Yongfen Min

Overexpression of the matrix serine protease (MSP) trypsin has been implicated in tumour growth, invasion, and metastasis. The objective of this study was to clarify the clinicopathological and prognostic significance of trypsin expression in colorectal cancer. This study analysed the association between immunohistochemically detected trypsin expression in colorectal cancer and clinicopathological characteristics, and investigated whether trypsin is a predictor of recurrence and/or survival. Trypsin immunoreactivity was more intense at the invasive front than in the superficial part of the tumour. Sections with immunostaining signals in more than 30% of carcinoma cells at the invasive front, which were observed in 48 cases (48%), were judged to be positive for trypsin. Trypsin positivity was significantly correlated with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advanced pathological tumour-node-metastasis (TNM) stage, and recurrence. Patients with trypsin-positive carcinoma had significantly shorter overall and disease-free survival periods than did those with trypsin-negative carcinoma. Trypsin retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors. It is well known that trypsin activates matrilysin (matrix metalloproteinase-7), which plays an important role in colorectal cancer progression. Patients with concordant overexpression of trypsin and matrilysin at the invasive front, in which they were often co-localized, had the worst prognosis. Trypsinogen-1-transfected HCT116 colon cancer cells showed not only trypsin activity, but also active matrilysin activity and were more invasive in vitro than mock-transfected HCT116 cells. These results suggest that trypsin plays a key role in the progression of colorectal cancer. Detection of trypsin expression as well as matrilysin is useful for the prediction of recurrence in and poor prognosis of colorectal cancer patients.

Pancreatic cancer is one of the most lethal malignant tumors. Insulin-like growth factor (IGF)-I receptor (IGF-Ir) signaling is required for maintenance of growth and tumorigenicity of many tumors, but this pathway has not been well studied in pancreatic cancer. We have shown previously successful therapy in colorectal and lung cancer xenograft models using recombinant adenoviruses expressing dominant negative IGF-I receptors. In this study, we sought to better dissect the mechanism of action of this virus and determine whether IGF-Ir targeted adenoviruses represent potentially effective therapeutics for human pancreatic cancer cells. Truncated IGF-I receptors (IGF-Ir/dn; 482 and 950 amino acids long, respectively, IGF-Ir/482st and IGF-Ir/950st) that function as dominant negative inhibitor were cloned into recombinant adenoviruses and used to treat human pancreatic cancer cells. We assessed the effect of IGF-Ir/dn on signaling blockade, growth, stress response, chemotherapy, radiation-induced apoptosis, and in vivo therapeutic efficacy in xenografts. IGF-Ir/dn expression suppressed tumorigenicity both in vitro and in vivo and up-regulated stressor-induced apoptosis. It effectively blocked both IGF-I and IGF-II-induced activation of Akt-1. IGF-Ir/dn expression increased radiation and chemotherapy-induced apoptosis, and the combination therapy of IGF-Ir/dn with chemotherapy was very effective against tumors in mice. In an i.p. model, IGF-Ir/dn therapy reduced dissemination and prolonged survival times. Moreover, IGF-Ir/482st was more effective than IGF-Ir/950st because of its bystander effect. The antitumor activity of IGF-Ir/dn is mediated through inhibition of Akt-1 and enhances the efficacy of chemotherapy. Adenovirus-IGF-Ir/482st may be a useful anticancer therapeutic for pancreatic cancer.

Expression of E1AF/PEA3 (ETV4), an ets family transcription factor, has been implicated in the invasive potential of several cancer cell lines through induction of matrix metalloproteinase (MMP) expression. The aim of this study was to examine E1AF mRNA expression and to determine whether it is correlated with progression of, and/or MMP expression in, human colorectal cancer. Using the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), 100 colorectal cancer tissues were analysed for E1AF mRNA expression. Expression of ER81 (ETV1) and ERM (ETV5), the other two members of the PEA3 subfamily, and Ets-1 and Ets-2 was also analysed. The results were correlated with clinicopathological characteristics and MMP expression. Immunohistochemical analysis and an in vitro invasion assay were also performed. E1AF mRNA expression was detected in 62% of the 100 colorectal cancer tissues, but was undetectable or only faintly detected in adjacent non-tumour tissues. E1AF mRNA was detected in all of the ten liver metastases from colorectal cancers. E1AF expression correlated significantly with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advance in pathological tumour-node-metastasis stage, and recurrence. Patients with E1AF-positive tumours had significantly shorter overall and disease-free survival periods than did those with E1AF-negative tumours (p < 0.0001 and p < 0.0001, respectively). E1AF expression retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors (p = 0.0066 and p = 0.0109, respectively). Among the MMPs analysed, expression of MMP-1 and matrilysin correlated significantly with E1AF expression. In contrast, expression of ER81 and ERM did not correlate with clinicopathological characteristics or the expression of these MMPs. Immunohistochemical expression of E1AF was predominantly observed at the invasive front, where the expression of MMP-1 and matrilysin and nuclear beta-catenin expression were often co-localized. Antisense E1AF-transfected HT-29 colon cancer cells expressed reduced levels of MMP-1 and matrilysin and were less invasive in vitro than neo-transfected HT-29 cells. The results of this study suggest that E1AF, the expression of which is closely correlated with the expression of MMP-1 and matrilysin, plays a key role in the progression of colorectal cancer.

Insulin-like growth factor (IGF)-I receptor (IGF-Ir) signaling is required for tumorigenicity and progression of many tumors but this pathway has not been well studied as a prognostic factor or potential therapeutic target in esophageal squamous cell carcinoma (ESCC). In this paper, the association between the expression of IGF-Ir and IGF-II ligand and prognosis was investigated immunohistochemically in 100 surgically resected ESCC. We then assessed the therapeutic effect of blocking IGF receptor signaling using dominant negative IGF-Ir (IGF-Ir/dn) in ESCC in vitro. Expression of IGF-Ir and IGF-II were detected in 60 and 50% of tumors, respectively, and were associated with invasion depth, metastasis, advanced tumor stage and recurrence. Patients with tumors expressing both IGF-Ir and IGF-II had a significantly shorter survival than those expressing either alone or neither in both single and multivariate analysis. IGF-Ir/dn suppressed proliferation and motility as well as upregulating chemotherapy-induced apoptosis through blocking ligand-induced Akt activation. We propose that detection of IGF-Ir/IGF-II in ESCC may be useful for the prediction of recurrence and poor prognosis and for selecting patients for IGF-Ir-targeted therapy. Therapeutic blockade of IGF-Ir may be a useful anticancer therapeutic for ESCC.