Tumor cell-expressed SerpinB2 is present on microparticles and inhibits metastasis

SerpinB2 deficiency is associated with delayed mammary tumor development and decreased pro-tumorigenic macrophage polarization

The in vivo functions of SerpinB2 in tumor cells and tumor-associated macrophages (TAMs) during breast cancer development and metastasis remain elusive. SerpinB2-deficient MMTV-PyMT mice (PyMTSB2-/-) were previously produced to explore the biological roles of SerpinB2 in breast cancer. Compared with MMTV-PyMT wild-type (PyMTWT) mice, PyMTSB2-/- mice showed delayed tumor progression and reduced CK8 + tumor cell dissemination to lymph nodes. RNA-Seq data revealed significantly enriched genes associated with inflammatory responses, especially upregulated M1 and downregulated M2 macrophage marker genes in PyMTSB2-/- tumors. Decreased CD206+M2 and increased NOS2+M1 markers were detected in the primary tumors and metastatic lymph nodes of PyMTSB2-/- mice. In an in vitro study, SerpinB2 knockdown decreased the sphere formation and migration of MDA-MB-231 cells and suppressed protumorigenic M2 polarization of RAW264.7 cells. The combination of low SerpinB2, high NOS2, and low CD206 expression was favorable for survival in patients with breast cancer, as assessed in the BreastMark dataset. Our study demonstrates that SerpinB2 deficiency delays mammary tumor development and metastasis in PyMTWT mice, along with reduced sphere formation and migration abilities of tumor cells and decreased macrophage protumorigenic polarization.

Genetic deviation associated with photodynamic therapy in HeLa cell

Photodynamic therapy (PDT) is a method that is used in cancer treatment. The main therapeutic effect is the production of singlet oxygen (1O2). Phthalocyanines for PDT produce high singlet oxygen with absorbers of about 600-700 nm.

AIM

It is aimed to analyze cancer cell pathways by flow cytometry analysis and cancer-related genes with q-PCR device by applying phthalocyanine L1ZnPC, which we use as photosensitizer in photodynamic therapy, in HELA cell line. In this study, we investigate the molecular basis of L1ZnPC's anti-cancer activity.

MATERIAL METHOD

The cytotoxic effects of L1ZnPC, a phthalocyanine obtained from our previous study, in HELA cells were evaluated and it was determined that it led to a high rate of death as a result. The result of photodynamic therapy was analyzed using q-PCR. From the data received at the conclusion of this investigation, gene expression values were calculated, and expression levels were assessed using the 2-∆∆Ct method to examine the relative changes in these values. Cell death pathways were interpreted with the FLOW cytometer device. One-Way Analysis of Variance (ANOVA) and the Tukey-Kramer Multiple Comparison Test with Post-hoc Test were used for the statistical analysis.

CONCLUSION

In our study, it was observed that HELA cancer cells underwent apoptosis at a rate of 80% with drug application plus photodynamic therapy by flow cytometry method. According to q-PCR results, CT values ​​of eight out of eighty-four genes were found to be significant and their association with cancer was evaluated. L1ZnPC is a new phthalocyanine used in this study and our findings should be supported by further studies. For this reason, different analyses are needed to be performed with this drug in different cancer cell lines. In conclusion, according to our results, this drug looks promising but still needs to be analyzed through new studies. It is necessary to examine in detail which signaling pathways they use and their mechanism of action. For this, additional experiments are required.

Transcriptome analysis of SerpinB2-deficient breast tumors provides insight into deciphering SerpinB2-mediated roles in breast cancer progression

Background

SerpinB2 is highly expressed in immune and tumor cells and is involved in multiple biological functions, including cell survival and remodeling for disease progression. This study prepared SerpinB2-deficient mice and analyzed the differentially expressed genes (DEGs) to determine if loss of this protein delays mammary tumor progression.

Results

A total of 305 DEGs (75 upregulated and 230 downregulated; > 1.5-fold difference, P < 0.05) were identified in SB2−/−;PyMT tumors compared with PyMT tumors. The DEGs were mainly involved in immune and inflammatory responses related to T cell differentiation, IFN-γ production, and lymphocyte chemotaxis based on 61 enriched GO terms, hierarchical clustering, KEGG pathways, and a functionally grouped annotation network. The significantly changed DEGs (Anxa3, Ccl17, Cxcl13, Cxcr3, IFN-γ, Nr4a1, and Sema3a) annotated with at least two GO categories in SB2−/−;PyMT tumors was validated by qRT-PCR.

Conclusions

SerpinB2 deficiency alters the expression of multiple genes in mammary tumors, which might cause a delay in PyMT-induced mammary tumor progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08704-4.

Knockdown of SERPINB2 enhances the osteogenic differentiation of human bone marrow mesenchymal stem cells via activation of the Wnt/β-catenin signalling pathway

Background

Globally, bone fractures are the most common musculoskeletal trauma, and approximately 8–10% of cases that fall into the categories of delayed or non-union healing. To date, there are no efficient pharmacological agents to accelerate the healing of bone fractures. Thus, it is necessary to find new strategies that accelerate bone healing and reduce the incidence of non-union or delayed fracture healing. Previous studies have revealed that the plasminogen activation system has been demonstrated to play an important role in bone metabolism. However, the function of SERPINB2 in the osteogenesis of hBMSCs remains unclear. Therefore, in this study, we investigated the effects and mechanism of SERPINB2 on osteogenic differentiation.

Methods

We investigated the osteogenesis effects of hBMSCs by both exogenous SerpinB2 protein and SERPINB2 gene silencing in vitro. Cell proliferation assay was used to assess the effect of exogenous SerpinB2 or SERPINB2 silencing on proliferation of hBMSCs. qPCR and Western blotting analysis detected the expression of target genes and proteins respectively. ALP staining was used to evaluated ALP activity and Alizarin Red staining (ARS) was used to evaluate mineral deposition. In vivo, a murie tibial fracture model was established, histological evaluation and radiographic analysis was used to confirm the therapeutic effects of SERPINB2 silencing in fracture healing. Statistical significance between two groups was determined by Student’s t test, one-way ANOVA or Bonferroni’s post-hoc test according to the distribution of the tested population.

Results

The addition of exogenous SerpinB2 protein inhibted osteoblast differentiation of hBMSCs in vitro, while SERPINB2 gene silencing significant promote osteoblast differentiation of hBMSCs in vitro. And silenced SERPINB2 gene also increased mineral deposits. Moreover, β-catenin levels were up-regulated by SERPINB2 gene depletion. And the enhancement of osteogenic differentiation induced by SERPINB2 silencing was almost inhibited by specific Wnt/β-catenin signaling pathway inhibitor. In a murine tibial fracture model, local injection of SERPINB2 siRNA improved bone fracture healing.

Conclusions

Taken together, these findings indicate that SERPINB2 silencing promoted osteogenic differentiation of BMSCs via the Wnt/β-catenin signaling pathway, and silenced SERPINB2 in vivo effectively promotes fracture healing, suggesting that SERPINB2 may be a novel target for bone fracture healing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02581-6.

Identification of lymphocyte cell-specific protein-tyrosine kinase (LCK) as a driver for invasion and migration of oral cancer by tumor heterogeneity exploitation

BACKGROUND

Cancer metastases are the main cause of lethality. The five-year survival rate for patients diagnosed with advanced stage oral cancer is 30%. Hence, the identification of novel therapeutic targets is an urgent need. However, tumors are comprised of a heterogeneous collection of cells with distinct genetic and molecular profiles that can differentially promote metastasis making therapy development a challenging task. Here, we leveraged intratumoral heterogeneity in order to identify drivers of cancer cell motility that might be druggable targets for anti-metastasis therapy.

METHODS

We used 2D migration and 3D matrigel-based invasion assays to characterize the invasive heterogeneity among and within four human oral cancer cell lines in vitro. Subsequently, we applied mRNA-sequencing to map the transcriptomes of poorly and strongly invasive subclones as well as primary tumors and matched metastasis.

RESULTS

We identified SAS cells as a highly invasive oral cancer cell line. Clonal analysis of SAS yielded a panel of 20 subclones with different invasive capacities. Integrative gene expression analysis identified the Lymphocyte cell-specific protein-tyrosine kinase (LCK) as a druggable target gene associated with cancer cell invasion and metastasis. Inhibition of LCK using A-770041 or dasatinib blocked invasion of highly aggressive SAS cells. Interestingly, reduction of LCK activity increased the formation of adherens junctions and induced cell differentiation.

CONCLUSION

Analysis of invasive heterogeneity led to the discovery of LCK as an important regulator of motility in oral cancer cells. Hence, small molecule mediated inhibition of LCK could be a promising anti-metastasis therapy option for oral cancer patients.

Plasminogen activator Inhibitor-2 inhibits pulmonary arterial smooth muscle cell proliferation in pulmonary arterial hypertension via PI3K/Akt and ERK signaling

BACKGROUND

The proliferation of pulmonary arterial smooth muscle cells (PASMCs) and subsequent pulmonary vascular remodeling leads to pulmonary arterial hypertension (PAH). Understanding the underlying mechanisms and identifying molecules that can suppress PASMCs proliferation is critical for developing effective pharmacological treatment. We previously showed that plasminogen activator inhibitor-2 (PAI-2) inhibited human PASMC (hPASMCs) proliferation in vitro. However, its inhibitory effect on PAH remains to be determined, and the mechanism remains to be illustrated.

METHODS

We compared serum PAI-2 levels between PAH patients and healthy controls, and examined the correlation between PAI-2 level and disease severity. In monocrotaline-induced PAH rats, we examined the effects of exogenous PAI-2 administration on pulmonary vascular remodeling and PAH development. The effect of PAI-2 and potential mechanisms was further examined in cultured hPASMCs.

RESULTS

The serum PAI-2 was decreased in PAH patients compared with controls. PAI-2 level was negatively correlated with mean pulmonary arterial pressure and estimated systolic pulmonary arterial pressure in ultrasonic cardiogram, while positively correlated with 6-min walking distance. In rats, administration of exogenous PAI-2 significantly reversed monocrotaline-induced PAH, as indicated by the decrease in right ventricle systolic pressure, right ventricular hypertrophy index and percent media thickness of pulmonary arterioles. Further mechanistic investigation in hPASMCs showed that PAI-2 inhibited cell proliferation by preventing the activation of PI3K/Akt and ERK pathways.

CONCLUSION

PAI-2 is downregulated in PAH patients. PAI-2 attenuates PAH development by suppressing hPASMCs proliferation via the inhibition of PI3K/Akt and ERK pathways. PAI-2 may serve as a potential biomarker and therapeutic target for PAH.

Deficiency of plasminogen activator inhibitor-2 results in accelerated tumor growth

BACKGROUND

Upregulation of the plasminogen activation system, including urokinase plasminogen activator (uPA), has been observed in many malignancies, suggesting that co-opting the PA system is a common method by which tumor cells accomplish extracellular matrix proteolysis. PAI-2, a serine protease inhibitor, produced from the SERPINB2 gene, inhibits circulating and extracellular matrix-tethered uPA. Decreased SERPINB2 expression has been associated with increased tumor invasiveness and metastasis for several types of cancer. PAI-2 deficiency has not been reported in humans and PAI-2-deficient (SerpinB2-/- ) mice exhibit no apparent abnormalities.

OBJECTIVES

We investigated the role of PAI-2 deficiency on tumor growth and metastasis.

METHODS

To explore the long-term impact of PAI-2 deficiency, a cohort of SerpinB2-/- mice were aged to >18 months, with spontaneous malignancies observed in 4/9 animals, all of apparently vascular origin. To further investigate the role of PAI-2 deficiency in malignancy, SerpinB2-/- and wild-type control mice were injected with either B16 melanoma or Lewis lung carcinoma tumor cells, with markedly accelerated tumor growth observed in SerpinB2-/- mice for both cell lines. To determine the relative contributions of PAI-2 from hematopoietic or nonhematopoietically derived sources, bone marrow transplants between wild-type C57BL/6J and SerpinB2-/- mice were performed.

RESULTS AND CONCLUSIONS

Our results suggest that PAI-2 deficiency increases susceptibility to spontaneous tumorigenesis in the mouse, and demonstrate that SerpinB2 expression derived from a nonhematopoietic compartment is a key host factor in the regulation of tumor growth in both the B16 melanoma and Lewis lung carcinoma models.

Mass Spectrometry-Based Proteomic Characterization of Cutaneous Melanoma Ectosomes Reveals the Presence of Cancer-Related Molecules

Cutaneous melanoma (CM) is an aggressive type of skin cancer for which effective biomarkers are still needed. Recently, the protein content of extracellular vesicles (ectosomes and exosomes) became increasingly investigated in terms of its functional role in CM and as a source of novel biomarkers; however, the data concerning the proteome of CM-derived ectosomes is very limited. We used the shotgun nanoLC-MS/MS approach to the profile protein content of ectosomes from primary (WM115, WM793) and metastatic (WM266-4, WM1205Lu) CM cell lines. Additionally, the effect exerted by CM ectosomes on recipient cells was assessed in terms of cell proliferation (Alamar Blue assay) and migratory properties (wound healing assay). All cell lines secreted heterogeneous populations of ectosomes enriched in the common set of proteins. A total of 1507 unique proteins were identified, with many of them involved in cancer cell proliferation, migration, escape from apoptosis, epithelial-mesenchymal transition and angiogenesis. Isolated ectosomes increased proliferation and motility of recipient cells, likely due to the ectosomal transfer of different cancer-promoting molecules. Taken together, these results confirm the significant role of ectosomes in several biological processes leading to CM development and progression, and might be used as a starting point for further studies exploring their diagnostic and prognostic potential.

SERPINB2 and miR-146a/b are coordinately regulated and act in the suppression of psoriasis-associated inflammatory responses in keratinocytes

Psoriasis is a chronic inflammatory skin disease with numerous involved factors. miR-146a and miR-146b (miR-146a/b) are anti-inflammatory miRNAs that are increased in psoriatic skin. SERPINB2 has been shown to be upregulated in the inflammation and infections. Here we aimed to study the relationship between miR-146a/b and SERPINB2 and to delineate the role of SERPINB2 in association of plaque psoriasis. We report increased SERPINB2 expression in the skin of psoriasis patients, which was in a positive relationship with psoriasis severity and in a negative relationship with miR-146a/b in psoriatic lesions. In cultured keratinocytes, both cellular and secreted SERPINB2 levels were strongly induced in response to IFN-γ and TNF-α. Interestingly, SERPINB2 mRNA was downregulated by IL-17A and the combination of TNF-α and IL-17A at time points when miR-146a was increased. The predicted binding site for miR-146a/b in 3' untranslated region of SERPINB2 revealed no activity in luciferase assay, while siRNA silencing of miR-146a/b direct targets IRAK1 and CARD10 resulted in reduced expression of SERPINB2, suggesting that miR-146a/b indirectly control SERPINB2 expression in the skin. The siRNA silencing of SERPINB2 increased the expression of IL-8, CXCL5 and CCL5 and migration of neutrophils revealing its anti-inflammatory role in keratinocytes. Our data together suggest that SERPINB2 and miR-146a/b are part of disease-related network of molecules that are coordinately regulated and act in controlling the inflammatory responses in psoriatic skin.

SerpinB2 inhibits migration and promotes a resolution phase signature in large peritoneal macrophages

SerpinB2 (plasminogen activator inhibitor type 2) has been called the "undecided serpin" with no clear consensus on its physiological role, although it is well described as an inhibitor of urokinase plasminogen activator (uPA). In macrophages, pro-inflammatory stimuli usually induce SerpinB2; however, expression is constitutive in Gata6+ large peritoneal macrophages (LPM). Interrogation of expression data from human macrophages treated with a range of stimuli using a new bioinformatics tool, CEMiTool, suggested that SerpinB2 is most tightly co- and counter-regulated with genes associated with cell movement. Using LPM from SerpinB2-/- and SerpinB2R380A (active site mutant) mice, we show that migration on Matrigel was faster than for their wild-type controls. Confocal microscopy illustrated that SerpinB2 and F-actin staining overlapped in focal adhesions and lamellipodia. Genes associated with migration and extracellular matrix interactions were also identified by RNA-Seq analysis of migrating RPM from wild-type and SerpinB2R380A mice. Subsequent gene set enrichment analyses (GSEA) suggested SerpinB2 counter-regulates many Gata6-regulated genes associated with migration. These data argue that the role of SerpinB2 in macrophages is inhibition of uPA-mediated plasmin generation during cell migration. GSEA also suggested that SerpinB2 expression (likely via ensuing modulation of uPA-receptor/integrin signaling) promotes the adoption of a resolution phase signature.

Screening differentially expressed proteins from co-cultured hematopoietic cells and bone marrow-derived stromal cells by quantitative proteomics (SILAC) method

Background

Bone marrow stromal cells protect hematopoietic cells and provide drug resistance by delivering bunch of variable proteins. Thus, alterations of protein expression are typically associated with cell–cell signal transduction and regulation of cellular functions.

Methods

Co-culture models of bone marrow stromal cells and hematopoietic cells are often used in studies of their crosstalk. Studies of altered protein expression initiated by stromal cell/hematopoietic cell interactions are an important new trend in microenvironmental research. There has been no report to date of global quantitative proteomics analysis of crosstalk between hematopoietic cells and stromal cells. In this study, we analyzed quantitative proteomes in a co-culture system of stromal HS5 cells and hematopoietic KG1a cells, and simultaneously tracked differentially expressed proteins in two types of cells before and after co-culture by stable isotope labeling by amino acids in cell culture (SILAC) method.

Results

We have shown that in co-cultured KG1a, 40 proteins (including CKAP4, LMNA, and SERPINB2) were upregulated and 64 proteins (including CD44, CD99, and NCAM1) were downregulated relative to KG1a alone. We utilized IPA analysis to discover that the NOD-like receptor signaling pathway was upregulated, whereas platelet activation was downregulated in co-cultured KG1a cells. Furthermore, 95 proteins (including LCP1, ARHGAP4, and UNCX) were upregulated and 209 proteins (including CAPG, FLNC, and MAP4) were downregulated in co-cultured HS5 relative to HS5 alone. The tight junction pathway was downregulated and glycolysis/gluconeogenesis pathway was dysfunctional in co-cultured HS5. Most importantly, the significantly differentially expressed proteins can also be confirmed using different co-cultured cell lines.

Conclusion

Altogether, we recommend such quantitative proteomics approach for the studies of the hematopoietic–stroma cross-talk, differentially expressed proteins and related signaling pathways identification. The differentially expressed proteins identified from this current SILAC method will provide a useful basis for ongoing studies of crosstalk between stromal cells and hematopoietic cells in co-culture systems. All these result suggested our ongoing studies can focus on the mechanisms underlying CKAP4 increase and CD44 decrease in co-cultured hematopoietic cells, and the increase of LCP1 and decrease of CAPG in co-cultured stromal cell. The proteomic profiles from the KG1a/stromal cell co-culture system give new molecular insights into the roles of these cells in MDS pathophysiology and related bone disease.

Electronic supplementary material

The online version of this article (10.1186/s12014-019-9249-x) contains supplementary material, which is available to authorized users.

The Kindlin2-p53-SerpinB2 signaling axis is required for cellular senescence in breast cancer

In cancer, cellular senescence is a complex process that leads to inhibition of proliferation of cells that may develop a neoplastic phenotype. A plethora of signaling pathways, when dysregulated, have been shown to elicit a senescence response. Two well-known tumor suppressor pathways, controlled by the p53 and retinoblastoma proteins, have been implicated in maintaining the cellular senescence phenotype. Kindlin-2, a member of an actin cytoskeleton organizing and integrin activator proteins, has been shown to play a key role in the regulation of several hallmarks of several cancers, including breast cancer (BC). The molecular mechanisms whereby Kindlin-2 regulates cellular senescence in BC tumors remains largely unknown. Here we show that Kindlin-2 regulates cellular senescence in part through its interaction with p53, whereby it regulates the expression of the p53-responsive genes; i.e., SerpinB2 and p21, during the induction of senescence. Our data show that knockout of Kindlin-2 via CRISPR/Cas9 in several BC cell lines significantly increases expression levels of both SerpinB2 and p21 resulting in the activation of hallmarks of cellular senescence. Mechanistically, interaction between Kindlin-2 and p53 at the promotor level is critical for the regulated expression of SerpinB2 and p21. These findings identify a previously unknown Kindlin-2/p53/SerpinB2 signaling axis that regulates cellular senescence and intervention in this axis may serve as a new therapeutic window for BCs treatment.

SERPINB2 overexpression inhibited cell proliferation, invasion and migration, led to G2/M arrest, and increased radiosensitivity in nasopharyngeal carcinoma cells

The aim of this study was to evaluate the effect of SERPINB2 on cell proliferation, cell cycle, epithelial-mesenchymal transition (EMT), invasion, migration, and radiosensitivity in nasopharyngeal carcinoma cells. Both CNE2R and CNE2 cells were transfected with pEGFP-N1-SERPINB2. Cell proliferation was measured by MTT assay, cell cycle by flow cytometry, and SERpINB2 expression by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was carried out to detect the protein expression. In addition, SERPINB2 and β-catenin were located intracellularly using an immunofluorescent assay, and cell migration and invasion were measured by wound healing and Transwell assays, respectively. Radiosensitivity was assessed using colony formation and MTT assays. SERPINB2 expression was downregulated in CNE2R cells. After transfection with pEGFP-N1-SERPINB2, the OD values were decreased, and there was an increased fraction in the G2/M phase. Moreover, SERPINB2 overexpression could inhibit the invasion and migration capabilities of CNE2R and CNE2 cells, with downregulation of vimentin, N-cadherin, nuclear β-catenin, matrix metalloproteinase (MMP)-2 and MMP-9, and upregulation of E-cadherin. Moreover, transfection with the SERPINB2 plasmid reduced the growth rate of CNE2R cells at doses of 2, 4 and 6 Gy, and also decreased the surviving fractions. Overexpression of SERPINB2 could reduce the proliferation, invasion and migration capabilities of CNE2R and CNE2 cells, and led to G2/M arrest via EMT inhibition, and this may be a potential strategy for enhancing the radiation sensitivity of nasopharyngeal carcinoma cells.

SerpinB2 is involved in cellular response upon UV irradiation

Ultraviolet light induced pyrimidine dimer is a helix distortion DNA damage type, which recruits repair complexes. However, proteins of these complexes that take part in both DNA damage recognition and repair have been well-described, the regulation of the downstream steps of nucleotide excision repair (NER) have not been clearly clarified yet. In a high-throughput screen, we identified SerpinB2 (SPB2) as one of the most dramatically upregulated gene in keratinocytes following UV irradiation. We found that both the mRNA and the protein levels of SPB2 were increased upon UV irradiation in various cell lines. Additionally, UV damage induced translocation of SPB2 from the cytoplasm to the nucleus as well as the damage induced foci formation of it. Here we show that SPB2 co-localizes with XPB involved in the NER pathway at UV-induced repair foci. Finally, we demonstrated that UV irradiation promoted the association of SPB2 with ubiquitylated proteins. In basal cell carcinoma tumour cells, we identified changes in the subcellular localization of SPB2. Based on our results, we conclude that SPB2 protein has a novel role in UV-induced NER pathway, since it regulates the removal of the repair complex from the damaged site leading to cancerous malformation.

Plasminogen activator inhibitor 2 (PAI2) inhibits invasive potential of hepatocellular carcinoma cells in vitro via uPA- and RB/E2F1-related mechanisms

BACKGROUND

Plasminogen activator inhibitor 2 (PAI2) has been shown to be associated with invasive phenotypes and prognosis in hepatocellular carcinoma (HCC). However, its biological roles and underlying mechanisms in invasion of HCC have not been explored. The present study aimed to address the issues.

METHODS

First, sub-lines in that PAI2 was stably overexpressed and silenced were established based on MHCC97H and BEL7402 cell lines, respectively. Wound-healing and transwell assays were applied to evaluate cell migration and invasion. Urokinase-type plasminogen activator (uPA) activity was measured using an ELISA kit. Real-time RT-PCR and western blotting were used to show gene expression at mRNA and protein levels. E2F1 expression in human specimens was determined by tissue microarray-based immunohistochemical staining.

RESULTS

The sub-lines, MHCC97H-PAI2 and BEL7402-siPAI2, were successfully established. The two sub-lines carried much lower and higher migration and invasion powers, respectively, in contrast to the controls. In MHCC97H-PAI2 sub-line, intra-medium uPA activity was significantly decreased, while RB expression was obviously elevated, compared with the controls. The BEL7402-siPAI2 sub-line presented the opposite trend. To identify the role of RB/E2F1 pathway, we transiently overexpressed E2F1 in MHCC97H-PAI2 sub-line, and largely reversed the inhibitory effects of PAI2 on cell migration and invasion, through regulating multiple matrix metalloproteinases and epithelial-mesenchymal transition. In HCC specimens, E2F1 expression was much higher in tumor than in non-tumor tissues, and was significantly related to Edmondson-Steiner grade, overall as well as tumor-free survival.

CONCLUSIONS

Our data suggest that PAI2 inhibits invasive potential of HCC cells via uPA- and RB/E2F1-related mechanisms.

SerpinB2 deficiency in mice reduces bleeding times via dysregulated platelet activation

SerpinB2, also known as plasminogen activation inhibitor type 2 (PAI-2), is classically viewed as an inhibitor of fibrinolysis. However, we show herein a distinct, hitherto unrecognized role for SerpinB2 in hemostasis. Mice deficient in SerpinB2 expression and mice with an active site mutation in SerpinB2, both showed significant reductions in tail bleeding times. This hemostatic phenotype was associated with platelets, with SerpinB2 and SerpinB2-urokinase complexes clearly present in platelet fractions, and immunohistochemistry of blood clots suggesting SerpinB2 is associated with platelet aggregates. Thromboelastography illustrated faster onset of clot formation in blood from SerpinB2 deficient mice, whereas clotting of platelet-free plasma was unaffected. The results appear consistent with the low circulating SerpinB2 levels and hypercoagulation seen during pre-eclampsia; however, SerpinB2 was not detected in human platelets.

Deciphering the role of ectosomes in cancer development and progression: focus on the proteome

Ectosomes are small heterogeneous membrane vesicles generated by budding from the plasma membrane in a variety of cell types and, more frequently, in tumor cells. They are shed into the extracellular space and are proposed as a novel form of intracellular communication in which information is transmitted from the originating cell to recipient cells without direct cell-to-cell contact. This review focuses on a single population of extracellular vesicles-ectosomes. We summarize recent studies of tumor-derived ectosomes which examine their biogenesis and protein cargo, and their influence on different aspects of cancer progression. We discuss possible clinical implications involving ectosomes as potential biomarkers, diagnostic tools and treatment targets in oncology. The unique composition of the molecules (cargo) that ectosomes carry, and their functional role, depends largely on the state of their originating cell. Through horizontal transfer of a variety of biologically active molecules (including proteins, lipids and nucleic acids) between donor and recipient cells, tumor-derived ectosomes may play functional roles in oncogenic transformation, tumor progression, invasion, metastasis, angiogenesis promotion, escape from immune surveillance, and drug resistance, thereby facilitating disease progression. The presence of tumor-derived ectosomes in body fluids such as the blood and urine of cancer patients makes them potentially useful prognostic and predictive biomarkers. Tumor-derived ectosomes also offer possible targets for multiple therapeutic strategies.

Relevance of the plasminogen system in physiology, pathology, and regeneration of oral tissues - From the perspective of dental specialties

Plasmin is a proteolytic enzyme that is crucial in fibrinolysis. In oral tissues, the plasminogen system plays an essential role in physiological and pathological processes, which in addition to fibrinolysis include degradation of extracellular matrix, inflammation, immune response, angiogenesis, tissue remodeling, cell migration, and wound healing. Oral tissues reveal a change in the plasminogen system during pathological processes such as periodontitis, peri-implantitis, or pulpitis, as well as in response to mechanical load. The plasminogen system is also a key element in tissue regeneration. The number of studies investigating the plasminogen system in dentistry have grown continuously in recent years, highlighting its increasing relevance in dental medicine. In this review, we present the diverse functions of the plasminogen system in physiology and its importance for dental specialists in pathology and regeneration. We thus provide an overview of the current knowledge on the role of the plasminogen system in the different fields of dentistry, including endodontics, orthodontics, periodontics, and oral surgery.

Down-regulation of SerpinB2 is associated with gefitinib resistance in non-small cell lung cancer and enhances invadopodia-like structure protrusions

The failure of targeted therapy due to the resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, is considered a major problem in the treatment of non-small cell lung cancer (NSCLC) patients. SerpinB2, a component of the urokinase plasminogen activator (uPA) system, has been recognized as a biomarker for the progression and metastasis of lung cancer. Nevertheless, the relationship between SerpinB2 and EGFR-TKI resistance has not been elucidated. Here, we report that SerpinB2 is down-regulated in gefitinib-resistant (H292-Gef) cells compared to gefitinib-sensitive (H292) cells. The low SerpinB2 levels in H292-Gef cells were also associated with an enhancement in invasiveness and increase in the length of invadopodia-like structures in the cells. The effect on invasiveness and gefitinib sensitivity was confirmed by knockdown and overexpression of SerpinB2. In addition, the possibility to overcome the resistance through the up-regulation of SerpinB2 was supported by employing an antitumor agent yuanhuadine (YD). Treatment with YD effectively elevated SerpinB2 levels and suppressed invasive properties in H292-Gef cells. Collectively, these findings demonstrate the prospective role of SerpinB2 as a novel biomarker for acquired gefitinib resistance and a potential target for NSCLC treatment.

Physico-chemical properties and biological effects of diesel and biomass particles

Diesel combustion and solid biomass burning are the major sources of ultrafine particles (UFP) in urbanized areas. Cardiovascular and pulmonary diseases, including lung cancer, are possible outcomes of combustion particles exposure, but differences in particles properties seem to influence their biological effects. Here the physico-chemical properties and biological effects of diesel and biomass particles, produced under controlled laboratory conditions, have been characterized. Diesel UFP were sampled from a Euro 4 light duty vehicle without DPF fuelled by commercial diesel and run over a chassis dyno. Biomass UFP were collected from a modern automatic 25 kW boiler propelled by prime quality spruce pellet. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of both diesel and biomass samples showed aggregates of soot particles, but in biomass samples ash particles were also present. Chemical characterization showed that metals and PAHs total content was higher in diesel samples compared to biomass ones. Human bronchial epithelial (HBEC3) cells were exposed to particles for up to 2 weeks. Changes in the expression of genes involved in xenobiotic metabolism were observed after exposure to both UFP already after 24 h. However, only diesel particles modulated the expression of genes involved in inflammation, oxidative stress and epithelial-to-mesenchymal transition (EMT), increased the release of inflammatory mediators and caused phenotypical alterations, mostly after two weeks of exposure. These results show that diesel UFP affected cellular processes involved in lung and cardiovascular diseases and cancer. Biomass particles exerted low biological activity compared to diesel UFP. This evidence emphasizes that the study of different emission sources contribution to ambient PM toxicity may have a fundamental role in the development of more effective strategies for air quality improvement.

SerpinB2 Deficiency Results in a Stratum Corneum Defect and Increased Sensitivity to Topically Applied Inflammatory Agents

SerpinB2 (plasminogen activator inhibitor type 2) is constitutively expressed at high levels by differentiating keratinocytes in mice and humans; however, the physiological function of keratinocyte SerpinB2 remains unclear. Herein, we show that SerpinB2(-/-) mice are more susceptible to contact dermatitis after topical application of dinitrofluorobenzene, and show enhanced inflammatory lesions after topical applications of phorbol ester. Untreated SerpinB2(-/-) mice showed no overt changes in epithelial structure, and we were unable to find evidence for a role for keratinocyte SerpinB2 in regulating immunity, apoptosis, IL-1β production, proteasomal activity, or wound healing. Instead, the phenotype was associated with impaired skin barrier function and a defective stratum corneum, with SerpinB2(-/-) mice showing increased transepidermal water loss, increased overt loss of stratum corneum in inflammatory lesions, and impaired stratum corneum thickening after phorbol ester treatment. Immunoblotting suggested that SerpinB2 (cross-linked into the cornified envelope) is present in the stratum corneum and retains the ability to form covalent inhibitory complexes with urokinase. Data suggest that the function of keratinocyte SerpinB2 is protection of the stratum corneum from proteolysis via inhibition of urokinase, thereby maintaining the integrity and barrier function of the stratum corneum, particularly during times of skin inflammation. Implications for studies involving genetically modified mice treated with topical agents and human dermatological conditions, such as contact dermatitis, are discussed.

Imaging of Angiotropism/Vascular Co-Option in a Murine Model of Brain Melanoma: Implications for Melanoma Progression along Extravascular Pathways

Angiotropism/pericytic mimicry and vascular co-option involve tumor cell interactions with the abluminal vascular surface. These two phenomena may be closely related. However, investigations of the two processes have developed in an independent fashion and different explanations offered as to their biological nature. Angiotropism describes the propensity of tumor cells to spread distantly via continuous migration along abluminal vascular surfaces, or extravascular migratory metastasis (EVMM). Vascular co-option has been proposed as an alternative mechanism by which tumors cells may gain access to a blood supply. We have used a murine brain melanoma model to analyze the interactions of GFP human melanoma cells injected into the mouse brain with red fluorescent lectin-labeled microvascular channels. Results have shown a striking spread of melanoma cells along preexisting microvascular channels and features of both vascular co-option and angiotropism/pericytic mimicry. This study has also documented the perivascular expression of Serpin B2 by angiotropic melanoma cells in the murine brain and in human melanoma brain metastases. Our findings suggest that vascular co-option and angiotropism/pericytic mimicry are closely related if not identical processes. Further studies are needed in order to establish whether EVMM is an alternative form of cancer metastasis in addition to intravascular cancer dissemination.

Acquirement of DNA copy number variations in non-small cell lung cancer metastasis to the brain

Brain metastasis is a major complication of non-small cell lung cancer (NSCLC) and leads to most of the mortality of this disease. However, the biological mechanisms and molecular features in brain metastasis of NSCLC are poorly understood. In the present study, we compared whole-genome copy number variations (CNVs) between a primary lung adenocarcinoma and secondary metastatic brain lesion from the same patient using array comparative genomic hybridization (aCGH). The number of CNV regions was markedly higher in the secondary metastatic tumor than the primary tumor in the lung. In detail, the common CNVs in both tumors included gains of 7p22, 7p12-p11, 7q11, 7q22, 21q22, and 19q13; gains of 1p33-p34, 1q22, 5p13 and 14q11 whereas losses of 3p, 4q31, 5q, 11p15, Xp21-p22 and Xq21 were identified only in the secondary lesion. Gene Ontology enrichment analysis revealed that the genes with amplified copy numbers in both tumors were related to such processes as DNA replication and mismatch repair. Genes only amplified in the metastatic tumor were enriched in processes that include leukocyte migration and organ development, and genes with a lower copy number in the secondary tumor included the processes of proteolysis regulation, negative regulation of cell proliferation and cell adhesion. These findings provided new insight into the genomic mechanism of the spread of lung adenocarcinoma to the brain, and the candidate genes identified serve as novel indicators or putative targets in NSCLC brain metastasis.

Plasminogen Activator Inhibitor-2 Plays a Leading Prognostic Role among Protease Families in Non-Small Cell Lung Cancer

Background

In lung cancer, uPA, its receptor (uPAR), and the inhibitors PAI-1 and PAI-2 of the plasminogen activator family interact with MMP-2 and MMP-9 of the MMP family to promote cancer progression. However, it remains undetermined which of these markers plays the most important role and may be the most useful indicator to stratify the patients by risk.

Methods

We determined the individual prognostic value of these 6 markers by analyzing a derivation cohort with 98 non-small cell lung cancer patients by immunohistochemical staining. The correlation between the IHC expression levels of these markers and disease prognosis was investigated, and an immunohistochemical panel for prognostic prediction was subsequently generated through prognostic model analysis. The value of the immunohistochemical panel was then verified by a validation cohort with 91 lung cancer patients.

Results

In derivation cohort, PAI-2 is the most powerful prognostic factor (HR = 2.30; P = 0.001), followed by MMP-9 (HR = 2.09; P = 0.019) according to multivariate analysis. When combining PAI-2 and MMP-9, the most unfavorable prognostic group (low PAI-2 and high MMP-9 IHC expression levels) showed a 6.40-fold increased risk of a poor prognosis compared to the most favorable prognostic group (high PAI-2 and low MMP-9 IHC expression levels). PAI-2 and MMP-9 IHC panel could more precisely identify high risk patients in both derivation and validation cohort.

Conclusions

We revealed PAI-2 as the most powerful prognostic marker among PA and MMP protease family even after considering their close relationships with each other. By utilizing a combination of PAI-2 and MMP-9, more precise prognostic information than merely using pathological stage alone can be obtained for lung cancer patients.

SerpinB2 (PAI-2) Modulates Proteostasis via Binding Misfolded Proteins and Promotion of Cytoprotective Inclusion Formation

SerpinB2 (PAI-2), a member of the clade B family of serine protease inhibitors, is one of the most upregulated proteins following cellular stress. Originally described as an inhibitor of urokinase plasminogen activator, its predominant cytoplasmic localisation suggests an intracellular function. SerpinB2 has been reported to display cytoprotective properties in neurons and to interact with intracellular proteins including components of the ubiquitin-proteasome system (UPS). In the current study we explored the potential role of SerpinB2 as a modulator of proteotoxic stress. Initially, we transiently transfected wild-type SerpinB2 and SerpinB2-/- murine embryonic fibroblasts (MEFs) with Huntingtin exon1-polyglutamine (fused C-terminally to mCherry). Inclusion body formation as result of Huntingtin aggregation was evident in the SerpinB2 expressing cells but significantly impaired in the SerpinB2-/- cells, the latter concomitant with loss in cell viability. Importantly, recovery of the wild-type phenotype and cell viability was rescued by retroviral transduction of SerpinB2 expression. SerpinB2 modestly attenuated Huntingtin and amyloid beta fibril formation in vitro and was able to bind preferentially to misfolded proteins. Given the modest chaperone-like activity of SerpinB2 we tested the ability of SerpinB2 to modulate UPS and autophagy activity using a GFP reporter system and autophagy reporter, respectively. Activity of the UPS was reduced and autophagy was dysregulated in SerpinB2-/- compared to wild-type MEFs. Moreover, we observed a non-covalent interaction between ubiquitin and SerpinB2 in cells using GFP-pulldown assays and bimolecular fluorescence complementation. We conclude that SerpinB2 plays an important role in proteostasis as its loss leads to a proteotoxic phenotype associated with an inability to compartmentalize aggregating proteins and a reduced capacity of the UPS.

Dual-specificity phosphatase 5 regulates nuclear ERK activity and suppresses skin cancer by inhibiting mutant Harvey-Ras (HRasQ61L)-driven SerpinB2 expression

Ectopic expression of dual-specificity phosphatase 5 (DUSP5), an inducible mitogen-activated protein (MAP) kinase phosphatase, specifically inactivates and anchors extracellular signal-regulated kinase (ERK)1/2 in the nucleus. However, the role of endogenous DUSP5 in regulating the outcome of Ras/ERK kinase signaling under normal and pathological conditions is unknown. Here we report that mice lacking DUSP5 show a greatly increased sensitivity to mutant Harvey-Ras (HRas(Q61L))-driven papilloma formation in the 7,12-Dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA) model of skin carcinogenesis. Furthermore, mouse embryo fibroblasts (MEFs) from DUSP5(-/-) mice show increased levels of nuclear phospho-ERK immediately after TPA stimulation and fail to accumulate total ERK in the nucleus compared with DUSP5(+/+) cells. Surprisingly, a microarray analysis reveals that only a small number of Ras/ERK-dependent TPA-responsive transcripts are up-regulated on deletion of DUSP5 in MEFs and mouse skin. The most up-regulated gene on DUSP5 loss encodes SerpinB2, an inhibitor of extracellular urokinase plasminogen activator and deletion of DUSP5 acts synergistically with mutant HRas(Q61L) and TPA to activate ERK-dependent SerpinB2 expression at the transcriptional level. SerpinB2 has previously been implicated as a mediator of DMBA/TPA-induced skin carcinogenesis. By analyzing DUSP5(-/-), SerpinB2(-/-) double knockout mice, we demonstrate that deletion of SerpinB2 abrogates the increased sensitivity to papilloma formation seen on DUSP5 deletion. We conclude that DUSP5 performs a key nonredundant role in regulating nuclear ERK activation, localization, and gene expression. Furthermore, our results suggest an in vivo role for DUSP5 as a tumor suppressor by modulating the oncogenic potential of activated Ras in the epidermis.

uPA/PAI system, cathepsin B and hepatocellular carcinoma

Urokinase-type plasminogen activator and plasminogen activator inhibitor (uPA/PAI) are a pair of proteolytic enzyme activator/activator inhibitor. Cathepsin B is a lysosomal cysteine protease. It has been proved that cathepsin B can activate uPA. uPA/PAI and cathepsin B are closely related to the invasion, migration and tumor angiogenesis of malignant neoplasms. The uPA/PAI system and cathepsin B play an important role in the occurrence and development of liver cancer.