Establishment and characterization of an opisthorchiasis-associated cholangiocarcinoma cell line (KKU-100)

AIM To establish and dharacterize a nev cholangiocarcinoma cell line from a patient living in the Opisthorchis viverrini (O. viverrini) endemic area of Northeast Thailand.METHODS: Fresh liver biopsy and bile specimens were obtained from a 65-year-old Thai woman with cholangiocarcinoma of the porta hepatis. After digestion, the cells were cultured in Ham's F12 media. The established cell line was then characterized for growth kinetics, cell morphology, imm unocytochemistry and cytogenetics. Tumorigenicity of the cell line was determined by heterotransplanting in nude mice. RESULTS: The primary tumor was a poorly differentiated tubular adenocarcinoma. Examination of the bile revealed malignant cells with O. viverrini eggs. The cholangiocarcinoma cell line KKU-100 was established 4 mo after the primary culture-population doubling time was 72 h. KKU-100 possesses compact and polygonal-shapedepithelial cells. Immunocytochemically, this cell line exhibited cytokeratin, EMA, CEA, and CA125, but not α-fetoprotein (AFP), CA19-9, desmin, c-met, or p53. Such protein expressions parallel those of the primary tumor. Cytogenetic analysis identified aneuploidy karyotypes with a modal chromosome number of 78 and marked chromosomal structural changes. Inoculation of KKU-100 cells into nude mice produced a transplantable, poorly differentiated aden-ocarcinoma, similar to the original tumor.CONCLUSION: KKJ-100 is the first egg-proven, Opisthorchis- associated cholangiocarcinoma cell line, which should prove useful for further investigations of the tumor biology of this cancer.

Genetic and environmental determinants of risk for cholangiocarcinoma in Thailand

Cholangiocarcinoma(CCA) is a difficult cancer to diagnose in the early stage and to treat by curative resec-tion. The incidence of CCA in the northeast of Thailand is the highest in the world. To make progress in detecting a high risk group and in the prevention and detection of CCA, we have been analyzing the risk factors for CCA. Although liver fluke infection is known to be a risk factor, there are patients who are not infected with the liver fluke and not all people infected with the liver fluke will suffer from the disease. Therefore, it is of the utmost importance to analyze the risk factors and the mechanism to prevent the disease and also to detect the disease in its early stage to save patients' lives. Through collaboration among Thai and Japanese researchers, we analyzed the genetic and environmental determinants of risks for CCA. Also, we have been trying to develop methods to detect the disease in a non-invasive way. Without repeating findings reported in various reviews on CCA, we will first discuss the environmental and genetic determinants of the risks for CCA. Second, we will discuss the properties of CCA, including the etiological agents and the mechanism of cholangiocarcinogenesis, and finally, we will discuss future approaches to prevent and cure CCA from the standpoint of evidence-based medicine. We will discuss these points by including the data from our laboratories. We would like to emphasize the importance of the genetic data, especially whole genome approaches, to understand the properties of CCA, to find a high risk population for CCA and to develop effective preventative methods to stop the carcinogenic steps toward CCA in the near future. In addition, it is of the upmost importance to develop a non-invasive, specific and sensitive method to detect CCA in its early stage for the application of modern medical approaches to help patients with CCA.

Biofilm formation in trimethoprim/sulfamethoxazole-susceptible and trimethoprim/sulfamethoxazoleresistant uropathogenic Escherichia coli

Objective: To compare bioi lm formation in trimethoprim/sulfamethoxazole(SXT)-susceptible Escherichia coli(E. coli)(SSEC) and SXT-resistant E. coli(SREC) isolated from patients with urinary tract infections, and study the motile ability and physical characteristics of the isolates.Methods: A total of 74 E. coli isolates were tested for antimicrobial susceptibility with the disc diffusion assay. Based on the SXT-susceptibility test, the E. coli isolates were divided into SSEC(N = 30) and SREC(N = 44) groups. All E. coli isolates were examined for motile ability by using a motility test medium, and for checking bioi lm formation a scanning electron microscope was used. Bacterial colony size was measured with a vernier caliper and bacterial cell length was measured under a light microscope. The bacterial growth rate was studied by plotting the cell growth(absorbance) versus the incubation time. Results: The frequencies of non-motility and biofilm formation in the SREC group were signii cantly higher than that in the SSEC group(P < 0.01). The SREC bacterial cell length was shorter than that in the SSEC group [(1.35 ± 0.05) vs.(1.53 ± 0.05) μm, P < 0.05)], whereas the bacterial colony size and mid-log phase of the growth curve were not signii cantly dif erent. Conclusions: The present study indicated that bioi lm formation and phenotypic change of uropathogenic E. coli can be attributed to the mechanism of E. coli SXT resistance.