Proteases as prognostic markers in cancer

A novel discriminant score based on tumor-associated trypsin inhibitor for accurate diagnosis of metastasis in patients with breast cancer

Invasion and metastasis of solid tumors require proteolytic enzymes for degradation of the basal membrane and extracellular matrix. Currently, there are no reliable methodologies to predict the risk for metastatic disease. In this context, our aim has been focused on the development of a noninvasive score based on tumor-associated trypsin inhibitor (TATI) for the assessment of metastasis in patients with breast cancer. TATI, trypsin, and soluble epidermal growth factor receptor (sEGFR) were assayed by enzyme-linked immunosorbent assay. CA 15.3 serum level was assayed by microparticle enzyme immunoassay in 265 patients with breast cancer. Statistical analyses were performed by logistic regression and receiver operating characteristic analysis curves. Using multivariate discriminant analysis, a score is selected based on absolute values of the four biochemical markers: TATI-metastatic breast cancer score (TATI-MBCS) = [0.03 × CA 15.3 (U/L) + 0.039 × TATI (ng/ml) + 0.04 × trypsin (ng/ml) + 0.023 × sEGFR (ng/ml) - 6.49 (numerical constant)]. This function correctly classified 84% of metastatic breast cancer at cutoff value = 0.62 (i.e., greater than 0.62 indicates patients with metastatic breast cancer and less than 0.62 indicates patients with nonmetastatic breast cancer). In conclusion, TATI-MBCS is a novel, noninvasive, and simple score which can be applied to discriminate patients with metastatic breast cancer.

Quantitative Measurement of Protease-Activity with Correction of Probe Delivery and Tissue Absorption Effects

Proteases play important roles in a variety of pathologies from heart disease to cancer. Quantitative measurement of protease activity is possible using a novel spectrally matched dual fluorophore probe and a small animal lifetime imager. The recorded fluorescence from an activatable fluorophore, one that changes its fluorescent amplitude after biological target interaction, is also influenced by other factors including imaging probe delivery and optical tissue absorption of excitation and emission light.Fluorescence from a second spectrally matched constant (non-activatable) fluorophore on each nanoparticle platform can be used to correct for both probe delivery and tissue absorption. The fluorescence from each fluorophore is separated using fluorescence lifetime methods.

Proteolytic enzyme therapy in evidence-based complementary oncology: fact or fiction?

Systemic enzyme therapy was recently subjected to experimental investigations and to rigorous clinical studies in cancer patients. The designs of the relevant clinical cohort studies followed the guidelines of Good Epidemiological Practice and represent level IIB in evidence-based medicine (EBM). Scientifically sound experimental in vitro and in vivo investigations are far advanced and document promising immunological, anti-inflammatory, anti-infectious, and antitumor/antimetastatic activities of proteolytic enzyme mixtures (containing trypsin, chymotrypsin, and papain) or bromelain. EBM level II clinical studies, which are accepted by the European Union to show safety and efficacy of medical treatments, were performed to evaluate the benefit of complementary systemic enzyme therapy in cancer patients suffering from breast and colorectal cancers and plasmacytoma. These studies demonstrated that systemic enzyme therapy significantly decreased tumor-induced and therapy-induced side effects and complaints such as nausea, gastrointestinal complaints, fatigue, weight loss, and restlessness and obviously stabilized the quality of life. For plasmacytoma patients, complementary systemic enzyme therapy was shown to increase the response rates, the duration of remissions, and the overall survival times. These promising data resulted in an "orphan drug status" designation for a systemic enzyme product, which should motivate further studies on this complementary treatment.

Trypsin in colorectal cancer: molecular biological mechanisms of proliferation, invasion, and metastasis

Trypsin is involved in colorectal carcinogenesis and promotes proliferation, invasion, and metastasis. Although a well-known pancreatic digestive enzyme, trypsin has also been found in other tissues and various cancers, most importantly of the colorectum. Moreover, colorectal cancers with trypsin expression have a poor prognosis and shorter disease-free survival. Biological understanding of how trypsin causes cancer progression is emerging. It seems to act both directly and indirectly through a 'proteinase-antiproteinase-system', and by activation of other proteinase cascades. Invasion of the basal membrane by cancer cells may be promoted directly by trypsin digestion of type I collagen. Trypsin activates, and is co-expressed with matrix metalloproteinases (MMPs), which are known to facilitate invasion and metastasis. MMP-2, MMP-7, and MMP-9 are co-expressed together with trypsin and seem to be of particular importance in proliferation, progression, and invasion. MMPs may play a role in both conversion from adenoma to carcinoma, and in the initiation of invasion and metastasis. Co-segregation of trypsin and MMPs within the tumour environment is important for the activation of MMPs, and may explain the deleterious effect of trypsin on prognosis in colorectal cancer. Trypsin and proteinase-activated receptor 2 (PAR-2) act together in an autocrine loop that promotes proliferation, invasion, and metastasis through various mechanisms, of which prostaglandin synthesis is important. Stimulated by trypsin, both MMP and PAR-2 may activate the mitogenic MAPK-ERK pathway through activation of the epidermal growth factor receptor. Experimental trypsin inhibition is feasible but not very effective, and trypsin as a target for clinical therapy is unlikely to be successful owing to its universal distribution. However, as the pathways of trypsin and co-activated protein cascades emerge, biological understanding of colorectal carcinogenesis will be further illuminated and may pave the way for prognosticators, predictors, and novel targets of therapy.

Tumour-associated trypsin inhibitor, carcinoembryonic antigen and acute-phase reactant proteins CRP and alpha1-antitrypsin in patients with gastrointestinal malignancies

OBJECTIVES

Elevated serum tumour-associated trypsin inhibitor (TATI) levels have been observed in association with malignancy or inflammation. The aim of our study was to evaluate the role of TATI in gastric and colorectal cancer.

DESIGN AND METHODS

In preoperative serum samples, we measured TATI, carcinoembryonic antigen (CEA), C-reactive protein (CRP) and alpha(1)-antitrypsin (AAT).

RESULTS

Elevated levels of TATI were observed in 50% and 41.7% of patients with gastric and colorectal cancer. Elevated levels of TATI were observed only in 8% of patients with benign gastrointestinal malignancies (92% specificity). Elevated levels of CEA were observed in 25% and 24.4% of patients, respectively. The total positivity of CEA and TATI (with at least one marker positive) was 62.5% and 57%, respectively. Spearman's test has shown a statistically significant correlation among serum TATI, CRP and AAT levels (P < 0.01).

CONCLUSIONS

In gastrointestinal cancer, TATI can be used as a complementary tumour marker in addition to CEA. Regulation of TATI synthesis resembles that of acute-phase reactant proteins.

Systemic enzyme therapy in oncology: effect and mode of action

Plant extracts with a high content of proteolytic enzymes have been used for a long time in traditional medicine. Besides proteolytic enzymes from plants, 'modern' enzyme therapy additionally includes pancreatic enzymes. The therapeutic use of proteolytic enzymes is partly based on scientific studies and is partly empirical. The aim of the current review is to provide an overview of clinical trials of systemic enzyme therapy in oncology, and to discuss the evidence for their possible mechanisms of action. Clinical studies of the use of proteolytic enzymes in oncology have mostly been carried out on an enzyme preparation consisting of a combination of papain, trypsin and chymotrypsin. This review of these studies showed that enzyme therapy can reduce the adverse effects caused by radiotherapy and chemotherapy. There is also evidence that, in some types of tumours, survival may be prolonged. The beneficial effect of systemic enzyme therapy seems to be based on its anti-inflammatory potential. However, the precise mechanism of action of systemic enzyme therapy remains unsolved. The ratio of proteinases to antiproteinases, which is increasingly being used as a prognostic marker in oncology, appears to be influenced by the oral administration of proteolytic enzymes, probably via an induction of the synthesis of antiproteinases. Furthermore, there are numerous alterations of cytokine composition during therapy with orally administered enzymes, which might be an indication of the efficacy of enzyme therapy. Effects on adhesion molecules and on antioxidative metabolism are also reviewed.

The molecular biology of colorectal cancer development and the associated genetic events

Colorectal carcinoma remains the second most common malignancy in the western world. Mortality has remained stable despite advances in surgical and adjuvant radio- and chemotherapy regimens. This has renewed interest in the understanding of the basic principles of the molecular biology of colorectal carcinogenesis. The condition is characterised by multiple mutations in common oncogenes and tumour suppressor genes encompassing the inherited conditions familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. The latter is characterised by genomic instability due to mismatch repair gene defects. These conditions and the role of the tumour protease systems, e.g. the plasminogen activation system and the matrix metalloproteinases, involved in the degradation of the extracellular matrix, provide an ideal role model for the study of carcinogenesis. The understanding and future application of these basic mechanisms, combined with the recent innovative work on the potential prophylactic role of COX2 inhibition, may provide further insight in the ultimate quest for a 'cure'. In the long-term, this concept may have to be achieved at the molecular level.