Jin-Tung Liang

miR-103/107 Promote Metastasis of Colorectal Cancer by Targeting the Metastasis Suppressors DAPK and KLF4

Metastasis is the major cause of poor prognosis in colorectal cancer (CRC), and increasing evidence supports the contribution of miRNAs to cancer progression. Here, we found that high expression of miR-103 and miR-107 (miR-103/107) was associated with metastasis potential of CRC cell lines and poor prognosis in patients with CRC. We showed that miR-103/107 targeted the known metastasis suppressors death-associated protein kinase (DAPK) and Krüppel-like factor 4 (KLF4) in CRC cells, resulting in increased cell motility and cell-matrix adhesion and decreased cell-cell adhesion and epithelial marker expression. miR-103/107 expression was increased in the presence of hypoxia, thereby potentiating DAPK and KLF4 downregulation and hypoxia-induced motility and invasiveness. In mouse models of CRC, miR-103/107 overexpression potentiated local invasion and liver metastasis effects, which were suppressed by reexpression of DAPK or KLF4. miR-103/107-mediated downregulation of DAPK and KLF4 also enabled the colonization of CRC cells at a metastatic site. Clinically, the signature of a miR-103/107 high, DAPK low, and KLF4 low expression profile correlated with the extent of lymph node and distant metastasis in patients with CRC and served as a prognostic marker for metastasis recurrence and poor survival. Our findings therefore indicate that miR-103/107-mediated repression of DAPK and KLF4 promotes metastasis in CRC, and this regulatory circuit may contribute in part to hypoxia-stimulated tumor metastasis. Strategies that disrupt this regulation might be developed to block CRC metastasis.

High-frequency microsatellite instability predicts better chemosensitivity to high-dose 5-fluorouracil plus leucovorin chemotherapy for stage IV sporadic colorectal cancer after palliative bowel resection.

The influence of MSI on treatment outcome of colorectal cancers remains unclear and deserves further investigation. We recruited 244 patients with stage IV sporadic colorectal cancers for our study, based on appropriate eligibility criteria. Patients were nonrandomly allocated to 2 treatment groups of either with or without high‐dose 5‐FU plus leucovorin chemotherapy (HDFL, 5‐FU 2,600 mg/m2 leucovorin 300 mg/m2 maximum 500 mg). Each treatment group was further divided into 2 subgroups according to high‐frequency MSI (MSI‐H) status. MSI‐H was defined as the appearance of MSI in at least 2 of the 5 examined chromosomal loci (BAT‐25, BAT‐26, D5S346, D2S123, D17S250). We compared clinicopathologic parameters, p53 overexpression and overall survival between the groups. In addition, 4 subgroups were identified as follows: MSI‐H+HDFL+, n = 35; MSI‐H−HDFL+, n = 134; MSI‐H+HDFL−, n = 17; MSI‐H−HDFL−, n = 58. There was no significant difference of background clinicopathologic data between the HDFL+ and HDFL− treatment groups (p > 0.05). Survival analyses indicated that the patients of subgroup MSI‐H+HDFL+ survived significantly longer than those of subgroup MSI‐H−HDFL+, with median survival times of 24 (95% CI 20.2–27.9) and 13 (95% CI 11.6–14.4) months, respectively (p = 0.0001, log‐rank test). In contrast, in patients without chemotherapy, the prognosis was poor irrespective of MSI status, with median survival times of 7.0 (95% CI 4.6–9.4) and 7.0 (95% CI 6.1–7.9) months in the MSI‐H+HDFL− and MSI‐H−HDFL− subgroups, respectively (p = 0.8205, log‐rank test). MSI‐H cancers responded significantly better to HDFL (p = 0.001), with a mean response rate of 65.71% (95% CI 49.98–81.44%) in subgroup MSI‐H+HDFL+ compared to 35.07% (95% CI 26.99–43.15%) in subgroup MSI‐H−HDFL+. There appeared to be no preferential metastatic site where response to HDFL can be predicted based on the MSI status of the primary tumor. Toxicity to HDFL was similarly minimal between MSI‐H+ and MSI‐H− patients (p > 0.05). Multivariate analysis of all patients further indicated that MSI‐H and chemotherapy were independent favorable prognostic parameters (p < 0.05). Thus, the better prognosis of stage IV sporadic colorectal cancers with MSI‐H may be associated with better chemosensitivity, rather than lower aggressiveness in biologic behavior.

Clinicopathological and molecular biological features of colorectal cancer in patients less than 40 years of age

The aim of the present study was to identify the clinicopathological and molecular biological characteristics of early‐onset colorectal cancers.

Hypermethylation of the p16 gene in sporadic T3N0M0 stage colorectal cancers: association with DNA replication error and shorter survival.

Hypermethylation in the promoter region of the p16 gene was suspected to be involved in the tumorigenesis of colorectal cancers, although its clinical and biological significance remains obscure. In this study, we collected 84 T3N0M0 stage primary colorectal cancers that were curatively resected. The clinicopathologic data were reviewed. p16 hypermethylation was determined by a methylation-specific polymerase chain reaction (PCR). p53 overexpression was detected by immunocytochemistry (ICC). The point mutations in the 12 and 13 codons of the K-ras gene were screened by restriction enzyme analysis. Loss of heterozygosity (LOH) of the DCC (Deleted in Colorectal cancer) gene was examined by PCR using primers of the DCC (18q21) microsatellite marker. The DNA replication error (RER) was examined using 7 microsatellite markers at distinct chromosomal loci. p16 hypermethylation, regarded as an indication of p16 inactivation, was evident in 24 (28.6%) of the tumors. No correlation was found between p16 hypermethylation and various clinicopathologic factors, includinig age, sex, tumor location, tumor size, growth pattern, tumor differentiation, mucin production, vascular and/or lymphatic invasion, lymphocyte infiltration of the tumor, and serum level of carcinoembryonic antigen. There was no association between p16 hypermethylation of K-ras gene mutation, p53 overexpression and LOH of the DCC gene. However, p16 hypermethylation was significantly associated with DNA RER (p = 0.01). Survival analysis revealed a significant survival disadvantage of p16-hypermethylated versus non-p16-hypermethylated tumors (p = 0.0001). These findings indicate that p16 hypermethylation plays a role in the carcinogenesis of a subset of colorectal cancers; and the presence of p16 hypermethylation predicts shorter survival in T3N0M0 stage colorectal cancers.

Prospective evaluation of laparoscopy-assisted colectomy versus laparotomy with resection for management of complex polyps of the sigmoid colon

Laparoscopy-assisted colectomy istechnically feasible, but objective evidence of its benefits remainsscarce. This study was done to evaluate the outcomes and operativestress of laparoscopy-assisted colectomy versus the traditional openmethod in the management of sigmoid complex polyps that cannot besafely or adequately removed by colonofibroscopy. Between January 1997and December 1999, a total of 42 patients were equally randomizedto the laparoscopy group and the laparotomy group by the blockedrandomization method. Three patients randomized to the laparoscopygroup did not complete the trial; therefore 18 patients treated bylaparoscopy-assisted sigmoidectomy and the other 21 treated by the openmethod were prospectively evaluated. These two groups of patients werewell matched in age, gender, symptoms, tumor location, localizationmethod, tumor size, morphology, histopathology, and the accuracy of theclinical diagnosis. Two standardized surgical strategies, thelateral-to-medial and medial-to-lateral dissection sequences, wereperformed in 14 and 4 patients of the laparoscopy group, respectively,according to whether their tumors were located above or below 20 cmabove the anal verge. After evaluating the surgical outcomes, we foundthat the laparoscopy group was significantly better than the laparotomygroup in regard to parameters that included severity of postoperativepain, wound size, postoperative complication rate, and the duration ofpostoperative ileus, hospitalization, and disability. There was nosignificant difference in the operating times for these two groups.However, the costs of the laparoscopy group were significantly higher.To evaluate the surgical stress, we measured the serum C-reactiveprotein (CRP) level, erythrocyte sedimentation rate (ESR), totallymphocyte count, and CD4+/CD8+ ratio 24 hoursbefore and after surgery. We found that the postoperative serum CRPlevel and the ESR were significantly less elevated and the totallymphocyte counts and CD4+/CD8+ ratio weresignificantly less depressed in the laparoscopy group than in thelaparotomy group. We thus concluded that laparoscopy-assistedsigmoidectomy can be safely performed with shorter convalescence andless operative stress but at a higher cost. We strongly recommended theuse of this technique in the management of sigmoid complex polyps ifthe patients economic status permits.

C2GnT-M is downregulated in colorectal cancer and its re-expression causes growth inhibition of colon cancer cells

Changes in carbohydrates on the cell surface are associated with tumor malignancy. The mucin-type core 2 β-1,6-N-acetylglucosaminyltransferase (C2GnT-M) is highly expressed in the gastrointestinal tract and catalyses the formation of core 2, core 4, and blood group I branches on O-glycans. In the present study, we evaluated the role of C2GnT-M in colorectal cancer. C2GnT-M downexpression was observed in 73.6% of the primary tumors from colorectal cancer patients (39 of 53) analysed by cancer profiling array. Consistently, the majority of colon cancer cell lines and primary colon tumors expressed lower levels of C2GnT-M than did normal colon tissues by RT–PCR. HCT116 cells stably transfected with C2GnT-M inhibited expression of the core 1 structure, Galβ1,3GalNAcα1-Ser/Thr, on the cell surface. Moreover, C2GnT-M expression suppressed cell adhesion, motility, and invasion as well as colony formation ability. The growth of C2GnT-M-transfected HCT116 and SW480 cells was dramatically suppressed, and the cell death induced by C2GnT-M was demonstrated by an increase in the annexin V-positive cells. Interestingly, C2GnT-M inhibited cell adhesion to collagen IV and fibronectin, and decreased tyrosine phosphorylation of paxillin, indicating that the changes in cancer behavior may be partly mediated by integrin-signaling pathways. Tumor growth in vivo was also significantly suppressed by C2GnT-M in the xenografts of nude mice. These results demonstrate that C2GnT-M is frequently downregulated in colorectal cancer and suppresses colon cancer cell growth.

Association Between Early Stage Colon Neoplasms and False-negative Results From the Fecal Immunochemical Test

BACKGROUND & AIMS The fecal immunochemical test (FIT) can identify patients with advanced colorectal neoplasms, but it also has a high rate of false-negative results. It would be helpful to characterize colorectal neoplasms that are not detected by FIT to aid in development of new tests. We characterized colorectal neoplasms from patients who had negative results from the FIT. METHODS We analyzed data from 18,296 subjects who were screened for colorectal cancer by colonoscopy and the FIT at the Health Management Center of National Taiwan University Hospital from September 2005 through September 2010. We identified 4045 subjects with colorectal neoplasms (3385 with nonadvanced adenomas, 632 with advanced adenomas, and 28 with cancer). We analyzed the sensitivity of the FIT in identifying these patients, along with information on lesion size, location, and morphology. RESULTS The FIT identified patients with nonadvanced adenomas, advanced adenomas, and cancer with sensitivity values of 10.6% (95% confidence interval [CI], 10.2%-12.3%), 28.0% (95% CI, 24.6%-31.7%), and 78.6% (95% CI, 58.5%-91.0%), respectively. The FIT detected proximal advanced adenomas and nonpolypoid lesions with lower levels of sensitivity than distal advanced adenomas; it had a high false-negative rate in detection of adenomas <15 mm (adjusted odds ratio, 2.85; 95% CI, 1.79-4.54) and nonpolypoid adenomas (adjusted odds ratio, 2.15; 95% CI, 1.22-3.80), after adjusting for demographic characteristics, colonoscopy findings, and potential confounders. The FIT produced a higher percentage of false-negative results in detection of carcinoma in situ and T1 cancer than in T2-T4 cancers (66.7% sensitivity vs 100%; P = .049). CONCLUSIONS The FIT produces a high rate of false-negative results for patients with small or nonpolypoid adenomas. Early-stage cancers are associated with a high rate of false-negative results from the FIT.

Comparison of medial-to-lateral versus traditional lateral-to-medial laparoscopic dissection sequences for resection of rectosigmoid cancers: randomized controlled clinical trial.

This study aimed to compare medial-to-lateral versus lateral-to-medial laparoscopic dissection sequences for resecting rectosigmoid cancers. We hypothesized that the medial-to-lateral approach was a more efficient procedure and with potentially better oncologic results. Between January 1997 and June 1999, a total of 67 patients of rectosigmoid cancer treated by one surgeon using the laparoscopic approach were recruited for this prospective, randomized, double-blind clinical trial. Using the blocked randomization method, 36 patients were allocated to a medial-to-lateral (M) group and the other 31 to a lateral-to-medial (L) group; the groups were well matched in age, gender, symptoms, body mass index, American Society of Anesthesiology (ASA) class, tumor location, tumor distance above the anal verge, tumor gross morphology, TNM stage of the tumor, and accuracy of preoperative TNM staging (p > 0.05). All patients were followed up until June 2001. We found that the M group had a significantly shorter operating time and lower overall costs than the L group (p < 0.05). There was no significant difference between these two groups in terms of intraoperative complications, conversion rate, postoperative ileus, hospitalization, postoperative pain, postoperative complications, wound length, or disability (p > 0.05). The postoperative proinflammatory response, evaluated by the C-reactive protein level and the erythrocyte sedimentation rate, was significantly lower in the M group (p < 0.05). There was no significant difference between these two groups regarding postoperative immunosuppression, as evaluated by the alterations of total lymphocyte counts and the CD4+/CD8+ ratio (p > 0.05). The extent of dissection of these two dissection approaches was similar, as the harvested lymph nodes were equivalent (p > 0.05). During the whole follow-up period (median 32 months, range 24–54 months), the tumor recurrence rate was similar for these two groups of patients (5.6% in the M group vs. 6.5% in the L group; p > 0.05). These findings indicated that the medial-to-lateral approach was quicker, less expensive and possibly less invasive; moreover, it gave oncologic results similar to those achieved with the traditional lateral-to-medial dissection sequence. We thus concluded that the medial-to-lateral dissection sequence may currently be the most appropriate procedure for laparoscopic resection of rectosigmoid cancers.

P53 overexpression predicts poor chemosensitivity to high-dose 5-fluorouracil plus leucovorin chemotherapy for stage IV colorectal cancers after palliative bowel resection

Our study aims to further clarify the prognostic significance of p53 overexpression in stage IV colorectal cancer. Between January 1994 and June 1997, we recruited 144 patients with stage IV colorectal cancers for our study, based on appropriate eligibility criteria. The patients were nonrandomly allocated to 2 treatment groups of either with or without high‐dose 5‐fluorouracil plus leucovorin chemotherapy (HDFL: 5‐Fu: 2,600 mg/m2 leucovorin 300 mg/m maximum 500 mg). Each treatment group was further divided into 2 subgroups according to the status of p53 overexpression. Therefore, 4 subgroups were allocated in our study and were designated as p53 (overexpression) HDFL (+), n = 65; p53 (normal) HDFL (+), n = 37; p53 (overexpression) HDFL (−), n = 27; and p53 (normal) HDFL (−), n = 15, respectively. All patients were prospectively followed until April 2001. There was no significant difference of the background clinicopathologic data of these 4 allocated subgroups of patients (p > 0.05). Multivariate analysis of various clinicopathologic factors of the whole group of patients indicated that age ≥60 years, poor differentiation, mucin production, CEA >100 ng/ml, p53 overexpression and without chemotherapy were the significant independent poor prognostic factors (p < 0.05). Survival analyses indicated that the patients of subgroup p53 (normal) HDFL (+) survived significantly longer than those of subgroup p53 (overexpression) HDFL (+), with mean survival time (95% confidence interval [CI]) of 20.24 (16.24–24.25) and 13.29 (10.98–15.60) months, respectively (p = 0.0043, log‐rank test). In contrast, in patients without chemotherapy, the prognosis was poor regardless of their p53 status, with mean survival time (95% CI) of 6.85 (5.47–8.23) and 5.87 (4.48–7.26) months in p53 (overexpression) HDFL (−) and p53 (normal) HDFL (−) subgroups of patients, respectively (p = 0.2820, log‐rank test). Cancers of normal p53 expression responded significantly better to HDFL (p < 0.05), with mean response rate (95% CI) being 65.57% (52.18–82.96%) in subgroup p53 (normal) HDFL (+) as compared to 35.38% (23.52–47.24%) in subgroup p53 (overexpression) HDFL (+). The toxicity to HDFL was similarly minimal between p53‐normal and p53‐overexpression patients (p > 0.05). We thus concluded that the poorer prognosis of stage IV colorectal cancers with p53 overexpression was associated with their poorer chemosensitivity rather than the more biologic aggressiveness.

Microvessel density, cyclo‐oxygenase 2 expression, K‐ras mutation and p53 overexpression in colonic cancer

Tumour angiogenesis, cyclo‐oxygenase (COX) 2 expression, K‐ras mutation and p53 overexpression are commonly involved in colorectal tumorigenesis, but their interrelationship and clinicopathological effects remain inconclusive.