ABSTRACT
<p><b>BACKGROUND</b>Mounting evidence suggests that tumors are histologically heterogeneous and are maintained by a small population of tumor cells termed cancer stem cells. CD133 has been identified as a candidate marker of cancer stem cells in laryngeal carcinoma. This study aimed to analyze the chemoresistance of CD133(+) cancer stem cells.</p><p><b>METHODS</b>The response of Hep-2 cells to different chemotherapeutic agents was investigated and the expression of CD133 was studied. Fluorescence-activated cell sorting analysis was used to identify CD133, and the CD133(+) subset of cells was separated and analyzed in colony formation assays, cell invasion assays, chemotherapy resistance studies, and analyzed for the expression of the drug resistance gene ABCG2.</p><p><b>RESULTS</b>About 1% - 2% of Hep-2 cells were CD133(+) cells, and the CD133(+) proportion was enriched by chemotherapy. CD133(+) cancer stem cells exhibited higher potential for clonogenicity and invasion, and were more resistant to chemotherapy. This resistance was correlated with higher expression of ABCG2.</p><p><b>CONCLUSIONS</b>This study suggested that CD133(+) cancer stem cells are more resistant to chemotherapy. The expression of ABCG2 could be partially responsible for this. Targeting this small population of CD133(+) cancer stem cells could be a strategy to develop more effective treatments for laryngeal carcinoma.</p>
Subject(s)
Humans , AC133 Antigen , ATP Binding Cassette Transporter, Subfamily G, Member 2 , ATP-Binding Cassette Transporters , Genetics , Metabolism , Antigens, CD , Genetics , Metabolism , Antineoplastic Agents , Pharmacology , Blotting, Western , Carcinoma , Genetics , Metabolism , Cell Line, Tumor , Cisplatin , Pharmacology , Flow Cytometry , Fluorouracil , Pharmacology , Glycoproteins , Genetics , Metabolism , Laryngeal Neoplasms , Genetics , Metabolism , Neoplasm Proteins , Genetics , Metabolism , Neoplastic Stem Cells , Cell Biology , Metabolism , Paclitaxel , Pharmacology , Peptides , Genetics , Metabolism , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
<p><b>OBJECTIVE</b>To study the effect of silencing survivin on the growth of Hep-2 human laryngeal cancer cells in vitro and in vivo.</p><p><b>METHODS</b>Hep-2 cells were transfected with pGCsilencer-siRNA-survivin (psi-survivin)by Lipofectamine 2000. The mRNA and protein expressions of survivin were detected by semi-quantitative RT-PCR and Western blot, respectively. Cell proliferation activity was measured by MTT assay. Apoptosis was assessed by flow cytometry. The implanted tumors were formed from injected Hep-2 cells in nude mice. After the tumor formation, psi-survivin was injected into peritumor tissues. The growth of tumor were observed. The tumor volume was calculated and the tumor growth curve was plotted. The expression of survivin in tumor tissues was detected by Western blot. The tumor cell apoptosis was observed by Tunel staining.</p><p><b>RESULTS</b>The sequence-specific siRNA of survivin inhibited the expressions of survivin mRNA and protein. The inhibition rates of survivin mRNA and protein expression were 54.4% and 37.0% respectively. Also the growth of Hep-2 cells was inhibited significantly, with a decrease by 71.7%. By the day 32 of tumor growth, the mean tumor volumes were (1443.9 ± 230.5) mm(3) (x(-) ± s) in saline control group, (1348.5 ± 198.4) mm(3) in plasmid-negative control group, and (624.6 ± 188.4) mm(3) in psi-survivin group, respectively (t = -5.917, P < 0.01). In the implanted tumors injected with psi-survivin, survivin protein expression was down-regulated significantly, with a inhibition rate of 41.8%. Tunel staining showed the apoptosis occurred in the implanted tumors.</p><p><b>CONCLUSION</b>Silencing survivin could significantly inhibit the growth of Hep-2 human laryngeal cancer cells in vitro and in vivo.</p>