From November 1999 to December 2001, three outbreaks of adenovirus (Ad) respiratory infection occurred in southern Taiwan. To determine the circulating serotypes and molecular epidemiology, a total of 524 virus strains were randomly selected from 1,064 strains isolated from 1981 to 2001, and were studied using restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR)-RFLP. The major subgenus found was subgenus B (45%), followed by subgenus E (29%) and subgenus C (25%). Ad3 and Ad7 were the major types found during the 1st outbreak, which occurred from November 1999 to March 2000, while Ad4 was found mainly during the 2nd and 3rd outbreaks in October 2000 and September 2001, respectively. Both Ad7 and Ad4 were reemerged serotypes, whereas Ad3 was consistently isolated during the survey, although it declined drastically from 36 to 2% in 2001. Genotype analysis in this study showed that the only strain of Ad7 found in 1983 was Ad7a, but all randomly selected strains of Ad7 isolated during 1999-2000 were Ad7b. The clinical features of 217 patients were analyzed during the 1999-2000 outbreaks. About 79% of the total cases were less than 7 years old. The ratio of male to female was 2:1. Severe infections, such as pneumonia and acute bronchitis, accounted for nearly half of the cases (43%). These results show the reemergence and changing of serotypes, the clinical association of respiratory adenovirus infections, and the molecular epidemiology of Ad7 genotypes in Taiwan during the past two decades.

Co-amplification and co-overexpression of ErbB2 and Grb7 are frequently found in various cancers, including breast cancer. Biochemical and functional correlations of the two molecules have identified Grb7 to be a pivotal mediator downstream of ErbB2-mediated oncogenesis. However, it remains largely unknown how Grb7 is involve in the ErbB2-mediated tumorigenesis. In this study, we show that Grb7-mediated cell proliferation and growth are essential for the tumorigenesis that occurs in ErbB2-Grb7-overexpressing breast cancer cells. Intrinsically, EGF-induced de novo Grb7 tyrosine phosphorylation/activation recruits and activates Ras-GTPases and subsequently promotes the phosphorylation of ERK1/2, thereby stimulating tumor growth. Furthermore, we also found the anti-tumor effect could be synergized by co-treatment with Herceptin plus Grb7 knockdown in Sk-Br3 breast cancer cells. Our findings illustrate an underlying mechanism by which Grb7 promotes tumorigenesis through the formation of a novel EGFR-Grb7-Ras signaling complex, thereby highlighting the potential strategy of targeting Grb7 as an anti-breast cancer therapy.Growth factor receptor-bound protein-7 (Grb7) 2 is the prototype of an emerging adaptor protein family that includes Grb10 and Grb14 and contains an N-terminal proline-rich region followed by a putative RA (Ras-associating) domain, a central PH (pleckstrin homology) domain, a BPS (Between the PH and SH2 domains), motif and a C-terminal SH2 domain (1, 2). Most of these domains are known to interact with a variegated spectrum of receptors and/or regulators, through which Grb7 is capable of activating versatile signal transduction pathways to modulate various cellular functions (1, 2). For instance, the SH2 domain of Grb7 is capable of binding to the phosphotyrosine sites of receptor tyrosine kinases such as ErbB family receptors, PDGF receptor, Tek/Tie2, c-Kit, and EphB1, as well as cytoplasmic proteins such as SHPTP2, Shc, and FAK (focal adhesion kinase) (2). The PH domain is the calmodulin-or phosphoinositide-binding domain that is responsible for plasma membrane localization and is also accessible for phosphorylation by FAK (3, 4). Structural prediction and biochemical validation both support the direct interaction of the RA domain with Ras-GTPases, similar to the canonical ubiquitin-like folded Ras-binding domain of c-Raf and RalGDS (5). Using yeast two-hybrid screening, Tankyrase 2, an ankyrin repeat-containing poly(ADP-ribose) polymerase, was identified to interact with the N-terminal prolinerich region of Grb14 (6). However, the downstream signaling targets of the identified interactions and their corresponding functional consequences remain largely unknown.Originally identified as an activated EGF receptor-binding partner, Grb7 has often been found to be co-amplified with ErbB2 in several cancers because both genes are located in the chromosome 17q12 (7). In fact, Grb7 is concurrently overexpressed with ErbB2 in about 30% of human breast cancers, and in these cases, the patients present a poor ...

Taiwan suffered a severe and widespread outbreak of enterovirus infection in 1998. More than 400 children were hospitalized, with seventy-eight fatalities due to central nerve system (CNS) involvement and cardiopulmonary collapse. Enterovirus 71 (EV71) was incriminated as the causative agent for the fatal cases. To understand the viral molecular epidemiology in this outbreak, fragments of 207-bp length of the VP4 region in 23 Taiwanese EV 71 isolates were sequenced. Pair-wise comparison revealed a 17.5-24.4% difference between the isolates and the prototype BrCr. However, all the changes in the VP4 region of the isolated strains were synonymous substitutions. Phylogenetic analysis was performed on these 23 isolates and 21 others deposited in GenBank. In this study, forty-four EV71 isolates from the world were separated into three distinct genotypes: A, B and C. The EV71 prototype strain, BrCr/70, is the only strain of genotype A. Group B included strains from the United States, Japan and Taiwan. Most strains in genotype B were isolated prior to 1990. Group C consisted of strains from Japan and Taiwan. Most strains of genotype C were isolated after 1990, they were further divided into 3 clusters: i.e. C-1, C-2 and C-3. In Taiwan, two genotypes, B and C-3, were co-circulating during the outbreak in 1998, although a minor group of genotype B may have appeared in Taiwan before 1986. The majority of the isolates clustered in genotype C-3. Genotype C showed a higher evolutionary rate than genotype B (3.9 x 10(-3) vs. 1.4 x 10(-3)) in the VP4 region. There seems to be a worldwide trend with strains of genotype B appearing earlier than strains of genotype C which took over later in the dominance.

Focal adhesion kinase (FAK) has been implicated in tumorigenesis in various cancers; however, it remains unclear how FAK participates in tumor malignancy in vivo. This study seeks to understand the role of FAK activation in gastric cancer progression. Using immunohistochemical staining and Western blotting, we found that pY397 FAK, an autophosphorylation site on FAK activation, was abundant in the cancerous tissues of 21 of 59 patients with gastric carcinomas. We attempted to correlate clinicopathological parameters, including histological types, TNM staging, and cancer recurrence, with the expression of FAK and pY397 FAK in cancerous tissues. Intriguingly, patients with higher levels of pY397 FAK displayed higher incidences of gastric cancer recurrence after surgery and poor 5-year recurrence-free survival. Furthermore, multivariate analyses showed that pY397 FAK was an independent predictor of gastric cancer recurrence. As a result, expression of pY397 FAK is a significant prognostic factor for the recurrence of gastric cancer. Additionally, in vitro studies showed that overexpression of Y397F, a dominant-negative mutant of FAK, in AGS human gastric carcinoma cells impaired cell migration, invasion, and proliferation compared with cells overexpressing wild-type FAK. Thus, activation of FAK through autophosphorylation at Tyr397 leads to the progression of gastric carcinomas by promoting cell migration, invasion, and proliferation. Collectively, our results have provided valuable insights for the development of novel diagnoses and therapeutic targets for gastric cancer treatments.

β4 integrin and focal adhesion kinase (FAK) are often associated with a poor prognosis in cancer patients, and their signaling events have recently been linked to malignant outcomes. Here, we demonstrate, for the first time, physical and functional interactions between β4 integrin and FAK that influence breast cancer malignancy. An amino-terminal linker within FAK is essential for its binding with the cytodomain of β4 integrin. Moreover, EGFR/Src-signaling triggers the tyrosine phosphorylation of β4 integrin, which, in turn, recruits FAK to β4 integrin and leads to FAK activation and signaling. Upon disruption of the β4 integrin/FAK complex, tumorigenesis and metastasis in triple-negative breast cancer were markedly reduced. Importantly, the concomitant overexpression of β4 integrin and FAK significantly correlates with malignant potential in patients with triple-negative breast cancer. This study describes a pro-metastatic EGFR/Src-dependent β4 integrin/FAK complex that is involved in breast cancer malignancy and is a novel therapeutic target for triple-negative breast cancer.

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Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v) reappeared in Taiwan in 1990 and 1994, following the first two epidemics of 1985--86 and 1988--89. To analyze the genetic diversity of recent CA24v in Taiwan, 7 Taiwanese strains isolated during the 1990--94 period were studied together with one Japanese and two Thai strains isolated in 1993. A fragment of 674 nucleotides between the carboxy terminal 3A and the amino terminal 3D polymerase, including the entire 3C protease (3C(pro)), was amplified by a reverse transcription-polymerase chain reaction (RT-PCR) and the nucleotide sequences were determined. In the 549 nucleotides (183 amino acids) of the entire 3C(pro), we found nucleotide differences at 80 positions between 10 strains and the prototype strain, EH24/70, one of the earliest strains of CA24v. Most of the nucleotide changes were synonymous substitutions and only nine amino acid changes were found. The nucleotide sequence homologies among 71 strains worldwide were 88-100%. These 71 nucleotide sequences were then analyzed by Neighbor-joining method and phylogenetically separated into three distinct genotypes. Genotype I consisted of early strains isolated in 1970--71 from Singapore and Hong Kong. Genotype II included isolates from Singapore and Thailand obtained in 1975. Genotype III comprised strains from the eastern hemisphere isolated in 1985--94 from Japan, Taiwan, China, Hong Kong, Thailand, Singapore, Pakistan and Ghana. They were further divided chronologically into six clusters. The recent isolates from Taiwan obtained in 1985/1986, 1988/1989 and 1990--94 were classified into genotype III Clusters 1, 5, and 6 respectively. The evolutionary rate was re-estimated to be 3 x 10(- 3) 30 years after the emergence of the virus.

Extracellular vesicle (EV)-mediated intercellular communication acts as a critical culprit in cancer development. The selective packaging of oncogenic molecules renders tumor-derived EVs capable of altering the tumor microenvironment and thereby modulating cancer developments that may contribute to drug resistance and cancer recurrence. Moreover, the molecular and functional characteristics of cancer through its development and posttreatment evolve over time. Tumor-derived EVs are profoundly involved in this process and can, therefore, provide valuable real-time information to reflect dynamic changes occurring within the body. Because they bear unique molecular profiles or signatures, tumor-derived EVs have been highlighted as valuable diagnostic and predictive biomarkers as well as novel therapeutic targets. In addition, the use of an advanced EV-based drug delivery system for cancer therapeutics has recently been emphasized in both basic and clinical studies. In this review, we highlight comprehensive aspects of tumor-derived EVs in oncogenic processes and their potential clinical applications.