SERPINB3 protects from oxidative damage by chemotherapeutics through inhibition of mitochondrial respiratory complex I

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 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.

Therapeutic Efficiency of Proteins Secreted by Glial Progenitor Cells in a Rat Model of Traumatic Brain Injury

Traumatic brain injuries account for 30-50% of all physical traumas and are the most common pathological diseases of the brain. Mechanical damage of brain tissue leads to the disruption of the blood-brain barrier and the massive death of neuronal, glial, and endothelial cells. These events trigger a neuroinflammatory response and neurodegenerative processes locally and in distant parts of the brain and promote cognitive impairment. Effective instruments to restore neural tissue in traumatic brain injury are lacking. Glial cells are the main auxiliary cells of the nervous system, supporting homeostasis and ensuring the protection of neurons through contact and paracrine mechanisms. The glial cells' secretome may be considered as a means to support the regeneration of nervous tissue. Consequently, this study focused on the therapeutic efficiency of composite proteins with a molecular weight of 5-100 kDa secreted by glial progenitor cells in a rat model of traumatic brain injury. The characterization of proteins below 100 kDa secreted by glial progenitor cells was evaluated by proteomic analysis. Therapeutic effects were assessed by neurological outcomes, measurement of the damage volume by MRI, and an evaluation of the neurodegenerative, apoptotic, and inflammation markers in different areas of the brain. Intranasal infusions of the composite protein product facilitated the functional recovery of the experimental animals by decreasing the inflammation and apoptotic processes, preventing neurodegenerative processes by reducing the amounts of phosphorylated Tau isoforms Ser396 and Thr205. Consistently, our findings support the further consideration of glial secretomes for clinical use in TBI, notably in such aspects as dose-dependent effects and standardization.

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.

Bile detection of squamous cell carcinoma antigen (SCCA) in extrahepatic cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is a rare biliary tract tumor with poor prognosis that often is challenging to diagnose and the majority of patients present with advanced stage. Squamous cell carcinoma antigen 1 (SCCA1) overexpression has been found in different tumors associated with poor prognosis and chemoresistance.

AIMS

To assess the presence and possible prognostic role of SCCA1/2 isoforms in bile and serum of patients with CCA.

METHODS

Forty seven surgical patients (36 with CCA and 11 with benign diseases) were prospectively included in the study. Serum and bile specimens were collected at the time of surgery and free and IgM-complexed SCCA was quantified by ELISA (Xeptagen, srl).

RESULTS

Free or IgM linked SCCA was rarely found in serum, while SCCA was detectable in bile samples of patients with CCA, especially in those with extrahepatic form (43% vs 17%, p = 0.008), but not in controls. Despite similar tumor stage, these positive patients presented a trend toward a higher percentage of portal invasion (27% vs 15%) and of tumor recurrence than negative cases (62% vs 40%), although the difference was not statistically significant.

CONCLUSION

These preliminary results indicate that bile testing for SCCA is a specific marker of extrahepatic CCA, with potential prognostic value.

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.  

Tumor growth of neurofibromin-deficient cells is driven by decreased respiration and hampered by NAD+ and SIRT3

Neurofibromin loss drives neoplastic growth and a rewiring of mitochondrial metabolism. Here we report that neurofibromin ablation dampens expression and activity of NADH dehydrogenase, the respiratory chain complex I, in an ERK-dependent fashion, decreasing both respiration and intracellular NAD⁺. Expression of the alternative NADH dehydrogenase NDI1 raises NAD⁺/NADH ratio, enhances the activity of the NAD⁺-dependent deacetylase SIRT3 and interferes with tumorigenicity in neurofibromin-deficient cells. The antineoplastic effect of NDI1 is mimicked by administration of NAD⁺ precursors or by rising expression of the NAD⁺ deacetylase SIRT3 and is synergistic with ablation of the mitochondrial chaperone TRAP1, which augments succinate dehydrogenase activity further contributing to block pro-neoplastic metabolic changes. These findings shed light on bioenergetic adaptations of tumors lacking neurofibromin, linking complex I inhibition to mitochondrial NAD⁺/NADH unbalance and SIRT3 inhibition, as well as to down-regulation of succinate dehydrogenase. This metabolic rewiring could unveil attractive therapeutic targets for neoplasms related to neurofibromin loss.

Analysis of Secreted Proteins from Prepubertal Ovarian Tissues Exposed In Vitro to Cisplatin and LH

It is well known that secreted and exosomal proteins are associated with a broad range of physiological processes involving tissue homeostasis and differentiation. In the present paper, our purpose was to characterize the proteome of the culture medium in which the oocytes within the primordial/primary follicles underwent apoptosis induced by cisplatin (CIS) or were, for the most part, protected by LH against the drug. To this aim, prepubertal ovarian tissues were cultured under control and in the presence of CIS, LH, and CIS + LH. The culture media were harvested after 2, 12, and 24 h from chemotherapeutic drug treatment and analyzed by liquid chromatography-mass spectrometry (LC-MS). We found that apoptotic conditions generated by CIS in the cultured ovarian tissues and/or oocytes are reflected in distinct changes in the extracellular microenvironment in which they were cultured. These changes became evident mainly from 12 h onwards and were characterized by the inhibition or decreased release of a variety of compounds, such as the proteases Htra1 and Prss23, the antioxidants Prdx2 and Hbat1, the metabolic regulators Ldha and Pkm, and regulators of apoptotic pathways such as Tmsb4x. Altogether, these results confirm the biological relevance of the LH action on prepuberal ovaries and provide novel information about the proteins released by the ovarian tissues exposed to CIS and LH in the surrounding microenvironment. These data might represent a valuable resource for future studies aimed to clarify the effects and identify biomarkers of these compounds' action on the developing ovary.

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 (MON^SB3+ ) cells in immune-deficient NOD-SCID/IL2Rg^null  (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, MON^SB3+ 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, MON^SB3+ 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, MON^SB3+ 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.

Elevation of Serum SSCCAII in Cutaneous and Oral Lichen Planus: Missing Link for Hidden Carcinogenic Potential?

Context:

Lichen planus (LP) is an immune mediated inflammatory condition. SCCAII is a useful biomarker reflecting Th17 type inflammation. It is also a tumour marker, especially for Squamous cell carcinoma (SCC) Mechanism of carcinogenesis in LP is still unknown. Chronic inflammation may facilitate the development of cellular clones in the epidermis.

Aims:

Estimation of serum level of SCCA II in patients with cutaneous and oral LP (OLP) to detect its role in LP pathogenesis, and to reveal the missing link in understanding mechanism of carcinogenesis in LP.

Methods and Material:

A case control study, where 100 subjects were included; 80 LP patients (40 cutaneous & 40 oral) and 20 apparently healthy controls. We obtained an informed written consent from each subject prior the participation. Cutaneous and oral LP were diagnosed clinically, SCCA II level was measured by ELISA technique.

Statistical analysis used:

Statistical analysis was done using SPSS vs.25. (IBM, Armonk, New York, United states). Numerical data was summarized as means and standard deviations or medians and ranges.

Results:

Median SSCCAII level was significantly higher in LP cases compared to controls (P < 0.001) and was significantly higher in patients with OLP compared to patients with cutaneous LP (P ≤ 0.001). Post hoc analysis revealed that median SSCCAII was significantly higher in patients with ulcerative type compared to both reticular type and others. It was also significantly higher in patients with actinic type compared to both hypertrophic type and classic type. Median SSCCAII was significantly higher in patients with ulcerative OLP compared to actinic LP (P < 0.001).

Conclusions:

Our study revealed that serum SCCAII level was higher in patients with cutaneous and OLP. This might be linked to the pathogenesis of LP, especially actinic and erosive OLP. SCCAII level could facilitate the screening and early detection of patients at risk, a potential alarm to launch accurate assessment and continue follow up of cutaneous as well as O LP patients.

Engineered EVs for Oxidative Stress Protection

Extracellular vesicles (EVs) are increasingly studied as vectors for drug delivery because they can transfer a variety of molecules across biological barriers. SerpinB3 is a serine protease inhibitor that has shown a protective anti-apoptotic function in a variety of stressful conditions. The aim of this study was to evaluate protection from oxidative stress-induced damage, using extracellular vesicles that overexpress SerpinB3 (EVs-SB3) in order to enhance the effect of extracellular vesicles on cellular homeostasis. EVs-SB3s were obtained from HepG2 cells engineered to overexpress SerpinB3 and they revealed significant proteomic changes, mostly characterized by a reduced expression of other proteins compared with EVs from non-engineered cells. These EV preparations showed a significantly higher protection from H₂O₂ induced oxidative stress in both the hepatoma cell line and in primary cardiomyocytes, compared to cells treated with naïve EVs or SerpinB3 alone, used at the same concentration. In conclusion, the induction of SerpinB3 transgene expression results in the secretion of EVs enriched with the protein product that exhibits enhanced cytoprotective activity, compared with naïve EVs or the nude SerpinB3 protein.

Low P66shc with High SerpinB3 Levels Favors Necroptosis and Better Survival in Hepatocellular Carcinoma

Simple Summary

Cell proliferation and escape from apoptosis are important pathological features of hepatocellular carcinoma, one of the tumors with the highest mortality rate worldwide. The aim of the study was to evaluate the expression of the pro-apoptotic p66shc and the anti-apoptotic SerpinB3 molecules in relation to clinical outcome in patients with hepatocellular carcinoma and to evaluate their effect on cell fate and tumor growth. In patients with hepatocellular carcinoma the best survival was observed in the subgroup with p66shc levels below median values and SerpinB3 levels above median values. Mice p66shc knockout showed high levels of SerpinB3, while in hepatoma cells overexpressing SerpinB3, p66shc expression was trivial. Hepatoma cells overexpressing SerpinB3 were more prone to die after oxidizing treatments. These cells injected in nude mice developed tumors five times smaller than those from controls. Tumors originating from hepatoma cells overexpressing SerpinB3 showed typical features of necroptosis. In conclusion, in patients affected by hepatocellular carcinoma, the pattern characterized by p66shc downregulation and elevated SerpinB3 levels was associated with markedly better survival. This pattern favored necroptosis in experimental high-stress conditions.

Abstract

Cell proliferation and escape from apoptosis are important pathological features of hepatocellular carcinoma (HCC), one of the tumors with the highest mortality rate worldwide. The aim of the study was to evaluate the expression of the pro-apoptotic p66shc and the anti-apoptotic SerpinB3 in HCCs in relation to clinical outcome, cell fate and tumor growth. p66shc and SerpinB3 were evaluated in 67 HCC specimens and the results were correlated with overall survival. Proliferation and cell death markers were analyzed in hepatoma cells overexpressing SerpinB3, under different stress conditions. p66shc^−/− mice and xenograft models were also used to assess the effects of p66shc and SerpinB3 on tumor growth. In patients with HCC, the best survival was observed in the subgroup with p66shc levels below median values and SerpinB3 levels above median values. Mice p66shc^−/− showed high levels of SerpinB3, while in HepG2 cells overexpressing SerpinB3, p66shc expression was trivial. HepG2 overexpressing SerpinB3 cells were more prone to die after oxidizing treatments, such as diamide or high concentration H₂O₂. These cells injected in nude mice developed tumors five times smaller than those from control HepG2 cells. Tumors originating from HepG2 overexpressing SerpinB3 cells showed decreased activated Caspase-8, with concomitant increase of RIP3K and decreased levels of cleaved RIP3K, typical features of necroptosis. In conclusion, in patients affected by HCC, the pattern characterized by p66shc downregulation and elevated SerpinB3 levels was associated with markedly better survival. This pattern favored necroptosis in experimental high-stress conditions.

The Determining Role of Mitochondrial Reactive Oxygen Species Generation and Monoamine Oxidase Activity in Doxorubicin-Induced Cardiotoxicity

Aims: Doxorubicin cardiomyopathy is a lethal pathology characterized by oxidative stress, mitochondrial dysfunction, and contractile impairment, leading to cell death. Although extensive research has been done to understand the pathophysiology of doxorubicin cardiomyopathy, no effective treatments are available. We investigated whether monoamine oxidases (MAOs) could be involved in doxorubicin-derived oxidative stress, and in the consequent mitochondrial, cardiomyocyte, and cardiac dysfunction. Results: We used neonatal rat ventricular myocytes (NRVMs) and adult mouse ventricular myocytes (AMVMs). Doxorubicin alone (i.e., 0.5 μM doxorubicin) or in combination with H₂O₂ induced an increase in mitochondrial formation of reactive oxygen species (ROS), which was prevented by the pharmacological inhibition of MAOs in both NRVMs and AMVMs. The pharmacological approach was supported by the genetic ablation of MAO-A in NRVMs. In addition, doxorubicin-derived ROS caused lipid peroxidation and alterations in mitochondrial function (i.e., mitochondrial membrane potential, permeability transition, redox potential), mitochondrial morphology (i.e., mitochondrial distribution and perimeter), sarcomere organization, intracellular [Ca²⁺] homeostasis, and eventually cell death. All these dysfunctions were abolished by MAO inhibition. Of note, in vivo MAO inhibition prevented chamber dilation and cardiac dysfunction in doxorubicin-treated mice. Innovation and Conclusion: This study demonstrates that the severe oxidative stress induced by doxorubicin requires the involvement of MAOs, which modulate mitochondrial ROS generation. MAO inhibition provides evidence that mitochondrial ROS formation is causally linked to all disorders caused by doxorubicin in vitro and in vivo. Based upon these results, MAO inhibition represents a novel therapeutic approach for doxorubicin cardiomyopathy.

Proteomics of Cytochrome c Oxidase-Negative versus -Positive Muscle Fiber Sections in Mitochondrial Myopathy

The mosaic distribution of cytochrome c oxidase⁺ (COX⁺) and COX^- muscle fibers in mitochondrial disorders allows the sampling of fibers with compensated and decompensated mitochondrial function from the same individual. We apply laser capture microdissection to excise individual COX⁺ and COX^- fibers from the biopsies of mitochondrial myopathy patients. Using mass spectrometry-based proteomics, we quantify >4,000 proteins per patient. While COX⁺ fibers show a higher expression of respiratory chain components, COX^- fibers display protean adaptive responses, including upregulation of mitochondrial ribosomes, translation proteins, and chaperones. Upregulated proteins include C1QBP, required for mitoribosome formation and protein synthesis, and STOML2, which organizes cardiolipin-enriched microdomains and the assembly of respiratory supercomplexes. Factoring in fast/slow fiber type, COX^- slow fibers show a compensatory upregulation of beta-oxidation, the AAA⁺ protease AFG3L1, and the OPA1-dependent cristae remodeling program. These findings reveal compensatory mechanisms in muscle fibers struggling with energy shortage and metabolic stress.

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.

A transcriptional signature accurately identifies Aspergillus Infection across healthy and immunosuppressed states

Invasive aspergillosis (IA) is a major cause of critical illness in immunocompromised (IC) patients. However, current fungal tests are limited. Disease-specific gene expression patterns in circulating host cells show promise as novel diagnostics, however it is unknown whether such a 'signature' exists for IA and the effect of iatrogenic immunosuppression on any such biomarkers. Male BALB/c mice were separated into 6 experimental groups based on Aspergillus fumigatus inhalational exposure and IC status (no immunosuppression, cyclophosphamide, and corticosteroids). Mice were sacrificed 4 days postinfection. Whole blood was assayed for transcriptomic responses in peripheral white blood cells via microarray. An elastic net regularized logistic regression was employed to develop classifiers of IA based on gene expression. Aspergillus infection triggers a powerful response in non-IC hosts with 2718 genes differentially expressed between IA and controls. We generated a 146-gene classifier able to discriminate between non-IC infected and uninfected mice with an AUC of 1. However, immunosuppressive medications exhibited a confounding effect on this transcriptomic classifier. After controlling for the genomic effects of immunosuppression, we were able to generate a 187-gene classifier with an AUC of 0.92 in the absence of immunosuppression, 1 with cyclophosphamide, and 0.9 with steroids. The host transcriptomic response to IA is robust and conserved. Pharmacologic perturbation of the host immune response has powerful effects on classifier performance and must be considered when developing such novel diagnostics. When appropriately designed, host-derived peripheral blood transcriptomic responses demonstrate the ability to accurately diagnose Aspergillus infection, even in the presence of immunosuppression.

Au(iii)-Proline derivatives exhibiting selective antiproliferative activity against HepG2/SB3 apoptosis-resistant cancer cells

This paper deals with the combination of a proline-based moiety with biologically active gold centers in the oxidation states +1 and +3. In particular, six Au(i)/(iii)-proline dithiocarbamato (DTC) complexes with general formulae [Au(DTC)₂] and [Au^IIIX₂(DTC)] (X = Cl, Br) are reported here. After the synthesis of the ligand and the complexes, all derivatives were characterized via several techniques and tested for their stability in DMSO/water media. This study was focused on the demonstration of a peculiar behavior of Au(iii)-DTC species in solution. Finally, the complexes were screened for their antiproliferative activity against 2 human cancer cell lines, namely HepG2 and HepG2/SB3, taken as models of hepatocellular carcinoma. The latter, chosen for its aggressiveness due to the upregulation of the anti-apoptotic protein SerpinB3, was selectively inhibited in terms of growth by some Au(iii)-DTC complexes.

Recent trends in predictive biomarkers for determining malignant potential of oral potentially malignant disorders

Despite of the tremendous advancements in the field of cancer prevention, detection and treatment, the overall prognosis of oral squamous cell carcinoma (OSCC) still remains poor. This can be partly imparted to the lack of early detection of oral potentially malignant disorders (OPMDs), especially those at a higher risk of progression into OSCC. Over years, various specific and non-specific markers have been introduced that could predict the malignant transformation of OPMDs; however detail information on these OPMD markers in a concise manner is lacking. Moreover, their use on daily clinical basis still remains questionable. With continuous research in the field of cytology and genomics, several contemporary biomarkers have been discovered that are not yet foregrounded and proved to be more promising than those used conventionally. Here, in the present paper, we overview several recently concluded predictive biomarkers with special emphasis on their role in molecular pathogenesis of OSCC transformation. These markers can be used for risk assessment of malignant transformation in patients with OPMDs as well as for prophylactic conciliation and fair management of the high-risk OPMD patient group.

Radioresistance of Serpinb3a-/- Mice and Derived Hematopoietic and Marrow Stromal Cell Lines

Serpins are a group of serine-proteases involved in multiple signal transduction pathways in mammalian cells. In particular, Serpinb3a is involved in the lysosomal necrosis cell death pathway with components that overlap with radiation-induced apoptosis. We investigated the radiation response of Serpinb3a-/- mice compared to Serpinb3a+/+ mice on the Balb/c background. Serpinb3a-/- mice showed significant radioresistance to a dose of 8.0 Gy total-body irradiation, compared to Serpinb3a+/+ Balb/c mice. Long-term bone marrow cultures from Serpinb3a-/- mice showed increased longevity. In clonogenic survival assays, fresh bone marrow hematopoietic progenitors, as well as clonal interleukin-3 (IL-3)-dependent hematopoietic progenitor and bone marrow stromal cell lines from Serpinb3a-/- mice were radioresistant. Serpinb3a-/- mouse bone marrow-derived stromal cell lines had increased baseline and postirradiation antioxidant capacity. Serpinb3a-/- bone marrow stromal cells showed increased radiation-induced RNA transcripts for MnSOD and p21, and decreased levels of p53 and TGF-b. Both irradiated Serpinb3a-/- mouse bone marrow stromal cell lines and plasma removed from total-body irradiated mice had decreased levels of expression of stress response and inflammation-associated proteins. Abrogation of Serpinb3a may be a potential new target for mitigation of radiation effects.

Squamous cell carcinoma antigen 1 is associated to poor prognosis in esophageal cancer through immune surveillance impairment and reduced chemosensitivity

Squamous cell carcinoma antigen‐1 (SCCA1) overexpression is associated with poor prognosis and chemoresistance in several tumor types, however, the underlying mechanisms remain elusive. Here, we report SCCA1 in relation to the immune and peritumoral adipose tissue microenvironment in early and advanced esophageal adenocarcinoma (EAC). In our series of patients with EAC, free SCCA1 serum levels were associated with significantly worse overall survival, and SCCA1‐IgM serum levels showed a trend to a worse overall survival. Serum SCCA1 and intratumoral SCCA1 were inversely correlated with immune activation markers. In agreement with these findings, SCCA1 induced the expression of the immune checkpoint molecule programmed death ligand‐1 on monocytes and a direct correlation of these 2 molecules was observed in sequential tumor sections. Furthermore, SCCA1 mRNA expression within the tumor was inversely correlated with stem cell marker expression both within the tumor and in the peritumoral adipose tissue. In vitro, in EAC cell lines treated with different chemotherapeutic drugs, cell viability was significantly modified by SCCA1 presence, as cells overexpressing SCCA1 were significantly more resistant to cell death. In conclusion, poor prognosis in EAC overexpressing SCCA1 is due to reduced tumor chemosensitivity as well as intratumoral immunity impairment, likely induced by this molecule.

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.

SERPINB3 Delays Glomerulonephritis and Attenuates the Lupus-Like Disease in Lupus Murine Models by Inducing a More Tolerogenic Immune Phenotype

Objective: To explore the effects of SERPINB3 administration in murine lupus models with a focus on lupus-like nephritis.

Methods: 40 NZB/W F1 mice were subdivided into 4 groups and intraperitoneally injected with recombinant SERPINB3 (7.5 μg/0.1 mL or 15 μg/0.1 mL) or PBS (0.1 mL) before (group 1 and 2) or after (group 3 and 4) the development of proteinuria (≥100 mg/dl). Two additional mice groups were provided by including 20 MRL/lpr mice which were prophylactically injected with SERPINB3 (10 mice, group 5) or PBS (10 mice, group 6). Time of occurrence and levels of anti-dsDNA and anti-C1q antibodies, proteinuria and serum creatinine, overall- and proteinuria-free survival were assessed in mice followed up to natural death. Histological analysis was performed in kidneys of both lupus models. The Th17:Treg cell ratio was assessed by flow-cytometry in splenocytes of treated and untreated MRL/lpr mice. Statistical analysis was performed using non parametric tests and Kaplan-Meier curves, when indicated.

Results: Autoantibody levels and proteinuria were significantly decreased and time of occurrence significantly delayed in SERPINB3-treated mice vs. controls. In agreement with these findings, proteinuria-free and overall survival were significantly improved in SERPINB3-treated groups vs. controls. Histological analysis demonstrated a lower prevalence of severe tubular lesions in kidneys of group 5 vs. group 6. SERPINB3-treated mice showed an overall trend toward a reduced prevalence of severe lesions in both strains. Th17:Treg ratio was significantly decreased in splenocytes of MRL/lpr mice treated with SERPINB3, compared to untreated control mice.

Conclusions: SERPINB3 significantly improves disease course and delays the onset of severe glomerulonephritis in lupus-prone mice, possibly inducing a more tolerogenic immune phenotype.

Targeting Mitochondrial Ion Channels to Fight Cancer

In recent years, several experimental evidences have underlined a new role of ion channels in cancer development and progression. In particular, mitochondrial ion channels are arising as new oncological targets, since it has been proved that most of them show an altered expression during tumor development and the pharmacological targeting of some of them have been demonstrated to be able to modulate cancer growth and progression, both in vitro as well as in vivo in pre-clinical mouse models. In this scenario, pharmacology of mitochondrial ion channels would be in the near future a new frontier for the treatment of tumors. In this review, we discuss the new advances in the field, by focusing our attention on the improvements in new drug developments to target mitochondrial ion channels.

Squamous Cell Carcinoma Antigen 2 (SCCA2, SERPINB4): An Emerging Biomarker for Skin Inflammatory Diseases

Squamous cell carcinoma antigens 1 and 2 (SCCA1 and 2, SERPIN B3 and B4), members of the ovalbumin serpin (ov-serpin)/clade B serpin family, were originally discovered as tumor-specific antigens and are used as tumor markers for various kinds of squamous cell carcinomas. Recently, our understanding of the underlying mechanisms of how SCCA1/2 enhance tumor growth has greatly increased. Moreover, it has been shown that SCCA1/2 are involved in the pathogenesis of several inflammatory diseases: asthma, psoriasis, and atopic dermatitis (AD). IL-22 and IL-17, signature cytokines of type 17 inflammation, as well as IL-4 and IL-13, signature cytokines of type 2 inflammation, both of which are positively correlated with the pathogenesis of psoriasis and allergic diseases, respectively, can induce expression of SCCA1/2 in airway epithelial cells and/or keratinocytes, leading to high expression of SCCA1/2 in these diseases. Based on these findings, several trials have been performed to examine the potential of applying SCCA1/2 to biomarkers for these diseases. The findings show that SCCA2 is useful to aid diagnosis, estimate clinical severity and disease type, and assess responses to treatment in psoriasis and AD. These results suggest that SCCA2 has emerged as a novel biomarker for skin inflammatory diseases.

Squamous cell carcinoma antigen (SCCA) is up-regulated during Barrett's carcinogenesis and predicts esophageal adenocarcinoma resistance to neoadjuvant chemotherapy

Squamous Cell Carcinoma Antigen (SCCA) is consistently overexpressed in many different solid tumors, and has been associated with both tumor aggressiveness and chemoresistance. No data, however, is currently available on SCCA expression during esophageal Barrett's carcinogenesis, nor on SCCA expression's role on esophageal adenocarcinoma chemoresistance. The SCCA immunohistochemical expression was assessed in a series of 100 biopsy samples covering the whole histological spectrum of Barrett's oncogenesis. Squamous native mucosa was characterized by a moderate to strong cytoplasmic and nuclear SCCA expression in suprabasal, medium, and superficial layers. On the other hand, almost half of the considered lesions did not express SCCA; the other half featured weak to moderate SCCA expression. The relationship between SCCA protein expression and tumor response to neoadjuvant chemotherapy was assessed in 90 esophageal adenocarcinoma specimens (40 biopsy and 50 surgery specimens), stratified according to Mandard tumor regression grade. As observed in other settings, the presence of SCCA expression clustered in the group of tumors characterized by a lower responsiveness to neoadjuvant treatments. The present results suggest an involvement of SCCA in a subset of Barrett-related tumors, and prompt to consider the SCCA-protein expression as response-predictive marker of neoadjuvant therapy in esophageal adenocarcinomas.

Synthesis, chemical characterization and cancer cell growth-inhibitory activities of Cu(ii) and Ru(iii) aliphatic and aromatic dithiocarbamato complexes

The effects mediated by different cyclic dithiocarbamic ligands on three classes of antiproliferative coordination compounds were studied.

Buserelin alleviates chloride transport defect in human cystic fibrosis nasal epithelial cells

Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) chloride (Cl-) channel regulated by protein kinases, phosphatases, divalent cations and by protein-protein interactions. Among protein-protein interactions, we previously showed that Annexin A5 (AnxA5) binds to CFTR and is involved in the channel localization within membranes and in its Cl- channel function. The deletion of phenylalanine at position 508 (F508del) is the most common mutation in CF which leads to an altered protein (F508del-CFTR) folding with a nascent protein retained within the ER and is quickly degraded. We previously showed that AnxA5 binds to F508del-CFTR and that its increased expression due to a Gonadoliberin (GnRH) augments Cl- efflux in cells expressing F508del-CFTR. The aim of the present work was to use the GnRH analog buserelin which is already used in medicine. Human nasal epithelial cells from controls and CF patients (F508del/F508del) were treated with buserelin and we show here that the treatment alleviates Cl- channel defects in CF cells. Using proteomics we highlighted some proteins explaining this result. Finally, we propose that buserelin is a potential new pharmaceutical compound that can be used in CF and that bronchus can be targeted since we show here that they express GnRH-R.

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.

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.

Astragalin Reduces Hexokinase 2 through Increasing miR-125b to Inhibit the Proliferation of Hepatocellular Carcinoma Cells in Vitro and in Vivo

Astragalin (ASG) can be found in a variety of food components. ASG exhibits cytotoxic effects on several different types of malignant cells. However, its effects on hepatocellular carcinoma (HCC) cells and the underlying molecular mechanisms have remained to be fully elucidated. Here, we revealed that ASG remarkably suppressed the proliferation of HCC cells. In HCC cells, ASG inhibited glucose glycolysis and promoted oxidative phosphorylation, resulting in a surge of reactive oxygen species (ROS). Mechanistically, ASG suppressed the expression of hexokinase 2 (HK2). This event was indispensible for ASG-mediated metabolic reprogramming, ROS accumulation, and subsequent growth arrest. Our further investigations unveiled that ASG repressed HK2 expression via increasing miR-125b. In vivo experiments showed that gavage of ASG decreased the proliferation of Huh-7 HCC xenografts in nude mice and inhibited the growth of transplanted H22 HCC cells in Kunming mice. Declined HCC tumor growth in vivo was associated with boosted miR-125b and reduced expression of HK2 in tumor tissues. Collectively, our results demonstrated that ASG is able to suppress the proliferation of HCC cells both in vitro and in vivo. Inhibition of HK2 through upregulating miR-125b and subsequent metabolic reprogramming is implicated in the antiproliferative effects of ASG on HCC cells.

Circulating SCCA-IgM complex is a useful biomarker to predict the outcome of therapy in hepatocellular carcinoma patients

INTRODUCTION

Hepatocellular carcinoma (HCC) develops in about 3-4% of cirrhotic patients every year. The squamous cell carcinoma antigen (SCCA) has been found elevated in liver cancer specimens by immunohistochemistry, and detected in complex with IgM (SCCA-IgM) in the serum of patients with HCC. The aim of this study was to evaluate the ability of serological SCCA-IgM levels to predict the efficacy of HCC therapy.

MATERIALS AND METHODS

From April 2012 to April 2014, 131 patients with a new diagnosis of HCC were enrolled. The HCC diagnosis was made according to the EASL guidelines. The patients were staged and treated according to the BCLC Staging System: BCLC stages A and B were treated with locoregional therapy, and BCLC stage C was treated with Sorafenib. Response to therapy was evaluated according to the mRECIST criteria. Serum SCCA-IgM levels were determined by a commercially available ELISA kit at basal time (T₀) and after one month of treatment (T₁).

RESULTS

At baseline and one month into therapy, SCCA-IgM levels were significantly lower (p value <.05) in patients who responded to therapy compared to those who did not respond (median SCCA-IgM level [25th + 75th percentile] at T₀:115.1 AU/mL [50.0 + 174.4] vs. 149.1 AU/mL [111.3 + 198.8]; median SCCA-IgM level [25th + 75th percentile] at T₁: 113.4 AU/mL [50.0 + 194.2] vs. 170.6 AU/mL [111.7 + 344.2]).

CONCLUSION

Our study suggests that the SCCA-IgM determination could be helpful in predicting the response to therapy in patients with HCC.

Impact of intracellular ion channels on cancer development and progression

Cancer research is nowadays focused on the identification of possible new targets in order to try to develop new drugs for curing untreatable tumors. Ion channels have emerged as "oncogenic" proteins, since they have an aberrant expression in cancers compared to normal tissues and contribute to several hallmarks of cancer, such as metabolic re-programming, limitless proliferative potential, apoptosis-resistance, stimulation of neo-angiogenesis as well as cell migration and invasiveness. In recent years, not only the plasma membrane but also intracellular channels and transporters have arisen as oncological targets and were proposed to be associated with tumorigenesis. Therefore, the research is currently focusing on understanding the possible role of intracellular ion channels in cancer development and progression on one hand and, on the other, on developing new possible drugs able to modulate the expression and/or activity of these channels. In a few cases, the efficacy of channel-targeting drugs in reducing tumors has already been demonstrated in vivo in preclinical mouse models.

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.

Inhibition of glucose-6-phosphate dehydrogenase sensitizes cisplatin-resistant cells to death

The mechanisms of cisplatin resistance, one of the major limitations of current chemotherapy, has only partially been described. We previously demonstrated that cisplatin-resistant ovarian cancer cells (C13), are characterized by reduced mitochondrial activity and higher glucose-dependency when compared to the cisplatin-sensitive counterpart (2008). In this work we further characterized the role of metabolic transformation in cisplatin resistance. By using transmitochondrial hybrids we show that metabolic reprogramming of cisplatin-resistant cell is not caused by inherent mtDNA mutations. We also found that C13 cells not only present an increased glucose-uptake and consumption, but also exhibit increased expression and enzymatic activity of the Pentose Phosphate pathway (PPP) enzyme Glucose-6-Phosphate Dehydrogenase (G6PDH). Moreover, we show that cisplatin-resistant cells are more sensitive to G6PDH inhibition. Even if the metabolomic fingerprint of ovarian cancer cells remains to be further elucidated, these findings indicate that PPP offers innovative potential targets to overcome cisplatin resistance.

Arsenic trioxide plus PX-478 achieves effective treatment in pancreatic ductal adenocarcinoma

Arsenic trioxide (ATO) has been selected as a promising treatment not only in leukemia but also in solid tumors. Previous studies showed that the cytotoxicity of ATO mainly depends on the induction of reactive oxygen species. However, ATO has only achieved a modest effect in pancreatic ductal adenocarcinoma, suggesting that the existing radical scavenging proteins, such as hypoxia inducible factor-1, attenuate the effect. The goal of this study is to investigate the effect of combination treatment of ATO plus PX-478 (hypoxia-inducible factor-1 inhibitor) and its underlying mechanism. Here, we showed that PX-478 robustly strengthened the anti-growth and pro-apoptosis effect of ATO on Panc-1 and BxPC-3 pancreatic cancer cells in vitro. Meanwhile, in vivo mouse xenograft models also showed the synergistic effect of ATO plus PX-478 compared with any single agent. Further studies showed that the anti-tumor effect of ATO plus PX-478 was derived from the reactive oxygen species-induced apoptosis. We next confirmed that Hypoxia-inducible factor-1 cleared reactive oxygen species by its downstream target, forkhead box O transcription factors, and this effect may justify the strategy of ATO plus PX-478 in the treatment of pancreatic cancer.

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.

ZNF32 protects against oxidative stress-induced apoptosis by modulating C1QBP transcription

Reactive oxygen species (ROS)-driven oxidative stress has been recognized as a critical inducer of cancer cell death in response to therapeutic agents. Our previous studies have demonstrated that zinc finger protein (ZNF)32 is key to cell survival upon oxidant stimulation. However, the mechanisms by which ZNF32 mediates cell death remain unclear. Here, we show that at moderate levels of ROS, Sp1 directly binds to two GC boxes within the ZNF32 promoter to activate ZNF32 transcription. Alternatively, at cytotoxic ROS concentrations, ZNF32 expression is repressed due to decreased binding activity of Sp1. ZNF32 overexpression maintains mitochondrial membrane potential and enhances the antioxidant capacity of cells to detoxify ROS, and these effects promote cell survival upon pro-oxidant agent treatment. Alternatively, ZNF32-deficient cells are more sensitive and vulnerable to oxidative stress-induced cell injury. Mechanistically, we demonstrate that complement 1q-binding protein (C1QBP) is a direct target gene of ZNF32 that inactivates the p38 MAPK pathway, thereby exerting the protective effects of ZNF32 on oxidative stress-induced apoptosis. Taken together, our findings indicate a novel mechanism by which the Sp1-ZNF32-C1QBP axis protects against oxidative stress and implicate a promising strategy that ZNF32 inhibition combined with pro-oxidant anticancer agents for hepatocellular carcinoma treatment.

The Mitochondrial Permeability Transition Pore: Channel Formation by F-ATP Synthase, Integration in Signal Transduction, and Role in Pathophysiology

The mitochondrial permeability transition (PT) is a permeability increase of the inner mitochondrial membrane mediated by a channel, the permeability transition pore (PTP). After a brief historical introduction, we cover the key regulatory features of the PTP and provide a critical assessment of putative protein components that have been tested by genetic analysis. The discovery that under conditions of oxidative stress the F-ATP synthases of mammals, yeast, and Drosophila can be turned into Ca(2+)-dependent channels, whose electrophysiological properties match those of the corresponding PTPs, opens new perspectives to the field. We discuss structural and functional features of F-ATP synthases that may provide clues to its transition from an energy-conserving into an energy-dissipating device as well as recent advances on signal transduction to the PTP and on its role in cellular pathophysiology.

Inhibition of succinate dehydrogenase by the mitochondrial chaperone TRAP1 has anti-oxidant and anti-apoptotic effects on tumor cells

TRAP1 is a mitochondrial chaperone highly expressed in many tumor types; it inhibits respiratory complex II, down-modulating its succinate dehydrogenase (SDH) enzymatic activity. SDH inhibition in turn leads to a pseudohypoxic state caused by succinate-dependent HIF1α stabilization and promotes neoplastic growth. Here we report that TRAP1 inhibition of SDH also shields cells from oxidative insults and from the ensuing lethal opening of the mitochondrial permeability transition pore. This anti-oxidant activity of TRAP1 protects tumor cells from death in conditions of nutrient paucity that mimic those encountered in the neoplasm during the process of malignant accrual, and it is required for in vitro tumorigenic growth. Our findings demonstrate that SDH inhibition by TRAP1 is oncogenic not only by inducing pseudohypoxia, but also by protecting tumor cells from oxidative stress.

Mitofusin 2 ablation increases endoplasmic reticulum-mitochondria coupling

The organization and mutual interactions between endoplasmic reticulum (ER) and mitochondria modulate key aspects of cell pathophysiology. Several proteins have been suggested to be involved in keeping ER and mitochondria at a correct distance. Among them, in mammalian cells, mitofusin 2 (Mfn2), located on both the outer mitochondrial membrane and the ER surface, has been proposed to be a physical tether between the two organelles, forming homotypic interactions and heterocomplexes with its homolog Mfn1. Recently, this widely accepted model has been challenged using quantitative EM analysis. Using a multiplicity of morphological, biochemical, functional, and genetic approaches, we demonstrate that Mfn2 ablation increases the structural and functional ER-mitochondria coupling. In particular, we show that in different cell types Mfn2 ablation or silencing increases the close contacts between the two organelles and strengthens the efficacy of inositol trisphosphate (IP3)-induced Ca(2+) transfer from the ER to mitochondria, sensitizing cells to a mitochondrial Ca(2+) overload-dependent death. We also show that the previously reported discrepancy between electron and fluorescence microscopy data on ER-mitochondria proximity in Mfn2-ablated cells is only apparent. By using a different type of morphological analysis of fluorescent images that takes into account (and corrects for) the gross modifications in mitochondrial shape resulting from Mfn2 ablation, we demonstrate that an increased proximity between the organelles is also observed by confocal microscopy when Mfn2 levels are reduced. Based on these results, we propose a new model for ER-mitochondria juxtaposition in which Mfn2 works as a tethering antagonist preventing an excessive, potentially toxic, proximity between the two organelles.

Squamous cell carcinoma antigen in hepatocellular carcinoma: Ready for the prime time?

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and the third cause of cancer deaths. The leading predisposing condition is represented by an underlying viral hepatitis, mainly sustained by hepatitis B and C viruses. Since the cumulative risk of developing HCC can be as high as 30-fold in patients with infectious cirrhosis, a timely diagnosis is necessary for establishing an appropriate treatment in these patients. The armamentarium of diagnostic and prognostic biomarkers in patients with HCC currently entails alpha-fetoprotein (AFP) and a limited number of innovative biomarkers, among which squamous cell carcinoma antigen (SCCA) and its immune complexes are among the most widely investigated. The clinical data published so far and reviewed in this article seemingly suggest that neither total serum SSCA or its isoform 1 (i.e., SCCA1) may be ready for the prime time for management of patients with HCC. More interesting evidence has emerged from studies investigating the serum values of SCCA-IgM, since the diagnostic performance of this biomarker was found to be frequently superior to that of AFP and, even more importantly, the combination of SCCA-IgM and AFP was characterized by a much better sensitivity than either biomarker alone, with only a modest decrease of specificity. Larger studies are needed before these preliminary findings can be generalized, but the combined use of AFP and SCCA-IgM represents an appealing perspective in diagnosis and prognostication of HCC.

Reprint of "The mitochondrial permeability transition pore and its adaptive responses in tumor cells"

This review covers recent progress on the nature of the mitochondrial permeability transition pore (PTP) – a key effector in the mitochondrial pathways to cell death – and on the adaptive responses of tumor cells that desensitize the PTP to Ca(2+) and reactive oxygen species (ROS), thereby playing an important role in the resistance of tumors to cell death. The discovery that the PTP forms from dimers of F-ATP synthase; and the definition of the Ca(2+)- and ROS-dependent signaling pathways affecting the transition of the F-ATP synthase from an energy-conserving to an energy-dissipating device open new perspectives for therapeutic intervention in cancer cells.

SERPINB3 (serpin peptidase inhibitor, clade B (ovalbumin), member 3)

Review on SERPINB3, with data on DNA/RNA, on the protein encoded and where the gene is implicated.

The mitochondrial permeability transition pore and its adaptive responses in tumor cells

This review covers recent progress on the nature of the mitochondrial permeability transition pore (PTP) - a key effector in the mitochondrial pathways to cell death - and on the adaptive responses of tumor cells that desensitize the PTP to Ca(2+) and reactive oxygen species (ROS), thereby playing an important role in the resistance of tumors to cell death. The discovery that the PTP forms from dimers of F-ATP synthase; and the definition of the Ca(2+)- and ROS-dependent signaling pathways affecting the transition of the F-ATP synthase from an energy-conserving to an energy-dissipating device open new perspectives for therapeutic intervention in cancer cells.