Differential expression of mucin 1 and mucin 2 in colorectal cancer

AIM To determine tissue expression(mRNA, protein) of two types of mucins [mucin 1(MUC1) and mucin 2(MUC2)] in patients with colorectal cancer(CRC).METHODS Expression of membrane-bound mucin(MUC1) and secretory mucin(MUC2) in CRC(mRNA, protein) were analyzed in tissue material including fragments of tumorsobtained from CRC patients(n = 34), and fragments of normal colorectal tissue from the same patients(control). The analysis was conducted using real-time quantitative polymerase chain reaction(RT-qPCR)(transcripts), immunohistochemistry(IHC)(apomucins), and the modern approach for morphometric analysis of IHC reaction(HSV filter software). Results on tissue expression of both mucins(mRNA, protein) were compared to histological alterations in colorectal cancer samples and correlated with selected clinical data in the patients. The statistical analysis was conducted using Statistica PL v. 12.0 software.RESULTS Significantly higher expression of the MUC1 mRNA in the CRC, compared with the control and the borderline correlation of mRNA expression with MUC1 protein levels in colorectal samples was observed. The expression of apomucins concerned cell membranes(MUC1) and cytoplasm(MUC2) and occurred both in control tissues and in most cancerous samples. There were no significant relationships between MUC1(mRNA, protein) and the clinicopathological data of patients. MUC2 protein expression was significantly lower as compared to the control, while MUC2 mRNA expression was comparable in both groups. The MUC1/MUC2 ratio was significantly higher in CRC tissues than in the control. The higher expression of MUC2 was a feature of mucinous CRC subtypes, and characterized higher histological stage of tumors. Negative correlations have been obtained between MUC2 and the Ki-67 antigen, as well as between MUC2 and p53 protein expressions in CRC.CONCLUSION A combination of tissue overexpression of MUC1, reduced MUC2 expression, and high ratio of MUC1/MUC2 is a factor of poor prognosis in CRC patients. MUC2 tissue expression allows to differentiate mucinous and nonmucinous CRC subtypes.

Insulin-like growth factor-1 mRNA isoforms and insulinlike growth factor-1 receptor mRNA expression in chronic hepatitis C

AIM: to evaluate the expression of different insulinlike growth factor(IGF)-1 mRNA isoforms and IGF-1 receptor(IGF-1R) mRNA in hepatitis C virus(HCV)-infected livers. METHODS: Thirty-four liver biopsy specimens from chronic hepatitis C(CH-C) patients were obtained before anti-viral therapy. Inflammatory activity(grading) and advancement of fibrosis(staging) were evaluated using a modified point scale of METAVIR. The samples were analyzed using quantitative real-time PCR technique. From fragments of liver biopsies and control liver that were divided and ground in liquid nitrogen, RNA was isolated using RNeasy Fibrous Tissue Mini Kit according to the manufacturer's instruction. Expression levels of IGF-1 mRNA isoforms(IGF-1A, IGF-1B, IGF-1C, P1, and P2) and IGF-1R mRNA were determined through normalization of copy numbers in samples as related to reference genes: glyceraldehyde-3-phosphate dehydrogenase and hydroxymethylbilane synthase. Results on liver expression of the IGF-1 mRNA isoforms and IGF-1R transcript were compared to histological alterations in liver biopsies and with selected clinical data in the patients. Statistical analysis was performed using Statistica PL v. 9 software. RESULTS: The study showed differences in quantitative expression of IGF-1 mRNA variants in HCV-infected livers, as compared to the control. Higher relative expression of total IGF-1 mRNA and of IGF-1 mRNAs isoforms(P1, A, and C) in HCV-infected livers as compared to the control were detected. Within both groups, expression of the IGF-1A mRNA isoform significantly prevailed over expressions of B and C isoforms. Expression of P1 mRNA was higher than that of P2 only in CH-C. Very high positive correlations were detected between reciprocal expressions of IGF-1 mRNA isoforms P1 and P2(r = 0.876). Expression of P1 and P2 mRNA correlated with IGF-1A mRNA(r = 0.891; r = 0.821, respectively), with IGF-1B mRNA(r = 0.854; r = 0.813, respectively), and with IGF-1C mRNA(r = 0.839; r = 0.741, respectively). Expression of IGF-1A mRNA significantly correlated with isoform B and C mRNA(r = 0.956; r = 0.869, respectively), and B with C isoforms(r = 0.868)(P < 0.05 in all cases). Lower expression of IGF-1A and B transcripts was noted in the more advanced liver grading(G2) as compared to G1. Multiple negative correlations were detected between expression of various IGF-1 transcripts and clinical data(e.g., alpha fetoprotein, HCV RNA, steatosis, grading, and staging). Expression of IGF-1R mRNA manifested positive correlation with grading and HCV-RNA. CONCLUSION: Differences in quantitative expression of IGF-1 mRNA isoforms in HCV-infected livers, as compared to the control, suggest that HCV may induce alteration of IGF-1 splicing profile.