High-resolution genomic profiles of breast cancer cell lines assessed by tiling BAC array comparative genomic hybridization

A BAC-array platform for comparative genomic hybridization was constructed from a library of 32,433 clones providing complete genome coverage, and evaluated by screening for DNA copy number changes in 10 breast cancer cell lines (BT474, MCF7, HCC1937, SK-BR-3, L56Br-C1, ZR-75-1, JIMT1, MDA-MB-231, MDA-MB-361, and HCC2218) and one cell line derived from fibrocystic disease of the breast (MCF10A). These were also characterized by gene expression analysis and found to represent all five recently described breast cancer subtypes using the "intrinsic gene set" and centroid correlation. Three cell lines, HCC1937 and L56BrC1 derived from BRCA1 mutation carriers and MDA-MB-231, were of basal-like subtype and characterized by a high frequency of low-level gains and losses of typical pattern, including limited deletions on 5q. Four estrogen receptor positive cell lines were of luminal A subtype and characterized by a different pattern of aberrations and high-level amplifications, including ERBB2 and other 17q amplicons in BT474 and MDA-MB-361. SK-BR-3 cells, characterized by a complex genome including ERBB2 amplification, massive high-level amplifications on 8q and a homozygous deletion of CDH1 at 16q22, had an expression signature closest to luminal B subtype. The effects of gene amplifications were verified by gene expression analysis to distinguish targeted genes from silent amplicon passengers. JIMT1, derived from an ERBB2 amplified trastuzumab resistant tumor, was of the ERBB2 subtype. Homozygous deletions included other known targets such as PTEN (HCC1937) and CDKN2A (MDA-MB-231, MCF10A), but also new candidate suppressor genes such as FUSSEL18 (HCC1937) and WDR11 (L56Br-C1) as well as regions without known genes. The tiling BAC-arrays constitute a powerful tool for high-resolution genomic profiling suitable for cancer research and clinical diagnostics.     

A Class of Tricyclic Compounds Blocking Malaria Parasite Oocyst Development and Transmission

Malaria is a deadly infectious disease in many tropical and subtropical countries. Previous efforts to eradicate malaria have failed, largely due to the emergence of drug-resistant parasites, insecticide-resistant mosquitoes and, in particular, the lack of drugs or vaccines to block parasite transmission. ATP-binding cassette (ABC) transporters are known to play a role in drug transport, metabolism, and resistance in many organisms, including malaria parasites. To investigate whether a Plasmodium falciparum ABC transporter (Pf14_0244 or PfABCG2) modulates parasite susceptibility to chemical compounds or plays a role in drug resistance, we disrupted the gene encoding PfABCG2, screened the recombinant and the wild-type 3D7 parasites against a library containing 2,816 drugs approved for human or animal use, and identified an antihistamine (ketotifen) that became less active against the PfABCG2-disrupted parasite in culture. In addition to some activity against asexual stages and gametocytes, ketotifen was highly potent in blocking oocyst development of P. falciparum and the rodent parasite Plasmodium yoelii in mosquitoes. Tests of structurally related tricyclic compounds identified additional compounds with similar activities in inhibiting transmission. Additionally, ketotifen appeared to have some activity against relapse of Plasmodium cynomolgi infection in rhesus monkeys. Further clinical evaluation of ketotifen and related compounds, including synthetic new derivatives, in blocking malaria transmission may provide new weapons for the current effort of malaria eradication.     

A case of rectal implantation cyst diagnosed by EUS and EUS-guided FNA

A 73-year-old woman was referred to our hospital complaining of bloody stool. She had undergone high anterior resection with the double stapling technique for a sigmoid colon cancer 2 years prior to this admission. Colonoscopy revealed a soft submucosal tumor, 4cm in size, on the anal side of the previous anastomosis in the rectum. EUS revealed a cystic lesion located in the third and fourth layers of the rectal wall. EUS-FNA was performed, and the content of the cystic lesion was transparent mucinous liquid. Histologically, the specimen revealed PAS and Alcian blue-positive mucinous material and a small number of inflammatory cells such as foamy macrophages. Therefore, this cystic lesion was diagnosed as a rectal implantation cyst.     

Evaluation of ERCC1 Expression for Cisplatin Sensitivity in Human Hepatocellular Carcinoma

Background

Excision repair cross-complementation group 1 (ERCC1) is one of the key enzymes in DNA repair. This study was designed to investigate the correlation between ERCC1 expression and chemosensitivity to cisplatin (CDDP) in patients with hepatocellular carcinoma (HCC).

Methods

Eighty-seven HCC samples were analyzed by immunohistochemistry for ERCC1 and chemosensitivity was assessed by the succinate dehydrogenase inhibition (SDI) test for four anti-cancer agents, including CDDP. The ERCC1 expression was examined in HCC cell lines. ERCC1 siRNA was transfected to PLC/RPF/5 to investigate the correlation of ERCC1 expression and CDDP sensitivity.

Results

ERCC1 expression was observed in 33% of nuclei in immunohistochemical examination. Patients were divided into two groups as follows: ERCC1 high expression group (n = 43): more than 33% of the nuclei were stained; ERCC1 low expression group (n = 44): 33% or fewer of the nuclei were stained. Tumor size of low expression group was larger than that in the high expression group (p = 0.02). The succinic dehydrogenase (SD) activity only for CDDP was significantly higher in the high expression group than that in the low expression group (p = 0.02). An increased expression of ERCC1 was shown by immunohistochemical and Western blot analyses in PLC/RPF/5. ERCC1 expression was inhibited by ERCC1 siRNA transfection and the LC50 value (nM) of CDDP was reduced from 25.7 to 12.5 (p = 0.01).

Conclusions

Increased ERCC1 expression is associated with CDDP resistance in HCC specimens and cell lines. Therefore, immunohistochemical analysis for resected HCC tissues may be a useful predictor for the effectiveness of adjuvant chemotherapy, using CDDP.     

The biological role of the glycinergic synapse in early zebrafish motility

Glycine mediates fast inhibitory neurotransmission in the spinal cord, brainstem and retina. Loss of synaptic glycinergic transmission in vertebrates leads to a severe locomotion defect characterized by an exaggerated startle response accompanied by transient muscle rigidity in response to sudden acoustic or tactile stimuli. Several molecular components of the glycinergic synapse have been characterized as an outcome of genetic and physiological analyses of synaptogenesis in mammals. Recently, the glycinergic synapse has been studied using a forward genetic approach in zebrafish. This review aims to discuss molecular components of the glycinergic synapse, such as glycine receptor subunits, gephyrin, gephyrin-binding proteins and glycine transporters, as well as recent studies relevant to the genetic analysis of the glycinergic synapse in zebrafish.     

Immunological responses against Plasmodium falciparum Apical Membrane Antigen 1 vaccines vary depending on the population immunized

Clinical development of malaria vaccines progresses from trials in malaria naïve adults to malaria exposed adults followed by malaria exposed children. It is not well known whether immune responses in non-target populations are predictive of those in target populations, particularly in African children. Therefore humoral responses in three different populations (U.S. adults, Malian adults and Malian children) were compared in this study. They were immunized with 80 μg of Apical Membrane Antigen 1 (AMA1)/alhydrogel on days 0 and 28. Sera were collected on days 0 and 42; antibody levels were determined by ELISA and the functionality of antibodies was evaluated by Growth Inhibition Assay. After immunization, there was no significant difference in antibody levels between the Malian children and the Malian adults, but U.S. adults showed lower antibody levels. Vaccination did not significantly change growth-inhibitory activity in Malian adults, but inhibition increased significantly in both U.S. adults and Malian children. Vaccine-induced inhibitory activity was reversed by pre-incubation with AMA1 protein, but pre-existing infection-induced inhibition was not. This study shows that humoral responses elicited by the AMA1 vaccine varied depending on the population, most likely reflecting different levels of previous malaria exposure. Thus predicting immune responses from non-target populations is not desirable.