Effect of sodium butyrate on ABC transporters in lung cancer A549 and colorectal cancer HCT116 cells.

Histone deacetylase (HDAC) inhibitors and DNA alkylators are effective components of combination chemotherapy. The aim of the present study was to investigate the possible mechanism of their synergism by detecting the effect of HDAC inhibitors on the expression levels of drug transporters that export DNA alkylators. It was demonstrated that the HDAC inhibitor sodium butyrate (NaB) induced the differential expression of multidrug resistant ATP-binding cassette (ABC) transporters in lung cancer and colorectal cancer cells. Specifically, NaB increased the mRNA expression levels of ABC subfamily B member 1 (ABCB1), ABCC10 and ABCC12, and protein expression levels of multidrug resistance-1 (MDR1), multidrug resistance-associated protein 7 (MRP7) and MRP9. Moreover, NaB decreased the expression levels of ABCC1, ABCC2 and ABCC3 mRNAs, as well as those of MRP1, MRP2 and MRP3 proteins. The molecular mechanism underlying this process was subsequently investigated. NaB decreased the expression of HDAC4, but not HDAC1, HDAC2 or HDAC3. In addition, NaB promoted histone H3 acetylation and methylation at lysine 9, as well as MDR1 acetylation, suggesting that acetylation and methylation may be involved in NaB-mediated ABC transporter expression. Thus, the present results indicated that the synergism of the HDAC inhibitors with the DNA alkylating agents may due to the inhibitory effect of MRPs by HDAC inhibitors. The findings also suggested the possibility of antagonistic effects following the combined treatment of HDAC inhibitors with MDR1 ligands.

Quantitative and noninvasive assessment of chronic liver diseases using two-dimensional shear wave elastography.

Two-dimensional shear wave elastography (2D-SWE) is a rapid, simple and novel noninvasive method that has been proposed for assessing hepatic fibrosis in patients with chronic liver diseases (CLDs) based on measurements of liver stiffness. 2D-SWE can be performed easily at the bedside or in an outpatient clinic and yields immediate results with good reproducibility. Furthermore, 2D-SWE was an efficient method for evaluating liver fibrosis in small to moderately sized clinical trials. However, the quality criteria for the staging of liver fibrosis are not yet well defined. Liver fibrosis is the main pathological basis of liver stiffness and a key step in the progression from CLD to cirrhosis; thus, the management of CLD largely depends on the extent and progression of liver fibrosis. 2D-SWE appears to be an excellent tool for the early detection of cirrhosis and may have prognostic value in this context. Because 2D-SWE has high patient acceptance, it could be useful for monitoring fibrosis progression and regression in individual cases. However, multicenter data are needed to support its use. This study reviews the current status and future perspectives of 2D-SWE for assessments of liver fibrosis and discusses the technical advantages and limitations that impact its effective and rational clinical use.

Inhibition of tumor growth by S-3-1, a synthetic intermediate of salvianolic acid A.

Salvianolic acid A (1) is one of the active components from Salvia miltiorrhiza, which was found to suppress the growth of mouse tumors. S-3-1 (a 2-allyl-3,4-dihydroxybenzaldehyde, 2) is a synthetic intermediate of a salvianolic acid A derivative with strong inhibitory effects on the growth of cancer cells in vitro. The inhibitory effects of 2 on tumor growth and its molecular targets were studied. 2 significantly suppressed the growth of mouse Lewis lung carcinoma, S180 sarcoma and H22 hepatic carcinoma in a dose-dependent manner. With a simple scrape-loading dye transfer method, 20 microg/ml of 2 was found to significantly enhance gap junction intercellular communication (GJIC) in human pancreatic adenocarcinoma PaCa Cells, human lung epithelial carcinoma W1-38 cells and human lung adenocarcinoma A549 cells, but 2 had no marked effect on GJIC in human colon cancer CACO2 cells. With Northern blot analysis, 2 was found to inhibit the expression of c-myc gene in A549 cells and have no marked effect on H-ras oncogene expression, and increase the cellular P53 mRNA contents, though it did not affect the expression of RB tumor suppressor gene. 2 also suppressed the P46 (JNK/SAPK) expression in A549 cells. Western blot analysis was applied to visualize the P21ras protein. Results shows that 2 at concentrations ranging from 10 to 20 microg/ml decreases the contents of the membranous P21ras and total P21ras and increases the contents of cytosolic P21ras protein in a time-dependent manner. However, 2 had no significant effects on farnesyl protein transferase activities at the concentrations that could efficiently decrease the membranous P21ras content. This suggested that 2 might suppress tumor growth partly through enhancement of GJIC and reversion of the transformed phenotypes. The other mechanisms may be that 2 can suppress the overexpression of c-myc oncogene, inhibit the function of Ras oncoprotein, increase the expression of P53 tumor suppressor gene and interrupt P46-associated mitogen-activated pathway other than farnesylation of Ras protein.