BackgroundBurkholderia pseudomallei is the causative agent of melioidosis where the highest reported incidence world wide is in the Northeast of Thailand, where saline soil and water are prevalent. Moreover, recent reports indicate a potential pathogenic role for B. pseudomallei in cystic fibrosis lung disease, where an increased sodium chloride (NaCl) concentration in airway surface liquid has been proposed. These observations raise the possibility that high salinity may represent a favorable niche for B. pseudomallei. We therefore investigated the global transcriptional response of B. pseudomallei to increased salinity using microarray analysis.ResultsTranscriptome analysis of B. pseudomallei under salt stress revealed several genes significantly up-regulated in the presence of 320 mM NaCl including genes associated with the bsa-derived Type III secretion system (T3SS). Microarray data were verified by reverse transcriptase-polymerase chain reactions (RT-PCR). Western blot analysis confirmed the increased expression and secretion of the invasion-associated type III secreted proteins BipD and BopE in B. pseudomallei cultures at 170 and 320 mM NaCl relative to salt-free medium. Furthermore, salt-treated B. pseudomallei exhibited greater invasion efficiency into the lung epithelial cell line A549 in a manner partly dependent on a functional Bsa system.ConclusionsB. pseudomallei responds to salt stress by modulating the transcription of a relatively small set of genes, among which is the bsa locus associated with invasion and virulence. Expression and secretion of Bsa-secreted proteins was elevated in the presence of exogenous salt and the invasion efficiency was enhanced. Our data indicate that salinity has the potential to influence the virulence of B. pseudomallei.

TFF1 trefoil protein could be one of the effectors for estrogen-induced invasion in cholangiocarcinoma via the estrogen receptor-α. These findings could lead to an understanding of the mechanism of cholangiocarcinoma progression.

Colorectal cancer (CRC) is the most common gastrointestinal malignancy worldwide with a remarkably high mortality rate. 1 It is the second leading cause of cancer death and over 50,000 deaths annually are estimated in the United States. 2 The prognosis of CRC is clearly related to the level of the tumour penetration through the bowel wall and the presence or absence of nodal invasion. 3 The mechanism of how CRC cells can migrate and metastasize is an active field of study. Periostin (PN) is a secreted extracellular matrix protein mainly produced by mesenchymal fibroblasts in osteoblasts, periosteum,