Hisae Iinuma

PURPOSE: Using multiple genetic markers, including cancer stem-like cells, we evaluated the clinical significance of circulating tumor cells (CTCs) as a prognostic factor for overall survival (OS) and disease-free survival (DFS) in the peripheral blood (PB) of patients with colorectal cancer (CRC) who had undergone curative surgery. PATIENTS AND METHODS: In a multi-institutional study, 735 patients with CRC were assigned to a retrospective training set (n = 420) or prospective validation set (n = 315). CTCs that expressed carcinoembryonic antigen (CEA), cytokeratin (CK) 19, CK20, and/or CD133 (CEA/CK/CD133) mRNA in PB were detected using real-time reverse transcription polymerase chain reaction assay. RESULTS: In the training sets, OS and DFS of patients who were positive for CEA/CK/CD133 were significantly worse than those of patients who were negative for these markers (P < .001). At each staging analysis, OS and DFS of patients with Dukes' stage B or C cancer who were positive for CEA/CK/CD133 were significantly worse than those of patients who were negative for these markers (P < .003 and P < .001 in Dukes' stage B; P < .001 in Dukes' stage C). In contrast, in patients with Dukes' stage A, no significant differences were seen between patients who were positive for these markers and those who were negative. Cox multivariate analysis demonstrated that CEA/CK/CD133 was a significant prognostic factor for OS (hazard ratio [HR], 3.84; 95% CI, 2.41 to 6.22; P < .001) and DFS (HR, 3.02; 95% CI, 1.83 to 5.00; P < .001). In particular, in patients with Dukes' stage B and C cancer, CEA/CK/CD133 demonstrated significant prognostic value. In validation sets, similar results were confirmed in patients with Dukes' stage B and C cancer. CONCLUSION: In patients with Dukes' stage B and C CRC who require adjuvant chemotherapy, detection of CEA/CK/CD133 mRNA in PB is a useful tool for determining which patients are at high risk for recurrence and poor prognosis.

Abstract Circulating tumor cells (CTC) in blood have attracted attention both as potential seeds for metastasis and as biomarkers. However, most CTC detection systems might miss epithelial–mesenchymal transition (EMT)-induced metastatic cells because detection is based on epithelial markers. First, to discover novel markers capable of detecting CTCs in which EMT has not been repressed, microarray analysis of 132 colorectal cancers (CRC) from Japanese patients was conducted, and 2,969 genes were detected that were overexpressed relative to normal colon mucosa. From the detected genes, we selected those that were overexpressed CRC with distant metastasis. Then, we analyzed the CRC metastasis-specific genes (n = 22) to determine whether they were expressed in normal circulation. As a result, PLS3 was discovered as a CTC marker that was expressed in metastatic CRC cells but not in normal circulation. Using fluorescent immunocytochemistry, we validated that PLS3 was expressed in EMT-induced CTC in peripheral blood from patients with CRC with distant metastasis. PLS3-expressing cells were detected in the peripheral blood of approximately one-third of an independent set of 711 Japanese patients with CRC. Multivariate analysis showed that PLS3-positive CTC was independently associated with prognosis in the training set (n = 381) and the validation set [n = 330; HR = 2.17; 95% confidence interval (CI) = 1.38–3.40 and HR = 3.92; 95% CI = 2.27–6.85]. The association between PLS3-positive CTC and prognosis was particularly strong in patients with Dukes B (HR = 4.07; 95% CI = 1.50–11.57) and Dukes C (HR = 2.57; 95% CI = 1.42–4.63). PLS3 is a novel marker for metastatic CRC cells, and it possesses significant prognostic value. Cancer Res; 73(7); 2059–69. ©2012 AACR.

OBJECTIVE: The clinical significance of microRNA-21 (miR-21) and miR-155 in colorectal cancer (CRC) patients remains elusive. In this study, we established the prognostic value of miR-21 and miR-155 using clinical samples from CRC patients. Furthermore, relationships between these microRNAs and target genes (PDCD4 and TP53INP1 mRNAs) were examined. METHODS: miR-21 and miR-155 expression was assessed in tumor tissue and in adjacent normal tissue of 156 CRC patients by TaqMan MicroRNA assays, and PDCD4 and TP53INP1 mRNA levels were measured by quantitative real-time reverse transcriptase PCR (RT-PCR). RESULTS: High miR-21 expression was significantly associated with venous invasion, liver metastasis and tumor stage, and high miR-155 expression was significantly correlated with lymph node metastases. The overall (OS) and disease-free survival (DFS) rates of patients with high miR-21 expression were significantly worse than those of patients with low miR-21 expression. The OS and DFS of patients with high miR-155 expression were also significantly worse than those in patients with low miR-155 expression. miR-21 and miR-155 expression levels in CRC tissue were independent prognostic factors for OS and DFS. Significant inverse correlations were demonstrated between miR-21 and PDCD4 mRNA, and miR-155 and TP53INP1 mRNA. CONCLUSION: Increases in miR-21 and miR-155 expression may represent effective biomarkers for the prediction of a poor prognosis.

Peritoneal dissemination in gastric cancer is a common fatal clinical condition with few effective therapies available. We studied the therapeutic effect of a tumor-targeting drug delivery system that uses cisplatin-encapsulated and Tf-conjugated PEG liposomes (Tf-PEG liposomes) in nude mice with peritoneal dissemination of human gastric cancer cells. Small unilamellar Tf-PEG, PEG or DSPC/CH liposomes (bare liposomes) encapsulating cisplatin were prepared by reverse-phase evaporation followed by extrusion. Electron microscopic studies revealed that Tf-PEG liposomes were internalized into tumor cells by receptor-mediated endocytosis. To examine the biodistribution of each liposome and cisplatin level, nude mice were inoculated i.p. with 10(7) MKN45P human gastric tumor cells. On the fourth day after tumor inoculation, (3)H-CHE-labeled and cisplatin-encapsulated Tf-PEG, PEG or bare liposome were inoculated i.p. The Tf-PEG liposome-administered group maintained high liposome and cisplatin levels in ascites and showed a prolonged residence time in the peripheral circulation. Uptake of Tf-PEG liposomes into the liver and spleen was significantly lower than that of bare liposomes. Uptake of Tf-PEG liposomes in disseminated tumor cells of ascites and the greater omentum was significantly higher than that of PEG or bare liposomes and a significant increase in cisplatin levels was observed in these tumor cells. Mice receiving Tf-PEG liposomes 1 and 4 days after the day of tumor inoculation showed significantly higher survival rates compared with those receiving PEG liposomes without Tf, bare liposomes or free cisplatin solution. These results suggest that cisplatin-encapsulated Tf-PEG liposomes may be useful as a new intracellular targeting carrier for treatment of gastric cancer with peritoneal dissemination.

OBJECTIVE: We clarified the predictive and prognostic value of circulating plasma exosomal microRNA-21 (miR-21) in each TNM stage of colorectal cancer (CRC) patients. METHODS: The microRNA (miRNA) profiles of the plasma exosomes, primary tumor tissues, and liver metastasis tissues from the same CRC patients were examined using a microarray. For validation analysis, the plasma exosome samples from 326 CRC patients were measured by TaqMan miRNA assays. RESULTS: In the miRNA microarray analyses, miR-21 showed the highest upregulation in exosomes, primary tumor tissues, and liver metastasis tissues. Significant correlations were demonstrated between exosomal miR-21 and tissue miR-21 levels. As for the relationship to the pathological condition, exosomal miR-21 showed a significant association with liver metastasis and TNM stage. The overall survival (OS) rates and disease-free survival (DFS) rates in high-exosomal-miR-21 patients were significantly worse than those in low-miR-21 patients. Exosomal miR-21 levels were an independent prognostic factor for OS and DFS in CRC patients with TNM stage II or III, and for OS in patients with TNM stage IV. CONCLUSION: Plasma exosomal miR-21 levels are a useful biomarker for the prediction of recurrence and poor prognosis in CRC patients with TNM stage II, III, or IV.