Abstract Background: The importance of gene inactivation by promoter CpG island hypermethylation has encouraged the unearthing of silenced tumor suppressor genes (TSGs) in various cancers. We aimed to identify and examine novel methylation silenced TSGs in colorectal cancer (CRC). Method: We employed Oligonucleotide microarray to find changes in global gene expression of five colon cancer cell lines (HCT116, RKO, Colo320, SW480, and HT29) that were analyzed before and after treatment with the demethylating agent 5-aza-2′-Deoxycitidine (5-aza-dC), expression of the responding genes was compared with microarray expression data of CRC tissue samples. Five genes (ASPP1, GADD45B, LIFR, SCARA5, and THSD1), which had a putative 5′ CpG islands in their promoter, were subjected to methylation-specific PCR (MSP) using 13 colon cell lines and 23 paired tumor and normal CRC tissues. Result: Seventy-two genes were up-regulated in demethylated cell lines and were simultaneously down-regulated in primary colorectal carcinomas, including genes that were known to be frequently hypermethylated and silenced in CRC. Among 13 colon cancer cell lines, hypermethylation was identified for three of five candidate genes, LIFR (61%), SCARA5 (15%), and THSD1 (23%). The methylation status of LIFR, SCARA5, and THSD1 was subsequently investigated in 23 colorectal tumors, hypermethylation was detected in (87%), (17%), and (9%), respectively. Data from normal colorectal mucosa demonstrated that the observed promoter hypermethylation was cancer-specific in the latter two genes. Conclusion: The use of a refined microarray screening led to the identification of two TSGs affected by hypermethylation with a cancer-specific manner in CRC. SCARA5 and THSD1 may have a role in CRC tumorigenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C18.
We report a case of sigmoid colon cancer, successfully treated by a multidisciplinary strategy for local recurrence and distant metastases. This 60-year-old male patient underwent sigmoidectomy for sigmoid colon cancer. Three years after the operation, local recurrence with invasion to the left ureter was found, and we performed colectomy and left nephroureterectomy. One year after the resection, a second relapse lesion was discovered, which was considered unresectable, and was treated instead with radiation therapy(total 50 Gy). One year after the radiation therapy, five pulmonary metastases each of 12 mm in diameter were found in both lungs. He had renal dysfunction due to nephrectomy. Several regimens of chemotherapy [irinotecan (CPT-11), capecitabine+oxaliplatin (CapeOx) and CPT-11+panitumumab] were performed. He is still alive 7.5 years after the initial surgery and 4.5 years after the first recurrence.
We present two cases of multiple liver metastases from colorectal cancer, which did not respond to hepatic arterial infusion (HAI) using 5-fluorouracil (5-FU 1250 mg/body weekly) alone, but responded to HAI using 5-fluorouracil (5-FU 750 mg/body weekly) and l-leucovorin (l-LV 50 mg/body weekly) achieving a complete response (CR). The first case: A 71-year-old man with Stage II rectal cancer who underwent lower anterior resection developed multiple liver metastases 5 months after the surgery. As the weekly HAl using 5-FU for nine courses showed no response, l-LV was combined, and the liver metastases disappeared after 10 courses to achieve CR. The second case: A 65-year-old man with rectal cancer, sigmoid colon cancer and multiple liver metastases underwent lower anterior resection. The weekly HAl using 5-FU for seven courses showed no response. By combining 5-FU to l-LV, the liver metastases disappeared after fifteen courses. No toxic event was observed. In these two cases, it was suspected that a reduced foliate may be responsible for the failure by the 5-FU treatment alone.
Colorectal cancer (CRC) is one of the most frequently occurring cancers in Japan, and thus a wide range of methods have been deployed to study the molecular mechanisms of CRC. In this study, we performed a comprehensive analysis of CRC, incorporating copy number aberration (CRC) and gene expression data. For the last four years, we have been collecting data from CRC cases and organizing the information as an "omics" study by integrating many kinds of analysis into a single comprehensive investigation. In our previous studies, we had experienced difficulty in finding genes related to CRC, as we observed higher noise levels in the expression data than in the data for other cancers. Because chromosomal aberrations are often observed in CRC, here, we have performed a combination of CNA analysis and expression analysis in order to identify some new genes responsible for CRC. This study was performed as part of the Clinical Omics Database Project at Tokyo Medical and Dental University. The purpose of this study was to investigate the mechanism of genetic instability in CRC by this combination of expression analysis and CNA, and to establish a new method for the diagnosis and treatment of CRC.Comprehensive gene expression analysis was performed on 79 CRC cases using an Affymetrix Gene Chip, and comprehensive CNA analysis was performed using an Affymetrix DNA Sty array. To avoid the contamination of cancer tissue with normal cells, laser micro-dissection was performed before DNA/RNA extraction. Data analysis was performed using original software written in the R language.We observed a high percentage of CNA in colorectal cancer, including copy number gains at 7, 8q, 13 and 20q, and copy number losses at 8p, 17p and 18. Gene expression analysis provided many candidates for CRC-related genes, but their association with CRC did not reach the level of statistical significance. The combination of CNA and gene expression analysis, together with the clinical information, suggested UGT2B28, LOC440995, CXCL6, SULT1B1, RALBP1, TYMS, RAB12, RNMT, ARHGDIB, S1000A2, ABHD2, OIT3 and ABHD12 as genes that are possibly associated with CRC. Some of these genes have already been reported as being related to CRC. TYMS has been reported as being associated with resistance to the anti-cancer drug 5-fluorouracil, and we observed a copy number increase for this gene. RALBP1, ARHGDIB and S100A2 have been reported as oncogenes, and we observed copy number increases in each. ARHGDIB has been reported as a metastasis-related gene, and our data also showed copy number increases of this gene in cases with metastasis.The combination of CNA analysis and gene expression analysis was a more effective method for finding genes associated with the clinicopathological classification of CRC than either analysis alone. Using this combination of methods, we were able to detect genes that have already been associated with CRC. We also identified additional candidate genes that may be new markers or targets for this form of cancer.
We first demonstrate a field-effect-transistor operation of dimetallofullerene La2@C80 with the icosahedral cage symmetry. The thin-film device showed an n-type behavior with a mobility of 1.1 x 10-4 cm2/V s at room temperature under high vacuum. Taking the nature of LUMO into account, the n-type behavior indicates an occurrence of carrier conduction through encapsulated La ions. The low mobility, suggesting an intermolecular hopping mechanism, is ascribed to the intrinsic and extrinsic reasons, which are discussed in the text.
<i>Purpose:</i> We investigated whether a 5-fluorouracil (5-FU)-resistant tumor could regain chemosensitivity after the administration of 5-aza-2′-deoxycytidine (DAC) as a demethylating agent. <i>Methods:</i> Human colorectal cancer cells (SW48) are characterized by the hypermethylation of proapoptotic genes. They were transplanted into 20 athymic BALB/c nu/nu mice which were randomly placed into 4 groups (1 = control; 2 = 5-FU alone; 3 = DAC alone; 4 = DAC followed by 5-FU). We evaluated the synergistic effect of DAC and 5-FU on the growth of these xenografts. Reactivation of proapoptotic genes in these cells was analyzed by methylation-specific PCR. Gene expression was determined by a quantitative reverse-transcription PCR assay. <i>Results:</i> Compared with the control group, relative tumor volumes were statistically significantly decreased only in group 4 mice (p = 0.006). In groups 3 and 4, p14, p16 and death-associated protein kinase (DAPK) promoter regions were demethylated and p14 gene expression was gradually increased after DAC administration. <i>Conclusion:</i> DAC could be a useful medicine that breaks the silencing of various genes and recovers some expressions. By pretreating with DAC at a nontoxic level, we confirmed the restoration of 5-FU chemosensitivity and apoptosis induction. The combination of demethylating agents and several cytotoxic drugs has potential in clinical practice.
Identification of methylation-silenced genes in colorectal cancer (CRC) is of great importance. We employed oligonucleotide microarrays to identify differences in global gene expression of five CRC cell lines (HCT116, RKO, Colo320, SW480 and HT29) that were analyzed before and after treatment with 5-aza-2'-deoxycitidine. Selected candidates were subjected to methylation-specific PCR and real-time quantitative reverse transcription-PCR using 15 CRC cell lines and 23 paired tumor and normal samples from CRC patients. After 5-aza-2'-deoxycitidine treatment, 139 genes were re-expressed in all 5 CRC cell lines collectively with a fold change of more than 1.5 in at least one cell line. These genes include known methylated and silenced genes in CRC. After applying study selection criteria we identified 20 candidates. The GADD45B and THSD1 genes were selected for further analysis. Among 15 colon cancer cell lines, methylation was only identified in THSD1 (27%). THSD1 methylation was subsequently investigated in 23 colorectal tumors and methylation was detected in 9% of the analyzed samples; the observed promoter hypermethylation was cancer-specific. THSD1 mRNA down-regulation was observed in tumor tissues. This genome-wide screening led to the identification of genes putatively affected by methylation in CRC. The THSD1 gene may play a role in the tumorigenesis of CRC.
