduced upon treatment with DNMT1 inhibitors in a concentration-dependent manner. Additionally, the overexpression of SOCS1 in HLCSLCs significantly mitigated their stemness. The knockdown of SOCS1 expression reversed the effect of DNMT1 inhibitor on the stemness of HLCSLCs. DNMT1 directly binds to the SOCS1 promoter. In vivo, DNMT1 inhibitors suppressed SOCS1 expression and inhibited the growth of xenograft.

CONCLUSION

DNMT1 targets the promoter region of SOCS1, induces hypermethylation of its CpG islands, and silences its expression, thereby promoting the stemness of HLCSLCs.

YBX1 promotes stemness and cisplatin insensitivity in intrahepatic cholangiocarcinoma via the AKT/β-catenin axis

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive malignancy characterized by a poor prognosis and closely linked to tumor stemness. However, the key molecules that regulate ICC stemness remain elusive. Although Y-box binding protein 1 (YBX1) negatively affects prognosis in various cancers by enhancing stemness and chemoresistance, its effect on stemness and cisplatin sensitivity in ICC remains unclear.

METHODS

Three bulk and single-cell RNA-seq datasets were analyzed to investigate YBX1 expression in ICC and its association with stemness. Clinical samples and colony/sphere formation assays validated the role of YBX1 in stemness and sensitivity to cisplatin. AZD5363 and KYA1979K explored the interaction of YBX1 with the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) and WNT/β-catenin pathways.

RESULTS

YBX1 was significantly upregulated in ICC, correlated with worse overall survival and shorter postoperative recurrence time, and was higher in chemotherapy-non-responsive ICC tissues. The YBX1-high group exhibited significantly elevated stemness scores, and genes linked to YBX1 upregulation were enriched in multiple stemness-related pathways. Moreover, YBX1 expression is significantly correlated with several stemness-related genes (SOX9, OCT4, CD133, CD44 and EPCAM). Additionally, YBX1 overexpression significantly enhanced the colony- and spheroid-forming abilities of ICC cells, accelerated tumor growth in vivo and reduced their sensitivity to cisplatin. Conversely, the downregulation of YBX1 exerted the opposite effect. The transcriptomic analysis highlighted the link between YBX1 and the PI3K/AKT and WNT/β-catenin pathways. Further, AZD5363 and KYA1979K were used to clarify that YBX1 promoted ICC stemness through the regulation of the AKT/β-catenin axis.

CONCLUSIONS

YBX1 is upregulated in ICC and promotes stemness and cisplatin insensitivity via the AKT/β-catenin axis. Our study describes a novel potential therapeutic target for improving ICC prognosis.

SerpinB3/4 Expression Is Associated with Poor Prognosis in Patients with Cholangiocarcinoma

Cholangiocarcinoma (CCA), the second most common primary liver tumor, is associated with a dismal outcome, and useful prognostic markers are not currently available in clinical practice. SerpinB3, a serine protease inhibitor, was recently found to play a relevant role in malignant transformation in different cancers. The aim of the present study was to determine the expression of SerpinB3/4 in tissue and serum samples of patients with CCA in relation to clinical outcomes. SerpinB3/4 was assessed in the tissue microarrays (TMAs) of 123 surgically resected CCAs. ELISA assays were carried out in 188 patients with CCA to detect the free and IgM-linked forms of SerpinB3/4. Overall survival was analyzed in relation to SerpinB3/4 expression, and Cox models were used to identify the variables associated with survival. High levels of SerpinB3/4 (TMA score 2+/3+) were detected in 15 tumors (12.2%), characterized by a more advanced TNM stage (III/IV: 64.3% vs. 31.3%; p = 0.031) and lower overall patient survival, independently of CCA subclass (intrahepatic CCA: median 1.1 (0.8-Not Estimable, NE) vs. 2.4 (1.8-3.4) years; p = 0.0007; extrahepatic CCA: median 0.8 (0.2-NE) vs. 2.2 (1.5-5.4) years; p = 0.011). Vascular invasion (p = 0.027) and SerpinB3/4 scores (p = 0.0016) were independently associated with mortality in multivariate analysis. Patients who had detectable free or IgM-linked SerpinB3/4 in their serum showed poorer survival (1 vs. 2.4 years, p = 0.015, for free SerpinB3/4, and 1 vs. 2.6 years, p = 0.0026, for SerpinB3/4-IgM). In conclusion, high levels of SerpinB3/4 in tissue and serum in CCA are associated with poor outcomes after surgery, regardless of tumor subclass.

SERPINB3-MYC axis induces the basal-like/squamous subtype and enhances disease progression in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) exhibits distinct molecular subtypes: classical/progenitor and basal-like/squamous. Our study aimed to identify genes contributing to the development of the basal-like/squamous subtype, known for its aggressiveness. Transcriptome analyses revealed consistent upregulation of SERPINB3 in basal-like/squamous PDAC, correlating with reduced patient survival. SERPINB3 transgene expression in PDAC cells enhanced in vitro invasion and promoted lung metastasis in a mouse PDAC xenograft model. Metabolome analyses unveiled a metabolic signature linked to both SERPINB3 and the basal-like/squamous subtype, characterized by heightened carnitine/acylcarnitine and amino acid metabolism, associated with poor prognosis in patients with PDAC and elevated cellular invasiveness. Further analysis uncovered that SERPINB3 inhibited the cysteine protease calpain, a key enzyme in the MYC degradation pathway, and drove basal-like/squamous subtype and associated metabolic reprogramming through MYC activation. Our findings indicate that the SERPINB3-MYC axis induces the basal-like/squamous subtype, proposing SERPINB3 as a potential diagnostic and therapeutic target for this variant.

Identification and validation of a dysregulated TME-related gene signature for predicting prognosis, and immunological properties in bladder cancer

Background

During tumor growth, tumor cells interact with their tumor microenvironment (TME) resulting in the development of heterogeneous tumors that promote tumor occurrence and progression. Recently, there has been extensive attention on TME as a possible therapeutic target for cancers. However, an accurate TME-related prediction model is urgently needed to aid in the assessment of patients' prognoses and therapeutic value, and to assist in clinical decision-making. As such, this study aimed to develop and validate a new prognostic model based on TME-associated genes for BC patients.

Methods

Transcriptome data and clinical information for BC patients were extracted from The Cancer Genome Atlas (TCGA) database. Gene Expression Omnibus (GEO) and IMvigor210 databases, along with the MSigDB, were utilized to identify genes associated with TMEs (TMRGs). A consensus clustering approach was used to identify molecular clusters associated with TMEs. LASSO Cox regression analysis was conducted to establish a prognostic TMRG-related signature, with verifications being successfully conducted internally and externally. Gene ontology (GO), KEGG, and single-sample gene set enrichment analyses (ssGSEA) were performed to investigate the underlying mechanisms. The potential response to ICB therapy was estimated using the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm and Immunophenoscore (IPS). Additionally, it was found that the expression level of certain genes in the model was significantly correlated with objective responses to anti-PD-1 or anti-PD-L1 treatment in the IMvigor210, GSE111636, GSE176307, or Truce01 (registration number NCT04730219) cohorts. Finally, real-time PCR validation was performed on 10 paired tissue samples, and in vitro cytological experiments were also conducted on BC cell lines.

Results

In BC patients, 133 genes differentially expressed that were associated with prognosis in TME. Consensus clustering analysis revealed three distinct clinicopathological characteristics and survival outcomes. A novel prognostic model based on nine TMRGs (including C3orf62, DPYSL2, GZMA, SERPINB3, RHCG, PTPRR, STMN3, TMPRSS4, COMP) was identified, and a TMEscore for OS prediction was constructed, with its reliable predictive performance in BC patients being validated. MultiCox analysis showed that the risk score was an independent prognostic factor. A nomogram was developed to facilitate the clinical viability of TMEscore. Based on GO and KEGG enrichment analyses, biological processes related to ECM and collagen binding were significantly enriched among high-risk individuals. In addition, the low-risk group, characterized by a higher number of infiltrating CD8+ T cells and a lower burden of tumor mutations, demonstrated a longer survival time. Our study also found that TMEscore correlated with drug susceptibility, immune cell infiltration, and the prediction of immunotherapy efficacy. Lastly, we identified SERPINB3 as significantly promoting BC cells migration and invasion through differential expression validation and in vitro phenotypic experiments.

Conclusion

Our study developed a prognostic model based on nine TMRGs that accurately and stably predicted survival, guiding individual treatment for patients with BC, and providing new therapeutic strategies for the disease.

Fumagillin regulates stemness and malignancies in cancer stem-like cells derived from liver cancer via targeting to MetAP-2

BACKGROUND

Cancer relapse is associated with the presence of cancer stem-like cells (CSCs), which lead to multidirectional differentiation and unrestricted proliferative replication. Fumagillin, a myocotoxin produced by the saprophytic filamentous fungus Aspergillus fumigatus, has been reported to affect malignant characteristics in hepatocellular cancer cells. However, its exact role in CSCs is still unknown.

METHODS

CSCs were enriched by culturing cancer cells in serum-free medium. The effects of fumagillin on malignant cell characteristics and mitochondrial function were measured. The regulatory role of fumagillin on methionine aminopeptidase-2 (MetAP-2) was assessed.

RESULTS

When it was supplemented in medium, fumagillin treatment inhibited sphere formation and the maintenance of stemness of CSCs without disturbing cell growth. Fumagillin also decreased stemness-related markers and the aldehyde dehydrogenase 1 (ALDH1)-positive proportion, which demonstrated that fumagillin decreases stemness in CSCs. It was also found to inhibit malignant traits in CSCs, including cell proliferation, invasion, and tumor formation, and sensitize CSCs to chemoagents, including sorafenib and doxorubicin, by promoting chemoagent-induced apoptosis. Moreover, fumagillin treatment was found to disturb mitochondrial membrane homeostasis, ATP synthesis and mitochondrial transcriptional activity. In addition, we found that fumagillin decreased MetAP-2 protein levels and exerted anti-CSC effects potentially by regulating MetAP-2. We also found that fumagillin treatment activated p53 and its transcriptional activity and thus caused cell cycle blockade. Moreover, fumagillin treatment significantly decreased tumor formation in nude mice.

CONCLUSION

This work offers evidence for fumagillin as a specific inhibitor of liver cancer CSCs and proposes a novel strategy for cancer therapy.

Novel Molecular Targets for Immune Surveillance of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common and aggressive cancer with a high mortality rate. The incidence of HCC is increasing worldwide, and the lack of effective screening programs often results in delayed diagnosis, making it a challenging disease to manage. Immunotherapy has emerged as a promising treatment option for different kinds of cancers, with the potential to stimulate the immune system to target cancer cells. However, the current immunotherapeutic approaches for HCC have shown limited efficacy. Since HCC arises within a complex tumour microenvironment (TME) characterized by the presence of various immune and stromal cell types, the understanding of this interaction is crucial for the identification of effective therapy. In this review, we highlight recent advances in our understanding of the TME of HCC and the immune cells involved in anti-tumour responses, including the identification of new possible targets for immunotherapy. We illustrate a possible classification of HCC based on the tumour immune infiltration and give evidence about the role of SerpinB3, a serine protease inhibitor involved in the regulation of the immune response in different cancers.

SerpinB3 Upregulates Low-Density Lipoprotein Receptor-Related Protein (LRP) Family Members, Leading to Wnt Signaling Activation and Increased Cell Survival and Invasiveness

Abnormal activation of the Wnt-β-catenin signaling cascade is involved in tumor growth and dissemination. SerpinB3 has been shown to induce β-catenin, and both molecules are overexpressed in tumors, particularly in those with poor prognoses. The aim of this study was to evaluate the ability of SerpinB3 to modulate the Wnt pathway in liver cancer and in monocytic cells, the main type of inflammatory cells in the tumor microenvironment. The Wnt cascade, Wnt co-receptors, and low-density lipoprotein receptor-related protein (LRP) members were analyzed in different cell lines and human monocytes in the presence or absence of SerpinB3. The Wnt-β-catenin axis was also evaluated in liver tumors induced in mice with different extents of SeprinB3 expression. In monocytic cells, SerpinB3 induced a significant upregulation of Wnt-1/7, nuclear β-catenin, and c-Myc, which are associated with increased cell lifespan and proliferation. In liver tumors in mice, the expression of β-catenin was significantly correlated with the presence of SerpinB3. In hepatoma cells, Wnt co-receptors LRP-5/6 and LRP-1, implicated in cell survival and invasiveness, were upregulated by SerpinB3. The LRP pan-inhibitor RAP not only induced a decrease in LRP expression, but also a dose-dependent reduction in SerpinB3-induced invasiveness. In conclusion, SerpinB3 determines the activation of the Wnt canonical pathway and cell invasiveness through the upregulation of LRP family members.

Epitope-Specific Anti-SerpinB3 Antibodies for SerpinB3 Recognition and Biological Activity Inhibition

SerpinB3 is a serine protease inhibitor that plays a relevant role in disease progression and cancer by increasing fibrosis, cell proliferation, and invasion, besides conferring resistance to apoptosis. The mechanisms underlying these biological activities are not yet fully understood. The aim of this study was to generate antibodies directed against different SerpinB3 epitopes to better investigate their biological role. Five exposed epitopes were identified using the software DNASTAR Lasergene and the corresponding synthetic peptides were used for NZW rabbit immunization. Anti-P#2 and anti-P#4 antibodies were able to recognize both SerpinB3 and SerpinB4 by ELISA. Anti-P#5 antibody, produced against the reactive site loop of SerpinB3, showed the greatest specific reactivity for human SerpinB3. This antibody was able to recognize SerpinB3 at nuclear level, while anti-P#3 antibody recognized SerpinB3 only at cytoplasmic level, both by immunofluorescence and by immunohistochemistry. The biological activity of each antibody preparation was assessed in HepG2 cells overexpressing SerpinB3 and anti-P#5 antibody reduced proliferation by 12% cell and cell invasion by 75%, while trivial results were obtained with the other antibody preparations. These findings indicate that the reactive site loop of SerpinB3 is essential for the invasiveness features induced by this serpin and it could become a novel druggable target.

SERPINB3, Adult-Onset Immunodeficiency, and Generalized Pustular Psoriasis

BACKGROUND

Generalized pustular psoriasis (GPP; MIM 614204) is a rare and severe pustular autoinflammatory skin disease in which acute generalized erythema and scaling develop with numerous sterile pustules. GPP shares skin manifestations, especially pustular skin reaction, with adult-onset immunodeficiency (AOID) with anti-interferon-γ autoantibodies, an autoimmune disease.

METHODS

Clinical examinations and whole-exome sequencing (WES) were performed on 32 patients with pustular psoriasis phenotypes and 21 patients with AOID with pustular skin reaction. Immunohistochemical and histopathological studies were performed.

RESULTS

WES identified three Thai patients presenting with similar pustular phenotypes-two with a diagnosis of AOID and the other with GPP. A heterozygous missense variant chr18:g.61325778C>A NM_006919.2: c.438G>T; NP_008850.1: p.Lys146Asn; rs193238900 in SERPINB3 was identified in two patients: one with GPP and the other with AOID. The other patient who had AOID carried a heterozygous missense variant chr18:g.61323147T>C NM_006919.2: c.917A>G; NP_008850.1: p.Asp306Gly in SERPINB3. Immunohistochemical studies showed overexpression of SERPINA1 and SERPINB3, a hallmark of psoriatic skin lesions.

CONCLUSIONS

Genetic variants in SERPINB3 are associated with GPP and AOID with pustular skin reaction. The skin of patients with GPP and AOID carrying SERPINB3 mutations showed overexpression of SERPINB3 and SERPINA1. Clinically and genetically, GPP and AOID appear to share pathogenetic mechanisms.

SerpinB3 administration protects liver against ischemia-reperfusion injury

We have investigated the change in SerpinB3 during hepatic ischemia and the potential role of its antiprotease activity in cell protection by the administration of wild-type SerpinB3 (SerpinB3-WT) or active loop-deleted recombinant SerpinB3 protein (SerpinB3-D) in a rat model of ischemia (60 min)/reperfusion (60 min) (I/R). A time-dependent increase of SerpinB3, both at transcription and protein level, was found in ischemic livers after 60, 120 and 180 min. SerpinB3-WT decreased polymorphonuclear cell infiltration and serum enzymes and increased ATP when compared with I/R group. These events were not obtained using SerpinB3-D. No significant changes in both liver SerpinB3 mRNA and protein were found in all I/R groups considered. The present data show that the administration of SerpinB3-WT reduced the I/R injury and this effect appears to be dependent on its anti-protease activity.  

SerpinB3 drives cancer stem cell survival in glioblastoma

Despite therapeutic interventions for glioblastoma (GBM), cancer stem cells (CSCs) drive recurrence. The precise mechanisms underlying CSC resistance, namely inhibition of cell death, are unclear. We built on previous observations that the high cell surface expression of junctional adhesion molecule-A drives CSC maintenance and identified downstream signaling networks, including the cysteine protease inhibitor SerpinB3. Using genetic depletion approaches, we found that SerpinB3 is necessary for CSC maintenance, survival, and tumor growth, as well as CSC pathway activation. Knockdown of SerpinB3 also increased apoptosis and susceptibility to radiation therapy. SerpinB3 was essential to buffer cathepsin L-mediated cell death, which was enhanced with radiation. Finally, we found that SerpinB3 knockdown increased the efficacy of radiation in pre-clinical models. Taken together, our findings identify a GBM CSC-specific survival mechanism involving a cysteine protease inhibitor, SerpinB3, and provide a potential target to improve the efficacy of GBM therapies against therapeutically resistant CSCs.

BMI1 promotes cholangiocarcinoma progression and correlates with antitumor immunity in an exosome-dependent manner

BACKGROUND

Cholangiocarcinoma (CCA) is a class of malignant tumors originating from bile duct epithelial cells. Due to difficult early diagnosis and limited treatment, the prognosis of CCA is extremely poor. BMI1 is dysregulated in many human malignancies. However, the prognostic significance and oncogenic role of BMI1 in cholangiocarcinoma (CCA) are not well elucidated.

METHODS

In the present study, we investigated its clinical importance and the potential mechanisms in the progression of CCA. We detected BMI1 expression in a large CCA cohort. We demonstrated that BMI1 was substantially upregulated in CCA tissues and was identified as an independent prognostic biomarker of CCA. Moreover, overexpression of BMI1 promoted CCA proliferation, migration, and invasion. And BMI1 knockdown could inhibit proliferation and metastases of CCA in vitro and in vitro/vivo validation. Interestingly, we found that CCA-derived exosomes contain BMI1 proteins, which can transfer BMI1 between CCA cells. The unique BMI1-containing exosomes promote CCA proliferation and metastasis through autocrine/paracrine mechanisms. In addition, we demonstrated that BMI1 inhibits CD8+T cell-recruiting chemokines by promoting repressive H2A ubiquitination in CCA cells.

CONCLUSIONS

BMI1 is an unfavorable prognostic biomarker of CCA. Our data depict a novel function of BMI1 in CCA tumorigenesis and metastasis mediated by exosomes. Besides, BMI1 inhibition may augment immune checkpoint blockade to inhibit tumor progression by activating cell-intrinsic immunity of CCA.

Targeting Src-Hic-5 Signal Cascade for Preventing Migration of Cholangiocarcinoma Cell HuCCT1

Cholangiocarcinoma (CCA) is the second most common primary liver cancer with poor prognosis. The deregulation of a lot of oncogenic signaling molecules, such as receptor tyrosine kinases (RTKs), has been found to be associated with CCA progression. However, RTKs-based target therapy showed limited improvement suggesting a need to search for alternative targets for preventing CCA progression. To address this issue, we screened the oncogenic signal molecules upregulated in surgical tissues of CCAs. Interestingly, over-expression of hydrogen peroxide inducible clone-5 (Hic-5) coupled with over-activation of Src, AKT, JNK were observed in 50% of the cholangiocarcinoma with metastatic potential. To investigate whether these molecules may work together to trigger metastatic signaling, their up-and-down relationship was examined in a well-established cholangiocarcinoma cell line, HuCCT1. Src inhibitors PP1 (IC50, 13.4 μM) and dasatinib (IC50, 0.1 μM) significantly decreased both phosphorylated AKT (phosphor-AKT Thr450) and Hic-5 in HuCCT1. In addition, a knockdown of Hic-5 effectively suppressed activation of Src, JNK, and AKT. These implicated a positive cross-talk occurred between Hic-5 and Src for triggering AKT activation. Further, depletion of Hic-5 and inhibition of Src suppressed HuccT1 cell migration in a dose-dependent manner. Remarkably, prior transfection of Hic-5 siRNA for 24 h followed by treatment with PP1 or dasatinib for 24 h resulted in additive suppression of HuCCT1 migration. This suggested that a promising combinatory efficacy can be achieved by depletion of Hic-5 coupled with inhibition of Src. In the future, target therapy against CCA progression by co-targeting Hic-5 and Src may be successfully developed in vivo.