Genetic Polymorphism of PRKCDBP is Associated with an Increased Risk of Endometrial Cancer

Caveolae: Formation, dynamics, and function

Caveolae are abundant surface pits formed by the assembly of cytoplasmic proteins on a platform generated by caveolin integral membrane proteins and membrane lipids. This membranous assembly can bud off into the cell or can be disassembled releasing the cavin proteins into the cytosol. Disassembly can be triggered by increased membrane tension, or by stress stimuli, such as UV. Here, we discuss recent mechanistic studies showing how caveolae are formed and how their unique properties allow them to function as multifunctional protective and signaling structures.

Polymorphisms in PRKCDBP, a Transcriptional Target of TNF-α, Are Associated With Inflammatory Bowel Disease in Korean

Background/Aims

Emerging data indicate that polymorphic sequence variations in the tumor necrosis factor alpha (TNF-α) gene may affect its production, and be associated with the risk of inflammatory bowel disease (IBD). PRKCDBP is a putative tumor suppressor gene and a transcriptional target of TNF-α. The aim of this case-control study is to explore the possible association of single nucleotide polymorphisms (SNPs) in PRKCDBP with the development of IBD in Koreans.

Methods

Genotyping analysis of four SNPs of PRKCDBP [rs35301211 (G210A), rs11544766 (G237C), rs12294600 (C797T), and rs1051992 (T507C)] was performed on 170 ulcerative colitis (UC),131 Crohn's disease (CD) patients, and 100 unrelated healthy controls using polymerase chain reaction and restriction fragment length polymorphism.

Results

Heterozygous configuration of three SNPs (G210A, G237C, and C797T) was very rare in both patients and healthy controls. However, allele frequencies of the T507C SNP showed a significant difference between UC patients and controls (P=0.037). The CC genotype of the T507C SNP was identified in 46.6% (61 of 131) of CD and 49.4% (84 of 170) of UC patients, but only in 33.0% (33 of 100) of healthy controls. Furthermore, CC homozygosity was more prevalent than TC heterozygosity in both CD and UC patients versus controls (P=0.016; gender-adjusted odds ratio [aOR], 2.16; 95% confidence interval [CI], 1.16-4.04 and P=0.009; aOR, 2.09; 95% CI, 1.193.64; respectively)

Conclusions

Our results suggest that the T507C SNP in PRKCDBP, a TNF-α-inducible gene, might be associated with susceptibility to IBD (particularly UC) development in Koreans.

Elevation of PRKCDBP, a novel transcriptional target of TNF-α, and its downregulation by infliximab in patients with ulcerative colitis

BACKGROUND

Protein kinase C delta binding protein (PRKCDBP/Cavin3/hSRBC) is a putative tumor suppressor that is downregulated in many human cancers. Recently, PRKCDBP was identified to be activated by nuclear factor-κB in response to tumor necrosis factor (TNF)-α.

AIMS

To explore the potential of PRKCDBP as a diagnostic or prognostic marker for inflammatory bowel disease, the possible correlation between its expression status and TNF-α signaling was evaluated in ulcerative colitis (UC) patients, both pre- and post-infliximab (IFX) therapy.

METHODS

In total, 31 IFX therapy-naïve patients (13 females; median age, 41 years) with moderate-to-severe UC who had been scheduled for IFX treatment were included. Immunohistochemical analysis of TNF-α and PRKCDBP expression was performed in rectal biopsies.

RESULTS

A significant correlation was observed in immunoreactivity between TNF-α and PRKCDBP. IFX therapy reduced immunohistochemical expression of PRKCDBP and TNF-α (P < 0.001 and P = 0.005, respectively). The mean PRKCDBP expression level decreased from 54.5 to 30.2%, and that of TNF-α decreased from 54.5 to 36.2%. The immunohistochemical expression pre- and post-PRKCDBP therapy correlated significantly with TNF-α levels pre- and post-therapy (Spearman's rank correlation test; P = 0.005 and P = 0.001, respectively).

CONCLUSIONS

These results demonstrate that mucosal expression of PRKCDBP correlated strongly with TNF-α expression in UC patients and that IFX therapy resulted in profound reductions in both PRKCDBP and TNF-α. Thus, these findings support that PRKCDBP expression is tightly controlled by TNF-α, and the anti-inflammatory effect of IFX may in part stem from blockade of the TNF-α-PRKCDBP signaling pathway.

HeLa cell response proteome alterations induced by mammalian reovirus T3D infection

Background

Cells are exposed to multiple stressors that induce significant alterations in signaling pathways and in the cellular state. As obligate parasites, all viruses require host cell material and machinery for replication. Virus infection is a major stressor leading to numerous induced modifications. Previous gene array studies have measured infected cellular transcriptomes. More recently, mass spectrometry-based quantitative and comparative assays have been used to complement such studies by examining virus-induced alterations in the cellular proteome.

Methods

We used SILAC (stable isotope labeling with amino acids in cell culture), a non-biased quantitative proteomic labeling technique, combined with 2-D HPLC/mass spectrometry and reciprocal labeling to identify and measure relative quantitative differences in HeLa cell proteins in purified cytosolic and nuclear fractions after reovirus serotype 3 Dearing infection. Protein regulation was determined by z-score analysis of each protein’s label distribution.

Results

A total of 2856 cellular proteins were identified in cytosolic fractions by 2 or more peptides at >99% confidence and 884 proteins were identified in nuclear fractions. Gene ontology analyses indicated up-regulated host proteins were associated with defense responses, immune responses, macromolecular binding, regulation of immune effector processes, and responses to virus, whereas down-regulated proteins were involved in cell death, macromolecular catabolic processes, and tissue development.

Conclusions

These analyses identified numerous host proteins significantly affected by reovirus T3D infection. These proteins map to numerous inflammatory and innate immune pathways, and provide the starting point for more detailed kinetic studies and delineation of virus-modulated host signaling pathways.