Secretory leukocyte peptidase inhibitor and lung cancer

The secretory leukocyte protease inhibitor (SLPI) in pathophysiology of non-communicable diseases: Evidence from experimental studies to clinical applications

Non-communicable diseases (NCDs) are a worldwide health issue because of their prevalence, negative impacts on human welfare, and economic costs. Protease enzymes play important roles in viral and NCD diseases. Slowing disease progression by inhibiting proteases using small-molecule inhibitors or endogenous inhibitory peptides appears to be crucial. Secretory leukocyte protease inhibitor (SLPI), an inflammatory serine protease inhibitor, maintains protease/antiprotease balance. SLPI is produced by host defense effector cells during inflammation to prevent proteolytic enzyme-induced tissue damage. The etiology of noncommunicable illnesses is linked to SLPI's immunomodulatory and tissue regeneration roles. Disease phases are associated with SLPI levels and activity changes in regional tissue and circulation. SLPI has been extensively evaluated in inflammation, but rarely in NCDs. Unfortunately, the thorough evaluation of SLPI's pathophysiological functions in NCDs in multiple research models has not been published elsewhere. In this review, data from PubMed from 2014 to 2023 was collected, analysed, and categorized into in vitro, in vivo, and clinical studies. According to the review, serine protease inhibitor (SLPI) activity control is linked to non-communicable diseases (NCDs) and other illnesses. Overexpression of the SLPI gene and protein may be a viable diagnostic and therapeutic target for non-communicable diseases (NCDs). SLPI is also cytoprotective, making it a unique treatment. These findings suggest that future research should focus on these pathways using advanced methods, reliable biomarkers, and therapy approaches to assess susceptibility and illness progression. Implications from this review will help pave the way for a new therapeutic target and diagnosis marker for non-communicable diseases.

Secretory leukocyte protease inhibitor (SLPI) in cancer pathophysiology: Mechanisms of action and clinical implications

Cancer is a multifaceted disorder frequently linked to the dysregulation of several biological processes. The SLPI is a multifunctional protein involved in the modulation of immunological response and the inhibition of protease activities. SLPI acts as an inhibitor of proteases, exerts antibacterial properties, and suppresses the transcription of proinflammatory genes through the nuclear factor-kappa B (NF-κB) pathway. The role of this protein as a regulatory agent has been implicated in various types of cancer. Recent research has revealed that SLPI upregulation in cancer cells enhances the metastatic capacity of epithelial malignancies, indicating the deleterious effects of this protein. Furthermore, SLPI interacts intricately with other cancer-promoting factors, including matrix metalloproteinase-2 (MMP-2), MMP-9, the NF-κB and Akt pathways, and the p53-upregulated modulator of apoptosis (PUMA). This review provides an overview of the role of SLPI in cancer pathophysiology, emphasizing its expression in cancer cells and tissues, its potential as a prognostic biomarker, and its therapeutic promise as a target in cancer treatment. The mechanisms of SLPI action in cancer, including its anti-inflammatory effects, regulation of cell proliferation and angiogenesis, and modulation of the tumor microenvironment, have been investigated. The clinical implications of SLPI in cancer have been discussed, including its potential as a diagnostic and prognostic biomarker, its role in chemoresistance, and its therapeutic potential in several types of cancer, such as hepatocellular carcinoma (HCC), colorectal cancer (CRC), pancreatic cancer, head and neck squamous cell carcinoma (HNSCC), ovarian cancer (OvCa), prostate cancer (PC), gastric cancer (GC), breast cancer, and other cancers. In addition, we emphasized the significance of SLPI in cancer, which offers fresh perspectives on potential targets for cancer therapy.

Inhibition of secretory leukocyte protease inhibitor (SLPI) promotes the PUMA-mediated apoptosis and chemosensitivity to cisplatin in colorectal cancer cells

BACKGROUND

Aberrant expression of Secretory Leukocyte Protease Inhibitor (SLPI) has been associated with human cancer growth and its suppression was identified as a potential target for anti-cancer drugs, particularly in colorectal cancer. However, the underlying mechanism by which SLPI affected the development of drug resistance in CRC remains unclear.

OBJECTIVE

This study investigated the role of SLPI in the p53-up-regulated modulator of apoptosis (PUMA)-mediated CRC cells' apoptosis and their chemosensitivity to Cisplatin.

METHODS

A series of qRT-PCR and western blot analyses were performed to characterize the expressions of SLPI, PUMA, and Akt in CRC lines. Tunel, transwell, and CCK-8 analyses were monitored to define the impacts of the siRNA-mediated knockdown of SLPI on CRC cell development. Furthermore, in vivo development of CRC was evaluated in nude mice infected with siSLPI or Cisplatin alone or both, and Ki67 and caspase-3 immunohistochemistry assay was monitored on multiple tissue microarray from the same cohort.

RESULTS

Our results showed that SLPI inhibition strongly promoted the expressions of the pro-apoptotic protein PUMA, cleaved-caspase3 and Bax and reduced the cell viability of HT29 and HT116 cell lines in vitro. In addition, siSLPI knockdown effectively suppressed both Akt and FoxO3 proteins and improved the sensitivity to cisplatin chemotherapy. Xenograft tumor assay revealed a lowered growth in mice treated with Cisplatin, while combined treatment of siSLPI achieved more significant anticancer effects than Cisplatin alone.

CONCLUSIONS

Taken together, these findings demonstrated that suppression of SLPI might repress the growth of human colorectal cancer cells both in vitro and in vivo. These results suggested SLPI as a novel resistance factor to Cisplatin, and a combination of Cisplatin and SLPI inhibitor be beneficial for colorectal cancer therapy.

Up-regulation of secretory leukocyte protease inhibitor in human samples might have a potential role of predicting prostate cancer recurrence and progression after surgery and hormonal therapy

Using new castration-resistant prostate cancer (CRPC) cell lines developed from LNCaP cells as a model for CRPC, we searched for novel biomarkers by analyzing the proteins secreted in culture supernatants. The results showed that the levels of secretory leukocyte protease inhibitor (SLPI) in these cell lines were 4.7-6.7 times higher than those secreted in parental LNCaP. Patients with localized prostate cancer (PC) and who expressed SLPI had a significantly lower prostate-specific antigen (PSA) progression-free survival rate than those who did not. Multivariate analysis revealed that SLPI expression was an independent risk factor for PSA recurrence. By contrast, when immunostaining of SLPI was performed on consecutive prostate tissue samples obtained from 11 patients, both in hormone naive (HN) and castration resistant (CR) conditions, only one patient expressed SLPI in the HNPC state; however, four of the 11 patients expressed SLPI in the CRPC state. In addition, two of these four patients were resistant to enzalutamide, and there was a discrepancy between their serum PSA levels and radiographic progression of the disease. These results suggest that SLPI can be a predictor of prognosis in patients with localized PC and disease progression in CRPC patients.

FAPhigh α-SMAlow cancer-associated fibroblast-derived SLPI protein encapsulated in extracellular vesicles promotes ovarian cancer development via activation of PI3K/AKT and downstream signaling pathways

Ovarian cancer is the most lethal gynecological malignancy worldwide with high metastasis and poor prognosis rates. Cancer‐associated fibroblasts (CAFs), a heterogeneous population of cells that constitutes a major component of the tumor microenvironment, secrete extracellular vesicles (EVs) loading with proteins, lipids, and RNAs to promote tumorigenesis. However, the specific roles of CAF‐derived proteins contained in EVs in ovarian cancer remain poorly understood at present. Using the gene expression microarray analysis, we identified a list of dysregulated genes between the α‐SMA⁺CAF and FAP⁺CAF subpopulations, from which secretory leukocyte protease inhibitor (SLPI) was chosen for further validation. Quantitative PCR, western blot, immunohistochemistry, and enzyme‐linked immunosorbent assays were used to assess SLPI expression in ovarian cancer cells, tissues, CAFs, and EVs. Additionally, we evaluated the effects of exogenous SLPI on proliferation, migration, invasion, and adhesion of ovarian cancer cells in vitro. Our results showed SLPI protein was upregulated in CAFs, particularly in the FAP^highα‐SMA^lowCAF subpopulation, and associated with increased tumor grade and decreased overall survival (OS). Importantly, CAF‐derived SLPI protein could be encapsulated in EVs for delivery to ovarian cancer cells, thus facilitating cell proliferation, migration, invasion, and adhesion via activating the PI3K/AKT and downstream signaling pathways. Moreover, high plasma expression of SLPI encapsulated in EVs was closely correlated with tumor stage in ovarian cancer patients. Our collective results highlight an oncogenic role of plasma EV‐encapsulated SLPI secreted by CAFs in tumor progression for the first time, supporting its potential utility as a prognostic biomarker of ovarian cancer.

SLPI suppresses hepatocellular carcinoma progression via endoplasmic reticulum stress induced apoptosis

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Secretory leukocyte protease inhibitor (SLPI) has been reported to function as a regulatory factor in several cancers. However, its biological functions and underlying mechanisms in HCC remain to be uncovered. Here, we aimed to explore the effect of SLPI in HCC. In our study, we found that the mRNA and protein expression levels of SLPI were significantly down-regulated in HCC tissues and hepatoma cell lines and low level of SLPI predicted worse survival in our HCC cohorts. In term of function, silencing of SLPI markedly promoted whereas overexpression SLPI suppressed proliferation, migration and invasion capabilities of HCC cells in vitro, and ectopic expression of SLPI inhibited the tumorigenicity of HCC cells in vivo. Mechanistic studies demonstrated that SLPI played a protective role in HCC progression via activating endoplasmic reticulum stress (ER stress)-mediated apoptosis of hepatoma cells, which could be regulated by MAPK signaling pathways. In summary, our findings highlight that SLPI could serve as a potential prognostic biomarker and putative tumor suppressor by enhancing ER stress-induced apoptosis in HCC cells mediated by MAPK signaling pathways, which provides new insights into promising therapeutic targets for HCC treatment.

SLPI facilitates cell migration by regulating lamellipodia/ruffles and desmosomes, in which Galectin4 plays an important role

To elucidate the underlying mechanism of secretory leukocyte protease inhibitor (SLPI)-induced cell migration, we compared SLPI-deleted human gingival carcinoma Ca9-22 (ΔSLPI) cells and original (wild-type: wt) Ca9-22 cells using several microscopic imaging methods and gene expression analysis. Our results indicated reduced migration of ΔSLPI cells compared to wtCa9-22 cells. The lamellipodia/dorsal ruffles were smaller and moved slower in ΔSLPI cells compared to wtCa9-22 cells. Furthermore, well-developed intermediate filament bundles were observed at the desmosome junction of ΔSLPI cells. In addition, Galectin4 was strongly expressed in ΔSLPI cells, and its forced expression suppressed migration of wtCa9-22 cells. Taken together, SLPI facilitates cell migration by regulating lamellipodia/ruffles and desmosomes, in which Galectin4 plays an important role.

HE4 Overexpression by Ovarian Cancer Promotes a Suppressive Tumor Immune Microenvironment and Enhanced Tumor and Macrophage PD-L1 Expression

Ovarian cancer is a highly fatal malignancy characterized by early chemotherapy responsiveness but the eventual development of resistance. Immune targeting therapies are changing treatment paradigms for numerous cancer types but have had minimal success in ovarian cancer. Through retrospective patient sample analysis, we have determined that high human epididymis protein 4 (HE4) production correlates with multiple markers of immune suppression in ovarian cancer, including lower CD8⁺ T cell infiltration, higher PD-L1 expression, and an increase in the peripheral monocyte to lymphocyte ratio. To further understand the impact that HE4 has on the immune microenvironment in ovarian cancer, we injected rats with syngeneic HE4 high- and low-expressing cancer cells and analyzed the differences in their tumor and ascites immune milieu. We found that high tumoral HE4 expression promotes an ascites cytokine profile that is rich in myeloid-recruiting and differentiation factors, with an influx of M2 macrophages and increased arginase 1 production. Additionally, CTL activation is significantly reduced in the ascites fluid, and there is a trend toward lower CTL infiltration of the tumor, whereas NK cell recruitment to the ascites and tumor is also reduced. PD-L1 expression by tumor cells and macrophages is increased by HE4 through a novel posttranscriptional mechanism. Our data have identified HE4 as a mediator of tumor-immune suppression in ovarian cancer, highlighting this molecule as a potential therapeutic target for the treatment of this devastating disease.

Targeting secretory leukocyte protease inhibitor (SLPI) inhibits colorectal cancer cell growth, migration and invasion via downregulation of AKT

The secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor which plays important role in bacterial infection, inflammation, wound healing and epithelial proliferation. Dysregulation of SLPI has been reported in a variety of human cancers including glioblastoma, lung, breast, ovarian and colorectal carcinomas and is associated with tumor aggressiveness and metastatic potential. However, the pathogenic role of SLPI in colorectal cancer is still unclear. Here we showed that SLPI mRNA level was significantly upregulated in colorectal cancer tissues compared to adjacent normal controls. Targeting SLPI by siRNA inhibited proliferation, migration and invasion of colorectal cancer cells lines HT29 and HT116 in vitro. Mechanistically, blockage of cancer cell growth and metastasis after SLPI knockdown was associated with down-regulation of AKT signaling. In conclusion, SLPI regulated colorectal cell growth and metastasis via AKT signaling. SLPI may be a novel biomarker and therapeutic target for colorectal cancer. Targeting AKT signaling may be effective for colorectal cancer treatment.

Androgen receptor suppresses prostate cancer metastasis but promotes bladder cancer metastasis via differentially altering miRNA525-5p/SLPI-mediated vasculogenic mimicry formation

Early studies suggest that the androgen receptor (AR) may play differential roles in influencing prostate cancer (PCa) and bladder cancer (BCa) metastasis, but the underlying mechanisms remain unclear. Here, we found that the AR might function via differentially altering vasculogenic mimicry (VM) formation to either decrease PCa metastasis or increase BCa metastasis. Mechanism dissection showed that the AR could differentially alter the expression of the VM marker SLPI through miR-525-5p to regulate SLPI; moreover, it could either increase miR-525-5p transcription in PCa or decrease it in BCa via binding to different androgen-response-elements (AREs) located at different positions in the miR-525 precursor promoter. Further, results from liquid chromatography-mass spectrometry (LC-MS) showed that the co-factors of AR in PCa and BCa are NFIX and HDAC2, respectively. Together, these results provide the first detailed mechanism of how the AR can differentially alter PCa and BCa metastasis; thus, targeting the newly identified AR-miR-525-5p-SLPI axis may help suppress metastasis.

SLPI Inhibits ATP-Mediated Maturation of IL-1β in Human Monocytic Leukocytes: A Novel Function of an Old Player

Interleukin-1β (IL-1β) is a potent, pro-inflammatory cytokine of the innate immune system that plays an essential role in host defense against infection. However, elevated circulating levels of IL-1β can cause life-threatening systemic inflammation. Hence, mechanisms controlling IL-1β maturation and release are of outstanding clinical interest. Secretory leukocyte protease inhibitor (SLPI), in addition to its well-described anti-protease function, controls the expression of several pro-inflammatory cytokines on the transcriptional level. In the present study, we tested the potential involvement of SLPI in the control of ATP-induced, inflammasome-dependent IL-1β maturation and release. We demonstrated that SLPI dose-dependently inhibits the ATP-mediated inflammasome activation and IL-1β release in human monocytic cells, without affecting the induction of pro-IL-1β mRNA by LPS. In contrast, the ATP-independent IL-1β release induced by the pore forming bacterial toxin nigericin is not impaired, and SLPI does not directly modulate the ion channel function of the human P2X₇ receptor heterologously expressed in Xenopus laevis oocytes. In human monocytic U937 cells, however, SLPI efficiently inhibits ATP-induced ion-currents. Using specific inhibitors and siRNA, we demonstrate that SLPI activates the calcium-independent phospholipase A2β (iPLA2β) and leads to the release of a low molecular mass factor that mediates the inhibition of IL-1β release. Signaling involves nicotinic acetylcholine receptor subunits α7, α9, α10, and Src kinase activation and results in an inhibition of ATP-induced caspase-1 activation. In conclusion, we propose a novel anti-inflammatory mechanism induced by SLPI, which inhibits the ATP-dependent maturation and secretion of IL-1β. This novel signaling pathway might lead to development of therapies that are urgently needed for the prevention and treatment of systemic inflammation.

The DNA methylation profile of liver tumors in C3H mice and identification of differentially methylated regions involved in the regulation of tumorigenic genes

Background

C3H mice have been frequently used in cancer studies as animal models of spontaneous liver tumors and chemically induced hepatocellular carcinoma (HCC). Epigenetic modifications, including DNA methylation, are among pivotal control mechanisms of gene expression leading to carcinogenesis. Although information on somatic mutations in liver tumors of C3H mice is available, epigenetic aspects are yet to be clarified.

Methods

We performed next generation sequencing-based analysis of DNA methylation and microarray analysis of gene expression to explore genes regulated by DNA methylation in spontaneous liver tumors of C3H mice. Overlaying these data, we selected cancer-related genes whose expressions are inversely correlated with DNA methylation levels in the associated differentially methylated regions (DMRs) located around transcription start sites (TSSs) (promoter DMRs). We further assessed mutuality of the selected genes for expression and DNA methylation in human HCC using the Cancer Genome Atlas (TCGA) database.

Results

We obtained data on genome-wide DNA methylation profiles in the normal and tumor livers of C3H mice. We identified promoter DMRs of genes which are reported to be related to cancer and whose expressions are inversely correlated with the DNA methylation, including Mst1r, Slpi and Extl1. The association between DNA methylation and gene expression was confirmed using a DNA methylation inhibitor 5-aza-2′-deoxycytidine (5-aza-dC) in Hepa1c1c7 cells and Hepa1-6 cells. Overexpression of Mst1r in Hepa1c1c7 cells illuminated a novel downstream pathway via IL-33 upregulation. Database search indicated that gene expressions of Mst1r and Slpi are upregulated and the TSS upstream regions are hypomethylated also in human HCC. These results suggest that DMRs, including those of Mst1r and Slpi, are involved in liver tumorigenesis in C3H mice, and also possibly in human HCC.

Conclusions

Our study clarified genome wide DNA methylation landscape of C3H mice. The data provide useful information for further epigenetic studies of mice models of HCC. The present study particularly proposed novel DNA methylation-regulated pathways for Mst1r and Slpi, which may be applied not only to mouse HCC but also to human HCC.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4221-0) contains supplementary material, which is available to authorized users.

Effect of Pingchuan Guben decoction on patients with chronic obstructive pulmonary disease: Results from a randomized comparative effectiveness research trial

Chronic obstructive pulmonary disease (COPD) is known to be a systemic low-grade ongoing inflammation exerting major health and economic burden worldwide. Complementary and alternative medicines, such as Traditional Chinese Medicine, are widely used for the treatment of patients with COPD. The present study was designed to investigate the efficacy of Pingchuan Guben decoction on patients with COPD through a double-blinded, open-labeled, randomized controlled trial. A total of 86 patients were randomly assigned to two groups, with 43 patients in the intervention group and 43 cases in the control group. The patients in the control group were treated with conventional western medicine, and the intervention group received a combination of conventional western medicine and Pingchuan Guben decoction. After 12 weeks of treatment, the mean 6-minute walking distance, forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC) and FEV1/FVC in the intervention group were significantly higher than those of the control group (P<0.05). The levels of inflammation factors and protease molecules were significantly ameliorated in the intervention group compared with the control group (P<0.05). The levels of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor-E2-related factor-2 (Nrf2), superoxide anions, malondialdehyde, glutathione S-transferase and glutathione peroxidase were significantly more improved in the intervention group compared with those in the control group over the 12-week study period (P<0.05). Therefore, combinations of western medicine with Pingchuan Guben decoction may exert therapeutic effects on patients with COPD via modulations of inflammation factors and protease molecules, as well as the activation of the Keap1/Nrf2 signaling pathway.

WAP four-disulfide core domain protein 2 promotes metastasis of human ovarian cancer by regulation of metastasis-associated genes

BACKGROUND

WAP four-disulfide core domain protein 2 (WFDC2) shows a tumor-restricted upregulated pattern of expression in ovarian cancer.

METHODS

In this study, we evaluated the role of WFCD2 in tumor mobility, invasion and metastasis of ovarian cancer in clinical tissue and in ovarian cancer cells, both in vitro and in vivo.

RESULTS

Our results revealed WFCD2 was overexpressed in ovarian tissues, and the expression level of WFCD2 was associated with metastasis and lymph node metastasis. Higher expression of WFCD2 was also observed in aggressive HO8910-PM cells than in HO8910 cells, and WFCD2 knockdown halted cell migration, invasion, tumorigenicity and metastasis in ovarian cancer cells, both in vitro and in vivo. Knockdown of WFDC2 induced the down-regulation of ICAM-1, CD44, and MMP2.

CONCLUSION

In summary, our work demonstrates that WFCD2 promotes metastasis in ovarian cancer. These findings suggest that WFCD2 plays a critical role in promoting metastasis and may constitute a potential therapeutic target of ovarian cancer.

Elevated Concentrations of SERPINE2/Protease Nexin-1 and Secretory Leukocyte Protease Inhibitor in the Serum of Patients with Papillary Thyroid Cancer

Introduction. SERPINE2 and secretory leukocyte protease inhibitor (SLPI) are proteins with anticoagulant properties which could promote solid tumor growth. However, their role in the pathogenesis of thyroid cancer has not been determined. Materials and Methods. The aim of this study was to assess serum SERPINE2 and SLPI concentrations in a group of 36 patients with papillary thyroid cancer (PTC) and a group of 19 subjects with multinodular nontoxic goiter (MNG). The control group (CG) consisted of 20 healthy volunteers. Blood samples were collected one day before surgery. Serum SERPINE2 and SLPI concentrations were measured using specific ELISA methods. Results. Significantly higher concentrations of SERPINE2 and SLPI were found in patients with PTC as compared with MNG and controls. Positive correlation was found between SERPINE2 and SLPI concentrations in PTC patients. The levels of SERPINE2 and SLPI did not differ significantly between MNG and healthy controls. Conclusions. Our results indicate that SERPINE2 and SLPI play a significant role in the development of papillary thyroid cancer and imply that the evaluation of serum concentrations of both anticoagulant molecules may be considered as additional marker for the differentiation of malignancies during the preoperative diagnosis of patients with thyroid gland tumors.

Antitumor Efficacy of SLPI Promoter-Controlled Expression of Artificial microRNA Targeting EGFR in a Squamous Cell Carcinoma Cell Line

The purpose of this study was to develop a recombinant adenovirus with secretory leukoprotease inhibitor (SLPI) promoter-controlled expression for gene therapy of squamous cell carcinoma (SCC). An artificial microRNA targeting epidermal growth factor receptor (EGFR) was designed, and used to construct a replication-defective recombinant adenovirus with SLPI promoter-controlled expression. The silencing efficiency of this vector (Ad-SLPI-EGFRamiR) was detected in Hep-2 cells. Western blotting showed that the expression of 170 kD EGFR was significantly reduced in Hep-2 cells 72 h after infection with Ad-SLPI-EGFRamiR. At a multiplicity of infection (MOI) of 200 pfu/cell, proliferation of Hep-2 cells was highly inhibited by Ad-SLPI-EGFRamiR (inhibition rate: ~70%). The apoptosis rate of Hep-2 cells at 72 h after infection with Ad-SLPI-EGFRamiR at a MOI 35 pfu/cell was 32.8%. The adenovirus constructed was able to specifically inhibit the growth of SCC cells in vitro.

TLR ligands, but not modulators of histone modifiers, can induce the complex immune response pattern of endotoxin tolerance in mammary epithelial cells

Excessive stimulation of the TLR4 axis through LPS reduces the expression of some cytokine genes in immune cells, while stimulating the expression of immune defense genes during a subsequent bacterial infection. This endotoxin tolerance (ET) is mediated via epigenetic mechanisms. Priming the udder of cows with LPS was shown to induce ET in mammary epithelial cells (MEC), thereby protecting the udder against reinfection for some time. Seeking alternatives to LPS priming we tried to elicit ET by priming MEC with either lipopeptide (Pam2CSK4) via the TLR2/6 axis or inhibitors of histone-modifying enzymes. Pre-incubation of MEC with Pam2CSK4 enhanced baseline and induced expression of bactericidal (β-defensin; SLPI) and membrane protecting factors (SAA3, TGM3), while reducing the expression of cytokine- and chemokine-encoding genes (TNF, IL1β) after a subsequent pathogen challenge, the latter, however, not as efficiently as after LPS priming. Pre-treating MEC with various inhibitors of histone H3 modifiers (for demethylation, acetylation or deacetylation) all failed to induce any of the protective factors and only resulted in some dampening of cytokine gene expression after the re-challenge. Hence, triggering immune functions via the TLR axis, but not through those histone modifiers, induced the beneficial phenomenon of ET in MEC.

Blood-based lung cancer biomarkers identified through proteomic discovery in cancer tissues, cell lines and conditioned medium

Background

Support for early detection of lung cancer has emerged from the National Lung Screening Trial (NLST), in which low-dose computed tomography (LDCT) screening reduced lung cancer mortality by 20 % relative to chest x-ray. The US Preventive Services Task Force (USPSTF) recently recommended annual screening for the high-risk population, concluding that the benefits (life years gained) outweighed harms (false positive findings, abortive biopsy/surgery, radiation exposure). In making their recommendation, the USPSTF noted that the moderate net benefit of screening was dependent on the resolution of most false-positive results without invasive procedures. Circulating biomarkers may serve as a valuable adjunctive tool to imaging.

Results

We developed a broad-based proteomics discovery program, integrating liquid chromatography/mass spectrometry (LC/MS) analyses of freshly resected lung tumor specimens (n = 13), lung cancer cell lines (n = 17), and conditioned media collected from tumor cell lines (n = 7). To enrich for biomarkers likely to be found at elevated levels in the peripheral circulation of lung cancer patients, proteins were prioritized based on predicted subcellular localization (secreted, cell-membrane associated) and differential expression in disease samples. 179 candidate biomarkers were identified. Several markers selected for further validation showed elevated levels in serum collected from subjects with stage I NSCLC (n = 94), relative to healthy smoker controls (n = 189). An 8-marker model was developed (TFPI, MDK, OPN, MMP2, TIMP1, CEA, CYFRA 21–1, SCC) which accurately distinguished subjects with lung cancer (n = 50) from high risk smokers (n = 50) in an independent validation study (AUC = 0.775).

Conclusions

Integrating biomarker discovery from multiple sample types (fresh tissue, cell lines and conditioned medium) has resulted in a diverse repertoire of candidate biomarkers. This unique collection of biomarkers may have clinical utility in lung cancer detection and diagnoses.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9090-9) contains supplementary material, which is available to authorized users.

SLPI knockdown induced pancreatic ductal adenocarcinoma cells proliferation and invasion

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease and still continues to have the worst prognosis of all gastrointestinal malignancies. Reports have demonstrated that secretory leukocyte protease inhibitor (SLPI) is overexpressed in various cancers and may be a potential therapeutic strategy for the treatment of different cancers. However, the possible role of SLPI in PDAC is still unknown. In the present study, we investigate the effects of SLPI gene knockdown on the biological behavior of human pancreatic cancer cells. The expressions of SLPI were detected, by qRT-PCR and Western blot, in human PDAC tissues as well as AsPC-1, BxPC-3 and PANC-1 cells. After transfection with siRNA targeting to SLPI, SLPI expression was detected by qRT-PCR and Western blot in cells. Cell proliferation and apoptosis were also evaluated by MTT assay and flow cytometry (FCM). The trans-well assays were also employed to explore the effects of SLPI knockdown on the migration and invasion of PDAC cells in vitro.

RESULTS

The expressions of SLPI derived from human PDAC and PDAC cell lines were significant higher than those of control groups, respectively (P < 0.05). Regression analysis showed elevated SLPI level was positive correlated with development of PDAC. The siRNA target to SLPI significantly decreased the expressions of SLPI in these PDAC cell lines. Following SLPI-siRNA transduction, the proliferative capacity of the AsPC-1, BxPC-3 and PANC-1 cells was significantly inhibitions, compared to the blank (PDAC-wild type cells) and negative (non-targeting scrambled siRNA transduced PDAC cells) control ones, respectively (P < 0.05). Moreover, SLPI knockdown significantly increased the apoptosis fractions and reduced the migration and invasion of PDAC cells in vitro (P < 0.05).

CONCLUSIONS

The present study demonstrated that: i) SLPI played an important role in PDAC progression; ii) SLPI might be an important characteristic of malignant PDAC associated with migration and invasion in vitro; and iii) siRNA targeting to SLPI might be a potential therapeutic strategy for the treatment of PCC.

Lard-based high-fat diet increases secretory leukocyte protease inhibitor expression and attenuates the inflammatory response of acute lung injury in endotoxemic rats

BACKGROUND & AIMS

Acute lung injury (ALI) is less severe in obese than in nonobese patients, but the mechanism is unclear. Secretory leukocyte protease inhibitor (SLPI) is the key anti-inflammatory protein in various lung diseases. We have previously reported changes of the surgical stress in obese rats using lard-based high-fat diet (HFD). The purpose of this study was to elucidate the effect of lard-based HFD on the pathophysiology of lipopolysaccharide (LPS)-induced ALI, and the role of SLPI expression.

METHODS

Male Wistar rats were fed lard-based HFD (60 kcal% fat) or control diet (CD) for either 4 or 12 weeks and were killed after intraperitoneal LPS injection. Analyses included messenger RNA expression of TNF-α, macrophage inflammatory protein (MIP)-2, inducible nitric oxide synthase (iNOS), IL-10 and SLPI in the lung tissue and bronchoalveolar lavage fluid, and histology of the lungs.

RESULTS

Rats fed HFD for 12 weeks showed suppression of the lung injury and oxidative stress after LPS injection, as indicated by reduction of pulmonary TNF-α, MIP-2 and iNOS mRNA expression and 8-hydroxy-2'-deoxyguanosine immunostaining. The increased pulmonary SLPI caused by lard was associated with decreased pro-inflammatory cytokines and oxidative stress, which eventually resulted in the prevention of ALI. Those effects of lard on LPS-induced ALI were greater after 12 weeks than after 4 weeks feeding, as indicated by the reduction of TNF-α, MIP-2 and iNOS levels.

CONCLUSIONS

Feeding lard-based HFD for 12 weeks attenuated LPS-induced ALI with increased pulmonary SLPI expression in rats.

Role of GM-CSF in the inflammatory cytokine network that regulates neutrophil influx into the colonic mucosa during Clostridium difficile infection in mice

Clostridium difficile infection in antibiotic-treated mice results in acute colitis characterized by severe intestinal histopathology, robust neutrophil influx, and increased expression of numerous inflammatory cytokines, including GM-CSF. We utilized a neutralizing monoclonal antibody (mAb) against GM-CSF in a murine model to study the role of GM-CSF during acute C. difficile colitis. Cefoperazone-treated mice were challenged with C. difficile (strain 630) spores. Expression of GM-CSF was significantly increased in animals challenged with C. difficile. Treatment with an anti-GM-CSF mAb did not alter C. difficile colonization levels, weight loss, or expression of IL-22 and RegIIIγ. However, expression of the inflammatory cytokines TNFα and IL-1β, as well as iNOS, was significantly reduced following anti-GM-CSF treatment. Expression of the neutrophil chemokines CXCL1 and CXCL2, but not the chemokines CCL2, CCL4, CXCL9, and CXCL10, was significantly reduced by anti-GM-CSF treatment. Consistent with a decrease in neutrophil-attractant chemokine expression, there were fewer neutrophils in histology sections and a reduction in the expression of secretory leukocyte protease inhibitor (SLPI), a tissue anti-protease that protects against damage by secreted neutrophil elastase. These data indicate that GM-CSF plays a role in the inflammatory signaling network that drives neutrophil recruitment in response to C. difficile infection but does not appear to play a role in clearance of the infection.

Secretory leukocyte protease inhibitor modulates urethane-induced lung carcinogenesis

Secretory leukocyte protease inhibitor (SLPI), 11.7 kDa serine protease inhibitor, is produced primarily in the respiratory tract, but it is often elevated in lung, head/neck and ovarian cancers. SLPI expression in relation to cancer progression, metastasis and invasion has been studied extensively in non-small cell lung cancer. However, the role of SLPI during the early stages of carcinogenesis remains unknown. We hypothesized that SLPI is required from the initiation and promotion to the progression of lung carcinogenesis. A skin allograft model using SLPI-knockout (SLPI-KO) mice and short hairpin RNA-treated cells was used to demonstrate that SLPI expression in tumor cells is crucial for tumor formation. Moreover, lung tumorigenesis induced by urethane, a chemical lung carcinogen, was significantly suppressed in SLPI-KO mice in association with decreased nuclear factor-kappaB (NF-κB) activity. SLPI deficiency also resulted in decreased cell numbers and decreased production of inflammatory cytokines in bronchoalveolar lavage fluids. The suppression of NF-κB activation in SLPI-KO mice was associated with lower expression of NF-κB-related survival genes and DNA repair genes. Our findings demonstrate that SLPI plays an important role from the initial stages of lung carcinogenesis to the progression of lung cancer in an NF-κB-dependent manner.

Mechanisms of granulin deficiency: lessons from cellular and animal models

The identification of causative mutations in the (pro)granulin gene (GRN) has been a major breakthrough in the research on frontotemporal dementia (FTD). So far, all FTD-associated GRN mutations are leading to neurodegeneration through a “loss-of-function” mechanism, encouraging researchers to develop a growing number of cellular and animal models for GRN deficiency. GRN is a multifunctional secreted growth factor, and loss of its function can affect different cellular processes. Besides loss-of-function (i.e., mostly premature termination codons) mutations, which cause GRN haploinsufficiency through reduction of GRN expression, FTD-associated GRN missense mutations have also been identified. Several of these missense mutations are predicted to increase the risk of developing neurodegenerative diseases through altering various key biological properties of GRN-like protein secretion, proteolytic processing, and neurite outgrowth. With the use of cellular and animal models for GRN deficiency, the portfolio of GRN functions has recently been extended to include functions in important biological processes like energy and protein homeostasis, inflammation as well as neuronal survival, neurite outgrowth, and branching. Furthermore, GRN-deficient animal models have been established and they are believed to be promising disease models as they show accelerated aging and recapitulate at least some neuropathological features of FTD. In this review, we summarize the current knowledge on the molecular mechanisms leading to GRN deficiency and the lessons we learned from the established cellular and animal models. Furthermore, we discuss how these insights might help in developing therapeutic strategies for GRN-associated FTD.

Integrated analysis of multiple gene expression profiling datasets revealed novel gene signatures and molecular markers in nasopharyngeal carcinoma

PURPOSE

To identify the novel gene signatures and molecular markers of nasopharyngeal carcinoma (NPC) by integrated bioinformatics analysis of multiple gene expression profiling datasets.

EXPERIMENTAL DESIGN

Seven published gene expression profiling studies and one of our unpublished works were reanalyzed to identify the common significantly dysregulated (CSD) genes in NPC. Overrepresentation analysis of cytogenetic bands, Gene Ontology (GO) categories, pathways were used to explore CSD genes functionally associated with carcinogenesis. The protein expressions of selected CSD genes were examined by immunohistochemistry on tissue microarrays, and the correlations of their expressions with clinical outcomes were evaluated.

RESULTS

Using the criteria (genes reported deregulated in more than one study), a total of 962 genes were identified as the CSD genes in NPC. Four upregulated (BUB1B, CCND2, CENPF, and MAD2L1) and two downregulated (LTF and SLPI) genes were markedly reported in six studies. The enrichments of chromosome aberrations were 2q23, 2q31, 7p15, 12q15, 12q22, 18q11, and 18q12 in upregulated genes and 14q32 and 16q13 in downregulated genes. The activated GO categories and pathways related to proliferation, adhesion, invasion, and downregulated immune response had been functionally associated with NPC. SLPI significantly downregulated in nasopharyngeal adenocarcinoma. Furthermore, the high expression of BUB1B or CENPF was associated with poor overall survival of patients.

CONCLUSION

It was first clearly identified the dysregulated expression of BUB1B and SLPI in NPC tissues.

IMPACT

Further studies of the CSD genes as gene signatures and molecular markers of NPC might improve the understanding of the disease and identify new therapeutic targets.

Serine leucocyte proteinase inhibitor-treated monocyte inhibits human CD4(+) lymphocyte proliferation

Serine leucocyte proteinase inhibitor (SLPI) is the main serine proteinase inhibitor produced by epithelial cells and has been shown to be a pleiotropic molecule with anti-inflammatory and microbicidal activities. However, the role of SLPI on the adaptive immune response is not well established. Therefore, we evaluated the effect of SLPI on lymphocyte proliferation and cytokine production. Human peripheral blood mononuclear cells (PBMC) were treated with mitogens plus SLPI and proliferation was assessed by [(3) H]thymidine uptake. The SLPI decreased the lymphocyte proliferation induced by interleukin-2 (IL-2) or OKT3 monoclonal antibodies in a dose-dependent manner. Inhibition was not observed when depleting monocytes from the PBMC and it was restored by adding monocytes and SLPI. SLPI-treated monocyte slightly decreased MHC II and increased CD18 expression, and secreted greater amounts of IL-4, IL-6 and IL-10 in the cell culture supernatants. SLPI-treated monocyte culture supernatant inhibited the CD4(+) lymphocyte proliferation but did not affect the proliferation of CD8(+) cells. Moreover, IL-2 increased T-bet expression and the presence of SLPI significantly decreased it. Finally, SLPI-treated monocyte culture supernatant dramatically decreased interferon-γ but increased IL-4, IL-6 and IL-10 in the presence of IL-2-treated T cells. Our results demonstrate that SLPI target monocytes, which in turn inhibit CD4 lymphocyte proliferation and T helper type 1 cytokine secretion. Overall, these results suggest that SLPI is an alarm protein that modulates not only the innate immune response but also the adaptive immune response.

PM 2.5 collected in a residential area induced Th1-type inflammatory responses with oxidative stress in mice

Epidemiologists have tried to establish an association between human health and exposure to particulate matter (PM). In addition, many researchers have investigated the adverse effects of PM as a trigger of cardiovascular and pulmonary diseases. It is known that a number of environmental contaminants are attached to PM and the toxicity of PM may depend on the sources. We investigated the effects of PM collected in a residential area of Seoul on the immunotoxic responses including cytokine production in BAL fluid and in blood after a single intratracheal instillation in mice with the characterization of physico-chemical properties of PM 2.5 samples. As results, pro-inflammatory cytokines (IL-1, TNF-α, and IL-6), Th0-type cytokine (IL-2), and Th1-type cytokines (IL-12 and IFN-γ) were increased by a dose-dependent manner. Cell infiltration in the alveolar area and phagocytosis by macrophage was observed until day 28 after instillation. The expressions of oxidative stress-related genes (HSP 1a, HSP 8, and SOD) and tissue damage-related genes (MMP-15, -19, and Slpi) were time-dependently increased. PM 2.5 also induced an increase of T cell distribution in lymphocyte and decreased the CD4+/CD8+ ratio. Based on the results, we suggest that PM 2.5 collected in a residential area of Seoul may induce Th1 type-inflammatory responses with oxidative stress and trigger adverse effects in human health.

Paracrine factors of multipotent stromal cells ameliorate lung injury in an elastase-induced emphysema model

Multipotent stromal cells (MSCs) ameliorate several types of lung injury. The differentiation of MSCs into specific cells at the injury site has been considered as the important process in the MSC effect. However, although MSCs reduce destruction in an elastase-induced lung emphysema model, MSC differentiation is relatively rare, suggesting that MSC differentiation into specific cells does not adequately explain the recuperation observed. Humoral factors secreted by MSCs may also play an important role in ameliorating emphysema. To confirm this hypothesis, emphysema was induced in the lungs of C57BL/6 mice by intratracheal elastase injection 14 days before intratracheal MSC or phosphate-buffered saline (PBS) administration. Thereafter, lungs were collected at several time points and evaluated. Our results showed that MSCs reduced the destruction in elastase-induced emphysema. Furthermore, double immunofluorescence staining revealed infrequent MSC engraftment and differentiation into epithelial cells. Real-time PCR showed increased levels of hepatocyte growth factor (HGF) and epidermal growth factor (EGF). Real-time PCR and western blotting showed enhanced production of secretory leukocyte protease inhibitor (SLPI) in the lung. In-vitro coculture studies confirmed the in vivo observations. Our findings suggest that paracrine factors derived from MSCs is the main mechanism for the protection of lung tissues from elastase injury.

Oral benzo[a]pyrene-induced cancer: two distinct types in different target organs depend on the mouse Cyp1 genotype

Benzo[a]pyrene (BaP) is a prototypical polycyclic aromatic hydrocarbon (PAH) found in combustion processes. Cytochrome P450 1A1 and 1B1 enzymes (CYP1A1 and CYP1B1) can both detoxify PAHs and activate them to cancer-causing reactive intermediates. Following high dosage of oral BaP (125 mg/kg/day), ablation of the mouse Cyp1a1 gene causes immunosuppression and death within ∼28 days, whereas Cyp1(+/+) wild-type mice remain healthy for >12 months on this regimen. In this study, male Cyp1(+/+) wild-type, Cyp1a1(-/-) and Cyp1b1(-/-) single-knockout and Cyp1a1/1b1(-/-) double-knockout mice received a lower dose (12.5 mg/kg/day) of oral BaP. Tissues from 16 different organs-including proximal small intestine (PSI), liver and preputial gland duct (PGD)-were evaluated; microarray cDNA expression and >30 mRNA levels were measured. Cyp1a1(-/-) mice revealed markedly increased CYP1B1 mRNA levels in the PSI, and between 8 and 12 weeks developed unique PSI adenomas and adenocarcinomas. Cyp1a1/1b1(-/-) mice showed no PSI tumors but instead developed squamous cell carcinoma of the PGD. Cyp1(+/+) and Cyp1b1(-/-) mice remained healthy with no remarkable abnormalities in any tissue examined. PSI adenocarcinomas exhibited striking upregulation of the Xist gene, suggesting epigenetic silencing of specific genes on the Y-chromosome; the Rab30 oncogene was upregulated; the Nr0b2 tumor suppressor gene was downregulated; paradoxical overexpression of numerous immunoglobulin kappa- and heavy-chain variable genes was found-although the adenocarcinoma showed no immunohistochemical evidence of being lymphatic in origin. This oral BaP mouse paradigm represents an example of "gene-environment interactions" in which the same exposure of carcinogen results in altered target organ and tumor type, as a function of just 1 or 2 globally absent genes.

Signaling from the secretory granule to the nucleus: Uhmk1 and PAM

Neurons and endocrine cells package peptides in secretory granules (large dense-core vesicles) for storage and stimulated release. Studies of peptidylglycine alpha-amidating monooxygenase (PAM), an essential secretory granule membrane enzyme, revealed a pathway that can relay information from secretory granules to the nucleus, resulting in alterations in gene expression. The cytosolic domain (CD) of PAM, a type 1 membrane enzyme essential for the production of amidated peptides, is basally phosphorylated by U2AF homology motif kinase 1 (Uhmk1) and other Ser/Thr kinases. Proopiomelanocortin processing in AtT-20 corticotrope tumor cells was increased when Uhmk1 expression was reduced. Uhmk1 was concentrated in the nucleus, but cycled rapidly between nucleus and cytosol. Endoproteolytic cleavage of PAM releases a soluble CD fragment that localizes to the nucleus. Localization of PAM-CD to the nucleus was decreased when PAM-CD with phosphomimetic mutations was examined and when active Uhmk1 was simultaneously overexpressed. Membrane-tethering Uhmk1 did not eliminate its ability to exclude PAM-CD from the nucleus, suggesting that cytosolic Uhmk1 could cause this response. Microarray analysis demonstrated the ability of PAM to increase expression of a small subset of genes, including aquaporin 1 (Aqp1) in AtT-20 cells. Aqp1 mRNA levels were higher in wild-type mice than in mice heterozygous for PAM, indicating that a similar relationship occurs in vivo. Expression of PAM-CD also increased Aqp1 levels whereas expression of Uhmk1 diminished Aqp1 expression. The outlines of a pathway that ties secretory granule metabolism to the transcriptome are thus apparent.

Secretory leukocyte protease inhibitor antagonizes paclitaxel in ovarian cancer cells

PURPOSE

Ovarian cancer recurrence with the development of paclitaxel resistance is an obstacle to long-term survival. We showed that secretory leukocyte protease inhibitor (SLPI) is a survival factor for ovarian cancer. We hypothesize that SLPI may antagonize paclitaxel injury.

EXPERIMENTAL DESIGN

Differential SLPI induction in response to paclitaxel and in response to stable forced expression of SLPI was shown in A2780-1A9 cells and their paclitaxel-resistant sublines, PTX10 and PTX22, and confirmed with HEY-A8 cells. SLPI-mediated survival was reduced by the MAP/extracellular signal-regulated kinase (ERK) kinase inhibitor, U0126, and a humanized neutralizing monoclonal anti-SLPI antibody, CR012. OVCAR3 xenographs tested the role of CR012 in vivo.

RESULTS

SLPI expression was lower in A2780-1A9 ovarian cancer cells than in PTX10 and PTX22, and SLPI was induced by paclitaxel exposure. Stable SLPI expression yielded a proliferation advantage (P = 0.01); expression of and response to SLPI in OVCAR3 cells were abrogated by exposure to CR012. SLPI reduced the paclitaxel susceptibility of 1A9 and HEY-A8 cells (P <or= 0.05), and SLPI expression did not increase the resistance of PTX10 and PTX22 cells. Both paclitaxel and SLPI overexpression induced ERK activation. Inhibition of MAP/ERK kinase with U0126 increased paclitaxel injury and overcame SLPI-mediated cell protection. It did not reinstate PTX10 sensitivity to paclitaxel, which was associated with AKT activation. Significant inhibition of OVCAR3 xenograft growth was observed with CR012 and paclitaxel, over single agents (P <or= 0.001).

CONCLUSIONS

A two-pronged approach confirmed that SLPI overcomes paclitaxel in part through activation of ERK1/2. These results credential SLPI as a molecular target for ovarian cancer and suggest CR012 as a tool for proof of concept.

Induction of chronic inflammation in mice treated with titanium dioxide nanoparticles by intratracheal instillation

Titanium dioxide nanoparticles (TNP) are nanomaterials which have various applications including photocatalysts, cosmetics, and pharmaceuticals because of their high stability, anticorrosiveness, and photocatalytic properties. Induction of cytokines and potential chronic inflammation were investigated in mice treated with TNP (5 mg/kg, 20 mg/kg, and 50 mg/kg) by a single intratracheal instillation. Pro-inflammatory cytokines such as IL-1, TNF-a, and IL-6 were significantly induced in a dose-dependent manner at day 1 after instillation. The levels of Th1-type cytokines (IL-12 and IFN-gamma) and Th2-type cytokines (IL4, IL-5 and IL-10) were also elevated dose-dependently at day 1 and the inflammatory responses were sustained until the remainder of experimental period for 14 days. By the induction of Th2-type cytokines, the increased B cell distributions both in spleen and in blood, and increased IgE production in BAL fluid and serum were observed. In lung tissue, increase of inflammatory proteins (MIP and MCP) and granuloma formation were observed. Furthermore, the expressions of genes related with antigen presentation (H2-T23, H2-T17, H2-K1, and H2-Eb1) and genes related with the induction of chemotaxis of immune cells (Ccl7, Ccl3, Cxcl1, Ccl4, Ccl2) were markedly increased using microarray analysis. From these data, it could be suggested that TNP possibly cause chronic inflammatory diseases through Th2-mediated pathway in mice.