[A cross-sectional study of periodontal pathogens in saliva of edentulous patients]

Objective: To investigate the prevalence of five specific periodontal pathogens in the saliva of edentulous patients and to compare the differences in the saliva of dentulous individuals with various periodontal conditions. Methods: All the subjects were patients who received regular care at the Beijing Hypertension Prevention and Management Institute. Twenty-seven edentulous patients (edentulous group) were included. According to age (age gap≤5 years), gender, smoking status, diabetes status and hypertension status, each edentulous patient was paired with dentulous individuals suffering from various severity of periodontitis in the same cohort. Then, we selected 3 groups of patients (n=27 in each group) with no or mild periodontitis (mild group), moderate periodontitis (moderate group) and severe periodontitis (severe group). The whole unstimulated saliva was collected before the periodontal examination. Questionnaire survey and periodontal parameters, including plaque index (PLI), probing depth (PD), bleeding index (BI) and clinical attachment loss (CAL), were examined at mesial-buccal and distal-lingual sites of each tooth respectively. DNA was extracted from each sample of the salivary deposition. Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), Campylobacter rectus (Cr) and Prevotella nigrescens (Pn) were detected by using PCR method based on 16SrRNA. The prevalence and quantity of the pathogens under various severity of periodontitis were compared. Results: One or more periodontal pathogens could be detected from the 78% (21/27) of the salivary samples in edentulous group. Thereinto, the prevalences of the five periodontal pathogens were ranked as (from high to low): Cr [56% (15/27)], Tf [44% (12/27)], Pn [26% (7/27)], Pg [22% (6/27)] and Td [11% (3/27)]. All five pathogens' prevalences and Pg, Tf, Td and Pn's quantities showed statistical differences among the four groups. The numbers of detected bacterial species in the mild, moderate and severe groups were significantly higher than that in the edentulous group (P<0.01). Furthermore, the prevalences of the red complex in three dentulous groups [96% (26/27) in each group] were significantly higher than the edentulous group [48% (13/27)] (P<0.05). The proportions of the red complex among all five pathogens (83%) in moderate and severe groups were significantly higher than that in the edentulous group (37%) (P<0.01). Conclusions: All five periodontal pathogens could be detected in most of the saliva samples from edentulous individuals. Nevertheless, the prevalence and quantity were lower than dentulous individuals.

[Expression of hepatocyte nuclear factor 4γ in gastric carcinoma and its role in cell proliferation and stemness]

Objective: To explore the role and molecular mechanism of hepatocyte nuclear factor 4γ (HNF4γ) in proliferation and stemness of gastric cancer. Methods: A total of 102 cases of paraffin-embedded gastric cancer tissues and matched adjacent gastric tissues and 42 cases of fresh-frozen tissues derived from gastric patients who received radical gastrectomy were collected from the First Affiliated Hospital of Zhengzhou University between 2012 to 2015. The expression of HNF4γ was tested by immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR). HNF4γ overexpressed (AGS-HNF4γ) and shRNA silenced (HGC27-shHNF4γ) gastric cell lines were established. The effects of HNF4γ on cell proliferation and stemness were verified by XTT, clone formation and sphere formation assay. The expression of CD44 was detected by western blot. Results: The mRNA expression level of HNF4γ in fresh-frozen gastric cancer tissue was (12.43±2.702), which was significantly higher than (3.639±1.109) in normal tissue (P<0.001). The high protein expression rate of HNF4γ in paraffin-embedded gastric cancer tissues was 41.2% (42/102), which was significantly higher than 8.8% (9/102) in normal gastric mucosa tissue (P< 0.001). The protein expression of HNF4γ was closely related to the tumor differentiation, infiltration depth, lymph node metastasis and tumor stage (P<0.05). The median survival interval of patients with HNF4γ high expression was 25 months, the 3-year survival rate was 4.8% (2/42), significantly lower than 38 months and 51.7% (31/60) of patients with normal HNF4γ expression (P<0.001). The proliferation and CD44 protein expression of AGS-HNF4γ cells were significantly higher than those of the AGS-Vector cells. The number of clone formation, sphere formation rate of AGS-HNF4γ cells were 243.5±24.5 and (83.5±3.9)%, significantly higher than 81.0±16.0 and (21.8±5.6)% of AGS-Vector cells (P=0.030 and P=0.010, respectively). The proliferation and CD44 protein expression of HGC27-shHNF4 cells were significantly lower than those of the HGC27-vector cells. The number of clone formation, sphere formation rate of HGC27-shHNF4 cells were 26.0±1.0 and (20.8±8.4)%, significantly higher than 83.5±4.5 and (72.5±4.8)% of HGC27-vector cells (P=0.006 and P=0.030, respectively). Conclusions: HNF4γ is upregulated in the gastric cancer tissues and related with the poor prognosis of patients with gastric cancer. Overexpression of HNF4γ promotes the proliferation and remains the stemness of gastric cancer cells by upregulating the expression of CD44.

Prognostic and therapeutic evaluation of nasopharyngeal carcinoma by dynamic contrast-enhanced (DCE), diffusion-weighted (DW) magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS)

Nasopharyngeal carcinoma (NPC) is an aggressive head and neck malignancy, and radiotherapy (with or without chemotherapy) is the primary treatment modality. Reliable tumour assessment during the treatment phase, which can portend the efficacy of radiotherapy and early identification of potential treatment failure in radioresistant disease, has been implicit for better cancer management. Technological advancement in the last decade has fostered the development of functional magnetic resonance imaging (fMRI) techniques into a promising tool for diagnostic and therapeutic assessments in head and neck cancer. Apart from conventional morphological assessment, early detection of the physiological environment by fMRI allows a more thorough investigation in monitoring tumour response. This article discusses the relevant fMRI utilities in NPC as an early prognostic and monitoring tool for treatment. Challenges and future developments of fMRI in radiation oncology are also discussed.

Corrigendum: Physical Organohydrogels With Extreme Strength and Temperature Tolerance

[This corrects the article DOI: 10.3389/fchem.2020.00102.].

Physical Organohydrogels With Extreme Strength and Temperature Tolerance

Tough gel with extreme temperature tolerance is a class of soft materials having potential applications in the specific fields that require excellent integrated properties under subzero temperature. Herein, physically crosslinked Europium (Eu)-alginate/polyvinyl alcohol (PVA) organohydrogels that do not freeze at far below 0°C, while retention of high stress and stretchability is demonstrated. These organohydrogels are synthesized through displacement of water swollen in polymer networks of hydrogel to cryoprotectants (e.g., ethylene glycol, glycerol, and d-sorbitol). The organohydrogels swollen water-cryoprotectant binary systems can be recovered to their original shapes when be bent, folded and even twisted after being cooled down to a temperature as low as -20 and -45°C, due to lower vapor pressure and ice-inhibition of cryoprotectants. The physical organohydrogels exhibit the maximum stress (5.62 ± 0.41 MPa) and strain (7.63 ± 0.02), which is about 10 and 2 times of their original hydrogel, due to the synergistic effect of multiple hydrogen bonds, coordination bonds and dense polymer networks. Based on these features, such physically crosslinked organohydrogels with extreme toughness and wide temperature tolerance is a promising soft material expanding the applications of gels in more specific and harsh conditions.

Identification of chemokine CXCL10 in tumor microenvironment by antibody array as a prognostic marker in hepatocellular carcinoma

Immunological microenvironment is not only composed of multiple immune cells, but also deposited various inflammation factors that regulate immune response to tumor cells. To ascertain the crucial immune factors presented in hepatocellular carcinoma microenvironment (HCM), tumor tissue culture supernatant (TCS) and the corresponding non-tumor tissue culture supernatant (NCS) from patient with hepatocellular carcinoma (HCC) were analyzed by antibody array technology. Among the inflammation-associated cytokines assayed, high level of chemokines CXCL8/IL-8 (6.82-fold increase) and CXCL10/IP-10 (16.45-fold increase) in TCS than that in paired NCS were evidently identified. And low expression of IL-16 (0.14-fold decrease) and RANTES/CCL5 (0.17-fold decrease) in TCS were also uncovered. Especially, overexpression of CXCL10 in primary HCC compared with their non-tumor counterparts was significantly associated with serum AFP level (P = 0.004), tumor size (P = 0.021), tumor number (P < 0.001) and TNM stage (P = 0.027). In addition, Kaplan-Meier curves demonstrated that patients with higher CXCL10 expression levels had significantly poorer overall survival (P = 0.016) and disease-free survival (P = 0.022) than those with lower CXCL10 expression levels. Univariate and multivariate analyses revealed that the level of CXCL10 expression was an independent prognostic factor for overall survival in HCC patients. In summary, high concentration of CXCL10 is deposited in HCM identified by antibody array, which may contribute to the prediction of clinical outcome of HCC patients.

Abstract 4479: Protein arginine methyltransferase PRMT6 regulates cancer stemness through CRAF methylation in hepatocellular carcinoma

Arginine methylation is a post-translational modification that plays pivotal roles in signal transduction and gene transcription during cell fate determination. We found protein methyltransferase 6 (PRMT6) to be frequently down-regulated in hepatocellular carcinoma (HCC) cells and its expression to negatively correlate with aggressive cancer features in HCC patients. Silencing of PRMT6 promoted the tumor-initiating, metastasis and therapy resistance potential of HCC cells. Consistently, loss of PRMT6 expression aggravated liver tumorigenesis in a DEN+CCL4 HCC induced PRMT6-/- mouse model. Integrated transcriptome and protein-protein interaction studies revealed an enrichment of genes implicated in RAS signaling and that PRMT6 interacted with CRAF, and likely other RAF family members, and their methylation at conserved arginine 100, negatively regulating its activity, and as a consequence resulting in enhanced MEK/ERK signaling. Our work uncovered a critical repressive function for PRMT6 in maintenance of HCC cells by regulating the MEK/ERK pathway via arginine methylation of RAF, providing a new avenue of molecular mechanism by which ERK mediated stemness in HCC cells are developed.

Citation Format: LH Chan, L Zhou, Kai Yu Ng, TL Wong, TK Lee, YP Ching, YF Yuan, D Xie, S Richard, MS Huen, XY Guan, S Ma. Protein arginine methyltransferase PRMT6 regulates cancer stemness through CRAF methylation in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4479.

MicroRNA-377 suppresses initiation and progression of esophageal cancer by inhibiting CD133 and VEGF

Esophageal cancer is one of the most lethal cancers worldwide with poor survival and limited therapeutic options. The discovery of microRNAs created a new milestone in cancer research. miR-377 is located in chromosome region 14q32, which is frequently deleted in esophageal squamous cell carcinoma (ESCC), but the biological functions, clinical significance and therapeutic implication of miR-377 in ESCC are largely unknown. In this study, we found that miR-377 expression was significantly downregulated in tumor tissue and serum of patients with ESCC. Both tumor tissue and serum miR-377 expression levels were positively correlated with patient survival. Higher serum miR-377 expression was inversely associated with pathologic tumor stage, distant metastasis, residual tumor status and chemoradiotherapy resistance. The roles of miR-377 in suppressing tumor initiation and progression, and the underlying molecular mechanisms were investigated. Results of in vitro and in vivo experiments showed that miR-377 overexpression inhibited the initiation, growth and angiogenesis of ESCC tumors as well as metastatic colonization of ESCC cells, whereas silencing of miR-377 had opposite effects. Mechanistically, miR-377 regulated CD133 and VEGF by directly binding to their 3' untranslated region. Moreover, systemic delivery of formulated miR-377 mimic not only suppressed tumor growth in nude mice but also blocked tumor angiogenesis and metastasis of ESCC cells to the lungs without overt toxicity to mice. Collectively, our study established that miR-377 plays a functional and significant role in suppressing tumor initiation and progression, and may represent a promising non-invasive diagnostic and prognostic biomarker and therapeutic strategy for patients with ESCC.

Knock-down of p300 decreases the proliferation and odontogenic differentiation potentiality of HDPCs

AIM

To investigate the role of p300 in the regulation of proliferation and odontogenic differentiation of human dental pulp cells (HDPCs).

METHODOLOGY

The recombinant lentiviral vector pshRNA-copGFP was used to knock-down p300 expression in HDPCs. Protein level of acetylated H3 was detected. The proliferation of HDPCs was measured using the CCK8 assay. The cell cycle and apoptosis were analysed using flow cytometry and TUNEL staining, respectively. The expression levels of Cdc25A, p21(waf1) and the cleaved products of caspase 3 and caspase 7 were determined utilizing real-time quantitative polymerase chain reaction and Western blotting analysis. The alkaline phosphatase (ALP) activity was measured, and the formation of mineralized nodules was assessed using alizarin red staining after the induction of odontogenic differentiation of HDPCs. The expression levels of the odontogenic differentiation markers DMP-1, DSPP and DSP were detected utilizing real-time quantitative polymerase chain reaction and Western blotting analysis.

RESULTS

After p300 was knocked down in HDPCs, p300 was significantly down-regulated at both the mRNA and protein levels, and histone H3 acetylation was reduced. The proliferation capacity of HDPCs was suppressed in p300 knock-down groups. The cells were arrested in the G0/G1 phase of the cell cycle, and cell apoptosis was triggered. ALP activity, the formation of mineralized nodules and the expression levels of DMP-1, DSPP and DSP were all decreased in p300-knock-down HDPCs undergoing odontogenic differentiation.

CONCLUSION

Knocking down p300 restrains the proliferation and odontogenic differentiation potentiality of HDPCs.

Anti-angiogenic pathway associations of the 3p21.3 mapped BLU gene in nasopharyngeal carcinoma

Zinc-finger, MYND-type containing 10 (ZMYND10), or more commonly called BLU, expression is frequently downregulated in nasopharyngeal carcinoma (NPC) and many other tumors due to promoter hypermethylation. Functional evidence shows that the BLU gene inhibits tumor growth in animal assays, but the detailed molecular mechanism responsible for this is still not well understood. In current studies, we find that 93.5% of early-stage primary NPC tumors show downregulated BLU expression. Using a PCR array, overexpression of the BLU gene was correlated to the angiogenesis network in NPC cells. Moreover, expression changes of the MMP family, VEGF and TSP1, were often detected in different stages of NPC, suggesting the possibility that BLU may be directly involved in the microenvironment and anti-angiogenic activity in NPC development. Compared with vector-alone control cells, BLU stable transfectants, derived from poorly-differentiated NPC HONE1 cells, suppress VEGF165, VEGF189 and TSP1 expression at both the RNA and protein levels, and significantly reduce the secreted VEGF protein in these cells, reflecting an unknown regulatory mechanism mediated by the BLU gene in NPC. Cells expressing BLU inhibited cellular invasion, migration and tube formation. These in vitro results were further confirmed by in vivo tumor suppression and a matrigel plug angiogenesis assay in nude mice. Tube-forming ability was clearly inhibited, when the BLU gene is expressed in these cells. Up to 70-90% of injected tumor cells expressing increased exogenous BLU underwent cell death in animal assays. Overexpressed BLU only inhibited VEGF165 expression in differentiated squamous NPC HK1 cells, but also showed an anti-angiogenic effect in the animal assay, revealing a complicated mechanism regulating angiogenesis and the microenvironment in different NPC cell lines. Results of these studies indicate that alteration of BLU gene expression influences anti-angiogenesis pathways and is important for the development of NPC.

Hyperthyroid monkeys: a nonhuman primate model of experimental Graves' disease

Graves' disease (GD) is a common organ-specific autoimmune disease with the prevalence between 0.5 and 2% in women. Several lines of evidence indicate that the shed A-subunit rather than the full-length thyrotropin receptor (TSHR) is the autoantigen that triggers autoimmunity and leads to hyperthyroidism. We have for the first time induced GD in female rhesus monkeys, which exhibit greater similarity to patients with GD than previous rodent models. After final immunization, the monkeys injected with adenovirus expressing the A-subunit of TSHR (A-sub-Ad) showed some characteristics of GD. When compared with controls, all the test monkeys had significantly higher TSHR antibody levels, half of them had increased total thyroxine (T₄) and free T₄, and 50% developed goiter. To better understand the underlying mechanisms, quantitative studies on subpopulations of CD4+T helper cells were carried out. The data indicated that this GD model involved a mixed Th1 and Th2 response. Declined Treg proportions and increased Th17:Treg ratio are also observed. Our rhesus monkey model successfully mimicked GD in humans in many aspects. It would be a useful tool for furthering our understanding of the pathogenesis of GD and would potentially shorten the distance toward the prevention and treatment of this disease in human.

Transcriptome sequencing of sea cucumber (Apostichopus japonicus) and the identification of gene-associated markers

Sea cucumber (Apostichopus japonicus) is an ecologically and economically important species in East and South-East Asia. This project aimed to identify large numbers of gene-associated markers and differentially expressed genes (DEGs) after lipopolysaccharides (LPS) challenge in A. japonicus using high-throughput transcriptome sequencing. A total of 162 million high-quality reads of 174 million raw reads were obtained by deep sequencing using Illumina HiSeq™ 2000 platform. Assembly of these reads generated 94 704 unigenes, with read length ranging from 200 to 16 153 bp (average length of 810 bp). A total of 36 005 were identified as coding sequences (CDSs), 32 479 of which were successfully annotated. Based on the assembly transcriptome, we identified 142 511 high-quality single nucleotide polymorphisms (SNPs). Among them, 33 775, 63 120 and 45 616 were located in sequences without predicted CDS (non-CDSs), CDSs and untranslated regions (UTRs), respectively. These putative SNPs included 82 664 transitions and 59 847 transversions. Totally, 89 375 (59.1%) were distributed in 15 473 known genes. A total of 6417 microsatellites were detected in 5970 unigenes, 3216 of which were annotated and 2481 were successfully subjected for primer design. The numbers of simple sequence repeats (SSRs) identified in non-CDSs, CDSs and UTRs were 2367, 2316 and 1734. These potential SNPs and SSRs are expected to provide abundant resources for genetic, evolutionary and ecological studies in sea cucumber. Transcriptome comparison revealed 1330, 1347 and 1291 DEGs in the coelomocytes of A. japonicus at 4 h, 24 h and 72 h after LPS challenge, respectively. Approximately 58.4% (1802) of total DEGs have been successfully annotated.

Overexpression of clusterin correlates with tumor progression, metastasis in gastric cancer: a study on tissue microarrays

Clusterin (CLU) is expressed in a wide variety of human tissues and fluids. Overexpression of cytoplasmic clusterin (sCLU) has been implicated in cancer development and progression. The aim of the present study is to evaluate the association of sCLU overexpression with clinicopathological features of human gastric carcinomas (GC).We constructed a gastric cancer tissue microarray containing 173 primary gastric carcinomas and 70 paired non-neoplastic mucosa specimens. The expression of sCLU was studied by immunohistochemistry. The correlations between sCLU expression and clinicopathological features, p53 abnormality, as well as Ki67 activation were analyzed. Overexpressions of sCLU was detected in 28.5% (n=165) of primary GCs by immunohistochemical staining, but not in non-neoplastic mucosa. Clinical association study found that overexpression of sCLU was significantly correlated with lymph-node metastasis (p < 0.001), tumor invasion (p < 0.001) and TNM stage (p < 0.001). In Kaplan-Meier survival analysis, overexpression of sCLU was significantly correlated with unfavorable survival in advanced GCs (p < 0.03). Furthermore, the association of sCLU with abnormal expression of p53 was ascertained. These results suggested that overexpression of sCLU was involved in the progression of GC and it's oncogenic function might be associated with p53 abnormality. Overexpression of sCLU seems to be related with patient's shorter survival in late stage GC.

Establishment and characterization of a new xenograft-derived human esophageal squamous cell carcinoma cell line HKESC-4 of Chinese origin

A new human esophageal cancer cell line, HKESC-4, was established from a nude-mouse xenograft of a moderately differentiated esophageal squamous cell carcinoma (ESCC) developed from a 65-year-old Hong Kong Chinese man. The cellular characteristics (morphological, electron microscopic, and immunohistochemical studies), tumorigenicity in athymic nude mice, cytogenetic features, and DNA ploidy of the cell line were investigated. The cell line was maintained in vitro for 17 months and passaged 80 times. HKESC-4 grew as a monolayer, with a doubling time of 63 hours. The epithelial nature of HKESC-4 included the presence of cytokeratin intermediate filaments, as shown by antibodies (AE1/AF3, CAM5.2, and MAK 6), and the presence of the tonofilaments, as seen under electron microscopy. HKESC-4 was tumorigenic in nude mice and had DNA aneuploidy. The cytogenetic abnormalities of HKESC-4 included -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -15, -16, -17, -18, -19, +20, -21, -22, +del(11)(p11), +i(11)(q10), and +21 marker chromosomes. Comparative genomic hybridization analysis demonstrated chromosomal gains at 1p36.13, 3q23 approximately q28, 5p15.33 approximately p15.1, 6p25.1 approximately p22.3, 7p21.3 approximately p11.2, 7q11.21 approximately q21.13, 8q23.3 approximately q23.3, 11p11.2, 11q12.1 approximately q13.2, 14q21.3 approximately q32.2, 17p13.3, 18p11.32 approximately p11.31, and 20p13 approximately p12.2 and chromosomal losses at 1q12, 2p25.1 approximately p24.3, 13p13 approximately p11.2, 21p, 22p13 approximately p11.2, and Y. The newly established cell line HKESC-4 promises to be a useful tool in future studies of molecular pathogenesis and therapeutics in ESCC.

The significance of LMO2 expression in the progression of prostate cancer

LIM domain only 2 (LMO2) proteins are important regulators in determining cell fate and controlling cell growth and differentiation. This study has investigated LMO2 expression in human prostatic tissue specimens, prostate cancer cell lines, and xenografts; and has assessed the possible role and mechanism of LMO2 in prostate carcinogenesis. Immunohistochemical analysis on a tissue microarray consisting of 91 human prostate specimens, including normal, prostatic hyperplasia, high-grade prostatic intraepithelial neoplasia, and invasive carcinoma, revealed that overexpression of LMO2 was significantly associated with advanced tumour stage, as measured by Gleason score (p = 0.012), as well as with the development of distant metastasis (p = 0.018). These data were supported by quantitative real-time PCR experiments, where LMO2 mRNA levels were found to be significantly higher in prostate tumour specimen than in normal epithelium (p = 0.037). The expression of LMO2 in cell lines and xenografts representing androgen-dependent (AD) and androgen-independent (AI) prostate cancer stages was further studied. Consistent with the in vivo data, LMO2 mRNA and protein were found to be overexpressed in the more aggressive AI cells (PC3, DU145, and AI CWR22 xenografts) compared with less aggressive AD cells (LNCaP and AD CWR22 xenografts). Furthermore, stable introduction of LMO2 into LNCaP cells conferred enhanced cell motility and invasiveness in vitro, accompanied by down-regulation of E-cadherin expression. Taken together, these findings provide the first evidence to support the hypothesis that LMO2 may play an important role in prostate cancer progression, possibly via repression of E-cadherin expression.

Comparative genomic hybridization: comparison between esophageal squamous cell carcinoma and gastric cardia adenocarcinoma from a high-incidence area for both cancers in Henan, northern China

Esophageal squamous cell carcinoma (SCC) remains the leading cause of cancer related deaths in Linzhou (formerly Linxian), the highest incidence area for esophageal cancer (EC) in Henan, northern China. In China, gastric cardia adenocarcinoma (GCA) shares very similar geographic distribution with SCC, suggesting the possibility of similar risk factors involved in SCC and GCA carcinogenesis in these areas. However, the underlying genetic alterations for esophageal and gastric cardia carcinogenesis, especially for the molecular difference between SCC and GCA, are largely unknown. The present study was thus undertaken to determine the difference in chromosomal aberrations in SCC (n = 37) and GCA (n = 31) using the comparative genomic hybridization method (CGH). All the patients were from Linzhou, Henan, a high-risk geographic region for both SCC and GCA. CGH results showed that chromosomal aberrations with different degrees were identified both in SCC and GCA. In SCC, chromosomal profile of DNA copy number was characterized by most frequently detected gains at 8q (29/37, 78%), 3q (24/37, 65%) and 5p (19/37, 51%); and frequently detected losses at 3p (21/37, 57%), 8p and 9q (14/37, 38%). In GCA, the frequently detected gains were identified at 20q (13/31, 42%), 6q (12/31, 39%) and 8q (11/31, 35%); the DNA copy number losses in GCA occurred frequently at 17p (17/31, 55%), 19p (15/31, 48%) and 1p (14/31, 45%). Statistically, there were evident differences between SCC and GCA in DNA copy number gains at 8q, 3q, 5p and 20q (P < 0.05) and in losses at 3p, 8p, 5q, 17p and 18q (P < 0.05). Gains at 8q were frequently observed in both SCC and GCA. Gains at 3q and 8p were frequently observed in TNM stage III of both SCC and GCA. The present CGH results provide candidate regions that may contain specific related genes involved in SCC and GCA in the Linzhou population. Gains at 8q, 3q and 5p and losses at 3p, 8p and 9q were specifically implicated in SCC; gains at 20q, 6q and 8q and losses at 17p, 19p and 1p were specifically implicated in GCA; gains at 8q were implicated in both SCC and GCA.

Expression of cytoplasmic and nuclear Survivin in primary and secondary human glioblastoma

Clinically, human glioblastoma (GBM) may develop de novo or from a low-grade glioma (secondary GBM), and molecular alterations in the two pathways may differ. This study examined the status of Survivin expression and apoptosis in 30 primary and 26 secondary GBMs. Our results show that cytoplasmic Survivin positivity was significantly (P<0.001) more frequent in primary GBMs (83%) than that in secondary GBMs (46%). In addition, an inverse correlation of cytoplasmc Survivin positivity with GBM apoptotic index, and a positive association between cytoplasmic Survivin and size of the tumours were observed. These results suggest that cytoplasmic Survivin, via its antiapoptotic function, may be involved in the tumorigenesis of many primary GBMs, but only in a small fraction of secondary GBMs. Furthermore, the overall progression times from low-grade precursor lesions to secondary GBMs were significantly shorter (P<0.05) in cytoplasmic Survivin-positive cases (mean, 15.6 months) than those in Survivin-negative cases (mean, 23.8 moths), and the positive expression level of Survivin in cytoplasm was upregulated in most secondary GBMs when compared to matched pre-existing low-graded lesions. These results suggest that the increased accumulation of Survivin in the cytoplasm of more malignant glioma cells may prove to be a selective advantage, thus accelerating progression to a more aggressive phenotype.

Amplification and overexpression of aurora kinase A (AURKA) in immortalized human ovarian epithelial (HOSE) cells

Immortalization is an early and essential step of human carcinogenesis. Amplification of chromosome 20q has been shown to be a common event in immortalized cells and cancers. We have previously reported that gain and amplification of chromosome 20q is a non-random and common event in immortalized human ovarian surface epithelial (HOSE) cells. The chromosome 20q harbors genes including TGIF2 (20q11.2-q12), AIB1 (20q12), PTPN1 (20q13.1), ZNF217 (20q13.2), and AURKA (20q13.2-q13.3), which were previously reported to be amplified and overexpressed in ovarian cancers. Some of these genes may be involved in immortalization of HOSE cells and represent crucial premalignant changes in ovarian surface epithelium. Investigation of the involvement of these genes was examined in four pairs of pre-crisis (preimmortalized) and post-crisis (immortalized) HOSE cells. Overexpression of AURKA (Aurora kinase A), also known as BTAK and STK15, by both real time-quantitative polymerase chain reaction (RT-QPCR) and Western blotting was detected in all the four immortalized HOSE cells examined while overexpression of AIB1 and ZNF217 was observed in two of four immortalized HOSE cells examined. Overexpression of TGIF2 and PTPN1 was not significant in our immortalized HOSE cell systems. The degree of overexpression of AURKA was shown to be closely associated with the amplification of chromosome 20q in immortalized HOSE cells. Fluorescence in situ hybridization (FISH) with labeled P1 artificial clone (PAC) confirmed the amplification of the chromosomal region (20q13.2-13.3) where AURKA resides. DNA amplification of AURKA was also confirmed using semi-quantitative PCR. Our study showed that amplification and overexpression of AURKA is a common and significant event during immortalization of HOSE cells and may represent an important premalignant change in ovarian carcinogenesis.

A rat cell line derived from DMBA-induced mammary carcinoma

A new cell line, designated UHKBR-01, was successfully established from a 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumour. DMBA was administered orally at a dose of 4 mg/ml per rat on the first day of the experiment and thereafter at weekly intervals of same dosage, until the rats have reached a weight of around 150-200 g. The tumours grew rapidly after the injection, and were transplanted into nude mice one the harvest size (2.5 x 2 x 1 mm(3)) was reached, it was transplanted onto nude mice. We have developed a cell line from a portion of the DMBA-induced carcinoma of the nude mice. The UHKBR-01 cell exhibited a slow increase in growth rate during the time of culture and was highly tumourigenic in nude mice. The cells have been grown in culture for over 40 passages. Characterization of the cell line was performed. This included morphology by light and transmission electron microscopy, karyotype, growth rate, tumour antigen expression and xenograft implantation into nude mice. These cells exhibit ultrastructural and immunohistochemical features of epithelial cells of mammary origin. The above analyses also demonstrated that UHKBR-01 cells were oestrogen- and progesterone-receptor positive, in likeness to other established breast cancer cell lines such as MDA-MB-231 and MCF-7. The cell line grows as monolayers of oval-shaped cells with large folded nuclei accompanied by a rich supply of mitochondria. This report describes the first in vitro cell line from transplantable DMBA-induced mammary carcinoma of nude mice, which presents unique characteristics that may prove to be a good experimental model for investigating breast cancer biology.

Pure trisomy 10p resulting from an extra ring chromosome: characterization by methods of advanced molecular cytogenetics

With the use of advanced molecular cytogenetic techniques, we have identified an extra ring chromosome consisting of the entire short arm of chromosome 10 (10p) in a 9-month-old girl with multiple congenital anomalies. This case represents another cytogenetic mechanism leading to the formation of pure complete trisomy 10p, which has not been reported previously. Pure trisomy 10p is rare. This case will further delineate those features associated with trisomy 10p.

Chromosome 8p deletion is associated with metastasis of human hepatocellular carcinoma when high and low metastatic models are compared

Recently, we found that chromosome 8p deletion might be associated with hepatocellular carcinoma (HCC) metastasis by analyzing the differences in chromosomal alterations between primary tumors and their matched metastatic lesions of HCC with comparative genomic hybridization (CGH) (Qin et al. 1999). To further confirm this interesting finding, the genomic changes of two models bearing human HCC with different metastatic potentials (LCI-D20 and LCI-D35), and the new human HCC cell line with high metastatic potential (MHCC97) were analyzed by CGH. Gains on 1q, 6q, 7p, and 8q, and losses on 13p, 14p, 19p, 21, and 22 were detected in both LCI-D20 and LCI-D35 models. However, high copy number amplification of a minimum region at 1q12-q22 and 12q, and deletions on 1p32-pter, 3p21-pter, 8p, 9p, 10q, 14q, and 15p were detected only in the LCI-D20 model. Gains on 1p21-p32, 2p13-p21, 6p12-pter, 9p, 15q, and 16q11-q21, and losses on 2p23-pter, 4q24-qter, 7q31-qter, 12q, 17p, and 18 were detected only in the LCI-D35 model. The chromosomal aberration patterns in the MHCC97 cell line were similar to its parent LCI-D20 model, except that gains on 19q and losses on 4, 5, 10q, and 13q were found only in the cell line. These results provide some indirect clues to the metastasis-related chromosomal aberrations of HCC and further support the finding that 8p deletion is associated with HCC metastasis. 1q12-22 and 12q might harbor a novel oncogene(s) that contributes to the development and progression of HCC. Amplification on 8q and deletions on 4q and 17p may be not necessary for HCC metastasis.

Isolation of a novel candidate oncogene within a frequently amplified region at 3q26 in ovarian cancer

Amplification of 3q25-q26 was one of the most frequent chromosomal alterations in human ovarian carcinoma. A chromosome microdissection-hybrid selection method was applied to isolate transcribed sequences from a primary ovarian cancer containing high-copy-number amplification of 3q26 using 3q26 band-specific DNAs generated by chromosome microdissection. Using this method, we have isolated a novel candidate oncogene eIF-5A2 (eukaryotic initiation factor 5A2). eIF-5A2 shares 82% identity of amino acid sequence with eIF-5A including the minimum domain needed for eIF-5A maturation by hypusine modification at lysine-50 residue. Amplification and overexpression of eIF-5A2 was frequently detected in primary ovarian cancers and ovarian cancer cell lines. The proliferation-related function of eIF-5A supports that eIF-5A2 is a candidate oncogene related to the development of ovarian cancer.

Chromosome Microdissection for Detection of Subchromosomal Alterations by FISH

Chromosome microdissection is a recently developed molecular cytogenetic technique that has become increasingly important as a bridge connecting cytogenetics to molecular genetics. After a decade of effort, this approach has been developed into a useful and reproducible approach for several purposes, including 1) the isolation of DNA from any cytogenetically recognizable region which can be used to generate DNA microclone libraries for molecular analysis and positional cloning (1,2) the generation of fluorescence in situ hybridization (FISH) probes for whole chromosome painting probes (3), and chromosome arm painting probes (4) for cytogenetic study; 3) combined with FISH, microdissection has been applied to detecte virtually any kind of visible chromosome rearrangements (5,6); and more recently, 4) microdissection combined with hybrid selection has been applied to identify genes associated with homogeneously staining regions (HSRs) in human cancers (7,8).

Childhood-onset schizophrenia/autistic disorder and t(1;7) reciprocal translocation: identification of a BAC contig spanning the translocation breakpoint at 7q21

Childhood-onset schizophrenia (COS) is defined by the development of first psychotic symptoms by age 12. While recruiting patients with COS refractory to conventional treatments for a trial of atypical antipsychotic drugs, we discovered a unique case who has a familial t(1;7)(p22;q21) reciprocal translocation and onset of psychosis at age 9. The patient also has symptoms of autistic disorder, which are usually transient before the first psychotic episode among 40-50% of the childhood schizophrenics but has persisted in him even after the remission of psychosis. Cosegregating with the translocation, among the carriers in the family available for the study, are other significant psychopathologies, including alcohol/drug abuse, severe impulsivity, and paranoid personality and language delay. This case may provide a model for understanding the genetic basis of schizophrenia or autism. Here we report the progress toward characterization of genomic organization across the translocation breakpoint at 7q21. The polymorphic markers, D7S630/D7S492 and D7S2410/D7S646, immediately flanking the breakpoint, may be useful for further confirming the genetic linkage for schizophrenia or autism in this region. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:749-753, 2000. Published 2000 Wiley-Liss, Inc.

Recurrent chromosome changes in 62 primary gastric carcinomas detected by comparative genomic hybridization

Comparative genomic hybridization (CGH) has been applied to detect recurrent chromosome alterations in 62 primary gastric carcinomas. Several nonrandom chromosomal changes, including gains of 8q (31 cases, 50%), 20q (29 cases, 47%) with a minimum gain region at 20q11. 2-q12, 13q (21 cases, 34%) with a minimum gain region at 13q22, and 3q (19 cases, 31%) were commonly observed. The regions most frequently lost included: 19p (23 cases, 37%), 17p (21 cases, 33%), and 1p (14 cases, 23%). High copy number gain (DNA sequence amplification) was detected in 6 cases. Amplification of 8q23-q24.2 and 20q11.2-q12 were observed in 3 cases. Gain of 20q and loss of 19p were confirmed by fluorescence in situ hybridization using corresponding bacterial artificial chromosomes (BAC) clones from those regions. The gain and loss of chromosomal regions identified in this study provide candidate regions involved in gastric tumorigenesis.

Recurrent chromosome alterations in hepatocellular carcinoma detected by comparative genomic hybridization

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and has a very poor prognosis. Fifty primary HCC cases have been analyzed in the present study to explore the association between genomic alteration in primary HCC and clinical features. Several recurrent chromosomal abnormalities were identified in this study. The most frequently detected chromosomal gains involved chromosome arms 1q (33/50 cases, 66%), 8q (24/50 cases, 48%), and 20q (10/50 cases, 20%). High-copy-number amplifications involving 1q (4 cases), 8q (3 cases), and 20q (3 cases) were detected, and a minimum overlapping amplified region at 1q12-q22 was identified. The most frequently detected loss of chromosomal material involved 16q (35/50 cases, 70%), 17p (26/50 cases, 52%), 19p (21/50 cases, 42%), 4q (20/50 cases, 40%), 1p (18/50 cases, 36%), 8p (16/50 cases, 32%), and 22q (14/50 cases, 28%). The associations between genomic alterations detected in the present study and clinical features including clinical stage, tumor size, HBV infection, chronic liver disease, and liver cirrhosis were explored. Our CGH results suggest that the gain of 20q and deletion of 8p are late genetic alterations in HCC, because the incidence of these alterations was obviously increased in the advanced clinical stages. Another finding showed that loss of 8p and gain of 8q and 20q are associated with tumor size. The recurrent gain and loss of chromosomal regions identified in this study provide candidate regions that may contain oncogenes or tumor suppressor genes respectively involved in HCC development and progression.

A nuclear factor, ASC-2, as a cancer-amplified transcriptional coactivator essential for ligand-dependent transactivation by nuclear receptors in vivo

Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. We isolated a nuclear factor (designated ASC-2) with such properties by using the ligand-binding domain of retinoid X receptor as a bait in a yeast two-hybrid screening. ASC-2 also interacted with other nuclear receptors, including retinoic acid receptor, thyroid hormone receptor, estrogen receptor alpha, and glucocorticoid receptor, basal factors TFIIA and TBP, and transcription integrators CBP/p300 and SRC-1. In transient cotransfections, ASC-2, either alone or in conjunction with CBP/p300 and SRC-1, stimulated ligand-dependent transactivation by wild type nuclear receptors but not mutant receptors lacking the AF2 domain. Consistent with an idea that ASC-2 is essential for the nuclear receptor function in vivo, microinjection of anti-ASC-2 antibody abrogated the ligand-dependent transactivation of retinoic acid receptor, and this repression was fully relieved by coinjection of ASC-2-expression vector. Surprisingly, ASC-2 was identical to a gene previously identified during a search for genes amplified and overexpressed in breast and other human cancers. From these results, we concluded that ASC-2 is a bona fide transcription coactivator molecule of nuclear receptors, and its altered expression may contribute to the development of cancers.

The association of chromosome 8p deletion and tumor metastasis in human hepatocellular carcinoma

To understand the genetic mechanisms underlying the progression of hepatocellular carcinoma (HCC) metastasis, differences of genomic alterations between 10 pairs of primary HCC tumors and their matched metastatic lesions were analyzed by comparative genomic hybridization. Several chromosomal alterations including loss of 8p, 4q, 17p, and 19p, gain of 5p and high-level amplification of 1q12-q22 were detected in two or more cases. The most significant finding is the loss of 8p which was detected in 8 metastatic tumors but only in 3 corresponding primary tumors (P = 0.03). This result suggests that the deletion of chromosome 8p might contribute to the development of HCC metastasis. Another interesting result is the detection of a minimum high-level amplification region at 1q12-q22 in HCC. This result provides a candidate amplification region in HCC for further study to identify amplified oncogenes related to the development or progression of HCC. Finally, this study provides a practicable model to detect specific genetic alterations related to the tumor metastasis through comparing the primary tumor and its corresponding metastatic lesion using comparative genomic hybridization technique.

Origins of accessory small ring marker chromosomes derived from chromosome 1

Three patients with accessory small ring chromosomes derived from chromosome 1 are presented together with additional clinical details and cytogenetic analyses of a previously reported patient. Cytogenetic analysis was undertaken by FISH using a reverse painting probe generated from one of the patients by microdissection of the r(1) chromosome and with a BAC923C6 which maps to 1p12. Results indicated that patients with r(1) chromosomes consisting of 1q12 heterochromatin and short arm pericentric euchromatin which extends to at least the BAC923C6 were associated with a normal or mild phenotype. Patients with abnormal phenotypes possessed two types of rings. One patient had evidence for contiguous pericentric short arm euchromatin which extended from the centromere to beyond the BAC923C6. Two patients showed molecular cytogenetic results which were compatible with non-contiguous chromosome 1 euchromatin. The diversity of origin of r(1)s will hamper attempts to define phenotype/genotype relationships.

Isolation of human transcripts expressed in hamster cells from YACs by cDNA representational difference analysis

Gene isolation methods used during positional cloning rely on physical contigs consisting of bacterial artificial chromosomes, P1, or cosmid clones. However, in most instances, the initial framework for physical mapping consists of contigs of yeast artificial chromosome (YACs), large vectors that are suboptimal substrates for gene isolation. Here we report a strategy to identify gene sequences contained within a YAC by using cDNA representational difference analysis (RDA) to directly isolate transcripts expressed from the YAC in mammalian cells. The RDA tester cDNAs were generated from a previously reported hamster cell line derived by stable transfer of a 590-kb YAC (911D5) that expressed NPC1, the human gene responsible for Niemann-Pick type C (NP-C). The driver cDNAs were generated from a control hamster cell line that did not contain the YAC that expressed NPC1. Among the gene fragments obtained by RDA, NPC1 was the most abundant product. In addition, two non-NPC1 fragments were isolated that were mapped to and expressed from 911D5. One of these RDA gene fragments (7-R) spans more than one exon and has 98% sequence identity with a human cDNA clone reported previously as an expressed sequence tag (EST), but not mapped to a chromosomal region. The other fragment (2-R) that had no significant sequence similarities with known mammalian genes or ESTs, was further localized to the region of overlap between YACs 911D5 and 844E3. The latter YAC is part of a contig across the NP-C candidate region, but does not contain NPC1. This two-part approach in which stable YAC transfer is followed by cDNA RDA should be a useful adjunct strategy to expedite the cloning of human genes when a YAC contig is available across a candidate interval.

Identification of a ring chromosome in a myxoid malignant fibrous histiocytoma with chromosome microdissection and fluorescence in situ hybridization

We investigated the origin of a ring chromosome in a myxoid malignant fibrous histiocytoma (MFH) by microdissection and fluorescence in situ hybridization (FISH) analyses. Cytogenetically, only two ring chromosomes were observed; the smaller ring was seen more frequently. The latter was microdissected, and the material used for FISH. Hybridization of the microdissected labeled DNA to normal metaphase cells revealed that the signal localized only to 20q. Three signals were seen in the tumor cells using either the microdissected 20q probe or chromosome 20 centromeric probe, indicating the involvement of both the long arm and the centromere in the ring chromosome. The short arm of chromosome 20 did not appear to be involved in the formation of the ring chromosome.

Human artificial chromosomes generated by modification of a yeast artificial chromosome containing both human alpha satellite and single-copy DNA sequences

A human artificial chromosome (HAC) vector was constructed from a 1-Mb yeast artificial chromosome (YAC) that was selected based on its size from among several YACs identified by screening a randomly chosen subset of the Centre d'Etude du Polymorphisme Humain (CEPH) (Paris) YAC library with a degenerate alpha satellite probe. This YAC, which also included non-alpha satellite DNA, was modified to contain human telomeric DNA and a putative origin of replication from the human beta-globin locus. The resultant HAC vector was introduced into human cells by lipid-mediated DNA transfection, and HACs were identified that bound the active kinetochore protein CENP-E and were mitotically stable in the absence of selection for at least 100 generations. Microdissected HACs used as fluorescence in situ hybridization probes localized to the HAC itself and not to the arms of any endogenous human chromosomes, suggesting that the HAC was not formed by telomere fragmentation. Our ability to manipulate the HAC vector by recombinant genetic methods should allow us to further define the elements necessary for mammalian chromosome function.

A targeted disruption of the murine Brca1 gene causes gamma-irradiation hypersensitivity and genetic instability

Germline mutations of the Brcal gene are responsible for most cases of familial breast and ovarian cancers, but somatic mutations are rarely detected in sporadic events. Moreover, mouse embryos deficient for Brca1 have been shown to die during early embryogenesis due to a proliferation defect. These findings seem incompatible with the tumor suppress function assigned to this gene and raise questions about the mechanism by which Brca1 mutations cause tumorigenesis. We now directly demonstrate that BRCA1 is responsible for the integrity of the genome. Murine embryos carrying a Brca1 null mutation are developmentally retarded and hypersensitive to gamma-irradiation, suggesting a failure in DNA damage repair. This notion is supported by spectral karyotyping (SKY) of metaphase chromosomes, which display numerical and structural aberrations. However, massive chromosomal abnormalities are only observed when a p53-/- background is introduced. Thus, a p53 dependent cell cycle checkpoint arrests the mutant embryos and prevents the accumulation of damaged DNA. Brca1-/- fibroblasts are not viable, nor are Brca1-/-:p53-/- fibroblasts. However, proliferative foci arise from Brca1-/-: p53-/- cells, probably due to additional mutations that are a consequence of the accumulating DNA damage. We believe that the increased incidence of such additional mutations accounts for the mechanism of tumorigenesis associated with Brca1 mutations in humans.

Detection of chromosome 6 abnormalities in melanoma cell lines by chromosome arm painting probes

Chromosome 6 abnormalities, particularly the deletion of 6q, are among the most frequent chromosomal changes in human malignant melanoma. In this study, chromosome 6 rearrangements in 21 melanoma cell lines were identified by fluorescence in situ hybridization (FISH) with the use of chromosome 6 arm specific painting probes (CAPs). Structural abnormalities of chromosome 6 were detectable in 18 of 21 (86%) cases, including the identification of structural abnormalities that were not detectable by routine G-banding analysis. The results of this study correlate the frequency of 6q alterations and demonstrate that FISH with CAPs can be of considerable use for rapid screening of specific chromosome abnormalities in melanoma.

Microdissection of pig chromosomes: dissection of whole chromosomes, arms and bands for construction of paints and libraries

Chromosome microdissection is an important means to efficiently generate a large number of markers from a desired region of a genome. The present study was designed to initiate microdissection and amplification of DNA from whole chromosomes, arms, or bands of porcine chromosomes. The following pig (SSC) chromosomes/segments were scraped: SSC1p, SSC1q26-q2.13, SSC2q11-q14, SSC4q12-q25, SSC13, SSC13q12-q31, SSC13q32-q43, SSC13q32-q43, SSC15, and SSC16q21-q23. After amplification and PCR-labelling, the DNA from the dissected segments were painted back to normal metaphase chromosomes to test their identity. Microdissection of some of the segments (on SSC4, 13 and 15) coincides with the mapping of economically important traits. As a first step towards generation of markers, microcloning of amplified product from SSC1p and SSC15 was carried out. The libraries were screened with a (GT)15 oligonucleotide probe. Future prospects of such a work in farm animals are discussed.

Gain of 9p in the pathogenesis of polycythemia vera

Polycythemia vera (PV) is a clonal stem cell disorder characterized by excessive erythrocyte production, resulting in absolute erythrocytosis. No specific structural chromosomal abnormalities have been reported in PV to date. We have observed two cases of PV with an extra i(9)(p10) as the sole anomaly, and FISH analysis using a 9p-specific chromosome microdissection probe showed that two other PV patients previously identified as having an add(18p) and an add(1p) as the primary changes actually carried a der(18)t(9;18)(p12;p11.2) and a der(1)t(1;9)(p12;p12), respectively. The same FISH assay was employed to evaluate domain signals on interphase cells of 15 more cases of PV with normal karyotypes and five normal controls. Two patients were observed with a significant increase in the percentage of cells with three domain signals. Our results strongly indicate that an additional i(9)(p10) is a new and recurrent primary chromosome anomaly in PV, and, in consideration of trisomy 9 being one of the most common anomalies in PV, amplification of a gene or genes on 9p, but not on 9q, may play a crucial role in the pathogenesis of PV.

Chromosome 22q11.2 interstitial deletions among childhood-onset schizophrenics and "multidimensionally impaired"

Since its first description almost a century ago schizophrenia with childhood onset, a rare yet devastating disorder, has been diagnosed in children as young as age 5. Recently, the velocardiofacial syndrome, whose underlying cause is interstitial deletions of 22q11.2, was found in 2 of 100 cases of schizophrenics with adult onset [Karayiorgou et al., Proc Natl Acad Sci USA 92: 7612-7616, 1995]. No study has documented the prevalence of velocardiofacial syndrome and the 22q11.2 deletion in a population of schizophrenics with childhood onset. Here we describe the result of such a study in a sample originally selected for a trial of atypical antipsychotic drugs. A separate group of patients was also included in the study; they can best be accounted for as a variant of childhood-onset schizophrenia (COS) and had been provisionally termed "multidimensionally impaired." Fluorescent in situ hybridization screening of 32 COS and 21 multidimensionally impaired patients revealed 1 COS patient with an interstitial deletion spanning at least 2.5 megabases.

Zoo-FISH with microdissected arm specific paints for HSA2, 5, 6, 16, and 19 refines known homology with pig and horse chromosomes

Microdissected arm specific paints (ASPs) for human (HSA) chromosomes (Chrs) 2, 5, 6, 16, and 19 were used as probes on pig (SSC) and horse (ECA) metaphase chromosomes. Regions homologous to individual human arms were delineated in the two species studied. Of the ten ASPs used, HSA6 and 16 ASPs showed complete synteny conservation of individual arms as single blocks/ arms both in pig and horse. A similar trend was, in general, also observed for HSA19 ASPs. However, contrary to these observations, synteny conservation of individual arms of HSA2 and HSA5 was not observed in pig and horse. The arm specific painting data, coupled with the available gene mapping data, showed that, although HSA2 corresponded to two arms/chromosomes each in pig and horse, the breakpoint of this synteny in humans was not located at the centromere, but at HSA2q13 band. Similarly, arm specific paints for HSA5 showed that of the two blocks/ chromosomes painted in pig and horse, one corresponded to HSA5q13-pter, the other to HSA5q13-qter. The findings suggest that 5q13 band may also be an evolutionary break point, similar to the one detected on HSA2q13. The microdissected human arm specific painting probes used in the present work provide more accurate and refined comparative information on pig and horse chromosomes than that available through the use of human whole chromosome specific paints.

AIB1, a steroid receptor coactivator amplified in breast and ovarian cancer

Members of the recently recognized SRC-1 family of transcriptional coactivators interact with steroid hormone receptors to enhance ligand-dependent transcription. AIB1, a member of the SRC-1 family, was cloned during a search on the long arm of chromosome 20 for genes whose expression and copy number were elevated in human breast cancers. AIB1 amplification and overexpression were observed in four of five estrogen receptor-positive breast and ovarian cancer cell lines. Subsequent evaluation of 105 unselected specimens of primary breast cancer found AIB1 amplification in approximately 10 percent and high expression in 64 percent of the primary tumors analyzed. AIB1 protein interacted with estrogen receptors in a ligand-dependent fashion, and transfection of AIB1 resulted in enhancement of estrogen-dependent transcription. These observations identify AIB1 as a nuclear receptor coactivator whose altered expression may contribute to development of steroid-dependent cancers.

Maternal balanced translocation leading to partial duplication of 4q and partial deletion of 1p in a son: cytogenetic and FISH studies using band-specific painting probes generated by chromosome microdissection

A 9-month-old boy with pre- and post-natal growth retardation, microcephaly, plagiocephaly, and several minor anomalies had the initial karyotype: 46,XY,der(1)t(1;?) (p36.1;?). Further analysis showed that the der(1) was derived from an unfavorable segregation of a maternal complex chromosome rearrangement, i.e., 46,XX,der(1)t(1;?) (p36.1;?), der(4)t(4;?)(q?;?). Whole chromosome fluorescence in situ hybridization (FISH) and chromosome microdissection were used to clarify the maternal karyotype as: 46,XX,der(1)t(1;4)(4qter-->4q33::1p36.13-->1qter),der( 4)t(1;4)inv(4)(4pter-->4q31.3::1p36.33-->1p36.13::4q33 -->4q31.3::1p36.33-->1pter). Therefore, the karyotype of the boy actually was 46,XY,der(1)t(1;4) (p36.13;q33). Clinical comparison of the patient's clinical findings showed similarities to individuals with partial del(1p) and dup(4q). To our knowledge the above cytogenetic abnormalities have not been described previously. This case further demonstrates the advantages of chromosome microdissection and FISH in the identification of anomalous chromosome regions and breakpoints.

Increased chromosome 20 copy number detected by fluorescence in situ hybridization (FISH) in malignant melanoma

DNA amplification is an important mechanism of tumor progression that allows cancer cells to up-regulate the expression of critical genes such as oncogenes and genes conferring drug resistance. Recent studies using comparative genomic hybridization (CGH) revealed increased DNA copies of 20q sequences in 7 melanoma cell lines and B archival metastatic melanoma lesions. To evaluate chromosome 20 abnormalities in more detail and to resolve discrepancies between karyotype and CGH findings, we performed FISH analysis of metaphase cells in 13 melanoma cell lines (including the 7 lines used for CGH) and 9 primary melanoma specimens by using a whole chromosome paint specific for chromosome 20. All 13 cell lines (100%) and 8/9 primary tumors (89%) showed extra copies of chromosome 20 relative to tumor ploidy. Additionally, 6/14 cell lines (43%) and 2/8 primary tumors (25%) showed translocated chromosome 20 material previously undetected by standard cytogenetics. Cytologic evidence for gene amplification was also found in one cell line, which contained an add(20)(p13), with additional DNA being derived from 20q sequences. These data suggest that overrepresentation of a gene or genes important for melanoma pathogenesis resides on the long arm of chromosome 20.

Identification of region specific genes by chromosome microdissection

Chromosome microdissection is an extremely useful molecular cytogenetic tool for the characterization of chromosomal abnormalities in tumor cells. Although it has been used primarily in conjunction with fluorescence in situ hybridization (FISH), microdissection has also been useful for molecular analysis via microclone library construction. Recently, microdissection has been applied to the isolation of region specific cDNAs with sufficient success that gene discovery can now be added to the list of applications of this versatile molecular cytogenetic technique.

Expression of the zinc finger gene EVI-1 in ovarian and other cancers

The EVI-1 gene was originally detected as an ectopic viral insertion site and encodes a nuclear zinc finger DNA-binding protein. Previous studies showed restricted EVI-1 RNA or protein expression during ontogeny; in a kidney and an endometrial carcinoma cell line; and in normal murine oocytes and kidney cells. EVI-1 expression was also detected in a subset of acute myeloid leukaemias (AMLs) and myelodysplasia. Because EVI-1 is expressed in the urogenital tract during development, we examined ovarian cancers and normal ovaries for EVI-1 RNA expression using reverse transcription polymerase chain reaction (RT-PCR) and RNAase protection. Chromosome abnormalities were examined using karyotypes and whole chromosome 3 and 3q26 fluorescence in situ hybridisation (FISH). RNA from six primary ovarian tumours, five normal ovaries and 47 tumour cell lines (25 ovarian, seven melanoma, three prostate, seven breast and one each of bladder, endometrial, lung, epidermoid and histiocytic lymphoma) was studied. Five of six primary ovarian tumours, three of five normal ovaries and 22 of 25 ovarian cell lines expressed EVI-1 RNA. A variety of other non-haematological cancers also expressed EVI-1 RNA. Immunostaining of ovarian cancer cell lines revealed nuclear EVI-1 protein. In contrast, normal ovary stained primarily within oocytes and faintly in stroma. Primary ovarian tumours showed nuclear and intense, diffuse cytoplasmic staining. Quantitation of EVI-1 RNA, performed using RNAase protection, showed ovarian carcinoma cells expressed 0 to 40 times the EVI-1 RNA in normal ovary, and 0-6 times the levels in leukaemia cell lines. Southern analyses of ovarian carcinoma cell lines showed no amplification or rearrangements involving EVI-1. In some acute leukaemias, activation of EVI-1 transcription is associated with translocations involving 3q26, the site of the EVI-1 gene. Ovarian carcinoma karyotypes showed one line with quadruplication 3(q24q27), but no other clonal structural rearrangements involving 3q26. However, whole chromsome 3 and 3q26 FISH performed on lines with high EVI-1 expression showed translocations involving chromosome 3q26. EVI-1 is overexpressed in ovarian cancer compared with normal ovaries, suggesting a role for EVI-1 in solid tumour carcinogenesis or progression. Mechanisms underlying EVI-1 overexpression remain unclear, but may include rearrangements involving chromosome 3q26.

Nuclear architecture and the induction of chromosomal aberrations

Progress in fluorescence in situ hybridization, three dimensional microscopy and image analysis has provided the means to study the three-dimensional structure and distribution of chromosome territories within the cell nucleus. In this contribution, we summarize the present state of knowledge of the territorial organization of interphase chromosomes and their topological relationships with other macromolecular domains in the human cell nucleus, and present data from computer simulations of chromosome territory distributions. On this basis, we discuss models of chromosome territory and nuclear architecture and topological consequences for the formation of chromosome exchanges.

Characterization of familial partial 10p trisomy by chromosomal microdissection, FISH, and microsatellite dosage analysis

Unbalanced translocations are a frequent cause of multiple congenital anomalies in children. Translocations as small as 2-5 Mb of DNA are detectable by G-banding under optimal conditions. Some of these small translocations are visible but cannot be characterized cytogenetically due to the lack of characteristic banding on Giemsa preparations. We have combined chromosomal microdissection and fluorescence in situ hybridization (FISH) to identify the origin of a small translocated segment in three members of a family with a derivative chromosome 9 and multiple anomalies, including several ophthalmologic anomalies. We microdissected the abnormal region of the derivative 9 chromosome and used this DNA to generate a FISH probe. This probe hybridized to distal 10p on the metaphase spread of the proband, indicating the origin of the translocated segment. A whole 10p FISH probe confirmed the origin by hybridizing to the translocated segment of the derivative chromosome. FISH was then performed with a whole chromosome 9 painting probe and excluded the presence of a reciprocal, balancing translocation. We then studied the chromosome 10 partial duplication with microsatellite markers to better characterize the chromosomal segment that caused these phenotypic features. By examining the involved areas with distal 10p and 9p microsatellite markers, we were able to demonstrate a minimum of 9 Mb of trisomic 10p DNA with a chromosomal breakpoint between 10p14-10p15. We then compared this family's clinical findings to those of individuals with partial 10p trisomy who had been reported in the literature. The clinical phenotypes seen in this family are similar to, but milder than, the phenotypes of persons with the larger partial trisomies of 10p that were diagnosable by cytogenetic analysis alone. This study shows that microdissection and DNA markers can be used to precisely define small translocations that are difficult to identify by conventional G-banded chromosome analysis.

Localization by chromosome microdissection of a recurrent breakpoint region on chromosome 6 in human B-cell lymphoma

Deletion of the long arm of chromosome 6 (6q) is one of the most common chromosomal alterations in human B-cell lymphomas. Conventional cytogenetic banding analysis and loss-of-heterozygosity (LOH) studies have detected several common regions of deletion ranging across the entire long arm (6q), with no defined recurrent breakpoint yet identified. We describe here a strategy combining chromosome microdissection and fluorescence in situ hybridization (Micro-FISH) to determine a minimal region of deletion along chromosome 6. Seven clinical cases and one cell line of follicular lymphoma containing a t(14;18) and one case of diffuse lymphoma, also with a t(14;18), were used for this study. All nine cases had previously defined abnormalities of chromosome 6 determined by cytogenetic analysis. The results of chromosome dissection were unexpected and in contrast to the suggestion of disparate breakpoints by conventional chromosome banding. Specifically, Micro-FISH analysis provided evidence for a common breakpoint at 6q11 in seven of nine cases. After Micro-FISH analysis, all of the presumed simple deletions of chromosome 6 were carefully reanalyzed and shown to actually represent either nonreciprocal translocations (three cases), interstitial deletions (five cases), or isochromosome (one case). The recurrent proximal breakpoint (6q11) was detected in seven of nine cases, with the minimal region of deletion encompassing 6q11 to 6q21. By analogy to other tumor systems, the identification of recurring breakpoints within 6q11 may suggest that a gene(s) important to the genesis or progression of follicular lymphoma can be localized to this band region.

Hybrid selection of transcribed sequences from microdissected DNA: isolation of genes within amplified region at 20q11-q13.2 in breast cancer

In human breast carcinomas, increased copy number of DNA sequences derived from the long arm of chromosome 20 (20q) has been commonly observed by both chromosome microdissection and comparative genomic hybridization. This chromosomal region is likely to contain one or more genes that are the biological targets of this amplification event. We describe here the utilization of a chromosome microdissection-hybrid selection strategy to isolate transcribed sequences from microdissected homogeneously staining regions encompassing 20q. Using this strategy, we have isolated three novel amplified genes (termed AIB1, AIB3, and AIB4) from a cDNA library constructed from the 20q amplified breast cancer cell line BT-474. These three genes were mapped to 20q11 (AIB3 and AIB4) and 20q12 (AIB1) by fluorescence in situ hybridization. Our results indicate an unsuspected complexity to the amplification pattern of 20q in breast cancer and provide probes that will be useful for further characterization of tumor specimens.

Independent amplification and frequent co-amplification of three nonsyntenic regions on the long arm of chromosome 20 in human breast cancer

DNA amplification at 20q13.2 is common in breast cancer, correlates with poor prognosis, and may reflect location of an important oncogene. Recently, other regions along 20q were also found to undergo amplification. Here, amplification levels and patterns of co-amplification were analyzed by interphase fluorescence in situ hybridization at 14 loci along 20q in 146 uncultured breast carcinomas and 14 cell lines. Three regions were independently amplified in uncultured tumors: RMC20C001 region at 20q13.2 (highly amplified in 9.6% of the cases), PTPN1 region 3 Mb proximal (6.2%), and AIB3 region at 20q11 (6.2%). Co-amplifications involving two or three of these regions were seen in 11 of the 19 highly amplified tumors. The results suggest that three distinct nonsyntenic regions along 20q may be important and that complex chromosomal rearrangements underlie their frequent co-amplification in breast cancer.