| Objective: Colorectal cancer is one of the common malignant tumorswith high morbidity and mortality, and has brought heavy burdens to thesociety as well as families because of its large patient population. The etiologyand pathogenesis of colorectal cancer is not fully understood yet till now, andit is believed that the etiology possibly results from a combined effect ofenvironmental and genetic factors, while the pathogenesis may be related tosuch factors as oncogenes and tumor-suppressor genes mutation, genepolymorphism, and abnormal signal transduction pathways. Many studieshave shown that microRNAs are directly related to the occurrence, evolutionand metastasis of colorectal cancer. Previous researches employed gene chipsto the high-throughput screening of miRNAs in colorectal cancer tissues, andfound that miR-10b and miR-125a-5p had a low expression, which may berelevant to the occurrence and evolution of colorectal cancer. Therefore, thepresent study took miR-10b and miR-125a-5p as research indicators, andadopted real-time quantitative reverse transcription-PCR to detect theexpression levels of the two indicators in colorectal cancer tissues, adjacentnormal tissues and colorectal cancer cell strains, and then analyzed its clinicalsignificance.Methods:1Tissue blocks including the tumor and the distant normal tissues wereobtained from37patients (21males and16females, aged from31to83, witha mean age of69) with primary colorectal cancer who underwent surgicalresection in the First Hospital of Hebei Medical University in the period ofJune2012–June2013. No patient had received radiotherapy, chemotherapy orimmunotherapy treatment before the surgical resection. The patients’pathologic features (such as sex, age, tumor location, and Dukes’ stage, histological type, lymph nodes status, invasion depth, tumor differentiation,and distant metastasis etc.) were obtained on their informed consent. Eachspecimen was obtained from the colorectal cancer tissue and the upper/lowerborder of the adjacent normal tissue.2Trizol Method was employed to extract total RNA of the colorectalcancer tissue and the normal tissue. Reverse transcription was conductedaccording to the retroviruses kit instructions of American GeneCopoeiaCompany. RT-qPCR technique was used to detect the expressions ofmiRNA-10b and miR-125a-5p in colorectal cancer tissues and normal mucosatissues adjacent based on the instructions of the primers made byGeneCopoeia Company. The reaction conditions were as follows:95℃degeneration for10minutes, and then the process of95℃×10s,60℃×30sand72℃*×10s were circulated40times to take the average after3repetitions. This study used2-ΔΔCTmethod, in which ΔCT stood for the CTdifference of target genes and CTU6, and ΔΔ CT, the ΔCT difference of ΔCTcarcinoma tissues and normal tissues.38kinds of colorectal cancer cell strains (a gift from Professor Yu Junfrom Institute of Digestive Disease, Chinese University of Hong Kong)–Caco-2, DLD1, HCT116, HT29, LOVO, SW480, SW620, SW1116–werechosen for cell culturing. Sub culturing was conducted every one or two days,and the cells were collected to extract RNA when they grew to as much as106~107. RT-PCR method was applied to detect the expressions ofmiRNA-10b and miR-125a-5p in normal mucosa tissues and in the8kinds ofcolorectal cancer cell strains.4Statistical treatment: The experiment data were analyzed by usingSPSS19.0and presented by medians (quartile range). The paired samples andindependent samples between groups were tested by Wilcoxon andMann-Whitney U respectively, and the difference (P <0.05) was statisticallysignificant.Results:1. Expressions of miR-10b and miR-125a-5p in colorectal cancer tissues and their clinical significance1.1The expression quantities of miR-10b in the carcinoma tissues and normalmucosa tissues of the37patients were0.024(0.009,0.061) and0.090(0.043,0.335) respectively, and there was significant difference statistically betweenthem (Z=-4.428, P=9.519E-6).1.2There was no statistical significance in all the paired comparisons ofmiR-10b expression quantities among groups in terms of genders (P=0.195),groups of age (<69and≥69)(P=0.772), groups of tumor location (P=0.619),groups of invasion depth (P=0.695), groups of Dukes’ stage (P=0.797),groups of histological type (P=0.667), and groups of educational level(P=0.395). The relative expression quantity of miR-125a-5p was0.053(0.028,0.423) in poorly differentiated group, and0.441(0.155,0.779) inhighly-and-intermediately differentiated group. And P was0.037in thecomparison of the two, which was statistically significant. There was nostatistical significance in all the paired comparison of miR-125a-5p expressionquantity among groups in terms of genders (P=0.195), groups of age (<69and≥69)(P=0.772), groups of tumor location (P=0.619), groups of invasiondepth (P=0.695), groups of lymphatic metastasis (P=0.891), groups of Dukes’stage (P=0.940), groups of histological type (P=0.590), and groups of distantmetastasis (P=0.832).Expressions of miR-10b and miR-125a-5p in colorectalcancer cell strains.2. The expressions of miR-10b in colorectal cancer cell strains were lowerthan those of all normal mucosa tissues. All the other7kinds of cells hadstatistical significance (P<0.05) except HT29. The expressions ofmiR-125a-5p in colorectal cancer cell strains were all significantly lower thanthose of all normal mucosa tissues (P<0.05).Conclusions:1The expressions of miR-10b in colorectal cancer cells weresignificantly lower than those of adjacent normal tissues, which indicated thatmiR-10b may play a role of tumor suppressing in the occurrence andevolution of colorectal cancer. The expressions of miR-10b had no relation to clinic pathologic features and required further studies about its effects oncolorectal cancer.2The expressions of miR-125a-5p in colorectal cancer cells were allsignificantly lower than those of all normal mucosa tissues and related to thedifferentiation degrees, which indicated that miR-125a-5p may play a role oftumor suppressing in the occurrence and evolution of colorectal cancer, andmay have some impact on prognosis of colorectal cancer.3The expressions of miR-10b and miR-125a-5p were all low in the8kinds of colorectal cancer cell strains, which were consistent with theexpressions in tumor tissues. And it’s further confirmed that they both havenegative control response on the occurrence of colorectal cancer. |
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