We demonstrated novel sequence structures and a functional role of CES1A genes in CPT-11 responses. We believe that our novel findings will be of key importance in developing a really useful prediction method for CPT-11 chemosensitivity.

Purpose: Dihydropyrimidine dehydrogenase (DPD), the initial rate-limiting enzyme in the degradation of 5-fluorouracil (5-FU), is known to be a principal factor in clinical responses to the anticancer agent 5-FU, and various reports have clearly demonstrated that DPD activity is closely correlated to mRNA levels. However, the regulatory mechanisms of DPD gene (DPYD) expression remain unclear. In this study, the regulatory mechanisms have been intensively studied.Experimental Design and Results: A subcloned 3.0-kb fragment of the 5 region of DPYD contains a total of 60 CpG sites, suggesting that methylation status may affect the repression of DPYD. The clone showed various promoter activities that were largely correlated with mRNA levels in most cell lines, except HSC3 and HepG2. Bisulfite sequencing analysis revealed that various CpG sites around the transcription start site were abnormally methylated in cells with low DPYD expression: Reversal of hypermethylation by 5-azacytidine treatment significantly increased DPYD expression in HSC3 and HepG2 cells that showed strong promoter activity. In HepG2, in vitro methylation of the DPYD promoter directly decreased promoter activity, and 5-azacytidine treatment restored higher DPYD expression in a dose-and time-dependent manner, along with decreased sensitivity to 5-FU.Conclusions: We found that DPD activity was controlled, at least in part, at the transcription level of DPYD and that aberrant methylation of the DPYD promoter region acted as one of the repressors of DPYD expression and affected sensitivity to 5-FU in cancer cells. Our new results could lead to a more precise understanding of the molecular basis of 5-FU response.

Abstract. Prior laboratory prediction of individual drug response is of key importance in esophageal squamous cell carcinoma (ESCC), because of the extremely narrow therapeutic index of chemotherapy. However, very few critical markers have been validated to date for ESCC. We previously demonstrated that simultaneous performance of two different types of comprehensive gene expression analysis might provide a way to identify potent marker genes for drug sensitivity from the expression-sensitivity correlation analysis alone, but the screening method appeared not to be always effective. Therefore, we attempted to identify novel potent marker genes using a new statistical analysis of oligonucleotide microarray expression data, based on a two-dimensional mixed normal model, and selected 3 and 7 novel candidates for 5-fluorouracil (5-FU) and cis-platinum (CDDP), respectively. Interferon induced transmembrane protein 1 (IFITM1) gene alone, being suggested as a key gene of Wnt pathway, was commonly selected in both screening methods. The transfection analyses and siRNA-mediated knock-down experiments revealed that expression of IFITM1 closely related to cellular sensitivity to CDDP. Considering the fact that drug sensitivity is determined by multiple genes, we established the best linear model using quantified expression data of a set of all the selected marker genes including IFITM1, which converted the quantified expression data of ESCC cell lines into an IC 50 value of each drug. In the same way, using the representative genes selected in vitro, we developed highly predictive formulae for disease-free survival (DFS) of the CDDP/5-FU combination after curative operation in esophageal cancer patients (R=0.917). A two-dimensional mixed normal model can be a powerful tool to identify novel drug-response determinants, and the IFITM1 gene selected by the statistical method a novel critical biomarker of CDDP response in ESCC.

Abstract. Esophageal cancer is a highly lethal disease and the optimal therapy remains unclear. Since adjuvant chemotherapy gives a better chance of survival, we attempted to develop a chemosensitivity prediction model to improve individual responses to therapy. Comprehensive gene expression analyses (cDNA and oligonucleotide microarrays) and MTT assay of 8 drugs in 20 KYSE squamous cell carcinoma cell lines were performed to distinguish candidate marker genes whose expression levels reproducibly correlated with cellular drug sensitivities. After confirmation with real-time RT-PCR, we performed multiple regression analyses to develop drugsensitivity prediction formulae using the quantified expression data of selected marker genes. Using the same sets of genes, we also constructed prediction models for individual clinical responses to 5-FU-based chemotherapy using 18 cases. We selected 5 better marker genes, known as drug sensitivity determinants, identified 9 novel predictive genes for 4 of 8 anticancer drugs [5-FU, CDDP, DOX, and CPT-11 (SN-38)], and developed highly predictive formulae of in vitro sensitivities to the 4 drugs and clinical responses to 5-FU-based adjuvant chemotherapies in terms of overall and disease-free survivals. Our selected genes are likely to be effective drug-sensitivity markers and formulae using the 9 novel genes would provide advantages in prediction.

BackgroundThe incidence of axillary lymph node metastasis (ALNM) of colon cancer is very low, and there have been only a few reports of solitary ALNM. Neither the mechanism involved in solitary colon cancer ALNM nor the proper treatment has been elucidated. We encountered a case of solitary left ALNM after curative resection of carcinoma at the colostomy site.Case presentationA 53-year-old man underwent a Hartmann’s operation for Hirschsprung disease during his adolescence. He complained of a mass of the descending colon and was diagnosed with colon cancer at the colostomy site with pagetoid spread to the adjacent skin. The cancer at the stoma site was resected, and a transverse colostomy was performed. Nine years later, his carbohydrate antigen (CA) 19-9 level was high during a health screening. On physical examination, adenopathy was palpated in the left axilla. Computed tomography (CT) demonstrated a lymph node in the left axillary fossa that was 33 mm in diameter, and 18F-fluorodeoxyglucose positron emission tomography/CT showed high uptake in the lesion. We performed a curative resection of the left axillary lymph node. The lesion was pathologically diagnosed as left ALNM originating from the adenocarcinoma at the colostomy site. After lymph node resection, his serum CA19-9 level decreased compared to that observed at baseline. He has been receiving adjuvant chemotherapy (capecitabine plus oxaliplatin) without recurrence for 5 months after lymph node resection.ConclusionsThe present case report shows that carcinoma at the colostomy site with pagetoid spread can metastasize to the axillary lymph nodes through superficial abdominal lymphatic pathways, and surgical resection followed by adjuvant chemotherapy may be a potent strategy to treat solitary colon cancer ALNM.