Differential protein expression and novel biomarkers related to 5-FU resistance in a 3D colorectal adenocarcinoma model.

The multicellular spheroid (MCS) is an in vitro model which is highly representative of the avascular region of solid tumors by reflecting microenvironmental conditions in vivo. Hence, it is considered the most appropriate model for studying drug resistance. We compared chemosensitivity to 5-fluorouracil (5-FU) and differential protein expression between the 3D MCS model and the 2D monolayers using DLD-1 cells. We analyzed several significant signaling molecules through western blot analysis. Although various changes in the expression level were observed depending on the samples, we did not obtained remarkable findings. Notably, the level of p-mTOR decreased upon 5-FU exposure in the monolayers, while its level was higher in the MCSs. Nine novel proteins were identified by 2-DE and MALDI-TOF analysis for exhibiting differential expression between the MCS model and the monolayers. Among these, collapsin response mediator protein 2 (CRMP-2), DNA replication complex GINS protein PSF2 (PSF-2) and selenium-binding protein 1 (SBP-1) were notable not only for their differential expression but also for decreased expression following 5-FU exposure, indicating their possible roles as novel biomarkers for sensitivity (CRMP-2, PSF-2) as well as resistance (SBP-1) to 5-FU. Overall, the present study demonstrated greater 5-FU resistance in human colorectal cancer cells grown as MCSs compared to monolayers and identified p-mTOR, CRMP-2, PSF-2 and SBP-1 as novel potential biomarkers of 5-FU chemosensitivity/resistance for human colorectal cancer, findings which warrant further investigation.

Development of replication-competent adenovirus for bladder cancer by controlling adenovirus E1a and E4 gene expression with the survivin promoter.

Survivin is a member of the inhibitors of apoptosis protein family. Here, we examined survivin expression and confirmed abundant survivin expression in bladder cancer cells. This expression pattern indicated that the transcriptional regulatory elements that control survivin expression could be utilized to discriminate cancer from normal cells. We therefore generated a novel adenovirus termed Ad5/35E1apsurvivinE4 with the following characteristics: 1) E1A and E4 protein expression was dependent on survivin promoter activity; 2) the green fluorescence protein gene was inserted into the genome under the control of the CMV promoter; 3) most of the E3 sequences were deleted, but the construct was still capable of expressing the adenovirus death protein with potent cytotoxic effects; and 4) the fiber knob was from serotype 35 adenovirus. As expected from the abundant survivin expression observed in bladder cancer cells, Ad5/35E1apsurvivinE4 replicated better in cancer cells than in normal cells by a factor of 106 to 102. Likewise, Ad5/35E1apsurvivinE4 exerted greater cytotoxic effects on all bladder cancer cell lines tested. Importantly, Ad5/35E1apsurvivinE4 inhibited the growth of Ku7-Luc orthotopic xenografts in nude mice. Taken together, Ad5/35E1apsurvivinE4 indicates that the survivin promoter may be utilized for the development of a replication-competent adenovirus to target bladder cancers.

Proteasome inhibition causes epithelial-mesenchymal transition upon TM4SF5 expression.

Transmembrane 4 L six family member 5 (TM4SF5) is highly expressed in hepatocarcinoma and causes epithelial-mesenchymal transition (EMT) of hepatocytes. We found that TM4SF5-expressing cells showed lower mRNA levels but maintained normal protein levels in certain gene cases, indicating that TM4SF5 mediates stabilization of proteins. In this study, we explored whether regulation of proteasome activity and TM4SF5 expression led to EMT. We observed that TM4SF5 expression caused inhibition of proteasome activity and proteasome subunit expression, causing morphological changes and loss of cell-cell contacts. shRNA against TM4SF5 recovered proteasome expression, with leading to blockade of proteasome inactivation and EMT. Altogether, TM4SF5 expression appeared to cause loss of cell-cell adhesions via proteasome suppression and thereby proteasome inhibition, leading to repression of cell-cell adhesion molecules, such as E-cadherin.

The development of the conditionally replication-competent adenovirus: replacement of E4 orf1-4 region by exogenous gene.

BACKGROUND: Tumor or tissue specific replicative adenovirus armed with a therapeutic gene has shown a promising anti-cancer therapeutic modality. However, because the genomic packaging capacity is constrained, only a few places inside it are available for transgene insertion. In the present study, we introduce a novel strategy utilizing the early E4 region for the insertion of therapeutic gene(s). METHODS: We constructed the conditionally replication-competent adenovirus (CRAd), Ad5E4(mRFP) by: (i) replacing the E4/E1a promoter by the prostate-specific enhancer element; (ii) inserting mRFP inside the E4orf1-4 deletion region; and (iii) sub-cloning enhanced green fluorescent protein controlled by cytomegalovirus promoter in the left end of the viral genome. Subsequently, we evaluated its replication abilities and killing activities in vitro, as well as its in vivo anti-tumor efficacy in CWR22rv xenografts. RESULTS: When infected with Ad5E4(mRFP), the number and intensity of the mRFP gene products increased in a prostate cancer cell-specific manner as designed, suggesting that the mRFP gene and E4orfs other than E4orf1-4 were well synthesized from one transcript via alternative splicing as the recombinant adenovirus replicated. As expected from the confirmed virus replication capability, Ad5E4(mRFP) induced cell lysis as potent as the wild-type adenovirus and effectively suppressed tumor growth when tested in the CWR22rv xenografts in nude mice. Furthermore, Ad5E4(endo/angio) harboring an endostatin-angiostatin gene in E4orf1-4 was able to enhance CRAd by replacing mRFP with a therapeutic gene. CONCLUSIONS: The approach employed in the present study for the insertion of a therapeutic transgene in CRAd should facilitate the construction of CRAd containing multiple therapeutic genes in the viral genome that may have the potential to serve as highly potent cancer therapeutic reagents.

Genetic analysis of 10 unrelated Korean families with p22-phox-deficient chronic granulomatous disease: an unusually identical mutation of the CYBA gene on Jeju Island, Korea.

Chronic granulomatous disease (CGD) is a rare hereditary disorder characterized by recurrent life-threatening bacterial and fungal infections. The underlying defect in CGD is an inability of phagocytes to produce reactive oxygen species as a result of defects in NADPH oxidase. Considering that CGD generally affects about 3-4 in 1,000,000 individuals, it is surprising that the prevalence of CGD on Jeju Island is 20.7 in 1,000,000 individuals. We performed genetic analysis on 12 patients from 10 unrelated families and found that all patients had an identical homozygous single-base substitution of C to T in exon 1 (c.7C>T) of the CYBA gene, which was expected to result in a nonsense mutation (p.Q3X). Because Jeju Island has long been a geologically isolated region, the high prevalence of CGD on Jeju Island is presumably associated with an identical mutation inherited from a common ancestor or proband.

Molecular cloning and expression of the trichoderma harzianum C4 endo-beta-1,4-Xylanase Gene in Saccharomyces cerevisiae.

An endo-beta-1,4-xylanase (beta-xylanase) from Trichoderma harzianum C4 was purified without cellulase activity by sequential chromatographies. The specific activity of the purified enzyme preparation was 430 units/mg on D-xylan. The complementary DNA (cDNA) encoding beta-xylanase (xynII) was amplified by PCR and isolated from cDNA PCR libraries constructed from T. harzianum C4. The nucleotide sequence of the cDNA fragment contained an open reading frame of 663 bp that encodes 221 amino acids, of which the mature protein is homologous to several beta- xylanases II. An intron of 63 bp was identified in the genomic DNA sequence of xynII. This gene was expressed in Saccharomyces cerevisiae strains under the control of adh1 (alcohol dehydrogenase I) and pgk1 (phosphoglycerate kinase I) promoters in 2 mu-based plasmids, which could render recombinants able to secrete beta-xylanase into the media.