Alteration of nuclear matrix-intermediate filament system and differential expression of nuclear matrix proteins during human hepatocarcinoma cell differentiation

Abstract

AIM:To investigate the association between the configurational and compositional changes of nuclear matrix and the differentiation of carcinoma cells. METHODS:Cells cultured with or without 5 × 10 -3 mmol/L of hexamethylene bisacetamide (HMBA) on Nickel grids were treated by selective extraction and prepared for whole mount observation under electron m i c ro s c o p y. T h e s a m p l e s w e re e x a m i n e d u n d e r transmission electron microscope. Nuclear matrix proteins were selectively extracted and subjected to subcellular proteomics study. The protein expression patterns were analyzed by PDQuest software. Spots of differentially expressed nuclear matrix proteins were excised and subjected to in situ digestion with trypsin.The peptides were analyzed by matrix-assisted laserdesorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Data were submitted for database searching using Mascot tool (www.matrixscience.com). RESULTS:The nuclear matrix (NM) and intermediate filament (IF) in SMMC-7721 hepatocarcinoma cells were found relatively sparse and arranged irregularly. The nuclear lamina was non-uniform, and two kinds of filaments were not tightly connected. After induction for differentiation by HMBA, the NM-IF filaments were concentrated and distributed uniformly. The heterogeneous population of filaments, including highly branched utrathin filaments could also be seen in the regular meshwork. The connection between the two kinds of filaments and the relatively thin, condensed and sharply demarcated lamina composed of intermediatesized filaments was relatively fastened. Meanwhile, 21 NM proteins changed remarkably during SMMC-7721 cell differentiation. Four proteins, i.e. mutant Pyst1, hypothetical protein, nucleophosmin1, and LBP were downregulated, whereas four other proteins, eIF6, p44 subunit, β-tubulin, and SIN3B were upregulated with the last one, SR2/ASF found only in the differentiated SMMC-7721 cells. CONCLUSION:The induced differentiation of SMMC-7721 cells by HMBA is accompanied by the configurational changes of nuclear matrix-intermediate filament (NM-IF) system and the compositional changes of nuclear matrix protein expression. These changes may be important morphological or functional indications of the cancer cell reversion.

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

“…However, in our study, the functions and mechanisms of Bβ10-42 in the procedure of HBV related liver diseases are still not explicit. NPM, an established marker for the granular components [32,33], can cause the suppression of cell differentiation and anti-apoptosis in human carcinogenesis, especially in hepatocellular carcinoma [34][35][36]. NPM decreased during HBV infection and the mechanism should be further investigated.…”

SIN3B promotes integrin αV subunit gene transcription and cell migration of hepatocellular carcinoma

“…Chromosone-associated SIN3B was thus proved important in PTEN-induced cell senescence and thereto prevented progression to invasive prostate adenocarcinoma. In human hepatocarcinoma cells (HCC), SIN3B was upregulated in the hexamethylene bisacetamide (HMBA)-induced differentiation ( Tang et al, 2007 ). But the expression levels of MAD1, the member of MXD family, reduced in HCC tissues ( Nam et al, 2008 ).…”

Regulatory role of nucleophosmin during the differentiation of human liver cancer cells

“…In our previous study, we found NPM was a nuclear matrix protein and its expression was downregulated in the induced differentiation of human osteosarcoma, human neuroblastoma tumors and human liver cancer (6)(7)(8), indicating NPM functioned in regulating the differentiation of tumor cells (9). Liver cancer is the most common malignant gastrointestinal cancer and the screening for functional proteins related to liver tumor cell differentiation will contribute to the elucidation of the mechanism of liver cancer development and its early diagnosis.…”