SCCA1/SERPINB3 promotes oncogenesis and epithelial-mesenchymal transition via the unfolded protein response and IL6 signaling

ZDHHC9-mediated Bip/GRP78 S-palmitoylation inhibits unfolded protein response and promotes bladder cancer progression

Recent studies have highlighted palmitoylation, a novel protein post-translational modification, as a key player in various signaling pathways that contribute to tumorigenesis and drug resistance. Despite this, its role in bladder cancer (BCa) development remains inadequately understood. In this study, ZDHHC9 emerged as a significantly upregulated oncogene in BCa. Functionally, ZDHHC9 knockdown markedly inhibited tumor proliferation, promoted tumor cell apoptosis, and enhanced the efficacy of gemcitabine (GEM) and cisplatin (CDDP). Mechanistically, SP1 was found to transcriptionally activate ZDHHC9 expression. ZDHHC9 subsequently bound to and palmitoylated the Bip protein at cysteine 420 (Cys420), thereby inhibiting the unfolded protein response (UPR). This palmitoylation at Cys420 enhanced Bip's protein stability and preserved its localization within the endoplasmic reticulum (ER). ZDHHC9 might become a novel therapeutic target for BCa and could also contribute to combination therapy with GEM and CDDP.

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.

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.

An Early Neoplasia Index (ENI10), Based on Molecular Identity of CD10 Cells and Associated Stemness Biomarkers, is a Predictor of Patient Outcome in Many Cancers

An accurate estimate of patient survival at diagnosis is critical to plan efficient therapeutic options. A simple and multiapplication tool is needed to move forward the precision medicine era. Taking advantage of the broad and high CD10 expression in stem and cancers cells, we evaluated the molecular identity of aggressive cancer cells. We used epithelial primary cells and developed a breast cancer stem cell–based progressive model. The superiority of the early-transformed isolated molecular index was evaluated by large-scale analysis in solid cancers. BMP2-driven cell transformation increases CD10 expression which preserves stemness properties. Our model identified a unique set of 159 genes enriched in G2–M cell-cycle phases and spindle assembly complex. Using samples predisposed to transformation, we confirmed the value of an early neoplasia index associated to CD10 (ENI10) to discriminate premalignant status of a human tissue. Using a stratified Cox model, a large-scale analysis (>10,000 samples, The Cancer Genome Atlas Pan-Cancer) validated a strong risk gradient (HRs reaching HR = 5.15; 95% confidence interval: 4.00–6.64) for high ENI10 levels. Through different databases, Cox regression model analyses highlighted an association between ENI10 and poor progression-free intervals for more than 50% of cancer subtypes tested, and the potential of ENI10 to predict drug efficacy. The ENI10 index constitutes a robust tool to detect pretransformed tissues and identify high-risk patients at diagnosis. Owing to its biological link with refractory cancer stem cells, the ENI10 index constitutes a unique way of identifying effective treatments to improve clinical care.

SIGNIFICANCE

We identified a molecular signature called ENI10 which, owing to its biological link with stem cell properties, predicts patient outcome and drugs efficiency in breast and several other cancers. ENI10 should allow early and optimized clinical management of a broad number of cancers, regardless of the stage of tumor progression.

SerpinB3 as hepatic marker of post-resective shear stress

Post-resective liver failure is a frequent complication of liver surgery and it is due to portal hyperperfusion of the remnant liver and to arterial vasoconstriction, as buffer response of the hepatic artery. In this context, splenectomy allows a reduction of portal flow and increases the survival chance in preclinical models. SerpinB3 is over-expressed in the liver in oxidative stress conditions, as a mechanism of cell defense to provide survival by apoptosis inhibition and cell proliferation. In this study, the expression of SerpinB3 was assessed as predictor of liver damage in in vivo models of major hepatic resection with or without splenectomy. Wistar male rats were divided into 4 groups: group A received 30% hepatic resection, group B > 60% resection, group C > 60% resection with splenectomy and group D sham-operated. Before and after surgery liver function tests, echo Doppler ultrasound and gene expression were assessed. Transaminase values and ammonium were significantly higher in groups that underwent major hepatic resection. Echo Doppler ultrasound showed the highest portal flow and resistance of the hepatic artery in the group with > 60% hepatectomy without splenectomy, while the association of splenectomy determined no increase in portal flow and hepatic artery resistance. Only the group of rats without splenectomy showed higher shear-stress conditions, reflected by higher levels of HO-1, Nox1 and of Serpinb3, the latter associated with an increase of IL-6. In conclusion, splenectomy controls inflammation and oxidative damage, preventing the expression of Serpinb3. Therefore, SerpinB3 can be considered as a marker of post-resective shear stress.

Taxifolin Inhibits Breast Cancer Growth by Facilitating CD8+ T Cell Infiltration and Inducing a Novel Set of Genes including Potential Tumor Suppressor Genes in 1q21.3

Taxifolin inhibits breast cancer (BC) via novel mechanisms. In a syngeneic mouse BC model, taxifolin suppressed 4T-1 cell-derived allografts. RNA-seq of 4T-1 tumors identified 36 differentially expressed genes (DEGs) upregulated by taxifolin. Among their human homologues, 19, 7, and 2 genes were downregulated in BCs, high-proliferative BCs, and BCs with high-fatality risks, respectively. Three genes were established as tumor suppressors and eight were novel to BC, including HNRN, KPRP, CRCT1, and FLG2. These four genes exhibit tumor suppressive actions and reside in 1q21.3, a locus amplified in 70% recurrent BCs, revealing a unique vulnerability of primary and recurrent BCs with 1q21.3 amplification with respect to taxifolin. Furthermore, the 36 DEGs formed a multiple gene panel (DEG36) that effectively stratified the fatality risk in luminal, HER2+, and triple-negative (TN) equivalent BCs in two large cohorts: the METABRIC and TCGA datasets. 4T-1 cells model human TNBC cells. The DEG36 most robustly predicted the poor prognosis of TNBCs and associated it with the infiltration of CD8+ T, NK, macrophages, and Th2 cells. Of note, taxifolin increased the CD8+ T cell content in 4T-1 tumors. The DEG36 is a novel and effective prognostic biomarker of BCs, particularly TNBCs, and can be used to assess the BC-associated immunosuppressive microenvironment.

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.

SCCA1/SERPINB3 promotes suppressive immune environment via STAT-dependent chemokine production, blunting the therapy-induced T cell responses

Radiotherapy is a commonly used cancer treatment; however, patients with high serum squamous cell carcinoma antigen (SCCA1/SERPINB3) are associated with resistance and poor prognosis. Despite being a strong clinical biomarker, the modulation of SERPINB3 in tumor immunity is poorly understood. We investigated the microenvironment of SERPINB3 high tumors through RNAseq of primary cervix tumors and found that SERPINB3 was positively correlated with CXCL1/8, S100A8/A9 and myeloid cell infiltration. Induction of SERPINB3 in vitro resulted in increased CXCL1/8 and S100A8/A9 production, and supernatants from SERPINB3-expressing cultures attracted monocytes and MDSCs. In murine tumors, the orthologue mSerpinB3a promoted MDSC, TAM, and M2 macrophage infiltration contributing to an immunosuppressive phenotype, which was further augmented upon radiation. Radiation-enhanced T cell response was muted in SERPINB3 tumors, whereas Treg expansion was observed. A STAT-dependent mechanism was implicated, whereby inhibiting STAT signaling with ruxolitinib abrogated suppressive chemokine production. Patients with elevated pre-treatment serum SCCA and high pSTAT3 had increased intratumoral CD11b+ myeloid cell compared to patients with low SCCA and pSTAT3 cohort that had overall improved cancer specific survival after radiotherapy. These findings provide a preclinical rationale for targeting STAT signaling in tumors with high SERPINB3 to counteract the immunosuppressive microenvironment and improve response to radiation.

Biomarker Discovery for Meta-Classification of Melanoma Metastatic Progression Using Transfer Learning

Melanoma is considered to be the most serious and aggressive type of skin cancer, and metastasis appears to be the most important factor in its prognosis. Herein, we developed a transfer learning-based biomarker discovery model that could aid in the diagnosis and prognosis of this disease. After applying it to the ensemble machine learning model, results revealed that the genes found were consistent with those found using other methodologies previously applied to the same TCGA (The Cancer Genome Atlas) data set. Further novel biomarkers were also found. Our ensemble model achieved an AUC of 0.9861, an accuracy of 91.05, and an F1 score of 90.60 using an independent validation data set. This study was able to identify potential genes for diagnostic classification (C7 and GRIK5) and diagnostic and prognostic biomarkers (S100A7, S100A7, KRT14, KRT17, KRT6B, KRTDAP, SERPINB4, TSHR, PVRL4, WFDC5, IL20RB) in melanoma. The results show the utility of a transfer learning approach for biomarker discovery in melanoma.

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.

Squamous Cell Carcinoma Antigen: Clinical Application and Research Status

The squamous cell carcinoma antigen (SCCA) is a tumor marker that has gained increasing attention for its biological functions and significance in normal physiological and pathological processes. Not only SCCA but also circulating immune complexes of SCCA and immunoglobulin M (IgM) are involved in normal physiological and pathological processes, providing a background for numerous clinical studies aimed at assessing the potential role of SCCA, SCCA–IgM, and SCCA isoform complexes in clinical practice. Previous studies support the clinical value of SCCA as a tumor marker for either diagnosing squamous cancers or monitoring the response to radiotherapy or chemotherapy, tumor relapse, and treatment failure. However, these studies show contrasting results, making the diagnostic or prognostic value of SCCA controversial. To reduce clinical heterogeneity across studies and achieve a more accurate and reliable comparison of results, a standardized detection method, scoring system, and cutoff level need to be established. Moreover, despite the fact that performances of different methods are comparable, the dynamic observation of tumor marker kinetics should be conducted under the same method.

Hydrogen Sulfide Inhibits Bronchial Epithelial Cell Epithelial Mesenchymal Transition Through Regulating Endoplasm Reticulum Stress

Epithelial mesenchymal transition (EMT) is a contributing factor in remodeling events of chronic obstructive pulmonary disease (COPD). Hydrogen sulfide (H₂S) has been implicated in the pathogenesis of COPD, but the effect of H₂S in regulating EMT and the underlying mechanisms is not clear. In this study, we assessed endoplasmic reticulum (ER) stress markers, EMT markers and associated signal molecules in rat lungs, bronchial epithelial cells, and human peripheral lung tissues to investigate the effect of H₂S in regulating EMT and the underlying mechanisms. We found that EMT and ER stress occurred in lung epithelial cells, especially in the bronchial epithelial cells of smokers and COPD patients. In cigarette smoke (CS)-exposed rats, intraperitoneal injection of NaHS significantly alleviated CS-induced lung tissue damage, small airway fibrosis, ER stress, and EMT, while intraperitoneal injection of propargylglycine (cystathionine-gamma-lyase inhibitor) aggravated these effects induced by CS. In the nicotine-exposed 16HBE cells, an appropriate concentration of H₂S donor not only inhibited nicotine-induced ER stress, but also inhibited nicotine-induced enhancement of cell migration ability and EMT. ER stress nonspecific inhibitors taurine and 4-phenyl butyric acid also inhibited nicotine-induced enhancement of cell migration ability and EMT. Both H2S and inositol-requiring enzyme 1 (IRE1) activation inhibitor 4μ8C inhibited nicotine-induced activation of IRE1, Smad2/3 and EMT. These results suggest that H₂S inhibits CS- or nicotine-induced ER stress and EMT in bronchial epithelial cells and alleviates CS-induced lung tissue damage and small airway fibrosis. The IRE1 signal pathway and Smad2/3 may be responsible for the inhibitory effect of H₂S.

Topical heparin as an effective and safe treatment for patients with capecitabine-induced hand-foot syndrome: results of a phase IIA trial supported by proteomic profiling of skin biopsies

Background:

Hand-foot syndrome (HFS) is a common adverse reaction associated with capecitabine chemotherapy that significantly affects the quality of life of patients. This study evaluates the safety and effectiveness of a topical heparin (TH) treatment on the clinical manifestations and anatomopathological alterations of capecitabine-induced HFS. In addition, we performed proteome profiling of skin biopsies obtained from patients with HFS at baseline and after heparin treatment.

Methods:

Patients with grade ⩽ 2 HFS associated with capecitabine were included in this study. The primary end point was the effectiveness of TH in reducing HFS of any grade. Clinical improvement was evaluated by clinicians, and an improvement was perceived by patients who performed a weekly visual analog scale questionnaire. Secondary end points included a comparative histological analysis and protein expression in skin biopsies at baseline and after 3 weeks of HT treatment. Proteomic profiling was carried out using quantitative isobaric labelling and subsequently validated by a T-array.

Results:

Twenty-one patients were included in the study. The median TH treatment time was 7.6 weeks (range = 3.6–41.6 weeks), and the median response time was 3.01 weeks (95% CI = 2.15–3.97). At the end of treatment, 19 of 21 patients (90.48%) responded to treatment with a decrease in one or more grades of HFS. None of the patients experienced adverse effects related to TH usage, nor did they suspend chemotherapy treatment. The main findings observed in skin biopsies after treatment were a decrease in hyperkeratosis and lymphocytic infiltrates. The proteomic analysis showed altered expression of 34 proteins that were mainly related to wound healing, cell growth, and the immune response.

Conclusion:

Based on our results, topical heparin is an effective and safe treatment for clinical manifestations of HFS, probably due to the restauration of skin homeostasis after heparin treatment, as supported by our proteomics-derived data.

Trial registration:

EudraCT 2009-018171-13

Predicting Response to Neoadjuvant Therapy in Oesophageal Adenocarcinoma

(1) Background: Oesophageal cancers are often late-presenting and have a poor 5-year survival rate. The standard treatment of oesophageal adenocarcinomas involves neoadjuvant chemotherapy with or without radiotherapy followed by surgery. However, less than one third of patients respond to neoadjuvant therapy, thereby unnecessarily exposing patients to toxicity and deconditioning. Hence, there is an urgent need for biomarkers to predict response to neoadjuvant therapy. This review explores the current biomarker landscape. (2) Methods: MEDLINE, EMBASE and ClinicalTrial databases were searched with key words relating to “predictive biomarker”, “neoadjuvant therapy” and “oesophageal adenocarcinoma” and screened as per the inclusion and exclusion criteria. All peer-reviewed full-text articles and conference abstracts were included. (3) Results: The search yielded 548 results of which 71 full-texts, conference abstracts and clinical trials were eligible for review. A total of 242 duplicates were removed, 191 articles were screened out, and 44 articles were excluded. (4) Discussion: Biomarkers were discussed in seven categories including imaging, epigenetic, genetic, protein, immunologic, blood and serum-based with remaining studies grouped in a miscellaneous category. (5) Conclusion: Although promising markers and novel methods have emerged, current biomarkers lack sufficient evidence to support clinical application. Novel approaches have been recommended to assess predictive potential more efficiently.

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

BACKGROUND AND AIMS

Cholangiocarcinoma (CCA) is a form of primary liver cancer with limited therapeutic options. Recently, cancer stem cells (CSCs) have been proposed as a driving force of tumour initiation and dissemination, thus representing a crucial therapeutic target. The protease inhibitor SerpinB3 (SB3) has been identified in several malignancies including hepatocellular carcinoma. SB3 has been involved in the early events of hepatocarcinogenesis and is highly expressed in hepatic progenitor cells and in a mouse model of liver progenitor cell activation. However, only limited information on the possible role of SB3 in CCA stem-like compartment is available.

METHODS

Enrichment of CCA stem-like subset was performed by sphere culture (SPH) in CCA cell lines (CCLP1, HUCCT1, MTCHC01 and SG231). Quantitative RT-PCR and Western blotting were used to detect SB3 in both SPH and parental monolayer (MON) cells. Acquired CSC-like features were analysed using an endogenous and a paracrine in vitro model, with transfection of SB3 gene or addition of recombinant SB3 to cell medium respectively. SB3 tumorigenic role was explored in an in vivo mouse model of CCA by subcutaneous injection of SB3-transfected MON (MONSB3+ ) cells in immune-deficient NOD-SCID/IL2Rgnull  (NSG) mice. SB3 expression in human CCA sections was investigated by immunohistochemistry. Overall survival (OS) and time to recurrence (TTR) analyses were carried out from a transcriptome database of 104 CCA patients.

RESULTS

SB3, barely detected in parental MON cells, was overexpressed in the same CCA cells grown as 3D SPH. Notably, MONSB3+ showed significant overexpression of genes associated with stemness (CD24, CD44, CD133), pluripotency (c-MYC, NOTCH1, STAT3, YAP, NANOG, BMI1, KLF4, OCT4, SOX2), epithelial mesenchymal transition (β-catenin, SLUG) and extracellular matrix remodelling (MMP1, MMP7, MMP9, ADAM9, ADAM10, ADAM17, ITGB3). SB3-overexpressing cells showed superior spherogenic capacity and invasion ability compared to control. Importantly, MONSB3+ exhibited activation of MAP kinases (ERK1/2, p38, JNK) as well as phosphorylation of NFκB (p65) in addition to up-regulation of the proto-oncogene β-catenin. All these effects were reversed after transient silencing of SB3. According to the in vitro finding, MONSB3+ cells retained high tumorigenic potential in NSG mice. SB3 overexpression was observed in human CCA tissues and analysis of OS as well as TTR indicated a worse prognosis in SB3+ CCA patients.

CONCLUSION

These findings indicate a SB3 role in mediating malignant phenotype of CCA and identify a new therapeutic target.

Super-enhancer-associated TMEM44-AS1 aggravated glioma progression by forming a positive feedback loop with Myc

Background

Long non-coding RNAs (lncRNAs) have been considered as one type of gene expression regulator for cancer development, but it is not clear how these are regulated. This study aimed to identify a specific lncRNA that promotes glioma progression.

Methods

RNA sequencing (RNA-seq) and quantitative real-time PCR were performed to screen differentially expressed genes. CCK-8, transwell migration, invasion assays, and a mouse xenograft model were performed to determine the functions of TMEM44-AS1. Co-IP, ChIP, Dual-luciferase reporter assays, RNA pulldown, and RNA immunoprecipitation assays were performed to study the molecular mechanism of TMEM44-AS1 and the downstream target.

Results

We identified a novel lncRNA TMEM44-AS1, which was aberrantly expressed in glioma tissues, and that increased TMEM44-AS1 expression was correlated with malignant progression and poor survival for patients with glioma. Expression of TMEM44-AS1 increased the proliferation, colony formation, migration, and invasion of glioma cells. Knockdown of TMEM44-AS1 in glioma cells reduced cell proliferation, colony formation, migration and invasion, and tumor growth in a nude mouse xenograft model. Mechanistically, TMEM44-AS1 is directly bound to the SerpinB3, and sequentially activated Myc and EGR1/IL-6 signaling; Myc transcriptionally induced TMEM44-AS1 and directly bound to the promoter and super-enhancer of TMEM44-AS1, thus forming a positive feedback loop with TMEM44-AS. Further studies demonstrated that Myc interacts with MED1 regulates the super-enhancer of TMEM44-AS1. More importantly, a novel small-molecule Myc inhibitor, Myci975, alleviated TMEM44-AS1-promoted the growth of glioma cells.

Conclusions

Our study implicates a crucial role of the TMEM44-AS1-Myc axis in glioma progression and provides a possible anti-glioma therapeutic agent.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02129-9.

Upregulation of Serine Proteinase Inhibitor Clade B Member 3 (SERPINB3) Expression by Stromal Cell-Derived Factor (SDF-1)/CXCR4/Nuclear Factor kappa B (NF-κB) Promotes Migration and Invasion of Gastric Cancer Cells

BACKGROUND Serine proteinase inhibitor clade B member 3 (SERPINB3) is a neutral glycoprotein. Its overexpression is related to the promotion of cell proliferation and activation via the nuclear factor kappa B (NF-kappaB) pathway in several tumors. Whether it can participate in stromal cell-derived factor (SDF-1)/NF-kappaB-induced metastasis of gastric cancer has not been reported. MATERIAL AND METHODS We analyzed the ability of SDF-1 to induce migration and invasion in vitro by knocking down the expression of SERPINB3 with siRNAs in gastric cancer cells. We also explored the effects of a CXCR4 antagonist and NF-kappaB inhibitor on SERPINB3 expression. We verified the effect of SERPINB3 on prognosis in gastric cancer specimens by immunohistochemistry. RESULTS In vitro experiments confirmed that SDF-1 upregulated the expression of SERPINB3 and promoted metastasis in gastric cancer cells. This phenomenon was reversed by knockdown of SERPINB3, a chemokine receptor 4 (CXCR4) antagonist, and an NF-kappaB inhibitor, which downregulated the expression of SERPINB3. In patients with gastric cancer, a significant positive correlation was observed between CXCR4 and SERPINB3 expression (r=0.222, P=0.029). Moreover, double positivity for SERPINB3 and CXCR4 was certified to be an independent prognostic factor (HR=3.332, P<0.001). CXCR4-positive patients who also expressed SERPINB3 were inclined to suffer from lymph node metastasis, confirming that SERPINB3 is a downstream molecule of CXCR4. CONCLUSIONS In vitro and pathological results showed that SDF-1/CXCR4 activated the NF-kappaB pathway and upregulated SERPINB3 to facilitate the migration and invasion of gastric cancer cells.

Cancer classification of single-cell gene expression data by neural network

MOTIVATION

Cancer classification based on gene expression profiles has provided insight on the causes of cancer and cancer treatment. Recently, machine learning-based approaches have been attempted in downstream cancer analysis to address the large differences in gene expression values, as determined by single-cell RNA sequencing (scRNA-seq).

RESULTS

We designed cancer classifiers that can identify 21 types of cancers and normal tissues based on bulk RNA-seq as well as scRNA-seq data. Training was performed with 7398 cancer samples and 640 normal samples from 21 tumors and normal tissues in TCGA based on the 300 most significant genes expressed in each cancer. Then, we compared neural network (NN), support vector machine (SVM), k-nearest neighbors (kNN) and random forest (RF) methods. The NN performed consistently better than other methods. We further applied our approach to scRNA-seq transformed by kNN smoothing and found that our model successfully classified cancer types and normal samples.

AVAILABILITY AND IMPLEMENTATION

Cancer classification by neural network.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Autophagy Is Deficient and May be Negatively Regulated by SERPINB3 in Middle Ear Cholesteatoma

HYPOTHESIS

Whereas autophagy has been linked to various human diseases, whether it also plays a role in cholesteatoma is virtually unknown. This study aimed to investigate the activity and regulation of autophagy in cholesteatoma.

BACKGROUND

The treatment of middle ear cholesteatoma has been challenging due to an insufficient understanding of the underlying disease mechanism.

METHODS

Expression of microtubule-associated protein 1A/1B-light chain 3 (LC3), the autophagy protein marker, and phosphorylated Akt (p-Akt), and mammalian target of rapamycin (p-mTOR), the known autophagy regulators, in fresh retroauricular skin and cholesteatoma tissue samples was analyzed by immunoblotting. The results were further confirmed by immunohistochemistry and statistical analyses. Cell proliferation of primary retroauricular skin- and cholesteatoma-derived fibroblasts was evaluated by methyl thiazol tetrazolium (MTT) assay. Ectopic expression of serine proteinase inhibitor, clade B, member 3 (SERPINB3) in the fibroblasts was achieved by electroporation and the expression was detected by immunoblotting.

RESULTS

LC3 expression was significantly decreased in cholesteatoma in most of the 15 paired retroauricular skin/cholesteatoma tissue samples. However, p-Akt and p-mTOR expression in the cholesteatoma samples was not significantly different from that in the control subjects. Immunohistochemical studies further demonstrated an inverse correlation between LC3 expression and cholesteatoma. The cholesteatoma fibroblasts proliferated faster than the retroauricular skin fibroblasts, and had higher SERPINB3 but lower LC3 expression. Furthermore, overexpression of SERPINB3 in the retroauricular skin fibroblasts enhanced cell proliferation and downregulated LC3 expression.

CONCLUSION

Autophagy is significantly suppressed in cholesteatoma tissues, which may not involve the Akt/mTOR signaling pathway. More importantly, SERPINB3 may promote cell proliferation and negatively regulate autophagy in cholesteatoma fibroblasts. Together, these findings warrant further investigation into the pathogenic mechanism of cholesteatoma.

Enhanced expression of HNF4α during intestinal epithelial differentiation is involved in the activation of ER stress

Intestinal epithelial cells are derived from stem cells at the crypts that undergo differentiation into transit-amplifying cells, which in turn form terminally differentiated enterocytes as these cells reach the villus. Extensive alterations in both transcriptional and translational programs occur during differentiation, which can induce the activation of cellular stress responses such as ER stress-related unfolded protein response (UPR) and autophagy, particularly in the cells that are already committed to becoming absorptive cells. Using an epithelial cell model of enterocyte differentiation, we report a mechanistic study connecting enterocyte differentiation to UPR and autophagy. We report that differentiated colon epithelial cells showed increased cytosolic Ca²⁺ levels and activation of all three pathways of UPR: inositol-requiring enzyme 1 (IRE1), protein kinase RNA-like ER kinase, and activating transcription factor 6 (ATF6) compared to the undifferentiated cells. Enhanced UPR in the differentiated cells was accompanied by the induction of autophagy as evidenced by increased ratio of light chain 3 II/I, upregulation of Beclin-1, and downregulation of p62. We show for the first time that mechanistically, the upregulation of hepatocyte nuclear factor 4α (HNF4α) during differentiation led to increased promoter binding and transcriptional upregulation of two major proteins of UPR: X-box binding protein-1 and ATF6, implicating HNF4α as a key regulator of UPR response during differentiation. Integrating wet-lab with in silico analyses, the present study links differentiation to cellular stress responses, and highlights the importance of transcription factor signaling and cross-talk between the cellular events in the regulation of intestinal cell differentiation.

SerpinB3 Differently Up-Regulates Hypoxia Inducible Factors -1α and -2α in Hepatocellular Carcinoma: Mechanisms Revealing Novel Potential Therapeutic Targets

SerpinB3 (SB3) is a hypoxia and hypoxia-inducible factor (HIF)-2α-dependent cysteine-protease inhibitor up-regulated in hepatocellular carcinoma (HCC), released by cancer cells and able to stimulate proliferation and epithelial-to-mesenchymal-transition. Methods: In the study we employed transgenic and knock out SerpinB3 mice, liver cancer cell line, human HCC specimens, and mice receiving diethyl-nitrosamine (DEN) administration plus choline-deficient L-amino acid refined (CDAA) diet (DEN/CDAA protocol). Results: We provide detailed and mechanistic evidence that SB3 can act as a paracrine mediator able to affect the behavior of surrounding cells by differentially up-regulating, in normoxic conditions, HIF-1α and HIF-2α. SB3 acts by (i) up-regulating HIF-1α transcription, facilitating cell survival in a harsh microenvironment and promoting angiogenesis, (ii) increasing HIF-2α stabilization via direct/selective NEDDylation, promoting proliferation of liver cancer cells, and favoring HCC progression. Moreover (iii) the highest levels of NEDD8-E1 activating enzyme (NAE1) mRNA were detected in a subclass of HCC patients expressing the highest levels of HIF-2α transcripts; (iv) mice undergoing DEN/CDAA carcinogenic protocol showed a positive correlation between SB3 and HIF-2α transcripts with the highest levels of NAE1 mRNA detected in nodules expressing the highest levels of HIF-2α transcripts. Conclusions: These data outline either HIF-2α and NEDDylation as two novel putative therapeutic targets to interfere with the procarcinogenic role of SerpinB3 in the development of HCC.

M2-polarized tumor-associated macrophages promote epithelial-mesenchymal transition via activation of the AKT3/PRAS40 signaling pathway in intrahepatic cholangiocarcinoma

Tumor-associated macrophages (TAMs) have been considered as a major component of the tumor microenvironment. However, the crosstalk between M2-polarized tumor-associated macrophages (M2-TAMs) and intrahepatic cholangiocarcinoma (ICC) remains undetermined. In the present study, we aimed to clarify the role of M2-TAMs in ICC and the underlying mechanism. The in vitro assay demonstrated M2-TAMs promoted epithelial-mesenchymal transition (EMT) of ICC cells, resulting in enhanced cell invasion and metastasis ability. Moreover, M2-TAMs modulated the microenvironment of ICC by increasing the secretion of cytokines (GM-CSF, tumor necrosis factor-α [TNF-α], ICAM-1, interleukin-6 [IL-6], etc) and chemokines (CCL1, CCL3, etc). In addition, p-AKT (Ser473) and p-PRAS40 (Thr246) were upregulated in ICC cells when cocultured with M2-TAMs or treated with M2-TAMs secreted core cytokines (GM-CSF, TNF-α, ICAM-1, and IL-6). Consistently, AKT3 silencing (but not AKT1 silencing and AKT2 silencing) markedly inhibited phosphorylation of AKT and PRAS40 of ICC cells and inhibited the EMT process when cocultured with M2-TAMs. Taken together, the current data indicated that M2-TAMs promoted ICC cells EMT, partially through increasing secretion of cytokines and chemokines, thus modulating the microenvironment and activating the AKT3/PRAS40 signaling pathway.

Impact and Relevance of the Unfolded Protein Response in HNSCC

Head and neck squamous cell carcinomas (HNSCC) encompass a heterogeneous group of solid tumors that arise from the upper aerodigestive tract. The tumor cells face multiple challenges including an acute demand of protein synthesis often driven by oncogene activation, limited nutrient and oxygen supply and exposure to chemo/radiotherapy, which forces them to develop adaptive mechanisms such as the Unfolded Protein Response (UPR). It is now well documented that the UPR, a homeostatic mechanism, is induced at different stages of cancer progression in response to intrinsic (oncogenic activation) or extrinsic (microenvironment) perturbations. This review will discuss the role of the UPR in HNSCC as well as in the key processes that characterize the physiology of HNSCC. The role of the UPR in the clinical context of HNSCC will also be addressed.

UPR: An Upstream Signal to EMT Induction in Cancer

The endoplasmic reticulum (ER) is the organelle where newly synthesized proteins enter the secretory pathway. Different physiological and pathological conditions may perturb the secretory capacity of cells and lead to the accumulation of misfolded and unfolded proteins. To relieve the produced stress, cells evoke an adaptive signalling network, the unfolded protein response (UPR), aimed at recovering protein homeostasis. Tumour cells must confront intrinsic and extrinsic pressures during cancer progression that produce a proteostasis imbalance and ER stress. To overcome this situation, tumour cells activate the UPR as a pro-survival mechanism. UPR activation has been documented in most types of human tumours and accumulating evidence supports a crucial role for UPR in the establishment, progression, metastasis and chemoresistance of tumours as well as its involvement in the acquisition of other hallmarks of cancer. In this review, we will analyse the role of UPR in cancer development highlighting the ability of tumours to exploit UPR signalling to promote epithelial-mesenchymal transition (EMT).

Serum SCCA levels in patients suffering cancers or other diseases

Increased serum squamous cell carcinoma antigen (SCCA) levels are clinically used diagnostic or prognostic biomarker for squamous cell carcinomas. According to recently published studies, increased serum SCCA levels are also observed in adenocarcinomas, hepatocarcinomas, kidney, and other inflammatory diseases, indicating squamous cell carcinoma is not the production source of serum SCCA in these diseases. However, serum SCCA levels in patients suffering different types of diseases have not been systematically measured and compared. Thus, in our current study, serum SCCA levels from 21,608 patients with 39 clinically defined diseases were collected and measured by the clinical laboratory in the Affiliated Hospital of Qingdao University over the past 5 years in addition to 232 serum samples from individuals who attend their annual physical examination as the healthy controls. According to the median, mean, and -log₁₀p values, we found that patients with uremia, azotemia, diabetic nephropathy, and nephritic syndrome had the highest serum SCCA levels among all 39 different types of diseases including patients suffering squamous cell carcinomas. Moreover, patients suffering lung cancer, cervical cancer, esophagus cancer, or chronic pulmonary disease had lower median and interquartile range values but higher or comparable mean values and significantly higher SD values than that of the healthy controls. Furthermore, patients with endometrial cancer, pancreatitis, osteoporosis, and some other diseases had lower serum SCCA levels than that of the healthy controls. These results demonstrated that serum SCCA can not only be used in diagnosis and prognosis of squamous cell carcinomas but also as biomarkers for uremia, azotemia, diabetic nephropathy, and nephritic syndrome.

Human cardiac progenitor cell activation and regeneration mechanisms: exploring a novel myocardial ischemia/reperfusion in vitro model

BACKGROUND

Numerous studies from different labs around the world report human cardiac progenitor cells (hCPCs) as having a role in myocardial repair upon ischemia/reperfusion (I/R) injury, mainly through auto/paracrine signaling. Even though these cell populations are already being investigated in cell transplantation-based clinical trials, the mechanisms underlying their response are still poorly understood.

METHODS

To further investigate hCPC regenerative process, we established the first in vitro human heterotypic model of myocardial I/R injury using hCPCs and human-induced pluripotent cell-derived cardiomyocytes (hiPSC-CMs). The co-culture model was established using transwell inserts and evaluated in both ischemia and reperfusion phases regarding secretion of key cytokines, hiPSC-CM viability, and hCPC proliferation. hCPC proteome in response to I/R was further characterized using advanced liquid chromatography mass spectrometry tools.

RESULTS

This model recapitulates hallmarks of I/R, namely hiPSC-CM death upon insult, protective effect of hCPCs on hiPSC-CM viability (37.6% higher vs hiPSC-CM mono-culture), and hCPC proliferation (approximately threefold increase vs hCPCs mono-culture), emphasizing the importance of paracrine communication between these two populations. In particular, in co-culture supernatant upon injury, we report higher angiogenic functionality as well as a significant increase in the CXCL6 secretion rate, suggesting an important role of this chemokine in myocardial regeneration. hCPC whole proteome analysis allowed us to propose new pathways in the hCPC-mediated regenerative process, including cell cycle regulation, proliferation through EGF signaling, and reactive oxygen species detoxification.

CONCLUSION

This work contributes with new insights into hCPC biology in response to I/R, and the model established constitutes an important tool to study the molecular mechanisms involved in the myocardial regenerative process.

The Role of the ER-Induced UPR Pathway and the Efficacy of Its Inhibitors and Inducers in the Inhibition of Tumor Progression

Cancer is the second most frequent cause of death worldwide. It is considered to be one of the most dangerous diseases, and there is still no effective treatment for many types of cancer. Since cancerous cells have a high proliferation rate, it is pivotal for their proper functioning to have the well-functioning protein machinery. Correct protein processing and folding are crucial to maintain tumor homeostasis. Endoplasmic reticulum (ER) stress is one of the leading factors that cause disturbances in these processes. It is induced by impaired function of the ER and accumulation of unfolded proteins. Induction of ER stress affects many molecular pathways that cause the unfolded protein response (UPR). This is the way in which cells can adapt to the new conditions, but when ER stress cannot be resolved, the UPR induces cell death. The molecular mechanisms of this double-edged sword process are involved in the transition of the UPR either in a cell protection mechanism or in apoptosis. However, this process remains poorly understood but seems to be crucial in the treatment of many diseases that are related to ER stress. Hence, understanding the ER stress response, especially in the aspect of pathological consequences of UPR, has the potential to allow us to develop novel therapies and new diagnostic and prognostic markers for cancer.

Early Stage Alterations in CA1 Extracellular Region Proteins Indicate Dysregulation of IL6 and Iron Homeostasis in the 5XFAD Alzheimer's Disease Mouse Model

In recent years, an increasing number of research papers revealed that the compositional and volumetric alterations in the extracellular matrix are the consequences of aging and may be related to Alzheimer's disease (AD). In this study, we aimed to demonstrate the alterations in hippocampal extracellular fluid proteins in vivo using the 5XFAD mouse model. Samples were obtained from hippocampi of 5XFAD mice (n = 6) and their non-transgenic littermates by intracerebral push-pull perfusion technique at 3 months of age, representing the pre-pathological stage of the AD. Proteins in the hippocampal perfusates were analyzed by Ultra Performance Liquid Chromatography-Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry (UPLC-ESI-qTOF-MS/MS). 178 proteins were identified and 19 proteins of them were found to be statistically significantly altered (p≤0.05, fold change ≥40%, unique peptide count ≥3) in the hippocampal CA1 extracellular fluid of the 5XFAD mouse model. Ingenuity pathway analysis of the protein expression results identified IL6 as an upstream regulator. The upregulation of IL6 was validated by immunohistochemical staining of the hippocampus and cortex of the 5XFAD mice prior to Aβ plaque formation. Furthermore, the iron level in the hippocampus was measured by inductively coupled plasma-mass spectrometry as IL6 is mentioned in several studies to take part in iron homeostasis and inflammation and found to be increased in 5XFAD mice hippocampus. Alterations in extracellular matrix proteins in addition to increasing amount of hippocampal IL6 and iron in the early stages of AD may reveal inflammation-mediated iron dyshomeostasis in the early stages of neurodegeneration.

Assessment of cellular and serum proteome from tongue squamous cell carcinoma patient lacking addictive proclivities for tobacco, betel nut, and alcohol: Case study

The intriguing molecular pathways involved in oral carcinogenesis are still ambiguous. The oral squamous cell carcinoma (OSCC) ranks as the most common type constituting more than 90% of the globally diagnosed oral cancers cases. The elevation in the OSCC incidence rate during past 10 years has an alarming impression on human healthcare. The major challenges associated with OSCC include delayed diagnosis, high metastatic rates, and low 5-year survival rates. The present work foundations on reverse genetic strategy and involves the identification of genes showing expressional variability in an OSCC case lacking addictive proclivities for tobacco, betel nut, and/or alcohol, major etiologies. The expression modulations in the identified genes were analyzed in 16 patients comprising oral pre-cancer and cancer histo-pathologies. The genes SCCA1 and KRT1 were found to down regulate while DNAJC13, GIPC2, MRPL17, IG-Vreg, SSFA2, and UPF0415 upregulated in the oral pre-cancer and cancer pathologies, implicating the genes as crucial players in oral carcinogenesis.

Proteome-wide analysis of protein abundance and turnover remodelling during oncogenic transformation of human breast epithelial cells

Background: Viral oncogenes and mutated proto-oncogenes are potent drivers of cancer malignancy. Downstream of the oncogenic trigger are alterations in protein properties that give rise to cellular transformation and the acquisition of malignant cellular phenotypes. Developments in mass spectrometry enable large-scale, multidimensional characterisation of proteomes. Such techniques could provide an unprecedented, unbiased view of how oncogene activation remodels a human cell proteome. Methods: Using quantitative MS-based proteomics and cellular assays, we analysed how transformation induced by activating v-Src kinase remodels the proteome and cellular phenotypes of breast epithelial (MCF10A) cells. SILAC MS was used to comprehensively characterise the MCF10A proteome and to measure v-Src-induced changes in protein abundance across seven time-points (1-72 hrs). We used pulse-SILAC MS ( Boisvert et al., 2012), to compare protein synthesis and turnover in control and transformed cells. Follow-on experiments employed a combination of cellular and functional assays to characterise the roles of selected Src-responsive proteins. Results: Src-induced transformation changed the expression and/or turnover levels of ~3% of proteins, affecting ~1.5% of the total protein molecules in the cell. Transformation increased the average rate of proteome turnover and disrupted protein homeostasis. We identify distinct classes of protein kinetics in response to Src activation. We demonstrate that members of the polycomb repressive complex 1 (PRC1) are important regulators of invasion and migration in MCF10A cells. Many Src-regulated proteins are present in low abundance and some are regulated post-transcriptionally. The signature of Src-responsive proteins is highly predictive of poor patient survival across multiple cancer types. Open access to search and interactively explore all these proteomic data is provided via the EPD database ( www.peptracker.com/epd). Conclusions: We present the first comprehensive analysis measuring how protein expression and protein turnover is affected by cell transformation, providing a detailed picture at the protein level of the consequences of activation of an oncogene.

A shift from papillary to reticular fibroblasts enables tumour-stroma interaction and invasion

Background

Tumour stroma consists of a heterogeneous population of fibroblasts and related mesenchymal cells, collectively dubbed cancer-associated fibroblasts (CAFs). These CAFs are key players in cancer invasion of cutaneous squamous cell carcinoma (SCC). As we have shown earlier, papillary and reticular fibroblasts (Pfs and Rfs, respectively) have distinct effects on epidermal and dermal homeostasis, but their role in cancer invasion and epithelial-to-mesenchymal transition (EMT) remains to be determined.

Methods

We used 3D cultures of human skin equivalents (HSEs) to analyse the effects of Pfs and Rfs on the invasive behaviour of SCC and EMT.

Results

We reveal for the first time the importance of Pfs versus Rfs in SCC invasion and EMT. Cell lines from different stages of SCC showed significantly more extensive invasion into a dermis composed of Rfs than of Pfs. In addition, Rfs-based HSEs showed increased cell activation and stained positive for CAF biomarkers α-SMA and vimentin. Further analysis revealed that invasively growing cancer cells in Rf-HSEs express markers of EMT transition, like SNAIL2, N-cadherin and ZEB1.

Conclusions

Conversely, our results show that Pfs contain cancer cells more within the epidermis. Rfs are clearly predisposed to differentiate into CAFs upon SCC signals, assisting invasion and EMT.

Serpinb3 is overexpressed in the liver in presence of iron overload

Iron overload results in cellular toxicity, tissue injury, organ fibrosis and increased risk of neoplastic transformation. SerpinB3 is a serine protease inhibitor overexpressed in the liver in oxidative stress conditions, able to induce fibrosis and increased risk of malignant transformation. Aim of the present study was to assess the effect of iron overload on SerpinB3 expression in the liver using in vivo and in vitro models.The expression of Serpinb3 was assessed in the liver of hemojuvelin knockout mice (Hjv-/-), an established model of hereditary hemochromatosis, and of wild type control mice, following dietary or pharmacological iron manipulation. To assess the direct effect of iron in vitro, cell lines were treated with different concentration of hemin or with an iron chelator.Hepatic Serpinb3 mRNA and protein were highly expressed in Hjv-/- mice, but not in wild type controls fed with a standard diet. Serpinb3 became detectable in wild type mice fed with a high iron diet or injected with iron dextran; these treatments further induced Serpinb3 expression in Hjv-/- mice. Livers expressing Serpinb3 showed a positive staining also for HIF-2α in the same areas. Hemin promoted induction of SerpinB3 mRNA in HeLa and HA22T/VGH cells, but a mild stimulation of SerpinB3 promoter activity in HeLa and Huh7 cells. In conclusion, Serpinb3 is strongly induced by iron in the mouse liver. The molecular link between iron, ROS and SerpinB3 seems to be HIF-2α, which is induced by iron overload and was previously found capable of up-regulating SerpinB3 at the transcriptional level.

Endoplasmic reticulum stress signaling and chemotherapy resistance in solid cancers

The unfolded protein response (UPR) is an adaptive cellular program used by eukaryotic cells to cope with protein misfolding stress. During tumor development, cancer cells are facing intrinsic (oncogene activation) and extrinsic (limiting nutrient or oxygen supply) challenges, with which they must cope to survive. Moreover, chemotherapy represents an additional extrinsic challenge that cancer cells are facing and to which they adapt in the case of resistance. As of today, resistance to chemotherapy and targeted therapies is one of the important issues that oncologists have to deal with for treating cancer patients. In this review, we first describe the key molecular mechanisms controlling the UPR and their implication in solid cancers. Then, we review the literature that connects cancer chemotherapy resistance mechanisms and activation of the UPR. Finally, we discuss the possible applications of targeting the UPR to bypass drug resistance.

SerpinB3 upregulates the Cyclooxygenase-2 / β-Catenin positive loop in colorectal cancer

Colorectal cancer is characterized by aberrant Cyclooxigenase-2 (COX-2) and β-Catenin pathways. Recently, the protease inhibitor SerpinB3 has been described overexpressed in more advanced stages of this tumor. Aim of the study was to explore the possible relationship between these molecules in this setting. We evaluated colorectal cancer specimens from 105 patients and a positive correlation between SerpinB3, COX-2 and β-Catenin expression was observed, with higher levels in tumor than in adjacent tissue. The highest levels were associated with pathologic parameters of poor prognosis, including vascular invasion, lymph node metastasis and perineural invasion. The molecular and protein profiles of COX-2 and β-Catenin were analyzed in cell lines with different expression of SerpinB3. In those with high expression of SerpinB3, COX-2 and β-Catenin were higher than in controls. Cells with high levels of SerpinB3 showed higher proliferation and invasion compared to controls. In conclusion, in colorectal cancer SerpinB3, COX-2 and β-Catenin are positively correlated and associated with more advanced tumor stage. The in vitro experimental results support a driving role of SerpinB3 in the upregulation of COX-2/ β-Catenin positive loop, associated with a more aggressive cellular phenotype.

Driving Cancer Tumorigenesis and Metastasis Through UPR Signaling

In the tumor microenvironment, cancer cells encounter both external and internal factors that can lead to the accumulation of improperly folded proteins in the Endoplasmic Reticulum (ER) lumen, thus causing ER stress. When this happens, an adaptive mechanism named the Unfolded Protein Response (UPR) is triggered to help the cell cope with this change and restore protein homeostasis in the ER. Sequentially, one would expect that the activation of the three UPR branches, driven namely by IRE1, PERK, and ATF6, are crucial for the adaptation of cancer cells to the changing environment and thus for their survival and further propagation. Indeed, in the last few years, an increasing amount of studies has shown the implication of UPR signaling in different aspects of carcinogenesis and tumor progression. Features such as sustaining proliferation and resistance to cell death, genomic instability, altered metabolism, increased inflammation and tumor-immune infiltration, invasion and metastasis, and angiogenesis, defined as "the hallmarks of cancer", can be regulated by the UPR machinery. At the same time, new potential therapeutic interventions applicable to different kinds of cancers are being revealed. In order to describe the emerging role of UPR in cancer biology, these are the points that will be discussed in this chapter.

Endoplasmic reticulum proteostasis: a key checkpoint in cancer

The unfolded protein response (UPR) is an intracellular signaling network largely controlled by three endoplasmic reticulum (ER) transmembrane proteins, inositol-requiring enzyme 1α, PRK-like ER kinase, and activating transcription factor 6, that monitor the protein-folding status of the ER and initiate corrective measures to maintain ER homeostasis. Hypoxia, nutrient deprivation, proteasome dysfunction, sustained demands on the secretory pathway or somatic mutations in its client proteins, conditions often encountered by cancer cells, can lead to the accumulation of misfolded proteins in the ER and cause "ER stress." Under remediable levels of ER stress, the homeostatic UPR outputs activate transcriptional and translational changes that promote cellular adaptation. However, if the ER stress is irreversible despite these measures, a terminal UPR program supersedes that actively signals cell destruction. In addition to its prosurvival and prodeath outputs, the UPR is now recognized to play a major role in the differentiation and activation of specific immune cells, as well as proinflammatory cytokine production in many cell types. Given the numerous intrinsic and extrinsic factors that threaten the fidelity of the secretory pathway in cancer cells, it is not surprising that ER stress is documented in many solid and hematopoietic malignancies, but whether ongoing UPR signaling is beneficial or detrimental to tumor growth remains hotly debated. Here I review recent evidence that cancer cells are prone to loss of proteostasis within the ER, and hence may be susceptible to targeted interventions that either reduce homeostatic UPR outputs or alternatively trigger the terminal UPR.

HRD1 suppresses the growth and metastasis of breast cancer cells by promoting IGF-1R degradation

HRD1 (3-hydroxy-3-methylglutaryl reductase degradation) is an E3 ubiquitin ligase. We found that HRD1 was significantly downregulated in 170 breast cancer tissues. Low tumoral HRD1 expression was correlated with clinicopathological characteristics and a shorter survival in breast cancer patients. P65 specifically bound to the HRD1 promoter and inhibited HRD1 expression. Suppression of NF-κB activity reversed IL-6-induced downregulation of HRD1 expression. HRD1 interacted with IGF-1R and promoted its ubiquitination and degradation by the proteasome. Overexpression of HRD1 resulted in the inhibition of growth, migration and invasion of breast cancer cells in vitro and in vivo. Furthermore, HRD1 attenuated IL-6-induced epithelial-mesenchymal transition in MCF10A cells. These findings uncover a novel role for HRD1 in breast cancer.

SERPINB3 and B4: From biochemistry to biology

Human SERPINB3 and SERPINB4 are evolutionary duplicated serine/cysteine protease inhibitors. Genomic analysis indicates that these paralogous genes were encoded from independent loci arising from tandem gene duplication. Although the two molecules share 92% identity of their amino acid sequences, they are distinct in the Reactive Center Loop (RCL) including a hinge region and catalytic sequences which accounts for altered substrate specificity. Elevated expression of the two molecules has been reported to contribute to numerous pathological conditions such as inflammatory diseases and cancer. In this review, we focus on summarizing the biochemical features of SERPINB3/B4 and discussing the mechanistic basis for their biological functions and implications in human diseases.

Reprint of: Signaling the Unfolded Protein Response in primary brain cancers

The Unfolded Protein Response (UPR) is an adaptive cellular program used by eukaryotic cells to cope with protein misfolding stress in the Endoplasmic Reticulum (ER). During tumor development, cancer cells are facing intrinsic (oncogene activation) and extrinsic (limiting nutrient or oxygen supply; exposure to chemotherapies) challenges, with which they must cope to survive. Primary brain tumors are relatively rare but deadly and present a significant challenge in the determination of risk factors in the population. These tumors are inherently difficult to cure because of their protected location in the brain. As such surgery, radiation and chemotherapy options carry potentially lasting patient morbidity and incomplete tumor cure. Some of these tumors, such as glioblastoma, were reported to present features of ER stress and to depend on UPR activation to sustain growth, but to date there is no clear general representation of the ER stress status in primary brain tumors. In this review, we describe the key molecular mechanisms controlling the UPR and their implication in cancers. Then we extensively review the literature reporting the status of ER stress in various primary brain tumors and discuss the potential impact of such observation on patient stratification and on the possibility of developing appropriate targeted therapies using the UPR as therapeutic target. This article is part of a Special Issue entitled SI:ER stress.

RNA sequencing-based analysis of gallbladder cancer reveals the importance of the liver X receptor and lipid metabolism in gallbladder cancer

Gallbladder cancer (GBC) is an aggressive malignancy. Although surgical resection may be curable, most patients are diagnosed at an advanced unresectable disease stage. Cholelithiasis is the major risk factor; however the pathogenesis of the disease, from gallstone cholecystitis to cancer, is still not understood. To understand the molecular genetic underpinnings of this cancer and explore novel therapeutic targets for GBC, we examined the key genes and pathways involved in GBC using RNA sequencing. We performed gene expression analysis of 32 cases of surgically-resected GBC along with normal gallbladder tissue controls. We observed that 519 genes were differentially expressed between GBC and normal GB mucosal controls. The liver X receptor (LXR)/retinoid X receptor (RXR) and farnesoid X receptor (FXR) /RXR pathways were the top canonical pathways involved in GBC. Key genes in these pathways, including SERPINB3 and KLK1, were overexpressed in GBC, especially in female GBC patients. Additionally, ApoA1 gene expression suppressed in GBC as compared with normal control tissues. LXR and FXR genes, known to be important in lipid metabolism also function as tumor suppressors and their down regulation appears to be critical for GBC pathogenesis. LXR agonists may have therapeutic value and as potential therapeutic targets.

Endoplasmic Reticulum Stress and the Hallmarks of Cancer

Tumor cells are often exposed to intrinsic and external factors that alter protein homeostasis, thus producing endoplasmic reticulum (ER) stress. To cope with this, cells evoke an adaptive mechanism to restore ER proteostasis known as the unfolded protein response (UPR). The three main UPR signaling branches initiated by IRE1α, PERK, and ATF6 are crucial for tumor growth and aggressiveness as well as for microenvironment remodeling or resistance to treatment. We provide a comprehensive overview of the contribution of the UPR to cancer biology and the acquisition of malignant characteristics, thus highlighting novel aspects including inflammation, invasion and metastasis, genome instability, resistance to chemo/radiotherapy, and angiogenesis. The therapeutic potential of targeting ER stress signaling in cancer is also discussed.

Preoperative SCC Antigen, CRP Serum Levels, and Lymph Node Density in Oral Squamous Cell Carcinoma

The prognostic significance of squamous cell carcinoma antigen (SCC-Ag) and C-reactive protein (CRP) levels and lymph node density (LND) has been individually recognized in oral squamous cell carcinoma (OSCC). We investigated the relationship between preoperative serum markers (SCC-Ag and CRP) and postoperative prognostic marker (LND) in this study. We retrospectively analyzed 277 OSCC patients who underwent primary curative resection and neck dissection with/or without adjuvant therapy between March 2008 and November 2013. Serum SCC-Ag and CRP levels were measured preoperatively. Distant metastasis, overall survival (OS), and disease-free survival (DFS) were used to evaluate the prognostic significance of preoperative SCC-Ag and CRP levels in relation to LND. LND (cutoff point ≥0.06) correlated with the pathologic tumor status, pathologic nodal metastasis, degree of differentiation, tumor stage, tumor depth (≥10 mm vs <10 mm), and perineural invasion (all P values were <0.001). LND was significantly associated with development of distant metastasis, DFS, and OS (all P values were <0.001). Preoperative elevated CRP and SCC-Ag levels were significantly associated with LND (P = 0.006), DFS (P < 0.001), and OS (P < 0.001). LND patients were further stratified into prognostic groups according to their SCC-Ag and CRP levels (DFS: P = 0.010; OS: P = 0.003). LND correlated with the incidence of DM, DFS, and OS in patients with OSCC. Concurrent elevated preoperative SCC-Ag and CRP levels are predictors for LND. In addition, SCC-Ag and CRP are markers for classifying high-risk LND patients with OSCC into subgroups.

Signaling the Unfolded Protein Response in primary brain cancers

The Unfolded Protein Response (UPR) is an adaptive cellular program used by eukaryotic cells to cope with protein misfolding stress in the Endoplasmic Reticulum (ER). During tumor development, cancer cells are facing intrinsic (oncogene activation) and extrinsic (limiting nutrient or oxygen supply; exposure to chemotherapies) challenges, with which they must cope to survive. Primary brain tumors are relatively rare but deadly and present a significant challenge in the determination of risk factors in the population. These tumors are inherently difficult to cure because of their protected location in the brain. As such surgery, radiation and chemotherapy options carry potentially lasting patient morbidity and incomplete tumor cure. Some of these tumors, such as glioblastoma, were reported to present features of ER stress and to depend on UPR activation to sustain growth, but to date there is no clear general representation of the ER stress status in primary brain tumors. In this review, we describe the key molecular mechanisms controlling the UPR and their implication in cancers. Then we extensively review the literature reporting the status of ER stress in various primary brain tumors and discuss the potential impact of such observation on patient stratification and on the possibility of developing appropriate targeted therapies using the UPR as therapeutic target.

Cancer development, chemoresistance, epithelial to mesenchymal transition and stem cells: A snapshot of IL-6 mediated involvement

Interleukin-6 (IL-6) is a cytokine present in tumor microenvironment. Elevated level of IL-6 is associated with cancer cell proliferation, angiogenesis and metastasis through fueling STAT3, MAPK and Akt signaling. It promotes epithelial to mesenchymal transition (EMT) through altered expression of N-cadherin, vimentin, snail, twist and E-cadherin leading to cancer metastasis. IL-6 boosts mammosphere formation, self-renewal of stem cells, stemness properties of cancer cells and recruitment of mesenchymal stem cells. IL-6 is also a contributing factor for multidrug resistance in cancer due to gp130/MAPK/STAT3 mediated activation of transcription factors C/EBPβ/δ, overexpression of p-glycoprotein, EMT transition and expansion of stem cells. The in-depth investigation of IL-6 mediated cellular effects and its signaling pathway can provide the new window for future research and clinical development of IL-6 targeted therapy in cancer. Thus, an overview is delivered in this review deciphering the emerging aspect of the predominant influence of IL-6 in malignant transformation, EMT, cancer-associated stem cells and chemoresistance.

Squamous cell carcinoma antigen-IgM is associated with hepatocellular carcinoma in patients with cirrhosis: A prospective study

BACKGROUND

Squamous cell carcinoma antigen (SCCA)-IgM complex has been described as a promising tool to identify patients with progressive liver disease at higher risk of hepatocellular carcinoma (HCC) development in retrospective studies.

AIM

To assess the clinical value of this biomarker in patients with cirrhosis in a prospective study.

METHODS

Patients with overt cirrhosis were prospectively evaluated at 6-month intervals for HCC development and decompensation with clinical examination, liver ultrasound, α-fetoprotein measurement. SCCA-IgM was measured in serum by immunoenzymatic assay. Median follow-up duration was 52 months (range 12-68 months).

RESULTS

70 patients (26% male; mean age 56±10 years) were enrolled. The main aetiological factors were alcohol (44%) and hepatitis C (34%). Baseline values of SCCA-IgM were significantly higher in patients who developed HCC. Positivity of the biomarker at baseline was associated with a significantly shorter HCC-free survival, while α-fetoprotein (cut off >20 ng/ml) was not significant. SCCA-IgM positivity and hepatitis C were significant prognostic factors for HCC development. The biomarker was not associated with the development of clinical complications of cirrhosis.

CONCLUSION

This prospective study demonstrates that in patients with cirrhosis SCCA-IgM is associated with HCC development and may be useful for clinical management of cirrhotic patients at higher risk of HCC development.

SerpinB3 and Yap Interplay Increases Myc Oncogenic Activity

SerpinB3 has been recently described as an early marker of liver carcinogenesis, but the potential mechanistic role of this serpin in tumor development is still poorly understood. Overexpression of Myc often correlates with more aggressive tumour forms, supporting its involvement in carcinogenesis. Yes-associated protein (Yap), the main effector of the Hippo pathway, is a central regulator of proliferation and it has been found up-regulated in hepatocellular carcinomas. The study has been designed to investigate and characterize the interplay and functional modulation of Myc by SerpinB3 in liver cancer. Results from this study indicate that Myc was up-regulated by SerpinB3 through calpain and Hippo-dependent molecular mechanisms in transgenic mice and hepatoma cells overexpressing human SerpinB3, and also in human hepatocellular carcinomas. Human recombinant SerpinB3 was capable to inhibit the activity of Calpain in vitro, likely reducing its ability to cleave Myc in its non oncogenic Myc-nick cytoplasmic form. SerpinB3 indirectly increased the transcription of Myc through the induction of Yap pathway. These findings provide for the first time evidence that SerpinB3 can improve the production of Myc through direct and indirect mechanisms that include the inhibition of generation of its cytoplasmic form and the activation of Yap pathway.