Tumor neutrophil elastase is closely associated with the direct extension of non-small cell lung cancer into the aorta

Targeting neutrophil elastase is a promising direction for future cancer treatment

Neutrophil elastase (NE) is a proteolytic enzyme released extracellular during the formation of neutrophil extracellular traps (NETs) through degranulation. In addition to participating in the body's inflammatory response, NE also plays an important role in cancer. It can promote tumor proliferation, migration, and invasion, induce epithelial-mesenchymal transition (EMT), and change the tumor microenvironment (TME) to promote tumor progression. Concurrently, NE promotes systemic treatment resistance by inducing EMT. However, it can also selectively kill cancer cells and attenuate tumor development. Sivelestat is a specific NE inhibitor that can be used in the perioperative period of esophageal cancer patients to reduce the incidence of postoperative complications after esophagectomy. In addition, the combination of sivelestat and trastuzumab can enhance the efficacy of human epidermal growth factor receptor 2(HER 2) positive breast cancer patients. Meanwhile, targeting the human antibody domains and fragments of NE is also a new way to treat cancer and inflammation-related diseases. This review provides valuable insights into the role of NE in cancer treatment. Additionally, we discuss the challenges associated with the clinical application of sivelestat. By shedding light on the promising potential of NE, this review contributes to the advancement of cancer treatment strategies.

Identification and characterization of aptameric inhibitors of human neutrophil elastase

Human neutrophil elastase (HNE) plays a pivotal role in innate immunity, inflammation, and tissue remodeling. Aberrant proteolytic activity of HNE contributes to organ destruction in various chronic inflammatory diseases including emphysema, asthma, and cystic fibrosis. Therefore, elastase inhibitors could alleviate the progression of these disorders. Here, we used the systematic evolution of ligands by exponential enrichment to develop ssDNA aptamers that specifically target HNE. We determined the specificity of the designed inhibitors and their inhibitory efficacy against HNE using biochemical and in vitro methods, including an assay of neutrophil activity. Our aptamers inhibit the elastinolytic activity of HNE with nanomolar potency and are highly specific for HNE and do not target other tested human proteases. As such, this study provides lead compounds suitable for the evaluation of their tissue-protective potential in animal models.

Neutrophils in Cancer and Potential Therapeutic Strategies Using Neutrophil-Derived Exosomes

Neutrophils are the most abundant immune cells and make up about 70% of white blood cells in human blood and play a critical role as the first line of defense in the innate immune response. They also help regulate the inflammatory environment to promote tissue repair. However, in cancer, neutrophils can be manipulated by tumors to either promote or hinder tumor growth depending on the cytokine pool. Studies have shown that tumor-bearing mice have increased levels of neutrophils in peripheral circulation and that neutrophil-derived exosomes can deliver various cargos, including lncRNA and miRNA, which contribute to tumor growth and degradation of extracellular matrix. Exosomes derived from immune cells generally possess anti-tumor activities and induce tumor-cell apoptosis by delivering cytotoxic proteins, ROS generation, H2O2 or activation of Fas-mediated apoptosis in target cells. Engineered exosome-like nanovesicles have been developed to deliver chemotherapeutic drugs precisely to tumor cells. However, tumor-derived exosomes can aggravate cancer-associated thrombosis through the formation of neutrophil extracellular traps. Despite the advancements in neutrophil-related research, a detailed understanding of tumor-neutrophil crosstalk is still lacking and remains a major barrier in developing neutrophil-based or targeted therapy. This review will focus on the communication pathways between tumors and neutrophils, and the role of neutrophil-derived exosomes (NDEs) in tumor growth. Additionally, potential strategies to manipulate NDEs for therapeutic purposes will be discussed.

Sequence Preference and Scaffolding Requirement for the Inhibition of Human Neutrophil Elastase by Ecotin Peptide

Human neutrophil elastase (hNE) is an abundant serine protease that is a major constituent of lung elastolytic activity. However, when secreted in excess, if not properly attenuated by selective inhibitor proteins, it can have detrimental effects on host tissues, leading to chronic lung inflammation and non-small cell lung cancer. To improve upon the design of inhibitors against hNE for therapeutic applications, here, we report the crystal structure of hNE in complex with an ecotin-derived peptide inhibitor. We show that the peptide binds in the non-prime substrate binding site. Unexpectedly, compared with full-length ecotin, we find that our short linear peptides and circular amide-backbone-linked peptides of ecotin are incapable of efficient hNE inhibition. Our structural insights point to a preferred amino acid sequence and the potential benefit of a scaffold for optimal binding and function of the peptide inhibitor, both of which are retained in the full-length ecotin protein. These findings will aid in the development of effective peptide-based inhibitors against hNE for targeted therapy. This article is protected by copyright. All rights reserved.

AXL cooperates with EGFR to mediate neutrophil elastase-induced migration of prostate cancer cells

Neutrophil elastase (NE) promotes multiple stages of tumorigenesis. However, little is known regarding the molecular mechanisms underlying its stimulatory role. This study shows that NE triggers dose-dependent ERK signaling and cell migration in a panel of prostate cell lines representing the spectrum of prostate cell malignancy. All cell lines tested internalize NE; however, NE endocytosis is not required for ERK activation. Instead, NE acts extracellularly by stimulating the release of amphiregulin to initiate EGFR-dependent signaling. Inhibiting amphiregulin's biological activity with neutralizing antibodies, as well as gene silencing of amphiregulin or EGFR, attenuates NE-induced migration in normal and benign prostatic cells. Alternatively, in prostate cancer cells, knockdown of receptor tyrosine kinase AXL, but not EGFR, impairs both basal and NE-stimulated migration. When prostate cells progress to malignancy, the switch from EGFR-to AXL-dependence in NE-mediated migration implies the potential combined application of EGFR and AXL targeted therapy in prostate cancer treatment.

Human Antibody Domains and Fragments Targeting Neutrophil Elastase as Candidate Therapeutics for Cancer and Inflammation-Related Diseases

Neutrophil elastase (NE) is a serine protease released during neutrophil maturation. High levels of NE are related to lung tissue damage and poor prognosis in cancer; thus, NE is a potential target for therapeutic immunotherapy for multiple lung diseases and cancers. Here, we isolate and characterize two high-affinity, specific, and noncompetitive anti-NE antibodies Fab 1C10 and V_H 1D1.43 from two large phage-displayed human Fab and V_H libraries. After fusion with human IgG1 Fc, both of them (V_H-Fc 1D1.43 and IgG1 1C10) inhibit NE enzymatic activity with V_H-Fc 1D1.43 showing comparable inhibitory effects to that of the small molecule NE inhibitor SPCK and IgG1 1C10 exhibiting even higher (2.6-fold) activity than SPCK. Their epitopes, as mapped by peptide arrays combined with structural modeling, indicate different mechanisms for blocking NE activity. Both V_H-Fc and IgG1 antibodies block NE uptake by cancer cells and fibroblast differentiation. V_H-Fc 1D1.43 and IgG1 1C10 are promising for the antibody-based immunotherapy of cancer and inflammatory diseases.

The Prognostic Value of Inflammation Factors in Hepatocellular Carcinoma Patients with Hepatic Artery Interventional Treatments: A Retrospective Study

Background

Hepatic artery interventional therapy has been recognized as the first choice for advanced liver cancer. However, reliable prognostic markers are still lacking. In the present study, we aimed to evaluate the prognostic value of inflammation factors including neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) and monocyte to lymphocyte ratio (MLR) in hepatocellular carcinoma (HCC) patients with hepatic artery interventional treatments.

Methods

Patients undergoing hepatic artery interventional therapy after being diagnosed with HCC between 2007 and 2014 were enrolled. Pre-treatment NLR, PLR and MLR were calculated, and all factors including gender, age, TNM stage, BCLC staging, inflammation factors, LDH, ALP, CEA, AFP, hepatitis, liver cirrhosis, portal vein involvement, surgical history and hepatic artery interventional treatment on overall survival (OS) were evaluated by the univariate and multivariate Cox proportional hazards analyses.

Results

Overall, 407 patients were included. The optimal cutoff values determined by receiver operating characteristic (ROC) curve analyses for NLR, PLR and MLR were 3.82, 140.00 and 0.27, respectively. High NLR was associated with worse OS (median survival time: high NLR group 9 vs low NLR group 19 months, HR 1.842, 95% CI: 1.457–2.329, P<0.001). Elevated PLR was negatively correlated with OS (8 vs 18 months, HR 1.677, 95% CI: 1.302–2.161, P<0.001). Patients in high MLR group had a worse OS (10 vs 21 months, HR 1.626, 95% CI: 1.291–2.048, P<0.001). In multivariate analysis, NLR, LDH, ALP and portal vein involvement were independent prognostic factors for OS of HCC patients after hepatic artery interventional therapy. In addition, for patients in BCLC stage A and B, higher NLR, PLR and MLR were all significantly negatively correlated to median survival time (NLR: 17 vs 26 months, HR: 1.739 (95% CI: 1.279–2.365), P<0.001; PLR: 18 vs 26 months, HR: 1.681 (95% CI: 1.245–2.271), P=0.001; MLR: 20 vs 26 months, HR: 1.589 (95% CI: 1.185–2.129), P=0.002).

Conclusion

Elevated pre-treatment NLR, PLR and MLR were associated with worse survival time in HCC patients after hepatic artery interventional therapy. Among them, NLR was an independent prognostic factor for OS.

Neutrophils: Accomplices in metastasis

Metastasis is a critical cause of treatment failure and death in patients with advanced malignancies. Tumor cells can leave the primary site and enter the bloodstream; these circulating tumor cells then colonize target organs by overcoming blood shear stress, evading immune surveillance, and silencing the offensive capabilities of immune cells, eventually forming metastatic foci. From leaving the primary focus to the completion of distant metastasis, malignant tumor cells are supported and/or antagonized by certain immune cells. In particular, it has been found that myeloid granulocytes play an important role in this process. This review therefore aims to comprehensively describe the significance of neutrophils in solid tumor metastasis in terms of their supporting role in initiating the invasion and migration of tumor cells and assisting the colonization of circulating tumor cells in distant target organs, with the hope of providing insight into and ideas for anti-tumor metastasis treatment of tumor patients.

Neutrophil elastase from myeloid cells promotes TSC2-null tumor growth

Chronic inflammation promotes progression of many cancers, with circulating myeloid-derived suppressor cell (MDSC) levels correlating with poor prognosis. Here we examine effects of MDSCs on lymphangioleiomyomatosis (LAM), a rare disease occurring almost exclusively in women whereby estrogen-sensitive metastatic TSC2-null tumors grow throughout the lungs, markedly reducing pulmonary function. The LAM cell origin remains unknown; however, previous work demonstrated that Tsc2 inactivation in the mouse uterus induced estrogen-dependent myometrial tumors with nearly all features of LAM. Half of these animals developed metastatic myometrial tumors in the lungs, suggesting that LAM cells might originate from the myometrium, possibly explaining its overwhelming female prevalence and estrogen-sensitivity. Here we report that MDSC levels, and in particular granulocytic myeloid cell levels, are elevated in the periphery and in tumors of uterine-specific Tsc2-null mice. Importantly, MDSC depletion or inhibition of their recruitment impairs myometrial tumor growth. RNA and protein analysis of Tsc2-null myometrial tumors and xenografts demonstrate high expression and activity of the serine protease neutrophil elastase (NE), with selective qPCR studies indicating a stromal origin of the NE. Notably, treatment with sivelestat, a known NE inhibitor already approved for human use in some countries, reduces tumor growth similar to MDSC depletion. Furthermore, NE promotes Tsc2-null tumor cell growth, migration, and invasion in vitro. Finally, NE-expressing myeloid cells are present throughout the lungs of LAM patients but not controls. These data suggest that NE derived from granulocytic myeloid cells might directly promote LAM tumor cell progression and could be a novel therapeutic target for LAM.

Neutrophil Elastase and Neutrophil Extracellular Traps in the Tumor Microenvironment

Tumor-associated neutrophils (TANs) play a major role during cancer development and progression in the tumor microenvironment. Neutrophil elastase (NE) is a serine protease normally expressed in neutrophil primary granules. Formation of neutrophil extracellular traps (NETs), a mechanism used by neutrophils, has been traditionally associated with the capture and killing of bacteria. However, there are recent discoveries suggesting that NE secretion and NETs formation are also involved in the tumor microenvironment. Here, we focus on how NE and NETs play a key regulatory function in the tumor microenvironment, such as tumor proliferation, distant metastasis, tumor-associated thrombosis, and antitumor activity. Additionally, the potential use of NETs, NE, or associated molecules as potential disease activity biomarkers or therapeutic targets will be introduced.

Neutrophil Extracellular Traps Drive Mitochondrial Homeostasis in Tumors to Augment Growth

Neutrophil infiltration and neutrophil extracellular traps (NET) in solid cancers are associated with poorer prognosis, but the mechanisms are incompletely understood. We hypothesized that NETs enhance mitochondrial function in tumor cells, providing extra energy for accelerated growth. Metastatic colorectal cancer tissue showed increased intratumoral NETs and supranormal preoperative serum MPO-DNA, a NET marker. Higher MPO-DNA correlated with shorter survival. In mice, subcutaneous tumor implants and hepatic metastases grew slowly in PAD4-KO mice, genetically incapable of NETosis. In parallel experiments, human cancer cell lines grew slower in nu/nu mice treated with DNAse, which disassembles NETs. PAD4-KO tumors manifested decreased proliferation, increased apoptosis, and increased evidence of oxidative stress. PAD4-KO tumors had decreased mitochondrial density, mitochondrial DNA, a lesser degree of ATP production, along with significantly decreased mitochondrial biogenesis proteins PGC1α, TFAM, and NRF-1. In vitro, cancer cells treated with NETs upregulated mitochondrial biogenesis-associated genes, increased mitochondrial density, increased ATP production, enhanced the percentage of cancer cells with reduced mitochondrial membrane potential, and increased the oxygen consumption rate. Furthermore, NETs increased cancer cells' expression of fission and fusion-associated proteins, DRP-1 and MFN-2, and mitophagy-linked proteins, PINK1 and Parkin. All of which were decreased in PAD4-KO tumors. Mechanistically, neutrophil elastase released from NETs activated TLR4 on cancer cells, leading to PGC1α upregulation, increased mitochondrial biogenesis, and accelerated growth. Taken together, NETs can directly alter the metabolic programming of cancer cells to increase tumor growth. NETs represent a promising therapeutic target to halt cancer progression. SIGNIFICANCE: Neutrophils through the release of NETs facilitate the growth of stressed cancer cells by altering their bioenergetics, the inhibition of which induces cell death.

Neutrophil elastase in the tumor microenvironment

Myeloid cell production within the bone marrow is accelerated in the setting of cancer, and the numbers of circulating and infiltrating neutrophils and granulocytic myeloid derived suppressor cells (MDSCs) correlate with tumor progression and patient survival. Cancer is therefore able to hijack the normally host-protective immune system and use it to further fuel growth and metastasis. Myeloid cells secrete neutrophil elastase and neutrophil extracellular traps (NETs) in response to cues within the tumor microenvironment, thereby leading to enhanced activity in a variety of cancer types. Neutrophil elastase may indeed be a driver of tumorigenesis, since genetic deletion and pharmacological inhibition markedly reduces tumor burden and metastatic potential in numerous preclinical studies. In this review, we examine the current evidence for neutrophil elastase as a stimulatory factor in cancer, focusing on precise mechanisms by which it facilitates primary tumor growth and secondary organ metastasis. We conclude with a brief overview of neutrophil elastase inhibitors and discuss their potential use in cancer therapy.

Preoperative platelet to lymphocyte and neutrophil to lymphocyte ratios are independent prognostic factors for patients undergoing lung cancer radical surgery: A single institutional cohort study

BACKGROUND

The aim of this study was to assess the prognostic value for NSCLC patients who were scheduled to receive lung cancer radical resection.

METHODS

In this cohort study (Dec.2014-Feb.2016), patients with non-small cell lung cancer (NSCLC) who underwent radical lung cancer thoracotomy were enrolled and accessed at postoperative complications, one-year overall survival (OS) and relapse-free survival (RFS). The preoperative PLR and NLR of all patients were calculated based on preoperative complete blood counts. Univariate and multivariate Cox regression analyses were performed to determine the associations of PLR and NLR with OS and RFS.

RESULTS

A total of 174 NSCLC patients were studied. The results indicated that both high PLR (>148.6) and NLR (>2.9) were related to a high rate of postoperative pulmonary complications significantly (49.3%vs.29.1%, P = 0.007; 50.7% vs. 28.6%, P = 0.003). Moreover, NSCLC patients with a high PLR level (> 148.6) was significantly associated with a lower one-year OS (90.3% vs. 77.5%, P = 0.034).

CONCLUSIONS

Preoperative PLR and NLR were good prognostic factors for postoperative pulmonary complications and OS in NSCLC patients undergoing radical lung cancer surgery. Thus, blood PLR and NLR would be helpful as a prognostic tool before radical lung cancer surgery.

Neutrophil elastase as a diagnostic marker and therapeutic target in colorectal cancers

Neutrophil elastase (NE), a serine protease secreted by neutrophils, contributes to the progression of cancers to enhance tumor invasion and metastasis. It has been well reported that the regions surrounding the colorectal cancerous tissues usually are decorated with increased accumulation or aggregation of neutrophils coupled with a higher deposition/expression of NE. Therefore, we hypothesized that an increased expressional level of NE in patients with colorectal cancer (CRC) may represent as one of putative biomarkers for CRC. The aim of this study was to evaluate and assure our hypothesis by measurements of the expressional level of NE in the sera and tissues from CRC patients. Moreover, we also proposed a potential therapeutic strategy by blocking enzymatic activity of NE using sivelestat to inhibit the progression of tumor developments. The infiltrated numbers of neutrophils from specimen tissues of CRC patients, and the secreted forms of NE in the sera were quantitatively measured and compared. To evaluate the serum NE as one of putative biomarkers of CRC patients, the receiver operating characteristic (ROC) curve was made to determine the cut-off value of NE in sera for assurance of CRC diagnosis. To evaluate NE as therapeutic target for CRC, sivelestat, a NE inhibitor, was used and administrated into the CRC xenografts. NE expression level coupled with tumor volume were measured and compared between the control and sivelestat-treated xenografts. We found that more infiltrated neutrophils and an increased NE expression were detected in the cancerous tissues compared to the normal tissues. The serum NE concentration in CRC patients was statistically higher than that in the healthy controls (0.56±0.08 μg/ml vs. 0.22±0.03ug/ml) (p<0.05), indicating that serum NE can potentially be a putative marker of CRC. To characterize the role of NE in tumorigenesis, the NE avtivity was detected in HCT-15-xenografts using in vivo imaging system (IVIS). Compare to normal mice, the amounts of active NE in xenografts are significantly higher than normal control animals. In the therapeutic characterizing studies, we found that sivelestat can inhibit tumor growth in the HCT-15-induced xenografts. This study suggests that NE is not only as a putative diagnostic biomarker of CRC, but also a potential therapeutic target for patients suffered with CRC.

Promotion of lung carcinogenesis by chronic obstructive pulmonary disease-like airway inflammation in a K-ras-induced mouse model

Lung cancer is the leading cause of cancer deaths in the United States. In addition to genetic abnormalities induced by cigarette smoke, several epidemiologic studies have found that smokers with chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lungs, have an increased risk of lung cancer (1.3- to 4.9-fold) compared to smokers without COPD. This suggests a link between chronic airway inflammation and lung carcinogenesis, independent of tobacco smoke exposure. We studied this association by assaying the inflammatory impact of products of nontypeable Haemophilus influenzae, which colonizes the airways of patients with COPD, on lung cancer promotion in mice with an activated K-ras mutation in their airway epithelium. Two new mouse models of lung cancer were generated by crossing mice harboring the LSL-K-ras(G12D) allele with mice containing Cre recombinase inserted into the Clara cell secretory protein (CCSP) locus, with or without the neomycin cassette excised (CCSP(Cre) and CCSP(Cre-Neo), respectively). Lung lesions in CCSP(Cre-Neo)/LSL-K-ras(G12D) and CCSP(Cre)/LSL-K-ras(G12D) mice appeared at 4 and 1 month of age, respectively, and were classified as epithelial hyperplasia of the bronchioles, adenoma, and adenocarcinoma. Weekly exposure of CCSP(Cre)/LSL-K-ras(G12D) mice to aerosolized nontypeable Haemophilus influenzae lysate from age 6-14 weeks resulted in neutrophil/macrophage/CD8 T-cell-associated COPD-like airway inflammation, a 3.2-fold increase in lung surface tumor number (156 +/- 9 versus 45 +/- 7), and an increase in total lung tumor burden. We conclude that COPD-like airway inflammation promotes lung carcinogenesis in a background of a G12D-activated K-ras allele in airway secretory cells.

Prognostic significance of immunoreactive neutrophil elastase in human breast cancer: long-term follow-up results in 313 patients

OBJECTIVE

We have measured the concentration of immunoreactive neutrophil elastase (ir-NE) in the tumor extracts of 313 primary human breast cancers. Sufficient time has elapsed, and we are now ready to analyze its prognostic value in human breast cancer.

METHODS

ir-NE concentration in tumor extracts was determined with an enzyme-linked immunosorbent assay that enables a rapid measurement of both free-form ir-NE and the A1-protease inhibitor-complexed form of ir-NE. We analyzed the prognostic value of this enzyme in human breast cancer in univariate and multivariate analyses.

RESULTS

Patients with breast cancer tissue containing a high concentration of ir-NE had poor survival compared to those with a low concentration of ir-NE at the cutoff point of 9.0 microg/100 mg protein (P = .0012), which had been previously determined in another group of 49 patients. Multivariate stepwise analysis selected lymph node status (P = .0004; relative risk = 1.46) and ir-NE concentration (P = .0013; relative risk = 1.43) as independent prognostic factors for recurrence.

CONCLUSIONS

Tumor ir-NE concentration is an independent prognostic factor in patients with breast cancer who undergo curative surgery. This enzyme may play an active role in tumor progression that leads to metastasis in human breast cancer.

Neutrophil elastase and cancer

This mini-review summarizes our recent experimental and clinical studies on neutrophil elastase (NE) and cancer based on our original view point. Neoplasms metastasize as a result of a complex series of events. This process requires various degradative enzymes including proteases. NE has broad substrate specificity under physiological conditions, and excessive NE results in digestion of not only elastin, but also other extracellular matrix proteins. Several cell lines from human breast cancer and human lung cancer produce immunoreactive NE. The amount of immunoreactive NE in tumor tissue is an independent prognostic indicator of patients with breast cancer and lung cancer. Furthermore, a specific NE inhibitor completely suppressed growth of cancer cells transplanted into severe combined immunodeficiency mice. The use of NE inhibitor would seem to be a promising way to prevent the invasion and metastasis of cancer.

Data Mining for Gene Networks Relevant to Poor Prognosis in Lung Cancer via Backward-Chaining Rule Induction

We use Backward Chaining Rule Induction (BCRI), a novel data mining method for hypothesizing causative mechanisms, to mine lung cancer gene expression array data for mechanisms that could impact survival. Initially, a supervised learning system is used to generate a prediction model in the form of “IF <conditions> THEN <outcome>” style rules. Next, each antecedent (i.e. an IF condition) of a previously discovered rule becomes the outcome class for subsequent application of supervised rule induction. This step is repeated until a termination condition is satisfied. “Chains” of rules are created by working backward from an initial condition (e.g. survival status). Through this iterative process of “backward chaining,” BCRI searches for rules that describe plausible gene interactions for subsequent validation. Thus, BCRI is a semi-supervised approach that constrains the search through the vast space of plausible causal mechanisms by using a top-level outcome to kick-start the process. We demonstrate the general BCRI task sequence, how to implement it, the validation process, and how BCRI-rules discovered from lung cancer microarray data can be combined with prior knowledge to generate hypotheses about functional genomics.

Association of moderate alpha-1 antitrypsin deficiency with lung cancer in the Serbian population

BACKGROUND

Alpha-1 antitrypsin (AAT) is an important serine protease inhibitor in human plasma. Its major physiological role is to inhibit neutrophil elastase (NE) in the lower respiratory tract and protect lung tissue from destruction. Recent studies indicated an etiological role of NE in lung cancer development. The aim of this study was to investigate the association of alpha-1 antitrypsin deficiency (AATD) with lung cancer in patients with four different histological types of cancer: squamous cell carcinoma, adenocarcinomas, large cell carcinoma and small cell carcinoma.

METHODS

Phenotyping was carried out by isoelectric focusing (pH 4.2-4.9). We compared the frequency of AATD phenotypes in 186 lung cancer patients with the value obtained in our previous study in a healthy Serbian population (3.7%) using the Fisher exact test.

RESULTS

Allele frequencies in patients were Pi *M 0.9677, Pi *Z 0.0215, Pi *S 0.0081 and Pi *other rare 0.0027. Eleven of the 186 lung cancer patients (5.9%) were AATD heterozygotes with moderate deficiencies (PiMZ and PiMS). When this value was compared with AATD heterozygote frequency obtained in the healthy individuals (3.7%), the difference was close to the level of significance (p = 0.055). However, individuals with AATD phenotypes had a higher risk of developing squamous cell lung cancer then those with non-deficient AAT variants (OR = 4.51, 95% CI = 1.66-12.29).

CONCLUSIONS

Our findings provide evidence of an association between AAT phenotypes with moderate deficiency and squamous cell lung cancer.

Sivelestat, a specific neutrophil elastase inhibitor, suppresses the growth of gastric carcinoma cells by preventing the release of transforming growth factor-alpha

Neutrophil elastase is a neutral serine proteinase produced by polymorphonuclear leukocytes and monocytes/macrophages, especially under surgical stress. In the present study, we investigated whether NE promotes cell growth by activation of EGFR to elucidate whether surgical stress induces tumor proliferation and progression. Furthermore, we examined the antitumor effect of a specific NE inhibitor, sivelestat. Cell growth assays were carried out in vitro and in vivo using TMK-1 gastric cancer cells. TMK-1 cell growth was stimulated to 118% of that of the control cells after 48 h stimulation with 1 microg/mL NE according to an MTT assay. Sivelestat inhibited cell growth to 23.4 and 58.0% of control values at concentrations of 100 and 1,000 microg/mL, respectively. NE rapidly phosphorylated EGFR in only 5 min and triggered the ERK1/2-mitogenic signaling pathway in TMK-1. It was further demonstrated that NE-induced EGFR phosphorylation was transactivated through TGF-alpha, using ELISA. NE increased the cleavage of TGF-alpha from the cell surface 30-fold compared with the cells without treatment. Interestingly, sivelestat significantly reduced NE-induced EGFR phosphorylation and ERK1/2 activation and completely blocked the release of TGF-alpha from the TMK-1 cell surface. In a xenograft study, the addition of ventrotomy as a surgical stress promoted tumor growth. Sivelestat significantly suppressed the tumor growth induced by surgical stress. These results indicate that sivelestat suppresses the growth of gastric cancer cells by inhibiting the release of TGF-alpha stimulated by NE, which often occurs after surgical stresses.

Role of Proteases in Pancreatic Carcinoma

Proteases play an important role in cancer invasion and metastasis. In this review we specifically discuss the role of these proteases in pancreatic carcinoma. Serine proteases and matrix metalloproteinases are the focus of intense research, as they appear to be related to the process of tumor progression. We discuss the diagnostic and prognostic value of these two groups of proteases. Lastly, we report on the current and recent clinical trials focusing on inhibition of these proteases.

Polymorphisms in the promoter region of neutrophil elastase gene and lung cancer risk

The neutrophil elastase (NE) gene encodes a powerful serine protease that is involved in the process of normal tissue turnover, natural host defense or tissue damage in acute and chronic inflammatory disorders. Furthermore, NE was suggested as one of the determinant factors of individual susceptibility to lung cancer resulting from imbalance between alpha1-antitrypsin (AT) and NE. To determine whether NE plays a role in risk for lung cancer, we screened polymorphisms in the promoter region of the NE gene and assessed the role of the NE polymorphisms in the risk for lung cancer. We confirmed three previously identified polymorphisms which are located at -903, -741, and extra 52 bp STS relative to the transcription initiation site. In addition, two new polymorphisms at -832 (G/T) and -789 (C/T) were identified. Their rare allelic frequencies of new polymorphism are 0.02 and 0.01, respectively, among Caucasians. The prevalence of the NE -903 (T/T) and (T/G) genotypes were 0.88 and 0.12 in controls as compared to 0.96 and 0.04 in lung cancer patients using genomic DNA isolated from 113 Caucasian lung cancer cases and 131 controls. A significant increase in lung cancer risk was observed for expected high NE activity genotypes (OR=3.2, 95% CI=1.02-10.3) as compared to low NE activity genotypes. These results were consistent with previous in vitro functional analysis, which reported an approximately two-fold increase enzyme expression with the -903T/-741G allele as compared to the -903G/-741A variant. These results confirm that the NE promoter region polymorphisms may influence in risk for lung cancer.

alpha1-antitrypsin and its C-terminal fragment attenuate effects of degranulated neutrophil-conditioned medium on lung cancer HCC cells, in vitro

Background

Tumor microenvironment, which is largely affected by inflammatory cells, is a crucial participant in the neoplastic process through promotion of cell proliferation, survival and migration. We measured the effects of polymorphonuclear neutrophil (PMN) conditioned medium alone, and supplemented with serine proteinase inhibitor α-1 antitrypsin (AAT) or its C-terminal fragment (C-36 peptide), on cultured lung cancer cells.

Methods

Lung cancer HCC cells were grown in a regular medium or in a PMN-conditioned medium in the presence or absence of AAT (0.5 mg/ml) or its C-36 peptide (0.06 mg/ml) for 24 h. Cell proliferation, invasiveness and release of IL-8 and VEGF were analyzed by [³H]-thymidine incorporation, Matrigel invasion and ELISA methods, respectively.

Results

Cells exposed to PMN-conditioned medium show decreased proliferation and IL-8 release by 3.9-fold, p < 0.001 and 1.3-fold, p < 0.05, respectively, and increased invasiveness by 2-fold (p < 0.001) compared to non-treated controls. In the presence of AAT, PMN-conditioned medium loses its effects on cell proliferation, invasiveness and IL-8 release, whereas VEGF is up-regulated by 3.7-fold (p < 0.001) compared to controls. Similarly, C-36 peptide abolishes the effects of PMN-conditioned medium on cell invasiveness, but does not alter its effects on cell proliferation, IL-8 and VEGF release. Direct HCC cell exposure to AAT enhances VEGF, but inhibits IL-8 release by 1.7-fold (p < 0.001) and 1.4-fold (p < 0.01) respectively, and reduces proliferation 2.5-fold (p < 0.01). In contrast, C-36 peptide alone did not affect these parameters, but inhibited cell invasiveness by 51.4% (p < 0.001), when compared with non-treated controls.

Conclusions

Our data provide evidence that neutrophil derived factors decrease lung cancer HCC cell proliferation and IL-8 release, but increase cell invasiveness. These effects were found to be modulated by exogenously present serine proteinase inhibitor, AAT, and its C-terminal fragment, which points to a complexity of the relationships between tumor cell biological activities and local microenvironment.

Role of imbalance between neutrophil elastase and alpha 1-antitrypsin in cancer development and progression

Neutrophil elastase and alpha 1-antitrypsin are a pair of protease and protease inhibitor counterparts. The imbalance between the two counterparts is generally thought to cause tissue damage, which could create a favourable tissue environment for carcinogens and tumour progression. Laboratory research and clinical findings have indicated that a deficiency in alpha1-antitrypsin is associated with increased risk of liver cancer, bladder cancer, gall bladder cancer, malignant lymphoma, and lung cancer. Conversely, raised concentrations of neutrophil elastase might promote the development, invasion, and metastasis of many cancers. Several mechanisms of carcinogenesis have been postulated. Excess neutrophil elastase might facilitate cancer development by causing tissue damage and air trapping, which foster longer carcinogen exposure, might promote cancer progression by degrading the intercellular matrix barrier, and might directly lead to cancer development through the tumour-necrosis-factor signalling pathway.

Quantification of elastase-like activity in 13 human cancer cell lines and in an immortalized human epithelial cell line by RP-HPLC

A sensitive and specific RP-HPLC assay was developed to measure the levels of polymorphonuclear elastase (PMN-E) activity in growing cell cultures. By combining a pre-incubation of the cells with a relatively non-toxic, PMN-E-specific inhibitor, MeOSuc-Ala-Ala-Pro-Val-chloromethylketone (MAAPVCK), the p-nitroaniline formed by the hydrolysis of the substrate MeOSuc-Ala-Ala-Pro-Val-p-NA by PMN-E is quantified. Elastase-like activity was measured in 14 human cells lines: 13 cancer cell lines (HL-60, U-937, A-427, LCLC-103H, YAPC, DAN-G, PA-TU-8902, KYSE-70, -510, -520, 5637, SISO and MCF-7) and one immortalized epithelial cell line (hTert-RPE1). Activity was detected in all lines; the lowest was found in hTert-RPE1 cells while the highest was detected in a pancreas adenocarcinoma line (PA-TU-8902). When the results were normalized according to cell volume instead of cell number, the leukemia line HL-60 had the highest activity and PA-TU-8902 ranked second. A 1 h pre-incubation with 9.0 microM of the irreversible PMN-E inhibitor MAAPVCK led to varying degrees of enzyme inhibition depending on the cell line; the strongest inhibition was observed with the PA-TU-8902 pancreatic cancer cell line (90% inhibition) while the weakest was seen with the A-427 lung cancer cell line (52%). These results indicate that PA-TU-8902 is a suitable in vitro model for testing the efficacy of PMN-E-activated prodrugs of antitumor agents.

A pulmonary metastatic model of human non-small cell lung carcinoma cells that produce a neutrophil elastase-like molecule in severe combined immunodeficiency mice

STUDY OBJECTIVES

To establish a clinically relevant animal model of pulmonary metastases of human non-small cell lung carcinoma (NSCLC) cells in severe combined immunodeficiency (SCID) mice, which can be used for repetitive investigations, so as to improve our understanding and management of the cellular and molecular mechanisms of human lung cancer metastases.

METHODS AND RESULTS

SCID mice subcutaneously injected in the flank with 1 x 10(6) EBC-1 cells derived from human lung squamous cell carcinoma were killed weekly for examination until 12 weeks after tumor inoculation. The biological characteristics of implanted tumors and their metastatic foci were investigated by hematoxylin-eosin staining and immunostaining for neutrophil elastase (NE). Three weeks after ectopic implantation, EBC-1 cell lines formed a tumor at the inoculation site and grew steadily to show a plateau at 10 weeks. EBC-1 cells formed multiple metastases in the lung 7 weeks after tumor inoculation; their numbers increased steadily until 12 weeks in all mice. Immunoreactivity for NE was intense in the metastatic tumor cells. Then, to establish the primary tumor amputation/pulmonary metastasis model and to evaluate how primary tumor amputation influences the development of pulmonary metastases at the cellular and molecular level, excision was performed before (3 weeks and 5 weeks after inoculation) and after (7 weeks and 9 weeks after inoculation) formation of lung metastases. When the primary tumor was excised 3 weeks after tumor inoculation, all mice had pulmonary metastasis at 12 weeks after inoculation. Blood samples obtained at 3 weeks after tumor inoculation contained human beta-actin messenger RNA, which represents circulating tumor cells.

CONCLUSION

Our NSCLC EBC-1 pulmonary metastasis model is reliable, technically simple, and predictably results in pulmonary metastasis from early hematogenous spread. This model may be useful for elucidating the mechanism of pulmonary metastasis in human lung cancer, and testing anti-metastatic efficacy of therapeutic agents in vivo.

Role of elastin-matrix interactions in tumor progression

Data from the literature now indicate that cancer cells can specifically interact with the unique extracellular matrix protein, elastin. The interaction is mediated by two elastin-binding proteins (EBP), S-gal/EBP (organized into the elasin receptor/elastonectin complex) and galectin-3, components of two laminin receptors. Studies revealed that the expression of both EBPs is closely associated to the invasive/metastatic potential of various cancer types. This is due to the fact that elastin-ligation of S-gal/EBP induces motogenic, as well as mitogenic signals and releases various elastases from cancer cells and the induction depends on the metastatic potential. Studies also demonstrated that certain cancer cells can synthesize elastin and express lysyl oxydase, providing explanation for frequent appearance of elastic tissue in tumors such as breast or gastric cancers. Clinico-pathological data suggest some correlation with tumor progression of the presence of the elastic tumor stroma. Since elastic tissue may be a significant reservoir of angiostatic molecule(s) this extracellular matrix protein can also have a role in tumor-induced angiogenesis. Soluble elastin as well as elastin peptides are potent inhibitors of the metastatic process in experimental tumor models. On the other hand, elastin peptides can also be used to design targeted therapies exploiting the unique physicochemical nature of this matrix protein. Altogether, these data suggest a significant role for tumor cell-elastin interactions in tumor progression.

Enzyme-activated targeting of liposomes

It has become increasingly evident that tissues utilize specific localization of enzymes to perform certain tasks, often associated with various types of tissue remodeling. The ubiquitous presence of such enzymes, along with their specific localizations, provides an ideal opportunity to elicit specific delivery via an enzyme-triggered mechanism. A survey of some of the recent progress in enzyme-activated targeting of delivery systems, with a focus on a few liposomal systems, is presented.

Are antineutrophil cytoplasmic antibodies pathogenic? Experimental approaches to understand the antineutrophil cytoplasmic antibody phenomenon

Antineutrophil cytoplasmic antibodies (ANCA) directed against the neutrophil enzymes PR3 and MPO are tightly associated with the development of small vessel vasculitis. This article reviews the large body of data derived from in vitro experiments documenting many different proinflammatory effects of these ANCA on neutrophils, monocytes, and endothelial cells. Taken in conjunction with clinical observations and data from animal models, a concept of the pathogenicity of ANCA emerges.

Elastase activity enhances the adhesion of neutrophil and cancer cells to vascular endothelial cells

BACKGROUND

Elastase activity in cancer cells has been reported to promote their metastasis. Hence, we analyzed the influence of elastase activity of cancer cells on their responsive adhesion to vascular endothelial cells.

MATERIALS AND METHODS

Human pancreatic (S2-007, S2-013, S2-020, S2-028) and colonic (COLO205) cancer cell lines were used. S2-007, S2-013, and S2-020 possess high elastase activity, whereas S2-028 and COLO205 have low elastase activity. Adhesive reactions of these cancer cells and neutrophils to TNFalpha-activated HUVEC were analyzed. Bound cells onto HUVEC were counted after incubation for 10 min. The effects of suppression of elastase activity by ZD8321, a potent elastase inhibitor, and supplementation of human neutrophil elastase (NE) on the adhesive reactions were also analyzed. In addition, E-selectin expression on HUVEC and concentrations of soluble E-selectin in the medium were measured.

RESULTS

Adhesion of cells with high intracellular elastase activity to TNFalpha-activated HUVEC was suppressed by ZD8321. On the other hand, adhesion of cells with low elastase activity was enhanced by exogenous NE. Expression of E-selectin, a key molecule in leukocyte-endothelial cell interaction, on HUVEC was increased by NE. Soluble E-selectin concentration in the medium increased after the adhesive reaction between neutrophils and HUVEC. This increase was thought to be due to the shedding of cell surface E-selectin. Such responses were inhibited by ZD8321.

CONCLUSION

Elastase activity has a biological function of stimulating both the E-selectin expression on HUVEC and the resultant adhesive reaction of cancer cells with them. Inhibition of elastase activity is a potent strategy for controlling cancer metastasis.

beta-Lactam derivatives as enzyme inhibitors: 1-peptidyl derivatives of 4-phenylazetidin-2-one as inhibitors of elastase and papain

N-Peptidyl substituted azetidin-2-ones were synthesized and evaluated as inhibitors of the serine protease elastase, and the cysteine protease papain. All compounds were synthesized from 4-phenylazetidin-2-one, either from the racemate or from the pure enantiomers. The (S)-enantiomer was prepared by enantioselective synthesis from (S)-beta-phenyl-beta-alanine, while the (R)-enantiomer was obtained by enzymatic resolution with alpha-chymotrypsin. N-Alkylation with bromoacetates introduced a spacer group which, after hydrolysis to the free acid, was acylated with amino acid esters or di- or tripeptide esters. The enzymatic assays proved some derivatives to be effective inhibitors of PPE and/or papain. N-BOC protected amino acid derivatives without a spacer group inhibited PPE reversibly, while derivatives with spacer group showed either weak or no inhibitory properties. On the other hand, papain was inactivated irreversibly by ethyl (RS)-2-oxo-4-phenylazetidin-1-acetate. The highest inhibitory activity against papain was found for the diastereomers of N-(2-oxo-4-phenylazetidin-1-acetyl)-L-alanyl-L-valine benzyl ester, a compound with a spacer group.

Elastase activated liposomal delivery to nucleated cells

The specific activation of liposomes for delivery has been explored by enzyme mediated cleavage of a peptide substrate covalently conjugated to a fusogenic lipid. We have previously shown an elastase sensitive peptide conjugated to 1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine [corrected] (DOPE) could be activated by enzymatic cleavage, triggering liposome-liposome lipid mixing and fusion with erythrocyte ghosts (Pak et al., Biochim. Biophys. Acta, 1372 (1998) 13-27). Further optimization of this system has been aimed at obtaining substrate cleavage at or below physiological elastase levels and to demonstrate triggered delivery to living cells. Therefore a new peptide-lipid, MeO-suc-AAPV-DOPE (N-methoxy-succinyl-Ala-Ala-Pro-Val-DOPE), has been developed that exhibits greater sensitivity and selectivity for elastase cleavage and subsequent conversion to DOPE. This peptide-lipid was used with DODAP (dioleoyl dimethylammonium propane, a pH dependent cationic lipid) in a 1:1 mol ratio with the expectation that endocytosis would lead to a liposome with an overall positive charge if enzymatic cleavage had occurred. Elastase treated liposomes displayed pH dependent enhancement of binding, lipid mixing, and delivery of 10000 MW dextrans, relative to untreated liposomes, when incubated with HL60 human leukemic cells. Heat denatured elastase did not activate DODAP/MeO-suc-AAPV-DOPE liposomes, indicating enzymatic activity of elastase is necessary. Liposomes bound to ECV304 endothelial cells at physiological pH could be activated by elastase to deliver an encapsulated fluorescent probe, calcein, into the cell cytoplasm. These results suggest enzyme substrate peptides linked to a fusogenic lipid may be used to elicit specific delivery from liposomes to cells.

Platelet-derived endothelial cell growth factor/thymidine phosphorylase concentrations differ in small cell and non-small cell lung cancer

OBJECTIVE

Platelet-derived endothelial cell growth factor (PD-ECGF)/thymidine phosphorylase (TP) has been implicated in cancer angiogenesis, which is critical for tumor growth and metastasis. We investigated the relationship between the tissue concentration of PD-ECGF/TP and the clinicopathologic status in human lung cancer.

METHODS

The concentrations of PD-ECGF/TP in the tumor extracts of 139 primary human lung carcinomas were measured by using a highly specific and sensitive enzyme-linked immunosorbent assay.

RESULTS

PD-ECGF/TP was detected in the extracts from 137 of 139 specimens at concentrations that ranged from 2.0 to 169.5 U/mg protein. PD-ECGF/TP concentrations in patients with adenocarcinoma (n = 73) and squamous cell carcinoma (n = 49) were (mean +/- SD) 30.7+/-22.9 U/mg protein (range, 7.6 to 169.5 U/mg protein) and 32.0+/-19.8 U/mg protein (range, 8.0 to 84.4 U/mg protein), respectively. No significant difference was found in the PD-ECGF/TP concentration between these two types of non-small cell lung cancer (NSCLC). However, a > 8-fold lower mean concentration of PD-ECGF/TP was found in tissue extracts from small cell lung cancer (SCLC) (n = 17; 3.65+/-2.01 U/mg protein, ranging from undetectable to 6.1 U/mg protein) than in those from adenocarcinomas (p = 0.00005) or squamous cell carcinomas (p < 0.00001).

CONCLUSIONS

The striking difference in PD-ECGF/TP concentrations between SCLC and NSCLC suggests that these two types of lung cancer use alternative pathways for angiogenesis. The present study suggests that inhibitors of PD-ECGF/TP, which have been recently developed and are under laboratory investigation to test their effectiveness as treatments for various types of cancer, may not be effective against SCLC.

High levels of hepatocyte growth factor/scatter factor in diffuse-type bronchioloalveolar cell carcinoma

BACKGROUND

Hepatocyte growth factor/scatter factor (HGF/SF) is a potent mitogen for various neoplastic cells, including neoplastic bronchial epithelia.

METHODS

Immunoreactive hepatocyte growth factor/scatter factor (HGF/SF) was measured in extracts prepared from 129 nonsmall cell lung carcinoma (NSCLC) specimens, using an enzyme-linked immunosorbent assay. These specimens represented 5 cases of solitary/localized bronchioloalveolar cell carcinoma (BAC), 4 cases of diffuse/infiltrative BAC, 90 cases of non-BAC adenocarcinoma, 25 cases of squamous cell carcinoma, and 5 cases of large cell carcinoma.

RESULTS

The mean concentration of immunoreactive HGF/SF was more than 19-fold higher in tissue extracts from diffuse-type BAG (265.0 +/- 110.2 ng/100 mg protein) than in those from solitary-type BAC (13.9 +/- 15.9, P < 0.005), non-BAC adenocarcinoma (13.8 +/- 14.9, P < 0.001), squamous cell carcinoma (13.2 +/- 14.4, P < 0.001), or large cell carcinoma (11.2 +/- 6.5, P < 0.005). When immunohistochemical staining for HGF/SF was performed, intense HGF/SF staining was uniformly observed in diffuse-type BAC tumor cells, but not in solitary-type BAC.

CONCLUSIONS

Although BAC is included as a subtype of adenocarcinoma in the World Health Organization classification, diffuse-type BAC should be considered a distinct biologic entity, at least in terms of HGF/SF expression, from solitary-type BAC or non-BAC adenocarcinoma. In addition, the solitary and diffuse forms of BAC are known to be associated with different prognoses; for the latter, the prognosis is much poorer than for the former. The results of this study may at least partly explain this difference in prognosis.