Expression of pancreatic secretory trypsin inhibitor (PSTI) in colorectal cancer

Abstract

Summary We examined the expression of pancreatic secretory trypsin inhibitor (PSTI) in colorectal cancer by immunohistochemical staining using an anti-PSTI antiserum, an in situ hybridisation technique utilising sulphonated PSTI cDNA probe, and a Northern blot hybridisation method, using a 32P-labelled PSTI Pancreatic secretory trypsin inhibitor (PSTI) consists of a single polypeptide chain, and is known to be a specific trypsin inhibitor in the pancreas. Its physiological role has been considered to prevent the premature activation of trypsin in the pancreatic acini and ducts (Kazal et al., 1948). However, PSTI has also been demonstrated in various malignant cell lines and tissues, including pancreatic cancer, lung cancer, gynaecological cancer, and gastric cancer (Higashiyama et al., 1990;Ogata, 1988;Ogawa et al., 1987;Tomita et al., 1987;Ueda et al., 1989); the physiological role of PSTI in neoplastic tissue remains unknown. Nevertheless, several investigators have recently shown that PSTI may have functions other than the inhibition of trypsin activity, such as growth factor action (Niinobu et al., 1986;Ogawa et al., 1985Ogawa et al., , 1987. In fact, we have shown that the expression of PSTI in gastric cancer may possibly be associated with tumour growth and progression (Higashiyama et al., 1990).Although it has been reported that PSTI may be expressed in villous adenoma of the colon (Bohe et al., 1986;Tomita et al., 1987), there has been-u-study of the expression of PSTI in colorectal cancer, except for the preliminary report (Ogawa et al., 1987). In the present study, we demonstrate that colorectal cancer may also express PSTI, not only by immunohistochemical analysis for detection at the product level but also by in situ hybridisation and Northern blot hybridisation for detection at the transcriptional level. In addition, the possible biological and clinical significance of PSTI expression in colorectal cancer is also discussed. Materials and methods Tissue preparationThe tissues were supplied from surgical specimens resected at the 2nd Dept of Surgery, Osaka University Hospital. Preparation of anti-PSTI antiserum and immunohistochemical study Anti-PSTI antiserum used in this study was produced in rabbits as previously described (Kitahara et al., 1980). Its sensitivity and specificity were also confirmed by radioimmunoassay.Immunohistochemical study was performed according to a modified method of Hsu et al. (1981). Briefly, sections were dewaxed in xylene, rehydrated with a series of ethanol solutions, and endogenous peroxidase activity was blocked using 0.3% hydrogen peroxide in methanol for 30 min. After immersion in 3% normal goat serum for 30 min, in order to block non-specific binding, the sections were incubated with primary anti-PSTI antiserum at a dilution of 1:400 overnight at 4°C, and subsequently with biotinylated goat anti-rabbit IgG (Vector) and avidin-biotin peroxidase complex (Vectastain ABC kit, Vector) for 30 min each at room temperature. They were washed in PBS between each incubation...

Hepatitis B and Hepatitis C Virus Replication Upregulates Serine Protease Inhibitor Kazal, Resulting in Cellular Resistance to Serine Protease-Dependent Apoptosis

“…The expansion of these residual oncogenic cells could then lead to cancer recurrence. Since SPIK is also elevated in other cancers (16,19,24,31,40,41), it is possible that this could be a common process of cancer formation. How HBV/HCV triggers the overexpression of SPIK is still unclear.…”

“…SPIK, which is also known as SPINK1, TATI (tumor-associated trypsin inhibitor), and PSTI (pancreas secretory trypsin inhibitor) (8,24,38), was first discovered in the pancreas as an inhibitor of autoactivation of trypsinogen (9). The expression of SPIK in normal tissue is limited or inactivated outside the pancreas, but expression of SPIK is elevated in numerous cancers, such as colorectal tumors, renal cell carcinoma, gastric carcinoma, and intrahepatic cholangiocarcinoma (ICC) (16,19,24,31,40,41). It remains unknown, however, what role SPIK may play in cancer formation and development.…”

SPINK1 Status in Colorectal Cancer, Impact on Proliferation, and Role in Colitis-Associated Cancer

“…SPINK1 is also produced in cancers of the colon (15,16), lung (17,18), liver (19), breast (20), prostate (21), and pancreas (20,22). In colon cancer, Gouyer and colleagues (23) identified and characterized SPINK1 as a major proinvasive secreted factor from the conditioned medium of HT-29 5M21 human colon cancer cells, which express a spontaneous invasive phenotype.…”

Tumor-associated trypsin inhibitor in normal and malignant renal tissue and in serum of renal-cell carcinoma patients

“…TATI is synthetized by several tumors, e.g., ovarian (Halila et al, 1988), colonic (Higashiyama et al, 1990b), gastric (Higashiyama et al, 1990a) and hepatocellular carcinomas (Ohmachi et al, 1993). It is also secreted by several tumor cell lines derived from various cancer tissues, and elevated serum levels may occur in many cancers Halila et al, 1988).…”