Aberrant expression of nuclear matrix proteins during HMBA-induced differentiation of gastric cancer cells

Abnormal Expression of PICT-1 and Its Codon 389 Polymorphism Is a Risk Factor for Human Endometrial Cancer

OBJECTIVE

The protein interacting with carboxyl terminus-1 (PICT-1) gene has been implicated as a tumor suppressor gene, and its alterations have been reported in several cancers. This study investigated the association of PICT-1 alterations with endometrial carcinogenesis.

METHODS

We analyzed the entire coding region of the PICT-1 gene using polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing to examine PICT-1 mutations in endometrial cancer. Western blotting and immunohistochemical staining were performed to analyze the protein expression and cellular localization of PICT-1 in endometrial cancer cell lines and patient samples.

RESULTS

The codon 389 polymorphism of PICT-1 increased the risk of endometrial cancer. Interestingly, 2 of 13 endometrial cancers somatically acquired this mutation compared to normal counterparts. Immunohistochemical staining revealed lower levels of PICT-1 in samples from atypical endometrial hyperplasia and endometrial cancer tissues compared to normal endometrial tissues (p < 0.01). This decrease in PICT-1 expression was significantly correlated with histological grade and lymph node metastasis (p < 0.05).

CONCLUSIONS

The findings of this study suggest that disruption of PICT-1 protein expression and codon 389 polymorphism can contribute to the pathogenesis or neoplastic progression of endometrial cancer.

14-3-3ε is a nuclear matrix protein, and its altered expression and localization are associated with curcumin-induced apoptosis of MG-63 cells

The 14-3-3 protein family may regulates protein interaction, transportation and cellular localization. The regulatory role of 14-3-3ε is influenced by its altered localization. In the present study, human osteosarcoma MG-63 cells were treated with curcumin to induce apoptosis. Subsequently, the altered expression and localization of 14-3-3ε and its co-localization with other apoptosis-associated proteins during apoptosis was investigated. Analysis of nuclear matrix proteins (NMPs), using two-dimensional gel electrophoresis with matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry, revealed that 14-3-3ε existed on the nuclear matrix of MG-63 cells, and its expression was decreased compared with that in control cells following curcumin treatment. In addition, western blot analysis validated that the expression level of 14-3-3ε was downregulated during curcumin-induced apoptosis of MG-63 cells compared with that in control cells. Using immunofluorescence labeling, it was observed that 14-3-3ε was located on the nuclear matrix of MG-63 cells and the distribution of 14-3-3ε on the nuclear matrix was decreased following treatment with curcumin, compared with that in control cells. Double immunofluorescence staining and laser-scanning confocal microscopy demonstrated that 14-3-3ε was co-localized with B-cell lymphoma-2 (Bcl-2), Bcl-2-associated-X protein, p53 and c-FOS transcription factor in MG-63 cells. Furthermore, following treatment with curcumin, these co-localization regions were decreased. The results of the present study revealed that 14-3-3ε is an NMP in MG-63 cells, and its altered expression and co-localization with apoptosis-associated proteins indicated an important function of 14-3-3ε in apoptosis of MG-63 cells. Additional studies are required to investigate the results of the present study.

Nanoparticle-conjugated aptamer targeting hnRNP A2/B1 can recognize multiple tumor cells and inhibit their proliferation

In this study, we further investigated a previously developed aptamer targeting ROS 17/2.8 (rat osteosarcoma) cells. We found that this C6-8 aptamer specifically binds to heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 and that it specifically labeled multiple tumor-cell lines as effectively as hnRNP A2/B1 monoclonal antibodies. When conjugated with fluorescent carbon nanodots (CDots) it could freely enter multiple living tumor cell lines (HepG2, MCF-7, H1299, and HeLa), whose growth it inhibited by targeting hnRNP A2/B1. Similar inhibitory effects were observed when the GFP-HepG2 hepatocarcinoma cells treated with C6-8-conjugated CDots were implanted in nude mice. Our work provides a new aptamer for targeting/labeling multiple tumor cell types, and its nanoparticle conjugates bring further advantages that increase its potential for use in cancer diagnosis and therapy.

The aberrant expression and localization of prohibitin during apoptosis of human cholangiocarcinoma Mz-ChA-1 cells

In this study, we aimed to investigate the aberrant expression and shift in localization of prohibitin (PHB) during apoptosis of human cholangiocarcinoma cells. Our study demonstrated that PHB was expressed primarily in the cytoplasm and only a little in the nucleus. However, PHB expression significantly decreased, and its localization shifted from the cytoplasm to the nucleus during apoptosis. PHB co-localized with AIF, Rb, p53, and c-Fos, but the region of co-localization was altered after treatment. Meanwhile, we detected a direct interaction between PHB and both p53 and Rb in Mz-ChA-1 cells. These results suggest that the altered localization and expression of PHB, as well as its co-localization with related oncogenes and tumor suppressor genes, can affect the apoptosis of Mz-ChA-1 cells.

The differential diagnostic model for serous peptidomics in HBV carriers established by MALDI-TOF-MS analysis

OBJECTIVES

Hepatitis B virus (HBV) can result in asymptomatic carrier (AsC) state or chronic inflammation of liver, which depends on the host immunity. We therefore investigated the peptidomic profiling in the process of HBV infection.

DESIGN AND METHODS

In this study, serum from 116 HBV infected (AsC and chronic hepatitis), 60 HBV-immunized and 70 normal subjects was treated with MB-WCX (weak cation exchange based magnetic beads) kits and analyzed by the Clinprot/Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) techniques. Purified serous proteins were subjected to FT-ICR-MS analysis, and Western blot further confirmed the results.

RESULTS

The specific model comprised of two peptides m/z 2882.89 and 4476.12 could distinguish HBV infected from healthy (HBV-immunized and normal) group and showed 95.5% of the sensitivity and 95.4% of the specificity by cross-validation analysis. 40/56 HBV infected and 43/50 healthy subjects could be correctly classified by the model. The area under the receiving operating curves (AUROC) of m/z 2882.89 and 4476.12, identified as subunits of fibrinogen beta chain (FBG) Bβ10-42 and nucleophosmin (NPM) respectively, were both up to 0.88 when discriminating AsC from the healthy group. The expression of Bβ10-42 and NPM decreased significantly in the plasma of HBV infected individuals by Western blot analysis.

CONCLUSIONS

There were specific serum peptide profilings for host responses to HBV infection, and m/z 2882.89 and 4476.12 could be valuable follow-up and prognostic tools for HBV infection.