Effects of microRNA-29 family members on proliferation and invasion of gastric cancer cell lines / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>MicroRNAs have emerged as post-transcriptional regulators that are critically involved in the biologic behavior of cells. This study was designed to investigate the effect of members of the microRNA-29 family on the expression of cell division cycle 42 (Cdc42) and their roles on proliferation, migration, and invasion of gastric cancer cells.</p><p><b>METHODS</b>We detected microRNA-29s and Cdc42 expression in gastric cancer cells by real-time polymerase chain reaction (PCR) and Western blot analysis. Negative controlled RNA (ncontrol), microRNA-29 family members (microRNA-29a, -29b, and -29c), and Cdc42-specific small interfering RNA (si-Cdc42) were chemically synthesized and transfected into SGC7901 and BGC823 gastric cancer cells, which have a relatively low expression of microRNA-29s and a relatively high expression of Cdc42. The expression of Cdc42 and the phosphorylation of its downstream molecular PAK1 expressions were determined by Western bolt analysis. Cell Counting Kit-8 was used to measure cell proliferation, and wound-healing and invasion assays were used to examine the abilities of migration and invasion.</p><p><b>RESULTS</b>Similar to si-Cdc42, the ectopic expression of microRNA-29 family members significantly reduced the expression of Cdc42 and its downstream molecular PAK1 phosphorylation levels. Consistently, ectopic expression of microRNA-29s inhibited proliferation and migration in gastric cancer cells. Invasive cell counts of the SGC7901, ncontrol/SGC7901, si-Cdc42/SGC7901, microRNA-29a/SGC7901, microRNA-29b/SGC7901, and microRNA-29c/SGC7901 cell groups were 84.0+/-4.2, 71.7+/-4.6, 16.3+/-3.2, 15.7+/-3.8, 16.3+/-3.0, and 16.7+/-3.1, respectively. The invasive cell counts of the BGC823, ncontrol/BGC823, si-Cdc42/BGC823, microRNA-29a/BGC823, microRNA-29b/BGC823, and microRNA-29c/BGC823 cell groups were 199.0+/-10.5, 146.3+/-9.7, 72.7+/-8.2, 86.7+/-8.5, 86.0+/-8.5, and 73.3+/-8.3, respectively (P<0.05).</p><p><b>CONCLUSIONS</b>Members of the microRNA-29 family can obviously inhibit cell proliferation, migration, and invasion of gastric cancer cells by targeting Cdc42.</p>

Establishment and biological characteristics of oxaliplatin-resistant human colon cancer cell lines / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Chemotherapy is the main treatment for colon cancer, while multidrug-resistance is the main reason for chemotherapy failure and tumor relapse. This study was to establish two oxaliplatin-resistant colon cancer cell lines and evaluate their biological characteristics.</p><p><b>METHODS</b>Oxaliplatin-resistant colon cancer cell lines SW620/L-OHP and lovo/L-OHP were established in vitro by continuous exposure to oxaliplatin (L-OHP) of low and gradually increased concentration. Growth curve, cross-resistance and resistance index of the oxaliplatin-resistant cell lines to various anti-cancer agents were determined by CCK8 assay. The expressions of P-glycoprotein (P-gp), multidrug-resistance protein 1 (MRP1) and MRP2 were detected by Western blot. Cell cycle distribution as well as the expression of CD133 and CD44 were measured by flow cytometry.</p><p><b>RESULTS</b>It took 10 months to establish the SW620/L-OHP and LoVo/L-OHP cell lines with stable resistance to oxaliplatin. Cross-resistance to 5-fluorouracil, etoposide, cisplatin, vincristine and epirubicin but not to paclitaxel was observed. Longer doubling time, higher proportion of cells in G(0)/G(1) phase and lower proportion in G(2)/M phase were observed in the two oxaliplatin-resistant cell lines compared with their parental cell lines. The expression of MRP2 in the oxaliplatin-resistant cells was up-regulated, while those of P-gp and MRP1 had no significant change. CD133 was overexpressed while CD44 level remained unchanged in SW620/L-OHP and LoVo/L-OHP cells.</p><p><b>CONCLUSIONS</b>SW620/L-OHP and LoVo/L-OHP cell lines show a typical and stably resistant phenotype and may be used as research models.</p>