| Cathepsins forms a large super-family of proteinase splitting peptide bond composed different type based on their different typecatalytic center, mainly including lysosome cysteine proteins(such as cathepsin B, L), aspartate proteinases (such as catepsin D, E), serine proteinases(such as cathepsin A,G and R). Cathepsin L(CL) is a member of lysosome cysteine proteins. Being the major excreted protein, CL distributes widely in human various kinds of normal and tumor tissue. The role of CL is extremely extensive, CL participates in many sorts of physiologic function such as osmogen activation, spermatogenesis, oogenesis, antigen processing, bone matrix absorption, central nervous system development and maturity and so on and pathological process. Because of the change of transcription, translation, modification, position fixing, maturity and pH and abnormality of interaction between CL and its inhibitors, CL play a role in the growth and development of many kinds of disease, such as invasion and metastasis of tumor, arthrositis, osteoporosis, Alzheimer's disease, multiple sclerosis and many chronic inflammation. For the past few years, mass researches indiicate CL shows high expressions in many kinds of malignant tumors such as carcinoma of prostate, melanoma, gastric cancer, colorectal and pancreatic carcinoma and so on. Many evidence demonstrated that CL participated not only the invasion and metastasis of malignant rumors and correlated with prognosis, but also drug resistance of tumor, immortalization, cachexia, apoptosis, immunomodulation etc.Cystatin B(CSTB) is the endogenous inhibitor of lysosomal cysteine proteinase, such as cathepsin B, H, L and S, mainly inhibits CL. Prolease enzymatic activity is regulated by many factors, including protease inhibitors. They maintain dynamic equilibrium under physiological condition. The imbalance between cysteine proleases activity and cysteine prolease inhibitor activity contributes to the invasion and metastasis of malignant cells phenotype. Many researches showed that the down-expression of CSTB significantly correlated with tumor node metastases and progression.Colorectal cancer is one of the common malignant tumors. Its incidence is rising with global population aging and the devement of living stand, and increased by 2% per year from 2000 to 2005 according to statistics. It already severely impacted peoples' health. Investigate the mechanism of the invasion and metastasis of colorectal cancer has been one of research hot spots because invasion and metastasis is main death reasons of colorectal cancer patients. There are few domestic and foreign reports involving how CL and CSTB and its relationship with the invasion and metastasis of colorectal cancer as yet.CL protein and mRNA of colorectal cancer issues and its' adjacent normal mucosa tissues of 45 cases were measured using immunohistochemistry and in situ hybridization method; expression of CSTB protein is investigated by immunohistochemical methods. This research further explored the mechanisms of invasion and metastasis of colorectal cancer and might provides theory foundation for blocking invasion and metastasis of colorectal cancer.Methods1. Using the technology of immunohistochemistry SP to detect the expression of CL and CSTB in the 45 cases of colorectal cancer and its' adjacent normal mucosa tissues respectively.2. Using the technology of in situ hybridization to indicate the gene of CL in 45 cases of colorectal cancer, and tumor-adjacent normal colorectal tissues respectively.3. Statistical analysis: All the dates were analyzed by SPSS 11.0 statistical package; the count information calculated the positive rate. The comparison of positive rates were used the Chi-square; the relation of two variables was analyzed by the spearman level correlation analysis. Size of test is a=0.05.Results1. The results of in situ hybridization demonstrated that the positive rates of mRNA expression of CL in the carcinoma tissues and tumor-adjacent normal tissues were 77.8%(35/45), 15.6%(7/45)respectively; the rates in the 18 cases of well-differentiat- ed tissues and 27 cases of moderately/poorly-differentiated tissues were 61.1%(11/18), 88.9%(24/27)respectively; The posive rates of expression of CL mRNA in the carcinoma tissues of Dukes stage A, B and Dukes stage C, D were 65.4%(17/26), 94.7%(18/19)respectively. There was significant difference between the two groups(P <0.05).2. The results of immunohistochemistry demonstratesd that the positive rates of CL protein expression in tumor and normal tissues were 82.2%(37/45), 24.4%(11/45) respectively. There was significant difference between the two groups(P < 0.05). CL stained positive in 66.7%(12/18) of cases of well-differentiated tissues and 92.6% (24/27) of cases of moderately /poorly-differentiated tissues respectively. The positive rates was 69.2 %(18/26) in the 26 cases of Dukes stage A, B and 100 %( 19/19) in the 19 cases of Dukes stage C, D respectively. Statistical analysis showed a significant correlation between CL expression and rumor grading (P < 0.05) and between CL and Dukes stage (P < 0.05).3. The positive rates of CSTB expression in tumor and normal tissues were 40 %(18/45), 66.7 %(30/45) respectively. There was a significant difference between the two groups. The expression of CSTB was lower in poorly differenated cases 22.2%(6/27) than that of well differentiated 66.7%(12/18).The positive rates was 53.8%(14/26) in the cases of Dukes stage A, B and 21.1%(4/19) in the cases of Dukes stage C, D respectively. There was statistical signicance (P < 0.05).4. Statistical analysis showed that CL protein expression correlated with mRNA level in tumor cells, and the expression of CL was negative correlation with that of CSTB (P<0.05).Conclusions1. The expression of CL mRNA and protein in colorectal cancer tissues were higher than that in normal tissues; The expression of CL mRNA and protein in moderately/ poorly-differentiated and Dukes stage C, D tissues of colorectal cancer were higher than that in well-differentiated and Dukes stage A, B tissues. While the expression of CSTB protein were lower than that in normal tissues; the expression of CSTB in moderately/poorly-differentiated and in Dukes stage C, D tissues of colorectal cancer were lower than that in well-differentiated and Dukes stage A, B tissues. They indicated that CL and CSTB likely participated the occurrence, invasion and metastasis of colorectal cancer.2. CL protein expression correlated with mRNA level in colorectal cancer, which indicated that the abnormality expression of CL likely occurred in transcriptional level.3. The expression of CL in colorectal cancer was negative correlation with the expression of CSTB. It indicated that the imbalance of CL and CSTB might participate occurrence and development, invasion and metastasis of colorectal cancer. |
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